diff.c

   1 /*
   2  * Copyright (C) 2005 Junio C Hamano
   3  */
   4 #include "cache.h"
   5 #include "config.h"
   6 #include "tempfile.h"
   7 #include "quote.h"
   8 #include "diff.h"
   9 #include "diffcore.h"
  10 #include "delta.h"
  11 #include "xdiff-interface.h"
  12 #include "color.h"
  13 #include "attr.h"
  14 #include "run-command.h"
  15 #include "utf8.h"
  16 #include "userdiff.h"
  17 #include "submodule-config.h"
  18 #include "submodule.h"
  19 #include "ll-merge.h"
  20 #include "string-list.h"
  21 #include "argv-array.h"
  22 #include "graph.h"
  23
  24 #ifdef NO_FAST_WORKING_DIRECTORY
  25 #define FAST_WORKING_DIRECTORY 0
  26 #else
  27 #define FAST_WORKING_DIRECTORY 1
  28 #endif
  29
  30 static int diff_detect_rename_default;
  31 static int diff_indent_heuristic = 1;
  32 static int diff_rename_limit_default = 400;
  33 static int diff_suppress_blank_empty;
  34 static int diff_use_color_default = -1;
  35 static int diff_context_default = 3;
  36 static int diff_interhunk_context_default;
  37 static const char *diff_word_regex_cfg;
  38 static const char *external_diff_cmd_cfg;
  39 static const char *diff_order_file_cfg;
  40 int diff_auto_refresh_index = 1;
  41 static int diff_mnemonic_prefix;
  42 static int diff_no_prefix;
  43 static int diff_stat_graph_width;
  44 static int diff_dirstat_permille_default = 30;
  45 static struct diff_options default_diff_options;
  46 static long diff_algorithm;
  47 static unsigned ws_error_highlight_default = WSEH_NEW;
  48
  49 static char diff_colors[][COLOR_MAXLEN] = {
  50         GIT_COLOR_RESET,
  51         GIT_COLOR_NORMAL,       /* CONTEXT */
  52         GIT_COLOR_BOLD,         /* METAINFO */
  53         GIT_COLOR_CYAN,         /* FRAGINFO */
  54         GIT_COLOR_RED,          /* OLD */
  55         GIT_COLOR_GREEN,        /* NEW */
  56         GIT_COLOR_YELLOW,       /* COMMIT */
  57         GIT_COLOR_BG_RED,       /* WHITESPACE */
  58         GIT_COLOR_NORMAL,       /* FUNCINFO */
  59 };
  60
  61 static NORETURN void die_want_option(const char *option_name)
  62 {
  63         die(_("option '%s' requires a value"), option_name);
  64 }
  65
  66 static int parse_diff_color_slot(const char *var)
  67 {
  68         if (!strcasecmp(var, "context") || !strcasecmp(var, "plain"))
  69                 return DIFF_CONTEXT;
  70         if (!strcasecmp(var, "meta"))
  71                 return DIFF_METAINFO;
  72         if (!strcasecmp(var, "frag"))
  73                 return DIFF_FRAGINFO;
  74         if (!strcasecmp(var, "old"))
  75                 return DIFF_FILE_OLD;
  76         if (!strcasecmp(var, "new"))
  77                 return DIFF_FILE_NEW;
  78         if (!strcasecmp(var, "commit"))
  79                 return DIFF_COMMIT;
  80         if (!strcasecmp(var, "whitespace"))
  81                 return DIFF_WHITESPACE;
  82         if (!strcasecmp(var, "func"))
  83                 return DIFF_FUNCINFO;
  84         return -1;
  85 }
  86
  87 static int parse_dirstat_params(struct diff_options *options, const char *params_string,
  88                                 struct strbuf *errmsg)
  89 {
  90         char *params_copy = xstrdup(params_string);
  91         struct string_list params = STRING_LIST_INIT_NODUP;
  92         int ret = 0;
  93         int i;
  94
  95         if (*params_copy)
  96                 string_list_split_in_place(&params, params_copy, ',', -1);
  97         for (i = 0; i < params.nr; i++) {
  98                 const char *p = params.items[i].string;
  99                 if (!strcmp(p, "changes")) {
 100                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 101                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 102                 } else if (!strcmp(p, "lines")) {
 103                         DIFF_OPT_SET(options, DIRSTAT_BY_LINE);
 104                         DIFF_OPT_CLR(options, DIRSTAT_BY_FILE);
 105                 } else if (!strcmp(p, "files")) {
 106                         DIFF_OPT_CLR(options, DIRSTAT_BY_LINE);
 107                         DIFF_OPT_SET(options, DIRSTAT_BY_FILE);
 108                 } else if (!strcmp(p, "noncumulative")) {
 109                         DIFF_OPT_CLR(options, DIRSTAT_CUMULATIVE);
 110                 } else if (!strcmp(p, "cumulative")) {
 111                         DIFF_OPT_SET(options, DIRSTAT_CUMULATIVE);
 112                 } else if (isdigit(*p)) {
 113                         char *end;
 114                         int permille = strtoul(p, &end, 10) * 10;
 115                         if (*end == '.' && isdigit(*++end)) {
 116                                 /* only use first digit */
 117                                 permille += *end - '0';
 118                                 /* .. and ignore any further digits */
 119                                 while (isdigit(*++end))
 120                                         ; /* nothing */
 121                         }
 122                         if (!*end)
 123                                 options->dirstat_permille = permille;
 124                         else {
 125                                 strbuf_addf(errmsg, _("  Failed to parse dirstat cut-off percentage '%s'\n"),
 126                                             p);
 127                                 ret++;
 128                         }
 129                 } else {
 130                         strbuf_addf(errmsg, _("  Unknown dirstat parameter '%s'\n"), p);
 131                         ret++;
 132                 }
 133
 134         }
 135         string_list_clear(&params, 0);
 136         free(params_copy);
 137         return ret;
 138 }
 139
 140 static int parse_submodule_params(struct diff_options *options, const char *value)
 141 {
 142         if (!strcmp(value, "log"))
 143                 options->submodule_format = DIFF_SUBMODULE_LOG;
 144         else if (!strcmp(value, "short"))
 145                 options->submodule_format = DIFF_SUBMODULE_SHORT;
 146         else if (!strcmp(value, "diff"))
 147                 options->submodule_format = DIFF_SUBMODULE_INLINE_DIFF;
 148         else
 149                 return -1;
 150         return 0;
 151 }
 152
 153 static int git_config_rename(const char *var, const char *value)
 154 {
 155         if (!value)
 156                 return DIFF_DETECT_RENAME;
 157         if (!strcasecmp(value, "copies") || !strcasecmp(value, "copy"))
 158                 return  DIFF_DETECT_COPY;
 159         return git_config_bool(var,value) ? DIFF_DETECT_RENAME : 0;
 160 }
 161
 162 long parse_algorithm_value(const char *value)
 163 {
 164         if (!value)
 165                 return -1;
 166         else if (!strcasecmp(value, "myers") || !strcasecmp(value, "default"))
 167                 return 0;
 168         else if (!strcasecmp(value, "minimal"))
 169                 return XDF_NEED_MINIMAL;
 170         else if (!strcasecmp(value, "patience"))
 171                 return XDF_PATIENCE_DIFF;
 172         else if (!strcasecmp(value, "histogram"))
 173                 return XDF_HISTOGRAM_DIFF;
 174         return -1;
 175 }
 176
 177 static int parse_one_token(const char **arg, const char *token)
 178 {
 179         const char *rest;
 180         if (skip_prefix(*arg, token, &rest) && (!*rest || *rest == ',')) {
 181                 *arg = rest;
 182                 return 1;
 183         }
 184         return 0;
 185 }
 186
 187 static int parse_ws_error_highlight(const char *arg)
 188 {
 189         const char *orig_arg = arg;
 190         unsigned val = 0;
 191
 192         while (*arg) {
 193                 if (parse_one_token(&arg, "none"))
 194                         val = 0;
 195                 else if (parse_one_token(&arg, "default"))
 196                         val = WSEH_NEW;
 197                 else if (parse_one_token(&arg, "all"))
 198                         val = WSEH_NEW | WSEH_OLD | WSEH_CONTEXT;
 199                 else if (parse_one_token(&arg, "new"))
 200                         val |= WSEH_NEW;
 201                 else if (parse_one_token(&arg, "old"))
 202                         val |= WSEH_OLD;
 203                 else if (parse_one_token(&arg, "context"))
 204                         val |= WSEH_CONTEXT;
 205                 else {
 206                         return -1 - (int)(arg - orig_arg);
 207                 }
 208                 if (*arg)
 209                         arg++;
 210         }
 211         return val;
 212 }
 213
 214 /*
 215  * These are to give UI layer defaults.
 216  * The core-level commands such as git-diff-files should
 217  * never be affected by the setting of diff.renames
 218  * the user happens to have in the configuration file.
 219  */
 220 void init_diff_ui_defaults(void)
 221 {
 222         diff_detect_rename_default = 1;
 223 }
 224
 225 int git_diff_heuristic_config(const char *var, const char *value, void *cb)
 226 {
 227         if (!strcmp(var, "diff.indentheuristic"))
 228                 diff_indent_heuristic = git_config_bool(var, value);
 229         return 0;
 230 }
 231
 232 int git_diff_ui_config(const char *var, const char *value, void *cb)
 233 {
 234         if (!strcmp(var, "diff.color") || !strcmp(var, "color.diff")) {
 235                 diff_use_color_default = git_config_colorbool(var, value);
 236                 return 0;
 237         }
 238         if (!strcmp(var, "diff.context")) {
 239                 diff_context_default = git_config_int(var, value);
 240                 if (diff_context_default < 0)
 241                         return -1;
 242                 return 0;
 243         }
 244         if (!strcmp(var, "diff.interhunkcontext")) {
 245                 diff_interhunk_context_default = git_config_int(var, value);
 246                 if (diff_interhunk_context_default < 0)
 247                         return -1;
 248                 return 0;
 249         }
 250         if (!strcmp(var, "diff.renames")) {
 251                 diff_detect_rename_default = git_config_rename(var, value);
 252                 return 0;
 253         }
 254         if (!strcmp(var, "diff.autorefreshindex")) {
 255                 diff_auto_refresh_index = git_config_bool(var, value);
 256                 return 0;
 257         }
 258         if (!strcmp(var, "diff.mnemonicprefix")) {
 259                 diff_mnemonic_prefix = git_config_bool(var, value);
 260                 return 0;
 261         }
 262         if (!strcmp(var, "diff.noprefix")) {
 263                 diff_no_prefix = git_config_bool(var, value);
 264                 return 0;
 265         }
 266         if (!strcmp(var, "diff.statgraphwidth")) {
 267                 diff_stat_graph_width = git_config_int(var, value);
 268                 return 0;
 269         }
 270         if (!strcmp(var, "diff.external"))
 271                 return git_config_string(&external_diff_cmd_cfg, var, value);
 272         if (!strcmp(var, "diff.wordregex"))
 273                 return git_config_string(&diff_word_regex_cfg, var, value);
 274         if (!strcmp(var, "diff.orderfile"))
 275                 return git_config_pathname(&diff_order_file_cfg, var, value);
 276
 277         if (!strcmp(var, "diff.ignoresubmodules"))
 278                 handle_ignore_submodules_arg(&default_diff_options, value);
 279
 280         if (!strcmp(var, "diff.submodule")) {
 281                 if (parse_submodule_params(&default_diff_options, value))
 282                         warning(_("Unknown value for 'diff.submodule' config variable: '%s'"),
 283                                 value);
 284                 return 0;
 285         }
 286
 287         if (!strcmp(var, "diff.algorithm")) {
 288                 diff_algorithm = parse_algorithm_value(value);
 289                 if (diff_algorithm < 0)
 290                         return -1;
 291                 return 0;
 292         }
 293
 294         if (!strcmp(var, "diff.wserrorhighlight")) {
 295                 int val = parse_ws_error_highlight(value);
 296                 if (val < 0)
 297                         return -1;
 298                 ws_error_highlight_default = val;
 299                 return 0;
 300         }
 301
 302         if (git_color_config(var, value, cb) < 0)
 303                 return -1;
 304
 305         return git_diff_basic_config(var, value, cb);
 306 }
 307
 308 int git_diff_basic_config(const char *var, const char *value, void *cb)
 309 {
 310         const char *name;
 311
 312         if (!strcmp(var, "diff.renamelimit")) {
 313                 diff_rename_limit_default = git_config_int(var, value);
 314                 return 0;
 315         }
 316
 317         if (userdiff_config(var, value) < 0)
 318                 return -1;
 319
 320         if (skip_prefix(var, "diff.color.", &name) ||
 321             skip_prefix(var, "color.diff.", &name)) {
 322                 int slot = parse_diff_color_slot(name);
 323                 if (slot < 0)
 324                         return 0;
 325                 if (!value)
 326                         return config_error_nonbool(var);
 327                 return color_parse(value, diff_colors[slot]);
 328         }
 329
 330         /* like GNU diff's --suppress-blank-empty option  */
 331         if (!strcmp(var, "diff.suppressblankempty") ||
 332                         /* for backwards compatibility */
 333                         !strcmp(var, "diff.suppress-blank-empty")) {
 334                 diff_suppress_blank_empty = git_config_bool(var, value);
 335                 return 0;
 336         }
 337
 338         if (!strcmp(var, "diff.dirstat")) {
 339                 struct strbuf errmsg = STRBUF_INIT;
 340                 default_diff_options.dirstat_permille = diff_dirstat_permille_default;
 341                 if (parse_dirstat_params(&default_diff_options, value, &errmsg))
 342                         warning(_("Found errors in 'diff.dirstat' config variable:\n%s"),
 343                                 errmsg.buf);
 344                 strbuf_release(&errmsg);
 345                 diff_dirstat_permille_default = default_diff_options.dirstat_permille;
 346                 return 0;
 347         }
 348
 349         if (starts_with(var, "submodule."))
 350                 return parse_submodule_config_option(var, value);
 351
 352         if (git_diff_heuristic_config(var, value, cb) < 0)
 353                 return -1;
 354
 355         return git_default_config(var, value, cb);
 356 }
 357
 358 static char *quote_two(const char *one, const char *two)
 359 {
 360         int need_one = quote_c_style(one, NULL, NULL, 1);
 361         int need_two = quote_c_style(two, NULL, NULL, 1);
 362         struct strbuf res = STRBUF_INIT;
 363
 364         if (need_one + need_two) {
 365                 strbuf_addch(&res, '"');
 366                 quote_c_style(one, &res, NULL, 1);
 367                 quote_c_style(two, &res, NULL, 1);
 368                 strbuf_addch(&res, '"');
 369         } else {
 370                 strbuf_addstr(&res, one);
 371                 strbuf_addstr(&res, two);
 372         }
 373         return strbuf_detach(&res, NULL);
 374 }
 375
 376 static const char *external_diff(void)
 377 {
 378         static const char *external_diff_cmd = NULL;
 379         static int done_preparing = 0;
 380
 381         if (done_preparing)
 382                 return external_diff_cmd;
 383         external_diff_cmd = getenv("GIT_EXTERNAL_DIFF");
 384         if (!external_diff_cmd)
 385                 external_diff_cmd = external_diff_cmd_cfg;
 386         done_preparing = 1;
 387         return external_diff_cmd;
 388 }
 389
 390 /*
 391  * Keep track of files used for diffing. Sometimes such an entry
 392  * refers to a temporary file, sometimes to an existing file, and
 393  * sometimes to "/dev/null".
 394  */
 395 static struct diff_tempfile {
 396         /*
 397          * filename external diff should read from, or NULL if this
 398          * entry is currently not in use:
 399          */
 400         const char *name;
 401
 402         char hex[GIT_MAX_HEXSZ + 1];
 403         char mode[10];
 404
 405         /*
 406          * If this diff_tempfile instance refers to a temporary file,
 407          * this tempfile object is used to manage its lifetime.
 408          */
 409         struct tempfile tempfile;
 410 } diff_temp[2];
 411
 412 typedef unsigned long (*sane_truncate_fn)(char *line, unsigned long len);
 413
 414 struct emit_callback {
 415         int color_diff;
 416         unsigned ws_rule;
 417         int blank_at_eof_in_preimage;
 418         int blank_at_eof_in_postimage;
 419         int lno_in_preimage;
 420         int lno_in_postimage;
 421         sane_truncate_fn truncate;
 422         const char **label_path;
 423         struct diff_words_data *diff_words;
 424         struct diff_options *opt;
 425         struct strbuf *header;
 426 };
 427
 428 static int count_lines(const char *data, int size)
 429 {
 430         int count, ch, completely_empty = 1, nl_just_seen = 0;
 431         count = 0;
 432         while (0 < size--) {
 433                 ch = *data++;
 434                 if (ch == '\n') {
 435                         count++;
 436                         nl_just_seen = 1;
 437                         completely_empty = 0;
 438                 }
 439                 else {
 440                         nl_just_seen = 0;
 441                         completely_empty = 0;
 442                 }
 443         }
 444         if (completely_empty)
 445                 return 0;
 446         if (!nl_just_seen)
 447                 count++; /* no trailing newline */
 448         return count;
 449 }
 450
 451 static int fill_mmfile(mmfile_t *mf, struct diff_filespec *one)
 452 {
 453         if (!DIFF_FILE_VALID(one)) {
 454                 mf->ptr = (char *)""; /* does not matter */
 455                 mf->size = 0;
 456                 return 0;
 457         }
 458         else if (diff_populate_filespec(one, 0))
 459                 return -1;
 460
 461         mf->ptr = one->data;
 462         mf->size = one->size;
 463         return 0;
 464 }
 465
 466 /* like fill_mmfile, but only for size, so we can avoid retrieving blob */
 467 static unsigned long diff_filespec_size(struct diff_filespec *one)
 468 {
 469         if (!DIFF_FILE_VALID(one))
 470                 return 0;
 471         diff_populate_filespec(one, CHECK_SIZE_ONLY);
 472         return one->size;
 473 }
 474
 475 static int count_trailing_blank(mmfile_t *mf, unsigned ws_rule)
 476 {
 477         char *ptr = mf->ptr;
 478         long size = mf->size;
 479         int cnt = 0;
 480
 481         if (!size)
 482                 return cnt;
 483         ptr += size - 1; /* pointing at the very end */
 484         if (*ptr != '\n')
 485                 ; /* incomplete line */
 486         else
 487                 ptr--; /* skip the last LF */
 488         while (mf->ptr < ptr) {
 489                 char *prev_eol;
 490                 for (prev_eol = ptr; mf->ptr <= prev_eol; prev_eol--)
 491                         if (*prev_eol == '\n')
 492                                 break;
 493                 if (!ws_blank_line(prev_eol + 1, ptr - prev_eol, ws_rule))
 494                         break;
 495                 cnt++;
 496                 ptr = prev_eol - 1;
 497         }
 498         return cnt;
 499 }
 500
 501 static void check_blank_at_eof(mmfile_t *mf1, mmfile_t *mf2,
 502                                struct emit_callback *ecbdata)
 503 {
 504         int l1, l2, at;
 505         unsigned ws_rule = ecbdata->ws_rule;
 506         l1 = count_trailing_blank(mf1, ws_rule);
 507         l2 = count_trailing_blank(mf2, ws_rule);
 508         if (l2 <= l1) {
 509                 ecbdata->blank_at_eof_in_preimage = 0;
 510                 ecbdata->blank_at_eof_in_postimage = 0;
 511                 return;
 512         }
 513         at = count_lines(mf1->ptr, mf1->size);
 514         ecbdata->blank_at_eof_in_preimage = (at - l1) + 1;
 515
 516         at = count_lines(mf2->ptr, mf2->size);
 517         ecbdata->blank_at_eof_in_postimage = (at - l2) + 1;
 518 }
 519
 520 static void emit_line_0(struct diff_options *o, const char *set, const char *reset,
 521                         int first, const char *line, int len)
 522 {
 523         int has_trailing_newline, has_trailing_carriage_return;
 524         int nofirst;
 525         FILE *file = o->file;
 526
 527         fputs(diff_line_prefix(o), file);
 528
 529         if (len == 0) {
 530                 has_trailing_newline = (first == '\n');
 531                 has_trailing_carriage_return = (!has_trailing_newline &&
 532                                                 (first == '\r'));
 533                 nofirst = has_trailing_newline || has_trailing_carriage_return;
 534         } else {
 535                 has_trailing_newline = (len > 0 && line[len-1] == '\n');
 536                 if (has_trailing_newline)
 537                         len--;
 538                 has_trailing_carriage_return = (len > 0 && line[len-1] == '\r');
 539                 if (has_trailing_carriage_return)
 540                         len--;
 541                 nofirst = 0;
 542         }
 543
 544         if (len || !nofirst) {
 545                 fputs(set, file);
 546                 if (!nofirst)
 547                         fputc(first, file);
 548                 fwrite(line, len, 1, file);
 549                 fputs(reset, file);
 550         }
 551         if (has_trailing_carriage_return)
 552                 fputc('\r', file);
 553         if (has_trailing_newline)
 554                 fputc('\n', file);
 555 }
 556
 557 static void emit_line(struct diff_options *o, const char *set, const char *reset,
 558                       const char *line, int len)
 559 {
 560         emit_line_0(o, set, reset, line[0], line+1, len-1);
 561 }
 562
 563 enum diff_symbol {
 564         DIFF_SYMBOL_REWRITE_DIFF,
 565         DIFF_SYMBOL_BINARY_FILES,
 566         DIFF_SYMBOL_HEADER,
 567         DIFF_SYMBOL_FILEPAIR_PLUS,
 568         DIFF_SYMBOL_FILEPAIR_MINUS,
 569         DIFF_SYMBOL_WORDS_PORCELAIN,
 570         DIFF_SYMBOL_WORDS,
 571         DIFF_SYMBOL_CONTEXT,
 572         DIFF_SYMBOL_CONTEXT_INCOMPLETE,
 573         DIFF_SYMBOL_PLUS,
 574         DIFF_SYMBOL_MINUS,
 575         DIFF_SYMBOL_NO_LF_EOF,
 576         DIFF_SYMBOL_CONTEXT_FRAGINFO,
 577         DIFF_SYMBOL_CONTEXT_MARKER,
 578         DIFF_SYMBOL_SEPARATOR
 579 };
 580 /*
 581  * Flags for content lines:
 582  * 0..12 are whitespace rules
 583  * 13-15 are WSEH_NEW | WSEH_OLD | WSEH_CONTEXT
 584  * 16 is marking if the line is blank at EOF
 585  */
 586 #define DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF (1<<16)
 587 #define DIFF_SYMBOL_CONTENT_WS_MASK (WSEH_NEW | WSEH_OLD | WSEH_CONTEXT | WS_RULE_MASK)
 588
 589 static void emit_line_ws_markup(struct diff_options *o,
 590                                 const char *set, const char *reset,
 591                                 const char *line, int len, char sign,
 592                                 unsigned ws_rule, int blank_at_eof)
 593 {
 594         const char *ws = NULL;
 595
 596         if (o->ws_error_highlight & ws_rule) {
 597                 ws = diff_get_color_opt(o, DIFF_WHITESPACE);
 598                 if (!*ws)
 599                         ws = NULL;
 600         }
 601
 602         if (!ws)
 603                 emit_line_0(o, set, reset, sign, line, len);
 604         else if (blank_at_eof)
 605                 /* Blank line at EOF - paint '+' as well */
 606                 emit_line_0(o, ws, reset, sign, line, len);
 607         else {
 608                 /* Emit just the prefix, then the rest. */
 609                 emit_line_0(o, set, reset, sign, "", 0);
 610                 ws_check_emit(line, len, ws_rule,
 611                               o->file, set, reset, ws);
 612         }
 613 }
 614
 615 static void emit_diff_symbol(struct diff_options *o, enum diff_symbol s,
 616                              const char *line, int len, unsigned flags)
 617 {
 618         static const char *nneof = " No newline at end of file\n";
 619         const char *context, *reset, *set, *meta, *fraginfo;
 620         switch (s) {
 621         case DIFF_SYMBOL_NO_LF_EOF:
 622                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 623                 reset = diff_get_color_opt(o, DIFF_RESET);
 624                 putc('\n', o->file);
 625                 emit_line_0(o, context, reset, '\\',
 626                             nneof, strlen(nneof));
 627                 break;
 628         case DIFF_SYMBOL_CONTEXT_FRAGINFO:
 629                 emit_line(o, "", "", line, len);
 630                 break;
 631         case DIFF_SYMBOL_CONTEXT_INCOMPLETE:
 632         case DIFF_SYMBOL_CONTEXT_MARKER:
 633                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 634                 reset = diff_get_color_opt(o, DIFF_RESET);
 635                 emit_line(o, context, reset, line, len);
 636                 break;
 637         case DIFF_SYMBOL_SEPARATOR:
 638                 fprintf(o->file, "%s%c",
 639                         diff_line_prefix(o),
 640                         o->line_termination);
 641                 break;
 642         case DIFF_SYMBOL_CONTEXT:
 643                 set = diff_get_color_opt(o, DIFF_CONTEXT);
 644                 reset = diff_get_color_opt(o, DIFF_RESET);
 645                 emit_line_ws_markup(o, set, reset, line, len, ' ',
 646                                     flags & (DIFF_SYMBOL_CONTENT_WS_MASK), 0);
 647                 break;
 648         case DIFF_SYMBOL_PLUS:
 649                 set = diff_get_color_opt(o, DIFF_FILE_NEW);
 650                 reset = diff_get_color_opt(o, DIFF_RESET);
 651                 emit_line_ws_markup(o, set, reset, line, len, '+',
 652                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK,
 653                                     flags & DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF);
 654                 break;
 655         case DIFF_SYMBOL_MINUS:
 656                 set = diff_get_color_opt(o, DIFF_FILE_OLD);
 657                 reset = diff_get_color_opt(o, DIFF_RESET);
 658                 emit_line_ws_markup(o, set, reset, line, len, '-',
 659                                     flags & DIFF_SYMBOL_CONTENT_WS_MASK, 0);
 660                 break;
 661         case DIFF_SYMBOL_WORDS_PORCELAIN:
 662                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 663                 reset = diff_get_color_opt(o, DIFF_RESET);
 664                 emit_line(o, context, reset, line, len);
 665                 fputs("~\n", o->file);
 666                 break;
 667         case DIFF_SYMBOL_WORDS:
 668                 context = diff_get_color_opt(o, DIFF_CONTEXT);
 669                 reset = diff_get_color_opt(o, DIFF_RESET);
 670                 /*
 671                  * Skip the prefix character, if any.  With
 672                  * diff_suppress_blank_empty, there may be
 673                  * none.
 674                  */
 675                 if (line[0] != '\n') {
 676                         line++;
 677                         len--;
 678                 }
 679                 emit_line(o, context, reset, line, len);
 680                 break;
 681         case DIFF_SYMBOL_FILEPAIR_PLUS:
 682                 meta = diff_get_color_opt(o, DIFF_METAINFO);
 683                 reset = diff_get_color_opt(o, DIFF_RESET);
 684                 fprintf(o->file, "%s%s+++ %s%s%s\n", diff_line_prefix(o), meta,
 685                         line, reset,
 686                         strchr(line, ' ') ? "\t" : "");
 687                 break;
 688         case DIFF_SYMBOL_FILEPAIR_MINUS:
 689                 meta = diff_get_color_opt(o, DIFF_METAINFO);
 690                 reset = diff_get_color_opt(o, DIFF_RESET);
 691                 fprintf(o->file, "%s%s--- %s%s%s\n", diff_line_prefix(o), meta,
 692                         line, reset,
 693                         strchr(line, ' ') ? "\t" : "");
 694                 break;
 695         case DIFF_SYMBOL_BINARY_FILES:
 696         case DIFF_SYMBOL_HEADER:
 697                 fprintf(o->file, "%s", line);
 698                 break;
 699         case DIFF_SYMBOL_REWRITE_DIFF:
 700                 fraginfo = diff_get_color(o->use_color, DIFF_FRAGINFO);
 701                 reset = diff_get_color_opt(o, DIFF_RESET);
 702                 emit_line(o, fraginfo, reset, line, len);
 703                 break;
 704         default:
 705                 die("BUG: unknown diff symbol");
 706         }
 707 }
 708
 709 static int new_blank_line_at_eof(struct emit_callback *ecbdata, const char *line, int len)
 710 {
 711         if (!((ecbdata->ws_rule & WS_BLANK_AT_EOF) &&
 712               ecbdata->blank_at_eof_in_preimage &&
 713               ecbdata->blank_at_eof_in_postimage &&
 714               ecbdata->blank_at_eof_in_preimage <= ecbdata->lno_in_preimage &&
 715               ecbdata->blank_at_eof_in_postimage <= ecbdata->lno_in_postimage))
 716                 return 0;
 717         return ws_blank_line(line, len, ecbdata->ws_rule);
 718 }
 719
 720 static void emit_add_line(const char *reset,
 721                           struct emit_callback *ecbdata,
 722                           const char *line, int len)
 723 {
 724         unsigned flags = WSEH_NEW | ecbdata->ws_rule;
 725         if (new_blank_line_at_eof(ecbdata, line, len))
 726                 flags |= DIFF_SYMBOL_CONTENT_BLANK_LINE_EOF;
 727
 728         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_PLUS, line, len, flags);
 729 }
 730
 731 static void emit_del_line(const char *reset,
 732                           struct emit_callback *ecbdata,
 733                           const char *line, int len)
 734 {
 735         unsigned flags = WSEH_OLD | ecbdata->ws_rule;
 736         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_MINUS, line, len, flags);
 737 }
 738
 739 static void emit_context_line(const char *reset,
 740                               struct emit_callback *ecbdata,
 741                               const char *line, int len)
 742 {
 743         unsigned flags = WSEH_CONTEXT | ecbdata->ws_rule;
 744         emit_diff_symbol(ecbdata->opt, DIFF_SYMBOL_CONTEXT, line, len, flags);
 745 }
 746
 747 static void emit_hunk_header(struct emit_callback *ecbdata,
 748                              const char *line, int len)
 749 {
 750         const char *context = diff_get_color(ecbdata->color_diff, DIFF_CONTEXT);
 751         const char *frag = diff_get_color(ecbdata->color_diff, DIFF_FRAGINFO);
 752         const char *func = diff_get_color(ecbdata->color_diff, DIFF_FUNCINFO);
 753         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
 754         static const char atat[2] = { '@', '@' };
 755         const char *cp, *ep;
 756         struct strbuf msgbuf = STRBUF_INIT;
 757         int org_len = len;
 758         int i = 1;
 759
 760         /*
 761          * As a hunk header must begin with "@@ -<old>, +<new> @@",
 762          * it always is at least 10 bytes long.
 763          */
 764         if (len < 10 ||
 765             memcmp(line, atat, 2) ||
 766             !(ep = memmem(line + 2, len - 2, atat, 2))) {
 767                 emit_diff_symbol(ecbdata->opt,
 768                                  DIFF_SYMBOL_CONTEXT_MARKER, line, len, 0);
 769                 return;
 770         }
 771         ep += 2; /* skip over @@ */
 772
 773         /* The hunk header in fraginfo color */
 774         strbuf_addstr(&msgbuf, frag);
 775         strbuf_add(&msgbuf, line, ep - line);
 776         strbuf_addstr(&msgbuf, reset);
 777
 778         /*
 779          * trailing "\r\n"
 780          */
 781         for ( ; i < 3; i++)
 782                 if (line[len - i] == '\r' || line[len - i] == '\n')
 783                         len--;
 784
 785         /* blank before the func header */
 786         for (cp = ep; ep - line < len; ep++)
 787                 if (*ep != ' ' && *ep != '\t')
 788                         break;
 789         if (ep != cp) {
 790                 strbuf_addstr(&msgbuf, context);
 791                 strbuf_add(&msgbuf, cp, ep - cp);
 792                 strbuf_addstr(&msgbuf, reset);
 793         }
 794
 795         if (ep < line + len) {
 796                 strbuf_addstr(&msgbuf, func);
 797                 strbuf_add(&msgbuf, ep, line + len - ep);
 798                 strbuf_addstr(&msgbuf, reset);
 799         }
 800
 801         strbuf_add(&msgbuf, line + len, org_len - len);
 802         strbuf_complete_line(&msgbuf);
 803         emit_diff_symbol(ecbdata->opt,
 804                          DIFF_SYMBOL_CONTEXT_FRAGINFO, msgbuf.buf, msgbuf.len, 0);
 805         strbuf_release(&msgbuf);
 806 }
 807
 808 static struct diff_tempfile *claim_diff_tempfile(void) {
 809         int i;
 810         for (i = 0; i < ARRAY_SIZE(diff_temp); i++)
 811                 if (!diff_temp[i].name)
 812                         return diff_temp + i;
 813         die("BUG: diff is failing to clean up its tempfiles");
 814 }
 815
 816 static void remove_tempfile(void)
 817 {
 818         int i;
 819         for (i = 0; i < ARRAY_SIZE(diff_temp); i++) {
 820                 if (is_tempfile_active(&diff_temp[i].tempfile))
 821                         delete_tempfile(&diff_temp[i].tempfile);
 822                 diff_temp[i].name = NULL;
 823         }
 824 }
 825
 826 static void add_line_count(struct strbuf *out, int count)
 827 {
 828         switch (count) {
 829         case 0:
 830                 strbuf_addstr(out, "0,0");
 831                 break;
 832         case 1:
 833                 strbuf_addstr(out, "1");
 834                 break;
 835         default:
 836                 strbuf_addf(out, "1,%d", count);
 837                 break;
 838         }
 839 }
 840
 841 static void emit_rewrite_lines(struct emit_callback *ecb,
 842                                int prefix, const char *data, int size)
 843 {
 844         const char *endp = NULL;
 845         const char *reset = diff_get_color(ecb->color_diff, DIFF_RESET);
 846
 847         while (0 < size) {
 848                 int len;
 849
 850                 endp = memchr(data, '\n', size);
 851                 len = endp ? (endp - data + 1) : size;
 852                 if (prefix != '+') {
 853                         ecb->lno_in_preimage++;
 854                         emit_del_line(reset, ecb, data, len);
 855                 } else {
 856                         ecb->lno_in_postimage++;
 857                         emit_add_line(reset, ecb, data, len);
 858                 }
 859                 size -= len;
 860                 data += len;
 861         }
 862         if (!endp)
 863                 emit_diff_symbol(ecb->opt, DIFF_SYMBOL_NO_LF_EOF, NULL, 0, 0);
 864 }
 865
 866 static void emit_rewrite_diff(const char *name_a,
 867                               const char *name_b,
 868                               struct diff_filespec *one,
 869                               struct diff_filespec *two,
 870                               struct userdiff_driver *textconv_one,
 871                               struct userdiff_driver *textconv_two,
 872                               struct diff_options *o)
 873 {
 874         int lc_a, lc_b;
 875         static struct strbuf a_name = STRBUF_INIT, b_name = STRBUF_INIT;
 876         const char *a_prefix, *b_prefix;
 877         char *data_one, *data_two;
 878         size_t size_one, size_two;
 879         struct emit_callback ecbdata;
 880         struct strbuf out = STRBUF_INIT;
 881
 882         if (diff_mnemonic_prefix && DIFF_OPT_TST(o, REVERSE_DIFF)) {
 883                 a_prefix = o->b_prefix;
 884                 b_prefix = o->a_prefix;
 885         } else {
 886                 a_prefix = o->a_prefix;
 887                 b_prefix = o->b_prefix;
 888         }
 889
 890         name_a += (*name_a == '/');
 891         name_b += (*name_b == '/');
 892
 893         strbuf_reset(&a_name);
 894         strbuf_reset(&b_name);
 895         quote_two_c_style(&a_name, a_prefix, name_a, 0);
 896         quote_two_c_style(&b_name, b_prefix, name_b, 0);
 897
 898         size_one = fill_textconv(textconv_one, one, &data_one);
 899         size_two = fill_textconv(textconv_two, two, &data_two);
 900
 901         memset(&ecbdata, 0, sizeof(ecbdata));
 902         ecbdata.color_diff = want_color(o->use_color);
 903         ecbdata.ws_rule = whitespace_rule(name_b);
 904         ecbdata.opt = o;
 905         if (ecbdata.ws_rule & WS_BLANK_AT_EOF) {
 906                 mmfile_t mf1, mf2;
 907                 mf1.ptr = (char *)data_one;
 908                 mf2.ptr = (char *)data_two;
 909                 mf1.size = size_one;
 910                 mf2.size = size_two;
 911                 check_blank_at_eof(&mf1, &mf2, &ecbdata);
 912         }
 913         ecbdata.lno_in_preimage = 1;
 914         ecbdata.lno_in_postimage = 1;
 915
 916         lc_a = count_lines(data_one, size_one);
 917         lc_b = count_lines(data_two, size_two);
 918
 919         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
 920                          a_name.buf, a_name.len, 0);
 921         emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
 922                          b_name.buf, b_name.len, 0);
 923
 924         strbuf_addstr(&out, "@@ -");
 925         if (!o->irreversible_delete)
 926                 add_line_count(&out, lc_a);
 927         else
 928                 strbuf_addstr(&out, "?,?");
 929         strbuf_addstr(&out, " +");
 930         add_line_count(&out, lc_b);
 931         strbuf_addstr(&out, " @@\n");
 932         emit_diff_symbol(o, DIFF_SYMBOL_REWRITE_DIFF, out.buf, out.len, 0);
 933         strbuf_release(&out);
 934
 935         if (lc_a && !o->irreversible_delete)
 936                 emit_rewrite_lines(&ecbdata, '-', data_one, size_one);
 937         if (lc_b)
 938                 emit_rewrite_lines(&ecbdata, '+', data_two, size_two);
 939         if (textconv_one)
 940                 free((char *)data_one);
 941         if (textconv_two)
 942                 free((char *)data_two);
 943 }
 944
 945 struct diff_words_buffer {
 946         mmfile_t text;
 947         long alloc;
 948         struct diff_words_orig {
 949                 const char *begin, *end;
 950         } *orig;
 951         int orig_nr, orig_alloc;
 952 };
 953
 954 static void diff_words_append(char *line, unsigned long len,
 955                 struct diff_words_buffer *buffer)
 956 {
 957         ALLOC_GROW(buffer->text.ptr, buffer->text.size + len, buffer->alloc);
 958         line++;
 959         len--;
 960         memcpy(buffer->text.ptr + buffer->text.size, line, len);
 961         buffer->text.size += len;
 962         buffer->text.ptr[buffer->text.size] = '\0';
 963 }
 964
 965 struct diff_words_style_elem {
 966         const char *prefix;
 967         const char *suffix;
 968         const char *color; /* NULL; filled in by the setup code if
 969                             * color is enabled */
 970 };
 971
 972 struct diff_words_style {
 973         enum diff_words_type type;
 974         struct diff_words_style_elem new, old, ctx;
 975         const char *newline;
 976 };
 977
 978 static struct diff_words_style diff_words_styles[] = {
 979         { DIFF_WORDS_PORCELAIN, {"+", "\n"}, {"-", "\n"}, {" ", "\n"}, "~\n" },
 980         { DIFF_WORDS_PLAIN, {"{+", "+}"}, {"[-", "-]"}, {"", ""}, "\n" },
 981         { DIFF_WORDS_COLOR, {"", ""}, {"", ""}, {"", ""}, "\n" }
 982 };
 983
 984 struct diff_words_data {
 985         struct diff_words_buffer minus, plus;
 986         const char *current_plus;
 987         int last_minus;
 988         struct diff_options *opt;
 989         regex_t *word_regex;
 990         enum diff_words_type type;
 991         struct diff_words_style *style;
 992 };
 993
 994 static int fn_out_diff_words_write_helper(FILE *fp,
 995                                           struct diff_words_style_elem *st_el,
 996                                           const char *newline,
 997                                           size_t count, const char *buf,
 998                                           const char *line_prefix)
 999 {
1000         int print = 0;
1001
1002         while (count) {
1003                 char *p = memchr(buf, '\n', count);
1004                 if (print)
1005                         fputs(line_prefix, fp);
1006                 if (p != buf) {
1007                         if (st_el->color && fputs(st_el->color, fp) < 0)
1008                                 return -1;
1009                         if (fputs(st_el->prefix, fp) < 0 ||
1010                             fwrite(buf, p ? p - buf : count, 1, fp) != 1 ||
1011                             fputs(st_el->suffix, fp) < 0)
1012                                 return -1;
1013                         if (st_el->color && *st_el->color
1014                             && fputs(GIT_COLOR_RESET, fp) < 0)
1015                                 return -1;
1016                 }
1017                 if (!p)
1018                         return 0;
1019                 if (fputs(newline, fp) < 0)
1020                         return -1;
1021                 count -= p + 1 - buf;
1022                 buf = p + 1;
1023                 print = 1;
1024         }
1025         return 0;
1026 }
1027
1028 /*
1029  * '--color-words' algorithm can be described as:
1030  *
1031  *   1. collect the minus/plus lines of a diff hunk, divided into
1032  *      minus-lines and plus-lines;
1033  *
1034  *   2. break both minus-lines and plus-lines into words and
1035  *      place them into two mmfile_t with one word for each line;
1036  *
1037  *   3. use xdiff to run diff on the two mmfile_t to get the words level diff;
1038  *
1039  * And for the common parts of the both file, we output the plus side text.
1040  * diff_words->current_plus is used to trace the current position of the plus file
1041  * which printed. diff_words->last_minus is used to trace the last minus word
1042  * printed.
1043  *
1044  * For '--graph' to work with '--color-words', we need to output the graph prefix
1045  * on each line of color words output. Generally, there are two conditions on
1046  * which we should output the prefix.
1047  *
1048  *   1. diff_words->last_minus == 0 &&
1049  *      diff_words->current_plus == diff_words->plus.text.ptr
1050  *
1051  *      that is: the plus text must start as a new line, and if there is no minus
1052  *      word printed, a graph prefix must be printed.
1053  *
1054  *   2. diff_words->current_plus > diff_words->plus.text.ptr &&
1055  *      *(diff_words->current_plus - 1) == '\n'
1056  *
1057  *      that is: a graph prefix must be printed following a '\n'
1058  */
1059 static int color_words_output_graph_prefix(struct diff_words_data *diff_words)
1060 {
1061         if ((diff_words->last_minus == 0 &&
1062                 diff_words->current_plus == diff_words->plus.text.ptr) ||
1063                 (diff_words->current_plus > diff_words->plus.text.ptr &&
1064                 *(diff_words->current_plus - 1) == '\n')) {
1065                 return 1;
1066         } else {
1067                 return 0;
1068         }
1069 }
1070
1071 static void fn_out_diff_words_aux(void *priv, char *line, unsigned long len)
1072 {
1073         struct diff_words_data *diff_words = priv;
1074         struct diff_words_style *style = diff_words->style;
1075         int minus_first, minus_len, plus_first, plus_len;
1076         const char *minus_begin, *minus_end, *plus_begin, *plus_end;
1077         struct diff_options *opt = diff_words->opt;
1078         const char *line_prefix;
1079
1080         if (line[0] != '@' || parse_hunk_header(line, len,
1081                         &minus_first, &minus_len, &plus_first, &plus_len))
1082                 return;
1083
1084         assert(opt);
1085         line_prefix = diff_line_prefix(opt);
1086
1087         /* POSIX requires that first be decremented by one if len == 0... */
1088         if (minus_len) {
1089                 minus_begin = diff_words->minus.orig[minus_first].begin;
1090                 minus_end =
1091                         diff_words->minus.orig[minus_first + minus_len - 1].end;
1092         } else
1093                 minus_begin = minus_end =
1094                         diff_words->minus.orig[minus_first].end;
1095
1096         if (plus_len) {
1097                 plus_begin = diff_words->plus.orig[plus_first].begin;
1098                 plus_end = diff_words->plus.orig[plus_first + plus_len - 1].end;
1099         } else
1100                 plus_begin = plus_end = diff_words->plus.orig[plus_first].end;
1101
1102         if (color_words_output_graph_prefix(diff_words)) {
1103                 fputs(line_prefix, diff_words->opt->file);
1104         }
1105         if (diff_words->current_plus != plus_begin) {
1106                 fn_out_diff_words_write_helper(diff_words->opt->file,
1107                                 &style->ctx, style->newline,
1108                                 plus_begin - diff_words->current_plus,
1109                                 diff_words->current_plus, line_prefix);
1110                 if (*(plus_begin - 1) == '\n')
1111                         fputs(line_prefix, diff_words->opt->file);
1112         }
1113         if (minus_begin != minus_end) {
1114                 fn_out_diff_words_write_helper(diff_words->opt->file,
1115                                 &style->old, style->newline,
1116                                 minus_end - minus_begin, minus_begin,
1117                                 line_prefix);
1118         }
1119         if (plus_begin != plus_end) {
1120                 fn_out_diff_words_write_helper(diff_words->opt->file,
1121                                 &style->new, style->newline,
1122                                 plus_end - plus_begin, plus_begin,
1123                                 line_prefix);
1124         }
1125
1126         diff_words->current_plus = plus_end;
1127         diff_words->last_minus = minus_first;
1128 }
1129
1130 /* This function starts looking at *begin, and returns 0 iff a word was found. */
1131 static int find_word_boundaries(mmfile_t *buffer, regex_t *word_regex,
1132                 int *begin, int *end)
1133 {
1134         if (word_regex && *begin < buffer->size) {
1135                 regmatch_t match[1];
1136                 if (!regexec_buf(word_regex, buffer->ptr + *begin,
1137                                  buffer->size - *begin, 1, match, 0)) {
1138                         char *p = memchr(buffer->ptr + *begin + match[0].rm_so,
1139                                         '\n', match[0].rm_eo - match[0].rm_so);
1140                         *end = p ? p - buffer->ptr : match[0].rm_eo + *begin;
1141                         *begin += match[0].rm_so;
1142                         return *begin >= *end;
1143                 }
1144                 return -1;
1145         }
1146
1147         /* find the next word */
1148         while (*begin < buffer->size && isspace(buffer->ptr[*begin]))
1149                 (*begin)++;
1150         if (*begin >= buffer->size)
1151                 return -1;
1152
1153         /* find the end of the word */
1154         *end = *begin + 1;
1155         while (*end < buffer->size && !isspace(buffer->ptr[*end]))
1156                 (*end)++;
1157
1158         return 0;
1159 }
1160
1161 /*
1162  * This function splits the words in buffer->text, stores the list with
1163  * newline separator into out, and saves the offsets of the original words
1164  * in buffer->orig.
1165  */
1166 static void diff_words_fill(struct diff_words_buffer *buffer, mmfile_t *out,
1167                 regex_t *word_regex)
1168 {
1169         int i, j;
1170         long alloc = 0;
1171
1172         out->size = 0;
1173         out->ptr = NULL;
1174
1175         /* fake an empty "0th" word */
1176         ALLOC_GROW(buffer->orig, 1, buffer->orig_alloc);
1177         buffer->orig[0].begin = buffer->orig[0].end = buffer->text.ptr;
1178         buffer->orig_nr = 1;
1179
1180         for (i = 0; i < buffer->text.size; i++) {
1181                 if (find_word_boundaries(&buffer->text, word_regex, &i, &j))
1182                         return;
1183
1184                 /* store original boundaries */
1185                 ALLOC_GROW(buffer->orig, buffer->orig_nr + 1,
1186                                 buffer->orig_alloc);
1187                 buffer->orig[buffer->orig_nr].begin = buffer->text.ptr + i;
1188                 buffer->orig[buffer->orig_nr].end = buffer->text.ptr + j;
1189                 buffer->orig_nr++;
1190
1191                 /* store one word */
1192                 ALLOC_GROW(out->ptr, out->size + j - i + 1, alloc);
1193                 memcpy(out->ptr + out->size, buffer->text.ptr + i, j - i);
1194                 out->ptr[out->size + j - i] = '\n';
1195                 out->size += j - i + 1;
1196
1197                 i = j - 1;
1198         }
1199 }
1200
1201 /* this executes the word diff on the accumulated buffers */
1202 static void diff_words_show(struct diff_words_data *diff_words)
1203 {
1204         xpparam_t xpp;
1205         xdemitconf_t xecfg;
1206         mmfile_t minus, plus;
1207         struct diff_words_style *style = diff_words->style;
1208
1209         struct diff_options *opt = diff_words->opt;
1210         const char *line_prefix;
1211
1212         assert(opt);
1213         line_prefix = diff_line_prefix(opt);
1214
1215         /* special case: only removal */
1216         if (!diff_words->plus.text.size) {
1217                 fputs(line_prefix, diff_words->opt->file);
1218                 fn_out_diff_words_write_helper(diff_words->opt->file,
1219                         &style->old, style->newline,
1220                         diff_words->minus.text.size,
1221                         diff_words->minus.text.ptr, line_prefix);
1222                 diff_words->minus.text.size = 0;
1223                 return;
1224         }
1225
1226         diff_words->current_plus = diff_words->plus.text.ptr;
1227         diff_words->last_minus = 0;
1228
1229         memset(&xpp, 0, sizeof(xpp));
1230         memset(&xecfg, 0, sizeof(xecfg));
1231         diff_words_fill(&diff_words->minus, &minus, diff_words->word_regex);
1232         diff_words_fill(&diff_words->plus, &plus, diff_words->word_regex);
1233         xpp.flags = 0;
1234         /* as only the hunk header will be parsed, we need a 0-context */
1235         xecfg.ctxlen = 0;
1236         if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
1237                           &xpp, &xecfg))
1238                 die("unable to generate word diff");
1239         free(minus.ptr);
1240         free(plus.ptr);
1241         if (diff_words->current_plus != diff_words->plus.text.ptr +
1242                         diff_words->plus.text.size) {
1243                 if (color_words_output_graph_prefix(diff_words))
1244                         fputs(line_prefix, diff_words->opt->file);
1245                 fn_out_diff_words_write_helper(diff_words->opt->file,
1246                         &style->ctx, style->newline,
1247                         diff_words->plus.text.ptr + diff_words->plus.text.size
1248                         - diff_words->current_plus, diff_words->current_plus,
1249                         line_prefix);
1250         }
1251         diff_words->minus.text.size = diff_words->plus.text.size = 0;
1252 }
1253
1254 /* In "color-words" mode, show word-diff of words accumulated in the buffer */
1255 static void diff_words_flush(struct emit_callback *ecbdata)
1256 {
1257         if (ecbdata->diff_words->minus.text.size ||
1258             ecbdata->diff_words->plus.text.size)
1259                 diff_words_show(ecbdata->diff_words);
1260 }
1261
1262 static void diff_filespec_load_driver(struct diff_filespec *one)
1263 {
1264         /* Use already-loaded driver */
1265         if (one->driver)
1266                 return;
1267
1268         if (S_ISREG(one->mode))
1269                 one->driver = userdiff_find_by_path(one->path);
1270
1271         /* Fallback to default settings */
1272         if (!one->driver)
1273                 one->driver = userdiff_find_by_name("default");
1274 }
1275
1276 static const char *userdiff_word_regex(struct diff_filespec *one)
1277 {
1278         diff_filespec_load_driver(one);
1279         return one->driver->word_regex;
1280 }
1281
1282 static void init_diff_words_data(struct emit_callback *ecbdata,
1283                                  struct diff_options *orig_opts,
1284                                  struct diff_filespec *one,
1285                                  struct diff_filespec *two)
1286 {
1287         int i;
1288         struct diff_options *o = xmalloc(sizeof(struct diff_options));
1289         memcpy(o, orig_opts, sizeof(struct diff_options));
1290
1291         ecbdata->diff_words =
1292                 xcalloc(1, sizeof(struct diff_words_data));
1293         ecbdata->diff_words->type = o->word_diff;
1294         ecbdata->diff_words->opt = o;
1295         if (!o->word_regex)
1296                 o->word_regex = userdiff_word_regex(one);
1297         if (!o->word_regex)
1298                 o->word_regex = userdiff_word_regex(two);
1299         if (!o->word_regex)
1300                 o->word_regex = diff_word_regex_cfg;
1301         if (o->word_regex) {
1302                 ecbdata->diff_words->word_regex = (regex_t *)
1303                         xmalloc(sizeof(regex_t));
1304                 if (regcomp(ecbdata->diff_words->word_regex,
1305                             o->word_regex,
1306                             REG_EXTENDED | REG_NEWLINE))
1307                         die ("Invalid regular expression: %s",
1308                              o->word_regex);
1309         }
1310         for (i = 0; i < ARRAY_SIZE(diff_words_styles); i++) {
1311                 if (o->word_diff == diff_words_styles[i].type) {
1312                         ecbdata->diff_words->style =
1313                                 &diff_words_styles[i];
1314                         break;
1315                 }
1316         }
1317         if (want_color(o->use_color)) {
1318                 struct diff_words_style *st = ecbdata->diff_words->style;
1319                 st->old.color = diff_get_color_opt(o, DIFF_FILE_OLD);
1320                 st->new.color = diff_get_color_opt(o, DIFF_FILE_NEW);
1321                 st->ctx.color = diff_get_color_opt(o, DIFF_CONTEXT);
1322         }
1323 }
1324
1325 static void free_diff_words_data(struct emit_callback *ecbdata)
1326 {
1327         if (ecbdata->diff_words) {
1328                 diff_words_flush(ecbdata);
1329                 free (ecbdata->diff_words->opt);
1330                 free (ecbdata->diff_words->minus.text.ptr);
1331                 free (ecbdata->diff_words->minus.orig);
1332                 free (ecbdata->diff_words->plus.text.ptr);
1333                 free (ecbdata->diff_words->plus.orig);
1334                 if (ecbdata->diff_words->word_regex) {
1335                         regfree(ecbdata->diff_words->word_regex);
1336                         free(ecbdata->diff_words->word_regex);
1337                 }
1338                 FREE_AND_NULL(ecbdata->diff_words);
1339         }
1340 }
1341
1342 const char *diff_get_color(int diff_use_color, enum color_diff ix)
1343 {
1344         if (want_color(diff_use_color))
1345                 return diff_colors[ix];
1346         return "";
1347 }
1348
1349 const char *diff_line_prefix(struct diff_options *opt)
1350 {
1351         struct strbuf *msgbuf;
1352         if (!opt->output_prefix)
1353                 return "";
1354
1355         msgbuf = opt->output_prefix(opt, opt->output_prefix_data);
1356         return msgbuf->buf;
1357 }
1358
1359 static unsigned long sane_truncate_line(struct emit_callback *ecb, char *line, unsigned long len)
1360 {
1361         const char *cp;
1362         unsigned long allot;
1363         size_t l = len;
1364
1365         if (ecb->truncate)
1366                 return ecb->truncate(line, len);
1367         cp = line;
1368         allot = l;
1369         while (0 < l) {
1370                 (void) utf8_width(&cp, &l);
1371                 if (!cp)
1372                         break; /* truncated in the middle? */
1373         }
1374         return allot - l;
1375 }
1376
1377 static void find_lno(const char *line, struct emit_callback *ecbdata)
1378 {
1379         const char *p;
1380         ecbdata->lno_in_preimage = 0;
1381         ecbdata->lno_in_postimage = 0;
1382         p = strchr(line, '-');
1383         if (!p)
1384                 return; /* cannot happen */
1385         ecbdata->lno_in_preimage = strtol(p + 1, NULL, 10);
1386         p = strchr(p, '+');
1387         if (!p)
1388                 return; /* cannot happen */
1389         ecbdata->lno_in_postimage = strtol(p + 1, NULL, 10);
1390 }
1391
1392 static void fn_out_consume(void *priv, char *line, unsigned long len)
1393 {
1394         struct emit_callback *ecbdata = priv;
1395         const char *reset = diff_get_color(ecbdata->color_diff, DIFF_RESET);
1396         struct diff_options *o = ecbdata->opt;
1397
1398         o->found_changes = 1;
1399
1400         if (ecbdata->header) {
1401                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
1402                                  ecbdata->header->buf, ecbdata->header->len, 0);
1403                 strbuf_reset(ecbdata->header);
1404                 ecbdata->header = NULL;
1405         }
1406
1407         if (ecbdata->label_path[0]) {
1408                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_MINUS,
1409                                  ecbdata->label_path[0],
1410                                  strlen(ecbdata->label_path[0]), 0);
1411                 emit_diff_symbol(o, DIFF_SYMBOL_FILEPAIR_PLUS,
1412                                  ecbdata->label_path[1],
1413                                  strlen(ecbdata->label_path[1]), 0);
1414                 ecbdata->label_path[0] = ecbdata->label_path[1] = NULL;
1415         }
1416
1417         if (diff_suppress_blank_empty
1418             && len == 2 && line[0] == ' ' && line[1] == '\n') {
1419                 line[0] = '\n';
1420                 len = 1;
1421         }
1422
1423         if (line[0] == '@') {
1424                 if (ecbdata->diff_words)
1425                         diff_words_flush(ecbdata);
1426                 len = sane_truncate_line(ecbdata, line, len);
1427                 find_lno(line, ecbdata);
1428                 emit_hunk_header(ecbdata, line, len);
1429                 return;
1430         }
1431
1432         if (ecbdata->diff_words) {
1433                 enum diff_symbol s =
1434                         ecbdata->diff_words->type == DIFF_WORDS_PORCELAIN ?
1435                         DIFF_SYMBOL_WORDS_PORCELAIN : DIFF_SYMBOL_WORDS;
1436                 if (line[0] == '-') {
1437                         diff_words_append(line, len,
1438                                           &ecbdata->diff_words->minus);
1439                         return;
1440                 } else if (line[0] == '+') {
1441                         diff_words_append(line, len,
1442                                           &ecbdata->diff_words->plus);
1443                         return;
1444                 } else if (starts_with(line, "\\ ")) {
1445                         /*
1446                          * Eat the "no newline at eof" marker as if we
1447                          * saw a "+" or "-" line with nothing on it,
1448                          * and return without diff_words_flush() to
1449                          * defer processing. If this is the end of
1450                          * preimage, more "+" lines may come after it.
1451                          */
1452                         return;
1453                 }
1454                 diff_words_flush(ecbdata);
1455                 emit_diff_symbol(o, s, line, len, 0);
1456                 return;
1457         }
1458
1459         switch (line[0]) {
1460         case '+':
1461                 ecbdata->lno_in_postimage++;
1462                 emit_add_line(reset, ecbdata, line + 1, len - 1);
1463                 break;
1464         case '-':
1465                 ecbdata->lno_in_preimage++;
1466                 emit_del_line(reset, ecbdata, line + 1, len - 1);
1467                 break;
1468         case ' ':
1469                 ecbdata->lno_in_postimage++;
1470                 ecbdata->lno_in_preimage++;
1471                 emit_context_line(reset, ecbdata, line + 1, len - 1);
1472                 break;
1473         default:
1474                 /* incomplete line at the end */
1475                 ecbdata->lno_in_preimage++;
1476                 emit_diff_symbol(o, DIFF_SYMBOL_CONTEXT_INCOMPLETE,
1477                                  line, len, 0);
1478                 break;
1479         }
1480 }
1481
1482 static char *pprint_rename(const char *a, const char *b)
1483 {
1484         const char *old = a;
1485         const char *new = b;
1486         struct strbuf name = STRBUF_INIT;
1487         int pfx_length, sfx_length;
1488         int pfx_adjust_for_slash;
1489         int len_a = strlen(a);
1490         int len_b = strlen(b);
1491         int a_midlen, b_midlen;
1492         int qlen_a = quote_c_style(a, NULL, NULL, 0);
1493         int qlen_b = quote_c_style(b, NULL, NULL, 0);
1494
1495         if (qlen_a || qlen_b) {
1496                 quote_c_style(a, &name, NULL, 0);
1497                 strbuf_addstr(&name, " => ");
1498                 quote_c_style(b, &name, NULL, 0);
1499                 return strbuf_detach(&name, NULL);
1500         }
1501
1502         /* Find common prefix */
1503         pfx_length = 0;
1504         while (*old && *new && *old == *new) {
1505                 if (*old == '/')
1506                         pfx_length = old - a + 1;
1507                 old++;
1508                 new++;
1509         }
1510
1511         /* Find common suffix */
1512         old = a + len_a;
1513         new = b + len_b;
1514         sfx_length = 0;
1515         /*
1516          * If there is a common prefix, it must end in a slash.  In
1517          * that case we let this loop run 1 into the prefix to see the
1518          * same slash.
1519          *
1520          * If there is no common prefix, we cannot do this as it would
1521          * underrun the input strings.
1522          */
1523         pfx_adjust_for_slash = (pfx_length ? 1 : 0);
1524         while (a + pfx_length - pfx_adjust_for_slash <= old &&
1525                b + pfx_length - pfx_adjust_for_slash <= new &&
1526                *old == *new) {
1527                 if (*old == '/')
1528                         sfx_length = len_a - (old - a);
1529                 old--;
1530                 new--;
1531         }
1532
1533         /*
1534          * pfx{mid-a => mid-b}sfx
1535          * {pfx-a => pfx-b}sfx
1536          * pfx{sfx-a => sfx-b}
1537          * name-a => name-b
1538          */
1539         a_midlen = len_a - pfx_length - sfx_length;
1540         b_midlen = len_b - pfx_length - sfx_length;
1541         if (a_midlen < 0)
1542                 a_midlen = 0;
1543         if (b_midlen < 0)
1544                 b_midlen = 0;
1545
1546         strbuf_grow(&name, pfx_length + a_midlen + b_midlen + sfx_length + 7);
1547         if (pfx_length + sfx_length) {
1548                 strbuf_add(&name, a, pfx_length);
1549                 strbuf_addch(&name, '{');
1550         }
1551         strbuf_add(&name, a + pfx_length, a_midlen);
1552         strbuf_addstr(&name, " => ");
1553         strbuf_add(&name, b + pfx_length, b_midlen);
1554         if (pfx_length + sfx_length) {
1555                 strbuf_addch(&name, '}');
1556                 strbuf_add(&name, a + len_a - sfx_length, sfx_length);
1557         }
1558         return strbuf_detach(&name, NULL);
1559 }
1560
1561 struct diffstat_t {
1562         int nr;
1563         int alloc;
1564         struct diffstat_file {
1565                 char *from_name;
1566                 char *name;
1567                 char *print_name;
1568                 unsigned is_unmerged:1;
1569                 unsigned is_binary:1;
1570                 unsigned is_renamed:1;
1571                 unsigned is_interesting:1;
1572                 uintmax_t added, deleted;
1573         } **files;
1574 };
1575
1576 static struct diffstat_file *diffstat_add(struct diffstat_t *diffstat,
1577                                           const char *name_a,
1578                                           const char *name_b)
1579 {
1580         struct diffstat_file *x;
1581         x = xcalloc(1, sizeof(*x));
1582         ALLOC_GROW(diffstat->files, diffstat->nr + 1, diffstat->alloc);
1583         diffstat->files[diffstat->nr++] = x;
1584         if (name_b) {
1585                 x->from_name = xstrdup(name_a);
1586                 x->name = xstrdup(name_b);
1587                 x->is_renamed = 1;
1588         }
1589         else {
1590                 x->from_name = NULL;
1591                 x->name = xstrdup(name_a);
1592         }
1593         return x;
1594 }
1595
1596 static void diffstat_consume(void *priv, char *line, unsigned long len)
1597 {
1598         struct diffstat_t *diffstat = priv;
1599         struct diffstat_file *x = diffstat->files[diffstat->nr - 1];
1600
1601         if (line[0] == '+')
1602                 x->added++;
1603         else if (line[0] == '-')
1604                 x->deleted++;
1605 }
1606
1607 const char mime_boundary_leader[] = "------------";
1608
1609 static int scale_linear(int it, int width, int max_change)
1610 {
1611         if (!it)
1612                 return 0;
1613         /*
1614          * make sure that at least one '-' or '+' is printed if
1615          * there is any change to this path. The easiest way is to
1616          * scale linearly as if the alloted width is one column shorter
1617          * than it is, and then add 1 to the result.
1618          */
1619         return 1 + (it * (width - 1) / max_change);
1620 }
1621
1622 static void show_name(FILE *file,
1623                       const char *prefix, const char *name, int len)
1624 {
1625         fprintf(file, " %s%-*s |", prefix, len, name);
1626 }
1627
1628 static void show_graph(FILE *file, char ch, int cnt, const char *set, const char *reset)
1629 {
1630         if (cnt <= 0)
1631                 return;
1632         fprintf(file, "%s", set);
1633         while (cnt--)
1634                 putc(ch, file);
1635         fprintf(file, "%s", reset);
1636 }
1637
1638 static void fill_print_name(struct diffstat_file *file)
1639 {
1640         char *pname;
1641
1642         if (file->print_name)
1643                 return;
1644
1645         if (!file->is_renamed) {
1646                 struct strbuf buf = STRBUF_INIT;
1647                 if (quote_c_style(file->name, &buf, NULL, 0)) {
1648                         pname = strbuf_detach(&buf, NULL);
1649                 } else {
1650                         pname = file->name;
1651                         strbuf_release(&buf);
1652                 }
1653         } else {
1654                 pname = pprint_rename(file->from_name, file->name);
1655         }
1656         file->print_name = pname;
1657 }
1658
1659 int print_stat_summary(FILE *fp, int files, int insertions, int deletions)
1660 {
1661         struct strbuf sb = STRBUF_INIT;
1662         int ret;
1663
1664         if (!files) {
1665                 assert(insertions == 0 && deletions == 0);
1666                 return fprintf(fp, "%s\n", " 0 files changed");
1667         }
1668
1669         strbuf_addf(&sb,
1670                     (files == 1) ? " %d file changed" : " %d files changed",
1671                     files);
1672
1673         /*
1674          * For binary diff, the caller may want to print "x files
1675          * changed" with insertions == 0 && deletions == 0.
1676          *
1677          * Not omitting "0 insertions(+), 0 deletions(-)" in this case
1678          * is probably less confusing (i.e skip over "2 files changed
1679          * but nothing about added/removed lines? Is this a bug in Git?").
1680          */
1681         if (insertions || deletions == 0) {
1682                 strbuf_addf(&sb,
1683                             (insertions == 1) ? ", %d insertion(+)" : ", %d insertions(+)",
1684                             insertions);
1685         }
1686
1687         if (deletions || insertions == 0) {
1688                 strbuf_addf(&sb,
1689                             (deletions == 1) ? ", %d deletion(-)" : ", %d deletions(-)",
1690                             deletions);
1691         }
1692         strbuf_addch(&sb, '\n');
1693         ret = fputs(sb.buf, fp);
1694         strbuf_release(&sb);
1695         return ret;
1696 }
1697
1698 static void show_stats(struct diffstat_t *data, struct diff_options *options)
1699 {
1700         int i, len, add, del, adds = 0, dels = 0;
1701         uintmax_t max_change = 0, max_len = 0;
1702         int total_files = data->nr, count;
1703         int width, name_width, graph_width, number_width = 0, bin_width = 0;
1704         const char *reset, *add_c, *del_c;
1705         const char *line_prefix = "";
1706         int extra_shown = 0;
1707
1708         if (data->nr == 0)
1709                 return;
1710
1711         line_prefix = diff_line_prefix(options);
1712         count = options->stat_count ? options->stat_count : data->nr;
1713
1714         reset = diff_get_color_opt(options, DIFF_RESET);
1715         add_c = diff_get_color_opt(options, DIFF_FILE_NEW);
1716         del_c = diff_get_color_opt(options, DIFF_FILE_OLD);
1717
1718         /*
1719          * Find the longest filename and max number of changes
1720          */
1721         for (i = 0; (i < count) && (i < data->nr); i++) {
1722                 struct diffstat_file *file = data->files[i];
1723                 uintmax_t change = file->added + file->deleted;
1724
1725                 if (!file->is_interesting && (change == 0)) {
1726                         count++; /* not shown == room for one more */
1727                         continue;
1728                 }
1729                 fill_print_name(file);
1730                 len = strlen(file->print_name);
1731                 if (max_len < len)
1732                         max_len = len;
1733
1734                 if (file->is_unmerged) {
1735                         /* "Unmerged" is 8 characters */
1736                         bin_width = bin_width < 8 ? 8 : bin_width;
1737                         continue;
1738                 }
1739                 if (file->is_binary) {
1740                         /* "Bin XXX -> YYY bytes" */
1741                         int w = 14 + decimal_width(file->added)
1742                                 + decimal_width(file->deleted);
1743                         bin_width = bin_width < w ? w : bin_width;
1744                         /* Display change counts aligned with "Bin" */
1745                         number_width = 3;
1746                         continue;
1747                 }
1748
1749                 if (max_change < change)
1750                         max_change = change;
1751         }
1752         count = i; /* where we can stop scanning in data->files[] */
1753
1754         /*
1755          * We have width = stat_width or term_columns() columns total.
1756          * We want a maximum of min(max_len, stat_name_width) for the name part.
1757          * We want a maximum of min(max_change, stat_graph_width) for the +- part.
1758          * We also need 1 for " " and 4 + decimal_width(max_change)
1759          * for " | NNNN " and one the empty column at the end, altogether
1760          * 6 + decimal_width(max_change).
1761          *
1762          * If there's not enough space, we will use the smaller of
1763          * stat_name_width (if set) and 5/8*width for the filename,
1764          * and the rest for constant elements + graph part, but no more
1765          * than stat_graph_width for the graph part.
1766          * (5/8 gives 50 for filename and 30 for the constant parts + graph
1767          * for the standard terminal size).
1768          *
1769          * In other words: stat_width limits the maximum width, and
1770          * stat_name_width fixes the maximum width of the filename,
1771          * and is also used to divide available columns if there
1772          * aren't enough.
1773          *
1774          * Binary files are displayed with "Bin XXX -> YYY bytes"
1775          * instead of the change count and graph. This part is treated
1776          * similarly to the graph part, except that it is not
1777          * "scaled". If total width is too small to accommodate the
1778          * guaranteed minimum width of the filename part and the
1779          * separators and this message, this message will "overflow"
1780          * making the line longer than the maximum width.
1781          */
1782
1783         if (options->stat_width == -1)
1784                 width = term_columns() - strlen(line_prefix);
1785         else
1786                 width = options->stat_width ? options->stat_width : 80;
1787         number_width = decimal_width(max_change) > number_width ?
1788                 decimal_width(max_change) : number_width;
1789
1790         if (options->stat_graph_width == -1)
1791                 options->stat_graph_width = diff_stat_graph_width;
1792
1793         /*
1794          * Guarantee 3/8*16==6 for the graph part
1795          * and 5/8*16==10 for the filename part
1796          */
1797         if (width < 16 + 6 + number_width)
1798                 width = 16 + 6 + number_width;
1799
1800         /*
1801          * First assign sizes that are wanted, ignoring available width.
1802          * strlen("Bin XXX -> YYY bytes") == bin_width, and the part
1803          * starting from "XXX" should fit in graph_width.
1804          */
1805         graph_width = max_change + 4 > bin_width ? max_change : bin_width - 4;
1806         if (options->stat_graph_width &&
1807             options->stat_graph_width < graph_width)
1808                 graph_width = options->stat_graph_width;
1809
1810         name_width = (options->stat_name_width > 0 &&
1811                       options->stat_name_width < max_len) ?
1812                 options->stat_name_width : max_len;
1813
1814         /*
1815          * Adjust adjustable widths not to exceed maximum width
1816          */
1817         if (name_width + number_width + 6 + graph_width > width) {
1818                 if (graph_width > width * 3/8 - number_width - 6) {
1819                         graph_width = width * 3/8 - number_width - 6;
1820                         if (graph_width < 6)
1821                                 graph_width = 6;
1822                 }
1823
1824                 if (options->stat_graph_width &&
1825                     graph_width > options->stat_graph_width)
1826                         graph_width = options->stat_graph_width;
1827                 if (name_width > width - number_width - 6 - graph_width)
1828                         name_width = width - number_width - 6 - graph_width;
1829                 else
1830                         graph_width = width - number_width - 6 - name_width;
1831         }
1832
1833         /*
1834          * From here name_width is the width of the name area,
1835          * and graph_width is the width of the graph area.
1836          * max_change is used to scale graph properly.
1837          */
1838         for (i = 0; i < count; i++) {
1839                 const char *prefix = "";
1840                 struct diffstat_file *file = data->files[i];
1841                 char *name = file->print_name;
1842                 uintmax_t added = file->added;
1843                 uintmax_t deleted = file->deleted;
1844                 int name_len;
1845
1846                 if (!file->is_interesting && (added + deleted == 0))
1847                         continue;
1848
1849                 /*
1850                  * "scale" the filename
1851                  */
1852                 len = name_width;
1853                 name_len = strlen(name);
1854                 if (name_width < name_len) {
1855                         char *slash;
1856                         prefix = "...";
1857                         len -= 3;
1858                         name += name_len - len;
1859                         slash = strchr(name, '/');
1860                         if (slash)
1861                                 name = slash;
1862                 }
1863
1864                 if (file->is_binary) {
1865                         fprintf(options->file, "%s", line_prefix);
1866                         show_name(options->file, prefix, name, len);
1867                         fprintf(options->file, " %*s", number_width, "Bin");
1868                         if (!added && !deleted) {
1869                                 putc('\n', options->file);
1870                                 continue;
1871                         }
1872                         fprintf(options->file, " %s%"PRIuMAX"%s",
1873                                 del_c, deleted, reset);
1874                         fprintf(options->file, " -> ");
1875                         fprintf(options->file, "%s%"PRIuMAX"%s",
1876                                 add_c, added, reset);
1877                         fprintf(options->file, " bytes");
1878                         fprintf(options->file, "\n");
1879                         continue;
1880                 }
1881                 else if (file->is_unmerged) {
1882                         fprintf(options->file, "%s", line_prefix);
1883                         show_name(options->file, prefix, name, len);
1884                         fprintf(options->file, " Unmerged\n");
1885                         continue;
1886                 }
1887
1888                 /*
1889                  * scale the add/delete
1890                  */
1891                 add = added;
1892                 del = deleted;
1893
1894                 if (graph_width <= max_change) {
1895                         int total = scale_linear(add + del, graph_width, max_change);
1896                         if (total < 2 && add && del)
1897                                 /* width >= 2 due to the sanity check */
1898                                 total = 2;
1899                         if (add < del) {
1900                                 add = scale_linear(add, graph_width, max_change);
1901                                 del = total - add;
1902                         } else {
1903                                 del = scale_linear(del, graph_width, max_change);
1904                                 add = total - del;
1905                         }
1906                 }
1907                 fprintf(options->file, "%s", line_prefix);
1908                 show_name(options->file, prefix, name, len);
1909                 fprintf(options->file, " %*"PRIuMAX"%s",
1910                         number_width, added + deleted,
1911                         added + deleted ? " " : "");
1912                 show_graph(options->file, '+', add, add_c, reset);
1913                 show_graph(options->file, '-', del, del_c, reset);
1914                 fprintf(options->file, "\n");
1915         }
1916
1917         for (i = 0; i < data->nr; i++) {
1918                 struct diffstat_file *file = data->files[i];
1919                 uintmax_t added = file->added;
1920                 uintmax_t deleted = file->deleted;
1921
1922                 if (file->is_unmerged ||
1923                     (!file->is_interesting && (added + deleted == 0))) {
1924                         total_files--;
1925                         continue;
1926                 }
1927
1928                 if (!file->is_binary) {
1929                         adds += added;
1930                         dels += deleted;
1931                 }
1932                 if (i < count)
1933                         continue;
1934                 if (!extra_shown)
1935                         fprintf(options->file, "%s ...\n", line_prefix);
1936                 extra_shown = 1;
1937         }
1938         fprintf(options->file, "%s", line_prefix);
1939         print_stat_summary(options->file, total_files, adds, dels);
1940 }
1941
1942 static void show_shortstats(struct diffstat_t *data, struct diff_options *options)
1943 {
1944         int i, adds = 0, dels = 0, total_files = data->nr;
1945
1946         if (data->nr == 0)
1947                 return;
1948
1949         for (i = 0; i < data->nr; i++) {
1950                 int added = data->files[i]->added;
1951                 int deleted= data->files[i]->deleted;
1952
1953                 if (data->files[i]->is_unmerged ||
1954                     (!data->files[i]->is_interesting && (added + deleted == 0))) {
1955                         total_files--;
1956                 } else if (!data->files[i]->is_binary) { /* don't count bytes */
1957                         adds += added;
1958                         dels += deleted;
1959                 }
1960         }
1961         fprintf(options->file, "%s", diff_line_prefix(options));
1962         print_stat_summary(options->file, total_files, adds, dels);
1963 }
1964
1965 static void show_numstat(struct diffstat_t *data, struct diff_options *options)
1966 {
1967         int i;
1968
1969         if (data->nr == 0)
1970                 return;
1971
1972         for (i = 0; i < data->nr; i++) {
1973                 struct diffstat_file *file = data->files[i];
1974
1975                 fprintf(options->file, "%s", diff_line_prefix(options));
1976
1977                 if (file->is_binary)
1978                         fprintf(options->file, "-\t-\t");
1979                 else
1980                         fprintf(options->file,
1981                                 "%"PRIuMAX"\t%"PRIuMAX"\t",
1982                                 file->added, file->deleted);
1983                 if (options->line_termination) {
1984                         fill_print_name(file);
1985                         if (!file->is_renamed)
1986                                 write_name_quoted(file->name, options->file,
1987                                                   options->line_termination);
1988                         else {
1989                                 fputs(file->print_name, options->file);
1990                                 putc(options->line_termination, options->file);
1991                         }
1992                 } else {
1993                         if (file->is_renamed) {
1994                                 putc('\0', options->file);
1995                                 write_name_quoted(file->from_name, options->file, '\0');
1996                         }
1997                         write_name_quoted(file->name, options->file, '\0');
1998                 }
1999         }
2000 }
2001
2002 struct dirstat_file {
2003         const char *name;
2004         unsigned long changed;
2005 };
2006
2007 struct dirstat_dir {
2008         struct dirstat_file *files;
2009         int alloc, nr, permille, cumulative;
2010 };
2011
2012 static long gather_dirstat(struct diff_options *opt, struct dirstat_dir *dir,
2013                 unsigned long changed, const char *base, int baselen)
2014 {
2015         unsigned long this_dir = 0;
2016         unsigned int sources = 0;
2017         const char *line_prefix = diff_line_prefix(opt);
2018
2019         while (dir->nr) {
2020                 struct dirstat_file *f = dir->files;
2021                 int namelen = strlen(f->name);
2022                 unsigned long this;
2023                 char *slash;
2024
2025                 if (namelen < baselen)
2026                         break;
2027                 if (memcmp(f->name, base, baselen))
2028                         break;
2029                 slash = strchr(f->name + baselen, '/');
2030                 if (slash) {
2031                         int newbaselen = slash + 1 - f->name;
2032                         this = gather_dirstat(opt, dir, changed, f->name, newbaselen);
2033                         sources++;
2034                 } else {
2035                         this = f->changed;
2036                         dir->files++;
2037                         dir->nr--;
2038                         sources += 2;
2039                 }
2040                 this_dir += this;
2041         }
2042
2043         /*
2044          * We don't report dirstat's for
2045          *  - the top level
2046          *  - or cases where everything came from a single directory
2047          *    under this directory (sources == 1).
2048          */
2049         if (baselen && sources != 1) {
2050                 if (this_dir) {
2051                         int permille = this_dir * 1000 / changed;
2052                         if (permille >= dir->permille) {
2053                                 fprintf(opt->file, "%s%4d.%01d%% %.*s\n", line_prefix,
2054                                         permille / 10, permille % 10, baselen, base);
2055                                 if (!dir->cumulative)
2056                                         return 0;
2057                         }
2058                 }
2059         }
2060         return this_dir;
2061 }
2062
2063 static int dirstat_compare(const void *_a, const void *_b)
2064 {
2065         const struct dirstat_file *a = _a;
2066         const struct dirstat_file *b = _b;
2067         return strcmp(a->name, b->name);
2068 }
2069
2070 static void show_dirstat(struct diff_options *options)
2071 {
2072         int i;
2073         unsigned long changed;
2074         struct dirstat_dir dir;
2075         struct diff_queue_struct *q = &diff_queued_diff;
2076
2077         dir.files = NULL;
2078         dir.alloc = 0;
2079         dir.nr = 0;
2080         dir.permille = options->dirstat_permille;
2081         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2082
2083         changed = 0;
2084         for (i = 0; i < q->nr; i++) {
2085                 struct diff_filepair *p = q->queue[i];
2086                 const char *name;
2087                 unsigned long copied, added, damage;
2088                 int content_changed;
2089
2090                 name = p->two->path ? p->two->path : p->one->path;
2091
2092                 if (p->one->oid_valid && p->two->oid_valid)
2093                         content_changed = oidcmp(&p->one->oid, &p->two->oid);
2094                 else
2095                         content_changed = 1;
2096
2097                 if (!content_changed) {
2098                         /*
2099                          * The SHA1 has not changed, so pre-/post-content is
2100                          * identical. We can therefore skip looking at the
2101                          * file contents altogether.
2102                          */
2103                         damage = 0;
2104                         goto found_damage;
2105                 }
2106
2107                 if (DIFF_OPT_TST(options, DIRSTAT_BY_FILE)) {
2108                         /*
2109                          * In --dirstat-by-file mode, we don't really need to
2110                          * look at the actual file contents at all.
2111                          * The fact that the SHA1 changed is enough for us to
2112                          * add this file to the list of results
2113                          * (with each file contributing equal damage).
2114                          */
2115                         damage = 1;
2116                         goto found_damage;
2117                 }
2118
2119                 if (DIFF_FILE_VALID(p->one) && DIFF_FILE_VALID(p->two)) {
2120                         diff_populate_filespec(p->one, 0);
2121                         diff_populate_filespec(p->two, 0);
2122                         diffcore_count_changes(p->one, p->two, NULL, NULL,
2123                                                &copied, &added);
2124                         diff_free_filespec_data(p->one);
2125                         diff_free_filespec_data(p->two);
2126                 } else if (DIFF_FILE_VALID(p->one)) {
2127                         diff_populate_filespec(p->one, CHECK_SIZE_ONLY);
2128                         copied = added = 0;
2129                         diff_free_filespec_data(p->one);
2130                 } else if (DIFF_FILE_VALID(p->two)) {
2131                         diff_populate_filespec(p->two, CHECK_SIZE_ONLY);
2132                         copied = 0;
2133                         added = p->two->size;
2134                         diff_free_filespec_data(p->two);
2135                 } else
2136                         continue;
2137
2138                 /*
2139                  * Original minus copied is the removed material,
2140                  * added is the new material.  They are both damages
2141                  * made to the preimage.
2142                  * If the resulting damage is zero, we know that
2143                  * diffcore_count_changes() considers the two entries to
2144                  * be identical, but since content_changed is true, we
2145                  * know that there must have been _some_ kind of change,
2146                  * so we force all entries to have damage > 0.
2147                  */
2148                 damage = (p->one->size - copied) + added;
2149                 if (!damage)
2150                         damage = 1;
2151
2152 found_damage:
2153                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2154                 dir.files[dir.nr].name = name;
2155                 dir.files[dir.nr].changed = damage;
2156                 changed += damage;
2157                 dir.nr++;
2158         }
2159
2160         /* This can happen even with many files, if everything was renames */
2161         if (!changed)
2162                 return;
2163
2164         /* Show all directories with more than x% of the changes */
2165         QSORT(dir.files, dir.nr, dirstat_compare);
2166         gather_dirstat(options, &dir, changed, "", 0);
2167 }
2168
2169 static void show_dirstat_by_line(struct diffstat_t *data, struct diff_options *options)
2170 {
2171         int i;
2172         unsigned long changed;
2173         struct dirstat_dir dir;
2174
2175         if (data->nr == 0)
2176                 return;
2177
2178         dir.files = NULL;
2179         dir.alloc = 0;
2180         dir.nr = 0;
2181         dir.permille = options->dirstat_permille;
2182         dir.cumulative = DIFF_OPT_TST(options, DIRSTAT_CUMULATIVE);
2183
2184         changed = 0;
2185         for (i = 0; i < data->nr; i++) {
2186                 struct diffstat_file *file = data->files[i];
2187                 unsigned long damage = file->added + file->deleted;
2188                 if (file->is_binary)
2189                         /*
2190                          * binary files counts bytes, not lines. Must find some
2191                          * way to normalize binary bytes vs. textual lines.
2192                          * The following heuristic assumes that there are 64
2193                          * bytes per "line".
2194                          * This is stupid and ugly, but very cheap...
2195                          */
2196                         damage = (damage + 63) / 64;
2197                 ALLOC_GROW(dir.files, dir.nr + 1, dir.alloc);
2198                 dir.files[dir.nr].name = file->name;
2199                 dir.files[dir.nr].changed = damage;
2200                 changed += damage;
2201                 dir.nr++;
2202         }
2203
2204         /* This can happen even with many files, if everything was renames */
2205         if (!changed)
2206                 return;
2207
2208         /* Show all directories with more than x% of the changes */
2209         QSORT(dir.files, dir.nr, dirstat_compare);
2210         gather_dirstat(options, &dir, changed, "", 0);
2211 }
2212
2213 static void free_diffstat_info(struct diffstat_t *diffstat)
2214 {
2215         int i;
2216         for (i = 0; i < diffstat->nr; i++) {
2217                 struct diffstat_file *f = diffstat->files[i];
2218                 if (f->name != f->print_name)
2219                         free(f->print_name);
2220                 free(f->name);
2221                 free(f->from_name);
2222                 free(f);
2223         }
2224         free(diffstat->files);
2225 }
2226
2227 struct checkdiff_t {
2228         const char *filename;
2229         int lineno;
2230         int conflict_marker_size;
2231         struct diff_options *o;
2232         unsigned ws_rule;
2233         unsigned status;
2234 };
2235
2236 static int is_conflict_marker(const char *line, int marker_size, unsigned long len)
2237 {
2238         char firstchar;
2239         int cnt;
2240
2241         if (len < marker_size + 1)
2242                 return 0;
2243         firstchar = line[0];
2244         switch (firstchar) {
2245         case '=': case '>': case '<': case '|':
2246                 break;
2247         default:
2248                 return 0;
2249         }
2250         for (cnt = 1; cnt < marker_size; cnt++)
2251                 if (line[cnt] != firstchar)
2252                         return 0;
2253         /* line[1] thru line[marker_size-1] are same as firstchar */
2254         if (len < marker_size + 1 || !isspace(line[marker_size]))
2255                 return 0;
2256         return 1;
2257 }
2258
2259 static void checkdiff_consume(void *priv, char *line, unsigned long len)
2260 {
2261         struct checkdiff_t *data = priv;
2262         int marker_size = data->conflict_marker_size;
2263         const char *ws = diff_get_color(data->o->use_color, DIFF_WHITESPACE);
2264         const char *reset = diff_get_color(data->o->use_color, DIFF_RESET);
2265         const char *set = diff_get_color(data->o->use_color, DIFF_FILE_NEW);
2266         char *err;
2267         const char *line_prefix;
2268
2269         assert(data->o);
2270         line_prefix = diff_line_prefix(data->o);
2271
2272         if (line[0] == '+') {
2273                 unsigned bad;
2274                 data->lineno++;
2275                 if (is_conflict_marker(line + 1, marker_size, len - 1)) {
2276                         data->status |= 1;
2277                         fprintf(data->o->file,
2278                                 "%s%s:%d: leftover conflict marker\n",
2279                                 line_prefix, data->filename, data->lineno);
2280                 }
2281                 bad = ws_check(line + 1, len - 1, data->ws_rule);
2282                 if (!bad)
2283                         return;
2284                 data->status |= bad;
2285                 err = whitespace_error_string(bad);
2286                 fprintf(data->o->file, "%s%s:%d: %s.\n",
2287                         line_prefix, data->filename, data->lineno, err);
2288                 free(err);
2289                 emit_line(data->o, set, reset, line, 1);
2290                 ws_check_emit(line + 1, len - 1, data->ws_rule,
2291                               data->o->file, set, reset, ws);
2292         } else if (line[0] == ' ') {
2293                 data->lineno++;
2294         } else if (line[0] == '@') {
2295                 char *plus = strchr(line, '+');
2296                 if (plus)
2297                         data->lineno = strtol(plus, NULL, 10) - 1;
2298                 else
2299                         die("invalid diff");
2300         }
2301 }
2302
2303 static unsigned char *deflate_it(char *data,
2304                                  unsigned long size,
2305                                  unsigned long *result_size)
2306 {
2307         int bound;
2308         unsigned char *deflated;
2309         git_zstream stream;
2310
2311         git_deflate_init(&stream, zlib_compression_level);
2312         bound = git_deflate_bound(&stream, size);
2313         deflated = xmalloc(bound);
2314         stream.next_out = deflated;
2315         stream.avail_out = bound;
2316
2317         stream.next_in = (unsigned char *)data;
2318         stream.avail_in = size;
2319         while (git_deflate(&stream, Z_FINISH) == Z_OK)
2320                 ; /* nothing */
2321         git_deflate_end(&stream);
2322         *result_size = stream.total_out;
2323         return deflated;
2324 }
2325
2326 static void emit_binary_diff_body(FILE *file, mmfile_t *one, mmfile_t *two,
2327                                   const char *prefix)
2328 {
2329         void *cp;
2330         void *delta;
2331         void *deflated;
2332         void *data;
2333         unsigned long orig_size;
2334         unsigned long delta_size;
2335         unsigned long deflate_size;
2336         unsigned long data_size;
2337
2338         /* We could do deflated delta, or we could do just deflated two,
2339          * whichever is smaller.
2340          */
2341         delta = NULL;
2342         deflated = deflate_it(two->ptr, two->size, &deflate_size);
2343         if (one->size && two->size) {
2344                 delta = diff_delta(one->ptr, one->size,
2345                                    two->ptr, two->size,
2346                                    &delta_size, deflate_size);
2347                 if (delta) {
2348                         void *to_free = delta;
2349                         orig_size = delta_size;
2350                         delta = deflate_it(delta, delta_size, &delta_size);
2351                         free(to_free);
2352                 }
2353         }
2354
2355         if (delta && delta_size < deflate_size) {
2356                 fprintf(file, "%sdelta %lu\n", prefix, orig_size);
2357                 free(deflated);
2358                 data = delta;
2359                 data_size = delta_size;
2360         }
2361         else {
2362                 fprintf(file, "%sliteral %lu\n", prefix, two->size);
2363                 free(delta);
2364                 data = deflated;
2365                 data_size = deflate_size;
2366         }
2367
2368         /* emit data encoded in base85 */
2369         cp = data;
2370         while (data_size) {
2371                 int bytes = (52 < data_size) ? 52 : data_size;
2372                 char line[70];
2373                 data_size -= bytes;
2374                 if (bytes <= 26)
2375                         line[0] = bytes + 'A' - 1;
2376                 else
2377                         line[0] = bytes - 26 + 'a' - 1;
2378                 encode_85(line + 1, cp, bytes);
2379                 cp = (char *) cp + bytes;
2380                 fprintf(file, "%s", prefix);
2381                 fputs(line, file);
2382                 fputc('\n', file);
2383         }
2384         fprintf(file, "%s\n", prefix);
2385         free(data);
2386 }
2387
2388 static void emit_binary_diff(FILE *file, mmfile_t *one, mmfile_t *two,
2389                              const char *prefix)
2390 {
2391         fprintf(file, "%sGIT binary patch\n", prefix);
2392         emit_binary_diff_body(file, one, two, prefix);
2393         emit_binary_diff_body(file, two, one, prefix);
2394 }
2395
2396 int diff_filespec_is_binary(struct diff_filespec *one)
2397 {
2398         if (one->is_binary == -1) {
2399                 diff_filespec_load_driver(one);
2400                 if (one->driver->binary != -1)
2401                         one->is_binary = one->driver->binary;
2402                 else {
2403                         if (!one->data && DIFF_FILE_VALID(one))
2404                                 diff_populate_filespec(one, CHECK_BINARY);
2405                         if (one->is_binary == -1 && one->data)
2406                                 one->is_binary = buffer_is_binary(one->data,
2407                                                 one->size);
2408                         if (one->is_binary == -1)
2409                                 one->is_binary = 0;
2410                 }
2411         }
2412         return one->is_binary;
2413 }
2414
2415 static const struct userdiff_funcname *diff_funcname_pattern(struct diff_filespec *one)
2416 {
2417         diff_filespec_load_driver(one);
2418         return one->driver->funcname.pattern ? &one->driver->funcname : NULL;
2419 }
2420
2421 void diff_set_mnemonic_prefix(struct diff_options *options, const char *a, const char *b)
2422 {
2423         if (!options->a_prefix)
2424                 options->a_prefix = a;
2425         if (!options->b_prefix)
2426                 options->b_prefix = b;
2427 }
2428
2429 struct userdiff_driver *get_textconv(struct diff_filespec *one)
2430 {
2431         if (!DIFF_FILE_VALID(one))
2432                 return NULL;
2433
2434         diff_filespec_load_driver(one);
2435         return userdiff_get_textconv(one->driver);
2436 }
2437
2438 static void builtin_diff(const char *name_a,
2439                          const char *name_b,
2440                          struct diff_filespec *one,
2441                          struct diff_filespec *two,
2442                          const char *xfrm_msg,
2443                          int must_show_header,
2444                          struct diff_options *o,
2445                          int complete_rewrite)
2446 {
2447         mmfile_t mf1, mf2;
2448         const char *lbl[2];
2449         char *a_one, *b_two;
2450         const char *meta = diff_get_color_opt(o, DIFF_METAINFO);
2451         const char *reset = diff_get_color_opt(o, DIFF_RESET);
2452         const char *a_prefix, *b_prefix;
2453         struct userdiff_driver *textconv_one = NULL;
2454         struct userdiff_driver *textconv_two = NULL;
2455         struct strbuf header = STRBUF_INIT;
2456         const char *line_prefix = diff_line_prefix(o);
2457
2458         diff_set_mnemonic_prefix(o, "a/", "b/");
2459         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
2460                 a_prefix = o->b_prefix;
2461                 b_prefix = o->a_prefix;
2462         } else {
2463                 a_prefix = o->a_prefix;
2464                 b_prefix = o->b_prefix;
2465         }
2466
2467         if (o->submodule_format == DIFF_SUBMODULE_LOG &&
2468             (!one->mode || S_ISGITLINK(one->mode)) &&
2469             (!two->mode || S_ISGITLINK(two->mode))) {
2470                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2471                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2472                 show_submodule_summary(o->file, one->path ? one->path : two->path,
2473                                 line_prefix,
2474                                 &one->oid, &two->oid,
2475                                 two->dirty_submodule,
2476                                 meta, del, add, reset);
2477                 return;
2478         } else if (o->submodule_format == DIFF_SUBMODULE_INLINE_DIFF &&
2479                    (!one->mode || S_ISGITLINK(one->mode)) &&
2480                    (!two->mode || S_ISGITLINK(two->mode))) {
2481                 const char *del = diff_get_color_opt(o, DIFF_FILE_OLD);
2482                 const char *add = diff_get_color_opt(o, DIFF_FILE_NEW);
2483                 show_submodule_inline_diff(o->file, one->path ? one->path : two->path,
2484                                 line_prefix,
2485                                 &one->oid, &two->oid,
2486                                 two->dirty_submodule,
2487                                 meta, del, add, reset, o);
2488                 return;
2489         }
2490
2491         if (DIFF_OPT_TST(o, ALLOW_TEXTCONV)) {
2492                 textconv_one = get_textconv(one);
2493                 textconv_two = get_textconv(two);
2494         }
2495
2496         /* Never use a non-valid filename anywhere if at all possible */
2497         name_a = DIFF_FILE_VALID(one) ? name_a : name_b;
2498         name_b = DIFF_FILE_VALID(two) ? name_b : name_a;
2499
2500         a_one = quote_two(a_prefix, name_a + (*name_a == '/'));
2501         b_two = quote_two(b_prefix, name_b + (*name_b == '/'));
2502         lbl[0] = DIFF_FILE_VALID(one) ? a_one : "/dev/null";
2503         lbl[1] = DIFF_FILE_VALID(two) ? b_two : "/dev/null";
2504         strbuf_addf(&header, "%s%sdiff --git %s %s%s\n", line_prefix, meta, a_one, b_two, reset);
2505         if (lbl[0][0] == '/') {
2506                 /* /dev/null */
2507                 strbuf_addf(&header, "%s%snew file mode %06o%s\n", line_prefix, meta, two->mode, reset);
2508                 if (xfrm_msg)
2509                         strbuf_addstr(&header, xfrm_msg);
2510                 must_show_header = 1;
2511         }
2512         else if (lbl[1][0] == '/') {
2513                 strbuf_addf(&header, "%s%sdeleted file mode %06o%s\n", line_prefix, meta, one->mode, reset);
2514                 if (xfrm_msg)
2515                         strbuf_addstr(&header, xfrm_msg);
2516                 must_show_header = 1;
2517         }
2518         else {
2519                 if (one->mode != two->mode) {
2520                         strbuf_addf(&header, "%s%sold mode %06o%s\n", line_prefix, meta, one->mode, reset);
2521                         strbuf_addf(&header, "%s%snew mode %06o%s\n", line_prefix, meta, two->mode, reset);
2522                         must_show_header = 1;
2523                 }
2524                 if (xfrm_msg)
2525                         strbuf_addstr(&header, xfrm_msg);
2526
2527                 /*
2528                  * we do not run diff between different kind
2529                  * of objects.
2530                  */
2531                 if ((one->mode ^ two->mode) & S_IFMT)
2532                         goto free_ab_and_return;
2533                 if (complete_rewrite &&
2534                     (textconv_one || !diff_filespec_is_binary(one)) &&
2535                     (textconv_two || !diff_filespec_is_binary(two))) {
2536                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2537                                          header.buf, header.len, 0);
2538                         strbuf_reset(&header);
2539                         emit_rewrite_diff(name_a, name_b, one, two,
2540                                                 textconv_one, textconv_two, o);
2541                         o->found_changes = 1;
2542                         goto free_ab_and_return;
2543                 }
2544         }
2545
2546         if (o->irreversible_delete && lbl[1][0] == '/') {
2547                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf,
2548                                  header.len, 0);
2549                 strbuf_reset(&header);
2550                 goto free_ab_and_return;
2551         } else if (!DIFF_OPT_TST(o, TEXT) &&
2552             ( (!textconv_one && diff_filespec_is_binary(one)) ||
2553               (!textconv_two && diff_filespec_is_binary(two)) )) {
2554                 struct strbuf sb = STRBUF_INIT;
2555                 if (!one->data && !two->data &&
2556                     S_ISREG(one->mode) && S_ISREG(two->mode) &&
2557                     !DIFF_OPT_TST(o, BINARY)) {
2558                         if (!oidcmp(&one->oid, &two->oid)) {
2559                                 if (must_show_header)
2560                                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2561                                                          header.buf, header.len,
2562                                                          0);
2563                                 goto free_ab_and_return;
2564                         }
2565                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2566                                          header.buf, header.len, 0);
2567                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
2568                                     diff_line_prefix(o), lbl[0], lbl[1]);
2569                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
2570                                          sb.buf, sb.len, 0);
2571                         strbuf_release(&sb);
2572                         goto free_ab_and_return;
2573                 }
2574                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2575                         die("unable to read files to diff");
2576                 /* Quite common confusing case */
2577                 if (mf1.size == mf2.size &&
2578                     !memcmp(mf1.ptr, mf2.ptr, mf1.size)) {
2579                         if (must_show_header)
2580                                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2581                                                  header.buf, header.len, 0);
2582                         goto free_ab_and_return;
2583                 }
2584                 emit_diff_symbol(o, DIFF_SYMBOL_HEADER, header.buf, header.len, 0);
2585                 strbuf_reset(&header);
2586                 if (DIFF_OPT_TST(o, BINARY))
2587                         emit_binary_diff(o->file, &mf1, &mf2, line_prefix);
2588                 else {
2589                         strbuf_addf(&sb, "%sBinary files %s and %s differ\n",
2590                                     diff_line_prefix(o), lbl[0], lbl[1]);
2591                         emit_diff_symbol(o, DIFF_SYMBOL_BINARY_FILES,
2592                                          sb.buf, sb.len, 0);
2593                         strbuf_release(&sb);
2594                 }
2595                 o->found_changes = 1;
2596         } else {
2597                 /* Crazy xdl interfaces.. */
2598                 const char *diffopts = getenv("GIT_DIFF_OPTS");
2599                 const char *v;
2600                 xpparam_t xpp;
2601                 xdemitconf_t xecfg;
2602                 struct emit_callback ecbdata;
2603                 const struct userdiff_funcname *pe;
2604
2605                 if (must_show_header) {
2606                         emit_diff_symbol(o, DIFF_SYMBOL_HEADER,
2607                                          header.buf, header.len, 0);
2608                         strbuf_reset(&header);
2609                 }
2610
2611                 mf1.size = fill_textconv(textconv_one, one, &mf1.ptr);
2612                 mf2.size = fill_textconv(textconv_two, two, &mf2.ptr);
2613
2614                 pe = diff_funcname_pattern(one);
2615                 if (!pe)
2616                         pe = diff_funcname_pattern(two);
2617
2618                 memset(&xpp, 0, sizeof(xpp));
2619                 memset(&xecfg, 0, sizeof(xecfg));
2620                 memset(&ecbdata, 0, sizeof(ecbdata));
2621                 ecbdata.label_path = lbl;
2622                 ecbdata.color_diff = want_color(o->use_color);
2623                 ecbdata.ws_rule = whitespace_rule(name_b);
2624                 if (ecbdata.ws_rule & WS_BLANK_AT_EOF)
2625                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2626                 ecbdata.opt = o;
2627                 ecbdata.header = header.len ? &header : NULL;
2628                 xpp.flags = o->xdl_opts;
2629                 xecfg.ctxlen = o->context;
2630                 xecfg.interhunkctxlen = o->interhunkcontext;
2631                 xecfg.flags = XDL_EMIT_FUNCNAMES;
2632                 if (DIFF_OPT_TST(o, FUNCCONTEXT))
2633                         xecfg.flags |= XDL_EMIT_FUNCCONTEXT;
2634                 if (pe)
2635                         xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
2636                 if (!diffopts)
2637                         ;
2638                 else if (skip_prefix(diffopts, "--unified=", &v))
2639                         xecfg.ctxlen = strtoul(v, NULL, 10);
2640                 else if (skip_prefix(diffopts, "-u", &v))
2641                         xecfg.ctxlen = strtoul(v, NULL, 10);
2642                 if (o->word_diff)
2643                         init_diff_words_data(&ecbdata, o, one, two);
2644                 if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
2645                                   &xpp, &xecfg))
2646                         die("unable to generate diff for %s", one->path);
2647                 if (o->word_diff)
2648                         free_diff_words_data(&ecbdata);
2649                 if (textconv_one)
2650                         free(mf1.ptr);
2651                 if (textconv_two)
2652                         free(mf2.ptr);
2653                 xdiff_clear_find_func(&xecfg);
2654         }
2655
2656  free_ab_and_return:
2657         strbuf_release(&header);
2658         diff_free_filespec_data(one);
2659         diff_free_filespec_data(two);
2660         free(a_one);
2661         free(b_two);
2662         return;
2663 }
2664
2665 static void builtin_diffstat(const char *name_a, const char *name_b,
2666                              struct diff_filespec *one,
2667                              struct diff_filespec *two,
2668                              struct diffstat_t *diffstat,
2669                              struct diff_options *o,
2670                              struct diff_filepair *p)
2671 {
2672         mmfile_t mf1, mf2;
2673         struct diffstat_file *data;
2674         int same_contents;
2675         int complete_rewrite = 0;
2676
2677         if (!DIFF_PAIR_UNMERGED(p)) {
2678                 if (p->status == DIFF_STATUS_MODIFIED && p->score)
2679                         complete_rewrite = 1;
2680         }
2681
2682         data = diffstat_add(diffstat, name_a, name_b);
2683         data->is_interesting = p->status != DIFF_STATUS_UNKNOWN;
2684
2685         if (!one || !two) {
2686                 data->is_unmerged = 1;
2687                 return;
2688         }
2689
2690         same_contents = !oidcmp(&one->oid, &two->oid);
2691
2692         if (diff_filespec_is_binary(one) || diff_filespec_is_binary(two)) {
2693                 data->is_binary = 1;
2694                 if (same_contents) {
2695                         data->added = 0;
2696                         data->deleted = 0;
2697                 } else {
2698                         data->added = diff_filespec_size(two);
2699                         data->deleted = diff_filespec_size(one);
2700                 }
2701         }
2702
2703         else if (complete_rewrite) {
2704                 diff_populate_filespec(one, 0);
2705                 diff_populate_filespec(two, 0);
2706                 data->deleted = count_lines(one->data, one->size);
2707                 data->added = count_lines(two->data, two->size);
2708         }
2709
2710         else if (!same_contents) {
2711                 /* Crazy xdl interfaces.. */
2712                 xpparam_t xpp;
2713                 xdemitconf_t xecfg;
2714
2715                 if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2716                         die("unable to read files to diff");
2717
2718                 memset(&xpp, 0, sizeof(xpp));
2719                 memset(&xecfg, 0, sizeof(xecfg));
2720                 xpp.flags = o->xdl_opts;
2721                 xecfg.ctxlen = o->context;
2722                 xecfg.interhunkctxlen = o->interhunkcontext;
2723                 if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
2724                                   &xpp, &xecfg))
2725                         die("unable to generate diffstat for %s", one->path);
2726         }
2727
2728         diff_free_filespec_data(one);
2729         diff_free_filespec_data(two);
2730 }
2731
2732 static void builtin_checkdiff(const char *name_a, const char *name_b,
2733                               const char *attr_path,
2734                               struct diff_filespec *one,
2735                               struct diff_filespec *two,
2736                               struct diff_options *o)
2737 {
2738         mmfile_t mf1, mf2;
2739         struct checkdiff_t data;
2740
2741         if (!two)
2742                 return;
2743
2744         memset(&data, 0, sizeof(data));
2745         data.filename = name_b ? name_b : name_a;
2746         data.lineno = 0;
2747         data.o = o;
2748         data.ws_rule = whitespace_rule(attr_path);
2749         data.conflict_marker_size = ll_merge_marker_size(attr_path);
2750
2751         if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
2752                 die("unable to read files to diff");
2753
2754         /*
2755          * All the other codepaths check both sides, but not checking
2756          * the "old" side here is deliberate.  We are checking the newly
2757          * introduced changes, and as long as the "new" side is text, we
2758          * can and should check what it introduces.
2759          */
2760         if (diff_filespec_is_binary(two))
2761                 goto free_and_return;
2762         else {
2763                 /* Crazy xdl interfaces.. */
2764                 xpparam_t xpp;
2765                 xdemitconf_t xecfg;
2766
2767                 memset(&xpp, 0, sizeof(xpp));
2768                 memset(&xecfg, 0, sizeof(xecfg));
2769                 xecfg.ctxlen = 1; /* at least one context line */
2770                 xpp.flags = 0;
2771                 if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
2772                                   &xpp, &xecfg))
2773                         die("unable to generate checkdiff for %s", one->path);
2774
2775                 if (data.ws_rule & WS_BLANK_AT_EOF) {
2776                         struct emit_callback ecbdata;
2777                         int blank_at_eof;
2778
2779                         ecbdata.ws_rule = data.ws_rule;
2780                         check_blank_at_eof(&mf1, &mf2, &ecbdata);
2781                         blank_at_eof = ecbdata.blank_at_eof_in_postimage;
2782
2783                         if (blank_at_eof) {
2784                                 static char *err;
2785                                 if (!err)
2786                                         err = whitespace_error_string(WS_BLANK_AT_EOF);
2787                                 fprintf(o->file, "%s:%d: %s.\n",
2788                                         data.filename, blank_at_eof, err);
2789                                 data.status = 1; /* report errors */
2790                         }
2791                 }
2792         }
2793  free_and_return:
2794         diff_free_filespec_data(one);
2795         diff_free_filespec_data(two);
2796         if (data.status)
2797                 DIFF_OPT_SET(o, CHECK_FAILED);
2798 }
2799
2800 struct diff_filespec *alloc_filespec(const char *path)
2801 {
2802         struct diff_filespec *spec;
2803
2804         FLEXPTR_ALLOC_STR(spec, path, path);
2805         spec->count = 1;
2806         spec->is_binary = -1;
2807         return spec;
2808 }
2809
2810 void free_filespec(struct diff_filespec *spec)
2811 {
2812         if (!--spec->count) {
2813                 diff_free_filespec_data(spec);
2814                 free(spec);
2815         }
2816 }
2817
2818 void fill_filespec(struct diff_filespec *spec, const struct object_id *oid,
2819                    int oid_valid, unsigned short mode)
2820 {
2821         if (mode) {
2822                 spec->mode = canon_mode(mode);
2823                 oidcpy(&spec->oid, oid);
2824                 spec->oid_valid = oid_valid;
2825         }
2826 }
2827
2828 /*
2829  * Given a name and sha1 pair, if the index tells us the file in
2830  * the work tree has that object contents, return true, so that
2831  * prepare_temp_file() does not have to inflate and extract.
2832  */
2833 static int reuse_worktree_file(const char *name, const struct object_id *oid, int want_file)
2834 {
2835         const struct cache_entry *ce;
2836         struct stat st;
2837         int pos, len;
2838
2839         /*
2840          * We do not read the cache ourselves here, because the
2841          * benchmark with my previous version that always reads cache
2842          * shows that it makes things worse for diff-tree comparing
2843          * two linux-2.6 kernel trees in an already checked out work
2844          * tree.  This is because most diff-tree comparisons deal with
2845          * only a small number of files, while reading the cache is
2846          * expensive for a large project, and its cost outweighs the
2847          * savings we get by not inflating the object to a temporary
2848          * file.  Practically, this code only helps when we are used
2849          * by diff-cache --cached, which does read the cache before
2850          * calling us.
2851          */
2852         if (!active_cache)
2853                 return 0;
2854
2855         /* We want to avoid the working directory if our caller
2856          * doesn't need the data in a normal file, this system
2857          * is rather slow with its stat/open/mmap/close syscalls,
2858          * and the object is contained in a pack file.  The pack
2859          * is probably already open and will be faster to obtain
2860          * the data through than the working directory.  Loose
2861          * objects however would tend to be slower as they need
2862          * to be individually opened and inflated.
2863          */
2864         if (!FAST_WORKING_DIRECTORY && !want_file && has_sha1_pack(oid->hash))
2865                 return 0;
2866
2867         /*
2868          * Similarly, if we'd have to convert the file contents anyway, that
2869          * makes the optimization not worthwhile.
2870          */
2871         if (!want_file && would_convert_to_git(&the_index, name))
2872                 return 0;
2873
2874         len = strlen(name);
2875         pos = cache_name_pos(name, len);
2876         if (pos < 0)
2877                 return 0;
2878         ce = active_cache[pos];
2879
2880         /*
2881          * This is not the sha1 we are looking for, or
2882          * unreusable because it is not a regular file.
2883          */
2884         if (oidcmp(oid, &ce->oid) || !S_ISREG(ce->ce_mode))
2885                 return 0;
2886
2887         /*
2888          * If ce is marked as "assume unchanged", there is no
2889          * guarantee that work tree matches what we are looking for.
2890          */
2891         if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
2892                 return 0;
2893
2894         /*
2895          * If ce matches the file in the work tree, we can reuse it.
2896          */
2897         if (ce_uptodate(ce) ||
2898             (!lstat(name, &st) && !ce_match_stat(ce, &st, 0)))
2899                 return 1;
2900
2901         return 0;
2902 }
2903
2904 static int diff_populate_gitlink(struct diff_filespec *s, int size_only)
2905 {
2906         struct strbuf buf = STRBUF_INIT;
2907         char *dirty = "";
2908
2909         /* Are we looking at the work tree? */
2910         if (s->dirty_submodule)
2911                 dirty = "-dirty";
2912
2913         strbuf_addf(&buf, "Subproject commit %s%s\n",
2914                     oid_to_hex(&s->oid), dirty);
2915         s->size = buf.len;
2916         if (size_only) {
2917                 s->data = NULL;
2918                 strbuf_release(&buf);
2919         } else {
2920                 s->data = strbuf_detach(&buf, NULL);
2921                 s->should_free = 1;
2922         }
2923         return 0;
2924 }
2925
2926 /*
2927  * While doing rename detection and pickaxe operation, we may need to
2928  * grab the data for the blob (or file) for our own in-core comparison.
2929  * diff_filespec has data and size fields for this purpose.
2930  */
2931 int diff_populate_filespec(struct diff_filespec *s, unsigned int flags)
2932 {
2933         int size_only = flags & CHECK_SIZE_ONLY;
2934         int err = 0;
2935         /*
2936          * demote FAIL to WARN to allow inspecting the situation
2937          * instead of refusing.
2938          */
2939         enum safe_crlf crlf_warn = (safe_crlf == SAFE_CRLF_FAIL
2940                                     ? SAFE_CRLF_WARN
2941                                     : safe_crlf);
2942
2943         if (!DIFF_FILE_VALID(s))
2944                 die("internal error: asking to populate invalid file.");
2945         if (S_ISDIR(s->mode))
2946                 return -1;
2947
2948         if (s->data)
2949                 return 0;
2950
2951         if (size_only && 0 < s->size)
2952                 return 0;
2953
2954         if (S_ISGITLINK(s->mode))
2955                 return diff_populate_gitlink(s, size_only);
2956
2957         if (!s->oid_valid ||
2958             reuse_worktree_file(s->path, &s->oid, 0)) {
2959                 struct strbuf buf = STRBUF_INIT;
2960                 struct stat st;
2961                 int fd;
2962
2963                 if (lstat(s->path, &st) < 0) {
2964                         if (errno == ENOENT) {
2965                         err_empty:
2966                                 err = -1;
2967                         empty:
2968                                 s->data = (char *)"";
2969                                 s->size = 0;
2970                                 return err;
2971                         }
2972                 }
2973                 s->size = xsize_t(st.st_size);
2974                 if (!s->size)
2975                         goto empty;
2976                 if (S_ISLNK(st.st_mode)) {
2977                         struct strbuf sb = STRBUF_INIT;
2978
2979                         if (strbuf_readlink(&sb, s->path, s->size))
2980                                 goto err_empty;
2981                         s->size = sb.len;
2982                         s->data = strbuf_detach(&sb, NULL);
2983                         s->should_free = 1;
2984                         return 0;
2985                 }
2986
2987                 /*
2988                  * Even if the caller would be happy with getting
2989                  * only the size, we cannot return early at this
2990                  * point if the path requires us to run the content
2991                  * conversion.
2992                  */
2993                 if (size_only && !would_convert_to_git(&the_index, s->path))
2994                         return 0;
2995
2996                 /*
2997                  * Note: this check uses xsize_t(st.st_size) that may
2998                  * not be the true size of the blob after it goes
2999                  * through convert_to_git().  This may not strictly be
3000                  * correct, but the whole point of big_file_threshold
3001                  * and is_binary check being that we want to avoid
3002                  * opening the file and inspecting the contents, this
3003                  * is probably fine.
3004                  */
3005                 if ((flags & CHECK_BINARY) &&
3006                     s->size > big_file_threshold && s->is_binary == -1) {
3007                         s->is_binary = 1;
3008                         return 0;
3009                 }
3010                 fd = open(s->path, O_RDONLY);
3011                 if (fd < 0)
3012                         goto err_empty;
3013                 s->data = xmmap(NULL, s->size, PROT_READ, MAP_PRIVATE, fd, 0);
3014                 close(fd);
3015                 s->should_munmap = 1;
3016
3017                 /*
3018                  * Convert from working tree format to canonical git format
3019                  */
3020                 if (convert_to_git(&the_index, s->path, s->data, s->size, &buf, crlf_warn)) {
3021                         size_t size = 0;
3022                         munmap(s->data, s->size);
3023                         s->should_munmap = 0;
3024                         s->data = strbuf_detach(&buf, &size);
3025                         s->size = size;
3026                         s->should_free = 1;
3027                 }
3028         }
3029         else {
3030                 enum object_type type;
3031                 if (size_only || (flags & CHECK_BINARY)) {
3032                         type = sha1_object_info(s->oid.hash, &s->size);
3033                         if (type < 0)
3034                                 die("unable to read %s",
3035                                     oid_to_hex(&s->oid));
3036                         if (size_only)
3037                                 return 0;
3038                         if (s->size > big_file_threshold && s->is_binary == -1) {
3039                                 s->is_binary = 1;
3040                                 return 0;
3041                         }
3042                 }
3043                 s->data = read_sha1_file(s->oid.hash, &type, &s->size);
3044                 if (!s->data)
3045                         die("unable to read %s", oid_to_hex(&s->oid));
3046                 s->should_free = 1;
3047         }
3048         return 0;
3049 }
3050
3051 void diff_free_filespec_blob(struct diff_filespec *s)
3052 {
3053         if (s->should_free)
3054                 free(s->data);
3055         else if (s->should_munmap)
3056                 munmap(s->data, s->size);
3057
3058         if (s->should_free || s->should_munmap) {
3059                 s->should_free = s->should_munmap = 0;
3060                 s->data = NULL;
3061         }
3062 }
3063
3064 void diff_free_filespec_data(struct diff_filespec *s)
3065 {
3066         diff_free_filespec_blob(s);
3067         FREE_AND_NULL(s->cnt_data);
3068 }
3069
3070 static void prep_temp_blob(const char *path, struct diff_tempfile *temp,
3071                            void *blob,
3072                            unsigned long size,
3073                            const struct object_id *oid,
3074                            int mode)
3075 {
3076         int fd;
3077         struct strbuf buf = STRBUF_INIT;
3078         struct strbuf template = STRBUF_INIT;
3079         char *path_dup = xstrdup(path);
3080         const char *base = basename(path_dup);
3081
3082         /* Generate "XXXXXX_basename.ext" */
3083         strbuf_addstr(&template, "XXXXXX_");
3084         strbuf_addstr(&template, base);
3085
3086         fd = mks_tempfile_ts(&temp->tempfile, template.buf, strlen(base) + 1);
3087         if (fd < 0)
3088                 die_errno("unable to create temp-file");
3089         if (convert_to_working_tree(path,
3090                         (const char *)blob, (size_t)size, &buf)) {
3091                 blob = buf.buf;
3092                 size = buf.len;
3093         }
3094         if (write_in_full(fd, blob, size) != size)
3095                 die_errno("unable to write temp-file");
3096         close_tempfile(&temp->tempfile);
3097         temp->name = get_tempfile_path(&temp->tempfile);
3098         oid_to_hex_r(temp->hex, oid);
3099         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", mode);
3100         strbuf_release(&buf);
3101         strbuf_release(&template);
3102         free(path_dup);
3103 }
3104
3105 static struct diff_tempfile *prepare_temp_file(const char *name,
3106                 struct diff_filespec *one)
3107 {
3108         struct diff_tempfile *temp = claim_diff_tempfile();
3109
3110         if (!DIFF_FILE_VALID(one)) {
3111         not_a_valid_file:
3112                 /* A '-' entry produces this for file-2, and
3113                  * a '+' entry produces this for file-1.
3114                  */
3115                 temp->name = "/dev/null";
3116                 xsnprintf(temp->hex, sizeof(temp->hex), ".");
3117                 xsnprintf(temp->mode, sizeof(temp->mode), ".");
3118                 return temp;
3119         }
3120
3121         if (!S_ISGITLINK(one->mode) &&
3122             (!one->oid_valid ||
3123              reuse_worktree_file(name, &one->oid, 1))) {
3124                 struct stat st;
3125                 if (lstat(name, &st) < 0) {
3126                         if (errno == ENOENT)
3127                                 goto not_a_valid_file;
3128                         die_errno("stat(%s)", name);
3129                 }
3130                 if (S_ISLNK(st.st_mode)) {
3131                         struct strbuf sb = STRBUF_INIT;
3132                         if (strbuf_readlink(&sb, name, st.st_size) < 0)
3133                                 die_errno("readlink(%s)", name);
3134                         prep_temp_blob(name, temp, sb.buf, sb.len,
3135                                        (one->oid_valid ?
3136                                         &one->oid : &null_oid),
3137                                        (one->oid_valid ?
3138                                         one->mode : S_IFLNK));
3139                         strbuf_release(&sb);
3140                 }
3141                 else {
3142                         /* we can borrow from the file in the work tree */
3143                         temp->name = name;
3144                         if (!one->oid_valid)
3145                                 oid_to_hex_r(temp->hex, &null_oid);
3146                         else
3147                                 oid_to_hex_r(temp->hex, &one->oid);
3148                         /* Even though we may sometimes borrow the
3149                          * contents from the work tree, we always want
3150                          * one->mode.  mode is trustworthy even when
3151                          * !(one->oid_valid), as long as
3152                          * DIFF_FILE_VALID(one).
3153                          */
3154                         xsnprintf(temp->mode, sizeof(temp->mode), "%06o", one->mode);
3155                 }
3156                 return temp;
3157         }
3158         else {
3159                 if (diff_populate_filespec(one, 0))
3160                         die("cannot read data blob for %s", one->path);
3161                 prep_temp_blob(name, temp, one->data, one->size,
3162                                &one->oid, one->mode);
3163         }
3164         return temp;
3165 }
3166
3167 static void add_external_diff_name(struct argv_array *argv,
3168                                    const char *name,
3169                                    struct diff_filespec *df)
3170 {
3171         struct diff_tempfile *temp = prepare_temp_file(name, df);
3172         argv_array_push(argv, temp->name);
3173         argv_array_push(argv, temp->hex);
3174         argv_array_push(argv, temp->mode);
3175 }
3176
3177 /* An external diff command takes:
3178  *
3179  * diff-cmd name infile1 infile1-sha1 infile1-mode \
3180  *               infile2 infile2-sha1 infile2-mode [ rename-to ]
3181  *
3182  */
3183 static void run_external_diff(const char *pgm,
3184                               const char *name,
3185                               const char *other,
3186                               struct diff_filespec *one,
3187                               struct diff_filespec *two,
3188                               const char *xfrm_msg,
3189                               int complete_rewrite,
3190                               struct diff_options *o)
3191 {
3192         struct argv_array argv = ARGV_ARRAY_INIT;
3193         struct argv_array env = ARGV_ARRAY_INIT;
3194         struct diff_queue_struct *q = &diff_queued_diff;
3195
3196         argv_array_push(&argv, pgm);
3197         argv_array_push(&argv, name);
3198
3199         if (one && two) {
3200                 add_external_diff_name(&argv, name, one);
3201                 if (!other)
3202                         add_external_diff_name(&argv, name, two);
3203                 else {
3204                         add_external_diff_name(&argv, other, two);
3205                         argv_array_push(&argv, other);
3206                         argv_array_push(&argv, xfrm_msg);
3207                 }
3208         }
3209
3210         argv_array_pushf(&env, "GIT_DIFF_PATH_COUNTER=%d", ++o->diff_path_counter);
3211         argv_array_pushf(&env, "GIT_DIFF_PATH_TOTAL=%d", q->nr);
3212
3213         if (run_command_v_opt_cd_env(argv.argv, RUN_USING_SHELL, NULL, env.argv))
3214                 die(_("external diff died, stopping at %s"), name);
3215
3216         remove_tempfile();
3217         argv_array_clear(&argv);
3218         argv_array_clear(&env);
3219 }
3220
3221 static int similarity_index(struct diff_filepair *p)
3222 {
3223         return p->score * 100 / MAX_SCORE;
3224 }
3225
3226 static const char *diff_abbrev_oid(const struct object_id *oid, int abbrev)
3227 {
3228         if (startup_info->have_repository)
3229                 return find_unique_abbrev(oid->hash, abbrev);
3230         else {
3231                 char *hex = oid_to_hex(oid);
3232                 if (abbrev < 0)
3233                         abbrev = FALLBACK_DEFAULT_ABBREV;
3234                 if (abbrev > GIT_SHA1_HEXSZ)
3235                         die("BUG: oid abbreviation out of range: %d", abbrev);
3236                 if (abbrev)
3237                         hex[abbrev] = '\0';
3238                 return hex;
3239         }
3240 }
3241
3242 static void fill_metainfo(struct strbuf *msg,
3243                           const char *name,
3244                           const char *other,
3245                           struct diff_filespec *one,
3246                           struct diff_filespec *two,
3247                           struct diff_options *o,
3248                           struct diff_filepair *p,
3249                           int *must_show_header,
3250                           int use_color)
3251 {
3252         const char *set = diff_get_color(use_color, DIFF_METAINFO);
3253         const char *reset = diff_get_color(use_color, DIFF_RESET);
3254         const char *line_prefix = diff_line_prefix(o);
3255
3256         *must_show_header = 1;
3257         strbuf_init(msg, PATH_MAX * 2 + 300);
3258         switch (p->status) {
3259         case DIFF_STATUS_COPIED:
3260                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3261                             line_prefix, set, similarity_index(p));
3262                 strbuf_addf(msg, "%s\n%s%scopy from ",
3263                             reset,  line_prefix, set);
3264                 quote_c_style(name, msg, NULL, 0);
3265                 strbuf_addf(msg, "%s\n%s%scopy to ", reset, line_prefix, set);
3266                 quote_c_style(other, msg, NULL, 0);
3267                 strbuf_addf(msg, "%s\n", reset);
3268                 break;
3269         case DIFF_STATUS_RENAMED:
3270                 strbuf_addf(msg, "%s%ssimilarity index %d%%",
3271                             line_prefix, set, similarity_index(p));
3272                 strbuf_addf(msg, "%s\n%s%srename from ",
3273                             reset, line_prefix, set);
3274                 quote_c_style(name, msg, NULL, 0);
3275                 strbuf_addf(msg, "%s\n%s%srename to ",
3276                             reset, line_prefix, set);
3277                 quote_c_style(other, msg, NULL, 0);
3278                 strbuf_addf(msg, "%s\n", reset);
3279                 break;
3280         case DIFF_STATUS_MODIFIED:
3281                 if (p->score) {
3282                         strbuf_addf(msg, "%s%sdissimilarity index %d%%%s\n",
3283                                     line_prefix,
3284                                     set, similarity_index(p), reset);
3285                         break;
3286                 }
3287                 /* fallthru */
3288         default:
3289                 *must_show_header = 0;
3290         }
3291         if (one && two && oidcmp(&one->oid, &two->oid)) {
3292                 int abbrev = DIFF_OPT_TST(o, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
3293
3294                 if (DIFF_OPT_TST(o, BINARY)) {
3295                         mmfile_t mf;
3296                         if ((!fill_mmfile(&mf, one) && diff_filespec_is_binary(one)) ||
3297                             (!fill_mmfile(&mf, two) && diff_filespec_is_binary(two)))
3298                                 abbrev = 40;
3299                 }
3300                 strbuf_addf(msg, "%s%sindex %s..%s", line_prefix, set,
3301                             diff_abbrev_oid(&one->oid, abbrev),
3302                             diff_abbrev_oid(&two->oid, abbrev));
3303                 if (one->mode == two->mode)
3304                         strbuf_addf(msg, " %06o", one->mode);
3305                 strbuf_addf(msg, "%s\n", reset);
3306         }
3307 }
3308
3309 static void run_diff_cmd(const char *pgm,
3310                          const char *name,
3311                          const char *other,
3312                          const char *attr_path,
3313                          struct diff_filespec *one,
3314                          struct diff_filespec *two,
3315                          struct strbuf *msg,
3316                          struct diff_options *o,
3317                          struct diff_filepair *p)
3318 {
3319         const char *xfrm_msg = NULL;
3320         int complete_rewrite = (p->status == DIFF_STATUS_MODIFIED) && p->score;
3321         int must_show_header = 0;
3322
3323
3324         if (DIFF_OPT_TST(o, ALLOW_EXTERNAL)) {
3325                 struct userdiff_driver *drv = userdiff_find_by_path(attr_path);
3326                 if (drv && drv->external)
3327                         pgm = drv->external;
3328         }
3329
3330         if (msg) {
3331                 /*
3332                  * don't use colors when the header is intended for an
3333                  * external diff driver
3334                  */
3335                 fill_metainfo(msg, name, other, one, two, o, p,
3336                               &must_show_header,
3337                               want_color(o->use_color) && !pgm);
3338                 xfrm_msg = msg->len ? msg->buf : NULL;
3339         }
3340
3341         if (pgm) {
3342                 run_external_diff(pgm, name, other, one, two, xfrm_msg,
3343                                   complete_rewrite, o);
3344                 return;
3345         }
3346         if (one && two)
3347                 builtin_diff(name, other ? other : name,
3348                              one, two, xfrm_msg, must_show_header,
3349                              o, complete_rewrite);
3350         else
3351                 fprintf(o->file, "* Unmerged path %s\n", name);
3352 }
3353
3354 static void diff_fill_oid_info(struct diff_filespec *one)
3355 {
3356         if (DIFF_FILE_VALID(one)) {
3357                 if (!one->oid_valid) {
3358                         struct stat st;
3359                         if (one->is_stdin) {
3360                                 oidclr(&one->oid);
3361                                 return;
3362                         }
3363                         if (lstat(one->path, &st) < 0)
3364                                 die_errno("stat '%s'", one->path);
3365                         if (index_path(one->oid.hash, one->path, &st, 0))
3366                                 die("cannot hash %s", one->path);
3367                 }
3368         }
3369         else
3370                 oidclr(&one->oid);
3371 }
3372
3373 static void strip_prefix(int prefix_length, const char **namep, const char **otherp)
3374 {
3375         /* Strip the prefix but do not molest /dev/null and absolute paths */
3376         if (*namep && **namep != '/') {
3377                 *namep += prefix_length;
3378                 if (**namep == '/')
3379                         ++*namep;
3380         }
3381         if (*otherp && **otherp != '/') {
3382                 *otherp += prefix_length;
3383                 if (**otherp == '/')
3384                         ++*otherp;
3385         }
3386 }
3387
3388 static void run_diff(struct diff_filepair *p, struct diff_options *o)
3389 {
3390         const char *pgm = external_diff();
3391         struct strbuf msg;
3392         struct diff_filespec *one = p->one;
3393         struct diff_filespec *two = p->two;
3394         const char *name;
3395         const char *other;
3396         const char *attr_path;
3397
3398         name  = one->path;
3399         other = (strcmp(name, two->path) ? two->path : NULL);
3400         attr_path = name;
3401         if (o->prefix_length)
3402                 strip_prefix(o->prefix_length, &name, &other);
3403
3404         if (!DIFF_OPT_TST(o, ALLOW_EXTERNAL))
3405                 pgm = NULL;
3406
3407         if (DIFF_PAIR_UNMERGED(p)) {
3408                 run_diff_cmd(pgm, name, NULL, attr_path,
3409                              NULL, NULL, NULL, o, p);
3410                 return;
3411         }
3412
3413         diff_fill_oid_info(one);
3414         diff_fill_oid_info(two);
3415
3416         if (!pgm &&
3417             DIFF_FILE_VALID(one) && DIFF_FILE_VALID(two) &&
3418             (S_IFMT & one->mode) != (S_IFMT & two->mode)) {
3419                 /*
3420                  * a filepair that changes between file and symlink
3421                  * needs to be split into deletion and creation.
3422                  */
3423                 struct diff_filespec *null = alloc_filespec(two->path);
3424                 run_diff_cmd(NULL, name, other, attr_path,
3425                              one, null, &msg, o, p);
3426                 free(null);
3427                 strbuf_release(&msg);
3428
3429                 null = alloc_filespec(one->path);
3430                 run_diff_cmd(NULL, name, other, attr_path,
3431                              null, two, &msg, o, p);
3432                 free(null);
3433         }
3434         else
3435                 run_diff_cmd(pgm, name, other, attr_path,
3436                              one, two, &msg, o, p);
3437
3438         strbuf_release(&msg);
3439 }
3440
3441 static void run_diffstat(struct diff_filepair *p, struct diff_options *o,
3442                          struct diffstat_t *diffstat)
3443 {
3444         const char *name;
3445         const char *other;
3446
3447         if (DIFF_PAIR_UNMERGED(p)) {
3448                 /* unmerged */
3449                 builtin_diffstat(p->one->path, NULL, NULL, NULL, diffstat, o, p);
3450                 return;
3451         }
3452
3453         name = p->one->path;
3454         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3455
3456         if (o->prefix_length)
3457                 strip_prefix(o->prefix_length, &name, &other);
3458
3459         diff_fill_oid_info(p->one);
3460         diff_fill_oid_info(p->two);
3461
3462         builtin_diffstat(name, other, p->one, p->two, diffstat, o, p);
3463 }
3464
3465 static void run_checkdiff(struct diff_filepair *p, struct diff_options *o)
3466 {
3467         const char *name;
3468         const char *other;
3469         const char *attr_path;
3470
3471         if (DIFF_PAIR_UNMERGED(p)) {
3472                 /* unmerged */
3473                 return;
3474         }
3475
3476         name = p->one->path;
3477         other = (strcmp(name, p->two->path) ? p->two->path : NULL);
3478         attr_path = other ? other : name;
3479
3480         if (o->prefix_length)
3481                 strip_prefix(o->prefix_length, &name, &other);
3482
3483         diff_fill_oid_info(p->one);
3484         diff_fill_oid_info(p->two);
3485
3486         builtin_checkdiff(name, other, attr_path, p->one, p->two, o);
3487 }
3488
3489 void diff_setup(struct diff_options *options)
3490 {
3491         memcpy(options, &default_diff_options, sizeof(*options));
3492
3493         options->file = stdout;
3494
3495         options->abbrev = DEFAULT_ABBREV;
3496         options->line_termination = '\n';
3497         options->break_opt = -1;
3498         options->rename_limit = -1;
3499         options->dirstat_permille = diff_dirstat_permille_default;
3500         options->context = diff_context_default;
3501         options->interhunkcontext = diff_interhunk_context_default;
3502         options->ws_error_highlight = ws_error_highlight_default;
3503         DIFF_OPT_SET(options, RENAME_EMPTY);
3504
3505         /* pathchange left =NULL by default */
3506         options->change = diff_change;
3507         options->add_remove = diff_addremove;
3508         options->use_color = diff_use_color_default;
3509         options->detect_rename = diff_detect_rename_default;
3510         options->xdl_opts |= diff_algorithm;
3511         if (diff_indent_heuristic)
3512                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
3513
3514         options->orderfile = diff_order_file_cfg;
3515
3516         if (diff_no_prefix) {
3517                 options->a_prefix = options->b_prefix = "";
3518         } else if (!diff_mnemonic_prefix) {
3519                 options->a_prefix = "a/";
3520                 options->b_prefix = "b/";
3521         }
3522 }
3523
3524 void diff_setup_done(struct diff_options *options)
3525 {
3526         int count = 0;
3527
3528         if (options->set_default)
3529                 options->set_default(options);
3530
3531         if (options->output_format & DIFF_FORMAT_NAME)
3532                 count++;
3533         if (options->output_format & DIFF_FORMAT_NAME_STATUS)
3534                 count++;
3535         if (options->output_format & DIFF_FORMAT_CHECKDIFF)
3536                 count++;
3537         if (options->output_format & DIFF_FORMAT_NO_OUTPUT)
3538                 count++;
3539         if (count > 1)
3540                 die(_("--name-only, --name-status, --check and -s are mutually exclusive"));
3541
3542         /*
3543          * Most of the time we can say "there are changes"
3544          * only by checking if there are changed paths, but
3545          * --ignore-whitespace* options force us to look
3546          * inside contents.
3547          */
3548
3549         if (DIFF_XDL_TST(options, IGNORE_WHITESPACE) ||
3550             DIFF_XDL_TST(options, IGNORE_WHITESPACE_CHANGE) ||
3551             DIFF_XDL_TST(options, IGNORE_WHITESPACE_AT_EOL))
3552                 DIFF_OPT_SET(options, DIFF_FROM_CONTENTS);
3553         else
3554                 DIFF_OPT_CLR(options, DIFF_FROM_CONTENTS);
3555
3556         if (DIFF_OPT_TST(options, FIND_COPIES_HARDER))
3557                 options->detect_rename = DIFF_DETECT_COPY;
3558
3559         if (!DIFF_OPT_TST(options, RELATIVE_NAME))
3560                 options->prefix = NULL;
3561         if (options->prefix)
3562                 options->prefix_length = strlen(options->prefix);
3563         else
3564                 options->prefix_length = 0;
3565
3566         if (options->output_format & (DIFF_FORMAT_NAME |
3567                                       DIFF_FORMAT_NAME_STATUS |
3568                                       DIFF_FORMAT_CHECKDIFF |
3569                                       DIFF_FORMAT_NO_OUTPUT))
3570                 options->output_format &= ~(DIFF_FORMAT_RAW |
3571                                             DIFF_FORMAT_NUMSTAT |
3572                                             DIFF_FORMAT_DIFFSTAT |
3573                                             DIFF_FORMAT_SHORTSTAT |
3574                                             DIFF_FORMAT_DIRSTAT |
3575                                             DIFF_FORMAT_SUMMARY |
3576                                             DIFF_FORMAT_PATCH);
3577
3578         /*
3579          * These cases always need recursive; we do not drop caller-supplied
3580          * recursive bits for other formats here.
3581          */
3582         if (options->output_format & (DIFF_FORMAT_PATCH |
3583                                       DIFF_FORMAT_NUMSTAT |
3584                                       DIFF_FORMAT_DIFFSTAT |
3585                                       DIFF_FORMAT_SHORTSTAT |
3586                                       DIFF_FORMAT_DIRSTAT |
3587                                       DIFF_FORMAT_SUMMARY |
3588                                       DIFF_FORMAT_CHECKDIFF))
3589                 DIFF_OPT_SET(options, RECURSIVE);
3590         /*
3591          * Also pickaxe would not work very well if you do not say recursive
3592          */
3593         if (options->pickaxe)
3594                 DIFF_OPT_SET(options, RECURSIVE);
3595         /*
3596          * When patches are generated, submodules diffed against the work tree
3597          * must be checked for dirtiness too so it can be shown in the output
3598          */
3599         if (options->output_format & DIFF_FORMAT_PATCH)
3600                 DIFF_OPT_SET(options, DIRTY_SUBMODULES);
3601
3602         if (options->detect_rename && options->rename_limit < 0)
3603                 options->rename_limit = diff_rename_limit_default;
3604         if (options->setup & DIFF_SETUP_USE_CACHE) {
3605                 if (!active_cache)
3606                         /* read-cache does not die even when it fails
3607                          * so it is safe for us to do this here.  Also
3608                          * it does not smudge active_cache or active_nr
3609                          * when it fails, so we do not have to worry about
3610                          * cleaning it up ourselves either.
3611                          */
3612                         read_cache();
3613         }
3614         if (40 < options->abbrev)
3615                 options->abbrev = 40; /* full */
3616
3617         /*
3618          * It does not make sense to show the first hit we happened
3619          * to have found.  It does not make sense not to return with
3620          * exit code in such a case either.
3621          */
3622         if (DIFF_OPT_TST(options, QUICK)) {
3623                 options->output_format = DIFF_FORMAT_NO_OUTPUT;
3624                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
3625         }
3626
3627         options->diff_path_counter = 0;
3628
3629         if (DIFF_OPT_TST(options, FOLLOW_RENAMES) && options->pathspec.nr != 1)
3630                 die(_("--follow requires exactly one pathspec"));
3631 }
3632
3633 static int opt_arg(const char *arg, int arg_short, const char *arg_long, int *val)
3634 {
3635         char c, *eq;
3636         int len;
3637
3638         if (*arg != '-')
3639                 return 0;
3640         c = *++arg;
3641         if (!c)
3642                 return 0;
3643         if (c == arg_short) {
3644                 c = *++arg;
3645                 if (!c)
3646                         return 1;
3647                 if (val && isdigit(c)) {
3648                         char *end;
3649                         int n = strtoul(arg, &end, 10);
3650                         if (*end)
3651                                 return 0;
3652                         *val = n;
3653                         return 1;
3654                 }
3655                 return 0;
3656         }
3657         if (c != '-')
3658                 return 0;
3659         arg++;
3660         eq = strchrnul(arg, '=');
3661         len = eq - arg;
3662         if (!len || strncmp(arg, arg_long, len))
3663                 return 0;
3664         if (*eq) {
3665                 int n;
3666                 char *end;
3667                 if (!isdigit(*++eq))
3668                         return 0;
3669                 n = strtoul(eq, &end, 10);
3670                 if (*end)
3671                         return 0;
3672                 *val = n;
3673         }
3674         return 1;
3675 }
3676
3677 static int diff_scoreopt_parse(const char *opt);
3678
3679 static inline int short_opt(char opt, const char **argv,
3680                             const char **optarg)
3681 {
3682         const char *arg = argv[0];
3683         if (arg[0] != '-' || arg[1] != opt)
3684                 return 0;
3685         if (arg[2] != '\0') {
3686                 *optarg = arg + 2;
3687                 return 1;
3688         }
3689         if (!argv[1])
3690                 die("Option '%c' requires a value", opt);
3691         *optarg = argv[1];
3692         return 2;
3693 }
3694
3695 int parse_long_opt(const char *opt, const char **argv,
3696                    const char **optarg)
3697 {
3698         const char *arg = argv[0];
3699         if (!skip_prefix(arg, "--", &arg))
3700                 return 0;
3701         if (!skip_prefix(arg, opt, &arg))
3702                 return 0;
3703         if (*arg == '=') { /* stuck form: --option=value */
3704                 *optarg = arg + 1;
3705                 return 1;
3706         }
3707         if (*arg != '\0')
3708                 return 0;
3709         /* separate form: --option value */
3710         if (!argv[1])
3711                 die("Option '--%s' requires a value", opt);
3712         *optarg = argv[1];
3713         return 2;
3714 }
3715
3716 static int stat_opt(struct diff_options *options, const char **av)
3717 {
3718         const char *arg = av[0];
3719         char *end;
3720         int width = options->stat_width;
3721         int name_width = options->stat_name_width;
3722         int graph_width = options->stat_graph_width;
3723         int count = options->stat_count;
3724         int argcount = 1;
3725
3726         if (!skip_prefix(arg, "--stat", &arg))
3727                 die("BUG: stat option does not begin with --stat: %s", arg);
3728         end = (char *)arg;
3729
3730         switch (*arg) {
3731         case '-':
3732                 if (skip_prefix(arg, "-width", &arg)) {
3733                         if (*arg == '=')
3734                                 width = strtoul(arg + 1, &end, 10);
3735                         else if (!*arg && !av[1])
3736                                 die_want_option("--stat-width");
3737                         else if (!*arg) {
3738                                 width = strtoul(av[1], &end, 10);
3739                                 argcount = 2;
3740                         }
3741                 } else if (skip_prefix(arg, "-name-width", &arg)) {
3742                         if (*arg == '=')
3743                                 name_width = strtoul(arg + 1, &end, 10);
3744                         else if (!*arg && !av[1])
3745                                 die_want_option("--stat-name-width");
3746                         else if (!*arg) {
3747                                 name_width = strtoul(av[1], &end, 10);
3748                                 argcount = 2;
3749                         }
3750                 } else if (skip_prefix(arg, "-graph-width", &arg)) {
3751                         if (*arg == '=')
3752                                 graph_width = strtoul(arg + 1, &end, 10);
3753                         else if (!*arg && !av[1])
3754                                 die_want_option("--stat-graph-width");
3755                         else if (!*arg) {
3756                                 graph_width = strtoul(av[1], &end, 10);
3757                                 argcount = 2;
3758                         }
3759                 } else if (skip_prefix(arg, "-count", &arg)) {
3760                         if (*arg == '=')
3761                                 count = strtoul(arg + 1, &end, 10);
3762                         else if (!*arg && !av[1])
3763                                 die_want_option("--stat-count");
3764                         else if (!*arg) {
3765                                 count = strtoul(av[1], &end, 10);
3766                                 argcount = 2;
3767                         }
3768                 }
3769                 break;
3770         case '=':
3771                 width = strtoul(arg+1, &end, 10);
3772                 if (*end == ',')
3773                         name_width = strtoul(end+1, &end, 10);
3774                 if (*end == ',')
3775                         count = strtoul(end+1, &end, 10);
3776         }
3777
3778         /* Important! This checks all the error cases! */
3779         if (*end)
3780                 return 0;
3781         options->output_format |= DIFF_FORMAT_DIFFSTAT;
3782         options->stat_name_width = name_width;
3783         options->stat_graph_width = graph_width;
3784         options->stat_width = width;
3785         options->stat_count = count;
3786         return argcount;
3787 }
3788
3789 static int parse_dirstat_opt(struct diff_options *options, const char *params)
3790 {
3791         struct strbuf errmsg = STRBUF_INIT;
3792         if (parse_dirstat_params(options, params, &errmsg))
3793                 die(_("Failed to parse --dirstat/-X option parameter:\n%s"),
3794                     errmsg.buf);
3795         strbuf_release(&errmsg);
3796         /*
3797          * The caller knows a dirstat-related option is given from the command
3798          * line; allow it to say "return this_function();"
3799          */
3800         options->output_format |= DIFF_FORMAT_DIRSTAT;
3801         return 1;
3802 }
3803
3804 static int parse_submodule_opt(struct diff_options *options, const char *value)
3805 {
3806         if (parse_submodule_params(options, value))
3807                 die(_("Failed to parse --submodule option parameter: '%s'"),
3808                         value);
3809         return 1;
3810 }
3811
3812 static const char diff_status_letters[] = {
3813         DIFF_STATUS_ADDED,
3814         DIFF_STATUS_COPIED,
3815         DIFF_STATUS_DELETED,
3816         DIFF_STATUS_MODIFIED,
3817         DIFF_STATUS_RENAMED,
3818         DIFF_STATUS_TYPE_CHANGED,
3819         DIFF_STATUS_UNKNOWN,
3820         DIFF_STATUS_UNMERGED,
3821         DIFF_STATUS_FILTER_AON,
3822         DIFF_STATUS_FILTER_BROKEN,
3823         '\0',
3824 };
3825
3826 static unsigned int filter_bit['Z' + 1];
3827
3828 static void prepare_filter_bits(void)
3829 {
3830         int i;
3831
3832         if (!filter_bit[DIFF_STATUS_ADDED]) {
3833                 for (i = 0; diff_status_letters[i]; i++)
3834                         filter_bit[(int) diff_status_letters[i]] = (1 << i);
3835         }
3836 }
3837
3838 static unsigned filter_bit_tst(char status, const struct diff_options *opt)
3839 {
3840         return opt->filter & filter_bit[(int) status];
3841 }
3842
3843 static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
3844 {
3845         int i, optch;
3846
3847         prepare_filter_bits();
3848
3849         /*
3850          * If there is a negation e.g. 'd' in the input, and we haven't
3851          * initialized the filter field with another --diff-filter, start
3852          * from full set of bits, except for AON.
3853          */
3854         if (!opt->filter) {
3855                 for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3856                         if (optch < 'a' || 'z' < optch)
3857                                 continue;
3858                         opt->filter = (1 << (ARRAY_SIZE(diff_status_letters) - 1)) - 1;
3859                         opt->filter &= ~filter_bit[DIFF_STATUS_FILTER_AON];
3860                         break;
3861                 }
3862         }
3863
3864         for (i = 0; (optch = optarg[i]) != '\0'; i++) {
3865                 unsigned int bit;
3866                 int negate;
3867
3868                 if ('a' <= optch && optch <= 'z') {
3869                         negate = 1;
3870                         optch = toupper(optch);
3871                 } else {
3872                         negate = 0;
3873                 }
3874
3875                 bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
3876                 if (!bit)
3877                         return optarg[i];
3878                 if (negate)
3879                         opt->filter &= ~bit;
3880                 else
3881                         opt->filter |= bit;
3882         }
3883         return 0;
3884 }
3885
3886 static void enable_patch_output(int *fmt) {
3887         *fmt &= ~DIFF_FORMAT_NO_OUTPUT;
3888         *fmt |= DIFF_FORMAT_PATCH;
3889 }
3890
3891 static int parse_ws_error_highlight_opt(struct diff_options *opt, const char *arg)
3892 {
3893         int val = parse_ws_error_highlight(arg);
3894
3895         if (val < 0) {
3896                 error("unknown value after ws-error-highlight=%.*s",
3897                       -1 - val, arg);
3898                 return 0;
3899         }
3900         opt->ws_error_highlight = val;
3901         return 1;
3902 }
3903
3904 int diff_opt_parse(struct diff_options *options,
3905                    const char **av, int ac, const char *prefix)
3906 {
3907         const char *arg = av[0];
3908         const char *optarg;
3909         int argcount;
3910
3911         if (!prefix)
3912                 prefix = "";
3913
3914         /* Output format options */
3915         if (!strcmp(arg, "-p") || !strcmp(arg, "-u") || !strcmp(arg, "--patch")
3916             || opt_arg(arg, 'U', "unified", &options->context))
3917                 enable_patch_output(&options->output_format);
3918         else if (!strcmp(arg, "--raw"))
3919                 options->output_format |= DIFF_FORMAT_RAW;
3920         else if (!strcmp(arg, "--patch-with-raw")) {
3921                 enable_patch_output(&options->output_format);
3922                 options->output_format |= DIFF_FORMAT_RAW;
3923         } else if (!strcmp(arg, "--numstat"))
3924                 options->output_format |= DIFF_FORMAT_NUMSTAT;
3925         else if (!strcmp(arg, "--shortstat"))
3926                 options->output_format |= DIFF_FORMAT_SHORTSTAT;
3927         else if (!strcmp(arg, "-X") || !strcmp(arg, "--dirstat"))
3928                 return parse_dirstat_opt(options, "");
3929         else if (skip_prefix(arg, "-X", &arg))
3930                 return parse_dirstat_opt(options, arg);
3931         else if (skip_prefix(arg, "--dirstat=", &arg))
3932                 return parse_dirstat_opt(options, arg);
3933         else if (!strcmp(arg, "--cumulative"))
3934                 return parse_dirstat_opt(options, "cumulative");
3935         else if (!strcmp(arg, "--dirstat-by-file"))
3936                 return parse_dirstat_opt(options, "files");
3937         else if (skip_prefix(arg, "--dirstat-by-file=", &arg)) {
3938                 parse_dirstat_opt(options, "files");
3939                 return parse_dirstat_opt(options, arg);
3940         }
3941         else if (!strcmp(arg, "--check"))
3942                 options->output_format |= DIFF_FORMAT_CHECKDIFF;
3943         else if (!strcmp(arg, "--summary"))
3944                 options->output_format |= DIFF_FORMAT_SUMMARY;
3945         else if (!strcmp(arg, "--patch-with-stat")) {
3946                 enable_patch_output(&options->output_format);
3947                 options->output_format |= DIFF_FORMAT_DIFFSTAT;
3948         } else if (!strcmp(arg, "--name-only"))
3949                 options->output_format |= DIFF_FORMAT_NAME;
3950         else if (!strcmp(arg, "--name-status"))
3951                 options->output_format |= DIFF_FORMAT_NAME_STATUS;
3952         else if (!strcmp(arg, "-s") || !strcmp(arg, "--no-patch"))
3953                 options->output_format |= DIFF_FORMAT_NO_OUTPUT;
3954         else if (starts_with(arg, "--stat"))
3955                 /* --stat, --stat-width, --stat-name-width, or --stat-count */
3956                 return stat_opt(options, av);
3957
3958         /* renames options */
3959         else if (starts_with(arg, "-B") || starts_with(arg, "--break-rewrites=") ||
3960                  !strcmp(arg, "--break-rewrites")) {
3961                 if ((options->break_opt = diff_scoreopt_parse(arg)) == -1)
3962                         return error("invalid argument to -B: %s", arg+2);
3963         }
3964         else if (starts_with(arg, "-M") || starts_with(arg, "--find-renames=") ||
3965                  !strcmp(arg, "--find-renames")) {
3966                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3967                         return error("invalid argument to -M: %s", arg+2);
3968                 options->detect_rename = DIFF_DETECT_RENAME;
3969         }
3970         else if (!strcmp(arg, "-D") || !strcmp(arg, "--irreversible-delete")) {
3971                 options->irreversible_delete = 1;
3972         }
3973         else if (starts_with(arg, "-C") || starts_with(arg, "--find-copies=") ||
3974                  !strcmp(arg, "--find-copies")) {
3975                 if (options->detect_rename == DIFF_DETECT_COPY)
3976                         DIFF_OPT_SET(options, FIND_COPIES_HARDER);
3977                 if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
3978                         return error("invalid argument to -C: %s", arg+2);
3979                 options->detect_rename = DIFF_DETECT_COPY;
3980         }
3981         else if (!strcmp(arg, "--no-renames"))
3982                 options->detect_rename = 0;
3983         else if (!strcmp(arg, "--rename-empty"))
3984                 DIFF_OPT_SET(options, RENAME_EMPTY);
3985         else if (!strcmp(arg, "--no-rename-empty"))
3986                 DIFF_OPT_CLR(options, RENAME_EMPTY);
3987         else if (!strcmp(arg, "--relative"))
3988                 DIFF_OPT_SET(options, RELATIVE_NAME);
3989         else if (skip_prefix(arg, "--relative=", &arg)) {
3990                 DIFF_OPT_SET(options, RELATIVE_NAME);
3991                 options->prefix = arg;
3992         }
3993
3994         /* xdiff options */
3995         else if (!strcmp(arg, "--minimal"))
3996                 DIFF_XDL_SET(options, NEED_MINIMAL);
3997         else if (!strcmp(arg, "--no-minimal"))
3998                 DIFF_XDL_CLR(options, NEED_MINIMAL);
3999         else if (!strcmp(arg, "-w") || !strcmp(arg, "--ignore-all-space"))
4000                 DIFF_XDL_SET(options, IGNORE_WHITESPACE);
4001         else if (!strcmp(arg, "-b") || !strcmp(arg, "--ignore-space-change"))
4002                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_CHANGE);
4003         else if (!strcmp(arg, "--ignore-space-at-eol"))
4004                 DIFF_XDL_SET(options, IGNORE_WHITESPACE_AT_EOL);
4005         else if (!strcmp(arg, "--ignore-blank-lines"))
4006                 DIFF_XDL_SET(options, IGNORE_BLANK_LINES);
4007         else if (!strcmp(arg, "--indent-heuristic"))
4008                 DIFF_XDL_SET(options, INDENT_HEURISTIC);
4009         else if (!strcmp(arg, "--no-indent-heuristic"))
4010                 DIFF_XDL_CLR(options, INDENT_HEURISTIC);
4011         else if (!strcmp(arg, "--patience"))
4012                 options->xdl_opts = DIFF_WITH_ALG(options, PATIENCE_DIFF);
4013         else if (!strcmp(arg, "--histogram"))
4014                 options->xdl_opts = DIFF_WITH_ALG(options, HISTOGRAM_DIFF);
4015         else if ((argcount = parse_long_opt("diff-algorithm", av, &optarg))) {
4016                 long value = parse_algorithm_value(optarg);
4017                 if (value < 0)
4018                         return error("option diff-algorithm accepts \"myers\", "
4019                                      "\"minimal\", \"patience\" and \"histogram\"");
4020                 /* clear out previous settings */
4021                 DIFF_XDL_CLR(options, NEED_MINIMAL);
4022                 options->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
4023                 options->xdl_opts |= value;
4024                 return argcount;
4025         }
4026
4027         /* flags options */
4028         else if (!strcmp(arg, "--binary")) {
4029                 enable_patch_output(&options->output_format);
4030                 DIFF_OPT_SET(options, BINARY);
4031         }
4032         else if (!strcmp(arg, "--full-index"))
4033                 DIFF_OPT_SET(options, FULL_INDEX);
4034         else if (!strcmp(arg, "-a") || !strcmp(arg, "--text"))
4035                 DIFF_OPT_SET(options, TEXT);
4036         else if (!strcmp(arg, "-R"))
4037                 DIFF_OPT_SET(options, REVERSE_DIFF);
4038         else if (!strcmp(arg, "--find-copies-harder"))
4039                 DIFF_OPT_SET(options, FIND_COPIES_HARDER);
4040         else if (!strcmp(arg, "--follow"))
4041                 DIFF_OPT_SET(options, FOLLOW_RENAMES);
4042         else if (!strcmp(arg, "--no-follow")) {
4043                 DIFF_OPT_CLR(options, FOLLOW_RENAMES);
4044                 DIFF_OPT_CLR(options, DEFAULT_FOLLOW_RENAMES);
4045         } else if (!strcmp(arg, "--color"))
4046                 options->use_color = 1;
4047         else if (skip_prefix(arg, "--color=", &arg)) {
4048                 int value = git_config_colorbool(NULL, arg);
4049                 if (value < 0)
4050                         return error("option `color' expects \"always\", \"auto\", or \"never\"");
4051                 options->use_color = value;
4052         }
4053         else if (!strcmp(arg, "--no-color"))
4054                 options->use_color = 0;
4055         else if (!strcmp(arg, "--color-words")) {
4056                 options->use_color = 1;
4057                 options->word_diff = DIFF_WORDS_COLOR;
4058         }
4059         else if (skip_prefix(arg, "--color-words=", &arg)) {
4060                 options->use_color = 1;
4061                 options->word_diff = DIFF_WORDS_COLOR;
4062                 options->word_regex = arg;
4063         }
4064         else if (!strcmp(arg, "--word-diff")) {
4065                 if (options->word_diff == DIFF_WORDS_NONE)
4066                         options->word_diff = DIFF_WORDS_PLAIN;
4067         }
4068         else if (skip_prefix(arg, "--word-diff=", &arg)) {
4069                 if (!strcmp(arg, "plain"))
4070                         options->word_diff = DIFF_WORDS_PLAIN;
4071                 else if (!strcmp(arg, "color")) {
4072                         options->use_color = 1;
4073                         options->word_diff = DIFF_WORDS_COLOR;
4074                 }
4075                 else if (!strcmp(arg, "porcelain"))
4076                         options->word_diff = DIFF_WORDS_PORCELAIN;
4077                 else if (!strcmp(arg, "none"))
4078                         options->word_diff = DIFF_WORDS_NONE;
4079                 else
4080                         die("bad --word-diff argument: %s", arg);
4081         }
4082         else if ((argcount = parse_long_opt("word-diff-regex", av, &optarg))) {
4083                 if (options->word_diff == DIFF_WORDS_NONE)
4084                         options->word_diff = DIFF_WORDS_PLAIN;
4085                 options->word_regex = optarg;
4086                 return argcount;
4087         }
4088         else if (!strcmp(arg, "--exit-code"))
4089                 DIFF_OPT_SET(options, EXIT_WITH_STATUS);
4090         else if (!strcmp(arg, "--quiet"))
4091                 DIFF_OPT_SET(options, QUICK);
4092         else if (!strcmp(arg, "--ext-diff"))
4093                 DIFF_OPT_SET(options, ALLOW_EXTERNAL);
4094         else if (!strcmp(arg, "--no-ext-diff"))
4095                 DIFF_OPT_CLR(options, ALLOW_EXTERNAL);
4096         else if (!strcmp(arg, "--textconv"))
4097                 DIFF_OPT_SET(options, ALLOW_TEXTCONV);
4098         else if (!strcmp(arg, "--no-textconv"))
4099                 DIFF_OPT_CLR(options, ALLOW_TEXTCONV);
4100         else if (!strcmp(arg, "--ignore-submodules")) {
4101                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4102                 handle_ignore_submodules_arg(options, "all");
4103         } else if (skip_prefix(arg, "--ignore-submodules=", &arg)) {
4104                 DIFF_OPT_SET(options, OVERRIDE_SUBMODULE_CONFIG);
4105                 handle_ignore_submodules_arg(options, arg);
4106         } else if (!strcmp(arg, "--submodule"))
4107                 options->submodule_format = DIFF_SUBMODULE_LOG;
4108         else if (skip_prefix(arg, "--submodule=", &arg))
4109                 return parse_submodule_opt(options, arg);
4110         else if (skip_prefix(arg, "--ws-error-highlight=", &arg))
4111                 return parse_ws_error_highlight_opt(options, arg);
4112         else if (!strcmp(arg, "--ita-invisible-in-index"))
4113                 options->ita_invisible_in_index = 1;
4114         else if (!strcmp(arg, "--ita-visible-in-index"))
4115                 options->ita_invisible_in_index = 0;
4116
4117         /* misc options */
4118         else if (!strcmp(arg, "-z"))
4119                 options->line_termination = 0;
4120         else if ((argcount = short_opt('l', av, &optarg))) {
4121                 options->rename_limit = strtoul(optarg, NULL, 10);
4122                 return argcount;
4123         }
4124         else if ((argcount = short_opt('S', av, &optarg))) {
4125                 options->pickaxe = optarg;
4126                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_S;
4127                 return argcount;
4128         } else if ((argcount = short_opt('G', av, &optarg))) {
4129                 options->pickaxe = optarg;
4130                 options->pickaxe_opts |= DIFF_PICKAXE_KIND_G;
4131                 return argcount;
4132         }
4133         else if (!strcmp(arg, "--pickaxe-all"))
4134                 options->pickaxe_opts |= DIFF_PICKAXE_ALL;
4135         else if (!strcmp(arg, "--pickaxe-regex"))
4136                 options->pickaxe_opts |= DIFF_PICKAXE_REGEX;
4137         else if ((argcount = short_opt('O', av, &optarg))) {
4138                 options->orderfile = prefix_filename(prefix, optarg);
4139                 return argcount;
4140         }
4141         else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
4142                 int offending = parse_diff_filter_opt(optarg, options);
4143                 if (offending)
4144                         die("unknown change class '%c' in --diff-filter=%s",
4145                             offending, optarg);
4146                 return argcount;
4147         }
4148         else if (!strcmp(arg, "--no-abbrev"))
4149                 options->abbrev = 0;
4150         else if (!strcmp(arg, "--abbrev"))
4151                 options->abbrev = DEFAULT_ABBREV;
4152         else if (skip_prefix(arg, "--abbrev=", &arg)) {
4153                 options->abbrev = strtoul(arg, NULL, 10);
4154                 if (options->abbrev < MINIMUM_ABBREV)
4155                         options->abbrev = MINIMUM_ABBREV;
4156                 else if (40 < options->abbrev)
4157                         options->abbrev = 40;
4158         }
4159         else if ((argcount = parse_long_opt("src-prefix", av, &optarg))) {
4160                 options->a_prefix = optarg;
4161                 return argcount;
4162         }
4163         else if ((argcount = parse_long_opt("line-prefix", av, &optarg))) {
4164                 options->line_prefix = optarg;
4165                 options->line_prefix_length = strlen(options->line_prefix);
4166                 graph_setup_line_prefix(options);
4167                 return argcount;
4168         }
4169         else if ((argcount = parse_long_opt("dst-prefix", av, &optarg))) {
4170                 options->b_prefix = optarg;
4171                 return argcount;
4172         }
4173         else if (!strcmp(arg, "--no-prefix"))
4174                 options->a_prefix = options->b_prefix = "";
4175         else if (opt_arg(arg, '\0', "inter-hunk-context",
4176                          &options->interhunkcontext))
4177                 ;
4178         else if (!strcmp(arg, "-W"))
4179                 DIFF_OPT_SET(options, FUNCCONTEXT);
4180         else if (!strcmp(arg, "--function-context"))
4181                 DIFF_OPT_SET(options, FUNCCONTEXT);
4182         else if (!strcmp(arg, "--no-function-context"))
4183                 DIFF_OPT_CLR(options, FUNCCONTEXT);
4184         else if ((argcount = parse_long_opt("output", av, &optarg))) {
4185                 char *path = prefix_filename(prefix, optarg);
4186                 options->file = xfopen(path, "w");
4187                 options->close_file = 1;
4188                 if (options->use_color != GIT_COLOR_ALWAYS)
4189                         options->use_color = GIT_COLOR_NEVER;
4190                 free(path);
4191                 return argcount;
4192         } else
4193                 return 0;
4194         return 1;
4195 }
4196
4197 int parse_rename_score(const char **cp_p)
4198 {
4199         unsigned long num, scale;
4200         int ch, dot;
4201         const char *cp = *cp_p;
4202
4203         num = 0;
4204         scale = 1;
4205         dot = 0;
4206         for (;;) {
4207                 ch = *cp;
4208                 if ( !dot && ch == '.' ) {
4209                         scale = 1;
4210                         dot = 1;
4211                 } else if ( ch == '%' ) {
4212                         scale = dot ? scale*100 : 100;
4213                         cp++;   /* % is always at the end */
4214                         break;
4215                 } else if ( ch >= '0' && ch <= '9' ) {
4216                         if ( scale < 100000 ) {
4217                                 scale *= 10;
4218                                 num = (num*10) + (ch-'0');
4219                         }
4220                 } else {
4221                         break;
4222                 }
4223                 cp++;
4224         }
4225         *cp_p = cp;
4226
4227         /* user says num divided by scale and we say internally that
4228          * is MAX_SCORE * num / scale.
4229          */
4230         return (int)((num >= scale) ? MAX_SCORE : (MAX_SCORE * num / scale));
4231 }
4232
4233 static int diff_scoreopt_parse(const char *opt)
4234 {
4235         int opt1, opt2, cmd;
4236
4237         if (*opt++ != '-')
4238                 return -1;
4239         cmd = *opt++;
4240         if (cmd == '-') {
4241                 /* convert the long-form arguments into short-form versions */
4242                 if (skip_prefix(opt, "break-rewrites", &opt)) {
4243                         if (*opt == 0 || *opt++ == '=')
4244                                 cmd = 'B';
4245                 } else if (skip_prefix(opt, "find-copies", &opt)) {
4246                         if (*opt == 0 || *opt++ == '=')
4247                                 cmd = 'C';
4248                 } else if (skip_prefix(opt, "find-renames", &opt)) {
4249                         if (*opt == 0 || *opt++ == '=')
4250                                 cmd = 'M';
4251                 }
4252         }
4253         if (cmd != 'M' && cmd != 'C' && cmd != 'B')
4254                 return -1; /* that is not a -M, -C, or -B option */
4255
4256         opt1 = parse_rename_score(&opt);
4257         if (cmd != 'B')
4258                 opt2 = 0;
4259         else {
4260                 if (*opt == 0)
4261                         opt2 = 0;
4262                 else if (*opt != '/')
4263                         return -1; /* we expect -B80/99 or -B80 */
4264                 else {
4265                         opt++;
4266                         opt2 = parse_rename_score(&opt);
4267                 }
4268         }
4269         if (*opt != 0)
4270                 return -1;
4271         return opt1 | (opt2 << 16);
4272 }
4273
4274 struct diff_queue_struct diff_queued_diff;
4275
4276 void diff_q(struct diff_queue_struct *queue, struct diff_filepair *dp)
4277 {
4278         ALLOC_GROW(queue->queue, queue->nr + 1, queue->alloc);
4279         queue->queue[queue->nr++] = dp;
4280 }
4281
4282 struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
4283                                  struct diff_filespec *one,
4284                                  struct diff_filespec *two)
4285 {
4286         struct diff_filepair *dp = xcalloc(1, sizeof(*dp));
4287         dp->one = one;
4288         dp->two = two;
4289         if (queue)
4290                 diff_q(queue, dp);
4291         return dp;
4292 }
4293
4294 void diff_free_filepair(struct diff_filepair *p)
4295 {
4296         free_filespec(p->one);
4297         free_filespec(p->two);
4298         free(p);
4299 }
4300
4301 const char *diff_aligned_abbrev(const struct object_id *oid, int len)
4302 {
4303         int abblen;
4304         const char *abbrev;
4305
4306         if (len == GIT_SHA1_HEXSZ)
4307                 return oid_to_hex(oid);
4308
4309         abbrev = diff_abbrev_oid(oid, len);
4310         abblen = strlen(abbrev);
4311
4312         /*
4313          * In well-behaved cases, where the abbbreviated result is the
4314          * same as the requested length, append three dots after the
4315          * abbreviation (hence the whole logic is limited to the case
4316          * where abblen < 37); when the actual abbreviated result is a
4317          * bit longer than the requested length, we reduce the number
4318          * of dots so that they match the well-behaved ones.  However,
4319          * if the actual abbreviation is longer than the requested
4320          * length by more than three, we give up on aligning, and add
4321          * three dots anyway, to indicate that the output is not the
4322          * full object name.  Yes, this may be suboptimal, but this
4323          * appears only in "diff --raw --abbrev" output and it is not
4324          * worth the effort to change it now.  Note that this would
4325          * likely to work fine when the automatic sizing of default
4326          * abbreviation length is used--we would be fed -1 in "len" in
4327          * that case, and will end up always appending three-dots, but
4328          * the automatic sizing is supposed to give abblen that ensures
4329          * uniqueness across all objects (statistically speaking).
4330          */
4331         if (abblen < GIT_SHA1_HEXSZ - 3) {
4332                 static char hex[GIT_MAX_HEXSZ + 1];
4333                 if (len < abblen && abblen <= len + 2)
4334                         xsnprintf(hex, sizeof(hex), "%s%.*s", abbrev, len+3-abblen, "..");
4335                 else
4336                         xsnprintf(hex, sizeof(hex), "%s...", abbrev);
4337                 return hex;
4338         }
4339
4340         return oid_to_hex(oid);
4341 }
4342
4343 static void diff_flush_raw(struct diff_filepair *p, struct diff_options *opt)
4344 {
4345         int line_termination = opt->line_termination;
4346         int inter_name_termination = line_termination ? '\t' : '\0';
4347
4348         fprintf(opt->file, "%s", diff_line_prefix(opt));
4349         if (!(opt->output_format & DIFF_FORMAT_NAME_STATUS)) {
4350                 fprintf(opt->file, ":%06o %06o %s ", p->one->mode, p->two->mode,
4351                         diff_aligned_abbrev(&p->one->oid, opt->abbrev));
4352                 fprintf(opt->file, "%s ",
4353                         diff_aligned_abbrev(&p->two->oid, opt->abbrev));
4354         }
4355         if (p->score) {
4356                 fprintf(opt->file, "%c%03d%c", p->status, similarity_index(p),
4357                         inter_name_termination);
4358         } else {
4359                 fprintf(opt->file, "%c%c", p->status, inter_name_termination);
4360         }
4361
4362         if (p->status == DIFF_STATUS_COPIED ||
4363             p->status == DIFF_STATUS_RENAMED) {
4364                 const char *name_a, *name_b;
4365                 name_a = p->one->path;
4366                 name_b = p->two->path;
4367                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4368                 write_name_quoted(name_a, opt->file, inter_name_termination);
4369                 write_name_quoted(name_b, opt->file, line_termination);
4370         } else {
4371                 const char *name_a, *name_b;
4372                 name_a = p->one->mode ? p->one->path : p->two->path;
4373                 name_b = NULL;
4374                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4375                 write_name_quoted(name_a, opt->file, line_termination);
4376         }
4377 }
4378
4379 int diff_unmodified_pair(struct diff_filepair *p)
4380 {
4381         /* This function is written stricter than necessary to support
4382          * the currently implemented transformers, but the idea is to
4383          * let transformers to produce diff_filepairs any way they want,
4384          * and filter and clean them up here before producing the output.
4385          */
4386         struct diff_filespec *one = p->one, *two = p->two;
4387
4388         if (DIFF_PAIR_UNMERGED(p))
4389                 return 0; /* unmerged is interesting */
4390
4391         /* deletion, addition, mode or type change
4392          * and rename are all interesting.
4393          */
4394         if (DIFF_FILE_VALID(one) != DIFF_FILE_VALID(two) ||
4395             DIFF_PAIR_MODE_CHANGED(p) ||
4396             strcmp(one->path, two->path))
4397                 return 0;
4398
4399         /* both are valid and point at the same path.  that is, we are
4400          * dealing with a change.
4401          */
4402         if (one->oid_valid && two->oid_valid &&
4403             !oidcmp(&one->oid, &two->oid) &&
4404             !one->dirty_submodule && !two->dirty_submodule)
4405                 return 1; /* no change */
4406         if (!one->oid_valid && !two->oid_valid)
4407                 return 1; /* both look at the same file on the filesystem. */
4408         return 0;
4409 }
4410
4411 static void diff_flush_patch(struct diff_filepair *p, struct diff_options *o)
4412 {
4413         if (diff_unmodified_pair(p))
4414                 return;
4415
4416         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4417             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4418                 return; /* no tree diffs in patch format */
4419
4420         run_diff(p, o);
4421 }
4422
4423 static void diff_flush_stat(struct diff_filepair *p, struct diff_options *o,
4424                             struct diffstat_t *diffstat)
4425 {
4426         if (diff_unmodified_pair(p))
4427                 return;
4428
4429         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4430             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4431                 return; /* no useful stat for tree diffs */
4432
4433         run_diffstat(p, o, diffstat);
4434 }
4435
4436 static void diff_flush_checkdiff(struct diff_filepair *p,
4437                 struct diff_options *o)
4438 {
4439         if (diff_unmodified_pair(p))
4440                 return;
4441
4442         if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4443             (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4444                 return; /* nothing to check in tree diffs */
4445
4446         run_checkdiff(p, o);
4447 }
4448
4449 int diff_queue_is_empty(void)
4450 {
4451         struct diff_queue_struct *q = &diff_queued_diff;
4452         int i;
4453         for (i = 0; i < q->nr; i++)
4454                 if (!diff_unmodified_pair(q->queue[i]))
4455                         return 0;
4456         return 1;
4457 }
4458
4459 #if DIFF_DEBUG
4460 void diff_debug_filespec(struct diff_filespec *s, int x, const char *one)
4461 {
4462         fprintf(stderr, "queue[%d] %s (%s) %s %06o %s\n",
4463                 x, one ? one : "",
4464                 s->path,
4465                 DIFF_FILE_VALID(s) ? "valid" : "invalid",
4466                 s->mode,
4467                 s->oid_valid ? oid_to_hex(&s->oid) : "");
4468         fprintf(stderr, "queue[%d] %s size %lu\n",
4469                 x, one ? one : "",
4470                 s->size);
4471 }
4472
4473 void diff_debug_filepair(const struct diff_filepair *p, int i)
4474 {
4475         diff_debug_filespec(p->one, i, "one");
4476         diff_debug_filespec(p->two, i, "two");
4477         fprintf(stderr, "score %d, status %c rename_used %d broken %d\n",
4478                 p->score, p->status ? p->status : '?',
4479                 p->one->rename_used, p->broken_pair);
4480 }
4481
4482 void diff_debug_queue(const char *msg, struct diff_queue_struct *q)
4483 {
4484         int i;
4485         if (msg)
4486                 fprintf(stderr, "%s\n", msg);
4487         fprintf(stderr, "q->nr = %d\n", q->nr);
4488         for (i = 0; i < q->nr; i++) {
4489                 struct diff_filepair *p = q->queue[i];
4490                 diff_debug_filepair(p, i);
4491         }
4492 }
4493 #endif
4494
4495 static void diff_resolve_rename_copy(void)
4496 {
4497         int i;
4498         struct diff_filepair *p;
4499         struct diff_queue_struct *q = &diff_queued_diff;
4500
4501         diff_debug_queue("resolve-rename-copy", q);
4502
4503         for (i = 0; i < q->nr; i++) {
4504                 p = q->queue[i];
4505                 p->status = 0; /* undecided */
4506                 if (DIFF_PAIR_UNMERGED(p))
4507                         p->status = DIFF_STATUS_UNMERGED;
4508                 else if (!DIFF_FILE_VALID(p->one))
4509                         p->status = DIFF_STATUS_ADDED;
4510                 else if (!DIFF_FILE_VALID(p->two))
4511                         p->status = DIFF_STATUS_DELETED;
4512                 else if (DIFF_PAIR_TYPE_CHANGED(p))
4513                         p->status = DIFF_STATUS_TYPE_CHANGED;
4514
4515                 /* from this point on, we are dealing with a pair
4516                  * whose both sides are valid and of the same type, i.e.
4517                  * either in-place edit or rename/copy edit.
4518                  */
4519                 else if (DIFF_PAIR_RENAME(p)) {
4520                         /*
4521                          * A rename might have re-connected a broken
4522                          * pair up, causing the pathnames to be the
4523                          * same again. If so, that's not a rename at
4524                          * all, just a modification..
4525                          *
4526                          * Otherwise, see if this source was used for
4527                          * multiple renames, in which case we decrement
4528                          * the count, and call it a copy.
4529                          */
4530                         if (!strcmp(p->one->path, p->two->path))
4531                                 p->status = DIFF_STATUS_MODIFIED;
4532                         else if (--p->one->rename_used > 0)
4533                                 p->status = DIFF_STATUS_COPIED;
4534                         else
4535                                 p->status = DIFF_STATUS_RENAMED;
4536                 }
4537                 else if (oidcmp(&p->one->oid, &p->two->oid) ||
4538                          p->one->mode != p->two->mode ||
4539                          p->one->dirty_submodule ||
4540                          p->two->dirty_submodule ||
4541                          is_null_oid(&p->one->oid))
4542                         p->status = DIFF_STATUS_MODIFIED;
4543                 else {
4544                         /* This is a "no-change" entry and should not
4545                          * happen anymore, but prepare for broken callers.
4546                          */
4547                         error("feeding unmodified %s to diffcore",
4548                               p->one->path);
4549                         p->status = DIFF_STATUS_UNKNOWN;
4550                 }
4551         }
4552         diff_debug_queue("resolve-rename-copy done", q);
4553 }
4554
4555 static int check_pair_status(struct diff_filepair *p)
4556 {
4557         switch (p->status) {
4558         case DIFF_STATUS_UNKNOWN:
4559                 return 0;
4560         case 0:
4561                 die("internal error in diff-resolve-rename-copy");
4562         default:
4563                 return 1;
4564         }
4565 }
4566
4567 static void flush_one_pair(struct diff_filepair *p, struct diff_options *opt)
4568 {
4569         int fmt = opt->output_format;
4570
4571         if (fmt & DIFF_FORMAT_CHECKDIFF)
4572                 diff_flush_checkdiff(p, opt);
4573         else if (fmt & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS))
4574                 diff_flush_raw(p, opt);
4575         else if (fmt & DIFF_FORMAT_NAME) {
4576                 const char *name_a, *name_b;
4577                 name_a = p->two->path;
4578                 name_b = NULL;
4579                 strip_prefix(opt->prefix_length, &name_a, &name_b);
4580                 fprintf(opt->file, "%s", diff_line_prefix(opt));
4581                 write_name_quoted(name_a, opt->file, opt->line_termination);
4582         }
4583 }
4584
4585 static void show_file_mode_name(FILE *file, const char *newdelete, struct diff_filespec *fs)
4586 {
4587         if (fs->mode)
4588                 fprintf(file, " %s mode %06o ", newdelete, fs->mode);
4589         else
4590                 fprintf(file, " %s ", newdelete);
4591         write_name_quoted(fs->path, file, '\n');
4592 }
4593
4594
4595 static void show_mode_change(FILE *file, struct diff_filepair *p, int show_name,
4596                 const char *line_prefix)
4597 {
4598         if (p->one->mode && p->two->mode && p->one->mode != p->two->mode) {
4599                 fprintf(file, "%s mode change %06o => %06o%c", line_prefix, p->one->mode,
4600                         p->two->mode, show_name ? ' ' : '\n');
4601                 if (show_name) {
4602                         write_name_quoted(p->two->path, file, '\n');
4603                 }
4604         }
4605 }
4606
4607 static void show_rename_copy(FILE *file, const char *renamecopy, struct diff_filepair *p,
4608                         const char *line_prefix)
4609 {
4610         char *names = pprint_rename(p->one->path, p->two->path);
4611
4612         fprintf(file, " %s %s (%d%%)\n", renamecopy, names, similarity_index(p));
4613         free(names);
4614         show_mode_change(file, p, 0, line_prefix);
4615 }
4616
4617 static void diff_summary(struct diff_options *opt, struct diff_filepair *p)
4618 {
4619         FILE *file = opt->file;
4620         const char *line_prefix = diff_line_prefix(opt);
4621
4622         switch(p->status) {
4623         case DIFF_STATUS_DELETED:
4624                 fputs(line_prefix, file);
4625                 show_file_mode_name(file, "delete", p->one);
4626                 break;
4627         case DIFF_STATUS_ADDED:
4628                 fputs(line_prefix, file);
4629                 show_file_mode_name(file, "create", p->two);
4630                 break;
4631         case DIFF_STATUS_COPIED:
4632                 fputs(line_prefix, file);
4633                 show_rename_copy(file, "copy", p, line_prefix);
4634                 break;
4635         case DIFF_STATUS_RENAMED:
4636                 fputs(line_prefix, file);
4637                 show_rename_copy(file, "rename", p, line_prefix);
4638                 break;
4639         default:
4640                 if (p->score) {
4641                         fprintf(file, "%s rewrite ", line_prefix);
4642                         write_name_quoted(p->two->path, file, ' ');
4643                         fprintf(file, "(%d%%)\n", similarity_index(p));
4644                 }
4645                 show_mode_change(file, p, !p->score, line_prefix);
4646                 break;
4647         }
4648 }
4649
4650 struct patch_id_t {
4651         git_SHA_CTX *ctx;
4652         int patchlen;
4653 };
4654
4655 static int remove_space(char *line, int len)
4656 {
4657         int i;
4658         char *dst = line;
4659         unsigned char c;
4660
4661         for (i = 0; i < len; i++)
4662                 if (!isspace((c = line[i])))
4663                         *dst++ = c;
4664
4665         return dst - line;
4666 }
4667
4668 static void patch_id_consume(void *priv, char *line, unsigned long len)
4669 {
4670         struct patch_id_t *data = priv;
4671         int new_len;
4672
4673         /* Ignore line numbers when computing the SHA1 of the patch */
4674         if (starts_with(line, "@@ -"))
4675                 return;
4676
4677         new_len = remove_space(line, len);
4678
4679         git_SHA1_Update(data->ctx, line, new_len);
4680         data->patchlen += new_len;
4681 }
4682
4683 static void patch_id_add_string(git_SHA_CTX *ctx, const char *str)
4684 {
4685         git_SHA1_Update(ctx, str, strlen(str));
4686 }
4687
4688 static void patch_id_add_mode(git_SHA_CTX *ctx, unsigned mode)
4689 {
4690         /* large enough for 2^32 in octal */
4691         char buf[12];
4692         int len = xsnprintf(buf, sizeof(buf), "%06o", mode);
4693         git_SHA1_Update(ctx, buf, len);
4694 }
4695
4696 /* returns 0 upon success, and writes result into sha1 */
4697 static int diff_get_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4698 {
4699         struct diff_queue_struct *q = &diff_queued_diff;
4700         int i;
4701         git_SHA_CTX ctx;
4702         struct patch_id_t data;
4703
4704         git_SHA1_Init(&ctx);
4705         memset(&data, 0, sizeof(struct patch_id_t));
4706         data.ctx = &ctx;
4707
4708         for (i = 0; i < q->nr; i++) {
4709                 xpparam_t xpp;
4710                 xdemitconf_t xecfg;
4711                 mmfile_t mf1, mf2;
4712                 struct diff_filepair *p = q->queue[i];
4713                 int len1, len2;
4714
4715                 memset(&xpp, 0, sizeof(xpp));
4716                 memset(&xecfg, 0, sizeof(xecfg));
4717                 if (p->status == 0)
4718                         return error("internal diff status error");
4719                 if (p->status == DIFF_STATUS_UNKNOWN)
4720                         continue;
4721                 if (diff_unmodified_pair(p))
4722                         continue;
4723                 if ((DIFF_FILE_VALID(p->one) && S_ISDIR(p->one->mode)) ||
4724                     (DIFF_FILE_VALID(p->two) && S_ISDIR(p->two->mode)))
4725                         continue;
4726                 if (DIFF_PAIR_UNMERGED(p))
4727                         continue;
4728
4729                 diff_fill_oid_info(p->one);
4730                 diff_fill_oid_info(p->two);
4731
4732                 len1 = remove_space(p->one->path, strlen(p->one->path));
4733                 len2 = remove_space(p->two->path, strlen(p->two->path));
4734                 patch_id_add_string(&ctx, "diff--git");
4735                 patch_id_add_string(&ctx, "a/");
4736                 git_SHA1_Update(&ctx, p->one->path, len1);
4737                 patch_id_add_string(&ctx, "b/");
4738                 git_SHA1_Update(&ctx, p->two->path, len2);
4739
4740                 if (p->one->mode == 0) {
4741                         patch_id_add_string(&ctx, "newfilemode");
4742                         patch_id_add_mode(&ctx, p->two->mode);
4743                         patch_id_add_string(&ctx, "---/dev/null");
4744                         patch_id_add_string(&ctx, "+++b/");
4745                         git_SHA1_Update(&ctx, p->two->path, len2);
4746                 } else if (p->two->mode == 0) {
4747                         patch_id_add_string(&ctx, "deletedfilemode");
4748                         patch_id_add_mode(&ctx, p->one->mode);
4749                         patch_id_add_string(&ctx, "---a/");
4750                         git_SHA1_Update(&ctx, p->one->path, len1);
4751                         patch_id_add_string(&ctx, "+++/dev/null");
4752                 } else {
4753                         patch_id_add_string(&ctx, "---a/");
4754                         git_SHA1_Update(&ctx, p->one->path, len1);
4755                         patch_id_add_string(&ctx, "+++b/");
4756                         git_SHA1_Update(&ctx, p->two->path, len2);
4757                 }
4758
4759                 if (diff_header_only)
4760                         continue;
4761
4762                 if (fill_mmfile(&mf1, p->one) < 0 ||
4763                     fill_mmfile(&mf2, p->two) < 0)
4764                         return error("unable to read files to diff");
4765
4766                 if (diff_filespec_is_binary(p->one) ||
4767                     diff_filespec_is_binary(p->two)) {
4768                         git_SHA1_Update(&ctx, oid_to_hex(&p->one->oid),
4769                                         GIT_SHA1_HEXSZ);
4770                         git_SHA1_Update(&ctx, oid_to_hex(&p->two->oid),
4771                                         GIT_SHA1_HEXSZ);
4772                         continue;
4773                 }
4774
4775                 xpp.flags = 0;
4776                 xecfg.ctxlen = 3;
4777                 xecfg.flags = 0;
4778                 if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
4779                                   &xpp, &xecfg))
4780                         return error("unable to generate patch-id diff for %s",
4781                                      p->one->path);
4782         }
4783
4784         git_SHA1_Final(oid->hash, &ctx);
4785         return 0;
4786 }
4787
4788 int diff_flush_patch_id(struct diff_options *options, struct object_id *oid, int diff_header_only)
4789 {
4790         struct diff_queue_struct *q = &diff_queued_diff;
4791         int i;
4792         int result = diff_get_patch_id(options, oid, diff_header_only);
4793
4794         for (i = 0; i < q->nr; i++)
4795                 diff_free_filepair(q->queue[i]);
4796
4797         free(q->queue);
4798         DIFF_QUEUE_CLEAR(q);
4799
4800         return result;
4801 }
4802
4803 static int is_summary_empty(const struct diff_queue_struct *q)
4804 {
4805         int i;
4806
4807         for (i = 0; i < q->nr; i++) {
4808                 const struct diff_filepair *p = q->queue[i];
4809
4810                 switch (p->status) {
4811                 case DIFF_STATUS_DELETED:
4812                 case DIFF_STATUS_ADDED:
4813                 case DIFF_STATUS_COPIED:
4814                 case DIFF_STATUS_RENAMED:
4815                         return 0;
4816                 default:
4817                         if (p->score)
4818                                 return 0;
4819                         if (p->one->mode && p->two->mode &&
4820                             p->one->mode != p->two->mode)
4821                                 return 0;
4822                         break;
4823                 }
4824         }
4825         return 1;
4826 }
4827
4828 static const char rename_limit_warning[] =
4829 N_("inexact rename detection was skipped due to too many files.");
4830
4831 static const char degrade_cc_to_c_warning[] =
4832 N_("only found copies from modified paths due to too many files.");
4833
4834 static const char rename_limit_advice[] =
4835 N_("you may want to set your %s variable to at least "
4836    "%d and retry the command.");
4837
4838 void diff_warn_rename_limit(const char *varname, int needed, int degraded_cc)
4839 {
4840         if (degraded_cc)
4841                 warning(_(degrade_cc_to_c_warning));
4842         else if (needed)
4843                 warning(_(rename_limit_warning));
4844         else
4845                 return;
4846         if (0 < needed && needed < 32767)
4847                 warning(_(rename_limit_advice), varname, needed);
4848 }
4849
4850 static void diff_flush_patch_all_file_pairs(struct diff_options *o)
4851 {
4852         int i;
4853         struct diff_queue_struct *q = &diff_queued_diff;
4854
4855         if (WSEH_NEW & WS_RULE_MASK)
4856                 die("BUG: WS rules bit mask overlaps with diff symbol flags");
4857
4858         for (i = 0; i < q->nr; i++) {
4859                 struct diff_filepair *p = q->queue[i];
4860                 if (check_pair_status(p))
4861                         diff_flush_patch(p, o);
4862         }
4863 }
4864
4865 void diff_flush(struct diff_options *options)
4866 {
4867         struct diff_queue_struct *q = &diff_queued_diff;
4868         int i, output_format = options->output_format;
4869         int separator = 0;
4870         int dirstat_by_line = 0;
4871
4872         /*
4873          * Order: raw, stat, summary, patch
4874          * or:    name/name-status/checkdiff (other bits clear)
4875          */
4876         if (!q->nr)
4877                 goto free_queue;
4878
4879         if (output_format & (DIFF_FORMAT_RAW |
4880                              DIFF_FORMAT_NAME |
4881                              DIFF_FORMAT_NAME_STATUS |
4882                              DIFF_FORMAT_CHECKDIFF)) {
4883                 for (i = 0; i < q->nr; i++) {
4884                         struct diff_filepair *p = q->queue[i];
4885                         if (check_pair_status(p))
4886                                 flush_one_pair(p, options);
4887                 }
4888                 separator++;
4889         }
4890
4891         if (output_format & DIFF_FORMAT_DIRSTAT && DIFF_OPT_TST(options, DIRSTAT_BY_LINE))
4892                 dirstat_by_line = 1;
4893
4894         if (output_format & (DIFF_FORMAT_DIFFSTAT|DIFF_FORMAT_SHORTSTAT|DIFF_FORMAT_NUMSTAT) ||
4895             dirstat_by_line) {
4896                 struct diffstat_t diffstat;
4897
4898                 memset(&diffstat, 0, sizeof(struct diffstat_t));
4899                 for (i = 0; i < q->nr; i++) {
4900                         struct diff_filepair *p = q->queue[i];
4901                         if (check_pair_status(p))
4902                                 diff_flush_stat(p, options, &diffstat);
4903                 }
4904                 if (output_format & DIFF_FORMAT_NUMSTAT)
4905                         show_numstat(&diffstat, options);
4906                 if (output_format & DIFF_FORMAT_DIFFSTAT)
4907                         show_stats(&diffstat, options);
4908                 if (output_format & DIFF_FORMAT_SHORTSTAT)
4909                         show_shortstats(&diffstat, options);
4910                 if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
4911                         show_dirstat_by_line(&diffstat, options);
4912                 free_diffstat_info(&diffstat);
4913                 separator++;
4914         }
4915         if ((output_format & DIFF_FORMAT_DIRSTAT) && !dirstat_by_line)
4916                 show_dirstat(options);
4917
4918         if (output_format & DIFF_FORMAT_SUMMARY && !is_summary_empty(q)) {
4919                 for (i = 0; i < q->nr; i++) {
4920                         diff_summary(options, q->queue[i]);
4921                 }
4922                 separator++;
4923         }
4924
4925         if (output_format & DIFF_FORMAT_NO_OUTPUT &&
4926             DIFF_OPT_TST(options, EXIT_WITH_STATUS) &&
4927             DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4928                 /*
4929                  * run diff_flush_patch for the exit status. setting
4930                  * options->file to /dev/null should be safe, because we
4931                  * aren't supposed to produce any output anyway.
4932                  */
4933                 if (options->close_file)
4934                         fclose(options->file);
4935                 options->file = xfopen("/dev/null", "w");
4936                 options->close_file = 1;
4937                 for (i = 0; i < q->nr; i++) {
4938                         struct diff_filepair *p = q->queue[i];
4939                         if (check_pair_status(p))
4940                                 diff_flush_patch(p, options);
4941                         if (options->found_changes)
4942                                 break;
4943                 }
4944         }
4945
4946         if (output_format & DIFF_FORMAT_PATCH) {
4947                 if (separator) {
4948                         emit_diff_symbol(options, DIFF_SYMBOL_SEPARATOR, NULL, 0, 0);
4949                         if (options->stat_sep) {
4950                                 /* attach patch instead of inline */
4951                                 fputs(options->stat_sep, options->file);
4952                         }
4953                 }
4954
4955                 diff_flush_patch_all_file_pairs(options);
4956         }
4957
4958         if (output_format & DIFF_FORMAT_CALLBACK)
4959                 options->format_callback(q, options, options->format_callback_data);
4960
4961         for (i = 0; i < q->nr; i++)
4962                 diff_free_filepair(q->queue[i]);
4963 free_queue:
4964         free(q->queue);
4965         DIFF_QUEUE_CLEAR(q);
4966         if (options->close_file)
4967                 fclose(options->file);
4968
4969         /*
4970          * Report the content-level differences with HAS_CHANGES;
4971          * diff_addremove/diff_change does not set the bit when
4972          * DIFF_FROM_CONTENTS is in effect (e.g. with -w).
4973          */
4974         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS)) {
4975                 if (options->found_changes)
4976                         DIFF_OPT_SET(options, HAS_CHANGES);
4977                 else
4978                         DIFF_OPT_CLR(options, HAS_CHANGES);
4979         }
4980 }
4981
4982 static int match_filter(const struct diff_options *options, const struct diff_filepair *p)
4983 {
4984         return (((p->status == DIFF_STATUS_MODIFIED) &&
4985                  ((p->score &&
4986                    filter_bit_tst(DIFF_STATUS_FILTER_BROKEN, options)) ||
4987                   (!p->score &&
4988                    filter_bit_tst(DIFF_STATUS_MODIFIED, options)))) ||
4989                 ((p->status != DIFF_STATUS_MODIFIED) &&
4990                  filter_bit_tst(p->status, options)));
4991 }
4992
4993 static void diffcore_apply_filter(struct diff_options *options)
4994 {
4995         int i;
4996         struct diff_queue_struct *q = &diff_queued_diff;
4997         struct diff_queue_struct outq;
4998
4999         DIFF_QUEUE_CLEAR(&outq);
5000
5001         if (!options->filter)
5002                 return;
5003
5004         if (filter_bit_tst(DIFF_STATUS_FILTER_AON, options)) {
5005                 int found;
5006                 for (i = found = 0; !found && i < q->nr; i++) {
5007                         if (match_filter(options, q->queue[i]))
5008                                 found++;
5009                 }
5010                 if (found)
5011                         return;
5012
5013                 /* otherwise we will clear the whole queue
5014                  * by copying the empty outq at the end of this
5015                  * function, but first clear the current entries
5016                  * in the queue.
5017                  */
5018                 for (i = 0; i < q->nr; i++)
5019                         diff_free_filepair(q->queue[i]);
5020         }
5021         else {
5022                 /* Only the matching ones */
5023                 for (i = 0; i < q->nr; i++) {
5024                         struct diff_filepair *p = q->queue[i];
5025                         if (match_filter(options, p))
5026                                 diff_q(&outq, p);
5027                         else
5028                                 diff_free_filepair(p);
5029                 }
5030         }
5031         free(q->queue);
5032         *q = outq;
5033 }
5034
5035 /* Check whether two filespecs with the same mode and size are identical */
5036 static int diff_filespec_is_identical(struct diff_filespec *one,
5037                                       struct diff_filespec *two)
5038 {
5039         if (S_ISGITLINK(one->mode))
5040                 return 0;
5041         if (diff_populate_filespec(one, 0))
5042                 return 0;
5043         if (diff_populate_filespec(two, 0))
5044                 return 0;
5045         return !memcmp(one->data, two->data, one->size);
5046 }
5047
5048 static int diff_filespec_check_stat_unmatch(struct diff_filepair *p)
5049 {
5050         if (p->done_skip_stat_unmatch)
5051                 return p->skip_stat_unmatch_result;
5052
5053         p->done_skip_stat_unmatch = 1;
5054         p->skip_stat_unmatch_result = 0;
5055         /*
5056          * 1. Entries that come from stat info dirtiness
5057          *    always have both sides (iow, not create/delete),
5058          *    one side of the object name is unknown, with
5059          *    the same mode and size.  Keep the ones that
5060          *    do not match these criteria.  They have real
5061          *    differences.
5062          *
5063          * 2. At this point, the file is known to be modified,
5064          *    with the same mode and size, and the object
5065          *    name of one side is unknown.  Need to inspect
5066          *    the identical contents.
5067          */
5068         if (!DIFF_FILE_VALID(p->one) || /* (1) */
5069             !DIFF_FILE_VALID(p->two) ||
5070             (p->one->oid_valid && p->two->oid_valid) ||
5071             (p->one->mode != p->two->mode) ||
5072             diff_populate_filespec(p->one, CHECK_SIZE_ONLY) ||
5073             diff_populate_filespec(p->two, CHECK_SIZE_ONLY) ||
5074             (p->one->size != p->two->size) ||
5075             !diff_filespec_is_identical(p->one, p->two)) /* (2) */
5076                 p->skip_stat_unmatch_result = 1;
5077         return p->skip_stat_unmatch_result;
5078 }
5079
5080 static void diffcore_skip_stat_unmatch(struct diff_options *diffopt)
5081 {
5082         int i;
5083         struct diff_queue_struct *q = &diff_queued_diff;
5084         struct diff_queue_struct outq;
5085         DIFF_QUEUE_CLEAR(&outq);
5086
5087         for (i = 0; i < q->nr; i++) {
5088                 struct diff_filepair *p = q->queue[i];
5089
5090                 if (diff_filespec_check_stat_unmatch(p))
5091                         diff_q(&outq, p);
5092                 else {
5093                         /*
5094                          * The caller can subtract 1 from skip_stat_unmatch
5095                          * to determine how many paths were dirty only
5096                          * due to stat info mismatch.
5097                          */
5098                         if (!DIFF_OPT_TST(diffopt, NO_INDEX))
5099                                 diffopt->skip_stat_unmatch++;
5100                         diff_free_filepair(p);
5101                 }
5102         }
5103         free(q->queue);
5104         *q = outq;
5105 }
5106
5107 static int diffnamecmp(const void *a_, const void *b_)
5108 {
5109         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
5110         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
5111         const char *name_a, *name_b;
5112
5113         name_a = a->one ? a->one->path : a->two->path;
5114         name_b = b->one ? b->one->path : b->two->path;
5115         return strcmp(name_a, name_b);
5116 }
5117
5118 void diffcore_fix_diff_index(struct diff_options *options)
5119 {
5120         struct diff_queue_struct *q = &diff_queued_diff;
5121         QSORT(q->queue, q->nr, diffnamecmp);
5122 }
5123
5124 void diffcore_std(struct diff_options *options)
5125 {
5126         /* NOTE please keep the following in sync with diff_tree_combined() */
5127         if (options->skip_stat_unmatch)
5128                 diffcore_skip_stat_unmatch(options);
5129         if (!options->found_follow) {
5130                 /* See try_to_follow_renames() in tree-diff.c */
5131                 if (options->break_opt != -1)
5132                         diffcore_break(options->break_opt);
5133                 if (options->detect_rename)
5134                         diffcore_rename(options);
5135                 if (options->break_opt != -1)
5136                         diffcore_merge_broken();
5137         }
5138         if (options->pickaxe)
5139                 diffcore_pickaxe(options);
5140         if (options->orderfile)
5141                 diffcore_order(options->orderfile);
5142         if (!options->found_follow)
5143                 /* See try_to_follow_renames() in tree-diff.c */
5144                 diff_resolve_rename_copy();
5145         diffcore_apply_filter(options);
5146
5147         if (diff_queued_diff.nr && !DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5148                 DIFF_OPT_SET(options, HAS_CHANGES);
5149         else
5150                 DIFF_OPT_CLR(options, HAS_CHANGES);
5151
5152         options->found_follow = 0;
5153 }
5154
5155 int diff_result_code(struct diff_options *opt, int status)
5156 {
5157         int result = 0;
5158
5159         diff_warn_rename_limit("diff.renameLimit",
5160                                opt->needed_rename_limit,
5161                                opt->degraded_cc_to_c);
5162         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5163             !(opt->output_format & DIFF_FORMAT_CHECKDIFF))
5164                 return status;
5165         if (DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5166             DIFF_OPT_TST(opt, HAS_CHANGES))
5167                 result |= 01;
5168         if ((opt->output_format & DIFF_FORMAT_CHECKDIFF) &&
5169             DIFF_OPT_TST(opt, CHECK_FAILED))
5170                 result |= 02;
5171         return result;
5172 }
5173
5174 int diff_can_quit_early(struct diff_options *opt)
5175 {
5176         return (DIFF_OPT_TST(opt, QUICK) &&
5177                 !opt->filter &&
5178                 DIFF_OPT_TST(opt, HAS_CHANGES));
5179 }
5180
5181 /*
5182  * Shall changes to this submodule be ignored?
5183  *
5184  * Submodule changes can be configured to be ignored separately for each path,
5185  * but that configuration can be overridden from the command line.
5186  */
5187 static int is_submodule_ignored(const char *path, struct diff_options *options)
5188 {
5189         int ignored = 0;
5190         unsigned orig_flags = options->flags;
5191         if (!DIFF_OPT_TST(options, OVERRIDE_SUBMODULE_CONFIG))
5192                 set_diffopt_flags_from_submodule_config(options, path);
5193         if (DIFF_OPT_TST(options, IGNORE_SUBMODULES))
5194                 ignored = 1;
5195         options->flags = orig_flags;
5196         return ignored;
5197 }
5198
5199 void diff_addremove(struct diff_options *options,
5200                     int addremove, unsigned mode,
5201                     const struct object_id *oid,
5202                     int oid_valid,
5203                     const char *concatpath, unsigned dirty_submodule)
5204 {
5205         struct diff_filespec *one, *two;
5206
5207         if (S_ISGITLINK(mode) && is_submodule_ignored(concatpath, options))
5208                 return;
5209
5210         /* This may look odd, but it is a preparation for
5211          * feeding "there are unchanged files which should
5212          * not produce diffs, but when you are doing copy
5213          * detection you would need them, so here they are"
5214          * entries to the diff-core.  They will be prefixed
5215          * with something like '=' or '*' (I haven't decided
5216          * which but should not make any difference).
5217          * Feeding the same new and old to diff_change()
5218          * also has the same effect.
5219          * Before the final output happens, they are pruned after
5220          * merged into rename/copy pairs as appropriate.
5221          */
5222         if (DIFF_OPT_TST(options, REVERSE_DIFF))
5223                 addremove = (addremove == '+' ? '-' :
5224                              addremove == '-' ? '+' : addremove);
5225
5226         if (options->prefix &&
5227             strncmp(concatpath, options->prefix, options->prefix_length))
5228                 return;
5229
5230         one = alloc_filespec(concatpath);
5231         two = alloc_filespec(concatpath);
5232
5233         if (addremove != '+')
5234                 fill_filespec(one, oid, oid_valid, mode);
5235         if (addremove != '-') {
5236                 fill_filespec(two, oid, oid_valid, mode);
5237                 two->dirty_submodule = dirty_submodule;
5238         }
5239
5240         diff_queue(&diff_queued_diff, one, two);
5241         if (!DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5242                 DIFF_OPT_SET(options, HAS_CHANGES);
5243 }
5244
5245 void diff_change(struct diff_options *options,
5246                  unsigned old_mode, unsigned new_mode,
5247                  const struct object_id *old_oid,
5248                  const struct object_id *new_oid,
5249                  int old_oid_valid, int new_oid_valid,
5250                  const char *concatpath,
5251                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
5252 {
5253         struct diff_filespec *one, *two;
5254         struct diff_filepair *p;
5255
5256         if (S_ISGITLINK(old_mode) && S_ISGITLINK(new_mode) &&
5257             is_submodule_ignored(concatpath, options))
5258                 return;
5259
5260         if (DIFF_OPT_TST(options, REVERSE_DIFF)) {
5261                 SWAP(old_mode, new_mode);
5262                 SWAP(old_oid, new_oid);
5263                 SWAP(old_oid_valid, new_oid_valid);
5264                 SWAP(old_dirty_submodule, new_dirty_submodule);
5265         }
5266
5267         if (options->prefix &&
5268             strncmp(concatpath, options->prefix, options->prefix_length))
5269                 return;
5270
5271         one = alloc_filespec(concatpath);
5272         two = alloc_filespec(concatpath);
5273         fill_filespec(one, old_oid, old_oid_valid, old_mode);
5274         fill_filespec(two, new_oid, new_oid_valid, new_mode);
5275         one->dirty_submodule = old_dirty_submodule;
5276         two->dirty_submodule = new_dirty_submodule;
5277         p = diff_queue(&diff_queued_diff, one, two);
5278
5279         if (DIFF_OPT_TST(options, DIFF_FROM_CONTENTS))
5280                 return;
5281
5282         if (DIFF_OPT_TST(options, QUICK) && options->skip_stat_unmatch &&
5283             !diff_filespec_check_stat_unmatch(p))
5284                 return;
5285
5286         DIFF_OPT_SET(options, HAS_CHANGES);
5287 }
5288
5289 struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
5290 {
5291         struct diff_filepair *pair;
5292         struct diff_filespec *one, *two;
5293
5294         if (options->prefix &&
5295             strncmp(path, options->prefix, options->prefix_length))
5296                 return NULL;
5297
5298         one = alloc_filespec(path);
5299         two = alloc_filespec(path);
5300         pair = diff_queue(&diff_queued_diff, one, two);
5301         pair->is_unmerged = 1;
5302         return pair;
5303 }
5304
5305 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
5306                 size_t *outsize)
5307 {
5308         struct diff_tempfile *temp;
5309         const char *argv[3];
5310         const char **arg = argv;
5311         struct child_process child = CHILD_PROCESS_INIT;
5312         struct strbuf buf = STRBUF_INIT;
5313         int err = 0;
5314
5315         temp = prepare_temp_file(spec->path, spec);
5316         *arg++ = pgm;
5317         *arg++ = temp->name;
5318         *arg = NULL;
5319
5320         child.use_shell = 1;
5321         child.argv = argv;
5322         child.out = -1;
5323         if (start_command(&child)) {
5324                 remove_tempfile();
5325                 return NULL;
5326         }
5327
5328         if (strbuf_read(&buf, child.out, 0) < 0)
5329                 err = error("error reading from textconv command '%s'", pgm);
5330         close(child.out);
5331
5332         if (finish_command(&child) || err) {
5333                 strbuf_release(&buf);
5334                 remove_tempfile();
5335                 return NULL;
5336         }
5337         remove_tempfile();
5338
5339         return strbuf_detach(&buf, outsize);
5340 }
5341
5342 size_t fill_textconv(struct userdiff_driver *driver,
5343                      struct diff_filespec *df,
5344                      char **outbuf)
5345 {
5346         size_t size;
5347
5348         if (!driver) {
5349                 if (!DIFF_FILE_VALID(df)) {
5350                         *outbuf = "";
5351                         return 0;
5352                 }
5353                 if (diff_populate_filespec(df, 0))
5354                         die("unable to read files to diff");
5355                 *outbuf = df->data;
5356                 return df->size;
5357         }
5358
5359         if (!driver->textconv)
5360                 die("BUG: fill_textconv called with non-textconv driver");
5361
5362         if (driver->textconv_cache && df->oid_valid) {
5363                 *outbuf = notes_cache_get(driver->textconv_cache,
5364                                           &df->oid,
5365                                           &size);
5366                 if (*outbuf)
5367                         return size;
5368         }
5369
5370         *outbuf = run_textconv(driver->textconv, df, &size);
5371         if (!*outbuf)
5372                 die("unable to read files to diff");
5373
5374         if (driver->textconv_cache && df->oid_valid) {
5375                 /* ignore errors, as we might be in a readonly repository */
5376                 notes_cache_put(driver->textconv_cache, &df->oid, *outbuf,
5377                                 size);
5378                 /*
5379                  * we could save up changes and flush them all at the end,
5380                  * but we would need an extra call after all diffing is done.
5381                  * Since generating a cache entry is the slow path anyway,
5382                  * this extra overhead probably isn't a big deal.
5383                  */
5384                 notes_cache_write(driver->textconv_cache);
5385         }
5386
5387         return size;
5388 }
5389
5390 int textconv_object(const char *path,
5391                     unsigned mode,
5392                     const struct object_id *oid,
5393                     int oid_valid,
5394                     char **buf,
5395                     unsigned long *buf_size)
5396 {
5397         struct diff_filespec *df;
5398         struct userdiff_driver *textconv;
5399
5400         df = alloc_filespec(path);
5401         fill_filespec(df, oid, oid_valid, mode);
5402         textconv = get_textconv(df);
5403         if (!textconv) {
5404                 free_filespec(df);
5405                 return 0;
5406         }
5407
5408         *buf_size = fill_textconv(textconv, df, buf);
5409         free_filespec(df);
5410         return 1;
5411 }
5412
5413 void setup_diff_pager(struct diff_options *opt)
5414 {
5415         /*
5416          * If the user asked for our exit code, then either they want --quiet
5417          * or --exit-code. We should definitely not bother with a pager in the
5418          * former case, as we will generate no output. Since we still properly
5419          * report our exit code even when a pager is run, we _could_ run a
5420          * pager with --exit-code. But since we have not done so historically,
5421          * and because it is easy to find people oneline advising "git diff
5422          * --exit-code" in hooks and other scripts, we do not do so.
5423          */
5424         if (!DIFF_OPT_TST(opt, EXIT_WITH_STATUS) &&
5425             check_pager_config("diff") != 0)
5426                 setup_pager();
5427 }