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