builtin/am.c

   1 /*
   2  * Builtin "git am"
   3  *
   4  * Based on git-am.sh by Junio C Hamano.
   5  */
   6 #include "cache.h"
   7 #include "config.h"
   8 #include "builtin.h"
   9 #include "exec_cmd.h"
  10 #include "parse-options.h"
  11 #include "dir.h"
  12 #include "run-command.h"
  13 #include "quote.h"
  14 #include "tempfile.h"
  15 #include "lockfile.h"
  16 #include "cache-tree.h"
  17 #include "refs.h"
  18 #include "commit.h"
  19 #include "diff.h"
  20 #include "diffcore.h"
  21 #include "unpack-trees.h"
  22 #include "branch.h"
  23 #include "sequencer.h"
  24 #include "revision.h"
  25 #include "merge-recursive.h"
  26 #include "revision.h"
  27 #include "log-tree.h"
  28 #include "notes-utils.h"
  29 #include "rerere.h"
  30 #include "prompt.h"
  31 #include "mailinfo.h"
  32 #include "apply.h"
  33 #include "string-list.h"
  34
  35 /**
  36  * Returns 1 if the file is empty or does not exist, 0 otherwise.
  37  */
  38 static int is_empty_file(const char *filename)
  39 {
  40         struct stat st;
  41
  42         if (stat(filename, &st) < 0) {
  43                 if (errno == ENOENT)
  44                         return 1;
  45                 die_errno(_("could not stat %s"), filename);
  46         }
  47
  48         return !st.st_size;
  49 }
  50
  51 /**
  52  * Returns the length of the first line of msg.
  53  */
  54 static int linelen(const char *msg)
  55 {
  56         return strchrnul(msg, '\n') - msg;
  57 }
  58
  59 /**
  60  * Returns true if `str` consists of only whitespace, false otherwise.
  61  */
  62 static int str_isspace(const char *str)
  63 {
  64         for (; *str; str++)
  65                 if (!isspace(*str))
  66                         return 0;
  67
  68         return 1;
  69 }
  70
  71 enum patch_format {
  72         PATCH_FORMAT_UNKNOWN = 0,
  73         PATCH_FORMAT_MBOX,
  74         PATCH_FORMAT_STGIT,
  75         PATCH_FORMAT_STGIT_SERIES,
  76         PATCH_FORMAT_HG,
  77         PATCH_FORMAT_MBOXRD
  78 };
  79
  80 enum keep_type {
  81         KEEP_FALSE = 0,
  82         KEEP_TRUE,      /* pass -k flag to git-mailinfo */
  83         KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
  84 };
  85
  86 enum scissors_type {
  87         SCISSORS_UNSET = -1,
  88         SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
  89         SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
  90 };
  91
  92 enum signoff_type {
  93         SIGNOFF_FALSE = 0,
  94         SIGNOFF_TRUE = 1,
  95         SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
  96 };
  97
  98 struct am_state {
  99         /* state directory path */
 100         char *dir;
 101
 102         /* current and last patch numbers, 1-indexed */
 103         int cur;
 104         int last;
 105
 106         /* commit metadata and message */
 107         char *author_name;
 108         char *author_email;
 109         char *author_date;
 110         char *msg;
 111         size_t msg_len;
 112
 113         /* when --rebasing, records the original commit the patch came from */
 114         struct object_id orig_commit;
 115
 116         /* number of digits in patch filename */
 117         int prec;
 118
 119         /* various operating modes and command line options */
 120         int interactive;
 121         int threeway;
 122         int quiet;
 123         int signoff; /* enum signoff_type */
 124         int utf8;
 125         int keep; /* enum keep_type */
 126         int message_id;
 127         int scissors; /* enum scissors_type */
 128         struct argv_array git_apply_opts;
 129         const char *resolvemsg;
 130         int committer_date_is_author_date;
 131         int ignore_date;
 132         int allow_rerere_autoupdate;
 133         const char *sign_commit;
 134         int rebasing;
 135 };
 136
 137 /**
 138  * Initializes am_state with the default values.
 139  */
 140 static void am_state_init(struct am_state *state)
 141 {
 142         int gpgsign;
 143
 144         memset(state, 0, sizeof(*state));
 145
 146         state->dir = git_pathdup("rebase-apply");
 147
 148         state->prec = 4;
 149
 150         git_config_get_bool("am.threeway", &state->threeway);
 151
 152         state->utf8 = 1;
 153
 154         git_config_get_bool("am.messageid", &state->message_id);
 155
 156         state->scissors = SCISSORS_UNSET;
 157
 158         argv_array_init(&state->git_apply_opts);
 159
 160         if (!git_config_get_bool("commit.gpgsign", &gpgsign))
 161                 state->sign_commit = gpgsign ? "" : NULL;
 162 }
 163
 164 /**
 165  * Releases memory allocated by an am_state.
 166  */
 167 static void am_state_release(struct am_state *state)
 168 {
 169         free(state->dir);
 170         free(state->author_name);
 171         free(state->author_email);
 172         free(state->author_date);
 173         free(state->msg);
 174         argv_array_clear(&state->git_apply_opts);
 175 }
 176
 177 /**
 178  * Returns path relative to the am_state directory.
 179  */
 180 static inline const char *am_path(const struct am_state *state, const char *path)
 181 {
 182         return mkpath("%s/%s", state->dir, path);
 183 }
 184
 185 /**
 186  * For convenience to call write_file()
 187  */
 188 static void write_state_text(const struct am_state *state,
 189                              const char *name, const char *string)
 190 {
 191         write_file(am_path(state, name), "%s", string);
 192 }
 193
 194 static void write_state_count(const struct am_state *state,
 195                               const char *name, int value)
 196 {
 197         write_file(am_path(state, name), "%d", value);
 198 }
 199
 200 static void write_state_bool(const struct am_state *state,
 201                              const char *name, int value)
 202 {
 203         write_state_text(state, name, value ? "t" : "f");
 204 }
 205
 206 /**
 207  * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
 208  * at the end.
 209  */
 210 static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
 211 {
 212         va_list ap;
 213
 214         va_start(ap, fmt);
 215         if (!state->quiet) {
 216                 vfprintf(fp, fmt, ap);
 217                 putc('\n', fp);
 218         }
 219         va_end(ap);
 220 }
 221
 222 /**
 223  * Returns 1 if there is an am session in progress, 0 otherwise.
 224  */
 225 static int am_in_progress(const struct am_state *state)
 226 {
 227         struct stat st;
 228
 229         if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
 230                 return 0;
 231         if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
 232                 return 0;
 233         if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
 234                 return 0;
 235         return 1;
 236 }
 237
 238 /**
 239  * Reads the contents of `file` in the `state` directory into `sb`. Returns the
 240  * number of bytes read on success, -1 if the file does not exist. If `trim` is
 241  * set, trailing whitespace will be removed.
 242  */
 243 static int read_state_file(struct strbuf *sb, const struct am_state *state,
 244                         const char *file, int trim)
 245 {
 246         strbuf_reset(sb);
 247
 248         if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
 249                 if (trim)
 250                         strbuf_trim(sb);
 251
 252                 return sb->len;
 253         }
 254
 255         if (errno == ENOENT)
 256                 return -1;
 257
 258         die_errno(_("could not read '%s'"), am_path(state, file));
 259 }
 260
 261 /**
 262  * Take a series of KEY='VALUE' lines where VALUE part is
 263  * sq-quoted, and append <KEY, VALUE> at the end of the string list
 264  */
 265 static int parse_key_value_squoted(char *buf, struct string_list *list)
 266 {
 267         while (*buf) {
 268                 struct string_list_item *item;
 269                 char *np;
 270                 char *cp = strchr(buf, '=');
 271                 if (!cp)
 272                         return -1;
 273                 np = strchrnul(cp, '\n');
 274                 *cp++ = '\0';
 275                 item = string_list_append(list, buf);
 276
 277                 buf = np + (*np == '\n');
 278                 *np = '\0';
 279                 cp = sq_dequote(cp);
 280                 if (!cp)
 281                         return -1;
 282                 item->util = xstrdup(cp);
 283         }
 284         return 0;
 285 }
 286
 287 /**
 288  * Reads and parses the state directory's "author-script" file, and sets
 289  * state->author_name, state->author_email and state->author_date accordingly.
 290  * Returns 0 on success, -1 if the file could not be parsed.
 291  *
 292  * The author script is of the format:
 293  *
 294  *      GIT_AUTHOR_NAME='$author_name'
 295  *      GIT_AUTHOR_EMAIL='$author_email'
 296  *      GIT_AUTHOR_DATE='$author_date'
 297  *
 298  * where $author_name, $author_email and $author_date are quoted. We are strict
 299  * with our parsing, as the file was meant to be eval'd in the old git-am.sh
 300  * script, and thus if the file differs from what this function expects, it is
 301  * better to bail out than to do something that the user does not expect.
 302  */
 303 static int read_author_script(struct am_state *state)
 304 {
 305         const char *filename = am_path(state, "author-script");
 306         struct strbuf buf = STRBUF_INIT;
 307         struct string_list kv = STRING_LIST_INIT_DUP;
 308         int retval = -1; /* assume failure */
 309         int fd;
 310
 311         assert(!state->author_name);
 312         assert(!state->author_email);
 313         assert(!state->author_date);
 314
 315         fd = open(filename, O_RDONLY);
 316         if (fd < 0) {
 317                 if (errno == ENOENT)
 318                         return 0;
 319                 die_errno(_("could not open '%s' for reading"), filename);
 320         }
 321         strbuf_read(&buf, fd, 0);
 322         close(fd);
 323         if (parse_key_value_squoted(buf.buf, &kv))
 324                 goto finish;
 325
 326         if (kv.nr != 3 ||
 327             strcmp(kv.items[0].string, "GIT_AUTHOR_NAME") ||
 328             strcmp(kv.items[1].string, "GIT_AUTHOR_EMAIL") ||
 329             strcmp(kv.items[2].string, "GIT_AUTHOR_DATE"))
 330                 goto finish;
 331         state->author_name = kv.items[0].util;
 332         state->author_email = kv.items[1].util;
 333         state->author_date = kv.items[2].util;
 334         retval = 0;
 335 finish:
 336         string_list_clear(&kv, !!retval);
 337         strbuf_release(&buf);
 338         return retval;
 339 }
 340
 341 /**
 342  * Saves state->author_name, state->author_email and state->author_date in the
 343  * state directory's "author-script" file.
 344  */
 345 static void write_author_script(const struct am_state *state)
 346 {
 347         struct strbuf sb = STRBUF_INIT;
 348
 349         strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
 350         sq_quote_buf(&sb, state->author_name);
 351         strbuf_addch(&sb, '\n');
 352
 353         strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
 354         sq_quote_buf(&sb, state->author_email);
 355         strbuf_addch(&sb, '\n');
 356
 357         strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
 358         sq_quote_buf(&sb, state->author_date);
 359         strbuf_addch(&sb, '\n');
 360
 361         write_state_text(state, "author-script", sb.buf);
 362
 363         strbuf_release(&sb);
 364 }
 365
 366 /**
 367  * Reads the commit message from the state directory's "final-commit" file,
 368  * setting state->msg to its contents and state->msg_len to the length of its
 369  * contents in bytes.
 370  *
 371  * Returns 0 on success, -1 if the file does not exist.
 372  */
 373 static int read_commit_msg(struct am_state *state)
 374 {
 375         struct strbuf sb = STRBUF_INIT;
 376
 377         assert(!state->msg);
 378
 379         if (read_state_file(&sb, state, "final-commit", 0) < 0) {
 380                 strbuf_release(&sb);
 381                 return -1;
 382         }
 383
 384         state->msg = strbuf_detach(&sb, &state->msg_len);
 385         return 0;
 386 }
 387
 388 /**
 389  * Saves state->msg in the state directory's "final-commit" file.
 390  */
 391 static void write_commit_msg(const struct am_state *state)
 392 {
 393         const char *filename = am_path(state, "final-commit");
 394         write_file_buf(filename, state->msg, state->msg_len);
 395 }
 396
 397 /**
 398  * Loads state from disk.
 399  */
 400 static void am_load(struct am_state *state)
 401 {
 402         struct strbuf sb = STRBUF_INIT;
 403
 404         if (read_state_file(&sb, state, "next", 1) < 0)
 405                 die("BUG: state file 'next' does not exist");
 406         state->cur = strtol(sb.buf, NULL, 10);
 407
 408         if (read_state_file(&sb, state, "last", 1) < 0)
 409                 die("BUG: state file 'last' does not exist");
 410         state->last = strtol(sb.buf, NULL, 10);
 411
 412         if (read_author_script(state) < 0)
 413                 die(_("could not parse author script"));
 414
 415         read_commit_msg(state);
 416
 417         if (read_state_file(&sb, state, "original-commit", 1) < 0)
 418                 oidclr(&state->orig_commit);
 419         else if (get_oid_hex(sb.buf, &state->orig_commit) < 0)
 420                 die(_("could not parse %s"), am_path(state, "original-commit"));
 421
 422         read_state_file(&sb, state, "threeway", 1);
 423         state->threeway = !strcmp(sb.buf, "t");
 424
 425         read_state_file(&sb, state, "quiet", 1);
 426         state->quiet = !strcmp(sb.buf, "t");
 427
 428         read_state_file(&sb, state, "sign", 1);
 429         state->signoff = !strcmp(sb.buf, "t");
 430
 431         read_state_file(&sb, state, "utf8", 1);
 432         state->utf8 = !strcmp(sb.buf, "t");
 433
 434         if (file_exists(am_path(state, "rerere-autoupdate"))) {
 435                 read_state_file(&sb, state, "rerere-autoupdate", 1);
 436                 state->allow_rerere_autoupdate = strcmp(sb.buf, "t") ?
 437                         RERERE_NOAUTOUPDATE : RERERE_AUTOUPDATE;
 438         } else {
 439                 state->allow_rerere_autoupdate = 0;
 440         }
 441
 442         read_state_file(&sb, state, "keep", 1);
 443         if (!strcmp(sb.buf, "t"))
 444                 state->keep = KEEP_TRUE;
 445         else if (!strcmp(sb.buf, "b"))
 446                 state->keep = KEEP_NON_PATCH;
 447         else
 448                 state->keep = KEEP_FALSE;
 449
 450         read_state_file(&sb, state, "messageid", 1);
 451         state->message_id = !strcmp(sb.buf, "t");
 452
 453         read_state_file(&sb, state, "scissors", 1);
 454         if (!strcmp(sb.buf, "t"))
 455                 state->scissors = SCISSORS_TRUE;
 456         else if (!strcmp(sb.buf, "f"))
 457                 state->scissors = SCISSORS_FALSE;
 458         else
 459                 state->scissors = SCISSORS_UNSET;
 460
 461         read_state_file(&sb, state, "apply-opt", 1);
 462         argv_array_clear(&state->git_apply_opts);
 463         if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
 464                 die(_("could not parse %s"), am_path(state, "apply-opt"));
 465
 466         state->rebasing = !!file_exists(am_path(state, "rebasing"));
 467
 468         strbuf_release(&sb);
 469 }
 470
 471 /**
 472  * Removes the am_state directory, forcefully terminating the current am
 473  * session.
 474  */
 475 static void am_destroy(const struct am_state *state)
 476 {
 477         struct strbuf sb = STRBUF_INIT;
 478
 479         strbuf_addstr(&sb, state->dir);
 480         remove_dir_recursively(&sb, 0);
 481         strbuf_release(&sb);
 482 }
 483
 484 /**
 485  * Runs applypatch-msg hook. Returns its exit code.
 486  */
 487 static int run_applypatch_msg_hook(struct am_state *state)
 488 {
 489         int ret;
 490
 491         assert(state->msg);
 492         ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
 493
 494         if (!ret) {
 495                 FREE_AND_NULL(state->msg);
 496                 if (read_commit_msg(state) < 0)
 497                         die(_("'%s' was deleted by the applypatch-msg hook"),
 498                                 am_path(state, "final-commit"));
 499         }
 500
 501         return ret;
 502 }
 503
 504 /**
 505  * Runs post-rewrite hook. Returns it exit code.
 506  */
 507 static int run_post_rewrite_hook(const struct am_state *state)
 508 {
 509         struct child_process cp = CHILD_PROCESS_INIT;
 510         const char *hook = find_hook("post-rewrite");
 511         int ret;
 512
 513         if (!hook)
 514                 return 0;
 515
 516         argv_array_push(&cp.args, hook);
 517         argv_array_push(&cp.args, "rebase");
 518
 519         cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
 520         cp.stdout_to_stderr = 1;
 521
 522         ret = run_command(&cp);
 523
 524         close(cp.in);
 525         return ret;
 526 }
 527
 528 /**
 529  * Reads the state directory's "rewritten" file, and copies notes from the old
 530  * commits listed in the file to their rewritten commits.
 531  *
 532  * Returns 0 on success, -1 on failure.
 533  */
 534 static int copy_notes_for_rebase(const struct am_state *state)
 535 {
 536         struct notes_rewrite_cfg *c;
 537         struct strbuf sb = STRBUF_INIT;
 538         const char *invalid_line = _("Malformed input line: '%s'.");
 539         const char *msg = "Notes added by 'git rebase'";
 540         FILE *fp;
 541         int ret = 0;
 542
 543         assert(state->rebasing);
 544
 545         c = init_copy_notes_for_rewrite("rebase");
 546         if (!c)
 547                 return 0;
 548
 549         fp = xfopen(am_path(state, "rewritten"), "r");
 550
 551         while (!strbuf_getline_lf(&sb, fp)) {
 552                 struct object_id from_obj, to_obj;
 553
 554                 if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
 555                         ret = error(invalid_line, sb.buf);
 556                         goto finish;
 557                 }
 558
 559                 if (get_oid_hex(sb.buf, &from_obj)) {
 560                         ret = error(invalid_line, sb.buf);
 561                         goto finish;
 562                 }
 563
 564                 if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
 565                         ret = error(invalid_line, sb.buf);
 566                         goto finish;
 567                 }
 568
 569                 if (get_oid_hex(sb.buf + GIT_SHA1_HEXSZ + 1, &to_obj)) {
 570                         ret = error(invalid_line, sb.buf);
 571                         goto finish;
 572                 }
 573
 574                 if (copy_note_for_rewrite(c, &from_obj, &to_obj))
 575                         ret = error(_("Failed to copy notes from '%s' to '%s'"),
 576                                         oid_to_hex(&from_obj), oid_to_hex(&to_obj));
 577         }
 578
 579 finish:
 580         finish_copy_notes_for_rewrite(c, msg);
 581         fclose(fp);
 582         strbuf_release(&sb);
 583         return ret;
 584 }
 585
 586 /**
 587  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
 588  * non-indented lines and checking if they look like they begin with valid
 589  * header field names.
 590  *
 591  * Returns 1 if the file looks like a piece of mail, 0 otherwise.
 592  */
 593 static int is_mail(FILE *fp)
 594 {
 595         const char *header_regex = "^[!-9;-~]+:";
 596         struct strbuf sb = STRBUF_INIT;
 597         regex_t regex;
 598         int ret = 1;
 599
 600         if (fseek(fp, 0L, SEEK_SET))
 601                 die_errno(_("fseek failed"));
 602
 603         if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
 604                 die("invalid pattern: %s", header_regex);
 605
 606         while (!strbuf_getline(&sb, fp)) {
 607                 if (!sb.len)
 608                         break; /* End of header */
 609
 610                 /* Ignore indented folded lines */
 611                 if (*sb.buf == '\t' || *sb.buf == ' ')
 612                         continue;
 613
 614                 /* It's a header if it matches header_regex */
 615                 if (regexec(&regex, sb.buf, 0, NULL, 0)) {
 616                         ret = 0;
 617                         goto done;
 618                 }
 619         }
 620
 621 done:
 622         regfree(&regex);
 623         strbuf_release(&sb);
 624         return ret;
 625 }
 626
 627 /**
 628  * Attempts to detect the patch_format of the patches contained in `paths`,
 629  * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
 630  * detection fails.
 631  */
 632 static int detect_patch_format(const char **paths)
 633 {
 634         enum patch_format ret = PATCH_FORMAT_UNKNOWN;
 635         struct strbuf l1 = STRBUF_INIT;
 636         struct strbuf l2 = STRBUF_INIT;
 637         struct strbuf l3 = STRBUF_INIT;
 638         FILE *fp;
 639
 640         /*
 641          * We default to mbox format if input is from stdin and for directories
 642          */
 643         if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
 644                 return PATCH_FORMAT_MBOX;
 645
 646         /*
 647          * Otherwise, check the first few lines of the first patch, starting
 648          * from the first non-blank line, to try to detect its format.
 649          */
 650
 651         fp = xfopen(*paths, "r");
 652
 653         while (!strbuf_getline(&l1, fp)) {
 654                 if (l1.len)
 655                         break;
 656         }
 657
 658         if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
 659                 ret = PATCH_FORMAT_MBOX;
 660                 goto done;
 661         }
 662
 663         if (starts_with(l1.buf, "# This series applies on GIT commit")) {
 664                 ret = PATCH_FORMAT_STGIT_SERIES;
 665                 goto done;
 666         }
 667
 668         if (!strcmp(l1.buf, "# HG changeset patch")) {
 669                 ret = PATCH_FORMAT_HG;
 670                 goto done;
 671         }
 672
 673         strbuf_reset(&l2);
 674         strbuf_getline(&l2, fp);
 675         strbuf_reset(&l3);
 676         strbuf_getline(&l3, fp);
 677
 678         /*
 679          * If the second line is empty and the third is a From, Author or Date
 680          * entry, this is likely an StGit patch.
 681          */
 682         if (l1.len && !l2.len &&
 683                 (starts_with(l3.buf, "From:") ||
 684                  starts_with(l3.buf, "Author:") ||
 685                  starts_with(l3.buf, "Date:"))) {
 686                 ret = PATCH_FORMAT_STGIT;
 687                 goto done;
 688         }
 689
 690         if (l1.len && is_mail(fp)) {
 691                 ret = PATCH_FORMAT_MBOX;
 692                 goto done;
 693         }
 694
 695 done:
 696         fclose(fp);
 697         strbuf_release(&l1);
 698         return ret;
 699 }
 700
 701 /**
 702  * Splits out individual email patches from `paths`, where each path is either
 703  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
 704  */
 705 static int split_mail_mbox(struct am_state *state, const char **paths,
 706                                 int keep_cr, int mboxrd)
 707 {
 708         struct child_process cp = CHILD_PROCESS_INIT;
 709         struct strbuf last = STRBUF_INIT;
 710
 711         cp.git_cmd = 1;
 712         argv_array_push(&cp.args, "mailsplit");
 713         argv_array_pushf(&cp.args, "-d%d", state->prec);
 714         argv_array_pushf(&cp.args, "-o%s", state->dir);
 715         argv_array_push(&cp.args, "-b");
 716         if (keep_cr)
 717                 argv_array_push(&cp.args, "--keep-cr");
 718         if (mboxrd)
 719                 argv_array_push(&cp.args, "--mboxrd");
 720         argv_array_push(&cp.args, "--");
 721         argv_array_pushv(&cp.args, paths);
 722
 723         if (capture_command(&cp, &last, 8))
 724                 return -1;
 725
 726         state->cur = 1;
 727         state->last = strtol(last.buf, NULL, 10);
 728
 729         return 0;
 730 }
 731
 732 /**
 733  * Callback signature for split_mail_conv(). The foreign patch should be
 734  * read from `in`, and the converted patch (in RFC2822 mail format) should be
 735  * written to `out`. Return 0 on success, or -1 on failure.
 736  */
 737 typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
 738
 739 /**
 740  * Calls `fn` for each file in `paths` to convert the foreign patch to the
 741  * RFC2822 mail format suitable for parsing with git-mailinfo.
 742  *
 743  * Returns 0 on success, -1 on failure.
 744  */
 745 static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
 746                         const char **paths, int keep_cr)
 747 {
 748         static const char *stdin_only[] = {"-", NULL};
 749         int i;
 750
 751         if (!*paths)
 752                 paths = stdin_only;
 753
 754         for (i = 0; *paths; paths++, i++) {
 755                 FILE *in, *out;
 756                 const char *mail;
 757                 int ret;
 758
 759                 if (!strcmp(*paths, "-"))
 760                         in = stdin;
 761                 else
 762                         in = fopen(*paths, "r");
 763
 764                 if (!in)
 765                         return error_errno(_("could not open '%s' for reading"),
 766                                            *paths);
 767
 768                 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 769
 770                 out = fopen(mail, "w");
 771                 if (!out) {
 772                         if (in != stdin)
 773                                 fclose(in);
 774                         return error_errno(_("could not open '%s' for writing"),
 775                                            mail);
 776                 }
 777
 778                 ret = fn(out, in, keep_cr);
 779
 780                 fclose(out);
 781                 if (in != stdin)
 782                         fclose(in);
 783
 784                 if (ret)
 785                         return error(_("could not parse patch '%s'"), *paths);
 786         }
 787
 788         state->cur = 1;
 789         state->last = i;
 790         return 0;
 791 }
 792
 793 /**
 794  * A split_mail_conv() callback that converts an StGit patch to an RFC2822
 795  * message suitable for parsing with git-mailinfo.
 796  */
 797 static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 798 {
 799         struct strbuf sb = STRBUF_INIT;
 800         int subject_printed = 0;
 801
 802         while (!strbuf_getline_lf(&sb, in)) {
 803                 const char *str;
 804
 805                 if (str_isspace(sb.buf))
 806                         continue;
 807                 else if (skip_prefix(sb.buf, "Author:", &str))
 808                         fprintf(out, "From:%s\n", str);
 809                 else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
 810                         fprintf(out, "%s\n", sb.buf);
 811                 else if (!subject_printed) {
 812                         fprintf(out, "Subject: %s\n", sb.buf);
 813                         subject_printed = 1;
 814                 } else {
 815                         fprintf(out, "\n%s\n", sb.buf);
 816                         break;
 817                 }
 818         }
 819
 820         strbuf_reset(&sb);
 821         while (strbuf_fread(&sb, 8192, in) > 0) {
 822                 fwrite(sb.buf, 1, sb.len, out);
 823                 strbuf_reset(&sb);
 824         }
 825
 826         strbuf_release(&sb);
 827         return 0;
 828 }
 829
 830 /**
 831  * This function only supports a single StGit series file in `paths`.
 832  *
 833  * Given an StGit series file, converts the StGit patches in the series into
 834  * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
 835  * the state directory.
 836  *
 837  * Returns 0 on success, -1 on failure.
 838  */
 839 static int split_mail_stgit_series(struct am_state *state, const char **paths,
 840                                         int keep_cr)
 841 {
 842         const char *series_dir;
 843         char *series_dir_buf;
 844         FILE *fp;
 845         struct argv_array patches = ARGV_ARRAY_INIT;
 846         struct strbuf sb = STRBUF_INIT;
 847         int ret;
 848
 849         if (!paths[0] || paths[1])
 850                 return error(_("Only one StGIT patch series can be applied at once"));
 851
 852         series_dir_buf = xstrdup(*paths);
 853         series_dir = dirname(series_dir_buf);
 854
 855         fp = fopen(*paths, "r");
 856         if (!fp)
 857                 return error_errno(_("could not open '%s' for reading"), *paths);
 858
 859         while (!strbuf_getline_lf(&sb, fp)) {
 860                 if (*sb.buf == '#')
 861                         continue; /* skip comment lines */
 862
 863                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
 864         }
 865
 866         fclose(fp);
 867         strbuf_release(&sb);
 868         free(series_dir_buf);
 869
 870         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
 871
 872         argv_array_clear(&patches);
 873         return ret;
 874 }
 875
 876 /**
 877  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
 878  * message suitable for parsing with git-mailinfo.
 879  */
 880 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 881 {
 882         struct strbuf sb = STRBUF_INIT;
 883
 884         while (!strbuf_getline_lf(&sb, in)) {
 885                 const char *str;
 886
 887                 if (skip_prefix(sb.buf, "# User ", &str))
 888                         fprintf(out, "From: %s\n", str);
 889                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
 890                         timestamp_t timestamp;
 891                         long tz, tz2;
 892                         char *end;
 893
 894                         errno = 0;
 895                         timestamp = parse_timestamp(str, &end, 10);
 896                         if (errno)
 897                                 return error(_("invalid timestamp"));
 898
 899                         if (!skip_prefix(end, " ", &str))
 900                                 return error(_("invalid Date line"));
 901
 902                         errno = 0;
 903                         tz = strtol(str, &end, 10);
 904                         if (errno)
 905                                 return error(_("invalid timezone offset"));
 906
 907                         if (*end)
 908                                 return error(_("invalid Date line"));
 909
 910                         /*
 911                          * mercurial's timezone is in seconds west of UTC,
 912                          * however git's timezone is in hours + minutes east of
 913                          * UTC. Convert it.
 914                          */
 915                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
 916                         if (tz > 0)
 917                                 tz2 = -tz2;
 918
 919                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
 920                 } else if (starts_with(sb.buf, "# ")) {
 921                         continue;
 922                 } else {
 923                         fprintf(out, "\n%s\n", sb.buf);
 924                         break;
 925                 }
 926         }
 927
 928         strbuf_reset(&sb);
 929         while (strbuf_fread(&sb, 8192, in) > 0) {
 930                 fwrite(sb.buf, 1, sb.len, out);
 931                 strbuf_reset(&sb);
 932         }
 933
 934         strbuf_release(&sb);
 935         return 0;
 936 }
 937
 938 /**
 939  * Splits a list of files/directories into individual email patches. Each path
 940  * in `paths` must be a file/directory that is formatted according to
 941  * `patch_format`.
 942  *
 943  * Once split out, the individual email patches will be stored in the state
 944  * directory, with each patch's filename being its index, padded to state->prec
 945  * digits.
 946  *
 947  * state->cur will be set to the index of the first mail, and state->last will
 948  * be set to the index of the last mail.
 949  *
 950  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
 951  * to disable this behavior, -1 to use the default configured setting.
 952  *
 953  * Returns 0 on success, -1 on failure.
 954  */
 955 static int split_mail(struct am_state *state, enum patch_format patch_format,
 956                         const char **paths, int keep_cr)
 957 {
 958         if (keep_cr < 0) {
 959                 keep_cr = 0;
 960                 git_config_get_bool("am.keepcr", &keep_cr);
 961         }
 962
 963         switch (patch_format) {
 964         case PATCH_FORMAT_MBOX:
 965                 return split_mail_mbox(state, paths, keep_cr, 0);
 966         case PATCH_FORMAT_STGIT:
 967                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 968         case PATCH_FORMAT_STGIT_SERIES:
 969                 return split_mail_stgit_series(state, paths, keep_cr);
 970         case PATCH_FORMAT_HG:
 971                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
 972         case PATCH_FORMAT_MBOXRD:
 973                 return split_mail_mbox(state, paths, keep_cr, 1);
 974         default:
 975                 die("BUG: invalid patch_format");
 976         }
 977         return -1;
 978 }
 979
 980 /**
 981  * Setup a new am session for applying patches
 982  */
 983 static void am_setup(struct am_state *state, enum patch_format patch_format,
 984                         const char **paths, int keep_cr)
 985 {
 986         struct object_id curr_head;
 987         const char *str;
 988         struct strbuf sb = STRBUF_INIT;
 989
 990         if (!patch_format)
 991                 patch_format = detect_patch_format(paths);
 992
 993         if (!patch_format) {
 994                 fprintf_ln(stderr, _("Patch format detection failed."));
 995                 exit(128);
 996         }
 997
 998         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 999                 die_errno(_("failed to create directory '%s'"), state->dir);
1000
1001         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
1002                 am_destroy(state);
1003                 die(_("Failed to split patches."));
1004         }
1005
1006         if (state->rebasing)
1007                 state->threeway = 1;
1008
1009         write_state_bool(state, "threeway", state->threeway);
1010         write_state_bool(state, "quiet", state->quiet);
1011         write_state_bool(state, "sign", state->signoff);
1012         write_state_bool(state, "utf8", state->utf8);
1013
1014         if (state->allow_rerere_autoupdate)
1015                 write_state_bool(state, "rerere-autoupdate",
1016                          state->allow_rerere_autoupdate == RERERE_AUTOUPDATE);
1017
1018         switch (state->keep) {
1019         case KEEP_FALSE:
1020                 str = "f";
1021                 break;
1022         case KEEP_TRUE:
1023                 str = "t";
1024                 break;
1025         case KEEP_NON_PATCH:
1026                 str = "b";
1027                 break;
1028         default:
1029                 die("BUG: invalid value for state->keep");
1030         }
1031
1032         write_state_text(state, "keep", str);
1033         write_state_bool(state, "messageid", state->message_id);
1034
1035         switch (state->scissors) {
1036         case SCISSORS_UNSET:
1037                 str = "";
1038                 break;
1039         case SCISSORS_FALSE:
1040                 str = "f";
1041                 break;
1042         case SCISSORS_TRUE:
1043                 str = "t";
1044                 break;
1045         default:
1046                 die("BUG: invalid value for state->scissors");
1047         }
1048         write_state_text(state, "scissors", str);
1049
1050         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1051         write_state_text(state, "apply-opt", sb.buf);
1052
1053         if (state->rebasing)
1054                 write_state_text(state, "rebasing", "");
1055         else
1056                 write_state_text(state, "applying", "");
1057
1058         if (!get_oid("HEAD", &curr_head)) {
1059                 write_state_text(state, "abort-safety", oid_to_hex(&curr_head));
1060                 if (!state->rebasing)
1061                         update_ref_oid("am", "ORIG_HEAD", &curr_head, NULL, 0,
1062                                         UPDATE_REFS_DIE_ON_ERR);
1063         } else {
1064                 write_state_text(state, "abort-safety", "");
1065                 if (!state->rebasing)
1066                         delete_ref(NULL, "ORIG_HEAD", NULL, 0);
1067         }
1068
1069         /*
1070          * NOTE: Since the "next" and "last" files determine if an am_state
1071          * session is in progress, they should be written last.
1072          */
1073
1074         write_state_count(state, "next", state->cur);
1075         write_state_count(state, "last", state->last);
1076
1077         strbuf_release(&sb);
1078 }
1079
1080 /**
1081  * Increments the patch pointer, and cleans am_state for the application of the
1082  * next patch.
1083  */
1084 static void am_next(struct am_state *state)
1085 {
1086         struct object_id head;
1087
1088         FREE_AND_NULL(state->author_name);
1089         FREE_AND_NULL(state->author_email);
1090         FREE_AND_NULL(state->author_date);
1091         FREE_AND_NULL(state->msg);
1092         state->msg_len = 0;
1093
1094         unlink(am_path(state, "author-script"));
1095         unlink(am_path(state, "final-commit"));
1096
1097         oidclr(&state->orig_commit);
1098         unlink(am_path(state, "original-commit"));
1099
1100         if (!get_oid("HEAD", &head))
1101                 write_state_text(state, "abort-safety", oid_to_hex(&head));
1102         else
1103                 write_state_text(state, "abort-safety", "");
1104
1105         state->cur++;
1106         write_state_count(state, "next", state->cur);
1107 }
1108
1109 /**
1110  * Returns the filename of the current patch email.
1111  */
1112 static const char *msgnum(const struct am_state *state)
1113 {
1114         static struct strbuf sb = STRBUF_INIT;
1115
1116         strbuf_reset(&sb);
1117         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1118
1119         return sb.buf;
1120 }
1121
1122 /**
1123  * Refresh and write index.
1124  */
1125 static void refresh_and_write_cache(void)
1126 {
1127         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1128
1129         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1130         refresh_cache(REFRESH_QUIET);
1131         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1132                 die(_("unable to write index file"));
1133 }
1134
1135 /**
1136  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1137  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1138  * strbuf is provided, the space-separated list of files that differ will be
1139  * appended to it.
1140  */
1141 static int index_has_changes(struct strbuf *sb)
1142 {
1143         struct object_id head;
1144         int i;
1145
1146         if (!get_sha1_tree("HEAD", head.hash)) {
1147                 struct diff_options opt;
1148
1149                 diff_setup(&opt);
1150                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1151                 if (!sb)
1152                         DIFF_OPT_SET(&opt, QUICK);
1153                 do_diff_cache(&head, &opt);
1154                 diffcore_std(&opt);
1155                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1156                         if (i)
1157                                 strbuf_addch(sb, ' ');
1158                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1159                 }
1160                 diff_flush(&opt);
1161                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1162         } else {
1163                 for (i = 0; sb && i < active_nr; i++) {
1164                         if (i)
1165                                 strbuf_addch(sb, ' ');
1166                         strbuf_addstr(sb, active_cache[i]->name);
1167                 }
1168                 return !!active_nr;
1169         }
1170 }
1171
1172 /**
1173  * Dies with a user-friendly message on how to proceed after resolving the
1174  * problem. This message can be overridden with state->resolvemsg.
1175  */
1176 static void NORETURN die_user_resolve(const struct am_state *state)
1177 {
1178         if (state->resolvemsg) {
1179                 printf_ln("%s", state->resolvemsg);
1180         } else {
1181                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1182
1183                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1184                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1185                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1186         }
1187
1188         exit(128);
1189 }
1190
1191 /**
1192  * Appends signoff to the "msg" field of the am_state.
1193  */
1194 static void am_append_signoff(struct am_state *state)
1195 {
1196         struct strbuf sb = STRBUF_INIT;
1197
1198         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1199         append_signoff(&sb, 0, 0);
1200         state->msg = strbuf_detach(&sb, &state->msg_len);
1201 }
1202
1203 /**
1204  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1205  * state->msg will be set to the patch message. state->author_name,
1206  * state->author_email and state->author_date will be set to the patch author's
1207  * name, email and date respectively. The patch body will be written to the
1208  * state directory's "patch" file.
1209  *
1210  * Returns 1 if the patch should be skipped, 0 otherwise.
1211  */
1212 static int parse_mail(struct am_state *state, const char *mail)
1213 {
1214         FILE *fp;
1215         struct strbuf sb = STRBUF_INIT;
1216         struct strbuf msg = STRBUF_INIT;
1217         struct strbuf author_name = STRBUF_INIT;
1218         struct strbuf author_date = STRBUF_INIT;
1219         struct strbuf author_email = STRBUF_INIT;
1220         int ret = 0;
1221         struct mailinfo mi;
1222
1223         setup_mailinfo(&mi);
1224
1225         if (state->utf8)
1226                 mi.metainfo_charset = get_commit_output_encoding();
1227         else
1228                 mi.metainfo_charset = NULL;
1229
1230         switch (state->keep) {
1231         case KEEP_FALSE:
1232                 break;
1233         case KEEP_TRUE:
1234                 mi.keep_subject = 1;
1235                 break;
1236         case KEEP_NON_PATCH:
1237                 mi.keep_non_patch_brackets_in_subject = 1;
1238                 break;
1239         default:
1240                 die("BUG: invalid value for state->keep");
1241         }
1242
1243         if (state->message_id)
1244                 mi.add_message_id = 1;
1245
1246         switch (state->scissors) {
1247         case SCISSORS_UNSET:
1248                 break;
1249         case SCISSORS_FALSE:
1250                 mi.use_scissors = 0;
1251                 break;
1252         case SCISSORS_TRUE:
1253                 mi.use_scissors = 1;
1254                 break;
1255         default:
1256                 die("BUG: invalid value for state->scissors");
1257         }
1258
1259         mi.input = xfopen(mail, "r");
1260         mi.output = xfopen(am_path(state, "info"), "w");
1261         if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
1262                 die("could not parse patch");
1263
1264         fclose(mi.input);
1265         fclose(mi.output);
1266
1267         /* Extract message and author information */
1268         fp = xfopen(am_path(state, "info"), "r");
1269         while (!strbuf_getline_lf(&sb, fp)) {
1270                 const char *x;
1271
1272                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1273                         if (msg.len)
1274                                 strbuf_addch(&msg, '\n');
1275                         strbuf_addstr(&msg, x);
1276                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1277                         strbuf_addstr(&author_name, x);
1278                 else if (skip_prefix(sb.buf, "Email: ", &x))
1279                         strbuf_addstr(&author_email, x);
1280                 else if (skip_prefix(sb.buf, "Date: ", &x))
1281                         strbuf_addstr(&author_date, x);
1282         }
1283         fclose(fp);
1284
1285         /* Skip pine's internal folder data */
1286         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1287                 ret = 1;
1288                 goto finish;
1289         }
1290
1291         if (is_empty_file(am_path(state, "patch"))) {
1292                 printf_ln(_("Patch is empty."));
1293                 die_user_resolve(state);
1294         }
1295
1296         strbuf_addstr(&msg, "\n\n");
1297         strbuf_addbuf(&msg, &mi.log_message);
1298         strbuf_stripspace(&msg, 0);
1299
1300         assert(!state->author_name);
1301         state->author_name = strbuf_detach(&author_name, NULL);
1302
1303         assert(!state->author_email);
1304         state->author_email = strbuf_detach(&author_email, NULL);
1305
1306         assert(!state->author_date);
1307         state->author_date = strbuf_detach(&author_date, NULL);
1308
1309         assert(!state->msg);
1310         state->msg = strbuf_detach(&msg, &state->msg_len);
1311
1312 finish:
1313         strbuf_release(&msg);
1314         strbuf_release(&author_date);
1315         strbuf_release(&author_email);
1316         strbuf_release(&author_name);
1317         strbuf_release(&sb);
1318         clear_mailinfo(&mi);
1319         return ret;
1320 }
1321
1322 /**
1323  * Sets commit_id to the commit hash where the mail was generated from.
1324  * Returns 0 on success, -1 on failure.
1325  */
1326 static int get_mail_commit_oid(struct object_id *commit_id, const char *mail)
1327 {
1328         struct strbuf sb = STRBUF_INIT;
1329         FILE *fp = xfopen(mail, "r");
1330         const char *x;
1331         int ret = 0;
1332
1333         if (strbuf_getline_lf(&sb, fp) ||
1334             !skip_prefix(sb.buf, "From ", &x) ||
1335             get_oid_hex(x, commit_id) < 0)
1336                 ret = -1;
1337
1338         strbuf_release(&sb);
1339         fclose(fp);
1340         return ret;
1341 }
1342
1343 /**
1344  * Sets state->msg, state->author_name, state->author_email, state->author_date
1345  * to the commit's respective info.
1346  */
1347 static void get_commit_info(struct am_state *state, struct commit *commit)
1348 {
1349         const char *buffer, *ident_line, *msg;
1350         size_t ident_len;
1351         struct ident_split id;
1352
1353         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1354
1355         ident_line = find_commit_header(buffer, "author", &ident_len);
1356
1357         if (split_ident_line(&id, ident_line, ident_len) < 0)
1358                 die(_("invalid ident line: %.*s"), (int)ident_len, ident_line);
1359
1360         assert(!state->author_name);
1361         if (id.name_begin)
1362                 state->author_name =
1363                         xmemdupz(id.name_begin, id.name_end - id.name_begin);
1364         else
1365                 state->author_name = xstrdup("");
1366
1367         assert(!state->author_email);
1368         if (id.mail_begin)
1369                 state->author_email =
1370                         xmemdupz(id.mail_begin, id.mail_end - id.mail_begin);
1371         else
1372                 state->author_email = xstrdup("");
1373
1374         assert(!state->author_date);
1375         state->author_date = xstrdup(show_ident_date(&id, DATE_MODE(NORMAL)));
1376
1377         assert(!state->msg);
1378         msg = strstr(buffer, "\n\n");
1379         if (!msg)
1380                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1381         state->msg = xstrdup(msg + 2);
1382         state->msg_len = strlen(state->msg);
1383         unuse_commit_buffer(commit, buffer);
1384 }
1385
1386 /**
1387  * Writes `commit` as a patch to the state directory's "patch" file.
1388  */
1389 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1390 {
1391         struct rev_info rev_info;
1392         FILE *fp;
1393
1394         fp = xfopen(am_path(state, "patch"), "w");
1395         init_revisions(&rev_info, NULL);
1396         rev_info.diff = 1;
1397         rev_info.abbrev = 0;
1398         rev_info.disable_stdin = 1;
1399         rev_info.show_root_diff = 1;
1400         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1401         rev_info.no_commit_id = 1;
1402         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1403         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1404         rev_info.diffopt.use_color = 0;
1405         rev_info.diffopt.file = fp;
1406         rev_info.diffopt.close_file = 1;
1407         add_pending_object(&rev_info, &commit->object, "");
1408         diff_setup_done(&rev_info.diffopt);
1409         log_tree_commit(&rev_info, commit);
1410 }
1411
1412 /**
1413  * Writes the diff of the index against HEAD as a patch to the state
1414  * directory's "patch" file.
1415  */
1416 static void write_index_patch(const struct am_state *state)
1417 {
1418         struct tree *tree;
1419         struct object_id head;
1420         struct rev_info rev_info;
1421         FILE *fp;
1422
1423         if (!get_sha1_tree("HEAD", head.hash))
1424                 tree = lookup_tree(&head);
1425         else
1426                 tree = lookup_tree(&empty_tree_oid);
1427
1428         fp = xfopen(am_path(state, "patch"), "w");
1429         init_revisions(&rev_info, NULL);
1430         rev_info.diff = 1;
1431         rev_info.disable_stdin = 1;
1432         rev_info.no_commit_id = 1;
1433         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1434         rev_info.diffopt.use_color = 0;
1435         rev_info.diffopt.file = fp;
1436         rev_info.diffopt.close_file = 1;
1437         add_pending_object(&rev_info, &tree->object, "");
1438         diff_setup_done(&rev_info.diffopt);
1439         run_diff_index(&rev_info, 1);
1440 }
1441
1442 /**
1443  * Like parse_mail(), but parses the mail by looking up its commit ID
1444  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1445  * of patches.
1446  *
1447  * state->orig_commit will be set to the original commit ID.
1448  *
1449  * Will always return 0 as the patch should never be skipped.
1450  */
1451 static int parse_mail_rebase(struct am_state *state, const char *mail)
1452 {
1453         struct commit *commit;
1454         struct object_id commit_oid;
1455
1456         if (get_mail_commit_oid(&commit_oid, mail) < 0)
1457                 die(_("could not parse %s"), mail);
1458
1459         commit = lookup_commit_or_die(&commit_oid, mail);
1460
1461         get_commit_info(state, commit);
1462
1463         write_commit_patch(state, commit);
1464
1465         oidcpy(&state->orig_commit, &commit_oid);
1466         write_state_text(state, "original-commit", oid_to_hex(&commit_oid));
1467
1468         return 0;
1469 }
1470
1471 /**
1472  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1473  * `index_file` is not NULL, the patch will be applied to that index.
1474  */
1475 static int run_apply(const struct am_state *state, const char *index_file)
1476 {
1477         struct argv_array apply_paths = ARGV_ARRAY_INIT;
1478         struct argv_array apply_opts = ARGV_ARRAY_INIT;
1479         struct apply_state apply_state;
1480         int res, opts_left;
1481         static struct lock_file lock_file;
1482         int force_apply = 0;
1483         int options = 0;
1484
1485         if (init_apply_state(&apply_state, NULL, &lock_file))
1486                 die("BUG: init_apply_state() failed");
1487
1488         argv_array_push(&apply_opts, "apply");
1489         argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
1490
1491         opts_left = apply_parse_options(apply_opts.argc, apply_opts.argv,
1492                                         &apply_state, &force_apply, &options,
1493                                         NULL);
1494
1495         if (opts_left != 0)
1496                 die("unknown option passed through to git apply");
1497
1498         if (index_file) {
1499                 apply_state.index_file = index_file;
1500                 apply_state.cached = 1;
1501         } else
1502                 apply_state.check_index = 1;
1503
1504         /*
1505          * If we are allowed to fall back on 3-way merge, don't give false
1506          * errors during the initial attempt.
1507          */
1508         if (state->threeway && !index_file)
1509                 apply_state.apply_verbosity = verbosity_silent;
1510
1511         if (check_apply_state(&apply_state, force_apply))
1512                 die("BUG: check_apply_state() failed");
1513
1514         argv_array_push(&apply_paths, am_path(state, "patch"));
1515
1516         res = apply_all_patches(&apply_state, apply_paths.argc, apply_paths.argv, options);
1517
1518         argv_array_clear(&apply_paths);
1519         argv_array_clear(&apply_opts);
1520         clear_apply_state(&apply_state);
1521
1522         if (res)
1523                 return res;
1524
1525         if (index_file) {
1526                 /* Reload index as apply_all_patches() will have modified it. */
1527                 discard_cache();
1528                 read_cache_from(index_file);
1529         }
1530
1531         return 0;
1532 }
1533
1534 /**
1535  * Builds an index that contains just the blobs needed for a 3way merge.
1536  */
1537 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1538 {
1539         struct child_process cp = CHILD_PROCESS_INIT;
1540
1541         cp.git_cmd = 1;
1542         argv_array_push(&cp.args, "apply");
1543         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1544         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1545         argv_array_push(&cp.args, am_path(state, "patch"));
1546
1547         if (run_command(&cp))
1548                 return -1;
1549
1550         return 0;
1551 }
1552
1553 /**
1554  * Attempt a threeway merge, using index_path as the temporary index.
1555  */
1556 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1557 {
1558         struct object_id orig_tree, their_tree, our_tree;
1559         const struct object_id *bases[1] = { &orig_tree };
1560         struct merge_options o;
1561         struct commit *result;
1562         char *their_tree_name;
1563
1564         if (get_oid("HEAD", &our_tree) < 0)
1565                 hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
1566
1567         if (build_fake_ancestor(state, index_path))
1568                 return error("could not build fake ancestor");
1569
1570         discard_cache();
1571         read_cache_from(index_path);
1572
1573         if (write_index_as_tree(orig_tree.hash, &the_index, index_path, 0, NULL))
1574                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1575
1576         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1577
1578         if (!state->quiet) {
1579                 /*
1580                  * List paths that needed 3-way fallback, so that the user can
1581                  * review them with extra care to spot mismerges.
1582                  */
1583                 struct rev_info rev_info;
1584                 const char *diff_filter_str = "--diff-filter=AM";
1585
1586                 init_revisions(&rev_info, NULL);
1587                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1588                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1589                 add_pending_oid(&rev_info, "HEAD", &our_tree, 0);
1590                 diff_setup_done(&rev_info.diffopt);
1591                 run_diff_index(&rev_info, 1);
1592         }
1593
1594         if (run_apply(state, index_path))
1595                 return error(_("Did you hand edit your patch?\n"
1596                                 "It does not apply to blobs recorded in its index."));
1597
1598         if (write_index_as_tree(their_tree.hash, &the_index, index_path, 0, NULL))
1599                 return error("could not write tree");
1600
1601         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1602
1603         discard_cache();
1604         read_cache();
1605
1606         /*
1607          * This is not so wrong. Depending on which base we picked, orig_tree
1608          * may be wildly different from ours, but their_tree has the same set of
1609          * wildly different changes in parts the patch did not touch, so
1610          * recursive ends up canceling them, saying that we reverted all those
1611          * changes.
1612          */
1613
1614         init_merge_options(&o);
1615
1616         o.branch1 = "HEAD";
1617         their_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
1618         o.branch2 = their_tree_name;
1619
1620         if (state->quiet)
1621                 o.verbosity = 0;
1622
1623         if (merge_recursive_generic(&o, &our_tree, &their_tree, 1, bases, &result)) {
1624                 rerere(state->allow_rerere_autoupdate);
1625                 free(their_tree_name);
1626                 return error(_("Failed to merge in the changes."));
1627         }
1628
1629         free(their_tree_name);
1630         return 0;
1631 }
1632
1633 /**
1634  * Commits the current index with state->msg as the commit message and
1635  * state->author_name, state->author_email and state->author_date as the author
1636  * information.
1637  */
1638 static void do_commit(const struct am_state *state)
1639 {
1640         struct object_id tree, parent, commit;
1641         const struct object_id *old_oid;
1642         struct commit_list *parents = NULL;
1643         const char *reflog_msg, *author;
1644         struct strbuf sb = STRBUF_INIT;
1645
1646         if (run_hook_le(NULL, "pre-applypatch", NULL))
1647                 exit(1);
1648
1649         if (write_cache_as_tree(tree.hash, 0, NULL))
1650                 die(_("git write-tree failed to write a tree"));
1651
1652         if (!get_sha1_commit("HEAD", parent.hash)) {
1653                 old_oid = &parent;
1654                 commit_list_insert(lookup_commit(&parent), &parents);
1655         } else {
1656                 old_oid = NULL;
1657                 say(state, stderr, _("applying to an empty history"));
1658         }
1659
1660         author = fmt_ident(state->author_name, state->author_email,
1661                         state->ignore_date ? NULL : state->author_date,
1662                         IDENT_STRICT);
1663
1664         if (state->committer_date_is_author_date)
1665                 setenv("GIT_COMMITTER_DATE",
1666                         state->ignore_date ? "" : state->author_date, 1);
1667
1668         if (commit_tree(state->msg, state->msg_len, tree.hash, parents, commit.hash,
1669                                 author, state->sign_commit))
1670                 die(_("failed to write commit object"));
1671
1672         reflog_msg = getenv("GIT_REFLOG_ACTION");
1673         if (!reflog_msg)
1674                 reflog_msg = "am";
1675
1676         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1677                         state->msg);
1678
1679         update_ref_oid(sb.buf, "HEAD", &commit, old_oid, 0,
1680                         UPDATE_REFS_DIE_ON_ERR);
1681
1682         if (state->rebasing) {
1683                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1684
1685                 assert(!is_null_oid(&state->orig_commit));
1686                 fprintf(fp, "%s ", oid_to_hex(&state->orig_commit));
1687                 fprintf(fp, "%s\n", oid_to_hex(&commit));
1688                 fclose(fp);
1689         }
1690
1691         run_hook_le(NULL, "post-applypatch", NULL);
1692
1693         strbuf_release(&sb);
1694 }
1695
1696 /**
1697  * Validates the am_state for resuming -- the "msg" and authorship fields must
1698  * be filled up.
1699  */
1700 static void validate_resume_state(const struct am_state *state)
1701 {
1702         if (!state->msg)
1703                 die(_("cannot resume: %s does not exist."),
1704                         am_path(state, "final-commit"));
1705
1706         if (!state->author_name || !state->author_email || !state->author_date)
1707                 die(_("cannot resume: %s does not exist."),
1708                         am_path(state, "author-script"));
1709 }
1710
1711 /**
1712  * Interactively prompt the user on whether the current patch should be
1713  * applied.
1714  *
1715  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1716  * skip it.
1717  */
1718 static int do_interactive(struct am_state *state)
1719 {
1720         assert(state->msg);
1721
1722         if (!isatty(0))
1723                 die(_("cannot be interactive without stdin connected to a terminal."));
1724
1725         for (;;) {
1726                 const char *reply;
1727
1728                 puts(_("Commit Body is:"));
1729                 puts("--------------------------");
1730                 printf("%s", state->msg);
1731                 puts("--------------------------");
1732
1733                 /*
1734                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1735                  * in your translation. The program will only accept English
1736                  * input at this point.
1737                  */
1738                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1739
1740                 if (!reply) {
1741                         continue;
1742                 } else if (*reply == 'y' || *reply == 'Y') {
1743                         return 0;
1744                 } else if (*reply == 'a' || *reply == 'A') {
1745                         state->interactive = 0;
1746                         return 0;
1747                 } else if (*reply == 'n' || *reply == 'N') {
1748                         return 1;
1749                 } else if (*reply == 'e' || *reply == 'E') {
1750                         struct strbuf msg = STRBUF_INIT;
1751
1752                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1753                                 free(state->msg);
1754                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1755                         }
1756                         strbuf_release(&msg);
1757                 } else if (*reply == 'v' || *reply == 'V') {
1758                         const char *pager = git_pager(1);
1759                         struct child_process cp = CHILD_PROCESS_INIT;
1760
1761                         if (!pager)
1762                                 pager = "cat";
1763                         prepare_pager_args(&cp, pager);
1764                         argv_array_push(&cp.args, am_path(state, "patch"));
1765                         run_command(&cp);
1766                 }
1767         }
1768 }
1769
1770 /**
1771  * Applies all queued mail.
1772  *
1773  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1774  * well as the state directory's "patch" file is used as-is for applying the
1775  * patch and committing it.
1776  */
1777 static void am_run(struct am_state *state, int resume)
1778 {
1779         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1780         struct strbuf sb = STRBUF_INIT;
1781
1782         unlink(am_path(state, "dirtyindex"));
1783
1784         refresh_and_write_cache();
1785
1786         if (index_has_changes(&sb)) {
1787                 write_state_bool(state, "dirtyindex", 1);
1788                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1789         }
1790
1791         strbuf_release(&sb);
1792
1793         while (state->cur <= state->last) {
1794                 const char *mail = am_path(state, msgnum(state));
1795                 int apply_status;
1796
1797                 reset_ident_date();
1798
1799                 if (!file_exists(mail))
1800                         goto next;
1801
1802                 if (resume) {
1803                         validate_resume_state(state);
1804                 } else {
1805                         int skip;
1806
1807                         if (state->rebasing)
1808                                 skip = parse_mail_rebase(state, mail);
1809                         else
1810                                 skip = parse_mail(state, mail);
1811
1812                         if (skip)
1813                                 goto next; /* mail should be skipped */
1814
1815                         if (state->signoff)
1816                                 am_append_signoff(state);
1817
1818                         write_author_script(state);
1819                         write_commit_msg(state);
1820                 }
1821
1822                 if (state->interactive && do_interactive(state))
1823                         goto next;
1824
1825                 if (run_applypatch_msg_hook(state))
1826                         exit(1);
1827
1828                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1829
1830                 apply_status = run_apply(state, NULL);
1831
1832                 if (apply_status && state->threeway) {
1833                         struct strbuf sb = STRBUF_INIT;
1834
1835                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1836                         apply_status = fall_back_threeway(state, sb.buf);
1837                         strbuf_release(&sb);
1838
1839                         /*
1840                          * Applying the patch to an earlier tree and merging
1841                          * the result may have produced the same tree as ours.
1842                          */
1843                         if (!apply_status && !index_has_changes(NULL)) {
1844                                 say(state, stdout, _("No changes -- Patch already applied."));
1845                                 goto next;
1846                         }
1847                 }
1848
1849                 if (apply_status) {
1850                         int advice_amworkdir = 1;
1851
1852                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1853                                 linelen(state->msg), state->msg);
1854
1855                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1856
1857                         if (advice_amworkdir)
1858                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1859                                                 am_path(state, "patch"));
1860
1861                         die_user_resolve(state);
1862                 }
1863
1864                 do_commit(state);
1865
1866 next:
1867                 am_next(state);
1868
1869                 if (resume)
1870                         am_load(state);
1871                 resume = 0;
1872         }
1873
1874         if (!is_empty_file(am_path(state, "rewritten"))) {
1875                 assert(state->rebasing);
1876                 copy_notes_for_rebase(state);
1877                 run_post_rewrite_hook(state);
1878         }
1879
1880         /*
1881          * In rebasing mode, it's up to the caller to take care of
1882          * housekeeping.
1883          */
1884         if (!state->rebasing) {
1885                 am_destroy(state);
1886                 close_all_packs();
1887                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1888         }
1889 }
1890
1891 /**
1892  * Resume the current am session after patch application failure. The user did
1893  * all the hard work, and we do not have to do any patch application. Just
1894  * trust and commit what the user has in the index and working tree.
1895  */
1896 static void am_resolve(struct am_state *state)
1897 {
1898         validate_resume_state(state);
1899
1900         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1901
1902         if (!index_has_changes(NULL)) {
1903                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1904                         "If there is nothing left to stage, chances are that something else\n"
1905                         "already introduced the same changes; you might want to skip this patch."));
1906                 die_user_resolve(state);
1907         }
1908
1909         if (unmerged_cache()) {
1910                 printf_ln(_("You still have unmerged paths in your index.\n"
1911                         "You should 'git add' each file with resolved conflicts to mark them as such.\n"
1912                         "You might run `git rm` on a file to accept \"deleted by them\" for it."));
1913                 die_user_resolve(state);
1914         }
1915
1916         if (state->interactive) {
1917                 write_index_patch(state);
1918                 if (do_interactive(state))
1919                         goto next;
1920         }
1921
1922         rerere(0);
1923
1924         do_commit(state);
1925
1926 next:
1927         am_next(state);
1928         am_load(state);
1929         am_run(state, 0);
1930 }
1931
1932 /**
1933  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1934  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1935  * failure.
1936  */
1937 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1938 {
1939         struct lock_file *lock_file;
1940         struct unpack_trees_options opts;
1941         struct tree_desc t[2];
1942
1943         if (parse_tree(head) || parse_tree(remote))
1944                 return -1;
1945
1946         lock_file = xcalloc(1, sizeof(struct lock_file));
1947         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1948
1949         refresh_cache(REFRESH_QUIET);
1950
1951         memset(&opts, 0, sizeof(opts));
1952         opts.head_idx = 1;
1953         opts.src_index = &the_index;
1954         opts.dst_index = &the_index;
1955         opts.update = 1;
1956         opts.merge = 1;
1957         opts.reset = reset;
1958         opts.fn = twoway_merge;
1959         init_tree_desc(&t[0], head->buffer, head->size);
1960         init_tree_desc(&t[1], remote->buffer, remote->size);
1961
1962         if (unpack_trees(2, t, &opts)) {
1963                 rollback_lock_file(lock_file);
1964                 return -1;
1965         }
1966
1967         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1968                 die(_("unable to write new index file"));
1969
1970         return 0;
1971 }
1972
1973 /**
1974  * Merges a tree into the index. The index's stat info will take precedence
1975  * over the merged tree's. Returns 0 on success, -1 on failure.
1976  */
1977 static int merge_tree(struct tree *tree)
1978 {
1979         struct lock_file *lock_file;
1980         struct unpack_trees_options opts;
1981         struct tree_desc t[1];
1982
1983         if (parse_tree(tree))
1984                 return -1;
1985
1986         lock_file = xcalloc(1, sizeof(struct lock_file));
1987         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1988
1989         memset(&opts, 0, sizeof(opts));
1990         opts.head_idx = 1;
1991         opts.src_index = &the_index;
1992         opts.dst_index = &the_index;
1993         opts.merge = 1;
1994         opts.fn = oneway_merge;
1995         init_tree_desc(&t[0], tree->buffer, tree->size);
1996
1997         if (unpack_trees(1, t, &opts)) {
1998                 rollback_lock_file(lock_file);
1999                 return -1;
2000         }
2001
2002         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2003                 die(_("unable to write new index file"));
2004
2005         return 0;
2006 }
2007
2008 /**
2009  * Clean the index without touching entries that are not modified between
2010  * `head` and `remote`.
2011  */
2012 static int clean_index(const struct object_id *head, const struct object_id *remote)
2013 {
2014         struct tree *head_tree, *remote_tree, *index_tree;
2015         struct object_id index;
2016
2017         head_tree = parse_tree_indirect(head);
2018         if (!head_tree)
2019                 return error(_("Could not parse object '%s'."), oid_to_hex(head));
2020
2021         remote_tree = parse_tree_indirect(remote);
2022         if (!remote_tree)
2023                 return error(_("Could not parse object '%s'."), oid_to_hex(remote));
2024
2025         read_cache_unmerged();
2026
2027         if (fast_forward_to(head_tree, head_tree, 1))
2028                 return -1;
2029
2030         if (write_cache_as_tree(index.hash, 0, NULL))
2031                 return -1;
2032
2033         index_tree = parse_tree_indirect(&index);
2034         if (!index_tree)
2035                 return error(_("Could not parse object '%s'."), oid_to_hex(&index));
2036
2037         if (fast_forward_to(index_tree, remote_tree, 0))
2038                 return -1;
2039
2040         if (merge_tree(remote_tree))
2041                 return -1;
2042
2043         remove_branch_state();
2044
2045         return 0;
2046 }
2047
2048 /**
2049  * Resets rerere's merge resolution metadata.
2050  */
2051 static void am_rerere_clear(void)
2052 {
2053         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2054         rerere_clear(&merge_rr);
2055         string_list_clear(&merge_rr, 1);
2056 }
2057
2058 /**
2059  * Resume the current am session by skipping the current patch.
2060  */
2061 static void am_skip(struct am_state *state)
2062 {
2063         struct object_id head;
2064
2065         am_rerere_clear();
2066
2067         if (get_oid("HEAD", &head))
2068                 hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
2069
2070         if (clean_index(&head, &head))
2071                 die(_("failed to clean index"));
2072
2073         am_next(state);
2074         am_load(state);
2075         am_run(state, 0);
2076 }
2077
2078 /**
2079  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2080  *
2081  * It is not safe to reset HEAD when:
2082  * 1. git-am previously failed because the index was dirty.
2083  * 2. HEAD has moved since git-am previously failed.
2084  */
2085 static int safe_to_abort(const struct am_state *state)
2086 {
2087         struct strbuf sb = STRBUF_INIT;
2088         struct object_id abort_safety, head;
2089
2090         if (file_exists(am_path(state, "dirtyindex")))
2091                 return 0;
2092
2093         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2094                 if (get_oid_hex(sb.buf, &abort_safety))
2095                         die(_("could not parse %s"), am_path(state, "abort-safety"));
2096         } else
2097                 oidclr(&abort_safety);
2098
2099         if (get_oid("HEAD", &head))
2100                 oidclr(&head);
2101
2102         if (!oidcmp(&head, &abort_safety))
2103                 return 1;
2104
2105         warning(_("You seem to have moved HEAD since the last 'am' failure.\n"
2106                 "Not rewinding to ORIG_HEAD"));
2107
2108         return 0;
2109 }
2110
2111 /**
2112  * Aborts the current am session if it is safe to do so.
2113  */
2114 static void am_abort(struct am_state *state)
2115 {
2116         struct object_id curr_head, orig_head;
2117         int has_curr_head, has_orig_head;
2118         char *curr_branch;
2119
2120         if (!safe_to_abort(state)) {
2121                 am_destroy(state);
2122                 return;
2123         }
2124
2125         am_rerere_clear();
2126
2127         curr_branch = resolve_refdup("HEAD", 0, curr_head.hash, NULL);
2128         has_curr_head = curr_branch && !is_null_oid(&curr_head);
2129         if (!has_curr_head)
2130                 hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
2131
2132         has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
2133         if (!has_orig_head)
2134                 hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
2135
2136         clean_index(&curr_head, &orig_head);
2137
2138         if (has_orig_head)
2139                 update_ref_oid("am --abort", "HEAD", &orig_head,
2140                                 has_curr_head ? &curr_head : NULL, 0,
2141                                 UPDATE_REFS_DIE_ON_ERR);
2142         else if (curr_branch)
2143                 delete_ref(NULL, curr_branch, NULL, REF_NODEREF);
2144
2145         free(curr_branch);
2146         am_destroy(state);
2147 }
2148
2149 /**
2150  * parse_options() callback that validates and sets opt->value to the
2151  * PATCH_FORMAT_* enum value corresponding to `arg`.
2152  */
2153 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2154 {
2155         int *opt_value = opt->value;
2156
2157         if (!strcmp(arg, "mbox"))
2158                 *opt_value = PATCH_FORMAT_MBOX;
2159         else if (!strcmp(arg, "stgit"))
2160                 *opt_value = PATCH_FORMAT_STGIT;
2161         else if (!strcmp(arg, "stgit-series"))
2162                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2163         else if (!strcmp(arg, "hg"))
2164                 *opt_value = PATCH_FORMAT_HG;
2165         else if (!strcmp(arg, "mboxrd"))
2166                 *opt_value = PATCH_FORMAT_MBOXRD;
2167         else
2168                 return error(_("Invalid value for --patch-format: %s"), arg);
2169         return 0;
2170 }
2171
2172 enum resume_mode {
2173         RESUME_FALSE = 0,
2174         RESUME_APPLY,
2175         RESUME_RESOLVED,
2176         RESUME_SKIP,
2177         RESUME_ABORT
2178 };
2179
2180 static int git_am_config(const char *k, const char *v, void *cb)
2181 {
2182         int status;
2183
2184         status = git_gpg_config(k, v, NULL);
2185         if (status)
2186                 return status;
2187
2188         return git_default_config(k, v, NULL);
2189 }
2190
2191 int cmd_am(int argc, const char **argv, const char *prefix)
2192 {
2193         struct am_state state;
2194         int binary = -1;
2195         int keep_cr = -1;
2196         int patch_format = PATCH_FORMAT_UNKNOWN;
2197         enum resume_mode resume = RESUME_FALSE;
2198         int in_progress;
2199
2200         const char * const usage[] = {
2201                 N_("git am [<options>] [(<mbox> | <Maildir>)...]"),
2202                 N_("git am [<options>] (--continue | --skip | --abort)"),
2203                 NULL
2204         };
2205
2206         struct option options[] = {
2207                 OPT_BOOL('i', "interactive", &state.interactive,
2208                         N_("run interactively")),
2209                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2210                         N_("historical option -- no-op")),
2211                 OPT_BOOL('3', "3way", &state.threeway,
2212                         N_("allow fall back on 3way merging if needed")),
2213                 OPT__QUIET(&state.quiet, N_("be quiet")),
2214                 OPT_SET_INT('s', "signoff", &state.signoff,
2215                         N_("add a Signed-off-by line to the commit message"),
2216                         SIGNOFF_EXPLICIT),
2217                 OPT_BOOL('u', "utf8", &state.utf8,
2218                         N_("recode into utf8 (default)")),
2219                 OPT_SET_INT('k', "keep", &state.keep,
2220                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2221                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2222                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2223                 OPT_BOOL('m', "message-id", &state.message_id,
2224                         N_("pass -m flag to git-mailinfo")),
2225                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2226                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2227                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2228                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2229                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2230                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2231                 OPT_BOOL('c', "scissors", &state.scissors,
2232                         N_("strip everything before a scissors line")),
2233                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2234                         N_("pass it through git-apply"),
2235                         0),
2236                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2237                         N_("pass it through git-apply"),
2238                         PARSE_OPT_NOARG),
2239                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2240                         N_("pass it through git-apply"),
2241                         PARSE_OPT_NOARG),
2242                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2243                         N_("pass it through git-apply"),
2244                         0),
2245                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2246                         N_("pass it through git-apply"),
2247                         0),
2248                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2249                         N_("pass it through git-apply"),
2250                         0),
2251                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2252                         N_("pass it through git-apply"),
2253                         0),
2254                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2255                         N_("pass it through git-apply"),
2256                         0),
2257                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2258                         N_("format the patch(es) are in"),
2259                         parse_opt_patchformat),
2260                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2261                         N_("pass it through git-apply"),
2262                         PARSE_OPT_NOARG),
2263                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2264                         N_("override error message when patch failure occurs")),
2265                 OPT_CMDMODE(0, "continue", &resume,
2266                         N_("continue applying patches after resolving a conflict"),
2267                         RESUME_RESOLVED),
2268                 OPT_CMDMODE('r', "resolved", &resume,
2269                         N_("synonyms for --continue"),
2270                         RESUME_RESOLVED),
2271                 OPT_CMDMODE(0, "skip", &resume,
2272                         N_("skip the current patch"),
2273                         RESUME_SKIP),
2274                 OPT_CMDMODE(0, "abort", &resume,
2275                         N_("restore the original branch and abort the patching operation."),
2276                         RESUME_ABORT),
2277                 OPT_BOOL(0, "committer-date-is-author-date",
2278                         &state.committer_date_is_author_date,
2279                         N_("lie about committer date")),
2280                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2281                         N_("use current timestamp for author date")),
2282                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2283                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2284                   N_("GPG-sign commits"),
2285                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2286                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2287                         N_("(internal use for git-rebase)")),
2288                 OPT_END()
2289         };
2290
2291         if (argc == 2 && !strcmp(argv[1], "-h"))
2292                 usage_with_options(usage, options);
2293
2294         git_config(git_am_config, NULL);
2295
2296         am_state_init(&state);
2297
2298         in_progress = am_in_progress(&state);
2299         if (in_progress)
2300                 am_load(&state);
2301
2302         argc = parse_options(argc, argv, prefix, options, usage, 0);
2303
2304         if (binary >= 0)
2305                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2306                                 "it will be removed. Please do not use it anymore."));
2307
2308         /* Ensure a valid committer ident can be constructed */
2309         git_committer_info(IDENT_STRICT);
2310
2311         if (read_index_preload(&the_index, NULL) < 0)
2312                 die(_("failed to read the index"));
2313
2314         if (in_progress) {
2315                 /*
2316                  * Catch user error to feed us patches when there is a session
2317                  * in progress:
2318                  *
2319                  * 1. mbox path(s) are provided on the command-line.
2320                  * 2. stdin is not a tty: the user is trying to feed us a patch
2321                  *    from standard input. This is somewhat unreliable -- stdin
2322                  *    could be /dev/null for example and the caller did not
2323                  *    intend to feed us a patch but wanted to continue
2324                  *    unattended.
2325                  */
2326                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2327                         die(_("previous rebase directory %s still exists but mbox given."),
2328                                 state.dir);
2329
2330                 if (resume == RESUME_FALSE)
2331                         resume = RESUME_APPLY;
2332
2333                 if (state.signoff == SIGNOFF_EXPLICIT)
2334                         am_append_signoff(&state);
2335         } else {
2336                 struct argv_array paths = ARGV_ARRAY_INIT;
2337                 int i;
2338
2339                 /*
2340                  * Handle stray state directory in the independent-run case. In
2341                  * the --rebasing case, it is up to the caller to take care of
2342                  * stray directories.
2343                  */
2344                 if (file_exists(state.dir) && !state.rebasing) {
2345                         if (resume == RESUME_ABORT) {
2346                                 am_destroy(&state);
2347                                 am_state_release(&state);
2348                                 return 0;
2349                         }
2350
2351                         die(_("Stray %s directory found.\n"
2352                                 "Use \"git am --abort\" to remove it."),
2353                                 state.dir);
2354                 }
2355
2356                 if (resume)
2357                         die(_("Resolve operation not in progress, we are not resuming."));
2358
2359                 for (i = 0; i < argc; i++) {
2360                         if (is_absolute_path(argv[i]) || !prefix)
2361                                 argv_array_push(&paths, argv[i]);
2362                         else
2363                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2364                 }
2365
2366                 am_setup(&state, patch_format, paths.argv, keep_cr);
2367
2368                 argv_array_clear(&paths);
2369         }
2370
2371         switch (resume) {
2372         case RESUME_FALSE:
2373                 am_run(&state, 0);
2374                 break;
2375         case RESUME_APPLY:
2376                 am_run(&state, 1);
2377                 break;
2378         case RESUME_RESOLVED:
2379                 am_resolve(&state);
2380                 break;
2381         case RESUME_SKIP:
2382                 am_skip(&state);
2383                 break;
2384         case RESUME_ABORT:
2385                 am_abort(&state);
2386                 break;
2387         default:
2388                 die("BUG: invalid resume value");
2389         }
2390
2391         am_state_release(&state);
2392
2393         return 0;
2394 }