git.oblomov.eu Git - git/blob - 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 "builtin.h"
   8 #include "exec_cmd.h"
   9 #include "parse-options.h"
  10 #include "dir.h"
  11 #include "run-command.h"
  12 #include "quote.h"
  13 #include "tempfile.h"
  14 #include "lockfile.h"
  15 #include "cache-tree.h"
  16 #include "refs.h"
  17 #include "commit.h"
  18 #include "diff.h"
  19 #include "diffcore.h"
  20 #include "unpack-trees.h"
  21 #include "branch.h"
  22 #include "sequencer.h"
  23 #include "revision.h"
  24 #include "merge-recursive.h"
  25 #include "revision.h"
  26 #include "log-tree.h"
  27 #include "notes-utils.h"
  28 #include "rerere.h"
  29 #include "prompt.h"
  30 #include "mailinfo.h"
  31 #include "apply.h"
  32 #include "string-list.h"
  33
  34 /**
  35  * Returns 1 if the file is empty or does not exist, 0 otherwise.
  36  */
  37 static int is_empty_file(const char *filename)
  38 {
  39         struct stat st;
  40
  41         if (stat(filename, &st) < 0) {
  42                 if (errno == ENOENT)
  43                         return 1;
  44                 die_errno(_("could not stat %s"), filename);
  45         }
  46
  47         return !st.st_size;
  48 }
  49
  50 /**
  51  * Returns the length of the first line of msg.
  52  */
  53 static int linelen(const char *msg)
  54 {
  55         return strchrnul(msg, '\n') - msg;
  56 }
  57
  58 /**
  59  * Returns true if `str` consists of only whitespace, false otherwise.
  60  */
  61 static int str_isspace(const char *str)
  62 {
  63         for (; *str; str++)
  64                 if (!isspace(*str))
  65                         return 0;
  66
  67         return 1;
  68 }
  69
  70 enum patch_format {
  71         PATCH_FORMAT_UNKNOWN = 0,
  72         PATCH_FORMAT_MBOX,
  73         PATCH_FORMAT_STGIT,
  74         PATCH_FORMAT_STGIT_SERIES,
  75         PATCH_FORMAT_HG,
  76         PATCH_FORMAT_MBOXRD
  77 };
  78
  79 enum keep_type {
  80         KEEP_FALSE = 0,
  81         KEEP_TRUE,      /* pass -k flag to git-mailinfo */
  82         KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
  83 };
  84
  85 enum scissors_type {
  86         SCISSORS_UNSET = -1,
  87         SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
  88         SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
  89 };
  90
  91 enum signoff_type {
  92         SIGNOFF_FALSE = 0,
  93         SIGNOFF_TRUE = 1,
  94         SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
  95 };
  96
  97 struct am_state {
  98         /* state directory path */
  99         char *dir;
 100
 101         /* current and last patch numbers, 1-indexed */
 102         int cur;
 103         int last;
 104
 105         /* commit metadata and message */
 106         char *author_name;
 107         char *author_email;
 108         char *author_date;
 109         char *msg;
 110         size_t msg_len;
 111
 112         /* when --rebasing, records the original commit the patch came from */
 113         struct object_id orig_commit;
 114
 115         /* number of digits in patch filename */
 116         int prec;
 117
 118         /* various operating modes and command line options */
 119         int interactive;
 120         int threeway;
 121         int quiet;
 122         int signoff; /* enum signoff_type */
 123         int utf8;
 124         int keep; /* enum keep_type */
 125         int message_id;
 126         int scissors; /* enum scissors_type */
 127         struct argv_array git_apply_opts;
 128         const char *resolvemsg;
 129         int committer_date_is_author_date;
 130         int ignore_date;
 131         int allow_rerere_autoupdate;
 132         const char *sign_commit;
 133         int rebasing;
 134 };
 135
 136 /**
 137  * Initializes am_state with the default values. The state directory is set to
 138  * dir.
 139  */
 140 static void am_state_init(struct am_state *state, const char *dir)
 141 {
 142         int gpgsign;
 143
 144         memset(state, 0, sizeof(*state));
 145
 146         assert(dir);
 147         state->dir = xstrdup(dir);
 148
 149         state->prec = 4;
 150
 151         git_config_get_bool("am.threeway", &state->threeway);
 152
 153         state->utf8 = 1;
 154
 155         git_config_get_bool("am.messageid", &state->message_id);
 156
 157         state->scissors = SCISSORS_UNSET;
 158
 159         argv_array_init(&state->git_apply_opts);
 160
 161         if (!git_config_get_bool("commit.gpgsign", &gpgsign))
 162                 state->sign_commit = gpgsign ? "" : NULL;
 163 }
 164
 165 /**
 166  * Releases memory allocated by an am_state.
 167  */
 168 static void am_state_release(struct am_state *state)
 169 {
 170         free(state->dir);
 171         free(state->author_name);
 172         free(state->author_email);
 173         free(state->author_date);
 174         free(state->msg);
 175         argv_array_clear(&state->git_apply_opts);
 176 }
 177
 178 /**
 179  * Returns path relative to the am_state directory.
 180  */
 181 static inline const char *am_path(const struct am_state *state, const char *path)
 182 {
 183         return mkpath("%s/%s", state->dir, path);
 184 }
 185
 186 /**
 187  * For convenience to call write_file()
 188  */
 189 static void write_state_text(const struct am_state *state,
 190                              const char *name, const char *string)
 191 {
 192         write_file(am_path(state, name), "%s", string);
 193 }
 194
 195 static void write_state_count(const struct am_state *state,
 196                               const char *name, int value)
 197 {
 198         write_file(am_path(state, name), "%d", value);
 199 }
 200
 201 static void write_state_bool(const struct am_state *state,
 202                              const char *name, int value)
 203 {
 204         write_state_text(state, name, value ? "t" : "f");
 205 }
 206
 207 /**
 208  * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
 209  * at the end.
 210  */
 211 static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
 212 {
 213         va_list ap;
 214
 215         va_start(ap, fmt);
 216         if (!state->quiet) {
 217                 vfprintf(fp, fmt, ap);
 218                 putc('\n', fp);
 219         }
 220         va_end(ap);
 221 }
 222
 223 /**
 224  * Returns 1 if there is an am session in progress, 0 otherwise.
 225  */
 226 static int am_in_progress(const struct am_state *state)
 227 {
 228         struct stat st;
 229
 230         if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
 231                 return 0;
 232         if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
 233                 return 0;
 234         if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
 235                 return 0;
 236         return 1;
 237 }
 238
 239 /**
 240  * Reads the contents of `file` in the `state` directory into `sb`. Returns the
 241  * number of bytes read on success, -1 if the file does not exist. If `trim` is
 242  * set, trailing whitespace will be removed.
 243  */
 244 static int read_state_file(struct strbuf *sb, const struct am_state *state,
 245                         const char *file, int trim)
 246 {
 247         strbuf_reset(sb);
 248
 249         if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
 250                 if (trim)
 251                         strbuf_trim(sb);
 252
 253                 return sb->len;
 254         }
 255
 256         if (errno == ENOENT)
 257                 return -1;
 258
 259         die_errno(_("could not read '%s'"), am_path(state, file));
 260 }
 261
 262 /**
 263  * Take a series of KEY='VALUE' lines where VALUE part is
 264  * sq-quoted, and append <KEY, VALUE> at the end of the string list
 265  */
 266 static int parse_key_value_squoted(char *buf, struct string_list *list)
 267 {
 268         while (*buf) {
 269                 struct string_list_item *item;
 270                 char *np;
 271                 char *cp = strchr(buf, '=');
 272                 if (!cp)
 273                         return -1;
 274                 np = strchrnul(cp, '\n');
 275                 *cp++ = '\0';
 276                 item = string_list_append(list, buf);
 277
 278                 buf = np + (*np == '\n');
 279                 *np = '\0';
 280                 cp = sq_dequote(cp);
 281                 if (!cp)
 282                         return -1;
 283                 item->util = xstrdup(cp);
 284         }
 285         return 0;
 286 }
 287
 288 /**
 289  * Reads and parses the state directory's "author-script" file, and sets
 290  * state->author_name, state->author_email and state->author_date accordingly.
 291  * Returns 0 on success, -1 if the file could not be parsed.
 292  *
 293  * The author script is of the format:
 294  *
 295  *      GIT_AUTHOR_NAME='$author_name'
 296  *      GIT_AUTHOR_EMAIL='$author_email'
 297  *      GIT_AUTHOR_DATE='$author_date'
 298  *
 299  * where $author_name, $author_email and $author_date are quoted. We are strict
 300  * with our parsing, as the file was meant to be eval'd in the old git-am.sh
 301  * script, and thus if the file differs from what this function expects, it is
 302  * better to bail out than to do something that the user does not expect.
 303  */
 304 static int read_author_script(struct am_state *state)
 305 {
 306         const char *filename = am_path(state, "author-script");
 307         struct strbuf buf = STRBUF_INIT;
 308         struct string_list kv = STRING_LIST_INIT_DUP;
 309         int retval = -1; /* assume failure */
 310         int fd;
 311
 312         assert(!state->author_name);
 313         assert(!state->author_email);
 314         assert(!state->author_date);
 315
 316         fd = open(filename, O_RDONLY);
 317         if (fd < 0) {
 318                 if (errno == ENOENT)
 319                         return 0;
 320                 die_errno(_("could not open '%s' for reading"), filename);
 321         }
 322         strbuf_read(&buf, fd, 0);
 323         close(fd);
 324         if (parse_key_value_squoted(buf.buf, &kv))
 325                 goto finish;
 326
 327         if (kv.nr != 3 ||
 328             strcmp(kv.items[0].string, "GIT_AUTHOR_NAME") ||
 329             strcmp(kv.items[1].string, "GIT_AUTHOR_EMAIL") ||
 330             strcmp(kv.items[2].string, "GIT_AUTHOR_DATE"))
 331                 goto finish;
 332         state->author_name = kv.items[0].util;
 333         state->author_email = kv.items[1].util;
 334         state->author_date = kv.items[2].util;
 335         retval = 0;
 336 finish:
 337         string_list_clear(&kv, !!retval);
 338         strbuf_release(&buf);
 339         return retval;
 340 }
 341
 342 /**
 343  * Saves state->author_name, state->author_email and state->author_date in the
 344  * state directory's "author-script" file.
 345  */
 346 static void write_author_script(const struct am_state *state)
 347 {
 348         struct strbuf sb = STRBUF_INIT;
 349
 350         strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
 351         sq_quote_buf(&sb, state->author_name);
 352         strbuf_addch(&sb, '\n');
 353
 354         strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
 355         sq_quote_buf(&sb, state->author_email);
 356         strbuf_addch(&sb, '\n');
 357
 358         strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
 359         sq_quote_buf(&sb, state->author_date);
 360         strbuf_addch(&sb, '\n');
 361
 362         write_state_text(state, "author-script", sb.buf);
 363
 364         strbuf_release(&sb);
 365 }
 366
 367 /**
 368  * Reads the commit message from the state directory's "final-commit" file,
 369  * setting state->msg to its contents and state->msg_len to the length of its
 370  * contents in bytes.
 371  *
 372  * Returns 0 on success, -1 if the file does not exist.
 373  */
 374 static int read_commit_msg(struct am_state *state)
 375 {
 376         struct strbuf sb = STRBUF_INIT;
 377
 378         assert(!state->msg);
 379
 380         if (read_state_file(&sb, state, "final-commit", 0) < 0) {
 381                 strbuf_release(&sb);
 382                 return -1;
 383         }
 384
 385         state->msg = strbuf_detach(&sb, &state->msg_len);
 386         return 0;
 387 }
 388
 389 /**
 390  * Saves state->msg in the state directory's "final-commit" file.
 391  */
 392 static void write_commit_msg(const struct am_state *state)
 393 {
 394         const char *filename = am_path(state, "final-commit");
 395         write_file_buf(filename, state->msg, state->msg_len);
 396 }
 397
 398 /**
 399  * Loads state from disk.
 400  */
 401 static void am_load(struct am_state *state)
 402 {
 403         struct strbuf sb = STRBUF_INIT;
 404
 405         if (read_state_file(&sb, state, "next", 1) < 0)
 406                 die("BUG: state file 'next' does not exist");
 407         state->cur = strtol(sb.buf, NULL, 10);
 408
 409         if (read_state_file(&sb, state, "last", 1) < 0)
 410                 die("BUG: state file 'last' does not exist");
 411         state->last = strtol(sb.buf, NULL, 10);
 412
 413         if (read_author_script(state) < 0)
 414                 die(_("could not parse author script"));
 415
 416         read_commit_msg(state);
 417
 418         if (read_state_file(&sb, state, "original-commit", 1) < 0)
 419                 oidclr(&state->orig_commit);
 420         else if (get_oid_hex(sb.buf, &state->orig_commit) < 0)
 421                 die(_("could not parse %s"), am_path(state, "original-commit"));
 422
 423         read_state_file(&sb, state, "threeway", 1);
 424         state->threeway = !strcmp(sb.buf, "t");
 425
 426         read_state_file(&sb, state, "quiet", 1);
 427         state->quiet = !strcmp(sb.buf, "t");
 428
 429         read_state_file(&sb, state, "sign", 1);
 430         state->signoff = !strcmp(sb.buf, "t");
 431
 432         read_state_file(&sb, state, "utf8", 1);
 433         state->utf8 = !strcmp(sb.buf, "t");
 434
 435         read_state_file(&sb, state, "keep", 1);
 436         if (!strcmp(sb.buf, "t"))
 437                 state->keep = KEEP_TRUE;
 438         else if (!strcmp(sb.buf, "b"))
 439                 state->keep = KEEP_NON_PATCH;
 440         else
 441                 state->keep = KEEP_FALSE;
 442
 443         read_state_file(&sb, state, "messageid", 1);
 444         state->message_id = !strcmp(sb.buf, "t");
 445
 446         read_state_file(&sb, state, "scissors", 1);
 447         if (!strcmp(sb.buf, "t"))
 448                 state->scissors = SCISSORS_TRUE;
 449         else if (!strcmp(sb.buf, "f"))
 450                 state->scissors = SCISSORS_FALSE;
 451         else
 452                 state->scissors = SCISSORS_UNSET;
 453
 454         read_state_file(&sb, state, "apply-opt", 1);
 455         argv_array_clear(&state->git_apply_opts);
 456         if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
 457                 die(_("could not parse %s"), am_path(state, "apply-opt"));
 458
 459         state->rebasing = !!file_exists(am_path(state, "rebasing"));
 460
 461         strbuf_release(&sb);
 462 }
 463
 464 /**
 465  * Removes the am_state directory, forcefully terminating the current am
 466  * session.
 467  */
 468 static void am_destroy(const struct am_state *state)
 469 {
 470         struct strbuf sb = STRBUF_INIT;
 471
 472         strbuf_addstr(&sb, state->dir);
 473         remove_dir_recursively(&sb, 0);
 474         strbuf_release(&sb);
 475 }
 476
 477 /**
 478  * Runs applypatch-msg hook. Returns its exit code.
 479  */
 480 static int run_applypatch_msg_hook(struct am_state *state)
 481 {
 482         int ret;
 483
 484         assert(state->msg);
 485         ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
 486
 487         if (!ret) {
 488                 free(state->msg);
 489                 state->msg = NULL;
 490                 if (read_commit_msg(state) < 0)
 491                         die(_("'%s' was deleted by the applypatch-msg hook"),
 492                                 am_path(state, "final-commit"));
 493         }
 494
 495         return ret;
 496 }
 497
 498 /**
 499  * Runs post-rewrite hook. Returns it exit code.
 500  */
 501 static int run_post_rewrite_hook(const struct am_state *state)
 502 {
 503         struct child_process cp = CHILD_PROCESS_INIT;
 504         const char *hook = find_hook("post-rewrite");
 505         int ret;
 506
 507         if (!hook)
 508                 return 0;
 509
 510         argv_array_push(&cp.args, hook);
 511         argv_array_push(&cp.args, "rebase");
 512
 513         cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
 514         cp.stdout_to_stderr = 1;
 515
 516         ret = run_command(&cp);
 517
 518         close(cp.in);
 519         return ret;
 520 }
 521
 522 /**
 523  * Reads the state directory's "rewritten" file, and copies notes from the old
 524  * commits listed in the file to their rewritten commits.
 525  *
 526  * Returns 0 on success, -1 on failure.
 527  */
 528 static int copy_notes_for_rebase(const struct am_state *state)
 529 {
 530         struct notes_rewrite_cfg *c;
 531         struct strbuf sb = STRBUF_INIT;
 532         const char *invalid_line = _("Malformed input line: '%s'.");
 533         const char *msg = "Notes added by 'git rebase'";
 534         FILE *fp;
 535         int ret = 0;
 536
 537         assert(state->rebasing);
 538
 539         c = init_copy_notes_for_rewrite("rebase");
 540         if (!c)
 541                 return 0;
 542
 543         fp = xfopen(am_path(state, "rewritten"), "r");
 544
 545         while (!strbuf_getline_lf(&sb, fp)) {
 546                 struct object_id from_obj, to_obj;
 547
 548                 if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
 549                         ret = error(invalid_line, sb.buf);
 550                         goto finish;
 551                 }
 552
 553                 if (get_oid_hex(sb.buf, &from_obj)) {
 554                         ret = error(invalid_line, sb.buf);
 555                         goto finish;
 556                 }
 557
 558                 if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
 559                         ret = error(invalid_line, sb.buf);
 560                         goto finish;
 561                 }
 562
 563                 if (get_oid_hex(sb.buf + GIT_SHA1_HEXSZ + 1, &to_obj)) {
 564                         ret = error(invalid_line, sb.buf);
 565                         goto finish;
 566                 }
 567
 568                 if (copy_note_for_rewrite(c, from_obj.hash, to_obj.hash))
 569                         ret = error(_("Failed to copy notes from '%s' to '%s'"),
 570                                         oid_to_hex(&from_obj), oid_to_hex(&to_obj));
 571         }
 572
 573 finish:
 574         finish_copy_notes_for_rewrite(c, msg);
 575         fclose(fp);
 576         strbuf_release(&sb);
 577         return ret;
 578 }
 579
 580 /**
 581  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
 582  * non-indented lines and checking if they look like they begin with valid
 583  * header field names.
 584  *
 585  * Returns 1 if the file looks like a piece of mail, 0 otherwise.
 586  */
 587 static int is_mail(FILE *fp)
 588 {
 589         const char *header_regex = "^[!-9;-~]+:";
 590         struct strbuf sb = STRBUF_INIT;
 591         regex_t regex;
 592         int ret = 1;
 593
 594         if (fseek(fp, 0L, SEEK_SET))
 595                 die_errno(_("fseek failed"));
 596
 597         if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
 598                 die("invalid pattern: %s", header_regex);
 599
 600         while (!strbuf_getline(&sb, fp)) {
 601                 if (!sb.len)
 602                         break; /* End of header */
 603
 604                 /* Ignore indented folded lines */
 605                 if (*sb.buf == '\t' || *sb.buf == ' ')
 606                         continue;
 607
 608                 /* It's a header if it matches header_regex */
 609                 if (regexec(&regex, sb.buf, 0, NULL, 0)) {
 610                         ret = 0;
 611                         goto done;
 612                 }
 613         }
 614
 615 done:
 616         regfree(&regex);
 617         strbuf_release(&sb);
 618         return ret;
 619 }
 620
 621 /**
 622  * Attempts to detect the patch_format of the patches contained in `paths`,
 623  * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
 624  * detection fails.
 625  */
 626 static int detect_patch_format(const char **paths)
 627 {
 628         enum patch_format ret = PATCH_FORMAT_UNKNOWN;
 629         struct strbuf l1 = STRBUF_INIT;
 630         struct strbuf l2 = STRBUF_INIT;
 631         struct strbuf l3 = STRBUF_INIT;
 632         FILE *fp;
 633
 634         /*
 635          * We default to mbox format if input is from stdin and for directories
 636          */
 637         if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
 638                 return PATCH_FORMAT_MBOX;
 639
 640         /*
 641          * Otherwise, check the first few lines of the first patch, starting
 642          * from the first non-blank line, to try to detect its format.
 643          */
 644
 645         fp = xfopen(*paths, "r");
 646
 647         while (!strbuf_getline(&l1, fp)) {
 648                 if (l1.len)
 649                         break;
 650         }
 651
 652         if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
 653                 ret = PATCH_FORMAT_MBOX;
 654                 goto done;
 655         }
 656
 657         if (starts_with(l1.buf, "# This series applies on GIT commit")) {
 658                 ret = PATCH_FORMAT_STGIT_SERIES;
 659                 goto done;
 660         }
 661
 662         if (!strcmp(l1.buf, "# HG changeset patch")) {
 663                 ret = PATCH_FORMAT_HG;
 664                 goto done;
 665         }
 666
 667         strbuf_reset(&l2);
 668         strbuf_getline(&l2, fp);
 669         strbuf_reset(&l3);
 670         strbuf_getline(&l3, fp);
 671
 672         /*
 673          * If the second line is empty and the third is a From, Author or Date
 674          * entry, this is likely an StGit patch.
 675          */
 676         if (l1.len && !l2.len &&
 677                 (starts_with(l3.buf, "From:") ||
 678                  starts_with(l3.buf, "Author:") ||
 679                  starts_with(l3.buf, "Date:"))) {
 680                 ret = PATCH_FORMAT_STGIT;
 681                 goto done;
 682         }
 683
 684         if (l1.len && is_mail(fp)) {
 685                 ret = PATCH_FORMAT_MBOX;
 686                 goto done;
 687         }
 688
 689 done:
 690         fclose(fp);
 691         strbuf_release(&l1);
 692         return ret;
 693 }
 694
 695 /**
 696  * Splits out individual email patches from `paths`, where each path is either
 697  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
 698  */
 699 static int split_mail_mbox(struct am_state *state, const char **paths,
 700                                 int keep_cr, int mboxrd)
 701 {
 702         struct child_process cp = CHILD_PROCESS_INIT;
 703         struct strbuf last = STRBUF_INIT;
 704
 705         cp.git_cmd = 1;
 706         argv_array_push(&cp.args, "mailsplit");
 707         argv_array_pushf(&cp.args, "-d%d", state->prec);
 708         argv_array_pushf(&cp.args, "-o%s", state->dir);
 709         argv_array_push(&cp.args, "-b");
 710         if (keep_cr)
 711                 argv_array_push(&cp.args, "--keep-cr");
 712         if (mboxrd)
 713                 argv_array_push(&cp.args, "--mboxrd");
 714         argv_array_push(&cp.args, "--");
 715         argv_array_pushv(&cp.args, paths);
 716
 717         if (capture_command(&cp, &last, 8))
 718                 return -1;
 719
 720         state->cur = 1;
 721         state->last = strtol(last.buf, NULL, 10);
 722
 723         return 0;
 724 }
 725
 726 /**
 727  * Callback signature for split_mail_conv(). The foreign patch should be
 728  * read from `in`, and the converted patch (in RFC2822 mail format) should be
 729  * written to `out`. Return 0 on success, or -1 on failure.
 730  */
 731 typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
 732
 733 /**
 734  * Calls `fn` for each file in `paths` to convert the foreign patch to the
 735  * RFC2822 mail format suitable for parsing with git-mailinfo.
 736  *
 737  * Returns 0 on success, -1 on failure.
 738  */
 739 static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
 740                         const char **paths, int keep_cr)
 741 {
 742         static const char *stdin_only[] = {"-", NULL};
 743         int i;
 744
 745         if (!*paths)
 746                 paths = stdin_only;
 747
 748         for (i = 0; *paths; paths++, i++) {
 749                 FILE *in, *out;
 750                 const char *mail;
 751                 int ret;
 752
 753                 if (!strcmp(*paths, "-"))
 754                         in = stdin;
 755                 else
 756                         in = fopen(*paths, "r");
 757
 758                 if (!in)
 759                         return error_errno(_("could not open '%s' for reading"),
 760                                            *paths);
 761
 762                 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 763
 764                 out = fopen(mail, "w");
 765                 if (!out)
 766                         return error_errno(_("could not open '%s' for writing"),
 767                                            mail);
 768
 769                 ret = fn(out, in, keep_cr);
 770
 771                 fclose(out);
 772                 fclose(in);
 773
 774                 if (ret)
 775                         return error(_("could not parse patch '%s'"), *paths);
 776         }
 777
 778         state->cur = 1;
 779         state->last = i;
 780         return 0;
 781 }
 782
 783 /**
 784  * A split_mail_conv() callback that converts an StGit patch to an RFC2822
 785  * message suitable for parsing with git-mailinfo.
 786  */
 787 static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 788 {
 789         struct strbuf sb = STRBUF_INIT;
 790         int subject_printed = 0;
 791
 792         while (!strbuf_getline_lf(&sb, in)) {
 793                 const char *str;
 794
 795                 if (str_isspace(sb.buf))
 796                         continue;
 797                 else if (skip_prefix(sb.buf, "Author:", &str))
 798                         fprintf(out, "From:%s\n", str);
 799                 else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
 800                         fprintf(out, "%s\n", sb.buf);
 801                 else if (!subject_printed) {
 802                         fprintf(out, "Subject: %s\n", sb.buf);
 803                         subject_printed = 1;
 804                 } else {
 805                         fprintf(out, "\n%s\n", sb.buf);
 806                         break;
 807                 }
 808         }
 809
 810         strbuf_reset(&sb);
 811         while (strbuf_fread(&sb, 8192, in) > 0) {
 812                 fwrite(sb.buf, 1, sb.len, out);
 813                 strbuf_reset(&sb);
 814         }
 815
 816         strbuf_release(&sb);
 817         return 0;
 818 }
 819
 820 /**
 821  * This function only supports a single StGit series file in `paths`.
 822  *
 823  * Given an StGit series file, converts the StGit patches in the series into
 824  * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
 825  * the state directory.
 826  *
 827  * Returns 0 on success, -1 on failure.
 828  */
 829 static int split_mail_stgit_series(struct am_state *state, const char **paths,
 830                                         int keep_cr)
 831 {
 832         const char *series_dir;
 833         char *series_dir_buf;
 834         FILE *fp;
 835         struct argv_array patches = ARGV_ARRAY_INIT;
 836         struct strbuf sb = STRBUF_INIT;
 837         int ret;
 838
 839         if (!paths[0] || paths[1])
 840                 return error(_("Only one StGIT patch series can be applied at once"));
 841
 842         series_dir_buf = xstrdup(*paths);
 843         series_dir = dirname(series_dir_buf);
 844
 845         fp = fopen(*paths, "r");
 846         if (!fp)
 847                 return error_errno(_("could not open '%s' for reading"), *paths);
 848
 849         while (!strbuf_getline_lf(&sb, fp)) {
 850                 if (*sb.buf == '#')
 851                         continue; /* skip comment lines */
 852
 853                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
 854         }
 855
 856         fclose(fp);
 857         strbuf_release(&sb);
 858         free(series_dir_buf);
 859
 860         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
 861
 862         argv_array_clear(&patches);
 863         return ret;
 864 }
 865
 866 /**
 867  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
 868  * message suitable for parsing with git-mailinfo.
 869  */
 870 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 871 {
 872         struct strbuf sb = STRBUF_INIT;
 873
 874         while (!strbuf_getline_lf(&sb, in)) {
 875                 const char *str;
 876
 877                 if (skip_prefix(sb.buf, "# User ", &str))
 878                         fprintf(out, "From: %s\n", str);
 879                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
 880                         unsigned long timestamp;
 881                         long tz, tz2;
 882                         char *end;
 883
 884                         errno = 0;
 885                         timestamp = strtoul(str, &end, 10);
 886                         if (errno)
 887                                 return error(_("invalid timestamp"));
 888
 889                         if (!skip_prefix(end, " ", &str))
 890                                 return error(_("invalid Date line"));
 891
 892                         errno = 0;
 893                         tz = strtol(str, &end, 10);
 894                         if (errno)
 895                                 return error(_("invalid timezone offset"));
 896
 897                         if (*end)
 898                                 return error(_("invalid Date line"));
 899
 900                         /*
 901                          * mercurial's timezone is in seconds west of UTC,
 902                          * however git's timezone is in hours + minutes east of
 903                          * UTC. Convert it.
 904                          */
 905                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
 906                         if (tz > 0)
 907                                 tz2 = -tz2;
 908
 909                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
 910                 } else if (starts_with(sb.buf, "# ")) {
 911                         continue;
 912                 } else {
 913                         fprintf(out, "\n%s\n", sb.buf);
 914                         break;
 915                 }
 916         }
 917
 918         strbuf_reset(&sb);
 919         while (strbuf_fread(&sb, 8192, in) > 0) {
 920                 fwrite(sb.buf, 1, sb.len, out);
 921                 strbuf_reset(&sb);
 922         }
 923
 924         strbuf_release(&sb);
 925         return 0;
 926 }
 927
 928 /**
 929  * Splits a list of files/directories into individual email patches. Each path
 930  * in `paths` must be a file/directory that is formatted according to
 931  * `patch_format`.
 932  *
 933  * Once split out, the individual email patches will be stored in the state
 934  * directory, with each patch's filename being its index, padded to state->prec
 935  * digits.
 936  *
 937  * state->cur will be set to the index of the first mail, and state->last will
 938  * be set to the index of the last mail.
 939  *
 940  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
 941  * to disable this behavior, -1 to use the default configured setting.
 942  *
 943  * Returns 0 on success, -1 on failure.
 944  */
 945 static int split_mail(struct am_state *state, enum patch_format patch_format,
 946                         const char **paths, int keep_cr)
 947 {
 948         if (keep_cr < 0) {
 949                 keep_cr = 0;
 950                 git_config_get_bool("am.keepcr", &keep_cr);
 951         }
 952
 953         switch (patch_format) {
 954         case PATCH_FORMAT_MBOX:
 955                 return split_mail_mbox(state, paths, keep_cr, 0);
 956         case PATCH_FORMAT_STGIT:
 957                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 958         case PATCH_FORMAT_STGIT_SERIES:
 959                 return split_mail_stgit_series(state, paths, keep_cr);
 960         case PATCH_FORMAT_HG:
 961                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
 962         case PATCH_FORMAT_MBOXRD:
 963                 return split_mail_mbox(state, paths, keep_cr, 1);
 964         default:
 965                 die("BUG: invalid patch_format");
 966         }
 967         return -1;
 968 }
 969
 970 /**
 971  * Setup a new am session for applying patches
 972  */
 973 static void am_setup(struct am_state *state, enum patch_format patch_format,
 974                         const char **paths, int keep_cr)
 975 {
 976         struct object_id curr_head;
 977         const char *str;
 978         struct strbuf sb = STRBUF_INIT;
 979
 980         if (!patch_format)
 981                 patch_format = detect_patch_format(paths);
 982
 983         if (!patch_format) {
 984                 fprintf_ln(stderr, _("Patch format detection failed."));
 985                 exit(128);
 986         }
 987
 988         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 989                 die_errno(_("failed to create directory '%s'"), state->dir);
 990
 991         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
 992                 am_destroy(state);
 993                 die(_("Failed to split patches."));
 994         }
 995
 996         if (state->rebasing)
 997                 state->threeway = 1;
 998
 999         write_state_bool(state, "threeway", state->threeway);
1000         write_state_bool(state, "quiet", state->quiet);
1001         write_state_bool(state, "sign", state->signoff);
1002         write_state_bool(state, "utf8", state->utf8);
1003
1004         switch (state->keep) {
1005         case KEEP_FALSE:
1006                 str = "f";
1007                 break;
1008         case KEEP_TRUE:
1009                 str = "t";
1010                 break;
1011         case KEEP_NON_PATCH:
1012                 str = "b";
1013                 break;
1014         default:
1015                 die("BUG: invalid value for state->keep");
1016         }
1017
1018         write_state_text(state, "keep", str);
1019         write_state_bool(state, "messageid", state->message_id);
1020
1021         switch (state->scissors) {
1022         case SCISSORS_UNSET:
1023                 str = "";
1024                 break;
1025         case SCISSORS_FALSE:
1026                 str = "f";
1027                 break;
1028         case SCISSORS_TRUE:
1029                 str = "t";
1030                 break;
1031         default:
1032                 die("BUG: invalid value for state->scissors");
1033         }
1034         write_state_text(state, "scissors", str);
1035
1036         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1037         write_state_text(state, "apply-opt", sb.buf);
1038
1039         if (state->rebasing)
1040                 write_state_text(state, "rebasing", "");
1041         else
1042                 write_state_text(state, "applying", "");
1043
1044         if (!get_oid("HEAD", &curr_head)) {
1045                 write_state_text(state, "abort-safety", oid_to_hex(&curr_head));
1046                 if (!state->rebasing)
1047                         update_ref_oid("am", "ORIG_HEAD", &curr_head, NULL, 0,
1048                                         UPDATE_REFS_DIE_ON_ERR);
1049         } else {
1050                 write_state_text(state, "abort-safety", "");
1051                 if (!state->rebasing)
1052                         delete_ref("ORIG_HEAD", NULL, 0);
1053         }
1054
1055         /*
1056          * NOTE: Since the "next" and "last" files determine if an am_state
1057          * session is in progress, they should be written last.
1058          */
1059
1060         write_state_count(state, "next", state->cur);
1061         write_state_count(state, "last", state->last);
1062
1063         strbuf_release(&sb);
1064 }
1065
1066 /**
1067  * Increments the patch pointer, and cleans am_state for the application of the
1068  * next patch.
1069  */
1070 static void am_next(struct am_state *state)
1071 {
1072         struct object_id head;
1073
1074         free(state->author_name);
1075         state->author_name = NULL;
1076
1077         free(state->author_email);
1078         state->author_email = NULL;
1079
1080         free(state->author_date);
1081         state->author_date = NULL;
1082
1083         free(state->msg);
1084         state->msg = NULL;
1085         state->msg_len = 0;
1086
1087         unlink(am_path(state, "author-script"));
1088         unlink(am_path(state, "final-commit"));
1089
1090         oidclr(&state->orig_commit);
1091         unlink(am_path(state, "original-commit"));
1092
1093         if (!get_oid("HEAD", &head))
1094                 write_state_text(state, "abort-safety", oid_to_hex(&head));
1095         else
1096                 write_state_text(state, "abort-safety", "");
1097
1098         state->cur++;
1099         write_state_count(state, "next", state->cur);
1100 }
1101
1102 /**
1103  * Returns the filename of the current patch email.
1104  */
1105 static const char *msgnum(const struct am_state *state)
1106 {
1107         static struct strbuf sb = STRBUF_INIT;
1108
1109         strbuf_reset(&sb);
1110         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1111
1112         return sb.buf;
1113 }
1114
1115 /**
1116  * Refresh and write index.
1117  */
1118 static void refresh_and_write_cache(void)
1119 {
1120         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1121
1122         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1123         refresh_cache(REFRESH_QUIET);
1124         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1125                 die(_("unable to write index file"));
1126 }
1127
1128 /**
1129  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1130  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1131  * strbuf is provided, the space-separated list of files that differ will be
1132  * appended to it.
1133  */
1134 static int index_has_changes(struct strbuf *sb)
1135 {
1136         struct object_id head;
1137         int i;
1138
1139         if (!get_sha1_tree("HEAD", head.hash)) {
1140                 struct diff_options opt;
1141
1142                 diff_setup(&opt);
1143                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1144                 if (!sb)
1145                         DIFF_OPT_SET(&opt, QUICK);
1146                 do_diff_cache(head.hash, &opt);
1147                 diffcore_std(&opt);
1148                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1149                         if (i)
1150                                 strbuf_addch(sb, ' ');
1151                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1152                 }
1153                 diff_flush(&opt);
1154                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1155         } else {
1156                 for (i = 0; sb && i < active_nr; i++) {
1157                         if (i)
1158                                 strbuf_addch(sb, ' ');
1159                         strbuf_addstr(sb, active_cache[i]->name);
1160                 }
1161                 return !!active_nr;
1162         }
1163 }
1164
1165 /**
1166  * Dies with a user-friendly message on how to proceed after resolving the
1167  * problem. This message can be overridden with state->resolvemsg.
1168  */
1169 static void NORETURN die_user_resolve(const struct am_state *state)
1170 {
1171         if (state->resolvemsg) {
1172                 printf_ln("%s", state->resolvemsg);
1173         } else {
1174                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1175
1176                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1177                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1178                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1179         }
1180
1181         exit(128);
1182 }
1183
1184 static void am_signoff(struct strbuf *sb)
1185 {
1186         char *cp;
1187         struct strbuf mine = STRBUF_INIT;
1188
1189         /* Does it end with our own sign-off? */
1190         strbuf_addf(&mine, "\n%s%s\n",
1191                     sign_off_header,
1192                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1193                              getenv("GIT_COMMITTER_EMAIL")));
1194         if (mine.len < sb->len &&
1195             !strcmp(mine.buf, sb->buf + sb->len - mine.len))
1196                 goto exit; /* no need to duplicate */
1197
1198         /* Does it have any Signed-off-by: in the text */
1199         for (cp = sb->buf;
1200              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1201              cp = strchr(cp, '\n')) {
1202                 if (sb->buf == cp || cp[-1] == '\n')
1203                         break;
1204         }
1205
1206         strbuf_addstr(sb, mine.buf + !!cp);
1207 exit:
1208         strbuf_release(&mine);
1209 }
1210
1211 /**
1212  * Appends signoff to the "msg" field of the am_state.
1213  */
1214 static void am_append_signoff(struct am_state *state)
1215 {
1216         struct strbuf sb = STRBUF_INIT;
1217
1218         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1219         am_signoff(&sb);
1220         state->msg = strbuf_detach(&sb, &state->msg_len);
1221 }
1222
1223 /**
1224  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1225  * state->msg will be set to the patch message. state->author_name,
1226  * state->author_email and state->author_date will be set to the patch author's
1227  * name, email and date respectively. The patch body will be written to the
1228  * state directory's "patch" file.
1229  *
1230  * Returns 1 if the patch should be skipped, 0 otherwise.
1231  */
1232 static int parse_mail(struct am_state *state, const char *mail)
1233 {
1234         FILE *fp;
1235         struct strbuf sb = STRBUF_INIT;
1236         struct strbuf msg = STRBUF_INIT;
1237         struct strbuf author_name = STRBUF_INIT;
1238         struct strbuf author_date = STRBUF_INIT;
1239         struct strbuf author_email = STRBUF_INIT;
1240         int ret = 0;
1241         struct mailinfo mi;
1242
1243         setup_mailinfo(&mi);
1244
1245         if (state->utf8)
1246                 mi.metainfo_charset = get_commit_output_encoding();
1247         else
1248                 mi.metainfo_charset = NULL;
1249
1250         switch (state->keep) {
1251         case KEEP_FALSE:
1252                 break;
1253         case KEEP_TRUE:
1254                 mi.keep_subject = 1;
1255                 break;
1256         case KEEP_NON_PATCH:
1257                 mi.keep_non_patch_brackets_in_subject = 1;
1258                 break;
1259         default:
1260                 die("BUG: invalid value for state->keep");
1261         }
1262
1263         if (state->message_id)
1264                 mi.add_message_id = 1;
1265
1266         switch (state->scissors) {
1267         case SCISSORS_UNSET:
1268                 break;
1269         case SCISSORS_FALSE:
1270                 mi.use_scissors = 0;
1271                 break;
1272         case SCISSORS_TRUE:
1273                 mi.use_scissors = 1;
1274                 break;
1275         default:
1276                 die("BUG: invalid value for state->scissors");
1277         }
1278
1279         mi.input = fopen(mail, "r");
1280         if (!mi.input)
1281                 die("could not open input");
1282         mi.output = fopen(am_path(state, "info"), "w");
1283         if (!mi.output)
1284                 die("could not open output 'info'");
1285         if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
1286                 die("could not parse patch");
1287
1288         fclose(mi.input);
1289         fclose(mi.output);
1290
1291         /* Extract message and author information */
1292         fp = xfopen(am_path(state, "info"), "r");
1293         while (!strbuf_getline_lf(&sb, fp)) {
1294                 const char *x;
1295
1296                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1297                         if (msg.len)
1298                                 strbuf_addch(&msg, '\n');
1299                         strbuf_addstr(&msg, x);
1300                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1301                         strbuf_addstr(&author_name, x);
1302                 else if (skip_prefix(sb.buf, "Email: ", &x))
1303                         strbuf_addstr(&author_email, x);
1304                 else if (skip_prefix(sb.buf, "Date: ", &x))
1305                         strbuf_addstr(&author_date, x);
1306         }
1307         fclose(fp);
1308
1309         /* Skip pine's internal folder data */
1310         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1311                 ret = 1;
1312                 goto finish;
1313         }
1314
1315         if (is_empty_file(am_path(state, "patch"))) {
1316                 printf_ln(_("Patch is empty. Was it split wrong?"));
1317                 die_user_resolve(state);
1318         }
1319
1320         strbuf_addstr(&msg, "\n\n");
1321         strbuf_addbuf(&msg, &mi.log_message);
1322         strbuf_stripspace(&msg, 0);
1323
1324         if (state->signoff)
1325                 am_signoff(&msg);
1326
1327         assert(!state->author_name);
1328         state->author_name = strbuf_detach(&author_name, NULL);
1329
1330         assert(!state->author_email);
1331         state->author_email = strbuf_detach(&author_email, NULL);
1332
1333         assert(!state->author_date);
1334         state->author_date = strbuf_detach(&author_date, NULL);
1335
1336         assert(!state->msg);
1337         state->msg = strbuf_detach(&msg, &state->msg_len);
1338
1339 finish:
1340         strbuf_release(&msg);
1341         strbuf_release(&author_date);
1342         strbuf_release(&author_email);
1343         strbuf_release(&author_name);
1344         strbuf_release(&sb);
1345         clear_mailinfo(&mi);
1346         return ret;
1347 }
1348
1349 /**
1350  * Sets commit_id to the commit hash where the mail was generated from.
1351  * Returns 0 on success, -1 on failure.
1352  */
1353 static int get_mail_commit_oid(struct object_id *commit_id, const char *mail)
1354 {
1355         struct strbuf sb = STRBUF_INIT;
1356         FILE *fp = xfopen(mail, "r");
1357         const char *x;
1358
1359         if (strbuf_getline_lf(&sb, fp))
1360                 return -1;
1361
1362         if (!skip_prefix(sb.buf, "From ", &x))
1363                 return -1;
1364
1365         if (get_oid_hex(x, commit_id) < 0)
1366                 return -1;
1367
1368         strbuf_release(&sb);
1369         fclose(fp);
1370         return 0;
1371 }
1372
1373 /**
1374  * Sets state->msg, state->author_name, state->author_email, state->author_date
1375  * to the commit's respective info.
1376  */
1377 static void get_commit_info(struct am_state *state, struct commit *commit)
1378 {
1379         const char *buffer, *ident_line, *author_date, *msg;
1380         size_t ident_len;
1381         struct ident_split ident_split;
1382         struct strbuf sb = STRBUF_INIT;
1383
1384         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1385
1386         ident_line = find_commit_header(buffer, "author", &ident_len);
1387
1388         if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
1389                 strbuf_add(&sb, ident_line, ident_len);
1390                 die(_("invalid ident line: %s"), sb.buf);
1391         }
1392
1393         assert(!state->author_name);
1394         if (ident_split.name_begin) {
1395                 strbuf_add(&sb, ident_split.name_begin,
1396                         ident_split.name_end - ident_split.name_begin);
1397                 state->author_name = strbuf_detach(&sb, NULL);
1398         } else
1399                 state->author_name = xstrdup("");
1400
1401         assert(!state->author_email);
1402         if (ident_split.mail_begin) {
1403                 strbuf_add(&sb, ident_split.mail_begin,
1404                         ident_split.mail_end - ident_split.mail_begin);
1405                 state->author_email = strbuf_detach(&sb, NULL);
1406         } else
1407                 state->author_email = xstrdup("");
1408
1409         author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
1410         strbuf_addstr(&sb, author_date);
1411         assert(!state->author_date);
1412         state->author_date = strbuf_detach(&sb, NULL);
1413
1414         assert(!state->msg);
1415         msg = strstr(buffer, "\n\n");
1416         if (!msg)
1417                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1418         state->msg = xstrdup(msg + 2);
1419         state->msg_len = strlen(state->msg);
1420 }
1421
1422 /**
1423  * Writes `commit` as a patch to the state directory's "patch" file.
1424  */
1425 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1426 {
1427         struct rev_info rev_info;
1428         FILE *fp;
1429
1430         fp = xfopen(am_path(state, "patch"), "w");
1431         init_revisions(&rev_info, NULL);
1432         rev_info.diff = 1;
1433         rev_info.abbrev = 0;
1434         rev_info.disable_stdin = 1;
1435         rev_info.show_root_diff = 1;
1436         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1437         rev_info.no_commit_id = 1;
1438         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1439         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1440         rev_info.diffopt.use_color = 0;
1441         rev_info.diffopt.file = fp;
1442         rev_info.diffopt.close_file = 1;
1443         add_pending_object(&rev_info, &commit->object, "");
1444         diff_setup_done(&rev_info.diffopt);
1445         log_tree_commit(&rev_info, commit);
1446 }
1447
1448 /**
1449  * Writes the diff of the index against HEAD as a patch to the state
1450  * directory's "patch" file.
1451  */
1452 static void write_index_patch(const struct am_state *state)
1453 {
1454         struct tree *tree;
1455         struct object_id head;
1456         struct rev_info rev_info;
1457         FILE *fp;
1458
1459         if (!get_sha1_tree("HEAD", head.hash))
1460                 tree = lookup_tree(head.hash);
1461         else
1462                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1463
1464         fp = xfopen(am_path(state, "patch"), "w");
1465         init_revisions(&rev_info, NULL);
1466         rev_info.diff = 1;
1467         rev_info.disable_stdin = 1;
1468         rev_info.no_commit_id = 1;
1469         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1470         rev_info.diffopt.use_color = 0;
1471         rev_info.diffopt.file = fp;
1472         rev_info.diffopt.close_file = 1;
1473         add_pending_object(&rev_info, &tree->object, "");
1474         diff_setup_done(&rev_info.diffopt);
1475         run_diff_index(&rev_info, 1);
1476 }
1477
1478 /**
1479  * Like parse_mail(), but parses the mail by looking up its commit ID
1480  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1481  * of patches.
1482  *
1483  * state->orig_commit will be set to the original commit ID.
1484  *
1485  * Will always return 0 as the patch should never be skipped.
1486  */
1487 static int parse_mail_rebase(struct am_state *state, const char *mail)
1488 {
1489         struct commit *commit;
1490         struct object_id commit_oid;
1491
1492         if (get_mail_commit_oid(&commit_oid, mail) < 0)
1493                 die(_("could not parse %s"), mail);
1494
1495         commit = lookup_commit_or_die(commit_oid.hash, mail);
1496
1497         get_commit_info(state, commit);
1498
1499         write_commit_patch(state, commit);
1500
1501         oidcpy(&state->orig_commit, &commit_oid);
1502         write_state_text(state, "original-commit", oid_to_hex(&commit_oid));
1503
1504         return 0;
1505 }
1506
1507 /**
1508  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1509  * `index_file` is not NULL, the patch will be applied to that index.
1510  */
1511 static int run_apply(const struct am_state *state, const char *index_file)
1512 {
1513         struct argv_array apply_paths = ARGV_ARRAY_INIT;
1514         struct argv_array apply_opts = ARGV_ARRAY_INIT;
1515         struct apply_state apply_state;
1516         int res, opts_left;
1517         static struct lock_file lock_file;
1518         int force_apply = 0;
1519         int options = 0;
1520
1521         if (init_apply_state(&apply_state, NULL, &lock_file))
1522                 die("BUG: init_apply_state() failed");
1523
1524         argv_array_push(&apply_opts, "apply");
1525         argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
1526
1527         opts_left = apply_parse_options(apply_opts.argc, apply_opts.argv,
1528                                         &apply_state, &force_apply, &options,
1529                                         NULL);
1530
1531         if (opts_left != 0)
1532                 die("unknown option passed through to git apply");
1533
1534         if (index_file) {
1535                 apply_state.index_file = index_file;
1536                 apply_state.cached = 1;
1537         } else
1538                 apply_state.check_index = 1;
1539
1540         /*
1541          * If we are allowed to fall back on 3-way merge, don't give false
1542          * errors during the initial attempt.
1543          */
1544         if (state->threeway && !index_file)
1545                 apply_state.apply_verbosity = verbosity_silent;
1546
1547         if (check_apply_state(&apply_state, force_apply))
1548                 die("BUG: check_apply_state() failed");
1549
1550         argv_array_push(&apply_paths, am_path(state, "patch"));
1551
1552         res = apply_all_patches(&apply_state, apply_paths.argc, apply_paths.argv, options);
1553
1554         argv_array_clear(&apply_paths);
1555         argv_array_clear(&apply_opts);
1556         clear_apply_state(&apply_state);
1557
1558         if (res)
1559                 return res;
1560
1561         if (index_file) {
1562                 /* Reload index as apply_all_patches() will have modified it. */
1563                 discard_cache();
1564                 read_cache_from(index_file);
1565         }
1566
1567         return 0;
1568 }
1569
1570 /**
1571  * Builds an index that contains just the blobs needed for a 3way merge.
1572  */
1573 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1574 {
1575         struct child_process cp = CHILD_PROCESS_INIT;
1576
1577         cp.git_cmd = 1;
1578         argv_array_push(&cp.args, "apply");
1579         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1580         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1581         argv_array_push(&cp.args, am_path(state, "patch"));
1582
1583         if (run_command(&cp))
1584                 return -1;
1585
1586         return 0;
1587 }
1588
1589 /**
1590  * Attempt a threeway merge, using index_path as the temporary index.
1591  */
1592 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1593 {
1594         struct object_id orig_tree, their_tree, our_tree;
1595         const struct object_id *bases[1] = { &orig_tree };
1596         struct merge_options o;
1597         struct commit *result;
1598         char *their_tree_name;
1599
1600         if (get_oid("HEAD", &our_tree) < 0)
1601                 hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
1602
1603         if (build_fake_ancestor(state, index_path))
1604                 return error("could not build fake ancestor");
1605
1606         discard_cache();
1607         read_cache_from(index_path);
1608
1609         if (write_index_as_tree(orig_tree.hash, &the_index, index_path, 0, NULL))
1610                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1611
1612         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1613
1614         if (!state->quiet) {
1615                 /*
1616                  * List paths that needed 3-way fallback, so that the user can
1617                  * review them with extra care to spot mismerges.
1618                  */
1619                 struct rev_info rev_info;
1620                 const char *diff_filter_str = "--diff-filter=AM";
1621
1622                 init_revisions(&rev_info, NULL);
1623                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1624                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1625                 add_pending_sha1(&rev_info, "HEAD", our_tree.hash, 0);
1626                 diff_setup_done(&rev_info.diffopt);
1627                 run_diff_index(&rev_info, 1);
1628         }
1629
1630         if (run_apply(state, index_path))
1631                 return error(_("Did you hand edit your patch?\n"
1632                                 "It does not apply to blobs recorded in its index."));
1633
1634         if (write_index_as_tree(their_tree.hash, &the_index, index_path, 0, NULL))
1635                 return error("could not write tree");
1636
1637         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1638
1639         discard_cache();
1640         read_cache();
1641
1642         /*
1643          * This is not so wrong. Depending on which base we picked, orig_tree
1644          * may be wildly different from ours, but their_tree has the same set of
1645          * wildly different changes in parts the patch did not touch, so
1646          * recursive ends up canceling them, saying that we reverted all those
1647          * changes.
1648          */
1649
1650         init_merge_options(&o);
1651
1652         o.branch1 = "HEAD";
1653         their_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
1654         o.branch2 = their_tree_name;
1655
1656         if (state->quiet)
1657                 o.verbosity = 0;
1658
1659         if (merge_recursive_generic(&o, &our_tree, &their_tree, 1, bases, &result)) {
1660                 rerere(state->allow_rerere_autoupdate);
1661                 free(their_tree_name);
1662                 return error(_("Failed to merge in the changes."));
1663         }
1664
1665         free(their_tree_name);
1666         return 0;
1667 }
1668
1669 /**
1670  * Commits the current index with state->msg as the commit message and
1671  * state->author_name, state->author_email and state->author_date as the author
1672  * information.
1673  */
1674 static void do_commit(const struct am_state *state)
1675 {
1676         struct object_id tree, parent, commit;
1677         const struct object_id *old_oid;
1678         struct commit_list *parents = NULL;
1679         const char *reflog_msg, *author;
1680         struct strbuf sb = STRBUF_INIT;
1681
1682         if (run_hook_le(NULL, "pre-applypatch", NULL))
1683                 exit(1);
1684
1685         if (write_cache_as_tree(tree.hash, 0, NULL))
1686                 die(_("git write-tree failed to write a tree"));
1687
1688         if (!get_sha1_commit("HEAD", parent.hash)) {
1689                 old_oid = &parent;
1690                 commit_list_insert(lookup_commit(parent.hash), &parents);
1691         } else {
1692                 old_oid = NULL;
1693                 say(state, stderr, _("applying to an empty history"));
1694         }
1695
1696         author = fmt_ident(state->author_name, state->author_email,
1697                         state->ignore_date ? NULL : state->author_date,
1698                         IDENT_STRICT);
1699
1700         if (state->committer_date_is_author_date)
1701                 setenv("GIT_COMMITTER_DATE",
1702                         state->ignore_date ? "" : state->author_date, 1);
1703
1704         if (commit_tree(state->msg, state->msg_len, tree.hash, parents, commit.hash,
1705                                 author, state->sign_commit))
1706                 die(_("failed to write commit object"));
1707
1708         reflog_msg = getenv("GIT_REFLOG_ACTION");
1709         if (!reflog_msg)
1710                 reflog_msg = "am";
1711
1712         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1713                         state->msg);
1714
1715         update_ref_oid(sb.buf, "HEAD", &commit, old_oid, 0,
1716                         UPDATE_REFS_DIE_ON_ERR);
1717
1718         if (state->rebasing) {
1719                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1720
1721                 assert(!is_null_oid(&state->orig_commit));
1722                 fprintf(fp, "%s ", oid_to_hex(&state->orig_commit));
1723                 fprintf(fp, "%s\n", oid_to_hex(&commit));
1724                 fclose(fp);
1725         }
1726
1727         run_hook_le(NULL, "post-applypatch", NULL);
1728
1729         strbuf_release(&sb);
1730 }
1731
1732 /**
1733  * Validates the am_state for resuming -- the "msg" and authorship fields must
1734  * be filled up.
1735  */
1736 static void validate_resume_state(const struct am_state *state)
1737 {
1738         if (!state->msg)
1739                 die(_("cannot resume: %s does not exist."),
1740                         am_path(state, "final-commit"));
1741
1742         if (!state->author_name || !state->author_email || !state->author_date)
1743                 die(_("cannot resume: %s does not exist."),
1744                         am_path(state, "author-script"));
1745 }
1746
1747 /**
1748  * Interactively prompt the user on whether the current patch should be
1749  * applied.
1750  *
1751  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1752  * skip it.
1753  */
1754 static int do_interactive(struct am_state *state)
1755 {
1756         assert(state->msg);
1757
1758         if (!isatty(0))
1759                 die(_("cannot be interactive without stdin connected to a terminal."));
1760
1761         for (;;) {
1762                 const char *reply;
1763
1764                 puts(_("Commit Body is:"));
1765                 puts("--------------------------");
1766                 printf("%s", state->msg);
1767                 puts("--------------------------");
1768
1769                 /*
1770                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1771                  * in your translation. The program will only accept English
1772                  * input at this point.
1773                  */
1774                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1775
1776                 if (!reply) {
1777                         continue;
1778                 } else if (*reply == 'y' || *reply == 'Y') {
1779                         return 0;
1780                 } else if (*reply == 'a' || *reply == 'A') {
1781                         state->interactive = 0;
1782                         return 0;
1783                 } else if (*reply == 'n' || *reply == 'N') {
1784                         return 1;
1785                 } else if (*reply == 'e' || *reply == 'E') {
1786                         struct strbuf msg = STRBUF_INIT;
1787
1788                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1789                                 free(state->msg);
1790                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1791                         }
1792                         strbuf_release(&msg);
1793                 } else if (*reply == 'v' || *reply == 'V') {
1794                         const char *pager = git_pager(1);
1795                         struct child_process cp = CHILD_PROCESS_INIT;
1796
1797                         if (!pager)
1798                                 pager = "cat";
1799                         prepare_pager_args(&cp, pager);
1800                         argv_array_push(&cp.args, am_path(state, "patch"));
1801                         run_command(&cp);
1802                 }
1803         }
1804 }
1805
1806 /**
1807  * Applies all queued mail.
1808  *
1809  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1810  * well as the state directory's "patch" file is used as-is for applying the
1811  * patch and committing it.
1812  */
1813 static void am_run(struct am_state *state, int resume)
1814 {
1815         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1816         struct strbuf sb = STRBUF_INIT;
1817
1818         unlink(am_path(state, "dirtyindex"));
1819
1820         refresh_and_write_cache();
1821
1822         if (index_has_changes(&sb)) {
1823                 write_state_bool(state, "dirtyindex", 1);
1824                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1825         }
1826
1827         strbuf_release(&sb);
1828
1829         while (state->cur <= state->last) {
1830                 const char *mail = am_path(state, msgnum(state));
1831                 int apply_status;
1832
1833                 reset_ident_date();
1834
1835                 if (!file_exists(mail))
1836                         goto next;
1837
1838                 if (resume) {
1839                         validate_resume_state(state);
1840                 } else {
1841                         int skip;
1842
1843                         if (state->rebasing)
1844                                 skip = parse_mail_rebase(state, mail);
1845                         else
1846                                 skip = parse_mail(state, mail);
1847
1848                         if (skip)
1849                                 goto next; /* mail should be skipped */
1850
1851                         write_author_script(state);
1852                         write_commit_msg(state);
1853                 }
1854
1855                 if (state->interactive && do_interactive(state))
1856                         goto next;
1857
1858                 if (run_applypatch_msg_hook(state))
1859                         exit(1);
1860
1861                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1862
1863                 apply_status = run_apply(state, NULL);
1864
1865                 if (apply_status && state->threeway) {
1866                         struct strbuf sb = STRBUF_INIT;
1867
1868                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1869                         apply_status = fall_back_threeway(state, sb.buf);
1870                         strbuf_release(&sb);
1871
1872                         /*
1873                          * Applying the patch to an earlier tree and merging
1874                          * the result may have produced the same tree as ours.
1875                          */
1876                         if (!apply_status && !index_has_changes(NULL)) {
1877                                 say(state, stdout, _("No changes -- Patch already applied."));
1878                                 goto next;
1879                         }
1880                 }
1881
1882                 if (apply_status) {
1883                         int advice_amworkdir = 1;
1884
1885                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1886                                 linelen(state->msg), state->msg);
1887
1888                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1889
1890                         if (advice_amworkdir)
1891                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1892                                                 am_path(state, "patch"));
1893
1894                         die_user_resolve(state);
1895                 }
1896
1897                 do_commit(state);
1898
1899 next:
1900                 am_next(state);
1901
1902                 if (resume)
1903                         am_load(state);
1904                 resume = 0;
1905         }
1906
1907         if (!is_empty_file(am_path(state, "rewritten"))) {
1908                 assert(state->rebasing);
1909                 copy_notes_for_rebase(state);
1910                 run_post_rewrite_hook(state);
1911         }
1912
1913         /*
1914          * In rebasing mode, it's up to the caller to take care of
1915          * housekeeping.
1916          */
1917         if (!state->rebasing) {
1918                 am_destroy(state);
1919                 close_all_packs();
1920                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1921         }
1922 }
1923
1924 /**
1925  * Resume the current am session after patch application failure. The user did
1926  * all the hard work, and we do not have to do any patch application. Just
1927  * trust and commit what the user has in the index and working tree.
1928  */
1929 static void am_resolve(struct am_state *state)
1930 {
1931         validate_resume_state(state);
1932
1933         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1934
1935         if (!index_has_changes(NULL)) {
1936                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1937                         "If there is nothing left to stage, chances are that something else\n"
1938                         "already introduced the same changes; you might want to skip this patch."));
1939                 die_user_resolve(state);
1940         }
1941
1942         if (unmerged_cache()) {
1943                 printf_ln(_("You still have unmerged paths in your index.\n"
1944                         "Did you forget to use 'git add'?"));
1945                 die_user_resolve(state);
1946         }
1947
1948         if (state->interactive) {
1949                 write_index_patch(state);
1950                 if (do_interactive(state))
1951                         goto next;
1952         }
1953
1954         rerere(0);
1955
1956         do_commit(state);
1957
1958 next:
1959         am_next(state);
1960         am_load(state);
1961         am_run(state, 0);
1962 }
1963
1964 /**
1965  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1966  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1967  * failure.
1968  */
1969 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1970 {
1971         struct lock_file *lock_file;
1972         struct unpack_trees_options opts;
1973         struct tree_desc t[2];
1974
1975         if (parse_tree(head) || parse_tree(remote))
1976                 return -1;
1977
1978         lock_file = xcalloc(1, sizeof(struct lock_file));
1979         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1980
1981         refresh_cache(REFRESH_QUIET);
1982
1983         memset(&opts, 0, sizeof(opts));
1984         opts.head_idx = 1;
1985         opts.src_index = &the_index;
1986         opts.dst_index = &the_index;
1987         opts.update = 1;
1988         opts.merge = 1;
1989         opts.reset = reset;
1990         opts.fn = twoway_merge;
1991         init_tree_desc(&t[0], head->buffer, head->size);
1992         init_tree_desc(&t[1], remote->buffer, remote->size);
1993
1994         if (unpack_trees(2, t, &opts)) {
1995                 rollback_lock_file(lock_file);
1996                 return -1;
1997         }
1998
1999         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2000                 die(_("unable to write new index file"));
2001
2002         return 0;
2003 }
2004
2005 /**
2006  * Merges a tree into the index. The index's stat info will take precedence
2007  * over the merged tree's. Returns 0 on success, -1 on failure.
2008  */
2009 static int merge_tree(struct tree *tree)
2010 {
2011         struct lock_file *lock_file;
2012         struct unpack_trees_options opts;
2013         struct tree_desc t[1];
2014
2015         if (parse_tree(tree))
2016                 return -1;
2017
2018         lock_file = xcalloc(1, sizeof(struct lock_file));
2019         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
2020
2021         memset(&opts, 0, sizeof(opts));
2022         opts.head_idx = 1;
2023         opts.src_index = &the_index;
2024         opts.dst_index = &the_index;
2025         opts.merge = 1;
2026         opts.fn = oneway_merge;
2027         init_tree_desc(&t[0], tree->buffer, tree->size);
2028
2029         if (unpack_trees(1, t, &opts)) {
2030                 rollback_lock_file(lock_file);
2031                 return -1;
2032         }
2033
2034         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2035                 die(_("unable to write new index file"));
2036
2037         return 0;
2038 }
2039
2040 /**
2041  * Clean the index without touching entries that are not modified between
2042  * `head` and `remote`.
2043  */
2044 static int clean_index(const struct object_id *head, const struct object_id *remote)
2045 {
2046         struct tree *head_tree, *remote_tree, *index_tree;
2047         struct object_id index;
2048
2049         head_tree = parse_tree_indirect(head->hash);
2050         if (!head_tree)
2051                 return error(_("Could not parse object '%s'."), oid_to_hex(head));
2052
2053         remote_tree = parse_tree_indirect(remote->hash);
2054         if (!remote_tree)
2055                 return error(_("Could not parse object '%s'."), oid_to_hex(remote));
2056
2057         read_cache_unmerged();
2058
2059         if (fast_forward_to(head_tree, head_tree, 1))
2060                 return -1;
2061
2062         if (write_cache_as_tree(index.hash, 0, NULL))
2063                 return -1;
2064
2065         index_tree = parse_tree_indirect(index.hash);
2066         if (!index_tree)
2067                 return error(_("Could not parse object '%s'."), oid_to_hex(&index));
2068
2069         if (fast_forward_to(index_tree, remote_tree, 0))
2070                 return -1;
2071
2072         if (merge_tree(remote_tree))
2073                 return -1;
2074
2075         remove_branch_state();
2076
2077         return 0;
2078 }
2079
2080 /**
2081  * Resets rerere's merge resolution metadata.
2082  */
2083 static void am_rerere_clear(void)
2084 {
2085         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2086         rerere_clear(&merge_rr);
2087         string_list_clear(&merge_rr, 1);
2088 }
2089
2090 /**
2091  * Resume the current am session by skipping the current patch.
2092  */
2093 static void am_skip(struct am_state *state)
2094 {
2095         struct object_id head;
2096
2097         am_rerere_clear();
2098
2099         if (get_oid("HEAD", &head))
2100                 hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
2101
2102         if (clean_index(&head, &head))
2103                 die(_("failed to clean index"));
2104
2105         am_next(state);
2106         am_load(state);
2107         am_run(state, 0);
2108 }
2109
2110 /**
2111  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2112  *
2113  * It is not safe to reset HEAD when:
2114  * 1. git-am previously failed because the index was dirty.
2115  * 2. HEAD has moved since git-am previously failed.
2116  */
2117 static int safe_to_abort(const struct am_state *state)
2118 {
2119         struct strbuf sb = STRBUF_INIT;
2120         struct object_id abort_safety, head;
2121
2122         if (file_exists(am_path(state, "dirtyindex")))
2123                 return 0;
2124
2125         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2126                 if (get_oid_hex(sb.buf, &abort_safety))
2127                         die(_("could not parse %s"), am_path(state, "abort-safety"));
2128         } else
2129                 oidclr(&abort_safety);
2130
2131         if (get_oid("HEAD", &head))
2132                 oidclr(&head);
2133
2134         if (!oidcmp(&head, &abort_safety))
2135                 return 1;
2136
2137         warning(_("You seem to have moved HEAD since the last 'am' failure.\n"
2138                 "Not rewinding to ORIG_HEAD"));
2139
2140         return 0;
2141 }
2142
2143 /**
2144  * Aborts the current am session if it is safe to do so.
2145  */
2146 static void am_abort(struct am_state *state)
2147 {
2148         struct object_id curr_head, orig_head;
2149         int has_curr_head, has_orig_head;
2150         char *curr_branch;
2151
2152         if (!safe_to_abort(state)) {
2153                 am_destroy(state);
2154                 return;
2155         }
2156
2157         am_rerere_clear();
2158
2159         curr_branch = resolve_refdup("HEAD", 0, curr_head.hash, NULL);
2160         has_curr_head = !is_null_oid(&curr_head);
2161         if (!has_curr_head)
2162                 hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
2163
2164         has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
2165         if (!has_orig_head)
2166                 hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
2167
2168         clean_index(&curr_head, &orig_head);
2169
2170         if (has_orig_head)
2171                 update_ref_oid("am --abort", "HEAD", &orig_head,
2172                                 has_curr_head ? &curr_head : NULL, 0,
2173                                 UPDATE_REFS_DIE_ON_ERR);
2174         else if (curr_branch)
2175                 delete_ref(curr_branch, NULL, REF_NODEREF);
2176
2177         free(curr_branch);
2178         am_destroy(state);
2179 }
2180
2181 /**
2182  * parse_options() callback that validates and sets opt->value to the
2183  * PATCH_FORMAT_* enum value corresponding to `arg`.
2184  */
2185 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2186 {
2187         int *opt_value = opt->value;
2188
2189         if (!strcmp(arg, "mbox"))
2190                 *opt_value = PATCH_FORMAT_MBOX;
2191         else if (!strcmp(arg, "stgit"))
2192                 *opt_value = PATCH_FORMAT_STGIT;
2193         else if (!strcmp(arg, "stgit-series"))
2194                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2195         else if (!strcmp(arg, "hg"))
2196                 *opt_value = PATCH_FORMAT_HG;
2197         else if (!strcmp(arg, "mboxrd"))
2198                 *opt_value = PATCH_FORMAT_MBOXRD;
2199         else
2200                 return error(_("Invalid value for --patch-format: %s"), arg);
2201         return 0;
2202 }
2203
2204 enum resume_mode {
2205         RESUME_FALSE = 0,
2206         RESUME_APPLY,
2207         RESUME_RESOLVED,
2208         RESUME_SKIP,
2209         RESUME_ABORT
2210 };
2211
2212 static int git_am_config(const char *k, const char *v, void *cb)
2213 {
2214         int status;
2215
2216         status = git_gpg_config(k, v, NULL);
2217         if (status)
2218                 return status;
2219
2220         return git_default_config(k, v, NULL);
2221 }
2222
2223 int cmd_am(int argc, const char **argv, const char *prefix)
2224 {
2225         struct am_state state;
2226         int binary = -1;
2227         int keep_cr = -1;
2228         int patch_format = PATCH_FORMAT_UNKNOWN;
2229         enum resume_mode resume = RESUME_FALSE;
2230         int in_progress;
2231
2232         const char * const usage[] = {
2233                 N_("git am [<options>] [(<mbox> | <Maildir>)...]"),
2234                 N_("git am [<options>] (--continue | --skip | --abort)"),
2235                 NULL
2236         };
2237
2238         struct option options[] = {
2239                 OPT_BOOL('i', "interactive", &state.interactive,
2240                         N_("run interactively")),
2241                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2242                         N_("historical option -- no-op")),
2243                 OPT_BOOL('3', "3way", &state.threeway,
2244                         N_("allow fall back on 3way merging if needed")),
2245                 OPT__QUIET(&state.quiet, N_("be quiet")),
2246                 OPT_SET_INT('s', "signoff", &state.signoff,
2247                         N_("add a Signed-off-by line to the commit message"),
2248                         SIGNOFF_EXPLICIT),
2249                 OPT_BOOL('u', "utf8", &state.utf8,
2250                         N_("recode into utf8 (default)")),
2251                 OPT_SET_INT('k', "keep", &state.keep,
2252                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2253                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2254                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2255                 OPT_BOOL('m', "message-id", &state.message_id,
2256                         N_("pass -m flag to git-mailinfo")),
2257                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2258                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2259                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2260                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2261                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2262                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2263                 OPT_BOOL('c', "scissors", &state.scissors,
2264                         N_("strip everything before a scissors line")),
2265                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2266                         N_("pass it through git-apply"),
2267                         0),
2268                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2269                         N_("pass it through git-apply"),
2270                         PARSE_OPT_NOARG),
2271                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2272                         N_("pass it through git-apply"),
2273                         PARSE_OPT_NOARG),
2274                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2275                         N_("pass it through git-apply"),
2276                         0),
2277                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2278                         N_("pass it through git-apply"),
2279                         0),
2280                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2281                         N_("pass it through git-apply"),
2282                         0),
2283                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2284                         N_("pass it through git-apply"),
2285                         0),
2286                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2287                         N_("pass it through git-apply"),
2288                         0),
2289                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2290                         N_("format the patch(es) are in"),
2291                         parse_opt_patchformat),
2292                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2293                         N_("pass it through git-apply"),
2294                         PARSE_OPT_NOARG),
2295                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2296                         N_("override error message when patch failure occurs")),
2297                 OPT_CMDMODE(0, "continue", &resume,
2298                         N_("continue applying patches after resolving a conflict"),
2299                         RESUME_RESOLVED),
2300                 OPT_CMDMODE('r', "resolved", &resume,
2301                         N_("synonyms for --continue"),
2302                         RESUME_RESOLVED),
2303                 OPT_CMDMODE(0, "skip", &resume,
2304                         N_("skip the current patch"),
2305                         RESUME_SKIP),
2306                 OPT_CMDMODE(0, "abort", &resume,
2307                         N_("restore the original branch and abort the patching operation."),
2308                         RESUME_ABORT),
2309                 OPT_BOOL(0, "committer-date-is-author-date",
2310                         &state.committer_date_is_author_date,
2311                         N_("lie about committer date")),
2312                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2313                         N_("use current timestamp for author date")),
2314                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2315                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2316                   N_("GPG-sign commits"),
2317                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2318                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2319                         N_("(internal use for git-rebase)")),
2320                 OPT_END()
2321         };
2322
2323         git_config(git_am_config, NULL);
2324
2325         am_state_init(&state, git_path("rebase-apply"));
2326
2327         in_progress = am_in_progress(&state);
2328         if (in_progress)
2329                 am_load(&state);
2330
2331         argc = parse_options(argc, argv, prefix, options, usage, 0);
2332
2333         if (binary >= 0)
2334                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2335                                 "it will be removed. Please do not use it anymore."));
2336
2337         /* Ensure a valid committer ident can be constructed */
2338         git_committer_info(IDENT_STRICT);
2339
2340         if (read_index_preload(&the_index, NULL) < 0)
2341                 die(_("failed to read the index"));
2342
2343         if (in_progress) {
2344                 /*
2345                  * Catch user error to feed us patches when there is a session
2346                  * in progress:
2347                  *
2348                  * 1. mbox path(s) are provided on the command-line.
2349                  * 2. stdin is not a tty: the user is trying to feed us a patch
2350                  *    from standard input. This is somewhat unreliable -- stdin
2351                  *    could be /dev/null for example and the caller did not
2352                  *    intend to feed us a patch but wanted to continue
2353                  *    unattended.
2354                  */
2355                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2356                         die(_("previous rebase directory %s still exists but mbox given."),
2357                                 state.dir);
2358
2359                 if (resume == RESUME_FALSE)
2360                         resume = RESUME_APPLY;
2361
2362                 if (state.signoff == SIGNOFF_EXPLICIT)
2363                         am_append_signoff(&state);
2364         } else {
2365                 struct argv_array paths = ARGV_ARRAY_INIT;
2366                 int i;
2367
2368                 /*
2369                  * Handle stray state directory in the independent-run case. In
2370                  * the --rebasing case, it is up to the caller to take care of
2371                  * stray directories.
2372                  */
2373                 if (file_exists(state.dir) && !state.rebasing) {
2374                         if (resume == RESUME_ABORT) {
2375                                 am_destroy(&state);
2376                                 am_state_release(&state);
2377                                 return 0;
2378                         }
2379
2380                         die(_("Stray %s directory found.\n"
2381                                 "Use \"git am --abort\" to remove it."),
2382                                 state.dir);
2383                 }
2384
2385                 if (resume)
2386                         die(_("Resolve operation not in progress, we are not resuming."));
2387
2388                 for (i = 0; i < argc; i++) {
2389                         if (is_absolute_path(argv[i]) || !prefix)
2390                                 argv_array_push(&paths, argv[i]);
2391                         else
2392                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2393                 }
2394
2395                 am_setup(&state, patch_format, paths.argv, keep_cr);
2396
2397                 argv_array_clear(&paths);
2398         }
2399
2400         switch (resume) {
2401         case RESUME_FALSE:
2402                 am_run(&state, 0);
2403                 break;
2404         case RESUME_APPLY:
2405                 am_run(&state, 1);
2406                 break;
2407         case RESUME_RESOLVED:
2408                 am_resolve(&state);
2409                 break;
2410         case RESUME_SKIP:
2411                 am_skip(&state);
2412                 break;
2413         case RESUME_ABORT:
2414                 am_abort(&state);
2415                 break;
2416         default:
2417                 die("BUG: invalid resume value");
2418         }
2419
2420         am_state_release(&state);
2421
2422         return 0;
2423 }