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(NULL, "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 /**
1185  * Appends signoff to the "msg" field of the am_state.
1186  */
1187 static void am_append_signoff(struct am_state *state)
1188 {
1189         char *cp;
1190         struct strbuf mine = STRBUF_INIT;
1191         struct strbuf sb = STRBUF_INIT;
1192
1193         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1194
1195         /* our sign-off */
1196         strbuf_addf(&mine, "\n%s%s\n",
1197                     sign_off_header,
1198                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1199                              getenv("GIT_COMMITTER_EMAIL")));
1200
1201         /* Does sb end with it already? */
1202         if (mine.len < sb.len &&
1203             !strcmp(mine.buf, sb.buf + sb.len - mine.len))
1204                 goto exit; /* no need to duplicate */
1205
1206         /* Does it have any Signed-off-by: in the text */
1207         for (cp = sb.buf;
1208              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1209              cp = strchr(cp, '\n')) {
1210                 if (sb.buf == cp || cp[-1] == '\n')
1211                         break;
1212         }
1213
1214         strbuf_addstr(&sb, mine.buf + !!cp);
1215 exit:
1216         strbuf_release(&mine);
1217         state->msg = strbuf_detach(&sb, &state->msg_len);
1218 }
1219
1220 /**
1221  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1222  * state->msg will be set to the patch message. state->author_name,
1223  * state->author_email and state->author_date will be set to the patch author's
1224  * name, email and date respectively. The patch body will be written to the
1225  * state directory's "patch" file.
1226  *
1227  * Returns 1 if the patch should be skipped, 0 otherwise.
1228  */
1229 static int parse_mail(struct am_state *state, const char *mail)
1230 {
1231         FILE *fp;
1232         struct strbuf sb = STRBUF_INIT;
1233         struct strbuf msg = STRBUF_INIT;
1234         struct strbuf author_name = STRBUF_INIT;
1235         struct strbuf author_date = STRBUF_INIT;
1236         struct strbuf author_email = STRBUF_INIT;
1237         int ret = 0;
1238         struct mailinfo mi;
1239
1240         setup_mailinfo(&mi);
1241
1242         if (state->utf8)
1243                 mi.metainfo_charset = get_commit_output_encoding();
1244         else
1245                 mi.metainfo_charset = NULL;
1246
1247         switch (state->keep) {
1248         case KEEP_FALSE:
1249                 break;
1250         case KEEP_TRUE:
1251                 mi.keep_subject = 1;
1252                 break;
1253         case KEEP_NON_PATCH:
1254                 mi.keep_non_patch_brackets_in_subject = 1;
1255                 break;
1256         default:
1257                 die("BUG: invalid value for state->keep");
1258         }
1259
1260         if (state->message_id)
1261                 mi.add_message_id = 1;
1262
1263         switch (state->scissors) {
1264         case SCISSORS_UNSET:
1265                 break;
1266         case SCISSORS_FALSE:
1267                 mi.use_scissors = 0;
1268                 break;
1269         case SCISSORS_TRUE:
1270                 mi.use_scissors = 1;
1271                 break;
1272         default:
1273                 die("BUG: invalid value for state->scissors");
1274         }
1275
1276         mi.input = fopen(mail, "r");
1277         if (!mi.input)
1278                 die("could not open input");
1279         mi.output = fopen(am_path(state, "info"), "w");
1280         if (!mi.output)
1281                 die("could not open output 'info'");
1282         if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
1283                 die("could not parse patch");
1284
1285         fclose(mi.input);
1286         fclose(mi.output);
1287
1288         /* Extract message and author information */
1289         fp = xfopen(am_path(state, "info"), "r");
1290         while (!strbuf_getline_lf(&sb, fp)) {
1291                 const char *x;
1292
1293                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1294                         if (msg.len)
1295                                 strbuf_addch(&msg, '\n');
1296                         strbuf_addstr(&msg, x);
1297                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1298                         strbuf_addstr(&author_name, x);
1299                 else if (skip_prefix(sb.buf, "Email: ", &x))
1300                         strbuf_addstr(&author_email, x);
1301                 else if (skip_prefix(sb.buf, "Date: ", &x))
1302                         strbuf_addstr(&author_date, x);
1303         }
1304         fclose(fp);
1305
1306         /* Skip pine's internal folder data */
1307         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1308                 ret = 1;
1309                 goto finish;
1310         }
1311
1312         if (is_empty_file(am_path(state, "patch"))) {
1313                 printf_ln(_("Patch is empty. Was it split wrong?"));
1314                 die_user_resolve(state);
1315         }
1316
1317         strbuf_addstr(&msg, "\n\n");
1318         strbuf_addbuf(&msg, &mi.log_message);
1319         strbuf_stripspace(&msg, 0);
1320
1321         assert(!state->author_name);
1322         state->author_name = strbuf_detach(&author_name, NULL);
1323
1324         assert(!state->author_email);
1325         state->author_email = strbuf_detach(&author_email, NULL);
1326
1327         assert(!state->author_date);
1328         state->author_date = strbuf_detach(&author_date, NULL);
1329
1330         assert(!state->msg);
1331         state->msg = strbuf_detach(&msg, &state->msg_len);
1332
1333 finish:
1334         strbuf_release(&msg);
1335         strbuf_release(&author_date);
1336         strbuf_release(&author_email);
1337         strbuf_release(&author_name);
1338         strbuf_release(&sb);
1339         clear_mailinfo(&mi);
1340         return ret;
1341 }
1342
1343 /**
1344  * Sets commit_id to the commit hash where the mail was generated from.
1345  * Returns 0 on success, -1 on failure.
1346  */
1347 static int get_mail_commit_oid(struct object_id *commit_id, const char *mail)
1348 {
1349         struct strbuf sb = STRBUF_INIT;
1350         FILE *fp = xfopen(mail, "r");
1351         const char *x;
1352
1353         if (strbuf_getline_lf(&sb, fp))
1354                 return -1;
1355
1356         if (!skip_prefix(sb.buf, "From ", &x))
1357                 return -1;
1358
1359         if (get_oid_hex(x, commit_id) < 0)
1360                 return -1;
1361
1362         strbuf_release(&sb);
1363         fclose(fp);
1364         return 0;
1365 }
1366
1367 /**
1368  * Sets state->msg, state->author_name, state->author_email, state->author_date
1369  * to the commit's respective info.
1370  */
1371 static void get_commit_info(struct am_state *state, struct commit *commit)
1372 {
1373         const char *buffer, *ident_line, *author_date, *msg;
1374         size_t ident_len;
1375         struct ident_split ident_split;
1376         struct strbuf sb = STRBUF_INIT;
1377
1378         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1379
1380         ident_line = find_commit_header(buffer, "author", &ident_len);
1381
1382         if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
1383                 strbuf_add(&sb, ident_line, ident_len);
1384                 die(_("invalid ident line: %s"), sb.buf);
1385         }
1386
1387         assert(!state->author_name);
1388         if (ident_split.name_begin) {
1389                 strbuf_add(&sb, ident_split.name_begin,
1390                         ident_split.name_end - ident_split.name_begin);
1391                 state->author_name = strbuf_detach(&sb, NULL);
1392         } else
1393                 state->author_name = xstrdup("");
1394
1395         assert(!state->author_email);
1396         if (ident_split.mail_begin) {
1397                 strbuf_add(&sb, ident_split.mail_begin,
1398                         ident_split.mail_end - ident_split.mail_begin);
1399                 state->author_email = strbuf_detach(&sb, NULL);
1400         } else
1401                 state->author_email = xstrdup("");
1402
1403         author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
1404         strbuf_addstr(&sb, author_date);
1405         assert(!state->author_date);
1406         state->author_date = strbuf_detach(&sb, NULL);
1407
1408         assert(!state->msg);
1409         msg = strstr(buffer, "\n\n");
1410         if (!msg)
1411                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1412         state->msg = xstrdup(msg + 2);
1413         state->msg_len = strlen(state->msg);
1414 }
1415
1416 /**
1417  * Writes `commit` as a patch to the state directory's "patch" file.
1418  */
1419 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1420 {
1421         struct rev_info rev_info;
1422         FILE *fp;
1423
1424         fp = xfopen(am_path(state, "patch"), "w");
1425         init_revisions(&rev_info, NULL);
1426         rev_info.diff = 1;
1427         rev_info.abbrev = 0;
1428         rev_info.disable_stdin = 1;
1429         rev_info.show_root_diff = 1;
1430         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1431         rev_info.no_commit_id = 1;
1432         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1433         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
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, &commit->object, "");
1438         diff_setup_done(&rev_info.diffopt);
1439         log_tree_commit(&rev_info, commit);
1440 }
1441
1442 /**
1443  * Writes the diff of the index against HEAD as a patch to the state
1444  * directory's "patch" file.
1445  */
1446 static void write_index_patch(const struct am_state *state)
1447 {
1448         struct tree *tree;
1449         struct object_id head;
1450         struct rev_info rev_info;
1451         FILE *fp;
1452
1453         if (!get_sha1_tree("HEAD", head.hash))
1454                 tree = lookup_tree(head.hash);
1455         else
1456                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1457
1458         fp = xfopen(am_path(state, "patch"), "w");
1459         init_revisions(&rev_info, NULL);
1460         rev_info.diff = 1;
1461         rev_info.disable_stdin = 1;
1462         rev_info.no_commit_id = 1;
1463         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1464         rev_info.diffopt.use_color = 0;
1465         rev_info.diffopt.file = fp;
1466         rev_info.diffopt.close_file = 1;
1467         add_pending_object(&rev_info, &tree->object, "");
1468         diff_setup_done(&rev_info.diffopt);
1469         run_diff_index(&rev_info, 1);
1470 }
1471
1472 /**
1473  * Like parse_mail(), but parses the mail by looking up its commit ID
1474  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1475  * of patches.
1476  *
1477  * state->orig_commit will be set to the original commit ID.
1478  *
1479  * Will always return 0 as the patch should never be skipped.
1480  */
1481 static int parse_mail_rebase(struct am_state *state, const char *mail)
1482 {
1483         struct commit *commit;
1484         struct object_id commit_oid;
1485
1486         if (get_mail_commit_oid(&commit_oid, mail) < 0)
1487                 die(_("could not parse %s"), mail);
1488
1489         commit = lookup_commit_or_die(commit_oid.hash, mail);
1490
1491         get_commit_info(state, commit);
1492
1493         write_commit_patch(state, commit);
1494
1495         oidcpy(&state->orig_commit, &commit_oid);
1496         write_state_text(state, "original-commit", oid_to_hex(&commit_oid));
1497
1498         return 0;
1499 }
1500
1501 /**
1502  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1503  * `index_file` is not NULL, the patch will be applied to that index.
1504  */
1505 static int run_apply(const struct am_state *state, const char *index_file)
1506 {
1507         struct argv_array apply_paths = ARGV_ARRAY_INIT;
1508         struct argv_array apply_opts = ARGV_ARRAY_INIT;
1509         struct apply_state apply_state;
1510         int res, opts_left;
1511         static struct lock_file lock_file;
1512         int force_apply = 0;
1513         int options = 0;
1514
1515         if (init_apply_state(&apply_state, NULL, &lock_file))
1516                 die("BUG: init_apply_state() failed");
1517
1518         argv_array_push(&apply_opts, "apply");
1519         argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
1520
1521         opts_left = apply_parse_options(apply_opts.argc, apply_opts.argv,
1522                                         &apply_state, &force_apply, &options,
1523                                         NULL);
1524
1525         if (opts_left != 0)
1526                 die("unknown option passed through to git apply");
1527
1528         if (index_file) {
1529                 apply_state.index_file = index_file;
1530                 apply_state.cached = 1;
1531         } else
1532                 apply_state.check_index = 1;
1533
1534         /*
1535          * If we are allowed to fall back on 3-way merge, don't give false
1536          * errors during the initial attempt.
1537          */
1538         if (state->threeway && !index_file)
1539                 apply_state.apply_verbosity = verbosity_silent;
1540
1541         if (check_apply_state(&apply_state, force_apply))
1542                 die("BUG: check_apply_state() failed");
1543
1544         argv_array_push(&apply_paths, am_path(state, "patch"));
1545
1546         res = apply_all_patches(&apply_state, apply_paths.argc, apply_paths.argv, options);
1547
1548         argv_array_clear(&apply_paths);
1549         argv_array_clear(&apply_opts);
1550         clear_apply_state(&apply_state);
1551
1552         if (res)
1553                 return res;
1554
1555         if (index_file) {
1556                 /* Reload index as apply_all_patches() will have modified it. */
1557                 discard_cache();
1558                 read_cache_from(index_file);
1559         }
1560
1561         return 0;
1562 }
1563
1564 /**
1565  * Builds an index that contains just the blobs needed for a 3way merge.
1566  */
1567 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1568 {
1569         struct child_process cp = CHILD_PROCESS_INIT;
1570
1571         cp.git_cmd = 1;
1572         argv_array_push(&cp.args, "apply");
1573         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1574         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1575         argv_array_push(&cp.args, am_path(state, "patch"));
1576
1577         if (run_command(&cp))
1578                 return -1;
1579
1580         return 0;
1581 }
1582
1583 /**
1584  * Attempt a threeway merge, using index_path as the temporary index.
1585  */
1586 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1587 {
1588         struct object_id orig_tree, their_tree, our_tree;
1589         const struct object_id *bases[1] = { &orig_tree };
1590         struct merge_options o;
1591         struct commit *result;
1592         char *their_tree_name;
1593
1594         if (get_oid("HEAD", &our_tree) < 0)
1595                 hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
1596
1597         if (build_fake_ancestor(state, index_path))
1598                 return error("could not build fake ancestor");
1599
1600         discard_cache();
1601         read_cache_from(index_path);
1602
1603         if (write_index_as_tree(orig_tree.hash, &the_index, index_path, 0, NULL))
1604                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1605
1606         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1607
1608         if (!state->quiet) {
1609                 /*
1610                  * List paths that needed 3-way fallback, so that the user can
1611                  * review them with extra care to spot mismerges.
1612                  */
1613                 struct rev_info rev_info;
1614                 const char *diff_filter_str = "--diff-filter=AM";
1615
1616                 init_revisions(&rev_info, NULL);
1617                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1618                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1619                 add_pending_sha1(&rev_info, "HEAD", our_tree.hash, 0);
1620                 diff_setup_done(&rev_info.diffopt);
1621                 run_diff_index(&rev_info, 1);
1622         }
1623
1624         if (run_apply(state, index_path))
1625                 return error(_("Did you hand edit your patch?\n"
1626                                 "It does not apply to blobs recorded in its index."));
1627
1628         if (write_index_as_tree(their_tree.hash, &the_index, index_path, 0, NULL))
1629                 return error("could not write tree");
1630
1631         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1632
1633         discard_cache();
1634         read_cache();
1635
1636         /*
1637          * This is not so wrong. Depending on which base we picked, orig_tree
1638          * may be wildly different from ours, but their_tree has the same set of
1639          * wildly different changes in parts the patch did not touch, so
1640          * recursive ends up canceling them, saying that we reverted all those
1641          * changes.
1642          */
1643
1644         init_merge_options(&o);
1645
1646         o.branch1 = "HEAD";
1647         their_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
1648         o.branch2 = their_tree_name;
1649
1650         if (state->quiet)
1651                 o.verbosity = 0;
1652
1653         if (merge_recursive_generic(&o, &our_tree, &their_tree, 1, bases, &result)) {
1654                 rerere(state->allow_rerere_autoupdate);
1655                 free(their_tree_name);
1656                 return error(_("Failed to merge in the changes."));
1657         }
1658
1659         free(their_tree_name);
1660         return 0;
1661 }
1662
1663 /**
1664  * Commits the current index with state->msg as the commit message and
1665  * state->author_name, state->author_email and state->author_date as the author
1666  * information.
1667  */
1668 static void do_commit(const struct am_state *state)
1669 {
1670         struct object_id tree, parent, commit;
1671         const struct object_id *old_oid;
1672         struct commit_list *parents = NULL;
1673         const char *reflog_msg, *author;
1674         struct strbuf sb = STRBUF_INIT;
1675
1676         if (run_hook_le(NULL, "pre-applypatch", NULL))
1677                 exit(1);
1678
1679         if (write_cache_as_tree(tree.hash, 0, NULL))
1680                 die(_("git write-tree failed to write a tree"));
1681
1682         if (!get_sha1_commit("HEAD", parent.hash)) {
1683                 old_oid = &parent;
1684                 commit_list_insert(lookup_commit(parent.hash), &parents);
1685         } else {
1686                 old_oid = NULL;
1687                 say(state, stderr, _("applying to an empty history"));
1688         }
1689
1690         author = fmt_ident(state->author_name, state->author_email,
1691                         state->ignore_date ? NULL : state->author_date,
1692                         IDENT_STRICT);
1693
1694         if (state->committer_date_is_author_date)
1695                 setenv("GIT_COMMITTER_DATE",
1696                         state->ignore_date ? "" : state->author_date, 1);
1697
1698         if (commit_tree(state->msg, state->msg_len, tree.hash, parents, commit.hash,
1699                                 author, state->sign_commit))
1700                 die(_("failed to write commit object"));
1701
1702         reflog_msg = getenv("GIT_REFLOG_ACTION");
1703         if (!reflog_msg)
1704                 reflog_msg = "am";
1705
1706         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1707                         state->msg);
1708
1709         update_ref_oid(sb.buf, "HEAD", &commit, old_oid, 0,
1710                         UPDATE_REFS_DIE_ON_ERR);
1711
1712         if (state->rebasing) {
1713                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1714
1715                 assert(!is_null_oid(&state->orig_commit));
1716                 fprintf(fp, "%s ", oid_to_hex(&state->orig_commit));
1717                 fprintf(fp, "%s\n", oid_to_hex(&commit));
1718                 fclose(fp);
1719         }
1720
1721         run_hook_le(NULL, "post-applypatch", NULL);
1722
1723         strbuf_release(&sb);
1724 }
1725
1726 /**
1727  * Validates the am_state for resuming -- the "msg" and authorship fields must
1728  * be filled up.
1729  */
1730 static void validate_resume_state(const struct am_state *state)
1731 {
1732         if (!state->msg)
1733                 die(_("cannot resume: %s does not exist."),
1734                         am_path(state, "final-commit"));
1735
1736         if (!state->author_name || !state->author_email || !state->author_date)
1737                 die(_("cannot resume: %s does not exist."),
1738                         am_path(state, "author-script"));
1739 }
1740
1741 /**
1742  * Interactively prompt the user on whether the current patch should be
1743  * applied.
1744  *
1745  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1746  * skip it.
1747  */
1748 static int do_interactive(struct am_state *state)
1749 {
1750         assert(state->msg);
1751
1752         if (!isatty(0))
1753                 die(_("cannot be interactive without stdin connected to a terminal."));
1754
1755         for (;;) {
1756                 const char *reply;
1757
1758                 puts(_("Commit Body is:"));
1759                 puts("--------------------------");
1760                 printf("%s", state->msg);
1761                 puts("--------------------------");
1762
1763                 /*
1764                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1765                  * in your translation. The program will only accept English
1766                  * input at this point.
1767                  */
1768                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1769
1770                 if (!reply) {
1771                         continue;
1772                 } else if (*reply == 'y' || *reply == 'Y') {
1773                         return 0;
1774                 } else if (*reply == 'a' || *reply == 'A') {
1775                         state->interactive = 0;
1776                         return 0;
1777                 } else if (*reply == 'n' || *reply == 'N') {
1778                         return 1;
1779                 } else if (*reply == 'e' || *reply == 'E') {
1780                         struct strbuf msg = STRBUF_INIT;
1781
1782                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1783                                 free(state->msg);
1784                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1785                         }
1786                         strbuf_release(&msg);
1787                 } else if (*reply == 'v' || *reply == 'V') {
1788                         const char *pager = git_pager(1);
1789                         struct child_process cp = CHILD_PROCESS_INIT;
1790
1791                         if (!pager)
1792                                 pager = "cat";
1793                         prepare_pager_args(&cp, pager);
1794                         argv_array_push(&cp.args, am_path(state, "patch"));
1795                         run_command(&cp);
1796                 }
1797         }
1798 }
1799
1800 /**
1801  * Applies all queued mail.
1802  *
1803  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1804  * well as the state directory's "patch" file is used as-is for applying the
1805  * patch and committing it.
1806  */
1807 static void am_run(struct am_state *state, int resume)
1808 {
1809         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1810         struct strbuf sb = STRBUF_INIT;
1811
1812         unlink(am_path(state, "dirtyindex"));
1813
1814         refresh_and_write_cache();
1815
1816         if (index_has_changes(&sb)) {
1817                 write_state_bool(state, "dirtyindex", 1);
1818                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1819         }
1820
1821         strbuf_release(&sb);
1822
1823         while (state->cur <= state->last) {
1824                 const char *mail = am_path(state, msgnum(state));
1825                 int apply_status;
1826
1827                 reset_ident_date();
1828
1829                 if (!file_exists(mail))
1830                         goto next;
1831
1832                 if (resume) {
1833                         validate_resume_state(state);
1834                 } else {
1835                         int skip;
1836
1837                         if (state->rebasing)
1838                                 skip = parse_mail_rebase(state, mail);
1839                         else
1840                                 skip = parse_mail(state, mail);
1841
1842                         if (skip)
1843                                 goto next; /* mail should be skipped */
1844
1845                         if (state->signoff)
1846                                 am_append_signoff(state);
1847
1848                         write_author_script(state);
1849                         write_commit_msg(state);
1850                 }
1851
1852                 if (state->interactive && do_interactive(state))
1853                         goto next;
1854
1855                 if (run_applypatch_msg_hook(state))
1856                         exit(1);
1857
1858                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1859
1860                 apply_status = run_apply(state, NULL);
1861
1862                 if (apply_status && state->threeway) {
1863                         struct strbuf sb = STRBUF_INIT;
1864
1865                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1866                         apply_status = fall_back_threeway(state, sb.buf);
1867                         strbuf_release(&sb);
1868
1869                         /*
1870                          * Applying the patch to an earlier tree and merging
1871                          * the result may have produced the same tree as ours.
1872                          */
1873                         if (!apply_status && !index_has_changes(NULL)) {
1874                                 say(state, stdout, _("No changes -- Patch already applied."));
1875                                 goto next;
1876                         }
1877                 }
1878
1879                 if (apply_status) {
1880                         int advice_amworkdir = 1;
1881
1882                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1883                                 linelen(state->msg), state->msg);
1884
1885                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1886
1887                         if (advice_amworkdir)
1888                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1889                                                 am_path(state, "patch"));
1890
1891                         die_user_resolve(state);
1892                 }
1893
1894                 do_commit(state);
1895
1896 next:
1897                 am_next(state);
1898
1899                 if (resume)
1900                         am_load(state);
1901                 resume = 0;
1902         }
1903
1904         if (!is_empty_file(am_path(state, "rewritten"))) {
1905                 assert(state->rebasing);
1906                 copy_notes_for_rebase(state);
1907                 run_post_rewrite_hook(state);
1908         }
1909
1910         /*
1911          * In rebasing mode, it's up to the caller to take care of
1912          * housekeeping.
1913          */
1914         if (!state->rebasing) {
1915                 am_destroy(state);
1916                 close_all_packs();
1917                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1918         }
1919 }
1920
1921 /**
1922  * Resume the current am session after patch application failure. The user did
1923  * all the hard work, and we do not have to do any patch application. Just
1924  * trust and commit what the user has in the index and working tree.
1925  */
1926 static void am_resolve(struct am_state *state)
1927 {
1928         validate_resume_state(state);
1929
1930         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1931
1932         if (!index_has_changes(NULL)) {
1933                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1934                         "If there is nothing left to stage, chances are that something else\n"
1935                         "already introduced the same changes; you might want to skip this patch."));
1936                 die_user_resolve(state);
1937         }
1938
1939         if (unmerged_cache()) {
1940                 printf_ln(_("You still have unmerged paths in your index.\n"
1941                         "Did you forget to use 'git add'?"));
1942                 die_user_resolve(state);
1943         }
1944
1945         if (state->interactive) {
1946                 write_index_patch(state);
1947                 if (do_interactive(state))
1948                         goto next;
1949         }
1950
1951         rerere(0);
1952
1953         do_commit(state);
1954
1955 next:
1956         am_next(state);
1957         am_load(state);
1958         am_run(state, 0);
1959 }
1960
1961 /**
1962  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1963  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1964  * failure.
1965  */
1966 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1967 {
1968         struct lock_file *lock_file;
1969         struct unpack_trees_options opts;
1970         struct tree_desc t[2];
1971
1972         if (parse_tree(head) || parse_tree(remote))
1973                 return -1;
1974
1975         lock_file = xcalloc(1, sizeof(struct lock_file));
1976         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1977
1978         refresh_cache(REFRESH_QUIET);
1979
1980         memset(&opts, 0, sizeof(opts));
1981         opts.head_idx = 1;
1982         opts.src_index = &the_index;
1983         opts.dst_index = &the_index;
1984         opts.update = 1;
1985         opts.merge = 1;
1986         opts.reset = reset;
1987         opts.fn = twoway_merge;
1988         init_tree_desc(&t[0], head->buffer, head->size);
1989         init_tree_desc(&t[1], remote->buffer, remote->size);
1990
1991         if (unpack_trees(2, t, &opts)) {
1992                 rollback_lock_file(lock_file);
1993                 return -1;
1994         }
1995
1996         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1997                 die(_("unable to write new index file"));
1998
1999         return 0;
2000 }
2001
2002 /**
2003  * Merges a tree into the index. The index's stat info will take precedence
2004  * over the merged tree's. Returns 0 on success, -1 on failure.
2005  */
2006 static int merge_tree(struct tree *tree)
2007 {
2008         struct lock_file *lock_file;
2009         struct unpack_trees_options opts;
2010         struct tree_desc t[1];
2011
2012         if (parse_tree(tree))
2013                 return -1;
2014
2015         lock_file = xcalloc(1, sizeof(struct lock_file));
2016         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
2017
2018         memset(&opts, 0, sizeof(opts));
2019         opts.head_idx = 1;
2020         opts.src_index = &the_index;
2021         opts.dst_index = &the_index;
2022         opts.merge = 1;
2023         opts.fn = oneway_merge;
2024         init_tree_desc(&t[0], tree->buffer, tree->size);
2025
2026         if (unpack_trees(1, t, &opts)) {
2027                 rollback_lock_file(lock_file);
2028                 return -1;
2029         }
2030
2031         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2032                 die(_("unable to write new index file"));
2033
2034         return 0;
2035 }
2036
2037 /**
2038  * Clean the index without touching entries that are not modified between
2039  * `head` and `remote`.
2040  */
2041 static int clean_index(const struct object_id *head, const struct object_id *remote)
2042 {
2043         struct tree *head_tree, *remote_tree, *index_tree;
2044         struct object_id index;
2045
2046         head_tree = parse_tree_indirect(head->hash);
2047         if (!head_tree)
2048                 return error(_("Could not parse object '%s'."), oid_to_hex(head));
2049
2050         remote_tree = parse_tree_indirect(remote->hash);
2051         if (!remote_tree)
2052                 return error(_("Could not parse object '%s'."), oid_to_hex(remote));
2053
2054         read_cache_unmerged();
2055
2056         if (fast_forward_to(head_tree, head_tree, 1))
2057                 return -1;
2058
2059         if (write_cache_as_tree(index.hash, 0, NULL))
2060                 return -1;
2061
2062         index_tree = parse_tree_indirect(index.hash);
2063         if (!index_tree)
2064                 return error(_("Could not parse object '%s'."), oid_to_hex(&index));
2065
2066         if (fast_forward_to(index_tree, remote_tree, 0))
2067                 return -1;
2068
2069         if (merge_tree(remote_tree))
2070                 return -1;
2071
2072         remove_branch_state();
2073
2074         return 0;
2075 }
2076
2077 /**
2078  * Resets rerere's merge resolution metadata.
2079  */
2080 static void am_rerere_clear(void)
2081 {
2082         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2083         rerere_clear(&merge_rr);
2084         string_list_clear(&merge_rr, 1);
2085 }
2086
2087 /**
2088  * Resume the current am session by skipping the current patch.
2089  */
2090 static void am_skip(struct am_state *state)
2091 {
2092         struct object_id head;
2093
2094         am_rerere_clear();
2095
2096         if (get_oid("HEAD", &head))
2097                 hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
2098
2099         if (clean_index(&head, &head))
2100                 die(_("failed to clean index"));
2101
2102         am_next(state);
2103         am_load(state);
2104         am_run(state, 0);
2105 }
2106
2107 /**
2108  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2109  *
2110  * It is not safe to reset HEAD when:
2111  * 1. git-am previously failed because the index was dirty.
2112  * 2. HEAD has moved since git-am previously failed.
2113  */
2114 static int safe_to_abort(const struct am_state *state)
2115 {
2116         struct strbuf sb = STRBUF_INIT;
2117         struct object_id abort_safety, head;
2118
2119         if (file_exists(am_path(state, "dirtyindex")))
2120                 return 0;
2121
2122         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2123                 if (get_oid_hex(sb.buf, &abort_safety))
2124                         die(_("could not parse %s"), am_path(state, "abort-safety"));
2125         } else
2126                 oidclr(&abort_safety);
2127
2128         if (get_oid("HEAD", &head))
2129                 oidclr(&head);
2130
2131         if (!oidcmp(&head, &abort_safety))
2132                 return 1;
2133
2134         warning(_("You seem to have moved HEAD since the last 'am' failure.\n"
2135                 "Not rewinding to ORIG_HEAD"));
2136
2137         return 0;
2138 }
2139
2140 /**
2141  * Aborts the current am session if it is safe to do so.
2142  */
2143 static void am_abort(struct am_state *state)
2144 {
2145         struct object_id curr_head, orig_head;
2146         int has_curr_head, has_orig_head;
2147         char *curr_branch;
2148
2149         if (!safe_to_abort(state)) {
2150                 am_destroy(state);
2151                 return;
2152         }
2153
2154         am_rerere_clear();
2155
2156         curr_branch = resolve_refdup("HEAD", 0, curr_head.hash, NULL);
2157         has_curr_head = !is_null_oid(&curr_head);
2158         if (!has_curr_head)
2159                 hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
2160
2161         has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
2162         if (!has_orig_head)
2163                 hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
2164
2165         clean_index(&curr_head, &orig_head);
2166
2167         if (has_orig_head)
2168                 update_ref_oid("am --abort", "HEAD", &orig_head,
2169                                 has_curr_head ? &curr_head : NULL, 0,
2170                                 UPDATE_REFS_DIE_ON_ERR);
2171         else if (curr_branch)
2172                 delete_ref(NULL, curr_branch, NULL, REF_NODEREF);
2173
2174         free(curr_branch);
2175         am_destroy(state);
2176 }
2177
2178 /**
2179  * parse_options() callback that validates and sets opt->value to the
2180  * PATCH_FORMAT_* enum value corresponding to `arg`.
2181  */
2182 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2183 {
2184         int *opt_value = opt->value;
2185
2186         if (!strcmp(arg, "mbox"))
2187                 *opt_value = PATCH_FORMAT_MBOX;
2188         else if (!strcmp(arg, "stgit"))
2189                 *opt_value = PATCH_FORMAT_STGIT;
2190         else if (!strcmp(arg, "stgit-series"))
2191                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2192         else if (!strcmp(arg, "hg"))
2193                 *opt_value = PATCH_FORMAT_HG;
2194         else if (!strcmp(arg, "mboxrd"))
2195                 *opt_value = PATCH_FORMAT_MBOXRD;
2196         else
2197                 return error(_("Invalid value for --patch-format: %s"), arg);
2198         return 0;
2199 }
2200
2201 enum resume_mode {
2202         RESUME_FALSE = 0,
2203         RESUME_APPLY,
2204         RESUME_RESOLVED,
2205         RESUME_SKIP,
2206         RESUME_ABORT
2207 };
2208
2209 static int git_am_config(const char *k, const char *v, void *cb)
2210 {
2211         int status;
2212
2213         status = git_gpg_config(k, v, NULL);
2214         if (status)
2215                 return status;
2216
2217         return git_default_config(k, v, NULL);
2218 }
2219
2220 int cmd_am(int argc, const char **argv, const char *prefix)
2221 {
2222         struct am_state state;
2223         int binary = -1;
2224         int keep_cr = -1;
2225         int patch_format = PATCH_FORMAT_UNKNOWN;
2226         enum resume_mode resume = RESUME_FALSE;
2227         int in_progress;
2228
2229         const char * const usage[] = {
2230                 N_("git am [<options>] [(<mbox> | <Maildir>)...]"),
2231                 N_("git am [<options>] (--continue | --skip | --abort)"),
2232                 NULL
2233         };
2234
2235         struct option options[] = {
2236                 OPT_BOOL('i', "interactive", &state.interactive,
2237                         N_("run interactively")),
2238                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2239                         N_("historical option -- no-op")),
2240                 OPT_BOOL('3', "3way", &state.threeway,
2241                         N_("allow fall back on 3way merging if needed")),
2242                 OPT__QUIET(&state.quiet, N_("be quiet")),
2243                 OPT_SET_INT('s', "signoff", &state.signoff,
2244                         N_("add a Signed-off-by line to the commit message"),
2245                         SIGNOFF_EXPLICIT),
2246                 OPT_BOOL('u', "utf8", &state.utf8,
2247                         N_("recode into utf8 (default)")),
2248                 OPT_SET_INT('k', "keep", &state.keep,
2249                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2250                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2251                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2252                 OPT_BOOL('m', "message-id", &state.message_id,
2253                         N_("pass -m flag to git-mailinfo")),
2254                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2255                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2256                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2257                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2258                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2259                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2260                 OPT_BOOL('c', "scissors", &state.scissors,
2261                         N_("strip everything before a scissors line")),
2262                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2263                         N_("pass it through git-apply"),
2264                         0),
2265                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2266                         N_("pass it through git-apply"),
2267                         PARSE_OPT_NOARG),
2268                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2269                         N_("pass it through git-apply"),
2270                         PARSE_OPT_NOARG),
2271                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2272                         N_("pass it through git-apply"),
2273                         0),
2274                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2275                         N_("pass it through git-apply"),
2276                         0),
2277                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2278                         N_("pass it through git-apply"),
2279                         0),
2280                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2281                         N_("pass it through git-apply"),
2282                         0),
2283                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2284                         N_("pass it through git-apply"),
2285                         0),
2286                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2287                         N_("format the patch(es) are in"),
2288                         parse_opt_patchformat),
2289                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2290                         N_("pass it through git-apply"),
2291                         PARSE_OPT_NOARG),
2292                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2293                         N_("override error message when patch failure occurs")),
2294                 OPT_CMDMODE(0, "continue", &resume,
2295                         N_("continue applying patches after resolving a conflict"),
2296                         RESUME_RESOLVED),
2297                 OPT_CMDMODE('r', "resolved", &resume,
2298                         N_("synonyms for --continue"),
2299                         RESUME_RESOLVED),
2300                 OPT_CMDMODE(0, "skip", &resume,
2301                         N_("skip the current patch"),
2302                         RESUME_SKIP),
2303                 OPT_CMDMODE(0, "abort", &resume,
2304                         N_("restore the original branch and abort the patching operation."),
2305                         RESUME_ABORT),
2306                 OPT_BOOL(0, "committer-date-is-author-date",
2307                         &state.committer_date_is_author_date,
2308                         N_("lie about committer date")),
2309                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2310                         N_("use current timestamp for author date")),
2311                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2312                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2313                   N_("GPG-sign commits"),
2314                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2315                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2316                         N_("(internal use for git-rebase)")),
2317                 OPT_END()
2318         };
2319
2320         git_config(git_am_config, NULL);
2321
2322         am_state_init(&state, git_path("rebase-apply"));
2323
2324         in_progress = am_in_progress(&state);
2325         if (in_progress)
2326                 am_load(&state);
2327
2328         argc = parse_options(argc, argv, prefix, options, usage, 0);
2329
2330         if (binary >= 0)
2331                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2332                                 "it will be removed. Please do not use it anymore."));
2333
2334         /* Ensure a valid committer ident can be constructed */
2335         git_committer_info(IDENT_STRICT);
2336
2337         if (read_index_preload(&the_index, NULL) < 0)
2338                 die(_("failed to read the index"));
2339
2340         if (in_progress) {
2341                 /*
2342                  * Catch user error to feed us patches when there is a session
2343                  * in progress:
2344                  *
2345                  * 1. mbox path(s) are provided on the command-line.
2346                  * 2. stdin is not a tty: the user is trying to feed us a patch
2347                  *    from standard input. This is somewhat unreliable -- stdin
2348                  *    could be /dev/null for example and the caller did not
2349                  *    intend to feed us a patch but wanted to continue
2350                  *    unattended.
2351                  */
2352                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2353                         die(_("previous rebase directory %s still exists but mbox given."),
2354                                 state.dir);
2355
2356                 if (resume == RESUME_FALSE)
2357                         resume = RESUME_APPLY;
2358
2359                 if (state.signoff == SIGNOFF_EXPLICIT)
2360                         am_append_signoff(&state);
2361         } else {
2362                 struct argv_array paths = ARGV_ARRAY_INIT;
2363                 int i;
2364
2365                 /*
2366                  * Handle stray state directory in the independent-run case. In
2367                  * the --rebasing case, it is up to the caller to take care of
2368                  * stray directories.
2369                  */
2370                 if (file_exists(state.dir) && !state.rebasing) {
2371                         if (resume == RESUME_ABORT) {
2372                                 am_destroy(&state);
2373                                 am_state_release(&state);
2374                                 return 0;
2375                         }
2376
2377                         die(_("Stray %s directory found.\n"
2378                                 "Use \"git am --abort\" to remove it."),
2379                                 state.dir);
2380                 }
2381
2382                 if (resume)
2383                         die(_("Resolve operation not in progress, we are not resuming."));
2384
2385                 for (i = 0; i < argc; i++) {
2386                         if (is_absolute_path(argv[i]) || !prefix)
2387                                 argv_array_push(&paths, argv[i]);
2388                         else
2389                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2390                 }
2391
2392                 am_setup(&state, patch_format, paths.argv, keep_cr);
2393
2394                 argv_array_clear(&paths);
2395         }
2396
2397         switch (resume) {
2398         case RESUME_FALSE:
2399                 am_run(&state, 0);
2400                 break;
2401         case RESUME_APPLY:
2402                 am_run(&state, 1);
2403                 break;
2404         case RESUME_RESOLVED:
2405                 am_resolve(&state);
2406                 break;
2407         case RESUME_SKIP:
2408                 am_skip(&state);
2409                 break;
2410         case RESUME_ABORT:
2411                 am_abort(&state);
2412                 break;
2413         default:
2414                 die("BUG: invalid resume value");
2415         }
2416
2417         am_state_release(&state);
2418
2419         return 0;
2420 }