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   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
  32 /**
  33  * Returns 1 if the file is empty or does not exist, 0 otherwise.
  34  */
  35 static int is_empty_file(const char *filename)
  36 {
  37         struct stat st;
  38
  39         if (stat(filename, &st) < 0) {
  40                 if (errno == ENOENT)
  41                         return 1;
  42                 die_errno(_("could not stat %s"), filename);
  43         }
  44
  45         return !st.st_size;
  46 }
  47
  48 /**
  49  * Returns the length of the first line of msg.
  50  */
  51 static int linelen(const char *msg)
  52 {
  53         return strchrnul(msg, '\n') - msg;
  54 }
  55
  56 /**
  57  * Returns true if `str` consists of only whitespace, false otherwise.
  58  */
  59 static int str_isspace(const char *str)
  60 {
  61         for (; *str; str++)
  62                 if (!isspace(*str))
  63                         return 0;
  64
  65         return 1;
  66 }
  67
  68 enum patch_format {
  69         PATCH_FORMAT_UNKNOWN = 0,
  70         PATCH_FORMAT_MBOX,
  71         PATCH_FORMAT_STGIT,
  72         PATCH_FORMAT_STGIT_SERIES,
  73         PATCH_FORMAT_HG
  74 };
  75
  76 enum keep_type {
  77         KEEP_FALSE = 0,
  78         KEEP_TRUE,      /* pass -k flag to git-mailinfo */
  79         KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
  80 };
  81
  82 enum scissors_type {
  83         SCISSORS_UNSET = -1,
  84         SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
  85         SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
  86 };
  87
  88 enum signoff_type {
  89         SIGNOFF_FALSE = 0,
  90         SIGNOFF_TRUE = 1,
  91         SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
  92 };
  93
  94 struct am_state {
  95         /* state directory path */
  96         char *dir;
  97
  98         /* current and last patch numbers, 1-indexed */
  99         int cur;
 100         int last;
 101
 102         /* commit metadata and message */
 103         char *author_name;
 104         char *author_email;
 105         char *author_date;
 106         char *msg;
 107         size_t msg_len;
 108
 109         /* when --rebasing, records the original commit the patch came from */
 110         unsigned char orig_commit[GIT_SHA1_RAWSZ];
 111
 112         /* number of digits in patch filename */
 113         int prec;
 114
 115         /* various operating modes and command line options */
 116         int interactive;
 117         int threeway;
 118         int quiet;
 119         int signoff; /* enum signoff_type */
 120         int utf8;
 121         int keep; /* enum keep_type */
 122         int message_id;
 123         int scissors; /* enum scissors_type */
 124         struct argv_array git_apply_opts;
 125         const char *resolvemsg;
 126         int committer_date_is_author_date;
 127         int ignore_date;
 128         int allow_rerere_autoupdate;
 129         const char *sign_commit;
 130         int rebasing;
 131 };
 132
 133 /**
 134  * Initializes am_state with the default values. The state directory is set to
 135  * dir.
 136  */
 137 static void am_state_init(struct am_state *state, const char *dir)
 138 {
 139         int gpgsign;
 140
 141         memset(state, 0, sizeof(*state));
 142
 143         assert(dir);
 144         state->dir = xstrdup(dir);
 145
 146         state->prec = 4;
 147
 148         git_config_get_bool("am.threeway", &state->threeway);
 149
 150         state->utf8 = 1;
 151
 152         git_config_get_bool("am.messageid", &state->message_id);
 153
 154         state->scissors = SCISSORS_UNSET;
 155
 156         argv_array_init(&state->git_apply_opts);
 157
 158         if (!git_config_get_bool("commit.gpgsign", &gpgsign))
 159                 state->sign_commit = gpgsign ? "" : NULL;
 160 }
 161
 162 /**
 163  * Releases memory allocated by an am_state.
 164  */
 165 static void am_state_release(struct am_state *state)
 166 {
 167         free(state->dir);
 168         free(state->author_name);
 169         free(state->author_email);
 170         free(state->author_date);
 171         free(state->msg);
 172         argv_array_clear(&state->git_apply_opts);
 173 }
 174
 175 /**
 176  * Returns path relative to the am_state directory.
 177  */
 178 static inline const char *am_path(const struct am_state *state, const char *path)
 179 {
 180         return mkpath("%s/%s", state->dir, path);
 181 }
 182
 183 /**
 184  * For convenience to call write_file()
 185  */
 186 static int write_state_text(const struct am_state *state,
 187                             const char *name, const char *string)
 188 {
 189         return write_file(am_path(state, name), "%s", string);
 190 }
 191
 192 static int write_state_count(const struct am_state *state,
 193                              const char *name, int value)
 194 {
 195         return write_file(am_path(state, name), "%d", value);
 196 }
 197
 198 static int write_state_bool(const struct am_state *state,
 199                             const char *name, int value)
 200 {
 201         return write_state_text(state, name, value ? "t" : "f");
 202 }
 203
 204 /**
 205  * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
 206  * at the end.
 207  */
 208 static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
 209 {
 210         va_list ap;
 211
 212         va_start(ap, fmt);
 213         if (!state->quiet) {
 214                 vfprintf(fp, fmt, ap);
 215                 putc('\n', fp);
 216         }
 217         va_end(ap);
 218 }
 219
 220 /**
 221  * Returns 1 if there is an am session in progress, 0 otherwise.
 222  */
 223 static int am_in_progress(const struct am_state *state)
 224 {
 225         struct stat st;
 226
 227         if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
 228                 return 0;
 229         if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
 230                 return 0;
 231         if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
 232                 return 0;
 233         return 1;
 234 }
 235
 236 /**
 237  * Reads the contents of `file` in the `state` directory into `sb`. Returns the
 238  * number of bytes read on success, -1 if the file does not exist. If `trim` is
 239  * set, trailing whitespace will be removed.
 240  */
 241 static int read_state_file(struct strbuf *sb, const struct am_state *state,
 242                         const char *file, int trim)
 243 {
 244         strbuf_reset(sb);
 245
 246         if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
 247                 if (trim)
 248                         strbuf_trim(sb);
 249
 250                 return sb->len;
 251         }
 252
 253         if (errno == ENOENT)
 254                 return -1;
 255
 256         die_errno(_("could not read '%s'"), am_path(state, file));
 257 }
 258
 259 /**
 260  * Reads a KEY=VALUE shell variable assignment from `fp`, returning the VALUE
 261  * as a newly-allocated string. VALUE must be a quoted string, and the KEY must
 262  * match `key`. Returns NULL on failure.
 263  *
 264  * This is used by read_author_script() to read the GIT_AUTHOR_* variables from
 265  * the author-script.
 266  */
 267 static char *read_shell_var(FILE *fp, const char *key)
 268 {
 269         struct strbuf sb = STRBUF_INIT;
 270         const char *str;
 271
 272         if (strbuf_getline_lf(&sb, fp))
 273                 goto fail;
 274
 275         if (!skip_prefix(sb.buf, key, &str))
 276                 goto fail;
 277
 278         if (!skip_prefix(str, "=", &str))
 279                 goto fail;
 280
 281         strbuf_remove(&sb, 0, str - sb.buf);
 282
 283         str = sq_dequote(sb.buf);
 284         if (!str)
 285                 goto fail;
 286
 287         return strbuf_detach(&sb, NULL);
 288
 289 fail:
 290         strbuf_release(&sb);
 291         return NULL;
 292 }
 293
 294 /**
 295  * Reads and parses the state directory's "author-script" file, and sets
 296  * state->author_name, state->author_email and state->author_date accordingly.
 297  * Returns 0 on success, -1 if the file could not be parsed.
 298  *
 299  * The author script is of the format:
 300  *
 301  *      GIT_AUTHOR_NAME='$author_name'
 302  *      GIT_AUTHOR_EMAIL='$author_email'
 303  *      GIT_AUTHOR_DATE='$author_date'
 304  *
 305  * where $author_name, $author_email and $author_date are quoted. We are strict
 306  * with our parsing, as the file was meant to be eval'd in the old git-am.sh
 307  * script, and thus if the file differs from what this function expects, it is
 308  * better to bail out than to do something that the user does not expect.
 309  */
 310 static int read_author_script(struct am_state *state)
 311 {
 312         const char *filename = am_path(state, "author-script");
 313         FILE *fp;
 314
 315         assert(!state->author_name);
 316         assert(!state->author_email);
 317         assert(!state->author_date);
 318
 319         fp = fopen(filename, "r");
 320         if (!fp) {
 321                 if (errno == ENOENT)
 322                         return 0;
 323                 die_errno(_("could not open '%s' for reading"), filename);
 324         }
 325
 326         state->author_name = read_shell_var(fp, "GIT_AUTHOR_NAME");
 327         if (!state->author_name) {
 328                 fclose(fp);
 329                 return -1;
 330         }
 331
 332         state->author_email = read_shell_var(fp, "GIT_AUTHOR_EMAIL");
 333         if (!state->author_email) {
 334                 fclose(fp);
 335                 return -1;
 336         }
 337
 338         state->author_date = read_shell_var(fp, "GIT_AUTHOR_DATE");
 339         if (!state->author_date) {
 340                 fclose(fp);
 341                 return -1;
 342         }
 343
 344         if (fgetc(fp) != EOF) {
 345                 fclose(fp);
 346                 return -1;
 347         }
 348
 349         fclose(fp);
 350         return 0;
 351 }
 352
 353 /**
 354  * Saves state->author_name, state->author_email and state->author_date in the
 355  * state directory's "author-script" file.
 356  */
 357 static void write_author_script(const struct am_state *state)
 358 {
 359         struct strbuf sb = STRBUF_INIT;
 360
 361         strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
 362         sq_quote_buf(&sb, state->author_name);
 363         strbuf_addch(&sb, '\n');
 364
 365         strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
 366         sq_quote_buf(&sb, state->author_email);
 367         strbuf_addch(&sb, '\n');
 368
 369         strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
 370         sq_quote_buf(&sb, state->author_date);
 371         strbuf_addch(&sb, '\n');
 372
 373         write_state_text(state, "author-script", sb.buf);
 374
 375         strbuf_release(&sb);
 376 }
 377
 378 /**
 379  * Reads the commit message from the state directory's "final-commit" file,
 380  * setting state->msg to its contents and state->msg_len to the length of its
 381  * contents in bytes.
 382  *
 383  * Returns 0 on success, -1 if the file does not exist.
 384  */
 385 static int read_commit_msg(struct am_state *state)
 386 {
 387         struct strbuf sb = STRBUF_INIT;
 388
 389         assert(!state->msg);
 390
 391         if (read_state_file(&sb, state, "final-commit", 0) < 0) {
 392                 strbuf_release(&sb);
 393                 return -1;
 394         }
 395
 396         state->msg = strbuf_detach(&sb, &state->msg_len);
 397         return 0;
 398 }
 399
 400 /**
 401  * Saves state->msg in the state directory's "final-commit" file.
 402  */
 403 static void write_commit_msg(const struct am_state *state)
 404 {
 405         int fd;
 406         const char *filename = am_path(state, "final-commit");
 407
 408         fd = xopen(filename, O_WRONLY | O_CREAT, 0666);
 409         if (write_in_full(fd, state->msg, state->msg_len) < 0)
 410                 die_errno(_("could not write to %s"), filename);
 411         close(fd);
 412 }
 413
 414 /**
 415  * Loads state from disk.
 416  */
 417 static void am_load(struct am_state *state)
 418 {
 419         struct strbuf sb = STRBUF_INIT;
 420
 421         if (read_state_file(&sb, state, "next", 1) < 0)
 422                 die("BUG: state file 'next' does not exist");
 423         state->cur = strtol(sb.buf, NULL, 10);
 424
 425         if (read_state_file(&sb, state, "last", 1) < 0)
 426                 die("BUG: state file 'last' does not exist");
 427         state->last = strtol(sb.buf, NULL, 10);
 428
 429         if (read_author_script(state) < 0)
 430                 die(_("could not parse author script"));
 431
 432         read_commit_msg(state);
 433
 434         if (read_state_file(&sb, state, "original-commit", 1) < 0)
 435                 hashclr(state->orig_commit);
 436         else if (get_sha1_hex(sb.buf, state->orig_commit) < 0)
 437                 die(_("could not parse %s"), am_path(state, "original-commit"));
 438
 439         read_state_file(&sb, state, "threeway", 1);
 440         state->threeway = !strcmp(sb.buf, "t");
 441
 442         read_state_file(&sb, state, "quiet", 1);
 443         state->quiet = !strcmp(sb.buf, "t");
 444
 445         read_state_file(&sb, state, "sign", 1);
 446         state->signoff = !strcmp(sb.buf, "t");
 447
 448         read_state_file(&sb, state, "utf8", 1);
 449         state->utf8 = !strcmp(sb.buf, "t");
 450
 451         read_state_file(&sb, state, "keep", 1);
 452         if (!strcmp(sb.buf, "t"))
 453                 state->keep = KEEP_TRUE;
 454         else if (!strcmp(sb.buf, "b"))
 455                 state->keep = KEEP_NON_PATCH;
 456         else
 457                 state->keep = KEEP_FALSE;
 458
 459         read_state_file(&sb, state, "messageid", 1);
 460         state->message_id = !strcmp(sb.buf, "t");
 461
 462         read_state_file(&sb, state, "scissors", 1);
 463         if (!strcmp(sb.buf, "t"))
 464                 state->scissors = SCISSORS_TRUE;
 465         else if (!strcmp(sb.buf, "f"))
 466                 state->scissors = SCISSORS_FALSE;
 467         else
 468                 state->scissors = SCISSORS_UNSET;
 469
 470         read_state_file(&sb, state, "apply-opt", 1);
 471         argv_array_clear(&state->git_apply_opts);
 472         if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
 473                 die(_("could not parse %s"), am_path(state, "apply-opt"));
 474
 475         state->rebasing = !!file_exists(am_path(state, "rebasing"));
 476
 477         strbuf_release(&sb);
 478 }
 479
 480 /**
 481  * Removes the am_state directory, forcefully terminating the current am
 482  * session.
 483  */
 484 static void am_destroy(const struct am_state *state)
 485 {
 486         struct strbuf sb = STRBUF_INIT;
 487
 488         strbuf_addstr(&sb, state->dir);
 489         remove_dir_recursively(&sb, 0);
 490         strbuf_release(&sb);
 491 }
 492
 493 /**
 494  * Runs applypatch-msg hook. Returns its exit code.
 495  */
 496 static int run_applypatch_msg_hook(struct am_state *state)
 497 {
 498         int ret;
 499
 500         assert(state->msg);
 501         ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
 502
 503         if (!ret) {
 504                 free(state->msg);
 505                 state->msg = NULL;
 506                 if (read_commit_msg(state) < 0)
 507                         die(_("'%s' was deleted by the applypatch-msg hook"),
 508                                 am_path(state, "final-commit"));
 509         }
 510
 511         return ret;
 512 }
 513
 514 /**
 515  * Runs post-rewrite hook. Returns it exit code.
 516  */
 517 static int run_post_rewrite_hook(const struct am_state *state)
 518 {
 519         struct child_process cp = CHILD_PROCESS_INIT;
 520         const char *hook = find_hook("post-rewrite");
 521         int ret;
 522
 523         if (!hook)
 524                 return 0;
 525
 526         argv_array_push(&cp.args, hook);
 527         argv_array_push(&cp.args, "rebase");
 528
 529         cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
 530         cp.stdout_to_stderr = 1;
 531
 532         ret = run_command(&cp);
 533
 534         close(cp.in);
 535         return ret;
 536 }
 537
 538 /**
 539  * Reads the state directory's "rewritten" file, and copies notes from the old
 540  * commits listed in the file to their rewritten commits.
 541  *
 542  * Returns 0 on success, -1 on failure.
 543  */
 544 static int copy_notes_for_rebase(const struct am_state *state)
 545 {
 546         struct notes_rewrite_cfg *c;
 547         struct strbuf sb = STRBUF_INIT;
 548         const char *invalid_line = _("Malformed input line: '%s'.");
 549         const char *msg = "Notes added by 'git rebase'";
 550         FILE *fp;
 551         int ret = 0;
 552
 553         assert(state->rebasing);
 554
 555         c = init_copy_notes_for_rewrite("rebase");
 556         if (!c)
 557                 return 0;
 558
 559         fp = xfopen(am_path(state, "rewritten"), "r");
 560
 561         while (!strbuf_getline_lf(&sb, fp)) {
 562                 unsigned char from_obj[GIT_SHA1_RAWSZ], to_obj[GIT_SHA1_RAWSZ];
 563
 564                 if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
 565                         ret = error(invalid_line, sb.buf);
 566                         goto finish;
 567                 }
 568
 569                 if (get_sha1_hex(sb.buf, from_obj)) {
 570                         ret = error(invalid_line, sb.buf);
 571                         goto finish;
 572                 }
 573
 574                 if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
 575                         ret = error(invalid_line, sb.buf);
 576                         goto finish;
 577                 }
 578
 579                 if (get_sha1_hex(sb.buf + GIT_SHA1_HEXSZ + 1, to_obj)) {
 580                         ret = error(invalid_line, sb.buf);
 581                         goto finish;
 582                 }
 583
 584                 if (copy_note_for_rewrite(c, from_obj, to_obj))
 585                         ret = error(_("Failed to copy notes from '%s' to '%s'"),
 586                                         sha1_to_hex(from_obj), sha1_to_hex(to_obj));
 587         }
 588
 589 finish:
 590         finish_copy_notes_for_rewrite(c, msg);
 591         fclose(fp);
 592         strbuf_release(&sb);
 593         return ret;
 594 }
 595
 596 /**
 597  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
 598  * non-indented lines and checking if they look like they begin with valid
 599  * header field names.
 600  *
 601  * Returns 1 if the file looks like a piece of mail, 0 otherwise.
 602  */
 603 static int is_mail(FILE *fp)
 604 {
 605         const char *header_regex = "^[!-9;-~]+:";
 606         struct strbuf sb = STRBUF_INIT;
 607         regex_t regex;
 608         int ret = 1;
 609
 610         if (fseek(fp, 0L, SEEK_SET))
 611                 die_errno(_("fseek failed"));
 612
 613         if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
 614                 die("invalid pattern: %s", header_regex);
 615
 616         while (!strbuf_getline(&sb, fp)) {
 617                 if (!sb.len)
 618                         break; /* End of header */
 619
 620                 /* Ignore indented folded lines */
 621                 if (*sb.buf == '\t' || *sb.buf == ' ')
 622                         continue;
 623
 624                 /* It's a header if it matches header_regex */
 625                 if (regexec(&regex, sb.buf, 0, NULL, 0)) {
 626                         ret = 0;
 627                         goto done;
 628                 }
 629         }
 630
 631 done:
 632         regfree(&regex);
 633         strbuf_release(&sb);
 634         return ret;
 635 }
 636
 637 /**
 638  * Attempts to detect the patch_format of the patches contained in `paths`,
 639  * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
 640  * detection fails.
 641  */
 642 static int detect_patch_format(const char **paths)
 643 {
 644         enum patch_format ret = PATCH_FORMAT_UNKNOWN;
 645         struct strbuf l1 = STRBUF_INIT;
 646         struct strbuf l2 = STRBUF_INIT;
 647         struct strbuf l3 = STRBUF_INIT;
 648         FILE *fp;
 649
 650         /*
 651          * We default to mbox format if input is from stdin and for directories
 652          */
 653         if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
 654                 return PATCH_FORMAT_MBOX;
 655
 656         /*
 657          * Otherwise, check the first few lines of the first patch, starting
 658          * from the first non-blank line, to try to detect its format.
 659          */
 660
 661         fp = xfopen(*paths, "r");
 662
 663         while (!strbuf_getline(&l1, fp)) {
 664                 if (l1.len)
 665                         break;
 666         }
 667
 668         if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
 669                 ret = PATCH_FORMAT_MBOX;
 670                 goto done;
 671         }
 672
 673         if (starts_with(l1.buf, "# This series applies on GIT commit")) {
 674                 ret = PATCH_FORMAT_STGIT_SERIES;
 675                 goto done;
 676         }
 677
 678         if (!strcmp(l1.buf, "# HG changeset patch")) {
 679                 ret = PATCH_FORMAT_HG;
 680                 goto done;
 681         }
 682
 683         strbuf_reset(&l2);
 684         strbuf_getline(&l2, fp);
 685         strbuf_reset(&l3);
 686         strbuf_getline(&l3, fp);
 687
 688         /*
 689          * If the second line is empty and the third is a From, Author or Date
 690          * entry, this is likely an StGit patch.
 691          */
 692         if (l1.len && !l2.len &&
 693                 (starts_with(l3.buf, "From:") ||
 694                  starts_with(l3.buf, "Author:") ||
 695                  starts_with(l3.buf, "Date:"))) {
 696                 ret = PATCH_FORMAT_STGIT;
 697                 goto done;
 698         }
 699
 700         if (l1.len && is_mail(fp)) {
 701                 ret = PATCH_FORMAT_MBOX;
 702                 goto done;
 703         }
 704
 705 done:
 706         fclose(fp);
 707         strbuf_release(&l1);
 708         return ret;
 709 }
 710
 711 /**
 712  * Splits out individual email patches from `paths`, where each path is either
 713  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
 714  */
 715 static int split_mail_mbox(struct am_state *state, const char **paths, int keep_cr)
 716 {
 717         struct child_process cp = CHILD_PROCESS_INIT;
 718         struct strbuf last = STRBUF_INIT;
 719
 720         cp.git_cmd = 1;
 721         argv_array_push(&cp.args, "mailsplit");
 722         argv_array_pushf(&cp.args, "-d%d", state->prec);
 723         argv_array_pushf(&cp.args, "-o%s", state->dir);
 724         argv_array_push(&cp.args, "-b");
 725         if (keep_cr)
 726                 argv_array_push(&cp.args, "--keep-cr");
 727         argv_array_push(&cp.args, "--");
 728         argv_array_pushv(&cp.args, paths);
 729
 730         if (capture_command(&cp, &last, 8))
 731                 return -1;
 732
 733         state->cur = 1;
 734         state->last = strtol(last.buf, NULL, 10);
 735
 736         return 0;
 737 }
 738
 739 /**
 740  * Callback signature for split_mail_conv(). The foreign patch should be
 741  * read from `in`, and the converted patch (in RFC2822 mail format) should be
 742  * written to `out`. Return 0 on success, or -1 on failure.
 743  */
 744 typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
 745
 746 /**
 747  * Calls `fn` for each file in `paths` to convert the foreign patch to the
 748  * RFC2822 mail format suitable for parsing with git-mailinfo.
 749  *
 750  * Returns 0 on success, -1 on failure.
 751  */
 752 static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
 753                         const char **paths, int keep_cr)
 754 {
 755         static const char *stdin_only[] = {"-", NULL};
 756         int i;
 757
 758         if (!*paths)
 759                 paths = stdin_only;
 760
 761         for (i = 0; *paths; paths++, i++) {
 762                 FILE *in, *out;
 763                 const char *mail;
 764                 int ret;
 765
 766                 if (!strcmp(*paths, "-"))
 767                         in = stdin;
 768                 else
 769                         in = fopen(*paths, "r");
 770
 771                 if (!in)
 772                         return error(_("could not open '%s' for reading: %s"),
 773                                         *paths, strerror(errno));
 774
 775                 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 776
 777                 out = fopen(mail, "w");
 778                 if (!out)
 779                         return error(_("could not open '%s' for writing: %s"),
 780                                         mail, strerror(errno));
 781
 782                 ret = fn(out, in, keep_cr);
 783
 784                 fclose(out);
 785                 fclose(in);
 786
 787                 if (ret)
 788                         return error(_("could not parse patch '%s'"), *paths);
 789         }
 790
 791         state->cur = 1;
 792         state->last = i;
 793         return 0;
 794 }
 795
 796 /**
 797  * A split_mail_conv() callback that converts an StGit patch to an RFC2822
 798  * message suitable for parsing with git-mailinfo.
 799  */
 800 static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 801 {
 802         struct strbuf sb = STRBUF_INIT;
 803         int subject_printed = 0;
 804
 805         while (!strbuf_getline_lf(&sb, in)) {
 806                 const char *str;
 807
 808                 if (str_isspace(sb.buf))
 809                         continue;
 810                 else if (skip_prefix(sb.buf, "Author:", &str))
 811                         fprintf(out, "From:%s\n", str);
 812                 else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
 813                         fprintf(out, "%s\n", sb.buf);
 814                 else if (!subject_printed) {
 815                         fprintf(out, "Subject: %s\n", sb.buf);
 816                         subject_printed = 1;
 817                 } else {
 818                         fprintf(out, "\n%s\n", sb.buf);
 819                         break;
 820                 }
 821         }
 822
 823         strbuf_reset(&sb);
 824         while (strbuf_fread(&sb, 8192, in) > 0) {
 825                 fwrite(sb.buf, 1, sb.len, out);
 826                 strbuf_reset(&sb);
 827         }
 828
 829         strbuf_release(&sb);
 830         return 0;
 831 }
 832
 833 /**
 834  * This function only supports a single StGit series file in `paths`.
 835  *
 836  * Given an StGit series file, converts the StGit patches in the series into
 837  * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
 838  * the state directory.
 839  *
 840  * Returns 0 on success, -1 on failure.
 841  */
 842 static int split_mail_stgit_series(struct am_state *state, const char **paths,
 843                                         int keep_cr)
 844 {
 845         const char *series_dir;
 846         char *series_dir_buf;
 847         FILE *fp;
 848         struct argv_array patches = ARGV_ARRAY_INIT;
 849         struct strbuf sb = STRBUF_INIT;
 850         int ret;
 851
 852         if (!paths[0] || paths[1])
 853                 return error(_("Only one StGIT patch series can be applied at once"));
 854
 855         series_dir_buf = xstrdup(*paths);
 856         series_dir = dirname(series_dir_buf);
 857
 858         fp = fopen(*paths, "r");
 859         if (!fp)
 860                 return error(_("could not open '%s' for reading: %s"), *paths,
 861                                 strerror(errno));
 862
 863         while (!strbuf_getline_lf(&sb, fp)) {
 864                 if (*sb.buf == '#')
 865                         continue; /* skip comment lines */
 866
 867                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
 868         }
 869
 870         fclose(fp);
 871         strbuf_release(&sb);
 872         free(series_dir_buf);
 873
 874         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
 875
 876         argv_array_clear(&patches);
 877         return ret;
 878 }
 879
 880 /**
 881  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
 882  * message suitable for parsing with git-mailinfo.
 883  */
 884 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 885 {
 886         struct strbuf sb = STRBUF_INIT;
 887
 888         while (!strbuf_getline_lf(&sb, in)) {
 889                 const char *str;
 890
 891                 if (skip_prefix(sb.buf, "# User ", &str))
 892                         fprintf(out, "From: %s\n", str);
 893                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
 894                         unsigned long timestamp;
 895                         long tz, tz2;
 896                         char *end;
 897
 898                         errno = 0;
 899                         timestamp = strtoul(str, &end, 10);
 900                         if (errno)
 901                                 return error(_("invalid timestamp"));
 902
 903                         if (!skip_prefix(end, " ", &str))
 904                                 return error(_("invalid Date line"));
 905
 906                         errno = 0;
 907                         tz = strtol(str, &end, 10);
 908                         if (errno)
 909                                 return error(_("invalid timezone offset"));
 910
 911                         if (*end)
 912                                 return error(_("invalid Date line"));
 913
 914                         /*
 915                          * mercurial's timezone is in seconds west of UTC,
 916                          * however git's timezone is in hours + minutes east of
 917                          * UTC. Convert it.
 918                          */
 919                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
 920                         if (tz > 0)
 921                                 tz2 = -tz2;
 922
 923                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
 924                 } else if (starts_with(sb.buf, "# ")) {
 925                         continue;
 926                 } else {
 927                         fprintf(out, "\n%s\n", sb.buf);
 928                         break;
 929                 }
 930         }
 931
 932         strbuf_reset(&sb);
 933         while (strbuf_fread(&sb, 8192, in) > 0) {
 934                 fwrite(sb.buf, 1, sb.len, out);
 935                 strbuf_reset(&sb);
 936         }
 937
 938         strbuf_release(&sb);
 939         return 0;
 940 }
 941
 942 /**
 943  * Splits a list of files/directories into individual email patches. Each path
 944  * in `paths` must be a file/directory that is formatted according to
 945  * `patch_format`.
 946  *
 947  * Once split out, the individual email patches will be stored in the state
 948  * directory, with each patch's filename being its index, padded to state->prec
 949  * digits.
 950  *
 951  * state->cur will be set to the index of the first mail, and state->last will
 952  * be set to the index of the last mail.
 953  *
 954  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
 955  * to disable this behavior, -1 to use the default configured setting.
 956  *
 957  * Returns 0 on success, -1 on failure.
 958  */
 959 static int split_mail(struct am_state *state, enum patch_format patch_format,
 960                         const char **paths, int keep_cr)
 961 {
 962         if (keep_cr < 0) {
 963                 keep_cr = 0;
 964                 git_config_get_bool("am.keepcr", &keep_cr);
 965         }
 966
 967         switch (patch_format) {
 968         case PATCH_FORMAT_MBOX:
 969                 return split_mail_mbox(state, paths, keep_cr);
 970         case PATCH_FORMAT_STGIT:
 971                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 972         case PATCH_FORMAT_STGIT_SERIES:
 973                 return split_mail_stgit_series(state, paths, keep_cr);
 974         case PATCH_FORMAT_HG:
 975                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
 976         default:
 977                 die("BUG: invalid patch_format");
 978         }
 979         return -1;
 980 }
 981
 982 /**
 983  * Setup a new am session for applying patches
 984  */
 985 static void am_setup(struct am_state *state, enum patch_format patch_format,
 986                         const char **paths, int keep_cr)
 987 {
 988         unsigned char curr_head[GIT_SHA1_RAWSZ];
 989         const char *str;
 990         struct strbuf sb = STRBUF_INIT;
 991
 992         if (!patch_format)
 993                 patch_format = detect_patch_format(paths);
 994
 995         if (!patch_format) {
 996                 fprintf_ln(stderr, _("Patch format detection failed."));
 997                 exit(128);
 998         }
 999
1000         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
1001                 die_errno(_("failed to create directory '%s'"), state->dir);
1002
1003         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
1004                 am_destroy(state);
1005                 die(_("Failed to split patches."));
1006         }
1007
1008         if (state->rebasing)
1009                 state->threeway = 1;
1010
1011         write_state_bool(state, "threeway", state->threeway);
1012         write_state_bool(state, "quiet", state->quiet);
1013         write_state_bool(state, "sign", state->signoff);
1014         write_state_bool(state, "utf8", state->utf8);
1015
1016         switch (state->keep) {
1017         case KEEP_FALSE:
1018                 str = "f";
1019                 break;
1020         case KEEP_TRUE:
1021                 str = "t";
1022                 break;
1023         case KEEP_NON_PATCH:
1024                 str = "b";
1025                 break;
1026         default:
1027                 die("BUG: invalid value for state->keep");
1028         }
1029
1030         write_state_text(state, "keep", str);
1031         write_state_bool(state, "messageid", state->message_id);
1032
1033         switch (state->scissors) {
1034         case SCISSORS_UNSET:
1035                 str = "";
1036                 break;
1037         case SCISSORS_FALSE:
1038                 str = "f";
1039                 break;
1040         case SCISSORS_TRUE:
1041                 str = "t";
1042                 break;
1043         default:
1044                 die("BUG: invalid value for state->scissors");
1045         }
1046         write_state_text(state, "scissors", str);
1047
1048         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1049         write_state_text(state, "apply-opt", sb.buf);
1050
1051         if (state->rebasing)
1052                 write_state_text(state, "rebasing", "");
1053         else
1054                 write_state_text(state, "applying", "");
1055
1056         if (!get_sha1("HEAD", curr_head)) {
1057                 write_state_text(state, "abort-safety", sha1_to_hex(curr_head));
1058                 if (!state->rebasing)
1059                         update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
1060                                         UPDATE_REFS_DIE_ON_ERR);
1061         } else {
1062                 write_state_text(state, "abort-safety", "");
1063                 if (!state->rebasing)
1064                         delete_ref("ORIG_HEAD", NULL, 0);
1065         }
1066
1067         /*
1068          * NOTE: Since the "next" and "last" files determine if an am_state
1069          * session is in progress, they should be written last.
1070          */
1071
1072         write_state_count(state, "next", state->cur);
1073         write_state_count(state, "last", state->last);
1074
1075         strbuf_release(&sb);
1076 }
1077
1078 /**
1079  * Increments the patch pointer, and cleans am_state for the application of the
1080  * next patch.
1081  */
1082 static void am_next(struct am_state *state)
1083 {
1084         unsigned char head[GIT_SHA1_RAWSZ];
1085
1086         free(state->author_name);
1087         state->author_name = NULL;
1088
1089         free(state->author_email);
1090         state->author_email = NULL;
1091
1092         free(state->author_date);
1093         state->author_date = NULL;
1094
1095         free(state->msg);
1096         state->msg = NULL;
1097         state->msg_len = 0;
1098
1099         unlink(am_path(state, "author-script"));
1100         unlink(am_path(state, "final-commit"));
1101
1102         hashclr(state->orig_commit);
1103         unlink(am_path(state, "original-commit"));
1104
1105         if (!get_sha1("HEAD", head))
1106                 write_state_text(state, "abort-safety", sha1_to_hex(head));
1107         else
1108                 write_state_text(state, "abort-safety", "");
1109
1110         state->cur++;
1111         write_state_count(state, "next", state->cur);
1112 }
1113
1114 /**
1115  * Returns the filename of the current patch email.
1116  */
1117 static const char *msgnum(const struct am_state *state)
1118 {
1119         static struct strbuf sb = STRBUF_INIT;
1120
1121         strbuf_reset(&sb);
1122         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1123
1124         return sb.buf;
1125 }
1126
1127 /**
1128  * Refresh and write index.
1129  */
1130 static void refresh_and_write_cache(void)
1131 {
1132         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1133
1134         hold_locked_index(lock_file, 1);
1135         refresh_cache(REFRESH_QUIET);
1136         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1137                 die(_("unable to write index file"));
1138 }
1139
1140 /**
1141  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1142  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1143  * strbuf is provided, the space-separated list of files that differ will be
1144  * appended to it.
1145  */
1146 static int index_has_changes(struct strbuf *sb)
1147 {
1148         unsigned char head[GIT_SHA1_RAWSZ];
1149         int i;
1150
1151         if (!get_sha1_tree("HEAD", head)) {
1152                 struct diff_options opt;
1153
1154                 diff_setup(&opt);
1155                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1156                 if (!sb)
1157                         DIFF_OPT_SET(&opt, QUICK);
1158                 do_diff_cache(head, &opt);
1159                 diffcore_std(&opt);
1160                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1161                         if (i)
1162                                 strbuf_addch(sb, ' ');
1163                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1164                 }
1165                 diff_flush(&opt);
1166                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1167         } else {
1168                 for (i = 0; sb && i < active_nr; i++) {
1169                         if (i)
1170                                 strbuf_addch(sb, ' ');
1171                         strbuf_addstr(sb, active_cache[i]->name);
1172                 }
1173                 return !!active_nr;
1174         }
1175 }
1176
1177 /**
1178  * Dies with a user-friendly message on how to proceed after resolving the
1179  * problem. This message can be overridden with state->resolvemsg.
1180  */
1181 static void NORETURN die_user_resolve(const struct am_state *state)
1182 {
1183         if (state->resolvemsg) {
1184                 printf_ln("%s", state->resolvemsg);
1185         } else {
1186                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1187
1188                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1189                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1190                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1191         }
1192
1193         exit(128);
1194 }
1195
1196 static void am_signoff(struct strbuf *sb)
1197 {
1198         char *cp;
1199         struct strbuf mine = STRBUF_INIT;
1200
1201         /* Does it end with our own sign-off? */
1202         strbuf_addf(&mine, "\n%s%s\n",
1203                     sign_off_header,
1204                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1205                              getenv("GIT_COMMITTER_EMAIL")));
1206         if (mine.len < sb->len &&
1207             !strcmp(mine.buf, sb->buf + sb->len - mine.len))
1208                 goto exit; /* no need to duplicate */
1209
1210         /* Does it have any Signed-off-by: in the text */
1211         for (cp = sb->buf;
1212              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1213              cp = strchr(cp, '\n')) {
1214                 if (sb->buf == cp || cp[-1] == '\n')
1215                         break;
1216         }
1217
1218         strbuf_addstr(sb, mine.buf + !!cp);
1219 exit:
1220         strbuf_release(&mine);
1221 }
1222
1223 /**
1224  * Appends signoff to the "msg" field of the am_state.
1225  */
1226 static void am_append_signoff(struct am_state *state)
1227 {
1228         struct strbuf sb = STRBUF_INIT;
1229
1230         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1231         am_signoff(&sb);
1232         state->msg = strbuf_detach(&sb, &state->msg_len);
1233 }
1234
1235 /**
1236  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1237  * state->msg will be set to the patch message. state->author_name,
1238  * state->author_email and state->author_date will be set to the patch author's
1239  * name, email and date respectively. The patch body will be written to the
1240  * state directory's "patch" file.
1241  *
1242  * Returns 1 if the patch should be skipped, 0 otherwise.
1243  */
1244 static int parse_mail(struct am_state *state, const char *mail)
1245 {
1246         FILE *fp;
1247         struct strbuf sb = STRBUF_INIT;
1248         struct strbuf msg = STRBUF_INIT;
1249         struct strbuf author_name = STRBUF_INIT;
1250         struct strbuf author_date = STRBUF_INIT;
1251         struct strbuf author_email = STRBUF_INIT;
1252         int ret = 0;
1253         struct mailinfo mi;
1254
1255         setup_mailinfo(&mi);
1256
1257         if (state->utf8)
1258                 mi.metainfo_charset = get_commit_output_encoding();
1259         else
1260                 mi.metainfo_charset = NULL;
1261
1262         switch (state->keep) {
1263         case KEEP_FALSE:
1264                 break;
1265         case KEEP_TRUE:
1266                 mi.keep_subject = 1;
1267                 break;
1268         case KEEP_NON_PATCH:
1269                 mi.keep_non_patch_brackets_in_subject = 1;
1270                 break;
1271         default:
1272                 die("BUG: invalid value for state->keep");
1273         }
1274
1275         if (state->message_id)
1276                 mi.add_message_id = 1;
1277
1278         switch (state->scissors) {
1279         case SCISSORS_UNSET:
1280                 break;
1281         case SCISSORS_FALSE:
1282                 mi.use_scissors = 0;
1283                 break;
1284         case SCISSORS_TRUE:
1285                 mi.use_scissors = 1;
1286                 break;
1287         default:
1288                 die("BUG: invalid value for state->scissors");
1289         }
1290
1291         mi.input = fopen(mail, "r");
1292         if (!mi.input)
1293                 die("could not open input");
1294         mi.output = fopen(am_path(state, "info"), "w");
1295         if (!mi.output)
1296                 die("could not open output 'info'");
1297         if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
1298                 die("could not parse patch");
1299
1300         fclose(mi.input);
1301         fclose(mi.output);
1302
1303         /* Extract message and author information */
1304         fp = xfopen(am_path(state, "info"), "r");
1305         while (!strbuf_getline_lf(&sb, fp)) {
1306                 const char *x;
1307
1308                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1309                         if (msg.len)
1310                                 strbuf_addch(&msg, '\n');
1311                         strbuf_addstr(&msg, x);
1312                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1313                         strbuf_addstr(&author_name, x);
1314                 else if (skip_prefix(sb.buf, "Email: ", &x))
1315                         strbuf_addstr(&author_email, x);
1316                 else if (skip_prefix(sb.buf, "Date: ", &x))
1317                         strbuf_addstr(&author_date, x);
1318         }
1319         fclose(fp);
1320
1321         /* Skip pine's internal folder data */
1322         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1323                 ret = 1;
1324                 goto finish;
1325         }
1326
1327         if (is_empty_file(am_path(state, "patch"))) {
1328                 printf_ln(_("Patch is empty. Was it split wrong?"));
1329                 die_user_resolve(state);
1330         }
1331
1332         strbuf_addstr(&msg, "\n\n");
1333         strbuf_addbuf(&msg, &mi.log_message);
1334         strbuf_stripspace(&msg, 0);
1335
1336         if (state->signoff)
1337                 am_signoff(&msg);
1338
1339         assert(!state->author_name);
1340         state->author_name = strbuf_detach(&author_name, NULL);
1341
1342         assert(!state->author_email);
1343         state->author_email = strbuf_detach(&author_email, NULL);
1344
1345         assert(!state->author_date);
1346         state->author_date = strbuf_detach(&author_date, NULL);
1347
1348         assert(!state->msg);
1349         state->msg = strbuf_detach(&msg, &state->msg_len);
1350
1351 finish:
1352         strbuf_release(&msg);
1353         strbuf_release(&author_date);
1354         strbuf_release(&author_email);
1355         strbuf_release(&author_name);
1356         strbuf_release(&sb);
1357         clear_mailinfo(&mi);
1358         return ret;
1359 }
1360
1361 /**
1362  * Sets commit_id to the commit hash where the mail was generated from.
1363  * Returns 0 on success, -1 on failure.
1364  */
1365 static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
1366 {
1367         struct strbuf sb = STRBUF_INIT;
1368         FILE *fp = xfopen(mail, "r");
1369         const char *x;
1370
1371         if (strbuf_getline_lf(&sb, fp))
1372                 return -1;
1373
1374         if (!skip_prefix(sb.buf, "From ", &x))
1375                 return -1;
1376
1377         if (get_sha1_hex(x, commit_id) < 0)
1378                 return -1;
1379
1380         strbuf_release(&sb);
1381         fclose(fp);
1382         return 0;
1383 }
1384
1385 /**
1386  * Sets state->msg, state->author_name, state->author_email, state->author_date
1387  * to the commit's respective info.
1388  */
1389 static void get_commit_info(struct am_state *state, struct commit *commit)
1390 {
1391         const char *buffer, *ident_line, *author_date, *msg;
1392         size_t ident_len;
1393         struct ident_split ident_split;
1394         struct strbuf sb = STRBUF_INIT;
1395
1396         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1397
1398         ident_line = find_commit_header(buffer, "author", &ident_len);
1399
1400         if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
1401                 strbuf_add(&sb, ident_line, ident_len);
1402                 die(_("invalid ident line: %s"), sb.buf);
1403         }
1404
1405         assert(!state->author_name);
1406         if (ident_split.name_begin) {
1407                 strbuf_add(&sb, ident_split.name_begin,
1408                         ident_split.name_end - ident_split.name_begin);
1409                 state->author_name = strbuf_detach(&sb, NULL);
1410         } else
1411                 state->author_name = xstrdup("");
1412
1413         assert(!state->author_email);
1414         if (ident_split.mail_begin) {
1415                 strbuf_add(&sb, ident_split.mail_begin,
1416                         ident_split.mail_end - ident_split.mail_begin);
1417                 state->author_email = strbuf_detach(&sb, NULL);
1418         } else
1419                 state->author_email = xstrdup("");
1420
1421         author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
1422         strbuf_addstr(&sb, author_date);
1423         assert(!state->author_date);
1424         state->author_date = strbuf_detach(&sb, NULL);
1425
1426         assert(!state->msg);
1427         msg = strstr(buffer, "\n\n");
1428         if (!msg)
1429                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1430         state->msg = xstrdup(msg + 2);
1431         state->msg_len = strlen(state->msg);
1432 }
1433
1434 /**
1435  * Writes `commit` as a patch to the state directory's "patch" file.
1436  */
1437 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1438 {
1439         struct rev_info rev_info;
1440         FILE *fp;
1441
1442         fp = xfopen(am_path(state, "patch"), "w");
1443         init_revisions(&rev_info, NULL);
1444         rev_info.diff = 1;
1445         rev_info.abbrev = 0;
1446         rev_info.disable_stdin = 1;
1447         rev_info.show_root_diff = 1;
1448         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1449         rev_info.no_commit_id = 1;
1450         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1451         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1452         rev_info.diffopt.use_color = 0;
1453         rev_info.diffopt.file = fp;
1454         rev_info.diffopt.close_file = 1;
1455         add_pending_object(&rev_info, &commit->object, "");
1456         diff_setup_done(&rev_info.diffopt);
1457         log_tree_commit(&rev_info, commit);
1458 }
1459
1460 /**
1461  * Writes the diff of the index against HEAD as a patch to the state
1462  * directory's "patch" file.
1463  */
1464 static void write_index_patch(const struct am_state *state)
1465 {
1466         struct tree *tree;
1467         unsigned char head[GIT_SHA1_RAWSZ];
1468         struct rev_info rev_info;
1469         FILE *fp;
1470
1471         if (!get_sha1_tree("HEAD", head))
1472                 tree = lookup_tree(head);
1473         else
1474                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1475
1476         fp = xfopen(am_path(state, "patch"), "w");
1477         init_revisions(&rev_info, NULL);
1478         rev_info.diff = 1;
1479         rev_info.disable_stdin = 1;
1480         rev_info.no_commit_id = 1;
1481         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1482         rev_info.diffopt.use_color = 0;
1483         rev_info.diffopt.file = fp;
1484         rev_info.diffopt.close_file = 1;
1485         add_pending_object(&rev_info, &tree->object, "");
1486         diff_setup_done(&rev_info.diffopt);
1487         run_diff_index(&rev_info, 1);
1488 }
1489
1490 /**
1491  * Like parse_mail(), but parses the mail by looking up its commit ID
1492  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1493  * of patches.
1494  *
1495  * state->orig_commit will be set to the original commit ID.
1496  *
1497  * Will always return 0 as the patch should never be skipped.
1498  */
1499 static int parse_mail_rebase(struct am_state *state, const char *mail)
1500 {
1501         struct commit *commit;
1502         unsigned char commit_sha1[GIT_SHA1_RAWSZ];
1503
1504         if (get_mail_commit_sha1(commit_sha1, mail) < 0)
1505                 die(_("could not parse %s"), mail);
1506
1507         commit = lookup_commit_or_die(commit_sha1, mail);
1508
1509         get_commit_info(state, commit);
1510
1511         write_commit_patch(state, commit);
1512
1513         hashcpy(state->orig_commit, commit_sha1);
1514         write_state_text(state, "original-commit", sha1_to_hex(commit_sha1));
1515
1516         return 0;
1517 }
1518
1519 /**
1520  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1521  * `index_file` is not NULL, the patch will be applied to that index.
1522  */
1523 static int run_apply(const struct am_state *state, const char *index_file)
1524 {
1525         struct child_process cp = CHILD_PROCESS_INIT;
1526
1527         cp.git_cmd = 1;
1528
1529         if (index_file)
1530                 argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
1531
1532         /*
1533          * If we are allowed to fall back on 3-way merge, don't give false
1534          * errors during the initial attempt.
1535          */
1536         if (state->threeway && !index_file) {
1537                 cp.no_stdout = 1;
1538                 cp.no_stderr = 1;
1539         }
1540
1541         argv_array_push(&cp.args, "apply");
1542
1543         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1544
1545         if (index_file)
1546                 argv_array_push(&cp.args, "--cached");
1547         else
1548                 argv_array_push(&cp.args, "--index");
1549
1550         argv_array_push(&cp.args, am_path(state, "patch"));
1551
1552         if (run_command(&cp))
1553                 return -1;
1554
1555         /* Reload index as git-apply will have modified it. */
1556         discard_cache();
1557         read_cache_from(index_file ? index_file : get_index_file());
1558
1559         return 0;
1560 }
1561
1562 /**
1563  * Builds an index that contains just the blobs needed for a 3way merge.
1564  */
1565 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1566 {
1567         struct child_process cp = CHILD_PROCESS_INIT;
1568
1569         cp.git_cmd = 1;
1570         argv_array_push(&cp.args, "apply");
1571         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1572         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1573         argv_array_push(&cp.args, am_path(state, "patch"));
1574
1575         if (run_command(&cp))
1576                 return -1;
1577
1578         return 0;
1579 }
1580
1581 /**
1582  * Do the three-way merge using fake ancestor, his tree constructed
1583  * from the fake ancestor and the postimage of the patch, and our
1584  * state.
1585  */
1586 static int run_fallback_merge_recursive(const struct am_state *state,
1587                                         unsigned char *orig_tree,
1588                                         unsigned char *our_tree,
1589                                         unsigned char *his_tree)
1590 {
1591         struct child_process cp = CHILD_PROCESS_INIT;
1592         int status;
1593
1594         cp.git_cmd = 1;
1595
1596         argv_array_pushf(&cp.env_array, "GITHEAD_%s=%.*s",
1597                          sha1_to_hex(his_tree), linelen(state->msg), state->msg);
1598         if (state->quiet)
1599                 argv_array_push(&cp.env_array, "GIT_MERGE_VERBOSITY=0");
1600
1601         argv_array_push(&cp.args, "merge-recursive");
1602         argv_array_push(&cp.args, sha1_to_hex(orig_tree));
1603         argv_array_push(&cp.args, "--");
1604         argv_array_push(&cp.args, sha1_to_hex(our_tree));
1605         argv_array_push(&cp.args, sha1_to_hex(his_tree));
1606
1607         status = run_command(&cp) ? (-1) : 0;
1608         discard_cache();
1609         read_cache();
1610         return status;
1611 }
1612
1613 /**
1614  * Attempt a threeway merge, using index_path as the temporary index.
1615  */
1616 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1617 {
1618         unsigned char orig_tree[GIT_SHA1_RAWSZ], his_tree[GIT_SHA1_RAWSZ],
1619                       our_tree[GIT_SHA1_RAWSZ];
1620
1621         if (get_sha1("HEAD", our_tree) < 0)
1622                 hashcpy(our_tree, EMPTY_TREE_SHA1_BIN);
1623
1624         if (build_fake_ancestor(state, index_path))
1625                 return error("could not build fake ancestor");
1626
1627         discard_cache();
1628         read_cache_from(index_path);
1629
1630         if (write_index_as_tree(orig_tree, &the_index, index_path, 0, NULL))
1631                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1632
1633         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1634
1635         if (!state->quiet) {
1636                 /*
1637                  * List paths that needed 3-way fallback, so that the user can
1638                  * review them with extra care to spot mismerges.
1639                  */
1640                 struct rev_info rev_info;
1641                 const char *diff_filter_str = "--diff-filter=AM";
1642
1643                 init_revisions(&rev_info, NULL);
1644                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1645                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1646                 add_pending_sha1(&rev_info, "HEAD", our_tree, 0);
1647                 diff_setup_done(&rev_info.diffopt);
1648                 run_diff_index(&rev_info, 1);
1649         }
1650
1651         if (run_apply(state, index_path))
1652                 return error(_("Did you hand edit your patch?\n"
1653                                 "It does not apply to blobs recorded in its index."));
1654
1655         if (write_index_as_tree(his_tree, &the_index, index_path, 0, NULL))
1656                 return error("could not write tree");
1657
1658         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1659
1660         discard_cache();
1661         read_cache();
1662
1663         /*
1664          * This is not so wrong. Depending on which base we picked, orig_tree
1665          * may be wildly different from ours, but his_tree has the same set of
1666          * wildly different changes in parts the patch did not touch, so
1667          * recursive ends up canceling them, saying that we reverted all those
1668          * changes.
1669          */
1670
1671         if (run_fallback_merge_recursive(state, orig_tree, our_tree, his_tree)) {
1672                 rerere(state->allow_rerere_autoupdate);
1673                 return error(_("Failed to merge in the changes."));
1674         }
1675
1676         return 0;
1677 }
1678
1679 /**
1680  * Commits the current index with state->msg as the commit message and
1681  * state->author_name, state->author_email and state->author_date as the author
1682  * information.
1683  */
1684 static void do_commit(const struct am_state *state)
1685 {
1686         unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
1687                       commit[GIT_SHA1_RAWSZ];
1688         unsigned char *ptr;
1689         struct commit_list *parents = NULL;
1690         const char *reflog_msg, *author;
1691         struct strbuf sb = STRBUF_INIT;
1692
1693         if (run_hook_le(NULL, "pre-applypatch", NULL))
1694                 exit(1);
1695
1696         if (write_cache_as_tree(tree, 0, NULL))
1697                 die(_("git write-tree failed to write a tree"));
1698
1699         if (!get_sha1_commit("HEAD", parent)) {
1700                 ptr = parent;
1701                 commit_list_insert(lookup_commit(parent), &parents);
1702         } else {
1703                 ptr = NULL;
1704                 say(state, stderr, _("applying to an empty history"));
1705         }
1706
1707         author = fmt_ident(state->author_name, state->author_email,
1708                         state->ignore_date ? NULL : state->author_date,
1709                         IDENT_STRICT);
1710
1711         if (state->committer_date_is_author_date)
1712                 setenv("GIT_COMMITTER_DATE",
1713                         state->ignore_date ? "" : state->author_date, 1);
1714
1715         if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
1716                                 author, state->sign_commit))
1717                 die(_("failed to write commit object"));
1718
1719         reflog_msg = getenv("GIT_REFLOG_ACTION");
1720         if (!reflog_msg)
1721                 reflog_msg = "am";
1722
1723         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1724                         state->msg);
1725
1726         update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
1727
1728         if (state->rebasing) {
1729                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1730
1731                 assert(!is_null_sha1(state->orig_commit));
1732                 fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
1733                 fprintf(fp, "%s\n", sha1_to_hex(commit));
1734                 fclose(fp);
1735         }
1736
1737         run_hook_le(NULL, "post-applypatch", NULL);
1738
1739         strbuf_release(&sb);
1740 }
1741
1742 /**
1743  * Validates the am_state for resuming -- the "msg" and authorship fields must
1744  * be filled up.
1745  */
1746 static void validate_resume_state(const struct am_state *state)
1747 {
1748         if (!state->msg)
1749                 die(_("cannot resume: %s does not exist."),
1750                         am_path(state, "final-commit"));
1751
1752         if (!state->author_name || !state->author_email || !state->author_date)
1753                 die(_("cannot resume: %s does not exist."),
1754                         am_path(state, "author-script"));
1755 }
1756
1757 /**
1758  * Interactively prompt the user on whether the current patch should be
1759  * applied.
1760  *
1761  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1762  * skip it.
1763  */
1764 static int do_interactive(struct am_state *state)
1765 {
1766         assert(state->msg);
1767
1768         if (!isatty(0))
1769                 die(_("cannot be interactive without stdin connected to a terminal."));
1770
1771         for (;;) {
1772                 const char *reply;
1773
1774                 puts(_("Commit Body is:"));
1775                 puts("--------------------------");
1776                 printf("%s", state->msg);
1777                 puts("--------------------------");
1778
1779                 /*
1780                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1781                  * in your translation. The program will only accept English
1782                  * input at this point.
1783                  */
1784                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1785
1786                 if (!reply) {
1787                         continue;
1788                 } else if (*reply == 'y' || *reply == 'Y') {
1789                         return 0;
1790                 } else if (*reply == 'a' || *reply == 'A') {
1791                         state->interactive = 0;
1792                         return 0;
1793                 } else if (*reply == 'n' || *reply == 'N') {
1794                         return 1;
1795                 } else if (*reply == 'e' || *reply == 'E') {
1796                         struct strbuf msg = STRBUF_INIT;
1797
1798                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1799                                 free(state->msg);
1800                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1801                         }
1802                         strbuf_release(&msg);
1803                 } else if (*reply == 'v' || *reply == 'V') {
1804                         const char *pager = git_pager(1);
1805                         struct child_process cp = CHILD_PROCESS_INIT;
1806
1807                         if (!pager)
1808                                 pager = "cat";
1809                         prepare_pager_args(&cp, pager);
1810                         argv_array_push(&cp.args, am_path(state, "patch"));
1811                         run_command(&cp);
1812                 }
1813         }
1814 }
1815
1816 /**
1817  * Applies all queued mail.
1818  *
1819  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1820  * well as the state directory's "patch" file is used as-is for applying the
1821  * patch and committing it.
1822  */
1823 static void am_run(struct am_state *state, int resume)
1824 {
1825         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1826         struct strbuf sb = STRBUF_INIT;
1827
1828         unlink(am_path(state, "dirtyindex"));
1829
1830         refresh_and_write_cache();
1831
1832         if (index_has_changes(&sb)) {
1833                 write_state_bool(state, "dirtyindex", 1);
1834                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1835         }
1836
1837         strbuf_release(&sb);
1838
1839         while (state->cur <= state->last) {
1840                 const char *mail = am_path(state, msgnum(state));
1841                 int apply_status;
1842
1843                 if (!file_exists(mail))
1844                         goto next;
1845
1846                 if (resume) {
1847                         validate_resume_state(state);
1848                 } else {
1849                         int skip;
1850
1851                         if (state->rebasing)
1852                                 skip = parse_mail_rebase(state, mail);
1853                         else
1854                                 skip = parse_mail(state, mail);
1855
1856                         if (skip)
1857                                 goto next; /* mail should be skipped */
1858
1859                         write_author_script(state);
1860                         write_commit_msg(state);
1861                 }
1862
1863                 if (state->interactive && do_interactive(state))
1864                         goto next;
1865
1866                 if (run_applypatch_msg_hook(state))
1867                         exit(1);
1868
1869                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1870
1871                 apply_status = run_apply(state, NULL);
1872
1873                 if (apply_status && state->threeway) {
1874                         struct strbuf sb = STRBUF_INIT;
1875
1876                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1877                         apply_status = fall_back_threeway(state, sb.buf);
1878                         strbuf_release(&sb);
1879
1880                         /*
1881                          * Applying the patch to an earlier tree and merging
1882                          * the result may have produced the same tree as ours.
1883                          */
1884                         if (!apply_status && !index_has_changes(NULL)) {
1885                                 say(state, stdout, _("No changes -- Patch already applied."));
1886                                 goto next;
1887                         }
1888                 }
1889
1890                 if (apply_status) {
1891                         int advice_amworkdir = 1;
1892
1893                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1894                                 linelen(state->msg), state->msg);
1895
1896                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1897
1898                         if (advice_amworkdir)
1899                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1900                                                 am_path(state, "patch"));
1901
1902                         die_user_resolve(state);
1903                 }
1904
1905                 do_commit(state);
1906
1907 next:
1908                 am_next(state);
1909
1910                 if (resume)
1911                         am_load(state);
1912                 resume = 0;
1913         }
1914
1915         if (!is_empty_file(am_path(state, "rewritten"))) {
1916                 assert(state->rebasing);
1917                 copy_notes_for_rebase(state);
1918                 run_post_rewrite_hook(state);
1919         }
1920
1921         /*
1922          * In rebasing mode, it's up to the caller to take care of
1923          * housekeeping.
1924          */
1925         if (!state->rebasing) {
1926                 am_destroy(state);
1927                 close_all_packs();
1928                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1929         }
1930 }
1931
1932 /**
1933  * Resume the current am session after patch application failure. The user did
1934  * all the hard work, and we do not have to do any patch application. Just
1935  * trust and commit what the user has in the index and working tree.
1936  */
1937 static void am_resolve(struct am_state *state)
1938 {
1939         validate_resume_state(state);
1940
1941         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1942
1943         if (!index_has_changes(NULL)) {
1944                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1945                         "If there is nothing left to stage, chances are that something else\n"
1946                         "already introduced the same changes; you might want to skip this patch."));
1947                 die_user_resolve(state);
1948         }
1949
1950         if (unmerged_cache()) {
1951                 printf_ln(_("You still have unmerged paths in your index.\n"
1952                         "Did you forget to use 'git add'?"));
1953                 die_user_resolve(state);
1954         }
1955
1956         if (state->interactive) {
1957                 write_index_patch(state);
1958                 if (do_interactive(state))
1959                         goto next;
1960         }
1961
1962         rerere(0);
1963
1964         do_commit(state);
1965
1966 next:
1967         am_next(state);
1968         am_load(state);
1969         am_run(state, 0);
1970 }
1971
1972 /**
1973  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1974  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1975  * failure.
1976  */
1977 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1978 {
1979         struct lock_file *lock_file;
1980         struct unpack_trees_options opts;
1981         struct tree_desc t[2];
1982
1983         if (parse_tree(head) || parse_tree(remote))
1984                 return -1;
1985
1986         lock_file = xcalloc(1, sizeof(struct lock_file));
1987         hold_locked_index(lock_file, 1);
1988
1989         refresh_cache(REFRESH_QUIET);
1990
1991         memset(&opts, 0, sizeof(opts));
1992         opts.head_idx = 1;
1993         opts.src_index = &the_index;
1994         opts.dst_index = &the_index;
1995         opts.update = 1;
1996         opts.merge = 1;
1997         opts.reset = reset;
1998         opts.fn = twoway_merge;
1999         init_tree_desc(&t[0], head->buffer, head->size);
2000         init_tree_desc(&t[1], remote->buffer, remote->size);
2001
2002         if (unpack_trees(2, t, &opts)) {
2003                 rollback_lock_file(lock_file);
2004                 return -1;
2005         }
2006
2007         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2008                 die(_("unable to write new index file"));
2009
2010         return 0;
2011 }
2012
2013 /**
2014  * Merges a tree into the index. The index's stat info will take precedence
2015  * over the merged tree's. Returns 0 on success, -1 on failure.
2016  */
2017 static int merge_tree(struct tree *tree)
2018 {
2019         struct lock_file *lock_file;
2020         struct unpack_trees_options opts;
2021         struct tree_desc t[1];
2022
2023         if (parse_tree(tree))
2024                 return -1;
2025
2026         lock_file = xcalloc(1, sizeof(struct lock_file));
2027         hold_locked_index(lock_file, 1);
2028
2029         memset(&opts, 0, sizeof(opts));
2030         opts.head_idx = 1;
2031         opts.src_index = &the_index;
2032         opts.dst_index = &the_index;
2033         opts.merge = 1;
2034         opts.fn = oneway_merge;
2035         init_tree_desc(&t[0], tree->buffer, tree->size);
2036
2037         if (unpack_trees(1, t, &opts)) {
2038                 rollback_lock_file(lock_file);
2039                 return -1;
2040         }
2041
2042         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2043                 die(_("unable to write new index file"));
2044
2045         return 0;
2046 }
2047
2048 /**
2049  * Clean the index without touching entries that are not modified between
2050  * `head` and `remote`.
2051  */
2052 static int clean_index(const unsigned char *head, const unsigned char *remote)
2053 {
2054         struct tree *head_tree, *remote_tree, *index_tree;
2055         unsigned char index[GIT_SHA1_RAWSZ];
2056
2057         head_tree = parse_tree_indirect(head);
2058         if (!head_tree)
2059                 return error(_("Could not parse object '%s'."), sha1_to_hex(head));
2060
2061         remote_tree = parse_tree_indirect(remote);
2062         if (!remote_tree)
2063                 return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
2064
2065         read_cache_unmerged();
2066
2067         if (fast_forward_to(head_tree, head_tree, 1))
2068                 return -1;
2069
2070         if (write_cache_as_tree(index, 0, NULL))
2071                 return -1;
2072
2073         index_tree = parse_tree_indirect(index);
2074         if (!index_tree)
2075                 return error(_("Could not parse object '%s'."), sha1_to_hex(index));
2076
2077         if (fast_forward_to(index_tree, remote_tree, 0))
2078                 return -1;
2079
2080         if (merge_tree(remote_tree))
2081                 return -1;
2082
2083         remove_branch_state();
2084
2085         return 0;
2086 }
2087
2088 /**
2089  * Resets rerere's merge resolution metadata.
2090  */
2091 static void am_rerere_clear(void)
2092 {
2093         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2094         rerere_clear(&merge_rr);
2095         string_list_clear(&merge_rr, 1);
2096 }
2097
2098 /**
2099  * Resume the current am session by skipping the current patch.
2100  */
2101 static void am_skip(struct am_state *state)
2102 {
2103         unsigned char head[GIT_SHA1_RAWSZ];
2104
2105         am_rerere_clear();
2106
2107         if (get_sha1("HEAD", head))
2108                 hashcpy(head, EMPTY_TREE_SHA1_BIN);
2109
2110         if (clean_index(head, head))
2111                 die(_("failed to clean index"));
2112
2113         am_next(state);
2114         am_load(state);
2115         am_run(state, 0);
2116 }
2117
2118 /**
2119  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2120  *
2121  * It is not safe to reset HEAD when:
2122  * 1. git-am previously failed because the index was dirty.
2123  * 2. HEAD has moved since git-am previously failed.
2124  */
2125 static int safe_to_abort(const struct am_state *state)
2126 {
2127         struct strbuf sb = STRBUF_INIT;
2128         unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
2129
2130         if (file_exists(am_path(state, "dirtyindex")))
2131                 return 0;
2132
2133         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2134                 if (get_sha1_hex(sb.buf, abort_safety))
2135                         die(_("could not parse %s"), am_path(state, "abort_safety"));
2136         } else
2137                 hashclr(abort_safety);
2138
2139         if (get_sha1("HEAD", head))
2140                 hashclr(head);
2141
2142         if (!hashcmp(head, abort_safety))
2143                 return 1;
2144
2145         error(_("You seem to have moved HEAD since the last 'am' failure.\n"
2146                 "Not rewinding to ORIG_HEAD"));
2147
2148         return 0;
2149 }
2150
2151 /**
2152  * Aborts the current am session if it is safe to do so.
2153  */
2154 static void am_abort(struct am_state *state)
2155 {
2156         unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
2157         int has_curr_head, has_orig_head;
2158         char *curr_branch;
2159
2160         if (!safe_to_abort(state)) {
2161                 am_destroy(state);
2162                 return;
2163         }
2164
2165         am_rerere_clear();
2166
2167         curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
2168         has_curr_head = !is_null_sha1(curr_head);
2169         if (!has_curr_head)
2170                 hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
2171
2172         has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
2173         if (!has_orig_head)
2174                 hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
2175
2176         clean_index(curr_head, orig_head);
2177
2178         if (has_orig_head)
2179                 update_ref("am --abort", "HEAD", orig_head,
2180                                 has_curr_head ? curr_head : NULL, 0,
2181                                 UPDATE_REFS_DIE_ON_ERR);
2182         else if (curr_branch)
2183                 delete_ref(curr_branch, NULL, REF_NODEREF);
2184
2185         free(curr_branch);
2186         am_destroy(state);
2187 }
2188
2189 /**
2190  * parse_options() callback that validates and sets opt->value to the
2191  * PATCH_FORMAT_* enum value corresponding to `arg`.
2192  */
2193 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2194 {
2195         int *opt_value = opt->value;
2196
2197         if (!strcmp(arg, "mbox"))
2198                 *opt_value = PATCH_FORMAT_MBOX;
2199         else if (!strcmp(arg, "stgit"))
2200                 *opt_value = PATCH_FORMAT_STGIT;
2201         else if (!strcmp(arg, "stgit-series"))
2202                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2203         else if (!strcmp(arg, "hg"))
2204                 *opt_value = PATCH_FORMAT_HG;
2205         else
2206                 return error(_("Invalid value for --patch-format: %s"), arg);
2207         return 0;
2208 }
2209
2210 enum resume_mode {
2211         RESUME_FALSE = 0,
2212         RESUME_APPLY,
2213         RESUME_RESOLVED,
2214         RESUME_SKIP,
2215         RESUME_ABORT
2216 };
2217
2218 static int git_am_config(const char *k, const char *v, void *cb)
2219 {
2220         int status;
2221
2222         status = git_gpg_config(k, v, NULL);
2223         if (status)
2224                 return status;
2225
2226         return git_default_config(k, v, NULL);
2227 }
2228
2229 int cmd_am(int argc, const char **argv, const char *prefix)
2230 {
2231         struct am_state state;
2232         int binary = -1;
2233         int keep_cr = -1;
2234         int patch_format = PATCH_FORMAT_UNKNOWN;
2235         enum resume_mode resume = RESUME_FALSE;
2236         int in_progress;
2237
2238         const char * const usage[] = {
2239                 N_("git am [<options>] [(<mbox>|<Maildir>)...]"),
2240                 N_("git am [<options>] (--continue | --skip | --abort)"),
2241                 NULL
2242         };
2243
2244         struct option options[] = {
2245                 OPT_BOOL('i', "interactive", &state.interactive,
2246                         N_("run interactively")),
2247                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2248                         N_("historical option -- no-op")),
2249                 OPT_BOOL('3', "3way", &state.threeway,
2250                         N_("allow fall back on 3way merging if needed")),
2251                 OPT__QUIET(&state.quiet, N_("be quiet")),
2252                 OPT_SET_INT('s', "signoff", &state.signoff,
2253                         N_("add a Signed-off-by line to the commit message"),
2254                         SIGNOFF_EXPLICIT),
2255                 OPT_BOOL('u', "utf8", &state.utf8,
2256                         N_("recode into utf8 (default)")),
2257                 OPT_SET_INT('k', "keep", &state.keep,
2258                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2259                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2260                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2261                 OPT_BOOL('m', "message-id", &state.message_id,
2262                         N_("pass -m flag to git-mailinfo")),
2263                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2264                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2265                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2266                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2267                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2268                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2269                 OPT_BOOL('c', "scissors", &state.scissors,
2270                         N_("strip everything before a scissors line")),
2271                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2272                         N_("pass it through git-apply"),
2273                         0),
2274                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2275                         N_("pass it through git-apply"),
2276                         PARSE_OPT_NOARG),
2277                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2278                         N_("pass it through git-apply"),
2279                         PARSE_OPT_NOARG),
2280                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2281                         N_("pass it through git-apply"),
2282                         0),
2283                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2284                         N_("pass it through git-apply"),
2285                         0),
2286                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2287                         N_("pass it through git-apply"),
2288                         0),
2289                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2290                         N_("pass it through git-apply"),
2291                         0),
2292                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2293                         N_("pass it through git-apply"),
2294                         0),
2295                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2296                         N_("format the patch(es) are in"),
2297                         parse_opt_patchformat),
2298                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2299                         N_("pass it through git-apply"),
2300                         PARSE_OPT_NOARG),
2301                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2302                         N_("override error message when patch failure occurs")),
2303                 OPT_CMDMODE(0, "continue", &resume,
2304                         N_("continue applying patches after resolving a conflict"),
2305                         RESUME_RESOLVED),
2306                 OPT_CMDMODE('r', "resolved", &resume,
2307                         N_("synonyms for --continue"),
2308                         RESUME_RESOLVED),
2309                 OPT_CMDMODE(0, "skip", &resume,
2310                         N_("skip the current patch"),
2311                         RESUME_SKIP),
2312                 OPT_CMDMODE(0, "abort", &resume,
2313                         N_("restore the original branch and abort the patching operation."),
2314                         RESUME_ABORT),
2315                 OPT_BOOL(0, "committer-date-is-author-date",
2316                         &state.committer_date_is_author_date,
2317                         N_("lie about committer date")),
2318                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2319                         N_("use current timestamp for author date")),
2320                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2321                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2322                   N_("GPG-sign commits"),
2323                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2324                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2325                         N_("(internal use for git-rebase)")),
2326                 OPT_END()
2327         };
2328
2329         git_config(git_am_config, NULL);
2330
2331         am_state_init(&state, git_path("rebase-apply"));
2332
2333         in_progress = am_in_progress(&state);
2334         if (in_progress)
2335                 am_load(&state);
2336
2337         argc = parse_options(argc, argv, prefix, options, usage, 0);
2338
2339         if (binary >= 0)
2340                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2341                                 "it will be removed. Please do not use it anymore."));
2342
2343         /* Ensure a valid committer ident can be constructed */
2344         git_committer_info(IDENT_STRICT);
2345
2346         if (read_index_preload(&the_index, NULL) < 0)
2347                 die(_("failed to read the index"));
2348
2349         if (in_progress) {
2350                 /*
2351                  * Catch user error to feed us patches when there is a session
2352                  * in progress:
2353                  *
2354                  * 1. mbox path(s) are provided on the command-line.
2355                  * 2. stdin is not a tty: the user is trying to feed us a patch
2356                  *    from standard input. This is somewhat unreliable -- stdin
2357                  *    could be /dev/null for example and the caller did not
2358                  *    intend to feed us a patch but wanted to continue
2359                  *    unattended.
2360                  */
2361                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2362                         die(_("previous rebase directory %s still exists but mbox given."),
2363                                 state.dir);
2364
2365                 if (resume == RESUME_FALSE)
2366                         resume = RESUME_APPLY;
2367
2368                 if (state.signoff == SIGNOFF_EXPLICIT)
2369                         am_append_signoff(&state);
2370         } else {
2371                 struct argv_array paths = ARGV_ARRAY_INIT;
2372                 int i;
2373
2374                 /*
2375                  * Handle stray state directory in the independent-run case. In
2376                  * the --rebasing case, it is up to the caller to take care of
2377                  * stray directories.
2378                  */
2379                 if (file_exists(state.dir) && !state.rebasing) {
2380                         if (resume == RESUME_ABORT) {
2381                                 am_destroy(&state);
2382                                 am_state_release(&state);
2383                                 return 0;
2384                         }
2385
2386                         die(_("Stray %s directory found.\n"
2387                                 "Use \"git am --abort\" to remove it."),
2388                                 state.dir);
2389                 }
2390
2391                 if (resume)
2392                         die(_("Resolve operation not in progress, we are not resuming."));
2393
2394                 for (i = 0; i < argc; i++) {
2395                         if (is_absolute_path(argv[i]) || !prefix)
2396                                 argv_array_push(&paths, argv[i]);
2397                         else
2398                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2399                 }
2400
2401                 am_setup(&state, patch_format, paths.argv, keep_cr);
2402
2403                 argv_array_clear(&paths);
2404         }
2405
2406         switch (resume) {
2407         case RESUME_FALSE:
2408                 am_run(&state, 0);
2409                 break;
2410         case RESUME_APPLY:
2411                 am_run(&state, 1);
2412                 break;
2413         case RESUME_RESOLVED:
2414                 am_resolve(&state);
2415                 break;
2416         case RESUME_SKIP:
2417                 am_skip(&state);
2418                 break;
2419         case RESUME_ABORT:
2420                 am_abort(&state);
2421                 break;
2422         default:
2423                 die("BUG: invalid resume value");
2424         }
2425
2426         am_state_release(&state);
2427
2428         return 0;
2429 }