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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_errno(_("could not open '%s' for reading"),
 773                                            *paths);
 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_errno(_("could not open '%s' for writing"),
 780                                            mail);
 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_errno(_("could not open '%s' for reading"), *paths);
 861
 862         while (!strbuf_getline_lf(&sb, fp)) {
 863                 if (*sb.buf == '#')
 864                         continue; /* skip comment lines */
 865
 866                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
 867         }
 868
 869         fclose(fp);
 870         strbuf_release(&sb);
 871         free(series_dir_buf);
 872
 873         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
 874
 875         argv_array_clear(&patches);
 876         return ret;
 877 }
 878
 879 /**
 880  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
 881  * message suitable for parsing with git-mailinfo.
 882  */
 883 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 884 {
 885         struct strbuf sb = STRBUF_INIT;
 886
 887         while (!strbuf_getline_lf(&sb, in)) {
 888                 const char *str;
 889
 890                 if (skip_prefix(sb.buf, "# User ", &str))
 891                         fprintf(out, "From: %s\n", str);
 892                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
 893                         unsigned long timestamp;
 894                         long tz, tz2;
 895                         char *end;
 896
 897                         errno = 0;
 898                         timestamp = strtoul(str, &end, 10);
 899                         if (errno)
 900                                 return error(_("invalid timestamp"));
 901
 902                         if (!skip_prefix(end, " ", &str))
 903                                 return error(_("invalid Date line"));
 904
 905                         errno = 0;
 906                         tz = strtol(str, &end, 10);
 907                         if (errno)
 908                                 return error(_("invalid timezone offset"));
 909
 910                         if (*end)
 911                                 return error(_("invalid Date line"));
 912
 913                         /*
 914                          * mercurial's timezone is in seconds west of UTC,
 915                          * however git's timezone is in hours + minutes east of
 916                          * UTC. Convert it.
 917                          */
 918                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
 919                         if (tz > 0)
 920                                 tz2 = -tz2;
 921
 922                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
 923                 } else if (starts_with(sb.buf, "# ")) {
 924                         continue;
 925                 } else {
 926                         fprintf(out, "\n%s\n", sb.buf);
 927                         break;
 928                 }
 929         }
 930
 931         strbuf_reset(&sb);
 932         while (strbuf_fread(&sb, 8192, in) > 0) {
 933                 fwrite(sb.buf, 1, sb.len, out);
 934                 strbuf_reset(&sb);
 935         }
 936
 937         strbuf_release(&sb);
 938         return 0;
 939 }
 940
 941 /**
 942  * Splits a list of files/directories into individual email patches. Each path
 943  * in `paths` must be a file/directory that is formatted according to
 944  * `patch_format`.
 945  *
 946  * Once split out, the individual email patches will be stored in the state
 947  * directory, with each patch's filename being its index, padded to state->prec
 948  * digits.
 949  *
 950  * state->cur will be set to the index of the first mail, and state->last will
 951  * be set to the index of the last mail.
 952  *
 953  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
 954  * to disable this behavior, -1 to use the default configured setting.
 955  *
 956  * Returns 0 on success, -1 on failure.
 957  */
 958 static int split_mail(struct am_state *state, enum patch_format patch_format,
 959                         const char **paths, int keep_cr)
 960 {
 961         if (keep_cr < 0) {
 962                 keep_cr = 0;
 963                 git_config_get_bool("am.keepcr", &keep_cr);
 964         }
 965
 966         switch (patch_format) {
 967         case PATCH_FORMAT_MBOX:
 968                 return split_mail_mbox(state, paths, keep_cr);
 969         case PATCH_FORMAT_STGIT:
 970                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 971         case PATCH_FORMAT_STGIT_SERIES:
 972                 return split_mail_stgit_series(state, paths, keep_cr);
 973         case PATCH_FORMAT_HG:
 974                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
 975         default:
 976                 die("BUG: invalid patch_format");
 977         }
 978         return -1;
 979 }
 980
 981 /**
 982  * Setup a new am session for applying patches
 983  */
 984 static void am_setup(struct am_state *state, enum patch_format patch_format,
 985                         const char **paths, int keep_cr)
 986 {
 987         unsigned char curr_head[GIT_SHA1_RAWSZ];
 988         const char *str;
 989         struct strbuf sb = STRBUF_INIT;
 990
 991         if (!patch_format)
 992                 patch_format = detect_patch_format(paths);
 993
 994         if (!patch_format) {
 995                 fprintf_ln(stderr, _("Patch format detection failed."));
 996                 exit(128);
 997         }
 998
 999         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
1000                 die_errno(_("failed to create directory '%s'"), state->dir);
1001
1002         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
1003                 am_destroy(state);
1004                 die(_("Failed to split patches."));
1005         }
1006
1007         if (state->rebasing)
1008                 state->threeway = 1;
1009
1010         write_state_bool(state, "threeway", state->threeway);
1011         write_state_bool(state, "quiet", state->quiet);
1012         write_state_bool(state, "sign", state->signoff);
1013         write_state_bool(state, "utf8", state->utf8);
1014
1015         switch (state->keep) {
1016         case KEEP_FALSE:
1017                 str = "f";
1018                 break;
1019         case KEEP_TRUE:
1020                 str = "t";
1021                 break;
1022         case KEEP_NON_PATCH:
1023                 str = "b";
1024                 break;
1025         default:
1026                 die("BUG: invalid value for state->keep");
1027         }
1028
1029         write_state_text(state, "keep", str);
1030         write_state_bool(state, "messageid", state->message_id);
1031
1032         switch (state->scissors) {
1033         case SCISSORS_UNSET:
1034                 str = "";
1035                 break;
1036         case SCISSORS_FALSE:
1037                 str = "f";
1038                 break;
1039         case SCISSORS_TRUE:
1040                 str = "t";
1041                 break;
1042         default:
1043                 die("BUG: invalid value for state->scissors");
1044         }
1045         write_state_text(state, "scissors", str);
1046
1047         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1048         write_state_text(state, "apply-opt", sb.buf);
1049
1050         if (state->rebasing)
1051                 write_state_text(state, "rebasing", "");
1052         else
1053                 write_state_text(state, "applying", "");
1054
1055         if (!get_sha1("HEAD", curr_head)) {
1056                 write_state_text(state, "abort-safety", sha1_to_hex(curr_head));
1057                 if (!state->rebasing)
1058                         update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
1059                                         UPDATE_REFS_DIE_ON_ERR);
1060         } else {
1061                 write_state_text(state, "abort-safety", "");
1062                 if (!state->rebasing)
1063                         delete_ref("ORIG_HEAD", NULL, 0);
1064         }
1065
1066         /*
1067          * NOTE: Since the "next" and "last" files determine if an am_state
1068          * session is in progress, they should be written last.
1069          */
1070
1071         write_state_count(state, "next", state->cur);
1072         write_state_count(state, "last", state->last);
1073
1074         strbuf_release(&sb);
1075 }
1076
1077 /**
1078  * Increments the patch pointer, and cleans am_state for the application of the
1079  * next patch.
1080  */
1081 static void am_next(struct am_state *state)
1082 {
1083         unsigned char head[GIT_SHA1_RAWSZ];
1084
1085         free(state->author_name);
1086         state->author_name = NULL;
1087
1088         free(state->author_email);
1089         state->author_email = NULL;
1090
1091         free(state->author_date);
1092         state->author_date = NULL;
1093
1094         free(state->msg);
1095         state->msg = NULL;
1096         state->msg_len = 0;
1097
1098         unlink(am_path(state, "author-script"));
1099         unlink(am_path(state, "final-commit"));
1100
1101         hashclr(state->orig_commit);
1102         unlink(am_path(state, "original-commit"));
1103
1104         if (!get_sha1("HEAD", head))
1105                 write_state_text(state, "abort-safety", sha1_to_hex(head));
1106         else
1107                 write_state_text(state, "abort-safety", "");
1108
1109         state->cur++;
1110         write_state_count(state, "next", state->cur);
1111 }
1112
1113 /**
1114  * Returns the filename of the current patch email.
1115  */
1116 static const char *msgnum(const struct am_state *state)
1117 {
1118         static struct strbuf sb = STRBUF_INIT;
1119
1120         strbuf_reset(&sb);
1121         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1122
1123         return sb.buf;
1124 }
1125
1126 /**
1127  * Refresh and write index.
1128  */
1129 static void refresh_and_write_cache(void)
1130 {
1131         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1132
1133         hold_locked_index(lock_file, 1);
1134         refresh_cache(REFRESH_QUIET);
1135         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1136                 die(_("unable to write index file"));
1137 }
1138
1139 /**
1140  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1141  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1142  * strbuf is provided, the space-separated list of files that differ will be
1143  * appended to it.
1144  */
1145 static int index_has_changes(struct strbuf *sb)
1146 {
1147         unsigned char head[GIT_SHA1_RAWSZ];
1148         int i;
1149
1150         if (!get_sha1_tree("HEAD", head)) {
1151                 struct diff_options opt;
1152
1153                 diff_setup(&opt);
1154                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1155                 if (!sb)
1156                         DIFF_OPT_SET(&opt, QUICK);
1157                 do_diff_cache(head, &opt);
1158                 diffcore_std(&opt);
1159                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1160                         if (i)
1161                                 strbuf_addch(sb, ' ');
1162                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1163                 }
1164                 diff_flush(&opt);
1165                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1166         } else {
1167                 for (i = 0; sb && i < active_nr; i++) {
1168                         if (i)
1169                                 strbuf_addch(sb, ' ');
1170                         strbuf_addstr(sb, active_cache[i]->name);
1171                 }
1172                 return !!active_nr;
1173         }
1174 }
1175
1176 /**
1177  * Dies with a user-friendly message on how to proceed after resolving the
1178  * problem. This message can be overridden with state->resolvemsg.
1179  */
1180 static void NORETURN die_user_resolve(const struct am_state *state)
1181 {
1182         if (state->resolvemsg) {
1183                 printf_ln("%s", state->resolvemsg);
1184         } else {
1185                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1186
1187                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1188                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1189                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1190         }
1191
1192         exit(128);
1193 }
1194
1195 static void am_signoff(struct strbuf *sb)
1196 {
1197         char *cp;
1198         struct strbuf mine = STRBUF_INIT;
1199
1200         /* Does it end with our own sign-off? */
1201         strbuf_addf(&mine, "\n%s%s\n",
1202                     sign_off_header,
1203                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1204                              getenv("GIT_COMMITTER_EMAIL")));
1205         if (mine.len < sb->len &&
1206             !strcmp(mine.buf, sb->buf + sb->len - mine.len))
1207                 goto exit; /* no need to duplicate */
1208
1209         /* Does it have any Signed-off-by: in the text */
1210         for (cp = sb->buf;
1211              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1212              cp = strchr(cp, '\n')) {
1213                 if (sb->buf == cp || cp[-1] == '\n')
1214                         break;
1215         }
1216
1217         strbuf_addstr(sb, mine.buf + !!cp);
1218 exit:
1219         strbuf_release(&mine);
1220 }
1221
1222 /**
1223  * Appends signoff to the "msg" field of the am_state.
1224  */
1225 static void am_append_signoff(struct am_state *state)
1226 {
1227         struct strbuf sb = STRBUF_INIT;
1228
1229         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1230         am_signoff(&sb);
1231         state->msg = strbuf_detach(&sb, &state->msg_len);
1232 }
1233
1234 /**
1235  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1236  * state->msg will be set to the patch message. state->author_name,
1237  * state->author_email and state->author_date will be set to the patch author's
1238  * name, email and date respectively. The patch body will be written to the
1239  * state directory's "patch" file.
1240  *
1241  * Returns 1 if the patch should be skipped, 0 otherwise.
1242  */
1243 static int parse_mail(struct am_state *state, const char *mail)
1244 {
1245         FILE *fp;
1246         struct strbuf sb = STRBUF_INIT;
1247         struct strbuf msg = STRBUF_INIT;
1248         struct strbuf author_name = STRBUF_INIT;
1249         struct strbuf author_date = STRBUF_INIT;
1250         struct strbuf author_email = STRBUF_INIT;
1251         int ret = 0;
1252         struct mailinfo mi;
1253
1254         setup_mailinfo(&mi);
1255
1256         if (state->utf8)
1257                 mi.metainfo_charset = get_commit_output_encoding();
1258         else
1259                 mi.metainfo_charset = NULL;
1260
1261         switch (state->keep) {
1262         case KEEP_FALSE:
1263                 break;
1264         case KEEP_TRUE:
1265                 mi.keep_subject = 1;
1266                 break;
1267         case KEEP_NON_PATCH:
1268                 mi.keep_non_patch_brackets_in_subject = 1;
1269                 break;
1270         default:
1271                 die("BUG: invalid value for state->keep");
1272         }
1273
1274         if (state->message_id)
1275                 mi.add_message_id = 1;
1276
1277         switch (state->scissors) {
1278         case SCISSORS_UNSET:
1279                 break;
1280         case SCISSORS_FALSE:
1281                 mi.use_scissors = 0;
1282                 break;
1283         case SCISSORS_TRUE:
1284                 mi.use_scissors = 1;
1285                 break;
1286         default:
1287                 die("BUG: invalid value for state->scissors");
1288         }
1289
1290         mi.input = fopen(mail, "r");
1291         if (!mi.input)
1292                 die("could not open input");
1293         mi.output = fopen(am_path(state, "info"), "w");
1294         if (!mi.output)
1295                 die("could not open output 'info'");
1296         if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
1297                 die("could not parse patch");
1298
1299         fclose(mi.input);
1300         fclose(mi.output);
1301
1302         /* Extract message and author information */
1303         fp = xfopen(am_path(state, "info"), "r");
1304         while (!strbuf_getline_lf(&sb, fp)) {
1305                 const char *x;
1306
1307                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1308                         if (msg.len)
1309                                 strbuf_addch(&msg, '\n');
1310                         strbuf_addstr(&msg, x);
1311                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1312                         strbuf_addstr(&author_name, x);
1313                 else if (skip_prefix(sb.buf, "Email: ", &x))
1314                         strbuf_addstr(&author_email, x);
1315                 else if (skip_prefix(sb.buf, "Date: ", &x))
1316                         strbuf_addstr(&author_date, x);
1317         }
1318         fclose(fp);
1319
1320         /* Skip pine's internal folder data */
1321         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1322                 ret = 1;
1323                 goto finish;
1324         }
1325
1326         if (is_empty_file(am_path(state, "patch"))) {
1327                 printf_ln(_("Patch is empty. Was it split wrong?"));
1328                 die_user_resolve(state);
1329         }
1330
1331         strbuf_addstr(&msg, "\n\n");
1332         strbuf_addbuf(&msg, &mi.log_message);
1333         strbuf_stripspace(&msg, 0);
1334
1335         if (state->signoff)
1336                 am_signoff(&msg);
1337
1338         assert(!state->author_name);
1339         state->author_name = strbuf_detach(&author_name, NULL);
1340
1341         assert(!state->author_email);
1342         state->author_email = strbuf_detach(&author_email, NULL);
1343
1344         assert(!state->author_date);
1345         state->author_date = strbuf_detach(&author_date, NULL);
1346
1347         assert(!state->msg);
1348         state->msg = strbuf_detach(&msg, &state->msg_len);
1349
1350 finish:
1351         strbuf_release(&msg);
1352         strbuf_release(&author_date);
1353         strbuf_release(&author_email);
1354         strbuf_release(&author_name);
1355         strbuf_release(&sb);
1356         clear_mailinfo(&mi);
1357         return ret;
1358 }
1359
1360 /**
1361  * Sets commit_id to the commit hash where the mail was generated from.
1362  * Returns 0 on success, -1 on failure.
1363  */
1364 static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
1365 {
1366         struct strbuf sb = STRBUF_INIT;
1367         FILE *fp = xfopen(mail, "r");
1368         const char *x;
1369
1370         if (strbuf_getline_lf(&sb, fp))
1371                 return -1;
1372
1373         if (!skip_prefix(sb.buf, "From ", &x))
1374                 return -1;
1375
1376         if (get_sha1_hex(x, commit_id) < 0)
1377                 return -1;
1378
1379         strbuf_release(&sb);
1380         fclose(fp);
1381         return 0;
1382 }
1383
1384 /**
1385  * Sets state->msg, state->author_name, state->author_email, state->author_date
1386  * to the commit's respective info.
1387  */
1388 static void get_commit_info(struct am_state *state, struct commit *commit)
1389 {
1390         const char *buffer, *ident_line, *author_date, *msg;
1391         size_t ident_len;
1392         struct ident_split ident_split;
1393         struct strbuf sb = STRBUF_INIT;
1394
1395         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1396
1397         ident_line = find_commit_header(buffer, "author", &ident_len);
1398
1399         if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
1400                 strbuf_add(&sb, ident_line, ident_len);
1401                 die(_("invalid ident line: %s"), sb.buf);
1402         }
1403
1404         assert(!state->author_name);
1405         if (ident_split.name_begin) {
1406                 strbuf_add(&sb, ident_split.name_begin,
1407                         ident_split.name_end - ident_split.name_begin);
1408                 state->author_name = strbuf_detach(&sb, NULL);
1409         } else
1410                 state->author_name = xstrdup("");
1411
1412         assert(!state->author_email);
1413         if (ident_split.mail_begin) {
1414                 strbuf_add(&sb, ident_split.mail_begin,
1415                         ident_split.mail_end - ident_split.mail_begin);
1416                 state->author_email = strbuf_detach(&sb, NULL);
1417         } else
1418                 state->author_email = xstrdup("");
1419
1420         author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
1421         strbuf_addstr(&sb, author_date);
1422         assert(!state->author_date);
1423         state->author_date = strbuf_detach(&sb, NULL);
1424
1425         assert(!state->msg);
1426         msg = strstr(buffer, "\n\n");
1427         if (!msg)
1428                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1429         state->msg = xstrdup(msg + 2);
1430         state->msg_len = strlen(state->msg);
1431 }
1432
1433 /**
1434  * Writes `commit` as a patch to the state directory's "patch" file.
1435  */
1436 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1437 {
1438         struct rev_info rev_info;
1439         FILE *fp;
1440
1441         fp = xfopen(am_path(state, "patch"), "w");
1442         init_revisions(&rev_info, NULL);
1443         rev_info.diff = 1;
1444         rev_info.abbrev = 0;
1445         rev_info.disable_stdin = 1;
1446         rev_info.show_root_diff = 1;
1447         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1448         rev_info.no_commit_id = 1;
1449         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1450         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1451         rev_info.diffopt.use_color = 0;
1452         rev_info.diffopt.file = fp;
1453         rev_info.diffopt.close_file = 1;
1454         add_pending_object(&rev_info, &commit->object, "");
1455         diff_setup_done(&rev_info.diffopt);
1456         log_tree_commit(&rev_info, commit);
1457 }
1458
1459 /**
1460  * Writes the diff of the index against HEAD as a patch to the state
1461  * directory's "patch" file.
1462  */
1463 static void write_index_patch(const struct am_state *state)
1464 {
1465         struct tree *tree;
1466         unsigned char head[GIT_SHA1_RAWSZ];
1467         struct rev_info rev_info;
1468         FILE *fp;
1469
1470         if (!get_sha1_tree("HEAD", head))
1471                 tree = lookup_tree(head);
1472         else
1473                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1474
1475         fp = xfopen(am_path(state, "patch"), "w");
1476         init_revisions(&rev_info, NULL);
1477         rev_info.diff = 1;
1478         rev_info.disable_stdin = 1;
1479         rev_info.no_commit_id = 1;
1480         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1481         rev_info.diffopt.use_color = 0;
1482         rev_info.diffopt.file = fp;
1483         rev_info.diffopt.close_file = 1;
1484         add_pending_object(&rev_info, &tree->object, "");
1485         diff_setup_done(&rev_info.diffopt);
1486         run_diff_index(&rev_info, 1);
1487 }
1488
1489 /**
1490  * Like parse_mail(), but parses the mail by looking up its commit ID
1491  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1492  * of patches.
1493  *
1494  * state->orig_commit will be set to the original commit ID.
1495  *
1496  * Will always return 0 as the patch should never be skipped.
1497  */
1498 static int parse_mail_rebase(struct am_state *state, const char *mail)
1499 {
1500         struct commit *commit;
1501         unsigned char commit_sha1[GIT_SHA1_RAWSZ];
1502
1503         if (get_mail_commit_sha1(commit_sha1, mail) < 0)
1504                 die(_("could not parse %s"), mail);
1505
1506         commit = lookup_commit_or_die(commit_sha1, mail);
1507
1508         get_commit_info(state, commit);
1509
1510         write_commit_patch(state, commit);
1511
1512         hashcpy(state->orig_commit, commit_sha1);
1513         write_state_text(state, "original-commit", sha1_to_hex(commit_sha1));
1514
1515         return 0;
1516 }
1517
1518 /**
1519  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1520  * `index_file` is not NULL, the patch will be applied to that index.
1521  */
1522 static int run_apply(const struct am_state *state, const char *index_file)
1523 {
1524         struct child_process cp = CHILD_PROCESS_INIT;
1525
1526         cp.git_cmd = 1;
1527
1528         if (index_file)
1529                 argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
1530
1531         /*
1532          * If we are allowed to fall back on 3-way merge, don't give false
1533          * errors during the initial attempt.
1534          */
1535         if (state->threeway && !index_file) {
1536                 cp.no_stdout = 1;
1537                 cp.no_stderr = 1;
1538         }
1539
1540         argv_array_push(&cp.args, "apply");
1541
1542         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1543
1544         if (index_file)
1545                 argv_array_push(&cp.args, "--cached");
1546         else
1547                 argv_array_push(&cp.args, "--index");
1548
1549         argv_array_push(&cp.args, am_path(state, "patch"));
1550
1551         if (run_command(&cp))
1552                 return -1;
1553
1554         /* Reload index as git-apply will have modified it. */
1555         discard_cache();
1556         read_cache_from(index_file ? index_file : get_index_file());
1557
1558         return 0;
1559 }
1560
1561 /**
1562  * Builds an index that contains just the blobs needed for a 3way merge.
1563  */
1564 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1565 {
1566         struct child_process cp = CHILD_PROCESS_INIT;
1567
1568         cp.git_cmd = 1;
1569         argv_array_push(&cp.args, "apply");
1570         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1571         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1572         argv_array_push(&cp.args, am_path(state, "patch"));
1573
1574         if (run_command(&cp))
1575                 return -1;
1576
1577         return 0;
1578 }
1579
1580 /**
1581  * Do the three-way merge using fake ancestor, his tree constructed
1582  * from the fake ancestor and the postimage of the patch, and our
1583  * state.
1584  */
1585 static int run_fallback_merge_recursive(const struct am_state *state,
1586                                         unsigned char *orig_tree,
1587                                         unsigned char *our_tree,
1588                                         unsigned char *his_tree)
1589 {
1590         struct child_process cp = CHILD_PROCESS_INIT;
1591         int status;
1592
1593         cp.git_cmd = 1;
1594
1595         argv_array_pushf(&cp.env_array, "GITHEAD_%s=%.*s",
1596                          sha1_to_hex(his_tree), linelen(state->msg), state->msg);
1597         if (state->quiet)
1598                 argv_array_push(&cp.env_array, "GIT_MERGE_VERBOSITY=0");
1599
1600         argv_array_push(&cp.args, "merge-recursive");
1601         argv_array_push(&cp.args, sha1_to_hex(orig_tree));
1602         argv_array_push(&cp.args, "--");
1603         argv_array_push(&cp.args, sha1_to_hex(our_tree));
1604         argv_array_push(&cp.args, sha1_to_hex(his_tree));
1605
1606         status = run_command(&cp) ? (-1) : 0;
1607         discard_cache();
1608         read_cache();
1609         return status;
1610 }
1611
1612 /**
1613  * Attempt a threeway merge, using index_path as the temporary index.
1614  */
1615 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1616 {
1617         unsigned char orig_tree[GIT_SHA1_RAWSZ], his_tree[GIT_SHA1_RAWSZ],
1618                       our_tree[GIT_SHA1_RAWSZ];
1619
1620         if (get_sha1("HEAD", our_tree) < 0)
1621                 hashcpy(our_tree, EMPTY_TREE_SHA1_BIN);
1622
1623         if (build_fake_ancestor(state, index_path))
1624                 return error("could not build fake ancestor");
1625
1626         discard_cache();
1627         read_cache_from(index_path);
1628
1629         if (write_index_as_tree(orig_tree, &the_index, index_path, 0, NULL))
1630                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1631
1632         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1633
1634         if (!state->quiet) {
1635                 /*
1636                  * List paths that needed 3-way fallback, so that the user can
1637                  * review them with extra care to spot mismerges.
1638                  */
1639                 struct rev_info rev_info;
1640                 const char *diff_filter_str = "--diff-filter=AM";
1641
1642                 init_revisions(&rev_info, NULL);
1643                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1644                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1645                 add_pending_sha1(&rev_info, "HEAD", our_tree, 0);
1646                 diff_setup_done(&rev_info.diffopt);
1647                 run_diff_index(&rev_info, 1);
1648         }
1649
1650         if (run_apply(state, index_path))
1651                 return error(_("Did you hand edit your patch?\n"
1652                                 "It does not apply to blobs recorded in its index."));
1653
1654         if (write_index_as_tree(his_tree, &the_index, index_path, 0, NULL))
1655                 return error("could not write tree");
1656
1657         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1658
1659         discard_cache();
1660         read_cache();
1661
1662         /*
1663          * This is not so wrong. Depending on which base we picked, orig_tree
1664          * may be wildly different from ours, but his_tree has the same set of
1665          * wildly different changes in parts the patch did not touch, so
1666          * recursive ends up canceling them, saying that we reverted all those
1667          * changes.
1668          */
1669
1670         if (run_fallback_merge_recursive(state, orig_tree, our_tree, his_tree)) {
1671                 rerere(state->allow_rerere_autoupdate);
1672                 return error(_("Failed to merge in the changes."));
1673         }
1674
1675         return 0;
1676 }
1677
1678 /**
1679  * Commits the current index with state->msg as the commit message and
1680  * state->author_name, state->author_email and state->author_date as the author
1681  * information.
1682  */
1683 static void do_commit(const struct am_state *state)
1684 {
1685         unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
1686                       commit[GIT_SHA1_RAWSZ];
1687         unsigned char *ptr;
1688         struct commit_list *parents = NULL;
1689         const char *reflog_msg, *author;
1690         struct strbuf sb = STRBUF_INIT;
1691
1692         if (run_hook_le(NULL, "pre-applypatch", NULL))
1693                 exit(1);
1694
1695         if (write_cache_as_tree(tree, 0, NULL))
1696                 die(_("git write-tree failed to write a tree"));
1697
1698         if (!get_sha1_commit("HEAD", parent)) {
1699                 ptr = parent;
1700                 commit_list_insert(lookup_commit(parent), &parents);
1701         } else {
1702                 ptr = NULL;
1703                 say(state, stderr, _("applying to an empty history"));
1704         }
1705
1706         author = fmt_ident(state->author_name, state->author_email,
1707                         state->ignore_date ? NULL : state->author_date,
1708                         IDENT_STRICT);
1709
1710         if (state->committer_date_is_author_date)
1711                 setenv("GIT_COMMITTER_DATE",
1712                         state->ignore_date ? "" : state->author_date, 1);
1713
1714         if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
1715                                 author, state->sign_commit))
1716                 die(_("failed to write commit object"));
1717
1718         reflog_msg = getenv("GIT_REFLOG_ACTION");
1719         if (!reflog_msg)
1720                 reflog_msg = "am";
1721
1722         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1723                         state->msg);
1724
1725         update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
1726
1727         if (state->rebasing) {
1728                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1729
1730                 assert(!is_null_sha1(state->orig_commit));
1731                 fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
1732                 fprintf(fp, "%s\n", sha1_to_hex(commit));
1733                 fclose(fp);
1734         }
1735
1736         run_hook_le(NULL, "post-applypatch", NULL);
1737
1738         strbuf_release(&sb);
1739 }
1740
1741 /**
1742  * Validates the am_state for resuming -- the "msg" and authorship fields must
1743  * be filled up.
1744  */
1745 static void validate_resume_state(const struct am_state *state)
1746 {
1747         if (!state->msg)
1748                 die(_("cannot resume: %s does not exist."),
1749                         am_path(state, "final-commit"));
1750
1751         if (!state->author_name || !state->author_email || !state->author_date)
1752                 die(_("cannot resume: %s does not exist."),
1753                         am_path(state, "author-script"));
1754 }
1755
1756 /**
1757  * Interactively prompt the user on whether the current patch should be
1758  * applied.
1759  *
1760  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1761  * skip it.
1762  */
1763 static int do_interactive(struct am_state *state)
1764 {
1765         assert(state->msg);
1766
1767         if (!isatty(0))
1768                 die(_("cannot be interactive without stdin connected to a terminal."));
1769
1770         for (;;) {
1771                 const char *reply;
1772
1773                 puts(_("Commit Body is:"));
1774                 puts("--------------------------");
1775                 printf("%s", state->msg);
1776                 puts("--------------------------");
1777
1778                 /*
1779                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1780                  * in your translation. The program will only accept English
1781                  * input at this point.
1782                  */
1783                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1784
1785                 if (!reply) {
1786                         continue;
1787                 } else if (*reply == 'y' || *reply == 'Y') {
1788                         return 0;
1789                 } else if (*reply == 'a' || *reply == 'A') {
1790                         state->interactive = 0;
1791                         return 0;
1792                 } else if (*reply == 'n' || *reply == 'N') {
1793                         return 1;
1794                 } else if (*reply == 'e' || *reply == 'E') {
1795                         struct strbuf msg = STRBUF_INIT;
1796
1797                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1798                                 free(state->msg);
1799                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1800                         }
1801                         strbuf_release(&msg);
1802                 } else if (*reply == 'v' || *reply == 'V') {
1803                         const char *pager = git_pager(1);
1804                         struct child_process cp = CHILD_PROCESS_INIT;
1805
1806                         if (!pager)
1807                                 pager = "cat";
1808                         prepare_pager_args(&cp, pager);
1809                         argv_array_push(&cp.args, am_path(state, "patch"));
1810                         run_command(&cp);
1811                 }
1812         }
1813 }
1814
1815 /**
1816  * Applies all queued mail.
1817  *
1818  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1819  * well as the state directory's "patch" file is used as-is for applying the
1820  * patch and committing it.
1821  */
1822 static void am_run(struct am_state *state, int resume)
1823 {
1824         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1825         struct strbuf sb = STRBUF_INIT;
1826
1827         unlink(am_path(state, "dirtyindex"));
1828
1829         refresh_and_write_cache();
1830
1831         if (index_has_changes(&sb)) {
1832                 write_state_bool(state, "dirtyindex", 1);
1833                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1834         }
1835
1836         strbuf_release(&sb);
1837
1838         while (state->cur <= state->last) {
1839                 const char *mail = am_path(state, msgnum(state));
1840                 int apply_status;
1841
1842                 if (!file_exists(mail))
1843                         goto next;
1844
1845                 if (resume) {
1846                         validate_resume_state(state);
1847                 } else {
1848                         int skip;
1849
1850                         if (state->rebasing)
1851                                 skip = parse_mail_rebase(state, mail);
1852                         else
1853                                 skip = parse_mail(state, mail);
1854
1855                         if (skip)
1856                                 goto next; /* mail should be skipped */
1857
1858                         write_author_script(state);
1859                         write_commit_msg(state);
1860                 }
1861
1862                 if (state->interactive && do_interactive(state))
1863                         goto next;
1864
1865                 if (run_applypatch_msg_hook(state))
1866                         exit(1);
1867
1868                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1869
1870                 apply_status = run_apply(state, NULL);
1871
1872                 if (apply_status && state->threeway) {
1873                         struct strbuf sb = STRBUF_INIT;
1874
1875                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1876                         apply_status = fall_back_threeway(state, sb.buf);
1877                         strbuf_release(&sb);
1878
1879                         /*
1880                          * Applying the patch to an earlier tree and merging
1881                          * the result may have produced the same tree as ours.
1882                          */
1883                         if (!apply_status && !index_has_changes(NULL)) {
1884                                 say(state, stdout, _("No changes -- Patch already applied."));
1885                                 goto next;
1886                         }
1887                 }
1888
1889                 if (apply_status) {
1890                         int advice_amworkdir = 1;
1891
1892                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1893                                 linelen(state->msg), state->msg);
1894
1895                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1896
1897                         if (advice_amworkdir)
1898                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1899                                                 am_path(state, "patch"));
1900
1901                         die_user_resolve(state);
1902                 }
1903
1904                 do_commit(state);
1905
1906 next:
1907                 am_next(state);
1908
1909                 if (resume)
1910                         am_load(state);
1911                 resume = 0;
1912         }
1913
1914         if (!is_empty_file(am_path(state, "rewritten"))) {
1915                 assert(state->rebasing);
1916                 copy_notes_for_rebase(state);
1917                 run_post_rewrite_hook(state);
1918         }
1919
1920         /*
1921          * In rebasing mode, it's up to the caller to take care of
1922          * housekeeping.
1923          */
1924         if (!state->rebasing) {
1925                 am_destroy(state);
1926                 close_all_packs();
1927                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1928         }
1929 }
1930
1931 /**
1932  * Resume the current am session after patch application failure. The user did
1933  * all the hard work, and we do not have to do any patch application. Just
1934  * trust and commit what the user has in the index and working tree.
1935  */
1936 static void am_resolve(struct am_state *state)
1937 {
1938         validate_resume_state(state);
1939
1940         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1941
1942         if (!index_has_changes(NULL)) {
1943                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1944                         "If there is nothing left to stage, chances are that something else\n"
1945                         "already introduced the same changes; you might want to skip this patch."));
1946                 die_user_resolve(state);
1947         }
1948
1949         if (unmerged_cache()) {
1950                 printf_ln(_("You still have unmerged paths in your index.\n"
1951                         "Did you forget to use 'git add'?"));
1952                 die_user_resolve(state);
1953         }
1954
1955         if (state->interactive) {
1956                 write_index_patch(state);
1957                 if (do_interactive(state))
1958                         goto next;
1959         }
1960
1961         rerere(0);
1962
1963         do_commit(state);
1964
1965 next:
1966         am_next(state);
1967         am_load(state);
1968         am_run(state, 0);
1969 }
1970
1971 /**
1972  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1973  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1974  * failure.
1975  */
1976 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1977 {
1978         struct lock_file *lock_file;
1979         struct unpack_trees_options opts;
1980         struct tree_desc t[2];
1981
1982         if (parse_tree(head) || parse_tree(remote))
1983                 return -1;
1984
1985         lock_file = xcalloc(1, sizeof(struct lock_file));
1986         hold_locked_index(lock_file, 1);
1987
1988         refresh_cache(REFRESH_QUIET);
1989
1990         memset(&opts, 0, sizeof(opts));
1991         opts.head_idx = 1;
1992         opts.src_index = &the_index;
1993         opts.dst_index = &the_index;
1994         opts.update = 1;
1995         opts.merge = 1;
1996         opts.reset = reset;
1997         opts.fn = twoway_merge;
1998         init_tree_desc(&t[0], head->buffer, head->size);
1999         init_tree_desc(&t[1], remote->buffer, remote->size);
2000
2001         if (unpack_trees(2, t, &opts)) {
2002                 rollback_lock_file(lock_file);
2003                 return -1;
2004         }
2005
2006         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2007                 die(_("unable to write new index file"));
2008
2009         return 0;
2010 }
2011
2012 /**
2013  * Merges a tree into the index. The index's stat info will take precedence
2014  * over the merged tree's. Returns 0 on success, -1 on failure.
2015  */
2016 static int merge_tree(struct tree *tree)
2017 {
2018         struct lock_file *lock_file;
2019         struct unpack_trees_options opts;
2020         struct tree_desc t[1];
2021
2022         if (parse_tree(tree))
2023                 return -1;
2024
2025         lock_file = xcalloc(1, sizeof(struct lock_file));
2026         hold_locked_index(lock_file, 1);
2027
2028         memset(&opts, 0, sizeof(opts));
2029         opts.head_idx = 1;
2030         opts.src_index = &the_index;
2031         opts.dst_index = &the_index;
2032         opts.merge = 1;
2033         opts.fn = oneway_merge;
2034         init_tree_desc(&t[0], tree->buffer, tree->size);
2035
2036         if (unpack_trees(1, t, &opts)) {
2037                 rollback_lock_file(lock_file);
2038                 return -1;
2039         }
2040
2041         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2042                 die(_("unable to write new index file"));
2043
2044         return 0;
2045 }
2046
2047 /**
2048  * Clean the index without touching entries that are not modified between
2049  * `head` and `remote`.
2050  */
2051 static int clean_index(const unsigned char *head, const unsigned char *remote)
2052 {
2053         struct tree *head_tree, *remote_tree, *index_tree;
2054         unsigned char index[GIT_SHA1_RAWSZ];
2055
2056         head_tree = parse_tree_indirect(head);
2057         if (!head_tree)
2058                 return error(_("Could not parse object '%s'."), sha1_to_hex(head));
2059
2060         remote_tree = parse_tree_indirect(remote);
2061         if (!remote_tree)
2062                 return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
2063
2064         read_cache_unmerged();
2065
2066         if (fast_forward_to(head_tree, head_tree, 1))
2067                 return -1;
2068
2069         if (write_cache_as_tree(index, 0, NULL))
2070                 return -1;
2071
2072         index_tree = parse_tree_indirect(index);
2073         if (!index_tree)
2074                 return error(_("Could not parse object '%s'."), sha1_to_hex(index));
2075
2076         if (fast_forward_to(index_tree, remote_tree, 0))
2077                 return -1;
2078
2079         if (merge_tree(remote_tree))
2080                 return -1;
2081
2082         remove_branch_state();
2083
2084         return 0;
2085 }
2086
2087 /**
2088  * Resets rerere's merge resolution metadata.
2089  */
2090 static void am_rerere_clear(void)
2091 {
2092         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2093         rerere_clear(&merge_rr);
2094         string_list_clear(&merge_rr, 1);
2095 }
2096
2097 /**
2098  * Resume the current am session by skipping the current patch.
2099  */
2100 static void am_skip(struct am_state *state)
2101 {
2102         unsigned char head[GIT_SHA1_RAWSZ];
2103
2104         am_rerere_clear();
2105
2106         if (get_sha1("HEAD", head))
2107                 hashcpy(head, EMPTY_TREE_SHA1_BIN);
2108
2109         if (clean_index(head, head))
2110                 die(_("failed to clean index"));
2111
2112         am_next(state);
2113         am_load(state);
2114         am_run(state, 0);
2115 }
2116
2117 /**
2118  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2119  *
2120  * It is not safe to reset HEAD when:
2121  * 1. git-am previously failed because the index was dirty.
2122  * 2. HEAD has moved since git-am previously failed.
2123  */
2124 static int safe_to_abort(const struct am_state *state)
2125 {
2126         struct strbuf sb = STRBUF_INIT;
2127         unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
2128
2129         if (file_exists(am_path(state, "dirtyindex")))
2130                 return 0;
2131
2132         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2133                 if (get_sha1_hex(sb.buf, abort_safety))
2134                         die(_("could not parse %s"), am_path(state, "abort_safety"));
2135         } else
2136                 hashclr(abort_safety);
2137
2138         if (get_sha1("HEAD", head))
2139                 hashclr(head);
2140
2141         if (!hashcmp(head, abort_safety))
2142                 return 1;
2143
2144         error(_("You seem to have moved HEAD since the last 'am' failure.\n"
2145                 "Not rewinding to ORIG_HEAD"));
2146
2147         return 0;
2148 }
2149
2150 /**
2151  * Aborts the current am session if it is safe to do so.
2152  */
2153 static void am_abort(struct am_state *state)
2154 {
2155         unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
2156         int has_curr_head, has_orig_head;
2157         char *curr_branch;
2158
2159         if (!safe_to_abort(state)) {
2160                 am_destroy(state);
2161                 return;
2162         }
2163
2164         am_rerere_clear();
2165
2166         curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
2167         has_curr_head = !is_null_sha1(curr_head);
2168         if (!has_curr_head)
2169                 hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
2170
2171         has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
2172         if (!has_orig_head)
2173                 hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
2174
2175         clean_index(curr_head, orig_head);
2176
2177         if (has_orig_head)
2178                 update_ref("am --abort", "HEAD", orig_head,
2179                                 has_curr_head ? curr_head : NULL, 0,
2180                                 UPDATE_REFS_DIE_ON_ERR);
2181         else if (curr_branch)
2182                 delete_ref(curr_branch, NULL, REF_NODEREF);
2183
2184         free(curr_branch);
2185         am_destroy(state);
2186 }
2187
2188 /**
2189  * parse_options() callback that validates and sets opt->value to the
2190  * PATCH_FORMAT_* enum value corresponding to `arg`.
2191  */
2192 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2193 {
2194         int *opt_value = opt->value;
2195
2196         if (!strcmp(arg, "mbox"))
2197                 *opt_value = PATCH_FORMAT_MBOX;
2198         else if (!strcmp(arg, "stgit"))
2199                 *opt_value = PATCH_FORMAT_STGIT;
2200         else if (!strcmp(arg, "stgit-series"))
2201                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2202         else if (!strcmp(arg, "hg"))
2203                 *opt_value = PATCH_FORMAT_HG;
2204         else
2205                 return error(_("Invalid value for --patch-format: %s"), arg);
2206         return 0;
2207 }
2208
2209 enum resume_mode {
2210         RESUME_FALSE = 0,
2211         RESUME_APPLY,
2212         RESUME_RESOLVED,
2213         RESUME_SKIP,
2214         RESUME_ABORT
2215 };
2216
2217 static int git_am_config(const char *k, const char *v, void *cb)
2218 {
2219         int status;
2220
2221         status = git_gpg_config(k, v, NULL);
2222         if (status)
2223                 return status;
2224
2225         return git_default_config(k, v, NULL);
2226 }
2227
2228 int cmd_am(int argc, const char **argv, const char *prefix)
2229 {
2230         struct am_state state;
2231         int binary = -1;
2232         int keep_cr = -1;
2233         int patch_format = PATCH_FORMAT_UNKNOWN;
2234         enum resume_mode resume = RESUME_FALSE;
2235         int in_progress;
2236
2237         const char * const usage[] = {
2238                 N_("git am [<options>] [(<mbox>|<Maildir>)...]"),
2239                 N_("git am [<options>] (--continue | --skip | --abort)"),
2240                 NULL
2241         };
2242
2243         struct option options[] = {
2244                 OPT_BOOL('i', "interactive", &state.interactive,
2245                         N_("run interactively")),
2246                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2247                         N_("historical option -- no-op")),
2248                 OPT_BOOL('3', "3way", &state.threeway,
2249                         N_("allow fall back on 3way merging if needed")),
2250                 OPT__QUIET(&state.quiet, N_("be quiet")),
2251                 OPT_SET_INT('s', "signoff", &state.signoff,
2252                         N_("add a Signed-off-by line to the commit message"),
2253                         SIGNOFF_EXPLICIT),
2254                 OPT_BOOL('u', "utf8", &state.utf8,
2255                         N_("recode into utf8 (default)")),
2256                 OPT_SET_INT('k', "keep", &state.keep,
2257                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2258                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2259                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2260                 OPT_BOOL('m', "message-id", &state.message_id,
2261                         N_("pass -m flag to git-mailinfo")),
2262                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2263                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2264                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2265                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2266                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2267                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2268                 OPT_BOOL('c', "scissors", &state.scissors,
2269                         N_("strip everything before a scissors line")),
2270                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2271                         N_("pass it through git-apply"),
2272                         0),
2273                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2274                         N_("pass it through git-apply"),
2275                         PARSE_OPT_NOARG),
2276                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2277                         N_("pass it through git-apply"),
2278                         PARSE_OPT_NOARG),
2279                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2280                         N_("pass it through git-apply"),
2281                         0),
2282                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2283                         N_("pass it through git-apply"),
2284                         0),
2285                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2286                         N_("pass it through git-apply"),
2287                         0),
2288                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2289                         N_("pass it through git-apply"),
2290                         0),
2291                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2292                         N_("pass it through git-apply"),
2293                         0),
2294                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2295                         N_("format the patch(es) are in"),
2296                         parse_opt_patchformat),
2297                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2298                         N_("pass it through git-apply"),
2299                         PARSE_OPT_NOARG),
2300                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2301                         N_("override error message when patch failure occurs")),
2302                 OPT_CMDMODE(0, "continue", &resume,
2303                         N_("continue applying patches after resolving a conflict"),
2304                         RESUME_RESOLVED),
2305                 OPT_CMDMODE('r', "resolved", &resume,
2306                         N_("synonyms for --continue"),
2307                         RESUME_RESOLVED),
2308                 OPT_CMDMODE(0, "skip", &resume,
2309                         N_("skip the current patch"),
2310                         RESUME_SKIP),
2311                 OPT_CMDMODE(0, "abort", &resume,
2312                         N_("restore the original branch and abort the patching operation."),
2313                         RESUME_ABORT),
2314                 OPT_BOOL(0, "committer-date-is-author-date",
2315                         &state.committer_date_is_author_date,
2316                         N_("lie about committer date")),
2317                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2318                         N_("use current timestamp for author date")),
2319                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2320                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2321                   N_("GPG-sign commits"),
2322                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2323                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2324                         N_("(internal use for git-rebase)")),
2325                 OPT_END()
2326         };
2327
2328         git_config(git_am_config, NULL);
2329
2330         am_state_init(&state, git_path("rebase-apply"));
2331
2332         in_progress = am_in_progress(&state);
2333         if (in_progress)
2334                 am_load(&state);
2335
2336         argc = parse_options(argc, argv, prefix, options, usage, 0);
2337
2338         if (binary >= 0)
2339                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2340                                 "it will be removed. Please do not use it anymore."));
2341
2342         /* Ensure a valid committer ident can be constructed */
2343         git_committer_info(IDENT_STRICT);
2344
2345         if (read_index_preload(&the_index, NULL) < 0)
2346                 die(_("failed to read the index"));
2347
2348         if (in_progress) {
2349                 /*
2350                  * Catch user error to feed us patches when there is a session
2351                  * in progress:
2352                  *
2353                  * 1. mbox path(s) are provided on the command-line.
2354                  * 2. stdin is not a tty: the user is trying to feed us a patch
2355                  *    from standard input. This is somewhat unreliable -- stdin
2356                  *    could be /dev/null for example and the caller did not
2357                  *    intend to feed us a patch but wanted to continue
2358                  *    unattended.
2359                  */
2360                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2361                         die(_("previous rebase directory %s still exists but mbox given."),
2362                                 state.dir);
2363
2364                 if (resume == RESUME_FALSE)
2365                         resume = RESUME_APPLY;
2366
2367                 if (state.signoff == SIGNOFF_EXPLICIT)
2368                         am_append_signoff(&state);
2369         } else {
2370                 struct argv_array paths = ARGV_ARRAY_INIT;
2371                 int i;
2372
2373                 /*
2374                  * Handle stray state directory in the independent-run case. In
2375                  * the --rebasing case, it is up to the caller to take care of
2376                  * stray directories.
2377                  */
2378                 if (file_exists(state.dir) && !state.rebasing) {
2379                         if (resume == RESUME_ABORT) {
2380                                 am_destroy(&state);
2381                                 am_state_release(&state);
2382                                 return 0;
2383                         }
2384
2385                         die(_("Stray %s directory found.\n"
2386                                 "Use \"git am --abort\" to remove it."),
2387                                 state.dir);
2388                 }
2389
2390                 if (resume)
2391                         die(_("Resolve operation not in progress, we are not resuming."));
2392
2393                 for (i = 0; i < argc; i++) {
2394                         if (is_absolute_path(argv[i]) || !prefix)
2395                                 argv_array_push(&paths, argv[i]);
2396                         else
2397                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2398                 }
2399
2400                 am_setup(&state, patch_format, paths.argv, keep_cr);
2401
2402                 argv_array_clear(&paths);
2403         }
2404
2405         switch (resume) {
2406         case RESUME_FALSE:
2407                 am_run(&state, 0);
2408                 break;
2409         case RESUME_APPLY:
2410                 am_run(&state, 1);
2411                 break;
2412         case RESUME_RESOLVED:
2413                 am_resolve(&state);
2414                 break;
2415         case RESUME_SKIP:
2416                 am_skip(&state);
2417                 break;
2418         case RESUME_ABORT:
2419                 am_abort(&state);
2420                 break;
2421         default:
2422                 die("BUG: invalid resume value");
2423         }
2424
2425         am_state_release(&state);
2426
2427         return 0;
2428 }