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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 #include "string-list.h"
  32
  33 /**
  34  * Returns 1 if the file is empty or does not exist, 0 otherwise.
  35  */
  36 static int is_empty_file(const char *filename)
  37 {
  38         struct stat st;
  39
  40         if (stat(filename, &st) < 0) {
  41                 if (errno == ENOENT)
  42                         return 1;
  43                 die_errno(_("could not stat %s"), filename);
  44         }
  45
  46         return !st.st_size;
  47 }
  48
  49 /**
  50  * Returns the length of the first line of msg.
  51  */
  52 static int linelen(const char *msg)
  53 {
  54         return strchrnul(msg, '\n') - msg;
  55 }
  56
  57 /**
  58  * Returns true if `str` consists of only whitespace, false otherwise.
  59  */
  60 static int str_isspace(const char *str)
  61 {
  62         for (; *str; str++)
  63                 if (!isspace(*str))
  64                         return 0;
  65
  66         return 1;
  67 }
  68
  69 enum patch_format {
  70         PATCH_FORMAT_UNKNOWN = 0,
  71         PATCH_FORMAT_MBOX,
  72         PATCH_FORMAT_STGIT,
  73         PATCH_FORMAT_STGIT_SERIES,
  74         PATCH_FORMAT_HG,
  75         PATCH_FORMAT_MBOXRD
  76 };
  77
  78 enum keep_type {
  79         KEEP_FALSE = 0,
  80         KEEP_TRUE,      /* pass -k flag to git-mailinfo */
  81         KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
  82 };
  83
  84 enum scissors_type {
  85         SCISSORS_UNSET = -1,
  86         SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
  87         SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
  88 };
  89
  90 enum signoff_type {
  91         SIGNOFF_FALSE = 0,
  92         SIGNOFF_TRUE = 1,
  93         SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
  94 };
  95
  96 struct am_state {
  97         /* state directory path */
  98         char *dir;
  99
 100         /* current and last patch numbers, 1-indexed */
 101         int cur;
 102         int last;
 103
 104         /* commit metadata and message */
 105         char *author_name;
 106         char *author_email;
 107         char *author_date;
 108         char *msg;
 109         size_t msg_len;
 110
 111         /* when --rebasing, records the original commit the patch came from */
 112         unsigned char orig_commit[GIT_SHA1_RAWSZ];
 113
 114         /* number of digits in patch filename */
 115         int prec;
 116
 117         /* various operating modes and command line options */
 118         int interactive;
 119         int threeway;
 120         int quiet;
 121         int signoff; /* enum signoff_type */
 122         int utf8;
 123         int keep; /* enum keep_type */
 124         int message_id;
 125         int scissors; /* enum scissors_type */
 126         struct argv_array git_apply_opts;
 127         const char *resolvemsg;
 128         int committer_date_is_author_date;
 129         int ignore_date;
 130         int allow_rerere_autoupdate;
 131         const char *sign_commit;
 132         int rebasing;
 133 };
 134
 135 /**
 136  * Initializes am_state with the default values. The state directory is set to
 137  * dir.
 138  */
 139 static void am_state_init(struct am_state *state, const char *dir)
 140 {
 141         int gpgsign;
 142
 143         memset(state, 0, sizeof(*state));
 144
 145         assert(dir);
 146         state->dir = xstrdup(dir);
 147
 148         state->prec = 4;
 149
 150         git_config_get_bool("am.threeway", &state->threeway);
 151
 152         state->utf8 = 1;
 153
 154         git_config_get_bool("am.messageid", &state->message_id);
 155
 156         state->scissors = SCISSORS_UNSET;
 157
 158         argv_array_init(&state->git_apply_opts);
 159
 160         if (!git_config_get_bool("commit.gpgsign", &gpgsign))
 161                 state->sign_commit = gpgsign ? "" : NULL;
 162 }
 163
 164 /**
 165  * Releases memory allocated by an am_state.
 166  */
 167 static void am_state_release(struct am_state *state)
 168 {
 169         free(state->dir);
 170         free(state->author_name);
 171         free(state->author_email);
 172         free(state->author_date);
 173         free(state->msg);
 174         argv_array_clear(&state->git_apply_opts);
 175 }
 176
 177 /**
 178  * Returns path relative to the am_state directory.
 179  */
 180 static inline const char *am_path(const struct am_state *state, const char *path)
 181 {
 182         return mkpath("%s/%s", state->dir, path);
 183 }
 184
 185 /**
 186  * For convenience to call write_file()
 187  */
 188 static void write_state_text(const struct am_state *state,
 189                              const char *name, const char *string)
 190 {
 191         write_file(am_path(state, name), "%s", string);
 192 }
 193
 194 static void write_state_count(const struct am_state *state,
 195                               const char *name, int value)
 196 {
 197         write_file(am_path(state, name), "%d", value);
 198 }
 199
 200 static void write_state_bool(const struct am_state *state,
 201                              const char *name, int value)
 202 {
 203         write_state_text(state, name, value ? "t" : "f");
 204 }
 205
 206 /**
 207  * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
 208  * at the end.
 209  */
 210 static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
 211 {
 212         va_list ap;
 213
 214         va_start(ap, fmt);
 215         if (!state->quiet) {
 216                 vfprintf(fp, fmt, ap);
 217                 putc('\n', fp);
 218         }
 219         va_end(ap);
 220 }
 221
 222 /**
 223  * Returns 1 if there is an am session in progress, 0 otherwise.
 224  */
 225 static int am_in_progress(const struct am_state *state)
 226 {
 227         struct stat st;
 228
 229         if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
 230                 return 0;
 231         if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
 232                 return 0;
 233         if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
 234                 return 0;
 235         return 1;
 236 }
 237
 238 /**
 239  * Reads the contents of `file` in the `state` directory into `sb`. Returns the
 240  * number of bytes read on success, -1 if the file does not exist. If `trim` is
 241  * set, trailing whitespace will be removed.
 242  */
 243 static int read_state_file(struct strbuf *sb, const struct am_state *state,
 244                         const char *file, int trim)
 245 {
 246         strbuf_reset(sb);
 247
 248         if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
 249                 if (trim)
 250                         strbuf_trim(sb);
 251
 252                 return sb->len;
 253         }
 254
 255         if (errno == ENOENT)
 256                 return -1;
 257
 258         die_errno(_("could not read '%s'"), am_path(state, file));
 259 }
 260
 261 /**
 262  * Take a series of KEY='VALUE' lines where VALUE part is
 263  * sq-quoted, and append <KEY, VALUE> at the end of the string list
 264  */
 265 static int parse_key_value_squoted(char *buf, struct string_list *list)
 266 {
 267         while (*buf) {
 268                 struct string_list_item *item;
 269                 char *np;
 270                 char *cp = strchr(buf, '=');
 271                 if (!cp)
 272                         return -1;
 273                 np = strchrnul(cp, '\n');
 274                 *cp++ = '\0';
 275                 item = string_list_append(list, buf);
 276
 277                 buf = np + (*np == '\n');
 278                 *np = '\0';
 279                 cp = sq_dequote(cp);
 280                 if (!cp)
 281                         return -1;
 282                 item->util = xstrdup(cp);
 283         }
 284         return 0;
 285 }
 286
 287 /**
 288  * Reads and parses the state directory's "author-script" file, and sets
 289  * state->author_name, state->author_email and state->author_date accordingly.
 290  * Returns 0 on success, -1 if the file could not be parsed.
 291  *
 292  * The author script is of the format:
 293  *
 294  *      GIT_AUTHOR_NAME='$author_name'
 295  *      GIT_AUTHOR_EMAIL='$author_email'
 296  *      GIT_AUTHOR_DATE='$author_date'
 297  *
 298  * where $author_name, $author_email and $author_date are quoted. We are strict
 299  * with our parsing, as the file was meant to be eval'd in the old git-am.sh
 300  * script, and thus if the file differs from what this function expects, it is
 301  * better to bail out than to do something that the user does not expect.
 302  */
 303 static int read_author_script(struct am_state *state)
 304 {
 305         const char *filename = am_path(state, "author-script");
 306         struct strbuf buf = STRBUF_INIT;
 307         struct string_list kv = STRING_LIST_INIT_DUP;
 308         int retval = -1; /* assume failure */
 309         int fd;
 310
 311         assert(!state->author_name);
 312         assert(!state->author_email);
 313         assert(!state->author_date);
 314
 315         fd = open(filename, O_RDONLY);
 316         if (fd < 0) {
 317                 if (errno == ENOENT)
 318                         return 0;
 319                 die_errno(_("could not open '%s' for reading"), filename);
 320         }
 321         strbuf_read(&buf, fd, 0);
 322         close(fd);
 323         if (parse_key_value_squoted(buf.buf, &kv))
 324                 goto finish;
 325
 326         if (kv.nr != 3 ||
 327             strcmp(kv.items[0].string, "GIT_AUTHOR_NAME") ||
 328             strcmp(kv.items[1].string, "GIT_AUTHOR_EMAIL") ||
 329             strcmp(kv.items[2].string, "GIT_AUTHOR_DATE"))
 330                 goto finish;
 331         state->author_name = kv.items[0].util;
 332         state->author_email = kv.items[1].util;
 333         state->author_date = kv.items[2].util;
 334         retval = 0;
 335 finish:
 336         string_list_clear(&kv, !!retval);
 337         strbuf_release(&buf);
 338         return retval;
 339 }
 340
 341 /**
 342  * Saves state->author_name, state->author_email and state->author_date in the
 343  * state directory's "author-script" file.
 344  */
 345 static void write_author_script(const struct am_state *state)
 346 {
 347         struct strbuf sb = STRBUF_INIT;
 348
 349         strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
 350         sq_quote_buf(&sb, state->author_name);
 351         strbuf_addch(&sb, '\n');
 352
 353         strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
 354         sq_quote_buf(&sb, state->author_email);
 355         strbuf_addch(&sb, '\n');
 356
 357         strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
 358         sq_quote_buf(&sb, state->author_date);
 359         strbuf_addch(&sb, '\n');
 360
 361         write_state_text(state, "author-script", sb.buf);
 362
 363         strbuf_release(&sb);
 364 }
 365
 366 /**
 367  * Reads the commit message from the state directory's "final-commit" file,
 368  * setting state->msg to its contents and state->msg_len to the length of its
 369  * contents in bytes.
 370  *
 371  * Returns 0 on success, -1 if the file does not exist.
 372  */
 373 static int read_commit_msg(struct am_state *state)
 374 {
 375         struct strbuf sb = STRBUF_INIT;
 376
 377         assert(!state->msg);
 378
 379         if (read_state_file(&sb, state, "final-commit", 0) < 0) {
 380                 strbuf_release(&sb);
 381                 return -1;
 382         }
 383
 384         state->msg = strbuf_detach(&sb, &state->msg_len);
 385         return 0;
 386 }
 387
 388 /**
 389  * Saves state->msg in the state directory's "final-commit" file.
 390  */
 391 static void write_commit_msg(const struct am_state *state)
 392 {
 393         const char *filename = am_path(state, "final-commit");
 394         write_file_buf(filename, state->msg, state->msg_len);
 395 }
 396
 397 /**
 398  * Loads state from disk.
 399  */
 400 static void am_load(struct am_state *state)
 401 {
 402         struct strbuf sb = STRBUF_INIT;
 403
 404         if (read_state_file(&sb, state, "next", 1) < 0)
 405                 die("BUG: state file 'next' does not exist");
 406         state->cur = strtol(sb.buf, NULL, 10);
 407
 408         if (read_state_file(&sb, state, "last", 1) < 0)
 409                 die("BUG: state file 'last' does not exist");
 410         state->last = strtol(sb.buf, NULL, 10);
 411
 412         if (read_author_script(state) < 0)
 413                 die(_("could not parse author script"));
 414
 415         read_commit_msg(state);
 416
 417         if (read_state_file(&sb, state, "original-commit", 1) < 0)
 418                 hashclr(state->orig_commit);
 419         else if (get_sha1_hex(sb.buf, state->orig_commit) < 0)
 420                 die(_("could not parse %s"), am_path(state, "original-commit"));
 421
 422         read_state_file(&sb, state, "threeway", 1);
 423         state->threeway = !strcmp(sb.buf, "t");
 424
 425         read_state_file(&sb, state, "quiet", 1);
 426         state->quiet = !strcmp(sb.buf, "t");
 427
 428         read_state_file(&sb, state, "sign", 1);
 429         state->signoff = !strcmp(sb.buf, "t");
 430
 431         read_state_file(&sb, state, "utf8", 1);
 432         state->utf8 = !strcmp(sb.buf, "t");
 433
 434         read_state_file(&sb, state, "keep", 1);
 435         if (!strcmp(sb.buf, "t"))
 436                 state->keep = KEEP_TRUE;
 437         else if (!strcmp(sb.buf, "b"))
 438                 state->keep = KEEP_NON_PATCH;
 439         else
 440                 state->keep = KEEP_FALSE;
 441
 442         read_state_file(&sb, state, "messageid", 1);
 443         state->message_id = !strcmp(sb.buf, "t");
 444
 445         read_state_file(&sb, state, "scissors", 1);
 446         if (!strcmp(sb.buf, "t"))
 447                 state->scissors = SCISSORS_TRUE;
 448         else if (!strcmp(sb.buf, "f"))
 449                 state->scissors = SCISSORS_FALSE;
 450         else
 451                 state->scissors = SCISSORS_UNSET;
 452
 453         read_state_file(&sb, state, "apply-opt", 1);
 454         argv_array_clear(&state->git_apply_opts);
 455         if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
 456                 die(_("could not parse %s"), am_path(state, "apply-opt"));
 457
 458         state->rebasing = !!file_exists(am_path(state, "rebasing"));
 459
 460         strbuf_release(&sb);
 461 }
 462
 463 /**
 464  * Removes the am_state directory, forcefully terminating the current am
 465  * session.
 466  */
 467 static void am_destroy(const struct am_state *state)
 468 {
 469         struct strbuf sb = STRBUF_INIT;
 470
 471         strbuf_addstr(&sb, state->dir);
 472         remove_dir_recursively(&sb, 0);
 473         strbuf_release(&sb);
 474 }
 475
 476 /**
 477  * Runs applypatch-msg hook. Returns its exit code.
 478  */
 479 static int run_applypatch_msg_hook(struct am_state *state)
 480 {
 481         int ret;
 482
 483         assert(state->msg);
 484         ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
 485
 486         if (!ret) {
 487                 free(state->msg);
 488                 state->msg = NULL;
 489                 if (read_commit_msg(state) < 0)
 490                         die(_("'%s' was deleted by the applypatch-msg hook"),
 491                                 am_path(state, "final-commit"));
 492         }
 493
 494         return ret;
 495 }
 496
 497 /**
 498  * Runs post-rewrite hook. Returns it exit code.
 499  */
 500 static int run_post_rewrite_hook(const struct am_state *state)
 501 {
 502         struct child_process cp = CHILD_PROCESS_INIT;
 503         const char *hook = find_hook("post-rewrite");
 504         int ret;
 505
 506         if (!hook)
 507                 return 0;
 508
 509         argv_array_push(&cp.args, hook);
 510         argv_array_push(&cp.args, "rebase");
 511
 512         cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
 513         cp.stdout_to_stderr = 1;
 514
 515         ret = run_command(&cp);
 516
 517         close(cp.in);
 518         return ret;
 519 }
 520
 521 /**
 522  * Reads the state directory's "rewritten" file, and copies notes from the old
 523  * commits listed in the file to their rewritten commits.
 524  *
 525  * Returns 0 on success, -1 on failure.
 526  */
 527 static int copy_notes_for_rebase(const struct am_state *state)
 528 {
 529         struct notes_rewrite_cfg *c;
 530         struct strbuf sb = STRBUF_INIT;
 531         const char *invalid_line = _("Malformed input line: '%s'.");
 532         const char *msg = "Notes added by 'git rebase'";
 533         FILE *fp;
 534         int ret = 0;
 535
 536         assert(state->rebasing);
 537
 538         c = init_copy_notes_for_rewrite("rebase");
 539         if (!c)
 540                 return 0;
 541
 542         fp = xfopen(am_path(state, "rewritten"), "r");
 543
 544         while (!strbuf_getline_lf(&sb, fp)) {
 545                 unsigned char from_obj[GIT_SHA1_RAWSZ], to_obj[GIT_SHA1_RAWSZ];
 546
 547                 if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
 548                         ret = error(invalid_line, sb.buf);
 549                         goto finish;
 550                 }
 551
 552                 if (get_sha1_hex(sb.buf, from_obj)) {
 553                         ret = error(invalid_line, sb.buf);
 554                         goto finish;
 555                 }
 556
 557                 if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
 558                         ret = error(invalid_line, sb.buf);
 559                         goto finish;
 560                 }
 561
 562                 if (get_sha1_hex(sb.buf + GIT_SHA1_HEXSZ + 1, to_obj)) {
 563                         ret = error(invalid_line, sb.buf);
 564                         goto finish;
 565                 }
 566
 567                 if (copy_note_for_rewrite(c, from_obj, to_obj))
 568                         ret = error(_("Failed to copy notes from '%s' to '%s'"),
 569                                         sha1_to_hex(from_obj), sha1_to_hex(to_obj));
 570         }
 571
 572 finish:
 573         finish_copy_notes_for_rewrite(c, msg);
 574         fclose(fp);
 575         strbuf_release(&sb);
 576         return ret;
 577 }
 578
 579 /**
 580  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
 581  * non-indented lines and checking if they look like they begin with valid
 582  * header field names.
 583  *
 584  * Returns 1 if the file looks like a piece of mail, 0 otherwise.
 585  */
 586 static int is_mail(FILE *fp)
 587 {
 588         const char *header_regex = "^[!-9;-~]+:";
 589         struct strbuf sb = STRBUF_INIT;
 590         regex_t regex;
 591         int ret = 1;
 592
 593         if (fseek(fp, 0L, SEEK_SET))
 594                 die_errno(_("fseek failed"));
 595
 596         if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
 597                 die("invalid pattern: %s", header_regex);
 598
 599         while (!strbuf_getline(&sb, fp)) {
 600                 if (!sb.len)
 601                         break; /* End of header */
 602
 603                 /* Ignore indented folded lines */
 604                 if (*sb.buf == '\t' || *sb.buf == ' ')
 605                         continue;
 606
 607                 /* It's a header if it matches header_regex */
 608                 if (regexec(&regex, sb.buf, 0, NULL, 0)) {
 609                         ret = 0;
 610                         goto done;
 611                 }
 612         }
 613
 614 done:
 615         regfree(&regex);
 616         strbuf_release(&sb);
 617         return ret;
 618 }
 619
 620 /**
 621  * Attempts to detect the patch_format of the patches contained in `paths`,
 622  * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
 623  * detection fails.
 624  */
 625 static int detect_patch_format(const char **paths)
 626 {
 627         enum patch_format ret = PATCH_FORMAT_UNKNOWN;
 628         struct strbuf l1 = STRBUF_INIT;
 629         struct strbuf l2 = STRBUF_INIT;
 630         struct strbuf l3 = STRBUF_INIT;
 631         FILE *fp;
 632
 633         /*
 634          * We default to mbox format if input is from stdin and for directories
 635          */
 636         if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
 637                 return PATCH_FORMAT_MBOX;
 638
 639         /*
 640          * Otherwise, check the first few lines of the first patch, starting
 641          * from the first non-blank line, to try to detect its format.
 642          */
 643
 644         fp = xfopen(*paths, "r");
 645
 646         while (!strbuf_getline(&l1, fp)) {
 647                 if (l1.len)
 648                         break;
 649         }
 650
 651         if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
 652                 ret = PATCH_FORMAT_MBOX;
 653                 goto done;
 654         }
 655
 656         if (starts_with(l1.buf, "# This series applies on GIT commit")) {
 657                 ret = PATCH_FORMAT_STGIT_SERIES;
 658                 goto done;
 659         }
 660
 661         if (!strcmp(l1.buf, "# HG changeset patch")) {
 662                 ret = PATCH_FORMAT_HG;
 663                 goto done;
 664         }
 665
 666         strbuf_reset(&l2);
 667         strbuf_getline(&l2, fp);
 668         strbuf_reset(&l3);
 669         strbuf_getline(&l3, fp);
 670
 671         /*
 672          * If the second line is empty and the third is a From, Author or Date
 673          * entry, this is likely an StGit patch.
 674          */
 675         if (l1.len && !l2.len &&
 676                 (starts_with(l3.buf, "From:") ||
 677                  starts_with(l3.buf, "Author:") ||
 678                  starts_with(l3.buf, "Date:"))) {
 679                 ret = PATCH_FORMAT_STGIT;
 680                 goto done;
 681         }
 682
 683         if (l1.len && is_mail(fp)) {
 684                 ret = PATCH_FORMAT_MBOX;
 685                 goto done;
 686         }
 687
 688 done:
 689         fclose(fp);
 690         strbuf_release(&l1);
 691         return ret;
 692 }
 693
 694 /**
 695  * Splits out individual email patches from `paths`, where each path is either
 696  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
 697  */
 698 static int split_mail_mbox(struct am_state *state, const char **paths,
 699                                 int keep_cr, int mboxrd)
 700 {
 701         struct child_process cp = CHILD_PROCESS_INIT;
 702         struct strbuf last = STRBUF_INIT;
 703
 704         cp.git_cmd = 1;
 705         argv_array_push(&cp.args, "mailsplit");
 706         argv_array_pushf(&cp.args, "-d%d", state->prec);
 707         argv_array_pushf(&cp.args, "-o%s", state->dir);
 708         argv_array_push(&cp.args, "-b");
 709         if (keep_cr)
 710                 argv_array_push(&cp.args, "--keep-cr");
 711         if (mboxrd)
 712                 argv_array_push(&cp.args, "--mboxrd");
 713         argv_array_push(&cp.args, "--");
 714         argv_array_pushv(&cp.args, paths);
 715
 716         if (capture_command(&cp, &last, 8))
 717                 return -1;
 718
 719         state->cur = 1;
 720         state->last = strtol(last.buf, NULL, 10);
 721
 722         return 0;
 723 }
 724
 725 /**
 726  * Callback signature for split_mail_conv(). The foreign patch should be
 727  * read from `in`, and the converted patch (in RFC2822 mail format) should be
 728  * written to `out`. Return 0 on success, or -1 on failure.
 729  */
 730 typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
 731
 732 /**
 733  * Calls `fn` for each file in `paths` to convert the foreign patch to the
 734  * RFC2822 mail format suitable for parsing with git-mailinfo.
 735  *
 736  * Returns 0 on success, -1 on failure.
 737  */
 738 static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
 739                         const char **paths, int keep_cr)
 740 {
 741         static const char *stdin_only[] = {"-", NULL};
 742         int i;
 743
 744         if (!*paths)
 745                 paths = stdin_only;
 746
 747         for (i = 0; *paths; paths++, i++) {
 748                 FILE *in, *out;
 749                 const char *mail;
 750                 int ret;
 751
 752                 if (!strcmp(*paths, "-"))
 753                         in = stdin;
 754                 else
 755                         in = fopen(*paths, "r");
 756
 757                 if (!in)
 758                         return error_errno(_("could not open '%s' for reading"),
 759                                            *paths);
 760
 761                 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 762
 763                 out = fopen(mail, "w");
 764                 if (!out)
 765                         return error_errno(_("could not open '%s' for writing"),
 766                                            mail);
 767
 768                 ret = fn(out, in, keep_cr);
 769
 770                 fclose(out);
 771                 fclose(in);
 772
 773                 if (ret)
 774                         return error(_("could not parse patch '%s'"), *paths);
 775         }
 776
 777         state->cur = 1;
 778         state->last = i;
 779         return 0;
 780 }
 781
 782 /**
 783  * A split_mail_conv() callback that converts an StGit patch to an RFC2822
 784  * message suitable for parsing with git-mailinfo.
 785  */
 786 static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 787 {
 788         struct strbuf sb = STRBUF_INIT;
 789         int subject_printed = 0;
 790
 791         while (!strbuf_getline_lf(&sb, in)) {
 792                 const char *str;
 793
 794                 if (str_isspace(sb.buf))
 795                         continue;
 796                 else if (skip_prefix(sb.buf, "Author:", &str))
 797                         fprintf(out, "From:%s\n", str);
 798                 else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
 799                         fprintf(out, "%s\n", sb.buf);
 800                 else if (!subject_printed) {
 801                         fprintf(out, "Subject: %s\n", sb.buf);
 802                         subject_printed = 1;
 803                 } else {
 804                         fprintf(out, "\n%s\n", sb.buf);
 805                         break;
 806                 }
 807         }
 808
 809         strbuf_reset(&sb);
 810         while (strbuf_fread(&sb, 8192, in) > 0) {
 811                 fwrite(sb.buf, 1, sb.len, out);
 812                 strbuf_reset(&sb);
 813         }
 814
 815         strbuf_release(&sb);
 816         return 0;
 817 }
 818
 819 /**
 820  * This function only supports a single StGit series file in `paths`.
 821  *
 822  * Given an StGit series file, converts the StGit patches in the series into
 823  * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
 824  * the state directory.
 825  *
 826  * Returns 0 on success, -1 on failure.
 827  */
 828 static int split_mail_stgit_series(struct am_state *state, const char **paths,
 829                                         int keep_cr)
 830 {
 831         const char *series_dir;
 832         char *series_dir_buf;
 833         FILE *fp;
 834         struct argv_array patches = ARGV_ARRAY_INIT;
 835         struct strbuf sb = STRBUF_INIT;
 836         int ret;
 837
 838         if (!paths[0] || paths[1])
 839                 return error(_("Only one StGIT patch series can be applied at once"));
 840
 841         series_dir_buf = xstrdup(*paths);
 842         series_dir = dirname(series_dir_buf);
 843
 844         fp = fopen(*paths, "r");
 845         if (!fp)
 846                 return error_errno(_("could not open '%s' for reading"), *paths);
 847
 848         while (!strbuf_getline_lf(&sb, fp)) {
 849                 if (*sb.buf == '#')
 850                         continue; /* skip comment lines */
 851
 852                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
 853         }
 854
 855         fclose(fp);
 856         strbuf_release(&sb);
 857         free(series_dir_buf);
 858
 859         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
 860
 861         argv_array_clear(&patches);
 862         return ret;
 863 }
 864
 865 /**
 866  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
 867  * message suitable for parsing with git-mailinfo.
 868  */
 869 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 870 {
 871         struct strbuf sb = STRBUF_INIT;
 872
 873         while (!strbuf_getline_lf(&sb, in)) {
 874                 const char *str;
 875
 876                 if (skip_prefix(sb.buf, "# User ", &str))
 877                         fprintf(out, "From: %s\n", str);
 878                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
 879                         unsigned long timestamp;
 880                         long tz, tz2;
 881                         char *end;
 882
 883                         errno = 0;
 884                         timestamp = strtoul(str, &end, 10);
 885                         if (errno)
 886                                 return error(_("invalid timestamp"));
 887
 888                         if (!skip_prefix(end, " ", &str))
 889                                 return error(_("invalid Date line"));
 890
 891                         errno = 0;
 892                         tz = strtol(str, &end, 10);
 893                         if (errno)
 894                                 return error(_("invalid timezone offset"));
 895
 896                         if (*end)
 897                                 return error(_("invalid Date line"));
 898
 899                         /*
 900                          * mercurial's timezone is in seconds west of UTC,
 901                          * however git's timezone is in hours + minutes east of
 902                          * UTC. Convert it.
 903                          */
 904                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
 905                         if (tz > 0)
 906                                 tz2 = -tz2;
 907
 908                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
 909                 } else if (starts_with(sb.buf, "# ")) {
 910                         continue;
 911                 } else {
 912                         fprintf(out, "\n%s\n", sb.buf);
 913                         break;
 914                 }
 915         }
 916
 917         strbuf_reset(&sb);
 918         while (strbuf_fread(&sb, 8192, in) > 0) {
 919                 fwrite(sb.buf, 1, sb.len, out);
 920                 strbuf_reset(&sb);
 921         }
 922
 923         strbuf_release(&sb);
 924         return 0;
 925 }
 926
 927 /**
 928  * Splits a list of files/directories into individual email patches. Each path
 929  * in `paths` must be a file/directory that is formatted according to
 930  * `patch_format`.
 931  *
 932  * Once split out, the individual email patches will be stored in the state
 933  * directory, with each patch's filename being its index, padded to state->prec
 934  * digits.
 935  *
 936  * state->cur will be set to the index of the first mail, and state->last will
 937  * be set to the index of the last mail.
 938  *
 939  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
 940  * to disable this behavior, -1 to use the default configured setting.
 941  *
 942  * Returns 0 on success, -1 on failure.
 943  */
 944 static int split_mail(struct am_state *state, enum patch_format patch_format,
 945                         const char **paths, int keep_cr)
 946 {
 947         if (keep_cr < 0) {
 948                 keep_cr = 0;
 949                 git_config_get_bool("am.keepcr", &keep_cr);
 950         }
 951
 952         switch (patch_format) {
 953         case PATCH_FORMAT_MBOX:
 954                 return split_mail_mbox(state, paths, keep_cr, 0);
 955         case PATCH_FORMAT_STGIT:
 956                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 957         case PATCH_FORMAT_STGIT_SERIES:
 958                 return split_mail_stgit_series(state, paths, keep_cr);
 959         case PATCH_FORMAT_HG:
 960                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
 961         case PATCH_FORMAT_MBOXRD:
 962                 return split_mail_mbox(state, paths, keep_cr, 1);
 963         default:
 964                 die("BUG: invalid patch_format");
 965         }
 966         return -1;
 967 }
 968
 969 /**
 970  * Setup a new am session for applying patches
 971  */
 972 static void am_setup(struct am_state *state, enum patch_format patch_format,
 973                         const char **paths, int keep_cr)
 974 {
 975         unsigned char curr_head[GIT_SHA1_RAWSZ];
 976         const char *str;
 977         struct strbuf sb = STRBUF_INIT;
 978
 979         if (!patch_format)
 980                 patch_format = detect_patch_format(paths);
 981
 982         if (!patch_format) {
 983                 fprintf_ln(stderr, _("Patch format detection failed."));
 984                 exit(128);
 985         }
 986
 987         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 988                 die_errno(_("failed to create directory '%s'"), state->dir);
 989
 990         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
 991                 am_destroy(state);
 992                 die(_("Failed to split patches."));
 993         }
 994
 995         if (state->rebasing)
 996                 state->threeway = 1;
 997
 998         write_state_bool(state, "threeway", state->threeway);
 999         write_state_bool(state, "quiet", state->quiet);
1000         write_state_bool(state, "sign", state->signoff);
1001         write_state_bool(state, "utf8", state->utf8);
1002
1003         switch (state->keep) {
1004         case KEEP_FALSE:
1005                 str = "f";
1006                 break;
1007         case KEEP_TRUE:
1008                 str = "t";
1009                 break;
1010         case KEEP_NON_PATCH:
1011                 str = "b";
1012                 break;
1013         default:
1014                 die("BUG: invalid value for state->keep");
1015         }
1016
1017         write_state_text(state, "keep", str);
1018         write_state_bool(state, "messageid", state->message_id);
1019
1020         switch (state->scissors) {
1021         case SCISSORS_UNSET:
1022                 str = "";
1023                 break;
1024         case SCISSORS_FALSE:
1025                 str = "f";
1026                 break;
1027         case SCISSORS_TRUE:
1028                 str = "t";
1029                 break;
1030         default:
1031                 die("BUG: invalid value for state->scissors");
1032         }
1033         write_state_text(state, "scissors", str);
1034
1035         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1036         write_state_text(state, "apply-opt", sb.buf);
1037
1038         if (state->rebasing)
1039                 write_state_text(state, "rebasing", "");
1040         else
1041                 write_state_text(state, "applying", "");
1042
1043         if (!get_sha1("HEAD", curr_head)) {
1044                 write_state_text(state, "abort-safety", sha1_to_hex(curr_head));
1045                 if (!state->rebasing)
1046                         update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
1047                                         UPDATE_REFS_DIE_ON_ERR);
1048         } else {
1049                 write_state_text(state, "abort-safety", "");
1050                 if (!state->rebasing)
1051                         delete_ref("ORIG_HEAD", NULL, 0);
1052         }
1053
1054         /*
1055          * NOTE: Since the "next" and "last" files determine if an am_state
1056          * session is in progress, they should be written last.
1057          */
1058
1059         write_state_count(state, "next", state->cur);
1060         write_state_count(state, "last", state->last);
1061
1062         strbuf_release(&sb);
1063 }
1064
1065 /**
1066  * Increments the patch pointer, and cleans am_state for the application of the
1067  * next patch.
1068  */
1069 static void am_next(struct am_state *state)
1070 {
1071         unsigned char head[GIT_SHA1_RAWSZ];
1072
1073         free(state->author_name);
1074         state->author_name = NULL;
1075
1076         free(state->author_email);
1077         state->author_email = NULL;
1078
1079         free(state->author_date);
1080         state->author_date = NULL;
1081
1082         free(state->msg);
1083         state->msg = NULL;
1084         state->msg_len = 0;
1085
1086         unlink(am_path(state, "author-script"));
1087         unlink(am_path(state, "final-commit"));
1088
1089         hashclr(state->orig_commit);
1090         unlink(am_path(state, "original-commit"));
1091
1092         if (!get_sha1("HEAD", head))
1093                 write_state_text(state, "abort-safety", sha1_to_hex(head));
1094         else
1095                 write_state_text(state, "abort-safety", "");
1096
1097         state->cur++;
1098         write_state_count(state, "next", state->cur);
1099 }
1100
1101 /**
1102  * Returns the filename of the current patch email.
1103  */
1104 static const char *msgnum(const struct am_state *state)
1105 {
1106         static struct strbuf sb = STRBUF_INIT;
1107
1108         strbuf_reset(&sb);
1109         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1110
1111         return sb.buf;
1112 }
1113
1114 /**
1115  * Refresh and write index.
1116  */
1117 static void refresh_and_write_cache(void)
1118 {
1119         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1120
1121         hold_locked_index(lock_file, 1);
1122         refresh_cache(REFRESH_QUIET);
1123         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1124                 die(_("unable to write index file"));
1125 }
1126
1127 /**
1128  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1129  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1130  * strbuf is provided, the space-separated list of files that differ will be
1131  * appended to it.
1132  */
1133 static int index_has_changes(struct strbuf *sb)
1134 {
1135         unsigned char head[GIT_SHA1_RAWSZ];
1136         int i;
1137
1138         if (!get_sha1_tree("HEAD", head)) {
1139                 struct diff_options opt;
1140
1141                 diff_setup(&opt);
1142                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1143                 if (!sb)
1144                         DIFF_OPT_SET(&opt, QUICK);
1145                 do_diff_cache(head, &opt);
1146                 diffcore_std(&opt);
1147                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1148                         if (i)
1149                                 strbuf_addch(sb, ' ');
1150                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1151                 }
1152                 diff_flush(&opt);
1153                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1154         } else {
1155                 for (i = 0; sb && i < active_nr; i++) {
1156                         if (i)
1157                                 strbuf_addch(sb, ' ');
1158                         strbuf_addstr(sb, active_cache[i]->name);
1159                 }
1160                 return !!active_nr;
1161         }
1162 }
1163
1164 /**
1165  * Dies with a user-friendly message on how to proceed after resolving the
1166  * problem. This message can be overridden with state->resolvemsg.
1167  */
1168 static void NORETURN die_user_resolve(const struct am_state *state)
1169 {
1170         if (state->resolvemsg) {
1171                 printf_ln("%s", state->resolvemsg);
1172         } else {
1173                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1174
1175                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1176                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1177                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1178         }
1179
1180         exit(128);
1181 }
1182
1183 static void am_signoff(struct strbuf *sb)
1184 {
1185         char *cp;
1186         struct strbuf mine = STRBUF_INIT;
1187
1188         /* Does it end with our own sign-off? */
1189         strbuf_addf(&mine, "\n%s%s\n",
1190                     sign_off_header,
1191                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1192                              getenv("GIT_COMMITTER_EMAIL")));
1193         if (mine.len < sb->len &&
1194             !strcmp(mine.buf, sb->buf + sb->len - mine.len))
1195                 goto exit; /* no need to duplicate */
1196
1197         /* Does it have any Signed-off-by: in the text */
1198         for (cp = sb->buf;
1199              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1200              cp = strchr(cp, '\n')) {
1201                 if (sb->buf == cp || cp[-1] == '\n')
1202                         break;
1203         }
1204
1205         strbuf_addstr(sb, mine.buf + !!cp);
1206 exit:
1207         strbuf_release(&mine);
1208 }
1209
1210 /**
1211  * Appends signoff to the "msg" field of the am_state.
1212  */
1213 static void am_append_signoff(struct am_state *state)
1214 {
1215         struct strbuf sb = STRBUF_INIT;
1216
1217         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1218         am_signoff(&sb);
1219         state->msg = strbuf_detach(&sb, &state->msg_len);
1220 }
1221
1222 /**
1223  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1224  * state->msg will be set to the patch message. state->author_name,
1225  * state->author_email and state->author_date will be set to the patch author's
1226  * name, email and date respectively. The patch body will be written to the
1227  * state directory's "patch" file.
1228  *
1229  * Returns 1 if the patch should be skipped, 0 otherwise.
1230  */
1231 static int parse_mail(struct am_state *state, const char *mail)
1232 {
1233         FILE *fp;
1234         struct strbuf sb = STRBUF_INIT;
1235         struct strbuf msg = STRBUF_INIT;
1236         struct strbuf author_name = STRBUF_INIT;
1237         struct strbuf author_date = STRBUF_INIT;
1238         struct strbuf author_email = STRBUF_INIT;
1239         int ret = 0;
1240         struct mailinfo mi;
1241
1242         setup_mailinfo(&mi);
1243
1244         if (state->utf8)
1245                 mi.metainfo_charset = get_commit_output_encoding();
1246         else
1247                 mi.metainfo_charset = NULL;
1248
1249         switch (state->keep) {
1250         case KEEP_FALSE:
1251                 break;
1252         case KEEP_TRUE:
1253                 mi.keep_subject = 1;
1254                 break;
1255         case KEEP_NON_PATCH:
1256                 mi.keep_non_patch_brackets_in_subject = 1;
1257                 break;
1258         default:
1259                 die("BUG: invalid value for state->keep");
1260         }
1261
1262         if (state->message_id)
1263                 mi.add_message_id = 1;
1264
1265         switch (state->scissors) {
1266         case SCISSORS_UNSET:
1267                 break;
1268         case SCISSORS_FALSE:
1269                 mi.use_scissors = 0;
1270                 break;
1271         case SCISSORS_TRUE:
1272                 mi.use_scissors = 1;
1273                 break;
1274         default:
1275                 die("BUG: invalid value for state->scissors");
1276         }
1277
1278         mi.input = fopen(mail, "r");
1279         if (!mi.input)
1280                 die("could not open input");
1281         mi.output = fopen(am_path(state, "info"), "w");
1282         if (!mi.output)
1283                 die("could not open output 'info'");
1284         if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
1285                 die("could not parse patch");
1286
1287         fclose(mi.input);
1288         fclose(mi.output);
1289
1290         /* Extract message and author information */
1291         fp = xfopen(am_path(state, "info"), "r");
1292         while (!strbuf_getline_lf(&sb, fp)) {
1293                 const char *x;
1294
1295                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1296                         if (msg.len)
1297                                 strbuf_addch(&msg, '\n');
1298                         strbuf_addstr(&msg, x);
1299                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1300                         strbuf_addstr(&author_name, x);
1301                 else if (skip_prefix(sb.buf, "Email: ", &x))
1302                         strbuf_addstr(&author_email, x);
1303                 else if (skip_prefix(sb.buf, "Date: ", &x))
1304                         strbuf_addstr(&author_date, x);
1305         }
1306         fclose(fp);
1307
1308         /* Skip pine's internal folder data */
1309         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1310                 ret = 1;
1311                 goto finish;
1312         }
1313
1314         if (is_empty_file(am_path(state, "patch"))) {
1315                 printf_ln(_("Patch is empty. Was it split wrong?"));
1316                 die_user_resolve(state);
1317         }
1318
1319         strbuf_addstr(&msg, "\n\n");
1320         strbuf_addbuf(&msg, &mi.log_message);
1321         strbuf_stripspace(&msg, 0);
1322
1323         if (state->signoff)
1324                 am_signoff(&msg);
1325
1326         assert(!state->author_name);
1327         state->author_name = strbuf_detach(&author_name, NULL);
1328
1329         assert(!state->author_email);
1330         state->author_email = strbuf_detach(&author_email, NULL);
1331
1332         assert(!state->author_date);
1333         state->author_date = strbuf_detach(&author_date, NULL);
1334
1335         assert(!state->msg);
1336         state->msg = strbuf_detach(&msg, &state->msg_len);
1337
1338 finish:
1339         strbuf_release(&msg);
1340         strbuf_release(&author_date);
1341         strbuf_release(&author_email);
1342         strbuf_release(&author_name);
1343         strbuf_release(&sb);
1344         clear_mailinfo(&mi);
1345         return ret;
1346 }
1347
1348 /**
1349  * Sets commit_id to the commit hash where the mail was generated from.
1350  * Returns 0 on success, -1 on failure.
1351  */
1352 static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
1353 {
1354         struct strbuf sb = STRBUF_INIT;
1355         FILE *fp = xfopen(mail, "r");
1356         const char *x;
1357
1358         if (strbuf_getline_lf(&sb, fp))
1359                 return -1;
1360
1361         if (!skip_prefix(sb.buf, "From ", &x))
1362                 return -1;
1363
1364         if (get_sha1_hex(x, commit_id) < 0)
1365                 return -1;
1366
1367         strbuf_release(&sb);
1368         fclose(fp);
1369         return 0;
1370 }
1371
1372 /**
1373  * Sets state->msg, state->author_name, state->author_email, state->author_date
1374  * to the commit's respective info.
1375  */
1376 static void get_commit_info(struct am_state *state, struct commit *commit)
1377 {
1378         const char *buffer, *ident_line, *author_date, *msg;
1379         size_t ident_len;
1380         struct ident_split ident_split;
1381         struct strbuf sb = STRBUF_INIT;
1382
1383         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1384
1385         ident_line = find_commit_header(buffer, "author", &ident_len);
1386
1387         if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
1388                 strbuf_add(&sb, ident_line, ident_len);
1389                 die(_("invalid ident line: %s"), sb.buf);
1390         }
1391
1392         assert(!state->author_name);
1393         if (ident_split.name_begin) {
1394                 strbuf_add(&sb, ident_split.name_begin,
1395                         ident_split.name_end - ident_split.name_begin);
1396                 state->author_name = strbuf_detach(&sb, NULL);
1397         } else
1398                 state->author_name = xstrdup("");
1399
1400         assert(!state->author_email);
1401         if (ident_split.mail_begin) {
1402                 strbuf_add(&sb, ident_split.mail_begin,
1403                         ident_split.mail_end - ident_split.mail_begin);
1404                 state->author_email = strbuf_detach(&sb, NULL);
1405         } else
1406                 state->author_email = xstrdup("");
1407
1408         author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
1409         strbuf_addstr(&sb, author_date);
1410         assert(!state->author_date);
1411         state->author_date = strbuf_detach(&sb, NULL);
1412
1413         assert(!state->msg);
1414         msg = strstr(buffer, "\n\n");
1415         if (!msg)
1416                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1417         state->msg = xstrdup(msg + 2);
1418         state->msg_len = strlen(state->msg);
1419 }
1420
1421 /**
1422  * Writes `commit` as a patch to the state directory's "patch" file.
1423  */
1424 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1425 {
1426         struct rev_info rev_info;
1427         FILE *fp;
1428
1429         fp = xfopen(am_path(state, "patch"), "w");
1430         init_revisions(&rev_info, NULL);
1431         rev_info.diff = 1;
1432         rev_info.abbrev = 0;
1433         rev_info.disable_stdin = 1;
1434         rev_info.show_root_diff = 1;
1435         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1436         rev_info.no_commit_id = 1;
1437         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1438         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1439         rev_info.diffopt.use_color = 0;
1440         rev_info.diffopt.file = fp;
1441         rev_info.diffopt.close_file = 1;
1442         add_pending_object(&rev_info, &commit->object, "");
1443         diff_setup_done(&rev_info.diffopt);
1444         log_tree_commit(&rev_info, commit);
1445 }
1446
1447 /**
1448  * Writes the diff of the index against HEAD as a patch to the state
1449  * directory's "patch" file.
1450  */
1451 static void write_index_patch(const struct am_state *state)
1452 {
1453         struct tree *tree;
1454         unsigned char head[GIT_SHA1_RAWSZ];
1455         struct rev_info rev_info;
1456         FILE *fp;
1457
1458         if (!get_sha1_tree("HEAD", head))
1459                 tree = lookup_tree(head);
1460         else
1461                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1462
1463         fp = xfopen(am_path(state, "patch"), "w");
1464         init_revisions(&rev_info, NULL);
1465         rev_info.diff = 1;
1466         rev_info.disable_stdin = 1;
1467         rev_info.no_commit_id = 1;
1468         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1469         rev_info.diffopt.use_color = 0;
1470         rev_info.diffopt.file = fp;
1471         rev_info.diffopt.close_file = 1;
1472         add_pending_object(&rev_info, &tree->object, "");
1473         diff_setup_done(&rev_info.diffopt);
1474         run_diff_index(&rev_info, 1);
1475 }
1476
1477 /**
1478  * Like parse_mail(), but parses the mail by looking up its commit ID
1479  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1480  * of patches.
1481  *
1482  * state->orig_commit will be set to the original commit ID.
1483  *
1484  * Will always return 0 as the patch should never be skipped.
1485  */
1486 static int parse_mail_rebase(struct am_state *state, const char *mail)
1487 {
1488         struct commit *commit;
1489         unsigned char commit_sha1[GIT_SHA1_RAWSZ];
1490
1491         if (get_mail_commit_sha1(commit_sha1, mail) < 0)
1492                 die(_("could not parse %s"), mail);
1493
1494         commit = lookup_commit_or_die(commit_sha1, mail);
1495
1496         get_commit_info(state, commit);
1497
1498         write_commit_patch(state, commit);
1499
1500         hashcpy(state->orig_commit, commit_sha1);
1501         write_state_text(state, "original-commit", sha1_to_hex(commit_sha1));
1502
1503         return 0;
1504 }
1505
1506 /**
1507  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1508  * `index_file` is not NULL, the patch will be applied to that index.
1509  */
1510 static int run_apply(const struct am_state *state, const char *index_file)
1511 {
1512         struct child_process cp = CHILD_PROCESS_INIT;
1513
1514         cp.git_cmd = 1;
1515
1516         if (index_file)
1517                 argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
1518
1519         /*
1520          * If we are allowed to fall back on 3-way merge, don't give false
1521          * errors during the initial attempt.
1522          */
1523         if (state->threeway && !index_file) {
1524                 cp.no_stdout = 1;
1525                 cp.no_stderr = 1;
1526         }
1527
1528         argv_array_push(&cp.args, "apply");
1529
1530         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1531
1532         if (index_file)
1533                 argv_array_push(&cp.args, "--cached");
1534         else
1535                 argv_array_push(&cp.args, "--index");
1536
1537         argv_array_push(&cp.args, am_path(state, "patch"));
1538
1539         if (run_command(&cp))
1540                 return -1;
1541
1542         /* Reload index as git-apply will have modified it. */
1543         discard_cache();
1544         read_cache_from(index_file ? index_file : get_index_file());
1545
1546         return 0;
1547 }
1548
1549 /**
1550  * Builds an index that contains just the blobs needed for a 3way merge.
1551  */
1552 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1553 {
1554         struct child_process cp = CHILD_PROCESS_INIT;
1555
1556         cp.git_cmd = 1;
1557         argv_array_push(&cp.args, "apply");
1558         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1559         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1560         argv_array_push(&cp.args, am_path(state, "patch"));
1561
1562         if (run_command(&cp))
1563                 return -1;
1564
1565         return 0;
1566 }
1567
1568 /**
1569  * Attempt a threeway merge, using index_path as the temporary index.
1570  */
1571 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1572 {
1573         struct object_id orig_tree, their_tree, our_tree;
1574         const struct object_id *bases[1] = { &orig_tree };
1575         struct merge_options o;
1576         struct commit *result;
1577         char *their_tree_name;
1578
1579         if (get_oid("HEAD", &our_tree) < 0)
1580                 hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
1581
1582         if (build_fake_ancestor(state, index_path))
1583                 return error("could not build fake ancestor");
1584
1585         discard_cache();
1586         read_cache_from(index_path);
1587
1588         if (write_index_as_tree(orig_tree.hash, &the_index, index_path, 0, NULL))
1589                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1590
1591         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1592
1593         if (!state->quiet) {
1594                 /*
1595                  * List paths that needed 3-way fallback, so that the user can
1596                  * review them with extra care to spot mismerges.
1597                  */
1598                 struct rev_info rev_info;
1599                 const char *diff_filter_str = "--diff-filter=AM";
1600
1601                 init_revisions(&rev_info, NULL);
1602                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1603                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1604                 add_pending_sha1(&rev_info, "HEAD", our_tree.hash, 0);
1605                 diff_setup_done(&rev_info.diffopt);
1606                 run_diff_index(&rev_info, 1);
1607         }
1608
1609         if (run_apply(state, index_path))
1610                 return error(_("Did you hand edit your patch?\n"
1611                                 "It does not apply to blobs recorded in its index."));
1612
1613         if (write_index_as_tree(their_tree.hash, &the_index, index_path, 0, NULL))
1614                 return error("could not write tree");
1615
1616         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1617
1618         discard_cache();
1619         read_cache();
1620
1621         /*
1622          * This is not so wrong. Depending on which base we picked, orig_tree
1623          * may be wildly different from ours, but their_tree has the same set of
1624          * wildly different changes in parts the patch did not touch, so
1625          * recursive ends up canceling them, saying that we reverted all those
1626          * changes.
1627          */
1628
1629         init_merge_options(&o);
1630
1631         o.branch1 = "HEAD";
1632         their_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
1633         o.branch2 = their_tree_name;
1634
1635         if (state->quiet)
1636                 o.verbosity = 0;
1637
1638         if (merge_recursive_generic(&o, &our_tree, &their_tree, 1, bases, &result)) {
1639                 rerere(state->allow_rerere_autoupdate);
1640                 free(their_tree_name);
1641                 return error(_("Failed to merge in the changes."));
1642         }
1643
1644         free(their_tree_name);
1645         return 0;
1646 }
1647
1648 /**
1649  * Commits the current index with state->msg as the commit message and
1650  * state->author_name, state->author_email and state->author_date as the author
1651  * information.
1652  */
1653 static void do_commit(const struct am_state *state)
1654 {
1655         unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
1656                       commit[GIT_SHA1_RAWSZ];
1657         unsigned char *ptr;
1658         struct commit_list *parents = NULL;
1659         const char *reflog_msg, *author;
1660         struct strbuf sb = STRBUF_INIT;
1661
1662         if (run_hook_le(NULL, "pre-applypatch", NULL))
1663                 exit(1);
1664
1665         if (write_cache_as_tree(tree, 0, NULL))
1666                 die(_("git write-tree failed to write a tree"));
1667
1668         if (!get_sha1_commit("HEAD", parent)) {
1669                 ptr = parent;
1670                 commit_list_insert(lookup_commit(parent), &parents);
1671         } else {
1672                 ptr = NULL;
1673                 say(state, stderr, _("applying to an empty history"));
1674         }
1675
1676         author = fmt_ident(state->author_name, state->author_email,
1677                         state->ignore_date ? NULL : state->author_date,
1678                         IDENT_STRICT);
1679
1680         if (state->committer_date_is_author_date)
1681                 setenv("GIT_COMMITTER_DATE",
1682                         state->ignore_date ? "" : state->author_date, 1);
1683
1684         if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
1685                                 author, state->sign_commit))
1686                 die(_("failed to write commit object"));
1687
1688         reflog_msg = getenv("GIT_REFLOG_ACTION");
1689         if (!reflog_msg)
1690                 reflog_msg = "am";
1691
1692         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1693                         state->msg);
1694
1695         update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
1696
1697         if (state->rebasing) {
1698                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1699
1700                 assert(!is_null_sha1(state->orig_commit));
1701                 fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
1702                 fprintf(fp, "%s\n", sha1_to_hex(commit));
1703                 fclose(fp);
1704         }
1705
1706         run_hook_le(NULL, "post-applypatch", NULL);
1707
1708         strbuf_release(&sb);
1709 }
1710
1711 /**
1712  * Validates the am_state for resuming -- the "msg" and authorship fields must
1713  * be filled up.
1714  */
1715 static void validate_resume_state(const struct am_state *state)
1716 {
1717         if (!state->msg)
1718                 die(_("cannot resume: %s does not exist."),
1719                         am_path(state, "final-commit"));
1720
1721         if (!state->author_name || !state->author_email || !state->author_date)
1722                 die(_("cannot resume: %s does not exist."),
1723                         am_path(state, "author-script"));
1724 }
1725
1726 /**
1727  * Interactively prompt the user on whether the current patch should be
1728  * applied.
1729  *
1730  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1731  * skip it.
1732  */
1733 static int do_interactive(struct am_state *state)
1734 {
1735         assert(state->msg);
1736
1737         if (!isatty(0))
1738                 die(_("cannot be interactive without stdin connected to a terminal."));
1739
1740         for (;;) {
1741                 const char *reply;
1742
1743                 puts(_("Commit Body is:"));
1744                 puts("--------------------------");
1745                 printf("%s", state->msg);
1746                 puts("--------------------------");
1747
1748                 /*
1749                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1750                  * in your translation. The program will only accept English
1751                  * input at this point.
1752                  */
1753                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1754
1755                 if (!reply) {
1756                         continue;
1757                 } else if (*reply == 'y' || *reply == 'Y') {
1758                         return 0;
1759                 } else if (*reply == 'a' || *reply == 'A') {
1760                         state->interactive = 0;
1761                         return 0;
1762                 } else if (*reply == 'n' || *reply == 'N') {
1763                         return 1;
1764                 } else if (*reply == 'e' || *reply == 'E') {
1765                         struct strbuf msg = STRBUF_INIT;
1766
1767                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1768                                 free(state->msg);
1769                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1770                         }
1771                         strbuf_release(&msg);
1772                 } else if (*reply == 'v' || *reply == 'V') {
1773                         const char *pager = git_pager(1);
1774                         struct child_process cp = CHILD_PROCESS_INIT;
1775
1776                         if (!pager)
1777                                 pager = "cat";
1778                         prepare_pager_args(&cp, pager);
1779                         argv_array_push(&cp.args, am_path(state, "patch"));
1780                         run_command(&cp);
1781                 }
1782         }
1783 }
1784
1785 /**
1786  * Applies all queued mail.
1787  *
1788  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1789  * well as the state directory's "patch" file is used as-is for applying the
1790  * patch and committing it.
1791  */
1792 static void am_run(struct am_state *state, int resume)
1793 {
1794         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1795         struct strbuf sb = STRBUF_INIT;
1796
1797         unlink(am_path(state, "dirtyindex"));
1798
1799         refresh_and_write_cache();
1800
1801         if (index_has_changes(&sb)) {
1802                 write_state_bool(state, "dirtyindex", 1);
1803                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1804         }
1805
1806         strbuf_release(&sb);
1807
1808         while (state->cur <= state->last) {
1809                 const char *mail = am_path(state, msgnum(state));
1810                 int apply_status;
1811
1812                 reset_ident_date();
1813
1814                 if (!file_exists(mail))
1815                         goto next;
1816
1817                 if (resume) {
1818                         validate_resume_state(state);
1819                 } else {
1820                         int skip;
1821
1822                         if (state->rebasing)
1823                                 skip = parse_mail_rebase(state, mail);
1824                         else
1825                                 skip = parse_mail(state, mail);
1826
1827                         if (skip)
1828                                 goto next; /* mail should be skipped */
1829
1830                         write_author_script(state);
1831                         write_commit_msg(state);
1832                 }
1833
1834                 if (state->interactive && do_interactive(state))
1835                         goto next;
1836
1837                 if (run_applypatch_msg_hook(state))
1838                         exit(1);
1839
1840                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1841
1842                 apply_status = run_apply(state, NULL);
1843
1844                 if (apply_status && state->threeway) {
1845                         struct strbuf sb = STRBUF_INIT;
1846
1847                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1848                         apply_status = fall_back_threeway(state, sb.buf);
1849                         strbuf_release(&sb);
1850
1851                         /*
1852                          * Applying the patch to an earlier tree and merging
1853                          * the result may have produced the same tree as ours.
1854                          */
1855                         if (!apply_status && !index_has_changes(NULL)) {
1856                                 say(state, stdout, _("No changes -- Patch already applied."));
1857                                 goto next;
1858                         }
1859                 }
1860
1861                 if (apply_status) {
1862                         int advice_amworkdir = 1;
1863
1864                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1865                                 linelen(state->msg), state->msg);
1866
1867                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1868
1869                         if (advice_amworkdir)
1870                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1871                                                 am_path(state, "patch"));
1872
1873                         die_user_resolve(state);
1874                 }
1875
1876                 do_commit(state);
1877
1878 next:
1879                 am_next(state);
1880
1881                 if (resume)
1882                         am_load(state);
1883                 resume = 0;
1884         }
1885
1886         if (!is_empty_file(am_path(state, "rewritten"))) {
1887                 assert(state->rebasing);
1888                 copy_notes_for_rebase(state);
1889                 run_post_rewrite_hook(state);
1890         }
1891
1892         /*
1893          * In rebasing mode, it's up to the caller to take care of
1894          * housekeeping.
1895          */
1896         if (!state->rebasing) {
1897                 am_destroy(state);
1898                 close_all_packs();
1899                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1900         }
1901 }
1902
1903 /**
1904  * Resume the current am session after patch application failure. The user did
1905  * all the hard work, and we do not have to do any patch application. Just
1906  * trust and commit what the user has in the index and working tree.
1907  */
1908 static void am_resolve(struct am_state *state)
1909 {
1910         validate_resume_state(state);
1911
1912         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1913
1914         if (!index_has_changes(NULL)) {
1915                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1916                         "If there is nothing left to stage, chances are that something else\n"
1917                         "already introduced the same changes; you might want to skip this patch."));
1918                 die_user_resolve(state);
1919         }
1920
1921         if (unmerged_cache()) {
1922                 printf_ln(_("You still have unmerged paths in your index.\n"
1923                         "Did you forget to use 'git add'?"));
1924                 die_user_resolve(state);
1925         }
1926
1927         if (state->interactive) {
1928                 write_index_patch(state);
1929                 if (do_interactive(state))
1930                         goto next;
1931         }
1932
1933         rerere(0);
1934
1935         do_commit(state);
1936
1937 next:
1938         am_next(state);
1939         am_load(state);
1940         am_run(state, 0);
1941 }
1942
1943 /**
1944  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1945  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1946  * failure.
1947  */
1948 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1949 {
1950         struct lock_file *lock_file;
1951         struct unpack_trees_options opts;
1952         struct tree_desc t[2];
1953
1954         if (parse_tree(head) || parse_tree(remote))
1955                 return -1;
1956
1957         lock_file = xcalloc(1, sizeof(struct lock_file));
1958         hold_locked_index(lock_file, 1);
1959
1960         refresh_cache(REFRESH_QUIET);
1961
1962         memset(&opts, 0, sizeof(opts));
1963         opts.head_idx = 1;
1964         opts.src_index = &the_index;
1965         opts.dst_index = &the_index;
1966         opts.update = 1;
1967         opts.merge = 1;
1968         opts.reset = reset;
1969         opts.fn = twoway_merge;
1970         init_tree_desc(&t[0], head->buffer, head->size);
1971         init_tree_desc(&t[1], remote->buffer, remote->size);
1972
1973         if (unpack_trees(2, t, &opts)) {
1974                 rollback_lock_file(lock_file);
1975                 return -1;
1976         }
1977
1978         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1979                 die(_("unable to write new index file"));
1980
1981         return 0;
1982 }
1983
1984 /**
1985  * Merges a tree into the index. The index's stat info will take precedence
1986  * over the merged tree's. Returns 0 on success, -1 on failure.
1987  */
1988 static int merge_tree(struct tree *tree)
1989 {
1990         struct lock_file *lock_file;
1991         struct unpack_trees_options opts;
1992         struct tree_desc t[1];
1993
1994         if (parse_tree(tree))
1995                 return -1;
1996
1997         lock_file = xcalloc(1, sizeof(struct lock_file));
1998         hold_locked_index(lock_file, 1);
1999
2000         memset(&opts, 0, sizeof(opts));
2001         opts.head_idx = 1;
2002         opts.src_index = &the_index;
2003         opts.dst_index = &the_index;
2004         opts.merge = 1;
2005         opts.fn = oneway_merge;
2006         init_tree_desc(&t[0], tree->buffer, tree->size);
2007
2008         if (unpack_trees(1, t, &opts)) {
2009                 rollback_lock_file(lock_file);
2010                 return -1;
2011         }
2012
2013         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2014                 die(_("unable to write new index file"));
2015
2016         return 0;
2017 }
2018
2019 /**
2020  * Clean the index without touching entries that are not modified between
2021  * `head` and `remote`.
2022  */
2023 static int clean_index(const unsigned char *head, const unsigned char *remote)
2024 {
2025         struct tree *head_tree, *remote_tree, *index_tree;
2026         unsigned char index[GIT_SHA1_RAWSZ];
2027
2028         head_tree = parse_tree_indirect(head);
2029         if (!head_tree)
2030                 return error(_("Could not parse object '%s'."), sha1_to_hex(head));
2031
2032         remote_tree = parse_tree_indirect(remote);
2033         if (!remote_tree)
2034                 return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
2035
2036         read_cache_unmerged();
2037
2038         if (fast_forward_to(head_tree, head_tree, 1))
2039                 return -1;
2040
2041         if (write_cache_as_tree(index, 0, NULL))
2042                 return -1;
2043
2044         index_tree = parse_tree_indirect(index);
2045         if (!index_tree)
2046                 return error(_("Could not parse object '%s'."), sha1_to_hex(index));
2047
2048         if (fast_forward_to(index_tree, remote_tree, 0))
2049                 return -1;
2050
2051         if (merge_tree(remote_tree))
2052                 return -1;
2053
2054         remove_branch_state();
2055
2056         return 0;
2057 }
2058
2059 /**
2060  * Resets rerere's merge resolution metadata.
2061  */
2062 static void am_rerere_clear(void)
2063 {
2064         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2065         rerere_clear(&merge_rr);
2066         string_list_clear(&merge_rr, 1);
2067 }
2068
2069 /**
2070  * Resume the current am session by skipping the current patch.
2071  */
2072 static void am_skip(struct am_state *state)
2073 {
2074         unsigned char head[GIT_SHA1_RAWSZ];
2075
2076         am_rerere_clear();
2077
2078         if (get_sha1("HEAD", head))
2079                 hashcpy(head, EMPTY_TREE_SHA1_BIN);
2080
2081         if (clean_index(head, head))
2082                 die(_("failed to clean index"));
2083
2084         am_next(state);
2085         am_load(state);
2086         am_run(state, 0);
2087 }
2088
2089 /**
2090  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2091  *
2092  * It is not safe to reset HEAD when:
2093  * 1. git-am previously failed because the index was dirty.
2094  * 2. HEAD has moved since git-am previously failed.
2095  */
2096 static int safe_to_abort(const struct am_state *state)
2097 {
2098         struct strbuf sb = STRBUF_INIT;
2099         unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
2100
2101         if (file_exists(am_path(state, "dirtyindex")))
2102                 return 0;
2103
2104         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2105                 if (get_sha1_hex(sb.buf, abort_safety))
2106                         die(_("could not parse %s"), am_path(state, "abort_safety"));
2107         } else
2108                 hashclr(abort_safety);
2109
2110         if (get_sha1("HEAD", head))
2111                 hashclr(head);
2112
2113         if (!hashcmp(head, abort_safety))
2114                 return 1;
2115
2116         error(_("You seem to have moved HEAD since the last 'am' failure.\n"
2117                 "Not rewinding to ORIG_HEAD"));
2118
2119         return 0;
2120 }
2121
2122 /**
2123  * Aborts the current am session if it is safe to do so.
2124  */
2125 static void am_abort(struct am_state *state)
2126 {
2127         unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
2128         int has_curr_head, has_orig_head;
2129         char *curr_branch;
2130
2131         if (!safe_to_abort(state)) {
2132                 am_destroy(state);
2133                 return;
2134         }
2135
2136         am_rerere_clear();
2137
2138         curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
2139         has_curr_head = !is_null_sha1(curr_head);
2140         if (!has_curr_head)
2141                 hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
2142
2143         has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
2144         if (!has_orig_head)
2145                 hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
2146
2147         clean_index(curr_head, orig_head);
2148
2149         if (has_orig_head)
2150                 update_ref("am --abort", "HEAD", orig_head,
2151                                 has_curr_head ? curr_head : NULL, 0,
2152                                 UPDATE_REFS_DIE_ON_ERR);
2153         else if (curr_branch)
2154                 delete_ref(curr_branch, NULL, REF_NODEREF);
2155
2156         free(curr_branch);
2157         am_destroy(state);
2158 }
2159
2160 /**
2161  * parse_options() callback that validates and sets opt->value to the
2162  * PATCH_FORMAT_* enum value corresponding to `arg`.
2163  */
2164 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2165 {
2166         int *opt_value = opt->value;
2167
2168         if (!strcmp(arg, "mbox"))
2169                 *opt_value = PATCH_FORMAT_MBOX;
2170         else if (!strcmp(arg, "stgit"))
2171                 *opt_value = PATCH_FORMAT_STGIT;
2172         else if (!strcmp(arg, "stgit-series"))
2173                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2174         else if (!strcmp(arg, "hg"))
2175                 *opt_value = PATCH_FORMAT_HG;
2176         else if (!strcmp(arg, "mboxrd"))
2177                 *opt_value = PATCH_FORMAT_MBOXRD;
2178         else
2179                 return error(_("Invalid value for --patch-format: %s"), arg);
2180         return 0;
2181 }
2182
2183 enum resume_mode {
2184         RESUME_FALSE = 0,
2185         RESUME_APPLY,
2186         RESUME_RESOLVED,
2187         RESUME_SKIP,
2188         RESUME_ABORT
2189 };
2190
2191 static int git_am_config(const char *k, const char *v, void *cb)
2192 {
2193         int status;
2194
2195         status = git_gpg_config(k, v, NULL);
2196         if (status)
2197                 return status;
2198
2199         return git_default_config(k, v, NULL);
2200 }
2201
2202 int cmd_am(int argc, const char **argv, const char *prefix)
2203 {
2204         struct am_state state;
2205         int binary = -1;
2206         int keep_cr = -1;
2207         int patch_format = PATCH_FORMAT_UNKNOWN;
2208         enum resume_mode resume = RESUME_FALSE;
2209         int in_progress;
2210
2211         const char * const usage[] = {
2212                 N_("git am [<options>] [(<mbox> | <Maildir>)...]"),
2213                 N_("git am [<options>] (--continue | --skip | --abort)"),
2214                 NULL
2215         };
2216
2217         struct option options[] = {
2218                 OPT_BOOL('i', "interactive", &state.interactive,
2219                         N_("run interactively")),
2220                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2221                         N_("historical option -- no-op")),
2222                 OPT_BOOL('3', "3way", &state.threeway,
2223                         N_("allow fall back on 3way merging if needed")),
2224                 OPT__QUIET(&state.quiet, N_("be quiet")),
2225                 OPT_SET_INT('s', "signoff", &state.signoff,
2226                         N_("add a Signed-off-by line to the commit message"),
2227                         SIGNOFF_EXPLICIT),
2228                 OPT_BOOL('u', "utf8", &state.utf8,
2229                         N_("recode into utf8 (default)")),
2230                 OPT_SET_INT('k', "keep", &state.keep,
2231                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2232                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2233                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2234                 OPT_BOOL('m', "message-id", &state.message_id,
2235                         N_("pass -m flag to git-mailinfo")),
2236                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2237                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2238                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2239                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2240                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2241                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2242                 OPT_BOOL('c', "scissors", &state.scissors,
2243                         N_("strip everything before a scissors line")),
2244                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2245                         N_("pass it through git-apply"),
2246                         0),
2247                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2248                         N_("pass it through git-apply"),
2249                         PARSE_OPT_NOARG),
2250                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2251                         N_("pass it through git-apply"),
2252                         PARSE_OPT_NOARG),
2253                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2254                         N_("pass it through git-apply"),
2255                         0),
2256                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2257                         N_("pass it through git-apply"),
2258                         0),
2259                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2260                         N_("pass it through git-apply"),
2261                         0),
2262                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2263                         N_("pass it through git-apply"),
2264                         0),
2265                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2266                         N_("pass it through git-apply"),
2267                         0),
2268                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2269                         N_("format the patch(es) are in"),
2270                         parse_opt_patchformat),
2271                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2272                         N_("pass it through git-apply"),
2273                         PARSE_OPT_NOARG),
2274                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2275                         N_("override error message when patch failure occurs")),
2276                 OPT_CMDMODE(0, "continue", &resume,
2277                         N_("continue applying patches after resolving a conflict"),
2278                         RESUME_RESOLVED),
2279                 OPT_CMDMODE('r', "resolved", &resume,
2280                         N_("synonyms for --continue"),
2281                         RESUME_RESOLVED),
2282                 OPT_CMDMODE(0, "skip", &resume,
2283                         N_("skip the current patch"),
2284                         RESUME_SKIP),
2285                 OPT_CMDMODE(0, "abort", &resume,
2286                         N_("restore the original branch and abort the patching operation."),
2287                         RESUME_ABORT),
2288                 OPT_BOOL(0, "committer-date-is-author-date",
2289                         &state.committer_date_is_author_date,
2290                         N_("lie about committer date")),
2291                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2292                         N_("use current timestamp for author date")),
2293                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2294                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2295                   N_("GPG-sign commits"),
2296                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2297                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2298                         N_("(internal use for git-rebase)")),
2299                 OPT_END()
2300         };
2301
2302         git_config(git_am_config, NULL);
2303
2304         am_state_init(&state, git_path("rebase-apply"));
2305
2306         in_progress = am_in_progress(&state);
2307         if (in_progress)
2308                 am_load(&state);
2309
2310         argc = parse_options(argc, argv, prefix, options, usage, 0);
2311
2312         if (binary >= 0)
2313                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2314                                 "it will be removed. Please do not use it anymore."));
2315
2316         /* Ensure a valid committer ident can be constructed */
2317         git_committer_info(IDENT_STRICT);
2318
2319         if (read_index_preload(&the_index, NULL) < 0)
2320                 die(_("failed to read the index"));
2321
2322         if (in_progress) {
2323                 /*
2324                  * Catch user error to feed us patches when there is a session
2325                  * in progress:
2326                  *
2327                  * 1. mbox path(s) are provided on the command-line.
2328                  * 2. stdin is not a tty: the user is trying to feed us a patch
2329                  *    from standard input. This is somewhat unreliable -- stdin
2330                  *    could be /dev/null for example and the caller did not
2331                  *    intend to feed us a patch but wanted to continue
2332                  *    unattended.
2333                  */
2334                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2335                         die(_("previous rebase directory %s still exists but mbox given."),
2336                                 state.dir);
2337
2338                 if (resume == RESUME_FALSE)
2339                         resume = RESUME_APPLY;
2340
2341                 if (state.signoff == SIGNOFF_EXPLICIT)
2342                         am_append_signoff(&state);
2343         } else {
2344                 struct argv_array paths = ARGV_ARRAY_INIT;
2345                 int i;
2346
2347                 /*
2348                  * Handle stray state directory in the independent-run case. In
2349                  * the --rebasing case, it is up to the caller to take care of
2350                  * stray directories.
2351                  */
2352                 if (file_exists(state.dir) && !state.rebasing) {
2353                         if (resume == RESUME_ABORT) {
2354                                 am_destroy(&state);
2355                                 am_state_release(&state);
2356                                 return 0;
2357                         }
2358
2359                         die(_("Stray %s directory found.\n"
2360                                 "Use \"git am --abort\" to remove it."),
2361                                 state.dir);
2362                 }
2363
2364                 if (resume)
2365                         die(_("Resolve operation not in progress, we are not resuming."));
2366
2367                 for (i = 0; i < argc; i++) {
2368                         if (is_absolute_path(argv[i]) || !prefix)
2369                                 argv_array_push(&paths, argv[i]);
2370                         else
2371                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2372                 }
2373
2374                 am_setup(&state, patch_format, paths.argv, keep_cr);
2375
2376                 argv_array_clear(&paths);
2377         }
2378
2379         switch (resume) {
2380         case RESUME_FALSE:
2381                 am_run(&state, 0);
2382                 break;
2383         case RESUME_APPLY:
2384                 am_run(&state, 1);
2385                 break;
2386         case RESUME_RESOLVED:
2387                 am_resolve(&state);
2388                 break;
2389         case RESUME_SKIP:
2390                 am_skip(&state);
2391                 break;
2392         case RESUME_ABORT:
2393                 am_abort(&state);
2394                 break;
2395         default:
2396                 die("BUG: invalid resume value");
2397         }
2398
2399         am_state_release(&state);
2400
2401         return 0;
2402 }