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