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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 "apply.h"
  32 #include "string-list.h"
  33
  34 /**
  35  * Returns 1 if the file is empty or does not exist, 0 otherwise.
  36  */
  37 static int is_empty_file(const char *filename)
  38 {
  39         struct stat st;
  40
  41         if (stat(filename, &st) < 0) {
  42                 if (errno == ENOENT)
  43                         return 1;
  44                 die_errno(_("could not stat %s"), filename);
  45         }
  46
  47         return !st.st_size;
  48 }
  49
  50 /**
  51  * Returns the length of the first line of msg.
  52  */
  53 static int linelen(const char *msg)
  54 {
  55         return strchrnul(msg, '\n') - msg;
  56 }
  57
  58 /**
  59  * Returns true if `str` consists of only whitespace, false otherwise.
  60  */
  61 static int str_isspace(const char *str)
  62 {
  63         for (; *str; str++)
  64                 if (!isspace(*str))
  65                         return 0;
  66
  67         return 1;
  68 }
  69
  70 enum patch_format {
  71         PATCH_FORMAT_UNKNOWN = 0,
  72         PATCH_FORMAT_MBOX,
  73         PATCH_FORMAT_STGIT,
  74         PATCH_FORMAT_STGIT_SERIES,
  75         PATCH_FORMAT_HG,
  76         PATCH_FORMAT_MBOXRD
  77 };
  78
  79 enum keep_type {
  80         KEEP_FALSE = 0,
  81         KEEP_TRUE,      /* pass -k flag to git-mailinfo */
  82         KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
  83 };
  84
  85 enum scissors_type {
  86         SCISSORS_UNSET = -1,
  87         SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
  88         SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
  89 };
  90
  91 enum signoff_type {
  92         SIGNOFF_FALSE = 0,
  93         SIGNOFF_TRUE = 1,
  94         SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
  95 };
  96
  97 struct am_state {
  98         /* state directory path */
  99         char *dir;
 100
 101         /* current and last patch numbers, 1-indexed */
 102         int cur;
 103         int last;
 104
 105         /* commit metadata and message */
 106         char *author_name;
 107         char *author_email;
 108         char *author_date;
 109         char *msg;
 110         size_t msg_len;
 111
 112         /* when --rebasing, records the original commit the patch came from */
 113         struct object_id orig_commit;
 114
 115         /* number of digits in patch filename */
 116         int prec;
 117
 118         /* various operating modes and command line options */
 119         int interactive;
 120         int threeway;
 121         int quiet;
 122         int signoff; /* enum signoff_type */
 123         int utf8;
 124         int keep; /* enum keep_type */
 125         int message_id;
 126         int scissors; /* enum scissors_type */
 127         struct argv_array git_apply_opts;
 128         const char *resolvemsg;
 129         int committer_date_is_author_date;
 130         int ignore_date;
 131         int allow_rerere_autoupdate;
 132         const char *sign_commit;
 133         int rebasing;
 134 };
 135
 136 /**
 137  * Initializes am_state with the default values.
 138  */
 139 static void am_state_init(struct am_state *state)
 140 {
 141         int gpgsign;
 142
 143         memset(state, 0, sizeof(*state));
 144
 145         state->dir = git_pathdup("rebase-apply");
 146
 147         state->prec = 4;
 148
 149         git_config_get_bool("am.threeway", &state->threeway);
 150
 151         state->utf8 = 1;
 152
 153         git_config_get_bool("am.messageid", &state->message_id);
 154
 155         state->scissors = SCISSORS_UNSET;
 156
 157         argv_array_init(&state->git_apply_opts);
 158
 159         if (!git_config_get_bool("commit.gpgsign", &gpgsign))
 160                 state->sign_commit = gpgsign ? "" : NULL;
 161 }
 162
 163 /**
 164  * Releases memory allocated by an am_state.
 165  */
 166 static void am_state_release(struct am_state *state)
 167 {
 168         free(state->dir);
 169         free(state->author_name);
 170         free(state->author_email);
 171         free(state->author_date);
 172         free(state->msg);
 173         argv_array_clear(&state->git_apply_opts);
 174 }
 175
 176 /**
 177  * Returns path relative to the am_state directory.
 178  */
 179 static inline const char *am_path(const struct am_state *state, const char *path)
 180 {
 181         return mkpath("%s/%s", state->dir, path);
 182 }
 183
 184 /**
 185  * For convenience to call write_file()
 186  */
 187 static void write_state_text(const struct am_state *state,
 188                              const char *name, const char *string)
 189 {
 190         write_file(am_path(state, name), "%s", string);
 191 }
 192
 193 static void write_state_count(const struct am_state *state,
 194                               const char *name, int value)
 195 {
 196         write_file(am_path(state, name), "%d", value);
 197 }
 198
 199 static void write_state_bool(const struct am_state *state,
 200                              const char *name, int value)
 201 {
 202         write_state_text(state, name, value ? "t" : "f");
 203 }
 204
 205 /**
 206  * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
 207  * at the end.
 208  */
 209 static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
 210 {
 211         va_list ap;
 212
 213         va_start(ap, fmt);
 214         if (!state->quiet) {
 215                 vfprintf(fp, fmt, ap);
 216                 putc('\n', fp);
 217         }
 218         va_end(ap);
 219 }
 220
 221 /**
 222  * Returns 1 if there is an am session in progress, 0 otherwise.
 223  */
 224 static int am_in_progress(const struct am_state *state)
 225 {
 226         struct stat st;
 227
 228         if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
 229                 return 0;
 230         if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
 231                 return 0;
 232         if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
 233                 return 0;
 234         return 1;
 235 }
 236
 237 /**
 238  * Reads the contents of `file` in the `state` directory into `sb`. Returns the
 239  * number of bytes read on success, -1 if the file does not exist. If `trim` is
 240  * set, trailing whitespace will be removed.
 241  */
 242 static int read_state_file(struct strbuf *sb, const struct am_state *state,
 243                         const char *file, int trim)
 244 {
 245         strbuf_reset(sb);
 246
 247         if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
 248                 if (trim)
 249                         strbuf_trim(sb);
 250
 251                 return sb->len;
 252         }
 253
 254         if (errno == ENOENT)
 255                 return -1;
 256
 257         die_errno(_("could not read '%s'"), am_path(state, file));
 258 }
 259
 260 /**
 261  * Take a series of KEY='VALUE' lines where VALUE part is
 262  * sq-quoted, and append <KEY, VALUE> at the end of the string list
 263  */
 264 static int parse_key_value_squoted(char *buf, struct string_list *list)
 265 {
 266         while (*buf) {
 267                 struct string_list_item *item;
 268                 char *np;
 269                 char *cp = strchr(buf, '=');
 270                 if (!cp)
 271                         return -1;
 272                 np = strchrnul(cp, '\n');
 273                 *cp++ = '\0';
 274                 item = string_list_append(list, buf);
 275
 276                 buf = np + (*np == '\n');
 277                 *np = '\0';
 278                 cp = sq_dequote(cp);
 279                 if (!cp)
 280                         return -1;
 281                 item->util = xstrdup(cp);
 282         }
 283         return 0;
 284 }
 285
 286 /**
 287  * Reads and parses the state directory's "author-script" file, and sets
 288  * state->author_name, state->author_email and state->author_date accordingly.
 289  * Returns 0 on success, -1 if the file could not be parsed.
 290  *
 291  * The author script is of the format:
 292  *
 293  *      GIT_AUTHOR_NAME='$author_name'
 294  *      GIT_AUTHOR_EMAIL='$author_email'
 295  *      GIT_AUTHOR_DATE='$author_date'
 296  *
 297  * where $author_name, $author_email and $author_date are quoted. We are strict
 298  * with our parsing, as the file was meant to be eval'd in the old git-am.sh
 299  * script, and thus if the file differs from what this function expects, it is
 300  * better to bail out than to do something that the user does not expect.
 301  */
 302 static int read_author_script(struct am_state *state)
 303 {
 304         const char *filename = am_path(state, "author-script");
 305         struct strbuf buf = STRBUF_INIT;
 306         struct string_list kv = STRING_LIST_INIT_DUP;
 307         int retval = -1; /* assume failure */
 308         int fd;
 309
 310         assert(!state->author_name);
 311         assert(!state->author_email);
 312         assert(!state->author_date);
 313
 314         fd = open(filename, O_RDONLY);
 315         if (fd < 0) {
 316                 if (errno == ENOENT)
 317                         return 0;
 318                 die_errno(_("could not open '%s' for reading"), filename);
 319         }
 320         strbuf_read(&buf, fd, 0);
 321         close(fd);
 322         if (parse_key_value_squoted(buf.buf, &kv))
 323                 goto finish;
 324
 325         if (kv.nr != 3 ||
 326             strcmp(kv.items[0].string, "GIT_AUTHOR_NAME") ||
 327             strcmp(kv.items[1].string, "GIT_AUTHOR_EMAIL") ||
 328             strcmp(kv.items[2].string, "GIT_AUTHOR_DATE"))
 329                 goto finish;
 330         state->author_name = kv.items[0].util;
 331         state->author_email = kv.items[1].util;
 332         state->author_date = kv.items[2].util;
 333         retval = 0;
 334 finish:
 335         string_list_clear(&kv, !!retval);
 336         strbuf_release(&buf);
 337         return retval;
 338 }
 339
 340 /**
 341  * Saves state->author_name, state->author_email and state->author_date in the
 342  * state directory's "author-script" file.
 343  */
 344 static void write_author_script(const struct am_state *state)
 345 {
 346         struct strbuf sb = STRBUF_INIT;
 347
 348         strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
 349         sq_quote_buf(&sb, state->author_name);
 350         strbuf_addch(&sb, '\n');
 351
 352         strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
 353         sq_quote_buf(&sb, state->author_email);
 354         strbuf_addch(&sb, '\n');
 355
 356         strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
 357         sq_quote_buf(&sb, state->author_date);
 358         strbuf_addch(&sb, '\n');
 359
 360         write_state_text(state, "author-script", sb.buf);
 361
 362         strbuf_release(&sb);
 363 }
 364
 365 /**
 366  * Reads the commit message from the state directory's "final-commit" file,
 367  * setting state->msg to its contents and state->msg_len to the length of its
 368  * contents in bytes.
 369  *
 370  * Returns 0 on success, -1 if the file does not exist.
 371  */
 372 static int read_commit_msg(struct am_state *state)
 373 {
 374         struct strbuf sb = STRBUF_INIT;
 375
 376         assert(!state->msg);
 377
 378         if (read_state_file(&sb, state, "final-commit", 0) < 0) {
 379                 strbuf_release(&sb);
 380                 return -1;
 381         }
 382
 383         state->msg = strbuf_detach(&sb, &state->msg_len);
 384         return 0;
 385 }
 386
 387 /**
 388  * Saves state->msg in the state directory's "final-commit" file.
 389  */
 390 static void write_commit_msg(const struct am_state *state)
 391 {
 392         const char *filename = am_path(state, "final-commit");
 393         write_file_buf(filename, state->msg, state->msg_len);
 394 }
 395
 396 /**
 397  * Loads state from disk.
 398  */
 399 static void am_load(struct am_state *state)
 400 {
 401         struct strbuf sb = STRBUF_INIT;
 402
 403         if (read_state_file(&sb, state, "next", 1) < 0)
 404                 die("BUG: state file 'next' does not exist");
 405         state->cur = strtol(sb.buf, NULL, 10);
 406
 407         if (read_state_file(&sb, state, "last", 1) < 0)
 408                 die("BUG: state file 'last' does not exist");
 409         state->last = strtol(sb.buf, NULL, 10);
 410
 411         if (read_author_script(state) < 0)
 412                 die(_("could not parse author script"));
 413
 414         read_commit_msg(state);
 415
 416         if (read_state_file(&sb, state, "original-commit", 1) < 0)
 417                 oidclr(&state->orig_commit);
 418         else if (get_oid_hex(sb.buf, &state->orig_commit) < 0)
 419                 die(_("could not parse %s"), am_path(state, "original-commit"));
 420
 421         read_state_file(&sb, state, "threeway", 1);
 422         state->threeway = !strcmp(sb.buf, "t");
 423
 424         read_state_file(&sb, state, "quiet", 1);
 425         state->quiet = !strcmp(sb.buf, "t");
 426
 427         read_state_file(&sb, state, "sign", 1);
 428         state->signoff = !strcmp(sb.buf, "t");
 429
 430         read_state_file(&sb, state, "utf8", 1);
 431         state->utf8 = !strcmp(sb.buf, "t");
 432
 433         read_state_file(&sb, state, "keep", 1);
 434         if (!strcmp(sb.buf, "t"))
 435                 state->keep = KEEP_TRUE;
 436         else if (!strcmp(sb.buf, "b"))
 437                 state->keep = KEEP_NON_PATCH;
 438         else
 439                 state->keep = KEEP_FALSE;
 440
 441         read_state_file(&sb, state, "messageid", 1);
 442         state->message_id = !strcmp(sb.buf, "t");
 443
 444         read_state_file(&sb, state, "scissors", 1);
 445         if (!strcmp(sb.buf, "t"))
 446                 state->scissors = SCISSORS_TRUE;
 447         else if (!strcmp(sb.buf, "f"))
 448                 state->scissors = SCISSORS_FALSE;
 449         else
 450                 state->scissors = SCISSORS_UNSET;
 451
 452         read_state_file(&sb, state, "apply-opt", 1);
 453         argv_array_clear(&state->git_apply_opts);
 454         if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
 455                 die(_("could not parse %s"), am_path(state, "apply-opt"));
 456
 457         state->rebasing = !!file_exists(am_path(state, "rebasing"));
 458
 459         strbuf_release(&sb);
 460 }
 461
 462 /**
 463  * Removes the am_state directory, forcefully terminating the current am
 464  * session.
 465  */
 466 static void am_destroy(const struct am_state *state)
 467 {
 468         struct strbuf sb = STRBUF_INIT;
 469
 470         strbuf_addstr(&sb, state->dir);
 471         remove_dir_recursively(&sb, 0);
 472         strbuf_release(&sb);
 473 }
 474
 475 /**
 476  * Runs applypatch-msg hook. Returns its exit code.
 477  */
 478 static int run_applypatch_msg_hook(struct am_state *state)
 479 {
 480         int ret;
 481
 482         assert(state->msg);
 483         ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
 484
 485         if (!ret) {
 486                 free(state->msg);
 487                 state->msg = NULL;
 488                 if (read_commit_msg(state) < 0)
 489                         die(_("'%s' was deleted by the applypatch-msg hook"),
 490                                 am_path(state, "final-commit"));
 491         }
 492
 493         return ret;
 494 }
 495
 496 /**
 497  * Runs post-rewrite hook. Returns it exit code.
 498  */
 499 static int run_post_rewrite_hook(const struct am_state *state)
 500 {
 501         struct child_process cp = CHILD_PROCESS_INIT;
 502         const char *hook = find_hook("post-rewrite");
 503         int ret;
 504
 505         if (!hook)
 506                 return 0;
 507
 508         argv_array_push(&cp.args, hook);
 509         argv_array_push(&cp.args, "rebase");
 510
 511         cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
 512         cp.stdout_to_stderr = 1;
 513
 514         ret = run_command(&cp);
 515
 516         close(cp.in);
 517         return ret;
 518 }
 519
 520 /**
 521  * Reads the state directory's "rewritten" file, and copies notes from the old
 522  * commits listed in the file to their rewritten commits.
 523  *
 524  * Returns 0 on success, -1 on failure.
 525  */
 526 static int copy_notes_for_rebase(const struct am_state *state)
 527 {
 528         struct notes_rewrite_cfg *c;
 529         struct strbuf sb = STRBUF_INIT;
 530         const char *invalid_line = _("Malformed input line: '%s'.");
 531         const char *msg = "Notes added by 'git rebase'";
 532         FILE *fp;
 533         int ret = 0;
 534
 535         assert(state->rebasing);
 536
 537         c = init_copy_notes_for_rewrite("rebase");
 538         if (!c)
 539                 return 0;
 540
 541         fp = xfopen(am_path(state, "rewritten"), "r");
 542
 543         while (!strbuf_getline_lf(&sb, fp)) {
 544                 struct object_id from_obj, to_obj;
 545
 546                 if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
 547                         ret = error(invalid_line, sb.buf);
 548                         goto finish;
 549                 }
 550
 551                 if (get_oid_hex(sb.buf, &from_obj)) {
 552                         ret = error(invalid_line, sb.buf);
 553                         goto finish;
 554                 }
 555
 556                 if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
 557                         ret = error(invalid_line, sb.buf);
 558                         goto finish;
 559                 }
 560
 561                 if (get_oid_hex(sb.buf + GIT_SHA1_HEXSZ + 1, &to_obj)) {
 562                         ret = error(invalid_line, sb.buf);
 563                         goto finish;
 564                 }
 565
 566                 if (copy_note_for_rewrite(c, from_obj.hash, to_obj.hash))
 567                         ret = error(_("Failed to copy notes from '%s' to '%s'"),
 568                                         oid_to_hex(&from_obj), oid_to_hex(&to_obj));
 569         }
 570
 571 finish:
 572         finish_copy_notes_for_rewrite(c, msg);
 573         fclose(fp);
 574         strbuf_release(&sb);
 575         return ret;
 576 }
 577
 578 /**
 579  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
 580  * non-indented lines and checking if they look like they begin with valid
 581  * header field names.
 582  *
 583  * Returns 1 if the file looks like a piece of mail, 0 otherwise.
 584  */
 585 static int is_mail(FILE *fp)
 586 {
 587         const char *header_regex = "^[!-9;-~]+:";
 588         struct strbuf sb = STRBUF_INIT;
 589         regex_t regex;
 590         int ret = 1;
 591
 592         if (fseek(fp, 0L, SEEK_SET))
 593                 die_errno(_("fseek failed"));
 594
 595         if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
 596                 die("invalid pattern: %s", header_regex);
 597
 598         while (!strbuf_getline(&sb, fp)) {
 599                 if (!sb.len)
 600                         break; /* End of header */
 601
 602                 /* Ignore indented folded lines */
 603                 if (*sb.buf == '\t' || *sb.buf == ' ')
 604                         continue;
 605
 606                 /* It's a header if it matches header_regex */
 607                 if (regexec(&regex, sb.buf, 0, NULL, 0)) {
 608                         ret = 0;
 609                         goto done;
 610                 }
 611         }
 612
 613 done:
 614         regfree(&regex);
 615         strbuf_release(&sb);
 616         return ret;
 617 }
 618
 619 /**
 620  * Attempts to detect the patch_format of the patches contained in `paths`,
 621  * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
 622  * detection fails.
 623  */
 624 static int detect_patch_format(const char **paths)
 625 {
 626         enum patch_format ret = PATCH_FORMAT_UNKNOWN;
 627         struct strbuf l1 = STRBUF_INIT;
 628         struct strbuf l2 = STRBUF_INIT;
 629         struct strbuf l3 = STRBUF_INIT;
 630         FILE *fp;
 631
 632         /*
 633          * We default to mbox format if input is from stdin and for directories
 634          */
 635         if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
 636                 return PATCH_FORMAT_MBOX;
 637
 638         /*
 639          * Otherwise, check the first few lines of the first patch, starting
 640          * from the first non-blank line, to try to detect its format.
 641          */
 642
 643         fp = xfopen(*paths, "r");
 644
 645         while (!strbuf_getline(&l1, fp)) {
 646                 if (l1.len)
 647                         break;
 648         }
 649
 650         if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
 651                 ret = PATCH_FORMAT_MBOX;
 652                 goto done;
 653         }
 654
 655         if (starts_with(l1.buf, "# This series applies on GIT commit")) {
 656                 ret = PATCH_FORMAT_STGIT_SERIES;
 657                 goto done;
 658         }
 659
 660         if (!strcmp(l1.buf, "# HG changeset patch")) {
 661                 ret = PATCH_FORMAT_HG;
 662                 goto done;
 663         }
 664
 665         strbuf_reset(&l2);
 666         strbuf_getline(&l2, fp);
 667         strbuf_reset(&l3);
 668         strbuf_getline(&l3, fp);
 669
 670         /*
 671          * If the second line is empty and the third is a From, Author or Date
 672          * entry, this is likely an StGit patch.
 673          */
 674         if (l1.len && !l2.len &&
 675                 (starts_with(l3.buf, "From:") ||
 676                  starts_with(l3.buf, "Author:") ||
 677                  starts_with(l3.buf, "Date:"))) {
 678                 ret = PATCH_FORMAT_STGIT;
 679                 goto done;
 680         }
 681
 682         if (l1.len && is_mail(fp)) {
 683                 ret = PATCH_FORMAT_MBOX;
 684                 goto done;
 685         }
 686
 687 done:
 688         fclose(fp);
 689         strbuf_release(&l1);
 690         return ret;
 691 }
 692
 693 /**
 694  * Splits out individual email patches from `paths`, where each path is either
 695  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
 696  */
 697 static int split_mail_mbox(struct am_state *state, const char **paths,
 698                                 int keep_cr, int mboxrd)
 699 {
 700         struct child_process cp = CHILD_PROCESS_INIT;
 701         struct strbuf last = STRBUF_INIT;
 702
 703         cp.git_cmd = 1;
 704         argv_array_push(&cp.args, "mailsplit");
 705         argv_array_pushf(&cp.args, "-d%d", state->prec);
 706         argv_array_pushf(&cp.args, "-o%s", state->dir);
 707         argv_array_push(&cp.args, "-b");
 708         if (keep_cr)
 709                 argv_array_push(&cp.args, "--keep-cr");
 710         if (mboxrd)
 711                 argv_array_push(&cp.args, "--mboxrd");
 712         argv_array_push(&cp.args, "--");
 713         argv_array_pushv(&cp.args, paths);
 714
 715         if (capture_command(&cp, &last, 8))
 716                 return -1;
 717
 718         state->cur = 1;
 719         state->last = strtol(last.buf, NULL, 10);
 720
 721         return 0;
 722 }
 723
 724 /**
 725  * Callback signature for split_mail_conv(). The foreign patch should be
 726  * read from `in`, and the converted patch (in RFC2822 mail format) should be
 727  * written to `out`. Return 0 on success, or -1 on failure.
 728  */
 729 typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
 730
 731 /**
 732  * Calls `fn` for each file in `paths` to convert the foreign patch to the
 733  * RFC2822 mail format suitable for parsing with git-mailinfo.
 734  *
 735  * Returns 0 on success, -1 on failure.
 736  */
 737 static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
 738                         const char **paths, int keep_cr)
 739 {
 740         static const char *stdin_only[] = {"-", NULL};
 741         int i;
 742
 743         if (!*paths)
 744                 paths = stdin_only;
 745
 746         for (i = 0; *paths; paths++, i++) {
 747                 FILE *in, *out;
 748                 const char *mail;
 749                 int ret;
 750
 751                 if (!strcmp(*paths, "-"))
 752                         in = stdin;
 753                 else
 754                         in = fopen(*paths, "r");
 755
 756                 if (!in)
 757                         return error_errno(_("could not open '%s' for reading"),
 758                                            *paths);
 759
 760                 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
 761
 762                 out = fopen(mail, "w");
 763                 if (!out) {
 764                         if (in != stdin)
 765                                 fclose(in);
 766                         return error_errno(_("could not open '%s' for writing"),
 767                                            mail);
 768                 }
 769
 770                 ret = fn(out, in, keep_cr);
 771
 772                 fclose(out);
 773                 if (in != stdin)
 774                         fclose(in);
 775
 776                 if (ret)
 777                         return error(_("could not parse patch '%s'"), *paths);
 778         }
 779
 780         state->cur = 1;
 781         state->last = i;
 782         return 0;
 783 }
 784
 785 /**
 786  * A split_mail_conv() callback that converts an StGit patch to an RFC2822
 787  * message suitable for parsing with git-mailinfo.
 788  */
 789 static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 790 {
 791         struct strbuf sb = STRBUF_INIT;
 792         int subject_printed = 0;
 793
 794         while (!strbuf_getline_lf(&sb, in)) {
 795                 const char *str;
 796
 797                 if (str_isspace(sb.buf))
 798                         continue;
 799                 else if (skip_prefix(sb.buf, "Author:", &str))
 800                         fprintf(out, "From:%s\n", str);
 801                 else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
 802                         fprintf(out, "%s\n", sb.buf);
 803                 else if (!subject_printed) {
 804                         fprintf(out, "Subject: %s\n", sb.buf);
 805                         subject_printed = 1;
 806                 } else {
 807                         fprintf(out, "\n%s\n", sb.buf);
 808                         break;
 809                 }
 810         }
 811
 812         strbuf_reset(&sb);
 813         while (strbuf_fread(&sb, 8192, in) > 0) {
 814                 fwrite(sb.buf, 1, sb.len, out);
 815                 strbuf_reset(&sb);
 816         }
 817
 818         strbuf_release(&sb);
 819         return 0;
 820 }
 821
 822 /**
 823  * This function only supports a single StGit series file in `paths`.
 824  *
 825  * Given an StGit series file, converts the StGit patches in the series into
 826  * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
 827  * the state directory.
 828  *
 829  * Returns 0 on success, -1 on failure.
 830  */
 831 static int split_mail_stgit_series(struct am_state *state, const char **paths,
 832                                         int keep_cr)
 833 {
 834         const char *series_dir;
 835         char *series_dir_buf;
 836         FILE *fp;
 837         struct argv_array patches = ARGV_ARRAY_INIT;
 838         struct strbuf sb = STRBUF_INIT;
 839         int ret;
 840
 841         if (!paths[0] || paths[1])
 842                 return error(_("Only one StGIT patch series can be applied at once"));
 843
 844         series_dir_buf = xstrdup(*paths);
 845         series_dir = dirname(series_dir_buf);
 846
 847         fp = fopen(*paths, "r");
 848         if (!fp)
 849                 return error_errno(_("could not open '%s' for reading"), *paths);
 850
 851         while (!strbuf_getline_lf(&sb, fp)) {
 852                 if (*sb.buf == '#')
 853                         continue; /* skip comment lines */
 854
 855                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
 856         }
 857
 858         fclose(fp);
 859         strbuf_release(&sb);
 860         free(series_dir_buf);
 861
 862         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
 863
 864         argv_array_clear(&patches);
 865         return ret;
 866 }
 867
 868 /**
 869  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
 870  * message suitable for parsing with git-mailinfo.
 871  */
 872 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
 873 {
 874         struct strbuf sb = STRBUF_INIT;
 875
 876         while (!strbuf_getline_lf(&sb, in)) {
 877                 const char *str;
 878
 879                 if (skip_prefix(sb.buf, "# User ", &str))
 880                         fprintf(out, "From: %s\n", str);
 881                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
 882                         timestamp_t timestamp;
 883                         long tz, tz2;
 884                         char *end;
 885
 886                         errno = 0;
 887                         timestamp = parse_timestamp(str, &end, 10);
 888                         if (errno)
 889                                 return error(_("invalid timestamp"));
 890
 891                         if (!skip_prefix(end, " ", &str))
 892                                 return error(_("invalid Date line"));
 893
 894                         errno = 0;
 895                         tz = strtol(str, &end, 10);
 896                         if (errno)
 897                                 return error(_("invalid timezone offset"));
 898
 899                         if (*end)
 900                                 return error(_("invalid Date line"));
 901
 902                         /*
 903                          * mercurial's timezone is in seconds west of UTC,
 904                          * however git's timezone is in hours + minutes east of
 905                          * UTC. Convert it.
 906                          */
 907                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
 908                         if (tz > 0)
 909                                 tz2 = -tz2;
 910
 911                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
 912                 } else if (starts_with(sb.buf, "# ")) {
 913                         continue;
 914                 } else {
 915                         fprintf(out, "\n%s\n", sb.buf);
 916                         break;
 917                 }
 918         }
 919
 920         strbuf_reset(&sb);
 921         while (strbuf_fread(&sb, 8192, in) > 0) {
 922                 fwrite(sb.buf, 1, sb.len, out);
 923                 strbuf_reset(&sb);
 924         }
 925
 926         strbuf_release(&sb);
 927         return 0;
 928 }
 929
 930 /**
 931  * Splits a list of files/directories into individual email patches. Each path
 932  * in `paths` must be a file/directory that is formatted according to
 933  * `patch_format`.
 934  *
 935  * Once split out, the individual email patches will be stored in the state
 936  * directory, with each patch's filename being its index, padded to state->prec
 937  * digits.
 938  *
 939  * state->cur will be set to the index of the first mail, and state->last will
 940  * be set to the index of the last mail.
 941  *
 942  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
 943  * to disable this behavior, -1 to use the default configured setting.
 944  *
 945  * Returns 0 on success, -1 on failure.
 946  */
 947 static int split_mail(struct am_state *state, enum patch_format patch_format,
 948                         const char **paths, int keep_cr)
 949 {
 950         if (keep_cr < 0) {
 951                 keep_cr = 0;
 952                 git_config_get_bool("am.keepcr", &keep_cr);
 953         }
 954
 955         switch (patch_format) {
 956         case PATCH_FORMAT_MBOX:
 957                 return split_mail_mbox(state, paths, keep_cr, 0);
 958         case PATCH_FORMAT_STGIT:
 959                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
 960         case PATCH_FORMAT_STGIT_SERIES:
 961                 return split_mail_stgit_series(state, paths, keep_cr);
 962         case PATCH_FORMAT_HG:
 963                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
 964         case PATCH_FORMAT_MBOXRD:
 965                 return split_mail_mbox(state, paths, keep_cr, 1);
 966         default:
 967                 die("BUG: invalid patch_format");
 968         }
 969         return -1;
 970 }
 971
 972 /**
 973  * Setup a new am session for applying patches
 974  */
 975 static void am_setup(struct am_state *state, enum patch_format patch_format,
 976                         const char **paths, int keep_cr)
 977 {
 978         struct object_id curr_head;
 979         const char *str;
 980         struct strbuf sb = STRBUF_INIT;
 981
 982         if (!patch_format)
 983                 patch_format = detect_patch_format(paths);
 984
 985         if (!patch_format) {
 986                 fprintf_ln(stderr, _("Patch format detection failed."));
 987                 exit(128);
 988         }
 989
 990         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
 991                 die_errno(_("failed to create directory '%s'"), state->dir);
 992
 993         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
 994                 am_destroy(state);
 995                 die(_("Failed to split patches."));
 996         }
 997
 998         if (state->rebasing)
 999                 state->threeway = 1;
1000
1001         write_state_bool(state, "threeway", state->threeway);
1002         write_state_bool(state, "quiet", state->quiet);
1003         write_state_bool(state, "sign", state->signoff);
1004         write_state_bool(state, "utf8", state->utf8);
1005
1006         switch (state->keep) {
1007         case KEEP_FALSE:
1008                 str = "f";
1009                 break;
1010         case KEEP_TRUE:
1011                 str = "t";
1012                 break;
1013         case KEEP_NON_PATCH:
1014                 str = "b";
1015                 break;
1016         default:
1017                 die("BUG: invalid value for state->keep");
1018         }
1019
1020         write_state_text(state, "keep", str);
1021         write_state_bool(state, "messageid", state->message_id);
1022
1023         switch (state->scissors) {
1024         case SCISSORS_UNSET:
1025                 str = "";
1026                 break;
1027         case SCISSORS_FALSE:
1028                 str = "f";
1029                 break;
1030         case SCISSORS_TRUE:
1031                 str = "t";
1032                 break;
1033         default:
1034                 die("BUG: invalid value for state->scissors");
1035         }
1036         write_state_text(state, "scissors", str);
1037
1038         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1039         write_state_text(state, "apply-opt", sb.buf);
1040
1041         if (state->rebasing)
1042                 write_state_text(state, "rebasing", "");
1043         else
1044                 write_state_text(state, "applying", "");
1045
1046         if (!get_oid("HEAD", &curr_head)) {
1047                 write_state_text(state, "abort-safety", oid_to_hex(&curr_head));
1048                 if (!state->rebasing)
1049                         update_ref_oid("am", "ORIG_HEAD", &curr_head, NULL, 0,
1050                                         UPDATE_REFS_DIE_ON_ERR);
1051         } else {
1052                 write_state_text(state, "abort-safety", "");
1053                 if (!state->rebasing)
1054                         delete_ref(NULL, "ORIG_HEAD", NULL, 0);
1055         }
1056
1057         /*
1058          * NOTE: Since the "next" and "last" files determine if an am_state
1059          * session is in progress, they should be written last.
1060          */
1061
1062         write_state_count(state, "next", state->cur);
1063         write_state_count(state, "last", state->last);
1064
1065         strbuf_release(&sb);
1066 }
1067
1068 /**
1069  * Increments the patch pointer, and cleans am_state for the application of the
1070  * next patch.
1071  */
1072 static void am_next(struct am_state *state)
1073 {
1074         struct object_id head;
1075
1076         free(state->author_name);
1077         state->author_name = NULL;
1078
1079         free(state->author_email);
1080         state->author_email = NULL;
1081
1082         free(state->author_date);
1083         state->author_date = NULL;
1084
1085         free(state->msg);
1086         state->msg = NULL;
1087         state->msg_len = 0;
1088
1089         unlink(am_path(state, "author-script"));
1090         unlink(am_path(state, "final-commit"));
1091
1092         oidclr(&state->orig_commit);
1093         unlink(am_path(state, "original-commit"));
1094
1095         if (!get_oid("HEAD", &head))
1096                 write_state_text(state, "abort-safety", oid_to_hex(&head));
1097         else
1098                 write_state_text(state, "abort-safety", "");
1099
1100         state->cur++;
1101         write_state_count(state, "next", state->cur);
1102 }
1103
1104 /**
1105  * Returns the filename of the current patch email.
1106  */
1107 static const char *msgnum(const struct am_state *state)
1108 {
1109         static struct strbuf sb = STRBUF_INIT;
1110
1111         strbuf_reset(&sb);
1112         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1113
1114         return sb.buf;
1115 }
1116
1117 /**
1118  * Refresh and write index.
1119  */
1120 static void refresh_and_write_cache(void)
1121 {
1122         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1123
1124         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1125         refresh_cache(REFRESH_QUIET);
1126         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1127                 die(_("unable to write index file"));
1128 }
1129
1130 /**
1131  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1132  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1133  * strbuf is provided, the space-separated list of files that differ will be
1134  * appended to it.
1135  */
1136 static int index_has_changes(struct strbuf *sb)
1137 {
1138         struct object_id head;
1139         int i;
1140
1141         if (!get_sha1_tree("HEAD", head.hash)) {
1142                 struct diff_options opt;
1143
1144                 diff_setup(&opt);
1145                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1146                 if (!sb)
1147                         DIFF_OPT_SET(&opt, QUICK);
1148                 do_diff_cache(&head, &opt);
1149                 diffcore_std(&opt);
1150                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1151                         if (i)
1152                                 strbuf_addch(sb, ' ');
1153                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1154                 }
1155                 diff_flush(&opt);
1156                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1157         } else {
1158                 for (i = 0; sb && i < active_nr; i++) {
1159                         if (i)
1160                                 strbuf_addch(sb, ' ');
1161                         strbuf_addstr(sb, active_cache[i]->name);
1162                 }
1163                 return !!active_nr;
1164         }
1165 }
1166
1167 /**
1168  * Dies with a user-friendly message on how to proceed after resolving the
1169  * problem. This message can be overridden with state->resolvemsg.
1170  */
1171 static void NORETURN die_user_resolve(const struct am_state *state)
1172 {
1173         if (state->resolvemsg) {
1174                 printf_ln("%s", state->resolvemsg);
1175         } else {
1176                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1177
1178                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1179                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1180                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1181         }
1182
1183         exit(128);
1184 }
1185
1186 /**
1187  * Appends signoff to the "msg" field of the am_state.
1188  */
1189 static void am_append_signoff(struct am_state *state)
1190 {
1191         char *cp;
1192         struct strbuf mine = STRBUF_INIT;
1193         struct strbuf sb = STRBUF_INIT;
1194
1195         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1196
1197         /* our sign-off */
1198         strbuf_addf(&mine, "\n%s%s\n",
1199                     sign_off_header,
1200                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1201                              getenv("GIT_COMMITTER_EMAIL")));
1202
1203         /* Does sb end with it already? */
1204         if (mine.len < sb.len &&
1205             !strcmp(mine.buf, sb.buf + sb.len - mine.len))
1206                 goto exit; /* no need to duplicate */
1207
1208         /* Does it have any Signed-off-by: in the text */
1209         for (cp = sb.buf;
1210              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1211              cp = strchr(cp, '\n')) {
1212                 if (sb.buf == cp || cp[-1] == '\n')
1213                         break;
1214         }
1215
1216         strbuf_addstr(&sb, mine.buf + !!cp);
1217 exit:
1218         strbuf_release(&mine);
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         assert(!state->author_name);
1324         state->author_name = strbuf_detach(&author_name, NULL);
1325
1326         assert(!state->author_email);
1327         state->author_email = strbuf_detach(&author_email, NULL);
1328
1329         assert(!state->author_date);
1330         state->author_date = strbuf_detach(&author_date, NULL);
1331
1332         assert(!state->msg);
1333         state->msg = strbuf_detach(&msg, &state->msg_len);
1334
1335 finish:
1336         strbuf_release(&msg);
1337         strbuf_release(&author_date);
1338         strbuf_release(&author_email);
1339         strbuf_release(&author_name);
1340         strbuf_release(&sb);
1341         clear_mailinfo(&mi);
1342         return ret;
1343 }
1344
1345 /**
1346  * Sets commit_id to the commit hash where the mail was generated from.
1347  * Returns 0 on success, -1 on failure.
1348  */
1349 static int get_mail_commit_oid(struct object_id *commit_id, const char *mail)
1350 {
1351         struct strbuf sb = STRBUF_INIT;
1352         FILE *fp = xfopen(mail, "r");
1353         const char *x;
1354
1355         if (strbuf_getline_lf(&sb, fp))
1356                 return -1;
1357
1358         if (!skip_prefix(sb.buf, "From ", &x))
1359                 return -1;
1360
1361         if (get_oid_hex(x, commit_id) < 0)
1362                 return -1;
1363
1364         strbuf_release(&sb);
1365         fclose(fp);
1366         return 0;
1367 }
1368
1369 /**
1370  * Sets state->msg, state->author_name, state->author_email, state->author_date
1371  * to the commit's respective info.
1372  */
1373 static void get_commit_info(struct am_state *state, struct commit *commit)
1374 {
1375         const char *buffer, *ident_line, *msg;
1376         size_t ident_len;
1377         struct ident_split id;
1378
1379         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1380
1381         ident_line = find_commit_header(buffer, "author", &ident_len);
1382
1383         if (split_ident_line(&id, ident_line, ident_len) < 0)
1384                 die(_("invalid ident line: %.*s"), (int)ident_len, ident_line);
1385
1386         assert(!state->author_name);
1387         if (id.name_begin)
1388                 state->author_name =
1389                         xmemdupz(id.name_begin, id.name_end - id.name_begin);
1390         else
1391                 state->author_name = xstrdup("");
1392
1393         assert(!state->author_email);
1394         if (id.mail_begin)
1395                 state->author_email =
1396                         xmemdupz(id.mail_begin, id.mail_end - id.mail_begin);
1397         else
1398                 state->author_email = xstrdup("");
1399
1400         assert(!state->author_date);
1401         state->author_date = xstrdup(show_ident_date(&id, DATE_MODE(NORMAL)));
1402
1403         assert(!state->msg);
1404         msg = strstr(buffer, "\n\n");
1405         if (!msg)
1406                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1407         state->msg = xstrdup(msg + 2);
1408         state->msg_len = strlen(state->msg);
1409         unuse_commit_buffer(commit, buffer);
1410 }
1411
1412 /**
1413  * Writes `commit` as a patch to the state directory's "patch" file.
1414  */
1415 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1416 {
1417         struct rev_info rev_info;
1418         FILE *fp;
1419
1420         fp = xfopen(am_path(state, "patch"), "w");
1421         init_revisions(&rev_info, NULL);
1422         rev_info.diff = 1;
1423         rev_info.abbrev = 0;
1424         rev_info.disable_stdin = 1;
1425         rev_info.show_root_diff = 1;
1426         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1427         rev_info.no_commit_id = 1;
1428         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1429         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1430         rev_info.diffopt.use_color = 0;
1431         rev_info.diffopt.file = fp;
1432         rev_info.diffopt.close_file = 1;
1433         add_pending_object(&rev_info, &commit->object, "");
1434         diff_setup_done(&rev_info.diffopt);
1435         log_tree_commit(&rev_info, commit);
1436 }
1437
1438 /**
1439  * Writes the diff of the index against HEAD as a patch to the state
1440  * directory's "patch" file.
1441  */
1442 static void write_index_patch(const struct am_state *state)
1443 {
1444         struct tree *tree;
1445         struct object_id head;
1446         struct rev_info rev_info;
1447         FILE *fp;
1448
1449         if (!get_sha1_tree("HEAD", head.hash))
1450                 tree = lookup_tree(&head);
1451         else
1452                 tree = lookup_tree(&empty_tree_oid);
1453
1454         fp = xfopen(am_path(state, "patch"), "w");
1455         init_revisions(&rev_info, NULL);
1456         rev_info.diff = 1;
1457         rev_info.disable_stdin = 1;
1458         rev_info.no_commit_id = 1;
1459         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1460         rev_info.diffopt.use_color = 0;
1461         rev_info.diffopt.file = fp;
1462         rev_info.diffopt.close_file = 1;
1463         add_pending_object(&rev_info, &tree->object, "");
1464         diff_setup_done(&rev_info.diffopt);
1465         run_diff_index(&rev_info, 1);
1466 }
1467
1468 /**
1469  * Like parse_mail(), but parses the mail by looking up its commit ID
1470  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1471  * of patches.
1472  *
1473  * state->orig_commit will be set to the original commit ID.
1474  *
1475  * Will always return 0 as the patch should never be skipped.
1476  */
1477 static int parse_mail_rebase(struct am_state *state, const char *mail)
1478 {
1479         struct commit *commit;
1480         struct object_id commit_oid;
1481
1482         if (get_mail_commit_oid(&commit_oid, mail) < 0)
1483                 die(_("could not parse %s"), mail);
1484
1485         commit = lookup_commit_or_die(&commit_oid, mail);
1486
1487         get_commit_info(state, commit);
1488
1489         write_commit_patch(state, commit);
1490
1491         oidcpy(&state->orig_commit, &commit_oid);
1492         write_state_text(state, "original-commit", oid_to_hex(&commit_oid));
1493
1494         return 0;
1495 }
1496
1497 /**
1498  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1499  * `index_file` is not NULL, the patch will be applied to that index.
1500  */
1501 static int run_apply(const struct am_state *state, const char *index_file)
1502 {
1503         struct argv_array apply_paths = ARGV_ARRAY_INIT;
1504         struct argv_array apply_opts = ARGV_ARRAY_INIT;
1505         struct apply_state apply_state;
1506         int res, opts_left;
1507         static struct lock_file lock_file;
1508         int force_apply = 0;
1509         int options = 0;
1510
1511         if (init_apply_state(&apply_state, NULL, &lock_file))
1512                 die("BUG: init_apply_state() failed");
1513
1514         argv_array_push(&apply_opts, "apply");
1515         argv_array_pushv(&apply_opts, state->git_apply_opts.argv);
1516
1517         opts_left = apply_parse_options(apply_opts.argc, apply_opts.argv,
1518                                         &apply_state, &force_apply, &options,
1519                                         NULL);
1520
1521         if (opts_left != 0)
1522                 die("unknown option passed through to git apply");
1523
1524         if (index_file) {
1525                 apply_state.index_file = index_file;
1526                 apply_state.cached = 1;
1527         } else
1528                 apply_state.check_index = 1;
1529
1530         /*
1531          * If we are allowed to fall back on 3-way merge, don't give false
1532          * errors during the initial attempt.
1533          */
1534         if (state->threeway && !index_file)
1535                 apply_state.apply_verbosity = verbosity_silent;
1536
1537         if (check_apply_state(&apply_state, force_apply))
1538                 die("BUG: check_apply_state() failed");
1539
1540         argv_array_push(&apply_paths, am_path(state, "patch"));
1541
1542         res = apply_all_patches(&apply_state, apply_paths.argc, apply_paths.argv, options);
1543
1544         argv_array_clear(&apply_paths);
1545         argv_array_clear(&apply_opts);
1546         clear_apply_state(&apply_state);
1547
1548         if (res)
1549                 return res;
1550
1551         if (index_file) {
1552                 /* Reload index as apply_all_patches() will have modified it. */
1553                 discard_cache();
1554                 read_cache_from(index_file);
1555         }
1556
1557         return 0;
1558 }
1559
1560 /**
1561  * Builds an index that contains just the blobs needed for a 3way merge.
1562  */
1563 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1564 {
1565         struct child_process cp = CHILD_PROCESS_INIT;
1566
1567         cp.git_cmd = 1;
1568         argv_array_push(&cp.args, "apply");
1569         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1570         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1571         argv_array_push(&cp.args, am_path(state, "patch"));
1572
1573         if (run_command(&cp))
1574                 return -1;
1575
1576         return 0;
1577 }
1578
1579 /**
1580  * Attempt a threeway merge, using index_path as the temporary index.
1581  */
1582 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1583 {
1584         struct object_id orig_tree, their_tree, our_tree;
1585         const struct object_id *bases[1] = { &orig_tree };
1586         struct merge_options o;
1587         struct commit *result;
1588         char *their_tree_name;
1589
1590         if (get_oid("HEAD", &our_tree) < 0)
1591                 hashcpy(our_tree.hash, EMPTY_TREE_SHA1_BIN);
1592
1593         if (build_fake_ancestor(state, index_path))
1594                 return error("could not build fake ancestor");
1595
1596         discard_cache();
1597         read_cache_from(index_path);
1598
1599         if (write_index_as_tree(orig_tree.hash, &the_index, index_path, 0, NULL))
1600                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1601
1602         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1603
1604         if (!state->quiet) {
1605                 /*
1606                  * List paths that needed 3-way fallback, so that the user can
1607                  * review them with extra care to spot mismerges.
1608                  */
1609                 struct rev_info rev_info;
1610                 const char *diff_filter_str = "--diff-filter=AM";
1611
1612                 init_revisions(&rev_info, NULL);
1613                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1614                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1615                 add_pending_oid(&rev_info, "HEAD", &our_tree, 0);
1616                 diff_setup_done(&rev_info.diffopt);
1617                 run_diff_index(&rev_info, 1);
1618         }
1619
1620         if (run_apply(state, index_path))
1621                 return error(_("Did you hand edit your patch?\n"
1622                                 "It does not apply to blobs recorded in its index."));
1623
1624         if (write_index_as_tree(their_tree.hash, &the_index, index_path, 0, NULL))
1625                 return error("could not write tree");
1626
1627         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1628
1629         discard_cache();
1630         read_cache();
1631
1632         /*
1633          * This is not so wrong. Depending on which base we picked, orig_tree
1634          * may be wildly different from ours, but their_tree has the same set of
1635          * wildly different changes in parts the patch did not touch, so
1636          * recursive ends up canceling them, saying that we reverted all those
1637          * changes.
1638          */
1639
1640         init_merge_options(&o);
1641
1642         o.branch1 = "HEAD";
1643         their_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
1644         o.branch2 = their_tree_name;
1645
1646         if (state->quiet)
1647                 o.verbosity = 0;
1648
1649         if (merge_recursive_generic(&o, &our_tree, &their_tree, 1, bases, &result)) {
1650                 rerere(state->allow_rerere_autoupdate);
1651                 free(their_tree_name);
1652                 return error(_("Failed to merge in the changes."));
1653         }
1654
1655         free(their_tree_name);
1656         return 0;
1657 }
1658
1659 /**
1660  * Commits the current index with state->msg as the commit message and
1661  * state->author_name, state->author_email and state->author_date as the author
1662  * information.
1663  */
1664 static void do_commit(const struct am_state *state)
1665 {
1666         struct object_id tree, parent, commit;
1667         const struct object_id *old_oid;
1668         struct commit_list *parents = NULL;
1669         const char *reflog_msg, *author;
1670         struct strbuf sb = STRBUF_INIT;
1671
1672         if (run_hook_le(NULL, "pre-applypatch", NULL))
1673                 exit(1);
1674
1675         if (write_cache_as_tree(tree.hash, 0, NULL))
1676                 die(_("git write-tree failed to write a tree"));
1677
1678         if (!get_sha1_commit("HEAD", parent.hash)) {
1679                 old_oid = &parent;
1680                 commit_list_insert(lookup_commit(&parent), &parents);
1681         } else {
1682                 old_oid = NULL;
1683                 say(state, stderr, _("applying to an empty history"));
1684         }
1685
1686         author = fmt_ident(state->author_name, state->author_email,
1687                         state->ignore_date ? NULL : state->author_date,
1688                         IDENT_STRICT);
1689
1690         if (state->committer_date_is_author_date)
1691                 setenv("GIT_COMMITTER_DATE",
1692                         state->ignore_date ? "" : state->author_date, 1);
1693
1694         if (commit_tree(state->msg, state->msg_len, tree.hash, parents, commit.hash,
1695                                 author, state->sign_commit))
1696                 die(_("failed to write commit object"));
1697
1698         reflog_msg = getenv("GIT_REFLOG_ACTION");
1699         if (!reflog_msg)
1700                 reflog_msg = "am";
1701
1702         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1703                         state->msg);
1704
1705         update_ref_oid(sb.buf, "HEAD", &commit, old_oid, 0,
1706                         UPDATE_REFS_DIE_ON_ERR);
1707
1708         if (state->rebasing) {
1709                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1710
1711                 assert(!is_null_oid(&state->orig_commit));
1712                 fprintf(fp, "%s ", oid_to_hex(&state->orig_commit));
1713                 fprintf(fp, "%s\n", oid_to_hex(&commit));
1714                 fclose(fp);
1715         }
1716
1717         run_hook_le(NULL, "post-applypatch", NULL);
1718
1719         strbuf_release(&sb);
1720 }
1721
1722 /**
1723  * Validates the am_state for resuming -- the "msg" and authorship fields must
1724  * be filled up.
1725  */
1726 static void validate_resume_state(const struct am_state *state)
1727 {
1728         if (!state->msg)
1729                 die(_("cannot resume: %s does not exist."),
1730                         am_path(state, "final-commit"));
1731
1732         if (!state->author_name || !state->author_email || !state->author_date)
1733                 die(_("cannot resume: %s does not exist."),
1734                         am_path(state, "author-script"));
1735 }
1736
1737 /**
1738  * Interactively prompt the user on whether the current patch should be
1739  * applied.
1740  *
1741  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1742  * skip it.
1743  */
1744 static int do_interactive(struct am_state *state)
1745 {
1746         assert(state->msg);
1747
1748         if (!isatty(0))
1749                 die(_("cannot be interactive without stdin connected to a terminal."));
1750
1751         for (;;) {
1752                 const char *reply;
1753
1754                 puts(_("Commit Body is:"));
1755                 puts("--------------------------");
1756                 printf("%s", state->msg);
1757                 puts("--------------------------");
1758
1759                 /*
1760                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1761                  * in your translation. The program will only accept English
1762                  * input at this point.
1763                  */
1764                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1765
1766                 if (!reply) {
1767                         continue;
1768                 } else if (*reply == 'y' || *reply == 'Y') {
1769                         return 0;
1770                 } else if (*reply == 'a' || *reply == 'A') {
1771                         state->interactive = 0;
1772                         return 0;
1773                 } else if (*reply == 'n' || *reply == 'N') {
1774                         return 1;
1775                 } else if (*reply == 'e' || *reply == 'E') {
1776                         struct strbuf msg = STRBUF_INIT;
1777
1778                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1779                                 free(state->msg);
1780                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1781                         }
1782                         strbuf_release(&msg);
1783                 } else if (*reply == 'v' || *reply == 'V') {
1784                         const char *pager = git_pager(1);
1785                         struct child_process cp = CHILD_PROCESS_INIT;
1786
1787                         if (!pager)
1788                                 pager = "cat";
1789                         prepare_pager_args(&cp, pager);
1790                         argv_array_push(&cp.args, am_path(state, "patch"));
1791                         run_command(&cp);
1792                 }
1793         }
1794 }
1795
1796 /**
1797  * Applies all queued mail.
1798  *
1799  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1800  * well as the state directory's "patch" file is used as-is for applying the
1801  * patch and committing it.
1802  */
1803 static void am_run(struct am_state *state, int resume)
1804 {
1805         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1806         struct strbuf sb = STRBUF_INIT;
1807
1808         unlink(am_path(state, "dirtyindex"));
1809
1810         refresh_and_write_cache();
1811
1812         if (index_has_changes(&sb)) {
1813                 write_state_bool(state, "dirtyindex", 1);
1814                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1815         }
1816
1817         strbuf_release(&sb);
1818
1819         while (state->cur <= state->last) {
1820                 const char *mail = am_path(state, msgnum(state));
1821                 int apply_status;
1822
1823                 reset_ident_date();
1824
1825                 if (!file_exists(mail))
1826                         goto next;
1827
1828                 if (resume) {
1829                         validate_resume_state(state);
1830                 } else {
1831                         int skip;
1832
1833                         if (state->rebasing)
1834                                 skip = parse_mail_rebase(state, mail);
1835                         else
1836                                 skip = parse_mail(state, mail);
1837
1838                         if (skip)
1839                                 goto next; /* mail should be skipped */
1840
1841                         if (state->signoff)
1842                                 am_append_signoff(state);
1843
1844                         write_author_script(state);
1845                         write_commit_msg(state);
1846                 }
1847
1848                 if (state->interactive && do_interactive(state))
1849                         goto next;
1850
1851                 if (run_applypatch_msg_hook(state))
1852                         exit(1);
1853
1854                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1855
1856                 apply_status = run_apply(state, NULL);
1857
1858                 if (apply_status && state->threeway) {
1859                         struct strbuf sb = STRBUF_INIT;
1860
1861                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1862                         apply_status = fall_back_threeway(state, sb.buf);
1863                         strbuf_release(&sb);
1864
1865                         /*
1866                          * Applying the patch to an earlier tree and merging
1867                          * the result may have produced the same tree as ours.
1868                          */
1869                         if (!apply_status && !index_has_changes(NULL)) {
1870                                 say(state, stdout, _("No changes -- Patch already applied."));
1871                                 goto next;
1872                         }
1873                 }
1874
1875                 if (apply_status) {
1876                         int advice_amworkdir = 1;
1877
1878                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1879                                 linelen(state->msg), state->msg);
1880
1881                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1882
1883                         if (advice_amworkdir)
1884                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1885                                                 am_path(state, "patch"));
1886
1887                         die_user_resolve(state);
1888                 }
1889
1890                 do_commit(state);
1891
1892 next:
1893                 am_next(state);
1894
1895                 if (resume)
1896                         am_load(state);
1897                 resume = 0;
1898         }
1899
1900         if (!is_empty_file(am_path(state, "rewritten"))) {
1901                 assert(state->rebasing);
1902                 copy_notes_for_rebase(state);
1903                 run_post_rewrite_hook(state);
1904         }
1905
1906         /*
1907          * In rebasing mode, it's up to the caller to take care of
1908          * housekeeping.
1909          */
1910         if (!state->rebasing) {
1911                 am_destroy(state);
1912                 close_all_packs();
1913                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1914         }
1915 }
1916
1917 /**
1918  * Resume the current am session after patch application failure. The user did
1919  * all the hard work, and we do not have to do any patch application. Just
1920  * trust and commit what the user has in the index and working tree.
1921  */
1922 static void am_resolve(struct am_state *state)
1923 {
1924         validate_resume_state(state);
1925
1926         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1927
1928         if (!index_has_changes(NULL)) {
1929                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1930                         "If there is nothing left to stage, chances are that something else\n"
1931                         "already introduced the same changes; you might want to skip this patch."));
1932                 die_user_resolve(state);
1933         }
1934
1935         if (unmerged_cache()) {
1936                 printf_ln(_("You still have unmerged paths in your index.\n"
1937                         "Did you forget to use 'git add'?"));
1938                 die_user_resolve(state);
1939         }
1940
1941         if (state->interactive) {
1942                 write_index_patch(state);
1943                 if (do_interactive(state))
1944                         goto next;
1945         }
1946
1947         rerere(0);
1948
1949         do_commit(state);
1950
1951 next:
1952         am_next(state);
1953         am_load(state);
1954         am_run(state, 0);
1955 }
1956
1957 /**
1958  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1959  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1960  * failure.
1961  */
1962 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1963 {
1964         struct lock_file *lock_file;
1965         struct unpack_trees_options opts;
1966         struct tree_desc t[2];
1967
1968         if (parse_tree(head) || parse_tree(remote))
1969                 return -1;
1970
1971         lock_file = xcalloc(1, sizeof(struct lock_file));
1972         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
1973
1974         refresh_cache(REFRESH_QUIET);
1975
1976         memset(&opts, 0, sizeof(opts));
1977         opts.head_idx = 1;
1978         opts.src_index = &the_index;
1979         opts.dst_index = &the_index;
1980         opts.update = 1;
1981         opts.merge = 1;
1982         opts.reset = reset;
1983         opts.fn = twoway_merge;
1984         init_tree_desc(&t[0], head->buffer, head->size);
1985         init_tree_desc(&t[1], remote->buffer, remote->size);
1986
1987         if (unpack_trees(2, t, &opts)) {
1988                 rollback_lock_file(lock_file);
1989                 return -1;
1990         }
1991
1992         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1993                 die(_("unable to write new index file"));
1994
1995         return 0;
1996 }
1997
1998 /**
1999  * Merges a tree into the index. The index's stat info will take precedence
2000  * over the merged tree's. Returns 0 on success, -1 on failure.
2001  */
2002 static int merge_tree(struct tree *tree)
2003 {
2004         struct lock_file *lock_file;
2005         struct unpack_trees_options opts;
2006         struct tree_desc t[1];
2007
2008         if (parse_tree(tree))
2009                 return -1;
2010
2011         lock_file = xcalloc(1, sizeof(struct lock_file));
2012         hold_locked_index(lock_file, LOCK_DIE_ON_ERROR);
2013
2014         memset(&opts, 0, sizeof(opts));
2015         opts.head_idx = 1;
2016         opts.src_index = &the_index;
2017         opts.dst_index = &the_index;
2018         opts.merge = 1;
2019         opts.fn = oneway_merge;
2020         init_tree_desc(&t[0], tree->buffer, tree->size);
2021
2022         if (unpack_trees(1, t, &opts)) {
2023                 rollback_lock_file(lock_file);
2024                 return -1;
2025         }
2026
2027         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2028                 die(_("unable to write new index file"));
2029
2030         return 0;
2031 }
2032
2033 /**
2034  * Clean the index without touching entries that are not modified between
2035  * `head` and `remote`.
2036  */
2037 static int clean_index(const struct object_id *head, const struct object_id *remote)
2038 {
2039         struct tree *head_tree, *remote_tree, *index_tree;
2040         struct object_id index;
2041
2042         head_tree = parse_tree_indirect(head);
2043         if (!head_tree)
2044                 return error(_("Could not parse object '%s'."), oid_to_hex(head));
2045
2046         remote_tree = parse_tree_indirect(remote);
2047         if (!remote_tree)
2048                 return error(_("Could not parse object '%s'."), oid_to_hex(remote));
2049
2050         read_cache_unmerged();
2051
2052         if (fast_forward_to(head_tree, head_tree, 1))
2053                 return -1;
2054
2055         if (write_cache_as_tree(index.hash, 0, NULL))
2056                 return -1;
2057
2058         index_tree = parse_tree_indirect(&index);
2059         if (!index_tree)
2060                 return error(_("Could not parse object '%s'."), oid_to_hex(&index));
2061
2062         if (fast_forward_to(index_tree, remote_tree, 0))
2063                 return -1;
2064
2065         if (merge_tree(remote_tree))
2066                 return -1;
2067
2068         remove_branch_state();
2069
2070         return 0;
2071 }
2072
2073 /**
2074  * Resets rerere's merge resolution metadata.
2075  */
2076 static void am_rerere_clear(void)
2077 {
2078         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2079         rerere_clear(&merge_rr);
2080         string_list_clear(&merge_rr, 1);
2081 }
2082
2083 /**
2084  * Resume the current am session by skipping the current patch.
2085  */
2086 static void am_skip(struct am_state *state)
2087 {
2088         struct object_id head;
2089
2090         am_rerere_clear();
2091
2092         if (get_oid("HEAD", &head))
2093                 hashcpy(head.hash, EMPTY_TREE_SHA1_BIN);
2094
2095         if (clean_index(&head, &head))
2096                 die(_("failed to clean index"));
2097
2098         am_next(state);
2099         am_load(state);
2100         am_run(state, 0);
2101 }
2102
2103 /**
2104  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2105  *
2106  * It is not safe to reset HEAD when:
2107  * 1. git-am previously failed because the index was dirty.
2108  * 2. HEAD has moved since git-am previously failed.
2109  */
2110 static int safe_to_abort(const struct am_state *state)
2111 {
2112         struct strbuf sb = STRBUF_INIT;
2113         struct object_id abort_safety, head;
2114
2115         if (file_exists(am_path(state, "dirtyindex")))
2116                 return 0;
2117
2118         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2119                 if (get_oid_hex(sb.buf, &abort_safety))
2120                         die(_("could not parse %s"), am_path(state, "abort-safety"));
2121         } else
2122                 oidclr(&abort_safety);
2123
2124         if (get_oid("HEAD", &head))
2125                 oidclr(&head);
2126
2127         if (!oidcmp(&head, &abort_safety))
2128                 return 1;
2129
2130         warning(_("You seem to have moved HEAD since the last 'am' failure.\n"
2131                 "Not rewinding to ORIG_HEAD"));
2132
2133         return 0;
2134 }
2135
2136 /**
2137  * Aborts the current am session if it is safe to do so.
2138  */
2139 static void am_abort(struct am_state *state)
2140 {
2141         struct object_id curr_head, orig_head;
2142         int has_curr_head, has_orig_head;
2143         char *curr_branch;
2144
2145         if (!safe_to_abort(state)) {
2146                 am_destroy(state);
2147                 return;
2148         }
2149
2150         am_rerere_clear();
2151
2152         curr_branch = resolve_refdup("HEAD", 0, curr_head.hash, NULL);
2153         has_curr_head = curr_branch && !is_null_oid(&curr_head);
2154         if (!has_curr_head)
2155                 hashcpy(curr_head.hash, EMPTY_TREE_SHA1_BIN);
2156
2157         has_orig_head = !get_oid("ORIG_HEAD", &orig_head);
2158         if (!has_orig_head)
2159                 hashcpy(orig_head.hash, EMPTY_TREE_SHA1_BIN);
2160
2161         clean_index(&curr_head, &orig_head);
2162
2163         if (has_orig_head)
2164                 update_ref_oid("am --abort", "HEAD", &orig_head,
2165                                 has_curr_head ? &curr_head : NULL, 0,
2166                                 UPDATE_REFS_DIE_ON_ERR);
2167         else if (curr_branch)
2168                 delete_ref(NULL, curr_branch, NULL, REF_NODEREF);
2169
2170         free(curr_branch);
2171         am_destroy(state);
2172 }
2173
2174 /**
2175  * parse_options() callback that validates and sets opt->value to the
2176  * PATCH_FORMAT_* enum value corresponding to `arg`.
2177  */
2178 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2179 {
2180         int *opt_value = opt->value;
2181
2182         if (!strcmp(arg, "mbox"))
2183                 *opt_value = PATCH_FORMAT_MBOX;
2184         else if (!strcmp(arg, "stgit"))
2185                 *opt_value = PATCH_FORMAT_STGIT;
2186         else if (!strcmp(arg, "stgit-series"))
2187                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2188         else if (!strcmp(arg, "hg"))
2189                 *opt_value = PATCH_FORMAT_HG;
2190         else if (!strcmp(arg, "mboxrd"))
2191                 *opt_value = PATCH_FORMAT_MBOXRD;
2192         else
2193                 return error(_("Invalid value for --patch-format: %s"), arg);
2194         return 0;
2195 }
2196
2197 enum resume_mode {
2198         RESUME_FALSE = 0,
2199         RESUME_APPLY,
2200         RESUME_RESOLVED,
2201         RESUME_SKIP,
2202         RESUME_ABORT
2203 };
2204
2205 static int git_am_config(const char *k, const char *v, void *cb)
2206 {
2207         int status;
2208
2209         status = git_gpg_config(k, v, NULL);
2210         if (status)
2211                 return status;
2212
2213         return git_default_config(k, v, NULL);
2214 }
2215
2216 int cmd_am(int argc, const char **argv, const char *prefix)
2217 {
2218         struct am_state state;
2219         int binary = -1;
2220         int keep_cr = -1;
2221         int patch_format = PATCH_FORMAT_UNKNOWN;
2222         enum resume_mode resume = RESUME_FALSE;
2223         int in_progress;
2224
2225         const char * const usage[] = {
2226                 N_("git am [<options>] [(<mbox> | <Maildir>)...]"),
2227                 N_("git am [<options>] (--continue | --skip | --abort)"),
2228                 NULL
2229         };
2230
2231         struct option options[] = {
2232                 OPT_BOOL('i', "interactive", &state.interactive,
2233                         N_("run interactively")),
2234                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2235                         N_("historical option -- no-op")),
2236                 OPT_BOOL('3', "3way", &state.threeway,
2237                         N_("allow fall back on 3way merging if needed")),
2238                 OPT__QUIET(&state.quiet, N_("be quiet")),
2239                 OPT_SET_INT('s', "signoff", &state.signoff,
2240                         N_("add a Signed-off-by line to the commit message"),
2241                         SIGNOFF_EXPLICIT),
2242                 OPT_BOOL('u', "utf8", &state.utf8,
2243                         N_("recode into utf8 (default)")),
2244                 OPT_SET_INT('k', "keep", &state.keep,
2245                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2246                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2247                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2248                 OPT_BOOL('m', "message-id", &state.message_id,
2249                         N_("pass -m flag to git-mailinfo")),
2250                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2251                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2252                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2253                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2254                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2255                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2256                 OPT_BOOL('c', "scissors", &state.scissors,
2257                         N_("strip everything before a scissors line")),
2258                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2259                         N_("pass it through git-apply"),
2260                         0),
2261                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2262                         N_("pass it through git-apply"),
2263                         PARSE_OPT_NOARG),
2264                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2265                         N_("pass it through git-apply"),
2266                         PARSE_OPT_NOARG),
2267                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2268                         N_("pass it through git-apply"),
2269                         0),
2270                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2271                         N_("pass it through git-apply"),
2272                         0),
2273                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2274                         N_("pass it through git-apply"),
2275                         0),
2276                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2277                         N_("pass it through git-apply"),
2278                         0),
2279                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2280                         N_("pass it through git-apply"),
2281                         0),
2282                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2283                         N_("format the patch(es) are in"),
2284                         parse_opt_patchformat),
2285                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2286                         N_("pass it through git-apply"),
2287                         PARSE_OPT_NOARG),
2288                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2289                         N_("override error message when patch failure occurs")),
2290                 OPT_CMDMODE(0, "continue", &resume,
2291                         N_("continue applying patches after resolving a conflict"),
2292                         RESUME_RESOLVED),
2293                 OPT_CMDMODE('r', "resolved", &resume,
2294                         N_("synonyms for --continue"),
2295                         RESUME_RESOLVED),
2296                 OPT_CMDMODE(0, "skip", &resume,
2297                         N_("skip the current patch"),
2298                         RESUME_SKIP),
2299                 OPT_CMDMODE(0, "abort", &resume,
2300                         N_("restore the original branch and abort the patching operation."),
2301                         RESUME_ABORT),
2302                 OPT_BOOL(0, "committer-date-is-author-date",
2303                         &state.committer_date_is_author_date,
2304                         N_("lie about committer date")),
2305                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2306                         N_("use current timestamp for author date")),
2307                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2308                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2309                   N_("GPG-sign commits"),
2310                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2311                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2312                         N_("(internal use for git-rebase)")),
2313                 OPT_END()
2314         };
2315
2316         git_config(git_am_config, NULL);
2317
2318         am_state_init(&state);
2319
2320         in_progress = am_in_progress(&state);
2321         if (in_progress)
2322                 am_load(&state);
2323
2324         argc = parse_options(argc, argv, prefix, options, usage, 0);
2325
2326         if (binary >= 0)
2327                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2328                                 "it will be removed. Please do not use it anymore."));
2329
2330         /* Ensure a valid committer ident can be constructed */
2331         git_committer_info(IDENT_STRICT);
2332
2333         if (read_index_preload(&the_index, NULL) < 0)
2334                 die(_("failed to read the index"));
2335
2336         if (in_progress) {
2337                 /*
2338                  * Catch user error to feed us patches when there is a session
2339                  * in progress:
2340                  *
2341                  * 1. mbox path(s) are provided on the command-line.
2342                  * 2. stdin is not a tty: the user is trying to feed us a patch
2343                  *    from standard input. This is somewhat unreliable -- stdin
2344                  *    could be /dev/null for example and the caller did not
2345                  *    intend to feed us a patch but wanted to continue
2346                  *    unattended.
2347                  */
2348                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2349                         die(_("previous rebase directory %s still exists but mbox given."),
2350                                 state.dir);
2351
2352                 if (resume == RESUME_FALSE)
2353                         resume = RESUME_APPLY;
2354
2355                 if (state.signoff == SIGNOFF_EXPLICIT)
2356                         am_append_signoff(&state);
2357         } else {
2358                 struct argv_array paths = ARGV_ARRAY_INIT;
2359                 int i;
2360
2361                 /*
2362                  * Handle stray state directory in the independent-run case. In
2363                  * the --rebasing case, it is up to the caller to take care of
2364                  * stray directories.
2365                  */
2366                 if (file_exists(state.dir) && !state.rebasing) {
2367                         if (resume == RESUME_ABORT) {
2368                                 am_destroy(&state);
2369                                 am_state_release(&state);
2370                                 return 0;
2371                         }
2372
2373                         die(_("Stray %s directory found.\n"
2374                                 "Use \"git am --abort\" to remove it."),
2375                                 state.dir);
2376                 }
2377
2378                 if (resume)
2379                         die(_("Resolve operation not in progress, we are not resuming."));
2380
2381                 for (i = 0; i < argc; i++) {
2382                         if (is_absolute_path(argv[i]) || !prefix)
2383                                 argv_array_push(&paths, argv[i]);
2384                         else
2385                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2386                 }
2387
2388                 am_setup(&state, patch_format, paths.argv, keep_cr);
2389
2390                 argv_array_clear(&paths);
2391         }
2392
2393         switch (resume) {
2394         case RESUME_FALSE:
2395                 am_run(&state, 0);
2396                 break;
2397         case RESUME_APPLY:
2398                 am_run(&state, 1);
2399                 break;
2400         case RESUME_RESOLVED:
2401                 am_resolve(&state);
2402                 break;
2403         case RESUME_SKIP:
2404                 am_skip(&state);
2405                 break;
2406         case RESUME_ABORT:
2407                 am_abort(&state);
2408                 break;
2409         default:
2410                 die("BUG: invalid resume value");
2411         }
2412
2413         am_state_release(&state);
2414
2415         return 0;
2416 }