builtin/revert.c

   1 #include "cache.h"
   2 #include "builtin.h"
   3 #include "object.h"
   4 #include "commit.h"
   5 #include "tag.h"
   6 #include "run-command.h"
   7 #include "exec_cmd.h"
   8 #include "utf8.h"
   9 #include "parse-options.h"
  10 #include "cache-tree.h"
  11 #include "diff.h"
  12 #include "revision.h"
  13 #include "rerere.h"
  14 #include "merge-recursive.h"
  15 #include "refs.h"
  16 #include "dir.h"
  17
  18 /*
  19  * This implements the builtins revert and cherry-pick.
  20  *
  21  * Copyright (c) 2007 Johannes E. Schindelin
  22  *
  23  * Based on git-revert.sh, which is
  24  *
  25  * Copyright (c) 2005 Linus Torvalds
  26  * Copyright (c) 2005 Junio C Hamano
  27  */
  28
  29 static const char * const revert_usage[] = {
  30         "git revert [options] <commit-ish>",
  31         NULL
  32 };
  33
  34 static const char * const cherry_pick_usage[] = {
  35         "git cherry-pick [options] <commit-ish>",
  36         NULL
  37 };
  38
  39 enum replay_action { REVERT, CHERRY_PICK };
  40
  41 struct replay_opts {
  42         enum replay_action action;
  43
  44         /* Boolean options */
  45         int edit;
  46         int record_origin;
  47         int no_commit;
  48         int signoff;
  49         int allow_ff;
  50         int allow_rerere_auto;
  51
  52         int mainline;
  53         int commit_argc;
  54         const char **commit_argv;
  55
  56         /* Merge strategy */
  57         const char *strategy;
  58         const char **xopts;
  59         size_t xopts_nr, xopts_alloc;
  60 };
  61
  62 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
  63
  64 #define SEQ_DIR         "sequencer"
  65 #define SEQ_HEAD_FILE   "sequencer/head"
  66 #define SEQ_TODO_FILE   "sequencer/todo"
  67 #define SEQ_OPTS_FILE   "sequencer/opts"
  68
  69 static const char *action_name(const struct replay_opts *opts)
  70 {
  71         return opts->action == REVERT ? "revert" : "cherry-pick";
  72 }
  73
  74 static char *get_encoding(const char *message);
  75
  76 static const char * const *revert_or_cherry_pick_usage(struct replay_opts *opts)
  77 {
  78         return opts->action == REVERT ? revert_usage : cherry_pick_usage;
  79 }
  80
  81 static int option_parse_x(const struct option *opt,
  82                           const char *arg, int unset)
  83 {
  84         struct replay_opts **opts_ptr = opt->value;
  85         struct replay_opts *opts = *opts_ptr;
  86
  87         if (unset)
  88                 return 0;
  89
  90         ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
  91         opts->xopts[opts->xopts_nr++] = xstrdup(arg);
  92         return 0;
  93 }
  94
  95 static void verify_opt_compatible(const char *me, const char *base_opt, ...)
  96 {
  97         const char *this_opt;
  98         va_list ap;
  99
 100         va_start(ap, base_opt);
 101         while ((this_opt = va_arg(ap, const char *))) {
 102                 if (va_arg(ap, int))
 103                         break;
 104         }
 105         va_end(ap);
 106
 107         if (this_opt)
 108                 die(_("%s: %s cannot be used with %s"), me, this_opt, base_opt);
 109 }
 110
 111 static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 112 {
 113         const char * const * usage_str = revert_or_cherry_pick_usage(opts);
 114         const char *me = action_name(opts);
 115         int noop;
 116         struct option options[] = {
 117                 OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
 118                 OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
 119                 { OPTION_BOOLEAN, 'r', NULL, &noop, NULL, "no-op (backward compatibility)",
 120                   PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 0 },
 121                 OPT_BOOLEAN('s', "signoff", &opts->signoff, "add Signed-off-by:"),
 122                 OPT_INTEGER('m', "mainline", &opts->mainline, "parent number"),
 123                 OPT_RERERE_AUTOUPDATE(&opts->allow_rerere_auto),
 124                 OPT_STRING(0, "strategy", &opts->strategy, "strategy", "merge strategy"),
 125                 OPT_CALLBACK('X', "strategy-option", &opts, "option",
 126                         "option for merge strategy", option_parse_x),
 127                 OPT_END(),
 128                 OPT_END(),
 129                 OPT_END(),
 130         };
 131
 132         if (opts->action == CHERRY_PICK) {
 133                 struct option cp_extra[] = {
 134                         OPT_BOOLEAN('x', NULL, &opts->record_origin, "append commit name"),
 135                         OPT_BOOLEAN(0, "ff", &opts->allow_ff, "allow fast-forward"),
 136                         OPT_END(),
 137                 };
 138                 if (parse_options_concat(options, ARRAY_SIZE(options), cp_extra))
 139                         die(_("program error"));
 140         }
 141
 142         opts->commit_argc = parse_options(argc, argv, NULL, options, usage_str,
 143                                         PARSE_OPT_KEEP_ARGV0 |
 144                                         PARSE_OPT_KEEP_UNKNOWN);
 145         if (opts->commit_argc < 2)
 146                 usage_with_options(usage_str, options);
 147
 148         if (opts->allow_ff)
 149                 verify_opt_compatible(me, "--ff",
 150                                 "--signoff", opts->signoff,
 151                                 "--no-commit", opts->no_commit,
 152                                 "-x", opts->record_origin,
 153                                 "--edit", opts->edit,
 154                                 NULL);
 155         opts->commit_argv = argv;
 156 }
 157
 158 struct commit_message {
 159         char *parent_label;
 160         const char *label;
 161         const char *subject;
 162         char *reencoded_message;
 163         const char *message;
 164 };
 165
 166 static int get_message(struct commit *commit, struct commit_message *out)
 167 {
 168         const char *encoding;
 169         const char *abbrev, *subject;
 170         int abbrev_len, subject_len;
 171         char *q;
 172
 173         if (!commit->buffer)
 174                 return -1;
 175         encoding = get_encoding(commit->buffer);
 176         if (!encoding)
 177                 encoding = "UTF-8";
 178         if (!git_commit_encoding)
 179                 git_commit_encoding = "UTF-8";
 180
 181         out->reencoded_message = NULL;
 182         out->message = commit->buffer;
 183         if (strcmp(encoding, git_commit_encoding))
 184                 out->reencoded_message = reencode_string(commit->buffer,
 185                                         git_commit_encoding, encoding);
 186         if (out->reencoded_message)
 187                 out->message = out->reencoded_message;
 188
 189         abbrev = find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV);
 190         abbrev_len = strlen(abbrev);
 191
 192         subject_len = find_commit_subject(out->message, &subject);
 193
 194         out->parent_label = xmalloc(strlen("parent of ") + abbrev_len +
 195                               strlen("... ") + subject_len + 1);
 196         q = out->parent_label;
 197         q = mempcpy(q, "parent of ", strlen("parent of "));
 198         out->label = q;
 199         q = mempcpy(q, abbrev, abbrev_len);
 200         q = mempcpy(q, "... ", strlen("... "));
 201         out->subject = q;
 202         q = mempcpy(q, subject, subject_len);
 203         *q = '\0';
 204         return 0;
 205 }
 206
 207 static void free_message(struct commit_message *msg)
 208 {
 209         free(msg->parent_label);
 210         free(msg->reencoded_message);
 211 }
 212
 213 static char *get_encoding(const char *message)
 214 {
 215         const char *p = message, *eol;
 216
 217         while (*p && *p != '\n') {
 218                 for (eol = p + 1; *eol && *eol != '\n'; eol++)
 219                         ; /* do nothing */
 220                 if (!prefixcmp(p, "encoding ")) {
 221                         char *result = xmalloc(eol - 8 - p);
 222                         strlcpy(result, p + 9, eol - 8 - p);
 223                         return result;
 224                 }
 225                 p = eol;
 226                 if (*p == '\n')
 227                         p++;
 228         }
 229         return NULL;
 230 }
 231
 232 static void write_cherry_pick_head(struct commit *commit)
 233 {
 234         int fd;
 235         struct strbuf buf = STRBUF_INIT;
 236
 237         strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 238
 239         fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
 240         if (fd < 0)
 241                 die_errno(_("Could not open '%s' for writing"),
 242                           git_path("CHERRY_PICK_HEAD"));
 243         if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
 244                 die_errno(_("Could not write to '%s'"), git_path("CHERRY_PICK_HEAD"));
 245         strbuf_release(&buf);
 246 }
 247
 248 static void print_advice(void)
 249 {
 250         char *msg = getenv("GIT_CHERRY_PICK_HELP");
 251
 252         if (msg) {
 253                 fprintf(stderr, "%s\n", msg);
 254                 /*
 255                  * A conflict has occured but the porcelain
 256                  * (typically rebase --interactive) wants to take care
 257                  * of the commit itself so remove CHERRY_PICK_HEAD
 258                  */
 259                 unlink(git_path("CHERRY_PICK_HEAD"));
 260                 return;
 261         }
 262
 263         advise("after resolving the conflicts, mark the corrected paths");
 264         advise("with 'git add <paths>' or 'git rm <paths>'");
 265         advise("and commit the result with 'git commit'");
 266 }
 267
 268 static void write_message(struct strbuf *msgbuf, const char *filename)
 269 {
 270         static struct lock_file msg_file;
 271
 272         int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 273                                                LOCK_DIE_ON_ERROR);
 274         if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
 275                 die_errno(_("Could not write to %s."), filename);
 276         strbuf_release(msgbuf);
 277         if (commit_lock_file(&msg_file) < 0)
 278                 die(_("Error wrapping up %s"), filename);
 279 }
 280
 281 static struct tree *empty_tree(void)
 282 {
 283         struct tree *tree = xcalloc(1, sizeof(struct tree));
 284
 285         tree->object.parsed = 1;
 286         tree->object.type = OBJ_TREE;
 287         pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 288         return tree;
 289 }
 290
 291 static NORETURN void die_dirty_index(struct replay_opts *opts)
 292 {
 293         if (read_cache_unmerged()) {
 294                 die_resolve_conflict(action_name(opts));
 295         } else {
 296                 if (advice_commit_before_merge) {
 297                         if (opts->action == REVERT)
 298                                 die(_("Your local changes would be overwritten by revert.\n"
 299                                           "Please, commit your changes or stash them to proceed."));
 300                         else
 301                                 die(_("Your local changes would be overwritten by cherry-pick.\n"
 302                                           "Please, commit your changes or stash them to proceed."));
 303                 } else {
 304                         if (opts->action == REVERT)
 305                                 die(_("Your local changes would be overwritten by revert.\n"));
 306                         else
 307                                 die(_("Your local changes would be overwritten by cherry-pick.\n"));
 308                 }
 309         }
 310 }
 311
 312 static int fast_forward_to(const unsigned char *to, const unsigned char *from)
 313 {
 314         struct ref_lock *ref_lock;
 315
 316         read_cache();
 317         if (checkout_fast_forward(from, to))
 318                 exit(1); /* the callee should have complained already */
 319         ref_lock = lock_any_ref_for_update("HEAD", from, 0);
 320         return write_ref_sha1(ref_lock, to, "cherry-pick");
 321 }
 322
 323 static int do_recursive_merge(struct commit *base, struct commit *next,
 324                               const char *base_label, const char *next_label,
 325                               unsigned char *head, struct strbuf *msgbuf,
 326                               struct replay_opts *opts)
 327 {
 328         struct merge_options o;
 329         struct tree *result, *next_tree, *base_tree, *head_tree;
 330         int clean, index_fd;
 331         const char **xopt;
 332         static struct lock_file index_lock;
 333
 334         index_fd = hold_locked_index(&index_lock, 1);
 335
 336         read_cache();
 337
 338         init_merge_options(&o);
 339         o.ancestor = base ? base_label : "(empty tree)";
 340         o.branch1 = "HEAD";
 341         o.branch2 = next ? next_label : "(empty tree)";
 342
 343         head_tree = parse_tree_indirect(head);
 344         next_tree = next ? next->tree : empty_tree();
 345         base_tree = base ? base->tree : empty_tree();
 346
 347         for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
 348                 parse_merge_opt(&o, *xopt);
 349
 350         clean = merge_trees(&o,
 351                             head_tree,
 352                             next_tree, base_tree, &result);
 353
 354         if (active_cache_changed &&
 355             (write_cache(index_fd, active_cache, active_nr) ||
 356              commit_locked_index(&index_lock)))
 357                 /* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 358                 die(_("%s: Unable to write new index file"), action_name(opts));
 359         rollback_lock_file(&index_lock);
 360
 361         if (!clean) {
 362                 int i;
 363                 strbuf_addstr(msgbuf, "\nConflicts:\n\n");
 364                 for (i = 0; i < active_nr;) {
 365                         struct cache_entry *ce = active_cache[i++];
 366                         if (ce_stage(ce)) {
 367                                 strbuf_addch(msgbuf, '\t');
 368                                 strbuf_addstr(msgbuf, ce->name);
 369                                 strbuf_addch(msgbuf, '\n');
 370                                 while (i < active_nr && !strcmp(ce->name,
 371                                                 active_cache[i]->name))
 372                                         i++;
 373                         }
 374                 }
 375         }
 376
 377         return !clean;
 378 }
 379
 380 /*
 381  * If we are cherry-pick, and if the merge did not result in
 382  * hand-editing, we will hit this commit and inherit the original
 383  * author date and name.
 384  * If we are revert, or if our cherry-pick results in a hand merge,
 385  * we had better say that the current user is responsible for that.
 386  */
 387 static int run_git_commit(const char *defmsg, struct replay_opts *opts)
 388 {
 389         /* 6 is max possible length of our args array including NULL */
 390         const char *args[6];
 391         int i = 0;
 392
 393         args[i++] = "commit";
 394         args[i++] = "-n";
 395         if (opts->signoff)
 396                 args[i++] = "-s";
 397         if (!opts->edit) {
 398                 args[i++] = "-F";
 399                 args[i++] = defmsg;
 400         }
 401         args[i] = NULL;
 402
 403         return run_command_v_opt(args, RUN_GIT_CMD);
 404 }
 405
 406 static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 407 {
 408         unsigned char head[20];
 409         struct commit *base, *next, *parent;
 410         const char *base_label, *next_label;
 411         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 412         char *defmsg = NULL;
 413         struct strbuf msgbuf = STRBUF_INIT;
 414         int res;
 415
 416         if (opts->no_commit) {
 417                 /*
 418                  * We do not intend to commit immediately.  We just want to
 419                  * merge the differences in, so let's compute the tree
 420                  * that represents the "current" state for merge-recursive
 421                  * to work on.
 422                  */
 423                 if (write_cache_as_tree(head, 0, NULL))
 424                         die (_("Your index file is unmerged."));
 425         } else {
 426                 if (get_sha1("HEAD", head))
 427                         die (_("You do not have a valid HEAD"));
 428                 if (index_differs_from("HEAD", 0))
 429                         die_dirty_index(opts);
 430         }
 431         discard_cache();
 432
 433         if (!commit->parents) {
 434                 parent = NULL;
 435         }
 436         else if (commit->parents->next) {
 437                 /* Reverting or cherry-picking a merge commit */
 438                 int cnt;
 439                 struct commit_list *p;
 440
 441                 if (!opts->mainline)
 442                         die(_("Commit %s is a merge but no -m option was given."),
 443                             sha1_to_hex(commit->object.sha1));
 444
 445                 for (cnt = 1, p = commit->parents;
 446                      cnt != opts->mainline && p;
 447                      cnt++)
 448                         p = p->next;
 449                 if (cnt != opts->mainline || !p)
 450                         die(_("Commit %s does not have parent %d"),
 451                             sha1_to_hex(commit->object.sha1), opts->mainline);
 452                 parent = p->item;
 453         } else if (0 < opts->mainline)
 454                 die(_("Mainline was specified but commit %s is not a merge."),
 455                     sha1_to_hex(commit->object.sha1));
 456         else
 457                 parent = commit->parents->item;
 458
 459         if (opts->allow_ff && parent && !hashcmp(parent->object.sha1, head))
 460                 return fast_forward_to(commit->object.sha1, head);
 461
 462         if (parent && parse_commit(parent) < 0)
 463                 /* TRANSLATORS: The first %s will be "revert" or
 464                    "cherry-pick", the second %s a SHA1 */
 465                 die(_("%s: cannot parse parent commit %s"),
 466                     action_name(opts), sha1_to_hex(parent->object.sha1));
 467
 468         if (get_message(commit, &msg) != 0)
 469                 die(_("Cannot get commit message for %s"),
 470                                 sha1_to_hex(commit->object.sha1));
 471
 472         /*
 473          * "commit" is an existing commit.  We would want to apply
 474          * the difference it introduces since its first parent "prev"
 475          * on top of the current HEAD if we are cherry-pick.  Or the
 476          * reverse of it if we are revert.
 477          */
 478
 479         defmsg = git_pathdup("MERGE_MSG");
 480
 481         if (opts->action == REVERT) {
 482                 base = commit;
 483                 base_label = msg.label;
 484                 next = parent;
 485                 next_label = msg.parent_label;
 486                 strbuf_addstr(&msgbuf, "Revert \"");
 487                 strbuf_addstr(&msgbuf, msg.subject);
 488                 strbuf_addstr(&msgbuf, "\"\n\nThis reverts commit ");
 489                 strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 490
 491                 if (commit->parents && commit->parents->next) {
 492                         strbuf_addstr(&msgbuf, ", reversing\nchanges made to ");
 493                         strbuf_addstr(&msgbuf, sha1_to_hex(parent->object.sha1));
 494                 }
 495                 strbuf_addstr(&msgbuf, ".\n");
 496         } else {
 497                 const char *p;
 498
 499                 base = parent;
 500                 base_label = msg.parent_label;
 501                 next = commit;
 502                 next_label = msg.label;
 503
 504                 /*
 505                  * Append the commit log message to msgbuf; it starts
 506                  * after the tree, parent, author, committer
 507                  * information followed by "\n\n".
 508                  */
 509                 p = strstr(msg.message, "\n\n");
 510                 if (p) {
 511                         p += 2;
 512                         strbuf_addstr(&msgbuf, p);
 513                 }
 514
 515                 if (opts->record_origin) {
 516                         strbuf_addstr(&msgbuf, "(cherry picked from commit ");
 517                         strbuf_addstr(&msgbuf, sha1_to_hex(commit->object.sha1));
 518                         strbuf_addstr(&msgbuf, ")\n");
 519                 }
 520                 if (!opts->no_commit)
 521                         write_cherry_pick_head(commit);
 522         }
 523
 524         if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REVERT) {
 525                 res = do_recursive_merge(base, next, base_label, next_label,
 526                                          head, &msgbuf, opts);
 527                 write_message(&msgbuf, defmsg);
 528         } else {
 529                 struct commit_list *common = NULL;
 530                 struct commit_list *remotes = NULL;
 531
 532                 write_message(&msgbuf, defmsg);
 533
 534                 commit_list_insert(base, &common);
 535                 commit_list_insert(next, &remotes);
 536                 res = try_merge_command(opts->strategy, opts->xopts_nr, opts->xopts,
 537                                         common, sha1_to_hex(head), remotes);
 538                 free_commit_list(common);
 539                 free_commit_list(remotes);
 540         }
 541
 542         if (res) {
 543                 error(opts->action == REVERT
 544                       ? _("could not revert %s... %s")
 545                       : _("could not apply %s... %s"),
 546                       find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV),
 547                       msg.subject);
 548                 print_advice();
 549                 rerere(opts->allow_rerere_auto);
 550         } else {
 551                 if (!opts->no_commit)
 552                         res = run_git_commit(defmsg, opts);
 553         }
 554
 555         free_message(&msg);
 556         free(defmsg);
 557
 558         return res;
 559 }
 560
 561 static void prepare_revs(struct rev_info *revs, struct replay_opts *opts)
 562 {
 563         int argc;
 564
 565         init_revisions(revs, NULL);
 566         revs->no_walk = 1;
 567         if (opts->action != REVERT)
 568                 revs->reverse = 1;
 569
 570         argc = setup_revisions(opts->commit_argc, opts->commit_argv, revs, NULL);
 571         if (argc > 1)
 572                 usage(*revert_or_cherry_pick_usage(opts));
 573
 574         if (prepare_revision_walk(revs))
 575                 die(_("revision walk setup failed"));
 576
 577         if (!revs->commits)
 578                 die(_("empty commit set passed"));
 579 }
 580
 581 static void read_and_refresh_cache(struct replay_opts *opts)
 582 {
 583         static struct lock_file index_lock;
 584         int index_fd = hold_locked_index(&index_lock, 0);
 585         if (read_index_preload(&the_index, NULL) < 0)
 586                 die(_("git %s: failed to read the index"), action_name(opts));
 587         refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
 588         if (the_index.cache_changed) {
 589                 if (write_index(&the_index, index_fd) ||
 590                     commit_locked_index(&index_lock))
 591                         die(_("git %s: failed to refresh the index"), action_name(opts));
 592         }
 593         rollback_lock_file(&index_lock);
 594 }
 595
 596 /*
 597  * Append a commit to the end of the commit_list.
 598  *
 599  * next starts by pointing to the variable that holds the head of an
 600  * empty commit_list, and is updated to point to the "next" field of
 601  * the last item on the list as new commits are appended.
 602  *
 603  * Usage example:
 604  *
 605  *     struct commit_list *list;
 606  *     struct commit_list **next = &list;
 607  *
 608  *     next = commit_list_append(c1, next);
 609  *     next = commit_list_append(c2, next);
 610  *     assert(commit_list_count(list) == 2);
 611  *     return list;
 612  */
 613 struct commit_list **commit_list_append(struct commit *commit,
 614                                         struct commit_list **next)
 615 {
 616         struct commit_list *new = xmalloc(sizeof(struct commit_list));
 617         new->item = commit;
 618         *next = new;
 619         new->next = NULL;
 620         return &new->next;
 621 }
 622
 623 static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
 624                 struct replay_opts *opts)
 625 {
 626         struct commit_list *cur = NULL;
 627         struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 628         const char *sha1_abbrev = NULL;
 629         const char *action_str = opts->action == REVERT ? "revert" : "pick";
 630
 631         for (cur = todo_list; cur; cur = cur->next) {
 632                 sha1_abbrev = find_unique_abbrev(cur->item->object.sha1, DEFAULT_ABBREV);
 633                 if (get_message(cur->item, &msg))
 634                         return error(_("Cannot get commit message for %s"), sha1_abbrev);
 635                 strbuf_addf(buf, "%s %s %s\n", action_str, sha1_abbrev, msg.subject);
 636         }
 637         return 0;
 638 }
 639
 640 static void walk_revs_populate_todo(struct commit_list **todo_list,
 641                                 struct replay_opts *opts)
 642 {
 643         struct rev_info revs;
 644         struct commit *commit;
 645         struct commit_list **next;
 646
 647         prepare_revs(&revs, opts);
 648
 649         next = todo_list;
 650         while ((commit = get_revision(&revs)))
 651                 next = commit_list_append(commit, next);
 652 }
 653
 654 static void create_seq_dir(void)
 655 {
 656         const char *seq_dir = git_path(SEQ_DIR);
 657
 658         if (!(file_exists(seq_dir) && is_directory(seq_dir))
 659                 && mkdir(seq_dir, 0777) < 0)
 660                 die_errno(_("Could not create sequencer directory '%s'."), seq_dir);
 661 }
 662
 663 static void save_head(const char *head)
 664 {
 665         const char *head_file = git_path(SEQ_HEAD_FILE);
 666         static struct lock_file head_lock;
 667         struct strbuf buf = STRBUF_INIT;
 668         int fd;
 669
 670         fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 671         strbuf_addf(&buf, "%s\n", head);
 672         if (write_in_full(fd, buf.buf, buf.len) < 0)
 673                 die_errno(_("Could not write to %s."), head_file);
 674         if (commit_lock_file(&head_lock) < 0)
 675                 die(_("Error wrapping up %s."), head_file);
 676 }
 677
 678 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 679 {
 680         const char *todo_file = git_path(SEQ_TODO_FILE);
 681         static struct lock_file todo_lock;
 682         struct strbuf buf = STRBUF_INIT;
 683         int fd;
 684
 685         fd = hold_lock_file_for_update(&todo_lock, todo_file, LOCK_DIE_ON_ERROR);
 686         if (format_todo(&buf, todo_list, opts) < 0)
 687                 die(_("Could not format %s."), todo_file);
 688         if (write_in_full(fd, buf.buf, buf.len) < 0) {
 689                 strbuf_release(&buf);
 690                 die_errno(_("Could not write to %s."), todo_file);
 691         }
 692         if (commit_lock_file(&todo_lock) < 0) {
 693                 strbuf_release(&buf);
 694                 die(_("Error wrapping up %s."), todo_file);
 695         }
 696         strbuf_release(&buf);
 697 }
 698
 699 static void save_opts(struct replay_opts *opts)
 700 {
 701         const char *opts_file = git_path(SEQ_OPTS_FILE);
 702
 703         if (opts->no_commit)
 704                 git_config_set_in_file(opts_file, "options.no-commit", "true");
 705         if (opts->edit)
 706                 git_config_set_in_file(opts_file, "options.edit", "true");
 707         if (opts->signoff)
 708                 git_config_set_in_file(opts_file, "options.signoff", "true");
 709         if (opts->record_origin)
 710                 git_config_set_in_file(opts_file, "options.record-origin", "true");
 711         if (opts->allow_ff)
 712                 git_config_set_in_file(opts_file, "options.allow-ff", "true");
 713         if (opts->mainline) {
 714                 struct strbuf buf = STRBUF_INIT;
 715                 strbuf_addf(&buf, "%d", opts->mainline);
 716                 git_config_set_in_file(opts_file, "options.mainline", buf.buf);
 717                 strbuf_release(&buf);
 718         }
 719         if (opts->strategy)
 720                 git_config_set_in_file(opts_file, "options.strategy", opts->strategy);
 721         if (opts->xopts) {
 722                 int i;
 723                 for (i = 0; i < opts->xopts_nr; i++)
 724                         git_config_set_multivar_in_file(opts_file,
 725                                                         "options.strategy-option",
 726                                                         opts->xopts[i], "^$", 0);
 727         }
 728 }
 729
 730 static int pick_commits(struct replay_opts *opts)
 731 {
 732         struct commit_list *todo_list = NULL;
 733         struct strbuf buf = STRBUF_INIT;
 734         unsigned char sha1[20];
 735         struct commit_list *cur;
 736         int res;
 737
 738         setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
 739         if (opts->allow_ff)
 740                 assert(!(opts->signoff || opts->no_commit ||
 741                                 opts->record_origin || opts->edit));
 742         read_and_refresh_cache(opts);
 743
 744         walk_revs_populate_todo(&todo_list, opts);
 745         create_seq_dir();
 746         if (get_sha1("HEAD", sha1)) {
 747                 if (opts->action == REVERT)
 748                         die(_("Can't revert as initial commit"));
 749                 die(_("Can't cherry-pick into empty head"));
 750         }
 751         save_head(sha1_to_hex(sha1));
 752         save_opts(opts);
 753
 754         for (cur = todo_list; cur; cur = cur->next) {
 755                 save_todo(cur, opts);
 756                 res = do_pick_commit(cur->item, opts);
 757                 if (res)
 758                         return res;
 759         }
 760
 761         /*
 762          * Sequence of picks finished successfully; cleanup by
 763          * removing the .git/sequencer directory
 764          */
 765         strbuf_addf(&buf, "%s", git_path(SEQ_DIR));
 766         remove_dir_recursively(&buf, 0);
 767         strbuf_release(&buf);
 768         return 0;
 769 }
 770
 771 int cmd_revert(int argc, const char **argv, const char *prefix)
 772 {
 773         struct replay_opts opts;
 774
 775         memset(&opts, 0, sizeof(opts));
 776         if (isatty(0))
 777                 opts.edit = 1;
 778         opts.action = REVERT;
 779         git_config(git_default_config, NULL);
 780         parse_args(argc, argv, &opts);
 781         return pick_commits(&opts);
 782 }
 783
 784 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 785 {
 786         struct replay_opts opts;
 787
 788         memset(&opts, 0, sizeof(opts));
 789         opts.action = CHERRY_PICK;
 790         git_config(git_default_config, NULL);
 791         parse_args(argc, argv, &opts);
 792         return pick_commits(&opts);
 793 }