builtin/reflog.c

   1 #include "cache.h"
   2 #include "builtin.h"
   3 #include "commit.h"
   4 #include "refs.h"
   5 #include "dir.h"
   6 #include "tree-walk.h"
   7 #include "diff.h"
   8 #include "revision.h"
   9 #include "reachable.h"
  10
  11 /*
  12  * reflog expire
  13  */
  14
  15 static const char reflog_expire_usage[] =
  16 "git reflog expire [--verbose] [--dry-run] [--stale-fix] [--expire=<time>] [--expire-unreachable=<time>] [--all] <refs>...";
  17 static const char reflog_delete_usage[] =
  18 "git reflog delete [--verbose] [--dry-run] [--rewrite] [--updateref] <refs>...";
  19
  20 static unsigned long default_reflog_expire;
  21 static unsigned long default_reflog_expire_unreachable;
  22
  23 struct cmd_reflog_expire_cb {
  24         struct rev_info revs;
  25         int dry_run;
  26         int stalefix;
  27         int rewrite;
  28         int updateref;
  29         int verbose;
  30         unsigned long expire_total;
  31         unsigned long expire_unreachable;
  32         int recno;
  33 };
  34
  35 struct expire_reflog_cb {
  36         FILE *newlog;
  37         enum {
  38                 UE_NORMAL,
  39                 UE_ALWAYS,
  40                 UE_HEAD
  41         } unreachable_expire_kind;
  42         struct commit_list *mark_list;
  43         unsigned long mark_limit;
  44         struct cmd_reflog_expire_cb *cmd;
  45         unsigned char last_kept_sha1[20];
  46 };
  47
  48 struct collected_reflog {
  49         unsigned char sha1[20];
  50         char reflog[FLEX_ARRAY];
  51 };
  52 struct collect_reflog_cb {
  53         struct collected_reflog **e;
  54         int alloc;
  55         int nr;
  56 };
  57
  58 #define INCOMPLETE      (1u<<10)
  59 #define STUDYING        (1u<<11)
  60 #define REACHABLE       (1u<<12)
  61
  62 static int tree_is_complete(const unsigned char *sha1)
  63 {
  64         struct tree_desc desc;
  65         struct name_entry entry;
  66         int complete;
  67         struct tree *tree;
  68
  69         tree = lookup_tree(sha1);
  70         if (!tree)
  71                 return 0;
  72         if (tree->object.flags & SEEN)
  73                 return 1;
  74         if (tree->object.flags & INCOMPLETE)
  75                 return 0;
  76
  77         if (!tree->buffer) {
  78                 enum object_type type;
  79                 unsigned long size;
  80                 void *data = read_sha1_file(sha1, &type, &size);
  81                 if (!data) {
  82                         tree->object.flags |= INCOMPLETE;
  83                         return 0;
  84                 }
  85                 tree->buffer = data;
  86                 tree->size = size;
  87         }
  88         init_tree_desc(&desc, tree->buffer, tree->size);
  89         complete = 1;
  90         while (tree_entry(&desc, &entry)) {
  91                 if (!has_sha1_file(entry.sha1) ||
  92                     (S_ISDIR(entry.mode) && !tree_is_complete(entry.sha1))) {
  93                         tree->object.flags |= INCOMPLETE;
  94                         complete = 0;
  95                 }
  96         }
  97         free(tree->buffer);
  98         tree->buffer = NULL;
  99
 100         if (complete)
 101                 tree->object.flags |= SEEN;
 102         return complete;
 103 }
 104
 105 static int commit_is_complete(struct commit *commit)
 106 {
 107         struct object_array study;
 108         struct object_array found;
 109         int is_incomplete = 0;
 110         int i;
 111
 112         /* early return */
 113         if (commit->object.flags & SEEN)
 114                 return 1;
 115         if (commit->object.flags & INCOMPLETE)
 116                 return 0;
 117         /*
 118          * Find all commits that are reachable and are not marked as
 119          * SEEN.  Then make sure the trees and blobs contained are
 120          * complete.  After that, mark these commits also as SEEN.
 121          * If some of the objects that are needed to complete this
 122          * commit are missing, mark this commit as INCOMPLETE.
 123          */
 124         memset(&study, 0, sizeof(study));
 125         memset(&found, 0, sizeof(found));
 126         add_object_array(&commit->object, NULL, &study);
 127         add_object_array(&commit->object, NULL, &found);
 128         commit->object.flags |= STUDYING;
 129         while (study.nr) {
 130                 struct commit *c;
 131                 struct commit_list *parent;
 132
 133                 c = (struct commit *)study.objects[--study.nr].item;
 134                 if (!c->object.parsed && !parse_object(c->object.sha1))
 135                         c->object.flags |= INCOMPLETE;
 136
 137                 if (c->object.flags & INCOMPLETE) {
 138                         is_incomplete = 1;
 139                         break;
 140                 }
 141                 else if (c->object.flags & SEEN)
 142                         continue;
 143                 for (parent = c->parents; parent; parent = parent->next) {
 144                         struct commit *p = parent->item;
 145                         if (p->object.flags & STUDYING)
 146                                 continue;
 147                         p->object.flags |= STUDYING;
 148                         add_object_array(&p->object, NULL, &study);
 149                         add_object_array(&p->object, NULL, &found);
 150                 }
 151         }
 152         if (!is_incomplete) {
 153                 /*
 154                  * make sure all commits in "found" array have all the
 155                  * necessary objects.
 156                  */
 157                 for (i = 0; i < found.nr; i++) {
 158                         struct commit *c =
 159                                 (struct commit *)found.objects[i].item;
 160                         if (!tree_is_complete(c->tree->object.sha1)) {
 161                                 is_incomplete = 1;
 162                                 c->object.flags |= INCOMPLETE;
 163                         }
 164                 }
 165                 if (!is_incomplete) {
 166                         /* mark all found commits as complete, iow SEEN */
 167                         for (i = 0; i < found.nr; i++)
 168                                 found.objects[i].item->flags |= SEEN;
 169                 }
 170         }
 171         /* clear flags from the objects we traversed */
 172         for (i = 0; i < found.nr; i++)
 173                 found.objects[i].item->flags &= ~STUDYING;
 174         if (is_incomplete)
 175                 commit->object.flags |= INCOMPLETE;
 176         else {
 177                 /*
 178                  * If we come here, we have (1) traversed the ancestry chain
 179                  * from the "commit" until we reach SEEN commits (which are
 180                  * known to be complete), and (2) made sure that the commits
 181                  * encountered during the above traversal refer to trees that
 182                  * are complete.  Which means that we know *all* the commits
 183                  * we have seen during this process are complete.
 184                  */
 185                 for (i = 0; i < found.nr; i++)
 186                         found.objects[i].item->flags |= SEEN;
 187         }
 188         /* free object arrays */
 189         free(study.objects);
 190         free(found.objects);
 191         return !is_incomplete;
 192 }
 193
 194 static int keep_entry(struct commit **it, unsigned char *sha1)
 195 {
 196         struct commit *commit;
 197
 198         if (is_null_sha1(sha1))
 199                 return 1;
 200         commit = lookup_commit_reference_gently(sha1, 1);
 201         if (!commit)
 202                 return 0;
 203
 204         /*
 205          * Make sure everything in this commit exists.
 206          *
 207          * We have walked all the objects reachable from the refs
 208          * and cache earlier.  The commits reachable by this commit
 209          * must meet SEEN commits -- and then we should mark them as
 210          * SEEN as well.
 211          */
 212         if (!commit_is_complete(commit))
 213                 return 0;
 214         *it = commit;
 215         return 1;
 216 }
 217
 218 /*
 219  * Starting from commits in the cb->mark_list, mark commits that are
 220  * reachable from them.  Stop the traversal at commits older than
 221  * the expire_limit and queue them back, so that the caller can call
 222  * us again to restart the traversal with longer expire_limit.
 223  */
 224 static void mark_reachable(struct expire_reflog_cb *cb)
 225 {
 226         struct commit *commit;
 227         struct commit_list *pending;
 228         unsigned long expire_limit = cb->mark_limit;
 229         struct commit_list *leftover = NULL;
 230
 231         for (pending = cb->mark_list; pending; pending = pending->next)
 232                 pending->item->object.flags &= ~REACHABLE;
 233
 234         pending = cb->mark_list;
 235         while (pending) {
 236                 struct commit_list *entry = pending;
 237                 struct commit_list *parent;
 238                 pending = entry->next;
 239                 commit = entry->item;
 240                 free(entry);
 241                 if (commit->object.flags & REACHABLE)
 242                         continue;
 243                 if (parse_commit(commit))
 244                         continue;
 245                 commit->object.flags |= REACHABLE;
 246                 if (commit->date < expire_limit) {
 247                         commit_list_insert(commit, &leftover);
 248                         continue;
 249                 }
 250                 commit->object.flags |= REACHABLE;
 251                 parent = commit->parents;
 252                 while (parent) {
 253                         commit = parent->item;
 254                         parent = parent->next;
 255                         if (commit->object.flags & REACHABLE)
 256                                 continue;
 257                         commit_list_insert(commit, &pending);
 258                 }
 259         }
 260         cb->mark_list = leftover;
 261 }
 262
 263 static int unreachable(struct expire_reflog_cb *cb, struct commit *commit, unsigned char *sha1)
 264 {
 265         /*
 266          * We may or may not have the commit yet - if not, look it
 267          * up using the supplied sha1.
 268          */
 269         if (!commit) {
 270                 if (is_null_sha1(sha1))
 271                         return 0;
 272
 273                 commit = lookup_commit_reference_gently(sha1, 1);
 274
 275                 /* Not a commit -- keep it */
 276                 if (!commit)
 277                         return 0;
 278         }
 279
 280         /* Reachable from the current ref?  Don't prune. */
 281         if (commit->object.flags & REACHABLE)
 282                 return 0;
 283
 284         if (cb->mark_list && cb->mark_limit) {
 285                 cb->mark_limit = 0; /* dig down to the root */
 286                 mark_reachable(cb);
 287         }
 288
 289         return !(commit->object.flags & REACHABLE);
 290 }
 291
 292 static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 293                 const char *email, unsigned long timestamp, int tz,
 294                 const char *message, void *cb_data)
 295 {
 296         struct expire_reflog_cb *cb = cb_data;
 297         struct commit *old, *new;
 298
 299         if (timestamp < cb->cmd->expire_total)
 300                 goto prune;
 301
 302         if (cb->cmd->rewrite)
 303                 osha1 = cb->last_kept_sha1;
 304
 305         old = new = NULL;
 306         if (cb->cmd->stalefix &&
 307             (!keep_entry(&old, osha1) || !keep_entry(&new, nsha1)))
 308                 goto prune;
 309
 310         if (timestamp < cb->cmd->expire_unreachable) {
 311                 if (cb->unreachable_expire_kind == UE_ALWAYS)
 312                         goto prune;
 313                 if (unreachable(cb, old, osha1) || unreachable(cb, new, nsha1))
 314                         goto prune;
 315         }
 316
 317         if (cb->cmd->recno && --(cb->cmd->recno) == 0)
 318                 goto prune;
 319
 320         if (cb->newlog) {
 321                 char sign = (tz < 0) ? '-' : '+';
 322                 int zone = (tz < 0) ? (-tz) : tz;
 323                 fprintf(cb->newlog, "%s %s %s %lu %c%04d\t%s",
 324                         sha1_to_hex(osha1), sha1_to_hex(nsha1),
 325                         email, timestamp, sign, zone,
 326                         message);
 327                 hashcpy(cb->last_kept_sha1, nsha1);
 328         }
 329         if (cb->cmd->verbose)
 330                 printf("keep %s", message);
 331         return 0;
 332  prune:
 333         if (!cb->newlog)
 334                 printf("would prune %s", message);
 335         else if (cb->cmd->verbose)
 336                 printf("prune %s", message);
 337         return 0;
 338 }
 339
 340 static int push_tip_to_list(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
 341 {
 342         struct commit_list **list = cb_data;
 343         struct commit *tip_commit;
 344         if (flags & REF_ISSYMREF)
 345                 return 0;
 346         tip_commit = lookup_commit_reference_gently(sha1, 1);
 347         if (!tip_commit)
 348                 return 0;
 349         commit_list_insert(tip_commit, list);
 350         return 0;
 351 }
 352
 353 static int expire_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
 354 {
 355         struct cmd_reflog_expire_cb *cmd = cb_data;
 356         struct expire_reflog_cb cb;
 357         struct ref_lock *lock;
 358         char *log_file, *newlog_path = NULL;
 359         struct commit *tip_commit;
 360         struct commit_list *tips;
 361         int status = 0;
 362
 363         memset(&cb, 0, sizeof(cb));
 364
 365         /*
 366          * we take the lock for the ref itself to prevent it from
 367          * getting updated.
 368          */
 369         lock = lock_any_ref_for_update(ref, sha1, 0);
 370         if (!lock)
 371                 return error("cannot lock ref '%s'", ref);
 372         log_file = git_pathdup("logs/%s", ref);
 373         if (!file_exists(log_file))
 374                 goto finish;
 375         if (!cmd->dry_run) {
 376                 newlog_path = git_pathdup("logs/%s.lock", ref);
 377                 cb.newlog = fopen(newlog_path, "w");
 378         }
 379
 380         cb.cmd = cmd;
 381
 382         if (!cmd->expire_unreachable || !strcmp(ref, "HEAD")) {
 383                 tip_commit = NULL;
 384                 cb.unreachable_expire_kind = UE_HEAD;
 385         } else {
 386                 tip_commit = lookup_commit_reference_gently(sha1, 1);
 387                 if (!tip_commit)
 388                         cb.unreachable_expire_kind = UE_ALWAYS;
 389                 else
 390                         cb.unreachable_expire_kind = UE_NORMAL;
 391         }
 392
 393         if (cmd->expire_unreachable <= cmd->expire_total)
 394                 cb.unreachable_expire_kind = UE_ALWAYS;
 395
 396         cb.mark_list = NULL;
 397         tips = NULL;
 398         if (cb.unreachable_expire_kind != UE_ALWAYS) {
 399                 if (cb.unreachable_expire_kind == UE_HEAD) {
 400                         struct commit_list *elem;
 401                         for_each_ref(push_tip_to_list, &tips);
 402                         for (elem = tips; elem; elem = elem->next)
 403                                 commit_list_insert(elem->item, &cb.mark_list);
 404                 } else {
 405                         commit_list_insert(tip_commit, &cb.mark_list);
 406                 }
 407                 cb.mark_limit = cmd->expire_total;
 408                 mark_reachable(&cb);
 409         }
 410
 411         for_each_reflog_ent(ref, expire_reflog_ent, &cb);
 412
 413         if (cb.unreachable_expire_kind != UE_ALWAYS) {
 414                 if (cb.unreachable_expire_kind == UE_HEAD) {
 415                         struct commit_list *elem;
 416                         for (elem = tips; elem; elem = elem->next)
 417                                 clear_commit_marks(tip_commit, REACHABLE);
 418                         free_commit_list(tips);
 419                 } else {
 420                         clear_commit_marks(tip_commit, REACHABLE);
 421                 }
 422         }
 423  finish:
 424         if (cb.newlog) {
 425                 if (fclose(cb.newlog)) {
 426                         status |= error("%s: %s", strerror(errno),
 427                                         newlog_path);
 428                         unlink(newlog_path);
 429                 } else if (cmd->updateref &&
 430                         (write_in_full(lock->lock_fd,
 431                                 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
 432                          write_str_in_full(lock->lock_fd, "\n") != 1 ||
 433                          close_ref(lock) < 0)) {
 434                         status |= error("Couldn't write %s",
 435                                 lock->lk->filename);
 436                         unlink(newlog_path);
 437                 } else if (rename(newlog_path, log_file)) {
 438                         status |= error("cannot rename %s to %s",
 439                                         newlog_path, log_file);
 440                         unlink(newlog_path);
 441                 } else if (cmd->updateref && commit_ref(lock)) {
 442                         status |= error("Couldn't set %s", lock->ref_name);
 443                 } else {
 444                         adjust_shared_perm(log_file);
 445                 }
 446         }
 447         free(newlog_path);
 448         free(log_file);
 449         unlock_ref(lock);
 450         return status;
 451 }
 452
 453 static int collect_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
 454 {
 455         struct collected_reflog *e;
 456         struct collect_reflog_cb *cb = cb_data;
 457         size_t namelen = strlen(ref);
 458
 459         e = xmalloc(sizeof(*e) + namelen + 1);
 460         hashcpy(e->sha1, sha1);
 461         memcpy(e->reflog, ref, namelen + 1);
 462         ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
 463         cb->e[cb->nr++] = e;
 464         return 0;
 465 }
 466
 467 static struct reflog_expire_cfg {
 468         struct reflog_expire_cfg *next;
 469         unsigned long expire_total;
 470         unsigned long expire_unreachable;
 471         size_t len;
 472         char pattern[FLEX_ARRAY];
 473 } *reflog_expire_cfg, **reflog_expire_cfg_tail;
 474
 475 static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
 476 {
 477         struct reflog_expire_cfg *ent;
 478
 479         if (!reflog_expire_cfg_tail)
 480                 reflog_expire_cfg_tail = &reflog_expire_cfg;
 481
 482         for (ent = reflog_expire_cfg; ent; ent = ent->next)
 483                 if (ent->len == len &&
 484                     !memcmp(ent->pattern, pattern, len))
 485                         return ent;
 486
 487         ent = xcalloc(1, (sizeof(*ent) + len));
 488         memcpy(ent->pattern, pattern, len);
 489         ent->len = len;
 490         *reflog_expire_cfg_tail = ent;
 491         reflog_expire_cfg_tail = &(ent->next);
 492         return ent;
 493 }
 494
 495 static int parse_expire_cfg_value(const char *var, const char *value, unsigned long *expire)
 496 {
 497         if (!value)
 498                 return config_error_nonbool(var);
 499         if (!strcmp(value, "never") || !strcmp(value, "false")) {
 500                 *expire = 0;
 501                 return 0;
 502         }
 503         *expire = approxidate(value);
 504         return 0;
 505 }
 506
 507 /* expiry timer slot */
 508 #define EXPIRE_TOTAL   01
 509 #define EXPIRE_UNREACH 02
 510
 511 static int reflog_expire_config(const char *var, const char *value, void *cb)
 512 {
 513         const char *pattern, *key;
 514         int pattern_len;
 515         unsigned long expire;
 516         int slot;
 517         struct reflog_expire_cfg *ent;
 518
 519         if (parse_config_key(var, "gc", &pattern, &pattern_len, &key) < 0)
 520                 return git_default_config(var, value, cb);
 521
 522         if (!strcmp(key, "reflogexpire")) {
 523                 slot = EXPIRE_TOTAL;
 524                 if (parse_expire_cfg_value(var, value, &expire))
 525                         return -1;
 526         } else if (!strcmp(key, "reflogexpireunreachable")) {
 527                 slot = EXPIRE_UNREACH;
 528                 if (parse_expire_cfg_value(var, value, &expire))
 529                         return -1;
 530         } else
 531                 return git_default_config(var, value, cb);
 532
 533         if (!pattern) {
 534                 switch (slot) {
 535                 case EXPIRE_TOTAL:
 536                         default_reflog_expire = expire;
 537                         break;
 538                 case EXPIRE_UNREACH:
 539                         default_reflog_expire_unreachable = expire;
 540                         break;
 541                 }
 542                 return 0;
 543         }
 544
 545         ent = find_cfg_ent(pattern, pattern_len);
 546         if (!ent)
 547                 return -1;
 548         switch (slot) {
 549         case EXPIRE_TOTAL:
 550                 ent->expire_total = expire;
 551                 break;
 552         case EXPIRE_UNREACH:
 553                 ent->expire_unreachable = expire;
 554                 break;
 555         }
 556         return 0;
 557 }
 558
 559 static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
 560 {
 561         struct reflog_expire_cfg *ent;
 562
 563         if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
 564                 return; /* both given explicitly -- nothing to tweak */
 565
 566         for (ent = reflog_expire_cfg; ent; ent = ent->next) {
 567                 if (!fnmatch(ent->pattern, ref, 0)) {
 568                         if (!(slot & EXPIRE_TOTAL))
 569                                 cb->expire_total = ent->expire_total;
 570                         if (!(slot & EXPIRE_UNREACH))
 571                                 cb->expire_unreachable = ent->expire_unreachable;
 572                         return;
 573                 }
 574         }
 575
 576         /*
 577          * If unconfigured, make stash never expire
 578          */
 579         if (!strcmp(ref, "refs/stash")) {
 580                 if (!(slot & EXPIRE_TOTAL))
 581                         cb->expire_total = 0;
 582                 if (!(slot & EXPIRE_UNREACH))
 583                         cb->expire_unreachable = 0;
 584                 return;
 585         }
 586
 587         /* Nothing matched -- use the default value */
 588         if (!(slot & EXPIRE_TOTAL))
 589                 cb->expire_total = default_reflog_expire;
 590         if (!(slot & EXPIRE_UNREACH))
 591                 cb->expire_unreachable = default_reflog_expire_unreachable;
 592 }
 593
 594 static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 595 {
 596         struct cmd_reflog_expire_cb cb;
 597         unsigned long now = time(NULL);
 598         int i, status, do_all;
 599         int explicit_expiry = 0;
 600
 601         default_reflog_expire_unreachable = now - 30 * 24 * 3600;
 602         default_reflog_expire = now - 90 * 24 * 3600;
 603         git_config(reflog_expire_config, NULL);
 604
 605         save_commit_buffer = 0;
 606         do_all = status = 0;
 607         memset(&cb, 0, sizeof(cb));
 608
 609         cb.expire_total = default_reflog_expire;
 610         cb.expire_unreachable = default_reflog_expire_unreachable;
 611
 612         for (i = 1; i < argc; i++) {
 613                 const char *arg = argv[i];
 614                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 615                         cb.dry_run = 1;
 616                 else if (!prefixcmp(arg, "--expire=")) {
 617                         cb.expire_total = approxidate(arg + 9);
 618                         explicit_expiry |= EXPIRE_TOTAL;
 619                 }
 620                 else if (!prefixcmp(arg, "--expire-unreachable=")) {
 621                         cb.expire_unreachable = approxidate(arg + 21);
 622                         explicit_expiry |= EXPIRE_UNREACH;
 623                 }
 624                 else if (!strcmp(arg, "--stale-fix"))
 625                         cb.stalefix = 1;
 626                 else if (!strcmp(arg, "--rewrite"))
 627                         cb.rewrite = 1;
 628                 else if (!strcmp(arg, "--updateref"))
 629                         cb.updateref = 1;
 630                 else if (!strcmp(arg, "--all"))
 631                         do_all = 1;
 632                 else if (!strcmp(arg, "--verbose"))
 633                         cb.verbose = 1;
 634                 else if (!strcmp(arg, "--")) {
 635                         i++;
 636                         break;
 637                 }
 638                 else if (arg[0] == '-')
 639                         usage(reflog_expire_usage);
 640                 else
 641                         break;
 642         }
 643
 644         /*
 645          * We can trust the commits and objects reachable from refs
 646          * even in older repository.  We cannot trust what's reachable
 647          * from reflog if the repository was pruned with older git.
 648          */
 649         if (cb.stalefix) {
 650                 init_revisions(&cb.revs, prefix);
 651                 if (cb.verbose)
 652                         printf("Marking reachable objects...");
 653                 mark_reachable_objects(&cb.revs, 0, NULL);
 654                 if (cb.verbose)
 655                         putchar('\n');
 656         }
 657
 658         if (do_all) {
 659                 struct collect_reflog_cb collected;
 660                 int i;
 661
 662                 memset(&collected, 0, sizeof(collected));
 663                 for_each_reflog(collect_reflog, &collected);
 664                 for (i = 0; i < collected.nr; i++) {
 665                         struct collected_reflog *e = collected.e[i];
 666                         set_reflog_expiry_param(&cb, explicit_expiry, e->reflog);
 667                         status |= expire_reflog(e->reflog, e->sha1, 0, &cb);
 668                         free(e);
 669                 }
 670                 free(collected.e);
 671         }
 672
 673         for (; i < argc; i++) {
 674                 char *ref;
 675                 unsigned char sha1[20];
 676                 if (!dwim_log(argv[i], strlen(argv[i]), sha1, &ref)) {
 677                         status |= error("%s points nowhere!", argv[i]);
 678                         continue;
 679                 }
 680                 set_reflog_expiry_param(&cb, explicit_expiry, ref);
 681                 status |= expire_reflog(ref, sha1, 0, &cb);
 682         }
 683         return status;
 684 }
 685
 686 static int count_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 687                 const char *email, unsigned long timestamp, int tz,
 688                 const char *message, void *cb_data)
 689 {
 690         struct cmd_reflog_expire_cb *cb = cb_data;
 691         if (!cb->expire_total || timestamp < cb->expire_total)
 692                 cb->recno++;
 693         return 0;
 694 }
 695
 696 static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
 697 {
 698         struct cmd_reflog_expire_cb cb;
 699         int i, status = 0;
 700
 701         memset(&cb, 0, sizeof(cb));
 702
 703         for (i = 1; i < argc; i++) {
 704                 const char *arg = argv[i];
 705                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 706                         cb.dry_run = 1;
 707                 else if (!strcmp(arg, "--rewrite"))
 708                         cb.rewrite = 1;
 709                 else if (!strcmp(arg, "--updateref"))
 710                         cb.updateref = 1;
 711                 else if (!strcmp(arg, "--verbose"))
 712                         cb.verbose = 1;
 713                 else if (!strcmp(arg, "--")) {
 714                         i++;
 715                         break;
 716                 }
 717                 else if (arg[0] == '-')
 718                         usage(reflog_delete_usage);
 719                 else
 720                         break;
 721         }
 722
 723         if (argc - i < 1)
 724                 return error("Nothing to delete?");
 725
 726         for ( ; i < argc; i++) {
 727                 const char *spec = strstr(argv[i], "@{");
 728                 unsigned char sha1[20];
 729                 char *ep, *ref;
 730                 int recno;
 731
 732                 if (!spec) {
 733                         status |= error("Not a reflog: %s", argv[i]);
 734                         continue;
 735                 }
 736
 737                 if (!dwim_log(argv[i], spec - argv[i], sha1, &ref)) {
 738                         status |= error("no reflog for '%s'", argv[i]);
 739                         continue;
 740                 }
 741
 742                 recno = strtoul(spec + 2, &ep, 10);
 743                 if (*ep == '}') {
 744                         cb.recno = -recno;
 745                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
 746                 } else {
 747                         cb.expire_total = approxidate(spec + 2);
 748                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
 749                         cb.expire_total = 0;
 750                 }
 751
 752                 status |= expire_reflog(ref, sha1, 0, &cb);
 753                 free(ref);
 754         }
 755         return status;
 756 }
 757
 758 /*
 759  * main "reflog"
 760  */
 761
 762 static const char reflog_usage[] =
 763 "git reflog [ show | expire | delete ]";
 764
 765 int cmd_reflog(int argc, const char **argv, const char *prefix)
 766 {
 767         if (argc > 1 && !strcmp(argv[1], "-h"))
 768                 usage(reflog_usage);
 769
 770         /* With no command, we default to showing it. */
 771         if (argc < 2 || *argv[1] == '-')
 772                 return cmd_log_reflog(argc, argv, prefix);
 773
 774         if (!strcmp(argv[1], "show"))
 775                 return cmd_log_reflog(argc - 1, argv + 1, prefix);
 776
 777         if (!strcmp(argv[1], "expire"))
 778                 return cmd_reflog_expire(argc - 1, argv + 1, prefix);
 779
 780         if (!strcmp(argv[1], "delete"))
 781                 return cmd_reflog_delete(argc - 1, argv + 1, prefix);
 782
 783         return cmd_log_reflog(argc, argv, prefix);
 784 }