builtin/reflog.c

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