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 || cb->cmd->verbose)
 334                 printf("%sprune %s", cb->newlog ? "" : "would ", message);
 335         return 0;
 336 }
 337
 338 static int push_tip_to_list(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
 339 {
 340         struct commit_list **list = cb_data;
 341         struct commit *tip_commit;
 342         if (flags & REF_ISSYMREF)
 343                 return 0;
 344         tip_commit = lookup_commit_reference_gently(sha1, 1);
 345         if (!tip_commit)
 346                 return 0;
 347         commit_list_insert(tip_commit, list);
 348         return 0;
 349 }
 350
 351 static int expire_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
 352 {
 353         struct cmd_reflog_expire_cb *cmd = cb_data;
 354         struct expire_reflog_cb cb;
 355         struct ref_lock *lock;
 356         char *log_file, *newlog_path = NULL;
 357         struct commit *tip_commit;
 358         struct commit_list *tips;
 359         int status = 0;
 360
 361         memset(&cb, 0, sizeof(cb));
 362
 363         /*
 364          * we take the lock for the ref itself to prevent it from
 365          * getting updated.
 366          */
 367         lock = lock_any_ref_for_update(ref, sha1, 0);
 368         if (!lock)
 369                 return error("cannot lock ref '%s'", ref);
 370         log_file = git_pathdup("logs/%s", ref);
 371         if (!file_exists(log_file))
 372                 goto finish;
 373         if (!cmd->dry_run) {
 374                 newlog_path = git_pathdup("logs/%s.lock", ref);
 375                 cb.newlog = fopen(newlog_path, "w");
 376         }
 377
 378         cb.cmd = cmd;
 379
 380         if (!cmd->expire_unreachable || !strcmp(ref, "HEAD")) {
 381                 tip_commit = NULL;
 382                 cb.unreachable_expire_kind = UE_HEAD;
 383         } else {
 384                 tip_commit = lookup_commit_reference_gently(sha1, 1);
 385                 if (!tip_commit)
 386                         cb.unreachable_expire_kind = UE_ALWAYS;
 387                 else
 388                         cb.unreachable_expire_kind = UE_NORMAL;
 389         }
 390
 391         if (cmd->expire_unreachable <= cmd->expire_total)
 392                 cb.unreachable_expire_kind = UE_ALWAYS;
 393
 394         cb.mark_list = NULL;
 395         tips = NULL;
 396         if (cb.unreachable_expire_kind != UE_ALWAYS) {
 397                 if (cb.unreachable_expire_kind == UE_HEAD) {
 398                         struct commit_list *elem;
 399                         for_each_ref(push_tip_to_list, &tips);
 400                         for (elem = tips; elem; elem = elem->next)
 401                                 commit_list_insert(elem->item, &cb.mark_list);
 402                 } else {
 403                         commit_list_insert(tip_commit, &cb.mark_list);
 404                 }
 405                 cb.mark_limit = cmd->expire_total;
 406                 mark_reachable(&cb);
 407         }
 408
 409         for_each_reflog_ent(ref, expire_reflog_ent, &cb);
 410
 411         if (cb.unreachable_expire_kind != UE_ALWAYS) {
 412                 if (cb.unreachable_expire_kind == UE_HEAD) {
 413                         struct commit_list *elem;
 414                         for (elem = tips; elem; elem = elem->next)
 415                                 clear_commit_marks(tip_commit, REACHABLE);
 416                         free_commit_list(tips);
 417                 } else {
 418                         clear_commit_marks(tip_commit, REACHABLE);
 419                 }
 420         }
 421  finish:
 422         if (cb.newlog) {
 423                 if (fclose(cb.newlog)) {
 424                         status |= error("%s: %s", strerror(errno),
 425                                         newlog_path);
 426                         unlink(newlog_path);
 427                 } else if (cmd->updateref &&
 428                         (write_in_full(lock->lock_fd,
 429                                 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
 430                          write_str_in_full(lock->lock_fd, "\n") != 1 ||
 431                          close_ref(lock) < 0)) {
 432                         status |= error("Couldn't write %s",
 433                                 lock->lk->filename);
 434                         unlink(newlog_path);
 435                 } else if (rename(newlog_path, log_file)) {
 436                         status |= error("cannot rename %s to %s",
 437                                         newlog_path, log_file);
 438                         unlink(newlog_path);
 439                 } else if (cmd->updateref && commit_ref(lock)) {
 440                         status |= error("Couldn't set %s", lock->ref_name);
 441                 } else {
 442                         adjust_shared_perm(log_file);
 443                 }
 444         }
 445         free(newlog_path);
 446         free(log_file);
 447         unlock_ref(lock);
 448         return status;
 449 }
 450
 451 static int collect_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
 452 {
 453         struct collected_reflog *e;
 454         struct collect_reflog_cb *cb = cb_data;
 455         size_t namelen = strlen(ref);
 456
 457         e = xmalloc(sizeof(*e) + namelen + 1);
 458         hashcpy(e->sha1, sha1);
 459         memcpy(e->reflog, ref, namelen + 1);
 460         ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
 461         cb->e[cb->nr++] = e;
 462         return 0;
 463 }
 464
 465 static struct reflog_expire_cfg {
 466         struct reflog_expire_cfg *next;
 467         unsigned long expire_total;
 468         unsigned long expire_unreachable;
 469         size_t len;
 470         char pattern[FLEX_ARRAY];
 471 } *reflog_expire_cfg, **reflog_expire_cfg_tail;
 472
 473 static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
 474 {
 475         struct reflog_expire_cfg *ent;
 476
 477         if (!reflog_expire_cfg_tail)
 478                 reflog_expire_cfg_tail = &reflog_expire_cfg;
 479
 480         for (ent = reflog_expire_cfg; ent; ent = ent->next)
 481                 if (ent->len == len &&
 482                     !memcmp(ent->pattern, pattern, len))
 483                         return ent;
 484
 485         ent = xcalloc(1, (sizeof(*ent) + len));
 486         memcpy(ent->pattern, pattern, len);
 487         ent->len = len;
 488         *reflog_expire_cfg_tail = ent;
 489         reflog_expire_cfg_tail = &(ent->next);
 490         return ent;
 491 }
 492
 493 static int parse_expire_cfg_value(const char *var, const char *value, unsigned long *expire)
 494 {
 495         if (!value)
 496                 return config_error_nonbool(var);
 497         if (!strcmp(value, "never") || !strcmp(value, "false")) {
 498                 *expire = 0;
 499                 return 0;
 500         }
 501         *expire = approxidate(value);
 502         return 0;
 503 }
 504
 505 /* expiry timer slot */
 506 #define EXPIRE_TOTAL   01
 507 #define EXPIRE_UNREACH 02
 508
 509 static int reflog_expire_config(const char *var, const char *value, void *cb)
 510 {
 511         const char *lastdot = strrchr(var, '.');
 512         unsigned long expire;
 513         int slot;
 514         struct reflog_expire_cfg *ent;
 515
 516         if (!lastdot || prefixcmp(var, "gc."))
 517                 return git_default_config(var, value, cb);
 518
 519         if (!strcmp(lastdot, ".reflogexpire")) {
 520                 slot = EXPIRE_TOTAL;
 521                 if (parse_expire_cfg_value(var, value, &expire))
 522                         return -1;
 523         } else if (!strcmp(lastdot, ".reflogexpireunreachable")) {
 524                 slot = EXPIRE_UNREACH;
 525                 if (parse_expire_cfg_value(var, value, &expire))
 526                         return -1;
 527         } else
 528                 return git_default_config(var, value, cb);
 529
 530         if (lastdot == var + 2) {
 531                 switch (slot) {
 532                 case EXPIRE_TOTAL:
 533                         default_reflog_expire = expire;
 534                         break;
 535                 case EXPIRE_UNREACH:
 536                         default_reflog_expire_unreachable = expire;
 537                         break;
 538                 }
 539                 return 0;
 540         }
 541
 542         ent = find_cfg_ent(var + 3, lastdot - (var+3));
 543         if (!ent)
 544                 return -1;
 545         switch (slot) {
 546         case EXPIRE_TOTAL:
 547                 ent->expire_total = expire;
 548                 break;
 549         case EXPIRE_UNREACH:
 550                 ent->expire_unreachable = expire;
 551                 break;
 552         }
 553         return 0;
 554 }
 555
 556 static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
 557 {
 558         struct reflog_expire_cfg *ent;
 559
 560         if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
 561                 return; /* both given explicitly -- nothing to tweak */
 562
 563         for (ent = reflog_expire_cfg; ent; ent = ent->next) {
 564                 if (!fnmatch(ent->pattern, ref, 0)) {
 565                         if (!(slot & EXPIRE_TOTAL))
 566                                 cb->expire_total = ent->expire_total;
 567                         if (!(slot & EXPIRE_UNREACH))
 568                                 cb->expire_unreachable = ent->expire_unreachable;
 569                         return;
 570                 }
 571         }
 572
 573         /*
 574          * If unconfigured, make stash never expire
 575          */
 576         if (!strcmp(ref, "refs/stash")) {
 577                 if (!(slot & EXPIRE_TOTAL))
 578                         cb->expire_total = 0;
 579                 if (!(slot & EXPIRE_UNREACH))
 580                         cb->expire_unreachable = 0;
 581                 return;
 582         }
 583
 584         /* Nothing matched -- use the default value */
 585         if (!(slot & EXPIRE_TOTAL))
 586                 cb->expire_total = default_reflog_expire;
 587         if (!(slot & EXPIRE_UNREACH))
 588                 cb->expire_unreachable = default_reflog_expire_unreachable;
 589 }
 590
 591 static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 592 {
 593         struct cmd_reflog_expire_cb cb;
 594         unsigned long now = time(NULL);
 595         int i, status, do_all;
 596         int explicit_expiry = 0;
 597
 598         default_reflog_expire_unreachable = now - 30 * 24 * 3600;
 599         default_reflog_expire = now - 90 * 24 * 3600;
 600         git_config(reflog_expire_config, NULL);
 601
 602         save_commit_buffer = 0;
 603         do_all = status = 0;
 604         memset(&cb, 0, sizeof(cb));
 605
 606         cb.expire_total = default_reflog_expire;
 607         cb.expire_unreachable = default_reflog_expire_unreachable;
 608
 609         for (i = 1; i < argc; i++) {
 610                 const char *arg = argv[i];
 611                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 612                         cb.dry_run = 1;
 613                 else if (!prefixcmp(arg, "--expire=")) {
 614                         cb.expire_total = approxidate(arg + 9);
 615                         explicit_expiry |= EXPIRE_TOTAL;
 616                 }
 617                 else if (!prefixcmp(arg, "--expire-unreachable=")) {
 618                         cb.expire_unreachable = approxidate(arg + 21);
 619                         explicit_expiry |= EXPIRE_UNREACH;
 620                 }
 621                 else if (!strcmp(arg, "--stale-fix"))
 622                         cb.stalefix = 1;
 623                 else if (!strcmp(arg, "--rewrite"))
 624                         cb.rewrite = 1;
 625                 else if (!strcmp(arg, "--updateref"))
 626                         cb.updateref = 1;
 627                 else if (!strcmp(arg, "--all"))
 628                         do_all = 1;
 629                 else if (!strcmp(arg, "--verbose"))
 630                         cb.verbose = 1;
 631                 else if (!strcmp(arg, "--")) {
 632                         i++;
 633                         break;
 634                 }
 635                 else if (arg[0] == '-')
 636                         usage(reflog_expire_usage);
 637                 else
 638                         break;
 639         }
 640
 641         /*
 642          * We can trust the commits and objects reachable from refs
 643          * even in older repository.  We cannot trust what's reachable
 644          * from reflog if the repository was pruned with older git.
 645          */
 646         if (cb.stalefix) {
 647                 init_revisions(&cb.revs, prefix);
 648                 if (cb.verbose)
 649                         printf("Marking reachable objects...");
 650                 mark_reachable_objects(&cb.revs, 0);
 651                 if (cb.verbose)
 652                         putchar('\n');
 653         }
 654
 655         if (do_all) {
 656                 struct collect_reflog_cb collected;
 657                 int i;
 658
 659                 memset(&collected, 0, sizeof(collected));
 660                 for_each_reflog(collect_reflog, &collected);
 661                 for (i = 0; i < collected.nr; i++) {
 662                         struct collected_reflog *e = collected.e[i];
 663                         set_reflog_expiry_param(&cb, explicit_expiry, e->reflog);
 664                         status |= expire_reflog(e->reflog, e->sha1, 0, &cb);
 665                         free(e);
 666                 }
 667                 free(collected.e);
 668         }
 669
 670         for (; i < argc; i++) {
 671                 char *ref;
 672                 unsigned char sha1[20];
 673                 if (!dwim_log(argv[i], strlen(argv[i]), sha1, &ref)) {
 674                         status |= error("%s points nowhere!", argv[i]);
 675                         continue;
 676                 }
 677                 set_reflog_expiry_param(&cb, explicit_expiry, ref);
 678                 status |= expire_reflog(ref, sha1, 0, &cb);
 679         }
 680         return status;
 681 }
 682
 683 static int count_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 684                 const char *email, unsigned long timestamp, int tz,
 685                 const char *message, void *cb_data)
 686 {
 687         struct cmd_reflog_expire_cb *cb = cb_data;
 688         if (!cb->expire_total || timestamp < cb->expire_total)
 689                 cb->recno++;
 690         return 0;
 691 }
 692
 693 static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
 694 {
 695         struct cmd_reflog_expire_cb cb;
 696         int i, status = 0;
 697
 698         memset(&cb, 0, sizeof(cb));
 699
 700         for (i = 1; i < argc; i++) {
 701                 const char *arg = argv[i];
 702                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 703                         cb.dry_run = 1;
 704                 else if (!strcmp(arg, "--rewrite"))
 705                         cb.rewrite = 1;
 706                 else if (!strcmp(arg, "--updateref"))
 707                         cb.updateref = 1;
 708                 else if (!strcmp(arg, "--verbose"))
 709                         cb.verbose = 1;
 710                 else if (!strcmp(arg, "--")) {
 711                         i++;
 712                         break;
 713                 }
 714                 else if (arg[0] == '-')
 715                         usage(reflog_delete_usage);
 716                 else
 717                         break;
 718         }
 719
 720         if (argc - i < 1)
 721                 return error("Nothing to delete?");
 722
 723         for ( ; i < argc; i++) {
 724                 const char *spec = strstr(argv[i], "@{");
 725                 unsigned char sha1[20];
 726                 char *ep, *ref;
 727                 int recno;
 728
 729                 if (!spec) {
 730                         status |= error("Not a reflog: %s", argv[i]);
 731                         continue;
 732                 }
 733
 734                 if (!dwim_log(argv[i], spec - argv[i], sha1, &ref)) {
 735                         status |= error("no reflog for '%s'", argv[i]);
 736                         continue;
 737                 }
 738
 739                 recno = strtoul(spec + 2, &ep, 10);
 740                 if (*ep == '}') {
 741                         cb.recno = -recno;
 742                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
 743                 } else {
 744                         cb.expire_total = approxidate(spec + 2);
 745                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
 746                         cb.expire_total = 0;
 747                 }
 748
 749                 status |= expire_reflog(ref, sha1, 0, &cb);
 750                 free(ref);
 751         }
 752         return status;
 753 }
 754
 755 /*
 756  * main "reflog"
 757  */
 758
 759 static const char reflog_usage[] =
 760 "git reflog [ show | expire | delete ]";
 761
 762 int cmd_reflog(int argc, const char **argv, const char *prefix)
 763 {
 764         if (argc > 1 && !strcmp(argv[1], "-h"))
 765                 usage(reflog_usage);
 766
 767         /* With no command, we default to showing it. */
 768         if (argc < 2 || *argv[1] == '-')
 769                 return cmd_log_reflog(argc, argv, prefix);
 770
 771         if (!strcmp(argv[1], "show"))
 772                 return cmd_log_reflog(argc - 1, argv + 1, prefix);
 773
 774         if (!strcmp(argv[1], "expire"))
 775                 return cmd_reflog_expire(argc - 1, argv + 1, prefix);
 776
 777         if (!strcmp(argv[1], "delete"))
 778                 return cmd_reflog_delete(argc - 1, argv + 1, prefix);
 779
 780         /* Not a recognized reflog command..*/
 781         usage(reflog_usage);
 782 }