git.oblomov.eu Git - git/blob - 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 /*
  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 enum expire_reflog_flags {
  24         EXPIRE_REFLOGS_DRY_RUN = 1 << 0,
  25         EXPIRE_REFLOGS_UPDATE_REF = 1 << 1
  26 };
  27
  28 struct cmd_reflog_expire_cb {
  29         struct rev_info revs;
  30         int stalefix;
  31         int rewrite;
  32         int verbose;
  33         unsigned long expire_total;
  34         unsigned long expire_unreachable;
  35         int recno;
  36 };
  37
  38 struct expire_reflog_cb {
  39         FILE *newlog;
  40         enum {
  41                 UE_NORMAL,
  42                 UE_ALWAYS,
  43                 UE_HEAD
  44         } unreachable_expire_kind;
  45         struct commit_list *mark_list;
  46         unsigned long mark_limit;
  47         struct cmd_reflog_expire_cb *cmd;
  48         unsigned char last_kept_sha1[20];
  49         struct commit *tip_commit;
  50         struct commit_list *tips;
  51 };
  52
  53 struct collected_reflog {
  54         unsigned char sha1[20];
  55         char reflog[FLEX_ARRAY];
  56 };
  57 struct collect_reflog_cb {
  58         struct collected_reflog **e;
  59         int alloc;
  60         int nr;
  61 };
  62
  63 #define INCOMPLETE      (1u<<10)
  64 #define STUDYING        (1u<<11)
  65 #define REACHABLE       (1u<<12)
  66
  67 static int tree_is_complete(const unsigned char *sha1)
  68 {
  69         struct tree_desc desc;
  70         struct name_entry entry;
  71         int complete;
  72         struct tree *tree;
  73
  74         tree = lookup_tree(sha1);
  75         if (!tree)
  76                 return 0;
  77         if (tree->object.flags & SEEN)
  78                 return 1;
  79         if (tree->object.flags & INCOMPLETE)
  80                 return 0;
  81
  82         if (!tree->buffer) {
  83                 enum object_type type;
  84                 unsigned long size;
  85                 void *data = read_sha1_file(sha1, &type, &size);
  86                 if (!data) {
  87                         tree->object.flags |= INCOMPLETE;
  88                         return 0;
  89                 }
  90                 tree->buffer = data;
  91                 tree->size = size;
  92         }
  93         init_tree_desc(&desc, tree->buffer, tree->size);
  94         complete = 1;
  95         while (tree_entry(&desc, &entry)) {
  96                 if (!has_sha1_file(entry.sha1) ||
  97                     (S_ISDIR(entry.mode) && !tree_is_complete(entry.sha1))) {
  98                         tree->object.flags |= INCOMPLETE;
  99                         complete = 0;
 100                 }
 101         }
 102         free_tree_buffer(tree);
 103
 104         if (complete)
 105                 tree->object.flags |= SEEN;
 106         return complete;
 107 }
 108
 109 static int commit_is_complete(struct commit *commit)
 110 {
 111         struct object_array study;
 112         struct object_array found;
 113         int is_incomplete = 0;
 114         int i;
 115
 116         /* early return */
 117         if (commit->object.flags & SEEN)
 118                 return 1;
 119         if (commit->object.flags & INCOMPLETE)
 120                 return 0;
 121         /*
 122          * Find all commits that are reachable and are not marked as
 123          * SEEN.  Then make sure the trees and blobs contained are
 124          * complete.  After that, mark these commits also as SEEN.
 125          * If some of the objects that are needed to complete this
 126          * commit are missing, mark this commit as INCOMPLETE.
 127          */
 128         memset(&study, 0, sizeof(study));
 129         memset(&found, 0, sizeof(found));
 130         add_object_array(&commit->object, NULL, &study);
 131         add_object_array(&commit->object, NULL, &found);
 132         commit->object.flags |= STUDYING;
 133         while (study.nr) {
 134                 struct commit *c;
 135                 struct commit_list *parent;
 136
 137                 c = (struct commit *)study.objects[--study.nr].item;
 138                 if (!c->object.parsed && !parse_object(c->object.sha1))
 139                         c->object.flags |= INCOMPLETE;
 140
 141                 if (c->object.flags & INCOMPLETE) {
 142                         is_incomplete = 1;
 143                         break;
 144                 }
 145                 else if (c->object.flags & SEEN)
 146                         continue;
 147                 for (parent = c->parents; parent; parent = parent->next) {
 148                         struct commit *p = parent->item;
 149                         if (p->object.flags & STUDYING)
 150                                 continue;
 151                         p->object.flags |= STUDYING;
 152                         add_object_array(&p->object, NULL, &study);
 153                         add_object_array(&p->object, NULL, &found);
 154                 }
 155         }
 156         if (!is_incomplete) {
 157                 /*
 158                  * make sure all commits in "found" array have all the
 159                  * necessary objects.
 160                  */
 161                 for (i = 0; i < found.nr; i++) {
 162                         struct commit *c =
 163                                 (struct commit *)found.objects[i].item;
 164                         if (!tree_is_complete(c->tree->object.sha1)) {
 165                                 is_incomplete = 1;
 166                                 c->object.flags |= INCOMPLETE;
 167                         }
 168                 }
 169                 if (!is_incomplete) {
 170                         /* mark all found commits as complete, iow SEEN */
 171                         for (i = 0; i < found.nr; i++)
 172                                 found.objects[i].item->flags |= SEEN;
 173                 }
 174         }
 175         /* clear flags from the objects we traversed */
 176         for (i = 0; i < found.nr; i++)
 177                 found.objects[i].item->flags &= ~STUDYING;
 178         if (is_incomplete)
 179                 commit->object.flags |= INCOMPLETE;
 180         else {
 181                 /*
 182                  * If we come here, we have (1) traversed the ancestry chain
 183                  * from the "commit" until we reach SEEN commits (which are
 184                  * known to be complete), and (2) made sure that the commits
 185                  * encountered during the above traversal refer to trees that
 186                  * are complete.  Which means that we know *all* the commits
 187                  * we have seen during this process are complete.
 188                  */
 189                 for (i = 0; i < found.nr; i++)
 190                         found.objects[i].item->flags |= SEEN;
 191         }
 192         /* free object arrays */
 193         free(study.objects);
 194         free(found.objects);
 195         return !is_incomplete;
 196 }
 197
 198 static int keep_entry(struct commit **it, unsigned char *sha1)
 199 {
 200         struct commit *commit;
 201
 202         if (is_null_sha1(sha1))
 203                 return 1;
 204         commit = lookup_commit_reference_gently(sha1, 1);
 205         if (!commit)
 206                 return 0;
 207
 208         /*
 209          * Make sure everything in this commit exists.
 210          *
 211          * We have walked all the objects reachable from the refs
 212          * and cache earlier.  The commits reachable by this commit
 213          * must meet SEEN commits -- and then we should mark them as
 214          * SEEN as well.
 215          */
 216         if (!commit_is_complete(commit))
 217                 return 0;
 218         *it = commit;
 219         return 1;
 220 }
 221
 222 /*
 223  * Starting from commits in the cb->mark_list, mark commits that are
 224  * reachable from them.  Stop the traversal at commits older than
 225  * the expire_limit and queue them back, so that the caller can call
 226  * us again to restart the traversal with longer expire_limit.
 227  */
 228 static void mark_reachable(struct expire_reflog_cb *cb)
 229 {
 230         struct commit *commit;
 231         struct commit_list *pending;
 232         unsigned long expire_limit = cb->mark_limit;
 233         struct commit_list *leftover = NULL;
 234
 235         for (pending = cb->mark_list; pending; pending = pending->next)
 236                 pending->item->object.flags &= ~REACHABLE;
 237
 238         pending = cb->mark_list;
 239         while (pending) {
 240                 struct commit_list *entry = pending;
 241                 struct commit_list *parent;
 242                 pending = entry->next;
 243                 commit = entry->item;
 244                 free(entry);
 245                 if (commit->object.flags & REACHABLE)
 246                         continue;
 247                 if (parse_commit(commit))
 248                         continue;
 249                 commit->object.flags |= REACHABLE;
 250                 if (commit->date < expire_limit) {
 251                         commit_list_insert(commit, &leftover);
 252                         continue;
 253                 }
 254                 commit->object.flags |= REACHABLE;
 255                 parent = commit->parents;
 256                 while (parent) {
 257                         commit = parent->item;
 258                         parent = parent->next;
 259                         if (commit->object.flags & REACHABLE)
 260                                 continue;
 261                         commit_list_insert(commit, &pending);
 262                 }
 263         }
 264         cb->mark_list = leftover;
 265 }
 266
 267 static int unreachable(struct expire_reflog_cb *cb, struct commit *commit, unsigned char *sha1)
 268 {
 269         /*
 270          * We may or may not have the commit yet - if not, look it
 271          * up using the supplied sha1.
 272          */
 273         if (!commit) {
 274                 if (is_null_sha1(sha1))
 275                         return 0;
 276
 277                 commit = lookup_commit_reference_gently(sha1, 1);
 278
 279                 /* Not a commit -- keep it */
 280                 if (!commit)
 281                         return 0;
 282         }
 283
 284         /* Reachable from the current ref?  Don't prune. */
 285         if (commit->object.flags & REACHABLE)
 286                 return 0;
 287
 288         if (cb->mark_list && cb->mark_limit) {
 289                 cb->mark_limit = 0; /* dig down to the root */
 290                 mark_reachable(cb);
 291         }
 292
 293         return !(commit->object.flags & REACHABLE);
 294 }
 295
 296 /*
 297  * Return true iff the specified reflog entry should be expired.
 298  */
 299 static int should_expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 300                                     const char *email, unsigned long timestamp, int tz,
 301                                     const char *message, void *cb_data)
 302 {
 303         struct expire_reflog_cb *cb = cb_data;
 304         struct commit *old, *new;
 305
 306         if (timestamp < cb->cmd->expire_total)
 307                 return 1;
 308
 309         old = new = NULL;
 310         if (cb->cmd->stalefix &&
 311             (!keep_entry(&old, osha1) || !keep_entry(&new, nsha1)))
 312                 return 1;
 313
 314         if (timestamp < cb->cmd->expire_unreachable) {
 315                 if (cb->unreachable_expire_kind == UE_ALWAYS)
 316                         return 1;
 317                 if (unreachable(cb, old, osha1) || unreachable(cb, new, nsha1))
 318                         return 1;
 319         }
 320
 321         if (cb->cmd->recno && --(cb->cmd->recno) == 0)
 322                 return 1;
 323
 324         return 0;
 325 }
 326
 327 static int expire_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 328                 const char *email, unsigned long timestamp, int tz,
 329                 const char *message, void *cb_data)
 330 {
 331         struct expire_reflog_cb *cb = cb_data;
 332
 333         if (cb->cmd->rewrite)
 334                 osha1 = cb->last_kept_sha1;
 335
 336         if (should_expire_reflog_ent(osha1, nsha1, email, timestamp, tz,
 337                                      message, cb_data)) {
 338                 if (!cb->newlog)
 339                         printf("would prune %s", message);
 340                 else if (cb->cmd->verbose)
 341                         printf("prune %s", message);
 342         } else {
 343                 if (cb->newlog) {
 344                         char sign = (tz < 0) ? '-' : '+';
 345                         int zone = (tz < 0) ? (-tz) : tz;
 346                         fprintf(cb->newlog, "%s %s %s %lu %c%04d\t%s",
 347                                 sha1_to_hex(osha1), sha1_to_hex(nsha1),
 348                                 email, timestamp, sign, zone,
 349                                 message);
 350                         hashcpy(cb->last_kept_sha1, nsha1);
 351                 }
 352                 if (cb->cmd->verbose)
 353                         printf("keep %s", message);
 354         }
 355         return 0;
 356 }
 357
 358 static int push_tip_to_list(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
 359 {
 360         struct commit_list **list = cb_data;
 361         struct commit *tip_commit;
 362         if (flags & REF_ISSYMREF)
 363                 return 0;
 364         tip_commit = lookup_commit_reference_gently(sha1, 1);
 365         if (!tip_commit)
 366                 return 0;
 367         commit_list_insert(tip_commit, list);
 368         return 0;
 369 }
 370
 371 static void reflog_expiry_prepare(const char *refname,
 372                                   const unsigned char *sha1,
 373                                   struct expire_reflog_cb *cb)
 374 {
 375         if (!cb->cmd->expire_unreachable || !strcmp(refname, "HEAD")) {
 376                 cb->tip_commit = NULL;
 377                 cb->unreachable_expire_kind = UE_HEAD;
 378         } else {
 379                 cb->tip_commit = lookup_commit_reference_gently(sha1, 1);
 380                 if (!cb->tip_commit)
 381                         cb->unreachable_expire_kind = UE_ALWAYS;
 382                 else
 383                         cb->unreachable_expire_kind = UE_NORMAL;
 384         }
 385
 386         if (cb->cmd->expire_unreachable <= cb->cmd->expire_total)
 387                 cb->unreachable_expire_kind = UE_ALWAYS;
 388
 389         cb->mark_list = NULL;
 390         cb->tips = NULL;
 391         if (cb->unreachable_expire_kind != UE_ALWAYS) {
 392                 if (cb->unreachable_expire_kind == UE_HEAD) {
 393                         struct commit_list *elem;
 394                         for_each_ref(push_tip_to_list, &cb->tips);
 395                         for (elem = cb->tips; elem; elem = elem->next)
 396                                 commit_list_insert(elem->item, &cb->mark_list);
 397                 } else {
 398                         commit_list_insert(cb->tip_commit, &cb->mark_list);
 399                 }
 400                 cb->mark_limit = cb->cmd->expire_total;
 401                 mark_reachable(cb);
 402         }
 403 }
 404
 405 static void reflog_expiry_cleanup(struct expire_reflog_cb *cb)
 406 {
 407         if (cb->unreachable_expire_kind != UE_ALWAYS) {
 408                 if (cb->unreachable_expire_kind == UE_HEAD) {
 409                         struct commit_list *elem;
 410                         for (elem = cb->tips; elem; elem = elem->next)
 411                                 clear_commit_marks(elem->item, REACHABLE);
 412                         free_commit_list(cb->tips);
 413                 } else {
 414                         clear_commit_marks(cb->tip_commit, REACHABLE);
 415                 }
 416         }
 417 }
 418
 419 static int expire_reflog(const char *refname, const unsigned char *sha1,
 420                          unsigned int flags, struct cmd_reflog_expire_cb *cmd)
 421 {
 422         static struct lock_file reflog_lock;
 423         struct expire_reflog_cb cb;
 424         struct ref_lock *lock;
 425         char *log_file;
 426         int status = 0;
 427
 428         memset(&cb, 0, sizeof(cb));
 429
 430         /*
 431          * The reflog file is locked by holding the lock on the
 432          * reference itself, plus we might need to update the
 433          * reference if --updateref was specified:
 434          */
 435         lock = lock_any_ref_for_update(refname, sha1, 0, NULL);
 436         if (!lock)
 437                 return error("cannot lock ref '%s'", refname);
 438         if (!reflog_exists(refname)) {
 439                 unlock_ref(lock);
 440                 return 0;
 441         }
 442
 443         log_file = git_pathdup("logs/%s", refname);
 444         if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 445                 /*
 446                  * Even though holding $GIT_DIR/logs/$reflog.lock has
 447                  * no locking implications, we use the lock_file
 448                  * machinery here anyway because it does a lot of the
 449                  * work we need, including cleaning up if the program
 450                  * exits unexpectedly.
 451                  */
 452                 if (hold_lock_file_for_update(&reflog_lock, log_file, 0) < 0) {
 453                         struct strbuf err = STRBUF_INIT;
 454                         unable_to_lock_message(log_file, errno, &err);
 455                         error("%s", err.buf);
 456                         strbuf_release(&err);
 457                         goto failure;
 458                 }
 459                 cb.newlog = fdopen_lock_file(&reflog_lock, "w");
 460                 if (!cb.newlog) {
 461                         error("cannot fdopen %s (%s)",
 462                               reflog_lock.filename.buf, strerror(errno));
 463                         goto failure;
 464                 }
 465         }
 466
 467         cb.cmd = cmd;
 468
 469         reflog_expiry_prepare(refname, sha1, &cb);
 470         for_each_reflog_ent(refname, expire_reflog_ent, &cb);
 471         reflog_expiry_cleanup(&cb);
 472
 473         if (!(flags & EXPIRE_REFLOGS_DRY_RUN)) {
 474                 if (close_lock_file(&reflog_lock)) {
 475                         status |= error("couldn't write %s: %s", log_file,
 476                                         strerror(errno));
 477                 } else if ((flags & EXPIRE_REFLOGS_UPDATE_REF) &&
 478                         (write_in_full(lock->lock_fd,
 479                                 sha1_to_hex(cb.last_kept_sha1), 40) != 40 ||
 480                          write_str_in_full(lock->lock_fd, "\n") != 1 ||
 481                          close_ref(lock) < 0)) {
 482                         status |= error("couldn't write %s",
 483                                         lock->lk->filename.buf);
 484                         rollback_lock_file(&reflog_lock);
 485                 } else if (commit_lock_file(&reflog_lock)) {
 486                         status |= error("unable to commit reflog '%s' (%s)",
 487                                         log_file, strerror(errno));
 488                 } else if ((flags & EXPIRE_REFLOGS_UPDATE_REF) && commit_ref(lock)) {
 489                         status |= error("couldn't set %s", lock->ref_name);
 490                 }
 491         }
 492         free(log_file);
 493         unlock_ref(lock);
 494         return status;
 495
 496  failure:
 497         rollback_lock_file(&reflog_lock);
 498         free(log_file);
 499         unlock_ref(lock);
 500         return -1;
 501 }
 502
 503 static int collect_reflog(const char *ref, const unsigned char *sha1, int unused, void *cb_data)
 504 {
 505         struct collected_reflog *e;
 506         struct collect_reflog_cb *cb = cb_data;
 507         size_t namelen = strlen(ref);
 508
 509         e = xmalloc(sizeof(*e) + namelen + 1);
 510         hashcpy(e->sha1, sha1);
 511         memcpy(e->reflog, ref, namelen + 1);
 512         ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
 513         cb->e[cb->nr++] = e;
 514         return 0;
 515 }
 516
 517 static struct reflog_expire_cfg {
 518         struct reflog_expire_cfg *next;
 519         unsigned long expire_total;
 520         unsigned long expire_unreachable;
 521         size_t len;
 522         char pattern[FLEX_ARRAY];
 523 } *reflog_expire_cfg, **reflog_expire_cfg_tail;
 524
 525 static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
 526 {
 527         struct reflog_expire_cfg *ent;
 528
 529         if (!reflog_expire_cfg_tail)
 530                 reflog_expire_cfg_tail = &reflog_expire_cfg;
 531
 532         for (ent = reflog_expire_cfg; ent; ent = ent->next)
 533                 if (ent->len == len &&
 534                     !memcmp(ent->pattern, pattern, len))
 535                         return ent;
 536
 537         ent = xcalloc(1, (sizeof(*ent) + len));
 538         memcpy(ent->pattern, pattern, len);
 539         ent->len = len;
 540         *reflog_expire_cfg_tail = ent;
 541         reflog_expire_cfg_tail = &(ent->next);
 542         return ent;
 543 }
 544
 545 static int parse_expire_cfg_value(const char *var, const char *value, unsigned long *expire)
 546 {
 547         if (!value)
 548                 return config_error_nonbool(var);
 549         if (parse_expiry_date(value, expire))
 550                 return error(_("%s' for '%s' is not a valid timestamp"),
 551                              value, var);
 552         return 0;
 553 }
 554
 555 /* expiry timer slot */
 556 #define EXPIRE_TOTAL   01
 557 #define EXPIRE_UNREACH 02
 558
 559 static int reflog_expire_config(const char *var, const char *value, void *cb)
 560 {
 561         const char *pattern, *key;
 562         int pattern_len;
 563         unsigned long expire;
 564         int slot;
 565         struct reflog_expire_cfg *ent;
 566
 567         if (parse_config_key(var, "gc", &pattern, &pattern_len, &key) < 0)
 568                 return git_default_config(var, value, cb);
 569
 570         if (!strcmp(key, "reflogexpire")) {
 571                 slot = EXPIRE_TOTAL;
 572                 if (parse_expire_cfg_value(var, value, &expire))
 573                         return -1;
 574         } else if (!strcmp(key, "reflogexpireunreachable")) {
 575                 slot = EXPIRE_UNREACH;
 576                 if (parse_expire_cfg_value(var, value, &expire))
 577                         return -1;
 578         } else
 579                 return git_default_config(var, value, cb);
 580
 581         if (!pattern) {
 582                 switch (slot) {
 583                 case EXPIRE_TOTAL:
 584                         default_reflog_expire = expire;
 585                         break;
 586                 case EXPIRE_UNREACH:
 587                         default_reflog_expire_unreachable = expire;
 588                         break;
 589                 }
 590                 return 0;
 591         }
 592
 593         ent = find_cfg_ent(pattern, pattern_len);
 594         if (!ent)
 595                 return -1;
 596         switch (slot) {
 597         case EXPIRE_TOTAL:
 598                 ent->expire_total = expire;
 599                 break;
 600         case EXPIRE_UNREACH:
 601                 ent->expire_unreachable = expire;
 602                 break;
 603         }
 604         return 0;
 605 }
 606
 607 static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
 608 {
 609         struct reflog_expire_cfg *ent;
 610
 611         if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
 612                 return; /* both given explicitly -- nothing to tweak */
 613
 614         for (ent = reflog_expire_cfg; ent; ent = ent->next) {
 615                 if (!wildmatch(ent->pattern, ref, 0, NULL)) {
 616                         if (!(slot & EXPIRE_TOTAL))
 617                                 cb->expire_total = ent->expire_total;
 618                         if (!(slot & EXPIRE_UNREACH))
 619                                 cb->expire_unreachable = ent->expire_unreachable;
 620                         return;
 621                 }
 622         }
 623
 624         /*
 625          * If unconfigured, make stash never expire
 626          */
 627         if (!strcmp(ref, "refs/stash")) {
 628                 if (!(slot & EXPIRE_TOTAL))
 629                         cb->expire_total = 0;
 630                 if (!(slot & EXPIRE_UNREACH))
 631                         cb->expire_unreachable = 0;
 632                 return;
 633         }
 634
 635         /* Nothing matched -- use the default value */
 636         if (!(slot & EXPIRE_TOTAL))
 637                 cb->expire_total = default_reflog_expire;
 638         if (!(slot & EXPIRE_UNREACH))
 639                 cb->expire_unreachable = default_reflog_expire_unreachable;
 640 }
 641
 642 static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
 643 {
 644         struct cmd_reflog_expire_cb cb;
 645         unsigned long now = time(NULL);
 646         int i, status, do_all;
 647         int explicit_expiry = 0;
 648         unsigned int flags = 0;
 649
 650         default_reflog_expire_unreachable = now - 30 * 24 * 3600;
 651         default_reflog_expire = now - 90 * 24 * 3600;
 652         git_config(reflog_expire_config, NULL);
 653
 654         save_commit_buffer = 0;
 655         do_all = status = 0;
 656         memset(&cb, 0, sizeof(cb));
 657
 658         cb.expire_total = default_reflog_expire;
 659         cb.expire_unreachable = default_reflog_expire_unreachable;
 660
 661         for (i = 1; i < argc; i++) {
 662                 const char *arg = argv[i];
 663                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 664                         flags |= EXPIRE_REFLOGS_DRY_RUN;
 665                 else if (starts_with(arg, "--expire=")) {
 666                         if (parse_expiry_date(arg + 9, &cb.expire_total))
 667                                 die(_("'%s' is not a valid timestamp"), arg);
 668                         explicit_expiry |= EXPIRE_TOTAL;
 669                 }
 670                 else if (starts_with(arg, "--expire-unreachable=")) {
 671                         if (parse_expiry_date(arg + 21, &cb.expire_unreachable))
 672                                 die(_("'%s' is not a valid timestamp"), arg);
 673                         explicit_expiry |= EXPIRE_UNREACH;
 674                 }
 675                 else if (!strcmp(arg, "--stale-fix"))
 676                         cb.stalefix = 1;
 677                 else if (!strcmp(arg, "--rewrite"))
 678                         cb.rewrite = 1;
 679                 else if (!strcmp(arg, "--updateref"))
 680                         flags |= EXPIRE_REFLOGS_UPDATE_REF;
 681                 else if (!strcmp(arg, "--all"))
 682                         do_all = 1;
 683                 else if (!strcmp(arg, "--verbose"))
 684                         cb.verbose = 1;
 685                 else if (!strcmp(arg, "--")) {
 686                         i++;
 687                         break;
 688                 }
 689                 else if (arg[0] == '-')
 690                         usage(reflog_expire_usage);
 691                 else
 692                         break;
 693         }
 694
 695         /*
 696          * We can trust the commits and objects reachable from refs
 697          * even in older repository.  We cannot trust what's reachable
 698          * from reflog if the repository was pruned with older git.
 699          */
 700         if (cb.stalefix) {
 701                 init_revisions(&cb.revs, prefix);
 702                 if (cb.verbose)
 703                         printf("Marking reachable objects...");
 704                 mark_reachable_objects(&cb.revs, 0, 0, NULL);
 705                 if (cb.verbose)
 706                         putchar('\n');
 707         }
 708
 709         if (do_all) {
 710                 struct collect_reflog_cb collected;
 711                 int i;
 712
 713                 memset(&collected, 0, sizeof(collected));
 714                 for_each_reflog(collect_reflog, &collected);
 715                 for (i = 0; i < collected.nr; i++) {
 716                         struct collected_reflog *e = collected.e[i];
 717                         set_reflog_expiry_param(&cb, explicit_expiry, e->reflog);
 718                         status |= expire_reflog(e->reflog, e->sha1, flags, &cb);
 719                         free(e);
 720                 }
 721                 free(collected.e);
 722         }
 723
 724         for (; i < argc; i++) {
 725                 char *ref;
 726                 unsigned char sha1[20];
 727                 if (!dwim_log(argv[i], strlen(argv[i]), sha1, &ref)) {
 728                         status |= error("%s points nowhere!", argv[i]);
 729                         continue;
 730                 }
 731                 set_reflog_expiry_param(&cb, explicit_expiry, ref);
 732                 status |= expire_reflog(ref, sha1, flags, &cb);
 733         }
 734         return status;
 735 }
 736
 737 static int count_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 738                 const char *email, unsigned long timestamp, int tz,
 739                 const char *message, void *cb_data)
 740 {
 741         struct cmd_reflog_expire_cb *cb = cb_data;
 742         if (!cb->expire_total || timestamp < cb->expire_total)
 743                 cb->recno++;
 744         return 0;
 745 }
 746
 747 static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
 748 {
 749         struct cmd_reflog_expire_cb cb;
 750         int i, status = 0;
 751         unsigned int flags = 0;
 752
 753         memset(&cb, 0, sizeof(cb));
 754
 755         for (i = 1; i < argc; i++) {
 756                 const char *arg = argv[i];
 757                 if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
 758                         flags |= EXPIRE_REFLOGS_DRY_RUN;
 759                 else if (!strcmp(arg, "--rewrite"))
 760                         cb.rewrite = 1;
 761                 else if (!strcmp(arg, "--updateref"))
 762                         flags |= EXPIRE_REFLOGS_UPDATE_REF;
 763                 else if (!strcmp(arg, "--verbose"))
 764                         cb.verbose = 1;
 765                 else if (!strcmp(arg, "--")) {
 766                         i++;
 767                         break;
 768                 }
 769                 else if (arg[0] == '-')
 770                         usage(reflog_delete_usage);
 771                 else
 772                         break;
 773         }
 774
 775         if (argc - i < 1)
 776                 return error("Nothing to delete?");
 777
 778         for ( ; i < argc; i++) {
 779                 const char *spec = strstr(argv[i], "@{");
 780                 unsigned char sha1[20];
 781                 char *ep, *ref;
 782                 int recno;
 783
 784                 if (!spec) {
 785                         status |= error("Not a reflog: %s", argv[i]);
 786                         continue;
 787                 }
 788
 789                 if (!dwim_log(argv[i], spec - argv[i], sha1, &ref)) {
 790                         status |= error("no reflog for '%s'", argv[i]);
 791                         continue;
 792                 }
 793
 794                 recno = strtoul(spec + 2, &ep, 10);
 795                 if (*ep == '}') {
 796                         cb.recno = -recno;
 797                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
 798                 } else {
 799                         cb.expire_total = approxidate(spec + 2);
 800                         for_each_reflog_ent(ref, count_reflog_ent, &cb);
 801                         cb.expire_total = 0;
 802                 }
 803
 804                 status |= expire_reflog(ref, sha1, flags, &cb);
 805                 free(ref);
 806         }
 807         return status;
 808 }
 809
 810 /*
 811  * main "reflog"
 812  */
 813
 814 static const char reflog_usage[] =
 815 "git reflog [ show | expire | delete ]";
 816
 817 int cmd_reflog(int argc, const char **argv, const char *prefix)
 818 {
 819         if (argc > 1 && !strcmp(argv[1], "-h"))
 820                 usage(reflog_usage);
 821
 822         /* With no command, we default to showing it. */
 823         if (argc < 2 || *argv[1] == '-')
 824                 return cmd_log_reflog(argc, argv, prefix);
 825
 826         if (!strcmp(argv[1], "show"))
 827                 return cmd_log_reflog(argc - 1, argv + 1, prefix);
 828
 829         if (!strcmp(argv[1], "expire"))
 830                 return cmd_reflog_expire(argc - 1, argv + 1, prefix);
 831
 832         if (!strcmp(argv[1], "delete"))
 833                 return cmd_reflog_delete(argc - 1, argv + 1, prefix);
 834
 835         return cmd_log_reflog(argc, argv, prefix);
 836 }