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