git.oblomov.eu Git - git/blob - packfile.c

   1 #include "cache.h"
   2 #include "list.h"
   3 #include "pack.h"
   4 #include "repository.h"
   5 #include "dir.h"
   6 #include "mergesort.h"
   7 #include "packfile.h"
   8 #include "delta.h"
   9 #include "streaming.h"
  10 #include "sha1-lookup.h"
  11 #include "commit.h"
  12 #include "object.h"
  13 #include "tag.h"
  14 #include "tree-walk.h"
  15 #include "tree.h"
  16 #include "object-store.h"
  17 #include "midx.h"
  18 #include "commit-graph.h"
  19 #include "promisor-remote.h"
  20
  21 char *odb_pack_name(struct strbuf *buf,
  22                     const unsigned char *hash,
  23                     const char *ext)
  24 {
  25         strbuf_reset(buf);
  26         strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
  27                     hash_to_hex(hash), ext);
  28         return buf->buf;
  29 }
  30
  31 char *sha1_pack_name(const unsigned char *sha1)
  32 {
  33         static struct strbuf buf = STRBUF_INIT;
  34         return odb_pack_name(&buf, sha1, "pack");
  35 }
  36
  37 char *sha1_pack_index_name(const unsigned char *sha1)
  38 {
  39         static struct strbuf buf = STRBUF_INIT;
  40         return odb_pack_name(&buf, sha1, "idx");
  41 }
  42
  43 static unsigned int pack_used_ctr;
  44 static unsigned int pack_mmap_calls;
  45 static unsigned int peak_pack_open_windows;
  46 static unsigned int pack_open_windows;
  47 static unsigned int pack_open_fds;
  48 static unsigned int pack_max_fds;
  49 static size_t peak_pack_mapped;
  50 static size_t pack_mapped;
  51
  52 #define SZ_FMT PRIuMAX
  53 static inline uintmax_t sz_fmt(size_t s) { return s; }
  54
  55 void pack_report(void)
  56 {
  57         fprintf(stderr,
  58                 "pack_report: getpagesize()            = %10" SZ_FMT "\n"
  59                 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
  60                 "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
  61                 sz_fmt(getpagesize()),
  62                 sz_fmt(packed_git_window_size),
  63                 sz_fmt(packed_git_limit));
  64         fprintf(stderr,
  65                 "pack_report: pack_used_ctr            = %10u\n"
  66                 "pack_report: pack_mmap_calls          = %10u\n"
  67                 "pack_report: pack_open_windows        = %10u / %10u\n"
  68                 "pack_report: pack_mapped              = "
  69                         "%10" SZ_FMT " / %10" SZ_FMT "\n",
  70                 pack_used_ctr,
  71                 pack_mmap_calls,
  72                 pack_open_windows, peak_pack_open_windows,
  73                 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
  74 }
  75
  76 /*
  77  * Open and mmap the index file at path, perform a couple of
  78  * consistency checks, then record its information to p.  Return 0 on
  79  * success.
  80  */
  81 static int check_packed_git_idx(const char *path, struct packed_git *p)
  82 {
  83         void *idx_map;
  84         size_t idx_size;
  85         int fd = git_open(path), ret;
  86         struct stat st;
  87         const unsigned int hashsz = the_hash_algo->rawsz;
  88
  89         if (fd < 0)
  90                 return -1;
  91         if (fstat(fd, &st)) {
  92                 close(fd);
  93                 return -1;
  94         }
  95         idx_size = xsize_t(st.st_size);
  96         if (idx_size < 4 * 256 + hashsz + hashsz) {
  97                 close(fd);
  98                 return error("index file %s is too small", path);
  99         }
 100         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 101         close(fd);
 102
 103         ret = load_idx(path, hashsz, idx_map, idx_size, p);
 104
 105         if (ret)
 106                 munmap(idx_map, idx_size);
 107
 108         return ret;
 109 }
 110
 111 int load_idx(const char *path, const unsigned int hashsz, void *idx_map,
 112              size_t idx_size, struct packed_git *p)
 113 {
 114         struct pack_idx_header *hdr = idx_map;
 115         uint32_t version, nr, i, *index;
 116
 117         if (idx_size < 4 * 256 + hashsz + hashsz)
 118                 return error("index file %s is too small", path);
 119         if (idx_map == NULL)
 120                 return error("empty data");
 121
 122         if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 123                 version = ntohl(hdr->idx_version);
 124                 if (version < 2 || version > 2)
 125                         return error("index file %s is version %"PRIu32
 126                                      " and is not supported by this binary"
 127                                      " (try upgrading GIT to a newer version)",
 128                                      path, version);
 129         } else
 130                 version = 1;
 131
 132         nr = 0;
 133         index = idx_map;
 134         if (version > 1)
 135                 index += 2;  /* skip index header */
 136         for (i = 0; i < 256; i++) {
 137                 uint32_t n = ntohl(index[i]);
 138                 if (n < nr)
 139                         return error("non-monotonic index %s", path);
 140                 nr = n;
 141         }
 142
 143         if (version == 1) {
 144                 /*
 145                  * Total size:
 146                  *  - 256 index entries 4 bytes each
 147                  *  - 24-byte entries * nr (object ID + 4-byte offset)
 148                  *  - hash of the packfile
 149                  *  - file checksum
 150                  */
 151                 if (idx_size != 4 * 256 + nr * (hashsz + 4) + hashsz + hashsz)
 152                         return error("wrong index v1 file size in %s", path);
 153         } else if (version == 2) {
 154                 /*
 155                  * Minimum size:
 156                  *  - 8 bytes of header
 157                  *  - 256 index entries 4 bytes each
 158                  *  - object ID entry * nr
 159                  *  - 4-byte crc entry * nr
 160                  *  - 4-byte offset entry * nr
 161                  *  - hash of the packfile
 162                  *  - file checksum
 163                  * And after the 4-byte offset table might be a
 164                  * variable sized table containing 8-byte entries
 165                  * for offsets larger than 2^31.
 166                  */
 167                 unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
 168                 unsigned long max_size = min_size;
 169                 if (nr)
 170                         max_size += (nr - 1)*8;
 171                 if (idx_size < min_size || idx_size > max_size)
 172                         return error("wrong index v2 file size in %s", path);
 173                 if (idx_size != min_size &&
 174                     /*
 175                      * make sure we can deal with large pack offsets.
 176                      * 31-bit signed offset won't be enough, neither
 177                      * 32-bit unsigned one will be.
 178                      */
 179                     (sizeof(off_t) <= 4))
 180                         return error("pack too large for current definition of off_t in %s", path);
 181         }
 182
 183         p->index_version = version;
 184         p->index_data = idx_map;
 185         p->index_size = idx_size;
 186         p->num_objects = nr;
 187         return 0;
 188 }
 189
 190 int open_pack_index(struct packed_git *p)
 191 {
 192         char *idx_name;
 193         size_t len;
 194         int ret;
 195
 196         if (p->index_data)
 197                 return 0;
 198
 199         if (!strip_suffix(p->pack_name, ".pack", &len))
 200                 BUG("pack_name does not end in .pack");
 201         idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 202         ret = check_packed_git_idx(idx_name, p);
 203         free(idx_name);
 204         return ret;
 205 }
 206
 207 uint32_t get_pack_fanout(struct packed_git *p, uint32_t value)
 208 {
 209         const uint32_t *level1_ofs = p->index_data;
 210
 211         if (!level1_ofs) {
 212                 if (open_pack_index(p))
 213                         return 0;
 214                 level1_ofs = p->index_data;
 215         }
 216
 217         if (p->index_version > 1) {
 218                 level1_ofs += 2;
 219         }
 220
 221         return ntohl(level1_ofs[value]);
 222 }
 223
 224 static struct packed_git *alloc_packed_git(int extra)
 225 {
 226         struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
 227         memset(p, 0, sizeof(*p));
 228         p->pack_fd = -1;
 229         return p;
 230 }
 231
 232 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 233 {
 234         const char *path = sha1_pack_name(sha1);
 235         size_t alloc = st_add(strlen(path), 1);
 236         struct packed_git *p = alloc_packed_git(alloc);
 237
 238         memcpy(p->pack_name, path, alloc); /* includes NUL */
 239         hashcpy(p->hash, sha1);
 240         if (check_packed_git_idx(idx_path, p)) {
 241                 free(p);
 242                 return NULL;
 243         }
 244
 245         return p;
 246 }
 247
 248 static void scan_windows(struct packed_git *p,
 249         struct packed_git **lru_p,
 250         struct pack_window **lru_w,
 251         struct pack_window **lru_l)
 252 {
 253         struct pack_window *w, *w_l;
 254
 255         for (w_l = NULL, w = p->windows; w; w = w->next) {
 256                 if (!w->inuse_cnt) {
 257                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 258                                 *lru_p = p;
 259                                 *lru_w = w;
 260                                 *lru_l = w_l;
 261                         }
 262                 }
 263                 w_l = w;
 264         }
 265 }
 266
 267 static int unuse_one_window(struct packed_git *current)
 268 {
 269         struct packed_git *p, *lru_p = NULL;
 270         struct pack_window *lru_w = NULL, *lru_l = NULL;
 271
 272         if (current)
 273                 scan_windows(current, &lru_p, &lru_w, &lru_l);
 274         for (p = the_repository->objects->packed_git; p; p = p->next)
 275                 scan_windows(p, &lru_p, &lru_w, &lru_l);
 276         if (lru_p) {
 277                 munmap(lru_w->base, lru_w->len);
 278                 pack_mapped -= lru_w->len;
 279                 if (lru_l)
 280                         lru_l->next = lru_w->next;
 281                 else
 282                         lru_p->windows = lru_w->next;
 283                 free(lru_w);
 284                 pack_open_windows--;
 285                 return 1;
 286         }
 287         return 0;
 288 }
 289
 290 void close_pack_windows(struct packed_git *p)
 291 {
 292         while (p->windows) {
 293                 struct pack_window *w = p->windows;
 294
 295                 if (w->inuse_cnt)
 296                         die("pack '%s' still has open windows to it",
 297                             p->pack_name);
 298                 munmap(w->base, w->len);
 299                 pack_mapped -= w->len;
 300                 pack_open_windows--;
 301                 p->windows = w->next;
 302                 free(w);
 303         }
 304 }
 305
 306 int close_pack_fd(struct packed_git *p)
 307 {
 308         if (p->pack_fd < 0)
 309                 return 0;
 310
 311         close(p->pack_fd);
 312         pack_open_fds--;
 313         p->pack_fd = -1;
 314
 315         return 1;
 316 }
 317
 318 void close_pack_index(struct packed_git *p)
 319 {
 320         if (p->index_data) {
 321                 munmap((void *)p->index_data, p->index_size);
 322                 p->index_data = NULL;
 323         }
 324 }
 325
 326 void close_pack(struct packed_git *p)
 327 {
 328         close_pack_windows(p);
 329         close_pack_fd(p);
 330         close_pack_index(p);
 331 }
 332
 333 void close_object_store(struct raw_object_store *o)
 334 {
 335         struct packed_git *p;
 336
 337         for (p = o->packed_git; p; p = p->next)
 338                 if (p->do_not_close)
 339                         BUG("want to close pack marked 'do-not-close'");
 340                 else
 341                         close_pack(p);
 342
 343         if (o->multi_pack_index) {
 344                 close_midx(o->multi_pack_index);
 345                 o->multi_pack_index = NULL;
 346         }
 347
 348         close_commit_graph(o);
 349 }
 350
 351 void unlink_pack_path(const char *pack_name, int force_delete)
 352 {
 353         static const char *exts[] = {".pack", ".idx", ".keep", ".bitmap", ".promisor"};
 354         int i;
 355         struct strbuf buf = STRBUF_INIT;
 356         size_t plen;
 357
 358         strbuf_addstr(&buf, pack_name);
 359         strip_suffix_mem(buf.buf, &buf.len, ".pack");
 360         plen = buf.len;
 361
 362         if (!force_delete) {
 363                 strbuf_addstr(&buf, ".keep");
 364                 if (!access(buf.buf, F_OK)) {
 365                         strbuf_release(&buf);
 366                         return;
 367                 }
 368         }
 369
 370         for (i = 0; i < ARRAY_SIZE(exts); i++) {
 371                 strbuf_setlen(&buf, plen);
 372                 strbuf_addstr(&buf, exts[i]);
 373                 unlink(buf.buf);
 374         }
 375
 376         strbuf_release(&buf);
 377 }
 378
 379 /*
 380  * The LRU pack is the one with the oldest MRU window, preferring packs
 381  * with no used windows, or the oldest mtime if it has no windows allocated.
 382  */
 383 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 384 {
 385         struct pack_window *w, *this_mru_w;
 386         int has_windows_inuse = 0;
 387
 388         /*
 389          * Reject this pack if it has windows and the previously selected
 390          * one does not.  If this pack does not have windows, reject
 391          * it if the pack file is newer than the previously selected one.
 392          */
 393         if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 394                 return;
 395
 396         for (w = this_mru_w = p->windows; w; w = w->next) {
 397                 /*
 398                  * Reject this pack if any of its windows are in use,
 399                  * but the previously selected pack did not have any
 400                  * inuse windows.  Otherwise, record that this pack
 401                  * has windows in use.
 402                  */
 403                 if (w->inuse_cnt) {
 404                         if (*accept_windows_inuse)
 405                                 has_windows_inuse = 1;
 406                         else
 407                                 return;
 408                 }
 409
 410                 if (w->last_used > this_mru_w->last_used)
 411                         this_mru_w = w;
 412
 413                 /*
 414                  * Reject this pack if it has windows that have been
 415                  * used more recently than the previously selected pack.
 416                  * If the previously selected pack had windows inuse and
 417                  * we have not encountered a window in this pack that is
 418                  * inuse, skip this check since we prefer a pack with no
 419                  * inuse windows to one that has inuse windows.
 420                  */
 421                 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 422                     this_mru_w->last_used > (*mru_w)->last_used)
 423                         return;
 424         }
 425
 426         /*
 427          * Select this pack.
 428          */
 429         *mru_w = this_mru_w;
 430         *lru_p = p;
 431         *accept_windows_inuse = has_windows_inuse;
 432 }
 433
 434 static int close_one_pack(void)
 435 {
 436         struct packed_git *p, *lru_p = NULL;
 437         struct pack_window *mru_w = NULL;
 438         int accept_windows_inuse = 1;
 439
 440         for (p = the_repository->objects->packed_git; p; p = p->next) {
 441                 if (p->pack_fd == -1)
 442                         continue;
 443                 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 444         }
 445
 446         if (lru_p)
 447                 return close_pack_fd(lru_p);
 448
 449         return 0;
 450 }
 451
 452 static unsigned int get_max_fd_limit(void)
 453 {
 454 #ifdef RLIMIT_NOFILE
 455         {
 456                 struct rlimit lim;
 457
 458                 if (!getrlimit(RLIMIT_NOFILE, &lim))
 459                         return lim.rlim_cur;
 460         }
 461 #endif
 462
 463 #ifdef _SC_OPEN_MAX
 464         {
 465                 long open_max = sysconf(_SC_OPEN_MAX);
 466                 if (0 < open_max)
 467                         return open_max;
 468                 /*
 469                  * Otherwise, we got -1 for one of the two
 470                  * reasons:
 471                  *
 472                  * (1) sysconf() did not understand _SC_OPEN_MAX
 473                  *     and signaled an error with -1; or
 474                  * (2) sysconf() said there is no limit.
 475                  *
 476                  * We _could_ clear errno before calling sysconf() to
 477                  * tell these two cases apart and return a huge number
 478                  * in the latter case to let the caller cap it to a
 479                  * value that is not so selfish, but letting the
 480                  * fallback OPEN_MAX codepath take care of these cases
 481                  * is a lot simpler.
 482                  */
 483         }
 484 #endif
 485
 486 #ifdef OPEN_MAX
 487         return OPEN_MAX;
 488 #else
 489         return 1; /* see the caller ;-) */
 490 #endif
 491 }
 492
 493 const char *pack_basename(struct packed_git *p)
 494 {
 495         const char *ret = strrchr(p->pack_name, '/');
 496         if (ret)
 497                 ret = ret + 1; /* skip past slash */
 498         else
 499                 ret = p->pack_name; /* we only have a base */
 500         return ret;
 501 }
 502
 503 /*
 504  * Do not call this directly as this leaks p->pack_fd on error return;
 505  * call open_packed_git() instead.
 506  */
 507 static int open_packed_git_1(struct packed_git *p)
 508 {
 509         struct stat st;
 510         struct pack_header hdr;
 511         unsigned char hash[GIT_MAX_RAWSZ];
 512         unsigned char *idx_hash;
 513         ssize_t read_result;
 514         const unsigned hashsz = the_hash_algo->rawsz;
 515
 516         if (!p->index_data) {
 517                 struct multi_pack_index *m;
 518                 const char *pack_name = pack_basename(p);
 519
 520                 for (m = the_repository->objects->multi_pack_index;
 521                      m; m = m->next) {
 522                         if (midx_contains_pack(m, pack_name))
 523                                 break;
 524                 }
 525
 526                 if (!m && open_pack_index(p))
 527                         return error("packfile %s index unavailable", p->pack_name);
 528         }
 529
 530         if (!pack_max_fds) {
 531                 unsigned int max_fds = get_max_fd_limit();
 532
 533                 /* Save 3 for stdin/stdout/stderr, 22 for work */
 534                 if (25 < max_fds)
 535                         pack_max_fds = max_fds - 25;
 536                 else
 537                         pack_max_fds = 1;
 538         }
 539
 540         while (pack_max_fds <= pack_open_fds && close_one_pack())
 541                 ; /* nothing */
 542
 543         p->pack_fd = git_open(p->pack_name);
 544         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 545                 return -1;
 546         pack_open_fds++;
 547
 548         /* If we created the struct before we had the pack we lack size. */
 549         if (!p->pack_size) {
 550                 if (!S_ISREG(st.st_mode))
 551                         return error("packfile %s not a regular file", p->pack_name);
 552                 p->pack_size = st.st_size;
 553         } else if (p->pack_size != st.st_size)
 554                 return error("packfile %s size changed", p->pack_name);
 555
 556         /* Verify we recognize this pack file format. */
 557         read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
 558         if (read_result < 0)
 559                 return error_errno("error reading from %s", p->pack_name);
 560         if (read_result != sizeof(hdr))
 561                 return error("file %s is far too short to be a packfile", p->pack_name);
 562         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 563                 return error("file %s is not a GIT packfile", p->pack_name);
 564         if (!pack_version_ok(hdr.hdr_version))
 565                 return error("packfile %s is version %"PRIu32" and not"
 566                         " supported (try upgrading GIT to a newer version)",
 567                         p->pack_name, ntohl(hdr.hdr_version));
 568
 569         /* Skip index checking if in multi-pack-index */
 570         if (!p->index_data)
 571                 return 0;
 572
 573         /* Verify the pack matches its index. */
 574         if (p->num_objects != ntohl(hdr.hdr_entries))
 575                 return error("packfile %s claims to have %"PRIu32" objects"
 576                              " while index indicates %"PRIu32" objects",
 577                              p->pack_name, ntohl(hdr.hdr_entries),
 578                              p->num_objects);
 579         read_result = pread_in_full(p->pack_fd, hash, hashsz,
 580                                         p->pack_size - hashsz);
 581         if (read_result < 0)
 582                 return error_errno("error reading from %s", p->pack_name);
 583         if (read_result != hashsz)
 584                 return error("packfile %s signature is unavailable", p->pack_name);
 585         idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
 586         if (!hasheq(hash, idx_hash))
 587                 return error("packfile %s does not match index", p->pack_name);
 588         return 0;
 589 }
 590
 591 static int open_packed_git(struct packed_git *p)
 592 {
 593         if (!open_packed_git_1(p))
 594                 return 0;
 595         close_pack_fd(p);
 596         return -1;
 597 }
 598
 599 static int in_window(struct pack_window *win, off_t offset)
 600 {
 601         /* We must promise at least one full hash after the
 602          * offset is available from this window, otherwise the offset
 603          * is not actually in this window and a different window (which
 604          * has that one hash excess) must be used.  This is to support
 605          * the object header and delta base parsing routines below.
 606          */
 607         off_t win_off = win->offset;
 608         return win_off <= offset
 609                 && (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 610 }
 611
 612 unsigned char *use_pack(struct packed_git *p,
 613                 struct pack_window **w_cursor,
 614                 off_t offset,
 615                 unsigned long *left)
 616 {
 617         struct pack_window *win = *w_cursor;
 618
 619         /* Since packfiles end in a hash of their content and it's
 620          * pointless to ask for an offset into the middle of that
 621          * hash, and the in_window function above wouldn't match
 622          * don't allow an offset too close to the end of the file.
 623          */
 624         if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 625                 die("packfile %s cannot be accessed", p->pack_name);
 626         if (offset > (p->pack_size - the_hash_algo->rawsz))
 627                 die("offset beyond end of packfile (truncated pack?)");
 628         if (offset < 0)
 629                 die(_("offset before end of packfile (broken .idx?)"));
 630
 631         if (!win || !in_window(win, offset)) {
 632                 if (win)
 633                         win->inuse_cnt--;
 634                 for (win = p->windows; win; win = win->next) {
 635                         if (in_window(win, offset))
 636                                 break;
 637                 }
 638                 if (!win) {
 639                         size_t window_align = packed_git_window_size / 2;
 640                         off_t len;
 641
 642                         if (p->pack_fd == -1 && open_packed_git(p))
 643                                 die("packfile %s cannot be accessed", p->pack_name);
 644
 645                         win = xcalloc(1, sizeof(*win));
 646                         win->offset = (offset / window_align) * window_align;
 647                         len = p->pack_size - win->offset;
 648                         if (len > packed_git_window_size)
 649                                 len = packed_git_window_size;
 650                         win->len = (size_t)len;
 651                         pack_mapped += win->len;
 652                         while (packed_git_limit < pack_mapped
 653                                 && unuse_one_window(p))
 654                                 ; /* nothing */
 655                         win->base = xmmap_gently(NULL, win->len,
 656                                 PROT_READ, MAP_PRIVATE,
 657                                 p->pack_fd, win->offset);
 658                         if (win->base == MAP_FAILED)
 659                                 die_errno("packfile %s cannot be mapped",
 660                                           p->pack_name);
 661                         if (!win->offset && win->len == p->pack_size
 662                                 && !p->do_not_close)
 663                                 close_pack_fd(p);
 664                         pack_mmap_calls++;
 665                         pack_open_windows++;
 666                         if (pack_mapped > peak_pack_mapped)
 667                                 peak_pack_mapped = pack_mapped;
 668                         if (pack_open_windows > peak_pack_open_windows)
 669                                 peak_pack_open_windows = pack_open_windows;
 670                         win->next = p->windows;
 671                         p->windows = win;
 672                 }
 673         }
 674         if (win != *w_cursor) {
 675                 win->last_used = pack_used_ctr++;
 676                 win->inuse_cnt++;
 677                 *w_cursor = win;
 678         }
 679         offset -= win->offset;
 680         if (left)
 681                 *left = win->len - xsize_t(offset);
 682         return win->base + offset;
 683 }
 684
 685 void unuse_pack(struct pack_window **w_cursor)
 686 {
 687         struct pack_window *w = *w_cursor;
 688         if (w) {
 689                 w->inuse_cnt--;
 690                 *w_cursor = NULL;
 691         }
 692 }
 693
 694 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 695 {
 696         struct stat st;
 697         size_t alloc;
 698         struct packed_git *p;
 699
 700         /*
 701          * Make sure a corresponding .pack file exists and that
 702          * the index looks sane.
 703          */
 704         if (!strip_suffix_mem(path, &path_len, ".idx"))
 705                 return NULL;
 706
 707         /*
 708          * ".promisor" is long enough to hold any suffix we're adding (and
 709          * the use xsnprintf double-checks that)
 710          */
 711         alloc = st_add3(path_len, strlen(".promisor"), 1);
 712         p = alloc_packed_git(alloc);
 713         memcpy(p->pack_name, path, path_len);
 714
 715         xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
 716         if (!access(p->pack_name, F_OK))
 717                 p->pack_keep = 1;
 718
 719         xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
 720         if (!access(p->pack_name, F_OK))
 721                 p->pack_promisor = 1;
 722
 723         xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
 724         if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 725                 free(p);
 726                 return NULL;
 727         }
 728
 729         /* ok, it looks sane as far as we can check without
 730          * actually mapping the pack file.
 731          */
 732         p->pack_size = st.st_size;
 733         p->pack_local = local;
 734         p->mtime = st.st_mtime;
 735         if (path_len < the_hash_algo->hexsz ||
 736             get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->hash))
 737                 hashclr(p->hash);
 738         return p;
 739 }
 740
 741 void install_packed_git(struct repository *r, struct packed_git *pack)
 742 {
 743         if (pack->pack_fd != -1)
 744                 pack_open_fds++;
 745
 746         pack->next = r->objects->packed_git;
 747         r->objects->packed_git = pack;
 748
 749         hashmap_entry_init(&pack->packmap_ent, strhash(pack->pack_name));
 750         hashmap_add(&r->objects->pack_map, &pack->packmap_ent);
 751 }
 752
 753 void (*report_garbage)(unsigned seen_bits, const char *path);
 754
 755 static void report_helper(const struct string_list *list,
 756                           int seen_bits, int first, int last)
 757 {
 758         if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
 759                 return;
 760
 761         for (; first < last; first++)
 762                 report_garbage(seen_bits, list->items[first].string);
 763 }
 764
 765 static void report_pack_garbage(struct string_list *list)
 766 {
 767         int i, baselen = -1, first = 0, seen_bits = 0;
 768
 769         if (!report_garbage)
 770                 return;
 771
 772         string_list_sort(list);
 773
 774         for (i = 0; i < list->nr; i++) {
 775                 const char *path = list->items[i].string;
 776                 if (baselen != -1 &&
 777                     strncmp(path, list->items[first].string, baselen)) {
 778                         report_helper(list, seen_bits, first, i);
 779                         baselen = -1;
 780                         seen_bits = 0;
 781                 }
 782                 if (baselen == -1) {
 783                         const char *dot = strrchr(path, '.');
 784                         if (!dot) {
 785                                 report_garbage(PACKDIR_FILE_GARBAGE, path);
 786                                 continue;
 787                         }
 788                         baselen = dot - path + 1;
 789                         first = i;
 790                 }
 791                 if (!strcmp(path + baselen, "pack"))
 792                         seen_bits |= 1;
 793                 else if (!strcmp(path + baselen, "idx"))
 794                         seen_bits |= 2;
 795         }
 796         report_helper(list, seen_bits, first, list->nr);
 797 }
 798
 799 void for_each_file_in_pack_dir(const char *objdir,
 800                                each_file_in_pack_dir_fn fn,
 801                                void *data)
 802 {
 803         struct strbuf path = STRBUF_INIT;
 804         size_t dirnamelen;
 805         DIR *dir;
 806         struct dirent *de;
 807
 808         strbuf_addstr(&path, objdir);
 809         strbuf_addstr(&path, "/pack");
 810         dir = opendir(path.buf);
 811         if (!dir) {
 812                 if (errno != ENOENT)
 813                         error_errno("unable to open object pack directory: %s",
 814                                     path.buf);
 815                 strbuf_release(&path);
 816                 return;
 817         }
 818         strbuf_addch(&path, '/');
 819         dirnamelen = path.len;
 820         while ((de = readdir(dir)) != NULL) {
 821                 if (is_dot_or_dotdot(de->d_name))
 822                         continue;
 823
 824                 strbuf_setlen(&path, dirnamelen);
 825                 strbuf_addstr(&path, de->d_name);
 826
 827                 fn(path.buf, path.len, de->d_name, data);
 828         }
 829
 830         closedir(dir);
 831         strbuf_release(&path);
 832 }
 833
 834 struct prepare_pack_data {
 835         struct repository *r;
 836         struct string_list *garbage;
 837         int local;
 838         struct multi_pack_index *m;
 839 };
 840
 841 static void prepare_pack(const char *full_name, size_t full_name_len,
 842                          const char *file_name, void *_data)
 843 {
 844         struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
 845         struct packed_git *p;
 846         size_t base_len = full_name_len;
 847
 848         if (strip_suffix_mem(full_name, &base_len, ".idx") &&
 849             !(data->m && midx_contains_pack(data->m, file_name))) {
 850                 struct hashmap_entry hent;
 851                 char *pack_name = xstrfmt("%.*s.pack", (int)base_len, full_name);
 852                 unsigned int hash = strhash(pack_name);
 853                 hashmap_entry_init(&hent, hash);
 854
 855                 /* Don't reopen a pack we already have. */
 856                 if (!hashmap_get(&data->r->objects->pack_map, &hent, pack_name)) {
 857                         p = add_packed_git(full_name, full_name_len, data->local);
 858                         if (p)
 859                                 install_packed_git(data->r, p);
 860                 }
 861                 free(pack_name);
 862         }
 863
 864         if (!report_garbage)
 865                 return;
 866
 867         if (!strcmp(file_name, "multi-pack-index"))
 868                 return;
 869         if (ends_with(file_name, ".idx") ||
 870             ends_with(file_name, ".pack") ||
 871             ends_with(file_name, ".bitmap") ||
 872             ends_with(file_name, ".keep") ||
 873             ends_with(file_name, ".promisor"))
 874                 string_list_append(data->garbage, full_name);
 875         else
 876                 report_garbage(PACKDIR_FILE_GARBAGE, full_name);
 877 }
 878
 879 static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
 880 {
 881         struct prepare_pack_data data;
 882         struct string_list garbage = STRING_LIST_INIT_DUP;
 883
 884         data.m = r->objects->multi_pack_index;
 885
 886         /* look for the multi-pack-index for this object directory */
 887         while (data.m && strcmp(data.m->object_dir, objdir))
 888                 data.m = data.m->next;
 889
 890         data.r = r;
 891         data.garbage = &garbage;
 892         data.local = local;
 893
 894         for_each_file_in_pack_dir(objdir, prepare_pack, &data);
 895
 896         report_pack_garbage(data.garbage);
 897         string_list_clear(data.garbage, 0);
 898 }
 899
 900 static void prepare_packed_git(struct repository *r);
 901 /*
 902  * Give a fast, rough count of the number of objects in the repository. This
 903  * ignores loose objects completely. If you have a lot of them, then either
 904  * you should repack because your performance will be awful, or they are
 905  * all unreachable objects about to be pruned, in which case they're not really
 906  * interesting as a measure of repo size in the first place.
 907  */
 908 unsigned long repo_approximate_object_count(struct repository *r)
 909 {
 910         if (!r->objects->approximate_object_count_valid) {
 911                 unsigned long count;
 912                 struct multi_pack_index *m;
 913                 struct packed_git *p;
 914
 915                 prepare_packed_git(r);
 916                 count = 0;
 917                 for (m = get_multi_pack_index(r); m; m = m->next)
 918                         count += m->num_objects;
 919                 for (p = r->objects->packed_git; p; p = p->next) {
 920                         if (open_pack_index(p))
 921                                 continue;
 922                         count += p->num_objects;
 923                 }
 924                 r->objects->approximate_object_count = count;
 925         }
 926         return r->objects->approximate_object_count;
 927 }
 928
 929 static void *get_next_packed_git(const void *p)
 930 {
 931         return ((const struct packed_git *)p)->next;
 932 }
 933
 934 static void set_next_packed_git(void *p, void *next)
 935 {
 936         ((struct packed_git *)p)->next = next;
 937 }
 938
 939 static int sort_pack(const void *a_, const void *b_)
 940 {
 941         const struct packed_git *a = a_;
 942         const struct packed_git *b = b_;
 943         int st;
 944
 945         /*
 946          * Local packs tend to contain objects specific to our
 947          * variant of the project than remote ones.  In addition,
 948          * remote ones could be on a network mounted filesystem.
 949          * Favor local ones for these reasons.
 950          */
 951         st = a->pack_local - b->pack_local;
 952         if (st)
 953                 return -st;
 954
 955         /*
 956          * Younger packs tend to contain more recent objects,
 957          * and more recent objects tend to get accessed more
 958          * often.
 959          */
 960         if (a->mtime < b->mtime)
 961                 return 1;
 962         else if (a->mtime == b->mtime)
 963                 return 0;
 964         return -1;
 965 }
 966
 967 static void rearrange_packed_git(struct repository *r)
 968 {
 969         r->objects->packed_git = llist_mergesort(
 970                 r->objects->packed_git, get_next_packed_git,
 971                 set_next_packed_git, sort_pack);
 972 }
 973
 974 static void prepare_packed_git_mru(struct repository *r)
 975 {
 976         struct packed_git *p;
 977
 978         INIT_LIST_HEAD(&r->objects->packed_git_mru);
 979
 980         for (p = r->objects->packed_git; p; p = p->next)
 981                 list_add_tail(&p->mru, &r->objects->packed_git_mru);
 982 }
 983
 984 static void prepare_packed_git(struct repository *r)
 985 {
 986         struct object_directory *odb;
 987
 988         if (r->objects->packed_git_initialized)
 989                 return;
 990
 991         prepare_alt_odb(r);
 992         for (odb = r->objects->odb; odb; odb = odb->next) {
 993                 int local = (odb == r->objects->odb);
 994                 prepare_multi_pack_index_one(r, odb->path, local);
 995                 prepare_packed_git_one(r, odb->path, local);
 996         }
 997         rearrange_packed_git(r);
 998
 999         prepare_packed_git_mru(r);
1000         r->objects->packed_git_initialized = 1;
1001 }
1002
1003 void reprepare_packed_git(struct repository *r)
1004 {
1005         struct object_directory *odb;
1006
1007         for (odb = r->objects->odb; odb; odb = odb->next)
1008                 odb_clear_loose_cache(odb);
1009
1010         r->objects->approximate_object_count_valid = 0;
1011         r->objects->packed_git_initialized = 0;
1012         prepare_packed_git(r);
1013 }
1014
1015 struct packed_git *get_packed_git(struct repository *r)
1016 {
1017         prepare_packed_git(r);
1018         return r->objects->packed_git;
1019 }
1020
1021 struct multi_pack_index *get_multi_pack_index(struct repository *r)
1022 {
1023         prepare_packed_git(r);
1024         return r->objects->multi_pack_index;
1025 }
1026
1027 struct packed_git *get_all_packs(struct repository *r)
1028 {
1029         struct multi_pack_index *m;
1030
1031         prepare_packed_git(r);
1032         for (m = r->objects->multi_pack_index; m; m = m->next) {
1033                 uint32_t i;
1034                 for (i = 0; i < m->num_packs; i++)
1035                         prepare_midx_pack(r, m, i);
1036         }
1037
1038         return r->objects->packed_git;
1039 }
1040
1041 struct list_head *get_packed_git_mru(struct repository *r)
1042 {
1043         prepare_packed_git(r);
1044         return &r->objects->packed_git_mru;
1045 }
1046
1047 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1048                 unsigned long len, enum object_type *type, unsigned long *sizep)
1049 {
1050         unsigned shift;
1051         unsigned long size, c;
1052         unsigned long used = 0;
1053
1054         c = buf[used++];
1055         *type = (c >> 4) & 7;
1056         size = c & 15;
1057         shift = 4;
1058         while (c & 0x80) {
1059                 if (len <= used || bitsizeof(long) <= shift) {
1060                         error("bad object header");
1061                         size = used = 0;
1062                         break;
1063                 }
1064                 c = buf[used++];
1065                 size += (c & 0x7f) << shift;
1066                 shift += 7;
1067         }
1068         *sizep = size;
1069         return used;
1070 }
1071
1072 unsigned long get_size_from_delta(struct packed_git *p,
1073                                   struct pack_window **w_curs,
1074                                   off_t curpos)
1075 {
1076         const unsigned char *data;
1077         unsigned char delta_head[20], *in;
1078         git_zstream stream;
1079         int st;
1080
1081         memset(&stream, 0, sizeof(stream));
1082         stream.next_out = delta_head;
1083         stream.avail_out = sizeof(delta_head);
1084
1085         git_inflate_init(&stream);
1086         do {
1087                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1088                 stream.next_in = in;
1089                 st = git_inflate(&stream, Z_FINISH);
1090                 curpos += stream.next_in - in;
1091         } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1092                  stream.total_out < sizeof(delta_head));
1093         git_inflate_end(&stream);
1094         if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1095                 error("delta data unpack-initial failed");
1096                 return 0;
1097         }
1098
1099         /* Examine the initial part of the delta to figure out
1100          * the result size.
1101          */
1102         data = delta_head;
1103
1104         /* ignore base size */
1105         get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1106
1107         /* Read the result size */
1108         return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1109 }
1110
1111 int unpack_object_header(struct packed_git *p,
1112                          struct pack_window **w_curs,
1113                          off_t *curpos,
1114                          unsigned long *sizep)
1115 {
1116         unsigned char *base;
1117         unsigned long left;
1118         unsigned long used;
1119         enum object_type type;
1120
1121         /* use_pack() assures us we have [base, base + 20) available
1122          * as a range that we can look at.  (Its actually the hash
1123          * size that is assured.)  With our object header encoding
1124          * the maximum deflated object size is 2^137, which is just
1125          * insane, so we know won't exceed what we have been given.
1126          */
1127         base = use_pack(p, w_curs, *curpos, &left);
1128         used = unpack_object_header_buffer(base, left, &type, sizep);
1129         if (!used) {
1130                 type = OBJ_BAD;
1131         } else
1132                 *curpos += used;
1133
1134         return type;
1135 }
1136
1137 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1138 {
1139         unsigned i;
1140         const unsigned hashsz = the_hash_algo->rawsz;
1141         for (i = 0; i < p->num_bad_objects; i++)
1142                 if (hasheq(sha1, p->bad_object_sha1 + hashsz * i))
1143                         return;
1144         p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1145                                       st_mult(GIT_MAX_RAWSZ,
1146                                               st_add(p->num_bad_objects, 1)));
1147         hashcpy(p->bad_object_sha1 + hashsz * p->num_bad_objects, sha1);
1148         p->num_bad_objects++;
1149 }
1150
1151 const struct packed_git *has_packed_and_bad(struct repository *r,
1152                                             const unsigned char *sha1)
1153 {
1154         struct packed_git *p;
1155         unsigned i;
1156
1157         for (p = r->objects->packed_git; p; p = p->next)
1158                 for (i = 0; i < p->num_bad_objects; i++)
1159                         if (hasheq(sha1,
1160                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1161                                 return p;
1162         return NULL;
1163 }
1164
1165 off_t get_delta_base(struct packed_git *p,
1166                      struct pack_window **w_curs,
1167                      off_t *curpos,
1168                      enum object_type type,
1169                      off_t delta_obj_offset)
1170 {
1171         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1172         off_t base_offset;
1173
1174         /* use_pack() assured us we have [base_info, base_info + 20)
1175          * as a range that we can look at without walking off the
1176          * end of the mapped window.  Its actually the hash size
1177          * that is assured.  An OFS_DELTA longer than the hash size
1178          * is stupid, as then a REF_DELTA would be smaller to store.
1179          */
1180         if (type == OBJ_OFS_DELTA) {
1181                 unsigned used = 0;
1182                 unsigned char c = base_info[used++];
1183                 base_offset = c & 127;
1184                 while (c & 128) {
1185                         base_offset += 1;
1186                         if (!base_offset || MSB(base_offset, 7))
1187                                 return 0;  /* overflow */
1188                         c = base_info[used++];
1189                         base_offset = (base_offset << 7) + (c & 127);
1190                 }
1191                 base_offset = delta_obj_offset - base_offset;
1192                 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1193                         return 0;  /* out of bound */
1194                 *curpos += used;
1195         } else if (type == OBJ_REF_DELTA) {
1196                 /* The base entry _must_ be in the same pack */
1197                 base_offset = find_pack_entry_one(base_info, p);
1198                 *curpos += the_hash_algo->rawsz;
1199         } else
1200                 die("I am totally screwed");
1201         return base_offset;
1202 }
1203
1204 /*
1205  * Like get_delta_base above, but we return the sha1 instead of the pack
1206  * offset. This means it is cheaper for REF deltas (we do not have to do
1207  * the final object lookup), but more expensive for OFS deltas (we
1208  * have to load the revidx to convert the offset back into a sha1).
1209  */
1210 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1211                                                 struct pack_window **w_curs,
1212                                                 off_t curpos,
1213                                                 enum object_type type,
1214                                                 off_t delta_obj_offset)
1215 {
1216         if (type == OBJ_REF_DELTA) {
1217                 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1218                 return base;
1219         } else if (type == OBJ_OFS_DELTA) {
1220                 struct revindex_entry *revidx;
1221                 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1222                                                    type, delta_obj_offset);
1223
1224                 if (!base_offset)
1225                         return NULL;
1226
1227                 revidx = find_pack_revindex(p, base_offset);
1228                 if (!revidx)
1229                         return NULL;
1230
1231                 return nth_packed_object_sha1(p, revidx->nr);
1232         } else
1233                 return NULL;
1234 }
1235
1236 static int retry_bad_packed_offset(struct repository *r,
1237                                    struct packed_git *p,
1238                                    off_t obj_offset)
1239 {
1240         int type;
1241         struct revindex_entry *revidx;
1242         struct object_id oid;
1243         revidx = find_pack_revindex(p, obj_offset);
1244         if (!revidx)
1245                 return OBJ_BAD;
1246         nth_packed_object_oid(&oid, p, revidx->nr);
1247         mark_bad_packed_object(p, oid.hash);
1248         type = oid_object_info(r, &oid, NULL);
1249         if (type <= OBJ_NONE)
1250                 return OBJ_BAD;
1251         return type;
1252 }
1253
1254 #define POI_STACK_PREALLOC 64
1255
1256 static enum object_type packed_to_object_type(struct repository *r,
1257                                               struct packed_git *p,
1258                                               off_t obj_offset,
1259                                               enum object_type type,
1260                                               struct pack_window **w_curs,
1261                                               off_t curpos)
1262 {
1263         off_t small_poi_stack[POI_STACK_PREALLOC];
1264         off_t *poi_stack = small_poi_stack;
1265         int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1266
1267         while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1268                 off_t base_offset;
1269                 unsigned long size;
1270                 /* Push the object we're going to leave behind */
1271                 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1272                         poi_stack_alloc = alloc_nr(poi_stack_nr);
1273                         ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1274                         COPY_ARRAY(poi_stack, small_poi_stack, poi_stack_nr);
1275                 } else {
1276                         ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1277                 }
1278                 poi_stack[poi_stack_nr++] = obj_offset;
1279                 /* If parsing the base offset fails, just unwind */
1280                 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1281                 if (!base_offset)
1282                         goto unwind;
1283                 curpos = obj_offset = base_offset;
1284                 type = unpack_object_header(p, w_curs, &curpos, &size);
1285                 if (type <= OBJ_NONE) {
1286                         /* If getting the base itself fails, we first
1287                          * retry the base, otherwise unwind */
1288                         type = retry_bad_packed_offset(r, p, base_offset);
1289                         if (type > OBJ_NONE)
1290                                 goto out;
1291                         goto unwind;
1292                 }
1293         }
1294
1295         switch (type) {
1296         case OBJ_BAD:
1297         case OBJ_COMMIT:
1298         case OBJ_TREE:
1299         case OBJ_BLOB:
1300         case OBJ_TAG:
1301                 break;
1302         default:
1303                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1304                       type, (uintmax_t)obj_offset, p->pack_name);
1305                 type = OBJ_BAD;
1306         }
1307
1308 out:
1309         if (poi_stack != small_poi_stack)
1310                 free(poi_stack);
1311         return type;
1312
1313 unwind:
1314         while (poi_stack_nr) {
1315                 obj_offset = poi_stack[--poi_stack_nr];
1316                 type = retry_bad_packed_offset(r, p, obj_offset);
1317                 if (type > OBJ_NONE)
1318                         goto out;
1319         }
1320         type = OBJ_BAD;
1321         goto out;
1322 }
1323
1324 static struct hashmap delta_base_cache;
1325 static size_t delta_base_cached;
1326
1327 static LIST_HEAD(delta_base_cache_lru);
1328
1329 struct delta_base_cache_key {
1330         struct packed_git *p;
1331         off_t base_offset;
1332 };
1333
1334 struct delta_base_cache_entry {
1335         struct hashmap_entry ent;
1336         struct delta_base_cache_key key;
1337         struct list_head lru;
1338         void *data;
1339         unsigned long size;
1340         enum object_type type;
1341 };
1342
1343 static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1344 {
1345         unsigned int hash;
1346
1347         hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1348         hash += (hash >> 8) + (hash >> 16);
1349         return hash;
1350 }
1351
1352 static struct delta_base_cache_entry *
1353 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1354 {
1355         struct hashmap_entry entry, *e;
1356         struct delta_base_cache_key key;
1357
1358         if (!delta_base_cache.cmpfn)
1359                 return NULL;
1360
1361         hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1362         key.p = p;
1363         key.base_offset = base_offset;
1364         e = hashmap_get(&delta_base_cache, &entry, &key);
1365         return e ? container_of(e, struct delta_base_cache_entry, ent) : NULL;
1366 }
1367
1368 static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
1369                                    const struct delta_base_cache_key *b)
1370 {
1371         return a->p == b->p && a->base_offset == b->base_offset;
1372 }
1373
1374 static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
1375                                      const struct hashmap_entry *va,
1376                                      const struct hashmap_entry *vb,
1377                                      const void *vkey)
1378 {
1379         const struct delta_base_cache_entry *a, *b;
1380         const struct delta_base_cache_key *key = vkey;
1381
1382         a = container_of(va, const struct delta_base_cache_entry, ent);
1383         b = container_of(vb, const struct delta_base_cache_entry, ent);
1384
1385         if (key)
1386                 return !delta_base_cache_key_eq(&a->key, key);
1387         else
1388                 return !delta_base_cache_key_eq(&a->key, &b->key);
1389 }
1390
1391 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1392 {
1393         return !!get_delta_base_cache_entry(p, base_offset);
1394 }
1395
1396 /*
1397  * Remove the entry from the cache, but do _not_ free the associated
1398  * entry data. The caller takes ownership of the "data" buffer, and
1399  * should copy out any fields it wants before detaching.
1400  */
1401 static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1402 {
1403         hashmap_remove(&delta_base_cache, &ent->ent, &ent->key);
1404         list_del(&ent->lru);
1405         delta_base_cached -= ent->size;
1406         free(ent);
1407 }
1408
1409 static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
1410                                    off_t base_offset, unsigned long *base_size,
1411                                    enum object_type *type)
1412 {
1413         struct delta_base_cache_entry *ent;
1414
1415         ent = get_delta_base_cache_entry(p, base_offset);
1416         if (!ent)
1417                 return unpack_entry(r, p, base_offset, type, base_size);
1418
1419         if (type)
1420                 *type = ent->type;
1421         if (base_size)
1422                 *base_size = ent->size;
1423         return xmemdupz(ent->data, ent->size);
1424 }
1425
1426 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1427 {
1428         free(ent->data);
1429         detach_delta_base_cache_entry(ent);
1430 }
1431
1432 void clear_delta_base_cache(void)
1433 {
1434         struct list_head *lru, *tmp;
1435         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1436                 struct delta_base_cache_entry *entry =
1437                         list_entry(lru, struct delta_base_cache_entry, lru);
1438                 release_delta_base_cache(entry);
1439         }
1440 }
1441
1442 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1443         void *base, unsigned long base_size, enum object_type type)
1444 {
1445         struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1446         struct list_head *lru, *tmp;
1447
1448         delta_base_cached += base_size;
1449
1450         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1451                 struct delta_base_cache_entry *f =
1452                         list_entry(lru, struct delta_base_cache_entry, lru);
1453                 if (delta_base_cached <= delta_base_cache_limit)
1454                         break;
1455                 release_delta_base_cache(f);
1456         }
1457
1458         ent->key.p = p;
1459         ent->key.base_offset = base_offset;
1460         ent->type = type;
1461         ent->data = base;
1462         ent->size = base_size;
1463         list_add_tail(&ent->lru, &delta_base_cache_lru);
1464
1465         if (!delta_base_cache.cmpfn)
1466                 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1467         hashmap_entry_init(&ent->ent, pack_entry_hash(p, base_offset));
1468         hashmap_add(&delta_base_cache, &ent->ent);
1469 }
1470
1471 int packed_object_info(struct repository *r, struct packed_git *p,
1472                        off_t obj_offset, struct object_info *oi)
1473 {
1474         struct pack_window *w_curs = NULL;
1475         unsigned long size;
1476         off_t curpos = obj_offset;
1477         enum object_type type;
1478
1479         /*
1480          * We always get the representation type, but only convert it to
1481          * a "real" type later if the caller is interested.
1482          */
1483         if (oi->contentp) {
1484                 *oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
1485                                                       &type);
1486                 if (!*oi->contentp)
1487                         type = OBJ_BAD;
1488         } else {
1489                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1490         }
1491
1492         if (!oi->contentp && oi->sizep) {
1493                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1494                         off_t tmp_pos = curpos;
1495                         off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1496                                                            type, obj_offset);
1497                         if (!base_offset) {
1498                                 type = OBJ_BAD;
1499                                 goto out;
1500                         }
1501                         *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1502                         if (*oi->sizep == 0) {
1503                                 type = OBJ_BAD;
1504                                 goto out;
1505                         }
1506                 } else {
1507                         *oi->sizep = size;
1508                 }
1509         }
1510
1511         if (oi->disk_sizep) {
1512                 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1513                 *oi->disk_sizep = revidx[1].offset - obj_offset;
1514         }
1515
1516         if (oi->typep || oi->type_name) {
1517                 enum object_type ptot;
1518                 ptot = packed_to_object_type(r, p, obj_offset,
1519                                              type, &w_curs, curpos);
1520                 if (oi->typep)
1521                         *oi->typep = ptot;
1522                 if (oi->type_name) {
1523                         const char *tn = type_name(ptot);
1524                         if (tn)
1525                                 strbuf_addstr(oi->type_name, tn);
1526                 }
1527                 if (ptot < 0) {
1528                         type = OBJ_BAD;
1529                         goto out;
1530                 }
1531         }
1532
1533         if (oi->delta_base_sha1) {
1534                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1535                         const unsigned char *base;
1536
1537                         base = get_delta_base_sha1(p, &w_curs, curpos,
1538                                                    type, obj_offset);
1539                         if (!base) {
1540                                 type = OBJ_BAD;
1541                                 goto out;
1542                         }
1543
1544                         hashcpy(oi->delta_base_sha1, base);
1545                 } else
1546                         hashclr(oi->delta_base_sha1);
1547         }
1548
1549         oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1550                                                           OI_PACKED;
1551
1552 out:
1553         unuse_pack(&w_curs);
1554         return type;
1555 }
1556
1557 static void *unpack_compressed_entry(struct packed_git *p,
1558                                     struct pack_window **w_curs,
1559                                     off_t curpos,
1560                                     unsigned long size)
1561 {
1562         int st;
1563         git_zstream stream;
1564         unsigned char *buffer, *in;
1565
1566         buffer = xmallocz_gently(size);
1567         if (!buffer)
1568                 return NULL;
1569         memset(&stream, 0, sizeof(stream));
1570         stream.next_out = buffer;
1571         stream.avail_out = size + 1;
1572
1573         git_inflate_init(&stream);
1574         do {
1575                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1576                 stream.next_in = in;
1577                 st = git_inflate(&stream, Z_FINISH);
1578                 if (!stream.avail_out)
1579                         break; /* the payload is larger than it should be */
1580                 curpos += stream.next_in - in;
1581         } while (st == Z_OK || st == Z_BUF_ERROR);
1582         git_inflate_end(&stream);
1583         if ((st != Z_STREAM_END) || stream.total_out != size) {
1584                 free(buffer);
1585                 return NULL;
1586         }
1587
1588         /* versions of zlib can clobber unconsumed portion of outbuf */
1589         buffer[size] = '\0';
1590
1591         return buffer;
1592 }
1593
1594 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1595 {
1596         static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1597         trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1598                          p->pack_name, (uintmax_t)obj_offset);
1599 }
1600
1601 int do_check_packed_object_crc;
1602
1603 #define UNPACK_ENTRY_STACK_PREALLOC 64
1604 struct unpack_entry_stack_ent {
1605         off_t obj_offset;
1606         off_t curpos;
1607         unsigned long size;
1608 };
1609
1610 static void *read_object(struct repository *r,
1611                          const struct object_id *oid,
1612                          enum object_type *type,
1613                          unsigned long *size)
1614 {
1615         struct object_info oi = OBJECT_INFO_INIT;
1616         void *content;
1617         oi.typep = type;
1618         oi.sizep = size;
1619         oi.contentp = &content;
1620
1621         if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1622                 return NULL;
1623         return content;
1624 }
1625
1626 void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
1627                    enum object_type *final_type, unsigned long *final_size)
1628 {
1629         struct pack_window *w_curs = NULL;
1630         off_t curpos = obj_offset;
1631         void *data = NULL;
1632         unsigned long size;
1633         enum object_type type;
1634         struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1635         struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1636         int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1637         int base_from_cache = 0;
1638
1639         write_pack_access_log(p, obj_offset);
1640
1641         /* PHASE 1: drill down to the innermost base object */
1642         for (;;) {
1643                 off_t base_offset;
1644                 int i;
1645                 struct delta_base_cache_entry *ent;
1646
1647                 ent = get_delta_base_cache_entry(p, curpos);
1648                 if (ent) {
1649                         type = ent->type;
1650                         data = ent->data;
1651                         size = ent->size;
1652                         detach_delta_base_cache_entry(ent);
1653                         base_from_cache = 1;
1654                         break;
1655                 }
1656
1657                 if (do_check_packed_object_crc && p->index_version > 1) {
1658                         struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1659                         off_t len = revidx[1].offset - obj_offset;
1660                         if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1661                                 struct object_id oid;
1662                                 nth_packed_object_oid(&oid, p, revidx->nr);
1663                                 error("bad packed object CRC for %s",
1664                                       oid_to_hex(&oid));
1665                                 mark_bad_packed_object(p, oid.hash);
1666                                 data = NULL;
1667                                 goto out;
1668                         }
1669                 }
1670
1671                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1672                 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1673                         break;
1674
1675                 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1676                 if (!base_offset) {
1677                         error("failed to validate delta base reference "
1678                               "at offset %"PRIuMAX" from %s",
1679                               (uintmax_t)curpos, p->pack_name);
1680                         /* bail to phase 2, in hopes of recovery */
1681                         data = NULL;
1682                         break;
1683                 }
1684
1685                 /* push object, proceed to base */
1686                 if (delta_stack_nr >= delta_stack_alloc
1687                     && delta_stack == small_delta_stack) {
1688                         delta_stack_alloc = alloc_nr(delta_stack_nr);
1689                         ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1690                         COPY_ARRAY(delta_stack, small_delta_stack,
1691                                    delta_stack_nr);
1692                 } else {
1693                         ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1694                 }
1695                 i = delta_stack_nr++;
1696                 delta_stack[i].obj_offset = obj_offset;
1697                 delta_stack[i].curpos = curpos;
1698                 delta_stack[i].size = size;
1699
1700                 curpos = obj_offset = base_offset;
1701         }
1702
1703         /* PHASE 2: handle the base */
1704         switch (type) {
1705         case OBJ_OFS_DELTA:
1706         case OBJ_REF_DELTA:
1707                 if (data)
1708                         BUG("unpack_entry: left loop at a valid delta");
1709                 break;
1710         case OBJ_COMMIT:
1711         case OBJ_TREE:
1712         case OBJ_BLOB:
1713         case OBJ_TAG:
1714                 if (!base_from_cache)
1715                         data = unpack_compressed_entry(p, &w_curs, curpos, size);
1716                 break;
1717         default:
1718                 data = NULL;
1719                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1720                       type, (uintmax_t)obj_offset, p->pack_name);
1721         }
1722
1723         /* PHASE 3: apply deltas in order */
1724
1725         /* invariants:
1726          *   'data' holds the base data, or NULL if there was corruption
1727          */
1728         while (delta_stack_nr) {
1729                 void *delta_data;
1730                 void *base = data;
1731                 void *external_base = NULL;
1732                 unsigned long delta_size, base_size = size;
1733                 int i;
1734
1735                 data = NULL;
1736
1737                 if (base)
1738                         add_delta_base_cache(p, obj_offset, base, base_size, type);
1739
1740                 if (!base) {
1741                         /*
1742                          * We're probably in deep shit, but let's try to fetch
1743                          * the required base anyway from another pack or loose.
1744                          * This is costly but should happen only in the presence
1745                          * of a corrupted pack, and is better than failing outright.
1746                          */
1747                         struct revindex_entry *revidx;
1748                         struct object_id base_oid;
1749                         revidx = find_pack_revindex(p, obj_offset);
1750                         if (revidx) {
1751                                 nth_packed_object_oid(&base_oid, p, revidx->nr);
1752                                 error("failed to read delta base object %s"
1753                                       " at offset %"PRIuMAX" from %s",
1754                                       oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1755                                       p->pack_name);
1756                                 mark_bad_packed_object(p, base_oid.hash);
1757                                 base = read_object(r, &base_oid, &type, &base_size);
1758                                 external_base = base;
1759                         }
1760                 }
1761
1762                 i = --delta_stack_nr;
1763                 obj_offset = delta_stack[i].obj_offset;
1764                 curpos = delta_stack[i].curpos;
1765                 delta_size = delta_stack[i].size;
1766
1767                 if (!base)
1768                         continue;
1769
1770                 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1771
1772                 if (!delta_data) {
1773                         error("failed to unpack compressed delta "
1774                               "at offset %"PRIuMAX" from %s",
1775                               (uintmax_t)curpos, p->pack_name);
1776                         data = NULL;
1777                         free(external_base);
1778                         continue;
1779                 }
1780
1781                 data = patch_delta(base, base_size,
1782                                    delta_data, delta_size,
1783                                    &size);
1784
1785                 /*
1786                  * We could not apply the delta; warn the user, but keep going.
1787                  * Our failure will be noticed either in the next iteration of
1788                  * the loop, or if this is the final delta, in the caller when
1789                  * we return NULL. Those code paths will take care of making
1790                  * a more explicit warning and retrying with another copy of
1791                  * the object.
1792                  */
1793                 if (!data)
1794                         error("failed to apply delta");
1795
1796                 free(delta_data);
1797                 free(external_base);
1798         }
1799
1800         if (final_type)
1801                 *final_type = type;
1802         if (final_size)
1803                 *final_size = size;
1804
1805 out:
1806         unuse_pack(&w_curs);
1807
1808         if (delta_stack != small_delta_stack)
1809                 free(delta_stack);
1810
1811         return data;
1812 }
1813
1814 int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1815 {
1816         const unsigned char *index_fanout = p->index_data;
1817         const unsigned char *index_lookup;
1818         const unsigned int hashsz = the_hash_algo->rawsz;
1819         int index_lookup_width;
1820
1821         if (!index_fanout)
1822                 BUG("bsearch_pack called without a valid pack-index");
1823
1824         index_lookup = index_fanout + 4 * 256;
1825         if (p->index_version == 1) {
1826                 index_lookup_width = hashsz + 4;
1827                 index_lookup += 4;
1828         } else {
1829                 index_lookup_width = hashsz;
1830                 index_fanout += 8;
1831                 index_lookup += 8;
1832         }
1833
1834         return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1835                             index_lookup, index_lookup_width, result);
1836 }
1837
1838 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1839                                             uint32_t n)
1840 {
1841         const unsigned char *index = p->index_data;
1842         const unsigned int hashsz = the_hash_algo->rawsz;
1843         if (!index) {
1844                 if (open_pack_index(p))
1845                         return NULL;
1846                 index = p->index_data;
1847         }
1848         if (n >= p->num_objects)
1849                 return NULL;
1850         index += 4 * 256;
1851         if (p->index_version == 1) {
1852                 return index + (hashsz + 4) * n + 4;
1853         } else {
1854                 index += 8;
1855                 return index + hashsz * n;
1856         }
1857 }
1858
1859 const struct object_id *nth_packed_object_oid(struct object_id *oid,
1860                                               struct packed_git *p,
1861                                               uint32_t n)
1862 {
1863         const unsigned char *hash = nth_packed_object_sha1(p, n);
1864         if (!hash)
1865                 return NULL;
1866         hashcpy(oid->hash, hash);
1867         return oid;
1868 }
1869
1870 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1871 {
1872         const unsigned char *ptr = vptr;
1873         const unsigned char *start = p->index_data;
1874         const unsigned char *end = start + p->index_size;
1875         if (ptr < start)
1876                 die(_("offset before start of pack index for %s (corrupt index?)"),
1877                     p->pack_name);
1878         /* No need to check for underflow; .idx files must be at least 8 bytes */
1879         if (ptr >= end - 8)
1880                 die(_("offset beyond end of pack index for %s (truncated index?)"),
1881                     p->pack_name);
1882 }
1883
1884 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1885 {
1886         const unsigned char *index = p->index_data;
1887         const unsigned int hashsz = the_hash_algo->rawsz;
1888         index += 4 * 256;
1889         if (p->index_version == 1) {
1890                 return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
1891         } else {
1892                 uint32_t off;
1893                 index += 8 + p->num_objects * (hashsz + 4);
1894                 off = ntohl(*((uint32_t *)(index + 4 * n)));
1895                 if (!(off & 0x80000000))
1896                         return off;
1897                 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1898                 check_pack_index_ptr(p, index);
1899                 return get_be64(index);
1900         }
1901 }
1902
1903 off_t find_pack_entry_one(const unsigned char *sha1,
1904                                   struct packed_git *p)
1905 {
1906         const unsigned char *index = p->index_data;
1907         struct object_id oid;
1908         uint32_t result;
1909
1910         if (!index) {
1911                 if (open_pack_index(p))
1912                         return 0;
1913         }
1914
1915         hashcpy(oid.hash, sha1);
1916         if (bsearch_pack(&oid, p, &result))
1917                 return nth_packed_object_offset(p, result);
1918         return 0;
1919 }
1920
1921 int is_pack_valid(struct packed_git *p)
1922 {
1923         /* An already open pack is known to be valid. */
1924         if (p->pack_fd != -1)
1925                 return 1;
1926
1927         /* If the pack has one window completely covering the
1928          * file size, the pack is known to be valid even if
1929          * the descriptor is not currently open.
1930          */
1931         if (p->windows) {
1932                 struct pack_window *w = p->windows;
1933
1934                 if (!w->offset && w->len == p->pack_size)
1935                         return 1;
1936         }
1937
1938         /* Force the pack to open to prove its valid. */
1939         return !open_packed_git(p);
1940 }
1941
1942 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1943                                   struct packed_git *packs)
1944 {
1945         struct packed_git *p;
1946
1947         for (p = packs; p; p = p->next) {
1948                 if (find_pack_entry_one(sha1, p))
1949                         return p;
1950         }
1951         return NULL;
1952
1953 }
1954
1955 static int fill_pack_entry(const struct object_id *oid,
1956                            struct pack_entry *e,
1957                            struct packed_git *p)
1958 {
1959         off_t offset;
1960
1961         if (p->num_bad_objects) {
1962                 unsigned i;
1963                 for (i = 0; i < p->num_bad_objects; i++)
1964                         if (hasheq(oid->hash,
1965                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1966                                 return 0;
1967         }
1968
1969         offset = find_pack_entry_one(oid->hash, p);
1970         if (!offset)
1971                 return 0;
1972
1973         /*
1974          * We are about to tell the caller where they can locate the
1975          * requested object.  We better make sure the packfile is
1976          * still here and can be accessed before supplying that
1977          * answer, as it may have been deleted since the index was
1978          * loaded!
1979          */
1980         if (!is_pack_valid(p))
1981                 return 0;
1982         e->offset = offset;
1983         e->p = p;
1984         return 1;
1985 }
1986
1987 int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
1988 {
1989         struct list_head *pos;
1990         struct multi_pack_index *m;
1991
1992         prepare_packed_git(r);
1993         if (!r->objects->packed_git && !r->objects->multi_pack_index)
1994                 return 0;
1995
1996         for (m = r->objects->multi_pack_index; m; m = m->next) {
1997                 if (fill_midx_entry(r, oid, e, m))
1998                         return 1;
1999         }
2000
2001         list_for_each(pos, &r->objects->packed_git_mru) {
2002                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
2003                 if (!p->multi_pack_index && fill_pack_entry(oid, e, p)) {
2004                         list_move(&p->mru, &r->objects->packed_git_mru);
2005                         return 1;
2006                 }
2007         }
2008         return 0;
2009 }
2010
2011 int has_object_pack(const struct object_id *oid)
2012 {
2013         struct pack_entry e;
2014         return find_pack_entry(the_repository, oid, &e);
2015 }
2016
2017 int has_pack_index(const unsigned char *sha1)
2018 {
2019         struct stat st;
2020         if (stat(sha1_pack_index_name(sha1), &st))
2021                 return 0;
2022         return 1;
2023 }
2024
2025 int for_each_object_in_pack(struct packed_git *p,
2026                             each_packed_object_fn cb, void *data,
2027                             enum for_each_object_flags flags)
2028 {
2029         uint32_t i;
2030         int r = 0;
2031
2032         if (flags & FOR_EACH_OBJECT_PACK_ORDER) {
2033                 if (load_pack_revindex(p))
2034                         return -1;
2035         }
2036
2037         for (i = 0; i < p->num_objects; i++) {
2038                 uint32_t pos;
2039                 struct object_id oid;
2040
2041                 if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2042                         pos = p->revindex[i].nr;
2043                 else
2044                         pos = i;
2045
2046                 if (!nth_packed_object_oid(&oid, p, pos))
2047                         return error("unable to get sha1 of object %u in %s",
2048                                      pos, p->pack_name);
2049
2050                 r = cb(&oid, p, pos, data);
2051                 if (r)
2052                         break;
2053         }
2054         return r;
2055 }
2056
2057 int for_each_packed_object(each_packed_object_fn cb, void *data,
2058                            enum for_each_object_flags flags)
2059 {
2060         struct packed_git *p;
2061         int r = 0;
2062         int pack_errors = 0;
2063
2064         prepare_packed_git(the_repository);
2065         for (p = get_all_packs(the_repository); p; p = p->next) {
2066                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2067                         continue;
2068                 if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
2069                     !p->pack_promisor)
2070                         continue;
2071                 if (open_pack_index(p)) {
2072                         pack_errors = 1;
2073                         continue;
2074                 }
2075                 r = for_each_object_in_pack(p, cb, data, flags);
2076                 if (r)
2077                         break;
2078         }
2079         return r ? r : pack_errors;
2080 }
2081
2082 static int add_promisor_object(const struct object_id *oid,
2083                                struct packed_git *pack,
2084                                uint32_t pos,
2085                                void *set_)
2086 {
2087         struct oidset *set = set_;
2088         struct object *obj = parse_object(the_repository, oid);
2089         if (!obj)
2090                 return 1;
2091
2092         oidset_insert(set, oid);
2093
2094         /*
2095          * If this is a tree, commit, or tag, the objects it refers
2096          * to are also promisor objects. (Blobs refer to no objects->)
2097          */
2098         if (obj->type == OBJ_TREE) {
2099                 struct tree *tree = (struct tree *)obj;
2100                 struct tree_desc desc;
2101                 struct name_entry entry;
2102                 if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
2103                         /*
2104                          * Error messages are given when packs are
2105                          * verified, so do not print any here.
2106                          */
2107                         return 0;
2108                 while (tree_entry_gently(&desc, &entry))
2109                         oidset_insert(set, &entry.oid);
2110         } else if (obj->type == OBJ_COMMIT) {
2111                 struct commit *commit = (struct commit *) obj;
2112                 struct commit_list *parents = commit->parents;
2113
2114                 oidset_insert(set, get_commit_tree_oid(commit));
2115                 for (; parents; parents = parents->next)
2116                         oidset_insert(set, &parents->item->object.oid);
2117         } else if (obj->type == OBJ_TAG) {
2118                 struct tag *tag = (struct tag *) obj;
2119                 oidset_insert(set, get_tagged_oid(tag));
2120         }
2121         return 0;
2122 }
2123
2124 int is_promisor_object(const struct object_id *oid)
2125 {
2126         static struct oidset promisor_objects;
2127         static int promisor_objects_prepared;
2128
2129         if (!promisor_objects_prepared) {
2130                 if (has_promisor_remote()) {
2131                         for_each_packed_object(add_promisor_object,
2132                                                &promisor_objects,
2133                                                FOR_EACH_OBJECT_PROMISOR_ONLY);
2134                 }
2135                 promisor_objects_prepared = 1;
2136         }
2137         return oidset_contains(&promisor_objects, oid);
2138 }