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 "list.h"
  10 #include "streaming.h"
  11 #include "sha1-lookup.h"
  12 #include "commit.h"
  13 #include "object.h"
  14 #include "tag.h"
  15 #include "tree-walk.h"
  16 #include "tree.h"
  17 #include "object-store.h"
  18 #include "midx.h"
  19 #include "commit-graph.h"
  20
  21 char *odb_pack_name(struct strbuf *buf,
  22                     const unsigned char *sha1,
  23                     const char *ext)
  24 {
  25         strbuf_reset(buf);
  26         strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
  27                     sha1_to_hex(sha1), 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 release_pack_memory(size_t need)
 291 {
 292         size_t cur = pack_mapped;
 293         while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 294                 ; /* nothing */
 295 }
 296
 297 void close_pack_windows(struct packed_git *p)
 298 {
 299         while (p->windows) {
 300                 struct pack_window *w = p->windows;
 301
 302                 if (w->inuse_cnt)
 303                         die("pack '%s' still has open windows to it",
 304                             p->pack_name);
 305                 munmap(w->base, w->len);
 306                 pack_mapped -= w->len;
 307                 pack_open_windows--;
 308                 p->windows = w->next;
 309                 free(w);
 310         }
 311 }
 312
 313 int close_pack_fd(struct packed_git *p)
 314 {
 315         if (p->pack_fd < 0)
 316                 return 0;
 317
 318         close(p->pack_fd);
 319         pack_open_fds--;
 320         p->pack_fd = -1;
 321
 322         return 1;
 323 }
 324
 325 void close_pack_index(struct packed_git *p)
 326 {
 327         if (p->index_data) {
 328                 munmap((void *)p->index_data, p->index_size);
 329                 p->index_data = NULL;
 330         }
 331 }
 332
 333 void close_pack(struct packed_git *p)
 334 {
 335         close_pack_windows(p);
 336         close_pack_fd(p);
 337         close_pack_index(p);
 338 }
 339
 340 void close_object_store(struct raw_object_store *o)
 341 {
 342         struct packed_git *p;
 343
 344         for (p = o->packed_git; p; p = p->next)
 345                 if (p->do_not_close)
 346                         BUG("want to close pack marked 'do-not-close'");
 347                 else
 348                         close_pack(p);
 349
 350         if (o->multi_pack_index) {
 351                 close_midx(o->multi_pack_index);
 352                 o->multi_pack_index = NULL;
 353         }
 354
 355         close_commit_graph(o);
 356 }
 357
 358 /*
 359  * The LRU pack is the one with the oldest MRU window, preferring packs
 360  * with no used windows, or the oldest mtime if it has no windows allocated.
 361  */
 362 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 363 {
 364         struct pack_window *w, *this_mru_w;
 365         int has_windows_inuse = 0;
 366
 367         /*
 368          * Reject this pack if it has windows and the previously selected
 369          * one does not.  If this pack does not have windows, reject
 370          * it if the pack file is newer than the previously selected one.
 371          */
 372         if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 373                 return;
 374
 375         for (w = this_mru_w = p->windows; w; w = w->next) {
 376                 /*
 377                  * Reject this pack if any of its windows are in use,
 378                  * but the previously selected pack did not have any
 379                  * inuse windows.  Otherwise, record that this pack
 380                  * has windows in use.
 381                  */
 382                 if (w->inuse_cnt) {
 383                         if (*accept_windows_inuse)
 384                                 has_windows_inuse = 1;
 385                         else
 386                                 return;
 387                 }
 388
 389                 if (w->last_used > this_mru_w->last_used)
 390                         this_mru_w = w;
 391
 392                 /*
 393                  * Reject this pack if it has windows that have been
 394                  * used more recently than the previously selected pack.
 395                  * If the previously selected pack had windows inuse and
 396                  * we have not encountered a window in this pack that is
 397                  * inuse, skip this check since we prefer a pack with no
 398                  * inuse windows to one that has inuse windows.
 399                  */
 400                 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 401                     this_mru_w->last_used > (*mru_w)->last_used)
 402                         return;
 403         }
 404
 405         /*
 406          * Select this pack.
 407          */
 408         *mru_w = this_mru_w;
 409         *lru_p = p;
 410         *accept_windows_inuse = has_windows_inuse;
 411 }
 412
 413 static int close_one_pack(void)
 414 {
 415         struct packed_git *p, *lru_p = NULL;
 416         struct pack_window *mru_w = NULL;
 417         int accept_windows_inuse = 1;
 418
 419         for (p = the_repository->objects->packed_git; p; p = p->next) {
 420                 if (p->pack_fd == -1)
 421                         continue;
 422                 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 423         }
 424
 425         if (lru_p)
 426                 return close_pack_fd(lru_p);
 427
 428         return 0;
 429 }
 430
 431 static unsigned int get_max_fd_limit(void)
 432 {
 433 #ifdef RLIMIT_NOFILE
 434         {
 435                 struct rlimit lim;
 436
 437                 if (!getrlimit(RLIMIT_NOFILE, &lim))
 438                         return lim.rlim_cur;
 439         }
 440 #endif
 441
 442 #ifdef _SC_OPEN_MAX
 443         {
 444                 long open_max = sysconf(_SC_OPEN_MAX);
 445                 if (0 < open_max)
 446                         return open_max;
 447                 /*
 448                  * Otherwise, we got -1 for one of the two
 449                  * reasons:
 450                  *
 451                  * (1) sysconf() did not understand _SC_OPEN_MAX
 452                  *     and signaled an error with -1; or
 453                  * (2) sysconf() said there is no limit.
 454                  *
 455                  * We _could_ clear errno before calling sysconf() to
 456                  * tell these two cases apart and return a huge number
 457                  * in the latter case to let the caller cap it to a
 458                  * value that is not so selfish, but letting the
 459                  * fallback OPEN_MAX codepath take care of these cases
 460                  * is a lot simpler.
 461                  */
 462         }
 463 #endif
 464
 465 #ifdef OPEN_MAX
 466         return OPEN_MAX;
 467 #else
 468         return 1; /* see the caller ;-) */
 469 #endif
 470 }
 471
 472 const char *pack_basename(struct packed_git *p)
 473 {
 474         const char *ret = strrchr(p->pack_name, '/');
 475         if (ret)
 476                 ret = ret + 1; /* skip past slash */
 477         else
 478                 ret = p->pack_name; /* we only have a base */
 479         return ret;
 480 }
 481
 482 /*
 483  * Do not call this directly as this leaks p->pack_fd on error return;
 484  * call open_packed_git() instead.
 485  */
 486 static int open_packed_git_1(struct packed_git *p)
 487 {
 488         struct stat st;
 489         struct pack_header hdr;
 490         unsigned char hash[GIT_MAX_RAWSZ];
 491         unsigned char *idx_hash;
 492         long fd_flag;
 493         ssize_t read_result;
 494         const unsigned hashsz = the_hash_algo->rawsz;
 495
 496         if (!p->index_data) {
 497                 struct multi_pack_index *m;
 498                 const char *pack_name = pack_basename(p);
 499
 500                 for (m = the_repository->objects->multi_pack_index;
 501                      m; m = m->next) {
 502                         if (midx_contains_pack(m, pack_name))
 503                                 break;
 504                 }
 505
 506                 if (!m && open_pack_index(p))
 507                         return error("packfile %s index unavailable", p->pack_name);
 508         }
 509
 510         if (!pack_max_fds) {
 511                 unsigned int max_fds = get_max_fd_limit();
 512
 513                 /* Save 3 for stdin/stdout/stderr, 22 for work */
 514                 if (25 < max_fds)
 515                         pack_max_fds = max_fds - 25;
 516                 else
 517                         pack_max_fds = 1;
 518         }
 519
 520         while (pack_max_fds <= pack_open_fds && close_one_pack())
 521                 ; /* nothing */
 522
 523         p->pack_fd = git_open(p->pack_name);
 524         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 525                 return -1;
 526         pack_open_fds++;
 527
 528         /* If we created the struct before we had the pack we lack size. */
 529         if (!p->pack_size) {
 530                 if (!S_ISREG(st.st_mode))
 531                         return error("packfile %s not a regular file", p->pack_name);
 532                 p->pack_size = st.st_size;
 533         } else if (p->pack_size != st.st_size)
 534                 return error("packfile %s size changed", p->pack_name);
 535
 536         /* We leave these file descriptors open with sliding mmap;
 537          * there is no point keeping them open across exec(), though.
 538          */
 539         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 540         if (fd_flag < 0)
 541                 return error("cannot determine file descriptor flags");
 542         fd_flag |= FD_CLOEXEC;
 543         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 544                 return error("cannot set FD_CLOEXEC");
 545
 546         /* Verify we recognize this pack file format. */
 547         read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
 548         if (read_result < 0)
 549                 return error_errno("error reading from %s", p->pack_name);
 550         if (read_result != sizeof(hdr))
 551                 return error("file %s is far too short to be a packfile", p->pack_name);
 552         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 553                 return error("file %s is not a GIT packfile", p->pack_name);
 554         if (!pack_version_ok(hdr.hdr_version))
 555                 return error("packfile %s is version %"PRIu32" and not"
 556                         " supported (try upgrading GIT to a newer version)",
 557                         p->pack_name, ntohl(hdr.hdr_version));
 558
 559         /* Skip index checking if in multi-pack-index */
 560         if (!p->index_data)
 561                 return 0;
 562
 563         /* Verify the pack matches its index. */
 564         if (p->num_objects != ntohl(hdr.hdr_entries))
 565                 return error("packfile %s claims to have %"PRIu32" objects"
 566                              " while index indicates %"PRIu32" objects",
 567                              p->pack_name, ntohl(hdr.hdr_entries),
 568                              p->num_objects);
 569         if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
 570                 return error("end of packfile %s is unavailable", p->pack_name);
 571         read_result = read_in_full(p->pack_fd, hash, hashsz);
 572         if (read_result < 0)
 573                 return error_errno("error reading from %s", p->pack_name);
 574         if (read_result != hashsz)
 575                 return error("packfile %s signature is unavailable", p->pack_name);
 576         idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
 577         if (!hasheq(hash, idx_hash))
 578                 return error("packfile %s does not match index", p->pack_name);
 579         return 0;
 580 }
 581
 582 static int open_packed_git(struct packed_git *p)
 583 {
 584         if (!open_packed_git_1(p))
 585                 return 0;
 586         close_pack_fd(p);
 587         return -1;
 588 }
 589
 590 static int in_window(struct pack_window *win, off_t offset)
 591 {
 592         /* We must promise at least one full hash after the
 593          * offset is available from this window, otherwise the offset
 594          * is not actually in this window and a different window (which
 595          * has that one hash excess) must be used.  This is to support
 596          * the object header and delta base parsing routines below.
 597          */
 598         off_t win_off = win->offset;
 599         return win_off <= offset
 600                 && (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 601 }
 602
 603 unsigned char *use_pack(struct packed_git *p,
 604                 struct pack_window **w_cursor,
 605                 off_t offset,
 606                 unsigned long *left)
 607 {
 608         struct pack_window *win = *w_cursor;
 609
 610         /* Since packfiles end in a hash of their content and it's
 611          * pointless to ask for an offset into the middle of that
 612          * hash, and the in_window function above wouldn't match
 613          * don't allow an offset too close to the end of the file.
 614          */
 615         if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 616                 die("packfile %s cannot be accessed", p->pack_name);
 617         if (offset > (p->pack_size - the_hash_algo->rawsz))
 618                 die("offset beyond end of packfile (truncated pack?)");
 619         if (offset < 0)
 620                 die(_("offset before end of packfile (broken .idx?)"));
 621
 622         if (!win || !in_window(win, offset)) {
 623                 if (win)
 624                         win->inuse_cnt--;
 625                 for (win = p->windows; win; win = win->next) {
 626                         if (in_window(win, offset))
 627                                 break;
 628                 }
 629                 if (!win) {
 630                         size_t window_align = packed_git_window_size / 2;
 631                         off_t len;
 632
 633                         if (p->pack_fd == -1 && open_packed_git(p))
 634                                 die("packfile %s cannot be accessed", p->pack_name);
 635
 636                         win = xcalloc(1, sizeof(*win));
 637                         win->offset = (offset / window_align) * window_align;
 638                         len = p->pack_size - win->offset;
 639                         if (len > packed_git_window_size)
 640                                 len = packed_git_window_size;
 641                         win->len = (size_t)len;
 642                         pack_mapped += win->len;
 643                         while (packed_git_limit < pack_mapped
 644                                 && unuse_one_window(p))
 645                                 ; /* nothing */
 646                         win->base = xmmap_gently(NULL, win->len,
 647                                 PROT_READ, MAP_PRIVATE,
 648                                 p->pack_fd, win->offset);
 649                         if (win->base == MAP_FAILED)
 650                                 die_errno("packfile %s cannot be mapped",
 651                                           p->pack_name);
 652                         if (!win->offset && win->len == p->pack_size
 653                                 && !p->do_not_close)
 654                                 close_pack_fd(p);
 655                         pack_mmap_calls++;
 656                         pack_open_windows++;
 657                         if (pack_mapped > peak_pack_mapped)
 658                                 peak_pack_mapped = pack_mapped;
 659                         if (pack_open_windows > peak_pack_open_windows)
 660                                 peak_pack_open_windows = pack_open_windows;
 661                         win->next = p->windows;
 662                         p->windows = win;
 663                 }
 664         }
 665         if (win != *w_cursor) {
 666                 win->last_used = pack_used_ctr++;
 667                 win->inuse_cnt++;
 668                 *w_cursor = win;
 669         }
 670         offset -= win->offset;
 671         if (left)
 672                 *left = win->len - xsize_t(offset);
 673         return win->base + offset;
 674 }
 675
 676 void unuse_pack(struct pack_window **w_cursor)
 677 {
 678         struct pack_window *w = *w_cursor;
 679         if (w) {
 680                 w->inuse_cnt--;
 681                 *w_cursor = NULL;
 682         }
 683 }
 684
 685 static void try_to_free_pack_memory(size_t size)
 686 {
 687         release_pack_memory(size);
 688 }
 689
 690 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 691 {
 692         static int have_set_try_to_free_routine;
 693         struct stat st;
 694         size_t alloc;
 695         struct packed_git *p;
 696
 697         if (!have_set_try_to_free_routine) {
 698                 have_set_try_to_free_routine = 1;
 699                 set_try_to_free_routine(try_to_free_pack_memory);
 700         }
 701
 702         /*
 703          * Make sure a corresponding .pack file exists and that
 704          * the index looks sane.
 705          */
 706         if (!strip_suffix_mem(path, &path_len, ".idx"))
 707                 return NULL;
 708
 709         /*
 710          * ".promisor" is long enough to hold any suffix we're adding (and
 711          * the use xsnprintf double-checks that)
 712          */
 713         alloc = st_add3(path_len, strlen(".promisor"), 1);
 714         p = alloc_packed_git(alloc);
 715         memcpy(p->pack_name, path, path_len);
 716
 717         xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
 718         if (!access(p->pack_name, F_OK))
 719                 p->pack_keep = 1;
 720
 721         xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
 722         if (!access(p->pack_name, F_OK))
 723                 p->pack_promisor = 1;
 724
 725         xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
 726         if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 727                 free(p);
 728                 return NULL;
 729         }
 730
 731         /* ok, it looks sane as far as we can check without
 732          * actually mapping the pack file.
 733          */
 734         p->pack_size = st.st_size;
 735         p->pack_local = local;
 736         p->mtime = st.st_mtime;
 737         if (path_len < the_hash_algo->hexsz ||
 738             get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->hash))
 739                 hashclr(p->hash);
 740         return p;
 741 }
 742
 743 void install_packed_git(struct repository *r, struct packed_git *pack)
 744 {
 745         if (pack->pack_fd != -1)
 746                 pack_open_fds++;
 747
 748         pack->next = r->objects->packed_git;
 749         r->objects->packed_git = pack;
 750 }
 751
 752 void (*report_garbage)(unsigned seen_bits, const char *path);
 753
 754 static void report_helper(const struct string_list *list,
 755                           int seen_bits, int first, int last)
 756 {
 757         if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
 758                 return;
 759
 760         for (; first < last; first++)
 761                 report_garbage(seen_bits, list->items[first].string);
 762 }
 763
 764 static void report_pack_garbage(struct string_list *list)
 765 {
 766         int i, baselen = -1, first = 0, seen_bits = 0;
 767
 768         if (!report_garbage)
 769                 return;
 770
 771         string_list_sort(list);
 772
 773         for (i = 0; i < list->nr; i++) {
 774                 const char *path = list->items[i].string;
 775                 if (baselen != -1 &&
 776                     strncmp(path, list->items[first].string, baselen)) {
 777                         report_helper(list, seen_bits, first, i);
 778                         baselen = -1;
 779                         seen_bits = 0;
 780                 }
 781                 if (baselen == -1) {
 782                         const char *dot = strrchr(path, '.');
 783                         if (!dot) {
 784                                 report_garbage(PACKDIR_FILE_GARBAGE, path);
 785                                 continue;
 786                         }
 787                         baselen = dot - path + 1;
 788                         first = i;
 789                 }
 790                 if (!strcmp(path + baselen, "pack"))
 791                         seen_bits |= 1;
 792                 else if (!strcmp(path + baselen, "idx"))
 793                         seen_bits |= 2;
 794         }
 795         report_helper(list, seen_bits, first, list->nr);
 796 }
 797
 798 void for_each_file_in_pack_dir(const char *objdir,
 799                                each_file_in_pack_dir_fn fn,
 800                                void *data)
 801 {
 802         struct strbuf path = STRBUF_INIT;
 803         size_t dirnamelen;
 804         DIR *dir;
 805         struct dirent *de;
 806
 807         strbuf_addstr(&path, objdir);
 808         strbuf_addstr(&path, "/pack");
 809         dir = opendir(path.buf);
 810         if (!dir) {
 811                 if (errno != ENOENT)
 812                         error_errno("unable to open object pack directory: %s",
 813                                     path.buf);
 814                 strbuf_release(&path);
 815                 return;
 816         }
 817         strbuf_addch(&path, '/');
 818         dirnamelen = path.len;
 819         while ((de = readdir(dir)) != NULL) {
 820                 if (is_dot_or_dotdot(de->d_name))
 821                         continue;
 822
 823                 strbuf_setlen(&path, dirnamelen);
 824                 strbuf_addstr(&path, de->d_name);
 825
 826                 fn(path.buf, path.len, de->d_name, data);
 827         }
 828
 829         closedir(dir);
 830         strbuf_release(&path);
 831 }
 832
 833 struct prepare_pack_data {
 834         struct repository *r;
 835         struct string_list *garbage;
 836         int local;
 837         struct multi_pack_index *m;
 838 };
 839
 840 static void prepare_pack(const char *full_name, size_t full_name_len,
 841                          const char *file_name, void *_data)
 842 {
 843         struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
 844         struct packed_git *p;
 845         size_t base_len = full_name_len;
 846
 847         if (strip_suffix_mem(full_name, &base_len, ".idx") &&
 848             !(data->m && midx_contains_pack(data->m, file_name))) {
 849                 /* Don't reopen a pack we already have. */
 850                 for (p = data->r->objects->packed_git; p; p = p->next) {
 851                         size_t len;
 852                         if (strip_suffix(p->pack_name, ".pack", &len) &&
 853                             len == base_len &&
 854                             !memcmp(p->pack_name, full_name, len))
 855                                 break;
 856                 }
 857
 858                 if (!p) {
 859                         p = add_packed_git(full_name, full_name_len, data->local);
 860                         if (p)
 861                                 install_packed_git(data->r, p);
 862                 }
 863         }
 864
 865         if (!report_garbage)
 866                 return;
 867
 868         if (!strcmp(file_name, "multi-pack-index"))
 869                 return;
 870         if (ends_with(file_name, ".idx") ||
 871             ends_with(file_name, ".pack") ||
 872             ends_with(file_name, ".bitmap") ||
 873             ends_with(file_name, ".keep") ||
 874             ends_with(file_name, ".promisor"))
 875                 string_list_append(data->garbage, full_name);
 876         else
 877                 report_garbage(PACKDIR_FILE_GARBAGE, full_name);
 878 }
 879
 880 static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
 881 {
 882         struct prepare_pack_data data;
 883         struct string_list garbage = STRING_LIST_INIT_DUP;
 884
 885         data.m = r->objects->multi_pack_index;
 886
 887         /* look for the multi-pack-index for this object directory */
 888         while (data.m && strcmp(data.m->object_dir, objdir))
 889                 data.m = data.m->next;
 890
 891         data.r = r;
 892         data.garbage = &garbage;
 893         data.local = local;
 894
 895         for_each_file_in_pack_dir(objdir, prepare_pack, &data);
 896
 897         report_pack_garbage(data.garbage);
 898         string_list_clear(data.garbage, 0);
 899 }
 900
 901 static void prepare_packed_git(struct repository *r);
 902 /*
 903  * Give a fast, rough count of the number of objects in the repository. This
 904  * ignores loose objects completely. If you have a lot of them, then either
 905  * you should repack because your performance will be awful, or they are
 906  * all unreachable objects about to be pruned, in which case they're not really
 907  * interesting as a measure of repo size in the first place.
 908  */
 909 unsigned long repo_approximate_object_count(struct repository *r)
 910 {
 911         if (!r->objects->approximate_object_count_valid) {
 912                 unsigned long count;
 913                 struct multi_pack_index *m;
 914                 struct packed_git *p;
 915
 916                 prepare_packed_git(r);
 917                 count = 0;
 918                 for (m = get_multi_pack_index(r); m; m = m->next)
 919                         count += m->num_objects;
 920                 for (p = r->objects->packed_git; p; p = p->next) {
 921                         if (open_pack_index(p))
 922                                 continue;
 923                         count += p->num_objects;
 924                 }
 925                 r->objects->approximate_object_count = count;
 926         }
 927         return r->objects->approximate_object_count;
 928 }
 929
 930 static void *get_next_packed_git(const void *p)
 931 {
 932         return ((const struct packed_git *)p)->next;
 933 }
 934
 935 static void set_next_packed_git(void *p, void *next)
 936 {
 937         ((struct packed_git *)p)->next = next;
 938 }
 939
 940 static int sort_pack(const void *a_, const void *b_)
 941 {
 942         const struct packed_git *a = a_;
 943         const struct packed_git *b = b_;
 944         int st;
 945
 946         /*
 947          * Local packs tend to contain objects specific to our
 948          * variant of the project than remote ones.  In addition,
 949          * remote ones could be on a network mounted filesystem.
 950          * Favor local ones for these reasons.
 951          */
 952         st = a->pack_local - b->pack_local;
 953         if (st)
 954                 return -st;
 955
 956         /*
 957          * Younger packs tend to contain more recent objects,
 958          * and more recent objects tend to get accessed more
 959          * often.
 960          */
 961         if (a->mtime < b->mtime)
 962                 return 1;
 963         else if (a->mtime == b->mtime)
 964                 return 0;
 965         return -1;
 966 }
 967
 968 static void rearrange_packed_git(struct repository *r)
 969 {
 970         r->objects->packed_git = llist_mergesort(
 971                 r->objects->packed_git, get_next_packed_git,
 972                 set_next_packed_git, sort_pack);
 973 }
 974
 975 static void prepare_packed_git_mru(struct repository *r)
 976 {
 977         struct packed_git *p;
 978
 979         INIT_LIST_HEAD(&r->objects->packed_git_mru);
 980
 981         for (p = r->objects->packed_git; p; p = p->next)
 982                 list_add_tail(&p->mru, &r->objects->packed_git_mru);
 983 }
 984
 985 static void prepare_packed_git(struct repository *r)
 986 {
 987         struct object_directory *odb;
 988
 989         if (r->objects->packed_git_initialized)
 990                 return;
 991
 992         prepare_alt_odb(r);
 993         for (odb = r->objects->odb; odb; odb = odb->next) {
 994                 int local = (odb == r->objects->odb);
 995                 prepare_multi_pack_index_one(r, odb->path, local);
 996                 prepare_packed_git_one(r, odb->path, local);
 997         }
 998         rearrange_packed_git(r);
 999
1000         prepare_packed_git_mru(r);
1001         r->objects->packed_git_initialized = 1;
1002 }
1003
1004 void reprepare_packed_git(struct repository *r)
1005 {
1006         struct object_directory *odb;
1007
1008         for (odb = r->objects->odb; odb; odb = odb->next)
1009                 odb_clear_loose_cache(odb);
1010
1011         r->objects->approximate_object_count_valid = 0;
1012         r->objects->packed_git_initialized = 0;
1013         prepare_packed_git(r);
1014 }
1015
1016 struct packed_git *get_packed_git(struct repository *r)
1017 {
1018         prepare_packed_git(r);
1019         return r->objects->packed_git;
1020 }
1021
1022 struct multi_pack_index *get_multi_pack_index(struct repository *r)
1023 {
1024         prepare_packed_git(r);
1025         return r->objects->multi_pack_index;
1026 }
1027
1028 struct packed_git *get_all_packs(struct repository *r)
1029 {
1030         struct multi_pack_index *m;
1031
1032         prepare_packed_git(r);
1033         for (m = r->objects->multi_pack_index; m; m = m->next) {
1034                 uint32_t i;
1035                 for (i = 0; i < m->num_packs; i++)
1036                         prepare_midx_pack(r, m, i);
1037         }
1038
1039         return r->objects->packed_git;
1040 }
1041
1042 struct list_head *get_packed_git_mru(struct repository *r)
1043 {
1044         prepare_packed_git(r);
1045         return &r->objects->packed_git_mru;
1046 }
1047
1048 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1049                 unsigned long len, enum object_type *type, unsigned long *sizep)
1050 {
1051         unsigned shift;
1052         unsigned long size, c;
1053         unsigned long used = 0;
1054
1055         c = buf[used++];
1056         *type = (c >> 4) & 7;
1057         size = c & 15;
1058         shift = 4;
1059         while (c & 0x80) {
1060                 if (len <= used || bitsizeof(long) <= shift) {
1061                         error("bad object header");
1062                         size = used = 0;
1063                         break;
1064                 }
1065                 c = buf[used++];
1066                 size += (c & 0x7f) << shift;
1067                 shift += 7;
1068         }
1069         *sizep = size;
1070         return used;
1071 }
1072
1073 unsigned long get_size_from_delta(struct packed_git *p,
1074                                   struct pack_window **w_curs,
1075                                   off_t curpos)
1076 {
1077         const unsigned char *data;
1078         unsigned char delta_head[20], *in;
1079         git_zstream stream;
1080         int st;
1081
1082         memset(&stream, 0, sizeof(stream));
1083         stream.next_out = delta_head;
1084         stream.avail_out = sizeof(delta_head);
1085
1086         git_inflate_init(&stream);
1087         do {
1088                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1089                 stream.next_in = in;
1090                 st = git_inflate(&stream, Z_FINISH);
1091                 curpos += stream.next_in - in;
1092         } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1093                  stream.total_out < sizeof(delta_head));
1094         git_inflate_end(&stream);
1095         if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1096                 error("delta data unpack-initial failed");
1097                 return 0;
1098         }
1099
1100         /* Examine the initial part of the delta to figure out
1101          * the result size.
1102          */
1103         data = delta_head;
1104
1105         /* ignore base size */
1106         get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1107
1108         /* Read the result size */
1109         return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1110 }
1111
1112 int unpack_object_header(struct packed_git *p,
1113                          struct pack_window **w_curs,
1114                          off_t *curpos,
1115                          unsigned long *sizep)
1116 {
1117         unsigned char *base;
1118         unsigned long left;
1119         unsigned long used;
1120         enum object_type type;
1121
1122         /* use_pack() assures us we have [base, base + 20) available
1123          * as a range that we can look at.  (Its actually the hash
1124          * size that is assured.)  With our object header encoding
1125          * the maximum deflated object size is 2^137, which is just
1126          * insane, so we know won't exceed what we have been given.
1127          */
1128         base = use_pack(p, w_curs, *curpos, &left);
1129         used = unpack_object_header_buffer(base, left, &type, sizep);
1130         if (!used) {
1131                 type = OBJ_BAD;
1132         } else
1133                 *curpos += used;
1134
1135         return type;
1136 }
1137
1138 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1139 {
1140         unsigned i;
1141         const unsigned hashsz = the_hash_algo->rawsz;
1142         for (i = 0; i < p->num_bad_objects; i++)
1143                 if (hasheq(sha1, p->bad_object_sha1 + hashsz * i))
1144                         return;
1145         p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1146                                       st_mult(GIT_MAX_RAWSZ,
1147                                               st_add(p->num_bad_objects, 1)));
1148         hashcpy(p->bad_object_sha1 + hashsz * p->num_bad_objects, sha1);
1149         p->num_bad_objects++;
1150 }
1151
1152 const struct packed_git *has_packed_and_bad(struct repository *r,
1153                                             const unsigned char *sha1)
1154 {
1155         struct packed_git *p;
1156         unsigned i;
1157
1158         for (p = r->objects->packed_git; p; p = p->next)
1159                 for (i = 0; i < p->num_bad_objects; i++)
1160                         if (hasheq(sha1,
1161                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1162                                 return p;
1163         return NULL;
1164 }
1165
1166 static off_t get_delta_base(struct packed_git *p,
1167                                     struct pack_window **w_curs,
1168                                     off_t *curpos,
1169                                     enum object_type type,
1170                                     off_t delta_obj_offset)
1171 {
1172         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1173         off_t base_offset;
1174
1175         /* use_pack() assured us we have [base_info, base_info + 20)
1176          * as a range that we can look at without walking off the
1177          * end of the mapped window.  Its actually the hash size
1178          * that is assured.  An OFS_DELTA longer than the hash size
1179          * is stupid, as then a REF_DELTA would be smaller to store.
1180          */
1181         if (type == OBJ_OFS_DELTA) {
1182                 unsigned used = 0;
1183                 unsigned char c = base_info[used++];
1184                 base_offset = c & 127;
1185                 while (c & 128) {
1186                         base_offset += 1;
1187                         if (!base_offset || MSB(base_offset, 7))
1188                                 return 0;  /* overflow */
1189                         c = base_info[used++];
1190                         base_offset = (base_offset << 7) + (c & 127);
1191                 }
1192                 base_offset = delta_obj_offset - base_offset;
1193                 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1194                         return 0;  /* out of bound */
1195                 *curpos += used;
1196         } else if (type == OBJ_REF_DELTA) {
1197                 /* The base entry _must_ be in the same pack */
1198                 base_offset = find_pack_entry_one(base_info, p);
1199                 *curpos += the_hash_algo->rawsz;
1200         } else
1201                 die("I am totally screwed");
1202         return base_offset;
1203 }
1204
1205 /*
1206  * Like get_delta_base above, but we return the sha1 instead of the pack
1207  * offset. This means it is cheaper for REF deltas (we do not have to do
1208  * the final object lookup), but more expensive for OFS deltas (we
1209  * have to load the revidx to convert the offset back into a sha1).
1210  */
1211 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1212                                                 struct pack_window **w_curs,
1213                                                 off_t curpos,
1214                                                 enum object_type type,
1215                                                 off_t delta_obj_offset)
1216 {
1217         if (type == OBJ_REF_DELTA) {
1218                 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1219                 return base;
1220         } else if (type == OBJ_OFS_DELTA) {
1221                 struct revindex_entry *revidx;
1222                 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1223                                                    type, delta_obj_offset);
1224
1225                 if (!base_offset)
1226                         return NULL;
1227
1228                 revidx = find_pack_revindex(p, base_offset);
1229                 if (!revidx)
1230                         return NULL;
1231
1232                 return nth_packed_object_sha1(p, revidx->nr);
1233         } else
1234                 return NULL;
1235 }
1236
1237 static int retry_bad_packed_offset(struct repository *r,
1238                                    struct packed_git *p,
1239                                    off_t obj_offset)
1240 {
1241         int type;
1242         struct revindex_entry *revidx;
1243         struct object_id oid;
1244         revidx = find_pack_revindex(p, obj_offset);
1245         if (!revidx)
1246                 return OBJ_BAD;
1247         nth_packed_object_oid(&oid, p, revidx->nr);
1248         mark_bad_packed_object(p, oid.hash);
1249         type = oid_object_info(r, &oid, NULL);
1250         if (type <= OBJ_NONE)
1251                 return OBJ_BAD;
1252         return type;
1253 }
1254
1255 #define POI_STACK_PREALLOC 64
1256
1257 static enum object_type packed_to_object_type(struct repository *r,
1258                                               struct packed_git *p,
1259                                               off_t obj_offset,
1260                                               enum object_type type,
1261                                               struct pack_window **w_curs,
1262                                               off_t curpos)
1263 {
1264         off_t small_poi_stack[POI_STACK_PREALLOC];
1265         off_t *poi_stack = small_poi_stack;
1266         int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1267
1268         while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1269                 off_t base_offset;
1270                 unsigned long size;
1271                 /* Push the object we're going to leave behind */
1272                 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1273                         poi_stack_alloc = alloc_nr(poi_stack_nr);
1274                         ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1275                         COPY_ARRAY(poi_stack, small_poi_stack, poi_stack_nr);
1276                 } else {
1277                         ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1278                 }
1279                 poi_stack[poi_stack_nr++] = obj_offset;
1280                 /* If parsing the base offset fails, just unwind */
1281                 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1282                 if (!base_offset)
1283                         goto unwind;
1284                 curpos = obj_offset = base_offset;
1285                 type = unpack_object_header(p, w_curs, &curpos, &size);
1286                 if (type <= OBJ_NONE) {
1287                         /* If getting the base itself fails, we first
1288                          * retry the base, otherwise unwind */
1289                         type = retry_bad_packed_offset(r, p, base_offset);
1290                         if (type > OBJ_NONE)
1291                                 goto out;
1292                         goto unwind;
1293                 }
1294         }
1295
1296         switch (type) {
1297         case OBJ_BAD:
1298         case OBJ_COMMIT:
1299         case OBJ_TREE:
1300         case OBJ_BLOB:
1301         case OBJ_TAG:
1302                 break;
1303         default:
1304                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1305                       type, (uintmax_t)obj_offset, p->pack_name);
1306                 type = OBJ_BAD;
1307         }
1308
1309 out:
1310         if (poi_stack != small_poi_stack)
1311                 free(poi_stack);
1312         return type;
1313
1314 unwind:
1315         while (poi_stack_nr) {
1316                 obj_offset = poi_stack[--poi_stack_nr];
1317                 type = retry_bad_packed_offset(r, p, obj_offset);
1318                 if (type > OBJ_NONE)
1319                         goto out;
1320         }
1321         type = OBJ_BAD;
1322         goto out;
1323 }
1324
1325 static struct hashmap delta_base_cache;
1326 static size_t delta_base_cached;
1327
1328 static LIST_HEAD(delta_base_cache_lru);
1329
1330 struct delta_base_cache_key {
1331         struct packed_git *p;
1332         off_t base_offset;
1333 };
1334
1335 struct delta_base_cache_entry {
1336         struct hashmap hash;
1337         struct delta_base_cache_key key;
1338         struct list_head lru;
1339         void *data;
1340         unsigned long size;
1341         enum object_type type;
1342 };
1343
1344 static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1345 {
1346         unsigned int hash;
1347
1348         hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1349         hash += (hash >> 8) + (hash >> 16);
1350         return hash;
1351 }
1352
1353 static struct delta_base_cache_entry *
1354 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1355 {
1356         struct hashmap_entry entry;
1357         struct delta_base_cache_key key;
1358
1359         if (!delta_base_cache.cmpfn)
1360                 return NULL;
1361
1362         hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1363         key.p = p;
1364         key.base_offset = base_offset;
1365         return hashmap_get(&delta_base_cache, &entry, &key);
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 void *va, const void *vb,
1376                                      const void *vkey)
1377 {
1378         const struct delta_base_cache_entry *a = va, *b = vb;
1379         const struct delta_base_cache_key *key = vkey;
1380         if (key)
1381                 return !delta_base_cache_key_eq(&a->key, key);
1382         else
1383                 return !delta_base_cache_key_eq(&a->key, &b->key);
1384 }
1385
1386 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1387 {
1388         return !!get_delta_base_cache_entry(p, base_offset);
1389 }
1390
1391 /*
1392  * Remove the entry from the cache, but do _not_ free the associated
1393  * entry data. The caller takes ownership of the "data" buffer, and
1394  * should copy out any fields it wants before detaching.
1395  */
1396 static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1397 {
1398         hashmap_remove(&delta_base_cache, ent, &ent->key);
1399         list_del(&ent->lru);
1400         delta_base_cached -= ent->size;
1401         free(ent);
1402 }
1403
1404 static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
1405                                    off_t base_offset, unsigned long *base_size,
1406                                    enum object_type *type)
1407 {
1408         struct delta_base_cache_entry *ent;
1409
1410         ent = get_delta_base_cache_entry(p, base_offset);
1411         if (!ent)
1412                 return unpack_entry(r, p, base_offset, type, base_size);
1413
1414         if (type)
1415                 *type = ent->type;
1416         if (base_size)
1417                 *base_size = ent->size;
1418         return xmemdupz(ent->data, ent->size);
1419 }
1420
1421 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1422 {
1423         free(ent->data);
1424         detach_delta_base_cache_entry(ent);
1425 }
1426
1427 void clear_delta_base_cache(void)
1428 {
1429         struct list_head *lru, *tmp;
1430         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1431                 struct delta_base_cache_entry *entry =
1432                         list_entry(lru, struct delta_base_cache_entry, lru);
1433                 release_delta_base_cache(entry);
1434         }
1435 }
1436
1437 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1438         void *base, unsigned long base_size, enum object_type type)
1439 {
1440         struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1441         struct list_head *lru, *tmp;
1442
1443         delta_base_cached += base_size;
1444
1445         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1446                 struct delta_base_cache_entry *f =
1447                         list_entry(lru, struct delta_base_cache_entry, lru);
1448                 if (delta_base_cached <= delta_base_cache_limit)
1449                         break;
1450                 release_delta_base_cache(f);
1451         }
1452
1453         ent->key.p = p;
1454         ent->key.base_offset = base_offset;
1455         ent->type = type;
1456         ent->data = base;
1457         ent->size = base_size;
1458         list_add_tail(&ent->lru, &delta_base_cache_lru);
1459
1460         if (!delta_base_cache.cmpfn)
1461                 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1462         hashmap_entry_init(ent, pack_entry_hash(p, base_offset));
1463         hashmap_add(&delta_base_cache, ent);
1464 }
1465
1466 int packed_object_info(struct repository *r, struct packed_git *p,
1467                        off_t obj_offset, struct object_info *oi)
1468 {
1469         struct pack_window *w_curs = NULL;
1470         unsigned long size;
1471         off_t curpos = obj_offset;
1472         enum object_type type;
1473
1474         /*
1475          * We always get the representation type, but only convert it to
1476          * a "real" type later if the caller is interested.
1477          */
1478         if (oi->contentp) {
1479                 *oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
1480                                                       &type);
1481                 if (!*oi->contentp)
1482                         type = OBJ_BAD;
1483         } else {
1484                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1485         }
1486
1487         if (!oi->contentp && oi->sizep) {
1488                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1489                         off_t tmp_pos = curpos;
1490                         off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1491                                                            type, obj_offset);
1492                         if (!base_offset) {
1493                                 type = OBJ_BAD;
1494                                 goto out;
1495                         }
1496                         *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1497                         if (*oi->sizep == 0) {
1498                                 type = OBJ_BAD;
1499                                 goto out;
1500                         }
1501                 } else {
1502                         *oi->sizep = size;
1503                 }
1504         }
1505
1506         if (oi->disk_sizep) {
1507                 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1508                 *oi->disk_sizep = revidx[1].offset - obj_offset;
1509         }
1510
1511         if (oi->typep || oi->type_name) {
1512                 enum object_type ptot;
1513                 ptot = packed_to_object_type(r, p, obj_offset,
1514                                              type, &w_curs, curpos);
1515                 if (oi->typep)
1516                         *oi->typep = ptot;
1517                 if (oi->type_name) {
1518                         const char *tn = type_name(ptot);
1519                         if (tn)
1520                                 strbuf_addstr(oi->type_name, tn);
1521                 }
1522                 if (ptot < 0) {
1523                         type = OBJ_BAD;
1524                         goto out;
1525                 }
1526         }
1527
1528         if (oi->delta_base_sha1) {
1529                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1530                         const unsigned char *base;
1531
1532                         base = get_delta_base_sha1(p, &w_curs, curpos,
1533                                                    type, obj_offset);
1534                         if (!base) {
1535                                 type = OBJ_BAD;
1536                                 goto out;
1537                         }
1538
1539                         hashcpy(oi->delta_base_sha1, base);
1540                 } else
1541                         hashclr(oi->delta_base_sha1);
1542         }
1543
1544         oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1545                                                           OI_PACKED;
1546
1547 out:
1548         unuse_pack(&w_curs);
1549         return type;
1550 }
1551
1552 static void *unpack_compressed_entry(struct packed_git *p,
1553                                     struct pack_window **w_curs,
1554                                     off_t curpos,
1555                                     unsigned long size)
1556 {
1557         int st;
1558         git_zstream stream;
1559         unsigned char *buffer, *in;
1560
1561         buffer = xmallocz_gently(size);
1562         if (!buffer)
1563                 return NULL;
1564         memset(&stream, 0, sizeof(stream));
1565         stream.next_out = buffer;
1566         stream.avail_out = size + 1;
1567
1568         git_inflate_init(&stream);
1569         do {
1570                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1571                 stream.next_in = in;
1572                 st = git_inflate(&stream, Z_FINISH);
1573                 if (!stream.avail_out)
1574                         break; /* the payload is larger than it should be */
1575                 curpos += stream.next_in - in;
1576         } while (st == Z_OK || st == Z_BUF_ERROR);
1577         git_inflate_end(&stream);
1578         if ((st != Z_STREAM_END) || stream.total_out != size) {
1579                 free(buffer);
1580                 return NULL;
1581         }
1582
1583         /* versions of zlib can clobber unconsumed portion of outbuf */
1584         buffer[size] = '\0';
1585
1586         return buffer;
1587 }
1588
1589 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1590 {
1591         static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1592         trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1593                          p->pack_name, (uintmax_t)obj_offset);
1594 }
1595
1596 int do_check_packed_object_crc;
1597
1598 #define UNPACK_ENTRY_STACK_PREALLOC 64
1599 struct unpack_entry_stack_ent {
1600         off_t obj_offset;
1601         off_t curpos;
1602         unsigned long size;
1603 };
1604
1605 static void *read_object(struct repository *r,
1606                          const struct object_id *oid,
1607                          enum object_type *type,
1608                          unsigned long *size)
1609 {
1610         struct object_info oi = OBJECT_INFO_INIT;
1611         void *content;
1612         oi.typep = type;
1613         oi.sizep = size;
1614         oi.contentp = &content;
1615
1616         if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1617                 return NULL;
1618         return content;
1619 }
1620
1621 void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
1622                    enum object_type *final_type, unsigned long *final_size)
1623 {
1624         struct pack_window *w_curs = NULL;
1625         off_t curpos = obj_offset;
1626         void *data = NULL;
1627         unsigned long size;
1628         enum object_type type;
1629         struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1630         struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1631         int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1632         int base_from_cache = 0;
1633
1634         write_pack_access_log(p, obj_offset);
1635
1636         /* PHASE 1: drill down to the innermost base object */
1637         for (;;) {
1638                 off_t base_offset;
1639                 int i;
1640                 struct delta_base_cache_entry *ent;
1641
1642                 ent = get_delta_base_cache_entry(p, curpos);
1643                 if (ent) {
1644                         type = ent->type;
1645                         data = ent->data;
1646                         size = ent->size;
1647                         detach_delta_base_cache_entry(ent);
1648                         base_from_cache = 1;
1649                         break;
1650                 }
1651
1652                 if (do_check_packed_object_crc && p->index_version > 1) {
1653                         struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1654                         off_t len = revidx[1].offset - obj_offset;
1655                         if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1656                                 struct object_id oid;
1657                                 nth_packed_object_oid(&oid, p, revidx->nr);
1658                                 error("bad packed object CRC for %s",
1659                                       oid_to_hex(&oid));
1660                                 mark_bad_packed_object(p, oid.hash);
1661                                 data = NULL;
1662                                 goto out;
1663                         }
1664                 }
1665
1666                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1667                 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1668                         break;
1669
1670                 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1671                 if (!base_offset) {
1672                         error("failed to validate delta base reference "
1673                               "at offset %"PRIuMAX" from %s",
1674                               (uintmax_t)curpos, p->pack_name);
1675                         /* bail to phase 2, in hopes of recovery */
1676                         data = NULL;
1677                         break;
1678                 }
1679
1680                 /* push object, proceed to base */
1681                 if (delta_stack_nr >= delta_stack_alloc
1682                     && delta_stack == small_delta_stack) {
1683                         delta_stack_alloc = alloc_nr(delta_stack_nr);
1684                         ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1685                         COPY_ARRAY(delta_stack, small_delta_stack,
1686                                    delta_stack_nr);
1687                 } else {
1688                         ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1689                 }
1690                 i = delta_stack_nr++;
1691                 delta_stack[i].obj_offset = obj_offset;
1692                 delta_stack[i].curpos = curpos;
1693                 delta_stack[i].size = size;
1694
1695                 curpos = obj_offset = base_offset;
1696         }
1697
1698         /* PHASE 2: handle the base */
1699         switch (type) {
1700         case OBJ_OFS_DELTA:
1701         case OBJ_REF_DELTA:
1702                 if (data)
1703                         BUG("unpack_entry: left loop at a valid delta");
1704                 break;
1705         case OBJ_COMMIT:
1706         case OBJ_TREE:
1707         case OBJ_BLOB:
1708         case OBJ_TAG:
1709                 if (!base_from_cache)
1710                         data = unpack_compressed_entry(p, &w_curs, curpos, size);
1711                 break;
1712         default:
1713                 data = NULL;
1714                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1715                       type, (uintmax_t)obj_offset, p->pack_name);
1716         }
1717
1718         /* PHASE 3: apply deltas in order */
1719
1720         /* invariants:
1721          *   'data' holds the base data, or NULL if there was corruption
1722          */
1723         while (delta_stack_nr) {
1724                 void *delta_data;
1725                 void *base = data;
1726                 void *external_base = NULL;
1727                 unsigned long delta_size, base_size = size;
1728                 int i;
1729
1730                 data = NULL;
1731
1732                 if (base)
1733                         add_delta_base_cache(p, obj_offset, base, base_size, type);
1734
1735                 if (!base) {
1736                         /*
1737                          * We're probably in deep shit, but let's try to fetch
1738                          * the required base anyway from another pack or loose.
1739                          * This is costly but should happen only in the presence
1740                          * of a corrupted pack, and is better than failing outright.
1741                          */
1742                         struct revindex_entry *revidx;
1743                         struct object_id base_oid;
1744                         revidx = find_pack_revindex(p, obj_offset);
1745                         if (revidx) {
1746                                 nth_packed_object_oid(&base_oid, p, revidx->nr);
1747                                 error("failed to read delta base object %s"
1748                                       " at offset %"PRIuMAX" from %s",
1749                                       oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1750                                       p->pack_name);
1751                                 mark_bad_packed_object(p, base_oid.hash);
1752                                 base = read_object(r, &base_oid, &type, &base_size);
1753                                 external_base = base;
1754                         }
1755                 }
1756
1757                 i = --delta_stack_nr;
1758                 obj_offset = delta_stack[i].obj_offset;
1759                 curpos = delta_stack[i].curpos;
1760                 delta_size = delta_stack[i].size;
1761
1762                 if (!base)
1763                         continue;
1764
1765                 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1766
1767                 if (!delta_data) {
1768                         error("failed to unpack compressed delta "
1769                               "at offset %"PRIuMAX" from %s",
1770                               (uintmax_t)curpos, p->pack_name);
1771                         data = NULL;
1772                         free(external_base);
1773                         continue;
1774                 }
1775
1776                 data = patch_delta(base, base_size,
1777                                    delta_data, delta_size,
1778                                    &size);
1779
1780                 /*
1781                  * We could not apply the delta; warn the user, but keep going.
1782                  * Our failure will be noticed either in the next iteration of
1783                  * the loop, or if this is the final delta, in the caller when
1784                  * we return NULL. Those code paths will take care of making
1785                  * a more explicit warning and retrying with another copy of
1786                  * the object.
1787                  */
1788                 if (!data)
1789                         error("failed to apply delta");
1790
1791                 free(delta_data);
1792                 free(external_base);
1793         }
1794
1795         if (final_type)
1796                 *final_type = type;
1797         if (final_size)
1798                 *final_size = size;
1799
1800 out:
1801         unuse_pack(&w_curs);
1802
1803         if (delta_stack != small_delta_stack)
1804                 free(delta_stack);
1805
1806         return data;
1807 }
1808
1809 int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1810 {
1811         const unsigned char *index_fanout = p->index_data;
1812         const unsigned char *index_lookup;
1813         const unsigned int hashsz = the_hash_algo->rawsz;
1814         int index_lookup_width;
1815
1816         if (!index_fanout)
1817                 BUG("bsearch_pack called without a valid pack-index");
1818
1819         index_lookup = index_fanout + 4 * 256;
1820         if (p->index_version == 1) {
1821                 index_lookup_width = hashsz + 4;
1822                 index_lookup += 4;
1823         } else {
1824                 index_lookup_width = hashsz;
1825                 index_fanout += 8;
1826                 index_lookup += 8;
1827         }
1828
1829         return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1830                             index_lookup, index_lookup_width, result);
1831 }
1832
1833 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1834                                             uint32_t n)
1835 {
1836         const unsigned char *index = p->index_data;
1837         const unsigned int hashsz = the_hash_algo->rawsz;
1838         if (!index) {
1839                 if (open_pack_index(p))
1840                         return NULL;
1841                 index = p->index_data;
1842         }
1843         if (n >= p->num_objects)
1844                 return NULL;
1845         index += 4 * 256;
1846         if (p->index_version == 1) {
1847                 return index + (hashsz + 4) * n + 4;
1848         } else {
1849                 index += 8;
1850                 return index + hashsz * n;
1851         }
1852 }
1853
1854 const struct object_id *nth_packed_object_oid(struct object_id *oid,
1855                                               struct packed_git *p,
1856                                               uint32_t n)
1857 {
1858         const unsigned char *hash = nth_packed_object_sha1(p, n);
1859         if (!hash)
1860                 return NULL;
1861         hashcpy(oid->hash, hash);
1862         return oid;
1863 }
1864
1865 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1866 {
1867         const unsigned char *ptr = vptr;
1868         const unsigned char *start = p->index_data;
1869         const unsigned char *end = start + p->index_size;
1870         if (ptr < start)
1871                 die(_("offset before start of pack index for %s (corrupt index?)"),
1872                     p->pack_name);
1873         /* No need to check for underflow; .idx files must be at least 8 bytes */
1874         if (ptr >= end - 8)
1875                 die(_("offset beyond end of pack index for %s (truncated index?)"),
1876                     p->pack_name);
1877 }
1878
1879 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1880 {
1881         const unsigned char *index = p->index_data;
1882         const unsigned int hashsz = the_hash_algo->rawsz;
1883         index += 4 * 256;
1884         if (p->index_version == 1) {
1885                 return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
1886         } else {
1887                 uint32_t off;
1888                 index += 8 + p->num_objects * (hashsz + 4);
1889                 off = ntohl(*((uint32_t *)(index + 4 * n)));
1890                 if (!(off & 0x80000000))
1891                         return off;
1892                 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1893                 check_pack_index_ptr(p, index);
1894                 return get_be64(index);
1895         }
1896 }
1897
1898 off_t find_pack_entry_one(const unsigned char *sha1,
1899                                   struct packed_git *p)
1900 {
1901         const unsigned char *index = p->index_data;
1902         struct object_id oid;
1903         uint32_t result;
1904
1905         if (!index) {
1906                 if (open_pack_index(p))
1907                         return 0;
1908         }
1909
1910         hashcpy(oid.hash, sha1);
1911         if (bsearch_pack(&oid, p, &result))
1912                 return nth_packed_object_offset(p, result);
1913         return 0;
1914 }
1915
1916 int is_pack_valid(struct packed_git *p)
1917 {
1918         /* An already open pack is known to be valid. */
1919         if (p->pack_fd != -1)
1920                 return 1;
1921
1922         /* If the pack has one window completely covering the
1923          * file size, the pack is known to be valid even if
1924          * the descriptor is not currently open.
1925          */
1926         if (p->windows) {
1927                 struct pack_window *w = p->windows;
1928
1929                 if (!w->offset && w->len == p->pack_size)
1930                         return 1;
1931         }
1932
1933         /* Force the pack to open to prove its valid. */
1934         return !open_packed_git(p);
1935 }
1936
1937 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1938                                   struct packed_git *packs)
1939 {
1940         struct packed_git *p;
1941
1942         for (p = packs; p; p = p->next) {
1943                 if (find_pack_entry_one(sha1, p))
1944                         return p;
1945         }
1946         return NULL;
1947
1948 }
1949
1950 static int fill_pack_entry(const struct object_id *oid,
1951                            struct pack_entry *e,
1952                            struct packed_git *p)
1953 {
1954         off_t offset;
1955
1956         if (p->num_bad_objects) {
1957                 unsigned i;
1958                 for (i = 0; i < p->num_bad_objects; i++)
1959                         if (hasheq(oid->hash,
1960                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1961                                 return 0;
1962         }
1963
1964         offset = find_pack_entry_one(oid->hash, p);
1965         if (!offset)
1966                 return 0;
1967
1968         /*
1969          * We are about to tell the caller where they can locate the
1970          * requested object.  We better make sure the packfile is
1971          * still here and can be accessed before supplying that
1972          * answer, as it may have been deleted since the index was
1973          * loaded!
1974          */
1975         if (!is_pack_valid(p))
1976                 return 0;
1977         e->offset = offset;
1978         e->p = p;
1979         return 1;
1980 }
1981
1982 int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
1983 {
1984         struct list_head *pos;
1985         struct multi_pack_index *m;
1986
1987         prepare_packed_git(r);
1988         if (!r->objects->packed_git && !r->objects->multi_pack_index)
1989                 return 0;
1990
1991         for (m = r->objects->multi_pack_index; m; m = m->next) {
1992                 if (fill_midx_entry(r, oid, e, m))
1993                         return 1;
1994         }
1995
1996         list_for_each(pos, &r->objects->packed_git_mru) {
1997                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
1998                 if (!p->multi_pack_index && fill_pack_entry(oid, e, p)) {
1999                         list_move(&p->mru, &r->objects->packed_git_mru);
2000                         return 1;
2001                 }
2002         }
2003         return 0;
2004 }
2005
2006 int has_object_pack(const struct object_id *oid)
2007 {
2008         struct pack_entry e;
2009         return find_pack_entry(the_repository, oid, &e);
2010 }
2011
2012 int has_pack_index(const unsigned char *sha1)
2013 {
2014         struct stat st;
2015         if (stat(sha1_pack_index_name(sha1), &st))
2016                 return 0;
2017         return 1;
2018 }
2019
2020 int for_each_object_in_pack(struct packed_git *p,
2021                             each_packed_object_fn cb, void *data,
2022                             enum for_each_object_flags flags)
2023 {
2024         uint32_t i;
2025         int r = 0;
2026
2027         if (flags & FOR_EACH_OBJECT_PACK_ORDER) {
2028                 if (load_pack_revindex(p))
2029                         return -1;
2030         }
2031
2032         for (i = 0; i < p->num_objects; i++) {
2033                 uint32_t pos;
2034                 struct object_id oid;
2035
2036                 if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2037                         pos = p->revindex[i].nr;
2038                 else
2039                         pos = i;
2040
2041                 if (!nth_packed_object_oid(&oid, p, pos))
2042                         return error("unable to get sha1 of object %u in %s",
2043                                      pos, p->pack_name);
2044
2045                 r = cb(&oid, p, pos, data);
2046                 if (r)
2047                         break;
2048         }
2049         return r;
2050 }
2051
2052 int for_each_packed_object(each_packed_object_fn cb, void *data,
2053                            enum for_each_object_flags flags)
2054 {
2055         struct packed_git *p;
2056         int r = 0;
2057         int pack_errors = 0;
2058
2059         prepare_packed_git(the_repository);
2060         for (p = get_all_packs(the_repository); p; p = p->next) {
2061                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2062                         continue;
2063                 if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
2064                     !p->pack_promisor)
2065                         continue;
2066                 if (open_pack_index(p)) {
2067                         pack_errors = 1;
2068                         continue;
2069                 }
2070                 r = for_each_object_in_pack(p, cb, data, flags);
2071                 if (r)
2072                         break;
2073         }
2074         return r ? r : pack_errors;
2075 }
2076
2077 static int add_promisor_object(const struct object_id *oid,
2078                                struct packed_git *pack,
2079                                uint32_t pos,
2080                                void *set_)
2081 {
2082         struct oidset *set = set_;
2083         struct object *obj = parse_object(the_repository, oid);
2084         if (!obj)
2085                 return 1;
2086
2087         oidset_insert(set, oid);
2088
2089         /*
2090          * If this is a tree, commit, or tag, the objects it refers
2091          * to are also promisor objects. (Blobs refer to no objects->)
2092          */
2093         if (obj->type == OBJ_TREE) {
2094                 struct tree *tree = (struct tree *)obj;
2095                 struct tree_desc desc;
2096                 struct name_entry entry;
2097                 if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
2098                         /*
2099                          * Error messages are given when packs are
2100                          * verified, so do not print any here.
2101                          */
2102                         return 0;
2103                 while (tree_entry_gently(&desc, &entry))
2104                         oidset_insert(set, &entry.oid);
2105         } else if (obj->type == OBJ_COMMIT) {
2106                 struct commit *commit = (struct commit *) obj;
2107                 struct commit_list *parents = commit->parents;
2108
2109                 oidset_insert(set, get_commit_tree_oid(commit));
2110                 for (; parents; parents = parents->next)
2111                         oidset_insert(set, &parents->item->object.oid);
2112         } else if (obj->type == OBJ_TAG) {
2113                 struct tag *tag = (struct tag *) obj;
2114                 oidset_insert(set, &tag->tagged->oid);
2115         }
2116         return 0;
2117 }
2118
2119 int is_promisor_object(const struct object_id *oid)
2120 {
2121         static struct oidset promisor_objects;
2122         static int promisor_objects_prepared;
2123
2124         if (!promisor_objects_prepared) {
2125                 if (repository_format_partial_clone) {
2126                         for_each_packed_object(add_promisor_object,
2127                                                &promisor_objects,
2128                                                FOR_EACH_OBJECT_PROMISOR_ONLY);
2129                 }
2130                 promisor_objects_prepared = 1;
2131         }
2132         return oidset_contains(&promisor_objects, oid);
2133 }