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