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
  20 char *odb_pack_name(struct strbuf *buf,
  21                     const unsigned char *sha1,
  22                     const char *ext)
  23 {
  24         strbuf_reset(buf);
  25         strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
  26                     sha1_to_hex(sha1), ext);
  27         return buf->buf;
  28 }
  29
  30 char *sha1_pack_name(const unsigned char *sha1)
  31 {
  32         static struct strbuf buf = STRBUF_INIT;
  33         return odb_pack_name(&buf, sha1, "pack");
  34 }
  35
  36 char *sha1_pack_index_name(const unsigned char *sha1)
  37 {
  38         static struct strbuf buf = STRBUF_INIT;
  39         return odb_pack_name(&buf, sha1, "idx");
  40 }
  41
  42 static unsigned int pack_used_ctr;
  43 static unsigned int pack_mmap_calls;
  44 static unsigned int peak_pack_open_windows;
  45 static unsigned int pack_open_windows;
  46 static unsigned int pack_open_fds;
  47 static unsigned int pack_max_fds;
  48 static size_t peak_pack_mapped;
  49 static size_t pack_mapped;
  50
  51 #define SZ_FMT PRIuMAX
  52 static inline uintmax_t sz_fmt(size_t s) { return s; }
  53
  54 void pack_report(void)
  55 {
  56         fprintf(stderr,
  57                 "pack_report: getpagesize()            = %10" SZ_FMT "\n"
  58                 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
  59                 "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
  60                 sz_fmt(getpagesize()),
  61                 sz_fmt(packed_git_window_size),
  62                 sz_fmt(packed_git_limit));
  63         fprintf(stderr,
  64                 "pack_report: pack_used_ctr            = %10u\n"
  65                 "pack_report: pack_mmap_calls          = %10u\n"
  66                 "pack_report: pack_open_windows        = %10u / %10u\n"
  67                 "pack_report: pack_mapped              = "
  68                         "%10" SZ_FMT " / %10" SZ_FMT "\n",
  69                 pack_used_ctr,
  70                 pack_mmap_calls,
  71                 pack_open_windows, peak_pack_open_windows,
  72                 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
  73 }
  74
  75 /*
  76  * Open and mmap the index file at path, perform a couple of
  77  * consistency checks, then record its information to p.  Return 0 on
  78  * success.
  79  */
  80 static int check_packed_git_idx(const char *path, struct packed_git *p)
  81 {
  82         void *idx_map;
  83         size_t idx_size;
  84         int fd = git_open(path), ret;
  85         struct stat st;
  86         const unsigned int hashsz = the_hash_algo->rawsz;
  87
  88         if (fd < 0)
  89                 return -1;
  90         if (fstat(fd, &st)) {
  91                 close(fd);
  92                 return -1;
  93         }
  94         idx_size = xsize_t(st.st_size);
  95         if (idx_size < 4 * 256 + hashsz + hashsz) {
  96                 close(fd);
  97                 return error("index file %s is too small", path);
  98         }
  99         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 100         close(fd);
 101
 102         ret = load_idx(path, hashsz, idx_map, idx_size, p);
 103
 104         if (ret)
 105                 munmap(idx_map, idx_size);
 106
 107         return ret;
 108 }
 109
 110 int load_idx(const char *path, const unsigned int hashsz, void *idx_map,
 111              size_t idx_size, struct packed_git *p)
 112 {
 113         struct pack_idx_header *hdr = idx_map;
 114         uint32_t version, nr, i, *index;
 115
 116         if (idx_size < 4 * 256 + hashsz + hashsz)
 117                 return error("index file %s is too small", path);
 118         if (idx_map == NULL)
 119                 return error("empty data");
 120
 121         if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 122                 version = ntohl(hdr->idx_version);
 123                 if (version < 2 || version > 2)
 124                         return error("index file %s is version %"PRIu32
 125                                      " and is not supported by this binary"
 126                                      " (try upgrading GIT to a newer version)",
 127                                      path, version);
 128         } else
 129                 version = 1;
 130
 131         nr = 0;
 132         index = idx_map;
 133         if (version > 1)
 134                 index += 2;  /* skip index header */
 135         for (i = 0; i < 256; i++) {
 136                 uint32_t n = ntohl(index[i]);
 137                 if (n < nr)
 138                         return error("non-monotonic index %s", path);
 139                 nr = n;
 140         }
 141
 142         if (version == 1) {
 143                 /*
 144                  * Total size:
 145                  *  - 256 index entries 4 bytes each
 146                  *  - 24-byte entries * nr (object ID + 4-byte offset)
 147                  *  - hash of the packfile
 148                  *  - file checksum
 149                  */
 150                 if (idx_size != 4 * 256 + nr * (hashsz + 4) + hashsz + hashsz)
 151                         return error("wrong index v1 file size in %s", path);
 152         } else if (version == 2) {
 153                 /*
 154                  * Minimum size:
 155                  *  - 8 bytes of header
 156                  *  - 256 index entries 4 bytes each
 157                  *  - object ID entry * nr
 158                  *  - 4-byte crc entry * nr
 159                  *  - 4-byte offset entry * nr
 160                  *  - hash of the packfile
 161                  *  - file checksum
 162                  * And after the 4-byte offset table might be a
 163                  * variable sized table containing 8-byte entries
 164                  * for offsets larger than 2^31.
 165                  */
 166                 unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
 167                 unsigned long max_size = min_size;
 168                 if (nr)
 169                         max_size += (nr - 1)*8;
 170                 if (idx_size < min_size || idx_size > max_size)
 171                         return error("wrong index v2 file size in %s", path);
 172                 if (idx_size != min_size &&
 173                     /*
 174                      * make sure we can deal with large pack offsets.
 175                      * 31-bit signed offset won't be enough, neither
 176                      * 32-bit unsigned one will be.
 177                      */
 178                     (sizeof(off_t) <= 4))
 179                         return error("pack too large for current definition of off_t in %s", path);
 180         }
 181
 182         p->index_version = version;
 183         p->index_data = idx_map;
 184         p->index_size = idx_size;
 185         p->num_objects = nr;
 186         return 0;
 187 }
 188
 189 int open_pack_index(struct packed_git *p)
 190 {
 191         char *idx_name;
 192         size_t len;
 193         int ret;
 194
 195         if (p->index_data)
 196                 return 0;
 197
 198         if (!strip_suffix(p->pack_name, ".pack", &len))
 199                 BUG("pack_name does not end in .pack");
 200         idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 201         ret = check_packed_git_idx(idx_name, p);
 202         free(idx_name);
 203         return ret;
 204 }
 205
 206 uint32_t get_pack_fanout(struct packed_git *p, uint32_t value)
 207 {
 208         const uint32_t *level1_ofs = p->index_data;
 209
 210         if (!level1_ofs) {
 211                 if (open_pack_index(p))
 212                         return 0;
 213                 level1_ofs = p->index_data;
 214         }
 215
 216         if (p->index_version > 1) {
 217                 level1_ofs += 2;
 218         }
 219
 220         return ntohl(level1_ofs[value]);
 221 }
 222
 223 static struct packed_git *alloc_packed_git(int extra)
 224 {
 225         struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
 226         memset(p, 0, sizeof(*p));
 227         p->pack_fd = -1;
 228         return p;
 229 }
 230
 231 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 232 {
 233         const char *path = sha1_pack_name(sha1);
 234         size_t alloc = st_add(strlen(path), 1);
 235         struct packed_git *p = alloc_packed_git(alloc);
 236
 237         memcpy(p->pack_name, path, alloc); /* includes NUL */
 238         hashcpy(p->sha1, sha1);
 239         if (check_packed_git_idx(idx_path, p)) {
 240                 free(p);
 241                 return NULL;
 242         }
 243
 244         return p;
 245 }
 246
 247 static void scan_windows(struct packed_git *p,
 248         struct packed_git **lru_p,
 249         struct pack_window **lru_w,
 250         struct pack_window **lru_l)
 251 {
 252         struct pack_window *w, *w_l;
 253
 254         for (w_l = NULL, w = p->windows; w; w = w->next) {
 255                 if (!w->inuse_cnt) {
 256                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 257                                 *lru_p = p;
 258                                 *lru_w = w;
 259                                 *lru_l = w_l;
 260                         }
 261                 }
 262                 w_l = w;
 263         }
 264 }
 265
 266 static int unuse_one_window(struct packed_git *current)
 267 {
 268         struct packed_git *p, *lru_p = NULL;
 269         struct pack_window *lru_w = NULL, *lru_l = NULL;
 270
 271         if (current)
 272                 scan_windows(current, &lru_p, &lru_w, &lru_l);
 273         for (p = the_repository->objects->packed_git; p; p = p->next)
 274                 scan_windows(p, &lru_p, &lru_w, &lru_l);
 275         if (lru_p) {
 276                 munmap(lru_w->base, lru_w->len);
 277                 pack_mapped -= lru_w->len;
 278                 if (lru_l)
 279                         lru_l->next = lru_w->next;
 280                 else
 281                         lru_p->windows = lru_w->next;
 282                 free(lru_w);
 283                 pack_open_windows--;
 284                 return 1;
 285         }
 286         return 0;
 287 }
 288
 289 void release_pack_memory(size_t need)
 290 {
 291         size_t cur = pack_mapped;
 292         while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
 293                 ; /* nothing */
 294 }
 295
 296 void close_pack_windows(struct packed_git *p)
 297 {
 298         while (p->windows) {
 299                 struct pack_window *w = p->windows;
 300
 301                 if (w->inuse_cnt)
 302                         die("pack '%s' still has open windows to it",
 303                             p->pack_name);
 304                 munmap(w->base, w->len);
 305                 pack_mapped -= w->len;
 306                 pack_open_windows--;
 307                 p->windows = w->next;
 308                 free(w);
 309         }
 310 }
 311
 312 static int close_pack_fd(struct packed_git *p)
 313 {
 314         if (p->pack_fd < 0)
 315                 return 0;
 316
 317         close(p->pack_fd);
 318         pack_open_fds--;
 319         p->pack_fd = -1;
 320
 321         return 1;
 322 }
 323
 324 void close_pack_index(struct packed_git *p)
 325 {
 326         if (p->index_data) {
 327                 munmap((void *)p->index_data, p->index_size);
 328                 p->index_data = NULL;
 329         }
 330 }
 331
 332 void close_pack(struct packed_git *p)
 333 {
 334         close_pack_windows(p);
 335         close_pack_fd(p);
 336         close_pack_index(p);
 337 }
 338
 339 void close_all_packs(struct raw_object_store *o)
 340 {
 341         struct packed_git *p;
 342
 343         for (p = o->packed_git; p; p = p->next)
 344                 if (p->do_not_close)
 345                         BUG("want to close pack marked 'do-not-close'");
 346                 else
 347                         close_pack(p);
 348 }
 349
 350 /*
 351  * The LRU pack is the one with the oldest MRU window, preferring packs
 352  * with no used windows, or the oldest mtime if it has no windows allocated.
 353  */
 354 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 355 {
 356         struct pack_window *w, *this_mru_w;
 357         int has_windows_inuse = 0;
 358
 359         /*
 360          * Reject this pack if it has windows and the previously selected
 361          * one does not.  If this pack does not have windows, reject
 362          * it if the pack file is newer than the previously selected one.
 363          */
 364         if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 365                 return;
 366
 367         for (w = this_mru_w = p->windows; w; w = w->next) {
 368                 /*
 369                  * Reject this pack if any of its windows are in use,
 370                  * but the previously selected pack did not have any
 371                  * inuse windows.  Otherwise, record that this pack
 372                  * has windows in use.
 373                  */
 374                 if (w->inuse_cnt) {
 375                         if (*accept_windows_inuse)
 376                                 has_windows_inuse = 1;
 377                         else
 378                                 return;
 379                 }
 380
 381                 if (w->last_used > this_mru_w->last_used)
 382                         this_mru_w = w;
 383
 384                 /*
 385                  * Reject this pack if it has windows that have been
 386                  * used more recently than the previously selected pack.
 387                  * If the previously selected pack had windows inuse and
 388                  * we have not encountered a window in this pack that is
 389                  * inuse, skip this check since we prefer a pack with no
 390                  * inuse windows to one that has inuse windows.
 391                  */
 392                 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 393                     this_mru_w->last_used > (*mru_w)->last_used)
 394                         return;
 395         }
 396
 397         /*
 398          * Select this pack.
 399          */
 400         *mru_w = this_mru_w;
 401         *lru_p = p;
 402         *accept_windows_inuse = has_windows_inuse;
 403 }
 404
 405 static int close_one_pack(void)
 406 {
 407         struct packed_git *p, *lru_p = NULL;
 408         struct pack_window *mru_w = NULL;
 409         int accept_windows_inuse = 1;
 410
 411         for (p = the_repository->objects->packed_git; p; p = p->next) {
 412                 if (p->pack_fd == -1)
 413                         continue;
 414                 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 415         }
 416
 417         if (lru_p)
 418                 return close_pack_fd(lru_p);
 419
 420         return 0;
 421 }
 422
 423 static unsigned int get_max_fd_limit(void)
 424 {
 425 #ifdef RLIMIT_NOFILE
 426         {
 427                 struct rlimit lim;
 428
 429                 if (!getrlimit(RLIMIT_NOFILE, &lim))
 430                         return lim.rlim_cur;
 431         }
 432 #endif
 433
 434 #ifdef _SC_OPEN_MAX
 435         {
 436                 long open_max = sysconf(_SC_OPEN_MAX);
 437                 if (0 < open_max)
 438                         return open_max;
 439                 /*
 440                  * Otherwise, we got -1 for one of the two
 441                  * reasons:
 442                  *
 443                  * (1) sysconf() did not understand _SC_OPEN_MAX
 444                  *     and signaled an error with -1; or
 445                  * (2) sysconf() said there is no limit.
 446                  *
 447                  * We _could_ clear errno before calling sysconf() to
 448                  * tell these two cases apart and return a huge number
 449                  * in the latter case to let the caller cap it to a
 450                  * value that is not so selfish, but letting the
 451                  * fallback OPEN_MAX codepath take care of these cases
 452                  * is a lot simpler.
 453                  */
 454         }
 455 #endif
 456
 457 #ifdef OPEN_MAX
 458         return OPEN_MAX;
 459 #else
 460         return 1; /* see the caller ;-) */
 461 #endif
 462 }
 463
 464 /*
 465  * Do not call this directly as this leaks p->pack_fd on error return;
 466  * call open_packed_git() instead.
 467  */
 468 static int open_packed_git_1(struct packed_git *p)
 469 {
 470         struct stat st;
 471         struct pack_header hdr;
 472         unsigned char hash[GIT_MAX_RAWSZ];
 473         unsigned char *idx_hash;
 474         long fd_flag;
 475         ssize_t read_result;
 476         const unsigned hashsz = the_hash_algo->rawsz;
 477
 478         if (!p->index_data) {
 479                 struct multi_pack_index *m;
 480                 const char *pack_name = strrchr(p->pack_name, '/');
 481
 482                 for (m = the_repository->objects->multi_pack_index;
 483                      m; m = m->next) {
 484                         if (midx_contains_pack(m, pack_name))
 485                                 break;
 486                 }
 487
 488                 if (!m && open_pack_index(p))
 489                         return error("packfile %s index unavailable", p->pack_name);
 490         }
 491
 492         if (!pack_max_fds) {
 493                 unsigned int max_fds = get_max_fd_limit();
 494
 495                 /* Save 3 for stdin/stdout/stderr, 22 for work */
 496                 if (25 < max_fds)
 497                         pack_max_fds = max_fds - 25;
 498                 else
 499                         pack_max_fds = 1;
 500         }
 501
 502         while (pack_max_fds <= pack_open_fds && close_one_pack())
 503                 ; /* nothing */
 504
 505         p->pack_fd = git_open(p->pack_name);
 506         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 507                 return -1;
 508         pack_open_fds++;
 509
 510         /* If we created the struct before we had the pack we lack size. */
 511         if (!p->pack_size) {
 512                 if (!S_ISREG(st.st_mode))
 513                         return error("packfile %s not a regular file", p->pack_name);
 514                 p->pack_size = st.st_size;
 515         } else if (p->pack_size != st.st_size)
 516                 return error("packfile %s size changed", p->pack_name);
 517
 518         /* We leave these file descriptors open with sliding mmap;
 519          * there is no point keeping them open across exec(), though.
 520          */
 521         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 522         if (fd_flag < 0)
 523                 return error("cannot determine file descriptor flags");
 524         fd_flag |= FD_CLOEXEC;
 525         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 526                 return error("cannot set FD_CLOEXEC");
 527
 528         /* Verify we recognize this pack file format. */
 529         read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
 530         if (read_result < 0)
 531                 return error_errno("error reading from %s", p->pack_name);
 532         if (read_result != sizeof(hdr))
 533                 return error("file %s is far too short to be a packfile", p->pack_name);
 534         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 535                 return error("file %s is not a GIT packfile", p->pack_name);
 536         if (!pack_version_ok(hdr.hdr_version))
 537                 return error("packfile %s is version %"PRIu32" and not"
 538                         " supported (try upgrading GIT to a newer version)",
 539                         p->pack_name, ntohl(hdr.hdr_version));
 540
 541         /* Skip index checking if in multi-pack-index */
 542         if (!p->index_data)
 543                 return 0;
 544
 545         /* Verify the pack matches its index. */
 546         if (p->num_objects != ntohl(hdr.hdr_entries))
 547                 return error("packfile %s claims to have %"PRIu32" objects"
 548                              " while index indicates %"PRIu32" objects",
 549                              p->pack_name, ntohl(hdr.hdr_entries),
 550                              p->num_objects);
 551         if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
 552                 return error("end of packfile %s is unavailable", p->pack_name);
 553         read_result = read_in_full(p->pack_fd, hash, hashsz);
 554         if (read_result < 0)
 555                 return error_errno("error reading from %s", p->pack_name);
 556         if (read_result != hashsz)
 557                 return error("packfile %s signature is unavailable", p->pack_name);
 558         idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
 559         if (!hasheq(hash, idx_hash))
 560                 return error("packfile %s does not match index", p->pack_name);
 561         return 0;
 562 }
 563
 564 static int open_packed_git(struct packed_git *p)
 565 {
 566         if (!open_packed_git_1(p))
 567                 return 0;
 568         close_pack_fd(p);
 569         return -1;
 570 }
 571
 572 static int in_window(struct pack_window *win, off_t offset)
 573 {
 574         /* We must promise at least one full hash after the
 575          * offset is available from this window, otherwise the offset
 576          * is not actually in this window and a different window (which
 577          * has that one hash excess) must be used.  This is to support
 578          * the object header and delta base parsing routines below.
 579          */
 580         off_t win_off = win->offset;
 581         return win_off <= offset
 582                 && (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 583 }
 584
 585 unsigned char *use_pack(struct packed_git *p,
 586                 struct pack_window **w_cursor,
 587                 off_t offset,
 588                 unsigned long *left)
 589 {
 590         struct pack_window *win = *w_cursor;
 591
 592         /* Since packfiles end in a hash of their content and it's
 593          * pointless to ask for an offset into the middle of that
 594          * hash, and the in_window function above wouldn't match
 595          * don't allow an offset too close to the end of the file.
 596          */
 597         if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 598                 die("packfile %s cannot be accessed", p->pack_name);
 599         if (offset > (p->pack_size - the_hash_algo->rawsz))
 600                 die("offset beyond end of packfile (truncated pack?)");
 601         if (offset < 0)
 602                 die(_("offset before end of packfile (broken .idx?)"));
 603
 604         if (!win || !in_window(win, offset)) {
 605                 if (win)
 606                         win->inuse_cnt--;
 607                 for (win = p->windows; win; win = win->next) {
 608                         if (in_window(win, offset))
 609                                 break;
 610                 }
 611                 if (!win) {
 612                         size_t window_align = packed_git_window_size / 2;
 613                         off_t len;
 614
 615                         if (p->pack_fd == -1 && open_packed_git(p))
 616                                 die("packfile %s cannot be accessed", p->pack_name);
 617
 618                         win = xcalloc(1, sizeof(*win));
 619                         win->offset = (offset / window_align) * window_align;
 620                         len = p->pack_size - win->offset;
 621                         if (len > packed_git_window_size)
 622                                 len = packed_git_window_size;
 623                         win->len = (size_t)len;
 624                         pack_mapped += win->len;
 625                         while (packed_git_limit < pack_mapped
 626                                 && unuse_one_window(p))
 627                                 ; /* nothing */
 628                         win->base = xmmap(NULL, win->len,
 629                                 PROT_READ, MAP_PRIVATE,
 630                                 p->pack_fd, win->offset);
 631                         if (win->base == MAP_FAILED)
 632                                 die_errno("packfile %s cannot be mapped",
 633                                           p->pack_name);
 634                         if (!win->offset && win->len == p->pack_size
 635                                 && !p->do_not_close)
 636                                 close_pack_fd(p);
 637                         pack_mmap_calls++;
 638                         pack_open_windows++;
 639                         if (pack_mapped > peak_pack_mapped)
 640                                 peak_pack_mapped = pack_mapped;
 641                         if (pack_open_windows > peak_pack_open_windows)
 642                                 peak_pack_open_windows = pack_open_windows;
 643                         win->next = p->windows;
 644                         p->windows = win;
 645                 }
 646         }
 647         if (win != *w_cursor) {
 648                 win->last_used = pack_used_ctr++;
 649                 win->inuse_cnt++;
 650                 *w_cursor = win;
 651         }
 652         offset -= win->offset;
 653         if (left)
 654                 *left = win->len - xsize_t(offset);
 655         return win->base + offset;
 656 }
 657
 658 void unuse_pack(struct pack_window **w_cursor)
 659 {
 660         struct pack_window *w = *w_cursor;
 661         if (w) {
 662                 w->inuse_cnt--;
 663                 *w_cursor = NULL;
 664         }
 665 }
 666
 667 static void try_to_free_pack_memory(size_t size)
 668 {
 669         release_pack_memory(size);
 670 }
 671
 672 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 673 {
 674         static int have_set_try_to_free_routine;
 675         struct stat st;
 676         size_t alloc;
 677         struct packed_git *p;
 678
 679         if (!have_set_try_to_free_routine) {
 680                 have_set_try_to_free_routine = 1;
 681                 set_try_to_free_routine(try_to_free_pack_memory);
 682         }
 683
 684         /*
 685          * Make sure a corresponding .pack file exists and that
 686          * the index looks sane.
 687          */
 688         if (!strip_suffix_mem(path, &path_len, ".idx"))
 689                 return NULL;
 690
 691         /*
 692          * ".promisor" is long enough to hold any suffix we're adding (and
 693          * the use xsnprintf double-checks that)
 694          */
 695         alloc = st_add3(path_len, strlen(".promisor"), 1);
 696         p = alloc_packed_git(alloc);
 697         memcpy(p->pack_name, path, path_len);
 698
 699         xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
 700         if (!access(p->pack_name, F_OK))
 701                 p->pack_keep = 1;
 702
 703         xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
 704         if (!access(p->pack_name, F_OK))
 705                 p->pack_promisor = 1;
 706
 707         xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
 708         if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 709                 free(p);
 710                 return NULL;
 711         }
 712
 713         /* ok, it looks sane as far as we can check without
 714          * actually mapping the pack file.
 715          */
 716         p->pack_size = st.st_size;
 717         p->pack_local = local;
 718         p->mtime = st.st_mtime;
 719         if (path_len < the_hash_algo->hexsz ||
 720             get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->sha1))
 721                 hashclr(p->sha1);
 722         return p;
 723 }
 724
 725 void install_packed_git(struct repository *r, struct packed_git *pack)
 726 {
 727         if (pack->pack_fd != -1)
 728                 pack_open_fds++;
 729
 730         pack->next = r->objects->packed_git;
 731         r->objects->packed_git = pack;
 732 }
 733
 734 void (*report_garbage)(unsigned seen_bits, const char *path);
 735
 736 static void report_helper(const struct string_list *list,
 737                           int seen_bits, int first, int last)
 738 {
 739         if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
 740                 return;
 741
 742         for (; first < last; first++)
 743                 report_garbage(seen_bits, list->items[first].string);
 744 }
 745
 746 static void report_pack_garbage(struct string_list *list)
 747 {
 748         int i, baselen = -1, first = 0, seen_bits = 0;
 749
 750         if (!report_garbage)
 751                 return;
 752
 753         string_list_sort(list);
 754
 755         for (i = 0; i < list->nr; i++) {
 756                 const char *path = list->items[i].string;
 757                 if (baselen != -1 &&
 758                     strncmp(path, list->items[first].string, baselen)) {
 759                         report_helper(list, seen_bits, first, i);
 760                         baselen = -1;
 761                         seen_bits = 0;
 762                 }
 763                 if (baselen == -1) {
 764                         const char *dot = strrchr(path, '.');
 765                         if (!dot) {
 766                                 report_garbage(PACKDIR_FILE_GARBAGE, path);
 767                                 continue;
 768                         }
 769                         baselen = dot - path + 1;
 770                         first = i;
 771                 }
 772                 if (!strcmp(path + baselen, "pack"))
 773                         seen_bits |= 1;
 774                 else if (!strcmp(path + baselen, "idx"))
 775                         seen_bits |= 2;
 776         }
 777         report_helper(list, seen_bits, first, list->nr);
 778 }
 779
 780 void for_each_file_in_pack_dir(const char *objdir,
 781                                each_file_in_pack_dir_fn fn,
 782                                void *data)
 783 {
 784         struct strbuf path = STRBUF_INIT;
 785         size_t dirnamelen;
 786         DIR *dir;
 787         struct dirent *de;
 788
 789         strbuf_addstr(&path, objdir);
 790         strbuf_addstr(&path, "/pack");
 791         dir = opendir(path.buf);
 792         if (!dir) {
 793                 if (errno != ENOENT)
 794                         error_errno("unable to open object pack directory: %s",
 795                                     path.buf);
 796                 strbuf_release(&path);
 797                 return;
 798         }
 799         strbuf_addch(&path, '/');
 800         dirnamelen = path.len;
 801         while ((de = readdir(dir)) != NULL) {
 802                 if (is_dot_or_dotdot(de->d_name))
 803                         continue;
 804
 805                 strbuf_setlen(&path, dirnamelen);
 806                 strbuf_addstr(&path, de->d_name);
 807
 808                 fn(path.buf, path.len, de->d_name, data);
 809         }
 810
 811         closedir(dir);
 812         strbuf_release(&path);
 813 }
 814
 815 struct prepare_pack_data {
 816         struct repository *r;
 817         struct string_list *garbage;
 818         int local;
 819         struct multi_pack_index *m;
 820 };
 821
 822 static void prepare_pack(const char *full_name, size_t full_name_len,
 823                          const char *file_name, void *_data)
 824 {
 825         struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
 826         struct packed_git *p;
 827         size_t base_len = full_name_len;
 828
 829         if (strip_suffix_mem(full_name, &base_len, ".idx") &&
 830             !(data->m && midx_contains_pack(data->m, file_name))) {
 831                 /* Don't reopen a pack we already have. */
 832                 for (p = data->r->objects->packed_git; p; p = p->next) {
 833                         size_t len;
 834                         if (strip_suffix(p->pack_name, ".pack", &len) &&
 835                             len == base_len &&
 836                             !memcmp(p->pack_name, full_name, len))
 837                                 break;
 838                 }
 839
 840                 if (!p) {
 841                         p = add_packed_git(full_name, full_name_len, data->local);
 842                         if (p)
 843                                 install_packed_git(data->r, p);
 844                 }
 845         }
 846
 847         if (!report_garbage)
 848                 return;
 849
 850         if (!strcmp(file_name, "multi-pack-index"))
 851                 return;
 852         if (ends_with(file_name, ".idx") ||
 853             ends_with(file_name, ".pack") ||
 854             ends_with(file_name, ".bitmap") ||
 855             ends_with(file_name, ".keep") ||
 856             ends_with(file_name, ".promisor"))
 857                 string_list_append(data->garbage, full_name);
 858         else
 859                 report_garbage(PACKDIR_FILE_GARBAGE, full_name);
 860 }
 861
 862 static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
 863 {
 864         struct prepare_pack_data data;
 865         struct string_list garbage = STRING_LIST_INIT_DUP;
 866
 867         data.m = r->objects->multi_pack_index;
 868
 869         /* look for the multi-pack-index for this object directory */
 870         while (data.m && strcmp(data.m->object_dir, objdir))
 871                 data.m = data.m->next;
 872
 873         data.r = r;
 874         data.garbage = &garbage;
 875         data.local = local;
 876
 877         for_each_file_in_pack_dir(objdir, prepare_pack, &data);
 878
 879         report_pack_garbage(data.garbage);
 880         string_list_clear(data.garbage, 0);
 881 }
 882
 883 static void prepare_packed_git(struct repository *r);
 884 /*
 885  * Give a fast, rough count of the number of objects in the repository. This
 886  * ignores loose objects completely. If you have a lot of them, then either
 887  * you should repack because your performance will be awful, or they are
 888  * all unreachable objects about to be pruned, in which case they're not really
 889  * interesting as a measure of repo size in the first place.
 890  */
 891 unsigned long approximate_object_count(void)
 892 {
 893         if (!the_repository->objects->approximate_object_count_valid) {
 894                 unsigned long count;
 895                 struct multi_pack_index *m;
 896                 struct packed_git *p;
 897
 898                 prepare_packed_git(the_repository);
 899                 count = 0;
 900                 for (m = get_multi_pack_index(the_repository); m; m = m->next)
 901                         count += m->num_objects;
 902                 for (p = the_repository->objects->packed_git; p; p = p->next) {
 903                         if (open_pack_index(p))
 904                                 continue;
 905                         count += p->num_objects;
 906                 }
 907                 the_repository->objects->approximate_object_count = count;
 908         }
 909         return the_repository->objects->approximate_object_count;
 910 }
 911
 912 static void *get_next_packed_git(const void *p)
 913 {
 914         return ((const struct packed_git *)p)->next;
 915 }
 916
 917 static void set_next_packed_git(void *p, void *next)
 918 {
 919         ((struct packed_git *)p)->next = next;
 920 }
 921
 922 static int sort_pack(const void *a_, const void *b_)
 923 {
 924         const struct packed_git *a = a_;
 925         const struct packed_git *b = b_;
 926         int st;
 927
 928         /*
 929          * Local packs tend to contain objects specific to our
 930          * variant of the project than remote ones.  In addition,
 931          * remote ones could be on a network mounted filesystem.
 932          * Favor local ones for these reasons.
 933          */
 934         st = a->pack_local - b->pack_local;
 935         if (st)
 936                 return -st;
 937
 938         /*
 939          * Younger packs tend to contain more recent objects,
 940          * and more recent objects tend to get accessed more
 941          * often.
 942          */
 943         if (a->mtime < b->mtime)
 944                 return 1;
 945         else if (a->mtime == b->mtime)
 946                 return 0;
 947         return -1;
 948 }
 949
 950 static void rearrange_packed_git(struct repository *r)
 951 {
 952         r->objects->packed_git = llist_mergesort(
 953                 r->objects->packed_git, get_next_packed_git,
 954                 set_next_packed_git, sort_pack);
 955 }
 956
 957 static void prepare_packed_git_mru(struct repository *r)
 958 {
 959         struct packed_git *p;
 960
 961         INIT_LIST_HEAD(&r->objects->packed_git_mru);
 962
 963         for (p = r->objects->packed_git; p; p = p->next)
 964                 list_add_tail(&p->mru, &r->objects->packed_git_mru);
 965 }
 966
 967 static void prepare_packed_git(struct repository *r)
 968 {
 969         struct alternate_object_database *alt;
 970
 971         if (r->objects->packed_git_initialized)
 972                 return;
 973         prepare_multi_pack_index_one(r, r->objects->objectdir, 1);
 974         prepare_packed_git_one(r, r->objects->objectdir, 1);
 975         prepare_alt_odb(r);
 976         for (alt = r->objects->alt_odb_list; alt; alt = alt->next) {
 977                 prepare_multi_pack_index_one(r, alt->path, 0);
 978                 prepare_packed_git_one(r, alt->path, 0);
 979         }
 980         rearrange_packed_git(r);
 981
 982         r->objects->all_packs = NULL;
 983
 984         prepare_packed_git_mru(r);
 985         r->objects->packed_git_initialized = 1;
 986 }
 987
 988 void reprepare_packed_git(struct repository *r)
 989 {
 990         r->objects->approximate_object_count_valid = 0;
 991         r->objects->packed_git_initialized = 0;
 992         prepare_packed_git(r);
 993 }
 994
 995 struct packed_git *get_packed_git(struct repository *r)
 996 {
 997         prepare_packed_git(r);
 998         return r->objects->packed_git;
 999 }
1000
1001 struct multi_pack_index *get_multi_pack_index(struct repository *r)
1002 {
1003         prepare_packed_git(r);
1004         return r->objects->multi_pack_index;
1005 }
1006
1007 struct packed_git *get_all_packs(struct repository *r)
1008 {
1009         prepare_packed_git(r);
1010
1011         if (!r->objects->all_packs) {
1012                 struct packed_git *p = r->objects->packed_git;
1013                 struct multi_pack_index *m;
1014
1015                 for (m = r->objects->multi_pack_index; m; m = m->next) {
1016                         uint32_t i;
1017                         for (i = 0; i < m->num_packs; i++) {
1018                                 if (!prepare_midx_pack(m, i)) {
1019                                         m->packs[i]->next = p;
1020                                         p = m->packs[i];
1021                                 }
1022                         }
1023                 }
1024
1025                 r->objects->all_packs = p;
1026         }
1027
1028         return r->objects->all_packs;
1029 }
1030
1031 struct list_head *get_packed_git_mru(struct repository *r)
1032 {
1033         prepare_packed_git(r);
1034         return &r->objects->packed_git_mru;
1035 }
1036
1037 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1038                 unsigned long len, enum object_type *type, unsigned long *sizep)
1039 {
1040         unsigned shift;
1041         unsigned long size, c;
1042         unsigned long used = 0;
1043
1044         c = buf[used++];
1045         *type = (c >> 4) & 7;
1046         size = c & 15;
1047         shift = 4;
1048         while (c & 0x80) {
1049                 if (len <= used || bitsizeof(long) <= shift) {
1050                         error("bad object header");
1051                         size = used = 0;
1052                         break;
1053                 }
1054                 c = buf[used++];
1055                 size += (c & 0x7f) << shift;
1056                 shift += 7;
1057         }
1058         *sizep = size;
1059         return used;
1060 }
1061
1062 unsigned long get_size_from_delta(struct packed_git *p,
1063                                   struct pack_window **w_curs,
1064                                   off_t curpos)
1065 {
1066         const unsigned char *data;
1067         unsigned char delta_head[20], *in;
1068         git_zstream stream;
1069         int st;
1070
1071         memset(&stream, 0, sizeof(stream));
1072         stream.next_out = delta_head;
1073         stream.avail_out = sizeof(delta_head);
1074
1075         git_inflate_init(&stream);
1076         do {
1077                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1078                 stream.next_in = in;
1079                 st = git_inflate(&stream, Z_FINISH);
1080                 curpos += stream.next_in - in;
1081         } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1082                  stream.total_out < sizeof(delta_head));
1083         git_inflate_end(&stream);
1084         if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1085                 error("delta data unpack-initial failed");
1086                 return 0;
1087         }
1088
1089         /* Examine the initial part of the delta to figure out
1090          * the result size.
1091          */
1092         data = delta_head;
1093
1094         /* ignore base size */
1095         get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1096
1097         /* Read the result size */
1098         return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1099 }
1100
1101 int unpack_object_header(struct packed_git *p,
1102                          struct pack_window **w_curs,
1103                          off_t *curpos,
1104                          unsigned long *sizep)
1105 {
1106         unsigned char *base;
1107         unsigned long left;
1108         unsigned long used;
1109         enum object_type type;
1110
1111         /* use_pack() assures us we have [base, base + 20) available
1112          * as a range that we can look at.  (Its actually the hash
1113          * size that is assured.)  With our object header encoding
1114          * the maximum deflated object size is 2^137, which is just
1115          * insane, so we know won't exceed what we have been given.
1116          */
1117         base = use_pack(p, w_curs, *curpos, &left);
1118         used = unpack_object_header_buffer(base, left, &type, sizep);
1119         if (!used) {
1120                 type = OBJ_BAD;
1121         } else
1122                 *curpos += used;
1123
1124         return type;
1125 }
1126
1127 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1128 {
1129         unsigned i;
1130         for (i = 0; i < p->num_bad_objects; i++)
1131                 if (hasheq(sha1, p->bad_object_sha1 + GIT_SHA1_RAWSZ * i))
1132                         return;
1133         p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1134                                       st_mult(GIT_MAX_RAWSZ,
1135                                               st_add(p->num_bad_objects, 1)));
1136         hashcpy(p->bad_object_sha1 + GIT_SHA1_RAWSZ * p->num_bad_objects, sha1);
1137         p->num_bad_objects++;
1138 }
1139
1140 const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
1141 {
1142         struct packed_git *p;
1143         unsigned i;
1144
1145         for (p = the_repository->objects->packed_git; p; p = p->next)
1146                 for (i = 0; i < p->num_bad_objects; i++)
1147                         if (hasheq(sha1,
1148                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1149                                 return p;
1150         return NULL;
1151 }
1152
1153 static off_t get_delta_base(struct packed_git *p,
1154                                     struct pack_window **w_curs,
1155                                     off_t *curpos,
1156                                     enum object_type type,
1157                                     off_t delta_obj_offset)
1158 {
1159         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1160         off_t base_offset;
1161
1162         /* use_pack() assured us we have [base_info, base_info + 20)
1163          * as a range that we can look at without walking off the
1164          * end of the mapped window.  Its actually the hash size
1165          * that is assured.  An OFS_DELTA longer than the hash size
1166          * is stupid, as then a REF_DELTA would be smaller to store.
1167          */
1168         if (type == OBJ_OFS_DELTA) {
1169                 unsigned used = 0;
1170                 unsigned char c = base_info[used++];
1171                 base_offset = c & 127;
1172                 while (c & 128) {
1173                         base_offset += 1;
1174                         if (!base_offset || MSB(base_offset, 7))
1175                                 return 0;  /* overflow */
1176                         c = base_info[used++];
1177                         base_offset = (base_offset << 7) + (c & 127);
1178                 }
1179                 base_offset = delta_obj_offset - base_offset;
1180                 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1181                         return 0;  /* out of bound */
1182                 *curpos += used;
1183         } else if (type == OBJ_REF_DELTA) {
1184                 /* The base entry _must_ be in the same pack */
1185                 base_offset = find_pack_entry_one(base_info, p);
1186                 *curpos += the_hash_algo->rawsz;
1187         } else
1188                 die("I am totally screwed");
1189         return base_offset;
1190 }
1191
1192 /*
1193  * Like get_delta_base above, but we return the sha1 instead of the pack
1194  * offset. This means it is cheaper for REF deltas (we do not have to do
1195  * the final object lookup), but more expensive for OFS deltas (we
1196  * have to load the revidx to convert the offset back into a sha1).
1197  */
1198 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1199                                                 struct pack_window **w_curs,
1200                                                 off_t curpos,
1201                                                 enum object_type type,
1202                                                 off_t delta_obj_offset)
1203 {
1204         if (type == OBJ_REF_DELTA) {
1205                 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1206                 return base;
1207         } else if (type == OBJ_OFS_DELTA) {
1208                 struct revindex_entry *revidx;
1209                 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1210                                                    type, delta_obj_offset);
1211
1212                 if (!base_offset)
1213                         return NULL;
1214
1215                 revidx = find_pack_revindex(p, base_offset);
1216                 if (!revidx)
1217                         return NULL;
1218
1219                 return nth_packed_object_sha1(p, revidx->nr);
1220         } else
1221                 return NULL;
1222 }
1223
1224 static int retry_bad_packed_offset(struct repository *r,
1225                                    struct packed_git *p,
1226                                    off_t obj_offset)
1227 {
1228         int type;
1229         struct revindex_entry *revidx;
1230         struct object_id oid;
1231         revidx = find_pack_revindex(p, obj_offset);
1232         if (!revidx)
1233                 return OBJ_BAD;
1234         nth_packed_object_oid(&oid, p, revidx->nr);
1235         mark_bad_packed_object(p, oid.hash);
1236         type = oid_object_info(r, &oid, NULL);
1237         if (type <= OBJ_NONE)
1238                 return OBJ_BAD;
1239         return type;
1240 }
1241
1242 #define POI_STACK_PREALLOC 64
1243
1244 static enum object_type packed_to_object_type(struct repository *r,
1245                                               struct packed_git *p,
1246                                               off_t obj_offset,
1247                                               enum object_type type,
1248                                               struct pack_window **w_curs,
1249                                               off_t curpos)
1250 {
1251         off_t small_poi_stack[POI_STACK_PREALLOC];
1252         off_t *poi_stack = small_poi_stack;
1253         int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1254
1255         while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1256                 off_t base_offset;
1257                 unsigned long size;
1258                 /* Push the object we're going to leave behind */
1259                 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1260                         poi_stack_alloc = alloc_nr(poi_stack_nr);
1261                         ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1262                         memcpy(poi_stack, small_poi_stack, sizeof(off_t)*poi_stack_nr);
1263                 } else {
1264                         ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1265                 }
1266                 poi_stack[poi_stack_nr++] = obj_offset;
1267                 /* If parsing the base offset fails, just unwind */
1268                 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1269                 if (!base_offset)
1270                         goto unwind;
1271                 curpos = obj_offset = base_offset;
1272                 type = unpack_object_header(p, w_curs, &curpos, &size);
1273                 if (type <= OBJ_NONE) {
1274                         /* If getting the base itself fails, we first
1275                          * retry the base, otherwise unwind */
1276                         type = retry_bad_packed_offset(r, p, base_offset);
1277                         if (type > OBJ_NONE)
1278                                 goto out;
1279                         goto unwind;
1280                 }
1281         }
1282
1283         switch (type) {
1284         case OBJ_BAD:
1285         case OBJ_COMMIT:
1286         case OBJ_TREE:
1287         case OBJ_BLOB:
1288         case OBJ_TAG:
1289                 break;
1290         default:
1291                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1292                       type, (uintmax_t)obj_offset, p->pack_name);
1293                 type = OBJ_BAD;
1294         }
1295
1296 out:
1297         if (poi_stack != small_poi_stack)
1298                 free(poi_stack);
1299         return type;
1300
1301 unwind:
1302         while (poi_stack_nr) {
1303                 obj_offset = poi_stack[--poi_stack_nr];
1304                 type = retry_bad_packed_offset(r, p, obj_offset);
1305                 if (type > OBJ_NONE)
1306                         goto out;
1307         }
1308         type = OBJ_BAD;
1309         goto out;
1310 }
1311
1312 static struct hashmap delta_base_cache;
1313 static size_t delta_base_cached;
1314
1315 static LIST_HEAD(delta_base_cache_lru);
1316
1317 struct delta_base_cache_key {
1318         struct packed_git *p;
1319         off_t base_offset;
1320 };
1321
1322 struct delta_base_cache_entry {
1323         struct hashmap hash;
1324         struct delta_base_cache_key key;
1325         struct list_head lru;
1326         void *data;
1327         unsigned long size;
1328         enum object_type type;
1329 };
1330
1331 static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1332 {
1333         unsigned int hash;
1334
1335         hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1336         hash += (hash >> 8) + (hash >> 16);
1337         return hash;
1338 }
1339
1340 static struct delta_base_cache_entry *
1341 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1342 {
1343         struct hashmap_entry entry;
1344         struct delta_base_cache_key key;
1345
1346         if (!delta_base_cache.cmpfn)
1347                 return NULL;
1348
1349         hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1350         key.p = p;
1351         key.base_offset = base_offset;
1352         return hashmap_get(&delta_base_cache, &entry, &key);
1353 }
1354
1355 static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
1356                                    const struct delta_base_cache_key *b)
1357 {
1358         return a->p == b->p && a->base_offset == b->base_offset;
1359 }
1360
1361 static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
1362                                      const void *va, const void *vb,
1363                                      const void *vkey)
1364 {
1365         const struct delta_base_cache_entry *a = va, *b = vb;
1366         const struct delta_base_cache_key *key = vkey;
1367         if (key)
1368                 return !delta_base_cache_key_eq(&a->key, key);
1369         else
1370                 return !delta_base_cache_key_eq(&a->key, &b->key);
1371 }
1372
1373 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1374 {
1375         return !!get_delta_base_cache_entry(p, base_offset);
1376 }
1377
1378 /*
1379  * Remove the entry from the cache, but do _not_ free the associated
1380  * entry data. The caller takes ownership of the "data" buffer, and
1381  * should copy out any fields it wants before detaching.
1382  */
1383 static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1384 {
1385         hashmap_remove(&delta_base_cache, ent, &ent->key);
1386         list_del(&ent->lru);
1387         delta_base_cached -= ent->size;
1388         free(ent);
1389 }
1390
1391 static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
1392                                    off_t base_offset, unsigned long *base_size,
1393                                    enum object_type *type)
1394 {
1395         struct delta_base_cache_entry *ent;
1396
1397         ent = get_delta_base_cache_entry(p, base_offset);
1398         if (!ent)
1399                 return unpack_entry(r, p, base_offset, type, base_size);
1400
1401         if (type)
1402                 *type = ent->type;
1403         if (base_size)
1404                 *base_size = ent->size;
1405         return xmemdupz(ent->data, ent->size);
1406 }
1407
1408 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1409 {
1410         free(ent->data);
1411         detach_delta_base_cache_entry(ent);
1412 }
1413
1414 void clear_delta_base_cache(void)
1415 {
1416         struct list_head *lru, *tmp;
1417         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1418                 struct delta_base_cache_entry *entry =
1419                         list_entry(lru, struct delta_base_cache_entry, lru);
1420                 release_delta_base_cache(entry);
1421         }
1422 }
1423
1424 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1425         void *base, unsigned long base_size, enum object_type type)
1426 {
1427         struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1428         struct list_head *lru, *tmp;
1429
1430         delta_base_cached += base_size;
1431
1432         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1433                 struct delta_base_cache_entry *f =
1434                         list_entry(lru, struct delta_base_cache_entry, lru);
1435                 if (delta_base_cached <= delta_base_cache_limit)
1436                         break;
1437                 release_delta_base_cache(f);
1438         }
1439
1440         ent->key.p = p;
1441         ent->key.base_offset = base_offset;
1442         ent->type = type;
1443         ent->data = base;
1444         ent->size = base_size;
1445         list_add_tail(&ent->lru, &delta_base_cache_lru);
1446
1447         if (!delta_base_cache.cmpfn)
1448                 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1449         hashmap_entry_init(ent, pack_entry_hash(p, base_offset));
1450         hashmap_add(&delta_base_cache, ent);
1451 }
1452
1453 int packed_object_info(struct repository *r, struct packed_git *p,
1454                        off_t obj_offset, struct object_info *oi)
1455 {
1456         struct pack_window *w_curs = NULL;
1457         unsigned long size;
1458         off_t curpos = obj_offset;
1459         enum object_type type;
1460
1461         /*
1462          * We always get the representation type, but only convert it to
1463          * a "real" type later if the caller is interested.
1464          */
1465         if (oi->contentp) {
1466                 *oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
1467                                                       &type);
1468                 if (!*oi->contentp)
1469                         type = OBJ_BAD;
1470         } else {
1471                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1472         }
1473
1474         if (!oi->contentp && oi->sizep) {
1475                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1476                         off_t tmp_pos = curpos;
1477                         off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1478                                                            type, obj_offset);
1479                         if (!base_offset) {
1480                                 type = OBJ_BAD;
1481                                 goto out;
1482                         }
1483                         *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1484                         if (*oi->sizep == 0) {
1485                                 type = OBJ_BAD;
1486                                 goto out;
1487                         }
1488                 } else {
1489                         *oi->sizep = size;
1490                 }
1491         }
1492
1493         if (oi->disk_sizep) {
1494                 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1495                 *oi->disk_sizep = revidx[1].offset - obj_offset;
1496         }
1497
1498         if (oi->typep || oi->type_name) {
1499                 enum object_type ptot;
1500                 ptot = packed_to_object_type(r, p, obj_offset,
1501                                              type, &w_curs, curpos);
1502                 if (oi->typep)
1503                         *oi->typep = ptot;
1504                 if (oi->type_name) {
1505                         const char *tn = type_name(ptot);
1506                         if (tn)
1507                                 strbuf_addstr(oi->type_name, tn);
1508                 }
1509                 if (ptot < 0) {
1510                         type = OBJ_BAD;
1511                         goto out;
1512                 }
1513         }
1514
1515         if (oi->delta_base_sha1) {
1516                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1517                         const unsigned char *base;
1518
1519                         base = get_delta_base_sha1(p, &w_curs, curpos,
1520                                                    type, obj_offset);
1521                         if (!base) {
1522                                 type = OBJ_BAD;
1523                                 goto out;
1524                         }
1525
1526                         hashcpy(oi->delta_base_sha1, base);
1527                 } else
1528                         hashclr(oi->delta_base_sha1);
1529         }
1530
1531         oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1532                                                           OI_PACKED;
1533
1534 out:
1535         unuse_pack(&w_curs);
1536         return type;
1537 }
1538
1539 static void *unpack_compressed_entry(struct packed_git *p,
1540                                     struct pack_window **w_curs,
1541                                     off_t curpos,
1542                                     unsigned long size)
1543 {
1544         int st;
1545         git_zstream stream;
1546         unsigned char *buffer, *in;
1547
1548         buffer = xmallocz_gently(size);
1549         if (!buffer)
1550                 return NULL;
1551         memset(&stream, 0, sizeof(stream));
1552         stream.next_out = buffer;
1553         stream.avail_out = size + 1;
1554
1555         git_inflate_init(&stream);
1556         do {
1557                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1558                 stream.next_in = in;
1559                 st = git_inflate(&stream, Z_FINISH);
1560                 if (!stream.avail_out)
1561                         break; /* the payload is larger than it should be */
1562                 curpos += stream.next_in - in;
1563         } while (st == Z_OK || st == Z_BUF_ERROR);
1564         git_inflate_end(&stream);
1565         if ((st != Z_STREAM_END) || stream.total_out != size) {
1566                 free(buffer);
1567                 return NULL;
1568         }
1569
1570         /* versions of zlib can clobber unconsumed portion of outbuf */
1571         buffer[size] = '\0';
1572
1573         return buffer;
1574 }
1575
1576 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1577 {
1578         static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1579         trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1580                          p->pack_name, (uintmax_t)obj_offset);
1581 }
1582
1583 int do_check_packed_object_crc;
1584
1585 #define UNPACK_ENTRY_STACK_PREALLOC 64
1586 struct unpack_entry_stack_ent {
1587         off_t obj_offset;
1588         off_t curpos;
1589         unsigned long size;
1590 };
1591
1592 static void *read_object(struct repository *r,
1593                          const struct object_id *oid,
1594                          enum object_type *type,
1595                          unsigned long *size)
1596 {
1597         struct object_info oi = OBJECT_INFO_INIT;
1598         void *content;
1599         oi.typep = type;
1600         oi.sizep = size;
1601         oi.contentp = &content;
1602
1603         if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1604                 return NULL;
1605         return content;
1606 }
1607
1608 void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
1609                    enum object_type *final_type, unsigned long *final_size)
1610 {
1611         struct pack_window *w_curs = NULL;
1612         off_t curpos = obj_offset;
1613         void *data = NULL;
1614         unsigned long size;
1615         enum object_type type;
1616         struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1617         struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1618         int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1619         int base_from_cache = 0;
1620
1621         write_pack_access_log(p, obj_offset);
1622
1623         /* PHASE 1: drill down to the innermost base object */
1624         for (;;) {
1625                 off_t base_offset;
1626                 int i;
1627                 struct delta_base_cache_entry *ent;
1628
1629                 ent = get_delta_base_cache_entry(p, curpos);
1630                 if (ent) {
1631                         type = ent->type;
1632                         data = ent->data;
1633                         size = ent->size;
1634                         detach_delta_base_cache_entry(ent);
1635                         base_from_cache = 1;
1636                         break;
1637                 }
1638
1639                 if (do_check_packed_object_crc && p->index_version > 1) {
1640                         struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1641                         off_t len = revidx[1].offset - obj_offset;
1642                         if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1643                                 struct object_id oid;
1644                                 nth_packed_object_oid(&oid, p, revidx->nr);
1645                                 error("bad packed object CRC for %s",
1646                                       oid_to_hex(&oid));
1647                                 mark_bad_packed_object(p, oid.hash);
1648                                 data = NULL;
1649                                 goto out;
1650                         }
1651                 }
1652
1653                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1654                 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1655                         break;
1656
1657                 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1658                 if (!base_offset) {
1659                         error("failed to validate delta base reference "
1660                               "at offset %"PRIuMAX" from %s",
1661                               (uintmax_t)curpos, p->pack_name);
1662                         /* bail to phase 2, in hopes of recovery */
1663                         data = NULL;
1664                         break;
1665                 }
1666
1667                 /* push object, proceed to base */
1668                 if (delta_stack_nr >= delta_stack_alloc
1669                     && delta_stack == small_delta_stack) {
1670                         delta_stack_alloc = alloc_nr(delta_stack_nr);
1671                         ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1672                         memcpy(delta_stack, small_delta_stack,
1673                                sizeof(*delta_stack)*delta_stack_nr);
1674                 } else {
1675                         ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1676                 }
1677                 i = delta_stack_nr++;
1678                 delta_stack[i].obj_offset = obj_offset;
1679                 delta_stack[i].curpos = curpos;
1680                 delta_stack[i].size = size;
1681
1682                 curpos = obj_offset = base_offset;
1683         }
1684
1685         /* PHASE 2: handle the base */
1686         switch (type) {
1687         case OBJ_OFS_DELTA:
1688         case OBJ_REF_DELTA:
1689                 if (data)
1690                         BUG("unpack_entry: left loop at a valid delta");
1691                 break;
1692         case OBJ_COMMIT:
1693         case OBJ_TREE:
1694         case OBJ_BLOB:
1695         case OBJ_TAG:
1696                 if (!base_from_cache)
1697                         data = unpack_compressed_entry(p, &w_curs, curpos, size);
1698                 break;
1699         default:
1700                 data = NULL;
1701                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1702                       type, (uintmax_t)obj_offset, p->pack_name);
1703         }
1704
1705         /* PHASE 3: apply deltas in order */
1706
1707         /* invariants:
1708          *   'data' holds the base data, or NULL if there was corruption
1709          */
1710         while (delta_stack_nr) {
1711                 void *delta_data;
1712                 void *base = data;
1713                 void *external_base = NULL;
1714                 unsigned long delta_size, base_size = size;
1715                 int i;
1716
1717                 data = NULL;
1718
1719                 if (base)
1720                         add_delta_base_cache(p, obj_offset, base, base_size, type);
1721
1722                 if (!base) {
1723                         /*
1724                          * We're probably in deep shit, but let's try to fetch
1725                          * the required base anyway from another pack or loose.
1726                          * This is costly but should happen only in the presence
1727                          * of a corrupted pack, and is better than failing outright.
1728                          */
1729                         struct revindex_entry *revidx;
1730                         struct object_id base_oid;
1731                         revidx = find_pack_revindex(p, obj_offset);
1732                         if (revidx) {
1733                                 nth_packed_object_oid(&base_oid, p, revidx->nr);
1734                                 error("failed to read delta base object %s"
1735                                       " at offset %"PRIuMAX" from %s",
1736                                       oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1737                                       p->pack_name);
1738                                 mark_bad_packed_object(p, base_oid.hash);
1739                                 base = read_object(r, &base_oid, &type, &base_size);
1740                                 external_base = base;
1741                         }
1742                 }
1743
1744                 i = --delta_stack_nr;
1745                 obj_offset = delta_stack[i].obj_offset;
1746                 curpos = delta_stack[i].curpos;
1747                 delta_size = delta_stack[i].size;
1748
1749                 if (!base)
1750                         continue;
1751
1752                 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1753
1754                 if (!delta_data) {
1755                         error("failed to unpack compressed delta "
1756                               "at offset %"PRIuMAX" from %s",
1757                               (uintmax_t)curpos, p->pack_name);
1758                         data = NULL;
1759                         free(external_base);
1760                         continue;
1761                 }
1762
1763                 data = patch_delta(base, base_size,
1764                                    delta_data, delta_size,
1765                                    &size);
1766
1767                 /*
1768                  * We could not apply the delta; warn the user, but keep going.
1769                  * Our failure will be noticed either in the next iteration of
1770                  * the loop, or if this is the final delta, in the caller when
1771                  * we return NULL. Those code paths will take care of making
1772                  * a more explicit warning and retrying with another copy of
1773                  * the object.
1774                  */
1775                 if (!data)
1776                         error("failed to apply delta");
1777
1778                 free(delta_data);
1779                 free(external_base);
1780         }
1781
1782         if (final_type)
1783                 *final_type = type;
1784         if (final_size)
1785                 *final_size = size;
1786
1787 out:
1788         unuse_pack(&w_curs);
1789
1790         if (delta_stack != small_delta_stack)
1791                 free(delta_stack);
1792
1793         return data;
1794 }
1795
1796 int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1797 {
1798         const unsigned char *index_fanout = p->index_data;
1799         const unsigned char *index_lookup;
1800         const unsigned int hashsz = the_hash_algo->rawsz;
1801         int index_lookup_width;
1802
1803         if (!index_fanout)
1804                 BUG("bsearch_pack called without a valid pack-index");
1805
1806         index_lookup = index_fanout + 4 * 256;
1807         if (p->index_version == 1) {
1808                 index_lookup_width = hashsz + 4;
1809                 index_lookup += 4;
1810         } else {
1811                 index_lookup_width = hashsz;
1812                 index_fanout += 8;
1813                 index_lookup += 8;
1814         }
1815
1816         return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1817                             index_lookup, index_lookup_width, result);
1818 }
1819
1820 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1821                                             uint32_t n)
1822 {
1823         const unsigned char *index = p->index_data;
1824         const unsigned int hashsz = the_hash_algo->rawsz;
1825         if (!index) {
1826                 if (open_pack_index(p))
1827                         return NULL;
1828                 index = p->index_data;
1829         }
1830         if (n >= p->num_objects)
1831                 return NULL;
1832         index += 4 * 256;
1833         if (p->index_version == 1) {
1834                 return index + (hashsz + 4) * n + 4;
1835         } else {
1836                 index += 8;
1837                 return index + hashsz * n;
1838         }
1839 }
1840
1841 const struct object_id *nth_packed_object_oid(struct object_id *oid,
1842                                               struct packed_git *p,
1843                                               uint32_t n)
1844 {
1845         const unsigned char *hash = nth_packed_object_sha1(p, n);
1846         if (!hash)
1847                 return NULL;
1848         hashcpy(oid->hash, hash);
1849         return oid;
1850 }
1851
1852 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1853 {
1854         const unsigned char *ptr = vptr;
1855         const unsigned char *start = p->index_data;
1856         const unsigned char *end = start + p->index_size;
1857         if (ptr < start)
1858                 die(_("offset before start of pack index for %s (corrupt index?)"),
1859                     p->pack_name);
1860         /* No need to check for underflow; .idx files must be at least 8 bytes */
1861         if (ptr >= end - 8)
1862                 die(_("offset beyond end of pack index for %s (truncated index?)"),
1863                     p->pack_name);
1864 }
1865
1866 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1867 {
1868         const unsigned char *index = p->index_data;
1869         const unsigned int hashsz = the_hash_algo->rawsz;
1870         index += 4 * 256;
1871         if (p->index_version == 1) {
1872                 return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
1873         } else {
1874                 uint32_t off;
1875                 index += 8 + p->num_objects * (hashsz + 4);
1876                 off = ntohl(*((uint32_t *)(index + 4 * n)));
1877                 if (!(off & 0x80000000))
1878                         return off;
1879                 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1880                 check_pack_index_ptr(p, index);
1881                 return get_be64(index);
1882         }
1883 }
1884
1885 off_t find_pack_entry_one(const unsigned char *sha1,
1886                                   struct packed_git *p)
1887 {
1888         const unsigned char *index = p->index_data;
1889         struct object_id oid;
1890         uint32_t result;
1891
1892         if (!index) {
1893                 if (open_pack_index(p))
1894                         return 0;
1895         }
1896
1897         hashcpy(oid.hash, sha1);
1898         if (bsearch_pack(&oid, p, &result))
1899                 return nth_packed_object_offset(p, result);
1900         return 0;
1901 }
1902
1903 int is_pack_valid(struct packed_git *p)
1904 {
1905         /* An already open pack is known to be valid. */
1906         if (p->pack_fd != -1)
1907                 return 1;
1908
1909         /* If the pack has one window completely covering the
1910          * file size, the pack is known to be valid even if
1911          * the descriptor is not currently open.
1912          */
1913         if (p->windows) {
1914                 struct pack_window *w = p->windows;
1915
1916                 if (!w->offset && w->len == p->pack_size)
1917                         return 1;
1918         }
1919
1920         /* Force the pack to open to prove its valid. */
1921         return !open_packed_git(p);
1922 }
1923
1924 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1925                                   struct packed_git *packs)
1926 {
1927         struct packed_git *p;
1928
1929         for (p = packs; p; p = p->next) {
1930                 if (find_pack_entry_one(sha1, p))
1931                         return p;
1932         }
1933         return NULL;
1934
1935 }
1936
1937 static int fill_pack_entry(const struct object_id *oid,
1938                            struct pack_entry *e,
1939                            struct packed_git *p)
1940 {
1941         off_t offset;
1942
1943         if (p->num_bad_objects) {
1944                 unsigned i;
1945                 for (i = 0; i < p->num_bad_objects; i++)
1946                         if (hasheq(oid->hash,
1947                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1948                                 return 0;
1949         }
1950
1951         offset = find_pack_entry_one(oid->hash, p);
1952         if (!offset)
1953                 return 0;
1954
1955         /*
1956          * We are about to tell the caller where they can locate the
1957          * requested object.  We better make sure the packfile is
1958          * still here and can be accessed before supplying that
1959          * answer, as it may have been deleted since the index was
1960          * loaded!
1961          */
1962         if (!is_pack_valid(p))
1963                 return 0;
1964         e->offset = offset;
1965         e->p = p;
1966         return 1;
1967 }
1968
1969 int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
1970 {
1971         struct list_head *pos;
1972         struct multi_pack_index *m;
1973
1974         prepare_packed_git(r);
1975         if (!r->objects->packed_git && !r->objects->multi_pack_index)
1976                 return 0;
1977
1978         for (m = r->objects->multi_pack_index; m; m = m->next) {
1979                 if (fill_midx_entry(oid, e, m))
1980                         return 1;
1981         }
1982
1983         list_for_each(pos, &r->objects->packed_git_mru) {
1984                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
1985                 if (fill_pack_entry(oid, e, p)) {
1986                         list_move(&p->mru, &r->objects->packed_git_mru);
1987                         return 1;
1988                 }
1989         }
1990         return 0;
1991 }
1992
1993 int has_object_pack(const struct object_id *oid)
1994 {
1995         struct pack_entry e;
1996         return find_pack_entry(the_repository, oid, &e);
1997 }
1998
1999 int has_pack_index(const unsigned char *sha1)
2000 {
2001         struct stat st;
2002         if (stat(sha1_pack_index_name(sha1), &st))
2003                 return 0;
2004         return 1;
2005 }
2006
2007 int for_each_object_in_pack(struct packed_git *p,
2008                             each_packed_object_fn cb, void *data,
2009                             enum for_each_object_flags flags)
2010 {
2011         uint32_t i;
2012         int r = 0;
2013
2014         if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2015                 load_pack_revindex(p);
2016
2017         for (i = 0; i < p->num_objects; i++) {
2018                 uint32_t pos;
2019                 struct object_id oid;
2020
2021                 if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2022                         pos = p->revindex[i].nr;
2023                 else
2024                         pos = i;
2025
2026                 if (!nth_packed_object_oid(&oid, p, pos))
2027                         return error("unable to get sha1 of object %u in %s",
2028                                      pos, p->pack_name);
2029
2030                 r = cb(&oid, p, pos, data);
2031                 if (r)
2032                         break;
2033         }
2034         return r;
2035 }
2036
2037 int for_each_packed_object(each_packed_object_fn cb, void *data,
2038                            enum for_each_object_flags flags)
2039 {
2040         struct packed_git *p;
2041         int r = 0;
2042         int pack_errors = 0;
2043
2044         prepare_packed_git(the_repository);
2045         for (p = get_all_packs(the_repository); p; p = p->next) {
2046                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2047                         continue;
2048                 if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
2049                     !p->pack_promisor)
2050                         continue;
2051                 if (open_pack_index(p)) {
2052                         pack_errors = 1;
2053                         continue;
2054                 }
2055                 r = for_each_object_in_pack(p, cb, data, flags);
2056                 if (r)
2057                         break;
2058         }
2059         return r ? r : pack_errors;
2060 }
2061
2062 static int add_promisor_object(const struct object_id *oid,
2063                                struct packed_git *pack,
2064                                uint32_t pos,
2065                                void *set_)
2066 {
2067         struct oidset *set = set_;
2068         struct object *obj = parse_object(the_repository, oid);
2069         if (!obj)
2070                 return 1;
2071
2072         oidset_insert(set, oid);
2073
2074         /*
2075          * If this is a tree, commit, or tag, the objects it refers
2076          * to are also promisor objects. (Blobs refer to no objects->)
2077          */
2078         if (obj->type == OBJ_TREE) {
2079                 struct tree *tree = (struct tree *)obj;
2080                 struct tree_desc desc;
2081                 struct name_entry entry;
2082                 if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
2083                         /*
2084                          * Error messages are given when packs are
2085                          * verified, so do not print any here.
2086                          */
2087                         return 0;
2088                 while (tree_entry_gently(&desc, &entry))
2089                         oidset_insert(set, entry.oid);
2090         } else if (obj->type == OBJ_COMMIT) {
2091                 struct commit *commit = (struct commit *) obj;
2092                 struct commit_list *parents = commit->parents;
2093
2094                 oidset_insert(set, get_commit_tree_oid(commit));
2095                 for (; parents; parents = parents->next)
2096                         oidset_insert(set, &parents->item->object.oid);
2097         } else if (obj->type == OBJ_TAG) {
2098                 struct tag *tag = (struct tag *) obj;
2099                 oidset_insert(set, &tag->tagged->oid);
2100         }
2101         return 0;
2102 }
2103
2104 int is_promisor_object(const struct object_id *oid)
2105 {
2106         static struct oidset promisor_objects;
2107         static int promisor_objects_prepared;
2108
2109         if (!promisor_objects_prepared) {
2110                 if (repository_format_partial_clone) {
2111                         for_each_packed_object(add_promisor_object,
2112                                                &promisor_objects,
2113                                                FOR_EACH_OBJECT_PROMISOR_ONLY);
2114                 }
2115                 promisor_objects_prepared = 1;
2116         }
2117         return oidset_contains(&promisor_objects, oid);
2118 }