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