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

   1 #include "cache.h"
   2 #include "list.h"
   3 #include "pack.h"
   4 #include "repository.h"
   5 #include "dir.h"
   6 #include "mergesort.h"
   7 #include "packfile.h"
   8 #include "delta.h"
   9 #include "streaming.h"
  10 #include "sha1-lookup.h"
  11 #include "commit.h"
  12 #include "object.h"
  13 #include "tag.h"
  14 #include "tree-walk.h"
  15 #include "tree.h"
  16 #include "object-store.h"
  17 #include "midx.h"
  18 #include "commit-graph.h"
  19 #include "promisor-remote.h"
  20
  21 char *odb_pack_name(struct strbuf *buf,
  22                     const unsigned char *hash,
  23                     const char *ext)
  24 {
  25         strbuf_reset(buf);
  26         strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
  27                     hash_to_hex(hash), ext);
  28         return buf->buf;
  29 }
  30
  31 char *sha1_pack_name(const unsigned char *sha1)
  32 {
  33         static struct strbuf buf = STRBUF_INIT;
  34         return odb_pack_name(&buf, sha1, "pack");
  35 }
  36
  37 char *sha1_pack_index_name(const unsigned char *sha1)
  38 {
  39         static struct strbuf buf = STRBUF_INIT;
  40         return odb_pack_name(&buf, sha1, "idx");
  41 }
  42
  43 static unsigned int pack_used_ctr;
  44 static unsigned int pack_mmap_calls;
  45 static unsigned int peak_pack_open_windows;
  46 static unsigned int pack_open_windows;
  47 static unsigned int pack_open_fds;
  48 static unsigned int pack_max_fds;
  49 static size_t peak_pack_mapped;
  50 static size_t pack_mapped;
  51
  52 #define SZ_FMT PRIuMAX
  53 static inline uintmax_t sz_fmt(size_t s) { return s; }
  54
  55 void pack_report(void)
  56 {
  57         fprintf(stderr,
  58                 "pack_report: getpagesize()            = %10" SZ_FMT "\n"
  59                 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
  60                 "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
  61                 sz_fmt(getpagesize()),
  62                 sz_fmt(packed_git_window_size),
  63                 sz_fmt(packed_git_limit));
  64         fprintf(stderr,
  65                 "pack_report: pack_used_ctr            = %10u\n"
  66                 "pack_report: pack_mmap_calls          = %10u\n"
  67                 "pack_report: pack_open_windows        = %10u / %10u\n"
  68                 "pack_report: pack_mapped              = "
  69                         "%10" SZ_FMT " / %10" SZ_FMT "\n",
  70                 pack_used_ctr,
  71                 pack_mmap_calls,
  72                 pack_open_windows, peak_pack_open_windows,
  73                 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
  74 }
  75
  76 /*
  77  * Open and mmap the index file at path, perform a couple of
  78  * consistency checks, then record its information to p.  Return 0 on
  79  * success.
  80  */
  81 static int check_packed_git_idx(const char *path, struct packed_git *p)
  82 {
  83         void *idx_map;
  84         size_t idx_size;
  85         int fd = git_open(path), ret;
  86         struct stat st;
  87         const unsigned int hashsz = the_hash_algo->rawsz;
  88
  89         if (fd < 0)
  90                 return -1;
  91         if (fstat(fd, &st)) {
  92                 close(fd);
  93                 return -1;
  94         }
  95         idx_size = xsize_t(st.st_size);
  96         if (idx_size < 4 * 256 + hashsz + hashsz) {
  97                 close(fd);
  98                 return error("index file %s is too small", path);
  99         }
 100         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 101         close(fd);
 102
 103         ret = load_idx(path, hashsz, idx_map, idx_size, p);
 104
 105         if (ret)
 106                 munmap(idx_map, idx_size);
 107
 108         return ret;
 109 }
 110
 111 int load_idx(const char *path, const unsigned int hashsz, void *idx_map,
 112              size_t idx_size, struct packed_git *p)
 113 {
 114         struct pack_idx_header *hdr = idx_map;
 115         uint32_t version, nr, i, *index;
 116
 117         if (idx_size < 4 * 256 + hashsz + hashsz)
 118                 return error("index file %s is too small", path);
 119         if (idx_map == NULL)
 120                 return error("empty data");
 121
 122         if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 123                 version = ntohl(hdr->idx_version);
 124                 if (version < 2 || version > 2)
 125                         return error("index file %s is version %"PRIu32
 126                                      " and is not supported by this binary"
 127                                      " (try upgrading GIT to a newer version)",
 128                                      path, version);
 129         } else
 130                 version = 1;
 131
 132         nr = 0;
 133         index = idx_map;
 134         if (version > 1)
 135                 index += 2;  /* skip index header */
 136         for (i = 0; i < 256; i++) {
 137                 uint32_t n = ntohl(index[i]);
 138                 if (n < nr)
 139                         return error("non-monotonic index %s", path);
 140                 nr = n;
 141         }
 142
 143         if (version == 1) {
 144                 /*
 145                  * Total size:
 146                  *  - 256 index entries 4 bytes each
 147                  *  - 24-byte entries * nr (object ID + 4-byte offset)
 148                  *  - hash of the packfile
 149                  *  - file checksum
 150                  */
 151                 if (idx_size != 4 * 256 + nr * (hashsz + 4) + hashsz + hashsz)
 152                         return error("wrong index v1 file size in %s", path);
 153         } else if (version == 2) {
 154                 /*
 155                  * Minimum size:
 156                  *  - 8 bytes of header
 157                  *  - 256 index entries 4 bytes each
 158                  *  - object ID entry * nr
 159                  *  - 4-byte crc entry * nr
 160                  *  - 4-byte offset entry * nr
 161                  *  - hash of the packfile
 162                  *  - file checksum
 163                  * And after the 4-byte offset table might be a
 164                  * variable sized table containing 8-byte entries
 165                  * for offsets larger than 2^31.
 166                  */
 167                 unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
 168                 unsigned long max_size = min_size;
 169                 if (nr)
 170                         max_size += (nr - 1)*8;
 171                 if (idx_size < min_size || idx_size > max_size)
 172                         return error("wrong index v2 file size in %s", path);
 173                 if (idx_size != min_size &&
 174                     /*
 175                      * make sure we can deal with large pack offsets.
 176                      * 31-bit signed offset won't be enough, neither
 177                      * 32-bit unsigned one will be.
 178                      */
 179                     (sizeof(off_t) <= 4))
 180                         return error("pack too large for current definition of off_t in %s", path);
 181         }
 182
 183         p->index_version = version;
 184         p->index_data = idx_map;
 185         p->index_size = idx_size;
 186         p->num_objects = nr;
 187         return 0;
 188 }
 189
 190 int open_pack_index(struct packed_git *p)
 191 {
 192         char *idx_name;
 193         size_t len;
 194         int ret;
 195
 196         if (p->index_data)
 197                 return 0;
 198
 199         if (!strip_suffix(p->pack_name, ".pack", &len))
 200                 BUG("pack_name does not end in .pack");
 201         idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 202         ret = check_packed_git_idx(idx_name, p);
 203         free(idx_name);
 204         return ret;
 205 }
 206
 207 uint32_t get_pack_fanout(struct packed_git *p, uint32_t value)
 208 {
 209         const uint32_t *level1_ofs = p->index_data;
 210
 211         if (!level1_ofs) {
 212                 if (open_pack_index(p))
 213                         return 0;
 214                 level1_ofs = p->index_data;
 215         }
 216
 217         if (p->index_version > 1) {
 218                 level1_ofs += 2;
 219         }
 220
 221         return ntohl(level1_ofs[value]);
 222 }
 223
 224 static struct packed_git *alloc_packed_git(int extra)
 225 {
 226         struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
 227         memset(p, 0, sizeof(*p));
 228         p->pack_fd = -1;
 229         return p;
 230 }
 231
 232 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 233 {
 234         const char *path = sha1_pack_name(sha1);
 235         size_t alloc = st_add(strlen(path), 1);
 236         struct packed_git *p = alloc_packed_git(alloc);
 237
 238         memcpy(p->pack_name, path, alloc); /* includes NUL */
 239         hashcpy(p->hash, sha1);
 240         if (check_packed_git_idx(idx_path, p)) {
 241                 free(p);
 242                 return NULL;
 243         }
 244
 245         return p;
 246 }
 247
 248 static void scan_windows(struct packed_git *p,
 249         struct packed_git **lru_p,
 250         struct pack_window **lru_w,
 251         struct pack_window **lru_l)
 252 {
 253         struct pack_window *w, *w_l;
 254
 255         for (w_l = NULL, w = p->windows; w; w = w->next) {
 256                 if (!w->inuse_cnt) {
 257                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 258                                 *lru_p = p;
 259                                 *lru_w = w;
 260                                 *lru_l = w_l;
 261                         }
 262                 }
 263                 w_l = w;
 264         }
 265 }
 266
 267 static int unuse_one_window(struct packed_git *current)
 268 {
 269         struct packed_git *p, *lru_p = NULL;
 270         struct pack_window *lru_w = NULL, *lru_l = NULL;
 271
 272         if (current)
 273                 scan_windows(current, &lru_p, &lru_w, &lru_l);
 274         for (p = the_repository->objects->packed_git; p; p = p->next)
 275                 scan_windows(p, &lru_p, &lru_w, &lru_l);
 276         if (lru_p) {
 277                 munmap(lru_w->base, lru_w->len);
 278                 pack_mapped -= lru_w->len;
 279                 if (lru_l)
 280                         lru_l->next = lru_w->next;
 281                 else
 282                         lru_p->windows = lru_w->next;
 283                 free(lru_w);
 284                 pack_open_windows--;
 285                 return 1;
 286         }
 287         return 0;
 288 }
 289
 290 void close_pack_windows(struct packed_git *p)
 291 {
 292         while (p->windows) {
 293                 struct pack_window *w = p->windows;
 294
 295                 if (w->inuse_cnt)
 296                         die("pack '%s' still has open windows to it",
 297                             p->pack_name);
 298                 munmap(w->base, w->len);
 299                 pack_mapped -= w->len;
 300                 pack_open_windows--;
 301                 p->windows = w->next;
 302                 free(w);
 303         }
 304 }
 305
 306 int close_pack_fd(struct packed_git *p)
 307 {
 308         if (p->pack_fd < 0)
 309                 return 0;
 310
 311         close(p->pack_fd);
 312         pack_open_fds--;
 313         p->pack_fd = -1;
 314
 315         return 1;
 316 }
 317
 318 void close_pack_index(struct packed_git *p)
 319 {
 320         if (p->index_data) {
 321                 munmap((void *)p->index_data, p->index_size);
 322                 p->index_data = NULL;
 323         }
 324 }
 325
 326 void close_pack(struct packed_git *p)
 327 {
 328         close_pack_windows(p);
 329         close_pack_fd(p);
 330         close_pack_index(p);
 331 }
 332
 333 void close_object_store(struct raw_object_store *o)
 334 {
 335         struct packed_git *p;
 336
 337         for (p = o->packed_git; p; p = p->next)
 338                 if (p->do_not_close)
 339                         BUG("want to close pack marked 'do-not-close'");
 340                 else
 341                         close_pack(p);
 342
 343         if (o->multi_pack_index) {
 344                 close_midx(o->multi_pack_index);
 345                 o->multi_pack_index = NULL;
 346         }
 347
 348         close_commit_graph(o);
 349 }
 350
 351 void unlink_pack_path(const char *pack_name, int force_delete)
 352 {
 353         static const char *exts[] = {".pack", ".idx", ".keep", ".bitmap", ".promisor"};
 354         int i;
 355         struct strbuf buf = STRBUF_INIT;
 356         size_t plen;
 357
 358         strbuf_addstr(&buf, pack_name);
 359         strip_suffix_mem(buf.buf, &buf.len, ".pack");
 360         plen = buf.len;
 361
 362         if (!force_delete) {
 363                 strbuf_addstr(&buf, ".keep");
 364                 if (!access(buf.buf, F_OK)) {
 365                         strbuf_release(&buf);
 366                         return;
 367                 }
 368         }
 369
 370         for (i = 0; i < ARRAY_SIZE(exts); i++) {
 371                 strbuf_setlen(&buf, plen);
 372                 strbuf_addstr(&buf, exts[i]);
 373                 unlink(buf.buf);
 374         }
 375
 376         strbuf_release(&buf);
 377 }
 378
 379 /*
 380  * The LRU pack is the one with the oldest MRU window, preferring packs
 381  * with no used windows, or the oldest mtime if it has no windows allocated.
 382  */
 383 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 384 {
 385         struct pack_window *w, *this_mru_w;
 386         int has_windows_inuse = 0;
 387
 388         /*
 389          * Reject this pack if it has windows and the previously selected
 390          * one does not.  If this pack does not have windows, reject
 391          * it if the pack file is newer than the previously selected one.
 392          */
 393         if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 394                 return;
 395
 396         for (w = this_mru_w = p->windows; w; w = w->next) {
 397                 /*
 398                  * Reject this pack if any of its windows are in use,
 399                  * but the previously selected pack did not have any
 400                  * inuse windows.  Otherwise, record that this pack
 401                  * has windows in use.
 402                  */
 403                 if (w->inuse_cnt) {
 404                         if (*accept_windows_inuse)
 405                                 has_windows_inuse = 1;
 406                         else
 407                                 return;
 408                 }
 409
 410                 if (w->last_used > this_mru_w->last_used)
 411                         this_mru_w = w;
 412
 413                 /*
 414                  * Reject this pack if it has windows that have been
 415                  * used more recently than the previously selected pack.
 416                  * If the previously selected pack had windows inuse and
 417                  * we have not encountered a window in this pack that is
 418                  * inuse, skip this check since we prefer a pack with no
 419                  * inuse windows to one that has inuse windows.
 420                  */
 421                 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 422                     this_mru_w->last_used > (*mru_w)->last_used)
 423                         return;
 424         }
 425
 426         /*
 427          * Select this pack.
 428          */
 429         *mru_w = this_mru_w;
 430         *lru_p = p;
 431         *accept_windows_inuse = has_windows_inuse;
 432 }
 433
 434 static int close_one_pack(void)
 435 {
 436         struct packed_git *p, *lru_p = NULL;
 437         struct pack_window *mru_w = NULL;
 438         int accept_windows_inuse = 1;
 439
 440         for (p = the_repository->objects->packed_git; p; p = p->next) {
 441                 if (p->pack_fd == -1)
 442                         continue;
 443                 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 444         }
 445
 446         if (lru_p)
 447                 return close_pack_fd(lru_p);
 448
 449         return 0;
 450 }
 451
 452 static unsigned int get_max_fd_limit(void)
 453 {
 454 #ifdef RLIMIT_NOFILE
 455         {
 456                 struct rlimit lim;
 457
 458                 if (!getrlimit(RLIMIT_NOFILE, &lim))
 459                         return lim.rlim_cur;
 460         }
 461 #endif
 462
 463 #ifdef _SC_OPEN_MAX
 464         {
 465                 long open_max = sysconf(_SC_OPEN_MAX);
 466                 if (0 < open_max)
 467                         return open_max;
 468                 /*
 469                  * Otherwise, we got -1 for one of the two
 470                  * reasons:
 471                  *
 472                  * (1) sysconf() did not understand _SC_OPEN_MAX
 473                  *     and signaled an error with -1; or
 474                  * (2) sysconf() said there is no limit.
 475                  *
 476                  * We _could_ clear errno before calling sysconf() to
 477                  * tell these two cases apart and return a huge number
 478                  * in the latter case to let the caller cap it to a
 479                  * value that is not so selfish, but letting the
 480                  * fallback OPEN_MAX codepath take care of these cases
 481                  * is a lot simpler.
 482                  */
 483         }
 484 #endif
 485
 486 #ifdef OPEN_MAX
 487         return OPEN_MAX;
 488 #else
 489         return 1; /* see the caller ;-) */
 490 #endif
 491 }
 492
 493 const char *pack_basename(struct packed_git *p)
 494 {
 495         const char *ret = strrchr(p->pack_name, '/');
 496         if (ret)
 497                 ret = ret + 1; /* skip past slash */
 498         else
 499                 ret = p->pack_name; /* we only have a base */
 500         return ret;
 501 }
 502
 503 /*
 504  * Do not call this directly as this leaks p->pack_fd on error return;
 505  * call open_packed_git() instead.
 506  */
 507 static int open_packed_git_1(struct packed_git *p)
 508 {
 509         struct stat st;
 510         struct pack_header hdr;
 511         unsigned char hash[GIT_MAX_RAWSZ];
 512         unsigned char *idx_hash;
 513         long fd_flag;
 514         ssize_t read_result;
 515         const unsigned hashsz = the_hash_algo->rawsz;
 516
 517         if (!p->index_data) {
 518                 struct multi_pack_index *m;
 519                 const char *pack_name = pack_basename(p);
 520
 521                 for (m = the_repository->objects->multi_pack_index;
 522                      m; m = m->next) {
 523                         if (midx_contains_pack(m, pack_name))
 524                                 break;
 525                 }
 526
 527                 if (!m && open_pack_index(p))
 528                         return error("packfile %s index unavailable", p->pack_name);
 529         }
 530
 531         if (!pack_max_fds) {
 532                 unsigned int max_fds = get_max_fd_limit();
 533
 534                 /* Save 3 for stdin/stdout/stderr, 22 for work */
 535                 if (25 < max_fds)
 536                         pack_max_fds = max_fds - 25;
 537                 else
 538                         pack_max_fds = 1;
 539         }
 540
 541         while (pack_max_fds <= pack_open_fds && close_one_pack())
 542                 ; /* nothing */
 543
 544         p->pack_fd = git_open(p->pack_name);
 545         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 546                 return -1;
 547         pack_open_fds++;
 548
 549         /* If we created the struct before we had the pack we lack size. */
 550         if (!p->pack_size) {
 551                 if (!S_ISREG(st.st_mode))
 552                         return error("packfile %s not a regular file", p->pack_name);
 553                 p->pack_size = st.st_size;
 554         } else if (p->pack_size != st.st_size)
 555                 return error("packfile %s size changed", p->pack_name);
 556
 557         /* We leave these file descriptors open with sliding mmap;
 558          * there is no point keeping them open across exec(), though.
 559          */
 560         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 561         if (fd_flag < 0)
 562                 return error("cannot determine file descriptor flags");
 563         fd_flag |= FD_CLOEXEC;
 564         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 565                 return error("cannot set FD_CLOEXEC");
 566
 567         /* Verify we recognize this pack file format. */
 568         read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
 569         if (read_result < 0)
 570                 return error_errno("error reading from %s", p->pack_name);
 571         if (read_result != sizeof(hdr))
 572                 return error("file %s is far too short to be a packfile", p->pack_name);
 573         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 574                 return error("file %s is not a GIT packfile", p->pack_name);
 575         if (!pack_version_ok(hdr.hdr_version))
 576                 return error("packfile %s is version %"PRIu32" and not"
 577                         " supported (try upgrading GIT to a newer version)",
 578                         p->pack_name, ntohl(hdr.hdr_version));
 579
 580         /* Skip index checking if in multi-pack-index */
 581         if (!p->index_data)
 582                 return 0;
 583
 584         /* Verify the pack matches its index. */
 585         if (p->num_objects != ntohl(hdr.hdr_entries))
 586                 return error("packfile %s claims to have %"PRIu32" objects"
 587                              " while index indicates %"PRIu32" objects",
 588                              p->pack_name, ntohl(hdr.hdr_entries),
 589                              p->num_objects);
 590         if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
 591                 return error("end of packfile %s is unavailable", p->pack_name);
 592         read_result = read_in_full(p->pack_fd, hash, hashsz);
 593         if (read_result < 0)
 594                 return error_errno("error reading from %s", p->pack_name);
 595         if (read_result != hashsz)
 596                 return error("packfile %s signature is unavailable", p->pack_name);
 597         idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
 598         if (!hasheq(hash, idx_hash))
 599                 return error("packfile %s does not match index", p->pack_name);
 600         return 0;
 601 }
 602
 603 static int open_packed_git(struct packed_git *p)
 604 {
 605         if (!open_packed_git_1(p))
 606                 return 0;
 607         close_pack_fd(p);
 608         return -1;
 609 }
 610
 611 static int in_window(struct pack_window *win, off_t offset)
 612 {
 613         /* We must promise at least one full hash after the
 614          * offset is available from this window, otherwise the offset
 615          * is not actually in this window and a different window (which
 616          * has that one hash excess) must be used.  This is to support
 617          * the object header and delta base parsing routines below.
 618          */
 619         off_t win_off = win->offset;
 620         return win_off <= offset
 621                 && (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 622 }
 623
 624 unsigned char *use_pack(struct packed_git *p,
 625                 struct pack_window **w_cursor,
 626                 off_t offset,
 627                 unsigned long *left)
 628 {
 629         struct pack_window *win = *w_cursor;
 630
 631         /* Since packfiles end in a hash of their content and it's
 632          * pointless to ask for an offset into the middle of that
 633          * hash, and the in_window function above wouldn't match
 634          * don't allow an offset too close to the end of the file.
 635          */
 636         if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 637                 die("packfile %s cannot be accessed", p->pack_name);
 638         if (offset > (p->pack_size - the_hash_algo->rawsz))
 639                 die("offset beyond end of packfile (truncated pack?)");
 640         if (offset < 0)
 641                 die(_("offset before end of packfile (broken .idx?)"));
 642
 643         if (!win || !in_window(win, offset)) {
 644                 if (win)
 645                         win->inuse_cnt--;
 646                 for (win = p->windows; win; win = win->next) {
 647                         if (in_window(win, offset))
 648                                 break;
 649                 }
 650                 if (!win) {
 651                         size_t window_align = packed_git_window_size / 2;
 652                         off_t len;
 653
 654                         if (p->pack_fd == -1 && open_packed_git(p))
 655                                 die("packfile %s cannot be accessed", p->pack_name);
 656
 657                         win = xcalloc(1, sizeof(*win));
 658                         win->offset = (offset / window_align) * window_align;
 659                         len = p->pack_size - win->offset;
 660                         if (len > packed_git_window_size)
 661                                 len = packed_git_window_size;
 662                         win->len = (size_t)len;
 663                         pack_mapped += win->len;
 664                         while (packed_git_limit < pack_mapped
 665                                 && unuse_one_window(p))
 666                                 ; /* nothing */
 667                         win->base = xmmap_gently(NULL, win->len,
 668                                 PROT_READ, MAP_PRIVATE,
 669                                 p->pack_fd, win->offset);
 670                         if (win->base == MAP_FAILED)
 671                                 die_errno("packfile %s cannot be mapped",
 672                                           p->pack_name);
 673                         if (!win->offset && win->len == p->pack_size
 674                                 && !p->do_not_close)
 675                                 close_pack_fd(p);
 676                         pack_mmap_calls++;
 677                         pack_open_windows++;
 678                         if (pack_mapped > peak_pack_mapped)
 679                                 peak_pack_mapped = pack_mapped;
 680                         if (pack_open_windows > peak_pack_open_windows)
 681                                 peak_pack_open_windows = pack_open_windows;
 682                         win->next = p->windows;
 683                         p->windows = win;
 684                 }
 685         }
 686         if (win != *w_cursor) {
 687                 win->last_used = pack_used_ctr++;
 688                 win->inuse_cnt++;
 689                 *w_cursor = win;
 690         }
 691         offset -= win->offset;
 692         if (left)
 693                 *left = win->len - xsize_t(offset);
 694         return win->base + offset;
 695 }
 696
 697 void unuse_pack(struct pack_window **w_cursor)
 698 {
 699         struct pack_window *w = *w_cursor;
 700         if (w) {
 701                 w->inuse_cnt--;
 702                 *w_cursor = NULL;
 703         }
 704 }
 705
 706 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 707 {
 708         struct stat st;
 709         size_t alloc;
 710         struct packed_git *p;
 711
 712         /*
 713          * Make sure a corresponding .pack file exists and that
 714          * the index looks sane.
 715          */
 716         if (!strip_suffix_mem(path, &path_len, ".idx"))
 717                 return NULL;
 718
 719         /*
 720          * ".promisor" is long enough to hold any suffix we're adding (and
 721          * the use xsnprintf double-checks that)
 722          */
 723         alloc = st_add3(path_len, strlen(".promisor"), 1);
 724         p = alloc_packed_git(alloc);
 725         memcpy(p->pack_name, path, path_len);
 726
 727         xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
 728         if (!access(p->pack_name, F_OK))
 729                 p->pack_keep = 1;
 730
 731         xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
 732         if (!access(p->pack_name, F_OK))
 733                 p->pack_promisor = 1;
 734
 735         xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
 736         if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 737                 free(p);
 738                 return NULL;
 739         }
 740
 741         /* ok, it looks sane as far as we can check without
 742          * actually mapping the pack file.
 743          */
 744         p->pack_size = st.st_size;
 745         p->pack_local = local;
 746         p->mtime = st.st_mtime;
 747         if (path_len < the_hash_algo->hexsz ||
 748             get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->hash))
 749                 hashclr(p->hash);
 750         return p;
 751 }
 752
 753 void install_packed_git(struct repository *r, struct packed_git *pack)
 754 {
 755         if (pack->pack_fd != -1)
 756                 pack_open_fds++;
 757
 758         pack->next = r->objects->packed_git;
 759         r->objects->packed_git = pack;
 760 }
 761
 762 void (*report_garbage)(unsigned seen_bits, const char *path);
 763
 764 static void report_helper(const struct string_list *list,
 765                           int seen_bits, int first, int last)
 766 {
 767         if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
 768                 return;
 769
 770         for (; first < last; first++)
 771                 report_garbage(seen_bits, list->items[first].string);
 772 }
 773
 774 static void report_pack_garbage(struct string_list *list)
 775 {
 776         int i, baselen = -1, first = 0, seen_bits = 0;
 777
 778         if (!report_garbage)
 779                 return;
 780
 781         string_list_sort(list);
 782
 783         for (i = 0; i < list->nr; i++) {
 784                 const char *path = list->items[i].string;
 785                 if (baselen != -1 &&
 786                     strncmp(path, list->items[first].string, baselen)) {
 787                         report_helper(list, seen_bits, first, i);
 788                         baselen = -1;
 789                         seen_bits = 0;
 790                 }
 791                 if (baselen == -1) {
 792                         const char *dot = strrchr(path, '.');
 793                         if (!dot) {
 794                                 report_garbage(PACKDIR_FILE_GARBAGE, path);
 795                                 continue;
 796                         }
 797                         baselen = dot - path + 1;
 798                         first = i;
 799                 }
 800                 if (!strcmp(path + baselen, "pack"))
 801                         seen_bits |= 1;
 802                 else if (!strcmp(path + baselen, "idx"))
 803                         seen_bits |= 2;
 804         }
 805         report_helper(list, seen_bits, first, list->nr);
 806 }
 807
 808 void for_each_file_in_pack_dir(const char *objdir,
 809                                each_file_in_pack_dir_fn fn,
 810                                void *data)
 811 {
 812         struct strbuf path = STRBUF_INIT;
 813         size_t dirnamelen;
 814         DIR *dir;
 815         struct dirent *de;
 816
 817         strbuf_addstr(&path, objdir);
 818         strbuf_addstr(&path, "/pack");
 819         dir = opendir(path.buf);
 820         if (!dir) {
 821                 if (errno != ENOENT)
 822                         error_errno("unable to open object pack directory: %s",
 823                                     path.buf);
 824                 strbuf_release(&path);
 825                 return;
 826         }
 827         strbuf_addch(&path, '/');
 828         dirnamelen = path.len;
 829         while ((de = readdir(dir)) != NULL) {
 830                 if (is_dot_or_dotdot(de->d_name))
 831                         continue;
 832
 833                 strbuf_setlen(&path, dirnamelen);
 834                 strbuf_addstr(&path, de->d_name);
 835
 836                 fn(path.buf, path.len, de->d_name, data);
 837         }
 838
 839         closedir(dir);
 840         strbuf_release(&path);
 841 }
 842
 843 struct prepare_pack_data {
 844         struct repository *r;
 845         struct string_list *garbage;
 846         int local;
 847         struct multi_pack_index *m;
 848 };
 849
 850 static void prepare_pack(const char *full_name, size_t full_name_len,
 851                          const char *file_name, void *_data)
 852 {
 853         struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
 854         struct packed_git *p;
 855         size_t base_len = full_name_len;
 856
 857         if (strip_suffix_mem(full_name, &base_len, ".idx") &&
 858             !(data->m && midx_contains_pack(data->m, file_name))) {
 859                 /* Don't reopen a pack we already have. */
 860                 for (p = data->r->objects->packed_git; p; p = p->next) {
 861                         size_t len;
 862                         if (strip_suffix(p->pack_name, ".pack", &len) &&
 863                             len == base_len &&
 864                             !memcmp(p->pack_name, full_name, len))
 865                                 break;
 866                 }
 867
 868                 if (!p) {
 869                         p = add_packed_git(full_name, full_name_len, data->local);
 870                         if (p)
 871                                 install_packed_git(data->r, p);
 872                 }
 873         }
 874
 875         if (!report_garbage)
 876                 return;
 877
 878         if (!strcmp(file_name, "multi-pack-index"))
 879                 return;
 880         if (ends_with(file_name, ".idx") ||
 881             ends_with(file_name, ".pack") ||
 882             ends_with(file_name, ".bitmap") ||
 883             ends_with(file_name, ".keep") ||
 884             ends_with(file_name, ".promisor"))
 885                 string_list_append(data->garbage, full_name);
 886         else
 887                 report_garbage(PACKDIR_FILE_GARBAGE, full_name);
 888 }
 889
 890 static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
 891 {
 892         struct prepare_pack_data data;
 893         struct string_list garbage = STRING_LIST_INIT_DUP;
 894
 895         data.m = r->objects->multi_pack_index;
 896
 897         /* look for the multi-pack-index for this object directory */
 898         while (data.m && strcmp(data.m->object_dir, objdir))
 899                 data.m = data.m->next;
 900
 901         data.r = r;
 902         data.garbage = &garbage;
 903         data.local = local;
 904
 905         for_each_file_in_pack_dir(objdir, prepare_pack, &data);
 906
 907         report_pack_garbage(data.garbage);
 908         string_list_clear(data.garbage, 0);
 909 }
 910
 911 static void prepare_packed_git(struct repository *r);
 912 /*
 913  * Give a fast, rough count of the number of objects in the repository. This
 914  * ignores loose objects completely. If you have a lot of them, then either
 915  * you should repack because your performance will be awful, or they are
 916  * all unreachable objects about to be pruned, in which case they're not really
 917  * interesting as a measure of repo size in the first place.
 918  */
 919 unsigned long repo_approximate_object_count(struct repository *r)
 920 {
 921         if (!r->objects->approximate_object_count_valid) {
 922                 unsigned long count;
 923                 struct multi_pack_index *m;
 924                 struct packed_git *p;
 925
 926                 prepare_packed_git(r);
 927                 count = 0;
 928                 for (m = get_multi_pack_index(r); m; m = m->next)
 929                         count += m->num_objects;
 930                 for (p = r->objects->packed_git; p; p = p->next) {
 931                         if (open_pack_index(p))
 932                                 continue;
 933                         count += p->num_objects;
 934                 }
 935                 r->objects->approximate_object_count = count;
 936         }
 937         return r->objects->approximate_object_count;
 938 }
 939
 940 static void *get_next_packed_git(const void *p)
 941 {
 942         return ((const struct packed_git *)p)->next;
 943 }
 944
 945 static void set_next_packed_git(void *p, void *next)
 946 {
 947         ((struct packed_git *)p)->next = next;
 948 }
 949
 950 static int sort_pack(const void *a_, const void *b_)
 951 {
 952         const struct packed_git *a = a_;
 953         const struct packed_git *b = b_;
 954         int st;
 955
 956         /*
 957          * Local packs tend to contain objects specific to our
 958          * variant of the project than remote ones.  In addition,
 959          * remote ones could be on a network mounted filesystem.
 960          * Favor local ones for these reasons.
 961          */
 962         st = a->pack_local - b->pack_local;
 963         if (st)
 964                 return -st;
 965
 966         /*
 967          * Younger packs tend to contain more recent objects,
 968          * and more recent objects tend to get accessed more
 969          * often.
 970          */
 971         if (a->mtime < b->mtime)
 972                 return 1;
 973         else if (a->mtime == b->mtime)
 974                 return 0;
 975         return -1;
 976 }
 977
 978 static void rearrange_packed_git(struct repository *r)
 979 {
 980         r->objects->packed_git = llist_mergesort(
 981                 r->objects->packed_git, get_next_packed_git,
 982                 set_next_packed_git, sort_pack);
 983 }
 984
 985 static void prepare_packed_git_mru(struct repository *r)
 986 {
 987         struct packed_git *p;
 988
 989         INIT_LIST_HEAD(&r->objects->packed_git_mru);
 990
 991         for (p = r->objects->packed_git; p; p = p->next)
 992                 list_add_tail(&p->mru, &r->objects->packed_git_mru);
 993 }
 994
 995 static void prepare_packed_git(struct repository *r)
 996 {
 997         struct object_directory *odb;
 998
 999         if (r->objects->packed_git_initialized)
1000                 return;
1001
1002         prepare_alt_odb(r);
1003         for (odb = r->objects->odb; odb; odb = odb->next) {
1004                 int local = (odb == r->objects->odb);
1005                 prepare_multi_pack_index_one(r, odb->path, local);
1006                 prepare_packed_git_one(r, odb->path, local);
1007         }
1008         rearrange_packed_git(r);
1009
1010         prepare_packed_git_mru(r);
1011         r->objects->packed_git_initialized = 1;
1012 }
1013
1014 void reprepare_packed_git(struct repository *r)
1015 {
1016         struct object_directory *odb;
1017
1018         for (odb = r->objects->odb; odb; odb = odb->next)
1019                 odb_clear_loose_cache(odb);
1020
1021         r->objects->approximate_object_count_valid = 0;
1022         r->objects->packed_git_initialized = 0;
1023         prepare_packed_git(r);
1024 }
1025
1026 struct packed_git *get_packed_git(struct repository *r)
1027 {
1028         prepare_packed_git(r);
1029         return r->objects->packed_git;
1030 }
1031
1032 struct multi_pack_index *get_multi_pack_index(struct repository *r)
1033 {
1034         prepare_packed_git(r);
1035         return r->objects->multi_pack_index;
1036 }
1037
1038 struct packed_git *get_all_packs(struct repository *r)
1039 {
1040         struct multi_pack_index *m;
1041
1042         prepare_packed_git(r);
1043         for (m = r->objects->multi_pack_index; m; m = m->next) {
1044                 uint32_t i;
1045                 for (i = 0; i < m->num_packs; i++)
1046                         prepare_midx_pack(r, m, i);
1047         }
1048
1049         return r->objects->packed_git;
1050 }
1051
1052 struct list_head *get_packed_git_mru(struct repository *r)
1053 {
1054         prepare_packed_git(r);
1055         return &r->objects->packed_git_mru;
1056 }
1057
1058 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1059                 unsigned long len, enum object_type *type, unsigned long *sizep)
1060 {
1061         unsigned shift;
1062         unsigned long size, c;
1063         unsigned long used = 0;
1064
1065         c = buf[used++];
1066         *type = (c >> 4) & 7;
1067         size = c & 15;
1068         shift = 4;
1069         while (c & 0x80) {
1070                 if (len <= used || bitsizeof(long) <= shift) {
1071                         error("bad object header");
1072                         size = used = 0;
1073                         break;
1074                 }
1075                 c = buf[used++];
1076                 size += (c & 0x7f) << shift;
1077                 shift += 7;
1078         }
1079         *sizep = size;
1080         return used;
1081 }
1082
1083 unsigned long get_size_from_delta(struct packed_git *p,
1084                                   struct pack_window **w_curs,
1085                                   off_t curpos)
1086 {
1087         const unsigned char *data;
1088         unsigned char delta_head[20], *in;
1089         git_zstream stream;
1090         int st;
1091
1092         memset(&stream, 0, sizeof(stream));
1093         stream.next_out = delta_head;
1094         stream.avail_out = sizeof(delta_head);
1095
1096         git_inflate_init(&stream);
1097         do {
1098                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1099                 stream.next_in = in;
1100                 st = git_inflate(&stream, Z_FINISH);
1101                 curpos += stream.next_in - in;
1102         } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1103                  stream.total_out < sizeof(delta_head));
1104         git_inflate_end(&stream);
1105         if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1106                 error("delta data unpack-initial failed");
1107                 return 0;
1108         }
1109
1110         /* Examine the initial part of the delta to figure out
1111          * the result size.
1112          */
1113         data = delta_head;
1114
1115         /* ignore base size */
1116         get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1117
1118         /* Read the result size */
1119         return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1120 }
1121
1122 int unpack_object_header(struct packed_git *p,
1123                          struct pack_window **w_curs,
1124                          off_t *curpos,
1125                          unsigned long *sizep)
1126 {
1127         unsigned char *base;
1128         unsigned long left;
1129         unsigned long used;
1130         enum object_type type;
1131
1132         /* use_pack() assures us we have [base, base + 20) available
1133          * as a range that we can look at.  (Its actually the hash
1134          * size that is assured.)  With our object header encoding
1135          * the maximum deflated object size is 2^137, which is just
1136          * insane, so we know won't exceed what we have been given.
1137          */
1138         base = use_pack(p, w_curs, *curpos, &left);
1139         used = unpack_object_header_buffer(base, left, &type, sizep);
1140         if (!used) {
1141                 type = OBJ_BAD;
1142         } else
1143                 *curpos += used;
1144
1145         return type;
1146 }
1147
1148 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1149 {
1150         unsigned i;
1151         const unsigned hashsz = the_hash_algo->rawsz;
1152         for (i = 0; i < p->num_bad_objects; i++)
1153                 if (hasheq(sha1, p->bad_object_sha1 + hashsz * i))
1154                         return;
1155         p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1156                                       st_mult(GIT_MAX_RAWSZ,
1157                                               st_add(p->num_bad_objects, 1)));
1158         hashcpy(p->bad_object_sha1 + hashsz * p->num_bad_objects, sha1);
1159         p->num_bad_objects++;
1160 }
1161
1162 const struct packed_git *has_packed_and_bad(struct repository *r,
1163                                             const unsigned char *sha1)
1164 {
1165         struct packed_git *p;
1166         unsigned i;
1167
1168         for (p = r->objects->packed_git; p; p = p->next)
1169                 for (i = 0; i < p->num_bad_objects; i++)
1170                         if (hasheq(sha1,
1171                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1172                                 return p;
1173         return NULL;
1174 }
1175
1176 static off_t get_delta_base(struct packed_git *p,
1177                                     struct pack_window **w_curs,
1178                                     off_t *curpos,
1179                                     enum object_type type,
1180                                     off_t delta_obj_offset)
1181 {
1182         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1183         off_t base_offset;
1184
1185         /* use_pack() assured us we have [base_info, base_info + 20)
1186          * as a range that we can look at without walking off the
1187          * end of the mapped window.  Its actually the hash size
1188          * that is assured.  An OFS_DELTA longer than the hash size
1189          * is stupid, as then a REF_DELTA would be smaller to store.
1190          */
1191         if (type == OBJ_OFS_DELTA) {
1192                 unsigned used = 0;
1193                 unsigned char c = base_info[used++];
1194                 base_offset = c & 127;
1195                 while (c & 128) {
1196                         base_offset += 1;
1197                         if (!base_offset || MSB(base_offset, 7))
1198                                 return 0;  /* overflow */
1199                         c = base_info[used++];
1200                         base_offset = (base_offset << 7) + (c & 127);
1201                 }
1202                 base_offset = delta_obj_offset - base_offset;
1203                 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1204                         return 0;  /* out of bound */
1205                 *curpos += used;
1206         } else if (type == OBJ_REF_DELTA) {
1207                 /* The base entry _must_ be in the same pack */
1208                 base_offset = find_pack_entry_one(base_info, p);
1209                 *curpos += the_hash_algo->rawsz;
1210         } else
1211                 die("I am totally screwed");
1212         return base_offset;
1213 }
1214
1215 /*
1216  * Like get_delta_base above, but we return the sha1 instead of the pack
1217  * offset. This means it is cheaper for REF deltas (we do not have to do
1218  * the final object lookup), but more expensive for OFS deltas (we
1219  * have to load the revidx to convert the offset back into a sha1).
1220  */
1221 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1222                                                 struct pack_window **w_curs,
1223                                                 off_t curpos,
1224                                                 enum object_type type,
1225                                                 off_t delta_obj_offset)
1226 {
1227         if (type == OBJ_REF_DELTA) {
1228                 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1229                 return base;
1230         } else if (type == OBJ_OFS_DELTA) {
1231                 struct revindex_entry *revidx;
1232                 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1233                                                    type, delta_obj_offset);
1234
1235                 if (!base_offset)
1236                         return NULL;
1237
1238                 revidx = find_pack_revindex(p, base_offset);
1239                 if (!revidx)
1240                         return NULL;
1241
1242                 return nth_packed_object_sha1(p, revidx->nr);
1243         } else
1244                 return NULL;
1245 }
1246
1247 static int retry_bad_packed_offset(struct repository *r,
1248                                    struct packed_git *p,
1249                                    off_t obj_offset)
1250 {
1251         int type;
1252         struct revindex_entry *revidx;
1253         struct object_id oid;
1254         revidx = find_pack_revindex(p, obj_offset);
1255         if (!revidx)
1256                 return OBJ_BAD;
1257         nth_packed_object_oid(&oid, p, revidx->nr);
1258         mark_bad_packed_object(p, oid.hash);
1259         type = oid_object_info(r, &oid, NULL);
1260         if (type <= OBJ_NONE)
1261                 return OBJ_BAD;
1262         return type;
1263 }
1264
1265 #define POI_STACK_PREALLOC 64
1266
1267 static enum object_type packed_to_object_type(struct repository *r,
1268                                               struct packed_git *p,
1269                                               off_t obj_offset,
1270                                               enum object_type type,
1271                                               struct pack_window **w_curs,
1272                                               off_t curpos)
1273 {
1274         off_t small_poi_stack[POI_STACK_PREALLOC];
1275         off_t *poi_stack = small_poi_stack;
1276         int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1277
1278         while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1279                 off_t base_offset;
1280                 unsigned long size;
1281                 /* Push the object we're going to leave behind */
1282                 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1283                         poi_stack_alloc = alloc_nr(poi_stack_nr);
1284                         ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1285                         COPY_ARRAY(poi_stack, small_poi_stack, poi_stack_nr);
1286                 } else {
1287                         ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1288                 }
1289                 poi_stack[poi_stack_nr++] = obj_offset;
1290                 /* If parsing the base offset fails, just unwind */
1291                 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1292                 if (!base_offset)
1293                         goto unwind;
1294                 curpos = obj_offset = base_offset;
1295                 type = unpack_object_header(p, w_curs, &curpos, &size);
1296                 if (type <= OBJ_NONE) {
1297                         /* If getting the base itself fails, we first
1298                          * retry the base, otherwise unwind */
1299                         type = retry_bad_packed_offset(r, p, base_offset);
1300                         if (type > OBJ_NONE)
1301                                 goto out;
1302                         goto unwind;
1303                 }
1304         }
1305
1306         switch (type) {
1307         case OBJ_BAD:
1308         case OBJ_COMMIT:
1309         case OBJ_TREE:
1310         case OBJ_BLOB:
1311         case OBJ_TAG:
1312                 break;
1313         default:
1314                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1315                       type, (uintmax_t)obj_offset, p->pack_name);
1316                 type = OBJ_BAD;
1317         }
1318
1319 out:
1320         if (poi_stack != small_poi_stack)
1321                 free(poi_stack);
1322         return type;
1323
1324 unwind:
1325         while (poi_stack_nr) {
1326                 obj_offset = poi_stack[--poi_stack_nr];
1327                 type = retry_bad_packed_offset(r, p, obj_offset);
1328                 if (type > OBJ_NONE)
1329                         goto out;
1330         }
1331         type = OBJ_BAD;
1332         goto out;
1333 }
1334
1335 static struct hashmap delta_base_cache;
1336 static size_t delta_base_cached;
1337
1338 static LIST_HEAD(delta_base_cache_lru);
1339
1340 struct delta_base_cache_key {
1341         struct packed_git *p;
1342         off_t base_offset;
1343 };
1344
1345 struct delta_base_cache_entry {
1346         struct hashmap_entry ent;
1347         struct delta_base_cache_key key;
1348         struct list_head lru;
1349         void *data;
1350         unsigned long size;
1351         enum object_type type;
1352 };
1353
1354 static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1355 {
1356         unsigned int hash;
1357
1358         hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1359         hash += (hash >> 8) + (hash >> 16);
1360         return hash;
1361 }
1362
1363 static struct delta_base_cache_entry *
1364 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1365 {
1366         struct hashmap_entry entry, *e;
1367         struct delta_base_cache_key key;
1368
1369         if (!delta_base_cache.cmpfn)
1370                 return NULL;
1371
1372         hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1373         key.p = p;
1374         key.base_offset = base_offset;
1375         e = hashmap_get(&delta_base_cache, &entry, &key);
1376         return e ? container_of(e, struct delta_base_cache_entry, ent) : NULL;
1377 }
1378
1379 static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
1380                                    const struct delta_base_cache_key *b)
1381 {
1382         return a->p == b->p && a->base_offset == b->base_offset;
1383 }
1384
1385 static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
1386                                      const struct hashmap_entry *va,
1387                                      const struct hashmap_entry *vb,
1388                                      const void *vkey)
1389 {
1390         const struct delta_base_cache_entry *a, *b;
1391         const struct delta_base_cache_key *key = vkey;
1392
1393         a = container_of(va, const struct delta_base_cache_entry, ent);
1394         b = container_of(vb, const struct delta_base_cache_entry, ent);
1395
1396         if (key)
1397                 return !delta_base_cache_key_eq(&a->key, key);
1398         else
1399                 return !delta_base_cache_key_eq(&a->key, &b->key);
1400 }
1401
1402 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1403 {
1404         return !!get_delta_base_cache_entry(p, base_offset);
1405 }
1406
1407 /*
1408  * Remove the entry from the cache, but do _not_ free the associated
1409  * entry data. The caller takes ownership of the "data" buffer, and
1410  * should copy out any fields it wants before detaching.
1411  */
1412 static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1413 {
1414         hashmap_remove(&delta_base_cache, &ent->ent, &ent->key);
1415         list_del(&ent->lru);
1416         delta_base_cached -= ent->size;
1417         free(ent);
1418 }
1419
1420 static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
1421                                    off_t base_offset, unsigned long *base_size,
1422                                    enum object_type *type)
1423 {
1424         struct delta_base_cache_entry *ent;
1425
1426         ent = get_delta_base_cache_entry(p, base_offset);
1427         if (!ent)
1428                 return unpack_entry(r, p, base_offset, type, base_size);
1429
1430         if (type)
1431                 *type = ent->type;
1432         if (base_size)
1433                 *base_size = ent->size;
1434         return xmemdupz(ent->data, ent->size);
1435 }
1436
1437 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1438 {
1439         free(ent->data);
1440         detach_delta_base_cache_entry(ent);
1441 }
1442
1443 void clear_delta_base_cache(void)
1444 {
1445         struct list_head *lru, *tmp;
1446         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1447                 struct delta_base_cache_entry *entry =
1448                         list_entry(lru, struct delta_base_cache_entry, lru);
1449                 release_delta_base_cache(entry);
1450         }
1451 }
1452
1453 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1454         void *base, unsigned long base_size, enum object_type type)
1455 {
1456         struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1457         struct list_head *lru, *tmp;
1458
1459         delta_base_cached += base_size;
1460
1461         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1462                 struct delta_base_cache_entry *f =
1463                         list_entry(lru, struct delta_base_cache_entry, lru);
1464                 if (delta_base_cached <= delta_base_cache_limit)
1465                         break;
1466                 release_delta_base_cache(f);
1467         }
1468
1469         ent->key.p = p;
1470         ent->key.base_offset = base_offset;
1471         ent->type = type;
1472         ent->data = base;
1473         ent->size = base_size;
1474         list_add_tail(&ent->lru, &delta_base_cache_lru);
1475
1476         if (!delta_base_cache.cmpfn)
1477                 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1478         hashmap_entry_init(&ent->ent, pack_entry_hash(p, base_offset));
1479         hashmap_add(&delta_base_cache, &ent->ent);
1480 }
1481
1482 int packed_object_info(struct repository *r, struct packed_git *p,
1483                        off_t obj_offset, struct object_info *oi)
1484 {
1485         struct pack_window *w_curs = NULL;
1486         unsigned long size;
1487         off_t curpos = obj_offset;
1488         enum object_type type;
1489
1490         /*
1491          * We always get the representation type, but only convert it to
1492          * a "real" type later if the caller is interested.
1493          */
1494         if (oi->contentp) {
1495                 *oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
1496                                                       &type);
1497                 if (!*oi->contentp)
1498                         type = OBJ_BAD;
1499         } else {
1500                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1501         }
1502
1503         if (!oi->contentp && oi->sizep) {
1504                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1505                         off_t tmp_pos = curpos;
1506                         off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1507                                                            type, obj_offset);
1508                         if (!base_offset) {
1509                                 type = OBJ_BAD;
1510                                 goto out;
1511                         }
1512                         *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1513                         if (*oi->sizep == 0) {
1514                                 type = OBJ_BAD;
1515                                 goto out;
1516                         }
1517                 } else {
1518                         *oi->sizep = size;
1519                 }
1520         }
1521
1522         if (oi->disk_sizep) {
1523                 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1524                 *oi->disk_sizep = revidx[1].offset - obj_offset;
1525         }
1526
1527         if (oi->typep || oi->type_name) {
1528                 enum object_type ptot;
1529                 ptot = packed_to_object_type(r, p, obj_offset,
1530                                              type, &w_curs, curpos);
1531                 if (oi->typep)
1532                         *oi->typep = ptot;
1533                 if (oi->type_name) {
1534                         const char *tn = type_name(ptot);
1535                         if (tn)
1536                                 strbuf_addstr(oi->type_name, tn);
1537                 }
1538                 if (ptot < 0) {
1539                         type = OBJ_BAD;
1540                         goto out;
1541                 }
1542         }
1543
1544         if (oi->delta_base_sha1) {
1545                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1546                         const unsigned char *base;
1547
1548                         base = get_delta_base_sha1(p, &w_curs, curpos,
1549                                                    type, obj_offset);
1550                         if (!base) {
1551                                 type = OBJ_BAD;
1552                                 goto out;
1553                         }
1554
1555                         hashcpy(oi->delta_base_sha1, base);
1556                 } else
1557                         hashclr(oi->delta_base_sha1);
1558         }
1559
1560         oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1561                                                           OI_PACKED;
1562
1563 out:
1564         unuse_pack(&w_curs);
1565         return type;
1566 }
1567
1568 static void *unpack_compressed_entry(struct packed_git *p,
1569                                     struct pack_window **w_curs,
1570                                     off_t curpos,
1571                                     unsigned long size)
1572 {
1573         int st;
1574         git_zstream stream;
1575         unsigned char *buffer, *in;
1576
1577         buffer = xmallocz_gently(size);
1578         if (!buffer)
1579                 return NULL;
1580         memset(&stream, 0, sizeof(stream));
1581         stream.next_out = buffer;
1582         stream.avail_out = size + 1;
1583
1584         git_inflate_init(&stream);
1585         do {
1586                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1587                 stream.next_in = in;
1588                 st = git_inflate(&stream, Z_FINISH);
1589                 if (!stream.avail_out)
1590                         break; /* the payload is larger than it should be */
1591                 curpos += stream.next_in - in;
1592         } while (st == Z_OK || st == Z_BUF_ERROR);
1593         git_inflate_end(&stream);
1594         if ((st != Z_STREAM_END) || stream.total_out != size) {
1595                 free(buffer);
1596                 return NULL;
1597         }
1598
1599         /* versions of zlib can clobber unconsumed portion of outbuf */
1600         buffer[size] = '\0';
1601
1602         return buffer;
1603 }
1604
1605 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1606 {
1607         static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1608         trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1609                          p->pack_name, (uintmax_t)obj_offset);
1610 }
1611
1612 int do_check_packed_object_crc;
1613
1614 #define UNPACK_ENTRY_STACK_PREALLOC 64
1615 struct unpack_entry_stack_ent {
1616         off_t obj_offset;
1617         off_t curpos;
1618         unsigned long size;
1619 };
1620
1621 static void *read_object(struct repository *r,
1622                          const struct object_id *oid,
1623                          enum object_type *type,
1624                          unsigned long *size)
1625 {
1626         struct object_info oi = OBJECT_INFO_INIT;
1627         void *content;
1628         oi.typep = type;
1629         oi.sizep = size;
1630         oi.contentp = &content;
1631
1632         if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1633                 return NULL;
1634         return content;
1635 }
1636
1637 void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
1638                    enum object_type *final_type, unsigned long *final_size)
1639 {
1640         struct pack_window *w_curs = NULL;
1641         off_t curpos = obj_offset;
1642         void *data = NULL;
1643         unsigned long size;
1644         enum object_type type;
1645         struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1646         struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1647         int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1648         int base_from_cache = 0;
1649
1650         write_pack_access_log(p, obj_offset);
1651
1652         /* PHASE 1: drill down to the innermost base object */
1653         for (;;) {
1654                 off_t base_offset;
1655                 int i;
1656                 struct delta_base_cache_entry *ent;
1657
1658                 ent = get_delta_base_cache_entry(p, curpos);
1659                 if (ent) {
1660                         type = ent->type;
1661                         data = ent->data;
1662                         size = ent->size;
1663                         detach_delta_base_cache_entry(ent);
1664                         base_from_cache = 1;
1665                         break;
1666                 }
1667
1668                 if (do_check_packed_object_crc && p->index_version > 1) {
1669                         struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1670                         off_t len = revidx[1].offset - obj_offset;
1671                         if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1672                                 struct object_id oid;
1673                                 nth_packed_object_oid(&oid, p, revidx->nr);
1674                                 error("bad packed object CRC for %s",
1675                                       oid_to_hex(&oid));
1676                                 mark_bad_packed_object(p, oid.hash);
1677                                 data = NULL;
1678                                 goto out;
1679                         }
1680                 }
1681
1682                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1683                 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1684                         break;
1685
1686                 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1687                 if (!base_offset) {
1688                         error("failed to validate delta base reference "
1689                               "at offset %"PRIuMAX" from %s",
1690                               (uintmax_t)curpos, p->pack_name);
1691                         /* bail to phase 2, in hopes of recovery */
1692                         data = NULL;
1693                         break;
1694                 }
1695
1696                 /* push object, proceed to base */
1697                 if (delta_stack_nr >= delta_stack_alloc
1698                     && delta_stack == small_delta_stack) {
1699                         delta_stack_alloc = alloc_nr(delta_stack_nr);
1700                         ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1701                         COPY_ARRAY(delta_stack, small_delta_stack,
1702                                    delta_stack_nr);
1703                 } else {
1704                         ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1705                 }
1706                 i = delta_stack_nr++;
1707                 delta_stack[i].obj_offset = obj_offset;
1708                 delta_stack[i].curpos = curpos;
1709                 delta_stack[i].size = size;
1710
1711                 curpos = obj_offset = base_offset;
1712         }
1713
1714         /* PHASE 2: handle the base */
1715         switch (type) {
1716         case OBJ_OFS_DELTA:
1717         case OBJ_REF_DELTA:
1718                 if (data)
1719                         BUG("unpack_entry: left loop at a valid delta");
1720                 break;
1721         case OBJ_COMMIT:
1722         case OBJ_TREE:
1723         case OBJ_BLOB:
1724         case OBJ_TAG:
1725                 if (!base_from_cache)
1726                         data = unpack_compressed_entry(p, &w_curs, curpos, size);
1727                 break;
1728         default:
1729                 data = NULL;
1730                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1731                       type, (uintmax_t)obj_offset, p->pack_name);
1732         }
1733
1734         /* PHASE 3: apply deltas in order */
1735
1736         /* invariants:
1737          *   'data' holds the base data, or NULL if there was corruption
1738          */
1739         while (delta_stack_nr) {
1740                 void *delta_data;
1741                 void *base = data;
1742                 void *external_base = NULL;
1743                 unsigned long delta_size, base_size = size;
1744                 int i;
1745
1746                 data = NULL;
1747
1748                 if (base)
1749                         add_delta_base_cache(p, obj_offset, base, base_size, type);
1750
1751                 if (!base) {
1752                         /*
1753                          * We're probably in deep shit, but let's try to fetch
1754                          * the required base anyway from another pack or loose.
1755                          * This is costly but should happen only in the presence
1756                          * of a corrupted pack, and is better than failing outright.
1757                          */
1758                         struct revindex_entry *revidx;
1759                         struct object_id base_oid;
1760                         revidx = find_pack_revindex(p, obj_offset);
1761                         if (revidx) {
1762                                 nth_packed_object_oid(&base_oid, p, revidx->nr);
1763                                 error("failed to read delta base object %s"
1764                                       " at offset %"PRIuMAX" from %s",
1765                                       oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1766                                       p->pack_name);
1767                                 mark_bad_packed_object(p, base_oid.hash);
1768                                 base = read_object(r, &base_oid, &type, &base_size);
1769                                 external_base = base;
1770                         }
1771                 }
1772
1773                 i = --delta_stack_nr;
1774                 obj_offset = delta_stack[i].obj_offset;
1775                 curpos = delta_stack[i].curpos;
1776                 delta_size = delta_stack[i].size;
1777
1778                 if (!base)
1779                         continue;
1780
1781                 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1782
1783                 if (!delta_data) {
1784                         error("failed to unpack compressed delta "
1785                               "at offset %"PRIuMAX" from %s",
1786                               (uintmax_t)curpos, p->pack_name);
1787                         data = NULL;
1788                         free(external_base);
1789                         continue;
1790                 }
1791
1792                 data = patch_delta(base, base_size,
1793                                    delta_data, delta_size,
1794                                    &size);
1795
1796                 /*
1797                  * We could not apply the delta; warn the user, but keep going.
1798                  * Our failure will be noticed either in the next iteration of
1799                  * the loop, or if this is the final delta, in the caller when
1800                  * we return NULL. Those code paths will take care of making
1801                  * a more explicit warning and retrying with another copy of
1802                  * the object.
1803                  */
1804                 if (!data)
1805                         error("failed to apply delta");
1806
1807                 free(delta_data);
1808                 free(external_base);
1809         }
1810
1811         if (final_type)
1812                 *final_type = type;
1813         if (final_size)
1814                 *final_size = size;
1815
1816 out:
1817         unuse_pack(&w_curs);
1818
1819         if (delta_stack != small_delta_stack)
1820                 free(delta_stack);
1821
1822         return data;
1823 }
1824
1825 int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1826 {
1827         const unsigned char *index_fanout = p->index_data;
1828         const unsigned char *index_lookup;
1829         const unsigned int hashsz = the_hash_algo->rawsz;
1830         int index_lookup_width;
1831
1832         if (!index_fanout)
1833                 BUG("bsearch_pack called without a valid pack-index");
1834
1835         index_lookup = index_fanout + 4 * 256;
1836         if (p->index_version == 1) {
1837                 index_lookup_width = hashsz + 4;
1838                 index_lookup += 4;
1839         } else {
1840                 index_lookup_width = hashsz;
1841                 index_fanout += 8;
1842                 index_lookup += 8;
1843         }
1844
1845         return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1846                             index_lookup, index_lookup_width, result);
1847 }
1848
1849 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1850                                             uint32_t n)
1851 {
1852         const unsigned char *index = p->index_data;
1853         const unsigned int hashsz = the_hash_algo->rawsz;
1854         if (!index) {
1855                 if (open_pack_index(p))
1856                         return NULL;
1857                 index = p->index_data;
1858         }
1859         if (n >= p->num_objects)
1860                 return NULL;
1861         index += 4 * 256;
1862         if (p->index_version == 1) {
1863                 return index + (hashsz + 4) * n + 4;
1864         } else {
1865                 index += 8;
1866                 return index + hashsz * n;
1867         }
1868 }
1869
1870 const struct object_id *nth_packed_object_oid(struct object_id *oid,
1871                                               struct packed_git *p,
1872                                               uint32_t n)
1873 {
1874         const unsigned char *hash = nth_packed_object_sha1(p, n);
1875         if (!hash)
1876                 return NULL;
1877         hashcpy(oid->hash, hash);
1878         return oid;
1879 }
1880
1881 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1882 {
1883         const unsigned char *ptr = vptr;
1884         const unsigned char *start = p->index_data;
1885         const unsigned char *end = start + p->index_size;
1886         if (ptr < start)
1887                 die(_("offset before start of pack index for %s (corrupt index?)"),
1888                     p->pack_name);
1889         /* No need to check for underflow; .idx files must be at least 8 bytes */
1890         if (ptr >= end - 8)
1891                 die(_("offset beyond end of pack index for %s (truncated index?)"),
1892                     p->pack_name);
1893 }
1894
1895 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1896 {
1897         const unsigned char *index = p->index_data;
1898         const unsigned int hashsz = the_hash_algo->rawsz;
1899         index += 4 * 256;
1900         if (p->index_version == 1) {
1901                 return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
1902         } else {
1903                 uint32_t off;
1904                 index += 8 + p->num_objects * (hashsz + 4);
1905                 off = ntohl(*((uint32_t *)(index + 4 * n)));
1906                 if (!(off & 0x80000000))
1907                         return off;
1908                 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1909                 check_pack_index_ptr(p, index);
1910                 return get_be64(index);
1911         }
1912 }
1913
1914 off_t find_pack_entry_one(const unsigned char *sha1,
1915                                   struct packed_git *p)
1916 {
1917         const unsigned char *index = p->index_data;
1918         struct object_id oid;
1919         uint32_t result;
1920
1921         if (!index) {
1922                 if (open_pack_index(p))
1923                         return 0;
1924         }
1925
1926         hashcpy(oid.hash, sha1);
1927         if (bsearch_pack(&oid, p, &result))
1928                 return nth_packed_object_offset(p, result);
1929         return 0;
1930 }
1931
1932 int is_pack_valid(struct packed_git *p)
1933 {
1934         /* An already open pack is known to be valid. */
1935         if (p->pack_fd != -1)
1936                 return 1;
1937
1938         /* If the pack has one window completely covering the
1939          * file size, the pack is known to be valid even if
1940          * the descriptor is not currently open.
1941          */
1942         if (p->windows) {
1943                 struct pack_window *w = p->windows;
1944
1945                 if (!w->offset && w->len == p->pack_size)
1946                         return 1;
1947         }
1948
1949         /* Force the pack to open to prove its valid. */
1950         return !open_packed_git(p);
1951 }
1952
1953 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1954                                   struct packed_git *packs)
1955 {
1956         struct packed_git *p;
1957
1958         for (p = packs; p; p = p->next) {
1959                 if (find_pack_entry_one(sha1, p))
1960                         return p;
1961         }
1962         return NULL;
1963
1964 }
1965
1966 static int fill_pack_entry(const struct object_id *oid,
1967                            struct pack_entry *e,
1968                            struct packed_git *p)
1969 {
1970         off_t offset;
1971
1972         if (p->num_bad_objects) {
1973                 unsigned i;
1974                 for (i = 0; i < p->num_bad_objects; i++)
1975                         if (hasheq(oid->hash,
1976                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1977                                 return 0;
1978         }
1979
1980         offset = find_pack_entry_one(oid->hash, p);
1981         if (!offset)
1982                 return 0;
1983
1984         /*
1985          * We are about to tell the caller where they can locate the
1986          * requested object.  We better make sure the packfile is
1987          * still here and can be accessed before supplying that
1988          * answer, as it may have been deleted since the index was
1989          * loaded!
1990          */
1991         if (!is_pack_valid(p))
1992                 return 0;
1993         e->offset = offset;
1994         e->p = p;
1995         return 1;
1996 }
1997
1998 int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
1999 {
2000         struct list_head *pos;
2001         struct multi_pack_index *m;
2002
2003         prepare_packed_git(r);
2004         if (!r->objects->packed_git && !r->objects->multi_pack_index)
2005                 return 0;
2006
2007         for (m = r->objects->multi_pack_index; m; m = m->next) {
2008                 if (fill_midx_entry(r, oid, e, m))
2009                         return 1;
2010         }
2011
2012         list_for_each(pos, &r->objects->packed_git_mru) {
2013                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
2014                 if (!p->multi_pack_index && fill_pack_entry(oid, e, p)) {
2015                         list_move(&p->mru, &r->objects->packed_git_mru);
2016                         return 1;
2017                 }
2018         }
2019         return 0;
2020 }
2021
2022 int has_object_pack(const struct object_id *oid)
2023 {
2024         struct pack_entry e;
2025         return find_pack_entry(the_repository, oid, &e);
2026 }
2027
2028 int has_pack_index(const unsigned char *sha1)
2029 {
2030         struct stat st;
2031         if (stat(sha1_pack_index_name(sha1), &st))
2032                 return 0;
2033         return 1;
2034 }
2035
2036 int for_each_object_in_pack(struct packed_git *p,
2037                             each_packed_object_fn cb, void *data,
2038                             enum for_each_object_flags flags)
2039 {
2040         uint32_t i;
2041         int r = 0;
2042
2043         if (flags & FOR_EACH_OBJECT_PACK_ORDER) {
2044                 if (load_pack_revindex(p))
2045                         return -1;
2046         }
2047
2048         for (i = 0; i < p->num_objects; i++) {
2049                 uint32_t pos;
2050                 struct object_id oid;
2051
2052                 if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2053                         pos = p->revindex[i].nr;
2054                 else
2055                         pos = i;
2056
2057                 if (!nth_packed_object_oid(&oid, p, pos))
2058                         return error("unable to get sha1 of object %u in %s",
2059                                      pos, p->pack_name);
2060
2061                 r = cb(&oid, p, pos, data);
2062                 if (r)
2063                         break;
2064         }
2065         return r;
2066 }
2067
2068 int for_each_packed_object(each_packed_object_fn cb, void *data,
2069                            enum for_each_object_flags flags)
2070 {
2071         struct packed_git *p;
2072         int r = 0;
2073         int pack_errors = 0;
2074
2075         prepare_packed_git(the_repository);
2076         for (p = get_all_packs(the_repository); p; p = p->next) {
2077                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2078                         continue;
2079                 if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
2080                     !p->pack_promisor)
2081                         continue;
2082                 if (open_pack_index(p)) {
2083                         pack_errors = 1;
2084                         continue;
2085                 }
2086                 r = for_each_object_in_pack(p, cb, data, flags);
2087                 if (r)
2088                         break;
2089         }
2090         return r ? r : pack_errors;
2091 }
2092
2093 static int add_promisor_object(const struct object_id *oid,
2094                                struct packed_git *pack,
2095                                uint32_t pos,
2096                                void *set_)
2097 {
2098         struct oidset *set = set_;
2099         struct object *obj = parse_object(the_repository, oid);
2100         if (!obj)
2101                 return 1;
2102
2103         oidset_insert(set, oid);
2104
2105         /*
2106          * If this is a tree, commit, or tag, the objects it refers
2107          * to are also promisor objects. (Blobs refer to no objects->)
2108          */
2109         if (obj->type == OBJ_TREE) {
2110                 struct tree *tree = (struct tree *)obj;
2111                 struct tree_desc desc;
2112                 struct name_entry entry;
2113                 if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
2114                         /*
2115                          * Error messages are given when packs are
2116                          * verified, so do not print any here.
2117                          */
2118                         return 0;
2119                 while (tree_entry_gently(&desc, &entry))
2120                         oidset_insert(set, &entry.oid);
2121         } else if (obj->type == OBJ_COMMIT) {
2122                 struct commit *commit = (struct commit *) obj;
2123                 struct commit_list *parents = commit->parents;
2124
2125                 oidset_insert(set, get_commit_tree_oid(commit));
2126                 for (; parents; parents = parents->next)
2127                         oidset_insert(set, &parents->item->object.oid);
2128         } else if (obj->type == OBJ_TAG) {
2129                 struct tag *tag = (struct tag *) obj;
2130                 oidset_insert(set, get_tagged_oid(tag));
2131         }
2132         return 0;
2133 }
2134
2135 int is_promisor_object(const struct object_id *oid)
2136 {
2137         static struct oidset promisor_objects;
2138         static int promisor_objects_prepared;
2139
2140         if (!promisor_objects_prepared) {
2141                 if (has_promisor_remote()) {
2142                         for_each_packed_object(add_promisor_object,
2143                                                &promisor_objects,
2144                                                FOR_EACH_OBJECT_PROMISOR_ONLY);
2145                 }
2146                 promisor_objects_prepared = 1;
2147         }
2148         return oidset_contains(&promisor_objects, oid);
2149 }