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

   1 #include "cache.h"
   2 #include "list.h"
   3 #include "pack.h"
   4 #include "repository.h"
   5 #include "dir.h"
   6 #include "mergesort.h"
   7 #include "packfile.h"
   8 #include "delta.h"
   9 #include "list.h"
  10 #include "streaming.h"
  11 #include "sha1-lookup.h"
  12 #include "commit.h"
  13 #include "object.h"
  14 #include "tag.h"
  15 #include "tree-walk.h"
  16 #include "tree.h"
  17 #include "object-store.h"
  18 #include "midx.h"
  19 #include "commit-graph.h"
  20 #include "promisor-remote.h"
  21
  22 char *odb_pack_name(struct strbuf *buf,
  23                     const unsigned char *sha1,
  24                     const char *ext)
  25 {
  26         strbuf_reset(buf);
  27         strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
  28                     sha1_to_hex(sha1), ext);
  29         return buf->buf;
  30 }
  31
  32 char *sha1_pack_name(const unsigned char *sha1)
  33 {
  34         static struct strbuf buf = STRBUF_INIT;
  35         return odb_pack_name(&buf, sha1, "pack");
  36 }
  37
  38 char *sha1_pack_index_name(const unsigned char *sha1)
  39 {
  40         static struct strbuf buf = STRBUF_INIT;
  41         return odb_pack_name(&buf, sha1, "idx");
  42 }
  43
  44 static unsigned int pack_used_ctr;
  45 static unsigned int pack_mmap_calls;
  46 static unsigned int peak_pack_open_windows;
  47 static unsigned int pack_open_windows;
  48 static unsigned int pack_open_fds;
  49 static unsigned int pack_max_fds;
  50 static size_t peak_pack_mapped;
  51 static size_t pack_mapped;
  52
  53 #define SZ_FMT PRIuMAX
  54 static inline uintmax_t sz_fmt(size_t s) { return s; }
  55
  56 void pack_report(void)
  57 {
  58         fprintf(stderr,
  59                 "pack_report: getpagesize()            = %10" SZ_FMT "\n"
  60                 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
  61                 "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
  62                 sz_fmt(getpagesize()),
  63                 sz_fmt(packed_git_window_size),
  64                 sz_fmt(packed_git_limit));
  65         fprintf(stderr,
  66                 "pack_report: pack_used_ctr            = %10u\n"
  67                 "pack_report: pack_mmap_calls          = %10u\n"
  68                 "pack_report: pack_open_windows        = %10u / %10u\n"
  69                 "pack_report: pack_mapped              = "
  70                         "%10" SZ_FMT " / %10" SZ_FMT "\n",
  71                 pack_used_ctr,
  72                 pack_mmap_calls,
  73                 pack_open_windows, peak_pack_open_windows,
  74                 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
  75 }
  76
  77 /*
  78  * Open and mmap the index file at path, perform a couple of
  79  * consistency checks, then record its information to p.  Return 0 on
  80  * success.
  81  */
  82 static int check_packed_git_idx(const char *path, struct packed_git *p)
  83 {
  84         void *idx_map;
  85         size_t idx_size;
  86         int fd = git_open(path), ret;
  87         struct stat st;
  88         const unsigned int hashsz = the_hash_algo->rawsz;
  89
  90         if (fd < 0)
  91                 return -1;
  92         if (fstat(fd, &st)) {
  93                 close(fd);
  94                 return -1;
  95         }
  96         idx_size = xsize_t(st.st_size);
  97         if (idx_size < 4 * 256 + hashsz + hashsz) {
  98                 close(fd);
  99                 return error("index file %s is too small", path);
 100         }
 101         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
 102         close(fd);
 103
 104         ret = load_idx(path, hashsz, idx_map, idx_size, p);
 105
 106         if (ret)
 107                 munmap(idx_map, idx_size);
 108
 109         return ret;
 110 }
 111
 112 int load_idx(const char *path, const unsigned int hashsz, void *idx_map,
 113              size_t idx_size, struct packed_git *p)
 114 {
 115         struct pack_idx_header *hdr = idx_map;
 116         uint32_t version, nr, i, *index;
 117
 118         if (idx_size < 4 * 256 + hashsz + hashsz)
 119                 return error("index file %s is too small", path);
 120         if (idx_map == NULL)
 121                 return error("empty data");
 122
 123         if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
 124                 version = ntohl(hdr->idx_version);
 125                 if (version < 2 || version > 2)
 126                         return error("index file %s is version %"PRIu32
 127                                      " and is not supported by this binary"
 128                                      " (try upgrading GIT to a newer version)",
 129                                      path, version);
 130         } else
 131                 version = 1;
 132
 133         nr = 0;
 134         index = idx_map;
 135         if (version > 1)
 136                 index += 2;  /* skip index header */
 137         for (i = 0; i < 256; i++) {
 138                 uint32_t n = ntohl(index[i]);
 139                 if (n < nr)
 140                         return error("non-monotonic index %s", path);
 141                 nr = n;
 142         }
 143
 144         if (version == 1) {
 145                 /*
 146                  * Total size:
 147                  *  - 256 index entries 4 bytes each
 148                  *  - 24-byte entries * nr (object ID + 4-byte offset)
 149                  *  - hash of the packfile
 150                  *  - file checksum
 151                  */
 152                 if (idx_size != 4 * 256 + nr * (hashsz + 4) + hashsz + hashsz)
 153                         return error("wrong index v1 file size in %s", path);
 154         } else if (version == 2) {
 155                 /*
 156                  * Minimum size:
 157                  *  - 8 bytes of header
 158                  *  - 256 index entries 4 bytes each
 159                  *  - object ID entry * nr
 160                  *  - 4-byte crc entry * nr
 161                  *  - 4-byte offset entry * nr
 162                  *  - hash of the packfile
 163                  *  - file checksum
 164                  * And after the 4-byte offset table might be a
 165                  * variable sized table containing 8-byte entries
 166                  * for offsets larger than 2^31.
 167                  */
 168                 unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
 169                 unsigned long max_size = min_size;
 170                 if (nr)
 171                         max_size += (nr - 1)*8;
 172                 if (idx_size < min_size || idx_size > max_size)
 173                         return error("wrong index v2 file size in %s", path);
 174                 if (idx_size != min_size &&
 175                     /*
 176                      * make sure we can deal with large pack offsets.
 177                      * 31-bit signed offset won't be enough, neither
 178                      * 32-bit unsigned one will be.
 179                      */
 180                     (sizeof(off_t) <= 4))
 181                         return error("pack too large for current definition of off_t in %s", path);
 182         }
 183
 184         p->index_version = version;
 185         p->index_data = idx_map;
 186         p->index_size = idx_size;
 187         p->num_objects = nr;
 188         return 0;
 189 }
 190
 191 int open_pack_index(struct packed_git *p)
 192 {
 193         char *idx_name;
 194         size_t len;
 195         int ret;
 196
 197         if (p->index_data)
 198                 return 0;
 199
 200         if (!strip_suffix(p->pack_name, ".pack", &len))
 201                 BUG("pack_name does not end in .pack");
 202         idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
 203         ret = check_packed_git_idx(idx_name, p);
 204         free(idx_name);
 205         return ret;
 206 }
 207
 208 uint32_t get_pack_fanout(struct packed_git *p, uint32_t value)
 209 {
 210         const uint32_t *level1_ofs = p->index_data;
 211
 212         if (!level1_ofs) {
 213                 if (open_pack_index(p))
 214                         return 0;
 215                 level1_ofs = p->index_data;
 216         }
 217
 218         if (p->index_version > 1) {
 219                 level1_ofs += 2;
 220         }
 221
 222         return ntohl(level1_ofs[value]);
 223 }
 224
 225 static struct packed_git *alloc_packed_git(int extra)
 226 {
 227         struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
 228         memset(p, 0, sizeof(*p));
 229         p->pack_fd = -1;
 230         return p;
 231 }
 232
 233 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 234 {
 235         const char *path = sha1_pack_name(sha1);
 236         size_t alloc = st_add(strlen(path), 1);
 237         struct packed_git *p = alloc_packed_git(alloc);
 238
 239         memcpy(p->pack_name, path, alloc); /* includes NUL */
 240         hashcpy(p->hash, sha1);
 241         if (check_packed_git_idx(idx_path, p)) {
 242                 free(p);
 243                 return NULL;
 244         }
 245
 246         return p;
 247 }
 248
 249 static void scan_windows(struct packed_git *p,
 250         struct packed_git **lru_p,
 251         struct pack_window **lru_w,
 252         struct pack_window **lru_l)
 253 {
 254         struct pack_window *w, *w_l;
 255
 256         for (w_l = NULL, w = p->windows; w; w = w->next) {
 257                 if (!w->inuse_cnt) {
 258                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
 259                                 *lru_p = p;
 260                                 *lru_w = w;
 261                                 *lru_l = w_l;
 262                         }
 263                 }
 264                 w_l = w;
 265         }
 266 }
 267
 268 static int unuse_one_window(struct packed_git *current)
 269 {
 270         struct packed_git *p, *lru_p = NULL;
 271         struct pack_window *lru_w = NULL, *lru_l = NULL;
 272
 273         if (current)
 274                 scan_windows(current, &lru_p, &lru_w, &lru_l);
 275         for (p = the_repository->objects->packed_git; p; p = p->next)
 276                 scan_windows(p, &lru_p, &lru_w, &lru_l);
 277         if (lru_p) {
 278                 munmap(lru_w->base, lru_w->len);
 279                 pack_mapped -= lru_w->len;
 280                 if (lru_l)
 281                         lru_l->next = lru_w->next;
 282                 else
 283                         lru_p->windows = lru_w->next;
 284                 free(lru_w);
 285                 pack_open_windows--;
 286                 return 1;
 287         }
 288         return 0;
 289 }
 290
 291 void close_pack_windows(struct packed_git *p)
 292 {
 293         while (p->windows) {
 294                 struct pack_window *w = p->windows;
 295
 296                 if (w->inuse_cnt)
 297                         die("pack '%s' still has open windows to it",
 298                             p->pack_name);
 299                 munmap(w->base, w->len);
 300                 pack_mapped -= w->len;
 301                 pack_open_windows--;
 302                 p->windows = w->next;
 303                 free(w);
 304         }
 305 }
 306
 307 int close_pack_fd(struct packed_git *p)
 308 {
 309         if (p->pack_fd < 0)
 310                 return 0;
 311
 312         close(p->pack_fd);
 313         pack_open_fds--;
 314         p->pack_fd = -1;
 315
 316         return 1;
 317 }
 318
 319 void close_pack_index(struct packed_git *p)
 320 {
 321         if (p->index_data) {
 322                 munmap((void *)p->index_data, p->index_size);
 323                 p->index_data = NULL;
 324         }
 325 }
 326
 327 void close_pack(struct packed_git *p)
 328 {
 329         close_pack_windows(p);
 330         close_pack_fd(p);
 331         close_pack_index(p);
 332 }
 333
 334 void close_object_store(struct raw_object_store *o)
 335 {
 336         struct packed_git *p;
 337
 338         for (p = o->packed_git; p; p = p->next)
 339                 if (p->do_not_close)
 340                         BUG("want to close pack marked 'do-not-close'");
 341                 else
 342                         close_pack(p);
 343
 344         if (o->multi_pack_index) {
 345                 close_midx(o->multi_pack_index);
 346                 o->multi_pack_index = NULL;
 347         }
 348
 349         close_commit_graph(o);
 350 }
 351
 352 void unlink_pack_path(const char *pack_name, int force_delete)
 353 {
 354         static const char *exts[] = {".pack", ".idx", ".keep", ".bitmap", ".promisor"};
 355         int i;
 356         struct strbuf buf = STRBUF_INIT;
 357         size_t plen;
 358
 359         strbuf_addstr(&buf, pack_name);
 360         strip_suffix_mem(buf.buf, &buf.len, ".pack");
 361         plen = buf.len;
 362
 363         if (!force_delete) {
 364                 strbuf_addstr(&buf, ".keep");
 365                 if (!access(buf.buf, F_OK)) {
 366                         strbuf_release(&buf);
 367                         return;
 368                 }
 369         }
 370
 371         for (i = 0; i < ARRAY_SIZE(exts); i++) {
 372                 strbuf_setlen(&buf, plen);
 373                 strbuf_addstr(&buf, exts[i]);
 374                 unlink(buf.buf);
 375         }
 376
 377         strbuf_release(&buf);
 378 }
 379
 380 /*
 381  * The LRU pack is the one with the oldest MRU window, preferring packs
 382  * with no used windows, or the oldest mtime if it has no windows allocated.
 383  */
 384 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
 385 {
 386         struct pack_window *w, *this_mru_w;
 387         int has_windows_inuse = 0;
 388
 389         /*
 390          * Reject this pack if it has windows and the previously selected
 391          * one does not.  If this pack does not have windows, reject
 392          * it if the pack file is newer than the previously selected one.
 393          */
 394         if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
 395                 return;
 396
 397         for (w = this_mru_w = p->windows; w; w = w->next) {
 398                 /*
 399                  * Reject this pack if any of its windows are in use,
 400                  * but the previously selected pack did not have any
 401                  * inuse windows.  Otherwise, record that this pack
 402                  * has windows in use.
 403                  */
 404                 if (w->inuse_cnt) {
 405                         if (*accept_windows_inuse)
 406                                 has_windows_inuse = 1;
 407                         else
 408                                 return;
 409                 }
 410
 411                 if (w->last_used > this_mru_w->last_used)
 412                         this_mru_w = w;
 413
 414                 /*
 415                  * Reject this pack if it has windows that have been
 416                  * used more recently than the previously selected pack.
 417                  * If the previously selected pack had windows inuse and
 418                  * we have not encountered a window in this pack that is
 419                  * inuse, skip this check since we prefer a pack with no
 420                  * inuse windows to one that has inuse windows.
 421                  */
 422                 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
 423                     this_mru_w->last_used > (*mru_w)->last_used)
 424                         return;
 425         }
 426
 427         /*
 428          * Select this pack.
 429          */
 430         *mru_w = this_mru_w;
 431         *lru_p = p;
 432         *accept_windows_inuse = has_windows_inuse;
 433 }
 434
 435 static int close_one_pack(void)
 436 {
 437         struct packed_git *p, *lru_p = NULL;
 438         struct pack_window *mru_w = NULL;
 439         int accept_windows_inuse = 1;
 440
 441         for (p = the_repository->objects->packed_git; p; p = p->next) {
 442                 if (p->pack_fd == -1)
 443                         continue;
 444                 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
 445         }
 446
 447         if (lru_p)
 448                 return close_pack_fd(lru_p);
 449
 450         return 0;
 451 }
 452
 453 static unsigned int get_max_fd_limit(void)
 454 {
 455 #ifdef RLIMIT_NOFILE
 456         {
 457                 struct rlimit lim;
 458
 459                 if (!getrlimit(RLIMIT_NOFILE, &lim))
 460                         return lim.rlim_cur;
 461         }
 462 #endif
 463
 464 #ifdef _SC_OPEN_MAX
 465         {
 466                 long open_max = sysconf(_SC_OPEN_MAX);
 467                 if (0 < open_max)
 468                         return open_max;
 469                 /*
 470                  * Otherwise, we got -1 for one of the two
 471                  * reasons:
 472                  *
 473                  * (1) sysconf() did not understand _SC_OPEN_MAX
 474                  *     and signaled an error with -1; or
 475                  * (2) sysconf() said there is no limit.
 476                  *
 477                  * We _could_ clear errno before calling sysconf() to
 478                  * tell these two cases apart and return a huge number
 479                  * in the latter case to let the caller cap it to a
 480                  * value that is not so selfish, but letting the
 481                  * fallback OPEN_MAX codepath take care of these cases
 482                  * is a lot simpler.
 483                  */
 484         }
 485 #endif
 486
 487 #ifdef OPEN_MAX
 488         return OPEN_MAX;
 489 #else
 490         return 1; /* see the caller ;-) */
 491 #endif
 492 }
 493
 494 const char *pack_basename(struct packed_git *p)
 495 {
 496         const char *ret = strrchr(p->pack_name, '/');
 497         if (ret)
 498                 ret = ret + 1; /* skip past slash */
 499         else
 500                 ret = p->pack_name; /* we only have a base */
 501         return ret;
 502 }
 503
 504 /*
 505  * Do not call this directly as this leaks p->pack_fd on error return;
 506  * call open_packed_git() instead.
 507  */
 508 static int open_packed_git_1(struct packed_git *p)
 509 {
 510         struct stat st;
 511         struct pack_header hdr;
 512         unsigned char hash[GIT_MAX_RAWSZ];
 513         unsigned char *idx_hash;
 514         long fd_flag;
 515         ssize_t read_result;
 516         const unsigned hashsz = the_hash_algo->rawsz;
 517
 518         if (!p->index_data) {
 519                 struct multi_pack_index *m;
 520                 const char *pack_name = pack_basename(p);
 521
 522                 for (m = the_repository->objects->multi_pack_index;
 523                      m; m = m->next) {
 524                         if (midx_contains_pack(m, pack_name))
 525                                 break;
 526                 }
 527
 528                 if (!m && open_pack_index(p))
 529                         return error("packfile %s index unavailable", p->pack_name);
 530         }
 531
 532         if (!pack_max_fds) {
 533                 unsigned int max_fds = get_max_fd_limit();
 534
 535                 /* Save 3 for stdin/stdout/stderr, 22 for work */
 536                 if (25 < max_fds)
 537                         pack_max_fds = max_fds - 25;
 538                 else
 539                         pack_max_fds = 1;
 540         }
 541
 542         while (pack_max_fds <= pack_open_fds && close_one_pack())
 543                 ; /* nothing */
 544
 545         p->pack_fd = git_open(p->pack_name);
 546         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
 547                 return -1;
 548         pack_open_fds++;
 549
 550         /* If we created the struct before we had the pack we lack size. */
 551         if (!p->pack_size) {
 552                 if (!S_ISREG(st.st_mode))
 553                         return error("packfile %s not a regular file", p->pack_name);
 554                 p->pack_size = st.st_size;
 555         } else if (p->pack_size != st.st_size)
 556                 return error("packfile %s size changed", p->pack_name);
 557
 558         /* We leave these file descriptors open with sliding mmap;
 559          * there is no point keeping them open across exec(), though.
 560          */
 561         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
 562         if (fd_flag < 0)
 563                 return error("cannot determine file descriptor flags");
 564         fd_flag |= FD_CLOEXEC;
 565         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
 566                 return error("cannot set FD_CLOEXEC");
 567
 568         /* Verify we recognize this pack file format. */
 569         read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
 570         if (read_result < 0)
 571                 return error_errno("error reading from %s", p->pack_name);
 572         if (read_result != sizeof(hdr))
 573                 return error("file %s is far too short to be a packfile", p->pack_name);
 574         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
 575                 return error("file %s is not a GIT packfile", p->pack_name);
 576         if (!pack_version_ok(hdr.hdr_version))
 577                 return error("packfile %s is version %"PRIu32" and not"
 578                         " supported (try upgrading GIT to a newer version)",
 579                         p->pack_name, ntohl(hdr.hdr_version));
 580
 581         /* Skip index checking if in multi-pack-index */
 582         if (!p->index_data)
 583                 return 0;
 584
 585         /* Verify the pack matches its index. */
 586         if (p->num_objects != ntohl(hdr.hdr_entries))
 587                 return error("packfile %s claims to have %"PRIu32" objects"
 588                              " while index indicates %"PRIu32" objects",
 589                              p->pack_name, ntohl(hdr.hdr_entries),
 590                              p->num_objects);
 591         if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
 592                 return error("end of packfile %s is unavailable", p->pack_name);
 593         read_result = read_in_full(p->pack_fd, hash, hashsz);
 594         if (read_result < 0)
 595                 return error_errno("error reading from %s", p->pack_name);
 596         if (read_result != hashsz)
 597                 return error("packfile %s signature is unavailable", p->pack_name);
 598         idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
 599         if (!hasheq(hash, idx_hash))
 600                 return error("packfile %s does not match index", p->pack_name);
 601         return 0;
 602 }
 603
 604 static int open_packed_git(struct packed_git *p)
 605 {
 606         if (!open_packed_git_1(p))
 607                 return 0;
 608         close_pack_fd(p);
 609         return -1;
 610 }
 611
 612 static int in_window(struct pack_window *win, off_t offset)
 613 {
 614         /* We must promise at least one full hash after the
 615          * offset is available from this window, otherwise the offset
 616          * is not actually in this window and a different window (which
 617          * has that one hash excess) must be used.  This is to support
 618          * the object header and delta base parsing routines below.
 619          */
 620         off_t win_off = win->offset;
 621         return win_off <= offset
 622                 && (offset + the_hash_algo->rawsz) <= (win_off + win->len);
 623 }
 624
 625 unsigned char *use_pack(struct packed_git *p,
 626                 struct pack_window **w_cursor,
 627                 off_t offset,
 628                 unsigned long *left)
 629 {
 630         struct pack_window *win = *w_cursor;
 631
 632         /* Since packfiles end in a hash of their content and it's
 633          * pointless to ask for an offset into the middle of that
 634          * hash, and the in_window function above wouldn't match
 635          * don't allow an offset too close to the end of the file.
 636          */
 637         if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
 638                 die("packfile %s cannot be accessed", p->pack_name);
 639         if (offset > (p->pack_size - the_hash_algo->rawsz))
 640                 die("offset beyond end of packfile (truncated pack?)");
 641         if (offset < 0)
 642                 die(_("offset before end of packfile (broken .idx?)"));
 643
 644         if (!win || !in_window(win, offset)) {
 645                 if (win)
 646                         win->inuse_cnt--;
 647                 for (win = p->windows; win; win = win->next) {
 648                         if (in_window(win, offset))
 649                                 break;
 650                 }
 651                 if (!win) {
 652                         size_t window_align = packed_git_window_size / 2;
 653                         off_t len;
 654
 655                         if (p->pack_fd == -1 && open_packed_git(p))
 656                                 die("packfile %s cannot be accessed", p->pack_name);
 657
 658                         win = xcalloc(1, sizeof(*win));
 659                         win->offset = (offset / window_align) * window_align;
 660                         len = p->pack_size - win->offset;
 661                         if (len > packed_git_window_size)
 662                                 len = packed_git_window_size;
 663                         win->len = (size_t)len;
 664                         pack_mapped += win->len;
 665                         while (packed_git_limit < pack_mapped
 666                                 && unuse_one_window(p))
 667                                 ; /* nothing */
 668                         win->base = xmmap_gently(NULL, win->len,
 669                                 PROT_READ, MAP_PRIVATE,
 670                                 p->pack_fd, win->offset);
 671                         if (win->base == MAP_FAILED)
 672                                 die_errno("packfile %s cannot be mapped",
 673                                           p->pack_name);
 674                         if (!win->offset && win->len == p->pack_size
 675                                 && !p->do_not_close)
 676                                 close_pack_fd(p);
 677                         pack_mmap_calls++;
 678                         pack_open_windows++;
 679                         if (pack_mapped > peak_pack_mapped)
 680                                 peak_pack_mapped = pack_mapped;
 681                         if (pack_open_windows > peak_pack_open_windows)
 682                                 peak_pack_open_windows = pack_open_windows;
 683                         win->next = p->windows;
 684                         p->windows = win;
 685                 }
 686         }
 687         if (win != *w_cursor) {
 688                 win->last_used = pack_used_ctr++;
 689                 win->inuse_cnt++;
 690                 *w_cursor = win;
 691         }
 692         offset -= win->offset;
 693         if (left)
 694                 *left = win->len - xsize_t(offset);
 695         return win->base + offset;
 696 }
 697
 698 void unuse_pack(struct pack_window **w_cursor)
 699 {
 700         struct pack_window *w = *w_cursor;
 701         if (w) {
 702                 w->inuse_cnt--;
 703                 *w_cursor = NULL;
 704         }
 705 }
 706
 707 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
 708 {
 709         struct stat st;
 710         size_t alloc;
 711         struct packed_git *p;
 712
 713         /*
 714          * Make sure a corresponding .pack file exists and that
 715          * the index looks sane.
 716          */
 717         if (!strip_suffix_mem(path, &path_len, ".idx"))
 718                 return NULL;
 719
 720         /*
 721          * ".promisor" is long enough to hold any suffix we're adding (and
 722          * the use xsnprintf double-checks that)
 723          */
 724         alloc = st_add3(path_len, strlen(".promisor"), 1);
 725         p = alloc_packed_git(alloc);
 726         memcpy(p->pack_name, path, path_len);
 727
 728         xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
 729         if (!access(p->pack_name, F_OK))
 730                 p->pack_keep = 1;
 731
 732         xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
 733         if (!access(p->pack_name, F_OK))
 734                 p->pack_promisor = 1;
 735
 736         xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
 737         if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
 738                 free(p);
 739                 return NULL;
 740         }
 741
 742         /* ok, it looks sane as far as we can check without
 743          * actually mapping the pack file.
 744          */
 745         p->pack_size = st.st_size;
 746         p->pack_local = local;
 747         p->mtime = st.st_mtime;
 748         if (path_len < the_hash_algo->hexsz ||
 749             get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->hash))
 750                 hashclr(p->hash);
 751         return p;
 752 }
 753
 754 void install_packed_git(struct repository *r, struct packed_git *pack)
 755 {
 756         if (pack->pack_fd != -1)
 757                 pack_open_fds++;
 758
 759         pack->next = r->objects->packed_git;
 760         r->objects->packed_git = pack;
 761 }
 762
 763 void (*report_garbage)(unsigned seen_bits, const char *path);
 764
 765 static void report_helper(const struct string_list *list,
 766                           int seen_bits, int first, int last)
 767 {
 768         if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
 769                 return;
 770
 771         for (; first < last; first++)
 772                 report_garbage(seen_bits, list->items[first].string);
 773 }
 774
 775 static void report_pack_garbage(struct string_list *list)
 776 {
 777         int i, baselen = -1, first = 0, seen_bits = 0;
 778
 779         if (!report_garbage)
 780                 return;
 781
 782         string_list_sort(list);
 783
 784         for (i = 0; i < list->nr; i++) {
 785                 const char *path = list->items[i].string;
 786                 if (baselen != -1 &&
 787                     strncmp(path, list->items[first].string, baselen)) {
 788                         report_helper(list, seen_bits, first, i);
 789                         baselen = -1;
 790                         seen_bits = 0;
 791                 }
 792                 if (baselen == -1) {
 793                         const char *dot = strrchr(path, '.');
 794                         if (!dot) {
 795                                 report_garbage(PACKDIR_FILE_GARBAGE, path);
 796                                 continue;
 797                         }
 798                         baselen = dot - path + 1;
 799                         first = i;
 800                 }
 801                 if (!strcmp(path + baselen, "pack"))
 802                         seen_bits |= 1;
 803                 else if (!strcmp(path + baselen, "idx"))
 804                         seen_bits |= 2;
 805         }
 806         report_helper(list, seen_bits, first, list->nr);
 807 }
 808
 809 void for_each_file_in_pack_dir(const char *objdir,
 810                                each_file_in_pack_dir_fn fn,
 811                                void *data)
 812 {
 813         struct strbuf path = STRBUF_INIT;
 814         size_t dirnamelen;
 815         DIR *dir;
 816         struct dirent *de;
 817
 818         strbuf_addstr(&path, objdir);
 819         strbuf_addstr(&path, "/pack");
 820         dir = opendir(path.buf);
 821         if (!dir) {
 822                 if (errno != ENOENT)
 823                         error_errno("unable to open object pack directory: %s",
 824                                     path.buf);
 825                 strbuf_release(&path);
 826                 return;
 827         }
 828         strbuf_addch(&path, '/');
 829         dirnamelen = path.len;
 830         while ((de = readdir(dir)) != NULL) {
 831                 if (is_dot_or_dotdot(de->d_name))
 832                         continue;
 833
 834                 strbuf_setlen(&path, dirnamelen);
 835                 strbuf_addstr(&path, de->d_name);
 836
 837                 fn(path.buf, path.len, de->d_name, data);
 838         }
 839
 840         closedir(dir);
 841         strbuf_release(&path);
 842 }
 843
 844 struct prepare_pack_data {
 845         struct repository *r;
 846         struct string_list *garbage;
 847         int local;
 848         struct multi_pack_index *m;
 849 };
 850
 851 static void prepare_pack(const char *full_name, size_t full_name_len,
 852                          const char *file_name, void *_data)
 853 {
 854         struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
 855         struct packed_git *p;
 856         size_t base_len = full_name_len;
 857
 858         if (strip_suffix_mem(full_name, &base_len, ".idx") &&
 859             !(data->m && midx_contains_pack(data->m, file_name))) {
 860                 /* Don't reopen a pack we already have. */
 861                 for (p = data->r->objects->packed_git; p; p = p->next) {
 862                         size_t len;
 863                         if (strip_suffix(p->pack_name, ".pack", &len) &&
 864                             len == base_len &&
 865                             !memcmp(p->pack_name, full_name, len))
 866                                 break;
 867                 }
 868
 869                 if (!p) {
 870                         p = add_packed_git(full_name, full_name_len, data->local);
 871                         if (p)
 872                                 install_packed_git(data->r, p);
 873                 }
 874         }
 875
 876         if (!report_garbage)
 877                 return;
 878
 879         if (!strcmp(file_name, "multi-pack-index"))
 880                 return;
 881         if (ends_with(file_name, ".idx") ||
 882             ends_with(file_name, ".pack") ||
 883             ends_with(file_name, ".bitmap") ||
 884             ends_with(file_name, ".keep") ||
 885             ends_with(file_name, ".promisor"))
 886                 string_list_append(data->garbage, full_name);
 887         else
 888                 report_garbage(PACKDIR_FILE_GARBAGE, full_name);
 889 }
 890
 891 static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
 892 {
 893         struct prepare_pack_data data;
 894         struct string_list garbage = STRING_LIST_INIT_DUP;
 895
 896         data.m = r->objects->multi_pack_index;
 897
 898         /* look for the multi-pack-index for this object directory */
 899         while (data.m && strcmp(data.m->object_dir, objdir))
 900                 data.m = data.m->next;
 901
 902         data.r = r;
 903         data.garbage = &garbage;
 904         data.local = local;
 905
 906         for_each_file_in_pack_dir(objdir, prepare_pack, &data);
 907
 908         report_pack_garbage(data.garbage);
 909         string_list_clear(data.garbage, 0);
 910 }
 911
 912 static void prepare_packed_git(struct repository *r);
 913 /*
 914  * Give a fast, rough count of the number of objects in the repository. This
 915  * ignores loose objects completely. If you have a lot of them, then either
 916  * you should repack because your performance will be awful, or they are
 917  * all unreachable objects about to be pruned, in which case they're not really
 918  * interesting as a measure of repo size in the first place.
 919  */
 920 unsigned long repo_approximate_object_count(struct repository *r)
 921 {
 922         if (!r->objects->approximate_object_count_valid) {
 923                 unsigned long count;
 924                 struct multi_pack_index *m;
 925                 struct packed_git *p;
 926
 927                 prepare_packed_git(r);
 928                 count = 0;
 929                 for (m = get_multi_pack_index(r); m; m = m->next)
 930                         count += m->num_objects;
 931                 for (p = r->objects->packed_git; p; p = p->next) {
 932                         if (open_pack_index(p))
 933                                 continue;
 934                         count += p->num_objects;
 935                 }
 936                 r->objects->approximate_object_count = count;
 937         }
 938         return r->objects->approximate_object_count;
 939 }
 940
 941 static void *get_next_packed_git(const void *p)
 942 {
 943         return ((const struct packed_git *)p)->next;
 944 }
 945
 946 static void set_next_packed_git(void *p, void *next)
 947 {
 948         ((struct packed_git *)p)->next = next;
 949 }
 950
 951 static int sort_pack(const void *a_, const void *b_)
 952 {
 953         const struct packed_git *a = a_;
 954         const struct packed_git *b = b_;
 955         int st;
 956
 957         /*
 958          * Local packs tend to contain objects specific to our
 959          * variant of the project than remote ones.  In addition,
 960          * remote ones could be on a network mounted filesystem.
 961          * Favor local ones for these reasons.
 962          */
 963         st = a->pack_local - b->pack_local;
 964         if (st)
 965                 return -st;
 966
 967         /*
 968          * Younger packs tend to contain more recent objects,
 969          * and more recent objects tend to get accessed more
 970          * often.
 971          */
 972         if (a->mtime < b->mtime)
 973                 return 1;
 974         else if (a->mtime == b->mtime)
 975                 return 0;
 976         return -1;
 977 }
 978
 979 static void rearrange_packed_git(struct repository *r)
 980 {
 981         r->objects->packed_git = llist_mergesort(
 982                 r->objects->packed_git, get_next_packed_git,
 983                 set_next_packed_git, sort_pack);
 984 }
 985
 986 static void prepare_packed_git_mru(struct repository *r)
 987 {
 988         struct packed_git *p;
 989
 990         INIT_LIST_HEAD(&r->objects->packed_git_mru);
 991
 992         for (p = r->objects->packed_git; p; p = p->next)
 993                 list_add_tail(&p->mru, &r->objects->packed_git_mru);
 994 }
 995
 996 static void prepare_packed_git(struct repository *r)
 997 {
 998         struct object_directory *odb;
 999
1000         if (r->objects->packed_git_initialized)
1001                 return;
1002
1003         prepare_alt_odb(r);
1004         for (odb = r->objects->odb; odb; odb = odb->next) {
1005                 int local = (odb == r->objects->odb);
1006                 prepare_multi_pack_index_one(r, odb->path, local);
1007                 prepare_packed_git_one(r, odb->path, local);
1008         }
1009         rearrange_packed_git(r);
1010
1011         prepare_packed_git_mru(r);
1012         r->objects->packed_git_initialized = 1;
1013 }
1014
1015 void reprepare_packed_git(struct repository *r)
1016 {
1017         struct object_directory *odb;
1018
1019         for (odb = r->objects->odb; odb; odb = odb->next)
1020                 odb_clear_loose_cache(odb);
1021
1022         r->objects->approximate_object_count_valid = 0;
1023         r->objects->packed_git_initialized = 0;
1024         prepare_packed_git(r);
1025 }
1026
1027 struct packed_git *get_packed_git(struct repository *r)
1028 {
1029         prepare_packed_git(r);
1030         return r->objects->packed_git;
1031 }
1032
1033 struct multi_pack_index *get_multi_pack_index(struct repository *r)
1034 {
1035         prepare_packed_git(r);
1036         return r->objects->multi_pack_index;
1037 }
1038
1039 struct packed_git *get_all_packs(struct repository *r)
1040 {
1041         struct multi_pack_index *m;
1042
1043         prepare_packed_git(r);
1044         for (m = r->objects->multi_pack_index; m; m = m->next) {
1045                 uint32_t i;
1046                 for (i = 0; i < m->num_packs; i++)
1047                         prepare_midx_pack(r, m, i);
1048         }
1049
1050         return r->objects->packed_git;
1051 }
1052
1053 struct list_head *get_packed_git_mru(struct repository *r)
1054 {
1055         prepare_packed_git(r);
1056         return &r->objects->packed_git_mru;
1057 }
1058
1059 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1060                 unsigned long len, enum object_type *type, unsigned long *sizep)
1061 {
1062         unsigned shift;
1063         unsigned long size, c;
1064         unsigned long used = 0;
1065
1066         c = buf[used++];
1067         *type = (c >> 4) & 7;
1068         size = c & 15;
1069         shift = 4;
1070         while (c & 0x80) {
1071                 if (len <= used || bitsizeof(long) <= shift) {
1072                         error("bad object header");
1073                         size = used = 0;
1074                         break;
1075                 }
1076                 c = buf[used++];
1077                 size += (c & 0x7f) << shift;
1078                 shift += 7;
1079         }
1080         *sizep = size;
1081         return used;
1082 }
1083
1084 unsigned long get_size_from_delta(struct packed_git *p,
1085                                   struct pack_window **w_curs,
1086                                   off_t curpos)
1087 {
1088         const unsigned char *data;
1089         unsigned char delta_head[20], *in;
1090         git_zstream stream;
1091         int st;
1092
1093         memset(&stream, 0, sizeof(stream));
1094         stream.next_out = delta_head;
1095         stream.avail_out = sizeof(delta_head);
1096
1097         git_inflate_init(&stream);
1098         do {
1099                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1100                 stream.next_in = in;
1101                 st = git_inflate(&stream, Z_FINISH);
1102                 curpos += stream.next_in - in;
1103         } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1104                  stream.total_out < sizeof(delta_head));
1105         git_inflate_end(&stream);
1106         if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1107                 error("delta data unpack-initial failed");
1108                 return 0;
1109         }
1110
1111         /* Examine the initial part of the delta to figure out
1112          * the result size.
1113          */
1114         data = delta_head;
1115
1116         /* ignore base size */
1117         get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1118
1119         /* Read the result size */
1120         return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1121 }
1122
1123 int unpack_object_header(struct packed_git *p,
1124                          struct pack_window **w_curs,
1125                          off_t *curpos,
1126                          unsigned long *sizep)
1127 {
1128         unsigned char *base;
1129         unsigned long left;
1130         unsigned long used;
1131         enum object_type type;
1132
1133         /* use_pack() assures us we have [base, base + 20) available
1134          * as a range that we can look at.  (Its actually the hash
1135          * size that is assured.)  With our object header encoding
1136          * the maximum deflated object size is 2^137, which is just
1137          * insane, so we know won't exceed what we have been given.
1138          */
1139         base = use_pack(p, w_curs, *curpos, &left);
1140         used = unpack_object_header_buffer(base, left, &type, sizep);
1141         if (!used) {
1142                 type = OBJ_BAD;
1143         } else
1144                 *curpos += used;
1145
1146         return type;
1147 }
1148
1149 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1150 {
1151         unsigned i;
1152         const unsigned hashsz = the_hash_algo->rawsz;
1153         for (i = 0; i < p->num_bad_objects; i++)
1154                 if (hasheq(sha1, p->bad_object_sha1 + hashsz * i))
1155                         return;
1156         p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1157                                       st_mult(GIT_MAX_RAWSZ,
1158                                               st_add(p->num_bad_objects, 1)));
1159         hashcpy(p->bad_object_sha1 + hashsz * p->num_bad_objects, sha1);
1160         p->num_bad_objects++;
1161 }
1162
1163 const struct packed_git *has_packed_and_bad(struct repository *r,
1164                                             const unsigned char *sha1)
1165 {
1166         struct packed_git *p;
1167         unsigned i;
1168
1169         for (p = r->objects->packed_git; p; p = p->next)
1170                 for (i = 0; i < p->num_bad_objects; i++)
1171                         if (hasheq(sha1,
1172                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1173                                 return p;
1174         return NULL;
1175 }
1176
1177 static off_t get_delta_base(struct packed_git *p,
1178                                     struct pack_window **w_curs,
1179                                     off_t *curpos,
1180                                     enum object_type type,
1181                                     off_t delta_obj_offset)
1182 {
1183         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1184         off_t base_offset;
1185
1186         /* use_pack() assured us we have [base_info, base_info + 20)
1187          * as a range that we can look at without walking off the
1188          * end of the mapped window.  Its actually the hash size
1189          * that is assured.  An OFS_DELTA longer than the hash size
1190          * is stupid, as then a REF_DELTA would be smaller to store.
1191          */
1192         if (type == OBJ_OFS_DELTA) {
1193                 unsigned used = 0;
1194                 unsigned char c = base_info[used++];
1195                 base_offset = c & 127;
1196                 while (c & 128) {
1197                         base_offset += 1;
1198                         if (!base_offset || MSB(base_offset, 7))
1199                                 return 0;  /* overflow */
1200                         c = base_info[used++];
1201                         base_offset = (base_offset << 7) + (c & 127);
1202                 }
1203                 base_offset = delta_obj_offset - base_offset;
1204                 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1205                         return 0;  /* out of bound */
1206                 *curpos += used;
1207         } else if (type == OBJ_REF_DELTA) {
1208                 /* The base entry _must_ be in the same pack */
1209                 base_offset = find_pack_entry_one(base_info, p);
1210                 *curpos += the_hash_algo->rawsz;
1211         } else
1212                 die("I am totally screwed");
1213         return base_offset;
1214 }
1215
1216 /*
1217  * Like get_delta_base above, but we return the sha1 instead of the pack
1218  * offset. This means it is cheaper for REF deltas (we do not have to do
1219  * the final object lookup), but more expensive for OFS deltas (we
1220  * have to load the revidx to convert the offset back into a sha1).
1221  */
1222 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1223                                                 struct pack_window **w_curs,
1224                                                 off_t curpos,
1225                                                 enum object_type type,
1226                                                 off_t delta_obj_offset)
1227 {
1228         if (type == OBJ_REF_DELTA) {
1229                 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1230                 return base;
1231         } else if (type == OBJ_OFS_DELTA) {
1232                 struct revindex_entry *revidx;
1233                 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1234                                                    type, delta_obj_offset);
1235
1236                 if (!base_offset)
1237                         return NULL;
1238
1239                 revidx = find_pack_revindex(p, base_offset);
1240                 if (!revidx)
1241                         return NULL;
1242
1243                 return nth_packed_object_sha1(p, revidx->nr);
1244         } else
1245                 return NULL;
1246 }
1247
1248 static int retry_bad_packed_offset(struct repository *r,
1249                                    struct packed_git *p,
1250                                    off_t obj_offset)
1251 {
1252         int type;
1253         struct revindex_entry *revidx;
1254         struct object_id oid;
1255         revidx = find_pack_revindex(p, obj_offset);
1256         if (!revidx)
1257                 return OBJ_BAD;
1258         nth_packed_object_oid(&oid, p, revidx->nr);
1259         mark_bad_packed_object(p, oid.hash);
1260         type = oid_object_info(r, &oid, NULL);
1261         if (type <= OBJ_NONE)
1262                 return OBJ_BAD;
1263         return type;
1264 }
1265
1266 #define POI_STACK_PREALLOC 64
1267
1268 static enum object_type packed_to_object_type(struct repository *r,
1269                                               struct packed_git *p,
1270                                               off_t obj_offset,
1271                                               enum object_type type,
1272                                               struct pack_window **w_curs,
1273                                               off_t curpos)
1274 {
1275         off_t small_poi_stack[POI_STACK_PREALLOC];
1276         off_t *poi_stack = small_poi_stack;
1277         int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1278
1279         while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1280                 off_t base_offset;
1281                 unsigned long size;
1282                 /* Push the object we're going to leave behind */
1283                 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1284                         poi_stack_alloc = alloc_nr(poi_stack_nr);
1285                         ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1286                         COPY_ARRAY(poi_stack, small_poi_stack, poi_stack_nr);
1287                 } else {
1288                         ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1289                 }
1290                 poi_stack[poi_stack_nr++] = obj_offset;
1291                 /* If parsing the base offset fails, just unwind */
1292                 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1293                 if (!base_offset)
1294                         goto unwind;
1295                 curpos = obj_offset = base_offset;
1296                 type = unpack_object_header(p, w_curs, &curpos, &size);
1297                 if (type <= OBJ_NONE) {
1298                         /* If getting the base itself fails, we first
1299                          * retry the base, otherwise unwind */
1300                         type = retry_bad_packed_offset(r, p, base_offset);
1301                         if (type > OBJ_NONE)
1302                                 goto out;
1303                         goto unwind;
1304                 }
1305         }
1306
1307         switch (type) {
1308         case OBJ_BAD:
1309         case OBJ_COMMIT:
1310         case OBJ_TREE:
1311         case OBJ_BLOB:
1312         case OBJ_TAG:
1313                 break;
1314         default:
1315                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1316                       type, (uintmax_t)obj_offset, p->pack_name);
1317                 type = OBJ_BAD;
1318         }
1319
1320 out:
1321         if (poi_stack != small_poi_stack)
1322                 free(poi_stack);
1323         return type;
1324
1325 unwind:
1326         while (poi_stack_nr) {
1327                 obj_offset = poi_stack[--poi_stack_nr];
1328                 type = retry_bad_packed_offset(r, p, obj_offset);
1329                 if (type > OBJ_NONE)
1330                         goto out;
1331         }
1332         type = OBJ_BAD;
1333         goto out;
1334 }
1335
1336 static struct hashmap delta_base_cache;
1337 static size_t delta_base_cached;
1338
1339 static LIST_HEAD(delta_base_cache_lru);
1340
1341 struct delta_base_cache_key {
1342         struct packed_git *p;
1343         off_t base_offset;
1344 };
1345
1346 struct delta_base_cache_entry {
1347         struct hashmap hash;
1348         struct delta_base_cache_key key;
1349         struct list_head lru;
1350         void *data;
1351         unsigned long size;
1352         enum object_type type;
1353 };
1354
1355 static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1356 {
1357         unsigned int hash;
1358
1359         hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1360         hash += (hash >> 8) + (hash >> 16);
1361         return hash;
1362 }
1363
1364 static struct delta_base_cache_entry *
1365 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1366 {
1367         struct hashmap_entry entry;
1368         struct delta_base_cache_key key;
1369
1370         if (!delta_base_cache.cmpfn)
1371                 return NULL;
1372
1373         hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1374         key.p = p;
1375         key.base_offset = base_offset;
1376         return hashmap_get(&delta_base_cache, &entry, &key);
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 void *va, const void *vb,
1387                                      const void *vkey)
1388 {
1389         const struct delta_base_cache_entry *a = va, *b = vb;
1390         const struct delta_base_cache_key *key = vkey;
1391         if (key)
1392                 return !delta_base_cache_key_eq(&a->key, key);
1393         else
1394                 return !delta_base_cache_key_eq(&a->key, &b->key);
1395 }
1396
1397 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1398 {
1399         return !!get_delta_base_cache_entry(p, base_offset);
1400 }
1401
1402 /*
1403  * Remove the entry from the cache, but do _not_ free the associated
1404  * entry data. The caller takes ownership of the "data" buffer, and
1405  * should copy out any fields it wants before detaching.
1406  */
1407 static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1408 {
1409         hashmap_remove(&delta_base_cache, ent, &ent->key);
1410         list_del(&ent->lru);
1411         delta_base_cached -= ent->size;
1412         free(ent);
1413 }
1414
1415 static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
1416                                    off_t base_offset, unsigned long *base_size,
1417                                    enum object_type *type)
1418 {
1419         struct delta_base_cache_entry *ent;
1420
1421         ent = get_delta_base_cache_entry(p, base_offset);
1422         if (!ent)
1423                 return unpack_entry(r, p, base_offset, type, base_size);
1424
1425         if (type)
1426                 *type = ent->type;
1427         if (base_size)
1428                 *base_size = ent->size;
1429         return xmemdupz(ent->data, ent->size);
1430 }
1431
1432 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1433 {
1434         free(ent->data);
1435         detach_delta_base_cache_entry(ent);
1436 }
1437
1438 void clear_delta_base_cache(void)
1439 {
1440         struct list_head *lru, *tmp;
1441         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1442                 struct delta_base_cache_entry *entry =
1443                         list_entry(lru, struct delta_base_cache_entry, lru);
1444                 release_delta_base_cache(entry);
1445         }
1446 }
1447
1448 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1449         void *base, unsigned long base_size, enum object_type type)
1450 {
1451         struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1452         struct list_head *lru, *tmp;
1453
1454         delta_base_cached += base_size;
1455
1456         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1457                 struct delta_base_cache_entry *f =
1458                         list_entry(lru, struct delta_base_cache_entry, lru);
1459                 if (delta_base_cached <= delta_base_cache_limit)
1460                         break;
1461                 release_delta_base_cache(f);
1462         }
1463
1464         ent->key.p = p;
1465         ent->key.base_offset = base_offset;
1466         ent->type = type;
1467         ent->data = base;
1468         ent->size = base_size;
1469         list_add_tail(&ent->lru, &delta_base_cache_lru);
1470
1471         if (!delta_base_cache.cmpfn)
1472                 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1473         hashmap_entry_init(ent, pack_entry_hash(p, base_offset));
1474         hashmap_add(&delta_base_cache, ent);
1475 }
1476
1477 int packed_object_info(struct repository *r, struct packed_git *p,
1478                        off_t obj_offset, struct object_info *oi)
1479 {
1480         struct pack_window *w_curs = NULL;
1481         unsigned long size;
1482         off_t curpos = obj_offset;
1483         enum object_type type;
1484
1485         /*
1486          * We always get the representation type, but only convert it to
1487          * a "real" type later if the caller is interested.
1488          */
1489         if (oi->contentp) {
1490                 *oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
1491                                                       &type);
1492                 if (!*oi->contentp)
1493                         type = OBJ_BAD;
1494         } else {
1495                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1496         }
1497
1498         if (!oi->contentp && oi->sizep) {
1499                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1500                         off_t tmp_pos = curpos;
1501                         off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1502                                                            type, obj_offset);
1503                         if (!base_offset) {
1504                                 type = OBJ_BAD;
1505                                 goto out;
1506                         }
1507                         *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1508                         if (*oi->sizep == 0) {
1509                                 type = OBJ_BAD;
1510                                 goto out;
1511                         }
1512                 } else {
1513                         *oi->sizep = size;
1514                 }
1515         }
1516
1517         if (oi->disk_sizep) {
1518                 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1519                 *oi->disk_sizep = revidx[1].offset - obj_offset;
1520         }
1521
1522         if (oi->typep || oi->type_name) {
1523                 enum object_type ptot;
1524                 ptot = packed_to_object_type(r, p, obj_offset,
1525                                              type, &w_curs, curpos);
1526                 if (oi->typep)
1527                         *oi->typep = ptot;
1528                 if (oi->type_name) {
1529                         const char *tn = type_name(ptot);
1530                         if (tn)
1531                                 strbuf_addstr(oi->type_name, tn);
1532                 }
1533                 if (ptot < 0) {
1534                         type = OBJ_BAD;
1535                         goto out;
1536                 }
1537         }
1538
1539         if (oi->delta_base_sha1) {
1540                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1541                         const unsigned char *base;
1542
1543                         base = get_delta_base_sha1(p, &w_curs, curpos,
1544                                                    type, obj_offset);
1545                         if (!base) {
1546                                 type = OBJ_BAD;
1547                                 goto out;
1548                         }
1549
1550                         hashcpy(oi->delta_base_sha1, base);
1551                 } else
1552                         hashclr(oi->delta_base_sha1);
1553         }
1554
1555         oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1556                                                           OI_PACKED;
1557
1558 out:
1559         unuse_pack(&w_curs);
1560         return type;
1561 }
1562
1563 static void *unpack_compressed_entry(struct packed_git *p,
1564                                     struct pack_window **w_curs,
1565                                     off_t curpos,
1566                                     unsigned long size)
1567 {
1568         int st;
1569         git_zstream stream;
1570         unsigned char *buffer, *in;
1571
1572         buffer = xmallocz_gently(size);
1573         if (!buffer)
1574                 return NULL;
1575         memset(&stream, 0, sizeof(stream));
1576         stream.next_out = buffer;
1577         stream.avail_out = size + 1;
1578
1579         git_inflate_init(&stream);
1580         do {
1581                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1582                 stream.next_in = in;
1583                 st = git_inflate(&stream, Z_FINISH);
1584                 if (!stream.avail_out)
1585                         break; /* the payload is larger than it should be */
1586                 curpos += stream.next_in - in;
1587         } while (st == Z_OK || st == Z_BUF_ERROR);
1588         git_inflate_end(&stream);
1589         if ((st != Z_STREAM_END) || stream.total_out != size) {
1590                 free(buffer);
1591                 return NULL;
1592         }
1593
1594         /* versions of zlib can clobber unconsumed portion of outbuf */
1595         buffer[size] = '\0';
1596
1597         return buffer;
1598 }
1599
1600 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1601 {
1602         static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1603         trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1604                          p->pack_name, (uintmax_t)obj_offset);
1605 }
1606
1607 int do_check_packed_object_crc;
1608
1609 #define UNPACK_ENTRY_STACK_PREALLOC 64
1610 struct unpack_entry_stack_ent {
1611         off_t obj_offset;
1612         off_t curpos;
1613         unsigned long size;
1614 };
1615
1616 static void *read_object(struct repository *r,
1617                          const struct object_id *oid,
1618                          enum object_type *type,
1619                          unsigned long *size)
1620 {
1621         struct object_info oi = OBJECT_INFO_INIT;
1622         void *content;
1623         oi.typep = type;
1624         oi.sizep = size;
1625         oi.contentp = &content;
1626
1627         if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1628                 return NULL;
1629         return content;
1630 }
1631
1632 void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
1633                    enum object_type *final_type, unsigned long *final_size)
1634 {
1635         struct pack_window *w_curs = NULL;
1636         off_t curpos = obj_offset;
1637         void *data = NULL;
1638         unsigned long size;
1639         enum object_type type;
1640         struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1641         struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1642         int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1643         int base_from_cache = 0;
1644
1645         write_pack_access_log(p, obj_offset);
1646
1647         /* PHASE 1: drill down to the innermost base object */
1648         for (;;) {
1649                 off_t base_offset;
1650                 int i;
1651                 struct delta_base_cache_entry *ent;
1652
1653                 ent = get_delta_base_cache_entry(p, curpos);
1654                 if (ent) {
1655                         type = ent->type;
1656                         data = ent->data;
1657                         size = ent->size;
1658                         detach_delta_base_cache_entry(ent);
1659                         base_from_cache = 1;
1660                         break;
1661                 }
1662
1663                 if (do_check_packed_object_crc && p->index_version > 1) {
1664                         struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1665                         off_t len = revidx[1].offset - obj_offset;
1666                         if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1667                                 struct object_id oid;
1668                                 nth_packed_object_oid(&oid, p, revidx->nr);
1669                                 error("bad packed object CRC for %s",
1670                                       oid_to_hex(&oid));
1671                                 mark_bad_packed_object(p, oid.hash);
1672                                 data = NULL;
1673                                 goto out;
1674                         }
1675                 }
1676
1677                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1678                 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1679                         break;
1680
1681                 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1682                 if (!base_offset) {
1683                         error("failed to validate delta base reference "
1684                               "at offset %"PRIuMAX" from %s",
1685                               (uintmax_t)curpos, p->pack_name);
1686                         /* bail to phase 2, in hopes of recovery */
1687                         data = NULL;
1688                         break;
1689                 }
1690
1691                 /* push object, proceed to base */
1692                 if (delta_stack_nr >= delta_stack_alloc
1693                     && delta_stack == small_delta_stack) {
1694                         delta_stack_alloc = alloc_nr(delta_stack_nr);
1695                         ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1696                         COPY_ARRAY(delta_stack, small_delta_stack,
1697                                    delta_stack_nr);
1698                 } else {
1699                         ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1700                 }
1701                 i = delta_stack_nr++;
1702                 delta_stack[i].obj_offset = obj_offset;
1703                 delta_stack[i].curpos = curpos;
1704                 delta_stack[i].size = size;
1705
1706                 curpos = obj_offset = base_offset;
1707         }
1708
1709         /* PHASE 2: handle the base */
1710         switch (type) {
1711         case OBJ_OFS_DELTA:
1712         case OBJ_REF_DELTA:
1713                 if (data)
1714                         BUG("unpack_entry: left loop at a valid delta");
1715                 break;
1716         case OBJ_COMMIT:
1717         case OBJ_TREE:
1718         case OBJ_BLOB:
1719         case OBJ_TAG:
1720                 if (!base_from_cache)
1721                         data = unpack_compressed_entry(p, &w_curs, curpos, size);
1722                 break;
1723         default:
1724                 data = NULL;
1725                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1726                       type, (uintmax_t)obj_offset, p->pack_name);
1727         }
1728
1729         /* PHASE 3: apply deltas in order */
1730
1731         /* invariants:
1732          *   'data' holds the base data, or NULL if there was corruption
1733          */
1734         while (delta_stack_nr) {
1735                 void *delta_data;
1736                 void *base = data;
1737                 void *external_base = NULL;
1738                 unsigned long delta_size, base_size = size;
1739                 int i;
1740
1741                 data = NULL;
1742
1743                 if (base)
1744                         add_delta_base_cache(p, obj_offset, base, base_size, type);
1745
1746                 if (!base) {
1747                         /*
1748                          * We're probably in deep shit, but let's try to fetch
1749                          * the required base anyway from another pack or loose.
1750                          * This is costly but should happen only in the presence
1751                          * of a corrupted pack, and is better than failing outright.
1752                          */
1753                         struct revindex_entry *revidx;
1754                         struct object_id base_oid;
1755                         revidx = find_pack_revindex(p, obj_offset);
1756                         if (revidx) {
1757                                 nth_packed_object_oid(&base_oid, p, revidx->nr);
1758                                 error("failed to read delta base object %s"
1759                                       " at offset %"PRIuMAX" from %s",
1760                                       oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1761                                       p->pack_name);
1762                                 mark_bad_packed_object(p, base_oid.hash);
1763                                 base = read_object(r, &base_oid, &type, &base_size);
1764                                 external_base = base;
1765                         }
1766                 }
1767
1768                 i = --delta_stack_nr;
1769                 obj_offset = delta_stack[i].obj_offset;
1770                 curpos = delta_stack[i].curpos;
1771                 delta_size = delta_stack[i].size;
1772
1773                 if (!base)
1774                         continue;
1775
1776                 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1777
1778                 if (!delta_data) {
1779                         error("failed to unpack compressed delta "
1780                               "at offset %"PRIuMAX" from %s",
1781                               (uintmax_t)curpos, p->pack_name);
1782                         data = NULL;
1783                         free(external_base);
1784                         continue;
1785                 }
1786
1787                 data = patch_delta(base, base_size,
1788                                    delta_data, delta_size,
1789                                    &size);
1790
1791                 /*
1792                  * We could not apply the delta; warn the user, but keep going.
1793                  * Our failure will be noticed either in the next iteration of
1794                  * the loop, or if this is the final delta, in the caller when
1795                  * we return NULL. Those code paths will take care of making
1796                  * a more explicit warning and retrying with another copy of
1797                  * the object.
1798                  */
1799                 if (!data)
1800                         error("failed to apply delta");
1801
1802                 free(delta_data);
1803                 free(external_base);
1804         }
1805
1806         if (final_type)
1807                 *final_type = type;
1808         if (final_size)
1809                 *final_size = size;
1810
1811 out:
1812         unuse_pack(&w_curs);
1813
1814         if (delta_stack != small_delta_stack)
1815                 free(delta_stack);
1816
1817         return data;
1818 }
1819
1820 int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1821 {
1822         const unsigned char *index_fanout = p->index_data;
1823         const unsigned char *index_lookup;
1824         const unsigned int hashsz = the_hash_algo->rawsz;
1825         int index_lookup_width;
1826
1827         if (!index_fanout)
1828                 BUG("bsearch_pack called without a valid pack-index");
1829
1830         index_lookup = index_fanout + 4 * 256;
1831         if (p->index_version == 1) {
1832                 index_lookup_width = hashsz + 4;
1833                 index_lookup += 4;
1834         } else {
1835                 index_lookup_width = hashsz;
1836                 index_fanout += 8;
1837                 index_lookup += 8;
1838         }
1839
1840         return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1841                             index_lookup, index_lookup_width, result);
1842 }
1843
1844 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1845                                             uint32_t n)
1846 {
1847         const unsigned char *index = p->index_data;
1848         const unsigned int hashsz = the_hash_algo->rawsz;
1849         if (!index) {
1850                 if (open_pack_index(p))
1851                         return NULL;
1852                 index = p->index_data;
1853         }
1854         if (n >= p->num_objects)
1855                 return NULL;
1856         index += 4 * 256;
1857         if (p->index_version == 1) {
1858                 return index + (hashsz + 4) * n + 4;
1859         } else {
1860                 index += 8;
1861                 return index + hashsz * n;
1862         }
1863 }
1864
1865 const struct object_id *nth_packed_object_oid(struct object_id *oid,
1866                                               struct packed_git *p,
1867                                               uint32_t n)
1868 {
1869         const unsigned char *hash = nth_packed_object_sha1(p, n);
1870         if (!hash)
1871                 return NULL;
1872         hashcpy(oid->hash, hash);
1873         return oid;
1874 }
1875
1876 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1877 {
1878         const unsigned char *ptr = vptr;
1879         const unsigned char *start = p->index_data;
1880         const unsigned char *end = start + p->index_size;
1881         if (ptr < start)
1882                 die(_("offset before start of pack index for %s (corrupt index?)"),
1883                     p->pack_name);
1884         /* No need to check for underflow; .idx files must be at least 8 bytes */
1885         if (ptr >= end - 8)
1886                 die(_("offset beyond end of pack index for %s (truncated index?)"),
1887                     p->pack_name);
1888 }
1889
1890 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1891 {
1892         const unsigned char *index = p->index_data;
1893         const unsigned int hashsz = the_hash_algo->rawsz;
1894         index += 4 * 256;
1895         if (p->index_version == 1) {
1896                 return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
1897         } else {
1898                 uint32_t off;
1899                 index += 8 + p->num_objects * (hashsz + 4);
1900                 off = ntohl(*((uint32_t *)(index + 4 * n)));
1901                 if (!(off & 0x80000000))
1902                         return off;
1903                 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1904                 check_pack_index_ptr(p, index);
1905                 return get_be64(index);
1906         }
1907 }
1908
1909 off_t find_pack_entry_one(const unsigned char *sha1,
1910                                   struct packed_git *p)
1911 {
1912         const unsigned char *index = p->index_data;
1913         struct object_id oid;
1914         uint32_t result;
1915
1916         if (!index) {
1917                 if (open_pack_index(p))
1918                         return 0;
1919         }
1920
1921         hashcpy(oid.hash, sha1);
1922         if (bsearch_pack(&oid, p, &result))
1923                 return nth_packed_object_offset(p, result);
1924         return 0;
1925 }
1926
1927 int is_pack_valid(struct packed_git *p)
1928 {
1929         /* An already open pack is known to be valid. */
1930         if (p->pack_fd != -1)
1931                 return 1;
1932
1933         /* If the pack has one window completely covering the
1934          * file size, the pack is known to be valid even if
1935          * the descriptor is not currently open.
1936          */
1937         if (p->windows) {
1938                 struct pack_window *w = p->windows;
1939
1940                 if (!w->offset && w->len == p->pack_size)
1941                         return 1;
1942         }
1943
1944         /* Force the pack to open to prove its valid. */
1945         return !open_packed_git(p);
1946 }
1947
1948 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1949                                   struct packed_git *packs)
1950 {
1951         struct packed_git *p;
1952
1953         for (p = packs; p; p = p->next) {
1954                 if (find_pack_entry_one(sha1, p))
1955                         return p;
1956         }
1957         return NULL;
1958
1959 }
1960
1961 static int fill_pack_entry(const struct object_id *oid,
1962                            struct pack_entry *e,
1963                            struct packed_git *p)
1964 {
1965         off_t offset;
1966
1967         if (p->num_bad_objects) {
1968                 unsigned i;
1969                 for (i = 0; i < p->num_bad_objects; i++)
1970                         if (hasheq(oid->hash,
1971                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1972                                 return 0;
1973         }
1974
1975         offset = find_pack_entry_one(oid->hash, p);
1976         if (!offset)
1977                 return 0;
1978
1979         /*
1980          * We are about to tell the caller where they can locate the
1981          * requested object.  We better make sure the packfile is
1982          * still here and can be accessed before supplying that
1983          * answer, as it may have been deleted since the index was
1984          * loaded!
1985          */
1986         if (!is_pack_valid(p))
1987                 return 0;
1988         e->offset = offset;
1989         e->p = p;
1990         return 1;
1991 }
1992
1993 int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
1994 {
1995         struct list_head *pos;
1996         struct multi_pack_index *m;
1997
1998         prepare_packed_git(r);
1999         if (!r->objects->packed_git && !r->objects->multi_pack_index)
2000                 return 0;
2001
2002         for (m = r->objects->multi_pack_index; m; m = m->next) {
2003                 if (fill_midx_entry(r, oid, e, m))
2004                         return 1;
2005         }
2006
2007         list_for_each(pos, &r->objects->packed_git_mru) {
2008                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
2009                 if (!p->multi_pack_index && fill_pack_entry(oid, e, p)) {
2010                         list_move(&p->mru, &r->objects->packed_git_mru);
2011                         return 1;
2012                 }
2013         }
2014         return 0;
2015 }
2016
2017 int has_object_pack(const struct object_id *oid)
2018 {
2019         struct pack_entry e;
2020         return find_pack_entry(the_repository, oid, &e);
2021 }
2022
2023 int has_pack_index(const unsigned char *sha1)
2024 {
2025         struct stat st;
2026         if (stat(sha1_pack_index_name(sha1), &st))
2027                 return 0;
2028         return 1;
2029 }
2030
2031 int for_each_object_in_pack(struct packed_git *p,
2032                             each_packed_object_fn cb, void *data,
2033                             enum for_each_object_flags flags)
2034 {
2035         uint32_t i;
2036         int r = 0;
2037
2038         if (flags & FOR_EACH_OBJECT_PACK_ORDER) {
2039                 if (load_pack_revindex(p))
2040                         return -1;
2041         }
2042
2043         for (i = 0; i < p->num_objects; i++) {
2044                 uint32_t pos;
2045                 struct object_id oid;
2046
2047                 if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2048                         pos = p->revindex[i].nr;
2049                 else
2050                         pos = i;
2051
2052                 if (!nth_packed_object_oid(&oid, p, pos))
2053                         return error("unable to get sha1 of object %u in %s",
2054                                      pos, p->pack_name);
2055
2056                 r = cb(&oid, p, pos, data);
2057                 if (r)
2058                         break;
2059         }
2060         return r;
2061 }
2062
2063 int for_each_packed_object(each_packed_object_fn cb, void *data,
2064                            enum for_each_object_flags flags)
2065 {
2066         struct packed_git *p;
2067         int r = 0;
2068         int pack_errors = 0;
2069
2070         prepare_packed_git(the_repository);
2071         for (p = get_all_packs(the_repository); p; p = p->next) {
2072                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2073                         continue;
2074                 if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
2075                     !p->pack_promisor)
2076                         continue;
2077                 if (open_pack_index(p)) {
2078                         pack_errors = 1;
2079                         continue;
2080                 }
2081                 r = for_each_object_in_pack(p, cb, data, flags);
2082                 if (r)
2083                         break;
2084         }
2085         return r ? r : pack_errors;
2086 }
2087
2088 static int add_promisor_object(const struct object_id *oid,
2089                                struct packed_git *pack,
2090                                uint32_t pos,
2091                                void *set_)
2092 {
2093         struct oidset *set = set_;
2094         struct object *obj = parse_object(the_repository, oid);
2095         if (!obj)
2096                 return 1;
2097
2098         oidset_insert(set, oid);
2099
2100         /*
2101          * If this is a tree, commit, or tag, the objects it refers
2102          * to are also promisor objects. (Blobs refer to no objects->)
2103          */
2104         if (obj->type == OBJ_TREE) {
2105                 struct tree *tree = (struct tree *)obj;
2106                 struct tree_desc desc;
2107                 struct name_entry entry;
2108                 if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
2109                         /*
2110                          * Error messages are given when packs are
2111                          * verified, so do not print any here.
2112                          */
2113                         return 0;
2114                 while (tree_entry_gently(&desc, &entry))
2115                         oidset_insert(set, &entry.oid);
2116         } else if (obj->type == OBJ_COMMIT) {
2117                 struct commit *commit = (struct commit *) obj;
2118                 struct commit_list *parents = commit->parents;
2119
2120                 oidset_insert(set, get_commit_tree_oid(commit));
2121                 for (; parents; parents = parents->next)
2122                         oidset_insert(set, &parents->item->object.oid);
2123         } else if (obj->type == OBJ_TAG) {
2124                 struct tag *tag = (struct tag *) obj;
2125                 oidset_insert(set, get_tagged_oid(tag));
2126         }
2127         return 0;
2128 }
2129
2130 int is_promisor_object(const struct object_id *oid)
2131 {
2132         static struct oidset promisor_objects;
2133         static int promisor_objects_prepared;
2134
2135         if (!promisor_objects_prepared) {
2136                 if (has_promisor_remote()) {
2137                         for_each_packed_object(add_promisor_object,
2138                                                &promisor_objects,
2139                                                FOR_EACH_OBJECT_PROMISOR_ONLY);
2140                 }
2141                 promisor_objects_prepared = 1;
2142         }
2143         return oidset_contains(&promisor_objects, oid);
2144 }