Git 2.23.3
[git] / 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
21 char *odb_pack_name(struct strbuf *buf,
22                     const unsigned char *sha1,
23                     const char *ext)
24 {
25         strbuf_reset(buf);
26         strbuf_addf(buf, "%s/pack/pack-%s.%s", get_object_directory(),
27                     sha1_to_hex(sha1), ext);
28         return buf->buf;
29 }
30
31 char *sha1_pack_name(const unsigned char *sha1)
32 {
33         static struct strbuf buf = STRBUF_INIT;
34         return odb_pack_name(&buf, sha1, "pack");
35 }
36
37 char *sha1_pack_index_name(const unsigned char *sha1)
38 {
39         static struct strbuf buf = STRBUF_INIT;
40         return odb_pack_name(&buf, sha1, "idx");
41 }
42
43 static unsigned int pack_used_ctr;
44 static unsigned int pack_mmap_calls;
45 static unsigned int peak_pack_open_windows;
46 static unsigned int pack_open_windows;
47 static unsigned int pack_open_fds;
48 static unsigned int pack_max_fds;
49 static size_t peak_pack_mapped;
50 static size_t pack_mapped;
51
52 #define SZ_FMT PRIuMAX
53 static inline uintmax_t sz_fmt(size_t s) { return s; }
54
55 void pack_report(void)
56 {
57         fprintf(stderr,
58                 "pack_report: getpagesize()            = %10" SZ_FMT "\n"
59                 "pack_report: core.packedGitWindowSize = %10" SZ_FMT "\n"
60                 "pack_report: core.packedGitLimit      = %10" SZ_FMT "\n",
61                 sz_fmt(getpagesize()),
62                 sz_fmt(packed_git_window_size),
63                 sz_fmt(packed_git_limit));
64         fprintf(stderr,
65                 "pack_report: pack_used_ctr            = %10u\n"
66                 "pack_report: pack_mmap_calls          = %10u\n"
67                 "pack_report: pack_open_windows        = %10u / %10u\n"
68                 "pack_report: pack_mapped              = "
69                         "%10" SZ_FMT " / %10" SZ_FMT "\n",
70                 pack_used_ctr,
71                 pack_mmap_calls,
72                 pack_open_windows, peak_pack_open_windows,
73                 sz_fmt(pack_mapped), sz_fmt(peak_pack_mapped));
74 }
75
76 /*
77  * Open and mmap the index file at path, perform a couple of
78  * consistency checks, then record its information to p.  Return 0 on
79  * success.
80  */
81 static int check_packed_git_idx(const char *path, struct packed_git *p)
82 {
83         void *idx_map;
84         size_t idx_size;
85         int fd = git_open(path), ret;
86         struct stat st;
87         const unsigned int hashsz = the_hash_algo->rawsz;
88
89         if (fd < 0)
90                 return -1;
91         if (fstat(fd, &st)) {
92                 close(fd);
93                 return -1;
94         }
95         idx_size = xsize_t(st.st_size);
96         if (idx_size < 4 * 256 + hashsz + hashsz) {
97                 close(fd);
98                 return error("index file %s is too small", path);
99         }
100         idx_map = xmmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
101         close(fd);
102
103         ret = load_idx(path, hashsz, idx_map, idx_size, p);
104
105         if (ret)
106                 munmap(idx_map, idx_size);
107
108         return ret;
109 }
110
111 int load_idx(const char *path, const unsigned int hashsz, void *idx_map,
112              size_t idx_size, struct packed_git *p)
113 {
114         struct pack_idx_header *hdr = idx_map;
115         uint32_t version, nr, i, *index;
116
117         if (idx_size < 4 * 256 + hashsz + hashsz)
118                 return error("index file %s is too small", path);
119         if (idx_map == NULL)
120                 return error("empty data");
121
122         if (hdr->idx_signature == htonl(PACK_IDX_SIGNATURE)) {
123                 version = ntohl(hdr->idx_version);
124                 if (version < 2 || version > 2)
125                         return error("index file %s is version %"PRIu32
126                                      " and is not supported by this binary"
127                                      " (try upgrading GIT to a newer version)",
128                                      path, version);
129         } else
130                 version = 1;
131
132         nr = 0;
133         index = idx_map;
134         if (version > 1)
135                 index += 2;  /* skip index header */
136         for (i = 0; i < 256; i++) {
137                 uint32_t n = ntohl(index[i]);
138                 if (n < nr)
139                         return error("non-monotonic index %s", path);
140                 nr = n;
141         }
142
143         if (version == 1) {
144                 /*
145                  * Total size:
146                  *  - 256 index entries 4 bytes each
147                  *  - 24-byte entries * nr (object ID + 4-byte offset)
148                  *  - hash of the packfile
149                  *  - file checksum
150                  */
151                 if (idx_size != 4 * 256 + nr * (hashsz + 4) + hashsz + hashsz)
152                         return error("wrong index v1 file size in %s", path);
153         } else if (version == 2) {
154                 /*
155                  * Minimum size:
156                  *  - 8 bytes of header
157                  *  - 256 index entries 4 bytes each
158                  *  - object ID entry * nr
159                  *  - 4-byte crc entry * nr
160                  *  - 4-byte offset entry * nr
161                  *  - hash of the packfile
162                  *  - file checksum
163                  * And after the 4-byte offset table might be a
164                  * variable sized table containing 8-byte entries
165                  * for offsets larger than 2^31.
166                  */
167                 unsigned long min_size = 8 + 4*256 + nr*(hashsz + 4 + 4) + hashsz + hashsz;
168                 unsigned long max_size = min_size;
169                 if (nr)
170                         max_size += (nr - 1)*8;
171                 if (idx_size < min_size || idx_size > max_size)
172                         return error("wrong index v2 file size in %s", path);
173                 if (idx_size != min_size &&
174                     /*
175                      * make sure we can deal with large pack offsets.
176                      * 31-bit signed offset won't be enough, neither
177                      * 32-bit unsigned one will be.
178                      */
179                     (sizeof(off_t) <= 4))
180                         return error("pack too large for current definition of off_t in %s", path);
181         }
182
183         p->index_version = version;
184         p->index_data = idx_map;
185         p->index_size = idx_size;
186         p->num_objects = nr;
187         return 0;
188 }
189
190 int open_pack_index(struct packed_git *p)
191 {
192         char *idx_name;
193         size_t len;
194         int ret;
195
196         if (p->index_data)
197                 return 0;
198
199         if (!strip_suffix(p->pack_name, ".pack", &len))
200                 BUG("pack_name does not end in .pack");
201         idx_name = xstrfmt("%.*s.idx", (int)len, p->pack_name);
202         ret = check_packed_git_idx(idx_name, p);
203         free(idx_name);
204         return ret;
205 }
206
207 uint32_t get_pack_fanout(struct packed_git *p, uint32_t value)
208 {
209         const uint32_t *level1_ofs = p->index_data;
210
211         if (!level1_ofs) {
212                 if (open_pack_index(p))
213                         return 0;
214                 level1_ofs = p->index_data;
215         }
216
217         if (p->index_version > 1) {
218                 level1_ofs += 2;
219         }
220
221         return ntohl(level1_ofs[value]);
222 }
223
224 static struct packed_git *alloc_packed_git(int extra)
225 {
226         struct packed_git *p = xmalloc(st_add(sizeof(*p), extra));
227         memset(p, 0, sizeof(*p));
228         p->pack_fd = -1;
229         return p;
230 }
231
232 struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
233 {
234         const char *path = sha1_pack_name(sha1);
235         size_t alloc = st_add(strlen(path), 1);
236         struct packed_git *p = alloc_packed_git(alloc);
237
238         memcpy(p->pack_name, path, alloc); /* includes NUL */
239         hashcpy(p->hash, sha1);
240         if (check_packed_git_idx(idx_path, p)) {
241                 free(p);
242                 return NULL;
243         }
244
245         return p;
246 }
247
248 static void scan_windows(struct packed_git *p,
249         struct packed_git **lru_p,
250         struct pack_window **lru_w,
251         struct pack_window **lru_l)
252 {
253         struct pack_window *w, *w_l;
254
255         for (w_l = NULL, w = p->windows; w; w = w->next) {
256                 if (!w->inuse_cnt) {
257                         if (!*lru_w || w->last_used < (*lru_w)->last_used) {
258                                 *lru_p = p;
259                                 *lru_w = w;
260                                 *lru_l = w_l;
261                         }
262                 }
263                 w_l = w;
264         }
265 }
266
267 static int unuse_one_window(struct packed_git *current)
268 {
269         struct packed_git *p, *lru_p = NULL;
270         struct pack_window *lru_w = NULL, *lru_l = NULL;
271
272         if (current)
273                 scan_windows(current, &lru_p, &lru_w, &lru_l);
274         for (p = the_repository->objects->packed_git; p; p = p->next)
275                 scan_windows(p, &lru_p, &lru_w, &lru_l);
276         if (lru_p) {
277                 munmap(lru_w->base, lru_w->len);
278                 pack_mapped -= lru_w->len;
279                 if (lru_l)
280                         lru_l->next = lru_w->next;
281                 else
282                         lru_p->windows = lru_w->next;
283                 free(lru_w);
284                 pack_open_windows--;
285                 return 1;
286         }
287         return 0;
288 }
289
290 void release_pack_memory(size_t need)
291 {
292         size_t cur = pack_mapped;
293         while (need >= (cur - pack_mapped) && unuse_one_window(NULL))
294                 ; /* nothing */
295 }
296
297 void close_pack_windows(struct packed_git *p)
298 {
299         while (p->windows) {
300                 struct pack_window *w = p->windows;
301
302                 if (w->inuse_cnt)
303                         die("pack '%s' still has open windows to it",
304                             p->pack_name);
305                 munmap(w->base, w->len);
306                 pack_mapped -= w->len;
307                 pack_open_windows--;
308                 p->windows = w->next;
309                 free(w);
310         }
311 }
312
313 int close_pack_fd(struct packed_git *p)
314 {
315         if (p->pack_fd < 0)
316                 return 0;
317
318         close(p->pack_fd);
319         pack_open_fds--;
320         p->pack_fd = -1;
321
322         return 1;
323 }
324
325 void close_pack_index(struct packed_git *p)
326 {
327         if (p->index_data) {
328                 munmap((void *)p->index_data, p->index_size);
329                 p->index_data = NULL;
330         }
331 }
332
333 void close_pack(struct packed_git *p)
334 {
335         close_pack_windows(p);
336         close_pack_fd(p);
337         close_pack_index(p);
338 }
339
340 void close_object_store(struct raw_object_store *o)
341 {
342         struct packed_git *p;
343
344         for (p = o->packed_git; p; p = p->next)
345                 if (p->do_not_close)
346                         BUG("want to close pack marked 'do-not-close'");
347                 else
348                         close_pack(p);
349
350         if (o->multi_pack_index) {
351                 close_midx(o->multi_pack_index);
352                 o->multi_pack_index = NULL;
353         }
354
355         close_commit_graph(o);
356 }
357
358 void unlink_pack_path(const char *pack_name, int force_delete)
359 {
360         static const char *exts[] = {".pack", ".idx", ".keep", ".bitmap", ".promisor"};
361         int i;
362         struct strbuf buf = STRBUF_INIT;
363         size_t plen;
364
365         strbuf_addstr(&buf, pack_name);
366         strip_suffix_mem(buf.buf, &buf.len, ".pack");
367         plen = buf.len;
368
369         if (!force_delete) {
370                 strbuf_addstr(&buf, ".keep");
371                 if (!access(buf.buf, F_OK)) {
372                         strbuf_release(&buf);
373                         return;
374                 }
375         }
376
377         for (i = 0; i < ARRAY_SIZE(exts); i++) {
378                 strbuf_setlen(&buf, plen);
379                 strbuf_addstr(&buf, exts[i]);
380                 unlink(buf.buf);
381         }
382
383         strbuf_release(&buf);
384 }
385
386 /*
387  * The LRU pack is the one with the oldest MRU window, preferring packs
388  * with no used windows, or the oldest mtime if it has no windows allocated.
389  */
390 static void find_lru_pack(struct packed_git *p, struct packed_git **lru_p, struct pack_window **mru_w, int *accept_windows_inuse)
391 {
392         struct pack_window *w, *this_mru_w;
393         int has_windows_inuse = 0;
394
395         /*
396          * Reject this pack if it has windows and the previously selected
397          * one does not.  If this pack does not have windows, reject
398          * it if the pack file is newer than the previously selected one.
399          */
400         if (*lru_p && !*mru_w && (p->windows || p->mtime > (*lru_p)->mtime))
401                 return;
402
403         for (w = this_mru_w = p->windows; w; w = w->next) {
404                 /*
405                  * Reject this pack if any of its windows are in use,
406                  * but the previously selected pack did not have any
407                  * inuse windows.  Otherwise, record that this pack
408                  * has windows in use.
409                  */
410                 if (w->inuse_cnt) {
411                         if (*accept_windows_inuse)
412                                 has_windows_inuse = 1;
413                         else
414                                 return;
415                 }
416
417                 if (w->last_used > this_mru_w->last_used)
418                         this_mru_w = w;
419
420                 /*
421                  * Reject this pack if it has windows that have been
422                  * used more recently than the previously selected pack.
423                  * If the previously selected pack had windows inuse and
424                  * we have not encountered a window in this pack that is
425                  * inuse, skip this check since we prefer a pack with no
426                  * inuse windows to one that has inuse windows.
427                  */
428                 if (*mru_w && *accept_windows_inuse == has_windows_inuse &&
429                     this_mru_w->last_used > (*mru_w)->last_used)
430                         return;
431         }
432
433         /*
434          * Select this pack.
435          */
436         *mru_w = this_mru_w;
437         *lru_p = p;
438         *accept_windows_inuse = has_windows_inuse;
439 }
440
441 static int close_one_pack(void)
442 {
443         struct packed_git *p, *lru_p = NULL;
444         struct pack_window *mru_w = NULL;
445         int accept_windows_inuse = 1;
446
447         for (p = the_repository->objects->packed_git; p; p = p->next) {
448                 if (p->pack_fd == -1)
449                         continue;
450                 find_lru_pack(p, &lru_p, &mru_w, &accept_windows_inuse);
451         }
452
453         if (lru_p)
454                 return close_pack_fd(lru_p);
455
456         return 0;
457 }
458
459 static unsigned int get_max_fd_limit(void)
460 {
461 #ifdef RLIMIT_NOFILE
462         {
463                 struct rlimit lim;
464
465                 if (!getrlimit(RLIMIT_NOFILE, &lim))
466                         return lim.rlim_cur;
467         }
468 #endif
469
470 #ifdef _SC_OPEN_MAX
471         {
472                 long open_max = sysconf(_SC_OPEN_MAX);
473                 if (0 < open_max)
474                         return open_max;
475                 /*
476                  * Otherwise, we got -1 for one of the two
477                  * reasons:
478                  *
479                  * (1) sysconf() did not understand _SC_OPEN_MAX
480                  *     and signaled an error with -1; or
481                  * (2) sysconf() said there is no limit.
482                  *
483                  * We _could_ clear errno before calling sysconf() to
484                  * tell these two cases apart and return a huge number
485                  * in the latter case to let the caller cap it to a
486                  * value that is not so selfish, but letting the
487                  * fallback OPEN_MAX codepath take care of these cases
488                  * is a lot simpler.
489                  */
490         }
491 #endif
492
493 #ifdef OPEN_MAX
494         return OPEN_MAX;
495 #else
496         return 1; /* see the caller ;-) */
497 #endif
498 }
499
500 const char *pack_basename(struct packed_git *p)
501 {
502         const char *ret = strrchr(p->pack_name, '/');
503         if (ret)
504                 ret = ret + 1; /* skip past slash */
505         else
506                 ret = p->pack_name; /* we only have a base */
507         return ret;
508 }
509
510 /*
511  * Do not call this directly as this leaks p->pack_fd on error return;
512  * call open_packed_git() instead.
513  */
514 static int open_packed_git_1(struct packed_git *p)
515 {
516         struct stat st;
517         struct pack_header hdr;
518         unsigned char hash[GIT_MAX_RAWSZ];
519         unsigned char *idx_hash;
520         long fd_flag;
521         ssize_t read_result;
522         const unsigned hashsz = the_hash_algo->rawsz;
523
524         if (!p->index_data) {
525                 struct multi_pack_index *m;
526                 const char *pack_name = pack_basename(p);
527
528                 for (m = the_repository->objects->multi_pack_index;
529                      m; m = m->next) {
530                         if (midx_contains_pack(m, pack_name))
531                                 break;
532                 }
533
534                 if (!m && open_pack_index(p))
535                         return error("packfile %s index unavailable", p->pack_name);
536         }
537
538         if (!pack_max_fds) {
539                 unsigned int max_fds = get_max_fd_limit();
540
541                 /* Save 3 for stdin/stdout/stderr, 22 for work */
542                 if (25 < max_fds)
543                         pack_max_fds = max_fds - 25;
544                 else
545                         pack_max_fds = 1;
546         }
547
548         while (pack_max_fds <= pack_open_fds && close_one_pack())
549                 ; /* nothing */
550
551         p->pack_fd = git_open(p->pack_name);
552         if (p->pack_fd < 0 || fstat(p->pack_fd, &st))
553                 return -1;
554         pack_open_fds++;
555
556         /* If we created the struct before we had the pack we lack size. */
557         if (!p->pack_size) {
558                 if (!S_ISREG(st.st_mode))
559                         return error("packfile %s not a regular file", p->pack_name);
560                 p->pack_size = st.st_size;
561         } else if (p->pack_size != st.st_size)
562                 return error("packfile %s size changed", p->pack_name);
563
564         /* We leave these file descriptors open with sliding mmap;
565          * there is no point keeping them open across exec(), though.
566          */
567         fd_flag = fcntl(p->pack_fd, F_GETFD, 0);
568         if (fd_flag < 0)
569                 return error("cannot determine file descriptor flags");
570         fd_flag |= FD_CLOEXEC;
571         if (fcntl(p->pack_fd, F_SETFD, fd_flag) == -1)
572                 return error("cannot set FD_CLOEXEC");
573
574         /* Verify we recognize this pack file format. */
575         read_result = read_in_full(p->pack_fd, &hdr, sizeof(hdr));
576         if (read_result < 0)
577                 return error_errno("error reading from %s", p->pack_name);
578         if (read_result != sizeof(hdr))
579                 return error("file %s is far too short to be a packfile", p->pack_name);
580         if (hdr.hdr_signature != htonl(PACK_SIGNATURE))
581                 return error("file %s is not a GIT packfile", p->pack_name);
582         if (!pack_version_ok(hdr.hdr_version))
583                 return error("packfile %s is version %"PRIu32" and not"
584                         " supported (try upgrading GIT to a newer version)",
585                         p->pack_name, ntohl(hdr.hdr_version));
586
587         /* Skip index checking if in multi-pack-index */
588         if (!p->index_data)
589                 return 0;
590
591         /* Verify the pack matches its index. */
592         if (p->num_objects != ntohl(hdr.hdr_entries))
593                 return error("packfile %s claims to have %"PRIu32" objects"
594                              " while index indicates %"PRIu32" objects",
595                              p->pack_name, ntohl(hdr.hdr_entries),
596                              p->num_objects);
597         if (lseek(p->pack_fd, p->pack_size - hashsz, SEEK_SET) == -1)
598                 return error("end of packfile %s is unavailable", p->pack_name);
599         read_result = read_in_full(p->pack_fd, hash, hashsz);
600         if (read_result < 0)
601                 return error_errno("error reading from %s", p->pack_name);
602         if (read_result != hashsz)
603                 return error("packfile %s signature is unavailable", p->pack_name);
604         idx_hash = ((unsigned char *)p->index_data) + p->index_size - hashsz * 2;
605         if (!hasheq(hash, idx_hash))
606                 return error("packfile %s does not match index", p->pack_name);
607         return 0;
608 }
609
610 static int open_packed_git(struct packed_git *p)
611 {
612         if (!open_packed_git_1(p))
613                 return 0;
614         close_pack_fd(p);
615         return -1;
616 }
617
618 static int in_window(struct pack_window *win, off_t offset)
619 {
620         /* We must promise at least one full hash after the
621          * offset is available from this window, otherwise the offset
622          * is not actually in this window and a different window (which
623          * has that one hash excess) must be used.  This is to support
624          * the object header and delta base parsing routines below.
625          */
626         off_t win_off = win->offset;
627         return win_off <= offset
628                 && (offset + the_hash_algo->rawsz) <= (win_off + win->len);
629 }
630
631 unsigned char *use_pack(struct packed_git *p,
632                 struct pack_window **w_cursor,
633                 off_t offset,
634                 unsigned long *left)
635 {
636         struct pack_window *win = *w_cursor;
637
638         /* Since packfiles end in a hash of their content and it's
639          * pointless to ask for an offset into the middle of that
640          * hash, and the in_window function above wouldn't match
641          * don't allow an offset too close to the end of the file.
642          */
643         if (!p->pack_size && p->pack_fd == -1 && open_packed_git(p))
644                 die("packfile %s cannot be accessed", p->pack_name);
645         if (offset > (p->pack_size - the_hash_algo->rawsz))
646                 die("offset beyond end of packfile (truncated pack?)");
647         if (offset < 0)
648                 die(_("offset before end of packfile (broken .idx?)"));
649
650         if (!win || !in_window(win, offset)) {
651                 if (win)
652                         win->inuse_cnt--;
653                 for (win = p->windows; win; win = win->next) {
654                         if (in_window(win, offset))
655                                 break;
656                 }
657                 if (!win) {
658                         size_t window_align = packed_git_window_size / 2;
659                         off_t len;
660
661                         if (p->pack_fd == -1 && open_packed_git(p))
662                                 die("packfile %s cannot be accessed", p->pack_name);
663
664                         win = xcalloc(1, sizeof(*win));
665                         win->offset = (offset / window_align) * window_align;
666                         len = p->pack_size - win->offset;
667                         if (len > packed_git_window_size)
668                                 len = packed_git_window_size;
669                         win->len = (size_t)len;
670                         pack_mapped += win->len;
671                         while (packed_git_limit < pack_mapped
672                                 && unuse_one_window(p))
673                                 ; /* nothing */
674                         win->base = xmmap_gently(NULL, win->len,
675                                 PROT_READ, MAP_PRIVATE,
676                                 p->pack_fd, win->offset);
677                         if (win->base == MAP_FAILED)
678                                 die_errno("packfile %s cannot be mapped",
679                                           p->pack_name);
680                         if (!win->offset && win->len == p->pack_size
681                                 && !p->do_not_close)
682                                 close_pack_fd(p);
683                         pack_mmap_calls++;
684                         pack_open_windows++;
685                         if (pack_mapped > peak_pack_mapped)
686                                 peak_pack_mapped = pack_mapped;
687                         if (pack_open_windows > peak_pack_open_windows)
688                                 peak_pack_open_windows = pack_open_windows;
689                         win->next = p->windows;
690                         p->windows = win;
691                 }
692         }
693         if (win != *w_cursor) {
694                 win->last_used = pack_used_ctr++;
695                 win->inuse_cnt++;
696                 *w_cursor = win;
697         }
698         offset -= win->offset;
699         if (left)
700                 *left = win->len - xsize_t(offset);
701         return win->base + offset;
702 }
703
704 void unuse_pack(struct pack_window **w_cursor)
705 {
706         struct pack_window *w = *w_cursor;
707         if (w) {
708                 w->inuse_cnt--;
709                 *w_cursor = NULL;
710         }
711 }
712
713 static void try_to_free_pack_memory(size_t size)
714 {
715         release_pack_memory(size);
716 }
717
718 struct packed_git *add_packed_git(const char *path, size_t path_len, int local)
719 {
720         static int have_set_try_to_free_routine;
721         struct stat st;
722         size_t alloc;
723         struct packed_git *p;
724
725         if (!have_set_try_to_free_routine) {
726                 have_set_try_to_free_routine = 1;
727                 set_try_to_free_routine(try_to_free_pack_memory);
728         }
729
730         /*
731          * Make sure a corresponding .pack file exists and that
732          * the index looks sane.
733          */
734         if (!strip_suffix_mem(path, &path_len, ".idx"))
735                 return NULL;
736
737         /*
738          * ".promisor" is long enough to hold any suffix we're adding (and
739          * the use xsnprintf double-checks that)
740          */
741         alloc = st_add3(path_len, strlen(".promisor"), 1);
742         p = alloc_packed_git(alloc);
743         memcpy(p->pack_name, path, path_len);
744
745         xsnprintf(p->pack_name + path_len, alloc - path_len, ".keep");
746         if (!access(p->pack_name, F_OK))
747                 p->pack_keep = 1;
748
749         xsnprintf(p->pack_name + path_len, alloc - path_len, ".promisor");
750         if (!access(p->pack_name, F_OK))
751                 p->pack_promisor = 1;
752
753         xsnprintf(p->pack_name + path_len, alloc - path_len, ".pack");
754         if (stat(p->pack_name, &st) || !S_ISREG(st.st_mode)) {
755                 free(p);
756                 return NULL;
757         }
758
759         /* ok, it looks sane as far as we can check without
760          * actually mapping the pack file.
761          */
762         p->pack_size = st.st_size;
763         p->pack_local = local;
764         p->mtime = st.st_mtime;
765         if (path_len < the_hash_algo->hexsz ||
766             get_sha1_hex(path + path_len - the_hash_algo->hexsz, p->hash))
767                 hashclr(p->hash);
768         return p;
769 }
770
771 void install_packed_git(struct repository *r, struct packed_git *pack)
772 {
773         if (pack->pack_fd != -1)
774                 pack_open_fds++;
775
776         pack->next = r->objects->packed_git;
777         r->objects->packed_git = pack;
778 }
779
780 void (*report_garbage)(unsigned seen_bits, const char *path);
781
782 static void report_helper(const struct string_list *list,
783                           int seen_bits, int first, int last)
784 {
785         if (seen_bits == (PACKDIR_FILE_PACK|PACKDIR_FILE_IDX))
786                 return;
787
788         for (; first < last; first++)
789                 report_garbage(seen_bits, list->items[first].string);
790 }
791
792 static void report_pack_garbage(struct string_list *list)
793 {
794         int i, baselen = -1, first = 0, seen_bits = 0;
795
796         if (!report_garbage)
797                 return;
798
799         string_list_sort(list);
800
801         for (i = 0; i < list->nr; i++) {
802                 const char *path = list->items[i].string;
803                 if (baselen != -1 &&
804                     strncmp(path, list->items[first].string, baselen)) {
805                         report_helper(list, seen_bits, first, i);
806                         baselen = -1;
807                         seen_bits = 0;
808                 }
809                 if (baselen == -1) {
810                         const char *dot = strrchr(path, '.');
811                         if (!dot) {
812                                 report_garbage(PACKDIR_FILE_GARBAGE, path);
813                                 continue;
814                         }
815                         baselen = dot - path + 1;
816                         first = i;
817                 }
818                 if (!strcmp(path + baselen, "pack"))
819                         seen_bits |= 1;
820                 else if (!strcmp(path + baselen, "idx"))
821                         seen_bits |= 2;
822         }
823         report_helper(list, seen_bits, first, list->nr);
824 }
825
826 void for_each_file_in_pack_dir(const char *objdir,
827                                each_file_in_pack_dir_fn fn,
828                                void *data)
829 {
830         struct strbuf path = STRBUF_INIT;
831         size_t dirnamelen;
832         DIR *dir;
833         struct dirent *de;
834
835         strbuf_addstr(&path, objdir);
836         strbuf_addstr(&path, "/pack");
837         dir = opendir(path.buf);
838         if (!dir) {
839                 if (errno != ENOENT)
840                         error_errno("unable to open object pack directory: %s",
841                                     path.buf);
842                 strbuf_release(&path);
843                 return;
844         }
845         strbuf_addch(&path, '/');
846         dirnamelen = path.len;
847         while ((de = readdir(dir)) != NULL) {
848                 if (is_dot_or_dotdot(de->d_name))
849                         continue;
850
851                 strbuf_setlen(&path, dirnamelen);
852                 strbuf_addstr(&path, de->d_name);
853
854                 fn(path.buf, path.len, de->d_name, data);
855         }
856
857         closedir(dir);
858         strbuf_release(&path);
859 }
860
861 struct prepare_pack_data {
862         struct repository *r;
863         struct string_list *garbage;
864         int local;
865         struct multi_pack_index *m;
866 };
867
868 static void prepare_pack(const char *full_name, size_t full_name_len,
869                          const char *file_name, void *_data)
870 {
871         struct prepare_pack_data *data = (struct prepare_pack_data *)_data;
872         struct packed_git *p;
873         size_t base_len = full_name_len;
874
875         if (strip_suffix_mem(full_name, &base_len, ".idx") &&
876             !(data->m && midx_contains_pack(data->m, file_name))) {
877                 /* Don't reopen a pack we already have. */
878                 for (p = data->r->objects->packed_git; p; p = p->next) {
879                         size_t len;
880                         if (strip_suffix(p->pack_name, ".pack", &len) &&
881                             len == base_len &&
882                             !memcmp(p->pack_name, full_name, len))
883                                 break;
884                 }
885
886                 if (!p) {
887                         p = add_packed_git(full_name, full_name_len, data->local);
888                         if (p)
889                                 install_packed_git(data->r, p);
890                 }
891         }
892
893         if (!report_garbage)
894                 return;
895
896         if (!strcmp(file_name, "multi-pack-index"))
897                 return;
898         if (ends_with(file_name, ".idx") ||
899             ends_with(file_name, ".pack") ||
900             ends_with(file_name, ".bitmap") ||
901             ends_with(file_name, ".keep") ||
902             ends_with(file_name, ".promisor"))
903                 string_list_append(data->garbage, full_name);
904         else
905                 report_garbage(PACKDIR_FILE_GARBAGE, full_name);
906 }
907
908 static void prepare_packed_git_one(struct repository *r, char *objdir, int local)
909 {
910         struct prepare_pack_data data;
911         struct string_list garbage = STRING_LIST_INIT_DUP;
912
913         data.m = r->objects->multi_pack_index;
914
915         /* look for the multi-pack-index for this object directory */
916         while (data.m && strcmp(data.m->object_dir, objdir))
917                 data.m = data.m->next;
918
919         data.r = r;
920         data.garbage = &garbage;
921         data.local = local;
922
923         for_each_file_in_pack_dir(objdir, prepare_pack, &data);
924
925         report_pack_garbage(data.garbage);
926         string_list_clear(data.garbage, 0);
927 }
928
929 static void prepare_packed_git(struct repository *r);
930 /*
931  * Give a fast, rough count of the number of objects in the repository. This
932  * ignores loose objects completely. If you have a lot of them, then either
933  * you should repack because your performance will be awful, or they are
934  * all unreachable objects about to be pruned, in which case they're not really
935  * interesting as a measure of repo size in the first place.
936  */
937 unsigned long repo_approximate_object_count(struct repository *r)
938 {
939         if (!r->objects->approximate_object_count_valid) {
940                 unsigned long count;
941                 struct multi_pack_index *m;
942                 struct packed_git *p;
943
944                 prepare_packed_git(r);
945                 count = 0;
946                 for (m = get_multi_pack_index(r); m; m = m->next)
947                         count += m->num_objects;
948                 for (p = r->objects->packed_git; p; p = p->next) {
949                         if (open_pack_index(p))
950                                 continue;
951                         count += p->num_objects;
952                 }
953                 r->objects->approximate_object_count = count;
954         }
955         return r->objects->approximate_object_count;
956 }
957
958 static void *get_next_packed_git(const void *p)
959 {
960         return ((const struct packed_git *)p)->next;
961 }
962
963 static void set_next_packed_git(void *p, void *next)
964 {
965         ((struct packed_git *)p)->next = next;
966 }
967
968 static int sort_pack(const void *a_, const void *b_)
969 {
970         const struct packed_git *a = a_;
971         const struct packed_git *b = b_;
972         int st;
973
974         /*
975          * Local packs tend to contain objects specific to our
976          * variant of the project than remote ones.  In addition,
977          * remote ones could be on a network mounted filesystem.
978          * Favor local ones for these reasons.
979          */
980         st = a->pack_local - b->pack_local;
981         if (st)
982                 return -st;
983
984         /*
985          * Younger packs tend to contain more recent objects,
986          * and more recent objects tend to get accessed more
987          * often.
988          */
989         if (a->mtime < b->mtime)
990                 return 1;
991         else if (a->mtime == b->mtime)
992                 return 0;
993         return -1;
994 }
995
996 static void rearrange_packed_git(struct repository *r)
997 {
998         r->objects->packed_git = llist_mergesort(
999                 r->objects->packed_git, get_next_packed_git,
1000                 set_next_packed_git, sort_pack);
1001 }
1002
1003 static void prepare_packed_git_mru(struct repository *r)
1004 {
1005         struct packed_git *p;
1006
1007         INIT_LIST_HEAD(&r->objects->packed_git_mru);
1008
1009         for (p = r->objects->packed_git; p; p = p->next)
1010                 list_add_tail(&p->mru, &r->objects->packed_git_mru);
1011 }
1012
1013 static void prepare_packed_git(struct repository *r)
1014 {
1015         struct object_directory *odb;
1016
1017         if (r->objects->packed_git_initialized)
1018                 return;
1019
1020         prepare_alt_odb(r);
1021         for (odb = r->objects->odb; odb; odb = odb->next) {
1022                 int local = (odb == r->objects->odb);
1023                 prepare_multi_pack_index_one(r, odb->path, local);
1024                 prepare_packed_git_one(r, odb->path, local);
1025         }
1026         rearrange_packed_git(r);
1027
1028         prepare_packed_git_mru(r);
1029         r->objects->packed_git_initialized = 1;
1030 }
1031
1032 void reprepare_packed_git(struct repository *r)
1033 {
1034         struct object_directory *odb;
1035
1036         for (odb = r->objects->odb; odb; odb = odb->next)
1037                 odb_clear_loose_cache(odb);
1038
1039         r->objects->approximate_object_count_valid = 0;
1040         r->objects->packed_git_initialized = 0;
1041         prepare_packed_git(r);
1042 }
1043
1044 struct packed_git *get_packed_git(struct repository *r)
1045 {
1046         prepare_packed_git(r);
1047         return r->objects->packed_git;
1048 }
1049
1050 struct multi_pack_index *get_multi_pack_index(struct repository *r)
1051 {
1052         prepare_packed_git(r);
1053         return r->objects->multi_pack_index;
1054 }
1055
1056 struct packed_git *get_all_packs(struct repository *r)
1057 {
1058         struct multi_pack_index *m;
1059
1060         prepare_packed_git(r);
1061         for (m = r->objects->multi_pack_index; m; m = m->next) {
1062                 uint32_t i;
1063                 for (i = 0; i < m->num_packs; i++)
1064                         prepare_midx_pack(r, m, i);
1065         }
1066
1067         return r->objects->packed_git;
1068 }
1069
1070 struct list_head *get_packed_git_mru(struct repository *r)
1071 {
1072         prepare_packed_git(r);
1073         return &r->objects->packed_git_mru;
1074 }
1075
1076 unsigned long unpack_object_header_buffer(const unsigned char *buf,
1077                 unsigned long len, enum object_type *type, unsigned long *sizep)
1078 {
1079         unsigned shift;
1080         unsigned long size, c;
1081         unsigned long used = 0;
1082
1083         c = buf[used++];
1084         *type = (c >> 4) & 7;
1085         size = c & 15;
1086         shift = 4;
1087         while (c & 0x80) {
1088                 if (len <= used || bitsizeof(long) <= shift) {
1089                         error("bad object header");
1090                         size = used = 0;
1091                         break;
1092                 }
1093                 c = buf[used++];
1094                 size += (c & 0x7f) << shift;
1095                 shift += 7;
1096         }
1097         *sizep = size;
1098         return used;
1099 }
1100
1101 unsigned long get_size_from_delta(struct packed_git *p,
1102                                   struct pack_window **w_curs,
1103                                   off_t curpos)
1104 {
1105         const unsigned char *data;
1106         unsigned char delta_head[20], *in;
1107         git_zstream stream;
1108         int st;
1109
1110         memset(&stream, 0, sizeof(stream));
1111         stream.next_out = delta_head;
1112         stream.avail_out = sizeof(delta_head);
1113
1114         git_inflate_init(&stream);
1115         do {
1116                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1117                 stream.next_in = in;
1118                 st = git_inflate(&stream, Z_FINISH);
1119                 curpos += stream.next_in - in;
1120         } while ((st == Z_OK || st == Z_BUF_ERROR) &&
1121                  stream.total_out < sizeof(delta_head));
1122         git_inflate_end(&stream);
1123         if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head)) {
1124                 error("delta data unpack-initial failed");
1125                 return 0;
1126         }
1127
1128         /* Examine the initial part of the delta to figure out
1129          * the result size.
1130          */
1131         data = delta_head;
1132
1133         /* ignore base size */
1134         get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1135
1136         /* Read the result size */
1137         return get_delta_hdr_size(&data, delta_head+sizeof(delta_head));
1138 }
1139
1140 int unpack_object_header(struct packed_git *p,
1141                          struct pack_window **w_curs,
1142                          off_t *curpos,
1143                          unsigned long *sizep)
1144 {
1145         unsigned char *base;
1146         unsigned long left;
1147         unsigned long used;
1148         enum object_type type;
1149
1150         /* use_pack() assures us we have [base, base + 20) available
1151          * as a range that we can look at.  (Its actually the hash
1152          * size that is assured.)  With our object header encoding
1153          * the maximum deflated object size is 2^137, which is just
1154          * insane, so we know won't exceed what we have been given.
1155          */
1156         base = use_pack(p, w_curs, *curpos, &left);
1157         used = unpack_object_header_buffer(base, left, &type, sizep);
1158         if (!used) {
1159                 type = OBJ_BAD;
1160         } else
1161                 *curpos += used;
1162
1163         return type;
1164 }
1165
1166 void mark_bad_packed_object(struct packed_git *p, const unsigned char *sha1)
1167 {
1168         unsigned i;
1169         const unsigned hashsz = the_hash_algo->rawsz;
1170         for (i = 0; i < p->num_bad_objects; i++)
1171                 if (hasheq(sha1, p->bad_object_sha1 + hashsz * i))
1172                         return;
1173         p->bad_object_sha1 = xrealloc(p->bad_object_sha1,
1174                                       st_mult(GIT_MAX_RAWSZ,
1175                                               st_add(p->num_bad_objects, 1)));
1176         hashcpy(p->bad_object_sha1 + hashsz * p->num_bad_objects, sha1);
1177         p->num_bad_objects++;
1178 }
1179
1180 const struct packed_git *has_packed_and_bad(struct repository *r,
1181                                             const unsigned char *sha1)
1182 {
1183         struct packed_git *p;
1184         unsigned i;
1185
1186         for (p = r->objects->packed_git; p; p = p->next)
1187                 for (i = 0; i < p->num_bad_objects; i++)
1188                         if (hasheq(sha1,
1189                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1190                                 return p;
1191         return NULL;
1192 }
1193
1194 static off_t get_delta_base(struct packed_git *p,
1195                                     struct pack_window **w_curs,
1196                                     off_t *curpos,
1197                                     enum object_type type,
1198                                     off_t delta_obj_offset)
1199 {
1200         unsigned char *base_info = use_pack(p, w_curs, *curpos, NULL);
1201         off_t base_offset;
1202
1203         /* use_pack() assured us we have [base_info, base_info + 20)
1204          * as a range that we can look at without walking off the
1205          * end of the mapped window.  Its actually the hash size
1206          * that is assured.  An OFS_DELTA longer than the hash size
1207          * is stupid, as then a REF_DELTA would be smaller to store.
1208          */
1209         if (type == OBJ_OFS_DELTA) {
1210                 unsigned used = 0;
1211                 unsigned char c = base_info[used++];
1212                 base_offset = c & 127;
1213                 while (c & 128) {
1214                         base_offset += 1;
1215                         if (!base_offset || MSB(base_offset, 7))
1216                                 return 0;  /* overflow */
1217                         c = base_info[used++];
1218                         base_offset = (base_offset << 7) + (c & 127);
1219                 }
1220                 base_offset = delta_obj_offset - base_offset;
1221                 if (base_offset <= 0 || base_offset >= delta_obj_offset)
1222                         return 0;  /* out of bound */
1223                 *curpos += used;
1224         } else if (type == OBJ_REF_DELTA) {
1225                 /* The base entry _must_ be in the same pack */
1226                 base_offset = find_pack_entry_one(base_info, p);
1227                 *curpos += the_hash_algo->rawsz;
1228         } else
1229                 die("I am totally screwed");
1230         return base_offset;
1231 }
1232
1233 /*
1234  * Like get_delta_base above, but we return the sha1 instead of the pack
1235  * offset. This means it is cheaper for REF deltas (we do not have to do
1236  * the final object lookup), but more expensive for OFS deltas (we
1237  * have to load the revidx to convert the offset back into a sha1).
1238  */
1239 static const unsigned char *get_delta_base_sha1(struct packed_git *p,
1240                                                 struct pack_window **w_curs,
1241                                                 off_t curpos,
1242                                                 enum object_type type,
1243                                                 off_t delta_obj_offset)
1244 {
1245         if (type == OBJ_REF_DELTA) {
1246                 unsigned char *base = use_pack(p, w_curs, curpos, NULL);
1247                 return base;
1248         } else if (type == OBJ_OFS_DELTA) {
1249                 struct revindex_entry *revidx;
1250                 off_t base_offset = get_delta_base(p, w_curs, &curpos,
1251                                                    type, delta_obj_offset);
1252
1253                 if (!base_offset)
1254                         return NULL;
1255
1256                 revidx = find_pack_revindex(p, base_offset);
1257                 if (!revidx)
1258                         return NULL;
1259
1260                 return nth_packed_object_sha1(p, revidx->nr);
1261         } else
1262                 return NULL;
1263 }
1264
1265 static int retry_bad_packed_offset(struct repository *r,
1266                                    struct packed_git *p,
1267                                    off_t obj_offset)
1268 {
1269         int type;
1270         struct revindex_entry *revidx;
1271         struct object_id oid;
1272         revidx = find_pack_revindex(p, obj_offset);
1273         if (!revidx)
1274                 return OBJ_BAD;
1275         nth_packed_object_oid(&oid, p, revidx->nr);
1276         mark_bad_packed_object(p, oid.hash);
1277         type = oid_object_info(r, &oid, NULL);
1278         if (type <= OBJ_NONE)
1279                 return OBJ_BAD;
1280         return type;
1281 }
1282
1283 #define POI_STACK_PREALLOC 64
1284
1285 static enum object_type packed_to_object_type(struct repository *r,
1286                                               struct packed_git *p,
1287                                               off_t obj_offset,
1288                                               enum object_type type,
1289                                               struct pack_window **w_curs,
1290                                               off_t curpos)
1291 {
1292         off_t small_poi_stack[POI_STACK_PREALLOC];
1293         off_t *poi_stack = small_poi_stack;
1294         int poi_stack_nr = 0, poi_stack_alloc = POI_STACK_PREALLOC;
1295
1296         while (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1297                 off_t base_offset;
1298                 unsigned long size;
1299                 /* Push the object we're going to leave behind */
1300                 if (poi_stack_nr >= poi_stack_alloc && poi_stack == small_poi_stack) {
1301                         poi_stack_alloc = alloc_nr(poi_stack_nr);
1302                         ALLOC_ARRAY(poi_stack, poi_stack_alloc);
1303                         COPY_ARRAY(poi_stack, small_poi_stack, poi_stack_nr);
1304                 } else {
1305                         ALLOC_GROW(poi_stack, poi_stack_nr+1, poi_stack_alloc);
1306                 }
1307                 poi_stack[poi_stack_nr++] = obj_offset;
1308                 /* If parsing the base offset fails, just unwind */
1309                 base_offset = get_delta_base(p, w_curs, &curpos, type, obj_offset);
1310                 if (!base_offset)
1311                         goto unwind;
1312                 curpos = obj_offset = base_offset;
1313                 type = unpack_object_header(p, w_curs, &curpos, &size);
1314                 if (type <= OBJ_NONE) {
1315                         /* If getting the base itself fails, we first
1316                          * retry the base, otherwise unwind */
1317                         type = retry_bad_packed_offset(r, p, base_offset);
1318                         if (type > OBJ_NONE)
1319                                 goto out;
1320                         goto unwind;
1321                 }
1322         }
1323
1324         switch (type) {
1325         case OBJ_BAD:
1326         case OBJ_COMMIT:
1327         case OBJ_TREE:
1328         case OBJ_BLOB:
1329         case OBJ_TAG:
1330                 break;
1331         default:
1332                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1333                       type, (uintmax_t)obj_offset, p->pack_name);
1334                 type = OBJ_BAD;
1335         }
1336
1337 out:
1338         if (poi_stack != small_poi_stack)
1339                 free(poi_stack);
1340         return type;
1341
1342 unwind:
1343         while (poi_stack_nr) {
1344                 obj_offset = poi_stack[--poi_stack_nr];
1345                 type = retry_bad_packed_offset(r, p, obj_offset);
1346                 if (type > OBJ_NONE)
1347                         goto out;
1348         }
1349         type = OBJ_BAD;
1350         goto out;
1351 }
1352
1353 static struct hashmap delta_base_cache;
1354 static size_t delta_base_cached;
1355
1356 static LIST_HEAD(delta_base_cache_lru);
1357
1358 struct delta_base_cache_key {
1359         struct packed_git *p;
1360         off_t base_offset;
1361 };
1362
1363 struct delta_base_cache_entry {
1364         struct hashmap hash;
1365         struct delta_base_cache_key key;
1366         struct list_head lru;
1367         void *data;
1368         unsigned long size;
1369         enum object_type type;
1370 };
1371
1372 static unsigned int pack_entry_hash(struct packed_git *p, off_t base_offset)
1373 {
1374         unsigned int hash;
1375
1376         hash = (unsigned int)(intptr_t)p + (unsigned int)base_offset;
1377         hash += (hash >> 8) + (hash >> 16);
1378         return hash;
1379 }
1380
1381 static struct delta_base_cache_entry *
1382 get_delta_base_cache_entry(struct packed_git *p, off_t base_offset)
1383 {
1384         struct hashmap_entry entry;
1385         struct delta_base_cache_key key;
1386
1387         if (!delta_base_cache.cmpfn)
1388                 return NULL;
1389
1390         hashmap_entry_init(&entry, pack_entry_hash(p, base_offset));
1391         key.p = p;
1392         key.base_offset = base_offset;
1393         return hashmap_get(&delta_base_cache, &entry, &key);
1394 }
1395
1396 static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
1397                                    const struct delta_base_cache_key *b)
1398 {
1399         return a->p == b->p && a->base_offset == b->base_offset;
1400 }
1401
1402 static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
1403                                      const void *va, const void *vb,
1404                                      const void *vkey)
1405 {
1406         const struct delta_base_cache_entry *a = va, *b = vb;
1407         const struct delta_base_cache_key *key = vkey;
1408         if (key)
1409                 return !delta_base_cache_key_eq(&a->key, key);
1410         else
1411                 return !delta_base_cache_key_eq(&a->key, &b->key);
1412 }
1413
1414 static int in_delta_base_cache(struct packed_git *p, off_t base_offset)
1415 {
1416         return !!get_delta_base_cache_entry(p, base_offset);
1417 }
1418
1419 /*
1420  * Remove the entry from the cache, but do _not_ free the associated
1421  * entry data. The caller takes ownership of the "data" buffer, and
1422  * should copy out any fields it wants before detaching.
1423  */
1424 static void detach_delta_base_cache_entry(struct delta_base_cache_entry *ent)
1425 {
1426         hashmap_remove(&delta_base_cache, ent, &ent->key);
1427         list_del(&ent->lru);
1428         delta_base_cached -= ent->size;
1429         free(ent);
1430 }
1431
1432 static void *cache_or_unpack_entry(struct repository *r, struct packed_git *p,
1433                                    off_t base_offset, unsigned long *base_size,
1434                                    enum object_type *type)
1435 {
1436         struct delta_base_cache_entry *ent;
1437
1438         ent = get_delta_base_cache_entry(p, base_offset);
1439         if (!ent)
1440                 return unpack_entry(r, p, base_offset, type, base_size);
1441
1442         if (type)
1443                 *type = ent->type;
1444         if (base_size)
1445                 *base_size = ent->size;
1446         return xmemdupz(ent->data, ent->size);
1447 }
1448
1449 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
1450 {
1451         free(ent->data);
1452         detach_delta_base_cache_entry(ent);
1453 }
1454
1455 void clear_delta_base_cache(void)
1456 {
1457         struct list_head *lru, *tmp;
1458         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1459                 struct delta_base_cache_entry *entry =
1460                         list_entry(lru, struct delta_base_cache_entry, lru);
1461                 release_delta_base_cache(entry);
1462         }
1463 }
1464
1465 static void add_delta_base_cache(struct packed_git *p, off_t base_offset,
1466         void *base, unsigned long base_size, enum object_type type)
1467 {
1468         struct delta_base_cache_entry *ent = xmalloc(sizeof(*ent));
1469         struct list_head *lru, *tmp;
1470
1471         delta_base_cached += base_size;
1472
1473         list_for_each_safe(lru, tmp, &delta_base_cache_lru) {
1474                 struct delta_base_cache_entry *f =
1475                         list_entry(lru, struct delta_base_cache_entry, lru);
1476                 if (delta_base_cached <= delta_base_cache_limit)
1477                         break;
1478                 release_delta_base_cache(f);
1479         }
1480
1481         ent->key.p = p;
1482         ent->key.base_offset = base_offset;
1483         ent->type = type;
1484         ent->data = base;
1485         ent->size = base_size;
1486         list_add_tail(&ent->lru, &delta_base_cache_lru);
1487
1488         if (!delta_base_cache.cmpfn)
1489                 hashmap_init(&delta_base_cache, delta_base_cache_hash_cmp, NULL, 0);
1490         hashmap_entry_init(ent, pack_entry_hash(p, base_offset));
1491         hashmap_add(&delta_base_cache, ent);
1492 }
1493
1494 int packed_object_info(struct repository *r, struct packed_git *p,
1495                        off_t obj_offset, struct object_info *oi)
1496 {
1497         struct pack_window *w_curs = NULL;
1498         unsigned long size;
1499         off_t curpos = obj_offset;
1500         enum object_type type;
1501
1502         /*
1503          * We always get the representation type, but only convert it to
1504          * a "real" type later if the caller is interested.
1505          */
1506         if (oi->contentp) {
1507                 *oi->contentp = cache_or_unpack_entry(r, p, obj_offset, oi->sizep,
1508                                                       &type);
1509                 if (!*oi->contentp)
1510                         type = OBJ_BAD;
1511         } else {
1512                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1513         }
1514
1515         if (!oi->contentp && oi->sizep) {
1516                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1517                         off_t tmp_pos = curpos;
1518                         off_t base_offset = get_delta_base(p, &w_curs, &tmp_pos,
1519                                                            type, obj_offset);
1520                         if (!base_offset) {
1521                                 type = OBJ_BAD;
1522                                 goto out;
1523                         }
1524                         *oi->sizep = get_size_from_delta(p, &w_curs, tmp_pos);
1525                         if (*oi->sizep == 0) {
1526                                 type = OBJ_BAD;
1527                                 goto out;
1528                         }
1529                 } else {
1530                         *oi->sizep = size;
1531                 }
1532         }
1533
1534         if (oi->disk_sizep) {
1535                 struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1536                 *oi->disk_sizep = revidx[1].offset - obj_offset;
1537         }
1538
1539         if (oi->typep || oi->type_name) {
1540                 enum object_type ptot;
1541                 ptot = packed_to_object_type(r, p, obj_offset,
1542                                              type, &w_curs, curpos);
1543                 if (oi->typep)
1544                         *oi->typep = ptot;
1545                 if (oi->type_name) {
1546                         const char *tn = type_name(ptot);
1547                         if (tn)
1548                                 strbuf_addstr(oi->type_name, tn);
1549                 }
1550                 if (ptot < 0) {
1551                         type = OBJ_BAD;
1552                         goto out;
1553                 }
1554         }
1555
1556         if (oi->delta_base_sha1) {
1557                 if (type == OBJ_OFS_DELTA || type == OBJ_REF_DELTA) {
1558                         const unsigned char *base;
1559
1560                         base = get_delta_base_sha1(p, &w_curs, curpos,
1561                                                    type, obj_offset);
1562                         if (!base) {
1563                                 type = OBJ_BAD;
1564                                 goto out;
1565                         }
1566
1567                         hashcpy(oi->delta_base_sha1, base);
1568                 } else
1569                         hashclr(oi->delta_base_sha1);
1570         }
1571
1572         oi->whence = in_delta_base_cache(p, obj_offset) ? OI_DBCACHED :
1573                                                           OI_PACKED;
1574
1575 out:
1576         unuse_pack(&w_curs);
1577         return type;
1578 }
1579
1580 static void *unpack_compressed_entry(struct packed_git *p,
1581                                     struct pack_window **w_curs,
1582                                     off_t curpos,
1583                                     unsigned long size)
1584 {
1585         int st;
1586         git_zstream stream;
1587         unsigned char *buffer, *in;
1588
1589         buffer = xmallocz_gently(size);
1590         if (!buffer)
1591                 return NULL;
1592         memset(&stream, 0, sizeof(stream));
1593         stream.next_out = buffer;
1594         stream.avail_out = size + 1;
1595
1596         git_inflate_init(&stream);
1597         do {
1598                 in = use_pack(p, w_curs, curpos, &stream.avail_in);
1599                 stream.next_in = in;
1600                 st = git_inflate(&stream, Z_FINISH);
1601                 if (!stream.avail_out)
1602                         break; /* the payload is larger than it should be */
1603                 curpos += stream.next_in - in;
1604         } while (st == Z_OK || st == Z_BUF_ERROR);
1605         git_inflate_end(&stream);
1606         if ((st != Z_STREAM_END) || stream.total_out != size) {
1607                 free(buffer);
1608                 return NULL;
1609         }
1610
1611         /* versions of zlib can clobber unconsumed portion of outbuf */
1612         buffer[size] = '\0';
1613
1614         return buffer;
1615 }
1616
1617 static void write_pack_access_log(struct packed_git *p, off_t obj_offset)
1618 {
1619         static struct trace_key pack_access = TRACE_KEY_INIT(PACK_ACCESS);
1620         trace_printf_key(&pack_access, "%s %"PRIuMAX"\n",
1621                          p->pack_name, (uintmax_t)obj_offset);
1622 }
1623
1624 int do_check_packed_object_crc;
1625
1626 #define UNPACK_ENTRY_STACK_PREALLOC 64
1627 struct unpack_entry_stack_ent {
1628         off_t obj_offset;
1629         off_t curpos;
1630         unsigned long size;
1631 };
1632
1633 static void *read_object(struct repository *r,
1634                          const struct object_id *oid,
1635                          enum object_type *type,
1636                          unsigned long *size)
1637 {
1638         struct object_info oi = OBJECT_INFO_INIT;
1639         void *content;
1640         oi.typep = type;
1641         oi.sizep = size;
1642         oi.contentp = &content;
1643
1644         if (oid_object_info_extended(r, oid, &oi, 0) < 0)
1645                 return NULL;
1646         return content;
1647 }
1648
1649 void *unpack_entry(struct repository *r, struct packed_git *p, off_t obj_offset,
1650                    enum object_type *final_type, unsigned long *final_size)
1651 {
1652         struct pack_window *w_curs = NULL;
1653         off_t curpos = obj_offset;
1654         void *data = NULL;
1655         unsigned long size;
1656         enum object_type type;
1657         struct unpack_entry_stack_ent small_delta_stack[UNPACK_ENTRY_STACK_PREALLOC];
1658         struct unpack_entry_stack_ent *delta_stack = small_delta_stack;
1659         int delta_stack_nr = 0, delta_stack_alloc = UNPACK_ENTRY_STACK_PREALLOC;
1660         int base_from_cache = 0;
1661
1662         write_pack_access_log(p, obj_offset);
1663
1664         /* PHASE 1: drill down to the innermost base object */
1665         for (;;) {
1666                 off_t base_offset;
1667                 int i;
1668                 struct delta_base_cache_entry *ent;
1669
1670                 ent = get_delta_base_cache_entry(p, curpos);
1671                 if (ent) {
1672                         type = ent->type;
1673                         data = ent->data;
1674                         size = ent->size;
1675                         detach_delta_base_cache_entry(ent);
1676                         base_from_cache = 1;
1677                         break;
1678                 }
1679
1680                 if (do_check_packed_object_crc && p->index_version > 1) {
1681                         struct revindex_entry *revidx = find_pack_revindex(p, obj_offset);
1682                         off_t len = revidx[1].offset - obj_offset;
1683                         if (check_pack_crc(p, &w_curs, obj_offset, len, revidx->nr)) {
1684                                 struct object_id oid;
1685                                 nth_packed_object_oid(&oid, p, revidx->nr);
1686                                 error("bad packed object CRC for %s",
1687                                       oid_to_hex(&oid));
1688                                 mark_bad_packed_object(p, oid.hash);
1689                                 data = NULL;
1690                                 goto out;
1691                         }
1692                 }
1693
1694                 type = unpack_object_header(p, &w_curs, &curpos, &size);
1695                 if (type != OBJ_OFS_DELTA && type != OBJ_REF_DELTA)
1696                         break;
1697
1698                 base_offset = get_delta_base(p, &w_curs, &curpos, type, obj_offset);
1699                 if (!base_offset) {
1700                         error("failed to validate delta base reference "
1701                               "at offset %"PRIuMAX" from %s",
1702                               (uintmax_t)curpos, p->pack_name);
1703                         /* bail to phase 2, in hopes of recovery */
1704                         data = NULL;
1705                         break;
1706                 }
1707
1708                 /* push object, proceed to base */
1709                 if (delta_stack_nr >= delta_stack_alloc
1710                     && delta_stack == small_delta_stack) {
1711                         delta_stack_alloc = alloc_nr(delta_stack_nr);
1712                         ALLOC_ARRAY(delta_stack, delta_stack_alloc);
1713                         COPY_ARRAY(delta_stack, small_delta_stack,
1714                                    delta_stack_nr);
1715                 } else {
1716                         ALLOC_GROW(delta_stack, delta_stack_nr+1, delta_stack_alloc);
1717                 }
1718                 i = delta_stack_nr++;
1719                 delta_stack[i].obj_offset = obj_offset;
1720                 delta_stack[i].curpos = curpos;
1721                 delta_stack[i].size = size;
1722
1723                 curpos = obj_offset = base_offset;
1724         }
1725
1726         /* PHASE 2: handle the base */
1727         switch (type) {
1728         case OBJ_OFS_DELTA:
1729         case OBJ_REF_DELTA:
1730                 if (data)
1731                         BUG("unpack_entry: left loop at a valid delta");
1732                 break;
1733         case OBJ_COMMIT:
1734         case OBJ_TREE:
1735         case OBJ_BLOB:
1736         case OBJ_TAG:
1737                 if (!base_from_cache)
1738                         data = unpack_compressed_entry(p, &w_curs, curpos, size);
1739                 break;
1740         default:
1741                 data = NULL;
1742                 error("unknown object type %i at offset %"PRIuMAX" in %s",
1743                       type, (uintmax_t)obj_offset, p->pack_name);
1744         }
1745
1746         /* PHASE 3: apply deltas in order */
1747
1748         /* invariants:
1749          *   'data' holds the base data, or NULL if there was corruption
1750          */
1751         while (delta_stack_nr) {
1752                 void *delta_data;
1753                 void *base = data;
1754                 void *external_base = NULL;
1755                 unsigned long delta_size, base_size = size;
1756                 int i;
1757
1758                 data = NULL;
1759
1760                 if (base)
1761                         add_delta_base_cache(p, obj_offset, base, base_size, type);
1762
1763                 if (!base) {
1764                         /*
1765                          * We're probably in deep shit, but let's try to fetch
1766                          * the required base anyway from another pack or loose.
1767                          * This is costly but should happen only in the presence
1768                          * of a corrupted pack, and is better than failing outright.
1769                          */
1770                         struct revindex_entry *revidx;
1771                         struct object_id base_oid;
1772                         revidx = find_pack_revindex(p, obj_offset);
1773                         if (revidx) {
1774                                 nth_packed_object_oid(&base_oid, p, revidx->nr);
1775                                 error("failed to read delta base object %s"
1776                                       " at offset %"PRIuMAX" from %s",
1777                                       oid_to_hex(&base_oid), (uintmax_t)obj_offset,
1778                                       p->pack_name);
1779                                 mark_bad_packed_object(p, base_oid.hash);
1780                                 base = read_object(r, &base_oid, &type, &base_size);
1781                                 external_base = base;
1782                         }
1783                 }
1784
1785                 i = --delta_stack_nr;
1786                 obj_offset = delta_stack[i].obj_offset;
1787                 curpos = delta_stack[i].curpos;
1788                 delta_size = delta_stack[i].size;
1789
1790                 if (!base)
1791                         continue;
1792
1793                 delta_data = unpack_compressed_entry(p, &w_curs, curpos, delta_size);
1794
1795                 if (!delta_data) {
1796                         error("failed to unpack compressed delta "
1797                               "at offset %"PRIuMAX" from %s",
1798                               (uintmax_t)curpos, p->pack_name);
1799                         data = NULL;
1800                         free(external_base);
1801                         continue;
1802                 }
1803
1804                 data = patch_delta(base, base_size,
1805                                    delta_data, delta_size,
1806                                    &size);
1807
1808                 /*
1809                  * We could not apply the delta; warn the user, but keep going.
1810                  * Our failure will be noticed either in the next iteration of
1811                  * the loop, or if this is the final delta, in the caller when
1812                  * we return NULL. Those code paths will take care of making
1813                  * a more explicit warning and retrying with another copy of
1814                  * the object.
1815                  */
1816                 if (!data)
1817                         error("failed to apply delta");
1818
1819                 free(delta_data);
1820                 free(external_base);
1821         }
1822
1823         if (final_type)
1824                 *final_type = type;
1825         if (final_size)
1826                 *final_size = size;
1827
1828 out:
1829         unuse_pack(&w_curs);
1830
1831         if (delta_stack != small_delta_stack)
1832                 free(delta_stack);
1833
1834         return data;
1835 }
1836
1837 int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result)
1838 {
1839         const unsigned char *index_fanout = p->index_data;
1840         const unsigned char *index_lookup;
1841         const unsigned int hashsz = the_hash_algo->rawsz;
1842         int index_lookup_width;
1843
1844         if (!index_fanout)
1845                 BUG("bsearch_pack called without a valid pack-index");
1846
1847         index_lookup = index_fanout + 4 * 256;
1848         if (p->index_version == 1) {
1849                 index_lookup_width = hashsz + 4;
1850                 index_lookup += 4;
1851         } else {
1852                 index_lookup_width = hashsz;
1853                 index_fanout += 8;
1854                 index_lookup += 8;
1855         }
1856
1857         return bsearch_hash(oid->hash, (const uint32_t*)index_fanout,
1858                             index_lookup, index_lookup_width, result);
1859 }
1860
1861 const unsigned char *nth_packed_object_sha1(struct packed_git *p,
1862                                             uint32_t n)
1863 {
1864         const unsigned char *index = p->index_data;
1865         const unsigned int hashsz = the_hash_algo->rawsz;
1866         if (!index) {
1867                 if (open_pack_index(p))
1868                         return NULL;
1869                 index = p->index_data;
1870         }
1871         if (n >= p->num_objects)
1872                 return NULL;
1873         index += 4 * 256;
1874         if (p->index_version == 1) {
1875                 return index + (hashsz + 4) * n + 4;
1876         } else {
1877                 index += 8;
1878                 return index + hashsz * n;
1879         }
1880 }
1881
1882 const struct object_id *nth_packed_object_oid(struct object_id *oid,
1883                                               struct packed_git *p,
1884                                               uint32_t n)
1885 {
1886         const unsigned char *hash = nth_packed_object_sha1(p, n);
1887         if (!hash)
1888                 return NULL;
1889         hashcpy(oid->hash, hash);
1890         return oid;
1891 }
1892
1893 void check_pack_index_ptr(const struct packed_git *p, const void *vptr)
1894 {
1895         const unsigned char *ptr = vptr;
1896         const unsigned char *start = p->index_data;
1897         const unsigned char *end = start + p->index_size;
1898         if (ptr < start)
1899                 die(_("offset before start of pack index for %s (corrupt index?)"),
1900                     p->pack_name);
1901         /* No need to check for underflow; .idx files must be at least 8 bytes */
1902         if (ptr >= end - 8)
1903                 die(_("offset beyond end of pack index for %s (truncated index?)"),
1904                     p->pack_name);
1905 }
1906
1907 off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n)
1908 {
1909         const unsigned char *index = p->index_data;
1910         const unsigned int hashsz = the_hash_algo->rawsz;
1911         index += 4 * 256;
1912         if (p->index_version == 1) {
1913                 return ntohl(*((uint32_t *)(index + (hashsz + 4) * n)));
1914         } else {
1915                 uint32_t off;
1916                 index += 8 + p->num_objects * (hashsz + 4);
1917                 off = ntohl(*((uint32_t *)(index + 4 * n)));
1918                 if (!(off & 0x80000000))
1919                         return off;
1920                 index += p->num_objects * 4 + (off & 0x7fffffff) * 8;
1921                 check_pack_index_ptr(p, index);
1922                 return get_be64(index);
1923         }
1924 }
1925
1926 off_t find_pack_entry_one(const unsigned char *sha1,
1927                                   struct packed_git *p)
1928 {
1929         const unsigned char *index = p->index_data;
1930         struct object_id oid;
1931         uint32_t result;
1932
1933         if (!index) {
1934                 if (open_pack_index(p))
1935                         return 0;
1936         }
1937
1938         hashcpy(oid.hash, sha1);
1939         if (bsearch_pack(&oid, p, &result))
1940                 return nth_packed_object_offset(p, result);
1941         return 0;
1942 }
1943
1944 int is_pack_valid(struct packed_git *p)
1945 {
1946         /* An already open pack is known to be valid. */
1947         if (p->pack_fd != -1)
1948                 return 1;
1949
1950         /* If the pack has one window completely covering the
1951          * file size, the pack is known to be valid even if
1952          * the descriptor is not currently open.
1953          */
1954         if (p->windows) {
1955                 struct pack_window *w = p->windows;
1956
1957                 if (!w->offset && w->len == p->pack_size)
1958                         return 1;
1959         }
1960
1961         /* Force the pack to open to prove its valid. */
1962         return !open_packed_git(p);
1963 }
1964
1965 struct packed_git *find_sha1_pack(const unsigned char *sha1,
1966                                   struct packed_git *packs)
1967 {
1968         struct packed_git *p;
1969
1970         for (p = packs; p; p = p->next) {
1971                 if (find_pack_entry_one(sha1, p))
1972                         return p;
1973         }
1974         return NULL;
1975
1976 }
1977
1978 static int fill_pack_entry(const struct object_id *oid,
1979                            struct pack_entry *e,
1980                            struct packed_git *p)
1981 {
1982         off_t offset;
1983
1984         if (p->num_bad_objects) {
1985                 unsigned i;
1986                 for (i = 0; i < p->num_bad_objects; i++)
1987                         if (hasheq(oid->hash,
1988                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
1989                                 return 0;
1990         }
1991
1992         offset = find_pack_entry_one(oid->hash, p);
1993         if (!offset)
1994                 return 0;
1995
1996         /*
1997          * We are about to tell the caller where they can locate the
1998          * requested object.  We better make sure the packfile is
1999          * still here and can be accessed before supplying that
2000          * answer, as it may have been deleted since the index was
2001          * loaded!
2002          */
2003         if (!is_pack_valid(p))
2004                 return 0;
2005         e->offset = offset;
2006         e->p = p;
2007         return 1;
2008 }
2009
2010 int find_pack_entry(struct repository *r, const struct object_id *oid, struct pack_entry *e)
2011 {
2012         struct list_head *pos;
2013         struct multi_pack_index *m;
2014
2015         prepare_packed_git(r);
2016         if (!r->objects->packed_git && !r->objects->multi_pack_index)
2017                 return 0;
2018
2019         for (m = r->objects->multi_pack_index; m; m = m->next) {
2020                 if (fill_midx_entry(r, oid, e, m))
2021                         return 1;
2022         }
2023
2024         list_for_each(pos, &r->objects->packed_git_mru) {
2025                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
2026                 if (!p->multi_pack_index && fill_pack_entry(oid, e, p)) {
2027                         list_move(&p->mru, &r->objects->packed_git_mru);
2028                         return 1;
2029                 }
2030         }
2031         return 0;
2032 }
2033
2034 int has_object_pack(const struct object_id *oid)
2035 {
2036         struct pack_entry e;
2037         return find_pack_entry(the_repository, oid, &e);
2038 }
2039
2040 int has_pack_index(const unsigned char *sha1)
2041 {
2042         struct stat st;
2043         if (stat(sha1_pack_index_name(sha1), &st))
2044                 return 0;
2045         return 1;
2046 }
2047
2048 int for_each_object_in_pack(struct packed_git *p,
2049                             each_packed_object_fn cb, void *data,
2050                             enum for_each_object_flags flags)
2051 {
2052         uint32_t i;
2053         int r = 0;
2054
2055         if (flags & FOR_EACH_OBJECT_PACK_ORDER) {
2056                 if (load_pack_revindex(p))
2057                         return -1;
2058         }
2059
2060         for (i = 0; i < p->num_objects; i++) {
2061                 uint32_t pos;
2062                 struct object_id oid;
2063
2064                 if (flags & FOR_EACH_OBJECT_PACK_ORDER)
2065                         pos = p->revindex[i].nr;
2066                 else
2067                         pos = i;
2068
2069                 if (!nth_packed_object_oid(&oid, p, pos))
2070                         return error("unable to get sha1 of object %u in %s",
2071                                      pos, p->pack_name);
2072
2073                 r = cb(&oid, p, pos, data);
2074                 if (r)
2075                         break;
2076         }
2077         return r;
2078 }
2079
2080 int for_each_packed_object(each_packed_object_fn cb, void *data,
2081                            enum for_each_object_flags flags)
2082 {
2083         struct packed_git *p;
2084         int r = 0;
2085         int pack_errors = 0;
2086
2087         prepare_packed_git(the_repository);
2088         for (p = get_all_packs(the_repository); p; p = p->next) {
2089                 if ((flags & FOR_EACH_OBJECT_LOCAL_ONLY) && !p->pack_local)
2090                         continue;
2091                 if ((flags & FOR_EACH_OBJECT_PROMISOR_ONLY) &&
2092                     !p->pack_promisor)
2093                         continue;
2094                 if (open_pack_index(p)) {
2095                         pack_errors = 1;
2096                         continue;
2097                 }
2098                 r = for_each_object_in_pack(p, cb, data, flags);
2099                 if (r)
2100                         break;
2101         }
2102         return r ? r : pack_errors;
2103 }
2104
2105 static int add_promisor_object(const struct object_id *oid,
2106                                struct packed_git *pack,
2107                                uint32_t pos,
2108                                void *set_)
2109 {
2110         struct oidset *set = set_;
2111         struct object *obj = parse_object(the_repository, oid);
2112         if (!obj)
2113                 return 1;
2114
2115         oidset_insert(set, oid);
2116
2117         /*
2118          * If this is a tree, commit, or tag, the objects it refers
2119          * to are also promisor objects. (Blobs refer to no objects->)
2120          */
2121         if (obj->type == OBJ_TREE) {
2122                 struct tree *tree = (struct tree *)obj;
2123                 struct tree_desc desc;
2124                 struct name_entry entry;
2125                 if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
2126                         /*
2127                          * Error messages are given when packs are
2128                          * verified, so do not print any here.
2129                          */
2130                         return 0;
2131                 while (tree_entry_gently(&desc, &entry))
2132                         oidset_insert(set, &entry.oid);
2133         } else if (obj->type == OBJ_COMMIT) {
2134                 struct commit *commit = (struct commit *) obj;
2135                 struct commit_list *parents = commit->parents;
2136
2137                 oidset_insert(set, get_commit_tree_oid(commit));
2138                 for (; parents; parents = parents->next)
2139                         oidset_insert(set, &parents->item->object.oid);
2140         } else if (obj->type == OBJ_TAG) {
2141                 struct tag *tag = (struct tag *) obj;
2142                 oidset_insert(set, &tag->tagged->oid);
2143         }
2144         return 0;
2145 }
2146
2147 int is_promisor_object(const struct object_id *oid)
2148 {
2149         static struct oidset promisor_objects;
2150         static int promisor_objects_prepared;
2151
2152         if (!promisor_objects_prepared) {
2153                 if (repository_format_partial_clone) {
2154                         for_each_packed_object(add_promisor_object,
2155                                                &promisor_objects,
2156                                                FOR_EACH_OBJECT_PROMISOR_ONLY);
2157                 }
2158                 promisor_objects_prepared = 1;
2159         }
2160         return oidset_contains(&promisor_objects, oid);
2161 }