Merge branch 'ds/multi-pack-verify'
[git] / midx.c
1 #include "cache.h"
2 #include "config.h"
3 #include "csum-file.h"
4 #include "dir.h"
5 #include "lockfile.h"
6 #include "packfile.h"
7 #include "object-store.h"
8 #include "sha1-lookup.h"
9 #include "midx.h"
10 #include "progress.h"
11 #include "trace2.h"
12 #include "run-command.h"
13
14 #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */
15 #define MIDX_VERSION 1
16 #define MIDX_BYTE_FILE_VERSION 4
17 #define MIDX_BYTE_HASH_VERSION 5
18 #define MIDX_BYTE_NUM_CHUNKS 6
19 #define MIDX_BYTE_NUM_PACKS 8
20 #define MIDX_HASH_VERSION 1
21 #define MIDX_HEADER_SIZE 12
22 #define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + the_hash_algo->rawsz)
23
24 #define MIDX_MAX_CHUNKS 5
25 #define MIDX_CHUNK_ALIGNMENT 4
26 #define MIDX_CHUNKID_PACKNAMES 0x504e414d /* "PNAM" */
27 #define MIDX_CHUNKID_OIDFANOUT 0x4f494446 /* "OIDF" */
28 #define MIDX_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */
29 #define MIDX_CHUNKID_OBJECTOFFSETS 0x4f4f4646 /* "OOFF" */
30 #define MIDX_CHUNKID_LARGEOFFSETS 0x4c4f4646 /* "LOFF" */
31 #define MIDX_CHUNKLOOKUP_WIDTH (sizeof(uint32_t) + sizeof(uint64_t))
32 #define MIDX_CHUNK_FANOUT_SIZE (sizeof(uint32_t) * 256)
33 #define MIDX_CHUNK_OFFSET_WIDTH (2 * sizeof(uint32_t))
34 #define MIDX_CHUNK_LARGE_OFFSET_WIDTH (sizeof(uint64_t))
35 #define MIDX_LARGE_OFFSET_NEEDED 0x80000000
36
37 #define PACK_EXPIRED UINT_MAX
38
39 static char *get_midx_filename(const char *object_dir)
40 {
41         return xstrfmt("%s/pack/multi-pack-index", object_dir);
42 }
43
44 struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
45 {
46         struct multi_pack_index *m = NULL;
47         int fd;
48         struct stat st;
49         size_t midx_size;
50         void *midx_map = NULL;
51         uint32_t hash_version;
52         char *midx_name = get_midx_filename(object_dir);
53         uint32_t i;
54         const char *cur_pack_name;
55
56         fd = git_open(midx_name);
57
58         if (fd < 0)
59                 goto cleanup_fail;
60         if (fstat(fd, &st)) {
61                 error_errno(_("failed to read %s"), midx_name);
62                 goto cleanup_fail;
63         }
64
65         midx_size = xsize_t(st.st_size);
66
67         if (midx_size < MIDX_MIN_SIZE) {
68                 error(_("multi-pack-index file %s is too small"), midx_name);
69                 goto cleanup_fail;
70         }
71
72         FREE_AND_NULL(midx_name);
73
74         midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
75         close(fd);
76
77         FLEX_ALLOC_STR(m, object_dir, object_dir);
78         m->data = midx_map;
79         m->data_len = midx_size;
80         m->local = local;
81
82         m->signature = get_be32(m->data);
83         if (m->signature != MIDX_SIGNATURE)
84                 die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
85                       m->signature, MIDX_SIGNATURE);
86
87         m->version = m->data[MIDX_BYTE_FILE_VERSION];
88         if (m->version != MIDX_VERSION)
89                 die(_("multi-pack-index version %d not recognized"),
90                       m->version);
91
92         hash_version = m->data[MIDX_BYTE_HASH_VERSION];
93         if (hash_version != MIDX_HASH_VERSION)
94                 die(_("hash version %u does not match"), hash_version);
95         m->hash_len = the_hash_algo->rawsz;
96
97         m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
98
99         m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
100
101         for (i = 0; i < m->num_chunks; i++) {
102                 uint32_t chunk_id = get_be32(m->data + MIDX_HEADER_SIZE +
103                                              MIDX_CHUNKLOOKUP_WIDTH * i);
104                 uint64_t chunk_offset = get_be64(m->data + MIDX_HEADER_SIZE + 4 +
105                                                  MIDX_CHUNKLOOKUP_WIDTH * i);
106
107                 if (chunk_offset >= m->data_len)
108                         die(_("invalid chunk offset (too large)"));
109
110                 switch (chunk_id) {
111                         case MIDX_CHUNKID_PACKNAMES:
112                                 m->chunk_pack_names = m->data + chunk_offset;
113                                 break;
114
115                         case MIDX_CHUNKID_OIDFANOUT:
116                                 m->chunk_oid_fanout = (uint32_t *)(m->data + chunk_offset);
117                                 break;
118
119                         case MIDX_CHUNKID_OIDLOOKUP:
120                                 m->chunk_oid_lookup = m->data + chunk_offset;
121                                 break;
122
123                         case MIDX_CHUNKID_OBJECTOFFSETS:
124                                 m->chunk_object_offsets = m->data + chunk_offset;
125                                 break;
126
127                         case MIDX_CHUNKID_LARGEOFFSETS:
128                                 m->chunk_large_offsets = m->data + chunk_offset;
129                                 break;
130
131                         case 0:
132                                 die(_("terminating multi-pack-index chunk id appears earlier than expected"));
133                                 break;
134
135                         default:
136                                 /*
137                                  * Do nothing on unrecognized chunks, allowing future
138                                  * extensions to add optional chunks.
139                                  */
140                                 break;
141                 }
142         }
143
144         if (!m->chunk_pack_names)
145                 die(_("multi-pack-index missing required pack-name chunk"));
146         if (!m->chunk_oid_fanout)
147                 die(_("multi-pack-index missing required OID fanout chunk"));
148         if (!m->chunk_oid_lookup)
149                 die(_("multi-pack-index missing required OID lookup chunk"));
150         if (!m->chunk_object_offsets)
151                 die(_("multi-pack-index missing required object offsets chunk"));
152
153         m->num_objects = ntohl(m->chunk_oid_fanout[255]);
154
155         m->pack_names = xcalloc(m->num_packs, sizeof(*m->pack_names));
156         m->packs = xcalloc(m->num_packs, sizeof(*m->packs));
157
158         cur_pack_name = (const char *)m->chunk_pack_names;
159         for (i = 0; i < m->num_packs; i++) {
160                 m->pack_names[i] = cur_pack_name;
161
162                 cur_pack_name += strlen(cur_pack_name) + 1;
163
164                 if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0)
165                         die(_("multi-pack-index pack names out of order: '%s' before '%s'"),
166                               m->pack_names[i - 1],
167                               m->pack_names[i]);
168         }
169
170         trace2_data_intmax("midx", the_repository, "load/num_packs", m->num_packs);
171         trace2_data_intmax("midx", the_repository, "load/num_objects", m->num_objects);
172
173         return m;
174
175 cleanup_fail:
176         free(m);
177         free(midx_name);
178         if (midx_map)
179                 munmap(midx_map, midx_size);
180         if (0 <= fd)
181                 close(fd);
182         return NULL;
183 }
184
185 void close_midx(struct multi_pack_index *m)
186 {
187         uint32_t i;
188
189         if (!m)
190                 return;
191
192         munmap((unsigned char *)m->data, m->data_len);
193
194         for (i = 0; i < m->num_packs; i++) {
195                 if (m->packs[i])
196                         m->packs[i]->multi_pack_index = 0;
197         }
198         FREE_AND_NULL(m->packs);
199         FREE_AND_NULL(m->pack_names);
200 }
201
202 int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id)
203 {
204         struct strbuf pack_name = STRBUF_INIT;
205         struct packed_git *p;
206
207         if (pack_int_id >= m->num_packs)
208                 die(_("bad pack-int-id: %u (%u total packs)"),
209                     pack_int_id, m->num_packs);
210
211         if (m->packs[pack_int_id])
212                 return 0;
213
214         strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
215                     m->pack_names[pack_int_id]);
216
217         p = add_packed_git(pack_name.buf, pack_name.len, m->local);
218         strbuf_release(&pack_name);
219
220         if (!p)
221                 return 1;
222
223         p->multi_pack_index = 1;
224         m->packs[pack_int_id] = p;
225         install_packed_git(r, p);
226         list_add_tail(&p->mru, &r->objects->packed_git_mru);
227
228         return 0;
229 }
230
231 int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
232 {
233         return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
234                             the_hash_algo->rawsz, result);
235 }
236
237 struct object_id *nth_midxed_object_oid(struct object_id *oid,
238                                         struct multi_pack_index *m,
239                                         uint32_t n)
240 {
241         if (n >= m->num_objects)
242                 return NULL;
243
244         hashcpy(oid->hash, m->chunk_oid_lookup + m->hash_len * n);
245         return oid;
246 }
247
248 static off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
249 {
250         const unsigned char *offset_data;
251         uint32_t offset32;
252
253         offset_data = m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH;
254         offset32 = get_be32(offset_data + sizeof(uint32_t));
255
256         if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
257                 if (sizeof(off_t) < sizeof(uint64_t))
258                         die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
259
260                 offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
261                 return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
262         }
263
264         return offset32;
265 }
266
267 static uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
268 {
269         return get_be32(m->chunk_object_offsets + pos * MIDX_CHUNK_OFFSET_WIDTH);
270 }
271
272 static int nth_midxed_pack_entry(struct repository *r,
273                                  struct multi_pack_index *m,
274                                  struct pack_entry *e,
275                                  uint32_t pos)
276 {
277         uint32_t pack_int_id;
278         struct packed_git *p;
279
280         if (pos >= m->num_objects)
281                 return 0;
282
283         pack_int_id = nth_midxed_pack_int_id(m, pos);
284
285         if (prepare_midx_pack(r, m, pack_int_id))
286                 die(_("error preparing packfile from multi-pack-index"));
287         p = m->packs[pack_int_id];
288
289         /*
290         * We are about to tell the caller where they can locate the
291         * requested object.  We better make sure the packfile is
292         * still here and can be accessed before supplying that
293         * answer, as it may have been deleted since the MIDX was
294         * loaded!
295         */
296         if (!is_pack_valid(p))
297                 return 0;
298
299         if (p->num_bad_objects) {
300                 uint32_t i;
301                 struct object_id oid;
302                 nth_midxed_object_oid(&oid, m, pos);
303                 for (i = 0; i < p->num_bad_objects; i++)
304                         if (hasheq(oid.hash,
305                                    p->bad_object_sha1 + the_hash_algo->rawsz * i))
306                                 return 0;
307         }
308
309         e->offset = nth_midxed_offset(m, pos);
310         e->p = p;
311
312         return 1;
313 }
314
315 int fill_midx_entry(struct repository * r,
316                     const struct object_id *oid,
317                     struct pack_entry *e,
318                     struct multi_pack_index *m)
319 {
320         uint32_t pos;
321
322         if (!bsearch_midx(oid, m, &pos))
323                 return 0;
324
325         return nth_midxed_pack_entry(r, m, e, pos);
326 }
327
328 /* Match "foo.idx" against either "foo.pack" _or_ "foo.idx". */
329 static int cmp_idx_or_pack_name(const char *idx_or_pack_name,
330                                 const char *idx_name)
331 {
332         /* Skip past any initial matching prefix. */
333         while (*idx_name && *idx_name == *idx_or_pack_name) {
334                 idx_name++;
335                 idx_or_pack_name++;
336         }
337
338         /*
339          * If we didn't match completely, we may have matched "pack-1234." and
340          * be left with "idx" and "pack" respectively, which is also OK. We do
341          * not have to check for "idx" and "idx", because that would have been
342          * a complete match (and in that case these strcmps will be false, but
343          * we'll correctly return 0 from the final strcmp() below.
344          *
345          * Technically this matches "fooidx" and "foopack", but we'd never have
346          * such names in the first place.
347          */
348         if (!strcmp(idx_name, "idx") && !strcmp(idx_or_pack_name, "pack"))
349                 return 0;
350
351         /*
352          * This not only checks for a complete match, but also orders based on
353          * the first non-identical character, which means our ordering will
354          * match a raw strcmp(). That makes it OK to use this to binary search
355          * a naively-sorted list.
356          */
357         return strcmp(idx_or_pack_name, idx_name);
358 }
359
360 int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name)
361 {
362         uint32_t first = 0, last = m->num_packs;
363
364         while (first < last) {
365                 uint32_t mid = first + (last - first) / 2;
366                 const char *current;
367                 int cmp;
368
369                 current = m->pack_names[mid];
370                 cmp = cmp_idx_or_pack_name(idx_or_pack_name, current);
371                 if (!cmp)
372                         return 1;
373                 if (cmp > 0) {
374                         first = mid + 1;
375                         continue;
376                 }
377                 last = mid;
378         }
379
380         return 0;
381 }
382
383 int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
384 {
385         struct multi_pack_index *m;
386         struct multi_pack_index *m_search;
387         int config_value;
388         static int env_value = -1;
389
390         if (env_value < 0)
391                 env_value = git_env_bool(GIT_TEST_MULTI_PACK_INDEX, 0);
392
393         if (!env_value &&
394             (repo_config_get_bool(r, "core.multipackindex", &config_value) ||
395             !config_value))
396                 return 0;
397
398         for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
399                 if (!strcmp(object_dir, m_search->object_dir))
400                         return 1;
401
402         m = load_multi_pack_index(object_dir, local);
403
404         if (m) {
405                 m->next = r->objects->multi_pack_index;
406                 r->objects->multi_pack_index = m;
407                 return 1;
408         }
409
410         return 0;
411 }
412
413 static size_t write_midx_header(struct hashfile *f,
414                                 unsigned char num_chunks,
415                                 uint32_t num_packs)
416 {
417         unsigned char byte_values[4];
418
419         hashwrite_be32(f, MIDX_SIGNATURE);
420         byte_values[0] = MIDX_VERSION;
421         byte_values[1] = MIDX_HASH_VERSION;
422         byte_values[2] = num_chunks;
423         byte_values[3] = 0; /* unused */
424         hashwrite(f, byte_values, sizeof(byte_values));
425         hashwrite_be32(f, num_packs);
426
427         return MIDX_HEADER_SIZE;
428 }
429
430 struct pack_info {
431         uint32_t orig_pack_int_id;
432         char *pack_name;
433         struct packed_git *p;
434         unsigned expired : 1;
435 };
436
437 static int pack_info_compare(const void *_a, const void *_b)
438 {
439         struct pack_info *a = (struct pack_info *)_a;
440         struct pack_info *b = (struct pack_info *)_b;
441         return strcmp(a->pack_name, b->pack_name);
442 }
443
444 struct pack_list {
445         struct pack_info *info;
446         uint32_t nr;
447         uint32_t alloc;
448         struct multi_pack_index *m;
449         struct progress *progress;
450         unsigned pack_paths_checked;
451 };
452
453 static void add_pack_to_midx(const char *full_path, size_t full_path_len,
454                              const char *file_name, void *data)
455 {
456         struct pack_list *packs = (struct pack_list *)data;
457
458         if (ends_with(file_name, ".idx")) {
459                 display_progress(packs->progress, ++packs->pack_paths_checked);
460                 if (packs->m && midx_contains_pack(packs->m, file_name))
461                         return;
462
463                 ALLOC_GROW(packs->info, packs->nr + 1, packs->alloc);
464
465                 packs->info[packs->nr].p = add_packed_git(full_path,
466                                                           full_path_len,
467                                                           0);
468
469                 if (!packs->info[packs->nr].p) {
470                         warning(_("failed to add packfile '%s'"),
471                                 full_path);
472                         return;
473                 }
474
475                 if (open_pack_index(packs->info[packs->nr].p)) {
476                         warning(_("failed to open pack-index '%s'"),
477                                 full_path);
478                         close_pack(packs->info[packs->nr].p);
479                         FREE_AND_NULL(packs->info[packs->nr].p);
480                         return;
481                 }
482
483                 packs->info[packs->nr].pack_name = xstrdup(file_name);
484                 packs->info[packs->nr].orig_pack_int_id = packs->nr;
485                 packs->info[packs->nr].expired = 0;
486                 packs->nr++;
487         }
488 }
489
490 struct pack_midx_entry {
491         struct object_id oid;
492         uint32_t pack_int_id;
493         time_t pack_mtime;
494         uint64_t offset;
495 };
496
497 static int midx_oid_compare(const void *_a, const void *_b)
498 {
499         const struct pack_midx_entry *a = (const struct pack_midx_entry *)_a;
500         const struct pack_midx_entry *b = (const struct pack_midx_entry *)_b;
501         int cmp = oidcmp(&a->oid, &b->oid);
502
503         if (cmp)
504                 return cmp;
505
506         if (a->pack_mtime > b->pack_mtime)
507                 return -1;
508         else if (a->pack_mtime < b->pack_mtime)
509                 return 1;
510
511         return a->pack_int_id - b->pack_int_id;
512 }
513
514 static int nth_midxed_pack_midx_entry(struct multi_pack_index *m,
515                                       struct pack_midx_entry *e,
516                                       uint32_t pos)
517 {
518         if (pos >= m->num_objects)
519                 return 1;
520
521         nth_midxed_object_oid(&e->oid, m, pos);
522         e->pack_int_id = nth_midxed_pack_int_id(m, pos);
523         e->offset = nth_midxed_offset(m, pos);
524
525         /* consider objects in midx to be from "old" packs */
526         e->pack_mtime = 0;
527         return 0;
528 }
529
530 static void fill_pack_entry(uint32_t pack_int_id,
531                             struct packed_git *p,
532                             uint32_t cur_object,
533                             struct pack_midx_entry *entry)
534 {
535         if (nth_packed_object_id(&entry->oid, p, cur_object) < 0)
536                 die(_("failed to locate object %d in packfile"), cur_object);
537
538         entry->pack_int_id = pack_int_id;
539         entry->pack_mtime = p->mtime;
540
541         entry->offset = nth_packed_object_offset(p, cur_object);
542 }
543
544 /*
545  * It is possible to artificially get into a state where there are many
546  * duplicate copies of objects. That can create high memory pressure if
547  * we are to create a list of all objects before de-duplication. To reduce
548  * this memory pressure without a significant performance drop, automatically
549  * group objects by the first byte of their object id. Use the IDX fanout
550  * tables to group the data, copy to a local array, then sort.
551  *
552  * Copy only the de-duplicated entries (selected by most-recent modified time
553  * of a packfile containing the object).
554  */
555 static struct pack_midx_entry *get_sorted_entries(struct multi_pack_index *m,
556                                                   struct pack_info *info,
557                                                   uint32_t nr_packs,
558                                                   uint32_t *nr_objects)
559 {
560         uint32_t cur_fanout, cur_pack, cur_object;
561         uint32_t alloc_fanout, alloc_objects, total_objects = 0;
562         struct pack_midx_entry *entries_by_fanout = NULL;
563         struct pack_midx_entry *deduplicated_entries = NULL;
564         uint32_t start_pack = m ? m->num_packs : 0;
565
566         for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++)
567                 total_objects += info[cur_pack].p->num_objects;
568
569         /*
570          * As we de-duplicate by fanout value, we expect the fanout
571          * slices to be evenly distributed, with some noise. Hence,
572          * allocate slightly more than one 256th.
573          */
574         alloc_objects = alloc_fanout = total_objects > 3200 ? total_objects / 200 : 16;
575
576         ALLOC_ARRAY(entries_by_fanout, alloc_fanout);
577         ALLOC_ARRAY(deduplicated_entries, alloc_objects);
578         *nr_objects = 0;
579
580         for (cur_fanout = 0; cur_fanout < 256; cur_fanout++) {
581                 uint32_t nr_fanout = 0;
582
583                 if (m) {
584                         uint32_t start = 0, end;
585
586                         if (cur_fanout)
587                                 start = ntohl(m->chunk_oid_fanout[cur_fanout - 1]);
588                         end = ntohl(m->chunk_oid_fanout[cur_fanout]);
589
590                         for (cur_object = start; cur_object < end; cur_object++) {
591                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
592                                 nth_midxed_pack_midx_entry(m,
593                                                            &entries_by_fanout[nr_fanout],
594                                                            cur_object);
595                                 nr_fanout++;
596                         }
597                 }
598
599                 for (cur_pack = start_pack; cur_pack < nr_packs; cur_pack++) {
600                         uint32_t start = 0, end;
601
602                         if (cur_fanout)
603                                 start = get_pack_fanout(info[cur_pack].p, cur_fanout - 1);
604                         end = get_pack_fanout(info[cur_pack].p, cur_fanout);
605
606                         for (cur_object = start; cur_object < end; cur_object++) {
607                                 ALLOC_GROW(entries_by_fanout, nr_fanout + 1, alloc_fanout);
608                                 fill_pack_entry(cur_pack, info[cur_pack].p, cur_object, &entries_by_fanout[nr_fanout]);
609                                 nr_fanout++;
610                         }
611                 }
612
613                 QSORT(entries_by_fanout, nr_fanout, midx_oid_compare);
614
615                 /*
616                  * The batch is now sorted by OID and then mtime (descending).
617                  * Take only the first duplicate.
618                  */
619                 for (cur_object = 0; cur_object < nr_fanout; cur_object++) {
620                         if (cur_object && oideq(&entries_by_fanout[cur_object - 1].oid,
621                                                 &entries_by_fanout[cur_object].oid))
622                                 continue;
623
624                         ALLOC_GROW(deduplicated_entries, *nr_objects + 1, alloc_objects);
625                         memcpy(&deduplicated_entries[*nr_objects],
626                                &entries_by_fanout[cur_object],
627                                sizeof(struct pack_midx_entry));
628                         (*nr_objects)++;
629                 }
630         }
631
632         free(entries_by_fanout);
633         return deduplicated_entries;
634 }
635
636 static size_t write_midx_pack_names(struct hashfile *f,
637                                     struct pack_info *info,
638                                     uint32_t num_packs)
639 {
640         uint32_t i;
641         unsigned char padding[MIDX_CHUNK_ALIGNMENT];
642         size_t written = 0;
643
644         for (i = 0; i < num_packs; i++) {
645                 size_t writelen;
646
647                 if (info[i].expired)
648                         continue;
649
650                 if (i && strcmp(info[i].pack_name, info[i - 1].pack_name) <= 0)
651                         BUG("incorrect pack-file order: %s before %s",
652                             info[i - 1].pack_name,
653                             info[i].pack_name);
654
655                 writelen = strlen(info[i].pack_name) + 1;
656                 hashwrite(f, info[i].pack_name, writelen);
657                 written += writelen;
658         }
659
660         /* add padding to be aligned */
661         i = MIDX_CHUNK_ALIGNMENT - (written % MIDX_CHUNK_ALIGNMENT);
662         if (i < MIDX_CHUNK_ALIGNMENT) {
663                 memset(padding, 0, sizeof(padding));
664                 hashwrite(f, padding, i);
665                 written += i;
666         }
667
668         return written;
669 }
670
671 static size_t write_midx_oid_fanout(struct hashfile *f,
672                                     struct pack_midx_entry *objects,
673                                     uint32_t nr_objects)
674 {
675         struct pack_midx_entry *list = objects;
676         struct pack_midx_entry *last = objects + nr_objects;
677         uint32_t count = 0;
678         uint32_t i;
679
680         /*
681         * Write the first-level table (the list is sorted,
682         * but we use a 256-entry lookup to be able to avoid
683         * having to do eight extra binary search iterations).
684         */
685         for (i = 0; i < 256; i++) {
686                 struct pack_midx_entry *next = list;
687
688                 while (next < last && next->oid.hash[0] == i) {
689                         count++;
690                         next++;
691                 }
692
693                 hashwrite_be32(f, count);
694                 list = next;
695         }
696
697         return MIDX_CHUNK_FANOUT_SIZE;
698 }
699
700 static size_t write_midx_oid_lookup(struct hashfile *f, unsigned char hash_len,
701                                     struct pack_midx_entry *objects,
702                                     uint32_t nr_objects)
703 {
704         struct pack_midx_entry *list = objects;
705         uint32_t i;
706         size_t written = 0;
707
708         for (i = 0; i < nr_objects; i++) {
709                 struct pack_midx_entry *obj = list++;
710
711                 if (i < nr_objects - 1) {
712                         struct pack_midx_entry *next = list;
713                         if (oidcmp(&obj->oid, &next->oid) >= 0)
714                                 BUG("OIDs not in order: %s >= %s",
715                                     oid_to_hex(&obj->oid),
716                                     oid_to_hex(&next->oid));
717                 }
718
719                 hashwrite(f, obj->oid.hash, (int)hash_len);
720                 written += hash_len;
721         }
722
723         return written;
724 }
725
726 static size_t write_midx_object_offsets(struct hashfile *f, int large_offset_needed,
727                                         uint32_t *perm,
728                                         struct pack_midx_entry *objects, uint32_t nr_objects)
729 {
730         struct pack_midx_entry *list = objects;
731         uint32_t i, nr_large_offset = 0;
732         size_t written = 0;
733
734         for (i = 0; i < nr_objects; i++) {
735                 struct pack_midx_entry *obj = list++;
736
737                 if (perm[obj->pack_int_id] == PACK_EXPIRED)
738                         BUG("object %s is in an expired pack with int-id %d",
739                             oid_to_hex(&obj->oid),
740                             obj->pack_int_id);
741
742                 hashwrite_be32(f, perm[obj->pack_int_id]);
743
744                 if (large_offset_needed && obj->offset >> 31)
745                         hashwrite_be32(f, MIDX_LARGE_OFFSET_NEEDED | nr_large_offset++);
746                 else if (!large_offset_needed && obj->offset >> 32)
747                         BUG("object %s requires a large offset (%"PRIx64") but the MIDX is not writing large offsets!",
748                             oid_to_hex(&obj->oid),
749                             obj->offset);
750                 else
751                         hashwrite_be32(f, (uint32_t)obj->offset);
752
753                 written += MIDX_CHUNK_OFFSET_WIDTH;
754         }
755
756         return written;
757 }
758
759 static size_t write_midx_large_offsets(struct hashfile *f, uint32_t nr_large_offset,
760                                        struct pack_midx_entry *objects, uint32_t nr_objects)
761 {
762         struct pack_midx_entry *list = objects, *end = objects + nr_objects;
763         size_t written = 0;
764
765         while (nr_large_offset) {
766                 struct pack_midx_entry *obj;
767                 uint64_t offset;
768
769                 if (list >= end)
770                         BUG("too many large-offset objects");
771
772                 obj = list++;
773                 offset = obj->offset;
774
775                 if (!(offset >> 31))
776                         continue;
777
778                 hashwrite_be32(f, offset >> 32);
779                 hashwrite_be32(f, offset & 0xffffffffUL);
780                 written += 2 * sizeof(uint32_t);
781
782                 nr_large_offset--;
783         }
784
785         return written;
786 }
787
788 static int write_midx_internal(const char *object_dir, struct multi_pack_index *m,
789                                struct string_list *packs_to_drop, unsigned flags)
790 {
791         unsigned char cur_chunk, num_chunks = 0;
792         char *midx_name;
793         uint32_t i;
794         struct hashfile *f = NULL;
795         struct lock_file lk;
796         struct pack_list packs;
797         uint32_t *pack_perm = NULL;
798         uint64_t written = 0;
799         uint32_t chunk_ids[MIDX_MAX_CHUNKS + 1];
800         uint64_t chunk_offsets[MIDX_MAX_CHUNKS + 1];
801         uint32_t nr_entries, num_large_offsets = 0;
802         struct pack_midx_entry *entries = NULL;
803         struct progress *progress = NULL;
804         int large_offsets_needed = 0;
805         int pack_name_concat_len = 0;
806         int dropped_packs = 0;
807         int result = 0;
808
809         midx_name = get_midx_filename(object_dir);
810         if (safe_create_leading_directories(midx_name)) {
811                 UNLEAK(midx_name);
812                 die_errno(_("unable to create leading directories of %s"),
813                           midx_name);
814         }
815
816         if (m)
817                 packs.m = m;
818         else
819                 packs.m = load_multi_pack_index(object_dir, 1);
820
821         packs.nr = 0;
822         packs.alloc = packs.m ? packs.m->num_packs : 16;
823         packs.info = NULL;
824         ALLOC_ARRAY(packs.info, packs.alloc);
825
826         if (packs.m) {
827                 for (i = 0; i < packs.m->num_packs; i++) {
828                         ALLOC_GROW(packs.info, packs.nr + 1, packs.alloc);
829
830                         packs.info[packs.nr].orig_pack_int_id = i;
831                         packs.info[packs.nr].pack_name = xstrdup(packs.m->pack_names[i]);
832                         packs.info[packs.nr].p = NULL;
833                         packs.info[packs.nr].expired = 0;
834                         packs.nr++;
835                 }
836         }
837
838         packs.pack_paths_checked = 0;
839         if (flags & MIDX_PROGRESS)
840                 packs.progress = start_progress(_("Adding packfiles to multi-pack-index"), 0);
841         else
842                 packs.progress = NULL;
843
844         for_each_file_in_pack_dir(object_dir, add_pack_to_midx, &packs);
845         stop_progress(&packs.progress);
846
847         if (packs.m && packs.nr == packs.m->num_packs && !packs_to_drop)
848                 goto cleanup;
849
850         entries = get_sorted_entries(packs.m, packs.info, packs.nr, &nr_entries);
851
852         for (i = 0; i < nr_entries; i++) {
853                 if (entries[i].offset > 0x7fffffff)
854                         num_large_offsets++;
855                 if (entries[i].offset > 0xffffffff)
856                         large_offsets_needed = 1;
857         }
858
859         QSORT(packs.info, packs.nr, pack_info_compare);
860
861         if (packs_to_drop && packs_to_drop->nr) {
862                 int drop_index = 0;
863                 int missing_drops = 0;
864
865                 for (i = 0; i < packs.nr && drop_index < packs_to_drop->nr; i++) {
866                         int cmp = strcmp(packs.info[i].pack_name,
867                                          packs_to_drop->items[drop_index].string);
868
869                         if (!cmp) {
870                                 drop_index++;
871                                 packs.info[i].expired = 1;
872                         } else if (cmp > 0) {
873                                 error(_("did not see pack-file %s to drop"),
874                                       packs_to_drop->items[drop_index].string);
875                                 drop_index++;
876                                 missing_drops++;
877                                 i--;
878                         } else {
879                                 packs.info[i].expired = 0;
880                         }
881                 }
882
883                 if (missing_drops) {
884                         result = 1;
885                         goto cleanup;
886                 }
887         }
888
889         /*
890          * pack_perm stores a permutation between pack-int-ids from the
891          * previous multi-pack-index to the new one we are writing:
892          *
893          * pack_perm[old_id] = new_id
894          */
895         ALLOC_ARRAY(pack_perm, packs.nr);
896         for (i = 0; i < packs.nr; i++) {
897                 if (packs.info[i].expired) {
898                         dropped_packs++;
899                         pack_perm[packs.info[i].orig_pack_int_id] = PACK_EXPIRED;
900                 } else {
901                         pack_perm[packs.info[i].orig_pack_int_id] = i - dropped_packs;
902                 }
903         }
904
905         for (i = 0; i < packs.nr; i++) {
906                 if (!packs.info[i].expired)
907                         pack_name_concat_len += strlen(packs.info[i].pack_name) + 1;
908         }
909
910         if (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT)
911                 pack_name_concat_len += MIDX_CHUNK_ALIGNMENT -
912                                         (pack_name_concat_len % MIDX_CHUNK_ALIGNMENT);
913
914         hold_lock_file_for_update(&lk, midx_name, LOCK_DIE_ON_ERROR);
915         f = hashfd(lk.tempfile->fd, lk.tempfile->filename.buf);
916         FREE_AND_NULL(midx_name);
917
918         if (packs.m)
919                 close_midx(packs.m);
920
921         cur_chunk = 0;
922         num_chunks = large_offsets_needed ? 5 : 4;
923
924         if (packs.nr - dropped_packs == 0) {
925                 error(_("no pack files to index."));
926                 result = 1;
927                 goto cleanup;
928         }
929
930         written = write_midx_header(f, num_chunks, packs.nr - dropped_packs);
931
932         chunk_ids[cur_chunk] = MIDX_CHUNKID_PACKNAMES;
933         chunk_offsets[cur_chunk] = written + (num_chunks + 1) * MIDX_CHUNKLOOKUP_WIDTH;
934
935         cur_chunk++;
936         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDFANOUT;
937         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + pack_name_concat_len;
938
939         cur_chunk++;
940         chunk_ids[cur_chunk] = MIDX_CHUNKID_OIDLOOKUP;
941         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + MIDX_CHUNK_FANOUT_SIZE;
942
943         cur_chunk++;
944         chunk_ids[cur_chunk] = MIDX_CHUNKID_OBJECTOFFSETS;
945         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * the_hash_algo->rawsz;
946
947         cur_chunk++;
948         chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] + nr_entries * MIDX_CHUNK_OFFSET_WIDTH;
949         if (large_offsets_needed) {
950                 chunk_ids[cur_chunk] = MIDX_CHUNKID_LARGEOFFSETS;
951
952                 cur_chunk++;
953                 chunk_offsets[cur_chunk] = chunk_offsets[cur_chunk - 1] +
954                                            num_large_offsets * MIDX_CHUNK_LARGE_OFFSET_WIDTH;
955         }
956
957         chunk_ids[cur_chunk] = 0;
958
959         for (i = 0; i <= num_chunks; i++) {
960                 if (i && chunk_offsets[i] < chunk_offsets[i - 1])
961                         BUG("incorrect chunk offsets: %"PRIu64" before %"PRIu64,
962                             chunk_offsets[i - 1],
963                             chunk_offsets[i]);
964
965                 if (chunk_offsets[i] % MIDX_CHUNK_ALIGNMENT)
966                         BUG("chunk offset %"PRIu64" is not properly aligned",
967                             chunk_offsets[i]);
968
969                 hashwrite_be32(f, chunk_ids[i]);
970                 hashwrite_be32(f, chunk_offsets[i] >> 32);
971                 hashwrite_be32(f, chunk_offsets[i]);
972
973                 written += MIDX_CHUNKLOOKUP_WIDTH;
974         }
975
976         if (flags & MIDX_PROGRESS)
977                 progress = start_progress(_("Writing chunks to multi-pack-index"),
978                                           num_chunks);
979         for (i = 0; i < num_chunks; i++) {
980                 if (written != chunk_offsets[i])
981                         BUG("incorrect chunk offset (%"PRIu64" != %"PRIu64") for chunk id %"PRIx32,
982                             chunk_offsets[i],
983                             written,
984                             chunk_ids[i]);
985
986                 switch (chunk_ids[i]) {
987                         case MIDX_CHUNKID_PACKNAMES:
988                                 written += write_midx_pack_names(f, packs.info, packs.nr);
989                                 break;
990
991                         case MIDX_CHUNKID_OIDFANOUT:
992                                 written += write_midx_oid_fanout(f, entries, nr_entries);
993                                 break;
994
995                         case MIDX_CHUNKID_OIDLOOKUP:
996                                 written += write_midx_oid_lookup(f, the_hash_algo->rawsz, entries, nr_entries);
997                                 break;
998
999                         case MIDX_CHUNKID_OBJECTOFFSETS:
1000                                 written += write_midx_object_offsets(f, large_offsets_needed, pack_perm, entries, nr_entries);
1001                                 break;
1002
1003                         case MIDX_CHUNKID_LARGEOFFSETS:
1004                                 written += write_midx_large_offsets(f, num_large_offsets, entries, nr_entries);
1005                                 break;
1006
1007                         default:
1008                                 BUG("trying to write unknown chunk id %"PRIx32,
1009                                     chunk_ids[i]);
1010                 }
1011
1012                 display_progress(progress, i + 1);
1013         }
1014         stop_progress(&progress);
1015
1016         if (written != chunk_offsets[num_chunks])
1017                 BUG("incorrect final offset %"PRIu64" != %"PRIu64,
1018                     written,
1019                     chunk_offsets[num_chunks]);
1020
1021         finalize_hashfile(f, NULL, CSUM_FSYNC | CSUM_HASH_IN_STREAM);
1022         commit_lock_file(&lk);
1023
1024 cleanup:
1025         for (i = 0; i < packs.nr; i++) {
1026                 if (packs.info[i].p) {
1027                         close_pack(packs.info[i].p);
1028                         free(packs.info[i].p);
1029                 }
1030                 free(packs.info[i].pack_name);
1031         }
1032
1033         free(packs.info);
1034         free(entries);
1035         free(pack_perm);
1036         free(midx_name);
1037         return result;
1038 }
1039
1040 int write_midx_file(const char *object_dir, unsigned flags)
1041 {
1042         return write_midx_internal(object_dir, NULL, NULL, flags);
1043 }
1044
1045 void clear_midx_file(struct repository *r)
1046 {
1047         char *midx = get_midx_filename(r->objects->odb->path);
1048
1049         if (r->objects && r->objects->multi_pack_index) {
1050                 close_midx(r->objects->multi_pack_index);
1051                 r->objects->multi_pack_index = NULL;
1052         }
1053
1054         if (remove_path(midx)) {
1055                 UNLEAK(midx);
1056                 die(_("failed to clear multi-pack-index at %s"), midx);
1057         }
1058
1059         free(midx);
1060 }
1061
1062 static int verify_midx_error;
1063
1064 static void midx_report(const char *fmt, ...)
1065 {
1066         va_list ap;
1067         verify_midx_error = 1;
1068         va_start(ap, fmt);
1069         vfprintf(stderr, fmt, ap);
1070         fprintf(stderr, "\n");
1071         va_end(ap);
1072 }
1073
1074 struct pair_pos_vs_id
1075 {
1076         uint32_t pos;
1077         uint32_t pack_int_id;
1078 };
1079
1080 static int compare_pair_pos_vs_id(const void *_a, const void *_b)
1081 {
1082         struct pair_pos_vs_id *a = (struct pair_pos_vs_id *)_a;
1083         struct pair_pos_vs_id *b = (struct pair_pos_vs_id *)_b;
1084
1085         return b->pack_int_id - a->pack_int_id;
1086 }
1087
1088 /*
1089  * Limit calls to display_progress() for performance reasons.
1090  * The interval here was arbitrarily chosen.
1091  */
1092 #define SPARSE_PROGRESS_INTERVAL (1 << 12)
1093 #define midx_display_sparse_progress(progress, n) \
1094         do { \
1095                 uint64_t _n = (n); \
1096                 if ((_n & (SPARSE_PROGRESS_INTERVAL - 1)) == 0) \
1097                         display_progress(progress, _n); \
1098         } while (0)
1099
1100 int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags)
1101 {
1102         struct pair_pos_vs_id *pairs = NULL;
1103         uint32_t i;
1104         struct progress *progress = NULL;
1105         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1106         verify_midx_error = 0;
1107
1108         if (!m)
1109                 return 0;
1110
1111         if (flags & MIDX_PROGRESS)
1112                 progress = start_progress(_("Looking for referenced packfiles"),
1113                                           m->num_packs);
1114         for (i = 0; i < m->num_packs; i++) {
1115                 if (prepare_midx_pack(r, m, i))
1116                         midx_report("failed to load pack in position %d", i);
1117
1118                 display_progress(progress, i + 1);
1119         }
1120         stop_progress(&progress);
1121
1122         for (i = 0; i < 255; i++) {
1123                 uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
1124                 uint32_t oid_fanout2 = ntohl(m->chunk_oid_fanout[i + 1]);
1125
1126                 if (oid_fanout1 > oid_fanout2)
1127                         midx_report(_("oid fanout out of order: fanout[%d] = %"PRIx32" > %"PRIx32" = fanout[%d]"),
1128                                     i, oid_fanout1, oid_fanout2, i + 1);
1129         }
1130
1131         if (m->num_objects == 0) {
1132                 midx_report(_("the midx contains no oid"));
1133                 /*
1134                  * Remaining tests assume that we have objects, so we can
1135                  * return here.
1136                  */
1137                 return verify_midx_error;
1138         }
1139
1140         if (flags & MIDX_PROGRESS)
1141                 progress = start_sparse_progress(_("Verifying OID order in multi-pack-index"),
1142                                                  m->num_objects - 1);
1143         for (i = 0; i < m->num_objects - 1; i++) {
1144                 struct object_id oid1, oid2;
1145
1146                 nth_midxed_object_oid(&oid1, m, i);
1147                 nth_midxed_object_oid(&oid2, m, i + 1);
1148
1149                 if (oidcmp(&oid1, &oid2) >= 0)
1150                         midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
1151                                     i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
1152
1153                 midx_display_sparse_progress(progress, i + 1);
1154         }
1155         stop_progress(&progress);
1156
1157         /*
1158          * Create an array mapping each object to its packfile id.  Sort it
1159          * to group the objects by packfile.  Use this permutation to visit
1160          * each of the objects and only require 1 packfile to be open at a
1161          * time.
1162          */
1163         ALLOC_ARRAY(pairs, m->num_objects);
1164         for (i = 0; i < m->num_objects; i++) {
1165                 pairs[i].pos = i;
1166                 pairs[i].pack_int_id = nth_midxed_pack_int_id(m, i);
1167         }
1168
1169         if (flags & MIDX_PROGRESS)
1170                 progress = start_sparse_progress(_("Sorting objects by packfile"),
1171                                                  m->num_objects);
1172         display_progress(progress, 0); /* TODO: Measure QSORT() progress */
1173         QSORT(pairs, m->num_objects, compare_pair_pos_vs_id);
1174         stop_progress(&progress);
1175
1176         if (flags & MIDX_PROGRESS)
1177                 progress = start_sparse_progress(_("Verifying object offsets"), m->num_objects);
1178         for (i = 0; i < m->num_objects; i++) {
1179                 struct object_id oid;
1180                 struct pack_entry e;
1181                 off_t m_offset, p_offset;
1182
1183                 if (i > 0 && pairs[i-1].pack_int_id != pairs[i].pack_int_id &&
1184                     m->packs[pairs[i-1].pack_int_id])
1185                 {
1186                         close_pack_fd(m->packs[pairs[i-1].pack_int_id]);
1187                         close_pack_index(m->packs[pairs[i-1].pack_int_id]);
1188                 }
1189
1190                 nth_midxed_object_oid(&oid, m, pairs[i].pos);
1191
1192                 if (!fill_midx_entry(r, &oid, &e, m)) {
1193                         midx_report(_("failed to load pack entry for oid[%d] = %s"),
1194                                     pairs[i].pos, oid_to_hex(&oid));
1195                         continue;
1196                 }
1197
1198                 if (open_pack_index(e.p)) {
1199                         midx_report(_("failed to load pack-index for packfile %s"),
1200                                     e.p->pack_name);
1201                         break;
1202                 }
1203
1204                 m_offset = e.offset;
1205                 p_offset = find_pack_entry_one(oid.hash, e.p);
1206
1207                 if (m_offset != p_offset)
1208                         midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
1209                                     pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
1210
1211                 midx_display_sparse_progress(progress, i + 1);
1212         }
1213         stop_progress(&progress);
1214
1215         free(pairs);
1216
1217         return verify_midx_error;
1218 }
1219
1220 int expire_midx_packs(struct repository *r, const char *object_dir, unsigned flags)
1221 {
1222         uint32_t i, *count, result = 0;
1223         struct string_list packs_to_drop = STRING_LIST_INIT_DUP;
1224         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1225         struct progress *progress = NULL;
1226
1227         if (!m)
1228                 return 0;
1229
1230         count = xcalloc(m->num_packs, sizeof(uint32_t));
1231
1232         if (flags & MIDX_PROGRESS)
1233                 progress = start_progress(_("Counting referenced objects"),
1234                                           m->num_objects);
1235         for (i = 0; i < m->num_objects; i++) {
1236                 int pack_int_id = nth_midxed_pack_int_id(m, i);
1237                 count[pack_int_id]++;
1238                 display_progress(progress, i + 1);
1239         }
1240         stop_progress(&progress);
1241
1242         if (flags & MIDX_PROGRESS)
1243                 progress = start_progress(_("Finding and deleting unreferenced packfiles"),
1244                                           m->num_packs);
1245         for (i = 0; i < m->num_packs; i++) {
1246                 char *pack_name;
1247                 display_progress(progress, i + 1);
1248
1249                 if (count[i])
1250                         continue;
1251
1252                 if (prepare_midx_pack(r, m, i))
1253                         continue;
1254
1255                 if (m->packs[i]->pack_keep)
1256                         continue;
1257
1258                 pack_name = xstrdup(m->packs[i]->pack_name);
1259                 close_pack(m->packs[i]);
1260
1261                 string_list_insert(&packs_to_drop, m->pack_names[i]);
1262                 unlink_pack_path(pack_name, 0);
1263                 free(pack_name);
1264         }
1265         stop_progress(&progress);
1266
1267         free(count);
1268
1269         if (packs_to_drop.nr)
1270                 result = write_midx_internal(object_dir, m, &packs_to_drop, flags);
1271
1272         string_list_clear(&packs_to_drop, 0);
1273         return result;
1274 }
1275
1276 struct repack_info {
1277         timestamp_t mtime;
1278         uint32_t referenced_objects;
1279         uint32_t pack_int_id;
1280 };
1281
1282 static int compare_by_mtime(const void *a_, const void *b_)
1283 {
1284         const struct repack_info *a, *b;
1285
1286         a = (const struct repack_info *)a_;
1287         b = (const struct repack_info *)b_;
1288
1289         if (a->mtime < b->mtime)
1290                 return -1;
1291         if (a->mtime > b->mtime)
1292                 return 1;
1293         return 0;
1294 }
1295
1296 static int fill_included_packs_all(struct repository *r,
1297                                    struct multi_pack_index *m,
1298                                    unsigned char *include_pack)
1299 {
1300         uint32_t i, count = 0;
1301         int pack_kept_objects = 0;
1302
1303         repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
1304
1305         for (i = 0; i < m->num_packs; i++) {
1306                 if (prepare_midx_pack(r, m, i))
1307                         continue;
1308                 if (!pack_kept_objects && m->packs[i]->pack_keep)
1309                         continue;
1310
1311                 include_pack[i] = 1;
1312                 count++;
1313         }
1314
1315         return count < 2;
1316 }
1317
1318 static int fill_included_packs_batch(struct repository *r,
1319                                      struct multi_pack_index *m,
1320                                      unsigned char *include_pack,
1321                                      size_t batch_size)
1322 {
1323         uint32_t i, packs_to_repack;
1324         size_t total_size;
1325         struct repack_info *pack_info = xcalloc(m->num_packs, sizeof(struct repack_info));
1326         int pack_kept_objects = 0;
1327
1328         repo_config_get_bool(r, "repack.packkeptobjects", &pack_kept_objects);
1329
1330         for (i = 0; i < m->num_packs; i++) {
1331                 pack_info[i].pack_int_id = i;
1332
1333                 if (prepare_midx_pack(r, m, i))
1334                         continue;
1335
1336                 pack_info[i].mtime = m->packs[i]->mtime;
1337         }
1338
1339         for (i = 0; batch_size && i < m->num_objects; i++) {
1340                 uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
1341                 pack_info[pack_int_id].referenced_objects++;
1342         }
1343
1344         QSORT(pack_info, m->num_packs, compare_by_mtime);
1345
1346         total_size = 0;
1347         packs_to_repack = 0;
1348         for (i = 0; total_size < batch_size && i < m->num_packs; i++) {
1349                 int pack_int_id = pack_info[i].pack_int_id;
1350                 struct packed_git *p = m->packs[pack_int_id];
1351                 size_t expected_size;
1352
1353                 if (!p)
1354                         continue;
1355                 if (!pack_kept_objects && p->pack_keep)
1356                         continue;
1357                 if (open_pack_index(p) || !p->num_objects)
1358                         continue;
1359
1360                 expected_size = (size_t)(p->pack_size
1361                                          * pack_info[i].referenced_objects);
1362                 expected_size /= p->num_objects;
1363
1364                 if (expected_size >= batch_size)
1365                         continue;
1366
1367                 packs_to_repack++;
1368                 total_size += expected_size;
1369                 include_pack[pack_int_id] = 1;
1370         }
1371
1372         free(pack_info);
1373
1374         if (total_size < batch_size || packs_to_repack < 2)
1375                 return 1;
1376
1377         return 0;
1378 }
1379
1380 int midx_repack(struct repository *r, const char *object_dir, size_t batch_size, unsigned flags)
1381 {
1382         int result = 0;
1383         uint32_t i;
1384         unsigned char *include_pack;
1385         struct child_process cmd = CHILD_PROCESS_INIT;
1386         struct strbuf base_name = STRBUF_INIT;
1387         struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
1388
1389         /*
1390          * When updating the default for these configuration
1391          * variables in builtin/repack.c, these must be adjusted
1392          * to match.
1393          */
1394         int delta_base_offset = 1;
1395         int use_delta_islands = 0;
1396
1397         if (!m)
1398                 return 0;
1399
1400         include_pack = xcalloc(m->num_packs, sizeof(unsigned char));
1401
1402         if (batch_size) {
1403                 if (fill_included_packs_batch(r, m, include_pack, batch_size))
1404                         goto cleanup;
1405         } else if (fill_included_packs_all(r, m, include_pack))
1406                 goto cleanup;
1407
1408         repo_config_get_bool(r, "repack.usedeltabaseoffset", &delta_base_offset);
1409         repo_config_get_bool(r, "repack.usedeltaislands", &use_delta_islands);
1410
1411         argv_array_push(&cmd.args, "pack-objects");
1412
1413         strbuf_addstr(&base_name, object_dir);
1414         strbuf_addstr(&base_name, "/pack/pack");
1415         argv_array_push(&cmd.args, base_name.buf);
1416
1417         if (delta_base_offset)
1418                 argv_array_push(&cmd.args, "--delta-base-offset");
1419         if (use_delta_islands)
1420                 argv_array_push(&cmd.args, "--delta-islands");
1421
1422         if (flags & MIDX_PROGRESS)
1423                 argv_array_push(&cmd.args, "--progress");
1424         else
1425                 argv_array_push(&cmd.args, "-q");
1426
1427         strbuf_release(&base_name);
1428
1429         cmd.git_cmd = 1;
1430         cmd.in = cmd.out = -1;
1431
1432         if (start_command(&cmd)) {
1433                 error(_("could not start pack-objects"));
1434                 result = 1;
1435                 goto cleanup;
1436         }
1437
1438         for (i = 0; i < m->num_objects; i++) {
1439                 struct object_id oid;
1440                 uint32_t pack_int_id = nth_midxed_pack_int_id(m, i);
1441
1442                 if (!include_pack[pack_int_id])
1443                         continue;
1444
1445                 nth_midxed_object_oid(&oid, m, i);
1446                 xwrite(cmd.in, oid_to_hex(&oid), the_hash_algo->hexsz);
1447                 xwrite(cmd.in, "\n", 1);
1448         }
1449         close(cmd.in);
1450
1451         if (finish_command(&cmd)) {
1452                 error(_("could not finish pack-objects"));
1453                 result = 1;
1454                 goto cleanup;
1455         }
1456
1457         result = write_midx_internal(object_dir, m, NULL, flags);
1458         m = NULL;
1459
1460 cleanup:
1461         if (m)
1462                 close_midx(m);
1463         free(include_pack);
1464         return result;
1465 }