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