Merge branch 'pt/t0302-needs-sanity'
[git] / builtin / index-pack.c
1 #include "builtin.h"
2 #include "delta.h"
3 #include "pack.h"
4 #include "csum-file.h"
5 #include "blob.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "tree.h"
9 #include "progress.h"
10 #include "fsck.h"
11 #include "exec_cmd.h"
12 #include "streaming.h"
13 #include "thread-utils.h"
14
15 static const char index_pack_usage[] =
16 "git index-pack [-v] [-o <index-file>] [--keep | --keep=<msg>] [--verify] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
17
18 struct object_entry {
19         struct pack_idx_entry idx;
20         unsigned long size;
21         unsigned char hdr_size;
22         signed char type;
23         signed char real_type;
24 };
25
26 struct object_stat {
27         unsigned delta_depth;
28         int base_object_no;
29 };
30
31 struct base_data {
32         struct base_data *base;
33         struct base_data *child;
34         struct object_entry *obj;
35         void *data;
36         unsigned long size;
37         int ref_first, ref_last;
38         int ofs_first, ofs_last;
39 };
40
41 struct thread_local {
42 #ifndef NO_PTHREADS
43         pthread_t thread;
44 #endif
45         struct base_data *base_cache;
46         size_t base_cache_used;
47         int pack_fd;
48 };
49
50 #define FLAG_LINK (1u<<20)
51 #define FLAG_CHECKED (1u<<21)
52
53 struct ofs_delta_entry {
54         off_t offset;
55         int obj_no;
56 };
57
58 struct ref_delta_entry {
59         unsigned char sha1[20];
60         int obj_no;
61 };
62
63 static struct object_entry *objects;
64 static struct object_stat *obj_stat;
65 static struct ofs_delta_entry *ofs_deltas;
66 static struct ref_delta_entry *ref_deltas;
67 static struct thread_local nothread_data;
68 static int nr_objects;
69 static int nr_ofs_deltas;
70 static int nr_ref_deltas;
71 static int ref_deltas_alloc;
72 static int nr_resolved_deltas;
73 static int nr_threads;
74
75 static int from_stdin;
76 static int strict;
77 static int do_fsck_object;
78 static int verbose;
79 static int show_stat;
80 static int check_self_contained_and_connected;
81
82 static struct progress *progress;
83
84 /* We always read in 4kB chunks. */
85 static unsigned char input_buffer[4096];
86 static unsigned int input_offset, input_len;
87 static off_t consumed_bytes;
88 static unsigned deepest_delta;
89 static git_SHA_CTX input_ctx;
90 static uint32_t input_crc32;
91 static int input_fd, output_fd;
92 static const char *curr_pack;
93
94 #ifndef NO_PTHREADS
95
96 static struct thread_local *thread_data;
97 static int nr_dispatched;
98 static int threads_active;
99
100 static pthread_mutex_t read_mutex;
101 #define read_lock()             lock_mutex(&read_mutex)
102 #define read_unlock()           unlock_mutex(&read_mutex)
103
104 static pthread_mutex_t counter_mutex;
105 #define counter_lock()          lock_mutex(&counter_mutex)
106 #define counter_unlock()        unlock_mutex(&counter_mutex)
107
108 static pthread_mutex_t work_mutex;
109 #define work_lock()             lock_mutex(&work_mutex)
110 #define work_unlock()           unlock_mutex(&work_mutex)
111
112 static pthread_mutex_t deepest_delta_mutex;
113 #define deepest_delta_lock()    lock_mutex(&deepest_delta_mutex)
114 #define deepest_delta_unlock()  unlock_mutex(&deepest_delta_mutex)
115
116 static pthread_mutex_t type_cas_mutex;
117 #define type_cas_lock()         lock_mutex(&type_cas_mutex)
118 #define type_cas_unlock()       unlock_mutex(&type_cas_mutex)
119
120 static pthread_key_t key;
121
122 static inline void lock_mutex(pthread_mutex_t *mutex)
123 {
124         if (threads_active)
125                 pthread_mutex_lock(mutex);
126 }
127
128 static inline void unlock_mutex(pthread_mutex_t *mutex)
129 {
130         if (threads_active)
131                 pthread_mutex_unlock(mutex);
132 }
133
134 /*
135  * Mutex and conditional variable can't be statically-initialized on Windows.
136  */
137 static void init_thread(void)
138 {
139         int i;
140         init_recursive_mutex(&read_mutex);
141         pthread_mutex_init(&counter_mutex, NULL);
142         pthread_mutex_init(&work_mutex, NULL);
143         pthread_mutex_init(&type_cas_mutex, NULL);
144         if (show_stat)
145                 pthread_mutex_init(&deepest_delta_mutex, NULL);
146         pthread_key_create(&key, NULL);
147         thread_data = xcalloc(nr_threads, sizeof(*thread_data));
148         for (i = 0; i < nr_threads; i++) {
149                 thread_data[i].pack_fd = open(curr_pack, O_RDONLY);
150                 if (thread_data[i].pack_fd == -1)
151                         die_errno(_("unable to open %s"), curr_pack);
152         }
153
154         threads_active = 1;
155 }
156
157 static void cleanup_thread(void)
158 {
159         int i;
160         if (!threads_active)
161                 return;
162         threads_active = 0;
163         pthread_mutex_destroy(&read_mutex);
164         pthread_mutex_destroy(&counter_mutex);
165         pthread_mutex_destroy(&work_mutex);
166         pthread_mutex_destroy(&type_cas_mutex);
167         if (show_stat)
168                 pthread_mutex_destroy(&deepest_delta_mutex);
169         for (i = 0; i < nr_threads; i++)
170                 close(thread_data[i].pack_fd);
171         pthread_key_delete(key);
172         free(thread_data);
173 }
174
175 #else
176
177 #define read_lock()
178 #define read_unlock()
179
180 #define counter_lock()
181 #define counter_unlock()
182
183 #define work_lock()
184 #define work_unlock()
185
186 #define deepest_delta_lock()
187 #define deepest_delta_unlock()
188
189 #define type_cas_lock()
190 #define type_cas_unlock()
191
192 #endif
193
194
195 static int mark_link(struct object *obj, int type, void *data)
196 {
197         if (!obj)
198                 return -1;
199
200         if (type != OBJ_ANY && obj->type != type)
201                 die(_("object type mismatch at %s"), sha1_to_hex(obj->sha1));
202
203         obj->flags |= FLAG_LINK;
204         return 0;
205 }
206
207 /* The content of each linked object must have been checked
208    or it must be already present in the object database */
209 static unsigned check_object(struct object *obj)
210 {
211         if (!obj)
212                 return 0;
213
214         if (!(obj->flags & FLAG_LINK))
215                 return 0;
216
217         if (!(obj->flags & FLAG_CHECKED)) {
218                 unsigned long size;
219                 int type = sha1_object_info(obj->sha1, &size);
220                 if (type <= 0)
221                         die(_("did not receive expected object %s"),
222                               sha1_to_hex(obj->sha1));
223                 if (type != obj->type)
224                         die(_("object %s: expected type %s, found %s"),
225                             sha1_to_hex(obj->sha1),
226                             typename(obj->type), typename(type));
227                 obj->flags |= FLAG_CHECKED;
228                 return 1;
229         }
230
231         return 0;
232 }
233
234 static unsigned check_objects(void)
235 {
236         unsigned i, max, foreign_nr = 0;
237
238         max = get_max_object_index();
239         for (i = 0; i < max; i++)
240                 foreign_nr += check_object(get_indexed_object(i));
241         return foreign_nr;
242 }
243
244
245 /* Discard current buffer used content. */
246 static void flush(void)
247 {
248         if (input_offset) {
249                 if (output_fd >= 0)
250                         write_or_die(output_fd, input_buffer, input_offset);
251                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
252                 memmove(input_buffer, input_buffer + input_offset, input_len);
253                 input_offset = 0;
254         }
255 }
256
257 /*
258  * Make sure at least "min" bytes are available in the buffer, and
259  * return the pointer to the buffer.
260  */
261 static void *fill(int min)
262 {
263         if (min <= input_len)
264                 return input_buffer + input_offset;
265         if (min > sizeof(input_buffer))
266                 die(Q_("cannot fill %d byte",
267                        "cannot fill %d bytes",
268                        min),
269                     min);
270         flush();
271         do {
272                 ssize_t ret = xread(input_fd, input_buffer + input_len,
273                                 sizeof(input_buffer) - input_len);
274                 if (ret <= 0) {
275                         if (!ret)
276                                 die(_("early EOF"));
277                         die_errno(_("read error on input"));
278                 }
279                 input_len += ret;
280                 if (from_stdin)
281                         display_throughput(progress, consumed_bytes + input_len);
282         } while (input_len < min);
283         return input_buffer;
284 }
285
286 static void use(int bytes)
287 {
288         if (bytes > input_len)
289                 die(_("used more bytes than were available"));
290         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
291         input_len -= bytes;
292         input_offset += bytes;
293
294         /* make sure off_t is sufficiently large not to wrap */
295         if (signed_add_overflows(consumed_bytes, bytes))
296                 die(_("pack too large for current definition of off_t"));
297         consumed_bytes += bytes;
298 }
299
300 static const char *open_pack_file(const char *pack_name)
301 {
302         if (from_stdin) {
303                 input_fd = 0;
304                 if (!pack_name) {
305                         static char tmp_file[PATH_MAX];
306                         output_fd = odb_mkstemp(tmp_file, sizeof(tmp_file),
307                                                 "pack/tmp_pack_XXXXXX");
308                         pack_name = xstrdup(tmp_file);
309                 } else
310                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
311                 if (output_fd < 0)
312                         die_errno(_("unable to create '%s'"), pack_name);
313                 nothread_data.pack_fd = output_fd;
314         } else {
315                 input_fd = open(pack_name, O_RDONLY);
316                 if (input_fd < 0)
317                         die_errno(_("cannot open packfile '%s'"), pack_name);
318                 output_fd = -1;
319                 nothread_data.pack_fd = input_fd;
320         }
321         git_SHA1_Init(&input_ctx);
322         return pack_name;
323 }
324
325 static void parse_pack_header(void)
326 {
327         struct pack_header *hdr = fill(sizeof(struct pack_header));
328
329         /* Header consistency check */
330         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
331                 die(_("pack signature mismatch"));
332         if (!pack_version_ok(hdr->hdr_version))
333                 die(_("pack version %"PRIu32" unsupported"),
334                         ntohl(hdr->hdr_version));
335
336         nr_objects = ntohl(hdr->hdr_entries);
337         use(sizeof(struct pack_header));
338 }
339
340 static NORETURN void bad_object(unsigned long offset, const char *format,
341                        ...) __attribute__((format (printf, 2, 3)));
342
343 static NORETURN void bad_object(unsigned long offset, const char *format, ...)
344 {
345         va_list params;
346         char buf[1024];
347
348         va_start(params, format);
349         vsnprintf(buf, sizeof(buf), format, params);
350         va_end(params);
351         die(_("pack has bad object at offset %lu: %s"), offset, buf);
352 }
353
354 static inline struct thread_local *get_thread_data(void)
355 {
356 #ifndef NO_PTHREADS
357         if (threads_active)
358                 return pthread_getspecific(key);
359         assert(!threads_active &&
360                "This should only be reached when all threads are gone");
361 #endif
362         return &nothread_data;
363 }
364
365 #ifndef NO_PTHREADS
366 static void set_thread_data(struct thread_local *data)
367 {
368         if (threads_active)
369                 pthread_setspecific(key, data);
370 }
371 #endif
372
373 static struct base_data *alloc_base_data(void)
374 {
375         struct base_data *base = xcalloc(1, sizeof(struct base_data));
376         base->ref_last = -1;
377         base->ofs_last = -1;
378         return base;
379 }
380
381 static void free_base_data(struct base_data *c)
382 {
383         if (c->data) {
384                 free(c->data);
385                 c->data = NULL;
386                 get_thread_data()->base_cache_used -= c->size;
387         }
388 }
389
390 static void prune_base_data(struct base_data *retain)
391 {
392         struct base_data *b;
393         struct thread_local *data = get_thread_data();
394         for (b = data->base_cache;
395              data->base_cache_used > delta_base_cache_limit && b;
396              b = b->child) {
397                 if (b->data && b != retain)
398                         free_base_data(b);
399         }
400 }
401
402 static void link_base_data(struct base_data *base, struct base_data *c)
403 {
404         if (base)
405                 base->child = c;
406         else
407                 get_thread_data()->base_cache = c;
408
409         c->base = base;
410         c->child = NULL;
411         if (c->data)
412                 get_thread_data()->base_cache_used += c->size;
413         prune_base_data(c);
414 }
415
416 static void unlink_base_data(struct base_data *c)
417 {
418         struct base_data *base = c->base;
419         if (base)
420                 base->child = NULL;
421         else
422                 get_thread_data()->base_cache = NULL;
423         free_base_data(c);
424 }
425
426 static int is_delta_type(enum object_type type)
427 {
428         return (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA);
429 }
430
431 static void *unpack_entry_data(unsigned long offset, unsigned long size,
432                                enum object_type type, unsigned char *sha1)
433 {
434         static char fixed_buf[8192];
435         int status;
436         git_zstream stream;
437         void *buf;
438         git_SHA_CTX c;
439         char hdr[32];
440         int hdrlen;
441
442         if (!is_delta_type(type)) {
443                 hdrlen = sprintf(hdr, "%s %lu", typename(type), size) + 1;
444                 git_SHA1_Init(&c);
445                 git_SHA1_Update(&c, hdr, hdrlen);
446         } else
447                 sha1 = NULL;
448         if (type == OBJ_BLOB && size > big_file_threshold)
449                 buf = fixed_buf;
450         else
451                 buf = xmallocz(size);
452
453         memset(&stream, 0, sizeof(stream));
454         git_inflate_init(&stream);
455         stream.next_out = buf;
456         stream.avail_out = buf == fixed_buf ? sizeof(fixed_buf) : size;
457
458         do {
459                 unsigned char *last_out = stream.next_out;
460                 stream.next_in = fill(1);
461                 stream.avail_in = input_len;
462                 status = git_inflate(&stream, 0);
463                 use(input_len - stream.avail_in);
464                 if (sha1)
465                         git_SHA1_Update(&c, last_out, stream.next_out - last_out);
466                 if (buf == fixed_buf) {
467                         stream.next_out = buf;
468                         stream.avail_out = sizeof(fixed_buf);
469                 }
470         } while (status == Z_OK);
471         if (stream.total_out != size || status != Z_STREAM_END)
472                 bad_object(offset, _("inflate returned %d"), status);
473         git_inflate_end(&stream);
474         if (sha1)
475                 git_SHA1_Final(sha1, &c);
476         return buf == fixed_buf ? NULL : buf;
477 }
478
479 static void *unpack_raw_entry(struct object_entry *obj,
480                               off_t *ofs_offset,
481                               unsigned char *ref_sha1,
482                               unsigned char *sha1)
483 {
484         unsigned char *p;
485         unsigned long size, c;
486         off_t base_offset;
487         unsigned shift;
488         void *data;
489
490         obj->idx.offset = consumed_bytes;
491         input_crc32 = crc32(0, NULL, 0);
492
493         p = fill(1);
494         c = *p;
495         use(1);
496         obj->type = (c >> 4) & 7;
497         size = (c & 15);
498         shift = 4;
499         while (c & 0x80) {
500                 p = fill(1);
501                 c = *p;
502                 use(1);
503                 size += (c & 0x7f) << shift;
504                 shift += 7;
505         }
506         obj->size = size;
507
508         switch (obj->type) {
509         case OBJ_REF_DELTA:
510                 hashcpy(ref_sha1, fill(20));
511                 use(20);
512                 break;
513         case OBJ_OFS_DELTA:
514                 p = fill(1);
515                 c = *p;
516                 use(1);
517                 base_offset = c & 127;
518                 while (c & 128) {
519                         base_offset += 1;
520                         if (!base_offset || MSB(base_offset, 7))
521                                 bad_object(obj->idx.offset, _("offset value overflow for delta base object"));
522                         p = fill(1);
523                         c = *p;
524                         use(1);
525                         base_offset = (base_offset << 7) + (c & 127);
526                 }
527                 *ofs_offset = obj->idx.offset - base_offset;
528                 if (*ofs_offset <= 0 || *ofs_offset >= obj->idx.offset)
529                         bad_object(obj->idx.offset, _("delta base offset is out of bound"));
530                 break;
531         case OBJ_COMMIT:
532         case OBJ_TREE:
533         case OBJ_BLOB:
534         case OBJ_TAG:
535                 break;
536         default:
537                 bad_object(obj->idx.offset, _("unknown object type %d"), obj->type);
538         }
539         obj->hdr_size = consumed_bytes - obj->idx.offset;
540
541         data = unpack_entry_data(obj->idx.offset, obj->size, obj->type, sha1);
542         obj->idx.crc32 = input_crc32;
543         return data;
544 }
545
546 static void *unpack_data(struct object_entry *obj,
547                          int (*consume)(const unsigned char *, unsigned long, void *),
548                          void *cb_data)
549 {
550         off_t from = obj[0].idx.offset + obj[0].hdr_size;
551         unsigned long len = obj[1].idx.offset - from;
552         unsigned char *data, *inbuf;
553         git_zstream stream;
554         int status;
555
556         data = xmallocz(consume ? 64*1024 : obj->size);
557         inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
558
559         memset(&stream, 0, sizeof(stream));
560         git_inflate_init(&stream);
561         stream.next_out = data;
562         stream.avail_out = consume ? 64*1024 : obj->size;
563
564         do {
565                 ssize_t n = (len < 64*1024) ? len : 64*1024;
566                 n = xpread(get_thread_data()->pack_fd, inbuf, n, from);
567                 if (n < 0)
568                         die_errno(_("cannot pread pack file"));
569                 if (!n)
570                         die(Q_("premature end of pack file, %lu byte missing",
571                                "premature end of pack file, %lu bytes missing",
572                                len),
573                             len);
574                 from += n;
575                 len -= n;
576                 stream.next_in = inbuf;
577                 stream.avail_in = n;
578                 if (!consume)
579                         status = git_inflate(&stream, 0);
580                 else {
581                         do {
582                                 status = git_inflate(&stream, 0);
583                                 if (consume(data, stream.next_out - data, cb_data)) {
584                                         free(inbuf);
585                                         free(data);
586                                         return NULL;
587                                 }
588                                 stream.next_out = data;
589                                 stream.avail_out = 64*1024;
590                         } while (status == Z_OK && stream.avail_in);
591                 }
592         } while (len && status == Z_OK && !stream.avail_in);
593
594         /* This has been inflated OK when first encountered, so... */
595         if (status != Z_STREAM_END || stream.total_out != obj->size)
596                 die(_("serious inflate inconsistency"));
597
598         git_inflate_end(&stream);
599         free(inbuf);
600         if (consume) {
601                 free(data);
602                 data = NULL;
603         }
604         return data;
605 }
606
607 static void *get_data_from_pack(struct object_entry *obj)
608 {
609         return unpack_data(obj, NULL, NULL);
610 }
611
612 static int compare_ofs_delta_bases(off_t offset1, off_t offset2,
613                                    enum object_type type1,
614                                    enum object_type type2)
615 {
616         int cmp = type1 - type2;
617         if (cmp)
618                 return cmp;
619         return offset1 < offset2 ? -1 :
620                offset1 > offset2 ?  1 :
621                0;
622 }
623
624 static int find_ofs_delta(const off_t offset, enum object_type type)
625 {
626         int first = 0, last = nr_ofs_deltas;
627
628         while (first < last) {
629                 int next = (first + last) / 2;
630                 struct ofs_delta_entry *delta = &ofs_deltas[next];
631                 int cmp;
632
633                 cmp = compare_ofs_delta_bases(offset, delta->offset,
634                                               type, objects[delta->obj_no].type);
635                 if (!cmp)
636                         return next;
637                 if (cmp < 0) {
638                         last = next;
639                         continue;
640                 }
641                 first = next+1;
642         }
643         return -first-1;
644 }
645
646 static void find_ofs_delta_children(off_t offset,
647                                     int *first_index, int *last_index,
648                                     enum object_type type)
649 {
650         int first = find_ofs_delta(offset, type);
651         int last = first;
652         int end = nr_ofs_deltas - 1;
653
654         if (first < 0) {
655                 *first_index = 0;
656                 *last_index = -1;
657                 return;
658         }
659         while (first > 0 && ofs_deltas[first - 1].offset == offset)
660                 --first;
661         while (last < end && ofs_deltas[last + 1].offset == offset)
662                 ++last;
663         *first_index = first;
664         *last_index = last;
665 }
666
667 static int compare_ref_delta_bases(const unsigned char *sha1,
668                                    const unsigned char *sha2,
669                                    enum object_type type1,
670                                    enum object_type type2)
671 {
672         int cmp = type1 - type2;
673         if (cmp)
674                 return cmp;
675         return hashcmp(sha1, sha2);
676 }
677
678 static int find_ref_delta(const unsigned char *sha1, enum object_type type)
679 {
680         int first = 0, last = nr_ref_deltas;
681
682         while (first < last) {
683                 int next = (first + last) / 2;
684                 struct ref_delta_entry *delta = &ref_deltas[next];
685                 int cmp;
686
687                 cmp = compare_ref_delta_bases(sha1, delta->sha1,
688                                               type, objects[delta->obj_no].type);
689                 if (!cmp)
690                         return next;
691                 if (cmp < 0) {
692                         last = next;
693                         continue;
694                 }
695                 first = next+1;
696         }
697         return -first-1;
698 }
699
700 static void find_ref_delta_children(const unsigned char *sha1,
701                                     int *first_index, int *last_index,
702                                     enum object_type type)
703 {
704         int first = find_ref_delta(sha1, type);
705         int last = first;
706         int end = nr_ref_deltas - 1;
707
708         if (first < 0) {
709                 *first_index = 0;
710                 *last_index = -1;
711                 return;
712         }
713         while (first > 0 && !hashcmp(ref_deltas[first - 1].sha1, sha1))
714                 --first;
715         while (last < end && !hashcmp(ref_deltas[last + 1].sha1, sha1))
716                 ++last;
717         *first_index = first;
718         *last_index = last;
719 }
720
721 struct compare_data {
722         struct object_entry *entry;
723         struct git_istream *st;
724         unsigned char *buf;
725         unsigned long buf_size;
726 };
727
728 static int compare_objects(const unsigned char *buf, unsigned long size,
729                            void *cb_data)
730 {
731         struct compare_data *data = cb_data;
732
733         if (data->buf_size < size) {
734                 free(data->buf);
735                 data->buf = xmalloc(size);
736                 data->buf_size = size;
737         }
738
739         while (size) {
740                 ssize_t len = read_istream(data->st, data->buf, size);
741                 if (len == 0)
742                         die(_("SHA1 COLLISION FOUND WITH %s !"),
743                             sha1_to_hex(data->entry->idx.sha1));
744                 if (len < 0)
745                         die(_("unable to read %s"),
746                             sha1_to_hex(data->entry->idx.sha1));
747                 if (memcmp(buf, data->buf, len))
748                         die(_("SHA1 COLLISION FOUND WITH %s !"),
749                             sha1_to_hex(data->entry->idx.sha1));
750                 size -= len;
751                 buf += len;
752         }
753         return 0;
754 }
755
756 static int check_collison(struct object_entry *entry)
757 {
758         struct compare_data data;
759         enum object_type type;
760         unsigned long size;
761
762         if (entry->size <= big_file_threshold || entry->type != OBJ_BLOB)
763                 return -1;
764
765         memset(&data, 0, sizeof(data));
766         data.entry = entry;
767         data.st = open_istream(entry->idx.sha1, &type, &size, NULL);
768         if (!data.st)
769                 return -1;
770         if (size != entry->size || type != entry->type)
771                 die(_("SHA1 COLLISION FOUND WITH %s !"),
772                     sha1_to_hex(entry->idx.sha1));
773         unpack_data(entry, compare_objects, &data);
774         close_istream(data.st);
775         free(data.buf);
776         return 0;
777 }
778
779 static void sha1_object(const void *data, struct object_entry *obj_entry,
780                         unsigned long size, enum object_type type,
781                         const unsigned char *sha1)
782 {
783         void *new_data = NULL;
784         int collision_test_needed;
785
786         assert(data || obj_entry);
787
788         read_lock();
789         collision_test_needed = has_sha1_file_with_flags(sha1, HAS_SHA1_QUICK);
790         read_unlock();
791
792         if (collision_test_needed && !data) {
793                 read_lock();
794                 if (!check_collison(obj_entry))
795                         collision_test_needed = 0;
796                 read_unlock();
797         }
798         if (collision_test_needed) {
799                 void *has_data;
800                 enum object_type has_type;
801                 unsigned long has_size;
802                 read_lock();
803                 has_type = sha1_object_info(sha1, &has_size);
804                 if (has_type != type || has_size != size)
805                         die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
806                 has_data = read_sha1_file(sha1, &has_type, &has_size);
807                 read_unlock();
808                 if (!data)
809                         data = new_data = get_data_from_pack(obj_entry);
810                 if (!has_data)
811                         die(_("cannot read existing object %s"), sha1_to_hex(sha1));
812                 if (size != has_size || type != has_type ||
813                     memcmp(data, has_data, size) != 0)
814                         die(_("SHA1 COLLISION FOUND WITH %s !"), sha1_to_hex(sha1));
815                 free(has_data);
816         }
817
818         if (strict) {
819                 read_lock();
820                 if (type == OBJ_BLOB) {
821                         struct blob *blob = lookup_blob(sha1);
822                         if (blob)
823                                 blob->object.flags |= FLAG_CHECKED;
824                         else
825                                 die(_("invalid blob object %s"), sha1_to_hex(sha1));
826                 } else {
827                         struct object *obj;
828                         int eaten;
829                         void *buf = (void *) data;
830
831                         assert(data && "data can only be NULL for large _blobs_");
832
833                         /*
834                          * we do not need to free the memory here, as the
835                          * buf is deleted by the caller.
836                          */
837                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
838                         if (!obj)
839                                 die(_("invalid %s"), typename(type));
840                         if (do_fsck_object &&
841                             fsck_object(obj, buf, size, 1,
842                                     fsck_error_function))
843                                 die(_("Error in object"));
844                         if (fsck_walk(obj, mark_link, NULL))
845                                 die(_("Not all child objects of %s are reachable"), sha1_to_hex(obj->sha1));
846
847                         if (obj->type == OBJ_TREE) {
848                                 struct tree *item = (struct tree *) obj;
849                                 item->buffer = NULL;
850                                 obj->parsed = 0;
851                         }
852                         if (obj->type == OBJ_COMMIT) {
853                                 struct commit *commit = (struct commit *) obj;
854                                 if (detach_commit_buffer(commit, NULL) != data)
855                                         die("BUG: parse_object_buffer transmogrified our buffer");
856                         }
857                         obj->flags |= FLAG_CHECKED;
858                 }
859                 read_unlock();
860         }
861
862         free(new_data);
863 }
864
865 /*
866  * This function is part of find_unresolved_deltas(). There are two
867  * walkers going in the opposite ways.
868  *
869  * The first one in find_unresolved_deltas() traverses down from
870  * parent node to children, deflating nodes along the way. However,
871  * memory for deflated nodes is limited by delta_base_cache_limit, so
872  * at some point parent node's deflated content may be freed.
873  *
874  * The second walker is this function, which goes from current node up
875  * to top parent if necessary to deflate the node. In normal
876  * situation, its parent node would be already deflated, so it just
877  * needs to apply delta.
878  *
879  * In the worst case scenario, parent node is no longer deflated because
880  * we're running out of delta_base_cache_limit; we need to re-deflate
881  * parents, possibly up to the top base.
882  *
883  * All deflated objects here are subject to be freed if we exceed
884  * delta_base_cache_limit, just like in find_unresolved_deltas(), we
885  * just need to make sure the last node is not freed.
886  */
887 static void *get_base_data(struct base_data *c)
888 {
889         if (!c->data) {
890                 struct object_entry *obj = c->obj;
891                 struct base_data **delta = NULL;
892                 int delta_nr = 0, delta_alloc = 0;
893
894                 while (is_delta_type(c->obj->type) && !c->data) {
895                         ALLOC_GROW(delta, delta_nr + 1, delta_alloc);
896                         delta[delta_nr++] = c;
897                         c = c->base;
898                 }
899                 if (!delta_nr) {
900                         c->data = get_data_from_pack(obj);
901                         c->size = obj->size;
902                         get_thread_data()->base_cache_used += c->size;
903                         prune_base_data(c);
904                 }
905                 for (; delta_nr > 0; delta_nr--) {
906                         void *base, *raw;
907                         c = delta[delta_nr - 1];
908                         obj = c->obj;
909                         base = get_base_data(c->base);
910                         raw = get_data_from_pack(obj);
911                         c->data = patch_delta(
912                                 base, c->base->size,
913                                 raw, obj->size,
914                                 &c->size);
915                         free(raw);
916                         if (!c->data)
917                                 bad_object(obj->idx.offset, _("failed to apply delta"));
918                         get_thread_data()->base_cache_used += c->size;
919                         prune_base_data(c);
920                 }
921                 free(delta);
922         }
923         return c->data;
924 }
925
926 static void resolve_delta(struct object_entry *delta_obj,
927                           struct base_data *base, struct base_data *result)
928 {
929         void *base_data, *delta_data;
930
931         if (show_stat) {
932                 int i = delta_obj - objects;
933                 int j = base->obj - objects;
934                 obj_stat[i].delta_depth = obj_stat[j].delta_depth + 1;
935                 deepest_delta_lock();
936                 if (deepest_delta < obj_stat[i].delta_depth)
937                         deepest_delta = obj_stat[i].delta_depth;
938                 deepest_delta_unlock();
939                 obj_stat[i].base_object_no = j;
940         }
941         delta_data = get_data_from_pack(delta_obj);
942         base_data = get_base_data(base);
943         result->obj = delta_obj;
944         result->data = patch_delta(base_data, base->size,
945                                    delta_data, delta_obj->size, &result->size);
946         free(delta_data);
947         if (!result->data)
948                 bad_object(delta_obj->idx.offset, _("failed to apply delta"));
949         hash_sha1_file(result->data, result->size,
950                        typename(delta_obj->real_type), delta_obj->idx.sha1);
951         sha1_object(result->data, NULL, result->size, delta_obj->real_type,
952                     delta_obj->idx.sha1);
953         counter_lock();
954         nr_resolved_deltas++;
955         counter_unlock();
956 }
957
958 /*
959  * Standard boolean compare-and-swap: atomically check whether "*type" is
960  * "want"; if so, swap in "set" and return true. Otherwise, leave it untouched
961  * and return false.
962  */
963 static int compare_and_swap_type(signed char *type,
964                                  enum object_type want,
965                                  enum object_type set)
966 {
967         enum object_type old;
968
969         type_cas_lock();
970         old = *type;
971         if (old == want)
972                 *type = set;
973         type_cas_unlock();
974
975         return old == want;
976 }
977
978 static struct base_data *find_unresolved_deltas_1(struct base_data *base,
979                                                   struct base_data *prev_base)
980 {
981         if (base->ref_last == -1 && base->ofs_last == -1) {
982                 find_ref_delta_children(base->obj->idx.sha1,
983                                         &base->ref_first, &base->ref_last,
984                                         OBJ_REF_DELTA);
985
986                 find_ofs_delta_children(base->obj->idx.offset,
987                                         &base->ofs_first, &base->ofs_last,
988                                         OBJ_OFS_DELTA);
989
990                 if (base->ref_last == -1 && base->ofs_last == -1) {
991                         free(base->data);
992                         return NULL;
993                 }
994
995                 link_base_data(prev_base, base);
996         }
997
998         if (base->ref_first <= base->ref_last) {
999                 struct object_entry *child = objects + ref_deltas[base->ref_first].obj_no;
1000                 struct base_data *result = alloc_base_data();
1001
1002                 if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA,
1003                                            base->obj->real_type))
1004                         die("BUG: child->real_type != OBJ_REF_DELTA");
1005
1006                 resolve_delta(child, base, result);
1007                 if (base->ref_first == base->ref_last && base->ofs_last == -1)
1008                         free_base_data(base);
1009
1010                 base->ref_first++;
1011                 return result;
1012         }
1013
1014         if (base->ofs_first <= base->ofs_last) {
1015                 struct object_entry *child = objects + ofs_deltas[base->ofs_first].obj_no;
1016                 struct base_data *result = alloc_base_data();
1017
1018                 assert(child->real_type == OBJ_OFS_DELTA);
1019                 child->real_type = base->obj->real_type;
1020                 resolve_delta(child, base, result);
1021                 if (base->ofs_first == base->ofs_last)
1022                         free_base_data(base);
1023
1024                 base->ofs_first++;
1025                 return result;
1026         }
1027
1028         unlink_base_data(base);
1029         return NULL;
1030 }
1031
1032 static void find_unresolved_deltas(struct base_data *base)
1033 {
1034         struct base_data *new_base, *prev_base = NULL;
1035         for (;;) {
1036                 new_base = find_unresolved_deltas_1(base, prev_base);
1037
1038                 if (new_base) {
1039                         prev_base = base;
1040                         base = new_base;
1041                 } else {
1042                         free(base);
1043                         base = prev_base;
1044                         if (!base)
1045                                 return;
1046                         prev_base = base->base;
1047                 }
1048         }
1049 }
1050
1051 static int compare_ofs_delta_entry(const void *a, const void *b)
1052 {
1053         const struct ofs_delta_entry *delta_a = a;
1054         const struct ofs_delta_entry *delta_b = b;
1055
1056         return delta_a->offset < delta_b->offset ? -1 :
1057                delta_a->offset > delta_b->offset ?  1 :
1058                0;
1059 }
1060
1061 static int compare_ref_delta_entry(const void *a, const void *b)
1062 {
1063         const struct ref_delta_entry *delta_a = a;
1064         const struct ref_delta_entry *delta_b = b;
1065
1066         return hashcmp(delta_a->sha1, delta_b->sha1);
1067 }
1068
1069 static void resolve_base(struct object_entry *obj)
1070 {
1071         struct base_data *base_obj = alloc_base_data();
1072         base_obj->obj = obj;
1073         base_obj->data = NULL;
1074         find_unresolved_deltas(base_obj);
1075 }
1076
1077 #ifndef NO_PTHREADS
1078 static void *threaded_second_pass(void *data)
1079 {
1080         set_thread_data(data);
1081         for (;;) {
1082                 int i;
1083                 counter_lock();
1084                 display_progress(progress, nr_resolved_deltas);
1085                 counter_unlock();
1086                 work_lock();
1087                 while (nr_dispatched < nr_objects &&
1088                        is_delta_type(objects[nr_dispatched].type))
1089                         nr_dispatched++;
1090                 if (nr_dispatched >= nr_objects) {
1091                         work_unlock();
1092                         break;
1093                 }
1094                 i = nr_dispatched++;
1095                 work_unlock();
1096
1097                 resolve_base(&objects[i]);
1098         }
1099         return NULL;
1100 }
1101 #endif
1102
1103 /*
1104  * First pass:
1105  * - find locations of all objects;
1106  * - calculate SHA1 of all non-delta objects;
1107  * - remember base (SHA1 or offset) for all deltas.
1108  */
1109 static void parse_pack_objects(unsigned char *sha1)
1110 {
1111         int i, nr_delays = 0;
1112         struct ofs_delta_entry *ofs_delta = ofs_deltas;
1113         unsigned char ref_delta_sha1[20];
1114         struct stat st;
1115
1116         if (verbose)
1117                 progress = start_progress(
1118                                 from_stdin ? _("Receiving objects") : _("Indexing objects"),
1119                                 nr_objects);
1120         for (i = 0; i < nr_objects; i++) {
1121                 struct object_entry *obj = &objects[i];
1122                 void *data = unpack_raw_entry(obj, &ofs_delta->offset,
1123                                               ref_delta_sha1, obj->idx.sha1);
1124                 obj->real_type = obj->type;
1125                 if (obj->type == OBJ_OFS_DELTA) {
1126                         nr_ofs_deltas++;
1127                         ofs_delta->obj_no = i;
1128                         ofs_delta++;
1129                 } else if (obj->type == OBJ_REF_DELTA) {
1130                         ALLOC_GROW(ref_deltas, nr_ref_deltas + 1, ref_deltas_alloc);
1131                         hashcpy(ref_deltas[nr_ref_deltas].sha1, ref_delta_sha1);
1132                         ref_deltas[nr_ref_deltas].obj_no = i;
1133                         nr_ref_deltas++;
1134                 } else if (!data) {
1135                         /* large blobs, check later */
1136                         obj->real_type = OBJ_BAD;
1137                         nr_delays++;
1138                 } else
1139                         sha1_object(data, NULL, obj->size, obj->type, obj->idx.sha1);
1140                 free(data);
1141                 display_progress(progress, i+1);
1142         }
1143         objects[i].idx.offset = consumed_bytes;
1144         stop_progress(&progress);
1145
1146         /* Check pack integrity */
1147         flush();
1148         git_SHA1_Final(sha1, &input_ctx);
1149         if (hashcmp(fill(20), sha1))
1150                 die(_("pack is corrupted (SHA1 mismatch)"));
1151         use(20);
1152
1153         /* If input_fd is a file, we should have reached its end now. */
1154         if (fstat(input_fd, &st))
1155                 die_errno(_("cannot fstat packfile"));
1156         if (S_ISREG(st.st_mode) &&
1157                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
1158                 die(_("pack has junk at the end"));
1159
1160         for (i = 0; i < nr_objects; i++) {
1161                 struct object_entry *obj = &objects[i];
1162                 if (obj->real_type != OBJ_BAD)
1163                         continue;
1164                 obj->real_type = obj->type;
1165                 sha1_object(NULL, obj, obj->size, obj->type, obj->idx.sha1);
1166                 nr_delays--;
1167         }
1168         if (nr_delays)
1169                 die(_("confusion beyond insanity in parse_pack_objects()"));
1170 }
1171
1172 /*
1173  * Second pass:
1174  * - for all non-delta objects, look if it is used as a base for
1175  *   deltas;
1176  * - if used as a base, uncompress the object and apply all deltas,
1177  *   recursively checking if the resulting object is used as a base
1178  *   for some more deltas.
1179  */
1180 static void resolve_deltas(void)
1181 {
1182         int i;
1183
1184         if (!nr_ofs_deltas && !nr_ref_deltas)
1185                 return;
1186
1187         /* Sort deltas by base SHA1/offset for fast searching */
1188         qsort(ofs_deltas, nr_ofs_deltas, sizeof(struct ofs_delta_entry),
1189               compare_ofs_delta_entry);
1190         qsort(ref_deltas, nr_ref_deltas, sizeof(struct ref_delta_entry),
1191               compare_ref_delta_entry);
1192
1193         if (verbose)
1194                 progress = start_progress(_("Resolving deltas"),
1195                                           nr_ref_deltas + nr_ofs_deltas);
1196
1197 #ifndef NO_PTHREADS
1198         nr_dispatched = 0;
1199         if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) {
1200                 init_thread();
1201                 for (i = 0; i < nr_threads; i++) {
1202                         int ret = pthread_create(&thread_data[i].thread, NULL,
1203                                                  threaded_second_pass, thread_data + i);
1204                         if (ret)
1205                                 die(_("unable to create thread: %s"),
1206                                     strerror(ret));
1207                 }
1208                 for (i = 0; i < nr_threads; i++)
1209                         pthread_join(thread_data[i].thread, NULL);
1210                 cleanup_thread();
1211                 return;
1212         }
1213 #endif
1214
1215         for (i = 0; i < nr_objects; i++) {
1216                 struct object_entry *obj = &objects[i];
1217
1218                 if (is_delta_type(obj->type))
1219                         continue;
1220                 resolve_base(obj);
1221                 display_progress(progress, nr_resolved_deltas);
1222         }
1223 }
1224
1225 /*
1226  * Third pass:
1227  * - append objects to convert thin pack to full pack if required
1228  * - write the final 20-byte SHA-1
1229  */
1230 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved);
1231 static void conclude_pack(int fix_thin_pack, const char *curr_pack, unsigned char *pack_sha1)
1232 {
1233         if (nr_ref_deltas + nr_ofs_deltas == nr_resolved_deltas) {
1234                 stop_progress(&progress);
1235                 /* Flush remaining pack final 20-byte SHA1. */
1236                 flush();
1237                 return;
1238         }
1239
1240         if (fix_thin_pack) {
1241                 struct sha1file *f;
1242                 unsigned char read_sha1[20], tail_sha1[20];
1243                 struct strbuf msg = STRBUF_INIT;
1244                 int nr_unresolved = nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas;
1245                 int nr_objects_initial = nr_objects;
1246                 if (nr_unresolved <= 0)
1247                         die(_("confusion beyond insanity"));
1248                 REALLOC_ARRAY(objects, nr_objects + nr_unresolved + 1);
1249                 memset(objects + nr_objects + 1, 0,
1250                        nr_unresolved * sizeof(*objects));
1251                 f = sha1fd(output_fd, curr_pack);
1252                 fix_unresolved_deltas(f, nr_unresolved);
1253                 strbuf_addf(&msg, _("completed with %d local objects"),
1254                             nr_objects - nr_objects_initial);
1255                 stop_progress_msg(&progress, msg.buf);
1256                 strbuf_release(&msg);
1257                 sha1close(f, tail_sha1, 0);
1258                 hashcpy(read_sha1, pack_sha1);
1259                 fixup_pack_header_footer(output_fd, pack_sha1,
1260                                          curr_pack, nr_objects,
1261                                          read_sha1, consumed_bytes-20);
1262                 if (hashcmp(read_sha1, tail_sha1) != 0)
1263                         die(_("Unexpected tail checksum for %s "
1264                               "(disk corruption?)"), curr_pack);
1265         }
1266         if (nr_ofs_deltas + nr_ref_deltas != nr_resolved_deltas)
1267                 die(Q_("pack has %d unresolved delta",
1268                        "pack has %d unresolved deltas",
1269                        nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas),
1270                     nr_ofs_deltas + nr_ref_deltas - nr_resolved_deltas);
1271 }
1272
1273 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
1274 {
1275         git_zstream stream;
1276         int status;
1277         unsigned char outbuf[4096];
1278
1279         git_deflate_init(&stream, zlib_compression_level);
1280         stream.next_in = in;
1281         stream.avail_in = size;
1282
1283         do {
1284                 stream.next_out = outbuf;
1285                 stream.avail_out = sizeof(outbuf);
1286                 status = git_deflate(&stream, Z_FINISH);
1287                 sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
1288         } while (status == Z_OK);
1289
1290         if (status != Z_STREAM_END)
1291                 die(_("unable to deflate appended object (%d)"), status);
1292         size = stream.total_out;
1293         git_deflate_end(&stream);
1294         return size;
1295 }
1296
1297 static struct object_entry *append_obj_to_pack(struct sha1file *f,
1298                                const unsigned char *sha1, void *buf,
1299                                unsigned long size, enum object_type type)
1300 {
1301         struct object_entry *obj = &objects[nr_objects++];
1302         unsigned char header[10];
1303         unsigned long s = size;
1304         int n = 0;
1305         unsigned char c = (type << 4) | (s & 15);
1306         s >>= 4;
1307         while (s) {
1308                 header[n++] = c | 0x80;
1309                 c = s & 0x7f;
1310                 s >>= 7;
1311         }
1312         header[n++] = c;
1313         crc32_begin(f);
1314         sha1write(f, header, n);
1315         obj[0].size = size;
1316         obj[0].hdr_size = n;
1317         obj[0].type = type;
1318         obj[0].real_type = type;
1319         obj[1].idx.offset = obj[0].idx.offset + n;
1320         obj[1].idx.offset += write_compressed(f, buf, size);
1321         obj[0].idx.crc32 = crc32_end(f);
1322         sha1flush(f);
1323         hashcpy(obj->idx.sha1, sha1);
1324         return obj;
1325 }
1326
1327 static int delta_pos_compare(const void *_a, const void *_b)
1328 {
1329         struct ref_delta_entry *a = *(struct ref_delta_entry **)_a;
1330         struct ref_delta_entry *b = *(struct ref_delta_entry **)_b;
1331         return a->obj_no - b->obj_no;
1332 }
1333
1334 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
1335 {
1336         struct ref_delta_entry **sorted_by_pos;
1337         int i, n = 0;
1338
1339         /*
1340          * Since many unresolved deltas may well be themselves base objects
1341          * for more unresolved deltas, we really want to include the
1342          * smallest number of base objects that would cover as much delta
1343          * as possible by picking the
1344          * trunc deltas first, allowing for other deltas to resolve without
1345          * additional base objects.  Since most base objects are to be found
1346          * before deltas depending on them, a good heuristic is to start
1347          * resolving deltas in the same order as their position in the pack.
1348          */
1349         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
1350         for (i = 0; i < nr_ref_deltas; i++)
1351                 sorted_by_pos[n++] = &ref_deltas[i];
1352         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
1353
1354         for (i = 0; i < n; i++) {
1355                 struct ref_delta_entry *d = sorted_by_pos[i];
1356                 enum object_type type;
1357                 struct base_data *base_obj = alloc_base_data();
1358
1359                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
1360                         continue;
1361                 base_obj->data = read_sha1_file(d->sha1, &type, &base_obj->size);
1362                 if (!base_obj->data)
1363                         continue;
1364
1365                 if (check_sha1_signature(d->sha1, base_obj->data,
1366                                 base_obj->size, typename(type)))
1367                         die(_("local object %s is corrupt"), sha1_to_hex(d->sha1));
1368                 base_obj->obj = append_obj_to_pack(f, d->sha1,
1369                                         base_obj->data, base_obj->size, type);
1370                 find_unresolved_deltas(base_obj);
1371                 display_progress(progress, nr_resolved_deltas);
1372         }
1373         free(sorted_by_pos);
1374 }
1375
1376 static void final(const char *final_pack_name, const char *curr_pack_name,
1377                   const char *final_index_name, const char *curr_index_name,
1378                   const char *keep_name, const char *keep_msg,
1379                   unsigned char *sha1)
1380 {
1381         const char *report = "pack";
1382         char name[PATH_MAX];
1383         int err;
1384
1385         if (!from_stdin) {
1386                 close(input_fd);
1387         } else {
1388                 fsync_or_die(output_fd, curr_pack_name);
1389                 err = close(output_fd);
1390                 if (err)
1391                         die_errno(_("error while closing pack file"));
1392         }
1393
1394         if (keep_msg) {
1395                 int keep_fd, keep_msg_len = strlen(keep_msg);
1396
1397                 if (!keep_name)
1398                         keep_fd = odb_pack_keep(name, sizeof(name), sha1);
1399                 else
1400                         keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
1401
1402                 if (keep_fd < 0) {
1403                         if (errno != EEXIST)
1404                                 die_errno(_("cannot write keep file '%s'"),
1405                                           keep_name ? keep_name : name);
1406                 } else {
1407                         if (keep_msg_len > 0) {
1408                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
1409                                 write_or_die(keep_fd, "\n", 1);
1410                         }
1411                         if (close(keep_fd) != 0)
1412                                 die_errno(_("cannot close written keep file '%s'"),
1413                                           keep_name ? keep_name : name);
1414                         report = "keep";
1415                 }
1416         }
1417
1418         if (final_pack_name != curr_pack_name) {
1419                 if (!final_pack_name) {
1420                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
1421                                  get_object_directory(), sha1_to_hex(sha1));
1422                         final_pack_name = name;
1423                 }
1424                 if (move_temp_to_file(curr_pack_name, final_pack_name))
1425                         die(_("cannot store pack file"));
1426         } else if (from_stdin)
1427                 chmod(final_pack_name, 0444);
1428
1429         if (final_index_name != curr_index_name) {
1430                 if (!final_index_name) {
1431                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
1432                                  get_object_directory(), sha1_to_hex(sha1));
1433                         final_index_name = name;
1434                 }
1435                 if (move_temp_to_file(curr_index_name, final_index_name))
1436                         die(_("cannot store index file"));
1437         } else
1438                 chmod(final_index_name, 0444);
1439
1440         if (!from_stdin) {
1441                 printf("%s\n", sha1_to_hex(sha1));
1442         } else {
1443                 char buf[48];
1444                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
1445                                    report, sha1_to_hex(sha1));
1446                 write_or_die(1, buf, len);
1447
1448                 /*
1449                  * Let's just mimic git-unpack-objects here and write
1450                  * the last part of the input buffer to stdout.
1451                  */
1452                 while (input_len) {
1453                         err = xwrite(1, input_buffer + input_offset, input_len);
1454                         if (err <= 0)
1455                                 break;
1456                         input_len -= err;
1457                         input_offset += err;
1458                 }
1459         }
1460 }
1461
1462 static int git_index_pack_config(const char *k, const char *v, void *cb)
1463 {
1464         struct pack_idx_option *opts = cb;
1465
1466         if (!strcmp(k, "pack.indexversion")) {
1467                 opts->version = git_config_int(k, v);
1468                 if (opts->version > 2)
1469                         die(_("bad pack.indexversion=%"PRIu32), opts->version);
1470                 return 0;
1471         }
1472         if (!strcmp(k, "pack.threads")) {
1473                 nr_threads = git_config_int(k, v);
1474                 if (nr_threads < 0)
1475                         die(_("invalid number of threads specified (%d)"),
1476                             nr_threads);
1477 #ifdef NO_PTHREADS
1478                 if (nr_threads != 1)
1479                         warning(_("no threads support, ignoring %s"), k);
1480                 nr_threads = 1;
1481 #endif
1482                 return 0;
1483         }
1484         return git_default_config(k, v, cb);
1485 }
1486
1487 static int cmp_uint32(const void *a_, const void *b_)
1488 {
1489         uint32_t a = *((uint32_t *)a_);
1490         uint32_t b = *((uint32_t *)b_);
1491
1492         return (a < b) ? -1 : (a != b);
1493 }
1494
1495 static void read_v2_anomalous_offsets(struct packed_git *p,
1496                                       struct pack_idx_option *opts)
1497 {
1498         const uint32_t *idx1, *idx2;
1499         uint32_t i;
1500
1501         /* The address of the 4-byte offset table */
1502         idx1 = (((const uint32_t *)p->index_data)
1503                 + 2 /* 8-byte header */
1504                 + 256 /* fan out */
1505                 + 5 * p->num_objects /* 20-byte SHA-1 table */
1506                 + p->num_objects /* CRC32 table */
1507                 );
1508
1509         /* The address of the 8-byte offset table */
1510         idx2 = idx1 + p->num_objects;
1511
1512         for (i = 0; i < p->num_objects; i++) {
1513                 uint32_t off = ntohl(idx1[i]);
1514                 if (!(off & 0x80000000))
1515                         continue;
1516                 off = off & 0x7fffffff;
1517                 if (idx2[off * 2])
1518                         continue;
1519                 /*
1520                  * The real offset is ntohl(idx2[off * 2]) in high 4
1521                  * octets, and ntohl(idx2[off * 2 + 1]) in low 4
1522                  * octets.  But idx2[off * 2] is Zero!!!
1523                  */
1524                 ALLOC_GROW(opts->anomaly, opts->anomaly_nr + 1, opts->anomaly_alloc);
1525                 opts->anomaly[opts->anomaly_nr++] = ntohl(idx2[off * 2 + 1]);
1526         }
1527
1528         if (1 < opts->anomaly_nr)
1529                 qsort(opts->anomaly, opts->anomaly_nr, sizeof(uint32_t), cmp_uint32);
1530 }
1531
1532 static void read_idx_option(struct pack_idx_option *opts, const char *pack_name)
1533 {
1534         struct packed_git *p = add_packed_git(pack_name, strlen(pack_name), 1);
1535
1536         if (!p)
1537                 die(_("Cannot open existing pack file '%s'"), pack_name);
1538         if (open_pack_index(p))
1539                 die(_("Cannot open existing pack idx file for '%s'"), pack_name);
1540
1541         /* Read the attributes from the existing idx file */
1542         opts->version = p->index_version;
1543
1544         if (opts->version == 2)
1545                 read_v2_anomalous_offsets(p, opts);
1546
1547         /*
1548          * Get rid of the idx file as we do not need it anymore.
1549          * NEEDSWORK: extract this bit from free_pack_by_name() in
1550          * sha1_file.c, perhaps?  It shouldn't matter very much as we
1551          * know we haven't installed this pack (hence we never have
1552          * read anything from it).
1553          */
1554         close_pack_index(p);
1555         free(p);
1556 }
1557
1558 static void show_pack_info(int stat_only)
1559 {
1560         int i, baseobjects = nr_objects - nr_ref_deltas - nr_ofs_deltas;
1561         unsigned long *chain_histogram = NULL;
1562
1563         if (deepest_delta)
1564                 chain_histogram = xcalloc(deepest_delta, sizeof(unsigned long));
1565
1566         for (i = 0; i < nr_objects; i++) {
1567                 struct object_entry *obj = &objects[i];
1568
1569                 if (is_delta_type(obj->type))
1570                         chain_histogram[obj_stat[i].delta_depth - 1]++;
1571                 if (stat_only)
1572                         continue;
1573                 printf("%s %-6s %lu %lu %"PRIuMAX,
1574                        sha1_to_hex(obj->idx.sha1),
1575                        typename(obj->real_type), obj->size,
1576                        (unsigned long)(obj[1].idx.offset - obj->idx.offset),
1577                        (uintmax_t)obj->idx.offset);
1578                 if (is_delta_type(obj->type)) {
1579                         struct object_entry *bobj = &objects[obj_stat[i].base_object_no];
1580                         printf(" %u %s", obj_stat[i].delta_depth, sha1_to_hex(bobj->idx.sha1));
1581                 }
1582                 putchar('\n');
1583         }
1584
1585         if (baseobjects)
1586                 printf_ln(Q_("non delta: %d object",
1587                              "non delta: %d objects",
1588                              baseobjects),
1589                           baseobjects);
1590         for (i = 0; i < deepest_delta; i++) {
1591                 if (!chain_histogram[i])
1592                         continue;
1593                 printf_ln(Q_("chain length = %d: %lu object",
1594                              "chain length = %d: %lu objects",
1595                              chain_histogram[i]),
1596                           i + 1,
1597                           chain_histogram[i]);
1598         }
1599 }
1600
1601 int cmd_index_pack(int argc, const char **argv, const char *prefix)
1602 {
1603         int i, fix_thin_pack = 0, verify = 0, stat_only = 0;
1604         const char *curr_index;
1605         const char *index_name = NULL, *pack_name = NULL;
1606         const char *keep_name = NULL, *keep_msg = NULL;
1607         struct strbuf index_name_buf = STRBUF_INIT,
1608                       keep_name_buf = STRBUF_INIT;
1609         struct pack_idx_entry **idx_objects;
1610         struct pack_idx_option opts;
1611         unsigned char pack_sha1[20];
1612         unsigned foreign_nr = 1;        /* zero is a "good" value, assume bad */
1613
1614         if (argc == 2 && !strcmp(argv[1], "-h"))
1615                 usage(index_pack_usage);
1616
1617         check_replace_refs = 0;
1618
1619         reset_pack_idx_option(&opts);
1620         git_config(git_index_pack_config, &opts);
1621         if (prefix && chdir(prefix))
1622                 die(_("Cannot come back to cwd"));
1623
1624         for (i = 1; i < argc; i++) {
1625                 const char *arg = argv[i];
1626
1627                 if (*arg == '-') {
1628                         if (!strcmp(arg, "--stdin")) {
1629                                 from_stdin = 1;
1630                         } else if (!strcmp(arg, "--fix-thin")) {
1631                                 fix_thin_pack = 1;
1632                         } else if (!strcmp(arg, "--strict")) {
1633                                 strict = 1;
1634                                 do_fsck_object = 1;
1635                         } else if (!strcmp(arg, "--check-self-contained-and-connected")) {
1636                                 strict = 1;
1637                                 check_self_contained_and_connected = 1;
1638                         } else if (!strcmp(arg, "--verify")) {
1639                                 verify = 1;
1640                         } else if (!strcmp(arg, "--verify-stat")) {
1641                                 verify = 1;
1642                                 show_stat = 1;
1643                         } else if (!strcmp(arg, "--verify-stat-only")) {
1644                                 verify = 1;
1645                                 show_stat = 1;
1646                                 stat_only = 1;
1647                         } else if (!strcmp(arg, "--keep")) {
1648                                 keep_msg = "";
1649                         } else if (starts_with(arg, "--keep=")) {
1650                                 keep_msg = arg + 7;
1651                         } else if (starts_with(arg, "--threads=")) {
1652                                 char *end;
1653                                 nr_threads = strtoul(arg+10, &end, 0);
1654                                 if (!arg[10] || *end || nr_threads < 0)
1655                                         usage(index_pack_usage);
1656 #ifdef NO_PTHREADS
1657                                 if (nr_threads != 1)
1658                                         warning(_("no threads support, "
1659                                                   "ignoring %s"), arg);
1660                                 nr_threads = 1;
1661 #endif
1662                         } else if (starts_with(arg, "--pack_header=")) {
1663                                 struct pack_header *hdr;
1664                                 char *c;
1665
1666                                 hdr = (struct pack_header *)input_buffer;
1667                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
1668                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
1669                                 if (*c != ',')
1670                                         die(_("bad %s"), arg);
1671                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
1672                                 if (*c)
1673                                         die(_("bad %s"), arg);
1674                                 input_len = sizeof(*hdr);
1675                         } else if (!strcmp(arg, "-v")) {
1676                                 verbose = 1;
1677                         } else if (!strcmp(arg, "-o")) {
1678                                 if (index_name || (i+1) >= argc)
1679                                         usage(index_pack_usage);
1680                                 index_name = argv[++i];
1681                         } else if (starts_with(arg, "--index-version=")) {
1682                                 char *c;
1683                                 opts.version = strtoul(arg + 16, &c, 10);
1684                                 if (opts.version > 2)
1685                                         die(_("bad %s"), arg);
1686                                 if (*c == ',')
1687                                         opts.off32_limit = strtoul(c+1, &c, 0);
1688                                 if (*c || opts.off32_limit & 0x80000000)
1689                                         die(_("bad %s"), arg);
1690                         } else
1691                                 usage(index_pack_usage);
1692                         continue;
1693                 }
1694
1695                 if (pack_name)
1696                         usage(index_pack_usage);
1697                 pack_name = arg;
1698         }
1699
1700         if (!pack_name && !from_stdin)
1701                 usage(index_pack_usage);
1702         if (fix_thin_pack && !from_stdin)
1703                 die(_("--fix-thin cannot be used without --stdin"));
1704         if (!index_name && pack_name) {
1705                 size_t len;
1706                 if (!strip_suffix(pack_name, ".pack", &len))
1707                         die(_("packfile name '%s' does not end with '.pack'"),
1708                             pack_name);
1709                 strbuf_add(&index_name_buf, pack_name, len);
1710                 strbuf_addstr(&index_name_buf, ".idx");
1711                 index_name = index_name_buf.buf;
1712         }
1713         if (keep_msg && !keep_name && pack_name) {
1714                 size_t len;
1715                 if (!strip_suffix(pack_name, ".pack", &len))
1716                         die(_("packfile name '%s' does not end with '.pack'"),
1717                             pack_name);
1718                 strbuf_add(&keep_name_buf, pack_name, len);
1719                 strbuf_addstr(&keep_name_buf, ".idx");
1720                 keep_name = keep_name_buf.buf;
1721         }
1722         if (verify) {
1723                 if (!index_name)
1724                         die(_("--verify with no packfile name given"));
1725                 read_idx_option(&opts, index_name);
1726                 opts.flags |= WRITE_IDX_VERIFY | WRITE_IDX_STRICT;
1727         }
1728         if (strict)
1729                 opts.flags |= WRITE_IDX_STRICT;
1730
1731 #ifndef NO_PTHREADS
1732         if (!nr_threads) {
1733                 nr_threads = online_cpus();
1734                 /* An experiment showed that more threads does not mean faster */
1735                 if (nr_threads > 3)
1736                         nr_threads = 3;
1737         }
1738 #endif
1739
1740         curr_pack = open_pack_file(pack_name);
1741         parse_pack_header();
1742         objects = xcalloc(nr_objects + 1, sizeof(struct object_entry));
1743         if (show_stat)
1744                 obj_stat = xcalloc(nr_objects + 1, sizeof(struct object_stat));
1745         ofs_deltas = xcalloc(nr_objects, sizeof(struct ofs_delta_entry));
1746         parse_pack_objects(pack_sha1);
1747         resolve_deltas();
1748         conclude_pack(fix_thin_pack, curr_pack, pack_sha1);
1749         free(ofs_deltas);
1750         free(ref_deltas);
1751         if (strict)
1752                 foreign_nr = check_objects();
1753
1754         if (show_stat)
1755                 show_pack_info(stat_only);
1756
1757         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1758         for (i = 0; i < nr_objects; i++)
1759                 idx_objects[i] = &objects[i].idx;
1760         curr_index = write_idx_file(index_name, idx_objects, nr_objects, &opts, pack_sha1);
1761         free(idx_objects);
1762
1763         if (!verify)
1764                 final(pack_name, curr_pack,
1765                       index_name, curr_index,
1766                       keep_name, keep_msg,
1767                       pack_sha1);
1768         else
1769                 close(input_fd);
1770         free(objects);
1771         strbuf_release(&index_name_buf);
1772         strbuf_release(&keep_name_buf);
1773         if (pack_name == NULL)
1774                 free((void *) curr_pack);
1775         if (index_name == NULL)
1776                 free((void *) curr_index);
1777
1778         /*
1779          * Let the caller know this pack is not self contained
1780          */
1781         if (check_self_contained_and_connected && foreign_nr)
1782                 return 1;
1783
1784         return 0;
1785 }