Merge branch 'maint'
[git] / builtin-pack-objects.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "object.h"
4 #include "blob.h"
5 #include "commit.h"
6 #include "tag.h"
7 #include "tree.h"
8 #include "delta.h"
9 #include "pack.h"
10 #include "csum-file.h"
11 #include "tree-walk.h"
12 #include "diff.h"
13 #include "revision.h"
14 #include "list-objects.h"
15 #include <sys/time.h>
16 #include <signal.h>
17
18 static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--delta-base-offset] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] [--all-progress] [--revs [--unpacked | --all]*] [--stdout | base-name] <ref-list | <object-list]";
19
20 struct object_entry {
21         unsigned char sha1[20];
22         unsigned long size;     /* uncompressed size */
23         unsigned long offset;   /* offset into the final pack file;
24                                  * nonzero if already written.
25                                  */
26         unsigned int depth;     /* delta depth */
27         unsigned int delta_limit;       /* base adjustment for in-pack delta */
28         unsigned int hash;      /* name hint hash */
29         enum object_type type;
30         enum object_type in_pack_type;  /* could be delta */
31         unsigned long delta_size;       /* delta data size (uncompressed) */
32 #define in_pack_header_size delta_size  /* only when reusing pack data */
33         struct object_entry *delta;     /* delta base object */
34         struct packed_git *in_pack;     /* already in pack */
35         unsigned int in_pack_offset;
36         struct object_entry *delta_child; /* deltified objects who bases me */
37         struct object_entry *delta_sibling; /* other deltified objects who
38                                              * uses the same base as me
39                                              */
40         int preferred_base;     /* we do not pack this, but is encouraged to
41                                  * be used as the base objectto delta huge
42                                  * objects against.
43                                  */
44 };
45
46 /*
47  * Objects we are going to pack are collected in objects array (dynamically
48  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
49  * in the order we see -- typically rev-list --objects order that gives us
50  * nice "minimum seek" order.
51  *
52  * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
53  * elements in the objects array.  The former is used to build the pack
54  * index (lists object names in the ascending order to help offset lookup),
55  * and the latter is used to group similar things together by try_delta()
56  * heuristics.
57  */
58
59 static unsigned char object_list_sha1[20];
60 static int non_empty;
61 static int no_reuse_delta;
62 static int local;
63 static int incremental;
64 static int allow_ofs_delta;
65
66 static struct object_entry **sorted_by_sha, **sorted_by_type;
67 static struct object_entry *objects;
68 static int nr_objects, nr_alloc, nr_result;
69 static const char *base_name;
70 static unsigned char pack_file_sha1[20];
71 static int progress = 1;
72 static volatile sig_atomic_t progress_update;
73 static int window = 10;
74 static int pack_to_stdout;
75 static int num_preferred_base;
76
77 /*
78  * The object names in objects array are hashed with this hashtable,
79  * to help looking up the entry by object name.  Binary search from
80  * sorted_by_sha is also possible but this was easier to code and faster.
81  * This hashtable is built after all the objects are seen.
82  */
83 static int *object_ix;
84 static int object_ix_hashsz;
85
86 /*
87  * Pack index for existing packs give us easy access to the offsets into
88  * corresponding pack file where each object's data starts, but the entries
89  * do not store the size of the compressed representation (uncompressed
90  * size is easily available by examining the pack entry header).  It is
91  * also rather expensive to find the sha1 for an object given its offset.
92  *
93  * We build a hashtable of existing packs (pack_revindex), and keep reverse
94  * index here -- pack index file is sorted by object name mapping to offset;
95  * this pack_revindex[].revindex array is a list of offset/index_nr pairs
96  * ordered by offset, so if you know the offset of an object, next offset
97  * is where its packed representation ends and the index_nr can be used to
98  * get the object sha1 from the main index.
99  */
100 struct revindex_entry {
101         unsigned int offset;
102         unsigned int nr;
103 };
104 struct pack_revindex {
105         struct packed_git *p;
106         struct revindex_entry *revindex;
107 };
108 static struct  pack_revindex *pack_revindex;
109 static int pack_revindex_hashsz;
110
111 /*
112  * stats
113  */
114 static int written;
115 static int written_delta;
116 static int reused;
117 static int reused_delta;
118
119 static int pack_revindex_ix(struct packed_git *p)
120 {
121         unsigned long ui = (unsigned long)p;
122         int i;
123
124         ui = ui ^ (ui >> 16); /* defeat structure alignment */
125         i = (int)(ui % pack_revindex_hashsz);
126         while (pack_revindex[i].p) {
127                 if (pack_revindex[i].p == p)
128                         return i;
129                 if (++i == pack_revindex_hashsz)
130                         i = 0;
131         }
132         return -1 - i;
133 }
134
135 static void prepare_pack_ix(void)
136 {
137         int num;
138         struct packed_git *p;
139         for (num = 0, p = packed_git; p; p = p->next)
140                 num++;
141         if (!num)
142                 return;
143         pack_revindex_hashsz = num * 11;
144         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
145         for (p = packed_git; p; p = p->next) {
146                 num = pack_revindex_ix(p);
147                 num = - 1 - num;
148                 pack_revindex[num].p = p;
149         }
150         /* revindex elements are lazily initialized */
151 }
152
153 static int cmp_offset(const void *a_, const void *b_)
154 {
155         const struct revindex_entry *a = a_;
156         const struct revindex_entry *b = b_;
157         return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
158 }
159
160 /*
161  * Ordered list of offsets of objects in the pack.
162  */
163 static void prepare_pack_revindex(struct pack_revindex *rix)
164 {
165         struct packed_git *p = rix->p;
166         int num_ent = num_packed_objects(p);
167         int i;
168         void *index = p->index_base + 256;
169
170         rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
171         for (i = 0; i < num_ent; i++) {
172                 unsigned int hl = *((unsigned int *)((char *) index + 24*i));
173                 rix->revindex[i].offset = ntohl(hl);
174                 rix->revindex[i].nr = i;
175         }
176         /* This knows the pack format -- the 20-byte trailer
177          * follows immediately after the last object data.
178          */
179         rix->revindex[num_ent].offset = p->pack_size - 20;
180         rix->revindex[num_ent].nr = -1;
181         qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
182 }
183
184 static struct revindex_entry * find_packed_object(struct packed_git *p,
185                                                   unsigned int ofs)
186 {
187         int num;
188         int lo, hi;
189         struct pack_revindex *rix;
190         struct revindex_entry *revindex;
191         num = pack_revindex_ix(p);
192         if (num < 0)
193                 die("internal error: pack revindex uninitialized");
194         rix = &pack_revindex[num];
195         if (!rix->revindex)
196                 prepare_pack_revindex(rix);
197         revindex = rix->revindex;
198         lo = 0;
199         hi = num_packed_objects(p) + 1;
200         do {
201                 int mi = (lo + hi) / 2;
202                 if (revindex[mi].offset == ofs) {
203                         return revindex + mi;
204                 }
205                 else if (ofs < revindex[mi].offset)
206                         hi = mi;
207                 else
208                         lo = mi + 1;
209         } while (lo < hi);
210         die("internal error: pack revindex corrupt");
211 }
212
213 static unsigned long find_packed_object_size(struct packed_git *p,
214                                              unsigned long ofs)
215 {
216         struct revindex_entry *entry = find_packed_object(p, ofs);
217         return entry[1].offset - ofs;
218 }
219
220 static unsigned char *find_packed_object_name(struct packed_git *p,
221                                               unsigned long ofs)
222 {
223         struct revindex_entry *entry = find_packed_object(p, ofs);
224         return (unsigned char *)(p->index_base + 256) + 24 * entry->nr + 4;
225 }
226
227 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
228 {
229         unsigned long othersize, delta_size;
230         char type[10];
231         void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize);
232         void *delta_buf;
233
234         if (!otherbuf)
235                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
236         delta_buf = diff_delta(otherbuf, othersize,
237                                buf, size, &delta_size, 0);
238         if (!delta_buf || delta_size != entry->delta_size)
239                 die("delta size changed");
240         free(buf);
241         free(otherbuf);
242         return delta_buf;
243 }
244
245 /*
246  * The per-object header is a pretty dense thing, which is
247  *  - first byte: low four bits are "size", then three bits of "type",
248  *    and the high bit is "size continues".
249  *  - each byte afterwards: low seven bits are size continuation,
250  *    with the high bit being "size continues"
251  */
252 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
253 {
254         int n = 1;
255         unsigned char c;
256
257         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
258                 die("bad type %d", type);
259
260         c = (type << 4) | (size & 15);
261         size >>= 4;
262         while (size) {
263                 *hdr++ = c | 0x80;
264                 c = size & 0x7f;
265                 size >>= 7;
266                 n++;
267         }
268         *hdr = c;
269         return n;
270 }
271
272 /*
273  * we are going to reuse the existing object data as is.  make
274  * sure it is not corrupt.
275  */
276 static int check_inflate(unsigned char *data, unsigned long len, unsigned long expect)
277 {
278         z_stream stream;
279         unsigned char fakebuf[4096];
280         int st;
281
282         memset(&stream, 0, sizeof(stream));
283         stream.next_in = data;
284         stream.avail_in = len;
285         stream.next_out = fakebuf;
286         stream.avail_out = sizeof(fakebuf);
287         inflateInit(&stream);
288
289         while (1) {
290                 st = inflate(&stream, Z_FINISH);
291                 if (st == Z_STREAM_END || st == Z_OK) {
292                         st = (stream.total_out == expect &&
293                               stream.total_in == len) ? 0 : -1;
294                         break;
295                 }
296                 if (st != Z_BUF_ERROR) {
297                         st = -1;
298                         break;
299                 }
300                 stream.next_out = fakebuf;
301                 stream.avail_out = sizeof(fakebuf);
302         }
303         inflateEnd(&stream);
304         return st;
305 }
306
307 static int revalidate_loose_object(struct object_entry *entry,
308                                    unsigned char *map,
309                                    unsigned long mapsize)
310 {
311         /* we already know this is a loose object with new type header. */
312         enum object_type type;
313         unsigned long size, used;
314
315         if (pack_to_stdout)
316                 return 0;
317
318         used = unpack_object_header_gently(map, mapsize, &type, &size);
319         if (!used)
320                 return -1;
321         map += used;
322         mapsize -= used;
323         return check_inflate(map, mapsize, size);
324 }
325
326 static unsigned long write_object(struct sha1file *f,
327                                   struct object_entry *entry)
328 {
329         unsigned long size;
330         char type[10];
331         void *buf;
332         unsigned char header[10];
333         unsigned hdrlen, datalen;
334         enum object_type obj_type;
335         int to_reuse = 0;
336
337         obj_type = entry->type;
338         if (! entry->in_pack)
339                 to_reuse = 0;   /* can't reuse what we don't have */
340         else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
341                 to_reuse = 1;   /* check_object() decided it for us */
342         else if (obj_type != entry->in_pack_type)
343                 to_reuse = 0;   /* pack has delta which is unusable */
344         else if (entry->delta)
345                 to_reuse = 0;   /* we want to pack afresh */
346         else
347                 to_reuse = 1;   /* we have it in-pack undeltified,
348                                  * and we do not need to deltify it.
349                                  */
350
351         if (!entry->in_pack && !entry->delta) {
352                 unsigned char *map;
353                 unsigned long mapsize;
354                 map = map_sha1_file(entry->sha1, &mapsize);
355                 if (map && !legacy_loose_object(map)) {
356                         /* We can copy straight into the pack file */
357                         if (revalidate_loose_object(entry, map, mapsize))
358                                 die("corrupt loose object %s",
359                                     sha1_to_hex(entry->sha1));
360                         sha1write(f, map, mapsize);
361                         munmap(map, mapsize);
362                         written++;
363                         reused++;
364                         return mapsize;
365                 }
366                 if (map)
367                         munmap(map, mapsize);
368         }
369
370         if (!to_reuse) {
371                 buf = read_sha1_file(entry->sha1, type, &size);
372                 if (!buf)
373                         die("unable to read %s", sha1_to_hex(entry->sha1));
374                 if (size != entry->size)
375                         die("object %s size inconsistency (%lu vs %lu)",
376                             sha1_to_hex(entry->sha1), size, entry->size);
377                 if (entry->delta) {
378                         buf = delta_against(buf, size, entry);
379                         size = entry->delta_size;
380                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
381                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
382                 }
383                 /*
384                  * The object header is a byte of 'type' followed by zero or
385                  * more bytes of length.
386                  */
387                 hdrlen = encode_header(obj_type, size, header);
388                 sha1write(f, header, hdrlen);
389
390                 if (obj_type == OBJ_OFS_DELTA) {
391                         /*
392                          * Deltas with relative base contain an additional
393                          * encoding of the relative offset for the delta
394                          * base from this object's position in the pack.
395                          */
396                         unsigned long ofs = entry->offset - entry->delta->offset;
397                         unsigned pos = sizeof(header) - 1;
398                         header[pos] = ofs & 127;
399                         while (ofs >>= 7)
400                                 header[--pos] = 128 | (--ofs & 127);
401                         sha1write(f, header + pos, sizeof(header) - pos);
402                         hdrlen += sizeof(header) - pos;
403                 } else if (obj_type == OBJ_REF_DELTA) {
404                         /*
405                          * Deltas with a base reference contain
406                          * an additional 20 bytes for the base sha1.
407                          */
408                         sha1write(f, entry->delta->sha1, 20);
409                         hdrlen += 20;
410                 }
411                 datalen = sha1write_compressed(f, buf, size);
412                 free(buf);
413         }
414         else {
415                 struct packed_git *p = entry->in_pack;
416
417                 if (entry->delta) {
418                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
419                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
420                         reused_delta++;
421                 }
422                 hdrlen = encode_header(obj_type, entry->size, header);
423                 sha1write(f, header, hdrlen);
424                 if (obj_type == OBJ_OFS_DELTA) {
425                         unsigned long ofs = entry->offset - entry->delta->offset;
426                         unsigned pos = sizeof(header) - 1;
427                         header[pos] = ofs & 127;
428                         while (ofs >>= 7)
429                                 header[--pos] = 128 | (--ofs & 127);
430                         sha1write(f, header + pos, sizeof(header) - pos);
431                         hdrlen += sizeof(header) - pos;
432                 } else if (obj_type == OBJ_REF_DELTA) {
433                         sha1write(f, entry->delta->sha1, 20);
434                         hdrlen += 20;
435                 }
436
437                 use_packed_git(p);
438                 buf = (char *) p->pack_base
439                         + entry->in_pack_offset
440                         + entry->in_pack_header_size;
441                 datalen = find_packed_object_size(p, entry->in_pack_offset)
442                                 - entry->in_pack_header_size;
443                 if (!pack_to_stdout && check_inflate(buf, datalen, entry->size))
444                         die("corrupt delta in pack %s", sha1_to_hex(entry->sha1));
445                 sha1write(f, buf, datalen);
446                 unuse_packed_git(p);
447                 reused++;
448         }
449         if (entry->delta)
450                 written_delta++;
451         written++;
452         return hdrlen + datalen;
453 }
454
455 static unsigned long write_one(struct sha1file *f,
456                                struct object_entry *e,
457                                unsigned long offset)
458 {
459         if (e->offset || e->preferred_base)
460                 /* offset starts from header size and cannot be zero
461                  * if it is written already.
462                  */
463                 return offset;
464         /* if we are deltified, write out its base object first. */
465         if (e->delta)
466                 offset = write_one(f, e->delta, offset);
467         e->offset = offset;
468         return offset + write_object(f, e);
469 }
470
471 static void write_pack_file(void)
472 {
473         int i;
474         struct sha1file *f;
475         unsigned long offset;
476         struct pack_header hdr;
477         unsigned last_percent = 999;
478         int do_progress = progress;
479
480         if (!base_name) {
481                 f = sha1fd(1, "<stdout>");
482                 do_progress >>= 1;
483         }
484         else
485                 f = sha1create("%s-%s.%s", base_name,
486                                sha1_to_hex(object_list_sha1), "pack");
487         if (do_progress)
488                 fprintf(stderr, "Writing %d objects.\n", nr_result);
489
490         hdr.hdr_signature = htonl(PACK_SIGNATURE);
491         hdr.hdr_version = htonl(PACK_VERSION);
492         hdr.hdr_entries = htonl(nr_result);
493         sha1write(f, &hdr, sizeof(hdr));
494         offset = sizeof(hdr);
495         if (!nr_result)
496                 goto done;
497         for (i = 0; i < nr_objects; i++) {
498                 offset = write_one(f, objects + i, offset);
499                 if (do_progress) {
500                         unsigned percent = written * 100 / nr_result;
501                         if (progress_update || percent != last_percent) {
502                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
503                                         percent, written, nr_result);
504                                 progress_update = 0;
505                                 last_percent = percent;
506                         }
507                 }
508         }
509         if (do_progress)
510                 fputc('\n', stderr);
511  done:
512         sha1close(f, pack_file_sha1, 1);
513 }
514
515 static void write_index_file(void)
516 {
517         int i;
518         struct sha1file *f = sha1create("%s-%s.%s", base_name,
519                                         sha1_to_hex(object_list_sha1), "idx");
520         struct object_entry **list = sorted_by_sha;
521         struct object_entry **last = list + nr_result;
522         unsigned int array[256];
523
524         /*
525          * Write the first-level table (the list is sorted,
526          * but we use a 256-entry lookup to be able to avoid
527          * having to do eight extra binary search iterations).
528          */
529         for (i = 0; i < 256; i++) {
530                 struct object_entry **next = list;
531                 while (next < last) {
532                         struct object_entry *entry = *next;
533                         if (entry->sha1[0] != i)
534                                 break;
535                         next++;
536                 }
537                 array[i] = htonl(next - sorted_by_sha);
538                 list = next;
539         }
540         sha1write(f, array, 256 * sizeof(int));
541
542         /*
543          * Write the actual SHA1 entries..
544          */
545         list = sorted_by_sha;
546         for (i = 0; i < nr_result; i++) {
547                 struct object_entry *entry = *list++;
548                 unsigned int offset = htonl(entry->offset);
549                 sha1write(f, &offset, 4);
550                 sha1write(f, entry->sha1, 20);
551         }
552         sha1write(f, pack_file_sha1, 20);
553         sha1close(f, NULL, 1);
554 }
555
556 static int locate_object_entry_hash(const unsigned char *sha1)
557 {
558         int i;
559         unsigned int ui;
560         memcpy(&ui, sha1, sizeof(unsigned int));
561         i = ui % object_ix_hashsz;
562         while (0 < object_ix[i]) {
563                 if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
564                         return i;
565                 if (++i == object_ix_hashsz)
566                         i = 0;
567         }
568         return -1 - i;
569 }
570
571 static struct object_entry *locate_object_entry(const unsigned char *sha1)
572 {
573         int i;
574
575         if (!object_ix_hashsz)
576                 return NULL;
577
578         i = locate_object_entry_hash(sha1);
579         if (0 <= i)
580                 return &objects[object_ix[i]-1];
581         return NULL;
582 }
583
584 static void rehash_objects(void)
585 {
586         int i;
587         struct object_entry *oe;
588
589         object_ix_hashsz = nr_objects * 3;
590         if (object_ix_hashsz < 1024)
591                 object_ix_hashsz = 1024;
592         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
593         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
594         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
595                 int ix = locate_object_entry_hash(oe->sha1);
596                 if (0 <= ix)
597                         continue;
598                 ix = -1 - ix;
599                 object_ix[ix] = i + 1;
600         }
601 }
602
603 static unsigned name_hash(const char *name)
604 {
605         unsigned char c;
606         unsigned hash = 0;
607
608         /*
609          * This effectively just creates a sortable number from the
610          * last sixteen non-whitespace characters. Last characters
611          * count "most", so things that end in ".c" sort together.
612          */
613         while ((c = *name++) != 0) {
614                 if (isspace(c))
615                         continue;
616                 hash = (hash >> 2) + (c << 24);
617         }
618         return hash;
619 }
620
621 static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
622 {
623         unsigned int idx = nr_objects;
624         struct object_entry *entry;
625         struct packed_git *p;
626         unsigned int found_offset = 0;
627         struct packed_git *found_pack = NULL;
628         int ix, status = 0;
629
630         if (!exclude) {
631                 for (p = packed_git; p; p = p->next) {
632                         unsigned long offset = find_pack_entry_one(sha1, p);
633                         if (offset) {
634                                 if (incremental)
635                                         return 0;
636                                 if (local && !p->pack_local)
637                                         return 0;
638                                 if (!found_pack) {
639                                         found_offset = offset;
640                                         found_pack = p;
641                                 }
642                         }
643                 }
644         }
645         if ((entry = locate_object_entry(sha1)) != NULL)
646                 goto already_added;
647
648         if (idx >= nr_alloc) {
649                 unsigned int needed = (idx + 1024) * 3 / 2;
650                 objects = xrealloc(objects, needed * sizeof(*entry));
651                 nr_alloc = needed;
652         }
653         entry = objects + idx;
654         nr_objects = idx + 1;
655         memset(entry, 0, sizeof(*entry));
656         hashcpy(entry->sha1, sha1);
657         entry->hash = hash;
658
659         if (object_ix_hashsz * 3 <= nr_objects * 4)
660                 rehash_objects();
661         else {
662                 ix = locate_object_entry_hash(entry->sha1);
663                 if (0 <= ix)
664                         die("internal error in object hashing.");
665                 object_ix[-1 - ix] = idx + 1;
666         }
667         status = 1;
668
669  already_added:
670         if (progress_update) {
671                 fprintf(stderr, "Counting objects...%d\r", nr_objects);
672                 progress_update = 0;
673         }
674         if (exclude)
675                 entry->preferred_base = 1;
676         else {
677                 if (found_pack) {
678                         entry->in_pack = found_pack;
679                         entry->in_pack_offset = found_offset;
680                 }
681         }
682         return status;
683 }
684
685 struct pbase_tree_cache {
686         unsigned char sha1[20];
687         int ref;
688         int temporary;
689         void *tree_data;
690         unsigned long tree_size;
691 };
692
693 static struct pbase_tree_cache *(pbase_tree_cache[256]);
694 static int pbase_tree_cache_ix(const unsigned char *sha1)
695 {
696         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
697 }
698 static int pbase_tree_cache_ix_incr(int ix)
699 {
700         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
701 }
702
703 static struct pbase_tree {
704         struct pbase_tree *next;
705         /* This is a phony "cache" entry; we are not
706          * going to evict it nor find it through _get()
707          * mechanism -- this is for the toplevel node that
708          * would almost always change with any commit.
709          */
710         struct pbase_tree_cache pcache;
711 } *pbase_tree;
712
713 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
714 {
715         struct pbase_tree_cache *ent, *nent;
716         void *data;
717         unsigned long size;
718         char type[20];
719         int neigh;
720         int my_ix = pbase_tree_cache_ix(sha1);
721         int available_ix = -1;
722
723         /* pbase-tree-cache acts as a limited hashtable.
724          * your object will be found at your index or within a few
725          * slots after that slot if it is cached.
726          */
727         for (neigh = 0; neigh < 8; neigh++) {
728                 ent = pbase_tree_cache[my_ix];
729                 if (ent && !hashcmp(ent->sha1, sha1)) {
730                         ent->ref++;
731                         return ent;
732                 }
733                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
734                          ((0 <= available_ix) &&
735                           (!ent && pbase_tree_cache[available_ix])))
736                         available_ix = my_ix;
737                 if (!ent)
738                         break;
739                 my_ix = pbase_tree_cache_ix_incr(my_ix);
740         }
741
742         /* Did not find one.  Either we got a bogus request or
743          * we need to read and perhaps cache.
744          */
745         data = read_sha1_file(sha1, type, &size);
746         if (!data)
747                 return NULL;
748         if (strcmp(type, tree_type)) {
749                 free(data);
750                 return NULL;
751         }
752
753         /* We need to either cache or return a throwaway copy */
754
755         if (available_ix < 0)
756                 ent = NULL;
757         else {
758                 ent = pbase_tree_cache[available_ix];
759                 my_ix = available_ix;
760         }
761
762         if (!ent) {
763                 nent = xmalloc(sizeof(*nent));
764                 nent->temporary = (available_ix < 0);
765         }
766         else {
767                 /* evict and reuse */
768                 free(ent->tree_data);
769                 nent = ent;
770         }
771         hashcpy(nent->sha1, sha1);
772         nent->tree_data = data;
773         nent->tree_size = size;
774         nent->ref = 1;
775         if (!nent->temporary)
776                 pbase_tree_cache[my_ix] = nent;
777         return nent;
778 }
779
780 static void pbase_tree_put(struct pbase_tree_cache *cache)
781 {
782         if (!cache->temporary) {
783                 cache->ref--;
784                 return;
785         }
786         free(cache->tree_data);
787         free(cache);
788 }
789
790 static int name_cmp_len(const char *name)
791 {
792         int i;
793         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
794                 ;
795         return i;
796 }
797
798 static void add_pbase_object(struct tree_desc *tree,
799                              const char *name,
800                              int cmplen,
801                              const char *fullname)
802 {
803         struct name_entry entry;
804
805         while (tree_entry(tree,&entry)) {
806                 unsigned long size;
807                 char type[20];
808
809                 if (entry.pathlen != cmplen ||
810                     memcmp(entry.path, name, cmplen) ||
811                     !has_sha1_file(entry.sha1) ||
812                     sha1_object_info(entry.sha1, type, &size))
813                         continue;
814                 if (name[cmplen] != '/') {
815                         unsigned hash = name_hash(fullname);
816                         add_object_entry(entry.sha1, hash, 1);
817                         return;
818                 }
819                 if (!strcmp(type, tree_type)) {
820                         struct tree_desc sub;
821                         struct pbase_tree_cache *tree;
822                         const char *down = name+cmplen+1;
823                         int downlen = name_cmp_len(down);
824
825                         tree = pbase_tree_get(entry.sha1);
826                         if (!tree)
827                                 return;
828                         sub.buf = tree->tree_data;
829                         sub.size = tree->tree_size;
830
831                         add_pbase_object(&sub, down, downlen, fullname);
832                         pbase_tree_put(tree);
833                 }
834         }
835 }
836
837 static unsigned *done_pbase_paths;
838 static int done_pbase_paths_num;
839 static int done_pbase_paths_alloc;
840 static int done_pbase_path_pos(unsigned hash)
841 {
842         int lo = 0;
843         int hi = done_pbase_paths_num;
844         while (lo < hi) {
845                 int mi = (hi + lo) / 2;
846                 if (done_pbase_paths[mi] == hash)
847                         return mi;
848                 if (done_pbase_paths[mi] < hash)
849                         hi = mi;
850                 else
851                         lo = mi + 1;
852         }
853         return -lo-1;
854 }
855
856 static int check_pbase_path(unsigned hash)
857 {
858         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
859         if (0 <= pos)
860                 return 1;
861         pos = -pos - 1;
862         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
863                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
864                 done_pbase_paths = xrealloc(done_pbase_paths,
865                                             done_pbase_paths_alloc *
866                                             sizeof(unsigned));
867         }
868         done_pbase_paths_num++;
869         if (pos < done_pbase_paths_num)
870                 memmove(done_pbase_paths + pos + 1,
871                         done_pbase_paths + pos,
872                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
873         done_pbase_paths[pos] = hash;
874         return 0;
875 }
876
877 static void add_preferred_base_object(const char *name, unsigned hash)
878 {
879         struct pbase_tree *it;
880         int cmplen = name_cmp_len(name);
881
882         if (check_pbase_path(hash))
883                 return;
884
885         for (it = pbase_tree; it; it = it->next) {
886                 if (cmplen == 0) {
887                         hash = name_hash("");
888                         add_object_entry(it->pcache.sha1, hash, 1);
889                 }
890                 else {
891                         struct tree_desc tree;
892                         tree.buf = it->pcache.tree_data;
893                         tree.size = it->pcache.tree_size;
894                         add_pbase_object(&tree, name, cmplen, name);
895                 }
896         }
897 }
898
899 static void add_preferred_base(unsigned char *sha1)
900 {
901         struct pbase_tree *it;
902         void *data;
903         unsigned long size;
904         unsigned char tree_sha1[20];
905
906         if (window <= num_preferred_base++)
907                 return;
908
909         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
910         if (!data)
911                 return;
912
913         for (it = pbase_tree; it; it = it->next) {
914                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
915                         free(data);
916                         return;
917                 }
918         }
919
920         it = xcalloc(1, sizeof(*it));
921         it->next = pbase_tree;
922         pbase_tree = it;
923
924         hashcpy(it->pcache.sha1, tree_sha1);
925         it->pcache.tree_data = data;
926         it->pcache.tree_size = size;
927 }
928
929 static void check_object(struct object_entry *entry)
930 {
931         char type[20];
932
933         if (entry->in_pack && !entry->preferred_base) {
934                 struct packed_git *p = entry->in_pack;
935                 unsigned long left = p->pack_size - entry->in_pack_offset;
936                 unsigned long size, used;
937                 unsigned char *buf;
938                 struct object_entry *base_entry = NULL;
939
940                 use_packed_git(p);
941                 buf = p->pack_base;
942                 buf += entry->in_pack_offset;
943
944                 /* We want in_pack_type even if we do not reuse delta.
945                  * There is no point not reusing non-delta representations.
946                  */
947                 used = unpack_object_header_gently(buf, left,
948                                                    &entry->in_pack_type, &size);
949                 if (!used || left - used <= 20)
950                         die("corrupt pack for %s", sha1_to_hex(entry->sha1));
951
952                 /* Check if it is delta, and the base is also an object
953                  * we are going to pack.  If so we will reuse the existing
954                  * delta.
955                  */
956                 if (!no_reuse_delta) {
957                         unsigned char c, *base_name;
958                         unsigned long ofs;
959                         /* there is at least 20 bytes left in the pack */
960                         switch (entry->in_pack_type) {
961                         case OBJ_REF_DELTA:
962                                 base_name = buf + used;
963                                 used += 20;
964                                 break;
965                         case OBJ_OFS_DELTA:
966                                 c = buf[used++];
967                                 ofs = c & 127;
968                                 while (c & 128) {
969                                         ofs += 1;
970                                         if (!ofs || ofs & ~(~0UL >> 7))
971                                                 die("delta base offset overflow in pack for %s",
972                                                     sha1_to_hex(entry->sha1));
973                                         c = buf[used++];
974                                         ofs = (ofs << 7) + (c & 127);
975                                 }
976                                 if (ofs >= entry->in_pack_offset)
977                                         die("delta base offset out of bound for %s",
978                                             sha1_to_hex(entry->sha1));
979                                 ofs = entry->in_pack_offset - ofs;
980                                 base_name = find_packed_object_name(p, ofs);
981                                 break;
982                         default:
983                                 base_name = NULL;
984                         }
985                         if (base_name)
986                                 base_entry = locate_object_entry(base_name);
987                 }
988                 unuse_packed_git(p);
989                 entry->in_pack_header_size = used;
990
991                 if (base_entry) {
992
993                         /* Depth value does not matter - find_deltas()
994                          * will never consider reused delta as the
995                          * base object to deltify other objects
996                          * against, in order to avoid circular deltas.
997                          */
998
999                         /* uncompressed size of the delta data */
1000                         entry->size = size;
1001                         entry->delta = base_entry;
1002                         entry->type = entry->in_pack_type;
1003
1004                         entry->delta_sibling = base_entry->delta_child;
1005                         base_entry->delta_child = entry;
1006
1007                         return;
1008                 }
1009                 /* Otherwise we would do the usual */
1010         }
1011
1012         if (sha1_object_info(entry->sha1, type, &entry->size))
1013                 die("unable to get type of object %s",
1014                     sha1_to_hex(entry->sha1));
1015
1016         if (!strcmp(type, commit_type)) {
1017                 entry->type = OBJ_COMMIT;
1018         } else if (!strcmp(type, tree_type)) {
1019                 entry->type = OBJ_TREE;
1020         } else if (!strcmp(type, blob_type)) {
1021                 entry->type = OBJ_BLOB;
1022         } else if (!strcmp(type, tag_type)) {
1023                 entry->type = OBJ_TAG;
1024         } else
1025                 die("unable to pack object %s of type %s",
1026                     sha1_to_hex(entry->sha1), type);
1027 }
1028
1029 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1030 {
1031         struct object_entry *child = me->delta_child;
1032         unsigned int m = n;
1033         while (child) {
1034                 unsigned int c = check_delta_limit(child, n + 1);
1035                 if (m < c)
1036                         m = c;
1037                 child = child->delta_sibling;
1038         }
1039         return m;
1040 }
1041
1042 static void get_object_details(void)
1043 {
1044         int i;
1045         struct object_entry *entry;
1046
1047         prepare_pack_ix();
1048         for (i = 0, entry = objects; i < nr_objects; i++, entry++)
1049                 check_object(entry);
1050
1051         if (nr_objects == nr_result) {
1052                 /*
1053                  * Depth of objects that depend on the entry -- this
1054                  * is subtracted from depth-max to break too deep
1055                  * delta chain because of delta data reusing.
1056                  * However, we loosen this restriction when we know we
1057                  * are creating a thin pack -- it will have to be
1058                  * expanded on the other end anyway, so do not
1059                  * artificially cut the delta chain and let it go as
1060                  * deep as it wants.
1061                  */
1062                 for (i = 0, entry = objects; i < nr_objects; i++, entry++)
1063                         if (!entry->delta && entry->delta_child)
1064                                 entry->delta_limit =
1065                                         check_delta_limit(entry, 1);
1066         }
1067 }
1068
1069 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
1070
1071 static entry_sort_t current_sort;
1072
1073 static int sort_comparator(const void *_a, const void *_b)
1074 {
1075         struct object_entry *a = *(struct object_entry **)_a;
1076         struct object_entry *b = *(struct object_entry **)_b;
1077         return current_sort(a,b);
1078 }
1079
1080 static struct object_entry **create_sorted_list(entry_sort_t sort)
1081 {
1082         struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
1083         int i;
1084
1085         for (i = 0; i < nr_objects; i++)
1086                 list[i] = objects + i;
1087         current_sort = sort;
1088         qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
1089         return list;
1090 }
1091
1092 static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
1093 {
1094         return hashcmp(a->sha1, b->sha1);
1095 }
1096
1097 static struct object_entry **create_final_object_list(void)
1098 {
1099         struct object_entry **list;
1100         int i, j;
1101
1102         for (i = nr_result = 0; i < nr_objects; i++)
1103                 if (!objects[i].preferred_base)
1104                         nr_result++;
1105         list = xmalloc(nr_result * sizeof(struct object_entry *));
1106         for (i = j = 0; i < nr_objects; i++) {
1107                 if (!objects[i].preferred_base)
1108                         list[j++] = objects + i;
1109         }
1110         current_sort = sha1_sort;
1111         qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
1112         return list;
1113 }
1114
1115 static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
1116 {
1117         if (a->type < b->type)
1118                 return -1;
1119         if (a->type > b->type)
1120                 return 1;
1121         if (a->hash < b->hash)
1122                 return -1;
1123         if (a->hash > b->hash)
1124                 return 1;
1125         if (a->preferred_base < b->preferred_base)
1126                 return -1;
1127         if (a->preferred_base > b->preferred_base)
1128                 return 1;
1129         if (a->size < b->size)
1130                 return -1;
1131         if (a->size > b->size)
1132                 return 1;
1133         return a < b ? -1 : (a > b);
1134 }
1135
1136 struct unpacked {
1137         struct object_entry *entry;
1138         void *data;
1139         struct delta_index *index;
1140 };
1141
1142 /*
1143  * We search for deltas _backwards_ in a list sorted by type and
1144  * by size, so that we see progressively smaller and smaller files.
1145  * That's because we prefer deltas to be from the bigger file
1146  * to the smaller - deletes are potentially cheaper, but perhaps
1147  * more importantly, the bigger file is likely the more recent
1148  * one.
1149  */
1150 static int try_delta(struct unpacked *trg, struct unpacked *src,
1151                      unsigned max_depth)
1152 {
1153         struct object_entry *trg_entry = trg->entry;
1154         struct object_entry *src_entry = src->entry;
1155         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1156         char type[10];
1157         void *delta_buf;
1158
1159         /* Don't bother doing diffs between different types */
1160         if (trg_entry->type != src_entry->type)
1161                 return -1;
1162
1163         /* We do not compute delta to *create* objects we are not
1164          * going to pack.
1165          */
1166         if (trg_entry->preferred_base)
1167                 return -1;
1168
1169         /*
1170          * We do not bother to try a delta that we discarded
1171          * on an earlier try, but only when reusing delta data.
1172          */
1173         if (!no_reuse_delta && trg_entry->in_pack &&
1174             trg_entry->in_pack == src_entry->in_pack)
1175                 return 0;
1176
1177         /*
1178          * If the current object is at pack edge, take the depth the
1179          * objects that depend on the current object into account --
1180          * otherwise they would become too deep.
1181          */
1182         if (trg_entry->delta_child) {
1183                 if (max_depth <= trg_entry->delta_limit)
1184                         return 0;
1185                 max_depth -= trg_entry->delta_limit;
1186         }
1187         if (src_entry->depth >= max_depth)
1188                 return 0;
1189
1190         /* Now some size filtering heuristics. */
1191         trg_size = trg_entry->size;
1192         max_size = trg_size/2 - 20;
1193         max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1194         if (max_size == 0)
1195                 return 0;
1196         if (trg_entry->delta && trg_entry->delta_size <= max_size)
1197                 max_size = trg_entry->delta_size-1;
1198         src_size = src_entry->size;
1199         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1200         if (sizediff >= max_size)
1201                 return 0;
1202
1203         /* Load data if not already done */
1204         if (!trg->data) {
1205                 trg->data = read_sha1_file(trg_entry->sha1, type, &sz);
1206                 if (sz != trg_size)
1207                         die("object %s inconsistent object length (%lu vs %lu)",
1208                             sha1_to_hex(trg_entry->sha1), sz, trg_size);
1209         }
1210         if (!src->data) {
1211                 src->data = read_sha1_file(src_entry->sha1, type, &sz);
1212                 if (sz != src_size)
1213                         die("object %s inconsistent object length (%lu vs %lu)",
1214                             sha1_to_hex(src_entry->sha1), sz, src_size);
1215         }
1216         if (!src->index) {
1217                 src->index = create_delta_index(src->data, src_size);
1218                 if (!src->index)
1219                         die("out of memory");
1220         }
1221
1222         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1223         if (!delta_buf)
1224                 return 0;
1225
1226         trg_entry->delta = src_entry;
1227         trg_entry->delta_size = delta_size;
1228         trg_entry->depth = src_entry->depth + 1;
1229         free(delta_buf);
1230         return 1;
1231 }
1232
1233 static void progress_interval(int signum)
1234 {
1235         progress_update = 1;
1236 }
1237
1238 static void find_deltas(struct object_entry **list, int window, int depth)
1239 {
1240         int i, idx;
1241         unsigned int array_size = window * sizeof(struct unpacked);
1242         struct unpacked *array = xmalloc(array_size);
1243         unsigned processed = 0;
1244         unsigned last_percent = 999;
1245
1246         memset(array, 0, array_size);
1247         i = nr_objects;
1248         idx = 0;
1249         if (progress)
1250                 fprintf(stderr, "Deltifying %d objects.\n", nr_result);
1251
1252         while (--i >= 0) {
1253                 struct object_entry *entry = list[i];
1254                 struct unpacked *n = array + idx;
1255                 int j;
1256
1257                 if (!entry->preferred_base)
1258                         processed++;
1259
1260                 if (progress) {
1261                         unsigned percent = processed * 100 / nr_result;
1262                         if (percent != last_percent || progress_update) {
1263                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
1264                                         percent, processed, nr_result);
1265                                 progress_update = 0;
1266                                 last_percent = percent;
1267                         }
1268                 }
1269
1270                 if (entry->delta)
1271                         /* This happens if we decided to reuse existing
1272                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1273                          */
1274                         continue;
1275
1276                 if (entry->size < 50)
1277                         continue;
1278                 free_delta_index(n->index);
1279                 n->index = NULL;
1280                 free(n->data);
1281                 n->data = NULL;
1282                 n->entry = entry;
1283
1284                 j = window;
1285                 while (--j > 0) {
1286                         unsigned int other_idx = idx + j;
1287                         struct unpacked *m;
1288                         if (other_idx >= window)
1289                                 other_idx -= window;
1290                         m = array + other_idx;
1291                         if (!m->entry)
1292                                 break;
1293                         if (try_delta(n, m, depth) < 0)
1294                                 break;
1295                 }
1296                 /* if we made n a delta, and if n is already at max
1297                  * depth, leaving it in the window is pointless.  we
1298                  * should evict it first.
1299                  */
1300                 if (entry->delta && depth <= entry->depth)
1301                         continue;
1302
1303                 idx++;
1304                 if (idx >= window)
1305                         idx = 0;
1306         }
1307
1308         if (progress)
1309                 fputc('\n', stderr);
1310
1311         for (i = 0; i < window; ++i) {
1312                 free_delta_index(array[i].index);
1313                 free(array[i].data);
1314         }
1315         free(array);
1316 }
1317
1318 static void prepare_pack(int window, int depth)
1319 {
1320         get_object_details();
1321         sorted_by_type = create_sorted_list(type_size_sort);
1322         if (window && depth)
1323                 find_deltas(sorted_by_type, window+1, depth);
1324 }
1325
1326 static int reuse_cached_pack(unsigned char *sha1)
1327 {
1328         static const char cache[] = "pack-cache/pack-%s.%s";
1329         char *cached_pack, *cached_idx;
1330         int ifd, ofd, ifd_ix = -1;
1331
1332         cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
1333         ifd = open(cached_pack, O_RDONLY);
1334         if (ifd < 0)
1335                 return 0;
1336
1337         if (!pack_to_stdout) {
1338                 cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
1339                 ifd_ix = open(cached_idx, O_RDONLY);
1340                 if (ifd_ix < 0) {
1341                         close(ifd);
1342                         return 0;
1343                 }
1344         }
1345
1346         if (progress)
1347                 fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
1348                         sha1_to_hex(sha1));
1349
1350         if (pack_to_stdout) {
1351                 if (copy_fd(ifd, 1))
1352                         exit(1);
1353                 close(ifd);
1354         }
1355         else {
1356                 char name[PATH_MAX];
1357                 snprintf(name, sizeof(name),
1358                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
1359                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1360                 if (ofd < 0)
1361                         die("unable to open %s (%s)", name, strerror(errno));
1362                 if (copy_fd(ifd, ofd))
1363                         exit(1);
1364                 close(ifd);
1365
1366                 snprintf(name, sizeof(name),
1367                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
1368                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1369                 if (ofd < 0)
1370                         die("unable to open %s (%s)", name, strerror(errno));
1371                 if (copy_fd(ifd_ix, ofd))
1372                         exit(1);
1373                 close(ifd_ix);
1374                 puts(sha1_to_hex(sha1));
1375         }
1376
1377         return 1;
1378 }
1379
1380 static void setup_progress_signal(void)
1381 {
1382         struct sigaction sa;
1383         struct itimerval v;
1384
1385         memset(&sa, 0, sizeof(sa));
1386         sa.sa_handler = progress_interval;
1387         sigemptyset(&sa.sa_mask);
1388         sa.sa_flags = SA_RESTART;
1389         sigaction(SIGALRM, &sa, NULL);
1390
1391         v.it_interval.tv_sec = 1;
1392         v.it_interval.tv_usec = 0;
1393         v.it_value = v.it_interval;
1394         setitimer(ITIMER_REAL, &v, NULL);
1395 }
1396
1397 static int git_pack_config(const char *k, const char *v)
1398 {
1399         if(!strcmp(k, "pack.window")) {
1400                 window = git_config_int(k, v);
1401                 return 0;
1402         }
1403         return git_default_config(k, v);
1404 }
1405
1406 static void read_object_list_from_stdin(void)
1407 {
1408         char line[40 + 1 + PATH_MAX + 2];
1409         unsigned char sha1[20];
1410         unsigned hash;
1411
1412         for (;;) {
1413                 if (!fgets(line, sizeof(line), stdin)) {
1414                         if (feof(stdin))
1415                                 break;
1416                         if (!ferror(stdin))
1417                                 die("fgets returned NULL, not EOF, not error!");
1418                         if (errno != EINTR)
1419                                 die("fgets: %s", strerror(errno));
1420                         clearerr(stdin);
1421                         continue;
1422                 }
1423                 if (line[0] == '-') {
1424                         if (get_sha1_hex(line+1, sha1))
1425                                 die("expected edge sha1, got garbage:\n %s",
1426                                     line);
1427                         add_preferred_base(sha1);
1428                         continue;
1429                 }
1430                 if (get_sha1_hex(line, sha1))
1431                         die("expected sha1, got garbage:\n %s", line);
1432
1433                 hash = name_hash(line+41);
1434                 add_preferred_base_object(line+41, hash);
1435                 add_object_entry(sha1, hash, 0);
1436         }
1437 }
1438
1439 static void show_commit(struct commit *commit)
1440 {
1441         unsigned hash = name_hash("");
1442         add_preferred_base_object("", hash);
1443         add_object_entry(commit->object.sha1, hash, 0);
1444 }
1445
1446 static void show_object(struct object_array_entry *p)
1447 {
1448         unsigned hash = name_hash(p->name);
1449         add_preferred_base_object(p->name, hash);
1450         add_object_entry(p->item->sha1, hash, 0);
1451 }
1452
1453 static void show_edge(struct commit *commit)
1454 {
1455         add_preferred_base(commit->object.sha1);
1456 }
1457
1458 static void get_object_list(int ac, const char **av)
1459 {
1460         struct rev_info revs;
1461         char line[1000];
1462         int flags = 0;
1463
1464         init_revisions(&revs, NULL);
1465         save_commit_buffer = 0;
1466         track_object_refs = 0;
1467         setup_revisions(ac, av, &revs, NULL);
1468
1469         while (fgets(line, sizeof(line), stdin) != NULL) {
1470                 int len = strlen(line);
1471                 if (line[len - 1] == '\n')
1472                         line[--len] = 0;
1473                 if (!len)
1474                         break;
1475                 if (*line == '-') {
1476                         if (!strcmp(line, "--not")) {
1477                                 flags ^= UNINTERESTING;
1478                                 continue;
1479                         }
1480                         die("not a rev '%s'", line);
1481                 }
1482                 if (handle_revision_arg(line, &revs, flags, 1))
1483                         die("bad revision '%s'", line);
1484         }
1485
1486         prepare_revision_walk(&revs);
1487         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1488         traverse_commit_list(&revs, show_commit, show_object);
1489 }
1490
1491 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1492 {
1493         SHA_CTX ctx;
1494         int depth = 10;
1495         struct object_entry **list;
1496         int use_internal_rev_list = 0;
1497         int thin = 0;
1498         int i;
1499         const char *rp_av[64];
1500         int rp_ac;
1501
1502         rp_av[0] = "pack-objects";
1503         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1504         rp_ac = 2;
1505
1506         git_config(git_pack_config);
1507
1508         progress = isatty(2);
1509         for (i = 1; i < argc; i++) {
1510                 const char *arg = argv[i];
1511
1512                 if (*arg != '-')
1513                         break;
1514
1515                 if (!strcmp("--non-empty", arg)) {
1516                         non_empty = 1;
1517                         continue;
1518                 }
1519                 if (!strcmp("--local", arg)) {
1520                         local = 1;
1521                         continue;
1522                 }
1523                 if (!strcmp("--progress", arg)) {
1524                         progress = 1;
1525                         continue;
1526                 }
1527                 if (!strcmp("--all-progress", arg)) {
1528                         progress = 2;
1529                         continue;
1530                 }
1531                 if (!strcmp("--incremental", arg)) {
1532                         incremental = 1;
1533                         continue;
1534                 }
1535                 if (!strncmp("--window=", arg, 9)) {
1536                         char *end;
1537                         window = strtoul(arg+9, &end, 0);
1538                         if (!arg[9] || *end)
1539                                 usage(pack_usage);
1540                         continue;
1541                 }
1542                 if (!strncmp("--depth=", arg, 8)) {
1543                         char *end;
1544                         depth = strtoul(arg+8, &end, 0);
1545                         if (!arg[8] || *end)
1546                                 usage(pack_usage);
1547                         continue;
1548                 }
1549                 if (!strcmp("--progress", arg)) {
1550                         progress = 1;
1551                         continue;
1552                 }
1553                 if (!strcmp("-q", arg)) {
1554                         progress = 0;
1555                         continue;
1556                 }
1557                 if (!strcmp("--no-reuse-delta", arg)) {
1558                         no_reuse_delta = 1;
1559                         continue;
1560                 }
1561                 if (!strcmp("--delta-base-offset", arg)) {
1562                         allow_ofs_delta = 1;
1563                         continue;
1564                 }
1565                 if (!strcmp("--stdout", arg)) {
1566                         pack_to_stdout = 1;
1567                         continue;
1568                 }
1569                 if (!strcmp("--revs", arg)) {
1570                         use_internal_rev_list = 1;
1571                         continue;
1572                 }
1573                 if (!strcmp("--unpacked", arg) ||
1574                     !strncmp("--unpacked=", arg, 11) ||
1575                     !strcmp("--all", arg)) {
1576                         use_internal_rev_list = 1;
1577                         if (ARRAY_SIZE(rp_av) - 1 <= rp_ac)
1578                                 die("too many internal rev-list options");
1579                         rp_av[rp_ac++] = arg;
1580                         continue;
1581                 }
1582                 if (!strcmp("--thin", arg)) {
1583                         use_internal_rev_list = 1;
1584                         thin = 1;
1585                         rp_av[1] = "--objects-edge";
1586                         continue;
1587                 }
1588                 usage(pack_usage);
1589         }
1590
1591         /* Traditionally "pack-objects [options] base extra" failed;
1592          * we would however want to take refs parameter that would
1593          * have been given to upstream rev-list ourselves, which means
1594          * we somehow want to say what the base name is.  So the
1595          * syntax would be:
1596          *
1597          * pack-objects [options] base <refs...>
1598          *
1599          * in other words, we would treat the first non-option as the
1600          * base_name and send everything else to the internal revision
1601          * walker.
1602          */
1603
1604         if (!pack_to_stdout)
1605                 base_name = argv[i++];
1606
1607         if (pack_to_stdout != !base_name)
1608                 usage(pack_usage);
1609
1610         if (!pack_to_stdout && thin)
1611                 die("--thin cannot be used to build an indexable pack.");
1612
1613         prepare_packed_git();
1614
1615         if (progress) {
1616                 fprintf(stderr, "Generating pack...\n");
1617                 setup_progress_signal();
1618         }
1619
1620         if (!use_internal_rev_list)
1621                 read_object_list_from_stdin();
1622         else {
1623                 rp_av[rp_ac] = NULL;
1624                 get_object_list(rp_ac, rp_av);
1625         }
1626
1627         if (progress)
1628                 fprintf(stderr, "Done counting %d objects.\n", nr_objects);
1629         sorted_by_sha = create_final_object_list();
1630         if (non_empty && !nr_result)
1631                 return 0;
1632
1633         SHA1_Init(&ctx);
1634         list = sorted_by_sha;
1635         for (i = 0; i < nr_result; i++) {
1636                 struct object_entry *entry = *list++;
1637                 SHA1_Update(&ctx, entry->sha1, 20);
1638         }
1639         SHA1_Final(object_list_sha1, &ctx);
1640         if (progress && (nr_objects != nr_result))
1641                 fprintf(stderr, "Result has %d objects.\n", nr_result);
1642
1643         if (reuse_cached_pack(object_list_sha1))
1644                 ;
1645         else {
1646                 if (nr_result)
1647                         prepare_pack(window, depth);
1648                 if (progress == 1 && pack_to_stdout) {
1649                         /* the other end usually displays progress itself */
1650                         struct itimerval v = {{0,},};
1651                         setitimer(ITIMER_REAL, &v, NULL);
1652                         signal(SIGALRM, SIG_IGN );
1653                         progress_update = 0;
1654                 }
1655                 write_pack_file();
1656                 if (!pack_to_stdout) {
1657                         write_index_file();
1658                         puts(sha1_to_hex(object_list_sha1));
1659                 }
1660         }
1661         if (progress)
1662                 fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
1663                         nr_result, written, written_delta, reused, reused_delta);
1664         return 0;
1665 }