9 static const char pack_usage
[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
12 unsigned char sha1
[20];
13 unsigned long size
; /* uncompressed size */
14 unsigned long offset
; /* offset into the final pack file;
15 * nonzero if already written.
17 unsigned int depth
; /* delta depth */
18 unsigned int delta_limit
; /* base adjustment for in-pack delta */
19 unsigned int hash
; /* name hint hash */
20 enum object_type type
;
21 enum object_type in_pack_type
; /* could be delta */
22 unsigned long delta_size
; /* delta data size (uncompressed) */
23 struct object_entry
*delta
; /* delta base object */
24 struct packed_git
*in_pack
; /* already in pack */
25 unsigned int in_pack_offset
;
26 struct object_entry
*delta_child
; /* delitified objects who bases me */
27 struct object_entry
*delta_sibling
; /* other deltified objects who
28 * uses the same base as me
33 * Objects we are going to pack are colected in objects array (dynamically
34 * expanded). nr_objects & nr_alloc controls this array. They are stored
35 * in the order we see -- typically rev-list --objects order that gives us
36 * nice "minimum seek" order.
38 * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
39 * elements in the objects array. The former is used to build the pack
40 * index (lists object names in the ascending order to help offset lookup),
41 * and the latter is used to group similar things together by try_delta()
45 static unsigned char object_list_sha1
[20];
46 static int non_empty
= 0;
47 static int no_reuse_delta
= 0;
49 static int incremental
= 0;
50 static struct object_entry
**sorted_by_sha
, **sorted_by_type
;
51 static struct object_entry
*objects
= NULL
;
52 static int nr_objects
= 0, nr_alloc
= 0;
53 static const char *base_name
;
54 static unsigned char pack_file_sha1
[20];
55 static int progress
= 1;
58 * The object names in objects array are hashed with this hashtable,
59 * to help looking up the entry by object name. Binary search from
60 * sorted_by_sha is also possible but this was easier to code and faster.
61 * This hashtable is built after all the objects are seen.
63 static int *object_ix
= NULL
;
64 static int object_ix_hashsz
= 0;
67 * Pack index for existing packs give us easy access to the offsets into
68 * corresponding pack file where each object's data starts, but the entries
69 * do not store the size of the compressed representation (uncompressed
70 * size is easily available by examining the pack entry header). We build
71 * a hashtable of existing packs (pack_revindex), and keep reverse index
72 * here -- pack index file is sorted by object name mapping to offset; this
73 * pack_revindex[].revindex array is an ordered list of offsets, so if you
74 * know the offset of an object, next offset is where its packed
75 * representation ends.
77 struct pack_revindex
{
79 unsigned long *revindex
;
80 } *pack_revindex
= NULL
;
81 static int pack_revindex_hashsz
= 0;
86 static int written
= 0;
87 static int written_delta
= 0;
88 static int reused
= 0;
89 static int reused_delta
= 0;
91 static int pack_revindex_ix(struct packed_git
*p
)
93 unsigned int ui
= (unsigned int) p
;
96 ui
= ui
^ (ui
>> 16); /* defeat structure alignment */
97 i
= (int)(ui
% pack_revindex_hashsz
);
98 while (pack_revindex
[i
].p
) {
99 if (pack_revindex
[i
].p
== p
)
101 if (++i
== pack_revindex_hashsz
)
107 static void prepare_pack_ix(void)
110 struct packed_git
*p
;
111 for (num
= 0, p
= packed_git
; p
; p
= p
->next
)
115 pack_revindex_hashsz
= num
* 11;
116 pack_revindex
= xcalloc(sizeof(*pack_revindex
), pack_revindex_hashsz
);
117 for (p
= packed_git
; p
; p
= p
->next
) {
118 num
= pack_revindex_ix(p
);
120 pack_revindex
[num
].p
= p
;
122 /* revindex elements are lazily initialized */
125 static int cmp_offset(const void *a_
, const void *b_
)
127 unsigned long a
= *(unsigned long *) a_
;
128 unsigned long b
= *(unsigned long *) b_
;
138 * Ordered list of offsets of objects in the pack.
140 static void prepare_pack_revindex(struct pack_revindex
*rix
)
142 struct packed_git
*p
= rix
->p
;
143 int num_ent
= num_packed_objects(p
);
145 void *index
= p
->index_base
+ 256;
147 rix
->revindex
= xmalloc(sizeof(unsigned long) * (num_ent
+ 1));
148 for (i
= 0; i
< num_ent
; i
++) {
149 long hl
= *((long *)(index
+ 24 * i
));
150 rix
->revindex
[i
] = ntohl(hl
);
152 /* This knows the pack format -- the 20-byte trailer
153 * follows immediately after the last object data.
155 rix
->revindex
[num_ent
] = p
->pack_size
- 20;
156 qsort(rix
->revindex
, num_ent
, sizeof(unsigned long), cmp_offset
);
159 static unsigned long find_packed_object_size(struct packed_git
*p
,
164 struct pack_revindex
*rix
;
165 unsigned long *revindex
;
166 num
= pack_revindex_ix(p
);
168 die("internal error: pack revindex uninitialized");
169 rix
= &pack_revindex
[num
];
171 prepare_pack_revindex(rix
);
172 revindex
= rix
->revindex
;
174 hi
= num_packed_objects(p
) + 1;
176 int mi
= (lo
+ hi
) / 2;
177 if (revindex
[mi
] == ofs
) {
178 return revindex
[mi
+1] - ofs
;
180 else if (ofs
< revindex
[mi
])
185 die("internal error: pack revindex corrupt");
188 static void *delta_against(void *buf
, unsigned long size
, struct object_entry
*entry
)
190 unsigned long othersize
, delta_size
;
192 void *otherbuf
= read_sha1_file(entry
->delta
->sha1
, type
, &othersize
);
196 die("unable to read %s", sha1_to_hex(entry
->delta
->sha1
));
197 delta_buf
= diff_delta(otherbuf
, othersize
,
198 buf
, size
, &delta_size
, 0);
199 if (!delta_buf
|| delta_size
!= entry
->delta_size
)
200 die("delta size changed");
207 * The per-object header is a pretty dense thing, which is
208 * - first byte: low four bits are "size", then three bits of "type",
209 * and the high bit is "size continues".
210 * - each byte afterwards: low seven bits are size continuation,
211 * with the high bit being "size continues"
213 static int encode_header(enum object_type type
, unsigned long size
, unsigned char *hdr
)
218 if (type
< OBJ_COMMIT
|| type
> OBJ_DELTA
)
219 die("bad type %d", type
);
221 c
= (type
<< 4) | (size
& 15);
233 static unsigned long write_object(struct sha1file
*f
, struct object_entry
*entry
)
238 unsigned char header
[10];
239 unsigned hdrlen
, datalen
;
240 enum object_type obj_type
;
243 obj_type
= entry
->type
;
244 if (! entry
->in_pack
)
245 to_reuse
= 0; /* can't reuse what we don't have */
246 else if (obj_type
== OBJ_DELTA
)
247 to_reuse
= 1; /* check_object() decided it for us */
248 else if (obj_type
!= entry
->in_pack_type
)
249 to_reuse
= 0; /* pack has delta which is unusable */
250 else if (entry
->delta
)
251 to_reuse
= 0; /* we want to pack afresh */
253 to_reuse
= 1; /* we have it in-pack undeltified,
254 * and we do not need to deltify it.
258 buf
= read_sha1_file(entry
->sha1
, type
, &size
);
260 die("unable to read %s", sha1_to_hex(entry
->sha1
));
261 if (size
!= entry
->size
)
262 die("object %s size inconsistency (%lu vs %lu)",
263 sha1_to_hex(entry
->sha1
), size
, entry
->size
);
265 buf
= delta_against(buf
, size
, entry
);
266 size
= entry
->delta_size
;
267 obj_type
= OBJ_DELTA
;
270 * The object header is a byte of 'type' followed by zero or
271 * more bytes of length. For deltas, the 20 bytes of delta
274 hdrlen
= encode_header(obj_type
, size
, header
);
275 sha1write(f
, header
, hdrlen
);
278 sha1write(f
, entry
->delta
, 20);
281 datalen
= sha1write_compressed(f
, buf
, size
);
285 struct packed_git
*p
= entry
->in_pack
;
288 datalen
= find_packed_object_size(p
, entry
->in_pack_offset
);
289 buf
= p
->pack_base
+ entry
->in_pack_offset
;
290 sha1write(f
, buf
, datalen
);
292 hdrlen
= 0; /* not really */
293 if (obj_type
== OBJ_DELTA
)
297 if (obj_type
== OBJ_DELTA
)
300 return hdrlen
+ datalen
;
303 static unsigned long write_one(struct sha1file
*f
,
304 struct object_entry
*e
,
305 unsigned long offset
)
308 /* offset starts from header size and cannot be zero
309 * if it is written already.
313 offset
+= write_object(f
, e
);
314 /* if we are deltified, write out its base object. */
316 offset
= write_one(f
, e
->delta
, offset
);
320 static void write_pack_file(void)
324 unsigned long offset
;
325 struct pack_header hdr
;
328 f
= sha1fd(1, "<stdout>");
330 f
= sha1create("%s-%s.%s", base_name
, sha1_to_hex(object_list_sha1
), "pack");
331 hdr
.hdr_signature
= htonl(PACK_SIGNATURE
);
332 hdr
.hdr_version
= htonl(PACK_VERSION
);
333 hdr
.hdr_entries
= htonl(nr_objects
);
334 sha1write(f
, &hdr
, sizeof(hdr
));
335 offset
= sizeof(hdr
);
336 for (i
= 0; i
< nr_objects
; i
++)
337 offset
= write_one(f
, objects
+ i
, offset
);
339 sha1close(f
, pack_file_sha1
, 1);
342 static void write_index_file(void)
345 struct sha1file
*f
= sha1create("%s-%s.%s", base_name
, sha1_to_hex(object_list_sha1
), "idx");
346 struct object_entry
**list
= sorted_by_sha
;
347 struct object_entry
**last
= list
+ nr_objects
;
348 unsigned int array
[256];
351 * Write the first-level table (the list is sorted,
352 * but we use a 256-entry lookup to be able to avoid
353 * having to do eight extra binary search iterations).
355 for (i
= 0; i
< 256; i
++) {
356 struct object_entry
**next
= list
;
357 while (next
< last
) {
358 struct object_entry
*entry
= *next
;
359 if (entry
->sha1
[0] != i
)
363 array
[i
] = htonl(next
- sorted_by_sha
);
366 sha1write(f
, array
, 256 * sizeof(int));
369 * Write the actual SHA1 entries..
371 list
= sorted_by_sha
;
372 for (i
= 0; i
< nr_objects
; i
++) {
373 struct object_entry
*entry
= *list
++;
374 unsigned int offset
= htonl(entry
->offset
);
375 sha1write(f
, &offset
, 4);
376 sha1write(f
, entry
->sha1
, 20);
378 sha1write(f
, pack_file_sha1
, 20);
379 sha1close(f
, NULL
, 1);
382 static int add_object_entry(unsigned char *sha1
, unsigned int hash
)
384 unsigned int idx
= nr_objects
;
385 struct object_entry
*entry
;
386 struct packed_git
*p
;
387 unsigned int found_offset
= 0;
388 struct packed_git
*found_pack
= NULL
;
390 for (p
= packed_git
; p
; p
= p
->next
) {
392 if (find_pack_entry_one(sha1
, &e
, p
)) {
395 if (local
&& !p
->pack_local
)
398 found_offset
= e
.offset
;
404 if (idx
>= nr_alloc
) {
405 unsigned int needed
= (idx
+ 1024) * 3 / 2;
406 objects
= xrealloc(objects
, needed
* sizeof(*entry
));
409 entry
= objects
+ idx
;
410 memset(entry
, 0, sizeof(*entry
));
411 memcpy(entry
->sha1
, sha1
, 20);
414 entry
->in_pack
= found_pack
;
415 entry
->in_pack_offset
= found_offset
;
421 static int locate_object_entry_hash(unsigned char *sha1
)
425 memcpy(&ui
, sha1
, sizeof(unsigned int));
426 i
= ui
% object_ix_hashsz
;
427 while (0 < object_ix
[i
]) {
428 if (!memcmp(sha1
, objects
[object_ix
[i
]-1].sha1
, 20))
430 if (++i
== object_ix_hashsz
)
436 static struct object_entry
*locate_object_entry(unsigned char *sha1
)
438 int i
= locate_object_entry_hash(sha1
);
440 return &objects
[object_ix
[i
]-1];
444 static void check_object(struct object_entry
*entry
)
448 if (entry
->in_pack
) {
449 unsigned char base
[20];
451 struct object_entry
*base_entry
;
453 /* We want in_pack_type even if we do not reuse delta.
454 * There is no point not reusing non-delta representations.
456 check_reuse_pack_delta(entry
->in_pack
,
457 entry
->in_pack_offset
,
459 &entry
->in_pack_type
);
461 /* Check if it is delta, and the base is also an object
462 * we are going to pack. If so we will reuse the existing
465 if (!no_reuse_delta
&&
466 entry
->in_pack_type
== OBJ_DELTA
&&
467 (base_entry
= locate_object_entry(base
))) {
469 /* Depth value does not matter - find_deltas()
470 * will never consider reused delta as the
471 * base object to deltify other objects
472 * against, in order to avoid circular deltas.
475 /* uncompressed size of the delta data */
476 entry
->size
= entry
->delta_size
= size
;
477 entry
->delta
= base_entry
;
478 entry
->type
= OBJ_DELTA
;
480 entry
->delta_sibling
= base_entry
->delta_child
;
481 base_entry
->delta_child
= entry
;
485 /* Otherwise we would do the usual */
488 if (sha1_object_info(entry
->sha1
, type
, &entry
->size
))
489 die("unable to get type of object %s",
490 sha1_to_hex(entry
->sha1
));
492 if (!strcmp(type
, "commit")) {
493 entry
->type
= OBJ_COMMIT
;
494 } else if (!strcmp(type
, "tree")) {
495 entry
->type
= OBJ_TREE
;
496 } else if (!strcmp(type
, "blob")) {
497 entry
->type
= OBJ_BLOB
;
498 } else if (!strcmp(type
, "tag")) {
499 entry
->type
= OBJ_TAG
;
501 die("unable to pack object %s of type %s",
502 sha1_to_hex(entry
->sha1
), type
);
505 static void hash_objects(void)
508 struct object_entry
*oe
;
510 object_ix_hashsz
= nr_objects
* 2;
511 object_ix
= xcalloc(sizeof(int), object_ix_hashsz
);
512 for (i
= 0, oe
= objects
; i
< nr_objects
; i
++, oe
++) {
513 int ix
= locate_object_entry_hash(oe
->sha1
);
515 error("the same object '%s' added twice",
516 sha1_to_hex(oe
->sha1
));
520 object_ix
[ix
] = i
+ 1;
524 static unsigned int check_delta_limit(struct object_entry
*me
, unsigned int n
)
526 struct object_entry
*child
= me
->delta_child
;
529 unsigned int c
= check_delta_limit(child
, n
+ 1);
532 child
= child
->delta_sibling
;
537 static void get_object_details(void)
540 struct object_entry
*entry
;
544 for (i
= 0, entry
= objects
; i
< nr_objects
; i
++, entry
++)
546 for (i
= 0, entry
= objects
; i
< nr_objects
; i
++, entry
++)
547 if (!entry
->delta
&& entry
->delta_child
)
549 check_delta_limit(entry
, 1);
552 typedef int (*entry_sort_t
)(const struct object_entry
*, const struct object_entry
*);
554 static entry_sort_t current_sort
;
556 static int sort_comparator(const void *_a
, const void *_b
)
558 struct object_entry
*a
= *(struct object_entry
**)_a
;
559 struct object_entry
*b
= *(struct object_entry
**)_b
;
560 return current_sort(a
,b
);
563 static struct object_entry
**create_sorted_list(entry_sort_t sort
)
565 struct object_entry
**list
= xmalloc(nr_objects
* sizeof(struct object_entry
*));
568 for (i
= 0; i
< nr_objects
; i
++)
569 list
[i
] = objects
+ i
;
571 qsort(list
, nr_objects
, sizeof(struct object_entry
*), sort_comparator
);
575 static int sha1_sort(const struct object_entry
*a
, const struct object_entry
*b
)
577 return memcmp(a
->sha1
, b
->sha1
, 20);
580 static int type_size_sort(const struct object_entry
*a
, const struct object_entry
*b
)
582 if (a
->type
< b
->type
)
584 if (a
->type
> b
->type
)
586 if (a
->hash
< b
->hash
)
588 if (a
->hash
> b
->hash
)
590 if (a
->size
< b
->size
)
592 if (a
->size
> b
->size
)
594 return a
< b
? -1 : (a
> b
);
598 struct object_entry
*entry
;
603 * We search for deltas _backwards_ in a list sorted by type and
604 * by size, so that we see progressively smaller and smaller files.
605 * That's because we prefer deltas to be from the bigger file
606 * to the smaller - deletes are potentially cheaper, but perhaps
607 * more importantly, the bigger file is likely the more recent
610 static int try_delta(struct unpacked
*cur
, struct unpacked
*old
, unsigned max_depth
)
612 struct object_entry
*cur_entry
= cur
->entry
;
613 struct object_entry
*old_entry
= old
->entry
;
614 unsigned long size
, oldsize
, delta_size
, sizediff
;
618 /* Don't bother doing diffs between different types */
619 if (cur_entry
->type
!= old_entry
->type
)
622 /* If the current object is at edge, take the depth the objects
623 * that depend on the current object into account -- otherwise
624 * they would become too deep.
626 if (cur_entry
->delta_child
) {
627 if (max_depth
<= cur_entry
->delta_limit
)
629 max_depth
-= cur_entry
->delta_limit
;
632 size
= cur_entry
->size
;
635 oldsize
= old_entry
->size
;
636 sizediff
= oldsize
> size
? oldsize
- size
: size
- oldsize
;
637 if (sizediff
> size
/ 8)
639 if (old_entry
->depth
>= max_depth
)
645 * We always delta from the bigger to the smaller, since that's
646 * more space-efficient (deletes don't have to say _what_ they
649 max_size
= size
/ 2 - 20;
650 if (cur_entry
->delta
)
651 max_size
= cur_entry
->delta_size
-1;
652 if (sizediff
>= max_size
)
654 delta_buf
= diff_delta(old
->data
, oldsize
,
655 cur
->data
, size
, &delta_size
, max_size
);
658 cur_entry
->delta
= old_entry
;
659 cur_entry
->delta_size
= delta_size
;
660 cur_entry
->depth
= old_entry
->depth
+ 1;
665 static volatile int progress_update
= 0;
666 static void progress_interval(int signum
)
668 signal(SIGALRM
, progress_interval
);
672 static void find_deltas(struct object_entry
**list
, int window
, int depth
)
675 unsigned int array_size
= window
* sizeof(struct unpacked
);
676 struct unpacked
*array
= xmalloc(array_size
);
678 memset(array
, 0, array_size
);
683 struct object_entry
*entry
= list
[i
];
684 struct unpacked
*n
= array
+ idx
;
689 if (progress_update
|| i
== 0) {
690 fprintf(stderr
, "Deltifying (%d %d%%)\r",
691 nr_objects
-i
, (nr_objects
-i
) * 100/nr_objects
);
696 /* This happens if we decided to reuse existing
697 * delta from a pack. "!no_reuse_delta &&" is implied.
703 n
->data
= read_sha1_file(entry
->sha1
, type
, &size
);
704 if (size
!= entry
->size
)
705 die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry
->sha1
), size
, entry
->size
);
709 unsigned int other_idx
= idx
+ j
;
711 if (other_idx
>= window
)
713 m
= array
+ other_idx
;
716 if (try_delta(n
, m
, depth
) < 0)
727 for (i
= 0; i
< window
; ++i
)
732 static void prepare_pack(int window
, int depth
)
734 get_object_details();
735 sorted_by_type
= create_sorted_list(type_size_sort
);
737 find_deltas(sorted_by_type
, window
+1, depth
);
741 static int reuse_cached_pack(unsigned char *sha1
, int pack_to_stdout
)
743 static const char cache
[] = "pack-cache/pack-%s.%s";
744 char *cached_pack
, *cached_idx
;
745 int ifd
, ofd
, ifd_ix
= -1;
747 cached_pack
= git_path(cache
, sha1_to_hex(sha1
), "pack");
748 ifd
= open(cached_pack
, O_RDONLY
);
752 if (!pack_to_stdout
) {
753 cached_idx
= git_path(cache
, sha1_to_hex(sha1
), "idx");
754 ifd_ix
= open(cached_idx
, O_RDONLY
);
762 fprintf(stderr
, "Reusing %d objects pack %s\n", nr_objects
,
765 if (pack_to_stdout
) {
772 snprintf(name
, sizeof(name
),
773 "%s-%s.%s", base_name
, sha1_to_hex(sha1
), "pack");
774 ofd
= open(name
, O_CREAT
| O_EXCL
| O_WRONLY
, 0666);
776 die("unable to open %s (%s)", name
, strerror(errno
));
777 if (copy_fd(ifd
, ofd
))
781 snprintf(name
, sizeof(name
),
782 "%s-%s.%s", base_name
, sha1_to_hex(sha1
), "idx");
783 ofd
= open(name
, O_CREAT
| O_EXCL
| O_WRONLY
, 0666);
785 die("unable to open %s (%s)", name
, strerror(errno
));
786 if (copy_fd(ifd_ix
, ofd
))
789 puts(sha1_to_hex(sha1
));
795 int main(int argc
, char **argv
)
798 char line
[PATH_MAX
+ 20];
799 int window
= 10, depth
= 10, pack_to_stdout
= 0;
800 struct object_entry
**list
;
803 setup_git_directory();
805 for (i
= 1; i
< argc
; i
++) {
806 const char *arg
= argv
[i
];
809 if (!strcmp("--non-empty", arg
)) {
813 if (!strcmp("--local", arg
)) {
817 if (!strcmp("--incremental", arg
)) {
821 if (!strncmp("--window=", arg
, 9)) {
823 window
= strtoul(arg
+9, &end
, 0);
828 if (!strncmp("--depth=", arg
, 8)) {
830 depth
= strtoul(arg
+8, &end
, 0);
835 if (!strcmp("-q", arg
)) {
839 if (!strcmp("--no-reuse-delta", arg
)) {
843 if (!strcmp("--stdout", arg
)) {
854 if (pack_to_stdout
!= !base_name
)
857 prepare_packed_git();
861 v
.it_interval
.tv_sec
= 1;
862 v
.it_interval
.tv_usec
= 0;
863 v
.it_value
= v
.it_interval
;
864 signal(SIGALRM
, progress_interval
);
865 setitimer(ITIMER_REAL
, &v
, NULL
);
866 fprintf(stderr
, "Generating pack...\n");
869 while (fgets(line
, sizeof(line
), stdin
) != NULL
) {
872 unsigned char sha1
[20];
874 if (progress_update
) {
875 fprintf(stderr
, "Counting objects...%d\r", nr_objects
);
878 if (get_sha1_hex(line
, sha1
))
879 die("expected sha1, got garbage:\n %s", line
);
883 unsigned char c
= *p
++;
886 hash
= hash
* 11 + c
;
888 add_object_entry(sha1
, hash
);
891 fprintf(stderr
, "Done counting %d objects.\n", nr_objects
);
892 if (non_empty
&& !nr_objects
)
895 sorted_by_sha
= create_sorted_list(sha1_sort
);
897 list
= sorted_by_sha
;
898 for (i
= 0; i
< nr_objects
; i
++) {
899 struct object_entry
*entry
= *list
++;
900 SHA1_Update(&ctx
, entry
->sha1
, 20);
902 SHA1_Final(object_list_sha1
, &ctx
);
904 if (reuse_cached_pack(object_list_sha1
, pack_to_stdout
))
907 prepare_pack(window
, depth
);
908 if (!pack_to_stdout
) {
910 puts(sha1_to_hex(object_list_sha1
));
914 fprintf(stderr
, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
915 nr_objects
, written
, written_delta
, reused
, reused_delta
);