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;
56 static volatile int progress_update
= 0;
59 * The object names in objects array are hashed with this hashtable,
60 * to help looking up the entry by object name. Binary search from
61 * sorted_by_sha is also possible but this was easier to code and faster.
62 * This hashtable is built after all the objects are seen.
64 static int *object_ix
= NULL
;
65 static int object_ix_hashsz
= 0;
68 * Pack index for existing packs give us easy access to the offsets into
69 * corresponding pack file where each object's data starts, but the entries
70 * do not store the size of the compressed representation (uncompressed
71 * size is easily available by examining the pack entry header). We build
72 * a hashtable of existing packs (pack_revindex), and keep reverse index
73 * here -- pack index file is sorted by object name mapping to offset; this
74 * pack_revindex[].revindex array is an ordered list of offsets, so if you
75 * know the offset of an object, next offset is where its packed
76 * representation ends.
78 struct pack_revindex
{
80 unsigned long *revindex
;
81 } *pack_revindex
= NULL
;
82 static int pack_revindex_hashsz
= 0;
87 static int written
= 0;
88 static int written_delta
= 0;
89 static int reused
= 0;
90 static int reused_delta
= 0;
92 static int pack_revindex_ix(struct packed_git
*p
)
94 unsigned int ui
= (unsigned int) p
;
97 ui
= ui
^ (ui
>> 16); /* defeat structure alignment */
98 i
= (int)(ui
% pack_revindex_hashsz
);
99 while (pack_revindex
[i
].p
) {
100 if (pack_revindex
[i
].p
== p
)
102 if (++i
== pack_revindex_hashsz
)
108 static void prepare_pack_ix(void)
111 struct packed_git
*p
;
112 for (num
= 0, p
= packed_git
; p
; p
= p
->next
)
116 pack_revindex_hashsz
= num
* 11;
117 pack_revindex
= xcalloc(sizeof(*pack_revindex
), pack_revindex_hashsz
);
118 for (p
= packed_git
; p
; p
= p
->next
) {
119 num
= pack_revindex_ix(p
);
121 pack_revindex
[num
].p
= p
;
123 /* revindex elements are lazily initialized */
126 static int cmp_offset(const void *a_
, const void *b_
)
128 unsigned long a
= *(unsigned long *) a_
;
129 unsigned long b
= *(unsigned long *) b_
;
139 * Ordered list of offsets of objects in the pack.
141 static void prepare_pack_revindex(struct pack_revindex
*rix
)
143 struct packed_git
*p
= rix
->p
;
144 int num_ent
= num_packed_objects(p
);
146 void *index
= p
->index_base
+ 256;
148 rix
->revindex
= xmalloc(sizeof(unsigned long) * (num_ent
+ 1));
149 for (i
= 0; i
< num_ent
; i
++) {
150 long hl
= *((long *)(index
+ 24 * i
));
151 rix
->revindex
[i
] = ntohl(hl
);
153 /* This knows the pack format -- the 20-byte trailer
154 * follows immediately after the last object data.
156 rix
->revindex
[num_ent
] = p
->pack_size
- 20;
157 qsort(rix
->revindex
, num_ent
, sizeof(unsigned long), cmp_offset
);
160 static unsigned long find_packed_object_size(struct packed_git
*p
,
165 struct pack_revindex
*rix
;
166 unsigned long *revindex
;
167 num
= pack_revindex_ix(p
);
169 die("internal error: pack revindex uninitialized");
170 rix
= &pack_revindex
[num
];
172 prepare_pack_revindex(rix
);
173 revindex
= rix
->revindex
;
175 hi
= num_packed_objects(p
) + 1;
177 int mi
= (lo
+ hi
) / 2;
178 if (revindex
[mi
] == ofs
) {
179 return revindex
[mi
+1] - ofs
;
181 else if (ofs
< revindex
[mi
])
186 die("internal error: pack revindex corrupt");
189 static void *delta_against(void *buf
, unsigned long size
, struct object_entry
*entry
)
191 unsigned long othersize
, delta_size
;
193 void *otherbuf
= read_sha1_file(entry
->delta
->sha1
, type
, &othersize
);
197 die("unable to read %s", sha1_to_hex(entry
->delta
->sha1
));
198 delta_buf
= diff_delta(otherbuf
, othersize
,
199 buf
, size
, &delta_size
, 0);
200 if (!delta_buf
|| delta_size
!= entry
->delta_size
)
201 die("delta size changed");
208 * The per-object header is a pretty dense thing, which is
209 * - first byte: low four bits are "size", then three bits of "type",
210 * and the high bit is "size continues".
211 * - each byte afterwards: low seven bits are size continuation,
212 * with the high bit being "size continues"
214 static int encode_header(enum object_type type
, unsigned long size
, unsigned char *hdr
)
219 if (type
< OBJ_COMMIT
|| type
> OBJ_DELTA
)
220 die("bad type %d", type
);
222 c
= (type
<< 4) | (size
& 15);
234 static unsigned long write_object(struct sha1file
*f
, struct object_entry
*entry
)
239 unsigned char header
[10];
240 unsigned hdrlen
, datalen
;
241 enum object_type obj_type
;
244 obj_type
= entry
->type
;
245 if (! entry
->in_pack
)
246 to_reuse
= 0; /* can't reuse what we don't have */
247 else if (obj_type
== OBJ_DELTA
)
248 to_reuse
= 1; /* check_object() decided it for us */
249 else if (obj_type
!= entry
->in_pack_type
)
250 to_reuse
= 0; /* pack has delta which is unusable */
251 else if (entry
->delta
)
252 to_reuse
= 0; /* we want to pack afresh */
254 to_reuse
= 1; /* we have it in-pack undeltified,
255 * and we do not need to deltify it.
259 buf
= read_sha1_file(entry
->sha1
, type
, &size
);
261 die("unable to read %s", sha1_to_hex(entry
->sha1
));
262 if (size
!= entry
->size
)
263 die("object %s size inconsistency (%lu vs %lu)",
264 sha1_to_hex(entry
->sha1
), size
, entry
->size
);
266 buf
= delta_against(buf
, size
, entry
);
267 size
= entry
->delta_size
;
268 obj_type
= OBJ_DELTA
;
271 * The object header is a byte of 'type' followed by zero or
272 * more bytes of length. For deltas, the 20 bytes of delta
275 hdrlen
= encode_header(obj_type
, size
, header
);
276 sha1write(f
, header
, hdrlen
);
279 sha1write(f
, entry
->delta
, 20);
282 datalen
= sha1write_compressed(f
, buf
, size
);
286 struct packed_git
*p
= entry
->in_pack
;
289 datalen
= find_packed_object_size(p
, entry
->in_pack_offset
);
290 buf
= p
->pack_base
+ entry
->in_pack_offset
;
291 sha1write(f
, buf
, datalen
);
293 hdrlen
= 0; /* not really */
294 if (obj_type
== OBJ_DELTA
)
298 if (obj_type
== OBJ_DELTA
)
301 return hdrlen
+ datalen
;
304 static unsigned long write_one(struct sha1file
*f
,
305 struct object_entry
*e
,
306 unsigned long offset
)
309 /* offset starts from header size and cannot be zero
310 * if it is written already.
314 offset
+= write_object(f
, e
);
315 /* if we are deltified, write out its base object. */
317 offset
= write_one(f
, e
->delta
, offset
);
321 static void write_pack_file(void)
325 unsigned long offset
;
326 struct pack_header hdr
;
329 f
= sha1fd(1, "<stdout>");
331 f
= sha1create("%s-%s.%s", base_name
, sha1_to_hex(object_list_sha1
), "pack");
332 hdr
.hdr_signature
= htonl(PACK_SIGNATURE
);
333 hdr
.hdr_version
= htonl(PACK_VERSION
);
334 hdr
.hdr_entries
= htonl(nr_objects
);
335 sha1write(f
, &hdr
, sizeof(hdr
));
336 offset
= sizeof(hdr
);
337 for (i
= 0; i
< nr_objects
; i
++) {
338 offset
= write_one(f
, objects
+ i
, offset
);
339 if (progress_update
) {
340 fprintf(stderr
, "Writing (%d %d%%)\r",
341 i
+1, (i
+1) * 100/nr_objects
);
346 sha1close(f
, pack_file_sha1
, 1);
349 static void write_index_file(void)
352 struct sha1file
*f
= sha1create("%s-%s.%s", base_name
, sha1_to_hex(object_list_sha1
), "idx");
353 struct object_entry
**list
= sorted_by_sha
;
354 struct object_entry
**last
= list
+ nr_objects
;
355 unsigned int array
[256];
358 * Write the first-level table (the list is sorted,
359 * but we use a 256-entry lookup to be able to avoid
360 * having to do eight extra binary search iterations).
362 for (i
= 0; i
< 256; i
++) {
363 struct object_entry
**next
= list
;
364 while (next
< last
) {
365 struct object_entry
*entry
= *next
;
366 if (entry
->sha1
[0] != i
)
370 array
[i
] = htonl(next
- sorted_by_sha
);
373 sha1write(f
, array
, 256 * sizeof(int));
376 * Write the actual SHA1 entries..
378 list
= sorted_by_sha
;
379 for (i
= 0; i
< nr_objects
; i
++) {
380 struct object_entry
*entry
= *list
++;
381 unsigned int offset
= htonl(entry
->offset
);
382 sha1write(f
, &offset
, 4);
383 sha1write(f
, entry
->sha1
, 20);
385 sha1write(f
, pack_file_sha1
, 20);
386 sha1close(f
, NULL
, 1);
389 static int add_object_entry(unsigned char *sha1
, unsigned int hash
)
391 unsigned int idx
= nr_objects
;
392 struct object_entry
*entry
;
393 struct packed_git
*p
;
394 unsigned int found_offset
= 0;
395 struct packed_git
*found_pack
= NULL
;
397 for (p
= packed_git
; p
; p
= p
->next
) {
399 if (find_pack_entry_one(sha1
, &e
, p
)) {
402 if (local
&& !p
->pack_local
)
405 found_offset
= e
.offset
;
411 if (idx
>= nr_alloc
) {
412 unsigned int needed
= (idx
+ 1024) * 3 / 2;
413 objects
= xrealloc(objects
, needed
* sizeof(*entry
));
416 entry
= objects
+ idx
;
417 memset(entry
, 0, sizeof(*entry
));
418 memcpy(entry
->sha1
, sha1
, 20);
421 entry
->in_pack
= found_pack
;
422 entry
->in_pack_offset
= found_offset
;
428 static int locate_object_entry_hash(unsigned char *sha1
)
432 memcpy(&ui
, sha1
, sizeof(unsigned int));
433 i
= ui
% object_ix_hashsz
;
434 while (0 < object_ix
[i
]) {
435 if (!memcmp(sha1
, objects
[object_ix
[i
]-1].sha1
, 20))
437 if (++i
== object_ix_hashsz
)
443 static struct object_entry
*locate_object_entry(unsigned char *sha1
)
445 int i
= locate_object_entry_hash(sha1
);
447 return &objects
[object_ix
[i
]-1];
451 static void check_object(struct object_entry
*entry
)
455 if (entry
->in_pack
) {
456 unsigned char base
[20];
458 struct object_entry
*base_entry
;
460 /* We want in_pack_type even if we do not reuse delta.
461 * There is no point not reusing non-delta representations.
463 check_reuse_pack_delta(entry
->in_pack
,
464 entry
->in_pack_offset
,
466 &entry
->in_pack_type
);
468 /* Check if it is delta, and the base is also an object
469 * we are going to pack. If so we will reuse the existing
472 if (!no_reuse_delta
&&
473 entry
->in_pack_type
== OBJ_DELTA
&&
474 (base_entry
= locate_object_entry(base
))) {
476 /* Depth value does not matter - find_deltas()
477 * will never consider reused delta as the
478 * base object to deltify other objects
479 * against, in order to avoid circular deltas.
482 /* uncompressed size of the delta data */
483 entry
->size
= entry
->delta_size
= size
;
484 entry
->delta
= base_entry
;
485 entry
->type
= OBJ_DELTA
;
487 entry
->delta_sibling
= base_entry
->delta_child
;
488 base_entry
->delta_child
= entry
;
492 /* Otherwise we would do the usual */
495 if (sha1_object_info(entry
->sha1
, type
, &entry
->size
))
496 die("unable to get type of object %s",
497 sha1_to_hex(entry
->sha1
));
499 if (!strcmp(type
, "commit")) {
500 entry
->type
= OBJ_COMMIT
;
501 } else if (!strcmp(type
, "tree")) {
502 entry
->type
= OBJ_TREE
;
503 } else if (!strcmp(type
, "blob")) {
504 entry
->type
= OBJ_BLOB
;
505 } else if (!strcmp(type
, "tag")) {
506 entry
->type
= OBJ_TAG
;
508 die("unable to pack object %s of type %s",
509 sha1_to_hex(entry
->sha1
), type
);
512 static void hash_objects(void)
515 struct object_entry
*oe
;
517 object_ix_hashsz
= nr_objects
* 2;
518 object_ix
= xcalloc(sizeof(int), object_ix_hashsz
);
519 for (i
= 0, oe
= objects
; i
< nr_objects
; i
++, oe
++) {
520 int ix
= locate_object_entry_hash(oe
->sha1
);
522 error("the same object '%s' added twice",
523 sha1_to_hex(oe
->sha1
));
527 object_ix
[ix
] = i
+ 1;
531 static unsigned int check_delta_limit(struct object_entry
*me
, unsigned int n
)
533 struct object_entry
*child
= me
->delta_child
;
536 unsigned int c
= check_delta_limit(child
, n
+ 1);
539 child
= child
->delta_sibling
;
544 static void get_object_details(void)
547 struct object_entry
*entry
;
551 for (i
= 0, entry
= objects
; i
< nr_objects
; i
++, entry
++)
553 for (i
= 0, entry
= objects
; i
< nr_objects
; i
++, entry
++)
554 if (!entry
->delta
&& entry
->delta_child
)
556 check_delta_limit(entry
, 1);
559 typedef int (*entry_sort_t
)(const struct object_entry
*, const struct object_entry
*);
561 static entry_sort_t current_sort
;
563 static int sort_comparator(const void *_a
, const void *_b
)
565 struct object_entry
*a
= *(struct object_entry
**)_a
;
566 struct object_entry
*b
= *(struct object_entry
**)_b
;
567 return current_sort(a
,b
);
570 static struct object_entry
**create_sorted_list(entry_sort_t sort
)
572 struct object_entry
**list
= xmalloc(nr_objects
* sizeof(struct object_entry
*));
575 for (i
= 0; i
< nr_objects
; i
++)
576 list
[i
] = objects
+ i
;
578 qsort(list
, nr_objects
, sizeof(struct object_entry
*), sort_comparator
);
582 static int sha1_sort(const struct object_entry
*a
, const struct object_entry
*b
)
584 return memcmp(a
->sha1
, b
->sha1
, 20);
587 static int type_size_sort(const struct object_entry
*a
, const struct object_entry
*b
)
589 if (a
->type
< b
->type
)
591 if (a
->type
> b
->type
)
593 if (a
->hash
< b
->hash
)
595 if (a
->hash
> b
->hash
)
597 if (a
->size
< b
->size
)
599 if (a
->size
> b
->size
)
601 return a
< b
? -1 : (a
> b
);
605 struct object_entry
*entry
;
610 * We search for deltas _backwards_ in a list sorted by type and
611 * by size, so that we see progressively smaller and smaller files.
612 * That's because we prefer deltas to be from the bigger file
613 * to the smaller - deletes are potentially cheaper, but perhaps
614 * more importantly, the bigger file is likely the more recent
617 static int try_delta(struct unpacked
*cur
, struct unpacked
*old
, unsigned max_depth
)
619 struct object_entry
*cur_entry
= cur
->entry
;
620 struct object_entry
*old_entry
= old
->entry
;
621 unsigned long size
, oldsize
, delta_size
, sizediff
;
625 /* Don't bother doing diffs between different types */
626 if (cur_entry
->type
!= old_entry
->type
)
629 /* If the current object is at edge, take the depth the objects
630 * that depend on the current object into account -- otherwise
631 * they would become too deep.
633 if (cur_entry
->delta_child
) {
634 if (max_depth
<= cur_entry
->delta_limit
)
636 max_depth
-= cur_entry
->delta_limit
;
639 size
= cur_entry
->size
;
642 oldsize
= old_entry
->size
;
643 sizediff
= oldsize
> size
? oldsize
- size
: size
- oldsize
;
644 if (sizediff
> size
/ 8)
646 if (old_entry
->depth
>= max_depth
)
652 * We always delta from the bigger to the smaller, since that's
653 * more space-efficient (deletes don't have to say _what_ they
656 max_size
= size
/ 2 - 20;
657 if (cur_entry
->delta
)
658 max_size
= cur_entry
->delta_size
-1;
659 if (sizediff
>= max_size
)
661 delta_buf
= diff_delta(old
->data
, oldsize
,
662 cur
->data
, size
, &delta_size
, max_size
);
665 cur_entry
->delta
= old_entry
;
666 cur_entry
->delta_size
= delta_size
;
667 cur_entry
->depth
= old_entry
->depth
+ 1;
672 static void progress_interval(int signum
)
674 signal(SIGALRM
, progress_interval
);
678 static void find_deltas(struct object_entry
**list
, int window
, int depth
)
681 unsigned int array_size
= window
* sizeof(struct unpacked
);
682 struct unpacked
*array
= xmalloc(array_size
);
684 memset(array
, 0, array_size
);
689 struct object_entry
*entry
= list
[i
];
690 struct unpacked
*n
= array
+ idx
;
695 if (progress_update
|| i
== 0) {
696 fprintf(stderr
, "Deltifying (%d %d%%)\r",
697 nr_objects
-i
, (nr_objects
-i
) * 100/nr_objects
);
702 /* This happens if we decided to reuse existing
703 * delta from a pack. "!no_reuse_delta &&" is implied.
709 n
->data
= read_sha1_file(entry
->sha1
, type
, &size
);
710 if (size
!= entry
->size
)
711 die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry
->sha1
), size
, entry
->size
);
715 unsigned int other_idx
= idx
+ j
;
717 if (other_idx
>= window
)
719 m
= array
+ other_idx
;
722 if (try_delta(n
, m
, depth
) < 0)
733 for (i
= 0; i
< window
; ++i
)
738 static void prepare_pack(int window
, int depth
)
740 get_object_details();
741 sorted_by_type
= create_sorted_list(type_size_sort
);
743 find_deltas(sorted_by_type
, window
+1, depth
);
746 static int reuse_cached_pack(unsigned char *sha1
, int pack_to_stdout
)
748 static const char cache
[] = "pack-cache/pack-%s.%s";
749 char *cached_pack
, *cached_idx
;
750 int ifd
, ofd
, ifd_ix
= -1;
752 cached_pack
= git_path(cache
, sha1_to_hex(sha1
), "pack");
753 ifd
= open(cached_pack
, O_RDONLY
);
757 if (!pack_to_stdout
) {
758 cached_idx
= git_path(cache
, sha1_to_hex(sha1
), "idx");
759 ifd_ix
= open(cached_idx
, O_RDONLY
);
767 fprintf(stderr
, "Reusing %d objects pack %s\n", nr_objects
,
770 if (pack_to_stdout
) {
777 snprintf(name
, sizeof(name
),
778 "%s-%s.%s", base_name
, sha1_to_hex(sha1
), "pack");
779 ofd
= open(name
, O_CREAT
| O_EXCL
| O_WRONLY
, 0666);
781 die("unable to open %s (%s)", name
, strerror(errno
));
782 if (copy_fd(ifd
, ofd
))
786 snprintf(name
, sizeof(name
),
787 "%s-%s.%s", base_name
, sha1_to_hex(sha1
), "idx");
788 ofd
= open(name
, O_CREAT
| O_EXCL
| O_WRONLY
, 0666);
790 die("unable to open %s (%s)", name
, strerror(errno
));
791 if (copy_fd(ifd_ix
, ofd
))
794 puts(sha1_to_hex(sha1
));
800 int main(int argc
, char **argv
)
803 char line
[PATH_MAX
+ 20];
804 int window
= 10, depth
= 10, pack_to_stdout
= 0;
805 struct object_entry
**list
;
808 setup_git_directory();
810 for (i
= 1; i
< argc
; i
++) {
811 const char *arg
= argv
[i
];
814 if (!strcmp("--non-empty", arg
)) {
818 if (!strcmp("--local", arg
)) {
822 if (!strcmp("--incremental", arg
)) {
826 if (!strncmp("--window=", arg
, 9)) {
828 window
= strtoul(arg
+9, &end
, 0);
833 if (!strncmp("--depth=", arg
, 8)) {
835 depth
= strtoul(arg
+8, &end
, 0);
840 if (!strcmp("-q", arg
)) {
844 if (!strcmp("--no-reuse-delta", arg
)) {
848 if (!strcmp("--stdout", arg
)) {
859 if (pack_to_stdout
!= !base_name
)
862 prepare_packed_git();
866 v
.it_interval
.tv_sec
= 1;
867 v
.it_interval
.tv_usec
= 0;
868 v
.it_value
= v
.it_interval
;
869 signal(SIGALRM
, progress_interval
);
870 setitimer(ITIMER_REAL
, &v
, NULL
);
871 fprintf(stderr
, "Generating pack...\n");
874 while (fgets(line
, sizeof(line
), stdin
) != NULL
) {
877 unsigned char sha1
[20];
879 if (progress_update
) {
880 fprintf(stderr
, "Counting objects...%d\r", nr_objects
);
883 if (get_sha1_hex(line
, sha1
))
884 die("expected sha1, got garbage:\n %s", line
);
888 unsigned char c
= *p
++;
891 hash
= hash
* 11 + c
;
893 add_object_entry(sha1
, hash
);
896 fprintf(stderr
, "Done counting %d objects.\n", nr_objects
);
897 if (non_empty
&& !nr_objects
)
900 sorted_by_sha
= create_sorted_list(sha1_sort
);
902 list
= sorted_by_sha
;
903 for (i
= 0; i
< nr_objects
; i
++) {
904 struct object_entry
*entry
= *list
++;
905 SHA1_Update(&ctx
, entry
->sha1
, 20);
907 SHA1_Final(object_list_sha1
, &ctx
);
909 if (reuse_cached_pack(object_list_sha1
, pack_to_stdout
))
912 prepare_pack(window
, depth
);
913 if (progress
&& pack_to_stdout
) {
914 /* the other end usually displays progress itself */
915 struct itimerval v
= {{0,},};
916 setitimer(ITIMER_REAL
, &v
, NULL
);
917 signal(SIGALRM
, SIG_IGN
);
921 if (!pack_to_stdout
) {
923 puts(sha1_to_hex(object_list_sha1
));
927 fprintf(stderr
, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
928 nr_objects
, written
, written_delta
, reused
, reused_delta
);