8 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";
11 unsigned char sha1
[20];
12 unsigned long size
; /* uncompressed size */
13 unsigned long offset
; /* offset into the final pack file (nonzero if already written) */
14 unsigned int depth
; /* delta depth */
15 unsigned int hash
; /* name hint hash */
16 enum object_type type
;
17 unsigned char edge
; /* reused delta chain points at this entry. */
18 enum object_type in_pack_type
; /* could be delta */
19 unsigned long delta_size
; /* delta data size (uncompressed) */
20 struct object_entry
*delta
; /* delta base object */
21 struct packed_git
*in_pack
; /* already in pack */
22 unsigned int in_pack_offset
;
26 * Objects we are going to pack are colected in objects array (dynamically
27 * expanded). nr_objects & nr_alloc controls this array. They are stored
28 * in the order we see -- typically rev-list --objects order that gives us
29 * nice "minimum seek" order.
31 * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
32 * elements in the objects array. The former is used to build the pack
33 * index (lists object names in the ascending order to help offset lookup),
34 * and the latter is used to group similar things together by try_delta()
38 static unsigned char object_list_sha1
[20];
39 static int non_empty
= 0;
40 static int no_reuse_delta
= 0;
42 static int incremental
= 0;
43 static struct object_entry
**sorted_by_sha
, **sorted_by_type
;
44 static struct object_entry
*objects
= NULL
;
45 static int nr_objects
= 0, nr_alloc
= 0;
46 static const char *base_name
;
47 static unsigned char pack_file_sha1
[20];
48 static int progress
= 1;
51 * The object names in objects array are hashed with this hashtable,
52 * to help looking up the entry by object name. Binary search from
53 * sorted_by_sha is also possible but this was easier to code and faster.
54 * This hashtable is built after all the objects are seen.
56 static int *object_ix
= NULL
;
57 static int object_ix_hashsz
= 0;
60 * Pack index for existing packs give us easy access to the offsets into
61 * corresponding pack file where each object's data starts, but the entries
62 * do not store the size of the compressed representation (uncompressed
63 * size is easily available by examining the pack entry header). We build
64 * a hashtable of existing packs (pack_revindex), and keep reverse index
65 * here -- pack index file is sorted by object name mapping to offset; this
66 * pack_revindex[].revindex array is an ordered list of offsets, so if you
67 * know the offset of an object, next offset is where its packed
68 * representation ends.
70 struct pack_revindex
{
72 unsigned long *revindex
;
73 } *pack_revindex
= NULL
;
74 static int pack_revindex_hashsz
= 0;
79 static int written
= 0;
80 static int written_delta
= 0;
81 static int reused
= 0;
82 static int reused_delta
= 0;
84 static int pack_revindex_ix(struct packed_git
*p
)
86 unsigned int ui
= (unsigned int) p
;
89 ui
= ui
^ (ui
>> 16); /* defeat structure alignment */
90 i
= (int)(ui
% pack_revindex_hashsz
);
91 while (pack_revindex
[i
].p
) {
92 if (pack_revindex
[i
].p
== p
)
94 if (++i
== pack_revindex_hashsz
)
100 static void prepare_pack_ix(void)
103 struct packed_git
*p
;
104 for (num
= 0, p
= packed_git
; p
; p
= p
->next
)
108 pack_revindex_hashsz
= num
* 11;
109 pack_revindex
= xcalloc(sizeof(*pack_revindex
), pack_revindex_hashsz
);
110 for (p
= packed_git
; p
; p
= p
->next
) {
111 num
= pack_revindex_ix(p
);
113 pack_revindex
[num
].p
= p
;
115 /* revindex elements are lazily initialized */
118 static int cmp_offset(const void *a_
, const void *b_
)
120 unsigned long a
= *(unsigned long *) a_
;
121 unsigned long b
= *(unsigned long *) b_
;
131 * Ordered list of offsets of objects in the pack.
133 static void prepare_pack_revindex(struct pack_revindex
*rix
)
135 struct packed_git
*p
= rix
->p
;
136 int num_ent
= num_packed_objects(p
);
138 void *index
= p
->index_base
+ 256;
140 rix
->revindex
= xmalloc(sizeof(unsigned long) * (num_ent
+ 1));
141 for (i
= 0; i
< num_ent
; i
++) {
142 long hl
= *((long *)(index
+ 24 * i
));
143 rix
->revindex
[i
] = ntohl(hl
);
145 /* This knows the pack format -- the 20-byte trailer
146 * follows immediately after the last object data.
148 rix
->revindex
[num_ent
] = p
->pack_size
- 20;
149 qsort(rix
->revindex
, num_ent
, sizeof(unsigned long), cmp_offset
);
152 static unsigned long find_packed_object_size(struct packed_git
*p
,
157 struct pack_revindex
*rix
;
158 unsigned long *revindex
;
159 num
= pack_revindex_ix(p
);
161 die("internal error: pack revindex uninitialized");
162 rix
= &pack_revindex
[num
];
164 prepare_pack_revindex(rix
);
165 revindex
= rix
->revindex
;
167 hi
= num_packed_objects(p
) + 1;
169 int mi
= (lo
+ hi
) / 2;
170 if (revindex
[mi
] == ofs
) {
171 return revindex
[mi
+1] - ofs
;
173 else if (ofs
< revindex
[mi
])
178 die("internal error: pack revindex corrupt");
181 static void *delta_against(void *buf
, unsigned long size
, struct object_entry
*entry
)
183 unsigned long othersize
, delta_size
;
185 void *otherbuf
= read_sha1_file(entry
->delta
->sha1
, type
, &othersize
);
189 die("unable to read %s", sha1_to_hex(entry
->delta
->sha1
));
190 delta_buf
= diff_delta(otherbuf
, othersize
,
191 buf
, size
, &delta_size
, 0);
192 if (!delta_buf
|| delta_size
!= entry
->delta_size
)
193 die("delta size changed");
200 * The per-object header is a pretty dense thing, which is
201 * - first byte: low four bits are "size", then three bits of "type",
202 * and the high bit is "size continues".
203 * - each byte afterwards: low seven bits are size continuation,
204 * with the high bit being "size continues"
206 static int encode_header(enum object_type type
, unsigned long size
, unsigned char *hdr
)
211 if (type
< OBJ_COMMIT
|| type
> OBJ_DELTA
)
212 die("bad type %d", type
);
214 c
= (type
<< 4) | (size
& 15);
226 static unsigned long write_object(struct sha1file
*f
, struct object_entry
*entry
)
231 unsigned char header
[10];
232 unsigned hdrlen
, datalen
;
233 enum object_type obj_type
;
236 obj_type
= entry
->type
;
237 if (! entry
->in_pack
)
238 to_reuse
= 0; /* can't reuse what we don't have */
239 else if (obj_type
== OBJ_DELTA
)
240 to_reuse
= 1; /* check_object() decided it for us */
241 else if (obj_type
!= entry
->in_pack_type
)
242 to_reuse
= 0; /* pack has delta which is unusable */
243 else if (entry
->delta
)
244 to_reuse
= 0; /* we want to pack afresh */
246 to_reuse
= 1; /* we have it in-pack undeltified,
247 * and we do not need to deltify it.
251 buf
= read_sha1_file(entry
->sha1
, type
, &size
);
253 die("unable to read %s", sha1_to_hex(entry
->sha1
));
254 if (size
!= entry
->size
)
255 die("object %s size inconsistency (%lu vs %lu)",
256 sha1_to_hex(entry
->sha1
), size
, entry
->size
);
258 buf
= delta_against(buf
, size
, entry
);
259 size
= entry
->delta_size
;
260 obj_type
= OBJ_DELTA
;
263 * The object header is a byte of 'type' followed by zero or
264 * more bytes of length. For deltas, the 20 bytes of delta
267 hdrlen
= encode_header(obj_type
, size
, header
);
268 sha1write(f
, header
, hdrlen
);
271 sha1write(f
, entry
->delta
, 20);
274 datalen
= sha1write_compressed(f
, buf
, size
);
278 struct packed_git
*p
= entry
->in_pack
;
281 datalen
= find_packed_object_size(p
, entry
->in_pack_offset
);
282 buf
= p
->pack_base
+ entry
->in_pack_offset
;
283 sha1write(f
, buf
, datalen
);
285 hdrlen
= 0; /* not really */
286 if (obj_type
== OBJ_DELTA
)
290 if (obj_type
== OBJ_DELTA
)
293 return hdrlen
+ datalen
;
296 static unsigned long write_one(struct sha1file
*f
,
297 struct object_entry
*e
,
298 unsigned long offset
)
301 /* offset starts from header size and cannot be zero
302 * if it is written already.
306 offset
+= write_object(f
, e
);
307 /* if we are deltified, write out its base object. */
309 offset
= write_one(f
, e
->delta
, offset
);
313 static void write_pack_file(void)
317 unsigned long offset
;
318 struct pack_header hdr
;
321 f
= sha1fd(1, "<stdout>");
323 f
= sha1create("%s-%s.%s", base_name
, sha1_to_hex(object_list_sha1
), "pack");
324 hdr
.hdr_signature
= htonl(PACK_SIGNATURE
);
325 hdr
.hdr_version
= htonl(PACK_VERSION
);
326 hdr
.hdr_entries
= htonl(nr_objects
);
327 sha1write(f
, &hdr
, sizeof(hdr
));
328 offset
= sizeof(hdr
);
329 for (i
= 0; i
< nr_objects
; i
++)
330 offset
= write_one(f
, objects
+ i
, offset
);
332 sha1close(f
, pack_file_sha1
, 1);
335 static void write_index_file(void)
338 struct sha1file
*f
= sha1create("%s-%s.%s", base_name
, sha1_to_hex(object_list_sha1
), "idx");
339 struct object_entry
**list
= sorted_by_sha
;
340 struct object_entry
**last
= list
+ nr_objects
;
341 unsigned int array
[256];
344 * Write the first-level table (the list is sorted,
345 * but we use a 256-entry lookup to be able to avoid
346 * having to do eight extra binary search iterations).
348 for (i
= 0; i
< 256; i
++) {
349 struct object_entry
**next
= list
;
350 while (next
< last
) {
351 struct object_entry
*entry
= *next
;
352 if (entry
->sha1
[0] != i
)
356 array
[i
] = htonl(next
- sorted_by_sha
);
359 sha1write(f
, array
, 256 * sizeof(int));
362 * Write the actual SHA1 entries..
364 list
= sorted_by_sha
;
365 for (i
= 0; i
< nr_objects
; i
++) {
366 struct object_entry
*entry
= *list
++;
367 unsigned int offset
= htonl(entry
->offset
);
368 sha1write(f
, &offset
, 4);
369 sha1write(f
, entry
->sha1
, 20);
371 sha1write(f
, pack_file_sha1
, 20);
372 sha1close(f
, NULL
, 1);
375 static int add_object_entry(unsigned char *sha1
, unsigned int hash
)
377 unsigned int idx
= nr_objects
;
378 struct object_entry
*entry
;
379 struct packed_git
*p
;
380 unsigned int found_offset
= 0;
381 struct packed_git
*found_pack
= NULL
;
383 for (p
= packed_git
; p
; p
= p
->next
) {
385 if (find_pack_entry_one(sha1
, &e
, p
)) {
388 if (local
&& !p
->pack_local
)
391 found_offset
= e
.offset
;
397 if (idx
>= nr_alloc
) {
398 unsigned int needed
= (idx
+ 1024) * 3 / 2;
399 objects
= xrealloc(objects
, needed
* sizeof(*entry
));
402 entry
= objects
+ idx
;
403 memset(entry
, 0, sizeof(*entry
));
404 memcpy(entry
->sha1
, sha1
, 20);
407 entry
->in_pack
= found_pack
;
408 entry
->in_pack_offset
= found_offset
;
414 static int locate_object_entry_hash(unsigned char *sha1
)
418 memcpy(&ui
, sha1
, sizeof(unsigned int));
419 i
= ui
% object_ix_hashsz
;
420 while (0 < object_ix
[i
]) {
421 if (!memcmp(sha1
, objects
[object_ix
[i
]-1].sha1
, 20))
423 if (++i
== object_ix_hashsz
)
429 static struct object_entry
*locate_object_entry(unsigned char *sha1
)
431 int i
= locate_object_entry_hash(sha1
);
433 return &objects
[object_ix
[i
]-1];
437 static void check_object(struct object_entry
*entry
)
441 if (entry
->in_pack
) {
442 unsigned char base
[20];
444 struct object_entry
*base_entry
;
446 /* We want in_pack_type even if we do not reuse delta.
447 * There is no point not reusing non-delta representations.
449 check_reuse_pack_delta(entry
->in_pack
,
450 entry
->in_pack_offset
,
452 &entry
->in_pack_type
);
454 /* Check if it is delta, and the base is also an object
455 * we are going to pack. If so we will reuse the existing
458 if (!no_reuse_delta
&&
459 entry
->in_pack_type
== OBJ_DELTA
&&
460 (base_entry
= locate_object_entry(base
))) {
462 /* Depth value does not matter - find_deltas()
463 * will never consider reused delta as the
464 * base object to deltify other objects
465 * against, in order to avoid circular deltas.
468 /* uncompressed size of the delta data */
469 entry
->size
= entry
->delta_size
= size
;
470 entry
->delta
= base_entry
;
471 entry
->type
= OBJ_DELTA
;
473 base_entry
->edge
= 1;
477 /* Otherwise we would do the usual */
480 if (sha1_object_info(entry
->sha1
, type
, &entry
->size
))
481 die("unable to get type of object %s",
482 sha1_to_hex(entry
->sha1
));
484 if (!strcmp(type
, "commit")) {
485 entry
->type
= OBJ_COMMIT
;
486 } else if (!strcmp(type
, "tree")) {
487 entry
->type
= OBJ_TREE
;
488 } else if (!strcmp(type
, "blob")) {
489 entry
->type
= OBJ_BLOB
;
490 } else if (!strcmp(type
, "tag")) {
491 entry
->type
= OBJ_TAG
;
493 die("unable to pack object %s of type %s",
494 sha1_to_hex(entry
->sha1
), type
);
497 static void hash_objects(void)
500 struct object_entry
*oe
;
502 object_ix_hashsz
= nr_objects
* 2;
503 object_ix
= xcalloc(sizeof(int), object_ix_hashsz
);
504 for (i
= 0, oe
= objects
; i
< nr_objects
; i
++, oe
++) {
505 int ix
= locate_object_entry_hash(oe
->sha1
);
507 error("the same object '%s' added twice",
508 sha1_to_hex(oe
->sha1
));
512 object_ix
[ix
] = i
+ 1;
516 static void get_object_details(void)
519 struct object_entry
*entry
= objects
;
523 for (i
= 0; i
< nr_objects
; i
++)
524 check_object(entry
++);
527 typedef int (*entry_sort_t
)(const struct object_entry
*, const struct object_entry
*);
529 static entry_sort_t current_sort
;
531 static int sort_comparator(const void *_a
, const void *_b
)
533 struct object_entry
*a
= *(struct object_entry
**)_a
;
534 struct object_entry
*b
= *(struct object_entry
**)_b
;
535 return current_sort(a
,b
);
538 static struct object_entry
**create_sorted_list(entry_sort_t sort
)
540 struct object_entry
**list
= xmalloc(nr_objects
* sizeof(struct object_entry
*));
543 for (i
= 0; i
< nr_objects
; i
++)
544 list
[i
] = objects
+ i
;
546 qsort(list
, nr_objects
, sizeof(struct object_entry
*), sort_comparator
);
550 static int sha1_sort(const struct object_entry
*a
, const struct object_entry
*b
)
552 return memcmp(a
->sha1
, b
->sha1
, 20);
555 static int type_size_sort(const struct object_entry
*a
, const struct object_entry
*b
)
557 if (a
->type
< b
->type
)
559 if (a
->type
> b
->type
)
561 if (a
->hash
< b
->hash
)
563 if (a
->hash
> b
->hash
)
565 if (a
->size
< b
->size
)
567 if (a
->size
> b
->size
)
569 return a
< b
? -1 : (a
> b
);
573 struct object_entry
*entry
;
578 * We search for deltas _backwards_ in a list sorted by type and
579 * by size, so that we see progressively smaller and smaller files.
580 * That's because we prefer deltas to be from the bigger file
581 * to the smaller - deletes are potentially cheaper, but perhaps
582 * more importantly, the bigger file is likely the more recent
585 static int try_delta(struct unpacked
*cur
, struct unpacked
*old
, unsigned max_depth
)
587 struct object_entry
*cur_entry
= cur
->entry
;
588 struct object_entry
*old_entry
= old
->entry
;
589 unsigned long size
, oldsize
, delta_size
, sizediff
;
593 /* Don't bother doing diffs between different types */
594 if (cur_entry
->type
!= old_entry
->type
)
597 /* If the current object is at edge, take the depth the objects
598 * that depend on the current object into account -- otherwise
599 * they would become too deep.
604 size
= cur_entry
->size
;
607 oldsize
= old_entry
->size
;
608 sizediff
= oldsize
> size
? oldsize
- size
: size
- oldsize
;
609 if (sizediff
> size
/ 8)
611 if (old_entry
->depth
>= max_depth
)
617 * We always delta from the bigger to the smaller, since that's
618 * more space-efficient (deletes don't have to say _what_ they
621 max_size
= size
/ 2 - 20;
622 if (cur_entry
->delta
)
623 max_size
= cur_entry
->delta_size
-1;
624 if (sizediff
>= max_size
)
626 delta_buf
= diff_delta(old
->data
, oldsize
,
627 cur
->data
, size
, &delta_size
, max_size
);
630 cur_entry
->delta
= old_entry
;
631 cur_entry
->delta_size
= delta_size
;
632 cur_entry
->depth
= old_entry
->depth
+ 1;
637 static void find_deltas(struct object_entry
**list
, int window
, int depth
)
640 unsigned int array_size
= window
* sizeof(struct unpacked
);
641 struct unpacked
*array
= xmalloc(array_size
);
644 memset(array
, 0, array_size
);
647 eye_candy
= i
- (nr_objects
/ 20);
650 struct object_entry
*entry
= list
[i
];
651 struct unpacked
*n
= array
+ idx
;
656 if (progress
&& i
<= eye_candy
) {
657 eye_candy
-= nr_objects
/ 20;
662 /* This happens if we decided to reuse existing
663 * delta from a pack. "!no_reuse_delta &&" is implied.
669 n
->data
= read_sha1_file(entry
->sha1
, type
, &size
);
670 if (size
!= entry
->size
)
671 die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry
->sha1
), size
, entry
->size
);
675 unsigned int other_idx
= idx
+ j
;
677 if (other_idx
>= window
)
679 m
= array
+ other_idx
;
682 if (try_delta(n
, m
, depth
) < 0)
690 for (i
= 0; i
< window
; ++i
)
695 static void prepare_pack(int window
, int depth
)
698 fprintf(stderr
, "Packing %d objects", nr_objects
);
699 get_object_details();
703 sorted_by_type
= create_sorted_list(type_size_sort
);
705 find_deltas(sorted_by_type
, window
+1, depth
);
711 static int reuse_cached_pack(unsigned char *sha1
, int pack_to_stdout
)
713 static const char cache
[] = "pack-cache/pack-%s.%s";
714 char *cached_pack
, *cached_idx
;
715 int ifd
, ofd
, ifd_ix
= -1;
717 cached_pack
= git_path(cache
, sha1_to_hex(sha1
), "pack");
718 ifd
= open(cached_pack
, O_RDONLY
);
722 if (!pack_to_stdout
) {
723 cached_idx
= git_path(cache
, sha1_to_hex(sha1
), "idx");
724 ifd_ix
= open(cached_idx
, O_RDONLY
);
732 fprintf(stderr
, "Reusing %d objects pack %s\n", nr_objects
,
735 if (pack_to_stdout
) {
742 snprintf(name
, sizeof(name
),
743 "%s-%s.%s", base_name
, sha1_to_hex(sha1
), "pack");
744 ofd
= open(name
, O_CREAT
| O_EXCL
| O_WRONLY
, 0666);
746 die("unable to open %s (%s)", name
, strerror(errno
));
747 if (copy_fd(ifd
, ofd
))
751 snprintf(name
, sizeof(name
),
752 "%s-%s.%s", base_name
, sha1_to_hex(sha1
), "idx");
753 ofd
= open(name
, O_CREAT
| O_EXCL
| O_WRONLY
, 0666);
755 die("unable to open %s (%s)", name
, strerror(errno
));
756 if (copy_fd(ifd_ix
, ofd
))
759 puts(sha1_to_hex(sha1
));
765 int main(int argc
, char **argv
)
768 char line
[PATH_MAX
+ 20];
769 int window
= 10, depth
= 10, pack_to_stdout
= 0;
770 struct object_entry
**list
;
772 struct timeval prev_tv
;
774 int eye_candy_incr
= 500;
777 setup_git_directory();
779 for (i
= 1; i
< argc
; i
++) {
780 const char *arg
= argv
[i
];
783 if (!strcmp("--non-empty", arg
)) {
787 if (!strcmp("--local", arg
)) {
791 if (!strcmp("--incremental", arg
)) {
795 if (!strncmp("--window=", arg
, 9)) {
797 window
= strtoul(arg
+9, &end
, 0);
802 if (!strncmp("--depth=", arg
, 8)) {
804 depth
= strtoul(arg
+8, &end
, 0);
809 if (!strcmp("-q", arg
)) {
813 if (!strcmp("--no-reuse-delta", arg
)) {
817 if (!strcmp("--stdout", arg
)) {
828 if (pack_to_stdout
!= !base_name
)
831 prepare_packed_git();
833 fprintf(stderr
, "Generating pack...\n");
834 gettimeofday(&prev_tv
, NULL
);
836 while (fgets(line
, sizeof(line
), stdin
) != NULL
) {
839 unsigned char sha1
[20];
841 if (progress
&& (eye_candy
<= nr_objects
)) {
842 fprintf(stderr
, "Counting objects...%d\r", nr_objects
);
843 if (eye_candy
&& (50 <= eye_candy_incr
)) {
846 gettimeofday(&tv
, NULL
);
847 time_diff
= (tv
.tv_sec
- prev_tv
.tv_sec
);
849 time_diff
+= (tv
.tv_usec
- prev_tv
.tv_usec
);
850 if ((1 << 9) < time_diff
)
851 eye_candy_incr
+= 50;
852 else if (50 < eye_candy_incr
)
853 eye_candy_incr
-= 50;
855 eye_candy
+= eye_candy_incr
;
857 if (get_sha1_hex(line
, sha1
))
858 die("expected sha1, got garbage:\n %s", line
);
862 unsigned char c
= *p
++;
865 hash
= hash
* 11 + c
;
867 add_object_entry(sha1
, hash
);
870 fprintf(stderr
, "Done counting %d objects.\n", nr_objects
);
871 if (non_empty
&& !nr_objects
)
874 sorted_by_sha
= create_sorted_list(sha1_sort
);
876 list
= sorted_by_sha
;
877 for (i
= 0; i
< nr_objects
; i
++) {
878 struct object_entry
*entry
= *list
++;
879 SHA1_Update(&ctx
, entry
->sha1
, 20);
881 SHA1_Final(object_list_sha1
, &ctx
);
883 if (reuse_cached_pack(object_list_sha1
, pack_to_stdout
))
886 prepare_pack(window
, depth
);
887 if (!pack_to_stdout
) {
889 puts(sha1_to_hex(object_list_sha1
));
893 fprintf(stderr
, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
894 nr_objects
, written
, written_delta
, reused
, reused_delta
);