Merge branch 'sg/completion'
[git] / builtin / index-pack.c
1 #include "cache.h"
2 #include "delta.h"
3 #include "pack.h"
4 #include "csum-file.h"
5 #include "blob.h"
6 #include "commit.h"
7 #include "tag.h"
8 #include "tree.h"
9 #include "progress.h"
10 #include "fsck.h"
11 #include "exec_cmd.h"
12
13 static const char index_pack_usage[] =
14 "git index-pack [-v] [-o <index-file>] [ --keep | --keep=<msg> ] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
15
16 struct object_entry
17 {
18         struct pack_idx_entry idx;
19         unsigned long size;
20         unsigned int hdr_size;
21         enum object_type type;
22         enum object_type real_type;
23 };
24
25 union delta_base {
26         unsigned char sha1[20];
27         off_t offset;
28 };
29
30 struct base_data {
31         struct base_data *base;
32         struct base_data *child;
33         struct object_entry *obj;
34         void *data;
35         unsigned long size;
36 };
37
38 /*
39  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
40  * to memcmp() only the first 20 bytes.
41  */
42 #define UNION_BASE_SZ   20
43
44 #define FLAG_LINK (1u<<20)
45 #define FLAG_CHECKED (1u<<21)
46
47 struct delta_entry
48 {
49         union delta_base base;
50         int obj_no;
51 };
52
53 static struct object_entry *objects;
54 static struct delta_entry *deltas;
55 static struct base_data *base_cache;
56 static size_t base_cache_used;
57 static int nr_objects;
58 static int nr_deltas;
59 static int nr_resolved_deltas;
60
61 static int from_stdin;
62 static int strict;
63 static int verbose;
64
65 static struct progress *progress;
66
67 /* We always read in 4kB chunks. */
68 static unsigned char input_buffer[4096];
69 static unsigned int input_offset, input_len;
70 static off_t consumed_bytes;
71 static git_SHA_CTX input_ctx;
72 static uint32_t input_crc32;
73 static int input_fd, output_fd, pack_fd;
74
75 static int mark_link(struct object *obj, int type, void *data)
76 {
77         if (!obj)
78                 return -1;
79
80         if (type != OBJ_ANY && obj->type != type)
81                 die("object type mismatch at %s", sha1_to_hex(obj->sha1));
82
83         obj->flags |= FLAG_LINK;
84         return 0;
85 }
86
87 /* The content of each linked object must have been checked
88    or it must be already present in the object database */
89 static void check_object(struct object *obj)
90 {
91         if (!obj)
92                 return;
93
94         if (!(obj->flags & FLAG_LINK))
95                 return;
96
97         if (!(obj->flags & FLAG_CHECKED)) {
98                 unsigned long size;
99                 int type = sha1_object_info(obj->sha1, &size);
100                 if (type != obj->type || type <= 0)
101                         die("object of unexpected type");
102                 obj->flags |= FLAG_CHECKED;
103                 return;
104         }
105 }
106
107 static void check_objects(void)
108 {
109         unsigned i, max;
110
111         max = get_max_object_index();
112         for (i = 0; i < max; i++)
113                 check_object(get_indexed_object(i));
114 }
115
116
117 /* Discard current buffer used content. */
118 static void flush(void)
119 {
120         if (input_offset) {
121                 if (output_fd >= 0)
122                         write_or_die(output_fd, input_buffer, input_offset);
123                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
124                 memmove(input_buffer, input_buffer + input_offset, input_len);
125                 input_offset = 0;
126         }
127 }
128
129 /*
130  * Make sure at least "min" bytes are available in the buffer, and
131  * return the pointer to the buffer.
132  */
133 static void *fill(int min)
134 {
135         if (min <= input_len)
136                 return input_buffer + input_offset;
137         if (min > sizeof(input_buffer))
138                 die("cannot fill %d bytes", min);
139         flush();
140         do {
141                 ssize_t ret = xread(input_fd, input_buffer + input_len,
142                                 sizeof(input_buffer) - input_len);
143                 if (ret <= 0) {
144                         if (!ret)
145                                 die("early EOF");
146                         die_errno("read error on input");
147                 }
148                 input_len += ret;
149                 if (from_stdin)
150                         display_throughput(progress, consumed_bytes + input_len);
151         } while (input_len < min);
152         return input_buffer;
153 }
154
155 static void use(int bytes)
156 {
157         if (bytes > input_len)
158                 die("used more bytes than were available");
159         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
160         input_len -= bytes;
161         input_offset += bytes;
162
163         /* make sure off_t is sufficiently large not to wrap */
164         if (signed_add_overflows(consumed_bytes, bytes))
165                 die("pack too large for current definition of off_t");
166         consumed_bytes += bytes;
167 }
168
169 static const char *open_pack_file(const char *pack_name)
170 {
171         if (from_stdin) {
172                 input_fd = 0;
173                 if (!pack_name) {
174                         static char tmpfile[PATH_MAX];
175                         output_fd = odb_mkstemp(tmpfile, sizeof(tmpfile),
176                                                 "pack/tmp_pack_XXXXXX");
177                         pack_name = xstrdup(tmpfile);
178                 } else
179                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
180                 if (output_fd < 0)
181                         die_errno("unable to create '%s'", pack_name);
182                 pack_fd = output_fd;
183         } else {
184                 input_fd = open(pack_name, O_RDONLY);
185                 if (input_fd < 0)
186                         die_errno("cannot open packfile '%s'", pack_name);
187                 output_fd = -1;
188                 pack_fd = input_fd;
189         }
190         git_SHA1_Init(&input_ctx);
191         return pack_name;
192 }
193
194 static void parse_pack_header(void)
195 {
196         struct pack_header *hdr = fill(sizeof(struct pack_header));
197
198         /* Header consistency check */
199         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
200                 die("pack signature mismatch");
201         if (!pack_version_ok(hdr->hdr_version))
202                 die("pack version %"PRIu32" unsupported",
203                         ntohl(hdr->hdr_version));
204
205         nr_objects = ntohl(hdr->hdr_entries);
206         use(sizeof(struct pack_header));
207 }
208
209 static NORETURN void bad_object(unsigned long offset, const char *format,
210                        ...) __attribute__((format (printf, 2, 3)));
211
212 static void bad_object(unsigned long offset, const char *format, ...)
213 {
214         va_list params;
215         char buf[1024];
216
217         va_start(params, format);
218         vsnprintf(buf, sizeof(buf), format, params);
219         va_end(params);
220         die("pack has bad object at offset %lu: %s", offset, buf);
221 }
222
223 static void free_base_data(struct base_data *c)
224 {
225         if (c->data) {
226                 free(c->data);
227                 c->data = NULL;
228                 base_cache_used -= c->size;
229         }
230 }
231
232 static void prune_base_data(struct base_data *retain)
233 {
234         struct base_data *b;
235         for (b = base_cache;
236              base_cache_used > delta_base_cache_limit && b;
237              b = b->child) {
238                 if (b->data && b != retain)
239                         free_base_data(b);
240         }
241 }
242
243 static void link_base_data(struct base_data *base, struct base_data *c)
244 {
245         if (base)
246                 base->child = c;
247         else
248                 base_cache = c;
249
250         c->base = base;
251         c->child = NULL;
252         if (c->data)
253                 base_cache_used += c->size;
254         prune_base_data(c);
255 }
256
257 static void unlink_base_data(struct base_data *c)
258 {
259         struct base_data *base = c->base;
260         if (base)
261                 base->child = NULL;
262         else
263                 base_cache = NULL;
264         free_base_data(c);
265 }
266
267 static void *unpack_entry_data(unsigned long offset, unsigned long size)
268 {
269         int status;
270         z_stream stream;
271         void *buf = xmalloc(size);
272
273         memset(&stream, 0, sizeof(stream));
274         git_inflate_init(&stream);
275         stream.next_out = buf;
276         stream.avail_out = size;
277
278         do {
279                 stream.next_in = fill(1);
280                 stream.avail_in = input_len;
281                 status = git_inflate(&stream, 0);
282                 use(input_len - stream.avail_in);
283         } while (status == Z_OK);
284         if (stream.total_out != size || status != Z_STREAM_END)
285                 bad_object(offset, "inflate returned %d", status);
286         git_inflate_end(&stream);
287         return buf;
288 }
289
290 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
291 {
292         unsigned char *p;
293         unsigned long size, c;
294         off_t base_offset;
295         unsigned shift;
296         void *data;
297
298         obj->idx.offset = consumed_bytes;
299         input_crc32 = crc32(0, Z_NULL, 0);
300
301         p = fill(1);
302         c = *p;
303         use(1);
304         obj->type = (c >> 4) & 7;
305         size = (c & 15);
306         shift = 4;
307         while (c & 0x80) {
308                 p = fill(1);
309                 c = *p;
310                 use(1);
311                 size += (c & 0x7f) << shift;
312                 shift += 7;
313         }
314         obj->size = size;
315
316         switch (obj->type) {
317         case OBJ_REF_DELTA:
318                 hashcpy(delta_base->sha1, fill(20));
319                 use(20);
320                 break;
321         case OBJ_OFS_DELTA:
322                 memset(delta_base, 0, sizeof(*delta_base));
323                 p = fill(1);
324                 c = *p;
325                 use(1);
326                 base_offset = c & 127;
327                 while (c & 128) {
328                         base_offset += 1;
329                         if (!base_offset || MSB(base_offset, 7))
330                                 bad_object(obj->idx.offset, "offset value overflow for delta base object");
331                         p = fill(1);
332                         c = *p;
333                         use(1);
334                         base_offset = (base_offset << 7) + (c & 127);
335                 }
336                 delta_base->offset = obj->idx.offset - base_offset;
337                 if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
338                         bad_object(obj->idx.offset, "delta base offset is out of bound");
339                 break;
340         case OBJ_COMMIT:
341         case OBJ_TREE:
342         case OBJ_BLOB:
343         case OBJ_TAG:
344                 break;
345         default:
346                 bad_object(obj->idx.offset, "unknown object type %d", obj->type);
347         }
348         obj->hdr_size = consumed_bytes - obj->idx.offset;
349
350         data = unpack_entry_data(obj->idx.offset, obj->size);
351         obj->idx.crc32 = input_crc32;
352         return data;
353 }
354
355 static void *get_data_from_pack(struct object_entry *obj)
356 {
357         off_t from = obj[0].idx.offset + obj[0].hdr_size;
358         unsigned long len = obj[1].idx.offset - from;
359         unsigned char *data, *inbuf;
360         z_stream stream;
361         int status;
362
363         data = xmalloc(obj->size);
364         inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
365
366         memset(&stream, 0, sizeof(stream));
367         git_inflate_init(&stream);
368         stream.next_out = data;
369         stream.avail_out = obj->size;
370
371         do {
372                 ssize_t n = (len < 64*1024) ? len : 64*1024;
373                 n = pread(pack_fd, inbuf, n, from);
374                 if (n < 0)
375                         die_errno("cannot pread pack file");
376                 if (!n)
377                         die("premature end of pack file, %lu bytes missing", len);
378                 from += n;
379                 len -= n;
380                 stream.next_in = inbuf;
381                 stream.avail_in = n;
382                 status = git_inflate(&stream, 0);
383         } while (len && status == Z_OK && !stream.avail_in);
384
385         /* This has been inflated OK when first encountered, so... */
386         if (status != Z_STREAM_END || stream.total_out != obj->size)
387                 die("serious inflate inconsistency");
388
389         git_inflate_end(&stream);
390         free(inbuf);
391         return data;
392 }
393
394 static int find_delta(const union delta_base *base)
395 {
396         int first = 0, last = nr_deltas;
397
398         while (first < last) {
399                 int next = (first + last) / 2;
400                 struct delta_entry *delta = &deltas[next];
401                 int cmp;
402
403                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
404                 if (!cmp)
405                         return next;
406                 if (cmp < 0) {
407                         last = next;
408                         continue;
409                 }
410                 first = next+1;
411         }
412         return -first-1;
413 }
414
415 static void find_delta_children(const union delta_base *base,
416                                 int *first_index, int *last_index)
417 {
418         int first = find_delta(base);
419         int last = first;
420         int end = nr_deltas - 1;
421
422         if (first < 0) {
423                 *first_index = 0;
424                 *last_index = -1;
425                 return;
426         }
427         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
428                 --first;
429         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
430                 ++last;
431         *first_index = first;
432         *last_index = last;
433 }
434
435 static void sha1_object(const void *data, unsigned long size,
436                         enum object_type type, unsigned char *sha1)
437 {
438         hash_sha1_file(data, size, typename(type), sha1);
439         if (has_sha1_file(sha1)) {
440                 void *has_data;
441                 enum object_type has_type;
442                 unsigned long has_size;
443                 has_data = read_sha1_file(sha1, &has_type, &has_size);
444                 if (!has_data)
445                         die("cannot read existing object %s", sha1_to_hex(sha1));
446                 if (size != has_size || type != has_type ||
447                     memcmp(data, has_data, size) != 0)
448                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
449                 free(has_data);
450         }
451         if (strict) {
452                 if (type == OBJ_BLOB) {
453                         struct blob *blob = lookup_blob(sha1);
454                         if (blob)
455                                 blob->object.flags |= FLAG_CHECKED;
456                         else
457                                 die("invalid blob object %s", sha1_to_hex(sha1));
458                 } else {
459                         struct object *obj;
460                         int eaten;
461                         void *buf = (void *) data;
462
463                         /*
464                          * we do not need to free the memory here, as the
465                          * buf is deleted by the caller.
466                          */
467                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
468                         if (!obj)
469                                 die("invalid %s", typename(type));
470                         if (fsck_object(obj, 1, fsck_error_function))
471                                 die("Error in object");
472                         if (fsck_walk(obj, mark_link, NULL))
473                                 die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
474
475                         if (obj->type == OBJ_TREE) {
476                                 struct tree *item = (struct tree *) obj;
477                                 item->buffer = NULL;
478                         }
479                         if (obj->type == OBJ_COMMIT) {
480                                 struct commit *commit = (struct commit *) obj;
481                                 commit->buffer = NULL;
482                         }
483                         obj->flags |= FLAG_CHECKED;
484                 }
485         }
486 }
487
488 static void *get_base_data(struct base_data *c)
489 {
490         if (!c->data) {
491                 struct object_entry *obj = c->obj;
492
493                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
494                         void *base = get_base_data(c->base);
495                         void *raw = get_data_from_pack(obj);
496                         c->data = patch_delta(
497                                 base, c->base->size,
498                                 raw, obj->size,
499                                 &c->size);
500                         free(raw);
501                         if (!c->data)
502                                 bad_object(obj->idx.offset, "failed to apply delta");
503                 } else {
504                         c->data = get_data_from_pack(obj);
505                         c->size = obj->size;
506                 }
507
508                 base_cache_used += c->size;
509                 prune_base_data(c);
510         }
511         return c->data;
512 }
513
514 static void resolve_delta(struct object_entry *delta_obj,
515                           struct base_data *base, struct base_data *result)
516 {
517         void *base_data, *delta_data;
518
519         delta_obj->real_type = base->obj->real_type;
520         delta_data = get_data_from_pack(delta_obj);
521         base_data = get_base_data(base);
522         result->obj = delta_obj;
523         result->data = patch_delta(base_data, base->size,
524                                    delta_data, delta_obj->size, &result->size);
525         free(delta_data);
526         if (!result->data)
527                 bad_object(delta_obj->idx.offset, "failed to apply delta");
528         sha1_object(result->data, result->size, delta_obj->real_type,
529                     delta_obj->idx.sha1);
530         nr_resolved_deltas++;
531 }
532
533 static void find_unresolved_deltas(struct base_data *base,
534                                    struct base_data *prev_base)
535 {
536         int i, ref_first, ref_last, ofs_first, ofs_last;
537
538         /*
539          * This is a recursive function. Those brackets should help reducing
540          * stack usage by limiting the scope of the delta_base union.
541          */
542         {
543                 union delta_base base_spec;
544
545                 hashcpy(base_spec.sha1, base->obj->idx.sha1);
546                 find_delta_children(&base_spec, &ref_first, &ref_last);
547
548                 memset(&base_spec, 0, sizeof(base_spec));
549                 base_spec.offset = base->obj->idx.offset;
550                 find_delta_children(&base_spec, &ofs_first, &ofs_last);
551         }
552
553         if (ref_last == -1 && ofs_last == -1) {
554                 free(base->data);
555                 return;
556         }
557
558         link_base_data(prev_base, base);
559
560         for (i = ref_first; i <= ref_last; i++) {
561                 struct object_entry *child = objects + deltas[i].obj_no;
562                 if (child->real_type == OBJ_REF_DELTA) {
563                         struct base_data result;
564                         resolve_delta(child, base, &result);
565                         if (i == ref_last && ofs_last == -1)
566                                 free_base_data(base);
567                         find_unresolved_deltas(&result, base);
568                 }
569         }
570
571         for (i = ofs_first; i <= ofs_last; i++) {
572                 struct object_entry *child = objects + deltas[i].obj_no;
573                 if (child->real_type == OBJ_OFS_DELTA) {
574                         struct base_data result;
575                         resolve_delta(child, base, &result);
576                         if (i == ofs_last)
577                                 free_base_data(base);
578                         find_unresolved_deltas(&result, base);
579                 }
580         }
581
582         unlink_base_data(base);
583 }
584
585 static int compare_delta_entry(const void *a, const void *b)
586 {
587         const struct delta_entry *delta_a = a;
588         const struct delta_entry *delta_b = b;
589         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
590 }
591
592 /* Parse all objects and return the pack content SHA1 hash */
593 static void parse_pack_objects(unsigned char *sha1)
594 {
595         int i;
596         struct delta_entry *delta = deltas;
597         struct stat st;
598
599         /*
600          * First pass:
601          * - find locations of all objects;
602          * - calculate SHA1 of all non-delta objects;
603          * - remember base (SHA1 or offset) for all deltas.
604          */
605         if (verbose)
606                 progress = start_progress(
607                                 from_stdin ? "Receiving objects" : "Indexing objects",
608                                 nr_objects);
609         for (i = 0; i < nr_objects; i++) {
610                 struct object_entry *obj = &objects[i];
611                 void *data = unpack_raw_entry(obj, &delta->base);
612                 obj->real_type = obj->type;
613                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
614                         nr_deltas++;
615                         delta->obj_no = i;
616                         delta++;
617                 } else
618                         sha1_object(data, obj->size, obj->type, obj->idx.sha1);
619                 free(data);
620                 display_progress(progress, i+1);
621         }
622         objects[i].idx.offset = consumed_bytes;
623         stop_progress(&progress);
624
625         /* Check pack integrity */
626         flush();
627         git_SHA1_Final(sha1, &input_ctx);
628         if (hashcmp(fill(20), sha1))
629                 die("pack is corrupted (SHA1 mismatch)");
630         use(20);
631
632         /* If input_fd is a file, we should have reached its end now. */
633         if (fstat(input_fd, &st))
634                 die_errno("cannot fstat packfile");
635         if (S_ISREG(st.st_mode) &&
636                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
637                 die("pack has junk at the end");
638
639         if (!nr_deltas)
640                 return;
641
642         /* Sort deltas by base SHA1/offset for fast searching */
643         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
644               compare_delta_entry);
645
646         /*
647          * Second pass:
648          * - for all non-delta objects, look if it is used as a base for
649          *   deltas;
650          * - if used as a base, uncompress the object and apply all deltas,
651          *   recursively checking if the resulting object is used as a base
652          *   for some more deltas.
653          */
654         if (verbose)
655                 progress = start_progress("Resolving deltas", nr_deltas);
656         for (i = 0; i < nr_objects; i++) {
657                 struct object_entry *obj = &objects[i];
658                 struct base_data base_obj;
659
660                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
661                         continue;
662                 base_obj.obj = obj;
663                 base_obj.data = NULL;
664                 find_unresolved_deltas(&base_obj, NULL);
665                 display_progress(progress, nr_resolved_deltas);
666         }
667 }
668
669 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
670 {
671         z_stream stream;
672         int status;
673         unsigned char outbuf[4096];
674
675         memset(&stream, 0, sizeof(stream));
676         deflateInit(&stream, zlib_compression_level);
677         stream.next_in = in;
678         stream.avail_in = size;
679
680         do {
681                 stream.next_out = outbuf;
682                 stream.avail_out = sizeof(outbuf);
683                 status = deflate(&stream, Z_FINISH);
684                 sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
685         } while (status == Z_OK);
686
687         if (status != Z_STREAM_END)
688                 die("unable to deflate appended object (%d)", status);
689         size = stream.total_out;
690         deflateEnd(&stream);
691         return size;
692 }
693
694 static struct object_entry *append_obj_to_pack(struct sha1file *f,
695                                const unsigned char *sha1, void *buf,
696                                unsigned long size, enum object_type type)
697 {
698         struct object_entry *obj = &objects[nr_objects++];
699         unsigned char header[10];
700         unsigned long s = size;
701         int n = 0;
702         unsigned char c = (type << 4) | (s & 15);
703         s >>= 4;
704         while (s) {
705                 header[n++] = c | 0x80;
706                 c = s & 0x7f;
707                 s >>= 7;
708         }
709         header[n++] = c;
710         crc32_begin(f);
711         sha1write(f, header, n);
712         obj[0].size = size;
713         obj[0].hdr_size = n;
714         obj[0].type = type;
715         obj[0].real_type = type;
716         obj[1].idx.offset = obj[0].idx.offset + n;
717         obj[1].idx.offset += write_compressed(f, buf, size);
718         obj[0].idx.crc32 = crc32_end(f);
719         sha1flush(f);
720         hashcpy(obj->idx.sha1, sha1);
721         return obj;
722 }
723
724 static int delta_pos_compare(const void *_a, const void *_b)
725 {
726         struct delta_entry *a = *(struct delta_entry **)_a;
727         struct delta_entry *b = *(struct delta_entry **)_b;
728         return a->obj_no - b->obj_no;
729 }
730
731 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
732 {
733         struct delta_entry **sorted_by_pos;
734         int i, n = 0;
735
736         /*
737          * Since many unresolved deltas may well be themselves base objects
738          * for more unresolved deltas, we really want to include the
739          * smallest number of base objects that would cover as much delta
740          * as possible by picking the
741          * trunc deltas first, allowing for other deltas to resolve without
742          * additional base objects.  Since most base objects are to be found
743          * before deltas depending on them, a good heuristic is to start
744          * resolving deltas in the same order as their position in the pack.
745          */
746         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
747         for (i = 0; i < nr_deltas; i++) {
748                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
749                         continue;
750                 sorted_by_pos[n++] = &deltas[i];
751         }
752         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
753
754         for (i = 0; i < n; i++) {
755                 struct delta_entry *d = sorted_by_pos[i];
756                 enum object_type type;
757                 struct base_data base_obj;
758
759                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
760                         continue;
761                 base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
762                 if (!base_obj.data)
763                         continue;
764
765                 if (check_sha1_signature(d->base.sha1, base_obj.data,
766                                 base_obj.size, typename(type)))
767                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
768                 base_obj.obj = append_obj_to_pack(f, d->base.sha1,
769                                         base_obj.data, base_obj.size, type);
770                 find_unresolved_deltas(&base_obj, NULL);
771                 display_progress(progress, nr_resolved_deltas);
772         }
773         free(sorted_by_pos);
774 }
775
776 static void final(const char *final_pack_name, const char *curr_pack_name,
777                   const char *final_index_name, const char *curr_index_name,
778                   const char *keep_name, const char *keep_msg,
779                   unsigned char *sha1)
780 {
781         const char *report = "pack";
782         char name[PATH_MAX];
783         int err;
784
785         if (!from_stdin) {
786                 close(input_fd);
787         } else {
788                 fsync_or_die(output_fd, curr_pack_name);
789                 err = close(output_fd);
790                 if (err)
791                         die_errno("error while closing pack file");
792         }
793
794         if (keep_msg) {
795                 int keep_fd, keep_msg_len = strlen(keep_msg);
796
797                 if (!keep_name)
798                         keep_fd = odb_pack_keep(name, sizeof(name), sha1);
799                 else
800                         keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
801
802                 if (keep_fd < 0) {
803                         if (errno != EEXIST)
804                                 die_errno("cannot write keep file '%s'",
805                                           keep_name);
806                 } else {
807                         if (keep_msg_len > 0) {
808                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
809                                 write_or_die(keep_fd, "\n", 1);
810                         }
811                         if (close(keep_fd) != 0)
812                                 die_errno("cannot close written keep file '%s'",
813                                     keep_name);
814                         report = "keep";
815                 }
816         }
817
818         if (final_pack_name != curr_pack_name) {
819                 if (!final_pack_name) {
820                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
821                                  get_object_directory(), sha1_to_hex(sha1));
822                         final_pack_name = name;
823                 }
824                 if (move_temp_to_file(curr_pack_name, final_pack_name))
825                         die("cannot store pack file");
826         } else if (from_stdin)
827                 chmod(final_pack_name, 0444);
828
829         if (final_index_name != curr_index_name) {
830                 if (!final_index_name) {
831                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
832                                  get_object_directory(), sha1_to_hex(sha1));
833                         final_index_name = name;
834                 }
835                 if (move_temp_to_file(curr_index_name, final_index_name))
836                         die("cannot store index file");
837         } else
838                 chmod(final_index_name, 0444);
839
840         if (!from_stdin) {
841                 printf("%s\n", sha1_to_hex(sha1));
842         } else {
843                 char buf[48];
844                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
845                                    report, sha1_to_hex(sha1));
846                 write_or_die(1, buf, len);
847
848                 /*
849                  * Let's just mimic git-unpack-objects here and write
850                  * the last part of the input buffer to stdout.
851                  */
852                 while (input_len) {
853                         err = xwrite(1, input_buffer + input_offset, input_len);
854                         if (err <= 0)
855                                 break;
856                         input_len -= err;
857                         input_offset += err;
858                 }
859         }
860 }
861
862 static int git_index_pack_config(const char *k, const char *v, void *cb)
863 {
864         if (!strcmp(k, "pack.indexversion")) {
865                 pack_idx_default_version = git_config_int(k, v);
866                 if (pack_idx_default_version > 2)
867                         die("bad pack.indexversion=%"PRIu32,
868                                 pack_idx_default_version);
869                 return 0;
870         }
871         return git_default_config(k, v, cb);
872 }
873
874 int cmd_index_pack(int argc, const char **argv, const char *prefix)
875 {
876         int i, fix_thin_pack = 0;
877         const char *curr_pack, *curr_index;
878         const char *index_name = NULL, *pack_name = NULL;
879         const char *keep_name = NULL, *keep_msg = NULL;
880         char *index_name_buf = NULL, *keep_name_buf = NULL;
881         struct pack_idx_entry **idx_objects;
882         unsigned char pack_sha1[20];
883
884         if (argc == 2 && !strcmp(argv[1], "-h"))
885                 usage(index_pack_usage);
886
887         read_replace_refs = 0;
888
889         git_config(git_index_pack_config, NULL);
890         if (prefix && chdir(prefix))
891                 die("Cannot come back to cwd");
892
893         for (i = 1; i < argc; i++) {
894                 const char *arg = argv[i];
895
896                 if (*arg == '-') {
897                         if (!strcmp(arg, "--stdin")) {
898                                 from_stdin = 1;
899                         } else if (!strcmp(arg, "--fix-thin")) {
900                                 fix_thin_pack = 1;
901                         } else if (!strcmp(arg, "--strict")) {
902                                 strict = 1;
903                         } else if (!strcmp(arg, "--keep")) {
904                                 keep_msg = "";
905                         } else if (!prefixcmp(arg, "--keep=")) {
906                                 keep_msg = arg + 7;
907                         } else if (!prefixcmp(arg, "--pack_header=")) {
908                                 struct pack_header *hdr;
909                                 char *c;
910
911                                 hdr = (struct pack_header *)input_buffer;
912                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
913                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
914                                 if (*c != ',')
915                                         die("bad %s", arg);
916                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
917                                 if (*c)
918                                         die("bad %s", arg);
919                                 input_len = sizeof(*hdr);
920                         } else if (!strcmp(arg, "-v")) {
921                                 verbose = 1;
922                         } else if (!strcmp(arg, "-o")) {
923                                 if (index_name || (i+1) >= argc)
924                                         usage(index_pack_usage);
925                                 index_name = argv[++i];
926                         } else if (!prefixcmp(arg, "--index-version=")) {
927                                 char *c;
928                                 pack_idx_default_version = strtoul(arg + 16, &c, 10);
929                                 if (pack_idx_default_version > 2)
930                                         die("bad %s", arg);
931                                 if (*c == ',')
932                                         pack_idx_off32_limit = strtoul(c+1, &c, 0);
933                                 if (*c || pack_idx_off32_limit & 0x80000000)
934                                         die("bad %s", arg);
935                         } else
936                                 usage(index_pack_usage);
937                         continue;
938                 }
939
940                 if (pack_name)
941                         usage(index_pack_usage);
942                 pack_name = arg;
943         }
944
945         if (!pack_name && !from_stdin)
946                 usage(index_pack_usage);
947         if (fix_thin_pack && !from_stdin)
948                 die("--fix-thin cannot be used without --stdin");
949         if (!index_name && pack_name) {
950                 int len = strlen(pack_name);
951                 if (!has_extension(pack_name, ".pack"))
952                         die("packfile name '%s' does not end with '.pack'",
953                             pack_name);
954                 index_name_buf = xmalloc(len);
955                 memcpy(index_name_buf, pack_name, len - 5);
956                 strcpy(index_name_buf + len - 5, ".idx");
957                 index_name = index_name_buf;
958         }
959         if (keep_msg && !keep_name && pack_name) {
960                 int len = strlen(pack_name);
961                 if (!has_extension(pack_name, ".pack"))
962                         die("packfile name '%s' does not end with '.pack'",
963                             pack_name);
964                 keep_name_buf = xmalloc(len);
965                 memcpy(keep_name_buf, pack_name, len - 5);
966                 strcpy(keep_name_buf + len - 5, ".keep");
967                 keep_name = keep_name_buf;
968         }
969
970         curr_pack = open_pack_file(pack_name);
971         parse_pack_header();
972         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
973         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
974         parse_pack_objects(pack_sha1);
975         if (nr_deltas == nr_resolved_deltas) {
976                 stop_progress(&progress);
977                 /* Flush remaining pack final 20-byte SHA1. */
978                 flush();
979         } else {
980                 if (fix_thin_pack) {
981                         struct sha1file *f;
982                         unsigned char read_sha1[20], tail_sha1[20];
983                         char msg[48];
984                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
985                         int nr_objects_initial = nr_objects;
986                         if (nr_unresolved <= 0)
987                                 die("confusion beyond insanity");
988                         objects = xrealloc(objects,
989                                            (nr_objects + nr_unresolved + 1)
990                                            * sizeof(*objects));
991                         f = sha1fd(output_fd, curr_pack);
992                         fix_unresolved_deltas(f, nr_unresolved);
993                         sprintf(msg, "completed with %d local objects",
994                                 nr_objects - nr_objects_initial);
995                         stop_progress_msg(&progress, msg);
996                         sha1close(f, tail_sha1, 0);
997                         hashcpy(read_sha1, pack_sha1);
998                         fixup_pack_header_footer(output_fd, pack_sha1,
999                                                  curr_pack, nr_objects,
1000                                                  read_sha1, consumed_bytes-20);
1001                         if (hashcmp(read_sha1, tail_sha1) != 0)
1002                                 die("Unexpected tail checksum for %s "
1003                                     "(disk corruption?)", curr_pack);
1004                 }
1005                 if (nr_deltas != nr_resolved_deltas)
1006                         die("pack has %d unresolved deltas",
1007                             nr_deltas - nr_resolved_deltas);
1008         }
1009         free(deltas);
1010         if (strict)
1011                 check_objects();
1012
1013         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1014         for (i = 0; i < nr_objects; i++)
1015                 idx_objects[i] = &objects[i].idx;
1016         curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
1017         free(idx_objects);
1018
1019         final(pack_name, curr_pack,
1020                 index_name, curr_index,
1021                 keep_name, keep_msg,
1022                 pack_sha1);
1023         free(objects);
1024         free(index_name_buf);
1025         free(keep_name_buf);
1026         if (pack_name == NULL)
1027                 free((void *) curr_pack);
1028         if (index_name == NULL)
1029                 free((void *) curr_index);
1030
1031         return 0;
1032 }