Merge branch 'maint'
[git] / 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
10 static const char index_pack_usage[] =
11 "git-index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
12
13 struct object_entry
14 {
15         unsigned long offset;
16         unsigned long size;
17         unsigned int hdr_size;
18         enum object_type type;
19         enum object_type real_type;
20         unsigned char sha1[20];
21 };
22
23 union delta_base {
24         unsigned char sha1[20];
25         unsigned long offset;
26 };
27
28 /*
29  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
30  * to memcmp() only the first 20 bytes.
31  */
32 #define UNION_BASE_SZ   20
33
34 struct delta_entry
35 {
36         union delta_base base;
37         int obj_no;
38 };
39
40 static struct object_entry *objects;
41 static struct delta_entry *deltas;
42 static int nr_objects;
43 static int nr_deltas;
44 static int nr_resolved_deltas;
45
46 static int from_stdin;
47 static int verbose;
48
49 static volatile sig_atomic_t progress_update;
50
51 static void progress_interval(int signum)
52 {
53         progress_update = 1;
54 }
55
56 static void setup_progress_signal(void)
57 {
58         struct sigaction sa;
59         struct itimerval v;
60
61         memset(&sa, 0, sizeof(sa));
62         sa.sa_handler = progress_interval;
63         sigemptyset(&sa.sa_mask);
64         sa.sa_flags = SA_RESTART;
65         sigaction(SIGALRM, &sa, NULL);
66
67         v.it_interval.tv_sec = 1;
68         v.it_interval.tv_usec = 0;
69         v.it_value = v.it_interval;
70         setitimer(ITIMER_REAL, &v, NULL);
71
72 }
73
74 static unsigned display_progress(unsigned n, unsigned total, unsigned last_pc)
75 {
76         unsigned percent = n * 100 / total;
77         if (percent != last_pc || progress_update) {
78                 fprintf(stderr, "%4u%% (%u/%u) done\r", percent, n, total);
79                 progress_update = 0;
80         }
81         return percent;
82 }
83
84 /* We always read in 4kB chunks. */
85 static unsigned char input_buffer[4096];
86 static unsigned long input_offset, input_len, consumed_bytes;
87 static SHA_CTX input_ctx;
88 static int input_fd, output_fd, pack_fd;
89
90 /* Discard current buffer used content. */
91 static void flush(void)
92 {
93         if (input_offset) {
94                 if (output_fd >= 0)
95                         write_or_die(output_fd, input_buffer, input_offset);
96                 SHA1_Update(&input_ctx, input_buffer, input_offset);
97                 memmove(input_buffer, input_buffer + input_offset, input_len);
98                 input_offset = 0;
99         }
100 }
101
102 /*
103  * Make sure at least "min" bytes are available in the buffer, and
104  * return the pointer to the buffer.
105  */
106 static void *fill(int min)
107 {
108         if (min <= input_len)
109                 return input_buffer + input_offset;
110         if (min > sizeof(input_buffer))
111                 die("cannot fill %d bytes", min);
112         flush();
113         do {
114                 int ret = xread(input_fd, input_buffer + input_len,
115                                 sizeof(input_buffer) - input_len);
116                 if (ret <= 0) {
117                         if (!ret)
118                                 die("early EOF");
119                         die("read error on input: %s", strerror(errno));
120                 }
121                 input_len += ret;
122         } while (input_len < min);
123         return input_buffer;
124 }
125
126 static void use(int bytes)
127 {
128         if (bytes > input_len)
129                 die("used more bytes than were available");
130         input_len -= bytes;
131         input_offset += bytes;
132         consumed_bytes += bytes;
133 }
134
135 static const char *open_pack_file(const char *pack_name)
136 {
137         if (from_stdin) {
138                 input_fd = 0;
139                 if (!pack_name) {
140                         static char tmpfile[PATH_MAX];
141                         snprintf(tmpfile, sizeof(tmpfile),
142                                  "%s/tmp_pack_XXXXXX", get_object_directory());
143                         output_fd = mkstemp(tmpfile);
144                         pack_name = xstrdup(tmpfile);
145                 } else
146                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
147                 if (output_fd < 0)
148                         die("unable to create %s: %s\n", pack_name, strerror(errno));
149                 pack_fd = output_fd;
150         } else {
151                 input_fd = open(pack_name, O_RDONLY);
152                 if (input_fd < 0)
153                         die("cannot open packfile '%s': %s",
154                             pack_name, strerror(errno));
155                 output_fd = -1;
156                 pack_fd = input_fd;
157         }
158         SHA1_Init(&input_ctx);
159         return pack_name;
160 }
161
162 static void parse_pack_header(void)
163 {
164         struct pack_header *hdr = fill(sizeof(struct pack_header));
165
166         /* Header consistency check */
167         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
168                 die("pack signature mismatch");
169         if (!pack_version_ok(hdr->hdr_version))
170                 die("pack version %d unsupported", ntohl(hdr->hdr_version));
171
172         nr_objects = ntohl(hdr->hdr_entries);
173         use(sizeof(struct pack_header));
174 }
175
176 static void bad_object(unsigned long offset, const char *format,
177                        ...) NORETURN __attribute__((format (printf, 2, 3)));
178
179 static void bad_object(unsigned long offset, const char *format, ...)
180 {
181         va_list params;
182         char buf[1024];
183
184         va_start(params, format);
185         vsnprintf(buf, sizeof(buf), format, params);
186         va_end(params);
187         die("pack has bad object at offset %lu: %s", offset, buf);
188 }
189
190 static void *unpack_entry_data(unsigned long offset, unsigned long size)
191 {
192         z_stream stream;
193         void *buf = xmalloc(size);
194
195         memset(&stream, 0, sizeof(stream));
196         stream.next_out = buf;
197         stream.avail_out = size;
198         stream.next_in = fill(1);
199         stream.avail_in = input_len;
200         inflateInit(&stream);
201
202         for (;;) {
203                 int ret = inflate(&stream, 0);
204                 use(input_len - stream.avail_in);
205                 if (stream.total_out == size && ret == Z_STREAM_END)
206                         break;
207                 if (ret != Z_OK)
208                         bad_object(offset, "inflate returned %d", ret);
209                 stream.next_in = fill(1);
210                 stream.avail_in = input_len;
211         }
212         inflateEnd(&stream);
213         return buf;
214 }
215
216 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
217 {
218         unsigned char *p, c;
219         unsigned long size, base_offset;
220         unsigned shift;
221
222         obj->offset = consumed_bytes;
223
224         p = fill(1);
225         c = *p;
226         use(1);
227         obj->type = (c >> 4) & 7;
228         size = (c & 15);
229         shift = 4;
230         while (c & 0x80) {
231                 p = fill(1);
232                 c = *p;
233                 use(1);
234                 size += (c & 0x7fUL) << shift;
235                 shift += 7;
236         }
237         obj->size = size;
238
239         switch (obj->type) {
240         case OBJ_REF_DELTA:
241                 hashcpy(delta_base->sha1, fill(20));
242                 use(20);
243                 break;
244         case OBJ_OFS_DELTA:
245                 memset(delta_base, 0, sizeof(*delta_base));
246                 p = fill(1);
247                 c = *p;
248                 use(1);
249                 base_offset = c & 127;
250                 while (c & 128) {
251                         base_offset += 1;
252                         if (!base_offset || base_offset & ~(~0UL >> 7))
253                                 bad_object(obj->offset, "offset value overflow for delta base object");
254                         p = fill(1);
255                         c = *p;
256                         use(1);
257                         base_offset = (base_offset << 7) + (c & 127);
258                 }
259                 delta_base->offset = obj->offset - base_offset;
260                 if (delta_base->offset >= obj->offset)
261                         bad_object(obj->offset, "delta base offset is out of bound");
262                 break;
263         case OBJ_COMMIT:
264         case OBJ_TREE:
265         case OBJ_BLOB:
266         case OBJ_TAG:
267                 break;
268         default:
269                 bad_object(obj->offset, "unknown object type %d", obj->type);
270         }
271         obj->hdr_size = consumed_bytes - obj->offset;
272
273         return unpack_entry_data(obj->offset, obj->size);
274 }
275
276 static void *get_data_from_pack(struct object_entry *obj)
277 {
278         unsigned long from = obj[0].offset + obj[0].hdr_size;
279         unsigned long len = obj[1].offset - from;
280         unsigned long rdy = 0;
281         unsigned char *src, *data;
282         z_stream stream;
283         int st;
284
285         src = xmalloc(len);
286         data = src;
287         do {
288                 ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
289                 if (n <= 0)
290                         die("cannot pread pack file: %s", strerror(errno));
291                 rdy += n;
292         } while (rdy < len);
293         data = xmalloc(obj->size);
294         memset(&stream, 0, sizeof(stream));
295         stream.next_out = data;
296         stream.avail_out = obj->size;
297         stream.next_in = src;
298         stream.avail_in = len;
299         inflateInit(&stream);
300         while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
301         inflateEnd(&stream);
302         if (st != Z_STREAM_END || stream.total_out != obj->size)
303                 die("serious inflate inconsistency");
304         free(src);
305         return data;
306 }
307
308 static int find_delta(const union delta_base *base)
309 {
310         int first = 0, last = nr_deltas;
311
312         while (first < last) {
313                 int next = (first + last) / 2;
314                 struct delta_entry *delta = &deltas[next];
315                 int cmp;
316
317                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
318                 if (!cmp)
319                         return next;
320                 if (cmp < 0) {
321                         last = next;
322                         continue;
323                 }
324                 first = next+1;
325         }
326         return -first-1;
327 }
328
329 static int find_delta_children(const union delta_base *base,
330                                int *first_index, int *last_index)
331 {
332         int first = find_delta(base);
333         int last = first;
334         int end = nr_deltas - 1;
335
336         if (first < 0)
337                 return -1;
338         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
339                 --first;
340         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
341                 ++last;
342         *first_index = first;
343         *last_index = last;
344         return 0;
345 }
346
347 static void sha1_object(const void *data, unsigned long size,
348                         enum object_type type, unsigned char *sha1)
349 {
350         hash_sha1_file(data, size, typename(type), sha1);
351         if (has_sha1_file(sha1)) {
352                 void *has_data;
353                 enum object_type has_type;
354                 unsigned long has_size;
355                 has_data = read_sha1_file(sha1, &has_type, &has_size);
356                 if (!has_data)
357                         die("cannot read existing object %s", sha1_to_hex(sha1));
358                 if (size != has_size || type != has_type ||
359                     memcmp(data, has_data, size) != 0)
360                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
361         }
362 }
363
364 static void resolve_delta(struct object_entry *delta_obj, void *base_data,
365                           unsigned long base_size, enum object_type type)
366 {
367         void *delta_data;
368         unsigned long delta_size;
369         void *result;
370         unsigned long result_size;
371         union delta_base delta_base;
372         int j, first, last;
373
374         delta_obj->real_type = type;
375         delta_data = get_data_from_pack(delta_obj);
376         delta_size = delta_obj->size;
377         result = patch_delta(base_data, base_size, delta_data, delta_size,
378                              &result_size);
379         free(delta_data);
380         if (!result)
381                 bad_object(delta_obj->offset, "failed to apply delta");
382         sha1_object(result, result_size, type, delta_obj->sha1);
383         nr_resolved_deltas++;
384
385         hashcpy(delta_base.sha1, delta_obj->sha1);
386         if (!find_delta_children(&delta_base, &first, &last)) {
387                 for (j = first; j <= last; j++) {
388                         struct object_entry *child = objects + deltas[j].obj_no;
389                         if (child->real_type == OBJ_REF_DELTA)
390                                 resolve_delta(child, result, result_size, type);
391                 }
392         }
393
394         memset(&delta_base, 0, sizeof(delta_base));
395         delta_base.offset = delta_obj->offset;
396         if (!find_delta_children(&delta_base, &first, &last)) {
397                 for (j = first; j <= last; j++) {
398                         struct object_entry *child = objects + deltas[j].obj_no;
399                         if (child->real_type == OBJ_OFS_DELTA)
400                                 resolve_delta(child, result, result_size, type);
401                 }
402         }
403
404         free(result);
405 }
406
407 static int compare_delta_entry(const void *a, const void *b)
408 {
409         const struct delta_entry *delta_a = a;
410         const struct delta_entry *delta_b = b;
411         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
412 }
413
414 /* Parse all objects and return the pack content SHA1 hash */
415 static void parse_pack_objects(unsigned char *sha1)
416 {
417         int i, percent = -1;
418         struct delta_entry *delta = deltas;
419         void *data;
420         struct stat st;
421
422         /*
423          * First pass:
424          * - find locations of all objects;
425          * - calculate SHA1 of all non-delta objects;
426          * - remember base (SHA1 or offset) for all deltas.
427          */
428         if (verbose)
429                 fprintf(stderr, "Indexing %d objects.\n", nr_objects);
430         for (i = 0; i < nr_objects; i++) {
431                 struct object_entry *obj = &objects[i];
432                 data = unpack_raw_entry(obj, &delta->base);
433                 obj->real_type = obj->type;
434                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
435                         nr_deltas++;
436                         delta->obj_no = i;
437                         delta++;
438                 } else
439                         sha1_object(data, obj->size, obj->type, obj->sha1);
440                 free(data);
441                 if (verbose)
442                         percent = display_progress(i+1, nr_objects, percent);
443         }
444         objects[i].offset = consumed_bytes;
445         if (verbose)
446                 fputc('\n', stderr);
447
448         /* Check pack integrity */
449         flush();
450         SHA1_Final(sha1, &input_ctx);
451         if (hashcmp(fill(20), sha1))
452                 die("pack is corrupted (SHA1 mismatch)");
453         use(20);
454
455         /* If input_fd is a file, we should have reached its end now. */
456         if (fstat(input_fd, &st))
457                 die("cannot fstat packfile: %s", strerror(errno));
458         if (S_ISREG(st.st_mode) &&
459                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
460                 die("pack has junk at the end");
461
462         if (!nr_deltas)
463                 return;
464
465         /* Sort deltas by base SHA1/offset for fast searching */
466         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
467               compare_delta_entry);
468
469         /*
470          * Second pass:
471          * - for all non-delta objects, look if it is used as a base for
472          *   deltas;
473          * - if used as a base, uncompress the object and apply all deltas,
474          *   recursively checking if the resulting object is used as a base
475          *   for some more deltas.
476          */
477         if (verbose)
478                 fprintf(stderr, "Resolving %d deltas.\n", nr_deltas);
479         for (i = 0; i < nr_objects; i++) {
480                 struct object_entry *obj = &objects[i];
481                 union delta_base base;
482                 int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
483
484                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
485                         continue;
486                 hashcpy(base.sha1, obj->sha1);
487                 ref = !find_delta_children(&base, &ref_first, &ref_last);
488                 memset(&base, 0, sizeof(base));
489                 base.offset = obj->offset;
490                 ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
491                 if (!ref && !ofs)
492                         continue;
493                 data = get_data_from_pack(obj);
494                 if (ref)
495                         for (j = ref_first; j <= ref_last; j++) {
496                                 struct object_entry *child = objects + deltas[j].obj_no;
497                                 if (child->real_type == OBJ_REF_DELTA)
498                                         resolve_delta(child, data,
499                                                       obj->size, obj->type);
500                         }
501                 if (ofs)
502                         for (j = ofs_first; j <= ofs_last; j++) {
503                                 struct object_entry *child = objects + deltas[j].obj_no;
504                                 if (child->real_type == OBJ_OFS_DELTA)
505                                         resolve_delta(child, data,
506                                                       obj->size, obj->type);
507                         }
508                 free(data);
509                 if (verbose)
510                         percent = display_progress(nr_resolved_deltas,
511                                                    nr_deltas, percent);
512         }
513         if (verbose && nr_resolved_deltas == nr_deltas)
514                 fputc('\n', stderr);
515 }
516
517 static int write_compressed(int fd, void *in, unsigned int size)
518 {
519         z_stream stream;
520         unsigned long maxsize;
521         void *out;
522
523         memset(&stream, 0, sizeof(stream));
524         deflateInit(&stream, zlib_compression_level);
525         maxsize = deflateBound(&stream, size);
526         out = xmalloc(maxsize);
527
528         /* Compress it */
529         stream.next_in = in;
530         stream.avail_in = size;
531         stream.next_out = out;
532         stream.avail_out = maxsize;
533         while (deflate(&stream, Z_FINISH) == Z_OK);
534         deflateEnd(&stream);
535
536         size = stream.total_out;
537         write_or_die(fd, out, size);
538         free(out);
539         return size;
540 }
541
542 static void append_obj_to_pack(const unsigned char *sha1, void *buf,
543                                unsigned long size, enum object_type type)
544 {
545         struct object_entry *obj = &objects[nr_objects++];
546         unsigned char header[10];
547         unsigned long s = size;
548         int n = 0;
549         unsigned char c = (type << 4) | (s & 15);
550         s >>= 4;
551         while (s) {
552                 header[n++] = c | 0x80;
553                 c = s & 0x7f;
554                 s >>= 7;
555         }
556         header[n++] = c;
557         write_or_die(output_fd, header, n);
558         obj[1].offset = obj[0].offset + n;
559         obj[1].offset += write_compressed(output_fd, buf, size);
560         hashcpy(obj->sha1, sha1);
561 }
562
563 static int delta_pos_compare(const void *_a, const void *_b)
564 {
565         struct delta_entry *a = *(struct delta_entry **)_a;
566         struct delta_entry *b = *(struct delta_entry **)_b;
567         return a->obj_no - b->obj_no;
568 }
569
570 static void fix_unresolved_deltas(int nr_unresolved)
571 {
572         struct delta_entry **sorted_by_pos;
573         int i, n = 0, percent = -1;
574
575         /*
576          * Since many unresolved deltas may well be themselves base objects
577          * for more unresolved deltas, we really want to include the
578          * smallest number of base objects that would cover as much delta
579          * as possible by picking the
580          * trunc deltas first, allowing for other deltas to resolve without
581          * additional base objects.  Since most base objects are to be found
582          * before deltas depending on them, a good heuristic is to start
583          * resolving deltas in the same order as their position in the pack.
584          */
585         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
586         for (i = 0; i < nr_deltas; i++) {
587                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
588                         continue;
589                 sorted_by_pos[n++] = &deltas[i];
590         }
591         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
592
593         for (i = 0; i < n; i++) {
594                 struct delta_entry *d = sorted_by_pos[i];
595                 void *data;
596                 unsigned long size;
597                 enum object_type type;
598                 int j, first, last;
599
600                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
601                         continue;
602                 data = read_sha1_file(d->base.sha1, &type, &size);
603                 if (!data)
604                         continue;
605
606                 find_delta_children(&d->base, &first, &last);
607                 for (j = first; j <= last; j++) {
608                         struct object_entry *child = objects + deltas[j].obj_no;
609                         if (child->real_type == OBJ_REF_DELTA)
610                                 resolve_delta(child, data, size, type);
611                 }
612
613                 if (check_sha1_signature(d->base.sha1, data, size, typename(type)))
614                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
615                 append_obj_to_pack(d->base.sha1, data, size, type);
616                 free(data);
617                 if (verbose)
618                         percent = display_progress(nr_resolved_deltas,
619                                                    nr_deltas, percent);
620         }
621         free(sorted_by_pos);
622         if (verbose)
623                 fputc('\n', stderr);
624 }
625
626 static void readjust_pack_header_and_sha1(unsigned char *sha1)
627 {
628         struct pack_header hdr;
629         SHA_CTX ctx;
630         int size;
631
632         /* Rewrite pack header with updated object number */
633         if (lseek(output_fd, 0, SEEK_SET) != 0)
634                 die("cannot seek back: %s", strerror(errno));
635         if (read_in_full(output_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
636                 die("cannot read pack header back: %s", strerror(errno));
637         hdr.hdr_entries = htonl(nr_objects);
638         if (lseek(output_fd, 0, SEEK_SET) != 0)
639                 die("cannot seek back: %s", strerror(errno));
640         write_or_die(output_fd, &hdr, sizeof(hdr));
641         if (lseek(output_fd, 0, SEEK_SET) != 0)
642                 die("cannot seek back: %s", strerror(errno));
643
644         /* Recompute and store the new pack's SHA1 */
645         SHA1_Init(&ctx);
646         do {
647                 unsigned char *buf[4096];
648                 size = xread(output_fd, buf, sizeof(buf));
649                 if (size < 0)
650                         die("cannot read pack data back: %s", strerror(errno));
651                 SHA1_Update(&ctx, buf, size);
652         } while (size > 0);
653         SHA1_Final(sha1, &ctx);
654         write_or_die(output_fd, sha1, 20);
655 }
656
657 static int sha1_compare(const void *_a, const void *_b)
658 {
659         struct object_entry *a = *(struct object_entry **)_a;
660         struct object_entry *b = *(struct object_entry **)_b;
661         return hashcmp(a->sha1, b->sha1);
662 }
663
664 /*
665  * On entry *sha1 contains the pack content SHA1 hash, on exit it is
666  * the SHA1 hash of sorted object names.
667  */
668 static const char *write_index_file(const char *index_name, unsigned char *sha1)
669 {
670         struct sha1file *f;
671         struct object_entry **sorted_by_sha, **list, **last;
672         unsigned int array[256];
673         int i, fd;
674         SHA_CTX ctx;
675
676         if (nr_objects) {
677                 sorted_by_sha =
678                         xcalloc(nr_objects, sizeof(struct object_entry *));
679                 list = sorted_by_sha;
680                 last = sorted_by_sha + nr_objects;
681                 for (i = 0; i < nr_objects; ++i)
682                         sorted_by_sha[i] = &objects[i];
683                 qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
684                       sha1_compare);
685
686         }
687         else
688                 sorted_by_sha = list = last = NULL;
689
690         if (!index_name) {
691                 static char tmpfile[PATH_MAX];
692                 snprintf(tmpfile, sizeof(tmpfile),
693                          "%s/tmp_idx_XXXXXX", get_object_directory());
694                 fd = mkstemp(tmpfile);
695                 index_name = xstrdup(tmpfile);
696         } else {
697                 unlink(index_name);
698                 fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
699         }
700         if (fd < 0)
701                 die("unable to create %s: %s", index_name, strerror(errno));
702         f = sha1fd(fd, index_name);
703
704         /*
705          * Write the first-level table (the list is sorted,
706          * but we use a 256-entry lookup to be able to avoid
707          * having to do eight extra binary search iterations).
708          */
709         for (i = 0; i < 256; i++) {
710                 struct object_entry **next = list;
711                 while (next < last) {
712                         struct object_entry *obj = *next;
713                         if (obj->sha1[0] != i)
714                                 break;
715                         next++;
716                 }
717                 array[i] = htonl(next - sorted_by_sha);
718                 list = next;
719         }
720         sha1write(f, array, 256 * sizeof(int));
721
722         /* recompute the SHA1 hash of sorted object names.
723          * currently pack-objects does not do this, but that
724          * can be fixed.
725          */
726         SHA1_Init(&ctx);
727         /*
728          * Write the actual SHA1 entries..
729          */
730         list = sorted_by_sha;
731         for (i = 0; i < nr_objects; i++) {
732                 struct object_entry *obj = *list++;
733                 unsigned int offset = htonl(obj->offset);
734                 sha1write(f, &offset, 4);
735                 sha1write(f, obj->sha1, 20);
736                 SHA1_Update(&ctx, obj->sha1, 20);
737         }
738         sha1write(f, sha1, 20);
739         sha1close(f, NULL, 1);
740         free(sorted_by_sha);
741         SHA1_Final(sha1, &ctx);
742         return index_name;
743 }
744
745 static void final(const char *final_pack_name, const char *curr_pack_name,
746                   const char *final_index_name, const char *curr_index_name,
747                   const char *keep_name, const char *keep_msg,
748                   unsigned char *sha1)
749 {
750         const char *report = "pack";
751         char name[PATH_MAX];
752         int err;
753
754         if (!from_stdin) {
755                 close(input_fd);
756         } else {
757                 err = close(output_fd);
758                 if (err)
759                         die("error while closing pack file: %s", strerror(errno));
760                 chmod(curr_pack_name, 0444);
761         }
762
763         if (keep_msg) {
764                 int keep_fd, keep_msg_len = strlen(keep_msg);
765                 if (!keep_name) {
766                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
767                                  get_object_directory(), sha1_to_hex(sha1));
768                         keep_name = name;
769                 }
770                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
771                 if (keep_fd < 0) {
772                         if (errno != EEXIST)
773                                 die("cannot write keep file");
774                 } else {
775                         if (keep_msg_len > 0) {
776                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
777                                 write_or_die(keep_fd, "\n", 1);
778                         }
779                         close(keep_fd);
780                         report = "keep";
781                 }
782         }
783
784         if (final_pack_name != curr_pack_name) {
785                 if (!final_pack_name) {
786                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
787                                  get_object_directory(), sha1_to_hex(sha1));
788                         final_pack_name = name;
789                 }
790                 if (move_temp_to_file(curr_pack_name, final_pack_name))
791                         die("cannot store pack file");
792         }
793
794         chmod(curr_index_name, 0444);
795         if (final_index_name != curr_index_name) {
796                 if (!final_index_name) {
797                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
798                                  get_object_directory(), sha1_to_hex(sha1));
799                         final_index_name = name;
800                 }
801                 if (move_temp_to_file(curr_index_name, final_index_name))
802                         die("cannot store index file");
803         }
804
805         if (!from_stdin) {
806                 printf("%s\n", sha1_to_hex(sha1));
807         } else {
808                 char buf[48];
809                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
810                                    report, sha1_to_hex(sha1));
811                 write_or_die(1, buf, len);
812
813                 /*
814                  * Let's just mimic git-unpack-objects here and write
815                  * the last part of the input buffer to stdout.
816                  */
817                 while (input_len) {
818                         err = xwrite(1, input_buffer + input_offset, input_len);
819                         if (err <= 0)
820                                 break;
821                         input_len -= err;
822                         input_offset += err;
823                 }
824         }
825 }
826
827 int main(int argc, char **argv)
828 {
829         int i, fix_thin_pack = 0;
830         const char *curr_pack, *pack_name = NULL;
831         const char *curr_index, *index_name = NULL;
832         const char *keep_name = NULL, *keep_msg = NULL;
833         char *index_name_buf = NULL, *keep_name_buf = NULL;
834         unsigned char sha1[20];
835
836         for (i = 1; i < argc; i++) {
837                 const char *arg = argv[i];
838
839                 if (*arg == '-') {
840                         if (!strcmp(arg, "--stdin")) {
841                                 from_stdin = 1;
842                         } else if (!strcmp(arg, "--fix-thin")) {
843                                 fix_thin_pack = 1;
844                         } else if (!strcmp(arg, "--keep")) {
845                                 keep_msg = "";
846                         } else if (!prefixcmp(arg, "--keep=")) {
847                                 keep_msg = arg + 7;
848                         } else if (!prefixcmp(arg, "--pack_header=")) {
849                                 struct pack_header *hdr;
850                                 char *c;
851
852                                 hdr = (struct pack_header *)input_buffer;
853                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
854                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
855                                 if (*c != ',')
856                                         die("bad %s", arg);
857                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
858                                 if (*c)
859                                         die("bad %s", arg);
860                                 input_len = sizeof(*hdr);
861                         } else if (!strcmp(arg, "-v")) {
862                                 verbose = 1;
863                         } else if (!strcmp(arg, "-o")) {
864                                 if (index_name || (i+1) >= argc)
865                                         usage(index_pack_usage);
866                                 index_name = argv[++i];
867                         } else
868                                 usage(index_pack_usage);
869                         continue;
870                 }
871
872                 if (pack_name)
873                         usage(index_pack_usage);
874                 pack_name = arg;
875         }
876
877         if (!pack_name && !from_stdin)
878                 usage(index_pack_usage);
879         if (fix_thin_pack && !from_stdin)
880                 die("--fix-thin cannot be used without --stdin");
881         if (!index_name && pack_name) {
882                 int len = strlen(pack_name);
883                 if (!has_extension(pack_name, ".pack"))
884                         die("packfile name '%s' does not end with '.pack'",
885                             pack_name);
886                 index_name_buf = xmalloc(len);
887                 memcpy(index_name_buf, pack_name, len - 5);
888                 strcpy(index_name_buf + len - 5, ".idx");
889                 index_name = index_name_buf;
890         }
891         if (keep_msg && !keep_name && pack_name) {
892                 int len = strlen(pack_name);
893                 if (!has_extension(pack_name, ".pack"))
894                         die("packfile name '%s' does not end with '.pack'",
895                             pack_name);
896                 keep_name_buf = xmalloc(len);
897                 memcpy(keep_name_buf, pack_name, len - 5);
898                 strcpy(keep_name_buf + len - 5, ".keep");
899                 keep_name = keep_name_buf;
900         }
901
902         curr_pack = open_pack_file(pack_name);
903         parse_pack_header();
904         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
905         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
906         if (verbose)
907                 setup_progress_signal();
908         parse_pack_objects(sha1);
909         if (nr_deltas != nr_resolved_deltas) {
910                 if (fix_thin_pack) {
911                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
912                         int nr_objects_initial = nr_objects;
913                         if (nr_unresolved <= 0)
914                                 die("confusion beyond insanity");
915                         objects = xrealloc(objects,
916                                            (nr_objects + nr_unresolved + 1)
917                                            * sizeof(*objects));
918                         fix_unresolved_deltas(nr_unresolved);
919                         if (verbose)
920                                 fprintf(stderr, "%d objects were added to complete this thin pack.\n",
921                                         nr_objects - nr_objects_initial);
922                         readjust_pack_header_and_sha1(sha1);
923                 }
924                 if (nr_deltas != nr_resolved_deltas)
925                         die("pack has %d unresolved deltas",
926                             nr_deltas - nr_resolved_deltas);
927         } else {
928                 /* Flush remaining pack final 20-byte SHA1. */
929                 flush();
930         }
931         free(deltas);
932         curr_index = write_index_file(index_name, sha1);
933         final(pack_name, curr_pack,
934                 index_name, curr_index,
935                 keep_name, keep_msg,
936                 sha1);
937         free(objects);
938         free(index_name_buf);
939         free(keep_name_buf);
940
941         return 0;
942 }