Clarify fetch error for missing objects.
[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 #include <sys/time.h>
10 #include <signal.h>
11
12 static const char index_pack_usage[] =
13 "git-index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
14
15 struct object_entry
16 {
17         unsigned long offset;
18         unsigned long size;
19         unsigned int hdr_size;
20         enum object_type type;
21         enum object_type real_type;
22         unsigned char sha1[20];
23 };
24
25 union delta_base {
26         unsigned char sha1[20];
27         unsigned long offset;
28 };
29
30 /*
31  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
32  * to memcmp() only the first 20 bytes.
33  */
34 #define UNION_BASE_SZ   20
35
36 struct delta_entry
37 {
38         union delta_base base;
39         int obj_no;
40 };
41
42 static struct object_entry *objects;
43 static struct delta_entry *deltas;
44 static int nr_objects;
45 static int nr_deltas;
46 static int nr_resolved_deltas;
47
48 static int from_stdin;
49 static int verbose;
50
51 static volatile sig_atomic_t progress_update;
52
53 static void progress_interval(int signum)
54 {
55         progress_update = 1;
56 }
57
58 static void setup_progress_signal(void)
59 {
60         struct sigaction sa;
61         struct itimerval v;
62
63         memset(&sa, 0, sizeof(sa));
64         sa.sa_handler = progress_interval;
65         sigemptyset(&sa.sa_mask);
66         sa.sa_flags = SA_RESTART;
67         sigaction(SIGALRM, &sa, NULL);
68
69         v.it_interval.tv_sec = 1;
70         v.it_interval.tv_usec = 0;
71         v.it_value = v.it_interval;
72         setitimer(ITIMER_REAL, &v, NULL);
73
74 }
75
76 static unsigned display_progress(unsigned n, unsigned total, unsigned last_pc)
77 {
78         unsigned percent = n * 100 / total;
79         if (percent != last_pc || progress_update) {
80                 fprintf(stderr, "%4u%% (%u/%u) done\r", percent, n, total);
81                 progress_update = 0;
82         }
83         return percent;
84 }
85
86 /* We always read in 4kB chunks. */
87 static unsigned char input_buffer[4096];
88 static unsigned long input_offset, input_len, consumed_bytes;
89 static SHA_CTX input_ctx;
90 static int input_fd, output_fd, mmap_fd;
91
92 /* Discard current buffer used content. */
93 static void flush(void)
94 {
95         if (input_offset) {
96                 if (output_fd >= 0)
97                         write_or_die(output_fd, input_buffer, input_offset);
98                 SHA1_Update(&input_ctx, input_buffer, input_offset);
99                 memmove(input_buffer, input_buffer + input_offset, input_len);
100                 input_offset = 0;
101         }
102 }
103
104 /*
105  * Make sure at least "min" bytes are available in the buffer, and
106  * return the pointer to the buffer.
107  */
108 static void *fill(int min)
109 {
110         if (min <= input_len)
111                 return input_buffer + input_offset;
112         if (min > sizeof(input_buffer))
113                 die("cannot fill %d bytes", min);
114         flush();
115         do {
116                 int ret = xread(input_fd, input_buffer + input_len,
117                                 sizeof(input_buffer) - input_len);
118                 if (ret <= 0) {
119                         if (!ret)
120                                 die("early EOF");
121                         die("read error on input: %s", strerror(errno));
122                 }
123                 input_len += ret;
124         } while (input_len < min);
125         return input_buffer;
126 }
127
128 static void use(int bytes)
129 {
130         if (bytes > input_len)
131                 die("used more bytes than were available");
132         input_len -= bytes;
133         input_offset += bytes;
134         consumed_bytes += bytes;
135 }
136
137 static const char *open_pack_file(const char *pack_name)
138 {
139         if (from_stdin) {
140                 input_fd = 0;
141                 if (!pack_name) {
142                         static char tmpfile[PATH_MAX];
143                         snprintf(tmpfile, sizeof(tmpfile),
144                                  "%s/pack_XXXXXX", get_object_directory());
145                         output_fd = mkstemp(tmpfile);
146                         pack_name = xstrdup(tmpfile);
147                 } else
148                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
149                 if (output_fd < 0)
150                         die("unable to create %s: %s\n", pack_name, strerror(errno));
151                 mmap_fd = output_fd;
152         } else {
153                 input_fd = open(pack_name, O_RDONLY);
154                 if (input_fd < 0)
155                         die("cannot open packfile '%s': %s",
156                             pack_name, strerror(errno));
157                 output_fd = -1;
158                 mmap_fd = input_fd;
159         }
160         SHA1_Init(&input_ctx);
161         return pack_name;
162 }
163
164 static void parse_pack_header(void)
165 {
166         struct pack_header *hdr = fill(sizeof(struct pack_header));
167
168         /* Header consistency check */
169         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
170                 die("pack signature mismatch");
171         if (!pack_version_ok(hdr->hdr_version))
172                 die("pack version %d unsupported", ntohl(hdr->hdr_version));
173
174         nr_objects = ntohl(hdr->hdr_entries);
175         use(sizeof(struct pack_header));
176 }
177
178 static void bad_object(unsigned long offset, const char *format,
179                        ...) NORETURN __attribute__((format (printf, 2, 3)));
180
181 static void bad_object(unsigned long offset, const char *format, ...)
182 {
183         va_list params;
184         char buf[1024];
185
186         va_start(params, format);
187         vsnprintf(buf, sizeof(buf), format, params);
188         va_end(params);
189         die("pack has bad object at offset %lu: %s", offset, buf);
190 }
191
192 static void *unpack_entry_data(unsigned long offset, unsigned long size)
193 {
194         z_stream stream;
195         void *buf = xmalloc(size);
196
197         memset(&stream, 0, sizeof(stream));
198         stream.next_out = buf;
199         stream.avail_out = size;
200         stream.next_in = fill(1);
201         stream.avail_in = input_len;
202         inflateInit(&stream);
203
204         for (;;) {
205                 int ret = inflate(&stream, 0);
206                 use(input_len - stream.avail_in);
207                 if (stream.total_out == size && ret == Z_STREAM_END)
208                         break;
209                 if (ret != Z_OK)
210                         bad_object(offset, "inflate returned %d", ret);
211                 stream.next_in = fill(1);
212                 stream.avail_in = input_len;
213         }
214         inflateEnd(&stream);
215         return buf;
216 }
217
218 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
219 {
220         unsigned char *p, c;
221         unsigned long size, base_offset;
222         unsigned shift;
223
224         obj->offset = consumed_bytes;
225
226         p = fill(1);
227         c = *p;
228         use(1);
229         obj->type = (c >> 4) & 7;
230         size = (c & 15);
231         shift = 4;
232         while (c & 0x80) {
233                 p = fill(1);
234                 c = *p;
235                 use(1);
236                 size += (c & 0x7fUL) << shift;
237                 shift += 7;
238         }
239         obj->size = size;
240
241         switch (obj->type) {
242         case OBJ_REF_DELTA:
243                 hashcpy(delta_base->sha1, fill(20));
244                 use(20);
245                 break;
246         case OBJ_OFS_DELTA:
247                 memset(delta_base, 0, sizeof(*delta_base));
248                 p = fill(1);
249                 c = *p;
250                 use(1);
251                 base_offset = c & 127;
252                 while (c & 128) {
253                         base_offset += 1;
254                         if (!base_offset || base_offset & ~(~0UL >> 7))
255                                 bad_object(obj->offset, "offset value overflow for delta base object");
256                         p = fill(1);
257                         c = *p;
258                         use(1);
259                         base_offset = (base_offset << 7) + (c & 127);
260                 }
261                 delta_base->offset = obj->offset - base_offset;
262                 if (delta_base->offset >= obj->offset)
263                         bad_object(obj->offset, "delta base offset is out of bound");
264                 break;
265         case OBJ_COMMIT:
266         case OBJ_TREE:
267         case OBJ_BLOB:
268         case OBJ_TAG:
269                 break;
270         default:
271                 bad_object(obj->offset, "bad object type %d", obj->type);
272         }
273         obj->hdr_size = consumed_bytes - obj->offset;
274
275         return unpack_entry_data(obj->offset, obj->size);
276 }
277
278 static void *get_data_from_pack(struct object_entry *obj)
279 {
280         unsigned long from = obj[0].offset + obj[0].hdr_size;
281         unsigned long len = obj[1].offset - from;
282         unsigned pg_offset = from % getpagesize();
283         unsigned char *map, *data;
284         z_stream stream;
285         int st;
286
287         map = mmap(NULL, len + pg_offset, PROT_READ, MAP_PRIVATE,
288                    mmap_fd, from - pg_offset);
289         if (map == MAP_FAILED)
290                 die("cannot mmap pack file: %s", strerror(errno));
291         data = xmalloc(obj->size);
292         memset(&stream, 0, sizeof(stream));
293         stream.next_out = data;
294         stream.avail_out = obj->size;
295         stream.next_in = map + pg_offset;
296         stream.avail_in = len;
297         inflateInit(&stream);
298         while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
299         inflateEnd(&stream);
300         if (st != Z_STREAM_END || stream.total_out != obj->size)
301                 die("serious inflate inconsistency");
302         munmap(map, len + pg_offset);
303         return data;
304 }
305
306 static int find_delta(const union delta_base *base)
307 {
308         int first = 0, last = nr_deltas;
309
310         while (first < last) {
311                 int next = (first + last) / 2;
312                 struct delta_entry *delta = &deltas[next];
313                 int cmp;
314
315                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
316                 if (!cmp)
317                         return next;
318                 if (cmp < 0) {
319                         last = next;
320                         continue;
321                 }
322                 first = next+1;
323         }
324         return -first-1;
325 }
326
327 static int find_delta_children(const union delta_base *base,
328                                int *first_index, int *last_index)
329 {
330         int first = find_delta(base);
331         int last = first;
332         int end = nr_deltas - 1;
333
334         if (first < 0)
335                 return -1;
336         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
337                 --first;
338         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
339                 ++last;
340         *first_index = first;
341         *last_index = last;
342         return 0;
343 }
344
345 static void sha1_object(const void *data, unsigned long size,
346                         enum object_type type, unsigned char *sha1)
347 {
348         SHA_CTX ctx;
349         char header[50];
350         int header_size;
351         const char *type_str;
352
353         switch (type) {
354         case OBJ_COMMIT: type_str = commit_type; break;
355         case OBJ_TREE:   type_str = tree_type; break;
356         case OBJ_BLOB:   type_str = blob_type; break;
357         case OBJ_TAG:    type_str = tag_type; break;
358         default:
359                 die("bad type %d", type);
360         }
361
362         header_size = sprintf(header, "%s %lu", type_str, size) + 1;
363
364         SHA1_Init(&ctx);
365         SHA1_Update(&ctx, header, header_size);
366         SHA1_Update(&ctx, data, size);
367         SHA1_Final(sha1, &ctx);
368 }
369
370 static void resolve_delta(struct object_entry *delta_obj, void *base_data,
371                           unsigned long base_size, enum object_type type)
372 {
373         void *delta_data;
374         unsigned long delta_size;
375         void *result;
376         unsigned long result_size;
377         union delta_base delta_base;
378         int j, first, last;
379
380         delta_obj->real_type = type;
381         delta_data = get_data_from_pack(delta_obj);
382         delta_size = delta_obj->size;
383         result = patch_delta(base_data, base_size, delta_data, delta_size,
384                              &result_size);
385         free(delta_data);
386         if (!result)
387                 bad_object(delta_obj->offset, "failed to apply delta");
388         sha1_object(result, result_size, type, delta_obj->sha1);
389         nr_resolved_deltas++;
390
391         hashcpy(delta_base.sha1, delta_obj->sha1);
392         if (!find_delta_children(&delta_base, &first, &last)) {
393                 for (j = first; j <= last; j++) {
394                         struct object_entry *child = objects + deltas[j].obj_no;
395                         if (child->real_type == OBJ_REF_DELTA)
396                                 resolve_delta(child, result, result_size, type);
397                 }
398         }
399
400         memset(&delta_base, 0, sizeof(delta_base));
401         delta_base.offset = delta_obj->offset;
402         if (!find_delta_children(&delta_base, &first, &last)) {
403                 for (j = first; j <= last; j++) {
404                         struct object_entry *child = objects + deltas[j].obj_no;
405                         if (child->real_type == OBJ_OFS_DELTA)
406                                 resolve_delta(child, result, result_size, type);
407                 }
408         }
409
410         free(result);
411 }
412
413 static int compare_delta_entry(const void *a, const void *b)
414 {
415         const struct delta_entry *delta_a = a;
416         const struct delta_entry *delta_b = b;
417         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
418 }
419
420 /* Parse all objects and return the pack content SHA1 hash */
421 static void parse_pack_objects(unsigned char *sha1)
422 {
423         int i, percent = -1;
424         struct delta_entry *delta = deltas;
425         void *data;
426         struct stat st;
427
428         /*
429          * First pass:
430          * - find locations of all objects;
431          * - calculate SHA1 of all non-delta objects;
432          * - remember base (SHA1 or offset) for all deltas.
433          */
434         if (verbose)
435                 fprintf(stderr, "Indexing %d objects.\n", nr_objects);
436         for (i = 0; i < nr_objects; i++) {
437                 struct object_entry *obj = &objects[i];
438                 data = unpack_raw_entry(obj, &delta->base);
439                 obj->real_type = obj->type;
440                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
441                         nr_deltas++;
442                         delta->obj_no = i;
443                         delta++;
444                 } else
445                         sha1_object(data, obj->size, obj->type, obj->sha1);
446                 free(data);
447                 if (verbose)
448                         percent = display_progress(i+1, nr_objects, percent);
449         }
450         objects[i].offset = consumed_bytes;
451         if (verbose)
452                 fputc('\n', stderr);
453
454         /* Check pack integrity */
455         flush();
456         SHA1_Final(sha1, &input_ctx);
457         if (hashcmp(fill(20), sha1))
458                 die("pack is corrupted (SHA1 mismatch)");
459         use(20);
460
461         /* If input_fd is a file, we should have reached its end now. */
462         if (fstat(input_fd, &st))
463                 die("cannot fstat packfile: %s", strerror(errno));
464         if (S_ISREG(st.st_mode) && st.st_size != consumed_bytes)
465                 die("pack has junk at the end");
466
467         if (!nr_deltas)
468                 return;
469
470         /* Sort deltas by base SHA1/offset for fast searching */
471         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
472               compare_delta_entry);
473
474         /*
475          * Second pass:
476          * - for all non-delta objects, look if it is used as a base for
477          *   deltas;
478          * - if used as a base, uncompress the object and apply all deltas,
479          *   recursively checking if the resulting object is used as a base
480          *   for some more deltas.
481          */
482         if (verbose)
483                 fprintf(stderr, "Resolving %d deltas.\n", nr_deltas);
484         for (i = 0; i < nr_objects; i++) {
485                 struct object_entry *obj = &objects[i];
486                 union delta_base base;
487                 int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
488
489                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
490                         continue;
491                 hashcpy(base.sha1, obj->sha1);
492                 ref = !find_delta_children(&base, &ref_first, &ref_last);
493                 memset(&base, 0, sizeof(base));
494                 base.offset = obj->offset;
495                 ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
496                 if (!ref && !ofs)
497                         continue;
498                 data = get_data_from_pack(obj);
499                 if (ref)
500                         for (j = ref_first; j <= ref_last; j++) {
501                                 struct object_entry *child = objects + deltas[j].obj_no;
502                                 if (child->real_type == OBJ_REF_DELTA)
503                                         resolve_delta(child, data,
504                                                       obj->size, obj->type);
505                         }
506                 if (ofs)
507                         for (j = ofs_first; j <= ofs_last; j++) {
508                                 struct object_entry *child = objects + deltas[j].obj_no;
509                                 if (child->real_type == OBJ_OFS_DELTA)
510                                         resolve_delta(child, data,
511                                                       obj->size, obj->type);
512                         }
513                 free(data);
514                 if (verbose)
515                         percent = display_progress(nr_resolved_deltas,
516                                                    nr_deltas, percent);
517         }
518         if (verbose && nr_resolved_deltas == nr_deltas)
519                 fputc('\n', stderr);
520 }
521
522 static int write_compressed(int fd, void *in, unsigned int size)
523 {
524         z_stream stream;
525         unsigned long maxsize;
526         void *out;
527
528         memset(&stream, 0, sizeof(stream));
529         deflateInit(&stream, zlib_compression_level);
530         maxsize = deflateBound(&stream, size);
531         out = xmalloc(maxsize);
532
533         /* Compress it */
534         stream.next_in = in;
535         stream.avail_in = size;
536         stream.next_out = out;
537         stream.avail_out = maxsize;
538         while (deflate(&stream, Z_FINISH) == Z_OK);
539         deflateEnd(&stream);
540
541         size = stream.total_out;
542         write_or_die(fd, out, size);
543         free(out);
544         return size;
545 }
546
547 static void append_obj_to_pack(void *buf,
548                                unsigned long size, enum object_type type)
549 {
550         struct object_entry *obj = &objects[nr_objects++];
551         unsigned char header[10];
552         unsigned long s = size;
553         int n = 0;
554         unsigned char c = (type << 4) | (s & 15);
555         s >>= 4;
556         while (s) {
557                 header[n++] = c | 0x80;
558                 c = s & 0x7f;
559                 s >>= 7;
560         }
561         header[n++] = c;
562         write_or_die(output_fd, header, n);
563         obj[1].offset = obj[0].offset + n;
564         obj[1].offset += write_compressed(output_fd, buf, size);
565         sha1_object(buf, size, type, obj->sha1);
566 }
567
568 static int delta_pos_compare(const void *_a, const void *_b)
569 {
570         struct delta_entry *a = *(struct delta_entry **)_a;
571         struct delta_entry *b = *(struct delta_entry **)_b;
572         return a->obj_no - b->obj_no;
573 }
574
575 static void fix_unresolved_deltas(int nr_unresolved)
576 {
577         struct delta_entry **sorted_by_pos;
578         int i, n = 0, percent = -1;
579
580         /*
581          * Since many unresolved deltas may well be themselves base objects
582          * for more unresolved deltas, we really want to include the
583          * smallest number of base objects that would cover as much delta
584          * as possible by picking the
585          * trunc deltas first, allowing for other deltas to resolve without
586          * additional base objects.  Since most base objects are to be found
587          * before deltas depending on them, a good heuristic is to start
588          * resolving deltas in the same order as their position in the pack.
589          */
590         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
591         for (i = 0; i < nr_deltas; i++) {
592                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
593                         continue;
594                 sorted_by_pos[n++] = &deltas[i];
595         }
596         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
597
598         for (i = 0; i < n; i++) {
599                 struct delta_entry *d = sorted_by_pos[i];
600                 void *data;
601                 unsigned long size;
602                 char type[10];
603                 enum object_type obj_type;
604                 int j, first, last;
605
606                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
607                         continue;
608                 data = read_sha1_file(d->base.sha1, type, &size);
609                 if (!data)
610                         continue;
611                 if      (!strcmp(type, blob_type))   obj_type = OBJ_BLOB;
612                 else if (!strcmp(type, tree_type))   obj_type = OBJ_TREE;
613                 else if (!strcmp(type, commit_type)) obj_type = OBJ_COMMIT;
614                 else if (!strcmp(type, tag_type))    obj_type = OBJ_TAG;
615                 else die("base object %s is of type '%s'",
616                          sha1_to_hex(d->base.sha1), type);
617
618                 find_delta_children(&d->base, &first, &last);
619                 for (j = first; j <= last; j++) {
620                         struct object_entry *child = objects + deltas[j].obj_no;
621                         if (child->real_type == OBJ_REF_DELTA)
622                                 resolve_delta(child, data, size, obj_type);
623                 }
624
625                 append_obj_to_pack(data, size, obj_type);
626                 free(data);
627                 if (verbose)
628                         percent = display_progress(nr_resolved_deltas,
629                                                    nr_deltas, percent);
630         }
631         free(sorted_by_pos);
632         if (verbose)
633                 fputc('\n', stderr);
634 }
635
636 static void readjust_pack_header_and_sha1(unsigned char *sha1)
637 {
638         struct pack_header hdr;
639         SHA_CTX ctx;
640         int size;
641
642         /* Rewrite pack header with updated object number */
643         if (lseek(output_fd, 0, SEEK_SET) != 0)
644                 die("cannot seek back: %s", strerror(errno));
645         if (xread(output_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
646                 die("cannot read pack header back: %s", strerror(errno));
647         hdr.hdr_entries = htonl(nr_objects);
648         if (lseek(output_fd, 0, SEEK_SET) != 0)
649                 die("cannot seek back: %s", strerror(errno));
650         write_or_die(output_fd, &hdr, sizeof(hdr));
651         if (lseek(output_fd, 0, SEEK_SET) != 0)
652                 die("cannot seek back: %s", strerror(errno));
653
654         /* Recompute and store the new pack's SHA1 */
655         SHA1_Init(&ctx);
656         do {
657                 unsigned char *buf[4096];
658                 size = xread(output_fd, buf, sizeof(buf));
659                 if (size < 0)
660                         die("cannot read pack data back: %s", strerror(errno));
661                 SHA1_Update(&ctx, buf, size);
662         } while (size > 0);
663         SHA1_Final(sha1, &ctx);
664         write_or_die(output_fd, sha1, 20);
665 }
666
667 static int sha1_compare(const void *_a, const void *_b)
668 {
669         struct object_entry *a = *(struct object_entry **)_a;
670         struct object_entry *b = *(struct object_entry **)_b;
671         return hashcmp(a->sha1, b->sha1);
672 }
673
674 /*
675  * On entry *sha1 contains the pack content SHA1 hash, on exit it is
676  * the SHA1 hash of sorted object names.
677  */
678 static const char *write_index_file(const char *index_name, unsigned char *sha1)
679 {
680         struct sha1file *f;
681         struct object_entry **sorted_by_sha, **list, **last;
682         unsigned int array[256];
683         int i, fd;
684         SHA_CTX ctx;
685
686         if (nr_objects) {
687                 sorted_by_sha =
688                         xcalloc(nr_objects, sizeof(struct object_entry *));
689                 list = sorted_by_sha;
690                 last = sorted_by_sha + nr_objects;
691                 for (i = 0; i < nr_objects; ++i)
692                         sorted_by_sha[i] = &objects[i];
693                 qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
694                       sha1_compare);
695
696         }
697         else
698                 sorted_by_sha = list = last = NULL;
699
700         if (!index_name) {
701                 static char tmpfile[PATH_MAX];
702                 snprintf(tmpfile, sizeof(tmpfile),
703                          "%s/index_XXXXXX", get_object_directory());
704                 fd = mkstemp(tmpfile);
705                 index_name = xstrdup(tmpfile);
706         } else {
707                 unlink(index_name);
708                 fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
709         }
710         if (fd < 0)
711                 die("unable to create %s: %s", index_name, strerror(errno));
712         f = sha1fd(fd, index_name);
713
714         /*
715          * Write the first-level table (the list is sorted,
716          * but we use a 256-entry lookup to be able to avoid
717          * having to do eight extra binary search iterations).
718          */
719         for (i = 0; i < 256; i++) {
720                 struct object_entry **next = list;
721                 while (next < last) {
722                         struct object_entry *obj = *next;
723                         if (obj->sha1[0] != i)
724                                 break;
725                         next++;
726                 }
727                 array[i] = htonl(next - sorted_by_sha);
728                 list = next;
729         }
730         sha1write(f, array, 256 * sizeof(int));
731
732         /* recompute the SHA1 hash of sorted object names.
733          * currently pack-objects does not do this, but that
734          * can be fixed.
735          */
736         SHA1_Init(&ctx);
737         /*
738          * Write the actual SHA1 entries..
739          */
740         list = sorted_by_sha;
741         for (i = 0; i < nr_objects; i++) {
742                 struct object_entry *obj = *list++;
743                 unsigned int offset = htonl(obj->offset);
744                 sha1write(f, &offset, 4);
745                 sha1write(f, obj->sha1, 20);
746                 SHA1_Update(&ctx, obj->sha1, 20);
747         }
748         sha1write(f, sha1, 20);
749         sha1close(f, NULL, 1);
750         free(sorted_by_sha);
751         SHA1_Final(sha1, &ctx);
752         return index_name;
753 }
754
755 static void final(const char *final_pack_name, const char *curr_pack_name,
756                   const char *final_index_name, const char *curr_index_name,
757                   const char *keep_name, const char *keep_msg,
758                   unsigned char *sha1)
759 {
760         char *report = "pack";
761         char name[PATH_MAX];
762         int err;
763
764         if (!from_stdin) {
765                 close(input_fd);
766         } else {
767                 err = close(output_fd);
768                 if (err)
769                         die("error while closing pack file: %s", strerror(errno));
770                 chmod(curr_pack_name, 0444);
771         }
772
773         if (keep_msg) {
774                 int keep_fd, keep_msg_len = strlen(keep_msg);
775                 if (!keep_name) {
776                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
777                                  get_object_directory(), sha1_to_hex(sha1));
778                         keep_name = name;
779                 }
780                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
781                 if (keep_fd < 0) {
782                         if (errno != EEXIST)
783                                 die("cannot write keep file");
784                 } else {
785                         if (keep_msg_len > 0) {
786                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
787                                 write_or_die(keep_fd, "\n", 1);
788                         }
789                         close(keep_fd);
790                         report = "keep";
791                 }
792         }
793
794         if (final_pack_name != curr_pack_name) {
795                 if (!final_pack_name) {
796                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
797                                  get_object_directory(), sha1_to_hex(sha1));
798                         final_pack_name = name;
799                 }
800                 if (move_temp_to_file(curr_pack_name, final_pack_name))
801                         die("cannot store pack file");
802         }
803
804         chmod(curr_index_name, 0444);
805         if (final_index_name != curr_index_name) {
806                 if (!final_index_name) {
807                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
808                                  get_object_directory(), sha1_to_hex(sha1));
809                         final_index_name = name;
810                 }
811                 if (move_temp_to_file(curr_index_name, final_index_name))
812                         die("cannot store index file");
813         }
814
815         if (!from_stdin) {
816                 printf("%s\n", sha1_to_hex(sha1));
817         } else {
818                 char buf[48];
819                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
820                                    report, sha1_to_hex(sha1));
821                 xwrite(1, buf, len);
822
823                 /*
824                  * Let's just mimic git-unpack-objects here and write
825                  * the last part of the input buffer to stdout.
826                  */
827                 while (input_len) {
828                         err = xwrite(1, input_buffer + input_offset, input_len);
829                         if (err <= 0)
830                                 break;
831                         input_len -= err;
832                         input_offset += err;
833                 }
834         }
835 }
836
837 int main(int argc, char **argv)
838 {
839         int i, fix_thin_pack = 0;
840         const char *curr_pack, *pack_name = NULL;
841         const char *curr_index, *index_name = NULL;
842         const char *keep_name = NULL, *keep_msg = NULL;
843         char *index_name_buf = NULL, *keep_name_buf = NULL;
844         unsigned char sha1[20];
845
846         for (i = 1; i < argc; i++) {
847                 const char *arg = argv[i];
848
849                 if (*arg == '-') {
850                         if (!strcmp(arg, "--stdin")) {
851                                 from_stdin = 1;
852                         } else if (!strcmp(arg, "--fix-thin")) {
853                                 fix_thin_pack = 1;
854                         } else if (!strcmp(arg, "--keep")) {
855                                 keep_msg = "";
856                         } else if (!strncmp(arg, "--keep=", 7)) {
857                                 keep_msg = arg + 7;
858                         } else if (!strncmp(arg, "--pack_header=", 14)) {
859                                 struct pack_header *hdr;
860                                 char *c;
861
862                                 hdr = (struct pack_header *)input_buffer;
863                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
864                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
865                                 if (*c != ',')
866                                         die("bad %s", arg);
867                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
868                                 if (*c)
869                                         die("bad %s", arg);
870                                 input_len = sizeof(*hdr);
871                         } else if (!strcmp(arg, "-v")) {
872                                 verbose = 1;
873                         } else if (!strcmp(arg, "-o")) {
874                                 if (index_name || (i+1) >= argc)
875                                         usage(index_pack_usage);
876                                 index_name = argv[++i];
877                         } else
878                                 usage(index_pack_usage);
879                         continue;
880                 }
881
882                 if (pack_name)
883                         usage(index_pack_usage);
884                 pack_name = arg;
885         }
886
887         if (!pack_name && !from_stdin)
888                 usage(index_pack_usage);
889         if (fix_thin_pack && !from_stdin)
890                 die("--fix-thin cannot be used without --stdin");
891         if (!index_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                 index_name_buf = xmalloc(len);
897                 memcpy(index_name_buf, pack_name, len - 5);
898                 strcpy(index_name_buf + len - 5, ".idx");
899                 index_name = index_name_buf;
900         }
901         if (keep_msg && !keep_name && pack_name) {
902                 int len = strlen(pack_name);
903                 if (!has_extension(pack_name, ".pack"))
904                         die("packfile name '%s' does not end with '.pack'",
905                             pack_name);
906                 keep_name_buf = xmalloc(len);
907                 memcpy(keep_name_buf, pack_name, len - 5);
908                 strcpy(keep_name_buf + len - 5, ".keep");
909                 keep_name = keep_name_buf;
910         }
911
912         curr_pack = open_pack_file(pack_name);
913         parse_pack_header();
914         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
915         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
916         if (verbose)
917                 setup_progress_signal();
918         parse_pack_objects(sha1);
919         if (nr_deltas != nr_resolved_deltas) {
920                 if (fix_thin_pack) {
921                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
922                         int nr_objects_initial = nr_objects;
923                         if (nr_unresolved <= 0)
924                                 die("confusion beyond insanity");
925                         objects = xrealloc(objects,
926                                            (nr_objects + nr_unresolved + 1)
927                                            * sizeof(*objects));
928                         fix_unresolved_deltas(nr_unresolved);
929                         if (verbose)
930                                 fprintf(stderr, "%d objects were added to complete this thin pack.\n",
931                                         nr_objects - nr_objects_initial);
932                         readjust_pack_header_and_sha1(sha1);
933                 }
934                 if (nr_deltas != nr_resolved_deltas)
935                         die("pack has %d unresolved deltas",
936                             nr_deltas - nr_resolved_deltas);
937         } else {
938                 /* Flush remaining pack final 20-byte SHA1. */
939                 flush();
940         }
941         free(deltas);
942         curr_index = write_index_file(index_name, sha1);
943         final(pack_name, curr_pack,
944                 index_name, curr_index,
945                 keep_name, keep_msg,
946                 sha1);
947         free(objects);
948         free(index_name_buf);
949         free(keep_name_buf);
950
951         return 0;
952 }