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 #include "progress.h"
10
11 static const char index_pack_usage[] =
12 "git-index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
13
14 struct object_entry
15 {
16         off_t offset;
17         unsigned long size;
18         unsigned int hdr_size;
19         uint32_t crc32;
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         off_t 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 struct progress progress;
52
53 /* We always read in 4kB chunks. */
54 static unsigned char input_buffer[4096];
55 static unsigned int input_offset, input_len;
56 static off_t consumed_bytes;
57 static SHA_CTX input_ctx;
58 static uint32_t input_crc32;
59 static int input_fd, output_fd, pack_fd;
60
61 /* Discard current buffer used content. */
62 static void flush(void)
63 {
64         if (input_offset) {
65                 if (output_fd >= 0)
66                         write_or_die(output_fd, input_buffer, input_offset);
67                 SHA1_Update(&input_ctx, input_buffer, input_offset);
68                 memmove(input_buffer, input_buffer + input_offset, input_len);
69                 input_offset = 0;
70         }
71 }
72
73 /*
74  * Make sure at least "min" bytes are available in the buffer, and
75  * return the pointer to the buffer.
76  */
77 static void *fill(int min)
78 {
79         if (min <= input_len)
80                 return input_buffer + input_offset;
81         if (min > sizeof(input_buffer))
82                 die("cannot fill %d bytes", min);
83         flush();
84         do {
85                 ssize_t ret = xread(input_fd, input_buffer + input_len,
86                                 sizeof(input_buffer) - input_len);
87                 if (ret <= 0) {
88                         if (!ret)
89                                 die("early EOF");
90                         die("read error on input: %s", strerror(errno));
91                 }
92                 input_len += ret;
93         } while (input_len < min);
94         return input_buffer;
95 }
96
97 static void use(int bytes)
98 {
99         if (bytes > input_len)
100                 die("used more bytes than were available");
101         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
102         input_len -= bytes;
103         input_offset += bytes;
104
105         /* make sure off_t is sufficiently large not to wrap */
106         if (consumed_bytes > consumed_bytes + bytes)
107                 die("pack too large for current definition of off_t");
108         consumed_bytes += bytes;
109 }
110
111 static const char *open_pack_file(const char *pack_name)
112 {
113         if (from_stdin) {
114                 input_fd = 0;
115                 if (!pack_name) {
116                         static char tmpfile[PATH_MAX];
117                         snprintf(tmpfile, sizeof(tmpfile),
118                                  "%s/tmp_pack_XXXXXX", get_object_directory());
119                         output_fd = mkstemp(tmpfile);
120                         pack_name = xstrdup(tmpfile);
121                 } else
122                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
123                 if (output_fd < 0)
124                         die("unable to create %s: %s\n", pack_name, strerror(errno));
125                 pack_fd = output_fd;
126         } else {
127                 input_fd = open(pack_name, O_RDONLY);
128                 if (input_fd < 0)
129                         die("cannot open packfile '%s': %s",
130                             pack_name, strerror(errno));
131                 output_fd = -1;
132                 pack_fd = input_fd;
133         }
134         SHA1_Init(&input_ctx);
135         return pack_name;
136 }
137
138 static void parse_pack_header(void)
139 {
140         struct pack_header *hdr = fill(sizeof(struct pack_header));
141
142         /* Header consistency check */
143         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
144                 die("pack signature mismatch");
145         if (!pack_version_ok(hdr->hdr_version))
146                 die("pack version %d unsupported", ntohl(hdr->hdr_version));
147
148         nr_objects = ntohl(hdr->hdr_entries);
149         use(sizeof(struct pack_header));
150 }
151
152 static void bad_object(unsigned long offset, const char *format,
153                        ...) NORETURN __attribute__((format (printf, 2, 3)));
154
155 static void bad_object(unsigned long offset, const char *format, ...)
156 {
157         va_list params;
158         char buf[1024];
159
160         va_start(params, format);
161         vsnprintf(buf, sizeof(buf), format, params);
162         va_end(params);
163         die("pack has bad object at offset %lu: %s", offset, buf);
164 }
165
166 static void *unpack_entry_data(unsigned long offset, unsigned long size)
167 {
168         z_stream stream;
169         void *buf = xmalloc(size);
170
171         memset(&stream, 0, sizeof(stream));
172         stream.next_out = buf;
173         stream.avail_out = size;
174         stream.next_in = fill(1);
175         stream.avail_in = input_len;
176         inflateInit(&stream);
177
178         for (;;) {
179                 int ret = inflate(&stream, 0);
180                 use(input_len - stream.avail_in);
181                 if (stream.total_out == size && ret == Z_STREAM_END)
182                         break;
183                 if (ret != Z_OK)
184                         bad_object(offset, "inflate returned %d", ret);
185                 stream.next_in = fill(1);
186                 stream.avail_in = input_len;
187         }
188         inflateEnd(&stream);
189         return buf;
190 }
191
192 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
193 {
194         unsigned char *p, c;
195         unsigned long size;
196         off_t base_offset;
197         unsigned shift;
198         void *data;
199
200         obj->offset = consumed_bytes;
201         input_crc32 = crc32(0, Z_NULL, 0);
202
203         p = fill(1);
204         c = *p;
205         use(1);
206         obj->type = (c >> 4) & 7;
207         size = (c & 15);
208         shift = 4;
209         while (c & 0x80) {
210                 p = fill(1);
211                 c = *p;
212                 use(1);
213                 size += (c & 0x7fUL) << shift;
214                 shift += 7;
215         }
216         obj->size = size;
217
218         switch (obj->type) {
219         case OBJ_REF_DELTA:
220                 hashcpy(delta_base->sha1, fill(20));
221                 use(20);
222                 break;
223         case OBJ_OFS_DELTA:
224                 memset(delta_base, 0, sizeof(*delta_base));
225                 p = fill(1);
226                 c = *p;
227                 use(1);
228                 base_offset = c & 127;
229                 while (c & 128) {
230                         base_offset += 1;
231                         if (!base_offset || MSB(base_offset, 7))
232                                 bad_object(obj->offset, "offset value overflow for delta base object");
233                         p = fill(1);
234                         c = *p;
235                         use(1);
236                         base_offset = (base_offset << 7) + (c & 127);
237                 }
238                 delta_base->offset = obj->offset - base_offset;
239                 if (delta_base->offset >= obj->offset)
240                         bad_object(obj->offset, "delta base offset is out of bound");
241                 break;
242         case OBJ_COMMIT:
243         case OBJ_TREE:
244         case OBJ_BLOB:
245         case OBJ_TAG:
246                 break;
247         default:
248                 bad_object(obj->offset, "unknown object type %d", obj->type);
249         }
250         obj->hdr_size = consumed_bytes - obj->offset;
251
252         data = unpack_entry_data(obj->offset, obj->size);
253         obj->crc32 = input_crc32;
254         return data;
255 }
256
257 static void *get_data_from_pack(struct object_entry *obj)
258 {
259         unsigned long from = obj[0].offset + obj[0].hdr_size;
260         unsigned long len = obj[1].offset - from;
261         unsigned long rdy = 0;
262         unsigned char *src, *data;
263         z_stream stream;
264         int st;
265
266         src = xmalloc(len);
267         data = src;
268         do {
269                 ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
270                 if (n <= 0)
271                         die("cannot pread pack file: %s", strerror(errno));
272                 rdy += n;
273         } while (rdy < len);
274         data = xmalloc(obj->size);
275         memset(&stream, 0, sizeof(stream));
276         stream.next_out = data;
277         stream.avail_out = obj->size;
278         stream.next_in = src;
279         stream.avail_in = len;
280         inflateInit(&stream);
281         while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
282         inflateEnd(&stream);
283         if (st != Z_STREAM_END || stream.total_out != obj->size)
284                 die("serious inflate inconsistency");
285         free(src);
286         return data;
287 }
288
289 static int find_delta(const union delta_base *base)
290 {
291         int first = 0, last = nr_deltas;
292
293         while (first < last) {
294                 int next = (first + last) / 2;
295                 struct delta_entry *delta = &deltas[next];
296                 int cmp;
297
298                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
299                 if (!cmp)
300                         return next;
301                 if (cmp < 0) {
302                         last = next;
303                         continue;
304                 }
305                 first = next+1;
306         }
307         return -first-1;
308 }
309
310 static int find_delta_children(const union delta_base *base,
311                                int *first_index, int *last_index)
312 {
313         int first = find_delta(base);
314         int last = first;
315         int end = nr_deltas - 1;
316
317         if (first < 0)
318                 return -1;
319         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
320                 --first;
321         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
322                 ++last;
323         *first_index = first;
324         *last_index = last;
325         return 0;
326 }
327
328 static void sha1_object(const void *data, unsigned long size,
329                         enum object_type type, unsigned char *sha1)
330 {
331         hash_sha1_file(data, size, typename(type), sha1);
332         if (has_sha1_file(sha1)) {
333                 void *has_data;
334                 enum object_type has_type;
335                 unsigned long has_size;
336                 has_data = read_sha1_file(sha1, &has_type, &has_size);
337                 if (!has_data)
338                         die("cannot read existing object %s", sha1_to_hex(sha1));
339                 if (size != has_size || type != has_type ||
340                     memcmp(data, has_data, size) != 0)
341                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
342                 free(has_data);
343         }
344 }
345
346 static void resolve_delta(struct object_entry *delta_obj, void *base_data,
347                           unsigned long base_size, enum object_type type)
348 {
349         void *delta_data;
350         unsigned long delta_size;
351         void *result;
352         unsigned long result_size;
353         union delta_base delta_base;
354         int j, first, last;
355
356         delta_obj->real_type = type;
357         delta_data = get_data_from_pack(delta_obj);
358         delta_size = delta_obj->size;
359         result = patch_delta(base_data, base_size, delta_data, delta_size,
360                              &result_size);
361         free(delta_data);
362         if (!result)
363                 bad_object(delta_obj->offset, "failed to apply delta");
364         sha1_object(result, result_size, type, delta_obj->sha1);
365         nr_resolved_deltas++;
366
367         hashcpy(delta_base.sha1, delta_obj->sha1);
368         if (!find_delta_children(&delta_base, &first, &last)) {
369                 for (j = first; j <= last; j++) {
370                         struct object_entry *child = objects + deltas[j].obj_no;
371                         if (child->real_type == OBJ_REF_DELTA)
372                                 resolve_delta(child, result, result_size, type);
373                 }
374         }
375
376         memset(&delta_base, 0, sizeof(delta_base));
377         delta_base.offset = delta_obj->offset;
378         if (!find_delta_children(&delta_base, &first, &last)) {
379                 for (j = first; j <= last; j++) {
380                         struct object_entry *child = objects + deltas[j].obj_no;
381                         if (child->real_type == OBJ_OFS_DELTA)
382                                 resolve_delta(child, result, result_size, type);
383                 }
384         }
385
386         free(result);
387 }
388
389 static int compare_delta_entry(const void *a, const void *b)
390 {
391         const struct delta_entry *delta_a = a;
392         const struct delta_entry *delta_b = b;
393         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
394 }
395
396 /* Parse all objects and return the pack content SHA1 hash */
397 static void parse_pack_objects(unsigned char *sha1)
398 {
399         int i;
400         struct delta_entry *delta = deltas;
401         void *data;
402         struct stat st;
403
404         /*
405          * First pass:
406          * - find locations of all objects;
407          * - calculate SHA1 of all non-delta objects;
408          * - remember base (SHA1 or offset) for all deltas.
409          */
410         if (verbose)
411                 start_progress(&progress, "Indexing %u objects...", "", nr_objects);
412         for (i = 0; i < nr_objects; i++) {
413                 struct object_entry *obj = &objects[i];
414                 data = unpack_raw_entry(obj, &delta->base);
415                 obj->real_type = obj->type;
416                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
417                         nr_deltas++;
418                         delta->obj_no = i;
419                         delta++;
420                 } else
421                         sha1_object(data, obj->size, obj->type, obj->sha1);
422                 free(data);
423                 if (verbose)
424                         display_progress(&progress, i+1);
425         }
426         objects[i].offset = consumed_bytes;
427         if (verbose)
428                 stop_progress(&progress);
429
430         /* Check pack integrity */
431         flush();
432         SHA1_Final(sha1, &input_ctx);
433         if (hashcmp(fill(20), sha1))
434                 die("pack is corrupted (SHA1 mismatch)");
435         use(20);
436
437         /* If input_fd is a file, we should have reached its end now. */
438         if (fstat(input_fd, &st))
439                 die("cannot fstat packfile: %s", strerror(errno));
440         if (S_ISREG(st.st_mode) &&
441                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
442                 die("pack has junk at the end");
443
444         if (!nr_deltas)
445                 return;
446
447         /* Sort deltas by base SHA1/offset for fast searching */
448         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
449               compare_delta_entry);
450
451         /*
452          * Second pass:
453          * - for all non-delta objects, look if it is used as a base for
454          *   deltas;
455          * - if used as a base, uncompress the object and apply all deltas,
456          *   recursively checking if the resulting object is used as a base
457          *   for some more deltas.
458          */
459         if (verbose)
460                 start_progress(&progress, "Resolving %u deltas...", "", nr_deltas);
461         for (i = 0; i < nr_objects; i++) {
462                 struct object_entry *obj = &objects[i];
463                 union delta_base base;
464                 int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
465
466                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
467                         continue;
468                 hashcpy(base.sha1, obj->sha1);
469                 ref = !find_delta_children(&base, &ref_first, &ref_last);
470                 memset(&base, 0, sizeof(base));
471                 base.offset = obj->offset;
472                 ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
473                 if (!ref && !ofs)
474                         continue;
475                 data = get_data_from_pack(obj);
476                 if (ref)
477                         for (j = ref_first; j <= ref_last; j++) {
478                                 struct object_entry *child = objects + deltas[j].obj_no;
479                                 if (child->real_type == OBJ_REF_DELTA)
480                                         resolve_delta(child, data,
481                                                       obj->size, obj->type);
482                         }
483                 if (ofs)
484                         for (j = ofs_first; j <= ofs_last; j++) {
485                                 struct object_entry *child = objects + deltas[j].obj_no;
486                                 if (child->real_type == OBJ_OFS_DELTA)
487                                         resolve_delta(child, data,
488                                                       obj->size, obj->type);
489                         }
490                 free(data);
491                 if (verbose)
492                         display_progress(&progress, nr_resolved_deltas);
493         }
494 }
495
496 static int write_compressed(int fd, void *in, unsigned int size, uint32_t *obj_crc)
497 {
498         z_stream stream;
499         unsigned long maxsize;
500         void *out;
501
502         memset(&stream, 0, sizeof(stream));
503         deflateInit(&stream, zlib_compression_level);
504         maxsize = deflateBound(&stream, size);
505         out = xmalloc(maxsize);
506
507         /* Compress it */
508         stream.next_in = in;
509         stream.avail_in = size;
510         stream.next_out = out;
511         stream.avail_out = maxsize;
512         while (deflate(&stream, Z_FINISH) == Z_OK);
513         deflateEnd(&stream);
514
515         size = stream.total_out;
516         write_or_die(fd, out, size);
517         *obj_crc = crc32(*obj_crc, out, size);
518         free(out);
519         return size;
520 }
521
522 static void append_obj_to_pack(const unsigned char *sha1, void *buf,
523                                unsigned long size, enum object_type type)
524 {
525         struct object_entry *obj = &objects[nr_objects++];
526         unsigned char header[10];
527         unsigned long s = size;
528         int n = 0;
529         unsigned char c = (type << 4) | (s & 15);
530         s >>= 4;
531         while (s) {
532                 header[n++] = c | 0x80;
533                 c = s & 0x7f;
534                 s >>= 7;
535         }
536         header[n++] = c;
537         write_or_die(output_fd, header, n);
538         obj[0].crc32 = crc32(0, Z_NULL, 0);
539         obj[0].crc32 = crc32(obj[0].crc32, header, n);
540         obj[1].offset = obj[0].offset + n;
541         obj[1].offset += write_compressed(output_fd, buf, size, &obj[0].crc32);
542         hashcpy(obj->sha1, sha1);
543 }
544
545 static int delta_pos_compare(const void *_a, const void *_b)
546 {
547         struct delta_entry *a = *(struct delta_entry **)_a;
548         struct delta_entry *b = *(struct delta_entry **)_b;
549         return a->obj_no - b->obj_no;
550 }
551
552 static void fix_unresolved_deltas(int nr_unresolved)
553 {
554         struct delta_entry **sorted_by_pos;
555         int i, n = 0;
556
557         /*
558          * Since many unresolved deltas may well be themselves base objects
559          * for more unresolved deltas, we really want to include the
560          * smallest number of base objects that would cover as much delta
561          * as possible by picking the
562          * trunc deltas first, allowing for other deltas to resolve without
563          * additional base objects.  Since most base objects are to be found
564          * before deltas depending on them, a good heuristic is to start
565          * resolving deltas in the same order as their position in the pack.
566          */
567         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
568         for (i = 0; i < nr_deltas; i++) {
569                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
570                         continue;
571                 sorted_by_pos[n++] = &deltas[i];
572         }
573         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
574
575         for (i = 0; i < n; i++) {
576                 struct delta_entry *d = sorted_by_pos[i];
577                 void *data;
578                 unsigned long size;
579                 enum object_type type;
580                 int j, first, last;
581
582                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
583                         continue;
584                 data = read_sha1_file(d->base.sha1, &type, &size);
585                 if (!data)
586                         continue;
587
588                 find_delta_children(&d->base, &first, &last);
589                 for (j = first; j <= last; j++) {
590                         struct object_entry *child = objects + deltas[j].obj_no;
591                         if (child->real_type == OBJ_REF_DELTA)
592                                 resolve_delta(child, data, size, type);
593                 }
594
595                 if (check_sha1_signature(d->base.sha1, data, size, typename(type)))
596                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
597                 append_obj_to_pack(d->base.sha1, data, size, type);
598                 free(data);
599                 if (verbose)
600                         display_progress(&progress, nr_resolved_deltas);
601         }
602         free(sorted_by_pos);
603 }
604
605 static uint32_t index_default_version = 1;
606 static uint32_t index_off32_limit = 0x7fffffff;
607
608 static int sha1_compare(const void *_a, const void *_b)
609 {
610         struct object_entry *a = *(struct object_entry **)_a;
611         struct object_entry *b = *(struct object_entry **)_b;
612         return hashcmp(a->sha1, b->sha1);
613 }
614
615 /*
616  * On entry *sha1 contains the pack content SHA1 hash, on exit it is
617  * the SHA1 hash of sorted object names.
618  */
619 static const char *write_index_file(const char *index_name, unsigned char *sha1)
620 {
621         struct sha1file *f;
622         struct object_entry **sorted_by_sha, **list, **last;
623         uint32_t array[256];
624         int i, fd;
625         SHA_CTX ctx;
626         uint32_t index_version;
627
628         if (nr_objects) {
629                 sorted_by_sha =
630                         xcalloc(nr_objects, sizeof(struct object_entry *));
631                 list = sorted_by_sha;
632                 last = sorted_by_sha + nr_objects;
633                 for (i = 0; i < nr_objects; ++i)
634                         sorted_by_sha[i] = &objects[i];
635                 qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
636                       sha1_compare);
637         }
638         else
639                 sorted_by_sha = list = last = NULL;
640
641         if (!index_name) {
642                 static char tmpfile[PATH_MAX];
643                 snprintf(tmpfile, sizeof(tmpfile),
644                          "%s/tmp_idx_XXXXXX", get_object_directory());
645                 fd = mkstemp(tmpfile);
646                 index_name = xstrdup(tmpfile);
647         } else {
648                 unlink(index_name);
649                 fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
650         }
651         if (fd < 0)
652                 die("unable to create %s: %s", index_name, strerror(errno));
653         f = sha1fd(fd, index_name);
654
655         /* if last object's offset is >= 2^31 we should use index V2 */
656         index_version = (objects[nr_objects-1].offset >> 31) ? 2 : index_default_version;
657
658         /* index versions 2 and above need a header */
659         if (index_version >= 2) {
660                 struct pack_idx_header hdr;
661                 hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
662                 hdr.idx_version = htonl(index_version);
663                 sha1write(f, &hdr, sizeof(hdr));
664         }
665
666         /*
667          * Write the first-level table (the list is sorted,
668          * but we use a 256-entry lookup to be able to avoid
669          * having to do eight extra binary search iterations).
670          */
671         for (i = 0; i < 256; i++) {
672                 struct object_entry **next = list;
673                 while (next < last) {
674                         struct object_entry *obj = *next;
675                         if (obj->sha1[0] != i)
676                                 break;
677                         next++;
678                 }
679                 array[i] = htonl(next - sorted_by_sha);
680                 list = next;
681         }
682         sha1write(f, array, 256 * 4);
683
684         /* compute the SHA1 hash of sorted object names. */
685         SHA1_Init(&ctx);
686
687         /*
688          * Write the actual SHA1 entries..
689          */
690         list = sorted_by_sha;
691         for (i = 0; i < nr_objects; i++) {
692                 struct object_entry *obj = *list++;
693                 if (index_version < 2) {
694                         uint32_t offset = htonl(obj->offset);
695                         sha1write(f, &offset, 4);
696                 }
697                 sha1write(f, obj->sha1, 20);
698                 SHA1_Update(&ctx, obj->sha1, 20);
699         }
700
701         if (index_version >= 2) {
702                 unsigned int nr_large_offset = 0;
703
704                 /* write the crc32 table */
705                 list = sorted_by_sha;
706                 for (i = 0; i < nr_objects; i++) {
707                         struct object_entry *obj = *list++;
708                         uint32_t crc32_val = htonl(obj->crc32);
709                         sha1write(f, &crc32_val, 4);
710                 }
711
712                 /* write the 32-bit offset table */
713                 list = sorted_by_sha;
714                 for (i = 0; i < nr_objects; i++) {
715                         struct object_entry *obj = *list++;
716                         uint32_t offset = (obj->offset <= index_off32_limit) ?
717                                 obj->offset : (0x80000000 | nr_large_offset++);
718                         offset = htonl(offset);
719                         sha1write(f, &offset, 4);
720                 }
721
722                 /* write the large offset table */
723                 list = sorted_by_sha;
724                 while (nr_large_offset) {
725                         struct object_entry *obj = *list++;
726                         uint64_t offset = obj->offset;
727                         if (offset > index_off32_limit) {
728                                 uint32_t split[2];
729                                 split[0]        = htonl(offset >> 32);
730                                 split[1] = htonl(offset & 0xffffffff);
731                                 sha1write(f, split, 8);
732                                 nr_large_offset--;
733                         }
734                 }
735         }
736
737         sha1write(f, sha1, 20);
738         sha1close(f, NULL, 1);
739         free(sorted_by_sha);
740         SHA1_Final(sha1, &ctx);
741         return index_name;
742 }
743
744 static void final(const char *final_pack_name, const char *curr_pack_name,
745                   const char *final_index_name, const char *curr_index_name,
746                   const char *keep_name, const char *keep_msg,
747                   unsigned char *sha1)
748 {
749         const char *report = "pack";
750         char name[PATH_MAX];
751         int err;
752
753         if (!from_stdin) {
754                 close(input_fd);
755         } else {
756                 err = close(output_fd);
757                 if (err)
758                         die("error while closing pack file: %s", strerror(errno));
759                 chmod(curr_pack_name, 0444);
760         }
761
762         if (keep_msg) {
763                 int keep_fd, keep_msg_len = strlen(keep_msg);
764                 if (!keep_name) {
765                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
766                                  get_object_directory(), sha1_to_hex(sha1));
767                         keep_name = name;
768                 }
769                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
770                 if (keep_fd < 0) {
771                         if (errno != EEXIST)
772                                 die("cannot write keep file");
773                 } else {
774                         if (keep_msg_len > 0) {
775                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
776                                 write_or_die(keep_fd, "\n", 1);
777                         }
778                         close(keep_fd);
779                         report = "keep";
780                 }
781         }
782
783         if (final_pack_name != curr_pack_name) {
784                 if (!final_pack_name) {
785                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
786                                  get_object_directory(), sha1_to_hex(sha1));
787                         final_pack_name = name;
788                 }
789                 if (move_temp_to_file(curr_pack_name, final_pack_name))
790                         die("cannot store pack file");
791         }
792
793         chmod(curr_index_name, 0444);
794         if (final_index_name != curr_index_name) {
795                 if (!final_index_name) {
796                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
797                                  get_object_directory(), sha1_to_hex(sha1));
798                         final_index_name = name;
799                 }
800                 if (move_temp_to_file(curr_index_name, final_index_name))
801                         die("cannot store index file");
802         }
803
804         if (!from_stdin) {
805                 printf("%s\n", sha1_to_hex(sha1));
806         } else {
807                 char buf[48];
808                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
809                                    report, sha1_to_hex(sha1));
810                 write_or_die(1, buf, len);
811
812                 /*
813                  * Let's just mimic git-unpack-objects here and write
814                  * the last part of the input buffer to stdout.
815                  */
816                 while (input_len) {
817                         err = xwrite(1, input_buffer + input_offset, input_len);
818                         if (err <= 0)
819                                 break;
820                         input_len -= err;
821                         input_offset += err;
822                 }
823         }
824 }
825
826 int main(int argc, char **argv)
827 {
828         int i, fix_thin_pack = 0;
829         const char *curr_pack, *pack_name = NULL;
830         const char *curr_index, *index_name = NULL;
831         const char *keep_name = NULL, *keep_msg = NULL;
832         char *index_name_buf = NULL, *keep_name_buf = NULL;
833         unsigned char sha1[20];
834
835         for (i = 1; i < argc; i++) {
836                 const char *arg = argv[i];
837
838                 if (*arg == '-') {
839                         if (!strcmp(arg, "--stdin")) {
840                                 from_stdin = 1;
841                         } else if (!strcmp(arg, "--fix-thin")) {
842                                 fix_thin_pack = 1;
843                         } else if (!strcmp(arg, "--keep")) {
844                                 keep_msg = "";
845                         } else if (!prefixcmp(arg, "--keep=")) {
846                                 keep_msg = arg + 7;
847                         } else if (!prefixcmp(arg, "--pack_header=")) {
848                                 struct pack_header *hdr;
849                                 char *c;
850
851                                 hdr = (struct pack_header *)input_buffer;
852                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
853                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
854                                 if (*c != ',')
855                                         die("bad %s", arg);
856                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
857                                 if (*c)
858                                         die("bad %s", arg);
859                                 input_len = sizeof(*hdr);
860                         } else if (!strcmp(arg, "-v")) {
861                                 verbose = 1;
862                         } else if (!strcmp(arg, "-o")) {
863                                 if (index_name || (i+1) >= argc)
864                                         usage(index_pack_usage);
865                                 index_name = argv[++i];
866                         } else if (!prefixcmp(arg, "--index-version=")) {
867                                 char *c;
868                                 index_default_version = strtoul(arg + 16, &c, 10);
869                                 if (index_default_version > 2)
870                                         die("bad %s", arg);
871                                 if (*c == ',')
872                                         index_off32_limit = strtoul(c+1, &c, 0);
873                                 if (*c || index_off32_limit & 0x80000000)
874                                         die("bad %s", arg);
875                         } else
876                                 usage(index_pack_usage);
877                         continue;
878                 }
879
880                 if (pack_name)
881                         usage(index_pack_usage);
882                 pack_name = arg;
883         }
884
885         if (!pack_name && !from_stdin)
886                 usage(index_pack_usage);
887         if (fix_thin_pack && !from_stdin)
888                 die("--fix-thin cannot be used without --stdin");
889         if (!index_name && pack_name) {
890                 int len = strlen(pack_name);
891                 if (!has_extension(pack_name, ".pack"))
892                         die("packfile name '%s' does not end with '.pack'",
893                             pack_name);
894                 index_name_buf = xmalloc(len);
895                 memcpy(index_name_buf, pack_name, len - 5);
896                 strcpy(index_name_buf + len - 5, ".idx");
897                 index_name = index_name_buf;
898         }
899         if (keep_msg && !keep_name && pack_name) {
900                 int len = strlen(pack_name);
901                 if (!has_extension(pack_name, ".pack"))
902                         die("packfile name '%s' does not end with '.pack'",
903                             pack_name);
904                 keep_name_buf = xmalloc(len);
905                 memcpy(keep_name_buf, pack_name, len - 5);
906                 strcpy(keep_name_buf + len - 5, ".keep");
907                 keep_name = keep_name_buf;
908         }
909
910         curr_pack = open_pack_file(pack_name);
911         parse_pack_header();
912         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
913         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
914         parse_pack_objects(sha1);
915         if (nr_deltas == nr_resolved_deltas) {
916                 if (verbose)
917                         stop_progress(&progress);
918                 /* Flush remaining pack final 20-byte SHA1. */
919                 flush();
920         } else {
921                 if (fix_thin_pack) {
922                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
923                         int nr_objects_initial = nr_objects;
924                         if (nr_unresolved <= 0)
925                                 die("confusion beyond insanity");
926                         objects = xrealloc(objects,
927                                            (nr_objects + nr_unresolved + 1)
928                                            * sizeof(*objects));
929                         fix_unresolved_deltas(nr_unresolved);
930                         if (verbose) {
931                                 stop_progress(&progress);
932                                 fprintf(stderr, "%d objects were added to complete this thin pack.\n",
933                                         nr_objects - nr_objects_initial);
934                         }
935                         fixup_pack_header_footer(output_fd, sha1,
936                                 curr_pack, nr_objects);
937                 }
938                 if (nr_deltas != nr_resolved_deltas)
939                         die("pack has %d unresolved deltas",
940                             nr_deltas - nr_resolved_deltas);
941         }
942         free(deltas);
943         curr_index = write_index_file(index_name, sha1);
944         final(pack_name, curr_pack,
945                 index_name, curr_index,
946                 keep_name, keep_msg,
947                 sha1);
948         free(objects);
949         free(index_name_buf);
950         free(keep_name_buf);
951
952         return 0;
953 }