git-merge: fail correctly when we cannot fast forward.
[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/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         SHA_CTX ctx;
351         char header[50];
352         int header_size;
353         const char *type_str;
354
355         switch (type) {
356         case OBJ_COMMIT: type_str = commit_type; break;
357         case OBJ_TREE:   type_str = tree_type; break;
358         case OBJ_BLOB:   type_str = blob_type; break;
359         case OBJ_TAG:    type_str = tag_type; break;
360         default:
361                 die("bad type %d", type);
362         }
363
364         header_size = sprintf(header, "%s %lu", type_str, size) + 1;
365
366         SHA1_Init(&ctx);
367         SHA1_Update(&ctx, header, header_size);
368         SHA1_Update(&ctx, data, size);
369         SHA1_Final(sha1, &ctx);
370 }
371
372 static void resolve_delta(struct object_entry *delta_obj, void *base_data,
373                           unsigned long base_size, enum object_type type)
374 {
375         void *delta_data;
376         unsigned long delta_size;
377         void *result;
378         unsigned long result_size;
379         union delta_base delta_base;
380         int j, first, last;
381
382         delta_obj->real_type = type;
383         delta_data = get_data_from_pack(delta_obj);
384         delta_size = delta_obj->size;
385         result = patch_delta(base_data, base_size, delta_data, delta_size,
386                              &result_size);
387         free(delta_data);
388         if (!result)
389                 bad_object(delta_obj->offset, "failed to apply delta");
390         sha1_object(result, result_size, type, delta_obj->sha1);
391         nr_resolved_deltas++;
392
393         hashcpy(delta_base.sha1, delta_obj->sha1);
394         if (!find_delta_children(&delta_base, &first, &last)) {
395                 for (j = first; j <= last; j++) {
396                         struct object_entry *child = objects + deltas[j].obj_no;
397                         if (child->real_type == OBJ_REF_DELTA)
398                                 resolve_delta(child, result, result_size, type);
399                 }
400         }
401
402         memset(&delta_base, 0, sizeof(delta_base));
403         delta_base.offset = delta_obj->offset;
404         if (!find_delta_children(&delta_base, &first, &last)) {
405                 for (j = first; j <= last; j++) {
406                         struct object_entry *child = objects + deltas[j].obj_no;
407                         if (child->real_type == OBJ_OFS_DELTA)
408                                 resolve_delta(child, result, result_size, type);
409                 }
410         }
411
412         free(result);
413 }
414
415 static int compare_delta_entry(const void *a, const void *b)
416 {
417         const struct delta_entry *delta_a = a;
418         const struct delta_entry *delta_b = b;
419         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
420 }
421
422 /* Parse all objects and return the pack content SHA1 hash */
423 static void parse_pack_objects(unsigned char *sha1)
424 {
425         int i, percent = -1;
426         struct delta_entry *delta = deltas;
427         void *data;
428         struct stat st;
429
430         /*
431          * First pass:
432          * - find locations of all objects;
433          * - calculate SHA1 of all non-delta objects;
434          * - remember base (SHA1 or offset) for all deltas.
435          */
436         if (verbose)
437                 fprintf(stderr, "Indexing %d objects.\n", nr_objects);
438         for (i = 0; i < nr_objects; i++) {
439                 struct object_entry *obj = &objects[i];
440                 data = unpack_raw_entry(obj, &delta->base);
441                 obj->real_type = obj->type;
442                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
443                         nr_deltas++;
444                         delta->obj_no = i;
445                         delta++;
446                 } else
447                         sha1_object(data, obj->size, obj->type, obj->sha1);
448                 free(data);
449                 if (verbose)
450                         percent = display_progress(i+1, nr_objects, percent);
451         }
452         objects[i].offset = consumed_bytes;
453         if (verbose)
454                 fputc('\n', stderr);
455
456         /* Check pack integrity */
457         flush();
458         SHA1_Final(sha1, &input_ctx);
459         if (hashcmp(fill(20), sha1))
460                 die("pack is corrupted (SHA1 mismatch)");
461         use(20);
462
463         /* If input_fd is a file, we should have reached its end now. */
464         if (fstat(input_fd, &st))
465                 die("cannot fstat packfile: %s", strerror(errno));
466         if (S_ISREG(st.st_mode) && st.st_size != consumed_bytes)
467                 die("pack has junk at the end");
468
469         if (!nr_deltas)
470                 return;
471
472         /* Sort deltas by base SHA1/offset for fast searching */
473         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
474               compare_delta_entry);
475
476         /*
477          * Second pass:
478          * - for all non-delta objects, look if it is used as a base for
479          *   deltas;
480          * - if used as a base, uncompress the object and apply all deltas,
481          *   recursively checking if the resulting object is used as a base
482          *   for some more deltas.
483          */
484         if (verbose)
485                 fprintf(stderr, "Resolving %d deltas.\n", nr_deltas);
486         for (i = 0; i < nr_objects; i++) {
487                 struct object_entry *obj = &objects[i];
488                 union delta_base base;
489                 int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
490
491                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
492                         continue;
493                 hashcpy(base.sha1, obj->sha1);
494                 ref = !find_delta_children(&base, &ref_first, &ref_last);
495                 memset(&base, 0, sizeof(base));
496                 base.offset = obj->offset;
497                 ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
498                 if (!ref && !ofs)
499                         continue;
500                 data = get_data_from_pack(obj);
501                 if (ref)
502                         for (j = ref_first; j <= ref_last; j++) {
503                                 struct object_entry *child = objects + deltas[j].obj_no;
504                                 if (child->real_type == OBJ_REF_DELTA)
505                                         resolve_delta(child, data,
506                                                       obj->size, obj->type);
507                         }
508                 if (ofs)
509                         for (j = ofs_first; j <= ofs_last; j++) {
510                                 struct object_entry *child = objects + deltas[j].obj_no;
511                                 if (child->real_type == OBJ_OFS_DELTA)
512                                         resolve_delta(child, data,
513                                                       obj->size, obj->type);
514                         }
515                 free(data);
516                 if (verbose)
517                         percent = display_progress(nr_resolved_deltas,
518                                                    nr_deltas, percent);
519         }
520         if (verbose && nr_resolved_deltas == nr_deltas)
521                 fputc('\n', stderr);
522 }
523
524 static int write_compressed(int fd, void *in, unsigned int size)
525 {
526         z_stream stream;
527         unsigned long maxsize;
528         void *out;
529
530         memset(&stream, 0, sizeof(stream));
531         deflateInit(&stream, zlib_compression_level);
532         maxsize = deflateBound(&stream, size);
533         out = xmalloc(maxsize);
534
535         /* Compress it */
536         stream.next_in = in;
537         stream.avail_in = size;
538         stream.next_out = out;
539         stream.avail_out = maxsize;
540         while (deflate(&stream, Z_FINISH) == Z_OK);
541         deflateEnd(&stream);
542
543         size = stream.total_out;
544         write_or_die(fd, out, size);
545         free(out);
546         return size;
547 }
548
549 static void append_obj_to_pack(void *buf,
550                                unsigned long size, enum object_type type)
551 {
552         struct object_entry *obj = &objects[nr_objects++];
553         unsigned char header[10];
554         unsigned long s = size;
555         int n = 0;
556         unsigned char c = (type << 4) | (s & 15);
557         s >>= 4;
558         while (s) {
559                 header[n++] = c | 0x80;
560                 c = s & 0x7f;
561                 s >>= 7;
562         }
563         header[n++] = c;
564         write_or_die(output_fd, header, n);
565         obj[1].offset = obj[0].offset + n;
566         obj[1].offset += write_compressed(output_fd, buf, size);
567         sha1_object(buf, size, type, obj->sha1);
568 }
569
570 static int delta_pos_compare(const void *_a, const void *_b)
571 {
572         struct delta_entry *a = *(struct delta_entry **)_a;
573         struct delta_entry *b = *(struct delta_entry **)_b;
574         return a->obj_no - b->obj_no;
575 }
576
577 static void fix_unresolved_deltas(int nr_unresolved)
578 {
579         struct delta_entry **sorted_by_pos;
580         int i, n = 0, percent = -1;
581
582         /*
583          * Since many unresolved deltas may well be themselves base objects
584          * for more unresolved deltas, we really want to include the
585          * smallest number of base objects that would cover as much delta
586          * as possible by picking the
587          * trunc deltas first, allowing for other deltas to resolve without
588          * additional base objects.  Since most base objects are to be found
589          * before deltas depending on them, a good heuristic is to start
590          * resolving deltas in the same order as their position in the pack.
591          */
592         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
593         for (i = 0; i < nr_deltas; i++) {
594                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
595                         continue;
596                 sorted_by_pos[n++] = &deltas[i];
597         }
598         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
599
600         for (i = 0; i < n; i++) {
601                 struct delta_entry *d = sorted_by_pos[i];
602                 void *data;
603                 unsigned long size;
604                 char type[10];
605                 enum object_type obj_type;
606                 int j, first, last;
607
608                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
609                         continue;
610                 data = read_sha1_file(d->base.sha1, type, &size);
611                 if (!data)
612                         continue;
613                 if      (!strcmp(type, blob_type))   obj_type = OBJ_BLOB;
614                 else if (!strcmp(type, tree_type))   obj_type = OBJ_TREE;
615                 else if (!strcmp(type, commit_type)) obj_type = OBJ_COMMIT;
616                 else if (!strcmp(type, tag_type))    obj_type = OBJ_TAG;
617                 else die("base object %s is of type '%s'",
618                          sha1_to_hex(d->base.sha1), type);
619
620                 find_delta_children(&d->base, &first, &last);
621                 for (j = first; j <= last; j++) {
622                         struct object_entry *child = objects + deltas[j].obj_no;
623                         if (child->real_type == OBJ_REF_DELTA)
624                                 resolve_delta(child, data, size, obj_type);
625                 }
626
627                 append_obj_to_pack(data, size, obj_type);
628                 free(data);
629                 if (verbose)
630                         percent = display_progress(nr_resolved_deltas,
631                                                    nr_deltas, percent);
632         }
633         free(sorted_by_pos);
634         if (verbose)
635                 fputc('\n', stderr);
636 }
637
638 static void readjust_pack_header_and_sha1(unsigned char *sha1)
639 {
640         struct pack_header hdr;
641         SHA_CTX ctx;
642         int size;
643
644         /* Rewrite pack header with updated object number */
645         if (lseek(output_fd, 0, SEEK_SET) != 0)
646                 die("cannot seek back: %s", strerror(errno));
647         if (read_in_full(output_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
648                 die("cannot read pack header back: %s", strerror(errno));
649         hdr.hdr_entries = htonl(nr_objects);
650         if (lseek(output_fd, 0, SEEK_SET) != 0)
651                 die("cannot seek back: %s", strerror(errno));
652         write_or_die(output_fd, &hdr, sizeof(hdr));
653         if (lseek(output_fd, 0, SEEK_SET) != 0)
654                 die("cannot seek back: %s", strerror(errno));
655
656         /* Recompute and store the new pack's SHA1 */
657         SHA1_Init(&ctx);
658         do {
659                 unsigned char *buf[4096];
660                 size = xread(output_fd, buf, sizeof(buf));
661                 if (size < 0)
662                         die("cannot read pack data back: %s", strerror(errno));
663                 SHA1_Update(&ctx, buf, size);
664         } while (size > 0);
665         SHA1_Final(sha1, &ctx);
666         write_or_die(output_fd, sha1, 20);
667 }
668
669 static int sha1_compare(const void *_a, const void *_b)
670 {
671         struct object_entry *a = *(struct object_entry **)_a;
672         struct object_entry *b = *(struct object_entry **)_b;
673         return hashcmp(a->sha1, b->sha1);
674 }
675
676 /*
677  * On entry *sha1 contains the pack content SHA1 hash, on exit it is
678  * the SHA1 hash of sorted object names.
679  */
680 static const char *write_index_file(const char *index_name, unsigned char *sha1)
681 {
682         struct sha1file *f;
683         struct object_entry **sorted_by_sha, **list, **last;
684         unsigned int array[256];
685         int i, fd;
686         SHA_CTX ctx;
687
688         if (nr_objects) {
689                 sorted_by_sha =
690                         xcalloc(nr_objects, sizeof(struct object_entry *));
691                 list = sorted_by_sha;
692                 last = sorted_by_sha + nr_objects;
693                 for (i = 0; i < nr_objects; ++i)
694                         sorted_by_sha[i] = &objects[i];
695                 qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
696                       sha1_compare);
697
698         }
699         else
700                 sorted_by_sha = list = last = NULL;
701
702         if (!index_name) {
703                 static char tmpfile[PATH_MAX];
704                 snprintf(tmpfile, sizeof(tmpfile),
705                          "%s/index_XXXXXX", get_object_directory());
706                 fd = mkstemp(tmpfile);
707                 index_name = xstrdup(tmpfile);
708         } else {
709                 unlink(index_name);
710                 fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
711         }
712         if (fd < 0)
713                 die("unable to create %s: %s", index_name, strerror(errno));
714         f = sha1fd(fd, index_name);
715
716         /*
717          * Write the first-level table (the list is sorted,
718          * but we use a 256-entry lookup to be able to avoid
719          * having to do eight extra binary search iterations).
720          */
721         for (i = 0; i < 256; i++) {
722                 struct object_entry **next = list;
723                 while (next < last) {
724                         struct object_entry *obj = *next;
725                         if (obj->sha1[0] != i)
726                                 break;
727                         next++;
728                 }
729                 array[i] = htonl(next - sorted_by_sha);
730                 list = next;
731         }
732         sha1write(f, array, 256 * sizeof(int));
733
734         /* recompute the SHA1 hash of sorted object names.
735          * currently pack-objects does not do this, but that
736          * can be fixed.
737          */
738         SHA1_Init(&ctx);
739         /*
740          * Write the actual SHA1 entries..
741          */
742         list = sorted_by_sha;
743         for (i = 0; i < nr_objects; i++) {
744                 struct object_entry *obj = *list++;
745                 unsigned int offset = htonl(obj->offset);
746                 sha1write(f, &offset, 4);
747                 sha1write(f, obj->sha1, 20);
748                 SHA1_Update(&ctx, obj->sha1, 20);
749         }
750         sha1write(f, sha1, 20);
751         sha1close(f, NULL, 1);
752         free(sorted_by_sha);
753         SHA1_Final(sha1, &ctx);
754         return index_name;
755 }
756
757 static void final(const char *final_pack_name, const char *curr_pack_name,
758                   const char *final_index_name, const char *curr_index_name,
759                   const char *keep_name, const char *keep_msg,
760                   unsigned char *sha1)
761 {
762         char *report = "pack";
763         char name[PATH_MAX];
764         int err;
765
766         if (!from_stdin) {
767                 close(input_fd);
768         } else {
769                 err = close(output_fd);
770                 if (err)
771                         die("error while closing pack file: %s", strerror(errno));
772                 chmod(curr_pack_name, 0444);
773         }
774
775         if (keep_msg) {
776                 int keep_fd, keep_msg_len = strlen(keep_msg);
777                 if (!keep_name) {
778                         snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
779                                  get_object_directory(), sha1_to_hex(sha1));
780                         keep_name = name;
781                 }
782                 keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
783                 if (keep_fd < 0) {
784                         if (errno != EEXIST)
785                                 die("cannot write keep file");
786                 } else {
787                         if (keep_msg_len > 0) {
788                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
789                                 write_or_die(keep_fd, "\n", 1);
790                         }
791                         close(keep_fd);
792                         report = "keep";
793                 }
794         }
795
796         if (final_pack_name != curr_pack_name) {
797                 if (!final_pack_name) {
798                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
799                                  get_object_directory(), sha1_to_hex(sha1));
800                         final_pack_name = name;
801                 }
802                 if (move_temp_to_file(curr_pack_name, final_pack_name))
803                         die("cannot store pack file");
804         }
805
806         chmod(curr_index_name, 0444);
807         if (final_index_name != curr_index_name) {
808                 if (!final_index_name) {
809                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
810                                  get_object_directory(), sha1_to_hex(sha1));
811                         final_index_name = name;
812                 }
813                 if (move_temp_to_file(curr_index_name, final_index_name))
814                         die("cannot store index file");
815         }
816
817         if (!from_stdin) {
818                 printf("%s\n", sha1_to_hex(sha1));
819         } else {
820                 char buf[48];
821                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
822                                    report, sha1_to_hex(sha1));
823                 write_or_die(1, buf, len);
824
825                 /*
826                  * Let's just mimic git-unpack-objects here and write
827                  * the last part of the input buffer to stdout.
828                  */
829                 while (input_len) {
830                         err = xwrite(1, input_buffer + input_offset, input_len);
831                         if (err <= 0)
832                                 break;
833                         input_len -= err;
834                         input_offset += err;
835                 }
836         }
837 }
838
839 int main(int argc, char **argv)
840 {
841         int i, fix_thin_pack = 0;
842         const char *curr_pack, *pack_name = NULL;
843         const char *curr_index, *index_name = NULL;
844         const char *keep_name = NULL, *keep_msg = NULL;
845         char *index_name_buf = NULL, *keep_name_buf = NULL;
846         unsigned char sha1[20];
847
848         for (i = 1; i < argc; i++) {
849                 const char *arg = argv[i];
850
851                 if (*arg == '-') {
852                         if (!strcmp(arg, "--stdin")) {
853                                 from_stdin = 1;
854                         } else if (!strcmp(arg, "--fix-thin")) {
855                                 fix_thin_pack = 1;
856                         } else if (!strcmp(arg, "--keep")) {
857                                 keep_msg = "";
858                         } else if (!strncmp(arg, "--keep=", 7)) {
859                                 keep_msg = arg + 7;
860                         } else if (!strncmp(arg, "--pack_header=", 14)) {
861                                 struct pack_header *hdr;
862                                 char *c;
863
864                                 hdr = (struct pack_header *)input_buffer;
865                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
866                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
867                                 if (*c != ',')
868                                         die("bad %s", arg);
869                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
870                                 if (*c)
871                                         die("bad %s", arg);
872                                 input_len = sizeof(*hdr);
873                         } else if (!strcmp(arg, "-v")) {
874                                 verbose = 1;
875                         } else if (!strcmp(arg, "-o")) {
876                                 if (index_name || (i+1) >= argc)
877                                         usage(index_pack_usage);
878                                 index_name = argv[++i];
879                         } else
880                                 usage(index_pack_usage);
881                         continue;
882                 }
883
884                 if (pack_name)
885                         usage(index_pack_usage);
886                 pack_name = arg;
887         }
888
889         if (!pack_name && !from_stdin)
890                 usage(index_pack_usage);
891         if (fix_thin_pack && !from_stdin)
892                 die("--fix-thin cannot be used without --stdin");
893         if (!index_name && pack_name) {
894                 int len = strlen(pack_name);
895                 if (!has_extension(pack_name, ".pack"))
896                         die("packfile name '%s' does not end with '.pack'",
897                             pack_name);
898                 index_name_buf = xmalloc(len);
899                 memcpy(index_name_buf, pack_name, len - 5);
900                 strcpy(index_name_buf + len - 5, ".idx");
901                 index_name = index_name_buf;
902         }
903         if (keep_msg && !keep_name && pack_name) {
904                 int len = strlen(pack_name);
905                 if (!has_extension(pack_name, ".pack"))
906                         die("packfile name '%s' does not end with '.pack'",
907                             pack_name);
908                 keep_name_buf = xmalloc(len);
909                 memcpy(keep_name_buf, pack_name, len - 5);
910                 strcpy(keep_name_buf + len - 5, ".keep");
911                 keep_name = keep_name_buf;
912         }
913
914         curr_pack = open_pack_file(pack_name);
915         parse_pack_header();
916         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
917         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
918         if (verbose)
919                 setup_progress_signal();
920         parse_pack_objects(sha1);
921         if (nr_deltas != nr_resolved_deltas) {
922                 if (fix_thin_pack) {
923                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
924                         int nr_objects_initial = nr_objects;
925                         if (nr_unresolved <= 0)
926                                 die("confusion beyond insanity");
927                         objects = xrealloc(objects,
928                                            (nr_objects + nr_unresolved + 1)
929                                            * sizeof(*objects));
930                         fix_unresolved_deltas(nr_unresolved);
931                         if (verbose)
932                                 fprintf(stderr, "%d objects were added to complete this thin pack.\n",
933                                         nr_objects - nr_objects_initial);
934                         readjust_pack_header_and_sha1(sha1);
935                 }
936                 if (nr_deltas != nr_resolved_deltas)
937                         die("pack has %d unresolved deltas",
938                             nr_deltas - nr_resolved_deltas);
939         } else {
940                 /* Flush remaining pack final 20-byte SHA1. */
941                 flush();
942         }
943         free(deltas);
944         curr_index = write_index_file(index_name, sha1);
945         final(pack_name, curr_pack,
946                 index_name, curr_index,
947                 keep_name, keep_msg,
948                 sha1);
949         free(objects);
950         free(index_name_buf);
951         free(keep_name_buf);
952
953         return 0;
954 }