builtin-index-pack.c

   1 #include "cache.h"
   2 #include "delta.h"
   3 #include "pack.h"
   4 #include "csum-file.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "progress.h"
  10 #include "fsck.h"
  11 #include "exec_cmd.h"
  12
  13 static const char index_pack_usage[] =
  14 "git index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] [--strict] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
  15
  16 struct object_entry
  17 {
  18         struct pack_idx_entry idx;
  19         unsigned long size;
  20         unsigned int hdr_size;
  21         enum object_type type;
  22         enum object_type real_type;
  23 };
  24
  25 union delta_base {
  26         unsigned char sha1[20];
  27         off_t offset;
  28 };
  29
  30 struct base_data {
  31         struct base_data *base;
  32         struct base_data *child;
  33         struct object_entry *obj;
  34         void *data;
  35         unsigned long size;
  36 };
  37
  38 /*
  39  * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  40  * to memcmp() only the first 20 bytes.
  41  */
  42 #define UNION_BASE_SZ   20
  43
  44 #define FLAG_LINK (1u<<20)
  45 #define FLAG_CHECKED (1u<<21)
  46
  47 struct delta_entry
  48 {
  49         union delta_base base;
  50         int obj_no;
  51 };
  52
  53 static struct object_entry *objects;
  54 static struct delta_entry *deltas;
  55 static struct base_data *base_cache;
  56 static size_t base_cache_used;
  57 static int nr_objects;
  58 static int nr_deltas;
  59 static int nr_resolved_deltas;
  60
  61 static int from_stdin;
  62 static int strict;
  63 static int verbose;
  64
  65 static struct progress *progress;
  66
  67 /* We always read in 4kB chunks. */
  68 static unsigned char input_buffer[4096];
  69 static unsigned int input_offset, input_len;
  70 static off_t consumed_bytes;
  71 static git_SHA_CTX input_ctx;
  72 static uint32_t input_crc32;
  73 static int input_fd, output_fd, pack_fd;
  74
  75 static int mark_link(struct object *obj, int type, void *data)
  76 {
  77         if (!obj)
  78                 return -1;
  79
  80         if (type != OBJ_ANY && obj->type != type)
  81                 die("object type mismatch at %s", sha1_to_hex(obj->sha1));
  82
  83         obj->flags |= FLAG_LINK;
  84         return 0;
  85 }
  86
  87 /* The content of each linked object must have been checked
  88    or it must be already present in the object database */
  89 static void check_object(struct object *obj)
  90 {
  91         if (!obj)
  92                 return;
  93
  94         if (!(obj->flags & FLAG_LINK))
  95                 return;
  96
  97         if (!(obj->flags & FLAG_CHECKED)) {
  98                 unsigned long size;
  99                 int type = sha1_object_info(obj->sha1, &size);
 100                 if (type != obj->type || type <= 0)
 101                         die("object of unexpected type");
 102                 obj->flags |= FLAG_CHECKED;
 103                 return;
 104         }
 105 }
 106
 107 static void check_objects(void)
 108 {
 109         unsigned i, max;
 110
 111         max = get_max_object_index();
 112         for (i = 0; i < max; i++)
 113                 check_object(get_indexed_object(i));
 114 }
 115
 116
 117 /* Discard current buffer used content. */
 118 static void flush(void)
 119 {
 120         if (input_offset) {
 121                 if (output_fd >= 0)
 122                         write_or_die(output_fd, input_buffer, input_offset);
 123                 git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 124                 memmove(input_buffer, input_buffer + input_offset, input_len);
 125                 input_offset = 0;
 126         }
 127 }
 128
 129 /*
 130  * Make sure at least "min" bytes are available in the buffer, and
 131  * return the pointer to the buffer.
 132  */
 133 static void *fill(int min)
 134 {
 135         if (min <= input_len)
 136                 return input_buffer + input_offset;
 137         if (min > sizeof(input_buffer))
 138                 die("cannot fill %d bytes", min);
 139         flush();
 140         do {
 141                 ssize_t ret = xread(input_fd, input_buffer + input_len,
 142                                 sizeof(input_buffer) - input_len);
 143                 if (ret <= 0) {
 144                         if (!ret)
 145                                 die("early EOF");
 146                         die_errno("read error on input");
 147                 }
 148                 input_len += ret;
 149                 if (from_stdin)
 150                         display_throughput(progress, consumed_bytes + input_len);
 151         } while (input_len < min);
 152         return input_buffer;
 153 }
 154
 155 static void use(int bytes)
 156 {
 157         if (bytes > input_len)
 158                 die("used more bytes than were available");
 159         input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 160         input_len -= bytes;
 161         input_offset += bytes;
 162
 163         /* make sure off_t is sufficiently large not to wrap */
 164         if (consumed_bytes > consumed_bytes + bytes)
 165                 die("pack too large for current definition of off_t");
 166         consumed_bytes += bytes;
 167 }
 168
 169 static const char *open_pack_file(const char *pack_name)
 170 {
 171         if (from_stdin) {
 172                 input_fd = 0;
 173                 if (!pack_name) {
 174                         static char tmpfile[PATH_MAX];
 175                         output_fd = odb_mkstemp(tmpfile, sizeof(tmpfile),
 176                                                 "pack/tmp_pack_XXXXXX");
 177                         pack_name = xstrdup(tmpfile);
 178                 } else
 179                         output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 180                 if (output_fd < 0)
 181                         die_errno("unable to create '%s'", pack_name);
 182                 pack_fd = output_fd;
 183         } else {
 184                 input_fd = open(pack_name, O_RDONLY);
 185                 if (input_fd < 0)
 186                         die_errno("cannot open packfile '%s'", pack_name);
 187                 output_fd = -1;
 188                 pack_fd = input_fd;
 189         }
 190         git_SHA1_Init(&input_ctx);
 191         return pack_name;
 192 }
 193
 194 static void parse_pack_header(void)
 195 {
 196         struct pack_header *hdr = fill(sizeof(struct pack_header));
 197
 198         /* Header consistency check */
 199         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 200                 die("pack signature mismatch");
 201         if (!pack_version_ok(hdr->hdr_version))
 202                 die("pack version %"PRIu32" unsupported",
 203                         ntohl(hdr->hdr_version));
 204
 205         nr_objects = ntohl(hdr->hdr_entries);
 206         use(sizeof(struct pack_header));
 207 }
 208
 209 static NORETURN void bad_object(unsigned long offset, const char *format,
 210                        ...) __attribute__((format (printf, 2, 3)));
 211
 212 static void bad_object(unsigned long offset, const char *format, ...)
 213 {
 214         va_list params;
 215         char buf[1024];
 216
 217         va_start(params, format);
 218         vsnprintf(buf, sizeof(buf), format, params);
 219         va_end(params);
 220         die("pack has bad object at offset %lu: %s", offset, buf);
 221 }
 222
 223 static void free_base_data(struct base_data *c)
 224 {
 225         if (c->data) {
 226                 free(c->data);
 227                 c->data = NULL;
 228                 base_cache_used -= c->size;
 229         }
 230 }
 231
 232 static void prune_base_data(struct base_data *retain)
 233 {
 234         struct base_data *b;
 235         for (b = base_cache;
 236              base_cache_used > delta_base_cache_limit && b;
 237              b = b->child) {
 238                 if (b->data && b != retain)
 239                         free_base_data(b);
 240         }
 241 }
 242
 243 static void link_base_data(struct base_data *base, struct base_data *c)
 244 {
 245         if (base)
 246                 base->child = c;
 247         else
 248                 base_cache = c;
 249
 250         c->base = base;
 251         c->child = NULL;
 252         if (c->data)
 253                 base_cache_used += c->size;
 254         prune_base_data(c);
 255 }
 256
 257 static void unlink_base_data(struct base_data *c)
 258 {
 259         struct base_data *base = c->base;
 260         if (base)
 261                 base->child = NULL;
 262         else
 263                 base_cache = NULL;
 264         free_base_data(c);
 265 }
 266
 267 static void *unpack_entry_data(unsigned long offset, unsigned long size)
 268 {
 269         z_stream stream;
 270         void *buf = xmalloc(size);
 271
 272         memset(&stream, 0, sizeof(stream));
 273         stream.next_out = buf;
 274         stream.avail_out = size;
 275         stream.next_in = fill(1);
 276         stream.avail_in = input_len;
 277         git_inflate_init(&stream);
 278
 279         for (;;) {
 280                 int ret = git_inflate(&stream, 0);
 281                 use(input_len - stream.avail_in);
 282                 if (stream.total_out == size && ret == Z_STREAM_END)
 283                         break;
 284                 if (ret != Z_OK)
 285                         bad_object(offset, "inflate returned %d", ret);
 286                 stream.next_in = fill(1);
 287                 stream.avail_in = input_len;
 288         }
 289         git_inflate_end(&stream);
 290         return buf;
 291 }
 292
 293 static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 294 {
 295         unsigned char *p;
 296         unsigned long size, c;
 297         off_t base_offset;
 298         unsigned shift;
 299         void *data;
 300
 301         obj->idx.offset = consumed_bytes;
 302         input_crc32 = crc32(0, Z_NULL, 0);
 303
 304         p = fill(1);
 305         c = *p;
 306         use(1);
 307         obj->type = (c >> 4) & 7;
 308         size = (c & 15);
 309         shift = 4;
 310         while (c & 0x80) {
 311                 p = fill(1);
 312                 c = *p;
 313                 use(1);
 314                 size += (c & 0x7f) << shift;
 315                 shift += 7;
 316         }
 317         obj->size = size;
 318
 319         switch (obj->type) {
 320         case OBJ_REF_DELTA:
 321                 hashcpy(delta_base->sha1, fill(20));
 322                 use(20);
 323                 break;
 324         case OBJ_OFS_DELTA:
 325                 memset(delta_base, 0, sizeof(*delta_base));
 326                 p = fill(1);
 327                 c = *p;
 328                 use(1);
 329                 base_offset = c & 127;
 330                 while (c & 128) {
 331                         base_offset += 1;
 332                         if (!base_offset || MSB(base_offset, 7))
 333                                 bad_object(obj->idx.offset, "offset value overflow for delta base object");
 334                         p = fill(1);
 335                         c = *p;
 336                         use(1);
 337                         base_offset = (base_offset << 7) + (c & 127);
 338                 }
 339                 delta_base->offset = obj->idx.offset - base_offset;
 340                 if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
 341                         bad_object(obj->idx.offset, "delta base offset is out of bound");
 342                 break;
 343         case OBJ_COMMIT:
 344         case OBJ_TREE:
 345         case OBJ_BLOB:
 346         case OBJ_TAG:
 347                 break;
 348         default:
 349                 bad_object(obj->idx.offset, "unknown object type %d", obj->type);
 350         }
 351         obj->hdr_size = consumed_bytes - obj->idx.offset;
 352
 353         data = unpack_entry_data(obj->idx.offset, obj->size);
 354         obj->idx.crc32 = input_crc32;
 355         return data;
 356 }
 357
 358 static void *get_data_from_pack(struct object_entry *obj)
 359 {
 360         off_t from = obj[0].idx.offset + obj[0].hdr_size;
 361         unsigned long len = obj[1].idx.offset - from;
 362         unsigned char *data, *inbuf;
 363         z_stream stream;
 364         int status;
 365
 366         data = xmalloc(obj->size);
 367         inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
 368
 369         memset(&stream, 0, sizeof(stream));
 370         git_inflate_init(&stream);
 371         stream.next_out = data;
 372         stream.avail_out = obj->size;
 373
 374         do {
 375                 ssize_t n = (len < 64*1024) ? len : 64*1024;
 376                 n = pread(pack_fd, inbuf, n, from);
 377                 if (n < 0)
 378                         die_errno("cannot pread pack file");
 379                 if (!n)
 380                         die("premature end of pack file, %lu bytes missing", len);
 381                 from += n;
 382                 len -= n;
 383                 stream.next_in = inbuf;
 384                 stream.avail_in = n;
 385                 status = git_inflate(&stream, 0);
 386         } while (len && status == Z_OK && !stream.avail_in);
 387
 388         /* This has been inflated OK when first encountered, so... */
 389         if (status != Z_STREAM_END || stream.total_out != obj->size)
 390                 die("serious inflate inconsistency");
 391
 392         git_inflate_end(&stream);
 393         free(inbuf);
 394         return data;
 395 }
 396
 397 static int find_delta(const union delta_base *base)
 398 {
 399         int first = 0, last = nr_deltas;
 400
 401         while (first < last) {
 402                 int next = (first + last) / 2;
 403                 struct delta_entry *delta = &deltas[next];
 404                 int cmp;
 405
 406                 cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
 407                 if (!cmp)
 408                         return next;
 409                 if (cmp < 0) {
 410                         last = next;
 411                         continue;
 412                 }
 413                 first = next+1;
 414         }
 415         return -first-1;
 416 }
 417
 418 static void find_delta_children(const union delta_base *base,
 419                                 int *first_index, int *last_index)
 420 {
 421         int first = find_delta(base);
 422         int last = first;
 423         int end = nr_deltas - 1;
 424
 425         if (first < 0) {
 426                 *first_index = 0;
 427                 *last_index = -1;
 428                 return;
 429         }
 430         while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 431                 --first;
 432         while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 433                 ++last;
 434         *first_index = first;
 435         *last_index = last;
 436 }
 437
 438 static void sha1_object(const void *data, unsigned long size,
 439                         enum object_type type, unsigned char *sha1)
 440 {
 441         hash_sha1_file(data, size, typename(type), sha1);
 442         if (has_sha1_file(sha1)) {
 443                 void *has_data;
 444                 enum object_type has_type;
 445                 unsigned long has_size;
 446                 has_data = read_sha1_file(sha1, &has_type, &has_size);
 447                 if (!has_data)
 448                         die("cannot read existing object %s", sha1_to_hex(sha1));
 449                 if (size != has_size || type != has_type ||
 450                     memcmp(data, has_data, size) != 0)
 451                         die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
 452                 free(has_data);
 453         }
 454         if (strict) {
 455                 if (type == OBJ_BLOB) {
 456                         struct blob *blob = lookup_blob(sha1);
 457                         if (blob)
 458                                 blob->object.flags |= FLAG_CHECKED;
 459                         else
 460                                 die("invalid blob object %s", sha1_to_hex(sha1));
 461                 } else {
 462                         struct object *obj;
 463                         int eaten;
 464                         void *buf = (void *) data;
 465
 466                         /*
 467                          * we do not need to free the memory here, as the
 468                          * buf is deleted by the caller.
 469                          */
 470                         obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 471                         if (!obj)
 472                                 die("invalid %s", typename(type));
 473                         if (fsck_object(obj, 1, fsck_error_function))
 474                                 die("Error in object");
 475                         if (fsck_walk(obj, mark_link, NULL))
 476                                 die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
 477
 478                         if (obj->type == OBJ_TREE) {
 479                                 struct tree *item = (struct tree *) obj;
 480                                 item->buffer = NULL;
 481                         }
 482                         if (obj->type == OBJ_COMMIT) {
 483                                 struct commit *commit = (struct commit *) obj;
 484                                 commit->buffer = NULL;
 485                         }
 486                         obj->flags |= FLAG_CHECKED;
 487                 }
 488         }
 489 }
 490
 491 static void *get_base_data(struct base_data *c)
 492 {
 493         if (!c->data) {
 494                 struct object_entry *obj = c->obj;
 495
 496                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 497                         void *base = get_base_data(c->base);
 498                         void *raw = get_data_from_pack(obj);
 499                         c->data = patch_delta(
 500                                 base, c->base->size,
 501                                 raw, obj->size,
 502                                 &c->size);
 503                         free(raw);
 504                         if (!c->data)
 505                                 bad_object(obj->idx.offset, "failed to apply delta");
 506                 } else {
 507                         c->data = get_data_from_pack(obj);
 508                         c->size = obj->size;
 509                 }
 510
 511                 base_cache_used += c->size;
 512                 prune_base_data(c);
 513         }
 514         return c->data;
 515 }
 516
 517 static void resolve_delta(struct object_entry *delta_obj,
 518                           struct base_data *base, struct base_data *result)
 519 {
 520         void *base_data, *delta_data;
 521
 522         delta_obj->real_type = base->obj->real_type;
 523         delta_data = get_data_from_pack(delta_obj);
 524         base_data = get_base_data(base);
 525         result->obj = delta_obj;
 526         result->data = patch_delta(base_data, base->size,
 527                                    delta_data, delta_obj->size, &result->size);
 528         free(delta_data);
 529         if (!result->data)
 530                 bad_object(delta_obj->idx.offset, "failed to apply delta");
 531         sha1_object(result->data, result->size, delta_obj->real_type,
 532                     delta_obj->idx.sha1);
 533         nr_resolved_deltas++;
 534 }
 535
 536 static void find_unresolved_deltas(struct base_data *base,
 537                                    struct base_data *prev_base)
 538 {
 539         int i, ref_first, ref_last, ofs_first, ofs_last;
 540
 541         /*
 542          * This is a recursive function. Those brackets should help reducing
 543          * stack usage by limiting the scope of the delta_base union.
 544          */
 545         {
 546                 union delta_base base_spec;
 547
 548                 hashcpy(base_spec.sha1, base->obj->idx.sha1);
 549                 find_delta_children(&base_spec, &ref_first, &ref_last);
 550
 551                 memset(&base_spec, 0, sizeof(base_spec));
 552                 base_spec.offset = base->obj->idx.offset;
 553                 find_delta_children(&base_spec, &ofs_first, &ofs_last);
 554         }
 555
 556         if (ref_last == -1 && ofs_last == -1) {
 557                 free(base->data);
 558                 return;
 559         }
 560
 561         link_base_data(prev_base, base);
 562
 563         for (i = ref_first; i <= ref_last; i++) {
 564                 struct object_entry *child = objects + deltas[i].obj_no;
 565                 if (child->real_type == OBJ_REF_DELTA) {
 566                         struct base_data result;
 567                         resolve_delta(child, base, &result);
 568                         if (i == ref_last && ofs_last == -1)
 569                                 free_base_data(base);
 570                         find_unresolved_deltas(&result, base);
 571                 }
 572         }
 573
 574         for (i = ofs_first; i <= ofs_last; i++) {
 575                 struct object_entry *child = objects + deltas[i].obj_no;
 576                 if (child->real_type == OBJ_OFS_DELTA) {
 577                         struct base_data result;
 578                         resolve_delta(child, base, &result);
 579                         if (i == ofs_last)
 580                                 free_base_data(base);
 581                         find_unresolved_deltas(&result, base);
 582                 }
 583         }
 584
 585         unlink_base_data(base);
 586 }
 587
 588 static int compare_delta_entry(const void *a, const void *b)
 589 {
 590         const struct delta_entry *delta_a = a;
 591         const struct delta_entry *delta_b = b;
 592         return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
 593 }
 594
 595 /* Parse all objects and return the pack content SHA1 hash */
 596 static void parse_pack_objects(unsigned char *sha1)
 597 {
 598         int i;
 599         struct delta_entry *delta = deltas;
 600         struct stat st;
 601
 602         /*
 603          * First pass:
 604          * - find locations of all objects;
 605          * - calculate SHA1 of all non-delta objects;
 606          * - remember base (SHA1 or offset) for all deltas.
 607          */
 608         if (verbose)
 609                 progress = start_progress(
 610                                 from_stdin ? "Receiving objects" : "Indexing objects",
 611                                 nr_objects);
 612         for (i = 0; i < nr_objects; i++) {
 613                 struct object_entry *obj = &objects[i];
 614                 void *data = unpack_raw_entry(obj, &delta->base);
 615                 obj->real_type = obj->type;
 616                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 617                         nr_deltas++;
 618                         delta->obj_no = i;
 619                         delta++;
 620                 } else
 621                         sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 622                 free(data);
 623                 display_progress(progress, i+1);
 624         }
 625         objects[i].idx.offset = consumed_bytes;
 626         stop_progress(&progress);
 627
 628         /* Check pack integrity */
 629         flush();
 630         git_SHA1_Final(sha1, &input_ctx);
 631         if (hashcmp(fill(20), sha1))
 632                 die("pack is corrupted (SHA1 mismatch)");
 633         use(20);
 634
 635         /* If input_fd is a file, we should have reached its end now. */
 636         if (fstat(input_fd, &st))
 637                 die_errno("cannot fstat packfile");
 638         if (S_ISREG(st.st_mode) &&
 639                         lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 640                 die("pack has junk at the end");
 641
 642         if (!nr_deltas)
 643                 return;
 644
 645         /* Sort deltas by base SHA1/offset for fast searching */
 646         qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 647               compare_delta_entry);
 648
 649         /*
 650          * Second pass:
 651          * - for all non-delta objects, look if it is used as a base for
 652          *   deltas;
 653          * - if used as a base, uncompress the object and apply all deltas,
 654          *   recursively checking if the resulting object is used as a base
 655          *   for some more deltas.
 656          */
 657         if (verbose)
 658                 progress = start_progress("Resolving deltas", nr_deltas);
 659         for (i = 0; i < nr_objects; i++) {
 660                 struct object_entry *obj = &objects[i];
 661                 struct base_data base_obj;
 662
 663                 if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
 664                         continue;
 665                 base_obj.obj = obj;
 666                 base_obj.data = NULL;
 667                 find_unresolved_deltas(&base_obj, NULL);
 668                 display_progress(progress, nr_resolved_deltas);
 669         }
 670 }
 671
 672 static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 673 {
 674         z_stream stream;
 675         unsigned long maxsize;
 676         void *out;
 677
 678         memset(&stream, 0, sizeof(stream));
 679         deflateInit(&stream, zlib_compression_level);
 680         maxsize = deflateBound(&stream, size);
 681         out = xmalloc(maxsize);
 682
 683         /* Compress it */
 684         stream.next_in = in;
 685         stream.avail_in = size;
 686         stream.next_out = out;
 687         stream.avail_out = maxsize;
 688         while (deflate(&stream, Z_FINISH) == Z_OK);
 689         deflateEnd(&stream);
 690
 691         size = stream.total_out;
 692         sha1write(f, out, size);
 693         free(out);
 694         return size;
 695 }
 696
 697 static struct object_entry *append_obj_to_pack(struct sha1file *f,
 698                                const unsigned char *sha1, void *buf,
 699                                unsigned long size, enum object_type type)
 700 {
 701         struct object_entry *obj = &objects[nr_objects++];
 702         unsigned char header[10];
 703         unsigned long s = size;
 704         int n = 0;
 705         unsigned char c = (type << 4) | (s & 15);
 706         s >>= 4;
 707         while (s) {
 708                 header[n++] = c | 0x80;
 709                 c = s & 0x7f;
 710                 s >>= 7;
 711         }
 712         header[n++] = c;
 713         crc32_begin(f);
 714         sha1write(f, header, n);
 715         obj[0].size = size;
 716         obj[0].hdr_size = n;
 717         obj[0].type = type;
 718         obj[0].real_type = type;
 719         obj[1].idx.offset = obj[0].idx.offset + n;
 720         obj[1].idx.offset += write_compressed(f, buf, size);
 721         obj[0].idx.crc32 = crc32_end(f);
 722         sha1flush(f);
 723         hashcpy(obj->idx.sha1, sha1);
 724         return obj;
 725 }
 726
 727 static int delta_pos_compare(const void *_a, const void *_b)
 728 {
 729         struct delta_entry *a = *(struct delta_entry **)_a;
 730         struct delta_entry *b = *(struct delta_entry **)_b;
 731         return a->obj_no - b->obj_no;
 732 }
 733
 734 static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
 735 {
 736         struct delta_entry **sorted_by_pos;
 737         int i, n = 0;
 738
 739         /*
 740          * Since many unresolved deltas may well be themselves base objects
 741          * for more unresolved deltas, we really want to include the
 742          * smallest number of base objects that would cover as much delta
 743          * as possible by picking the
 744          * trunc deltas first, allowing for other deltas to resolve without
 745          * additional base objects.  Since most base objects are to be found
 746          * before deltas depending on them, a good heuristic is to start
 747          * resolving deltas in the same order as their position in the pack.
 748          */
 749         sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 750         for (i = 0; i < nr_deltas; i++) {
 751                 if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 752                         continue;
 753                 sorted_by_pos[n++] = &deltas[i];
 754         }
 755         qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 756
 757         for (i = 0; i < n; i++) {
 758                 struct delta_entry *d = sorted_by_pos[i];
 759                 enum object_type type;
 760                 struct base_data base_obj;
 761
 762                 if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 763                         continue;
 764                 base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
 765                 if (!base_obj.data)
 766                         continue;
 767
 768                 if (check_sha1_signature(d->base.sha1, base_obj.data,
 769                                 base_obj.size, typename(type)))
 770                         die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
 771                 base_obj.obj = append_obj_to_pack(f, d->base.sha1,
 772                                         base_obj.data, base_obj.size, type);
 773                 find_unresolved_deltas(&base_obj, NULL);
 774                 display_progress(progress, nr_resolved_deltas);
 775         }
 776         free(sorted_by_pos);
 777 }
 778
 779 static void final(const char *final_pack_name, const char *curr_pack_name,
 780                   const char *final_index_name, const char *curr_index_name,
 781                   const char *keep_name, const char *keep_msg,
 782                   unsigned char *sha1)
 783 {
 784         const char *report = "pack";
 785         char name[PATH_MAX];
 786         int err;
 787
 788         if (!from_stdin) {
 789                 close(input_fd);
 790         } else {
 791                 fsync_or_die(output_fd, curr_pack_name);
 792                 err = close(output_fd);
 793                 if (err)
 794                         die_errno("error while closing pack file");
 795         }
 796
 797         if (keep_msg) {
 798                 int keep_fd, keep_msg_len = strlen(keep_msg);
 799
 800                 if (!keep_name)
 801                         keep_fd = odb_pack_keep(name, sizeof(name), sha1);
 802                 else
 803                         keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 804
 805                 if (keep_fd < 0) {
 806                         if (errno != EEXIST)
 807                                 die_errno("cannot write keep file '%s'",
 808                                           keep_name);
 809                 } else {
 810                         if (keep_msg_len > 0) {
 811                                 write_or_die(keep_fd, keep_msg, keep_msg_len);
 812                                 write_or_die(keep_fd, "\n", 1);
 813                         }
 814                         if (close(keep_fd) != 0)
 815                                 die_errno("cannot close written keep file '%s'",
 816                                     keep_name);
 817                         report = "keep";
 818                 }
 819         }
 820
 821         if (final_pack_name != curr_pack_name) {
 822                 if (!final_pack_name) {
 823                         snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 824                                  get_object_directory(), sha1_to_hex(sha1));
 825                         final_pack_name = name;
 826                 }
 827                 if (move_temp_to_file(curr_pack_name, final_pack_name))
 828                         die("cannot store pack file");
 829         } else if (from_stdin)
 830                 chmod(final_pack_name, 0444);
 831
 832         if (final_index_name != curr_index_name) {
 833                 if (!final_index_name) {
 834                         snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 835                                  get_object_directory(), sha1_to_hex(sha1));
 836                         final_index_name = name;
 837                 }
 838                 if (move_temp_to_file(curr_index_name, final_index_name))
 839                         die("cannot store index file");
 840         } else
 841                 chmod(final_index_name, 0444);
 842
 843         if (!from_stdin) {
 844                 printf("%s\n", sha1_to_hex(sha1));
 845         } else {
 846                 char buf[48];
 847                 int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 848                                    report, sha1_to_hex(sha1));
 849                 write_or_die(1, buf, len);
 850
 851                 /*
 852                  * Let's just mimic git-unpack-objects here and write
 853                  * the last part of the input buffer to stdout.
 854                  */
 855                 while (input_len) {
 856                         err = xwrite(1, input_buffer + input_offset, input_len);
 857                         if (err <= 0)
 858                                 break;
 859                         input_len -= err;
 860                         input_offset += err;
 861                 }
 862         }
 863 }
 864
 865 static int git_index_pack_config(const char *k, const char *v, void *cb)
 866 {
 867         if (!strcmp(k, "pack.indexversion")) {
 868                 pack_idx_default_version = git_config_int(k, v);
 869                 if (pack_idx_default_version > 2)
 870                         die("bad pack.indexversion=%"PRIu32,
 871                                 pack_idx_default_version);
 872                 return 0;
 873         }
 874         return git_default_config(k, v, cb);
 875 }
 876
 877 int cmd_index_pack(int argc, const char **argv, const char *prefix)
 878 {
 879         int i, fix_thin_pack = 0;
 880         const char *curr_pack, *curr_index;
 881         const char *index_name = NULL, *pack_name = NULL;
 882         const char *keep_name = NULL, *keep_msg = NULL;
 883         char *index_name_buf = NULL, *keep_name_buf = NULL;
 884         struct pack_idx_entry **idx_objects;
 885         unsigned char pack_sha1[20];
 886
 887         if (argc == 2 && !strcmp(argv[1], "-h"))
 888                 usage(index_pack_usage);
 889
 890         /*
 891          * We wish to read the repository's config file if any, and
 892          * for that it is necessary to call setup_git_directory_gently().
 893          * However if the cwd was inside .git/objects/pack/ then we need
 894          * to go back there or all the pack name arguments will be wrong.
 895          * And in that case we cannot rely on any prefix returned by
 896          * setup_git_directory_gently() either.
 897          */
 898         {
 899                 char cwd[PATH_MAX+1];
 900                 int nongit;
 901
 902                 if (!getcwd(cwd, sizeof(cwd)-1))
 903                         die("Unable to get current working directory");
 904                 setup_git_directory_gently(&nongit);
 905                 git_config(git_index_pack_config, NULL);
 906                 if (chdir(cwd))
 907                         die("Cannot come back to cwd");
 908         }
 909
 910         for (i = 1; i < argc; i++) {
 911                 const char *arg = argv[i];
 912
 913                 if (*arg == '-') {
 914                         if (!strcmp(arg, "--stdin")) {
 915                                 from_stdin = 1;
 916                         } else if (!strcmp(arg, "--fix-thin")) {
 917                                 fix_thin_pack = 1;
 918                         } else if (!strcmp(arg, "--strict")) {
 919                                 strict = 1;
 920                         } else if (!strcmp(arg, "--keep")) {
 921                                 keep_msg = "";
 922                         } else if (!prefixcmp(arg, "--keep=")) {
 923                                 keep_msg = arg + 7;
 924                         } else if (!prefixcmp(arg, "--pack_header=")) {
 925                                 struct pack_header *hdr;
 926                                 char *c;
 927
 928                                 hdr = (struct pack_header *)input_buffer;
 929                                 hdr->hdr_signature = htonl(PACK_SIGNATURE);
 930                                 hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 931                                 if (*c != ',')
 932                                         die("bad %s", arg);
 933                                 hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 934                                 if (*c)
 935                                         die("bad %s", arg);
 936                                 input_len = sizeof(*hdr);
 937                         } else if (!strcmp(arg, "-v")) {
 938                                 verbose = 1;
 939                         } else if (!strcmp(arg, "-o")) {
 940                                 if (index_name || (i+1) >= argc)
 941                                         usage(index_pack_usage);
 942                                 index_name = argv[++i];
 943                         } else if (!prefixcmp(arg, "--index-version=")) {
 944                                 char *c;
 945                                 pack_idx_default_version = strtoul(arg + 16, &c, 10);
 946                                 if (pack_idx_default_version > 2)
 947                                         die("bad %s", arg);
 948                                 if (*c == ',')
 949                                         pack_idx_off32_limit = strtoul(c+1, &c, 0);
 950                                 if (*c || pack_idx_off32_limit & 0x80000000)
 951                                         die("bad %s", arg);
 952                         } else
 953                                 usage(index_pack_usage);
 954                         continue;
 955                 }
 956
 957                 if (pack_name)
 958                         usage(index_pack_usage);
 959                 pack_name = arg;
 960         }
 961
 962         if (!pack_name && !from_stdin)
 963                 usage(index_pack_usage);
 964         if (fix_thin_pack && !from_stdin)
 965                 die("--fix-thin cannot be used without --stdin");
 966         if (!index_name && pack_name) {
 967                 int len = strlen(pack_name);
 968                 if (!has_extension(pack_name, ".pack"))
 969                         die("packfile name '%s' does not end with '.pack'",
 970                             pack_name);
 971                 index_name_buf = xmalloc(len);
 972                 memcpy(index_name_buf, pack_name, len - 5);
 973                 strcpy(index_name_buf + len - 5, ".idx");
 974                 index_name = index_name_buf;
 975         }
 976         if (keep_msg && !keep_name && pack_name) {
 977                 int len = strlen(pack_name);
 978                 if (!has_extension(pack_name, ".pack"))
 979                         die("packfile name '%s' does not end with '.pack'",
 980                             pack_name);
 981                 keep_name_buf = xmalloc(len);
 982                 memcpy(keep_name_buf, pack_name, len - 5);
 983                 strcpy(keep_name_buf + len - 5, ".keep");
 984                 keep_name = keep_name_buf;
 985         }
 986
 987         curr_pack = open_pack_file(pack_name);
 988         parse_pack_header();
 989         objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
 990         deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
 991         parse_pack_objects(pack_sha1);
 992         if (nr_deltas == nr_resolved_deltas) {
 993                 stop_progress(&progress);
 994                 /* Flush remaining pack final 20-byte SHA1. */
 995                 flush();
 996         } else {
 997                 if (fix_thin_pack) {
 998                         struct sha1file *f;
 999                         unsigned char read_sha1[20], tail_sha1[20];
1000                         char msg[48];
1001                         int nr_unresolved = nr_deltas - nr_resolved_deltas;
1002                         int nr_objects_initial = nr_objects;
1003                         if (nr_unresolved <= 0)
1004                                 die("confusion beyond insanity");
1005                         objects = xrealloc(objects,
1006                                            (nr_objects + nr_unresolved + 1)
1007                                            * sizeof(*objects));
1008                         f = sha1fd(output_fd, curr_pack);
1009                         fix_unresolved_deltas(f, nr_unresolved);
1010                         sprintf(msg, "completed with %d local objects",
1011                                 nr_objects - nr_objects_initial);
1012                         stop_progress_msg(&progress, msg);
1013                         sha1close(f, tail_sha1, 0);
1014                         hashcpy(read_sha1, pack_sha1);
1015                         fixup_pack_header_footer(output_fd, pack_sha1,
1016                                                  curr_pack, nr_objects,
1017                                                  read_sha1, consumed_bytes-20);
1018                         if (hashcmp(read_sha1, tail_sha1) != 0)
1019                                 die("Unexpected tail checksum for %s "
1020                                     "(disk corruption?)", curr_pack);
1021                 }
1022                 if (nr_deltas != nr_resolved_deltas)
1023                         die("pack has %d unresolved deltas",
1024                             nr_deltas - nr_resolved_deltas);
1025         }
1026         free(deltas);
1027         if (strict)
1028                 check_objects();
1029
1030         idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1031         for (i = 0; i < nr_objects; i++)
1032                 idx_objects[i] = &objects[i].idx;
1033         curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
1034         free(idx_objects);
1035
1036         final(pack_name, curr_pack,
1037                 index_name, curr_index,
1038                 keep_name, keep_msg,
1039                 pack_sha1);
1040         free(objects);
1041         free(index_name_buf);
1042         free(keep_name_buf);
1043         if (pack_name == NULL)
1044                 free((void *) curr_pack);
1045         if (index_name == NULL)
1046                 free((void *) curr_index);
1047
1048         return 0;
1049 }