git.oblomov.eu Git - git/blob - builtin-pack-objects.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "object.h"
   4 #include "blob.h"
   5 #include "commit.h"
   6 #include "tag.h"
   7 #include "tree.h"
   8 #include "delta.h"
   9 #include "pack.h"
  10 #include "csum-file.h"
  11 #include "tree-walk.h"
  12 #include <sys/time.h>
  13 #include <signal.h>
  14
  15 static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
  16
  17 struct object_entry {
  18         unsigned char sha1[20];
  19         unsigned long size;     /* uncompressed size */
  20         unsigned long offset;   /* offset into the final pack file;
  21                                  * nonzero if already written.
  22                                  */
  23         unsigned int depth;     /* delta depth */
  24         unsigned int delta_limit;       /* base adjustment for in-pack delta */
  25         unsigned int hash;      /* name hint hash */
  26         enum object_type type;
  27         enum object_type in_pack_type;  /* could be delta */
  28         unsigned long delta_size;       /* delta data size (uncompressed) */
  29         struct object_entry *delta;     /* delta base object */
  30         struct packed_git *in_pack;     /* already in pack */
  31         unsigned int in_pack_offset;
  32         struct object_entry *delta_child; /* deltified objects who bases me */
  33         struct object_entry *delta_sibling; /* other deltified objects who
  34                                              * uses the same base as me
  35                                              */
  36         int preferred_base;     /* we do not pack this, but is encouraged to
  37                                  * be used as the base objectto delta huge
  38                                  * objects against.
  39                                  */
  40 };
  41
  42 /*
  43  * Objects we are going to pack are collected in objects array (dynamically
  44  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  45  * in the order we see -- typically rev-list --objects order that gives us
  46  * nice "minimum seek" order.
  47  *
  48  * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
  49  * elements in the objects array.  The former is used to build the pack
  50  * index (lists object names in the ascending order to help offset lookup),
  51  * and the latter is used to group similar things together by try_delta()
  52  * heuristics.
  53  */
  54
  55 static unsigned char object_list_sha1[20];
  56 static int non_empty;
  57 static int no_reuse_delta;
  58 static int local;
  59 static int incremental;
  60 static struct object_entry **sorted_by_sha, **sorted_by_type;
  61 static struct object_entry *objects;
  62 static int nr_objects, nr_alloc, nr_result;
  63 static const char *base_name;
  64 static unsigned char pack_file_sha1[20];
  65 static int progress = 1;
  66 static volatile sig_atomic_t progress_update;
  67 static int window = 10;
  68 static int pack_to_stdout;
  69
  70 /*
  71  * The object names in objects array are hashed with this hashtable,
  72  * to help looking up the entry by object name.  Binary search from
  73  * sorted_by_sha is also possible but this was easier to code and faster.
  74  * This hashtable is built after all the objects are seen.
  75  */
  76 static int *object_ix;
  77 static int object_ix_hashsz;
  78
  79 /*
  80  * Pack index for existing packs give us easy access to the offsets into
  81  * corresponding pack file where each object's data starts, but the entries
  82  * do not store the size of the compressed representation (uncompressed
  83  * size is easily available by examining the pack entry header).  We build
  84  * a hashtable of existing packs (pack_revindex), and keep reverse index
  85  * here -- pack index file is sorted by object name mapping to offset; this
  86  * pack_revindex[].revindex array is an ordered list of offsets, so if you
  87  * know the offset of an object, next offset is where its packed
  88  * representation ends.
  89  */
  90 struct pack_revindex {
  91         struct packed_git *p;
  92         unsigned long *revindex;
  93 } *pack_revindex = NULL;
  94 static int pack_revindex_hashsz;
  95
  96 /*
  97  * stats
  98  */
  99 static int written;
 100 static int written_delta;
 101 static int reused;
 102 static int reused_delta;
 103
 104 static int pack_revindex_ix(struct packed_git *p)
 105 {
 106         unsigned long ui = (unsigned long)p;
 107         int i;
 108
 109         ui = ui ^ (ui >> 16); /* defeat structure alignment */
 110         i = (int)(ui % pack_revindex_hashsz);
 111         while (pack_revindex[i].p) {
 112                 if (pack_revindex[i].p == p)
 113                         return i;
 114                 if (++i == pack_revindex_hashsz)
 115                         i = 0;
 116         }
 117         return -1 - i;
 118 }
 119
 120 static void prepare_pack_ix(void)
 121 {
 122         int num;
 123         struct packed_git *p;
 124         for (num = 0, p = packed_git; p; p = p->next)
 125                 num++;
 126         if (!num)
 127                 return;
 128         pack_revindex_hashsz = num * 11;
 129         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 130         for (p = packed_git; p; p = p->next) {
 131                 num = pack_revindex_ix(p);
 132                 num = - 1 - num;
 133                 pack_revindex[num].p = p;
 134         }
 135         /* revindex elements are lazily initialized */
 136 }
 137
 138 static int cmp_offset(const void *a_, const void *b_)
 139 {
 140         unsigned long a = *(unsigned long *) a_;
 141         unsigned long b = *(unsigned long *) b_;
 142         if (a < b)
 143                 return -1;
 144         else if (a == b)
 145                 return 0;
 146         else
 147                 return 1;
 148 }
 149
 150 /*
 151  * Ordered list of offsets of objects in the pack.
 152  */
 153 static void prepare_pack_revindex(struct pack_revindex *rix)
 154 {
 155         struct packed_git *p = rix->p;
 156         int num_ent = num_packed_objects(p);
 157         int i;
 158         void *index = p->index_base + 256;
 159
 160         rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1));
 161         for (i = 0; i < num_ent; i++) {
 162                 unsigned int hl = *((unsigned int *)((char *) index + 24*i));
 163                 rix->revindex[i] = ntohl(hl);
 164         }
 165         /* This knows the pack format -- the 20-byte trailer
 166          * follows immediately after the last object data.
 167          */
 168         rix->revindex[num_ent] = p->pack_size - 20;
 169         qsort(rix->revindex, num_ent, sizeof(unsigned long), cmp_offset);
 170 }
 171
 172 static unsigned long find_packed_object_size(struct packed_git *p,
 173                                              unsigned long ofs)
 174 {
 175         int num;
 176         int lo, hi;
 177         struct pack_revindex *rix;
 178         unsigned long *revindex;
 179         num = pack_revindex_ix(p);
 180         if (num < 0)
 181                 die("internal error: pack revindex uninitialized");
 182         rix = &pack_revindex[num];
 183         if (!rix->revindex)
 184                 prepare_pack_revindex(rix);
 185         revindex = rix->revindex;
 186         lo = 0;
 187         hi = num_packed_objects(p) + 1;
 188         do {
 189                 int mi = (lo + hi) / 2;
 190                 if (revindex[mi] == ofs) {
 191                         return revindex[mi+1] - ofs;
 192                 }
 193                 else if (ofs < revindex[mi])
 194                         hi = mi;
 195                 else
 196                         lo = mi + 1;
 197         } while (lo < hi);
 198         die("internal error: pack revindex corrupt");
 199 }
 200
 201 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 202 {
 203         unsigned long othersize, delta_size;
 204         char type[10];
 205         void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize);
 206         void *delta_buf;
 207
 208         if (!otherbuf)
 209                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 210         delta_buf = diff_delta(otherbuf, othersize,
 211                                buf, size, &delta_size, 0);
 212         if (!delta_buf || delta_size != entry->delta_size)
 213                 die("delta size changed");
 214         free(buf);
 215         free(otherbuf);
 216         return delta_buf;
 217 }
 218
 219 /*
 220  * The per-object header is a pretty dense thing, which is
 221  *  - first byte: low four bits are "size", then three bits of "type",
 222  *    and the high bit is "size continues".
 223  *  - each byte afterwards: low seven bits are size continuation,
 224  *    with the high bit being "size continues"
 225  */
 226 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 227 {
 228         int n = 1;
 229         unsigned char c;
 230
 231         if (type < OBJ_COMMIT || type > OBJ_DELTA)
 232                 die("bad type %d", type);
 233
 234         c = (type << 4) | (size & 15);
 235         size >>= 4;
 236         while (size) {
 237                 *hdr++ = c | 0x80;
 238                 c = size & 0x7f;
 239                 size >>= 7;
 240                 n++;
 241         }
 242         *hdr = c;
 243         return n;
 244 }
 245
 246 static int check_inflate(unsigned char *data, unsigned long len, unsigned long expect)
 247 {
 248         z_stream stream;
 249         unsigned char fakebuf[4096];
 250         int st;
 251
 252         memset(&stream, 0, sizeof(stream));
 253         stream.next_in = data;
 254         stream.avail_in = len;
 255         stream.next_out = fakebuf;
 256         stream.avail_out = sizeof(fakebuf);
 257         inflateInit(&stream);
 258
 259         while (1) {
 260                 st = inflate(&stream, Z_FINISH);
 261                 if (st == Z_STREAM_END || st == Z_OK) {
 262                         st = (stream.total_out == expect &&
 263                               stream.total_in == len) ? 0 : -1;
 264                         break;
 265                 }
 266                 if (st != Z_BUF_ERROR) {
 267                         st = -1;
 268                         break;
 269                 }
 270                 stream.next_out = fakebuf;
 271                 stream.avail_out = sizeof(fakebuf);
 272         }
 273         inflateEnd(&stream);
 274         return st;
 275 }
 276
 277 /*
 278  * we are going to reuse the existing pack entry data.  make
 279  * sure it is not corrupt.
 280  */
 281 static int revalidate_pack_entry(struct object_entry *entry, unsigned char *data, unsigned long len)
 282 {
 283         enum object_type type;
 284         unsigned long size, used;
 285
 286         if (pack_to_stdout)
 287                 return 0;
 288
 289         /* the caller has already called use_packed_git() for us,
 290          * so it is safe to access the pack data from mmapped location.
 291          * make sure the entry inflates correctly.
 292          */
 293         used = unpack_object_header_gently(data, len, &type, &size);
 294         if (!used)
 295                 return -1;
 296         if (type == OBJ_DELTA)
 297                 used += 20; /* skip base object name */
 298         data += used;
 299         len -= used;
 300         return check_inflate(data, len, entry->size);
 301 }
 302
 303 static int revalidate_loose_object(struct object_entry *entry,
 304                                    unsigned char *map,
 305                                    unsigned long mapsize)
 306 {
 307         /* we already know this is a loose object with new type header. */
 308         enum object_type type;
 309         unsigned long size, used;
 310
 311         if (pack_to_stdout)
 312                 return 0;
 313
 314         used = unpack_object_header_gently(map, mapsize, &type, &size);
 315         if (!used)
 316                 return -1;
 317         map += used;
 318         mapsize -= used;
 319         return check_inflate(map, mapsize, size);
 320 }
 321
 322 static unsigned long write_object(struct sha1file *f,
 323                                   struct object_entry *entry)
 324 {
 325         unsigned long size;
 326         char type[10];
 327         void *buf;
 328         unsigned char header[10];
 329         unsigned hdrlen, datalen;
 330         enum object_type obj_type;
 331         int to_reuse = 0;
 332
 333         if (entry->preferred_base)
 334                 return 0;
 335
 336         obj_type = entry->type;
 337         if (! entry->in_pack)
 338                 to_reuse = 0;   /* can't reuse what we don't have */
 339         else if (obj_type == OBJ_DELTA)
 340                 to_reuse = 1;   /* check_object() decided it for us */
 341         else if (obj_type != entry->in_pack_type)
 342                 to_reuse = 0;   /* pack has delta which is unusable */
 343         else if (entry->delta)
 344                 to_reuse = 0;   /* we want to pack afresh */
 345         else
 346                 to_reuse = 1;   /* we have it in-pack undeltified,
 347                                  * and we do not need to deltify it.
 348                                  */
 349
 350         if (!entry->in_pack && !entry->delta) {
 351                 unsigned char *map;
 352                 unsigned long mapsize;
 353                 map = map_sha1_file(entry->sha1, &mapsize);
 354                 if (map && !legacy_loose_object(map)) {
 355                         /* We can copy straight into the pack file */
 356                         if (revalidate_loose_object(entry, map, mapsize))
 357                                 die("corrupt loose object %s",
 358                                     sha1_to_hex(entry->sha1));
 359                         sha1write(f, map, mapsize);
 360                         munmap(map, mapsize);
 361                         written++;
 362                         reused++;
 363                         return mapsize;
 364                 }
 365                 if (map)
 366                         munmap(map, mapsize);
 367         }
 368
 369         if (!to_reuse) {
 370                 buf = read_sha1_file(entry->sha1, type, &size);
 371                 if (!buf)
 372                         die("unable to read %s", sha1_to_hex(entry->sha1));
 373                 if (size != entry->size)
 374                         die("object %s size inconsistency (%lu vs %lu)",
 375                             sha1_to_hex(entry->sha1), size, entry->size);
 376                 if (entry->delta) {
 377                         buf = delta_against(buf, size, entry);
 378                         size = entry->delta_size;
 379                         obj_type = OBJ_DELTA;
 380                 }
 381                 /*
 382                  * The object header is a byte of 'type' followed by zero or
 383                  * more bytes of length.  For deltas, the 20 bytes of delta
 384                  * sha1 follows that.
 385                  */
 386                 hdrlen = encode_header(obj_type, size, header);
 387                 sha1write(f, header, hdrlen);
 388
 389                 if (entry->delta) {
 390                         sha1write(f, entry->delta, 20);
 391                         hdrlen += 20;
 392                 }
 393                 datalen = sha1write_compressed(f, buf, size);
 394                 free(buf);
 395         }
 396         else {
 397                 struct packed_git *p = entry->in_pack;
 398                 use_packed_git(p);
 399
 400                 datalen = find_packed_object_size(p, entry->in_pack_offset);
 401                 buf = (char *) p->pack_base + entry->in_pack_offset;
 402
 403                 if (revalidate_pack_entry(entry, buf, datalen))
 404                         die("corrupt delta in pack %s", sha1_to_hex(entry->sha1));
 405                 sha1write(f, buf, datalen);
 406                 unuse_packed_git(p);
 407                 hdrlen = 0; /* not really */
 408                 if (obj_type == OBJ_DELTA)
 409                         reused_delta++;
 410                 reused++;
 411         }
 412         if (obj_type == OBJ_DELTA)
 413                 written_delta++;
 414         written++;
 415         return hdrlen + datalen;
 416 }
 417
 418 static unsigned long write_one(struct sha1file *f,
 419                                struct object_entry *e,
 420                                unsigned long offset)
 421 {
 422         if (e->offset)
 423                 /* offset starts from header size and cannot be zero
 424                  * if it is written already.
 425                  */
 426                 return offset;
 427         e->offset = offset;
 428         offset += write_object(f, e);
 429         /* if we are deltified, write out its base object. */
 430         if (e->delta)
 431                 offset = write_one(f, e->delta, offset);
 432         return offset;
 433 }
 434
 435 static void write_pack_file(void)
 436 {
 437         int i;
 438         struct sha1file *f;
 439         unsigned long offset;
 440         struct pack_header hdr;
 441         unsigned last_percent = 999;
 442         int do_progress = 0;
 443
 444         if (!base_name)
 445                 f = sha1fd(1, "<stdout>");
 446         else {
 447                 f = sha1create("%s-%s.%s", base_name,
 448                                sha1_to_hex(object_list_sha1), "pack");
 449                 do_progress = progress;
 450         }
 451         if (do_progress)
 452                 fprintf(stderr, "Writing %d objects.\n", nr_result);
 453
 454         hdr.hdr_signature = htonl(PACK_SIGNATURE);
 455         hdr.hdr_version = htonl(PACK_VERSION);
 456         hdr.hdr_entries = htonl(nr_result);
 457         sha1write(f, &hdr, sizeof(hdr));
 458         offset = sizeof(hdr);
 459         if (!nr_result)
 460                 goto done;
 461         for (i = 0; i < nr_objects; i++) {
 462                 offset = write_one(f, objects + i, offset);
 463                 if (do_progress) {
 464                         unsigned percent = written * 100 / nr_result;
 465                         if (progress_update || percent != last_percent) {
 466                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
 467                                         percent, written, nr_result);
 468                                 progress_update = 0;
 469                                 last_percent = percent;
 470                         }
 471                 }
 472         }
 473         if (do_progress)
 474                 fputc('\n', stderr);
 475  done:
 476         sha1close(f, pack_file_sha1, 1);
 477 }
 478
 479 static void write_index_file(void)
 480 {
 481         int i;
 482         struct sha1file *f = sha1create("%s-%s.%s", base_name,
 483                                         sha1_to_hex(object_list_sha1), "idx");
 484         struct object_entry **list = sorted_by_sha;
 485         struct object_entry **last = list + nr_result;
 486         unsigned int array[256];
 487
 488         /*
 489          * Write the first-level table (the list is sorted,
 490          * but we use a 256-entry lookup to be able to avoid
 491          * having to do eight extra binary search iterations).
 492          */
 493         for (i = 0; i < 256; i++) {
 494                 struct object_entry **next = list;
 495                 while (next < last) {
 496                         struct object_entry *entry = *next;
 497                         if (entry->sha1[0] != i)
 498                                 break;
 499                         next++;
 500                 }
 501                 array[i] = htonl(next - sorted_by_sha);
 502                 list = next;
 503         }
 504         sha1write(f, array, 256 * sizeof(int));
 505
 506         /*
 507          * Write the actual SHA1 entries..
 508          */
 509         list = sorted_by_sha;
 510         for (i = 0; i < nr_result; i++) {
 511                 struct object_entry *entry = *list++;
 512                 unsigned int offset = htonl(entry->offset);
 513                 sha1write(f, &offset, 4);
 514                 sha1write(f, entry->sha1, 20);
 515         }
 516         sha1write(f, pack_file_sha1, 20);
 517         sha1close(f, NULL, 1);
 518 }
 519
 520 static int locate_object_entry_hash(const unsigned char *sha1)
 521 {
 522         int i;
 523         unsigned int ui;
 524         memcpy(&ui, sha1, sizeof(unsigned int));
 525         i = ui % object_ix_hashsz;
 526         while (0 < object_ix[i]) {
 527                 if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
 528                         return i;
 529                 if (++i == object_ix_hashsz)
 530                         i = 0;
 531         }
 532         return -1 - i;
 533 }
 534
 535 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 536 {
 537         int i;
 538
 539         if (!object_ix_hashsz)
 540                 return NULL;
 541
 542         i = locate_object_entry_hash(sha1);
 543         if (0 <= i)
 544                 return &objects[object_ix[i]-1];
 545         return NULL;
 546 }
 547
 548 static void rehash_objects(void)
 549 {
 550         int i;
 551         struct object_entry *oe;
 552
 553         object_ix_hashsz = nr_objects * 3;
 554         if (object_ix_hashsz < 1024)
 555                 object_ix_hashsz = 1024;
 556         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 557         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 558         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 559                 int ix = locate_object_entry_hash(oe->sha1);
 560                 if (0 <= ix)
 561                         continue;
 562                 ix = -1 - ix;
 563                 object_ix[ix] = i + 1;
 564         }
 565 }
 566
 567 static unsigned name_hash(const char *name)
 568 {
 569         unsigned char c;
 570         unsigned hash = 0;
 571
 572         /*
 573          * This effectively just creates a sortable number from the
 574          * last sixteen non-whitespace characters. Last characters
 575          * count "most", so things that end in ".c" sort together.
 576          */
 577         while ((c = *name++) != 0) {
 578                 if (isspace(c))
 579                         continue;
 580                 hash = (hash >> 2) + (c << 24);
 581         }
 582         return hash;
 583 }
 584
 585 static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 586 {
 587         unsigned int idx = nr_objects;
 588         struct object_entry *entry;
 589         struct packed_git *p;
 590         unsigned int found_offset = 0;
 591         struct packed_git *found_pack = NULL;
 592         int ix, status = 0;
 593
 594         if (!exclude) {
 595                 for (p = packed_git; p; p = p->next) {
 596                         struct pack_entry e;
 597                         if (find_pack_entry_one(sha1, &e, p)) {
 598                                 if (incremental)
 599                                         return 0;
 600                                 if (local && !p->pack_local)
 601                                         return 0;
 602                                 if (!found_pack) {
 603                                         found_offset = e.offset;
 604                                         found_pack = e.p;
 605                                 }
 606                         }
 607                 }
 608         }
 609         if ((entry = locate_object_entry(sha1)) != NULL)
 610                 goto already_added;
 611
 612         if (idx >= nr_alloc) {
 613                 unsigned int needed = (idx + 1024) * 3 / 2;
 614                 objects = xrealloc(objects, needed * sizeof(*entry));
 615                 nr_alloc = needed;
 616         }
 617         entry = objects + idx;
 618         nr_objects = idx + 1;
 619         memset(entry, 0, sizeof(*entry));
 620         hashcpy(entry->sha1, sha1);
 621         entry->hash = hash;
 622
 623         if (object_ix_hashsz * 3 <= nr_objects * 4)
 624                 rehash_objects();
 625         else {
 626                 ix = locate_object_entry_hash(entry->sha1);
 627                 if (0 <= ix)
 628                         die("internal error in object hashing.");
 629                 object_ix[-1 - ix] = idx + 1;
 630         }
 631         status = 1;
 632
 633  already_added:
 634         if (progress_update) {
 635                 fprintf(stderr, "Counting objects...%d\r", nr_objects);
 636                 progress_update = 0;
 637         }
 638         if (exclude)
 639                 entry->preferred_base = 1;
 640         else {
 641                 if (found_pack) {
 642                         entry->in_pack = found_pack;
 643                         entry->in_pack_offset = found_offset;
 644                 }
 645         }
 646         return status;
 647 }
 648
 649 struct pbase_tree_cache {
 650         unsigned char sha1[20];
 651         int ref;
 652         int temporary;
 653         void *tree_data;
 654         unsigned long tree_size;
 655 };
 656
 657 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 658 static int pbase_tree_cache_ix(const unsigned char *sha1)
 659 {
 660         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 661 }
 662 static int pbase_tree_cache_ix_incr(int ix)
 663 {
 664         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 665 }
 666
 667 static struct pbase_tree {
 668         struct pbase_tree *next;
 669         /* This is a phony "cache" entry; we are not
 670          * going to evict it nor find it through _get()
 671          * mechanism -- this is for the toplevel node that
 672          * would almost always change with any commit.
 673          */
 674         struct pbase_tree_cache pcache;
 675 } *pbase_tree;
 676
 677 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 678 {
 679         struct pbase_tree_cache *ent, *nent;
 680         void *data;
 681         unsigned long size;
 682         char type[20];
 683         int neigh;
 684         int my_ix = pbase_tree_cache_ix(sha1);
 685         int available_ix = -1;
 686
 687         /* pbase-tree-cache acts as a limited hashtable.
 688          * your object will be found at your index or within a few
 689          * slots after that slot if it is cached.
 690          */
 691         for (neigh = 0; neigh < 8; neigh++) {
 692                 ent = pbase_tree_cache[my_ix];
 693                 if (ent && !hashcmp(ent->sha1, sha1)) {
 694                         ent->ref++;
 695                         return ent;
 696                 }
 697                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 698                          ((0 <= available_ix) &&
 699                           (!ent && pbase_tree_cache[available_ix])))
 700                         available_ix = my_ix;
 701                 if (!ent)
 702                         break;
 703                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 704         }
 705
 706         /* Did not find one.  Either we got a bogus request or
 707          * we need to read and perhaps cache.
 708          */
 709         data = read_sha1_file(sha1, type, &size);
 710         if (!data)
 711                 return NULL;
 712         if (strcmp(type, tree_type)) {
 713                 free(data);
 714                 return NULL;
 715         }
 716
 717         /* We need to either cache or return a throwaway copy */
 718
 719         if (available_ix < 0)
 720                 ent = NULL;
 721         else {
 722                 ent = pbase_tree_cache[available_ix];
 723                 my_ix = available_ix;
 724         }
 725
 726         if (!ent) {
 727                 nent = xmalloc(sizeof(*nent));
 728                 nent->temporary = (available_ix < 0);
 729         }
 730         else {
 731                 /* evict and reuse */
 732                 free(ent->tree_data);
 733                 nent = ent;
 734         }
 735         hashcpy(nent->sha1, sha1);
 736         nent->tree_data = data;
 737         nent->tree_size = size;
 738         nent->ref = 1;
 739         if (!nent->temporary)
 740                 pbase_tree_cache[my_ix] = nent;
 741         return nent;
 742 }
 743
 744 static void pbase_tree_put(struct pbase_tree_cache *cache)
 745 {
 746         if (!cache->temporary) {
 747                 cache->ref--;
 748                 return;
 749         }
 750         free(cache->tree_data);
 751         free(cache);
 752 }
 753
 754 static int name_cmp_len(const char *name)
 755 {
 756         int i;
 757         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 758                 ;
 759         return i;
 760 }
 761
 762 static void add_pbase_object(struct tree_desc *tree,
 763                              const char *name,
 764                              int cmplen,
 765                              const char *fullname)
 766 {
 767         struct name_entry entry;
 768
 769         while (tree_entry(tree,&entry)) {
 770                 unsigned long size;
 771                 char type[20];
 772
 773                 if (entry.pathlen != cmplen ||
 774                     memcmp(entry.path, name, cmplen) ||
 775                     !has_sha1_file(entry.sha1) ||
 776                     sha1_object_info(entry.sha1, type, &size))
 777                         continue;
 778                 if (name[cmplen] != '/') {
 779                         unsigned hash = name_hash(fullname);
 780                         add_object_entry(entry.sha1, hash, 1);
 781                         return;
 782                 }
 783                 if (!strcmp(type, tree_type)) {
 784                         struct tree_desc sub;
 785                         struct pbase_tree_cache *tree;
 786                         const char *down = name+cmplen+1;
 787                         int downlen = name_cmp_len(down);
 788
 789                         tree = pbase_tree_get(entry.sha1);
 790                         if (!tree)
 791                                 return;
 792                         sub.buf = tree->tree_data;
 793                         sub.size = tree->tree_size;
 794
 795                         add_pbase_object(&sub, down, downlen, fullname);
 796                         pbase_tree_put(tree);
 797                 }
 798         }
 799 }
 800
 801 static unsigned *done_pbase_paths;
 802 static int done_pbase_paths_num;
 803 static int done_pbase_paths_alloc;
 804 static int done_pbase_path_pos(unsigned hash)
 805 {
 806         int lo = 0;
 807         int hi = done_pbase_paths_num;
 808         while (lo < hi) {
 809                 int mi = (hi + lo) / 2;
 810                 if (done_pbase_paths[mi] == hash)
 811                         return mi;
 812                 if (done_pbase_paths[mi] < hash)
 813                         hi = mi;
 814                 else
 815                         lo = mi + 1;
 816         }
 817         return -lo-1;
 818 }
 819
 820 static int check_pbase_path(unsigned hash)
 821 {
 822         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 823         if (0 <= pos)
 824                 return 1;
 825         pos = -pos - 1;
 826         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 827                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 828                 done_pbase_paths = xrealloc(done_pbase_paths,
 829                                             done_pbase_paths_alloc *
 830                                             sizeof(unsigned));
 831         }
 832         done_pbase_paths_num++;
 833         if (pos < done_pbase_paths_num)
 834                 memmove(done_pbase_paths + pos + 1,
 835                         done_pbase_paths + pos,
 836                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 837         done_pbase_paths[pos] = hash;
 838         return 0;
 839 }
 840
 841 static void add_preferred_base_object(char *name, unsigned hash)
 842 {
 843         struct pbase_tree *it;
 844         int cmplen = name_cmp_len(name);
 845
 846         if (check_pbase_path(hash))
 847                 return;
 848
 849         for (it = pbase_tree; it; it = it->next) {
 850                 if (cmplen == 0) {
 851                         hash = name_hash("");
 852                         add_object_entry(it->pcache.sha1, hash, 1);
 853                 }
 854                 else {
 855                         struct tree_desc tree;
 856                         tree.buf = it->pcache.tree_data;
 857                         tree.size = it->pcache.tree_size;
 858                         add_pbase_object(&tree, name, cmplen, name);
 859                 }
 860         }
 861 }
 862
 863 static void add_preferred_base(unsigned char *sha1)
 864 {
 865         struct pbase_tree *it;
 866         void *data;
 867         unsigned long size;
 868         unsigned char tree_sha1[20];
 869
 870         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 871         if (!data)
 872                 return;
 873
 874         for (it = pbase_tree; it; it = it->next) {
 875                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
 876                         free(data);
 877                         return;
 878                 }
 879         }
 880
 881         it = xcalloc(1, sizeof(*it));
 882         it->next = pbase_tree;
 883         pbase_tree = it;
 884
 885         hashcpy(it->pcache.sha1, tree_sha1);
 886         it->pcache.tree_data = data;
 887         it->pcache.tree_size = size;
 888 }
 889
 890 static void check_object(struct object_entry *entry)
 891 {
 892         char type[20];
 893
 894         if (entry->in_pack && !entry->preferred_base) {
 895                 unsigned char base[20];
 896                 unsigned long size;
 897                 struct object_entry *base_entry;
 898
 899                 /* We want in_pack_type even if we do not reuse delta.
 900                  * There is no point not reusing non-delta representations.
 901                  */
 902                 check_reuse_pack_delta(entry->in_pack,
 903                                        entry->in_pack_offset,
 904                                        base, &size,
 905                                        &entry->in_pack_type);
 906
 907                 /* Check if it is delta, and the base is also an object
 908                  * we are going to pack.  If so we will reuse the existing
 909                  * delta.
 910                  */
 911                 if (!no_reuse_delta &&
 912                     entry->in_pack_type == OBJ_DELTA &&
 913                     (base_entry = locate_object_entry(base)) &&
 914                     (!base_entry->preferred_base)) {
 915
 916                         /* Depth value does not matter - find_deltas()
 917                          * will never consider reused delta as the
 918                          * base object to deltify other objects
 919                          * against, in order to avoid circular deltas.
 920                          */
 921
 922                         /* uncompressed size of the delta data */
 923                         entry->size = entry->delta_size = size;
 924                         entry->delta = base_entry;
 925                         entry->type = OBJ_DELTA;
 926
 927                         entry->delta_sibling = base_entry->delta_child;
 928                         base_entry->delta_child = entry;
 929
 930                         return;
 931                 }
 932                 /* Otherwise we would do the usual */
 933         }
 934
 935         if (sha1_object_info(entry->sha1, type, &entry->size))
 936                 die("unable to get type of object %s",
 937                     sha1_to_hex(entry->sha1));
 938
 939         if (!strcmp(type, commit_type)) {
 940                 entry->type = OBJ_COMMIT;
 941         } else if (!strcmp(type, tree_type)) {
 942                 entry->type = OBJ_TREE;
 943         } else if (!strcmp(type, blob_type)) {
 944                 entry->type = OBJ_BLOB;
 945         } else if (!strcmp(type, tag_type)) {
 946                 entry->type = OBJ_TAG;
 947         } else
 948                 die("unable to pack object %s of type %s",
 949                     sha1_to_hex(entry->sha1), type);
 950 }
 951
 952 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
 953 {
 954         struct object_entry *child = me->delta_child;
 955         unsigned int m = n;
 956         while (child) {
 957                 unsigned int c = check_delta_limit(child, n + 1);
 958                 if (m < c)
 959                         m = c;
 960                 child = child->delta_sibling;
 961         }
 962         return m;
 963 }
 964
 965 static void get_object_details(void)
 966 {
 967         int i;
 968         struct object_entry *entry;
 969
 970         prepare_pack_ix();
 971         for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 972                 check_object(entry);
 973
 974         if (nr_objects == nr_result) {
 975                 /*
 976                  * Depth of objects that depend on the entry -- this
 977                  * is subtracted from depth-max to break too deep
 978                  * delta chain because of delta data reusing.
 979                  * However, we loosen this restriction when we know we
 980                  * are creating a thin pack -- it will have to be
 981                  * expanded on the other end anyway, so do not
 982                  * artificially cut the delta chain and let it go as
 983                  * deep as it wants.
 984                  */
 985                 for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 986                         if (!entry->delta && entry->delta_child)
 987                                 entry->delta_limit =
 988                                         check_delta_limit(entry, 1);
 989         }
 990 }
 991
 992 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
 993
 994 static entry_sort_t current_sort;
 995
 996 static int sort_comparator(const void *_a, const void *_b)
 997 {
 998         struct object_entry *a = *(struct object_entry **)_a;
 999         struct object_entry *b = *(struct object_entry **)_b;
1000         return current_sort(a,b);
1001 }
1002
1003 static struct object_entry **create_sorted_list(entry_sort_t sort)
1004 {
1005         struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
1006         int i;
1007
1008         for (i = 0; i < nr_objects; i++)
1009                 list[i] = objects + i;
1010         current_sort = sort;
1011         qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
1012         return list;
1013 }
1014
1015 static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
1016 {
1017         return hashcmp(a->sha1, b->sha1);
1018 }
1019
1020 static struct object_entry **create_final_object_list(void)
1021 {
1022         struct object_entry **list;
1023         int i, j;
1024
1025         for (i = nr_result = 0; i < nr_objects; i++)
1026                 if (!objects[i].preferred_base)
1027                         nr_result++;
1028         list = xmalloc(nr_result * sizeof(struct object_entry *));
1029         for (i = j = 0; i < nr_objects; i++) {
1030                 if (!objects[i].preferred_base)
1031                         list[j++] = objects + i;
1032         }
1033         current_sort = sha1_sort;
1034         qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
1035         return list;
1036 }
1037
1038 static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
1039 {
1040         if (a->type < b->type)
1041                 return -1;
1042         if (a->type > b->type)
1043                 return 1;
1044         if (a->hash < b->hash)
1045                 return -1;
1046         if (a->hash > b->hash)
1047                 return 1;
1048         if (a->preferred_base < b->preferred_base)
1049                 return -1;
1050         if (a->preferred_base > b->preferred_base)
1051                 return 1;
1052         if (a->size < b->size)
1053                 return -1;
1054         if (a->size > b->size)
1055                 return 1;
1056         return a < b ? -1 : (a > b);
1057 }
1058
1059 struct unpacked {
1060         struct object_entry *entry;
1061         void *data;
1062         struct delta_index *index;
1063 };
1064
1065 /*
1066  * We search for deltas _backwards_ in a list sorted by type and
1067  * by size, so that we see progressively smaller and smaller files.
1068  * That's because we prefer deltas to be from the bigger file
1069  * to the smaller - deletes are potentially cheaper, but perhaps
1070  * more importantly, the bigger file is likely the more recent
1071  * one.
1072  */
1073 static int try_delta(struct unpacked *trg, struct unpacked *src,
1074                      unsigned max_depth)
1075 {
1076         struct object_entry *trg_entry = trg->entry;
1077         struct object_entry *src_entry = src->entry;
1078         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1079         char type[10];
1080         void *delta_buf;
1081
1082         /* Don't bother doing diffs between different types */
1083         if (trg_entry->type != src_entry->type)
1084                 return -1;
1085
1086         /* We do not compute delta to *create* objects we are not
1087          * going to pack.
1088          */
1089         if (trg_entry->preferred_base)
1090                 return -1;
1091
1092         /*
1093          * We do not bother to try a delta that we discarded
1094          * on an earlier try, but only when reusing delta data.
1095          */
1096         if (!no_reuse_delta && trg_entry->in_pack &&
1097             trg_entry->in_pack == src_entry->in_pack)
1098                 return 0;
1099
1100         /*
1101          * If the current object is at pack edge, take the depth the
1102          * objects that depend on the current object into account --
1103          * otherwise they would become too deep.
1104          */
1105         if (trg_entry->delta_child) {
1106                 if (max_depth <= trg_entry->delta_limit)
1107                         return 0;
1108                 max_depth -= trg_entry->delta_limit;
1109         }
1110         if (src_entry->depth >= max_depth)
1111                 return 0;
1112
1113         /* Now some size filtering heuristics. */
1114         trg_size = trg_entry->size;
1115         max_size = trg_size/2 - 20;
1116         max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1117         if (max_size == 0)
1118                 return 0;
1119         if (trg_entry->delta && trg_entry->delta_size <= max_size)
1120                 max_size = trg_entry->delta_size-1;
1121         src_size = src_entry->size;
1122         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1123         if (sizediff >= max_size)
1124                 return 0;
1125
1126         /* Load data if not already done */
1127         if (!trg->data) {
1128                 trg->data = read_sha1_file(trg_entry->sha1, type, &sz);
1129                 if (sz != trg_size)
1130                         die("object %s inconsistent object length (%lu vs %lu)",
1131                             sha1_to_hex(trg_entry->sha1), sz, trg_size);
1132         }
1133         if (!src->data) {
1134                 src->data = read_sha1_file(src_entry->sha1, type, &sz);
1135                 if (sz != src_size)
1136                         die("object %s inconsistent object length (%lu vs %lu)",
1137                             sha1_to_hex(src_entry->sha1), sz, src_size);
1138         }
1139         if (!src->index) {
1140                 src->index = create_delta_index(src->data, src_size);
1141                 if (!src->index)
1142                         die("out of memory");
1143         }
1144
1145         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1146         if (!delta_buf)
1147                 return 0;
1148
1149         trg_entry->delta = src_entry;
1150         trg_entry->delta_size = delta_size;
1151         trg_entry->depth = src_entry->depth + 1;
1152         free(delta_buf);
1153         return 1;
1154 }
1155
1156 static void progress_interval(int signum)
1157 {
1158         progress_update = 1;
1159 }
1160
1161 static void find_deltas(struct object_entry **list, int window, int depth)
1162 {
1163         int i, idx;
1164         unsigned int array_size = window * sizeof(struct unpacked);
1165         struct unpacked *array = xmalloc(array_size);
1166         unsigned processed = 0;
1167         unsigned last_percent = 999;
1168
1169         memset(array, 0, array_size);
1170         i = nr_objects;
1171         idx = 0;
1172         if (progress)
1173                 fprintf(stderr, "Deltifying %d objects.\n", nr_result);
1174
1175         while (--i >= 0) {
1176                 struct object_entry *entry = list[i];
1177                 struct unpacked *n = array + idx;
1178                 int j;
1179
1180                 if (!entry->preferred_base)
1181                         processed++;
1182
1183                 if (progress) {
1184                         unsigned percent = processed * 100 / nr_result;
1185                         if (percent != last_percent || progress_update) {
1186                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
1187                                         percent, processed, nr_result);
1188                                 progress_update = 0;
1189                                 last_percent = percent;
1190                         }
1191                 }
1192
1193                 if (entry->delta)
1194                         /* This happens if we decided to reuse existing
1195                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1196                          */
1197                         continue;
1198
1199                 if (entry->size < 50)
1200                         continue;
1201                 free_delta_index(n->index);
1202                 n->index = NULL;
1203                 free(n->data);
1204                 n->data = NULL;
1205                 n->entry = entry;
1206
1207                 j = window;
1208                 while (--j > 0) {
1209                         unsigned int other_idx = idx + j;
1210                         struct unpacked *m;
1211                         if (other_idx >= window)
1212                                 other_idx -= window;
1213                         m = array + other_idx;
1214                         if (!m->entry)
1215                                 break;
1216                         if (try_delta(n, m, depth) < 0)
1217                                 break;
1218                 }
1219                 /* if we made n a delta, and if n is already at max
1220                  * depth, leaving it in the window is pointless.  we
1221                  * should evict it first.
1222                  */
1223                 if (entry->delta && depth <= entry->depth)
1224                         continue;
1225
1226                 idx++;
1227                 if (idx >= window)
1228                         idx = 0;
1229         }
1230
1231         if (progress)
1232                 fputc('\n', stderr);
1233
1234         for (i = 0; i < window; ++i) {
1235                 free_delta_index(array[i].index);
1236                 free(array[i].data);
1237         }
1238         free(array);
1239 }
1240
1241 static void prepare_pack(int window, int depth)
1242 {
1243         get_object_details();
1244         sorted_by_type = create_sorted_list(type_size_sort);
1245         if (window && depth)
1246                 find_deltas(sorted_by_type, window+1, depth);
1247 }
1248
1249 static int reuse_cached_pack(unsigned char *sha1)
1250 {
1251         static const char cache[] = "pack-cache/pack-%s.%s";
1252         char *cached_pack, *cached_idx;
1253         int ifd, ofd, ifd_ix = -1;
1254
1255         cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
1256         ifd = open(cached_pack, O_RDONLY);
1257         if (ifd < 0)
1258                 return 0;
1259
1260         if (!pack_to_stdout) {
1261                 cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
1262                 ifd_ix = open(cached_idx, O_RDONLY);
1263                 if (ifd_ix < 0) {
1264                         close(ifd);
1265                         return 0;
1266                 }
1267         }
1268
1269         if (progress)
1270                 fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
1271                         sha1_to_hex(sha1));
1272
1273         if (pack_to_stdout) {
1274                 if (copy_fd(ifd, 1))
1275                         exit(1);
1276                 close(ifd);
1277         }
1278         else {
1279                 char name[PATH_MAX];
1280                 snprintf(name, sizeof(name),
1281                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
1282                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1283                 if (ofd < 0)
1284                         die("unable to open %s (%s)", name, strerror(errno));
1285                 if (copy_fd(ifd, ofd))
1286                         exit(1);
1287                 close(ifd);
1288
1289                 snprintf(name, sizeof(name),
1290                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
1291                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1292                 if (ofd < 0)
1293                         die("unable to open %s (%s)", name, strerror(errno));
1294                 if (copy_fd(ifd_ix, ofd))
1295                         exit(1);
1296                 close(ifd_ix);
1297                 puts(sha1_to_hex(sha1));
1298         }
1299
1300         return 1;
1301 }
1302
1303 static void setup_progress_signal(void)
1304 {
1305         struct sigaction sa;
1306         struct itimerval v;
1307
1308         memset(&sa, 0, sizeof(sa));
1309         sa.sa_handler = progress_interval;
1310         sigemptyset(&sa.sa_mask);
1311         sa.sa_flags = SA_RESTART;
1312         sigaction(SIGALRM, &sa, NULL);
1313
1314         v.it_interval.tv_sec = 1;
1315         v.it_interval.tv_usec = 0;
1316         v.it_value = v.it_interval;
1317         setitimer(ITIMER_REAL, &v, NULL);
1318 }
1319
1320 static int git_pack_config(const char *k, const char *v)
1321 {
1322         if(!strcmp(k, "pack.window")) {
1323                 window = git_config_int(k, v);
1324                 return 0;
1325         }
1326         return git_default_config(k, v);
1327 }
1328
1329 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1330 {
1331         SHA_CTX ctx;
1332         char line[40 + 1 + PATH_MAX + 2];
1333         int depth = 10;
1334         struct object_entry **list;
1335         int num_preferred_base = 0;
1336         int i;
1337
1338         git_config(git_pack_config);
1339
1340         progress = isatty(2);
1341         for (i = 1; i < argc; i++) {
1342                 const char *arg = argv[i];
1343
1344                 if (*arg == '-') {
1345                         if (!strcmp("--non-empty", arg)) {
1346                                 non_empty = 1;
1347                                 continue;
1348                         }
1349                         if (!strcmp("--local", arg)) {
1350                                 local = 1;
1351                                 continue;
1352                         }
1353                         if (!strcmp("--progress", arg)) {
1354                                 progress = 1;
1355                                 continue;
1356                         }
1357                         if (!strcmp("--incremental", arg)) {
1358                                 incremental = 1;
1359                                 continue;
1360                         }
1361                         if (!strncmp("--window=", arg, 9)) {
1362                                 char *end;
1363                                 window = strtoul(arg+9, &end, 0);
1364                                 if (!arg[9] || *end)
1365                                         usage(pack_usage);
1366                                 continue;
1367                         }
1368                         if (!strncmp("--depth=", arg, 8)) {
1369                                 char *end;
1370                                 depth = strtoul(arg+8, &end, 0);
1371                                 if (!arg[8] || *end)
1372                                         usage(pack_usage);
1373                                 continue;
1374                         }
1375                         if (!strcmp("--progress", arg)) {
1376                                 progress = 1;
1377                                 continue;
1378                         }
1379                         if (!strcmp("-q", arg)) {
1380                                 progress = 0;
1381                                 continue;
1382                         }
1383                         if (!strcmp("--no-reuse-delta", arg)) {
1384                                 no_reuse_delta = 1;
1385                                 continue;
1386                         }
1387                         if (!strcmp("--stdout", arg)) {
1388                                 pack_to_stdout = 1;
1389                                 continue;
1390                         }
1391                         usage(pack_usage);
1392                 }
1393                 if (base_name)
1394                         usage(pack_usage);
1395                 base_name = arg;
1396         }
1397
1398         if (pack_to_stdout != !base_name)
1399                 usage(pack_usage);
1400
1401         prepare_packed_git();
1402
1403         if (progress) {
1404                 fprintf(stderr, "Generating pack...\n");
1405                 setup_progress_signal();
1406         }
1407
1408         for (;;) {
1409                 unsigned char sha1[20];
1410                 unsigned hash;
1411
1412                 if (!fgets(line, sizeof(line), stdin)) {
1413                         if (feof(stdin))
1414                                 break;
1415                         if (!ferror(stdin))
1416                                 die("fgets returned NULL, not EOF, not error!");
1417                         if (errno != EINTR)
1418                                 die("fgets: %s", strerror(errno));
1419                         clearerr(stdin);
1420                         continue;
1421                 }
1422
1423                 if (line[0] == '-') {
1424                         if (get_sha1_hex(line+1, sha1))
1425                                 die("expected edge sha1, got garbage:\n %s",
1426                                     line+1);
1427                         if (num_preferred_base++ < window)
1428                                 add_preferred_base(sha1);
1429                         continue;
1430                 }
1431                 if (get_sha1_hex(line, sha1))
1432                         die("expected sha1, got garbage:\n %s", line);
1433                 hash = name_hash(line+41);
1434                 add_preferred_base_object(line+41, hash);
1435                 add_object_entry(sha1, hash, 0);
1436         }
1437         if (progress)
1438                 fprintf(stderr, "Done counting %d objects.\n", nr_objects);
1439         sorted_by_sha = create_final_object_list();
1440         if (non_empty && !nr_result)
1441                 return 0;
1442
1443         SHA1_Init(&ctx);
1444         list = sorted_by_sha;
1445         for (i = 0; i < nr_result; i++) {
1446                 struct object_entry *entry = *list++;
1447                 SHA1_Update(&ctx, entry->sha1, 20);
1448         }
1449         SHA1_Final(object_list_sha1, &ctx);
1450         if (progress && (nr_objects != nr_result))
1451                 fprintf(stderr, "Result has %d objects.\n", nr_result);
1452
1453         if (reuse_cached_pack(object_list_sha1))
1454                 ;
1455         else {
1456                 if (nr_result)
1457                         prepare_pack(window, depth);
1458                 if (progress && pack_to_stdout) {
1459                         /* the other end usually displays progress itself */
1460                         struct itimerval v = {{0,},};
1461                         setitimer(ITIMER_REAL, &v, NULL);
1462                         signal(SIGALRM, SIG_IGN );
1463                         progress_update = 0;
1464                 }
1465                 write_pack_file();
1466                 if (!pack_to_stdout) {
1467                         write_index_file();
1468                         puts(sha1_to_hex(object_list_sha1));
1469                 }
1470         }
1471         if (progress)
1472                 fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
1473                         nr_result, written, written_delta, reused, reused_delta);
1474         return 0;
1475 }