pack-objects.c

   1 #include "cache.h"
   2 #include "object.h"
   3 #include "delta.h"
   4 #include "pack.h"
   5 #include "csum-file.h"
   6 #include <sys/time.h>
   7
   8 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";
   9
  10 struct object_entry {
  11         unsigned char sha1[20];
  12         unsigned long size;     /* uncompressed size */
  13         unsigned long offset;   /* offset into the final pack file (nonzero if already written) */
  14         unsigned int depth;     /* delta depth */
  15         unsigned int hash;      /* name hint hash */
  16         enum object_type type;
  17         unsigned char edge;     /* reused delta chain points at this entry. */
  18         enum object_type in_pack_type;  /* could be delta */
  19         unsigned long delta_size;       /* delta data size (uncompressed) */
  20         struct object_entry *delta;     /* delta base object */
  21         struct packed_git *in_pack;     /* already in pack */
  22         unsigned int in_pack_offset;
  23 };
  24
  25 /*
  26  * Objects we are going to pack are colected in objects array (dynamically
  27  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  28  * in the order we see -- typically rev-list --objects order that gives us
  29  * nice "minimum seek" order.
  30  *
  31  * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
  32  * elements in the objects array.  The former is used to build the pack
  33  * index (lists object names in the ascending order to help offset lookup),
  34  * and the latter is used to group similar things together by try_delta()
  35  * heuristics.
  36  */
  37
  38 static unsigned char object_list_sha1[20];
  39 static int non_empty = 0;
  40 static int no_reuse_delta = 0;
  41 static int local = 0;
  42 static int incremental = 0;
  43 static struct object_entry **sorted_by_sha, **sorted_by_type;
  44 static struct object_entry *objects = NULL;
  45 static int nr_objects = 0, nr_alloc = 0;
  46 static const char *base_name;
  47 static unsigned char pack_file_sha1[20];
  48 static int progress = 1;
  49
  50 /*
  51  * The object names in objects array are hashed with this hashtable,
  52  * to help looking up the entry by object name.  Binary search from
  53  * sorted_by_sha is also possible but this was easier to code and faster.
  54  * This hashtable is built after all the objects are seen.
  55  */
  56 static int *object_ix = NULL;
  57 static int object_ix_hashsz = 0;
  58
  59 /*
  60  * Pack index for existing packs give us easy access to the offsets into
  61  * corresponding pack file where each object's data starts, but the entries
  62  * do not store the size of the compressed representation (uncompressed
  63  * size is easily available by examining the pack entry header).  We build
  64  * a hashtable of existing packs (pack_revindex), and keep reverse index
  65  * here -- pack index file is sorted by object name mapping to offset; this
  66  * pack_revindex[].revindex array is an ordered list of offsets, so if you
  67  * know the offset of an object, next offset is where its packed
  68  * representation ends.
  69  */
  70 struct pack_revindex {
  71         struct packed_git *p;
  72         unsigned long *revindex;
  73 } *pack_revindex = NULL;
  74 static int pack_revindex_hashsz = 0;
  75
  76 /*
  77  * stats
  78  */
  79 static int written = 0;
  80 static int written_delta = 0;
  81 static int reused = 0;
  82 static int reused_delta = 0;
  83
  84 static int pack_revindex_ix(struct packed_git *p)
  85 {
  86         unsigned int ui = (unsigned int) p;
  87         int i;
  88
  89         ui = ui ^ (ui >> 16); /* defeat structure alignment */
  90         i = (int)(ui % pack_revindex_hashsz);
  91         while (pack_revindex[i].p) {
  92                 if (pack_revindex[i].p == p)
  93                         return i;
  94                 if (++i == pack_revindex_hashsz)
  95                         i = 0;
  96         }
  97         return -1 - i;
  98 }
  99
 100 static void prepare_pack_ix(void)
 101 {
 102         int num;
 103         struct packed_git *p;
 104         for (num = 0, p = packed_git; p; p = p->next)
 105                 num++;
 106         if (!num)
 107                 return;
 108         pack_revindex_hashsz = num * 11;
 109         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 110         for (p = packed_git; p; p = p->next) {
 111                 num = pack_revindex_ix(p);
 112                 num = - 1 - num;
 113                 pack_revindex[num].p = p;
 114         }
 115         /* revindex elements are lazily initialized */
 116 }
 117
 118 static int cmp_offset(const void *a_, const void *b_)
 119 {
 120         unsigned long a = *(unsigned long *) a_;
 121         unsigned long b = *(unsigned long *) b_;
 122         if (a < b)
 123                 return -1;
 124         else if (a == b)
 125                 return 0;
 126         else
 127                 return 1;
 128 }
 129
 130 /*
 131  * Ordered list of offsets of objects in the pack.
 132  */
 133 static void prepare_pack_revindex(struct pack_revindex *rix)
 134 {
 135         struct packed_git *p = rix->p;
 136         int num_ent = num_packed_objects(p);
 137         int i;
 138         void *index = p->index_base + 256;
 139
 140         rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1));
 141         for (i = 0; i < num_ent; i++) {
 142                 long hl = *((long *)(index + 24 * i));
 143                 rix->revindex[i] = ntohl(hl);
 144         }
 145         /* This knows the pack format -- the 20-byte trailer
 146          * follows immediately after the last object data.
 147          */
 148         rix->revindex[num_ent] = p->pack_size - 20;
 149         qsort(rix->revindex, num_ent, sizeof(unsigned long), cmp_offset);
 150 }
 151
 152 static unsigned long find_packed_object_size(struct packed_git *p,
 153                                              unsigned long ofs)
 154 {
 155         int num;
 156         int lo, hi;
 157         struct pack_revindex *rix;
 158         unsigned long *revindex;
 159         num = pack_revindex_ix(p);
 160         if (num < 0)
 161                 die("internal error: pack revindex uninitialized");
 162         rix = &pack_revindex[num];
 163         if (!rix->revindex)
 164                 prepare_pack_revindex(rix);
 165         revindex = rix->revindex;
 166         lo = 0;
 167         hi = num_packed_objects(p) + 1;
 168         do {
 169                 int mi = (lo + hi) / 2;
 170                 if (revindex[mi] == ofs) {
 171                         return revindex[mi+1] - ofs;
 172                 }
 173                 else if (ofs < revindex[mi])
 174                         hi = mi;
 175                 else
 176                         lo = mi + 1;
 177         } while (lo < hi);
 178         die("internal error: pack revindex corrupt");
 179 }
 180
 181 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 182 {
 183         unsigned long othersize, delta_size;
 184         char type[10];
 185         void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize);
 186         void *delta_buf;
 187
 188         if (!otherbuf)
 189                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 190         delta_buf = diff_delta(otherbuf, othersize,
 191                                buf, size, &delta_size, 0);
 192         if (!delta_buf || delta_size != entry->delta_size)
 193                 die("delta size changed");
 194         free(buf);
 195         free(otherbuf);
 196         return delta_buf;
 197 }
 198
 199 /*
 200  * The per-object header is a pretty dense thing, which is
 201  *  - first byte: low four bits are "size", then three bits of "type",
 202  *    and the high bit is "size continues".
 203  *  - each byte afterwards: low seven bits are size continuation,
 204  *    with the high bit being "size continues"
 205  */
 206 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 207 {
 208         int n = 1;
 209         unsigned char c;
 210
 211         if (type < OBJ_COMMIT || type > OBJ_DELTA)
 212                 die("bad type %d", type);
 213
 214         c = (type << 4) | (size & 15);
 215         size >>= 4;
 216         while (size) {
 217                 *hdr++ = c | 0x80;
 218                 c = size & 0x7f;
 219                 size >>= 7;
 220                 n++;
 221         }
 222         *hdr = c;
 223         return n;
 224 }
 225
 226 static unsigned long write_object(struct sha1file *f, struct object_entry *entry)
 227 {
 228         unsigned long size;
 229         char type[10];
 230         void *buf;
 231         unsigned char header[10];
 232         unsigned hdrlen, datalen;
 233         enum object_type obj_type;
 234         int to_reuse = 0;
 235
 236         obj_type = entry->type;
 237         if (! entry->in_pack)
 238                 to_reuse = 0;   /* can't reuse what we don't have */
 239         else if (obj_type == OBJ_DELTA)
 240                 to_reuse = 1;   /* check_object() decided it for us */
 241         else if (obj_type != entry->in_pack_type)
 242                 to_reuse = 0;   /* pack has delta which is unusable */
 243         else if (entry->delta)
 244                 to_reuse = 0;   /* we want to pack afresh */
 245         else
 246                 to_reuse = 1;   /* we have it in-pack undeltified,
 247                                  * and we do not need to deltify it.
 248                                  */
 249
 250         if (! to_reuse) {
 251                 buf = read_sha1_file(entry->sha1, type, &size);
 252                 if (!buf)
 253                         die("unable to read %s", sha1_to_hex(entry->sha1));
 254                 if (size != entry->size)
 255                         die("object %s size inconsistency (%lu vs %lu)",
 256                             sha1_to_hex(entry->sha1), size, entry->size);
 257                 if (entry->delta) {
 258                         buf = delta_against(buf, size, entry);
 259                         size = entry->delta_size;
 260                         obj_type = OBJ_DELTA;
 261                 }
 262                 /*
 263                  * The object header is a byte of 'type' followed by zero or
 264                  * more bytes of length.  For deltas, the 20 bytes of delta
 265                  * sha1 follows that.
 266                  */
 267                 hdrlen = encode_header(obj_type, size, header);
 268                 sha1write(f, header, hdrlen);
 269
 270                 if (entry->delta) {
 271                         sha1write(f, entry->delta, 20);
 272                         hdrlen += 20;
 273                 }
 274                 datalen = sha1write_compressed(f, buf, size);
 275                 free(buf);
 276         }
 277         else {
 278                 struct packed_git *p = entry->in_pack;
 279                 use_packed_git(p);
 280
 281                 datalen = find_packed_object_size(p, entry->in_pack_offset);
 282                 buf = p->pack_base + entry->in_pack_offset;
 283                 sha1write(f, buf, datalen);
 284                 unuse_packed_git(p);
 285                 hdrlen = 0; /* not really */
 286                 if (obj_type == OBJ_DELTA)
 287                         reused_delta++;
 288                 reused++;
 289         }
 290         if (obj_type == OBJ_DELTA)
 291                 written_delta++;
 292         written++;
 293         return hdrlen + datalen;
 294 }
 295
 296 static unsigned long write_one(struct sha1file *f,
 297                                struct object_entry *e,
 298                                unsigned long offset)
 299 {
 300         if (e->offset)
 301                 /* offset starts from header size and cannot be zero
 302                  * if it is written already.
 303                  */
 304                 return offset;
 305         e->offset = offset;
 306         offset += write_object(f, e);
 307         /* if we are deltified, write out its base object. */
 308         if (e->delta)
 309                 offset = write_one(f, e->delta, offset);
 310         return offset;
 311 }
 312
 313 static void write_pack_file(void)
 314 {
 315         int i;
 316         struct sha1file *f;
 317         unsigned long offset;
 318         struct pack_header hdr;
 319
 320         if (!base_name)
 321                 f = sha1fd(1, "<stdout>");
 322         else
 323                 f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "pack");
 324         hdr.hdr_signature = htonl(PACK_SIGNATURE);
 325         hdr.hdr_version = htonl(PACK_VERSION);
 326         hdr.hdr_entries = htonl(nr_objects);
 327         sha1write(f, &hdr, sizeof(hdr));
 328         offset = sizeof(hdr);
 329         for (i = 0; i < nr_objects; i++)
 330                 offset = write_one(f, objects + i, offset);
 331
 332         sha1close(f, pack_file_sha1, 1);
 333 }
 334
 335 static void write_index_file(void)
 336 {
 337         int i;
 338         struct sha1file *f = sha1create("%s-%s.%s", base_name, sha1_to_hex(object_list_sha1), "idx");
 339         struct object_entry **list = sorted_by_sha;
 340         struct object_entry **last = list + nr_objects;
 341         unsigned int array[256];
 342
 343         /*
 344          * Write the first-level table (the list is sorted,
 345          * but we use a 256-entry lookup to be able to avoid
 346          * having to do eight extra binary search iterations).
 347          */
 348         for (i = 0; i < 256; i++) {
 349                 struct object_entry **next = list;
 350                 while (next < last) {
 351                         struct object_entry *entry = *next;
 352                         if (entry->sha1[0] != i)
 353                                 break;
 354                         next++;
 355                 }
 356                 array[i] = htonl(next - sorted_by_sha);
 357                 list = next;
 358         }
 359         sha1write(f, array, 256 * sizeof(int));
 360
 361         /*
 362          * Write the actual SHA1 entries..
 363          */
 364         list = sorted_by_sha;
 365         for (i = 0; i < nr_objects; i++) {
 366                 struct object_entry *entry = *list++;
 367                 unsigned int offset = htonl(entry->offset);
 368                 sha1write(f, &offset, 4);
 369                 sha1write(f, entry->sha1, 20);
 370         }
 371         sha1write(f, pack_file_sha1, 20);
 372         sha1close(f, NULL, 1);
 373 }
 374
 375 static int add_object_entry(unsigned char *sha1, unsigned int hash)
 376 {
 377         unsigned int idx = nr_objects;
 378         struct object_entry *entry;
 379         struct packed_git *p;
 380         unsigned int found_offset = 0;
 381         struct packed_git *found_pack = NULL;
 382
 383         for (p = packed_git; p; p = p->next) {
 384                 struct pack_entry e;
 385                 if (find_pack_entry_one(sha1, &e, p)) {
 386                         if (incremental)
 387                                 return 0;
 388                         if (local && !p->pack_local)
 389                                 return 0;
 390                         if (!found_pack) {
 391                                 found_offset = e.offset;
 392                                 found_pack = e.p;
 393                         }
 394                 }
 395         }
 396
 397         if (idx >= nr_alloc) {
 398                 unsigned int needed = (idx + 1024) * 3 / 2;
 399                 objects = xrealloc(objects, needed * sizeof(*entry));
 400                 nr_alloc = needed;
 401         }
 402         entry = objects + idx;
 403         memset(entry, 0, sizeof(*entry));
 404         memcpy(entry->sha1, sha1, 20);
 405         entry->hash = hash;
 406         if (found_pack) {
 407                 entry->in_pack = found_pack;
 408                 entry->in_pack_offset = found_offset;
 409         }
 410         nr_objects = idx+1;
 411         return 1;
 412 }
 413
 414 static int locate_object_entry_hash(unsigned char *sha1)
 415 {
 416         int i;
 417         unsigned int ui;
 418         memcpy(&ui, sha1, sizeof(unsigned int));
 419         i = ui % object_ix_hashsz;
 420         while (0 < object_ix[i]) {
 421                 if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20))
 422                         return i;
 423                 if (++i == object_ix_hashsz)
 424                         i = 0;
 425         }
 426         return -1 - i;
 427 }
 428
 429 static struct object_entry *locate_object_entry(unsigned char *sha1)
 430 {
 431         int i = locate_object_entry_hash(sha1);
 432         if (0 <= i)
 433                 return &objects[object_ix[i]-1];
 434         return NULL;
 435 }
 436
 437 static void check_object(struct object_entry *entry)
 438 {
 439         char type[20];
 440
 441         if (entry->in_pack) {
 442                 unsigned char base[20];
 443                 unsigned long size;
 444                 struct object_entry *base_entry;
 445
 446                 /* We want in_pack_type even if we do not reuse delta.
 447                  * There is no point not reusing non-delta representations.
 448                  */
 449                 check_reuse_pack_delta(entry->in_pack,
 450                                        entry->in_pack_offset,
 451                                        base, &size,
 452                                        &entry->in_pack_type);
 453
 454                 /* Check if it is delta, and the base is also an object
 455                  * we are going to pack.  If so we will reuse the existing
 456                  * delta.
 457                  */
 458                 if (!no_reuse_delta &&
 459                     entry->in_pack_type == OBJ_DELTA &&
 460                     (base_entry = locate_object_entry(base))) {
 461
 462                         /* Depth value does not matter - find_deltas()
 463                          * will never consider reused delta as the
 464                          * base object to deltify other objects
 465                          * against, in order to avoid circular deltas.
 466                          */
 467
 468                         /* uncompressed size of the delta data */
 469                         entry->size = entry->delta_size = size;
 470                         entry->delta = base_entry;
 471                         entry->type = OBJ_DELTA;
 472
 473                         base_entry->edge = 1;
 474
 475                         return;
 476                 }
 477                 /* Otherwise we would do the usual */
 478         }
 479
 480         if (sha1_object_info(entry->sha1, type, &entry->size))
 481                 die("unable to get type of object %s",
 482                     sha1_to_hex(entry->sha1));
 483
 484         if (!strcmp(type, "commit")) {
 485                 entry->type = OBJ_COMMIT;
 486         } else if (!strcmp(type, "tree")) {
 487                 entry->type = OBJ_TREE;
 488         } else if (!strcmp(type, "blob")) {
 489                 entry->type = OBJ_BLOB;
 490         } else if (!strcmp(type, "tag")) {
 491                 entry->type = OBJ_TAG;
 492         } else
 493                 die("unable to pack object %s of type %s",
 494                     sha1_to_hex(entry->sha1), type);
 495 }
 496
 497 static void hash_objects(void)
 498 {
 499         int i;
 500         struct object_entry *oe;
 501
 502         object_ix_hashsz = nr_objects * 2;
 503         object_ix = xcalloc(sizeof(int), object_ix_hashsz);
 504         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 505                 int ix = locate_object_entry_hash(oe->sha1);
 506                 if (0 <= ix) {
 507                         error("the same object '%s' added twice",
 508                               sha1_to_hex(oe->sha1));
 509                         continue;
 510                 }
 511                 ix = -1 - ix;
 512                 object_ix[ix] = i + 1;
 513         }
 514 }
 515
 516 static void get_object_details(void)
 517 {
 518         int i;
 519         struct object_entry *entry = objects;
 520
 521         hash_objects();
 522         prepare_pack_ix();
 523         for (i = 0; i < nr_objects; i++)
 524                 check_object(entry++);
 525 }
 526
 527 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
 528
 529 static entry_sort_t current_sort;
 530
 531 static int sort_comparator(const void *_a, const void *_b)
 532 {
 533         struct object_entry *a = *(struct object_entry **)_a;
 534         struct object_entry *b = *(struct object_entry **)_b;
 535         return current_sort(a,b);
 536 }
 537
 538 static struct object_entry **create_sorted_list(entry_sort_t sort)
 539 {
 540         struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
 541         int i;
 542
 543         for (i = 0; i < nr_objects; i++)
 544                 list[i] = objects + i;
 545         current_sort = sort;
 546         qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
 547         return list;
 548 }
 549
 550 static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
 551 {
 552         return memcmp(a->sha1, b->sha1, 20);
 553 }
 554
 555 static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
 556 {
 557         if (a->type < b->type)
 558                 return -1;
 559         if (a->type > b->type)
 560                 return 1;
 561         if (a->hash < b->hash)
 562                 return -1;
 563         if (a->hash > b->hash)
 564                 return 1;
 565         if (a->size < b->size)
 566                 return -1;
 567         if (a->size > b->size)
 568                 return 1;
 569         return a < b ? -1 : (a > b);
 570 }
 571
 572 struct unpacked {
 573         struct object_entry *entry;
 574         void *data;
 575 };
 576
 577 /*
 578  * We search for deltas _backwards_ in a list sorted by type and
 579  * by size, so that we see progressively smaller and smaller files.
 580  * That's because we prefer deltas to be from the bigger file
 581  * to the smaller - deletes are potentially cheaper, but perhaps
 582  * more importantly, the bigger file is likely the more recent
 583  * one.
 584  */
 585 static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_depth)
 586 {
 587         struct object_entry *cur_entry = cur->entry;
 588         struct object_entry *old_entry = old->entry;
 589         unsigned long size, oldsize, delta_size, sizediff;
 590         long max_size;
 591         void *delta_buf;
 592
 593         /* Don't bother doing diffs between different types */
 594         if (cur_entry->type != old_entry->type)
 595                 return -1;
 596
 597         /* If the current object is at edge, take the depth the objects
 598          * that depend on the current object into account -- otherwise
 599          * they would become too deep.
 600          */
 601         if (cur_entry->edge)
 602                 max_depth /= 4;
 603
 604         size = cur_entry->size;
 605         if (size < 50)
 606                 return -1;
 607         oldsize = old_entry->size;
 608         sizediff = oldsize > size ? oldsize - size : size - oldsize;
 609         if (sizediff > size / 8)
 610                 return -1;
 611         if (old_entry->depth >= max_depth)
 612                 return 0;
 613
 614         /*
 615          * NOTE!
 616          *
 617          * We always delta from the bigger to the smaller, since that's
 618          * more space-efficient (deletes don't have to say _what_ they
 619          * delete).
 620          */
 621         max_size = size / 2 - 20;
 622         if (cur_entry->delta)
 623                 max_size = cur_entry->delta_size-1;
 624         if (sizediff >= max_size)
 625                 return -1;
 626         delta_buf = diff_delta(old->data, oldsize,
 627                                cur->data, size, &delta_size, max_size);
 628         if (!delta_buf)
 629                 return 0;
 630         cur_entry->delta = old_entry;
 631         cur_entry->delta_size = delta_size;
 632         cur_entry->depth = old_entry->depth + 1;
 633         free(delta_buf);
 634         return 0;
 635 }
 636
 637 static void find_deltas(struct object_entry **list, int window, int depth)
 638 {
 639         int i, idx;
 640         unsigned int array_size = window * sizeof(struct unpacked);
 641         struct unpacked *array = xmalloc(array_size);
 642         int eye_candy;
 643
 644         memset(array, 0, array_size);
 645         i = nr_objects;
 646         idx = 0;
 647         eye_candy = i - (nr_objects / 20);
 648
 649         while (--i >= 0) {
 650                 struct object_entry *entry = list[i];
 651                 struct unpacked *n = array + idx;
 652                 unsigned long size;
 653                 char type[10];
 654                 int j;
 655
 656                 if (progress && i <= eye_candy) {
 657                         eye_candy -= nr_objects / 20;
 658                         fputc('.', stderr);
 659                 }
 660
 661                 if (entry->delta)
 662                         /* This happens if we decided to reuse existing
 663                          * delta from a pack.  "!no_reuse_delta &&" is implied.
 664                          */
 665                         continue;
 666
 667                 free(n->data);
 668                 n->entry = entry;
 669                 n->data = read_sha1_file(entry->sha1, type, &size);
 670                 if (size != entry->size)
 671                         die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size);
 672
 673                 j = window;
 674                 while (--j > 0) {
 675                         unsigned int other_idx = idx + j;
 676                         struct unpacked *m;
 677                         if (other_idx >= window)
 678                                 other_idx -= window;
 679                         m = array + other_idx;
 680                         if (!m->entry)
 681                                 break;
 682                         if (try_delta(n, m, depth) < 0)
 683                                 break;
 684                 }
 685                 idx++;
 686                 if (idx >= window)
 687                         idx = 0;
 688         }
 689
 690         for (i = 0; i < window; ++i)
 691                 free(array[i].data);
 692         free(array);
 693 }
 694
 695 static void prepare_pack(int window, int depth)
 696 {
 697         if (progress)
 698                 fprintf(stderr, "Packing %d objects", nr_objects);
 699         get_object_details();
 700         if (progress)
 701                 fputc('.', stderr);
 702
 703         sorted_by_type = create_sorted_list(type_size_sort);
 704         if (window && depth)
 705                 find_deltas(sorted_by_type, window+1, depth);
 706         if (progress)
 707                 fputc('\n', stderr);
 708         write_pack_file();
 709 }
 710
 711 static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout)
 712 {
 713         static const char cache[] = "pack-cache/pack-%s.%s";
 714         char *cached_pack, *cached_idx;
 715         int ifd, ofd, ifd_ix = -1;
 716
 717         cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
 718         ifd = open(cached_pack, O_RDONLY);
 719         if (ifd < 0)
 720                 return 0;
 721
 722         if (!pack_to_stdout) {
 723                 cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
 724                 ifd_ix = open(cached_idx, O_RDONLY);
 725                 if (ifd_ix < 0) {
 726                         close(ifd);
 727                         return 0;
 728                 }
 729         }
 730
 731         if (progress)
 732                 fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
 733                         sha1_to_hex(sha1));
 734
 735         if (pack_to_stdout) {
 736                 if (copy_fd(ifd, 1))
 737                         exit(1);
 738                 close(ifd);
 739         }
 740         else {
 741                 char name[PATH_MAX];
 742                 snprintf(name, sizeof(name),
 743                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
 744                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 745                 if (ofd < 0)
 746                         die("unable to open %s (%s)", name, strerror(errno));
 747                 if (copy_fd(ifd, ofd))
 748                         exit(1);
 749                 close(ifd);
 750
 751                 snprintf(name, sizeof(name),
 752                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
 753                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
 754                 if (ofd < 0)
 755                         die("unable to open %s (%s)", name, strerror(errno));
 756                 if (copy_fd(ifd_ix, ofd))
 757                         exit(1);
 758                 close(ifd_ix);
 759                 puts(sha1_to_hex(sha1));
 760         }
 761
 762         return 1;
 763 }
 764
 765 int main(int argc, char **argv)
 766 {
 767         SHA_CTX ctx;
 768         char line[PATH_MAX + 20];
 769         int window = 10, depth = 10, pack_to_stdout = 0;
 770         struct object_entry **list;
 771         int i;
 772         struct timeval prev_tv;
 773         int eye_candy = 0;
 774         int eye_candy_incr = 500;
 775
 776
 777         setup_git_directory();
 778
 779         for (i = 1; i < argc; i++) {
 780                 const char *arg = argv[i];
 781
 782                 if (*arg == '-') {
 783                         if (!strcmp("--non-empty", arg)) {
 784                                 non_empty = 1;
 785                                 continue;
 786                         }
 787                         if (!strcmp("--local", arg)) {
 788                                 local = 1;
 789                                 continue;
 790                         }
 791                         if (!strcmp("--incremental", arg)) {
 792                                 incremental = 1;
 793                                 continue;
 794                         }
 795                         if (!strncmp("--window=", arg, 9)) {
 796                                 char *end;
 797                                 window = strtoul(arg+9, &end, 0);
 798                                 if (!arg[9] || *end)
 799                                         usage(pack_usage);
 800                                 continue;
 801                         }
 802                         if (!strncmp("--depth=", arg, 8)) {
 803                                 char *end;
 804                                 depth = strtoul(arg+8, &end, 0);
 805                                 if (!arg[8] || *end)
 806                                         usage(pack_usage);
 807                                 continue;
 808                         }
 809                         if (!strcmp("-q", arg)) {
 810                                 progress = 0;
 811                                 continue;
 812                         }
 813                         if (!strcmp("--no-reuse-delta", arg)) {
 814                                 no_reuse_delta = 1;
 815                                 continue;
 816                         }
 817                         if (!strcmp("--stdout", arg)) {
 818                                 pack_to_stdout = 1;
 819                                 continue;
 820                         }
 821                         usage(pack_usage);
 822                 }
 823                 if (base_name)
 824                         usage(pack_usage);
 825                 base_name = arg;
 826         }
 827
 828         if (pack_to_stdout != !base_name)
 829                 usage(pack_usage);
 830
 831         prepare_packed_git();
 832         if (progress) {
 833                 fprintf(stderr, "Generating pack...\n");
 834                 gettimeofday(&prev_tv, NULL);
 835         }
 836         while (fgets(line, sizeof(line), stdin) != NULL) {
 837                 unsigned int hash;
 838                 char *p;
 839                 unsigned char sha1[20];
 840
 841                 if (progress && (eye_candy <= nr_objects)) {
 842                         fprintf(stderr, "Counting objects...%d\r", nr_objects);
 843                         if (eye_candy && (50 <= eye_candy_incr)) {
 844                                 struct timeval tv;
 845                                 int time_diff;
 846                                 gettimeofday(&tv, NULL);
 847                                 time_diff = (tv.tv_sec - prev_tv.tv_sec);
 848                                 time_diff <<= 10;
 849                                 time_diff += (tv.tv_usec - prev_tv.tv_usec);
 850                                 if ((1 << 9) < time_diff)
 851                                         eye_candy_incr += 50;
 852                                 else if (50 < eye_candy_incr)
 853                                         eye_candy_incr -= 50;
 854                         }
 855                         eye_candy += eye_candy_incr;
 856                 }
 857                 if (get_sha1_hex(line, sha1))
 858                         die("expected sha1, got garbage:\n %s", line);
 859                 hash = 0;
 860                 p = line+40;
 861                 while (*p) {
 862                         unsigned char c = *p++;
 863                         if (isspace(c))
 864                                 continue;
 865                         hash = hash * 11 + c;
 866                 }
 867                 add_object_entry(sha1, hash);
 868         }
 869         if (progress)
 870                 fprintf(stderr, "Done counting %d objects.\n", nr_objects);
 871         if (non_empty && !nr_objects)
 872                 return 0;
 873
 874         sorted_by_sha = create_sorted_list(sha1_sort);
 875         SHA1_Init(&ctx);
 876         list = sorted_by_sha;
 877         for (i = 0; i < nr_objects; i++) {
 878                 struct object_entry *entry = *list++;
 879                 SHA1_Update(&ctx, entry->sha1, 20);
 880         }
 881         SHA1_Final(object_list_sha1, &ctx);
 882
 883         if (reuse_cached_pack(object_list_sha1, pack_to_stdout))
 884                 ;
 885         else {
 886                 prepare_pack(window, depth);
 887                 if (!pack_to_stdout) {
 888                         write_index_file();
 889                         puts(sha1_to_hex(object_list_sha1));
 890                 }
 891         }
 892         if (progress)
 893                 fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
 894                         nr_objects, written, written_delta, reused, reused_delta);
 895         return 0;
 896 }