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 "diff.h"
  13 #include "revision.h"
  14 #include "list-objects.h"
  15 #include <sys/time.h>
  16 #include <signal.h>
  17
  18 static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] [--revs [--unpacked | --all]*] [--stdout | base-name] <ref-list | <object-list]";
  19
  20 struct object_entry {
  21         unsigned char sha1[20];
  22         unsigned long size;     /* uncompressed size */
  23         unsigned long offset;   /* offset into the final pack file;
  24                                  * nonzero if already written.
  25                                  */
  26         unsigned int depth;     /* delta depth */
  27         unsigned int delta_limit;       /* base adjustment for in-pack delta */
  28         unsigned int hash;      /* name hint hash */
  29         enum object_type type;
  30         enum object_type in_pack_type;  /* could be delta */
  31         unsigned long delta_size;       /* delta data size (uncompressed) */
  32         struct object_entry *delta;     /* delta base object */
  33         struct packed_git *in_pack;     /* already in pack */
  34         unsigned int in_pack_offset;
  35         struct object_entry *delta_child; /* deltified objects who bases me */
  36         struct object_entry *delta_sibling; /* other deltified objects who
  37                                              * uses the same base as me
  38                                              */
  39         int preferred_base;     /* we do not pack this, but is encouraged to
  40                                  * be used as the base objectto delta huge
  41                                  * objects against.
  42                                  */
  43 };
  44
  45 /*
  46  * Objects we are going to pack are collected in objects array (dynamically
  47  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  48  * in the order we see -- typically rev-list --objects order that gives us
  49  * nice "minimum seek" order.
  50  *
  51  * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
  52  * elements in the objects array.  The former is used to build the pack
  53  * index (lists object names in the ascending order to help offset lookup),
  54  * and the latter is used to group similar things together by try_delta()
  55  * heuristics.
  56  */
  57
  58 static unsigned char object_list_sha1[20];
  59 static int non_empty;
  60 static int no_reuse_delta;
  61 static int local;
  62 static int incremental;
  63 static struct object_entry **sorted_by_sha, **sorted_by_type;
  64 static struct object_entry *objects;
  65 static int nr_objects, nr_alloc, nr_result;
  66 static const char *base_name;
  67 static unsigned char pack_file_sha1[20];
  68 static int progress = 1;
  69 static volatile sig_atomic_t progress_update;
  70 static int window = 10;
  71 static int pack_to_stdout;
  72 static int num_preferred_base;
  73
  74 /*
  75  * The object names in objects array are hashed with this hashtable,
  76  * to help looking up the entry by object name.  Binary search from
  77  * sorted_by_sha is also possible but this was easier to code and faster.
  78  * This hashtable is built after all the objects are seen.
  79  */
  80 static int *object_ix;
  81 static int object_ix_hashsz;
  82
  83 /*
  84  * Pack index for existing packs give us easy access to the offsets into
  85  * corresponding pack file where each object's data starts, but the entries
  86  * do not store the size of the compressed representation (uncompressed
  87  * size is easily available by examining the pack entry header).  We build
  88  * a hashtable of existing packs (pack_revindex), and keep reverse index
  89  * here -- pack index file is sorted by object name mapping to offset; this
  90  * pack_revindex[].revindex array is an ordered list of offsets, so if you
  91  * know the offset of an object, next offset is where its packed
  92  * representation ends.
  93  */
  94 struct pack_revindex {
  95         struct packed_git *p;
  96         unsigned long *revindex;
  97 } *pack_revindex = NULL;
  98 static int pack_revindex_hashsz;
  99
 100 /*
 101  * stats
 102  */
 103 static int written;
 104 static int written_delta;
 105 static int reused;
 106 static int reused_delta;
 107
 108 static int pack_revindex_ix(struct packed_git *p)
 109 {
 110         unsigned long ui = (unsigned long)p;
 111         int i;
 112
 113         ui = ui ^ (ui >> 16); /* defeat structure alignment */
 114         i = (int)(ui % pack_revindex_hashsz);
 115         while (pack_revindex[i].p) {
 116                 if (pack_revindex[i].p == p)
 117                         return i;
 118                 if (++i == pack_revindex_hashsz)
 119                         i = 0;
 120         }
 121         return -1 - i;
 122 }
 123
 124 static void prepare_pack_ix(void)
 125 {
 126         int num;
 127         struct packed_git *p;
 128         for (num = 0, p = packed_git; p; p = p->next)
 129                 num++;
 130         if (!num)
 131                 return;
 132         pack_revindex_hashsz = num * 11;
 133         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 134         for (p = packed_git; p; p = p->next) {
 135                 num = pack_revindex_ix(p);
 136                 num = - 1 - num;
 137                 pack_revindex[num].p = p;
 138         }
 139         /* revindex elements are lazily initialized */
 140 }
 141
 142 static int cmp_offset(const void *a_, const void *b_)
 143 {
 144         unsigned long a = *(unsigned long *) a_;
 145         unsigned long b = *(unsigned long *) b_;
 146         if (a < b)
 147                 return -1;
 148         else if (a == b)
 149                 return 0;
 150         else
 151                 return 1;
 152 }
 153
 154 /*
 155  * Ordered list of offsets of objects in the pack.
 156  */
 157 static void prepare_pack_revindex(struct pack_revindex *rix)
 158 {
 159         struct packed_git *p = rix->p;
 160         int num_ent = num_packed_objects(p);
 161         int i;
 162         void *index = p->index_base + 256;
 163
 164         rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1));
 165         for (i = 0; i < num_ent; i++) {
 166                 unsigned int hl = *((unsigned int *)((char *) index + 24*i));
 167                 rix->revindex[i] = ntohl(hl);
 168         }
 169         /* This knows the pack format -- the 20-byte trailer
 170          * follows immediately after the last object data.
 171          */
 172         rix->revindex[num_ent] = p->pack_size - 20;
 173         qsort(rix->revindex, num_ent, sizeof(unsigned long), cmp_offset);
 174 }
 175
 176 static unsigned long find_packed_object_size(struct packed_git *p,
 177                                              unsigned long ofs)
 178 {
 179         int num;
 180         int lo, hi;
 181         struct pack_revindex *rix;
 182         unsigned long *revindex;
 183         num = pack_revindex_ix(p);
 184         if (num < 0)
 185                 die("internal error: pack revindex uninitialized");
 186         rix = &pack_revindex[num];
 187         if (!rix->revindex)
 188                 prepare_pack_revindex(rix);
 189         revindex = rix->revindex;
 190         lo = 0;
 191         hi = num_packed_objects(p) + 1;
 192         do {
 193                 int mi = (lo + hi) / 2;
 194                 if (revindex[mi] == ofs) {
 195                         return revindex[mi+1] - ofs;
 196                 }
 197                 else if (ofs < revindex[mi])
 198                         hi = mi;
 199                 else
 200                         lo = mi + 1;
 201         } while (lo < hi);
 202         die("internal error: pack revindex corrupt");
 203 }
 204
 205 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 206 {
 207         unsigned long othersize, delta_size;
 208         char type[10];
 209         void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize);
 210         void *delta_buf;
 211
 212         if (!otherbuf)
 213                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 214         delta_buf = diff_delta(otherbuf, othersize,
 215                                buf, size, &delta_size, 0);
 216         if (!delta_buf || delta_size != entry->delta_size)
 217                 die("delta size changed");
 218         free(buf);
 219         free(otherbuf);
 220         return delta_buf;
 221 }
 222
 223 /*
 224  * The per-object header is a pretty dense thing, which is
 225  *  - first byte: low four bits are "size", then three bits of "type",
 226  *    and the high bit is "size continues".
 227  *  - each byte afterwards: low seven bits are size continuation,
 228  *    with the high bit being "size continues"
 229  */
 230 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 231 {
 232         int n = 1;
 233         unsigned char c;
 234
 235         if (type < OBJ_COMMIT || type > OBJ_DELTA)
 236                 die("bad type %d", type);
 237
 238         c = (type << 4) | (size & 15);
 239         size >>= 4;
 240         while (size) {
 241                 *hdr++ = c | 0x80;
 242                 c = size & 0x7f;
 243                 size >>= 7;
 244                 n++;
 245         }
 246         *hdr = c;
 247         return n;
 248 }
 249
 250 static int check_inflate(unsigned char *data, unsigned long len, unsigned long expect)
 251 {
 252         z_stream stream;
 253         unsigned char fakebuf[4096];
 254         int st;
 255
 256         memset(&stream, 0, sizeof(stream));
 257         stream.next_in = data;
 258         stream.avail_in = len;
 259         stream.next_out = fakebuf;
 260         stream.avail_out = sizeof(fakebuf);
 261         inflateInit(&stream);
 262
 263         while (1) {
 264                 st = inflate(&stream, Z_FINISH);
 265                 if (st == Z_STREAM_END || st == Z_OK) {
 266                         st = (stream.total_out == expect &&
 267                               stream.total_in == len) ? 0 : -1;
 268                         break;
 269                 }
 270                 if (st != Z_BUF_ERROR) {
 271                         st = -1;
 272                         break;
 273                 }
 274                 stream.next_out = fakebuf;
 275                 stream.avail_out = sizeof(fakebuf);
 276         }
 277         inflateEnd(&stream);
 278         return st;
 279 }
 280
 281 /*
 282  * we are going to reuse the existing pack entry data.  make
 283  * sure it is not corrupt.
 284  */
 285 static int revalidate_pack_entry(struct object_entry *entry, unsigned char *data, unsigned long len)
 286 {
 287         enum object_type type;
 288         unsigned long size, used;
 289
 290         if (pack_to_stdout)
 291                 return 0;
 292
 293         /* the caller has already called use_packed_git() for us,
 294          * so it is safe to access the pack data from mmapped location.
 295          * make sure the entry inflates correctly.
 296          */
 297         used = unpack_object_header_gently(data, len, &type, &size);
 298         if (!used)
 299                 return -1;
 300         if (type == OBJ_DELTA)
 301                 used += 20; /* skip base object name */
 302         data += used;
 303         len -= used;
 304         return check_inflate(data, len, entry->size);
 305 }
 306
 307 static int revalidate_loose_object(struct object_entry *entry,
 308                                    unsigned char *map,
 309                                    unsigned long mapsize)
 310 {
 311         /* we already know this is a loose object with new type header. */
 312         enum object_type type;
 313         unsigned long size, used;
 314
 315         if (pack_to_stdout)
 316                 return 0;
 317
 318         used = unpack_object_header_gently(map, mapsize, &type, &size);
 319         if (!used)
 320                 return -1;
 321         map += used;
 322         mapsize -= used;
 323         return check_inflate(map, mapsize, size);
 324 }
 325
 326 static unsigned long write_object(struct sha1file *f,
 327                                   struct object_entry *entry)
 328 {
 329         unsigned long size;
 330         char type[10];
 331         void *buf;
 332         unsigned char header[10];
 333         unsigned hdrlen, datalen;
 334         enum object_type obj_type;
 335         int to_reuse = 0;
 336
 337         if (entry->preferred_base)
 338                 return 0;
 339
 340         obj_type = entry->type;
 341         if (! entry->in_pack)
 342                 to_reuse = 0;   /* can't reuse what we don't have */
 343         else if (obj_type == OBJ_DELTA)
 344                 to_reuse = 1;   /* check_object() decided it for us */
 345         else if (obj_type != entry->in_pack_type)
 346                 to_reuse = 0;   /* pack has delta which is unusable */
 347         else if (entry->delta)
 348                 to_reuse = 0;   /* we want to pack afresh */
 349         else
 350                 to_reuse = 1;   /* we have it in-pack undeltified,
 351                                  * and we do not need to deltify it.
 352                                  */
 353
 354         if (!entry->in_pack && !entry->delta) {
 355                 unsigned char *map;
 356                 unsigned long mapsize;
 357                 map = map_sha1_file(entry->sha1, &mapsize);
 358                 if (map && !legacy_loose_object(map)) {
 359                         /* We can copy straight into the pack file */
 360                         if (revalidate_loose_object(entry, map, mapsize))
 361                                 die("corrupt loose object %s",
 362                                     sha1_to_hex(entry->sha1));
 363                         sha1write(f, map, mapsize);
 364                         munmap(map, mapsize);
 365                         written++;
 366                         reused++;
 367                         return mapsize;
 368                 }
 369                 if (map)
 370                         munmap(map, mapsize);
 371         }
 372
 373         if (!to_reuse) {
 374                 buf = read_sha1_file(entry->sha1, type, &size);
 375                 if (!buf)
 376                         die("unable to read %s", sha1_to_hex(entry->sha1));
 377                 if (size != entry->size)
 378                         die("object %s size inconsistency (%lu vs %lu)",
 379                             sha1_to_hex(entry->sha1), size, entry->size);
 380                 if (entry->delta) {
 381                         buf = delta_against(buf, size, entry);
 382                         size = entry->delta_size;
 383                         obj_type = OBJ_DELTA;
 384                 }
 385                 /*
 386                  * The object header is a byte of 'type' followed by zero or
 387                  * more bytes of length.  For deltas, the 20 bytes of delta
 388                  * sha1 follows that.
 389                  */
 390                 hdrlen = encode_header(obj_type, size, header);
 391                 sha1write(f, header, hdrlen);
 392
 393                 if (entry->delta) {
 394                         sha1write(f, entry->delta, 20);
 395                         hdrlen += 20;
 396                 }
 397                 datalen = sha1write_compressed(f, buf, size);
 398                 free(buf);
 399         }
 400         else {
 401                 struct packed_git *p = entry->in_pack;
 402                 use_packed_git(p);
 403
 404                 datalen = find_packed_object_size(p, entry->in_pack_offset);
 405                 buf = (char *) p->pack_base + entry->in_pack_offset;
 406
 407                 if (revalidate_pack_entry(entry, buf, datalen))
 408                         die("corrupt delta in pack %s", sha1_to_hex(entry->sha1));
 409                 sha1write(f, buf, datalen);
 410                 unuse_packed_git(p);
 411                 hdrlen = 0; /* not really */
 412                 if (obj_type == OBJ_DELTA)
 413                         reused_delta++;
 414                 reused++;
 415         }
 416         if (obj_type == OBJ_DELTA)
 417                 written_delta++;
 418         written++;
 419         return hdrlen + datalen;
 420 }
 421
 422 static unsigned long write_one(struct sha1file *f,
 423                                struct object_entry *e,
 424                                unsigned long offset)
 425 {
 426         if (e->offset)
 427                 /* offset starts from header size and cannot be zero
 428                  * if it is written already.
 429                  */
 430                 return offset;
 431         e->offset = offset;
 432         offset += write_object(f, e);
 433         /* if we are deltified, write out its base object. */
 434         if (e->delta)
 435                 offset = write_one(f, e->delta, offset);
 436         return offset;
 437 }
 438
 439 static void write_pack_file(void)
 440 {
 441         int i;
 442         struct sha1file *f;
 443         unsigned long offset;
 444         struct pack_header hdr;
 445         unsigned last_percent = 999;
 446         int do_progress = 0;
 447
 448         if (!base_name)
 449                 f = sha1fd(1, "<stdout>");
 450         else {
 451                 f = sha1create("%s-%s.%s", base_name,
 452                                sha1_to_hex(object_list_sha1), "pack");
 453                 do_progress = progress;
 454         }
 455         if (do_progress)
 456                 fprintf(stderr, "Writing %d objects.\n", nr_result);
 457
 458         hdr.hdr_signature = htonl(PACK_SIGNATURE);
 459         hdr.hdr_version = htonl(PACK_VERSION);
 460         hdr.hdr_entries = htonl(nr_result);
 461         sha1write(f, &hdr, sizeof(hdr));
 462         offset = sizeof(hdr);
 463         if (!nr_result)
 464                 goto done;
 465         for (i = 0; i < nr_objects; i++) {
 466                 offset = write_one(f, objects + i, offset);
 467                 if (do_progress) {
 468                         unsigned percent = written * 100 / nr_result;
 469                         if (progress_update || percent != last_percent) {
 470                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
 471                                         percent, written, nr_result);
 472                                 progress_update = 0;
 473                                 last_percent = percent;
 474                         }
 475                 }
 476         }
 477         if (do_progress)
 478                 fputc('\n', stderr);
 479  done:
 480         sha1close(f, pack_file_sha1, 1);
 481 }
 482
 483 static void write_index_file(void)
 484 {
 485         int i;
 486         struct sha1file *f = sha1create("%s-%s.%s", base_name,
 487                                         sha1_to_hex(object_list_sha1), "idx");
 488         struct object_entry **list = sorted_by_sha;
 489         struct object_entry **last = list + nr_result;
 490         unsigned int array[256];
 491
 492         /*
 493          * Write the first-level table (the list is sorted,
 494          * but we use a 256-entry lookup to be able to avoid
 495          * having to do eight extra binary search iterations).
 496          */
 497         for (i = 0; i < 256; i++) {
 498                 struct object_entry **next = list;
 499                 while (next < last) {
 500                         struct object_entry *entry = *next;
 501                         if (entry->sha1[0] != i)
 502                                 break;
 503                         next++;
 504                 }
 505                 array[i] = htonl(next - sorted_by_sha);
 506                 list = next;
 507         }
 508         sha1write(f, array, 256 * sizeof(int));
 509
 510         /*
 511          * Write the actual SHA1 entries..
 512          */
 513         list = sorted_by_sha;
 514         for (i = 0; i < nr_result; i++) {
 515                 struct object_entry *entry = *list++;
 516                 unsigned int offset = htonl(entry->offset);
 517                 sha1write(f, &offset, 4);
 518                 sha1write(f, entry->sha1, 20);
 519         }
 520         sha1write(f, pack_file_sha1, 20);
 521         sha1close(f, NULL, 1);
 522 }
 523
 524 static int locate_object_entry_hash(const unsigned char *sha1)
 525 {
 526         int i;
 527         unsigned int ui;
 528         memcpy(&ui, sha1, sizeof(unsigned int));
 529         i = ui % object_ix_hashsz;
 530         while (0 < object_ix[i]) {
 531                 if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
 532                         return i;
 533                 if (++i == object_ix_hashsz)
 534                         i = 0;
 535         }
 536         return -1 - i;
 537 }
 538
 539 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 540 {
 541         int i;
 542
 543         if (!object_ix_hashsz)
 544                 return NULL;
 545
 546         i = locate_object_entry_hash(sha1);
 547         if (0 <= i)
 548                 return &objects[object_ix[i]-1];
 549         return NULL;
 550 }
 551
 552 static void rehash_objects(void)
 553 {
 554         int i;
 555         struct object_entry *oe;
 556
 557         object_ix_hashsz = nr_objects * 3;
 558         if (object_ix_hashsz < 1024)
 559                 object_ix_hashsz = 1024;
 560         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 561         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 562         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 563                 int ix = locate_object_entry_hash(oe->sha1);
 564                 if (0 <= ix)
 565                         continue;
 566                 ix = -1 - ix;
 567                 object_ix[ix] = i + 1;
 568         }
 569 }
 570
 571 static unsigned name_hash(const char *name)
 572 {
 573         unsigned char c;
 574         unsigned hash = 0;
 575
 576         /*
 577          * This effectively just creates a sortable number from the
 578          * last sixteen non-whitespace characters. Last characters
 579          * count "most", so things that end in ".c" sort together.
 580          */
 581         while ((c = *name++) != 0) {
 582                 if (isspace(c))
 583                         continue;
 584                 hash = (hash >> 2) + (c << 24);
 585         }
 586         return hash;
 587 }
 588
 589 static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 590 {
 591         unsigned int idx = nr_objects;
 592         struct object_entry *entry;
 593         struct packed_git *p;
 594         unsigned int found_offset = 0;
 595         struct packed_git *found_pack = NULL;
 596         int ix, status = 0;
 597
 598         if (!exclude) {
 599                 for (p = packed_git; p; p = p->next) {
 600                         unsigned long offset = find_pack_entry_one(sha1, p);
 601                         if (offset) {
 602                                 if (incremental)
 603                                         return 0;
 604                                 if (local && !p->pack_local)
 605                                         return 0;
 606                                 if (!found_pack) {
 607                                         found_offset = offset;
 608                                         found_pack = p;
 609                                 }
 610                         }
 611                 }
 612         }
 613         if ((entry = locate_object_entry(sha1)) != NULL)
 614                 goto already_added;
 615
 616         if (idx >= nr_alloc) {
 617                 unsigned int needed = (idx + 1024) * 3 / 2;
 618                 objects = xrealloc(objects, needed * sizeof(*entry));
 619                 nr_alloc = needed;
 620         }
 621         entry = objects + idx;
 622         nr_objects = idx + 1;
 623         memset(entry, 0, sizeof(*entry));
 624         hashcpy(entry->sha1, sha1);
 625         entry->hash = hash;
 626
 627         if (object_ix_hashsz * 3 <= nr_objects * 4)
 628                 rehash_objects();
 629         else {
 630                 ix = locate_object_entry_hash(entry->sha1);
 631                 if (0 <= ix)
 632                         die("internal error in object hashing.");
 633                 object_ix[-1 - ix] = idx + 1;
 634         }
 635         status = 1;
 636
 637  already_added:
 638         if (progress_update) {
 639                 fprintf(stderr, "Counting objects...%d\r", nr_objects);
 640                 progress_update = 0;
 641         }
 642         if (exclude)
 643                 entry->preferred_base = 1;
 644         else {
 645                 if (found_pack) {
 646                         entry->in_pack = found_pack;
 647                         entry->in_pack_offset = found_offset;
 648                 }
 649         }
 650         return status;
 651 }
 652
 653 struct pbase_tree_cache {
 654         unsigned char sha1[20];
 655         int ref;
 656         int temporary;
 657         void *tree_data;
 658         unsigned long tree_size;
 659 };
 660
 661 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 662 static int pbase_tree_cache_ix(const unsigned char *sha1)
 663 {
 664         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 665 }
 666 static int pbase_tree_cache_ix_incr(int ix)
 667 {
 668         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 669 }
 670
 671 static struct pbase_tree {
 672         struct pbase_tree *next;
 673         /* This is a phony "cache" entry; we are not
 674          * going to evict it nor find it through _get()
 675          * mechanism -- this is for the toplevel node that
 676          * would almost always change with any commit.
 677          */
 678         struct pbase_tree_cache pcache;
 679 } *pbase_tree;
 680
 681 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 682 {
 683         struct pbase_tree_cache *ent, *nent;
 684         void *data;
 685         unsigned long size;
 686         char type[20];
 687         int neigh;
 688         int my_ix = pbase_tree_cache_ix(sha1);
 689         int available_ix = -1;
 690
 691         /* pbase-tree-cache acts as a limited hashtable.
 692          * your object will be found at your index or within a few
 693          * slots after that slot if it is cached.
 694          */
 695         for (neigh = 0; neigh < 8; neigh++) {
 696                 ent = pbase_tree_cache[my_ix];
 697                 if (ent && !hashcmp(ent->sha1, sha1)) {
 698                         ent->ref++;
 699                         return ent;
 700                 }
 701                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 702                          ((0 <= available_ix) &&
 703                           (!ent && pbase_tree_cache[available_ix])))
 704                         available_ix = my_ix;
 705                 if (!ent)
 706                         break;
 707                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 708         }
 709
 710         /* Did not find one.  Either we got a bogus request or
 711          * we need to read and perhaps cache.
 712          */
 713         data = read_sha1_file(sha1, type, &size);
 714         if (!data)
 715                 return NULL;
 716         if (strcmp(type, tree_type)) {
 717                 free(data);
 718                 return NULL;
 719         }
 720
 721         /* We need to either cache or return a throwaway copy */
 722
 723         if (available_ix < 0)
 724                 ent = NULL;
 725         else {
 726                 ent = pbase_tree_cache[available_ix];
 727                 my_ix = available_ix;
 728         }
 729
 730         if (!ent) {
 731                 nent = xmalloc(sizeof(*nent));
 732                 nent->temporary = (available_ix < 0);
 733         }
 734         else {
 735                 /* evict and reuse */
 736                 free(ent->tree_data);
 737                 nent = ent;
 738         }
 739         hashcpy(nent->sha1, sha1);
 740         nent->tree_data = data;
 741         nent->tree_size = size;
 742         nent->ref = 1;
 743         if (!nent->temporary)
 744                 pbase_tree_cache[my_ix] = nent;
 745         return nent;
 746 }
 747
 748 static void pbase_tree_put(struct pbase_tree_cache *cache)
 749 {
 750         if (!cache->temporary) {
 751                 cache->ref--;
 752                 return;
 753         }
 754         free(cache->tree_data);
 755         free(cache);
 756 }
 757
 758 static int name_cmp_len(const char *name)
 759 {
 760         int i;
 761         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 762                 ;
 763         return i;
 764 }
 765
 766 static void add_pbase_object(struct tree_desc *tree,
 767                              const char *name,
 768                              int cmplen,
 769                              const char *fullname)
 770 {
 771         struct name_entry entry;
 772
 773         while (tree_entry(tree,&entry)) {
 774                 unsigned long size;
 775                 char type[20];
 776
 777                 if (entry.pathlen != cmplen ||
 778                     memcmp(entry.path, name, cmplen) ||
 779                     !has_sha1_file(entry.sha1) ||
 780                     sha1_object_info(entry.sha1, type, &size))
 781                         continue;
 782                 if (name[cmplen] != '/') {
 783                         unsigned hash = name_hash(fullname);
 784                         add_object_entry(entry.sha1, hash, 1);
 785                         return;
 786                 }
 787                 if (!strcmp(type, tree_type)) {
 788                         struct tree_desc sub;
 789                         struct pbase_tree_cache *tree;
 790                         const char *down = name+cmplen+1;
 791                         int downlen = name_cmp_len(down);
 792
 793                         tree = pbase_tree_get(entry.sha1);
 794                         if (!tree)
 795                                 return;
 796                         sub.buf = tree->tree_data;
 797                         sub.size = tree->tree_size;
 798
 799                         add_pbase_object(&sub, down, downlen, fullname);
 800                         pbase_tree_put(tree);
 801                 }
 802         }
 803 }
 804
 805 static unsigned *done_pbase_paths;
 806 static int done_pbase_paths_num;
 807 static int done_pbase_paths_alloc;
 808 static int done_pbase_path_pos(unsigned hash)
 809 {
 810         int lo = 0;
 811         int hi = done_pbase_paths_num;
 812         while (lo < hi) {
 813                 int mi = (hi + lo) / 2;
 814                 if (done_pbase_paths[mi] == hash)
 815                         return mi;
 816                 if (done_pbase_paths[mi] < hash)
 817                         hi = mi;
 818                 else
 819                         lo = mi + 1;
 820         }
 821         return -lo-1;
 822 }
 823
 824 static int check_pbase_path(unsigned hash)
 825 {
 826         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 827         if (0 <= pos)
 828                 return 1;
 829         pos = -pos - 1;
 830         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 831                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 832                 done_pbase_paths = xrealloc(done_pbase_paths,
 833                                             done_pbase_paths_alloc *
 834                                             sizeof(unsigned));
 835         }
 836         done_pbase_paths_num++;
 837         if (pos < done_pbase_paths_num)
 838                 memmove(done_pbase_paths + pos + 1,
 839                         done_pbase_paths + pos,
 840                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 841         done_pbase_paths[pos] = hash;
 842         return 0;
 843 }
 844
 845 static void add_preferred_base_object(const char *name, unsigned hash)
 846 {
 847         struct pbase_tree *it;
 848         int cmplen = name_cmp_len(name);
 849
 850         if (check_pbase_path(hash))
 851                 return;
 852
 853         for (it = pbase_tree; it; it = it->next) {
 854                 if (cmplen == 0) {
 855                         hash = name_hash("");
 856                         add_object_entry(it->pcache.sha1, hash, 1);
 857                 }
 858                 else {
 859                         struct tree_desc tree;
 860                         tree.buf = it->pcache.tree_data;
 861                         tree.size = it->pcache.tree_size;
 862                         add_pbase_object(&tree, name, cmplen, name);
 863                 }
 864         }
 865 }
 866
 867 static void add_preferred_base(unsigned char *sha1)
 868 {
 869         struct pbase_tree *it;
 870         void *data;
 871         unsigned long size;
 872         unsigned char tree_sha1[20];
 873
 874         if (window <= num_preferred_base++)
 875                 return;
 876
 877         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 878         if (!data)
 879                 return;
 880
 881         for (it = pbase_tree; it; it = it->next) {
 882                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
 883                         free(data);
 884                         return;
 885                 }
 886         }
 887
 888         it = xcalloc(1, sizeof(*it));
 889         it->next = pbase_tree;
 890         pbase_tree = it;
 891
 892         hashcpy(it->pcache.sha1, tree_sha1);
 893         it->pcache.tree_data = data;
 894         it->pcache.tree_size = size;
 895 }
 896
 897 static void check_object(struct object_entry *entry)
 898 {
 899         char type[20];
 900
 901         if (entry->in_pack && !entry->preferred_base) {
 902                 unsigned char base[20];
 903                 unsigned long size;
 904                 struct object_entry *base_entry;
 905
 906                 /* We want in_pack_type even if we do not reuse delta.
 907                  * There is no point not reusing non-delta representations.
 908                  */
 909                 check_reuse_pack_delta(entry->in_pack,
 910                                        entry->in_pack_offset,
 911                                        base, &size,
 912                                        &entry->in_pack_type);
 913
 914                 /* Check if it is delta, and the base is also an object
 915                  * we are going to pack.  If so we will reuse the existing
 916                  * delta.
 917                  */
 918                 if (!no_reuse_delta &&
 919                     entry->in_pack_type == OBJ_DELTA &&
 920                     (base_entry = locate_object_entry(base)) &&
 921                     (!base_entry->preferred_base)) {
 922
 923                         /* Depth value does not matter - find_deltas()
 924                          * will never consider reused delta as the
 925                          * base object to deltify other objects
 926                          * against, in order to avoid circular deltas.
 927                          */
 928
 929                         /* uncompressed size of the delta data */
 930                         entry->size = entry->delta_size = size;
 931                         entry->delta = base_entry;
 932                         entry->type = OBJ_DELTA;
 933
 934                         entry->delta_sibling = base_entry->delta_child;
 935                         base_entry->delta_child = entry;
 936
 937                         return;
 938                 }
 939                 /* Otherwise we would do the usual */
 940         }
 941
 942         if (sha1_object_info(entry->sha1, type, &entry->size))
 943                 die("unable to get type of object %s",
 944                     sha1_to_hex(entry->sha1));
 945
 946         if (!strcmp(type, commit_type)) {
 947                 entry->type = OBJ_COMMIT;
 948         } else if (!strcmp(type, tree_type)) {
 949                 entry->type = OBJ_TREE;
 950         } else if (!strcmp(type, blob_type)) {
 951                 entry->type = OBJ_BLOB;
 952         } else if (!strcmp(type, tag_type)) {
 953                 entry->type = OBJ_TAG;
 954         } else
 955                 die("unable to pack object %s of type %s",
 956                     sha1_to_hex(entry->sha1), type);
 957 }
 958
 959 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
 960 {
 961         struct object_entry *child = me->delta_child;
 962         unsigned int m = n;
 963         while (child) {
 964                 unsigned int c = check_delta_limit(child, n + 1);
 965                 if (m < c)
 966                         m = c;
 967                 child = child->delta_sibling;
 968         }
 969         return m;
 970 }
 971
 972 static void get_object_details(void)
 973 {
 974         int i;
 975         struct object_entry *entry;
 976
 977         prepare_pack_ix();
 978         for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 979                 check_object(entry);
 980
 981         if (nr_objects == nr_result) {
 982                 /*
 983                  * Depth of objects that depend on the entry -- this
 984                  * is subtracted from depth-max to break too deep
 985                  * delta chain because of delta data reusing.
 986                  * However, we loosen this restriction when we know we
 987                  * are creating a thin pack -- it will have to be
 988                  * expanded on the other end anyway, so do not
 989                  * artificially cut the delta chain and let it go as
 990                  * deep as it wants.
 991                  */
 992                 for (i = 0, entry = objects; i < nr_objects; i++, entry++)
 993                         if (!entry->delta && entry->delta_child)
 994                                 entry->delta_limit =
 995                                         check_delta_limit(entry, 1);
 996         }
 997 }
 998
 999 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
1000
1001 static entry_sort_t current_sort;
1002
1003 static int sort_comparator(const void *_a, const void *_b)
1004 {
1005         struct object_entry *a = *(struct object_entry **)_a;
1006         struct object_entry *b = *(struct object_entry **)_b;
1007         return current_sort(a,b);
1008 }
1009
1010 static struct object_entry **create_sorted_list(entry_sort_t sort)
1011 {
1012         struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
1013         int i;
1014
1015         for (i = 0; i < nr_objects; i++)
1016                 list[i] = objects + i;
1017         current_sort = sort;
1018         qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
1019         return list;
1020 }
1021
1022 static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
1023 {
1024         return hashcmp(a->sha1, b->sha1);
1025 }
1026
1027 static struct object_entry **create_final_object_list(void)
1028 {
1029         struct object_entry **list;
1030         int i, j;
1031
1032         for (i = nr_result = 0; i < nr_objects; i++)
1033                 if (!objects[i].preferred_base)
1034                         nr_result++;
1035         list = xmalloc(nr_result * sizeof(struct object_entry *));
1036         for (i = j = 0; i < nr_objects; i++) {
1037                 if (!objects[i].preferred_base)
1038                         list[j++] = objects + i;
1039         }
1040         current_sort = sha1_sort;
1041         qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
1042         return list;
1043 }
1044
1045 static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
1046 {
1047         if (a->type < b->type)
1048                 return -1;
1049         if (a->type > b->type)
1050                 return 1;
1051         if (a->hash < b->hash)
1052                 return -1;
1053         if (a->hash > b->hash)
1054                 return 1;
1055         if (a->preferred_base < b->preferred_base)
1056                 return -1;
1057         if (a->preferred_base > b->preferred_base)
1058                 return 1;
1059         if (a->size < b->size)
1060                 return -1;
1061         if (a->size > b->size)
1062                 return 1;
1063         return a < b ? -1 : (a > b);
1064 }
1065
1066 struct unpacked {
1067         struct object_entry *entry;
1068         void *data;
1069         struct delta_index *index;
1070 };
1071
1072 /*
1073  * We search for deltas _backwards_ in a list sorted by type and
1074  * by size, so that we see progressively smaller and smaller files.
1075  * That's because we prefer deltas to be from the bigger file
1076  * to the smaller - deletes are potentially cheaper, but perhaps
1077  * more importantly, the bigger file is likely the more recent
1078  * one.
1079  */
1080 static int try_delta(struct unpacked *trg, struct unpacked *src,
1081                      unsigned max_depth)
1082 {
1083         struct object_entry *trg_entry = trg->entry;
1084         struct object_entry *src_entry = src->entry;
1085         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1086         char type[10];
1087         void *delta_buf;
1088
1089         /* Don't bother doing diffs between different types */
1090         if (trg_entry->type != src_entry->type)
1091                 return -1;
1092
1093         /* We do not compute delta to *create* objects we are not
1094          * going to pack.
1095          */
1096         if (trg_entry->preferred_base)
1097                 return -1;
1098
1099         /*
1100          * We do not bother to try a delta that we discarded
1101          * on an earlier try, but only when reusing delta data.
1102          */
1103         if (!no_reuse_delta && trg_entry->in_pack &&
1104             trg_entry->in_pack == src_entry->in_pack)
1105                 return 0;
1106
1107         /*
1108          * If the current object is at pack edge, take the depth the
1109          * objects that depend on the current object into account --
1110          * otherwise they would become too deep.
1111          */
1112         if (trg_entry->delta_child) {
1113                 if (max_depth <= trg_entry->delta_limit)
1114                         return 0;
1115                 max_depth -= trg_entry->delta_limit;
1116         }
1117         if (src_entry->depth >= max_depth)
1118                 return 0;
1119
1120         /* Now some size filtering heuristics. */
1121         trg_size = trg_entry->size;
1122         max_size = trg_size/2 - 20;
1123         max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1124         if (max_size == 0)
1125                 return 0;
1126         if (trg_entry->delta && trg_entry->delta_size <= max_size)
1127                 max_size = trg_entry->delta_size-1;
1128         src_size = src_entry->size;
1129         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1130         if (sizediff >= max_size)
1131                 return 0;
1132
1133         /* Load data if not already done */
1134         if (!trg->data) {
1135                 trg->data = read_sha1_file(trg_entry->sha1, type, &sz);
1136                 if (sz != trg_size)
1137                         die("object %s inconsistent object length (%lu vs %lu)",
1138                             sha1_to_hex(trg_entry->sha1), sz, trg_size);
1139         }
1140         if (!src->data) {
1141                 src->data = read_sha1_file(src_entry->sha1, type, &sz);
1142                 if (sz != src_size)
1143                         die("object %s inconsistent object length (%lu vs %lu)",
1144                             sha1_to_hex(src_entry->sha1), sz, src_size);
1145         }
1146         if (!src->index) {
1147                 src->index = create_delta_index(src->data, src_size);
1148                 if (!src->index)
1149                         die("out of memory");
1150         }
1151
1152         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1153         if (!delta_buf)
1154                 return 0;
1155
1156         trg_entry->delta = src_entry;
1157         trg_entry->delta_size = delta_size;
1158         trg_entry->depth = src_entry->depth + 1;
1159         free(delta_buf);
1160         return 1;
1161 }
1162
1163 static void progress_interval(int signum)
1164 {
1165         progress_update = 1;
1166 }
1167
1168 static void find_deltas(struct object_entry **list, int window, int depth)
1169 {
1170         int i, idx;
1171         unsigned int array_size = window * sizeof(struct unpacked);
1172         struct unpacked *array = xmalloc(array_size);
1173         unsigned processed = 0;
1174         unsigned last_percent = 999;
1175
1176         memset(array, 0, array_size);
1177         i = nr_objects;
1178         idx = 0;
1179         if (progress)
1180                 fprintf(stderr, "Deltifying %d objects.\n", nr_result);
1181
1182         while (--i >= 0) {
1183                 struct object_entry *entry = list[i];
1184                 struct unpacked *n = array + idx;
1185                 int j;
1186
1187                 if (!entry->preferred_base)
1188                         processed++;
1189
1190                 if (progress) {
1191                         unsigned percent = processed * 100 / nr_result;
1192                         if (percent != last_percent || progress_update) {
1193                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
1194                                         percent, processed, nr_result);
1195                                 progress_update = 0;
1196                                 last_percent = percent;
1197                         }
1198                 }
1199
1200                 if (entry->delta)
1201                         /* This happens if we decided to reuse existing
1202                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1203                          */
1204                         continue;
1205
1206                 if (entry->size < 50)
1207                         continue;
1208                 free_delta_index(n->index);
1209                 n->index = NULL;
1210                 free(n->data);
1211                 n->data = NULL;
1212                 n->entry = entry;
1213
1214                 j = window;
1215                 while (--j > 0) {
1216                         unsigned int other_idx = idx + j;
1217                         struct unpacked *m;
1218                         if (other_idx >= window)
1219                                 other_idx -= window;
1220                         m = array + other_idx;
1221                         if (!m->entry)
1222                                 break;
1223                         if (try_delta(n, m, depth) < 0)
1224                                 break;
1225                 }
1226                 /* if we made n a delta, and if n is already at max
1227                  * depth, leaving it in the window is pointless.  we
1228                  * should evict it first.
1229                  */
1230                 if (entry->delta && depth <= entry->depth)
1231                         continue;
1232
1233                 idx++;
1234                 if (idx >= window)
1235                         idx = 0;
1236         }
1237
1238         if (progress)
1239                 fputc('\n', stderr);
1240
1241         for (i = 0; i < window; ++i) {
1242                 free_delta_index(array[i].index);
1243                 free(array[i].data);
1244         }
1245         free(array);
1246 }
1247
1248 static void prepare_pack(int window, int depth)
1249 {
1250         get_object_details();
1251         sorted_by_type = create_sorted_list(type_size_sort);
1252         if (window && depth)
1253                 find_deltas(sorted_by_type, window+1, depth);
1254 }
1255
1256 static int reuse_cached_pack(unsigned char *sha1)
1257 {
1258         static const char cache[] = "pack-cache/pack-%s.%s";
1259         char *cached_pack, *cached_idx;
1260         int ifd, ofd, ifd_ix = -1;
1261
1262         cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
1263         ifd = open(cached_pack, O_RDONLY);
1264         if (ifd < 0)
1265                 return 0;
1266
1267         if (!pack_to_stdout) {
1268                 cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
1269                 ifd_ix = open(cached_idx, O_RDONLY);
1270                 if (ifd_ix < 0) {
1271                         close(ifd);
1272                         return 0;
1273                 }
1274         }
1275
1276         if (progress)
1277                 fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects,
1278                         sha1_to_hex(sha1));
1279
1280         if (pack_to_stdout) {
1281                 if (copy_fd(ifd, 1))
1282                         exit(1);
1283                 close(ifd);
1284         }
1285         else {
1286                 char name[PATH_MAX];
1287                 snprintf(name, sizeof(name),
1288                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
1289                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1290                 if (ofd < 0)
1291                         die("unable to open %s (%s)", name, strerror(errno));
1292                 if (copy_fd(ifd, ofd))
1293                         exit(1);
1294                 close(ifd);
1295
1296                 snprintf(name, sizeof(name),
1297                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
1298                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1299                 if (ofd < 0)
1300                         die("unable to open %s (%s)", name, strerror(errno));
1301                 if (copy_fd(ifd_ix, ofd))
1302                         exit(1);
1303                 close(ifd_ix);
1304                 puts(sha1_to_hex(sha1));
1305         }
1306
1307         return 1;
1308 }
1309
1310 static void setup_progress_signal(void)
1311 {
1312         struct sigaction sa;
1313         struct itimerval v;
1314
1315         memset(&sa, 0, sizeof(sa));
1316         sa.sa_handler = progress_interval;
1317         sigemptyset(&sa.sa_mask);
1318         sa.sa_flags = SA_RESTART;
1319         sigaction(SIGALRM, &sa, NULL);
1320
1321         v.it_interval.tv_sec = 1;
1322         v.it_interval.tv_usec = 0;
1323         v.it_value = v.it_interval;
1324         setitimer(ITIMER_REAL, &v, NULL);
1325 }
1326
1327 static int git_pack_config(const char *k, const char *v)
1328 {
1329         if(!strcmp(k, "pack.window")) {
1330                 window = git_config_int(k, v);
1331                 return 0;
1332         }
1333         return git_default_config(k, v);
1334 }
1335
1336 static void read_object_list_from_stdin(void)
1337 {
1338         char line[40 + 1 + PATH_MAX + 2];
1339         unsigned char sha1[20];
1340         unsigned hash;
1341
1342         for (;;) {
1343                 if (!fgets(line, sizeof(line), stdin)) {
1344                         if (feof(stdin))
1345                                 break;
1346                         if (!ferror(stdin))
1347                                 die("fgets returned NULL, not EOF, not error!");
1348                         if (errno != EINTR)
1349                                 die("fgets: %s", strerror(errno));
1350                         clearerr(stdin);
1351                         continue;
1352                 }
1353                 if (line[0] == '-') {
1354                         if (get_sha1_hex(line+1, sha1))
1355                                 die("expected edge sha1, got garbage:\n %s",
1356                                     line);
1357                         add_preferred_base(sha1);
1358                         continue;
1359                 }
1360                 if (get_sha1_hex(line, sha1))
1361                         die("expected sha1, got garbage:\n %s", line);
1362
1363                 hash = name_hash(line+41);
1364                 add_preferred_base_object(line+41, hash);
1365                 add_object_entry(sha1, hash, 0);
1366         }
1367 }
1368
1369 static void show_commit(struct commit *commit)
1370 {
1371         unsigned hash = name_hash("");
1372         add_preferred_base_object("", hash);
1373         add_object_entry(commit->object.sha1, hash, 0);
1374 }
1375
1376 static void show_object(struct object_array_entry *p)
1377 {
1378         unsigned hash = name_hash(p->name);
1379         add_preferred_base_object(p->name, hash);
1380         add_object_entry(p->item->sha1, hash, 0);
1381 }
1382
1383 static void show_edge(struct commit *commit)
1384 {
1385         add_preferred_base(commit->object.sha1);
1386 }
1387
1388 static void get_object_list(int ac, const char **av)
1389 {
1390         struct rev_info revs;
1391         char line[1000];
1392         int flags = 0;
1393
1394         init_revisions(&revs, NULL);
1395         save_commit_buffer = 0;
1396         track_object_refs = 0;
1397         setup_revisions(ac, av, &revs, NULL);
1398
1399         while (fgets(line, sizeof(line), stdin) != NULL) {
1400                 int len = strlen(line);
1401                 if (line[len - 1] == '\n')
1402                         line[--len] = 0;
1403                 if (!len)
1404                         break;
1405                 if (*line == '-') {
1406                         if (!strcmp(line, "--not")) {
1407                                 flags ^= UNINTERESTING;
1408                                 continue;
1409                         }
1410                         die("not a rev '%s'", line);
1411                 }
1412                 if (handle_revision_arg(line, &revs, flags, 1))
1413                         die("bad revision '%s'", line);
1414         }
1415
1416         prepare_revision_walk(&revs);
1417         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1418         traverse_commit_list(&revs, show_commit, show_object);
1419 }
1420
1421 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1422 {
1423         SHA_CTX ctx;
1424         int depth = 10;
1425         struct object_entry **list;
1426         int use_internal_rev_list = 0;
1427         int thin = 0;
1428         int i;
1429         const char *rp_av[64];
1430         int rp_ac;
1431
1432         rp_av[0] = "pack-objects";
1433         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1434         rp_ac = 2;
1435
1436         git_config(git_pack_config);
1437
1438         progress = isatty(2);
1439         for (i = 1; i < argc; i++) {
1440                 const char *arg = argv[i];
1441
1442                 if (*arg != '-')
1443                         break;
1444
1445                 if (!strcmp("--non-empty", arg)) {
1446                         non_empty = 1;
1447                         continue;
1448                 }
1449                 if (!strcmp("--local", arg)) {
1450                         local = 1;
1451                         continue;
1452                 }
1453                 if (!strcmp("--progress", arg)) {
1454                         progress = 1;
1455                         continue;
1456                 }
1457                 if (!strcmp("--incremental", arg)) {
1458                         incremental = 1;
1459                         continue;
1460                 }
1461                 if (!strncmp("--window=", arg, 9)) {
1462                         char *end;
1463                         window = strtoul(arg+9, &end, 0);
1464                         if (!arg[9] || *end)
1465                                 usage(pack_usage);
1466                         continue;
1467                 }
1468                 if (!strncmp("--depth=", arg, 8)) {
1469                         char *end;
1470                         depth = strtoul(arg+8, &end, 0);
1471                         if (!arg[8] || *end)
1472                                 usage(pack_usage);
1473                         continue;
1474                 }
1475                 if (!strcmp("--progress", arg)) {
1476                         progress = 1;
1477                         continue;
1478                 }
1479                 if (!strcmp("-q", arg)) {
1480                         progress = 0;
1481                         continue;
1482                 }
1483                 if (!strcmp("--no-reuse-delta", arg)) {
1484                         no_reuse_delta = 1;
1485                         continue;
1486                 }
1487                 if (!strcmp("--stdout", arg)) {
1488                         pack_to_stdout = 1;
1489                         continue;
1490                 }
1491                 if (!strcmp("--revs", arg)) {
1492                         use_internal_rev_list = 1;
1493                         continue;
1494                 }
1495                 if (!strcmp("--unpacked", arg) ||
1496                     !strncmp("--unpacked=", arg, 11) ||
1497                     !strcmp("--all", arg)) {
1498                         use_internal_rev_list = 1;
1499                         if (ARRAY_SIZE(rp_av) - 1 <= rp_ac)
1500                                 die("too many internal rev-list options");
1501                         rp_av[rp_ac++] = arg;
1502                         continue;
1503                 }
1504                 if (!strcmp("--thin", arg)) {
1505                         use_internal_rev_list = 1;
1506                         thin = 1;
1507                         rp_av[1] = "--objects-edge";
1508                         continue;
1509                 }
1510                 usage(pack_usage);
1511         }
1512
1513         /* Traditionally "pack-objects [options] base extra" failed;
1514          * we would however want to take refs parameter that would
1515          * have been given to upstream rev-list ourselves, which means
1516          * we somehow want to say what the base name is.  So the
1517          * syntax would be:
1518          *
1519          * pack-objects [options] base <refs...>
1520          *
1521          * in other words, we would treat the first non-option as the
1522          * base_name and send everything else to the internal revision
1523          * walker.
1524          */
1525
1526         if (!pack_to_stdout)
1527                 base_name = argv[i++];
1528
1529         if (pack_to_stdout != !base_name)
1530                 usage(pack_usage);
1531
1532         if (!pack_to_stdout && thin)
1533                 die("--thin cannot be used to build an indexable pack.");
1534
1535         prepare_packed_git();
1536
1537         if (progress) {
1538                 fprintf(stderr, "Generating pack...\n");
1539                 setup_progress_signal();
1540         }
1541
1542         if (!use_internal_rev_list)
1543                 read_object_list_from_stdin();
1544         else {
1545                 rp_av[rp_ac] = NULL;
1546                 get_object_list(rp_ac, rp_av);
1547         }
1548
1549         if (progress)
1550                 fprintf(stderr, "Done counting %d objects.\n", nr_objects);
1551         sorted_by_sha = create_final_object_list();
1552         if (non_empty && !nr_result)
1553                 return 0;
1554
1555         SHA1_Init(&ctx);
1556         list = sorted_by_sha;
1557         for (i = 0; i < nr_result; i++) {
1558                 struct object_entry *entry = *list++;
1559                 SHA1_Update(&ctx, entry->sha1, 20);
1560         }
1561         SHA1_Final(object_list_sha1, &ctx);
1562         if (progress && (nr_objects != nr_result))
1563                 fprintf(stderr, "Result has %d objects.\n", nr_result);
1564
1565         if (reuse_cached_pack(object_list_sha1))
1566                 ;
1567         else {
1568                 if (nr_result)
1569                         prepare_pack(window, depth);
1570                 if (progress && pack_to_stdout) {
1571                         /* the other end usually displays progress itself */
1572                         struct itimerval v = {{0,},};
1573                         setitimer(ITIMER_REAL, &v, NULL);
1574                         signal(SIGALRM, SIG_IGN );
1575                         progress_update = 0;
1576                 }
1577                 write_pack_file();
1578                 if (!pack_to_stdout) {
1579                         write_index_file();
1580                         puts(sha1_to_hex(object_list_sha1));
1581                 }
1582         }
1583         if (progress)
1584                 fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n",
1585                         nr_result, written, written_delta, reused, reused_delta);
1586         return 0;
1587 }