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
  16 static const char pack_usage[] = "\
  17 git-pack-objects [{ -q | --progress | --all-progress }] \n\
  18         [--local] [--incremental] [--window=N] [--depth=N] \n\
  19         [--no-reuse-delta] [--delta-base-offset] [--non-empty] \n\
  20         [--revs [--unpacked | --all]*] [--reflog] [--stdout | base-name] \n\
  21         [<ref-list | <object-list]";
  22
  23 struct object_entry {
  24         unsigned char sha1[20];
  25         unsigned long size;     /* uncompressed size */
  26         off_t offset;   /* offset into the final pack file;
  27                                  * nonzero if already written.
  28                                  */
  29         unsigned int depth;     /* delta depth */
  30         unsigned int delta_limit;       /* base adjustment for in-pack delta */
  31         unsigned int hash;      /* name hint hash */
  32         enum object_type type;
  33         enum object_type in_pack_type;  /* could be delta */
  34         unsigned long delta_size;       /* delta data size (uncompressed) */
  35 #define in_pack_header_size delta_size  /* only when reusing pack data */
  36         struct object_entry *delta;     /* delta base object */
  37         struct packed_git *in_pack;     /* already in pack */
  38         off_t in_pack_offset;
  39         struct object_entry *delta_child; /* deltified objects who bases me */
  40         struct object_entry *delta_sibling; /* other deltified objects who
  41                                              * uses the same base as me
  42                                              */
  43         int preferred_base;     /* we do not pack this, but is encouraged to
  44                                  * be used as the base objectto delta huge
  45                                  * objects against.
  46                                  */
  47 };
  48
  49 /*
  50  * Objects we are going to pack are collected in objects array (dynamically
  51  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  52  * in the order we see -- typically rev-list --objects order that gives us
  53  * nice "minimum seek" order.
  54  *
  55  * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
  56  * elements in the objects array.  The former is used to build the pack
  57  * index (lists object names in the ascending order to help offset lookup),
  58  * and the latter is used to group similar things together by try_delta()
  59  * heuristics.
  60  */
  61
  62 static unsigned char object_list_sha1[20];
  63 static int non_empty;
  64 static int no_reuse_delta;
  65 static int local;
  66 static int incremental;
  67 static int allow_ofs_delta;
  68
  69 static struct object_entry **sorted_by_sha, **sorted_by_type;
  70 static struct object_entry *objects;
  71 static uint32_t nr_objects, nr_alloc, nr_result;
  72 static const char *base_name;
  73 static unsigned char pack_file_sha1[20];
  74 static int progress = 1;
  75 static volatile sig_atomic_t progress_update;
  76 static int window = 10;
  77 static int pack_to_stdout;
  78 static int num_preferred_base;
  79
  80 /*
  81  * The object names in objects array are hashed with this hashtable,
  82  * to help looking up the entry by object name.  Binary search from
  83  * sorted_by_sha is also possible but this was easier to code and faster.
  84  * This hashtable is built after all the objects are seen.
  85  */
  86 static int *object_ix;
  87 static int object_ix_hashsz;
  88
  89 /*
  90  * Pack index for existing packs give us easy access to the offsets into
  91  * corresponding pack file where each object's data starts, but the entries
  92  * do not store the size of the compressed representation (uncompressed
  93  * size is easily available by examining the pack entry header).  It is
  94  * also rather expensive to find the sha1 for an object given its offset.
  95  *
  96  * We build a hashtable of existing packs (pack_revindex), and keep reverse
  97  * index here -- pack index file is sorted by object name mapping to offset;
  98  * this pack_revindex[].revindex array is a list of offset/index_nr pairs
  99  * ordered by offset, so if you know the offset of an object, next offset
 100  * is where its packed representation ends and the index_nr can be used to
 101  * get the object sha1 from the main index.
 102  */
 103 struct revindex_entry {
 104         off_t offset;
 105         unsigned int nr;
 106 };
 107 struct pack_revindex {
 108         struct packed_git *p;
 109         struct revindex_entry *revindex;
 110 };
 111 static struct  pack_revindex *pack_revindex;
 112 static int pack_revindex_hashsz;
 113
 114 /*
 115  * stats
 116  */
 117 static uint32_t written, written_delta;
 118 static uint32_t reused, reused_delta;
 119
 120 static int pack_revindex_ix(struct packed_git *p)
 121 {
 122         unsigned long ui = (unsigned long)p;
 123         int i;
 124
 125         ui = ui ^ (ui >> 16); /* defeat structure alignment */
 126         i = (int)(ui % pack_revindex_hashsz);
 127         while (pack_revindex[i].p) {
 128                 if (pack_revindex[i].p == p)
 129                         return i;
 130                 if (++i == pack_revindex_hashsz)
 131                         i = 0;
 132         }
 133         return -1 - i;
 134 }
 135
 136 static void prepare_pack_ix(void)
 137 {
 138         int num;
 139         struct packed_git *p;
 140         for (num = 0, p = packed_git; p; p = p->next)
 141                 num++;
 142         if (!num)
 143                 return;
 144         pack_revindex_hashsz = num * 11;
 145         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 146         for (p = packed_git; p; p = p->next) {
 147                 num = pack_revindex_ix(p);
 148                 num = - 1 - num;
 149                 pack_revindex[num].p = p;
 150         }
 151         /* revindex elements are lazily initialized */
 152 }
 153
 154 static int cmp_offset(const void *a_, const void *b_)
 155 {
 156         const struct revindex_entry *a = a_;
 157         const struct revindex_entry *b = b_;
 158         return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
 159 }
 160
 161 /*
 162  * Ordered list of offsets of objects in the pack.
 163  */
 164 static void prepare_pack_revindex(struct pack_revindex *rix)
 165 {
 166         struct packed_git *p = rix->p;
 167         int num_ent = num_packed_objects(p);
 168         int i;
 169         void *index = p->index_base + 256;
 170
 171         rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
 172         for (i = 0; i < num_ent; i++) {
 173                 unsigned int hl = *((unsigned int *)((char *) index + 24*i));
 174                 rix->revindex[i].offset = ntohl(hl);
 175                 rix->revindex[i].nr = i;
 176         }
 177         /* This knows the pack format -- the 20-byte trailer
 178          * follows immediately after the last object data.
 179          */
 180         rix->revindex[num_ent].offset = p->pack_size - 20;
 181         rix->revindex[num_ent].nr = -1;
 182         qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
 183 }
 184
 185 static struct revindex_entry * find_packed_object(struct packed_git *p,
 186                                                   off_t ofs)
 187 {
 188         int num;
 189         int lo, hi;
 190         struct pack_revindex *rix;
 191         struct revindex_entry *revindex;
 192         num = pack_revindex_ix(p);
 193         if (num < 0)
 194                 die("internal error: pack revindex uninitialized");
 195         rix = &pack_revindex[num];
 196         if (!rix->revindex)
 197                 prepare_pack_revindex(rix);
 198         revindex = rix->revindex;
 199         lo = 0;
 200         hi = num_packed_objects(p) + 1;
 201         do {
 202                 int mi = (lo + hi) / 2;
 203                 if (revindex[mi].offset == ofs) {
 204                         return revindex + mi;
 205                 }
 206                 else if (ofs < revindex[mi].offset)
 207                         hi = mi;
 208                 else
 209                         lo = mi + 1;
 210         } while (lo < hi);
 211         die("internal error: pack revindex corrupt");
 212 }
 213
 214 static off_t find_packed_object_size(struct packed_git *p, off_t ofs)
 215 {
 216         struct revindex_entry *entry = find_packed_object(p, ofs);
 217         return entry[1].offset - ofs;
 218 }
 219
 220 static unsigned char *find_packed_object_name(struct packed_git *p,
 221                                               off_t ofs)
 222 {
 223         struct revindex_entry *entry = find_packed_object(p, ofs);
 224         return (unsigned char *)(p->index_base + 256) + 24 * entry->nr + 4;
 225 }
 226
 227 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 228 {
 229         unsigned long othersize, delta_size;
 230         enum object_type type;
 231         void *otherbuf = read_sha1_file(entry->delta->sha1, &type, &othersize);
 232         void *delta_buf;
 233
 234         if (!otherbuf)
 235                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 236         delta_buf = diff_delta(otherbuf, othersize,
 237                                buf, size, &delta_size, 0);
 238         if (!delta_buf || delta_size != entry->delta_size)
 239                 die("delta size changed");
 240         free(buf);
 241         free(otherbuf);
 242         return delta_buf;
 243 }
 244
 245 /*
 246  * The per-object header is a pretty dense thing, which is
 247  *  - first byte: low four bits are "size", then three bits of "type",
 248  *    and the high bit is "size continues".
 249  *  - each byte afterwards: low seven bits are size continuation,
 250  *    with the high bit being "size continues"
 251  */
 252 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 253 {
 254         int n = 1;
 255         unsigned char c;
 256
 257         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 258                 die("bad type %d", type);
 259
 260         c = (type << 4) | (size & 15);
 261         size >>= 4;
 262         while (size) {
 263                 *hdr++ = c | 0x80;
 264                 c = size & 0x7f;
 265                 size >>= 7;
 266                 n++;
 267         }
 268         *hdr = c;
 269         return n;
 270 }
 271
 272 /*
 273  * we are going to reuse the existing object data as is.  make
 274  * sure it is not corrupt.
 275  */
 276 static int check_pack_inflate(struct packed_git *p,
 277                 struct pack_window **w_curs,
 278                 off_t offset,
 279                 off_t len,
 280                 unsigned long expect)
 281 {
 282         z_stream stream;
 283         unsigned char fakebuf[4096], *in;
 284         int st;
 285
 286         memset(&stream, 0, sizeof(stream));
 287         inflateInit(&stream);
 288         do {
 289                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 290                 stream.next_in = in;
 291                 stream.next_out = fakebuf;
 292                 stream.avail_out = sizeof(fakebuf);
 293                 st = inflate(&stream, Z_FINISH);
 294                 offset += stream.next_in - in;
 295         } while (st == Z_OK || st == Z_BUF_ERROR);
 296         inflateEnd(&stream);
 297         return (st == Z_STREAM_END &&
 298                 stream.total_out == expect &&
 299                 stream.total_in == len) ? 0 : -1;
 300 }
 301
 302 static void copy_pack_data(struct sha1file *f,
 303                 struct packed_git *p,
 304                 struct pack_window **w_curs,
 305                 off_t offset,
 306                 off_t len)
 307 {
 308         unsigned char *in;
 309         unsigned int avail;
 310
 311         while (len) {
 312                 in = use_pack(p, w_curs, offset, &avail);
 313                 if (avail > len)
 314                         avail = (unsigned int)len;
 315                 sha1write(f, in, avail);
 316                 offset += avail;
 317                 len -= avail;
 318         }
 319 }
 320
 321 static int check_loose_inflate(unsigned char *data, unsigned long len, unsigned long expect)
 322 {
 323         z_stream stream;
 324         unsigned char fakebuf[4096];
 325         int st;
 326
 327         memset(&stream, 0, sizeof(stream));
 328         stream.next_in = data;
 329         stream.avail_in = len;
 330         stream.next_out = fakebuf;
 331         stream.avail_out = sizeof(fakebuf);
 332         inflateInit(&stream);
 333
 334         while (1) {
 335                 st = inflate(&stream, Z_FINISH);
 336                 if (st == Z_STREAM_END || st == Z_OK) {
 337                         st = (stream.total_out == expect &&
 338                               stream.total_in == len) ? 0 : -1;
 339                         break;
 340                 }
 341                 if (st != Z_BUF_ERROR) {
 342                         st = -1;
 343                         break;
 344                 }
 345                 stream.next_out = fakebuf;
 346                 stream.avail_out = sizeof(fakebuf);
 347         }
 348         inflateEnd(&stream);
 349         return st;
 350 }
 351
 352 static int revalidate_loose_object(struct object_entry *entry,
 353                                    unsigned char *map,
 354                                    unsigned long mapsize)
 355 {
 356         /* we already know this is a loose object with new type header. */
 357         enum object_type type;
 358         unsigned long size, used;
 359
 360         if (pack_to_stdout)
 361                 return 0;
 362
 363         used = unpack_object_header_gently(map, mapsize, &type, &size);
 364         if (!used)
 365                 return -1;
 366         map += used;
 367         mapsize -= used;
 368         return check_loose_inflate(map, mapsize, size);
 369 }
 370
 371 static off_t write_object(struct sha1file *f,
 372                                   struct object_entry *entry)
 373 {
 374         unsigned long size;
 375         enum object_type type;
 376         void *buf;
 377         unsigned char header[10];
 378         unsigned hdrlen;
 379         off_t datalen;
 380         enum object_type obj_type;
 381         int to_reuse = 0;
 382
 383         obj_type = entry->type;
 384         if (! entry->in_pack)
 385                 to_reuse = 0;   /* can't reuse what we don't have */
 386         else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 387                 to_reuse = 1;   /* check_object() decided it for us */
 388         else if (obj_type != entry->in_pack_type)
 389                 to_reuse = 0;   /* pack has delta which is unusable */
 390         else if (entry->delta)
 391                 to_reuse = 0;   /* we want to pack afresh */
 392         else
 393                 to_reuse = 1;   /* we have it in-pack undeltified,
 394                                  * and we do not need to deltify it.
 395                                  */
 396
 397         if (!entry->in_pack && !entry->delta) {
 398                 unsigned char *map;
 399                 unsigned long mapsize;
 400                 map = map_sha1_file(entry->sha1, &mapsize);
 401                 if (map && !legacy_loose_object(map)) {
 402                         /* We can copy straight into the pack file */
 403                         if (revalidate_loose_object(entry, map, mapsize))
 404                                 die("corrupt loose object %s",
 405                                     sha1_to_hex(entry->sha1));
 406                         sha1write(f, map, mapsize);
 407                         munmap(map, mapsize);
 408                         written++;
 409                         reused++;
 410                         return mapsize;
 411                 }
 412                 if (map)
 413                         munmap(map, mapsize);
 414         }
 415
 416         if (!to_reuse) {
 417                 buf = read_sha1_file(entry->sha1, &type, &size);
 418                 if (!buf)
 419                         die("unable to read %s", sha1_to_hex(entry->sha1));
 420                 if (size != entry->size)
 421                         die("object %s size inconsistency (%lu vs %lu)",
 422                             sha1_to_hex(entry->sha1), size, entry->size);
 423                 if (entry->delta) {
 424                         buf = delta_against(buf, size, entry);
 425                         size = entry->delta_size;
 426                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 427                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 428                 }
 429                 /*
 430                  * The object header is a byte of 'type' followed by zero or
 431                  * more bytes of length.
 432                  */
 433                 hdrlen = encode_header(obj_type, size, header);
 434                 sha1write(f, header, hdrlen);
 435
 436                 if (obj_type == OBJ_OFS_DELTA) {
 437                         /*
 438                          * Deltas with relative base contain an additional
 439                          * encoding of the relative offset for the delta
 440                          * base from this object's position in the pack.
 441                          */
 442                         off_t ofs = entry->offset - entry->delta->offset;
 443                         unsigned pos = sizeof(header) - 1;
 444                         header[pos] = ofs & 127;
 445                         while (ofs >>= 7)
 446                                 header[--pos] = 128 | (--ofs & 127);
 447                         sha1write(f, header + pos, sizeof(header) - pos);
 448                         hdrlen += sizeof(header) - pos;
 449                 } else if (obj_type == OBJ_REF_DELTA) {
 450                         /*
 451                          * Deltas with a base reference contain
 452                          * an additional 20 bytes for the base sha1.
 453                          */
 454                         sha1write(f, entry->delta->sha1, 20);
 455                         hdrlen += 20;
 456                 }
 457                 datalen = sha1write_compressed(f, buf, size);
 458                 free(buf);
 459         }
 460         else {
 461                 struct packed_git *p = entry->in_pack;
 462                 struct pack_window *w_curs = NULL;
 463                 off_t offset;
 464
 465                 if (entry->delta) {
 466                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 467                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 468                         reused_delta++;
 469                 }
 470                 hdrlen = encode_header(obj_type, entry->size, header);
 471                 sha1write(f, header, hdrlen);
 472                 if (obj_type == OBJ_OFS_DELTA) {
 473                         off_t ofs = entry->offset - entry->delta->offset;
 474                         unsigned pos = sizeof(header) - 1;
 475                         header[pos] = ofs & 127;
 476                         while (ofs >>= 7)
 477                                 header[--pos] = 128 | (--ofs & 127);
 478                         sha1write(f, header + pos, sizeof(header) - pos);
 479                         hdrlen += sizeof(header) - pos;
 480                 } else if (obj_type == OBJ_REF_DELTA) {
 481                         sha1write(f, entry->delta->sha1, 20);
 482                         hdrlen += 20;
 483                 }
 484
 485                 offset = entry->in_pack_offset + entry->in_pack_header_size;
 486                 datalen = find_packed_object_size(p, entry->in_pack_offset)
 487                                 - entry->in_pack_header_size;
 488                 if (!pack_to_stdout && check_pack_inflate(p, &w_curs,
 489                                 offset, datalen, entry->size))
 490                         die("corrupt delta in pack %s", sha1_to_hex(entry->sha1));
 491                 copy_pack_data(f, p, &w_curs, offset, datalen);
 492                 unuse_pack(&w_curs);
 493                 reused++;
 494         }
 495         if (entry->delta)
 496                 written_delta++;
 497         written++;
 498         return hdrlen + datalen;
 499 }
 500
 501 static off_t write_one(struct sha1file *f,
 502                                struct object_entry *e,
 503                                off_t offset)
 504 {
 505         if (e->offset || e->preferred_base)
 506                 /* offset starts from header size and cannot be zero
 507                  * if it is written already.
 508                  */
 509                 return offset;
 510         /* if we are deltified, write out its base object first. */
 511         if (e->delta)
 512                 offset = write_one(f, e->delta, offset);
 513         e->offset = offset;
 514         return offset + write_object(f, e);
 515 }
 516
 517 static void write_pack_file(void)
 518 {
 519         uint32_t i;
 520         struct sha1file *f;
 521         off_t offset;
 522         struct pack_header hdr;
 523         unsigned last_percent = 999;
 524         int do_progress = progress;
 525
 526         if (!base_name) {
 527                 f = sha1fd(1, "<stdout>");
 528                 do_progress >>= 1;
 529         }
 530         else
 531                 f = sha1create("%s-%s.%s", base_name,
 532                                sha1_to_hex(object_list_sha1), "pack");
 533         if (do_progress)
 534                 fprintf(stderr, "Writing %u objects.\n", nr_result);
 535
 536         hdr.hdr_signature = htonl(PACK_SIGNATURE);
 537         hdr.hdr_version = htonl(PACK_VERSION);
 538         hdr.hdr_entries = htonl(nr_result);
 539         sha1write(f, &hdr, sizeof(hdr));
 540         offset = sizeof(hdr);
 541         if (!nr_result)
 542                 goto done;
 543         for (i = 0; i < nr_objects; i++) {
 544                 offset = write_one(f, objects + i, offset);
 545                 if (do_progress) {
 546                         unsigned percent = written * 100 / nr_result;
 547                         if (progress_update || percent != last_percent) {
 548                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
 549                                         percent, written, nr_result);
 550                                 progress_update = 0;
 551                                 last_percent = percent;
 552                         }
 553                 }
 554         }
 555         if (do_progress)
 556                 fputc('\n', stderr);
 557  done:
 558         if (written != nr_result)
 559                 die("wrote %u objects while expecting %u", written, nr_result);
 560         sha1close(f, pack_file_sha1, 1);
 561 }
 562
 563 static void write_index_file(void)
 564 {
 565         uint32_t i;
 566         struct sha1file *f = sha1create("%s-%s.%s", base_name,
 567                                         sha1_to_hex(object_list_sha1), "idx");
 568         struct object_entry **list = sorted_by_sha;
 569         struct object_entry **last = list + nr_result;
 570         uint32_t array[256];
 571
 572         /*
 573          * Write the first-level table (the list is sorted,
 574          * but we use a 256-entry lookup to be able to avoid
 575          * having to do eight extra binary search iterations).
 576          */
 577         for (i = 0; i < 256; i++) {
 578                 struct object_entry **next = list;
 579                 while (next < last) {
 580                         struct object_entry *entry = *next;
 581                         if (entry->sha1[0] != i)
 582                                 break;
 583                         next++;
 584                 }
 585                 array[i] = htonl(next - sorted_by_sha);
 586                 list = next;
 587         }
 588         sha1write(f, array, 256 * 4);
 589
 590         /*
 591          * Write the actual SHA1 entries..
 592          */
 593         list = sorted_by_sha;
 594         for (i = 0; i < nr_result; i++) {
 595                 struct object_entry *entry = *list++;
 596                 uint32_t offset = htonl(entry->offset);
 597                 sha1write(f, &offset, 4);
 598                 sha1write(f, entry->sha1, 20);
 599         }
 600         sha1write(f, pack_file_sha1, 20);
 601         sha1close(f, NULL, 1);
 602 }
 603
 604 static int locate_object_entry_hash(const unsigned char *sha1)
 605 {
 606         int i;
 607         unsigned int ui;
 608         memcpy(&ui, sha1, sizeof(unsigned int));
 609         i = ui % object_ix_hashsz;
 610         while (0 < object_ix[i]) {
 611                 if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
 612                         return i;
 613                 if (++i == object_ix_hashsz)
 614                         i = 0;
 615         }
 616         return -1 - i;
 617 }
 618
 619 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 620 {
 621         int i;
 622
 623         if (!object_ix_hashsz)
 624                 return NULL;
 625
 626         i = locate_object_entry_hash(sha1);
 627         if (0 <= i)
 628                 return &objects[object_ix[i]-1];
 629         return NULL;
 630 }
 631
 632 static void rehash_objects(void)
 633 {
 634         uint32_t i;
 635         struct object_entry *oe;
 636
 637         object_ix_hashsz = nr_objects * 3;
 638         if (object_ix_hashsz < 1024)
 639                 object_ix_hashsz = 1024;
 640         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 641         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 642         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 643                 int ix = locate_object_entry_hash(oe->sha1);
 644                 if (0 <= ix)
 645                         continue;
 646                 ix = -1 - ix;
 647                 object_ix[ix] = i + 1;
 648         }
 649 }
 650
 651 static unsigned name_hash(const char *name)
 652 {
 653         unsigned char c;
 654         unsigned hash = 0;
 655
 656         /*
 657          * This effectively just creates a sortable number from the
 658          * last sixteen non-whitespace characters. Last characters
 659          * count "most", so things that end in ".c" sort together.
 660          */
 661         while ((c = *name++) != 0) {
 662                 if (isspace(c))
 663                         continue;
 664                 hash = (hash >> 2) + (c << 24);
 665         }
 666         return hash;
 667 }
 668
 669 static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 670 {
 671         uint32_t idx = nr_objects;
 672         struct object_entry *entry;
 673         struct packed_git *p;
 674         off_t found_offset = 0;
 675         struct packed_git *found_pack = NULL;
 676         int ix, status = 0;
 677
 678         if (!exclude) {
 679                 for (p = packed_git; p; p = p->next) {
 680                         off_t offset = find_pack_entry_one(sha1, p);
 681                         if (offset) {
 682                                 if (incremental)
 683                                         return 0;
 684                                 if (local && !p->pack_local)
 685                                         return 0;
 686                                 if (!found_pack) {
 687                                         found_offset = offset;
 688                                         found_pack = p;
 689                                 }
 690                         }
 691                 }
 692         }
 693         if ((entry = locate_object_entry(sha1)) != NULL)
 694                 goto already_added;
 695
 696         if (idx >= nr_alloc) {
 697                 nr_alloc = (idx + 1024) * 3 / 2;
 698                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 699         }
 700         entry = objects + idx;
 701         nr_objects = idx + 1;
 702         memset(entry, 0, sizeof(*entry));
 703         hashcpy(entry->sha1, sha1);
 704         entry->hash = hash;
 705
 706         if (object_ix_hashsz * 3 <= nr_objects * 4)
 707                 rehash_objects();
 708         else {
 709                 ix = locate_object_entry_hash(entry->sha1);
 710                 if (0 <= ix)
 711                         die("internal error in object hashing.");
 712                 object_ix[-1 - ix] = idx + 1;
 713         }
 714         status = 1;
 715
 716  already_added:
 717         if (progress_update) {
 718                 fprintf(stderr, "Counting objects...%u\r", nr_objects);
 719                 progress_update = 0;
 720         }
 721         if (exclude)
 722                 entry->preferred_base = 1;
 723         else {
 724                 if (found_pack) {
 725                         entry->in_pack = found_pack;
 726                         entry->in_pack_offset = found_offset;
 727                 }
 728         }
 729         return status;
 730 }
 731
 732 struct pbase_tree_cache {
 733         unsigned char sha1[20];
 734         int ref;
 735         int temporary;
 736         void *tree_data;
 737         unsigned long tree_size;
 738 };
 739
 740 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 741 static int pbase_tree_cache_ix(const unsigned char *sha1)
 742 {
 743         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 744 }
 745 static int pbase_tree_cache_ix_incr(int ix)
 746 {
 747         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 748 }
 749
 750 static struct pbase_tree {
 751         struct pbase_tree *next;
 752         /* This is a phony "cache" entry; we are not
 753          * going to evict it nor find it through _get()
 754          * mechanism -- this is for the toplevel node that
 755          * would almost always change with any commit.
 756          */
 757         struct pbase_tree_cache pcache;
 758 } *pbase_tree;
 759
 760 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 761 {
 762         struct pbase_tree_cache *ent, *nent;
 763         void *data;
 764         unsigned long size;
 765         enum object_type type;
 766         int neigh;
 767         int my_ix = pbase_tree_cache_ix(sha1);
 768         int available_ix = -1;
 769
 770         /* pbase-tree-cache acts as a limited hashtable.
 771          * your object will be found at your index or within a few
 772          * slots after that slot if it is cached.
 773          */
 774         for (neigh = 0; neigh < 8; neigh++) {
 775                 ent = pbase_tree_cache[my_ix];
 776                 if (ent && !hashcmp(ent->sha1, sha1)) {
 777                         ent->ref++;
 778                         return ent;
 779                 }
 780                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 781                          ((0 <= available_ix) &&
 782                           (!ent && pbase_tree_cache[available_ix])))
 783                         available_ix = my_ix;
 784                 if (!ent)
 785                         break;
 786                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 787         }
 788
 789         /* Did not find one.  Either we got a bogus request or
 790          * we need to read and perhaps cache.
 791          */
 792         data = read_sha1_file(sha1, &type, &size);
 793         if (!data)
 794                 return NULL;
 795         if (type != OBJ_TREE) {
 796                 free(data);
 797                 return NULL;
 798         }
 799
 800         /* We need to either cache or return a throwaway copy */
 801
 802         if (available_ix < 0)
 803                 ent = NULL;
 804         else {
 805                 ent = pbase_tree_cache[available_ix];
 806                 my_ix = available_ix;
 807         }
 808
 809         if (!ent) {
 810                 nent = xmalloc(sizeof(*nent));
 811                 nent->temporary = (available_ix < 0);
 812         }
 813         else {
 814                 /* evict and reuse */
 815                 free(ent->tree_data);
 816                 nent = ent;
 817         }
 818         hashcpy(nent->sha1, sha1);
 819         nent->tree_data = data;
 820         nent->tree_size = size;
 821         nent->ref = 1;
 822         if (!nent->temporary)
 823                 pbase_tree_cache[my_ix] = nent;
 824         return nent;
 825 }
 826
 827 static void pbase_tree_put(struct pbase_tree_cache *cache)
 828 {
 829         if (!cache->temporary) {
 830                 cache->ref--;
 831                 return;
 832         }
 833         free(cache->tree_data);
 834         free(cache);
 835 }
 836
 837 static int name_cmp_len(const char *name)
 838 {
 839         int i;
 840         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 841                 ;
 842         return i;
 843 }
 844
 845 static void add_pbase_object(struct tree_desc *tree,
 846                              const char *name,
 847                              int cmplen,
 848                              const char *fullname)
 849 {
 850         struct name_entry entry;
 851
 852         while (tree_entry(tree,&entry)) {
 853                 unsigned long size;
 854                 enum object_type type;
 855
 856                 if (entry.pathlen != cmplen ||
 857                     memcmp(entry.path, name, cmplen) ||
 858                     !has_sha1_file(entry.sha1) ||
 859                     (type = sha1_object_info(entry.sha1, &size)) < 0)
 860                         continue;
 861                 if (name[cmplen] != '/') {
 862                         unsigned hash = name_hash(fullname);
 863                         add_object_entry(entry.sha1, hash, 1);
 864                         return;
 865                 }
 866                 if (type == OBJ_TREE) {
 867                         struct tree_desc sub;
 868                         struct pbase_tree_cache *tree;
 869                         const char *down = name+cmplen+1;
 870                         int downlen = name_cmp_len(down);
 871
 872                         tree = pbase_tree_get(entry.sha1);
 873                         if (!tree)
 874                                 return;
 875                         sub.buf = tree->tree_data;
 876                         sub.size = tree->tree_size;
 877
 878                         add_pbase_object(&sub, down, downlen, fullname);
 879                         pbase_tree_put(tree);
 880                 }
 881         }
 882 }
 883
 884 static unsigned *done_pbase_paths;
 885 static int done_pbase_paths_num;
 886 static int done_pbase_paths_alloc;
 887 static int done_pbase_path_pos(unsigned hash)
 888 {
 889         int lo = 0;
 890         int hi = done_pbase_paths_num;
 891         while (lo < hi) {
 892                 int mi = (hi + lo) / 2;
 893                 if (done_pbase_paths[mi] == hash)
 894                         return mi;
 895                 if (done_pbase_paths[mi] < hash)
 896                         hi = mi;
 897                 else
 898                         lo = mi + 1;
 899         }
 900         return -lo-1;
 901 }
 902
 903 static int check_pbase_path(unsigned hash)
 904 {
 905         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 906         if (0 <= pos)
 907                 return 1;
 908         pos = -pos - 1;
 909         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 910                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 911                 done_pbase_paths = xrealloc(done_pbase_paths,
 912                                             done_pbase_paths_alloc *
 913                                             sizeof(unsigned));
 914         }
 915         done_pbase_paths_num++;
 916         if (pos < done_pbase_paths_num)
 917                 memmove(done_pbase_paths + pos + 1,
 918                         done_pbase_paths + pos,
 919                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 920         done_pbase_paths[pos] = hash;
 921         return 0;
 922 }
 923
 924 static void add_preferred_base_object(const char *name, unsigned hash)
 925 {
 926         struct pbase_tree *it;
 927         int cmplen = name_cmp_len(name);
 928
 929         if (check_pbase_path(hash))
 930                 return;
 931
 932         for (it = pbase_tree; it; it = it->next) {
 933                 if (cmplen == 0) {
 934                         hash = name_hash("");
 935                         add_object_entry(it->pcache.sha1, hash, 1);
 936                 }
 937                 else {
 938                         struct tree_desc tree;
 939                         tree.buf = it->pcache.tree_data;
 940                         tree.size = it->pcache.tree_size;
 941                         add_pbase_object(&tree, name, cmplen, name);
 942                 }
 943         }
 944 }
 945
 946 static void add_preferred_base(unsigned char *sha1)
 947 {
 948         struct pbase_tree *it;
 949         void *data;
 950         unsigned long size;
 951         unsigned char tree_sha1[20];
 952
 953         if (window <= num_preferred_base++)
 954                 return;
 955
 956         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 957         if (!data)
 958                 return;
 959
 960         for (it = pbase_tree; it; it = it->next) {
 961                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
 962                         free(data);
 963                         return;
 964                 }
 965         }
 966
 967         it = xcalloc(1, sizeof(*it));
 968         it->next = pbase_tree;
 969         pbase_tree = it;
 970
 971         hashcpy(it->pcache.sha1, tree_sha1);
 972         it->pcache.tree_data = data;
 973         it->pcache.tree_size = size;
 974 }
 975
 976 static void check_object(struct object_entry *entry)
 977 {
 978         if (entry->in_pack && !entry->preferred_base) {
 979                 struct packed_git *p = entry->in_pack;
 980                 struct pack_window *w_curs = NULL;
 981                 unsigned long size, used;
 982                 unsigned int avail;
 983                 unsigned char *buf;
 984                 struct object_entry *base_entry = NULL;
 985
 986                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
 987
 988                 /* We want in_pack_type even if we do not reuse delta.
 989                  * There is no point not reusing non-delta representations.
 990                  */
 991                 used = unpack_object_header_gently(buf, avail,
 992                                                    &entry->in_pack_type, &size);
 993
 994                 /* Check if it is delta, and the base is also an object
 995                  * we are going to pack.  If so we will reuse the existing
 996                  * delta.
 997                  */
 998                 if (!no_reuse_delta) {
 999                         unsigned char c, *base_name;
1000                         off_t ofs;
1001                         unsigned long used_0;
1002                         /* there is at least 20 bytes left in the pack */
1003                         switch (entry->in_pack_type) {
1004                         case OBJ_REF_DELTA:
1005                                 base_name = use_pack(p, &w_curs,
1006                                         entry->in_pack_offset + used, NULL);
1007                                 used += 20;
1008                                 break;
1009                         case OBJ_OFS_DELTA:
1010                                 buf = use_pack(p, &w_curs,
1011                                         entry->in_pack_offset + used, NULL);
1012                                 used_0 = 0;
1013                                 c = buf[used_0++];
1014                                 ofs = c & 127;
1015                                 while (c & 128) {
1016                                         ofs += 1;
1017                                         if (!ofs || ofs & ~(~0UL >> 7))
1018                                                 die("delta base offset overflow in pack for %s",
1019                                                     sha1_to_hex(entry->sha1));
1020                                         c = buf[used_0++];
1021                                         ofs = (ofs << 7) + (c & 127);
1022                                 }
1023                                 if (ofs >= entry->in_pack_offset)
1024                                         die("delta base offset out of bound for %s",
1025                                             sha1_to_hex(entry->sha1));
1026                                 ofs = entry->in_pack_offset - ofs;
1027                                 base_name = find_packed_object_name(p, ofs);
1028                                 used += used_0;
1029                                 break;
1030                         default:
1031                                 base_name = NULL;
1032                         }
1033                         if (base_name)
1034                                 base_entry = locate_object_entry(base_name);
1035                 }
1036                 unuse_pack(&w_curs);
1037                 entry->in_pack_header_size = used;
1038
1039                 if (base_entry) {
1040
1041                         /* Depth value does not matter - find_deltas()
1042                          * will never consider reused delta as the
1043                          * base object to deltify other objects
1044                          * against, in order to avoid circular deltas.
1045                          */
1046
1047                         /* uncompressed size of the delta data */
1048                         entry->size = size;
1049                         entry->delta = base_entry;
1050                         entry->type = entry->in_pack_type;
1051
1052                         entry->delta_sibling = base_entry->delta_child;
1053                         base_entry->delta_child = entry;
1054
1055                         return;
1056                 }
1057                 /* Otherwise we would do the usual */
1058         }
1059
1060         entry->type = sha1_object_info(entry->sha1, &entry->size);
1061         if (entry->type < 0)
1062                 die("unable to get type of object %s",
1063                     sha1_to_hex(entry->sha1));
1064 }
1065
1066 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1067 {
1068         struct object_entry *child = me->delta_child;
1069         unsigned int m = n;
1070         while (child) {
1071                 unsigned int c = check_delta_limit(child, n + 1);
1072                 if (m < c)
1073                         m = c;
1074                 child = child->delta_sibling;
1075         }
1076         return m;
1077 }
1078
1079 static void get_object_details(void)
1080 {
1081         uint32_t i;
1082         struct object_entry *entry;
1083
1084         prepare_pack_ix();
1085         for (i = 0, entry = objects; i < nr_objects; i++, entry++)
1086                 check_object(entry);
1087
1088         if (nr_objects == nr_result) {
1089                 /*
1090                  * Depth of objects that depend on the entry -- this
1091                  * is subtracted from depth-max to break too deep
1092                  * delta chain because of delta data reusing.
1093                  * However, we loosen this restriction when we know we
1094                  * are creating a thin pack -- it will have to be
1095                  * expanded on the other end anyway, so do not
1096                  * artificially cut the delta chain and let it go as
1097                  * deep as it wants.
1098                  */
1099                 for (i = 0, entry = objects; i < nr_objects; i++, entry++)
1100                         if (!entry->delta && entry->delta_child)
1101                                 entry->delta_limit =
1102                                         check_delta_limit(entry, 1);
1103         }
1104 }
1105
1106 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
1107
1108 static entry_sort_t current_sort;
1109
1110 static int sort_comparator(const void *_a, const void *_b)
1111 {
1112         struct object_entry *a = *(struct object_entry **)_a;
1113         struct object_entry *b = *(struct object_entry **)_b;
1114         return current_sort(a,b);
1115 }
1116
1117 static struct object_entry **create_sorted_list(entry_sort_t sort)
1118 {
1119         struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
1120         uint32_t i;
1121
1122         for (i = 0; i < nr_objects; i++)
1123                 list[i] = objects + i;
1124         current_sort = sort;
1125         qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
1126         return list;
1127 }
1128
1129 static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
1130 {
1131         return hashcmp(a->sha1, b->sha1);
1132 }
1133
1134 static struct object_entry **create_final_object_list(void)
1135 {
1136         struct object_entry **list;
1137         uint32_t i, j;
1138
1139         for (i = nr_result = 0; i < nr_objects; i++)
1140                 if (!objects[i].preferred_base)
1141                         nr_result++;
1142         list = xmalloc(nr_result * sizeof(struct object_entry *));
1143         for (i = j = 0; i < nr_objects; i++) {
1144                 if (!objects[i].preferred_base)
1145                         list[j++] = objects + i;
1146         }
1147         current_sort = sha1_sort;
1148         qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
1149         return list;
1150 }
1151
1152 static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
1153 {
1154         if (a->type < b->type)
1155                 return -1;
1156         if (a->type > b->type)
1157                 return 1;
1158         if (a->hash < b->hash)
1159                 return -1;
1160         if (a->hash > b->hash)
1161                 return 1;
1162         if (a->preferred_base < b->preferred_base)
1163                 return -1;
1164         if (a->preferred_base > b->preferred_base)
1165                 return 1;
1166         if (a->size < b->size)
1167                 return -1;
1168         if (a->size > b->size)
1169                 return 1;
1170         return a < b ? -1 : (a > b);
1171 }
1172
1173 struct unpacked {
1174         struct object_entry *entry;
1175         void *data;
1176         struct delta_index *index;
1177 };
1178
1179 /*
1180  * We search for deltas _backwards_ in a list sorted by type and
1181  * by size, so that we see progressively smaller and smaller files.
1182  * That's because we prefer deltas to be from the bigger file
1183  * to the smaller - deletes are potentially cheaper, but perhaps
1184  * more importantly, the bigger file is likely the more recent
1185  * one.
1186  */
1187 static int try_delta(struct unpacked *trg, struct unpacked *src,
1188                      unsigned max_depth)
1189 {
1190         struct object_entry *trg_entry = trg->entry;
1191         struct object_entry *src_entry = src->entry;
1192         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1193         enum object_type type;
1194         void *delta_buf;
1195
1196         /* Don't bother doing diffs between different types */
1197         if (trg_entry->type != src_entry->type)
1198                 return -1;
1199
1200         /* We do not compute delta to *create* objects we are not
1201          * going to pack.
1202          */
1203         if (trg_entry->preferred_base)
1204                 return -1;
1205
1206         /*
1207          * We do not bother to try a delta that we discarded
1208          * on an earlier try, but only when reusing delta data.
1209          */
1210         if (!no_reuse_delta && trg_entry->in_pack &&
1211             trg_entry->in_pack == src_entry->in_pack &&
1212             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1213             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1214                 return 0;
1215
1216         /*
1217          * If the current object is at pack edge, take the depth the
1218          * objects that depend on the current object into account --
1219          * otherwise they would become too deep.
1220          */
1221         if (trg_entry->delta_child) {
1222                 if (max_depth <= trg_entry->delta_limit)
1223                         return 0;
1224                 max_depth -= trg_entry->delta_limit;
1225         }
1226         if (src_entry->depth >= max_depth)
1227                 return 0;
1228
1229         /* Now some size filtering heuristics. */
1230         trg_size = trg_entry->size;
1231         max_size = trg_size/2 - 20;
1232         max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1233         if (max_size == 0)
1234                 return 0;
1235         if (trg_entry->delta && trg_entry->delta_size <= max_size)
1236                 max_size = trg_entry->delta_size-1;
1237         src_size = src_entry->size;
1238         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1239         if (sizediff >= max_size)
1240                 return 0;
1241
1242         /* Load data if not already done */
1243         if (!trg->data) {
1244                 trg->data = read_sha1_file(trg_entry->sha1, &type, &sz);
1245                 if (sz != trg_size)
1246                         die("object %s inconsistent object length (%lu vs %lu)",
1247                             sha1_to_hex(trg_entry->sha1), sz, trg_size);
1248         }
1249         if (!src->data) {
1250                 src->data = read_sha1_file(src_entry->sha1, &type, &sz);
1251                 if (sz != src_size)
1252                         die("object %s inconsistent object length (%lu vs %lu)",
1253                             sha1_to_hex(src_entry->sha1), sz, src_size);
1254         }
1255         if (!src->index) {
1256                 src->index = create_delta_index(src->data, src_size);
1257                 if (!src->index)
1258                         die("out of memory");
1259         }
1260
1261         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1262         if (!delta_buf)
1263                 return 0;
1264
1265         trg_entry->delta = src_entry;
1266         trg_entry->delta_size = delta_size;
1267         trg_entry->depth = src_entry->depth + 1;
1268         free(delta_buf);
1269         return 1;
1270 }
1271
1272 static void progress_interval(int signum)
1273 {
1274         progress_update = 1;
1275 }
1276
1277 static void find_deltas(struct object_entry **list, int window, int depth)
1278 {
1279         uint32_t i = nr_objects, idx = 0, processed = 0;
1280         unsigned int array_size = window * sizeof(struct unpacked);
1281         struct unpacked *array;
1282         unsigned last_percent = 999;
1283
1284         if (!nr_objects)
1285                 return;
1286         array = xmalloc(array_size);
1287         memset(array, 0, array_size);
1288         if (progress)
1289                 fprintf(stderr, "Deltifying %u objects.\n", nr_result);
1290
1291         do {
1292                 struct object_entry *entry = list[--i];
1293                 struct unpacked *n = array + idx;
1294                 int j;
1295
1296                 if (!entry->preferred_base)
1297                         processed++;
1298
1299                 if (progress) {
1300                         unsigned percent = processed * 100 / nr_result;
1301                         if (percent != last_percent || progress_update) {
1302                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
1303                                         percent, processed, nr_result);
1304                                 progress_update = 0;
1305                                 last_percent = percent;
1306                         }
1307                 }
1308
1309                 if (entry->delta)
1310                         /* This happens if we decided to reuse existing
1311                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1312                          */
1313                         continue;
1314
1315                 if (entry->size < 50)
1316                         continue;
1317                 free_delta_index(n->index);
1318                 n->index = NULL;
1319                 free(n->data);
1320                 n->data = NULL;
1321                 n->entry = entry;
1322
1323                 j = window;
1324                 while (--j > 0) {
1325                         uint32_t other_idx = idx + j;
1326                         struct unpacked *m;
1327                         if (other_idx >= window)
1328                                 other_idx -= window;
1329                         m = array + other_idx;
1330                         if (!m->entry)
1331                                 break;
1332                         if (try_delta(n, m, depth) < 0)
1333                                 break;
1334                 }
1335                 /* if we made n a delta, and if n is already at max
1336                  * depth, leaving it in the window is pointless.  we
1337                  * should evict it first.
1338                  */
1339                 if (entry->delta && depth <= entry->depth)
1340                         continue;
1341
1342                 idx++;
1343                 if (idx >= window)
1344                         idx = 0;
1345         } while (i > 0);
1346
1347         if (progress)
1348                 fputc('\n', stderr);
1349
1350         for (i = 0; i < window; ++i) {
1351                 free_delta_index(array[i].index);
1352                 free(array[i].data);
1353         }
1354         free(array);
1355 }
1356
1357 static void prepare_pack(int window, int depth)
1358 {
1359         get_object_details();
1360         sorted_by_type = create_sorted_list(type_size_sort);
1361         if (window && depth)
1362                 find_deltas(sorted_by_type, window+1, depth);
1363 }
1364
1365 static int reuse_cached_pack(unsigned char *sha1)
1366 {
1367         static const char cache[] = "pack-cache/pack-%s.%s";
1368         char *cached_pack, *cached_idx;
1369         int ifd, ofd, ifd_ix = -1;
1370
1371         cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
1372         ifd = open(cached_pack, O_RDONLY);
1373         if (ifd < 0)
1374                 return 0;
1375
1376         if (!pack_to_stdout) {
1377                 cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
1378                 ifd_ix = open(cached_idx, O_RDONLY);
1379                 if (ifd_ix < 0) {
1380                         close(ifd);
1381                         return 0;
1382                 }
1383         }
1384
1385         if (progress)
1386                 fprintf(stderr, "Reusing %u objects pack %s\n", nr_objects,
1387                         sha1_to_hex(sha1));
1388
1389         if (pack_to_stdout) {
1390                 if (copy_fd(ifd, 1))
1391                         exit(1);
1392                 close(ifd);
1393         }
1394         else {
1395                 char name[PATH_MAX];
1396                 snprintf(name, sizeof(name),
1397                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
1398                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1399                 if (ofd < 0)
1400                         die("unable to open %s (%s)", name, strerror(errno));
1401                 if (copy_fd(ifd, ofd))
1402                         exit(1);
1403                 close(ifd);
1404
1405                 snprintf(name, sizeof(name),
1406                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
1407                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1408                 if (ofd < 0)
1409                         die("unable to open %s (%s)", name, strerror(errno));
1410                 if (copy_fd(ifd_ix, ofd))
1411                         exit(1);
1412                 close(ifd_ix);
1413                 puts(sha1_to_hex(sha1));
1414         }
1415
1416         return 1;
1417 }
1418
1419 static void setup_progress_signal(void)
1420 {
1421         struct sigaction sa;
1422         struct itimerval v;
1423
1424         memset(&sa, 0, sizeof(sa));
1425         sa.sa_handler = progress_interval;
1426         sigemptyset(&sa.sa_mask);
1427         sa.sa_flags = SA_RESTART;
1428         sigaction(SIGALRM, &sa, NULL);
1429
1430         v.it_interval.tv_sec = 1;
1431         v.it_interval.tv_usec = 0;
1432         v.it_value = v.it_interval;
1433         setitimer(ITIMER_REAL, &v, NULL);
1434 }
1435
1436 static int git_pack_config(const char *k, const char *v)
1437 {
1438         if(!strcmp(k, "pack.window")) {
1439                 window = git_config_int(k, v);
1440                 return 0;
1441         }
1442         return git_default_config(k, v);
1443 }
1444
1445 static void read_object_list_from_stdin(void)
1446 {
1447         char line[40 + 1 + PATH_MAX + 2];
1448         unsigned char sha1[20];
1449         unsigned hash;
1450
1451         for (;;) {
1452                 if (!fgets(line, sizeof(line), stdin)) {
1453                         if (feof(stdin))
1454                                 break;
1455                         if (!ferror(stdin))
1456                                 die("fgets returned NULL, not EOF, not error!");
1457                         if (errno != EINTR)
1458                                 die("fgets: %s", strerror(errno));
1459                         clearerr(stdin);
1460                         continue;
1461                 }
1462                 if (line[0] == '-') {
1463                         if (get_sha1_hex(line+1, sha1))
1464                                 die("expected edge sha1, got garbage:\n %s",
1465                                     line);
1466                         add_preferred_base(sha1);
1467                         continue;
1468                 }
1469                 if (get_sha1_hex(line, sha1))
1470                         die("expected sha1, got garbage:\n %s", line);
1471
1472                 hash = name_hash(line+41);
1473                 add_preferred_base_object(line+41, hash);
1474                 add_object_entry(sha1, hash, 0);
1475         }
1476 }
1477
1478 static void show_commit(struct commit *commit)
1479 {
1480         unsigned hash = name_hash("");
1481         add_preferred_base_object("", hash);
1482         add_object_entry(commit->object.sha1, hash, 0);
1483 }
1484
1485 static void show_object(struct object_array_entry *p)
1486 {
1487         unsigned hash = name_hash(p->name);
1488         add_preferred_base_object(p->name, hash);
1489         add_object_entry(p->item->sha1, hash, 0);
1490 }
1491
1492 static void show_edge(struct commit *commit)
1493 {
1494         add_preferred_base(commit->object.sha1);
1495 }
1496
1497 static void get_object_list(int ac, const char **av)
1498 {
1499         struct rev_info revs;
1500         char line[1000];
1501         int flags = 0;
1502
1503         init_revisions(&revs, NULL);
1504         save_commit_buffer = 0;
1505         track_object_refs = 0;
1506         setup_revisions(ac, av, &revs, NULL);
1507
1508         while (fgets(line, sizeof(line), stdin) != NULL) {
1509                 int len = strlen(line);
1510                 if (line[len - 1] == '\n')
1511                         line[--len] = 0;
1512                 if (!len)
1513                         break;
1514                 if (*line == '-') {
1515                         if (!strcmp(line, "--not")) {
1516                                 flags ^= UNINTERESTING;
1517                                 continue;
1518                         }
1519                         die("not a rev '%s'", line);
1520                 }
1521                 if (handle_revision_arg(line, &revs, flags, 1))
1522                         die("bad revision '%s'", line);
1523         }
1524
1525         prepare_revision_walk(&revs);
1526         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1527         traverse_commit_list(&revs, show_commit, show_object);
1528 }
1529
1530 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1531 {
1532         SHA_CTX ctx;
1533         int depth = 10;
1534         struct object_entry **list;
1535         int use_internal_rev_list = 0;
1536         int thin = 0;
1537         uint32_t i;
1538         const char **rp_av;
1539         int rp_ac_alloc = 64;
1540         int rp_ac;
1541
1542         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1543
1544         rp_av[0] = "pack-objects";
1545         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1546         rp_ac = 2;
1547
1548         git_config(git_pack_config);
1549
1550         progress = isatty(2);
1551         for (i = 1; i < argc; i++) {
1552                 const char *arg = argv[i];
1553
1554                 if (*arg != '-')
1555                         break;
1556
1557                 if (!strcmp("--non-empty", arg)) {
1558                         non_empty = 1;
1559                         continue;
1560                 }
1561                 if (!strcmp("--local", arg)) {
1562                         local = 1;
1563                         continue;
1564                 }
1565                 if (!strcmp("--incremental", arg)) {
1566                         incremental = 1;
1567                         continue;
1568                 }
1569                 if (!prefixcmp(arg, "--window=")) {
1570                         char *end;
1571                         window = strtoul(arg+9, &end, 0);
1572                         if (!arg[9] || *end)
1573                                 usage(pack_usage);
1574                         continue;
1575                 }
1576                 if (!prefixcmp(arg, "--depth=")) {
1577                         char *end;
1578                         depth = strtoul(arg+8, &end, 0);
1579                         if (!arg[8] || *end)
1580                                 usage(pack_usage);
1581                         continue;
1582                 }
1583                 if (!strcmp("--progress", arg)) {
1584                         progress = 1;
1585                         continue;
1586                 }
1587                 if (!strcmp("--all-progress", arg)) {
1588                         progress = 2;
1589                         continue;
1590                 }
1591                 if (!strcmp("-q", arg)) {
1592                         progress = 0;
1593                         continue;
1594                 }
1595                 if (!strcmp("--no-reuse-delta", arg)) {
1596                         no_reuse_delta = 1;
1597                         continue;
1598                 }
1599                 if (!strcmp("--delta-base-offset", arg)) {
1600                         allow_ofs_delta = 1;
1601                         continue;
1602                 }
1603                 if (!strcmp("--stdout", arg)) {
1604                         pack_to_stdout = 1;
1605                         continue;
1606                 }
1607                 if (!strcmp("--revs", arg)) {
1608                         use_internal_rev_list = 1;
1609                         continue;
1610                 }
1611                 if (!strcmp("--unpacked", arg) ||
1612                     !prefixcmp(arg, "--unpacked=") ||
1613                     !strcmp("--reflog", arg) ||
1614                     !strcmp("--all", arg)) {
1615                         use_internal_rev_list = 1;
1616                         if (rp_ac >= rp_ac_alloc - 1) {
1617                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
1618                                 rp_av = xrealloc(rp_av,
1619                                                  rp_ac_alloc * sizeof(*rp_av));
1620                         }
1621                         rp_av[rp_ac++] = arg;
1622                         continue;
1623                 }
1624                 if (!strcmp("--thin", arg)) {
1625                         use_internal_rev_list = 1;
1626                         thin = 1;
1627                         rp_av[1] = "--objects-edge";
1628                         continue;
1629                 }
1630                 usage(pack_usage);
1631         }
1632
1633         /* Traditionally "pack-objects [options] base extra" failed;
1634          * we would however want to take refs parameter that would
1635          * have been given to upstream rev-list ourselves, which means
1636          * we somehow want to say what the base name is.  So the
1637          * syntax would be:
1638          *
1639          * pack-objects [options] base <refs...>
1640          *
1641          * in other words, we would treat the first non-option as the
1642          * base_name and send everything else to the internal revision
1643          * walker.
1644          */
1645
1646         if (!pack_to_stdout)
1647                 base_name = argv[i++];
1648
1649         if (pack_to_stdout != !base_name)
1650                 usage(pack_usage);
1651
1652         if (!pack_to_stdout && thin)
1653                 die("--thin cannot be used to build an indexable pack.");
1654
1655         prepare_packed_git();
1656
1657         if (progress) {
1658                 fprintf(stderr, "Generating pack...\n");
1659                 setup_progress_signal();
1660         }
1661
1662         if (!use_internal_rev_list)
1663                 read_object_list_from_stdin();
1664         else {
1665                 rp_av[rp_ac] = NULL;
1666                 get_object_list(rp_ac, rp_av);
1667         }
1668
1669         if (progress)
1670                 fprintf(stderr, "Done counting %u objects.\n", nr_objects);
1671         sorted_by_sha = create_final_object_list();
1672         if (non_empty && !nr_result)
1673                 return 0;
1674
1675         SHA1_Init(&ctx);
1676         list = sorted_by_sha;
1677         for (i = 0; i < nr_result; i++) {
1678                 struct object_entry *entry = *list++;
1679                 SHA1_Update(&ctx, entry->sha1, 20);
1680         }
1681         SHA1_Final(object_list_sha1, &ctx);
1682         if (progress && (nr_objects != nr_result))
1683                 fprintf(stderr, "Result has %u objects.\n", nr_result);
1684
1685         if (reuse_cached_pack(object_list_sha1))
1686                 ;
1687         else {
1688                 if (nr_result)
1689                         prepare_pack(window, depth);
1690                 if (progress == 1 && pack_to_stdout) {
1691                         /* the other end usually displays progress itself */
1692                         struct itimerval v = {{0,},};
1693                         setitimer(ITIMER_REAL, &v, NULL);
1694                         signal(SIGALRM, SIG_IGN );
1695                         progress_update = 0;
1696                 }
1697                 write_pack_file();
1698                 if (!pack_to_stdout) {
1699                         write_index_file();
1700                         puts(sha1_to_hex(object_list_sha1));
1701                 }
1702         }
1703         if (progress)
1704                 fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
1705                         written, written_delta, reused, reused_delta);
1706         return 0;
1707 }