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

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "attr.h"
   4 #include "object.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "delta.h"
  10 #include "pack.h"
  11 #include "pack-revindex.h"
  12 #include "csum-file.h"
  13 #include "tree-walk.h"
  14 #include "diff.h"
  15 #include "revision.h"
  16 #include "list-objects.h"
  17 #include "pack-objects.h"
  18 #include "progress.h"
  19 #include "refs.h"
  20 #include "streaming.h"
  21 #include "thread-utils.h"
  22 #include "pack-bitmap.h"
  23 #include "reachable.h"
  24 #include "sha1-array.h"
  25 #include "argv-array.h"
  26
  27 static const char *pack_usage[] = {
  28         N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
  29         N_("git pack-objects [<options>...] <base-name> [< <ref-list> | < <object-list>]"),
  30         NULL
  31 };
  32
  33 /*
  34  * Objects we are going to pack are collected in the `to_pack` structure.
  35  * It contains an array (dynamically expanded) of the object data, and a map
  36  * that can resolve SHA1s to their position in the array.
  37  */
  38 static struct packing_data to_pack;
  39
  40 static struct pack_idx_entry **written_list;
  41 static uint32_t nr_result, nr_written;
  42
  43 static int non_empty;
  44 static int reuse_delta = 1, reuse_object = 1;
  45 static int keep_unreachable, unpack_unreachable, include_tag;
  46 static unsigned long unpack_unreachable_expiration;
  47 static int local;
  48 static int incremental;
  49 static int ignore_packed_keep;
  50 static int allow_ofs_delta;
  51 static struct pack_idx_option pack_idx_opts;
  52 static const char *base_name;
  53 static int progress = 1;
  54 static int window = 10;
  55 static unsigned long pack_size_limit;
  56 static int depth = 50;
  57 static int delta_search_threads;
  58 static int pack_to_stdout;
  59 static int num_preferred_base;
  60 static struct progress *progress_state;
  61 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  62 static int pack_compression_seen;
  63
  64 static struct packed_git *reuse_packfile;
  65 static uint32_t reuse_packfile_objects;
  66 static off_t reuse_packfile_offset;
  67
  68 static int use_bitmap_index = 1;
  69 static int write_bitmap_index;
  70 static uint16_t write_bitmap_options;
  71
  72 static unsigned long delta_cache_size = 0;
  73 static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  74 static unsigned long cache_max_small_delta_size = 1000;
  75
  76 static unsigned long window_memory_limit = 0;
  77
  78 /*
  79  * stats
  80  */
  81 static uint32_t written, written_delta;
  82 static uint32_t reused, reused_delta;
  83
  84 /*
  85  * Indexed commits
  86  */
  87 static struct commit **indexed_commits;
  88 static unsigned int indexed_commits_nr;
  89 static unsigned int indexed_commits_alloc;
  90
  91 static void index_commit_for_bitmap(struct commit *commit)
  92 {
  93         if (indexed_commits_nr >= indexed_commits_alloc) {
  94                 indexed_commits_alloc = (indexed_commits_alloc + 32) * 2;
  95                 REALLOC_ARRAY(indexed_commits, indexed_commits_alloc);
  96         }
  97
  98         indexed_commits[indexed_commits_nr++] = commit;
  99 }
 100
 101 static void *get_delta(struct object_entry *entry)
 102 {
 103         unsigned long size, base_size, delta_size;
 104         void *buf, *base_buf, *delta_buf;
 105         enum object_type type;
 106
 107         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 108         if (!buf)
 109                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 110         base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
 111         if (!base_buf)
 112                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 113         delta_buf = diff_delta(base_buf, base_size,
 114                                buf, size, &delta_size, 0);
 115         if (!delta_buf || delta_size != entry->delta_size)
 116                 die("delta size changed");
 117         free(buf);
 118         free(base_buf);
 119         return delta_buf;
 120 }
 121
 122 static unsigned long do_compress(void **pptr, unsigned long size)
 123 {
 124         git_zstream stream;
 125         void *in, *out;
 126         unsigned long maxsize;
 127
 128         git_deflate_init(&stream, pack_compression_level);
 129         maxsize = git_deflate_bound(&stream, size);
 130
 131         in = *pptr;
 132         out = xmalloc(maxsize);
 133         *pptr = out;
 134
 135         stream.next_in = in;
 136         stream.avail_in = size;
 137         stream.next_out = out;
 138         stream.avail_out = maxsize;
 139         while (git_deflate(&stream, Z_FINISH) == Z_OK)
 140                 ; /* nothing */
 141         git_deflate_end(&stream);
 142
 143         free(in);
 144         return stream.total_out;
 145 }
 146
 147 static unsigned long write_large_blob_data(struct git_istream *st, struct sha1file *f,
 148                                            const unsigned char *sha1)
 149 {
 150         git_zstream stream;
 151         unsigned char ibuf[1024 * 16];
 152         unsigned char obuf[1024 * 16];
 153         unsigned long olen = 0;
 154
 155         git_deflate_init(&stream, pack_compression_level);
 156
 157         for (;;) {
 158                 ssize_t readlen;
 159                 int zret = Z_OK;
 160                 readlen = read_istream(st, ibuf, sizeof(ibuf));
 161                 if (readlen == -1)
 162                         die(_("unable to read %s"), sha1_to_hex(sha1));
 163
 164                 stream.next_in = ibuf;
 165                 stream.avail_in = readlen;
 166                 while ((stream.avail_in || readlen == 0) &&
 167                        (zret == Z_OK || zret == Z_BUF_ERROR)) {
 168                         stream.next_out = obuf;
 169                         stream.avail_out = sizeof(obuf);
 170                         zret = git_deflate(&stream, readlen ? 0 : Z_FINISH);
 171                         sha1write(f, obuf, stream.next_out - obuf);
 172                         olen += stream.next_out - obuf;
 173                 }
 174                 if (stream.avail_in)
 175                         die(_("deflate error (%d)"), zret);
 176                 if (readlen == 0) {
 177                         if (zret != Z_STREAM_END)
 178                                 die(_("deflate error (%d)"), zret);
 179                         break;
 180                 }
 181         }
 182         git_deflate_end(&stream);
 183         return olen;
 184 }
 185
 186 /*
 187  * we are going to reuse the existing object data as is.  make
 188  * sure it is not corrupt.
 189  */
 190 static int check_pack_inflate(struct packed_git *p,
 191                 struct pack_window **w_curs,
 192                 off_t offset,
 193                 off_t len,
 194                 unsigned long expect)
 195 {
 196         git_zstream stream;
 197         unsigned char fakebuf[4096], *in;
 198         int st;
 199
 200         memset(&stream, 0, sizeof(stream));
 201         git_inflate_init(&stream);
 202         do {
 203                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 204                 stream.next_in = in;
 205                 stream.next_out = fakebuf;
 206                 stream.avail_out = sizeof(fakebuf);
 207                 st = git_inflate(&stream, Z_FINISH);
 208                 offset += stream.next_in - in;
 209         } while (st == Z_OK || st == Z_BUF_ERROR);
 210         git_inflate_end(&stream);
 211         return (st == Z_STREAM_END &&
 212                 stream.total_out == expect &&
 213                 stream.total_in == len) ? 0 : -1;
 214 }
 215
 216 static void copy_pack_data(struct sha1file *f,
 217                 struct packed_git *p,
 218                 struct pack_window **w_curs,
 219                 off_t offset,
 220                 off_t len)
 221 {
 222         unsigned char *in;
 223         unsigned long avail;
 224
 225         while (len) {
 226                 in = use_pack(p, w_curs, offset, &avail);
 227                 if (avail > len)
 228                         avail = (unsigned long)len;
 229                 sha1write(f, in, avail);
 230                 offset += avail;
 231                 len -= avail;
 232         }
 233 }
 234
 235 /* Return 0 if we will bust the pack-size limit */
 236 static unsigned long write_no_reuse_object(struct sha1file *f, struct object_entry *entry,
 237                                            unsigned long limit, int usable_delta)
 238 {
 239         unsigned long size, datalen;
 240         unsigned char header[10], dheader[10];
 241         unsigned hdrlen;
 242         enum object_type type;
 243         void *buf;
 244         struct git_istream *st = NULL;
 245
 246         if (!usable_delta) {
 247                 if (entry->type == OBJ_BLOB &&
 248                     entry->size > big_file_threshold &&
 249                     (st = open_istream(entry->idx.sha1, &type, &size, NULL)) != NULL)
 250                         buf = NULL;
 251                 else {
 252                         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 253                         if (!buf)
 254                                 die(_("unable to read %s"), sha1_to_hex(entry->idx.sha1));
 255                 }
 256                 /*
 257                  * make sure no cached delta data remains from a
 258                  * previous attempt before a pack split occurred.
 259                  */
 260                 free(entry->delta_data);
 261                 entry->delta_data = NULL;
 262                 entry->z_delta_size = 0;
 263         } else if (entry->delta_data) {
 264                 size = entry->delta_size;
 265                 buf = entry->delta_data;
 266                 entry->delta_data = NULL;
 267                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 268                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 269         } else {
 270                 buf = get_delta(entry);
 271                 size = entry->delta_size;
 272                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 273                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 274         }
 275
 276         if (st) /* large blob case, just assume we don't compress well */
 277                 datalen = size;
 278         else if (entry->z_delta_size)
 279                 datalen = entry->z_delta_size;
 280         else
 281                 datalen = do_compress(&buf, size);
 282
 283         /*
 284          * The object header is a byte of 'type' followed by zero or
 285          * more bytes of length.
 286          */
 287         hdrlen = encode_in_pack_object_header(type, size, header);
 288
 289         if (type == OBJ_OFS_DELTA) {
 290                 /*
 291                  * Deltas with relative base contain an additional
 292                  * encoding of the relative offset for the delta
 293                  * base from this object's position in the pack.
 294                  */
 295                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 296                 unsigned pos = sizeof(dheader) - 1;
 297                 dheader[pos] = ofs & 127;
 298                 while (ofs >>= 7)
 299                         dheader[--pos] = 128 | (--ofs & 127);
 300                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 301                         if (st)
 302                                 close_istream(st);
 303                         free(buf);
 304                         return 0;
 305                 }
 306                 sha1write(f, header, hdrlen);
 307                 sha1write(f, dheader + pos, sizeof(dheader) - pos);
 308                 hdrlen += sizeof(dheader) - pos;
 309         } else if (type == OBJ_REF_DELTA) {
 310                 /*
 311                  * Deltas with a base reference contain
 312                  * an additional 20 bytes for the base sha1.
 313                  */
 314                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 315                         if (st)
 316                                 close_istream(st);
 317                         free(buf);
 318                         return 0;
 319                 }
 320                 sha1write(f, header, hdrlen);
 321                 sha1write(f, entry->delta->idx.sha1, 20);
 322                 hdrlen += 20;
 323         } else {
 324                 if (limit && hdrlen + datalen + 20 >= limit) {
 325                         if (st)
 326                                 close_istream(st);
 327                         free(buf);
 328                         return 0;
 329                 }
 330                 sha1write(f, header, hdrlen);
 331         }
 332         if (st) {
 333                 datalen = write_large_blob_data(st, f, entry->idx.sha1);
 334                 close_istream(st);
 335         } else {
 336                 sha1write(f, buf, datalen);
 337                 free(buf);
 338         }
 339
 340         return hdrlen + datalen;
 341 }
 342
 343 /* Return 0 if we will bust the pack-size limit */
 344 static unsigned long write_reuse_object(struct sha1file *f, struct object_entry *entry,
 345                                         unsigned long limit, int usable_delta)
 346 {
 347         struct packed_git *p = entry->in_pack;
 348         struct pack_window *w_curs = NULL;
 349         struct revindex_entry *revidx;
 350         off_t offset;
 351         enum object_type type = entry->type;
 352         unsigned long datalen;
 353         unsigned char header[10], dheader[10];
 354         unsigned hdrlen;
 355
 356         if (entry->delta)
 357                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 358                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 359         hdrlen = encode_in_pack_object_header(type, entry->size, header);
 360
 361         offset = entry->in_pack_offset;
 362         revidx = find_pack_revindex(p, offset);
 363         datalen = revidx[1].offset - offset;
 364         if (!pack_to_stdout && p->index_version > 1 &&
 365             check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 366                 error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 367                 unuse_pack(&w_curs);
 368                 return write_no_reuse_object(f, entry, limit, usable_delta);
 369         }
 370
 371         offset += entry->in_pack_header_size;
 372         datalen -= entry->in_pack_header_size;
 373
 374         if (!pack_to_stdout && p->index_version == 1 &&
 375             check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 376                 error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 377                 unuse_pack(&w_curs);
 378                 return write_no_reuse_object(f, entry, limit, usable_delta);
 379         }
 380
 381         if (type == OBJ_OFS_DELTA) {
 382                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 383                 unsigned pos = sizeof(dheader) - 1;
 384                 dheader[pos] = ofs & 127;
 385                 while (ofs >>= 7)
 386                         dheader[--pos] = 128 | (--ofs & 127);
 387                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 388                         unuse_pack(&w_curs);
 389                         return 0;
 390                 }
 391                 sha1write(f, header, hdrlen);
 392                 sha1write(f, dheader + pos, sizeof(dheader) - pos);
 393                 hdrlen += sizeof(dheader) - pos;
 394                 reused_delta++;
 395         } else if (type == OBJ_REF_DELTA) {
 396                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 397                         unuse_pack(&w_curs);
 398                         return 0;
 399                 }
 400                 sha1write(f, header, hdrlen);
 401                 sha1write(f, entry->delta->idx.sha1, 20);
 402                 hdrlen += 20;
 403                 reused_delta++;
 404         } else {
 405                 if (limit && hdrlen + datalen + 20 >= limit) {
 406                         unuse_pack(&w_curs);
 407                         return 0;
 408                 }
 409                 sha1write(f, header, hdrlen);
 410         }
 411         copy_pack_data(f, p, &w_curs, offset, datalen);
 412         unuse_pack(&w_curs);
 413         reused++;
 414         return hdrlen + datalen;
 415 }
 416
 417 /* Return 0 if we will bust the pack-size limit */
 418 static unsigned long write_object(struct sha1file *f,
 419                                   struct object_entry *entry,
 420                                   off_t write_offset)
 421 {
 422         unsigned long limit, len;
 423         int usable_delta, to_reuse;
 424
 425         if (!pack_to_stdout)
 426                 crc32_begin(f);
 427
 428         /* apply size limit if limited packsize and not first object */
 429         if (!pack_size_limit || !nr_written)
 430                 limit = 0;
 431         else if (pack_size_limit <= write_offset)
 432                 /*
 433                  * the earlier object did not fit the limit; avoid
 434                  * mistaking this with unlimited (i.e. limit = 0).
 435                  */
 436                 limit = 1;
 437         else
 438                 limit = pack_size_limit - write_offset;
 439
 440         if (!entry->delta)
 441                 usable_delta = 0;       /* no delta */
 442         else if (!pack_size_limit)
 443                usable_delta = 1;        /* unlimited packfile */
 444         else if (entry->delta->idx.offset == (off_t)-1)
 445                 usable_delta = 0;       /* base was written to another pack */
 446         else if (entry->delta->idx.offset)
 447                 usable_delta = 1;       /* base already exists in this pack */
 448         else
 449                 usable_delta = 0;       /* base could end up in another pack */
 450
 451         if (!reuse_object)
 452                 to_reuse = 0;   /* explicit */
 453         else if (!entry->in_pack)
 454                 to_reuse = 0;   /* can't reuse what we don't have */
 455         else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
 456                                 /* check_object() decided it for us ... */
 457                 to_reuse = usable_delta;
 458                                 /* ... but pack split may override that */
 459         else if (entry->type != entry->in_pack_type)
 460                 to_reuse = 0;   /* pack has delta which is unusable */
 461         else if (entry->delta)
 462                 to_reuse = 0;   /* we want to pack afresh */
 463         else
 464                 to_reuse = 1;   /* we have it in-pack undeltified,
 465                                  * and we do not need to deltify it.
 466                                  */
 467
 468         if (!to_reuse)
 469                 len = write_no_reuse_object(f, entry, limit, usable_delta);
 470         else
 471                 len = write_reuse_object(f, entry, limit, usable_delta);
 472         if (!len)
 473                 return 0;
 474
 475         if (usable_delta)
 476                 written_delta++;
 477         written++;
 478         if (!pack_to_stdout)
 479                 entry->idx.crc32 = crc32_end(f);
 480         return len;
 481 }
 482
 483 enum write_one_status {
 484         WRITE_ONE_SKIP = -1, /* already written */
 485         WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 486         WRITE_ONE_WRITTEN = 1, /* normal */
 487         WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 488 };
 489
 490 static enum write_one_status write_one(struct sha1file *f,
 491                                        struct object_entry *e,
 492                                        off_t *offset)
 493 {
 494         unsigned long size;
 495         int recursing;
 496
 497         /*
 498          * we set offset to 1 (which is an impossible value) to mark
 499          * the fact that this object is involved in "write its base
 500          * first before writing a deltified object" recursion.
 501          */
 502         recursing = (e->idx.offset == 1);
 503         if (recursing) {
 504                 warning("recursive delta detected for object %s",
 505                         sha1_to_hex(e->idx.sha1));
 506                 return WRITE_ONE_RECURSIVE;
 507         } else if (e->idx.offset || e->preferred_base) {
 508                 /* offset is non zero if object is written already. */
 509                 return WRITE_ONE_SKIP;
 510         }
 511
 512         /* if we are deltified, write out base object first. */
 513         if (e->delta) {
 514                 e->idx.offset = 1; /* now recurse */
 515                 switch (write_one(f, e->delta, offset)) {
 516                 case WRITE_ONE_RECURSIVE:
 517                         /* we cannot depend on this one */
 518                         e->delta = NULL;
 519                         break;
 520                 default:
 521                         break;
 522                 case WRITE_ONE_BREAK:
 523                         e->idx.offset = recursing;
 524                         return WRITE_ONE_BREAK;
 525                 }
 526         }
 527
 528         e->idx.offset = *offset;
 529         size = write_object(f, e, *offset);
 530         if (!size) {
 531                 e->idx.offset = recursing;
 532                 return WRITE_ONE_BREAK;
 533         }
 534         written_list[nr_written++] = &e->idx;
 535
 536         /* make sure off_t is sufficiently large not to wrap */
 537         if (signed_add_overflows(*offset, size))
 538                 die("pack too large for current definition of off_t");
 539         *offset += size;
 540         return WRITE_ONE_WRITTEN;
 541 }
 542
 543 static int mark_tagged(const char *path, const struct object_id *oid, int flag,
 544                        void *cb_data)
 545 {
 546         unsigned char peeled[20];
 547         struct object_entry *entry = packlist_find(&to_pack, oid->hash, NULL);
 548
 549         if (entry)
 550                 entry->tagged = 1;
 551         if (!peel_ref(path, peeled)) {
 552                 entry = packlist_find(&to_pack, peeled, NULL);
 553                 if (entry)
 554                         entry->tagged = 1;
 555         }
 556         return 0;
 557 }
 558
 559 static inline void add_to_write_order(struct object_entry **wo,
 560                                unsigned int *endp,
 561                                struct object_entry *e)
 562 {
 563         if (e->filled)
 564                 return;
 565         wo[(*endp)++] = e;
 566         e->filled = 1;
 567 }
 568
 569 static void add_descendants_to_write_order(struct object_entry **wo,
 570                                            unsigned int *endp,
 571                                            struct object_entry *e)
 572 {
 573         int add_to_order = 1;
 574         while (e) {
 575                 if (add_to_order) {
 576                         struct object_entry *s;
 577                         /* add this node... */
 578                         add_to_write_order(wo, endp, e);
 579                         /* all its siblings... */
 580                         for (s = e->delta_sibling; s; s = s->delta_sibling) {
 581                                 add_to_write_order(wo, endp, s);
 582                         }
 583                 }
 584                 /* drop down a level to add left subtree nodes if possible */
 585                 if (e->delta_child) {
 586                         add_to_order = 1;
 587                         e = e->delta_child;
 588                 } else {
 589                         add_to_order = 0;
 590                         /* our sibling might have some children, it is next */
 591                         if (e->delta_sibling) {
 592                                 e = e->delta_sibling;
 593                                 continue;
 594                         }
 595                         /* go back to our parent node */
 596                         e = e->delta;
 597                         while (e && !e->delta_sibling) {
 598                                 /* we're on the right side of a subtree, keep
 599                                  * going up until we can go right again */
 600                                 e = e->delta;
 601                         }
 602                         if (!e) {
 603                                 /* done- we hit our original root node */
 604                                 return;
 605                         }
 606                         /* pass it off to sibling at this level */
 607                         e = e->delta_sibling;
 608                 }
 609         };
 610 }
 611
 612 static void add_family_to_write_order(struct object_entry **wo,
 613                                       unsigned int *endp,
 614                                       struct object_entry *e)
 615 {
 616         struct object_entry *root;
 617
 618         for (root = e; root->delta; root = root->delta)
 619                 ; /* nothing */
 620         add_descendants_to_write_order(wo, endp, root);
 621 }
 622
 623 static struct object_entry **compute_write_order(void)
 624 {
 625         unsigned int i, wo_end, last_untagged;
 626
 627         struct object_entry **wo;
 628         struct object_entry *objects = to_pack.objects;
 629
 630         for (i = 0; i < to_pack.nr_objects; i++) {
 631                 objects[i].tagged = 0;
 632                 objects[i].filled = 0;
 633                 objects[i].delta_child = NULL;
 634                 objects[i].delta_sibling = NULL;
 635         }
 636
 637         /*
 638          * Fully connect delta_child/delta_sibling network.
 639          * Make sure delta_sibling is sorted in the original
 640          * recency order.
 641          */
 642         for (i = to_pack.nr_objects; i > 0;) {
 643                 struct object_entry *e = &objects[--i];
 644                 if (!e->delta)
 645                         continue;
 646                 /* Mark me as the first child */
 647                 e->delta_sibling = e->delta->delta_child;
 648                 e->delta->delta_child = e;
 649         }
 650
 651         /*
 652          * Mark objects that are at the tip of tags.
 653          */
 654         for_each_tag_ref(mark_tagged, NULL);
 655
 656         /*
 657          * Give the objects in the original recency order until
 658          * we see a tagged tip.
 659          */
 660         ALLOC_ARRAY(wo, to_pack.nr_objects);
 661         for (i = wo_end = 0; i < to_pack.nr_objects; i++) {
 662                 if (objects[i].tagged)
 663                         break;
 664                 add_to_write_order(wo, &wo_end, &objects[i]);
 665         }
 666         last_untagged = i;
 667
 668         /*
 669          * Then fill all the tagged tips.
 670          */
 671         for (; i < to_pack.nr_objects; i++) {
 672                 if (objects[i].tagged)
 673                         add_to_write_order(wo, &wo_end, &objects[i]);
 674         }
 675
 676         /*
 677          * And then all remaining commits and tags.
 678          */
 679         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 680                 if (objects[i].type != OBJ_COMMIT &&
 681                     objects[i].type != OBJ_TAG)
 682                         continue;
 683                 add_to_write_order(wo, &wo_end, &objects[i]);
 684         }
 685
 686         /*
 687          * And then all the trees.
 688          */
 689         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 690                 if (objects[i].type != OBJ_TREE)
 691                         continue;
 692                 add_to_write_order(wo, &wo_end, &objects[i]);
 693         }
 694
 695         /*
 696          * Finally all the rest in really tight order
 697          */
 698         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 699                 if (!objects[i].filled)
 700                         add_family_to_write_order(wo, &wo_end, &objects[i]);
 701         }
 702
 703         if (wo_end != to_pack.nr_objects)
 704                 die("ordered %u objects, expected %"PRIu32, wo_end, to_pack.nr_objects);
 705
 706         return wo;
 707 }
 708
 709 static off_t write_reused_pack(struct sha1file *f)
 710 {
 711         unsigned char buffer[8192];
 712         off_t to_write, total;
 713         int fd;
 714
 715         if (!is_pack_valid(reuse_packfile))
 716                 die("packfile is invalid: %s", reuse_packfile->pack_name);
 717
 718         fd = git_open_noatime(reuse_packfile->pack_name);
 719         if (fd < 0)
 720                 die_errno("unable to open packfile for reuse: %s",
 721                           reuse_packfile->pack_name);
 722
 723         if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
 724                 die_errno("unable to seek in reused packfile");
 725
 726         if (reuse_packfile_offset < 0)
 727                 reuse_packfile_offset = reuse_packfile->pack_size - 20;
 728
 729         total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 730
 731         while (to_write) {
 732                 int read_pack = xread(fd, buffer, sizeof(buffer));
 733
 734                 if (read_pack <= 0)
 735                         die_errno("unable to read from reused packfile");
 736
 737                 if (read_pack > to_write)
 738                         read_pack = to_write;
 739
 740                 sha1write(f, buffer, read_pack);
 741                 to_write -= read_pack;
 742
 743                 /*
 744                  * We don't know the actual number of objects written,
 745                  * only how many bytes written, how many bytes total, and
 746                  * how many objects total. So we can fake it by pretending all
 747                  * objects we are writing are the same size. This gives us a
 748                  * smooth progress meter, and at the end it matches the true
 749                  * answer.
 750                  */
 751                 written = reuse_packfile_objects *
 752                                 (((double)(total - to_write)) / total);
 753                 display_progress(progress_state, written);
 754         }
 755
 756         close(fd);
 757         written = reuse_packfile_objects;
 758         display_progress(progress_state, written);
 759         return reuse_packfile_offset - sizeof(struct pack_header);
 760 }
 761
 762 static const char no_split_warning[] = N_(
 763 "disabling bitmap writing, packs are split due to pack.packSizeLimit"
 764 );
 765
 766 static void write_pack_file(void)
 767 {
 768         uint32_t i = 0, j;
 769         struct sha1file *f;
 770         off_t offset;
 771         uint32_t nr_remaining = nr_result;
 772         time_t last_mtime = 0;
 773         struct object_entry **write_order;
 774
 775         if (progress > pack_to_stdout)
 776                 progress_state = start_progress(_("Writing objects"), nr_result);
 777         ALLOC_ARRAY(written_list, to_pack.nr_objects);
 778         write_order = compute_write_order();
 779
 780         do {
 781                 unsigned char sha1[20];
 782                 char *pack_tmp_name = NULL;
 783
 784                 if (pack_to_stdout)
 785                         f = sha1fd_throughput(1, "<stdout>", progress_state);
 786                 else
 787                         f = create_tmp_packfile(&pack_tmp_name);
 788
 789                 offset = write_pack_header(f, nr_remaining);
 790
 791                 if (reuse_packfile) {
 792                         off_t packfile_size;
 793                         assert(pack_to_stdout);
 794
 795                         packfile_size = write_reused_pack(f);
 796                         offset += packfile_size;
 797                 }
 798
 799                 nr_written = 0;
 800                 for (; i < to_pack.nr_objects; i++) {
 801                         struct object_entry *e = write_order[i];
 802                         if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 803                                 break;
 804                         display_progress(progress_state, written);
 805                 }
 806
 807                 /*
 808                  * Did we write the wrong # entries in the header?
 809                  * If so, rewrite it like in fast-import
 810                  */
 811                 if (pack_to_stdout) {
 812                         sha1close(f, sha1, CSUM_CLOSE);
 813                 } else if (nr_written == nr_remaining) {
 814                         sha1close(f, sha1, CSUM_FSYNC);
 815                 } else {
 816                         int fd = sha1close(f, sha1, 0);
 817                         fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 818                                                  nr_written, sha1, offset);
 819                         close(fd);
 820                         if (write_bitmap_index) {
 821                                 warning(_(no_split_warning));
 822                                 write_bitmap_index = 0;
 823                         }
 824                 }
 825
 826                 if (!pack_to_stdout) {
 827                         struct stat st;
 828                         struct strbuf tmpname = STRBUF_INIT;
 829
 830                         /*
 831                          * Packs are runtime accessed in their mtime
 832                          * order since newer packs are more likely to contain
 833                          * younger objects.  So if we are creating multiple
 834                          * packs then we should modify the mtime of later ones
 835                          * to preserve this property.
 836                          */
 837                         if (stat(pack_tmp_name, &st) < 0) {
 838                                 warning("failed to stat %s: %s",
 839                                         pack_tmp_name, strerror(errno));
 840                         } else if (!last_mtime) {
 841                                 last_mtime = st.st_mtime;
 842                         } else {
 843                                 struct utimbuf utb;
 844                                 utb.actime = st.st_atime;
 845                                 utb.modtime = --last_mtime;
 846                                 if (utime(pack_tmp_name, &utb) < 0)
 847                                         warning("failed utime() on %s: %s",
 848                                                 pack_tmp_name, strerror(errno));
 849                         }
 850
 851                         strbuf_addf(&tmpname, "%s-", base_name);
 852
 853                         if (write_bitmap_index) {
 854                                 bitmap_writer_set_checksum(sha1);
 855                                 bitmap_writer_build_type_index(written_list, nr_written);
 856                         }
 857
 858                         finish_tmp_packfile(&tmpname, pack_tmp_name,
 859                                             written_list, nr_written,
 860                                             &pack_idx_opts, sha1);
 861
 862                         if (write_bitmap_index) {
 863                                 strbuf_addf(&tmpname, "%s.bitmap", sha1_to_hex(sha1));
 864
 865                                 stop_progress(&progress_state);
 866
 867                                 bitmap_writer_show_progress(progress);
 868                                 bitmap_writer_reuse_bitmaps(&to_pack);
 869                                 bitmap_writer_select_commits(indexed_commits, indexed_commits_nr, -1);
 870                                 bitmap_writer_build(&to_pack);
 871                                 bitmap_writer_finish(written_list, nr_written,
 872                                                      tmpname.buf, write_bitmap_options);
 873                                 write_bitmap_index = 0;
 874                         }
 875
 876                         strbuf_release(&tmpname);
 877                         free(pack_tmp_name);
 878                         puts(sha1_to_hex(sha1));
 879                 }
 880
 881                 /* mark written objects as written to previous pack */
 882                 for (j = 0; j < nr_written; j++) {
 883                         written_list[j]->offset = (off_t)-1;
 884                 }
 885                 nr_remaining -= nr_written;
 886         } while (nr_remaining && i < to_pack.nr_objects);
 887
 888         free(written_list);
 889         free(write_order);
 890         stop_progress(&progress_state);
 891         if (written != nr_result)
 892                 die("wrote %"PRIu32" objects while expecting %"PRIu32,
 893                         written, nr_result);
 894 }
 895
 896 static void setup_delta_attr_check(struct git_attr_check *check)
 897 {
 898         static struct git_attr *attr_delta;
 899
 900         if (!attr_delta)
 901                 attr_delta = git_attr("delta");
 902
 903         check[0].attr = attr_delta;
 904 }
 905
 906 static int no_try_delta(const char *path)
 907 {
 908         struct git_attr_check check[1];
 909
 910         setup_delta_attr_check(check);
 911         if (git_check_attr(path, ARRAY_SIZE(check), check))
 912                 return 0;
 913         if (ATTR_FALSE(check->value))
 914                 return 1;
 915         return 0;
 916 }
 917
 918 /*
 919  * When adding an object, check whether we have already added it
 920  * to our packing list. If so, we can skip. However, if we are
 921  * being asked to excludei t, but the previous mention was to include
 922  * it, make sure to adjust its flags and tweak our numbers accordingly.
 923  *
 924  * As an optimization, we pass out the index position where we would have
 925  * found the item, since that saves us from having to look it up again a
 926  * few lines later when we want to add the new entry.
 927  */
 928 static int have_duplicate_entry(const unsigned char *sha1,
 929                                 int exclude,
 930                                 uint32_t *index_pos)
 931 {
 932         struct object_entry *entry;
 933
 934         entry = packlist_find(&to_pack, sha1, index_pos);
 935         if (!entry)
 936                 return 0;
 937
 938         if (exclude) {
 939                 if (!entry->preferred_base)
 940                         nr_result--;
 941                 entry->preferred_base = 1;
 942         }
 943
 944         return 1;
 945 }
 946
 947 /*
 948  * Check whether we want the object in the pack (e.g., we do not want
 949  * objects found in non-local stores if the "--local" option was used).
 950  *
 951  * As a side effect of this check, we will find the packed version of this
 952  * object, if any. We therefore pass out the pack information to avoid having
 953  * to look it up again later.
 954  */
 955 static int want_object_in_pack(const unsigned char *sha1,
 956                                int exclude,
 957                                struct packed_git **found_pack,
 958                                off_t *found_offset)
 959 {
 960         struct packed_git *p;
 961
 962         if (!exclude && local && has_loose_object_nonlocal(sha1))
 963                 return 0;
 964
 965         *found_pack = NULL;
 966         *found_offset = 0;
 967
 968         for (p = packed_git; p; p = p->next) {
 969                 off_t offset = find_pack_entry_one(sha1, p);
 970                 if (offset) {
 971                         if (!*found_pack) {
 972                                 if (!is_pack_valid(p))
 973                                         continue;
 974                                 *found_offset = offset;
 975                                 *found_pack = p;
 976                         }
 977                         if (exclude)
 978                                 return 1;
 979                         if (incremental)
 980                                 return 0;
 981                         if (local && !p->pack_local)
 982                                 return 0;
 983                         if (ignore_packed_keep && p->pack_local && p->pack_keep)
 984                                 return 0;
 985                 }
 986         }
 987
 988         return 1;
 989 }
 990
 991 static void create_object_entry(const unsigned char *sha1,
 992                                 enum object_type type,
 993                                 uint32_t hash,
 994                                 int exclude,
 995                                 int no_try_delta,
 996                                 uint32_t index_pos,
 997                                 struct packed_git *found_pack,
 998                                 off_t found_offset)
 999 {
1000         struct object_entry *entry;
1001
1002         entry = packlist_alloc(&to_pack, sha1, index_pos);
1003         entry->hash = hash;
1004         if (type)
1005                 entry->type = type;
1006         if (exclude)
1007                 entry->preferred_base = 1;
1008         else
1009                 nr_result++;
1010         if (found_pack) {
1011                 entry->in_pack = found_pack;
1012                 entry->in_pack_offset = found_offset;
1013         }
1014
1015         entry->no_try_delta = no_try_delta;
1016 }
1017
1018 static const char no_closure_warning[] = N_(
1019 "disabling bitmap writing, as some objects are not being packed"
1020 );
1021
1022 static int add_object_entry(const unsigned char *sha1, enum object_type type,
1023                             const char *name, int exclude)
1024 {
1025         struct packed_git *found_pack;
1026         off_t found_offset;
1027         uint32_t index_pos;
1028
1029         if (have_duplicate_entry(sha1, exclude, &index_pos))
1030                 return 0;
1031
1032         if (!want_object_in_pack(sha1, exclude, &found_pack, &found_offset)) {
1033                 /* The pack is missing an object, so it will not have closure */
1034                 if (write_bitmap_index) {
1035                         warning(_(no_closure_warning));
1036                         write_bitmap_index = 0;
1037                 }
1038                 return 0;
1039         }
1040
1041         create_object_entry(sha1, type, pack_name_hash(name),
1042                             exclude, name && no_try_delta(name),
1043                             index_pos, found_pack, found_offset);
1044
1045         display_progress(progress_state, nr_result);
1046         return 1;
1047 }
1048
1049 static int add_object_entry_from_bitmap(const unsigned char *sha1,
1050                                         enum object_type type,
1051                                         int flags, uint32_t name_hash,
1052                                         struct packed_git *pack, off_t offset)
1053 {
1054         uint32_t index_pos;
1055
1056         if (have_duplicate_entry(sha1, 0, &index_pos))
1057                 return 0;
1058
1059         create_object_entry(sha1, type, name_hash, 0, 0, index_pos, pack, offset);
1060
1061         display_progress(progress_state, nr_result);
1062         return 1;
1063 }
1064
1065 struct pbase_tree_cache {
1066         unsigned char sha1[20];
1067         int ref;
1068         int temporary;
1069         void *tree_data;
1070         unsigned long tree_size;
1071 };
1072
1073 static struct pbase_tree_cache *(pbase_tree_cache[256]);
1074 static int pbase_tree_cache_ix(const unsigned char *sha1)
1075 {
1076         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
1077 }
1078 static int pbase_tree_cache_ix_incr(int ix)
1079 {
1080         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
1081 }
1082
1083 static struct pbase_tree {
1084         struct pbase_tree *next;
1085         /* This is a phony "cache" entry; we are not
1086          * going to evict it or find it through _get()
1087          * mechanism -- this is for the toplevel node that
1088          * would almost always change with any commit.
1089          */
1090         struct pbase_tree_cache pcache;
1091 } *pbase_tree;
1092
1093 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
1094 {
1095         struct pbase_tree_cache *ent, *nent;
1096         void *data;
1097         unsigned long size;
1098         enum object_type type;
1099         int neigh;
1100         int my_ix = pbase_tree_cache_ix(sha1);
1101         int available_ix = -1;
1102
1103         /* pbase-tree-cache acts as a limited hashtable.
1104          * your object will be found at your index or within a few
1105          * slots after that slot if it is cached.
1106          */
1107         for (neigh = 0; neigh < 8; neigh++) {
1108                 ent = pbase_tree_cache[my_ix];
1109                 if (ent && !hashcmp(ent->sha1, sha1)) {
1110                         ent->ref++;
1111                         return ent;
1112                 }
1113                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
1114                          ((0 <= available_ix) &&
1115                           (!ent && pbase_tree_cache[available_ix])))
1116                         available_ix = my_ix;
1117                 if (!ent)
1118                         break;
1119                 my_ix = pbase_tree_cache_ix_incr(my_ix);
1120         }
1121
1122         /* Did not find one.  Either we got a bogus request or
1123          * we need to read and perhaps cache.
1124          */
1125         data = read_sha1_file(sha1, &type, &size);
1126         if (!data)
1127                 return NULL;
1128         if (type != OBJ_TREE) {
1129                 free(data);
1130                 return NULL;
1131         }
1132
1133         /* We need to either cache or return a throwaway copy */
1134
1135         if (available_ix < 0)
1136                 ent = NULL;
1137         else {
1138                 ent = pbase_tree_cache[available_ix];
1139                 my_ix = available_ix;
1140         }
1141
1142         if (!ent) {
1143                 nent = xmalloc(sizeof(*nent));
1144                 nent->temporary = (available_ix < 0);
1145         }
1146         else {
1147                 /* evict and reuse */
1148                 free(ent->tree_data);
1149                 nent = ent;
1150         }
1151         hashcpy(nent->sha1, sha1);
1152         nent->tree_data = data;
1153         nent->tree_size = size;
1154         nent->ref = 1;
1155         if (!nent->temporary)
1156                 pbase_tree_cache[my_ix] = nent;
1157         return nent;
1158 }
1159
1160 static void pbase_tree_put(struct pbase_tree_cache *cache)
1161 {
1162         if (!cache->temporary) {
1163                 cache->ref--;
1164                 return;
1165         }
1166         free(cache->tree_data);
1167         free(cache);
1168 }
1169
1170 static int name_cmp_len(const char *name)
1171 {
1172         int i;
1173         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1174                 ;
1175         return i;
1176 }
1177
1178 static void add_pbase_object(struct tree_desc *tree,
1179                              const char *name,
1180                              int cmplen,
1181                              const char *fullname)
1182 {
1183         struct name_entry entry;
1184         int cmp;
1185
1186         while (tree_entry(tree,&entry)) {
1187                 if (S_ISGITLINK(entry.mode))
1188                         continue;
1189                 cmp = tree_entry_len(&entry) != cmplen ? 1 :
1190                       memcmp(name, entry.path, cmplen);
1191                 if (cmp > 0)
1192                         continue;
1193                 if (cmp < 0)
1194                         return;
1195                 if (name[cmplen] != '/') {
1196                         add_object_entry(entry.sha1,
1197                                          object_type(entry.mode),
1198                                          fullname, 1);
1199                         return;
1200                 }
1201                 if (S_ISDIR(entry.mode)) {
1202                         struct tree_desc sub;
1203                         struct pbase_tree_cache *tree;
1204                         const char *down = name+cmplen+1;
1205                         int downlen = name_cmp_len(down);
1206
1207                         tree = pbase_tree_get(entry.sha1);
1208                         if (!tree)
1209                                 return;
1210                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1211
1212                         add_pbase_object(&sub, down, downlen, fullname);
1213                         pbase_tree_put(tree);
1214                 }
1215         }
1216 }
1217
1218 static unsigned *done_pbase_paths;
1219 static int done_pbase_paths_num;
1220 static int done_pbase_paths_alloc;
1221 static int done_pbase_path_pos(unsigned hash)
1222 {
1223         int lo = 0;
1224         int hi = done_pbase_paths_num;
1225         while (lo < hi) {
1226                 int mi = (hi + lo) / 2;
1227                 if (done_pbase_paths[mi] == hash)
1228                         return mi;
1229                 if (done_pbase_paths[mi] < hash)
1230                         hi = mi;
1231                 else
1232                         lo = mi + 1;
1233         }
1234         return -lo-1;
1235 }
1236
1237 static int check_pbase_path(unsigned hash)
1238 {
1239         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1240         if (0 <= pos)
1241                 return 1;
1242         pos = -pos - 1;
1243         ALLOC_GROW(done_pbase_paths,
1244                    done_pbase_paths_num + 1,
1245                    done_pbase_paths_alloc);
1246         done_pbase_paths_num++;
1247         if (pos < done_pbase_paths_num)
1248                 memmove(done_pbase_paths + pos + 1,
1249                         done_pbase_paths + pos,
1250                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1251         done_pbase_paths[pos] = hash;
1252         return 0;
1253 }
1254
1255 static void add_preferred_base_object(const char *name)
1256 {
1257         struct pbase_tree *it;
1258         int cmplen;
1259         unsigned hash = pack_name_hash(name);
1260
1261         if (!num_preferred_base || check_pbase_path(hash))
1262                 return;
1263
1264         cmplen = name_cmp_len(name);
1265         for (it = pbase_tree; it; it = it->next) {
1266                 if (cmplen == 0) {
1267                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1268                 }
1269                 else {
1270                         struct tree_desc tree;
1271                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1272                         add_pbase_object(&tree, name, cmplen, name);
1273                 }
1274         }
1275 }
1276
1277 static void add_preferred_base(unsigned char *sha1)
1278 {
1279         struct pbase_tree *it;
1280         void *data;
1281         unsigned long size;
1282         unsigned char tree_sha1[20];
1283
1284         if (window <= num_preferred_base++)
1285                 return;
1286
1287         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1288         if (!data)
1289                 return;
1290
1291         for (it = pbase_tree; it; it = it->next) {
1292                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1293                         free(data);
1294                         return;
1295                 }
1296         }
1297
1298         it = xcalloc(1, sizeof(*it));
1299         it->next = pbase_tree;
1300         pbase_tree = it;
1301
1302         hashcpy(it->pcache.sha1, tree_sha1);
1303         it->pcache.tree_data = data;
1304         it->pcache.tree_size = size;
1305 }
1306
1307 static void cleanup_preferred_base(void)
1308 {
1309         struct pbase_tree *it;
1310         unsigned i;
1311
1312         it = pbase_tree;
1313         pbase_tree = NULL;
1314         while (it) {
1315                 struct pbase_tree *this = it;
1316                 it = this->next;
1317                 free(this->pcache.tree_data);
1318                 free(this);
1319         }
1320
1321         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1322                 if (!pbase_tree_cache[i])
1323                         continue;
1324                 free(pbase_tree_cache[i]->tree_data);
1325                 free(pbase_tree_cache[i]);
1326                 pbase_tree_cache[i] = NULL;
1327         }
1328
1329         free(done_pbase_paths);
1330         done_pbase_paths = NULL;
1331         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1332 }
1333
1334 static void check_object(struct object_entry *entry)
1335 {
1336         if (entry->in_pack) {
1337                 struct packed_git *p = entry->in_pack;
1338                 struct pack_window *w_curs = NULL;
1339                 const unsigned char *base_ref = NULL;
1340                 struct object_entry *base_entry;
1341                 unsigned long used, used_0;
1342                 unsigned long avail;
1343                 off_t ofs;
1344                 unsigned char *buf, c;
1345
1346                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1347
1348                 /*
1349                  * We want in_pack_type even if we do not reuse delta
1350                  * since non-delta representations could still be reused.
1351                  */
1352                 used = unpack_object_header_buffer(buf, avail,
1353                                                    &entry->in_pack_type,
1354                                                    &entry->size);
1355                 if (used == 0)
1356                         goto give_up;
1357
1358                 /*
1359                  * Determine if this is a delta and if so whether we can
1360                  * reuse it or not.  Otherwise let's find out as cheaply as
1361                  * possible what the actual type and size for this object is.
1362                  */
1363                 switch (entry->in_pack_type) {
1364                 default:
1365                         /* Not a delta hence we've already got all we need. */
1366                         entry->type = entry->in_pack_type;
1367                         entry->in_pack_header_size = used;
1368                         if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1369                                 goto give_up;
1370                         unuse_pack(&w_curs);
1371                         return;
1372                 case OBJ_REF_DELTA:
1373                         if (reuse_delta && !entry->preferred_base)
1374                                 base_ref = use_pack(p, &w_curs,
1375                                                 entry->in_pack_offset + used, NULL);
1376                         entry->in_pack_header_size = used + 20;
1377                         break;
1378                 case OBJ_OFS_DELTA:
1379                         buf = use_pack(p, &w_curs,
1380                                        entry->in_pack_offset + used, NULL);
1381                         used_0 = 0;
1382                         c = buf[used_0++];
1383                         ofs = c & 127;
1384                         while (c & 128) {
1385                                 ofs += 1;
1386                                 if (!ofs || MSB(ofs, 7)) {
1387                                         error("delta base offset overflow in pack for %s",
1388                                               sha1_to_hex(entry->idx.sha1));
1389                                         goto give_up;
1390                                 }
1391                                 c = buf[used_0++];
1392                                 ofs = (ofs << 7) + (c & 127);
1393                         }
1394                         ofs = entry->in_pack_offset - ofs;
1395                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1396                                 error("delta base offset out of bound for %s",
1397                                       sha1_to_hex(entry->idx.sha1));
1398                                 goto give_up;
1399                         }
1400                         if (reuse_delta && !entry->preferred_base) {
1401                                 struct revindex_entry *revidx;
1402                                 revidx = find_pack_revindex(p, ofs);
1403                                 if (!revidx)
1404                                         goto give_up;
1405                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1406                         }
1407                         entry->in_pack_header_size = used + used_0;
1408                         break;
1409                 }
1410
1411                 if (base_ref && (base_entry = packlist_find(&to_pack, base_ref, NULL))) {
1412                         /*
1413                          * If base_ref was set above that means we wish to
1414                          * reuse delta data, and we even found that base
1415                          * in the list of objects we want to pack. Goodie!
1416                          *
1417                          * Depth value does not matter - find_deltas() will
1418                          * never consider reused delta as the base object to
1419                          * deltify other objects against, in order to avoid
1420                          * circular deltas.
1421                          */
1422                         entry->type = entry->in_pack_type;
1423                         entry->delta = base_entry;
1424                         entry->delta_size = entry->size;
1425                         entry->delta_sibling = base_entry->delta_child;
1426                         base_entry->delta_child = entry;
1427                         unuse_pack(&w_curs);
1428                         return;
1429                 }
1430
1431                 if (entry->type) {
1432                         /*
1433                          * This must be a delta and we already know what the
1434                          * final object type is.  Let's extract the actual
1435                          * object size from the delta header.
1436                          */
1437                         entry->size = get_size_from_delta(p, &w_curs,
1438                                         entry->in_pack_offset + entry->in_pack_header_size);
1439                         if (entry->size == 0)
1440                                 goto give_up;
1441                         unuse_pack(&w_curs);
1442                         return;
1443                 }
1444
1445                 /*
1446                  * No choice but to fall back to the recursive delta walk
1447                  * with sha1_object_info() to find about the object type
1448                  * at this point...
1449                  */
1450                 give_up:
1451                 unuse_pack(&w_curs);
1452         }
1453
1454         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1455         /*
1456          * The error condition is checked in prepare_pack().  This is
1457          * to permit a missing preferred base object to be ignored
1458          * as a preferred base.  Doing so can result in a larger
1459          * pack file, but the transfer will still take place.
1460          */
1461 }
1462
1463 static int pack_offset_sort(const void *_a, const void *_b)
1464 {
1465         const struct object_entry *a = *(struct object_entry **)_a;
1466         const struct object_entry *b = *(struct object_entry **)_b;
1467
1468         /* avoid filesystem trashing with loose objects */
1469         if (!a->in_pack && !b->in_pack)
1470                 return hashcmp(a->idx.sha1, b->idx.sha1);
1471
1472         if (a->in_pack < b->in_pack)
1473                 return -1;
1474         if (a->in_pack > b->in_pack)
1475                 return 1;
1476         return a->in_pack_offset < b->in_pack_offset ? -1 :
1477                         (a->in_pack_offset > b->in_pack_offset);
1478 }
1479
1480 static void get_object_details(void)
1481 {
1482         uint32_t i;
1483         struct object_entry **sorted_by_offset;
1484
1485         sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
1486         for (i = 0; i < to_pack.nr_objects; i++)
1487                 sorted_by_offset[i] = to_pack.objects + i;
1488         qsort(sorted_by_offset, to_pack.nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1489
1490         for (i = 0; i < to_pack.nr_objects; i++) {
1491                 struct object_entry *entry = sorted_by_offset[i];
1492                 check_object(entry);
1493                 if (big_file_threshold < entry->size)
1494                         entry->no_try_delta = 1;
1495         }
1496
1497         free(sorted_by_offset);
1498 }
1499
1500 /*
1501  * We search for deltas in a list sorted by type, by filename hash, and then
1502  * by size, so that we see progressively smaller and smaller files.
1503  * That's because we prefer deltas to be from the bigger file
1504  * to the smaller -- deletes are potentially cheaper, but perhaps
1505  * more importantly, the bigger file is likely the more recent
1506  * one.  The deepest deltas are therefore the oldest objects which are
1507  * less susceptible to be accessed often.
1508  */
1509 static int type_size_sort(const void *_a, const void *_b)
1510 {
1511         const struct object_entry *a = *(struct object_entry **)_a;
1512         const struct object_entry *b = *(struct object_entry **)_b;
1513
1514         if (a->type > b->type)
1515                 return -1;
1516         if (a->type < b->type)
1517                 return 1;
1518         if (a->hash > b->hash)
1519                 return -1;
1520         if (a->hash < b->hash)
1521                 return 1;
1522         if (a->preferred_base > b->preferred_base)
1523                 return -1;
1524         if (a->preferred_base < b->preferred_base)
1525                 return 1;
1526         if (a->size > b->size)
1527                 return -1;
1528         if (a->size < b->size)
1529                 return 1;
1530         return a < b ? -1 : (a > b);  /* newest first */
1531 }
1532
1533 struct unpacked {
1534         struct object_entry *entry;
1535         void *data;
1536         struct delta_index *index;
1537         unsigned depth;
1538 };
1539
1540 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1541                            unsigned long delta_size)
1542 {
1543         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1544                 return 0;
1545
1546         if (delta_size < cache_max_small_delta_size)
1547                 return 1;
1548
1549         /* cache delta, if objects are large enough compared to delta size */
1550         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1551                 return 1;
1552
1553         return 0;
1554 }
1555
1556 #ifndef NO_PTHREADS
1557
1558 static pthread_mutex_t read_mutex;
1559 #define read_lock()             pthread_mutex_lock(&read_mutex)
1560 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1561
1562 static pthread_mutex_t cache_mutex;
1563 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1564 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1565
1566 static pthread_mutex_t progress_mutex;
1567 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1568 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1569
1570 #else
1571
1572 #define read_lock()             (void)0
1573 #define read_unlock()           (void)0
1574 #define cache_lock()            (void)0
1575 #define cache_unlock()          (void)0
1576 #define progress_lock()         (void)0
1577 #define progress_unlock()       (void)0
1578
1579 #endif
1580
1581 static int try_delta(struct unpacked *trg, struct unpacked *src,
1582                      unsigned max_depth, unsigned long *mem_usage)
1583 {
1584         struct object_entry *trg_entry = trg->entry;
1585         struct object_entry *src_entry = src->entry;
1586         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1587         unsigned ref_depth;
1588         enum object_type type;
1589         void *delta_buf;
1590
1591         /* Don't bother doing diffs between different types */
1592         if (trg_entry->type != src_entry->type)
1593                 return -1;
1594
1595         /*
1596          * We do not bother to try a delta that we discarded on an
1597          * earlier try, but only when reusing delta data.  Note that
1598          * src_entry that is marked as the preferred_base should always
1599          * be considered, as even if we produce a suboptimal delta against
1600          * it, we will still save the transfer cost, as we already know
1601          * the other side has it and we won't send src_entry at all.
1602          */
1603         if (reuse_delta && trg_entry->in_pack &&
1604             trg_entry->in_pack == src_entry->in_pack &&
1605             !src_entry->preferred_base &&
1606             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1607             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1608                 return 0;
1609
1610         /* Let's not bust the allowed depth. */
1611         if (src->depth >= max_depth)
1612                 return 0;
1613
1614         /* Now some size filtering heuristics. */
1615         trg_size = trg_entry->size;
1616         if (!trg_entry->delta) {
1617                 max_size = trg_size/2 - 20;
1618                 ref_depth = 1;
1619         } else {
1620                 max_size = trg_entry->delta_size;
1621                 ref_depth = trg->depth;
1622         }
1623         max_size = (uint64_t)max_size * (max_depth - src->depth) /
1624                                                 (max_depth - ref_depth + 1);
1625         if (max_size == 0)
1626                 return 0;
1627         src_size = src_entry->size;
1628         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1629         if (sizediff >= max_size)
1630                 return 0;
1631         if (trg_size < src_size / 32)
1632                 return 0;
1633
1634         /* Load data if not already done */
1635         if (!trg->data) {
1636                 read_lock();
1637                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1638                 read_unlock();
1639                 if (!trg->data)
1640                         die("object %s cannot be read",
1641                             sha1_to_hex(trg_entry->idx.sha1));
1642                 if (sz != trg_size)
1643                         die("object %s inconsistent object length (%lu vs %lu)",
1644                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1645                 *mem_usage += sz;
1646         }
1647         if (!src->data) {
1648                 read_lock();
1649                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1650                 read_unlock();
1651                 if (!src->data) {
1652                         if (src_entry->preferred_base) {
1653                                 static int warned = 0;
1654                                 if (!warned++)
1655                                         warning("object %s cannot be read",
1656                                                 sha1_to_hex(src_entry->idx.sha1));
1657                                 /*
1658                                  * Those objects are not included in the
1659                                  * resulting pack.  Be resilient and ignore
1660                                  * them if they can't be read, in case the
1661                                  * pack could be created nevertheless.
1662                                  */
1663                                 return 0;
1664                         }
1665                         die("object %s cannot be read",
1666                             sha1_to_hex(src_entry->idx.sha1));
1667                 }
1668                 if (sz != src_size)
1669                         die("object %s inconsistent object length (%lu vs %lu)",
1670                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1671                 *mem_usage += sz;
1672         }
1673         if (!src->index) {
1674                 src->index = create_delta_index(src->data, src_size);
1675                 if (!src->index) {
1676                         static int warned = 0;
1677                         if (!warned++)
1678                                 warning("suboptimal pack - out of memory");
1679                         return 0;
1680                 }
1681                 *mem_usage += sizeof_delta_index(src->index);
1682         }
1683
1684         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1685         if (!delta_buf)
1686                 return 0;
1687
1688         if (trg_entry->delta) {
1689                 /* Prefer only shallower same-sized deltas. */
1690                 if (delta_size == trg_entry->delta_size &&
1691                     src->depth + 1 >= trg->depth) {
1692                         free(delta_buf);
1693                         return 0;
1694                 }
1695         }
1696
1697         /*
1698          * Handle memory allocation outside of the cache
1699          * accounting lock.  Compiler will optimize the strangeness
1700          * away when NO_PTHREADS is defined.
1701          */
1702         free(trg_entry->delta_data);
1703         cache_lock();
1704         if (trg_entry->delta_data) {
1705                 delta_cache_size -= trg_entry->delta_size;
1706                 trg_entry->delta_data = NULL;
1707         }
1708         if (delta_cacheable(src_size, trg_size, delta_size)) {
1709                 delta_cache_size += delta_size;
1710                 cache_unlock();
1711                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1712         } else {
1713                 cache_unlock();
1714                 free(delta_buf);
1715         }
1716
1717         trg_entry->delta = src_entry;
1718         trg_entry->delta_size = delta_size;
1719         trg->depth = src->depth + 1;
1720
1721         return 1;
1722 }
1723
1724 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1725 {
1726         struct object_entry *child = me->delta_child;
1727         unsigned int m = n;
1728         while (child) {
1729                 unsigned int c = check_delta_limit(child, n + 1);
1730                 if (m < c)
1731                         m = c;
1732                 child = child->delta_sibling;
1733         }
1734         return m;
1735 }
1736
1737 static unsigned long free_unpacked(struct unpacked *n)
1738 {
1739         unsigned long freed_mem = sizeof_delta_index(n->index);
1740         free_delta_index(n->index);
1741         n->index = NULL;
1742         if (n->data) {
1743                 freed_mem += n->entry->size;
1744                 free(n->data);
1745                 n->data = NULL;
1746         }
1747         n->entry = NULL;
1748         n->depth = 0;
1749         return freed_mem;
1750 }
1751
1752 static void find_deltas(struct object_entry **list, unsigned *list_size,
1753                         int window, int depth, unsigned *processed)
1754 {
1755         uint32_t i, idx = 0, count = 0;
1756         struct unpacked *array;
1757         unsigned long mem_usage = 0;
1758
1759         array = xcalloc(window, sizeof(struct unpacked));
1760
1761         for (;;) {
1762                 struct object_entry *entry;
1763                 struct unpacked *n = array + idx;
1764                 int j, max_depth, best_base = -1;
1765
1766                 progress_lock();
1767                 if (!*list_size) {
1768                         progress_unlock();
1769                         break;
1770                 }
1771                 entry = *list++;
1772                 (*list_size)--;
1773                 if (!entry->preferred_base) {
1774                         (*processed)++;
1775                         display_progress(progress_state, *processed);
1776                 }
1777                 progress_unlock();
1778
1779                 mem_usage -= free_unpacked(n);
1780                 n->entry = entry;
1781
1782                 while (window_memory_limit &&
1783                        mem_usage > window_memory_limit &&
1784                        count > 1) {
1785                         uint32_t tail = (idx + window - count) % window;
1786                         mem_usage -= free_unpacked(array + tail);
1787                         count--;
1788                 }
1789
1790                 /* We do not compute delta to *create* objects we are not
1791                  * going to pack.
1792                  */
1793                 if (entry->preferred_base)
1794                         goto next;
1795
1796                 /*
1797                  * If the current object is at pack edge, take the depth the
1798                  * objects that depend on the current object into account
1799                  * otherwise they would become too deep.
1800                  */
1801                 max_depth = depth;
1802                 if (entry->delta_child) {
1803                         max_depth -= check_delta_limit(entry, 0);
1804                         if (max_depth <= 0)
1805                                 goto next;
1806                 }
1807
1808                 j = window;
1809                 while (--j > 0) {
1810                         int ret;
1811                         uint32_t other_idx = idx + j;
1812                         struct unpacked *m;
1813                         if (other_idx >= window)
1814                                 other_idx -= window;
1815                         m = array + other_idx;
1816                         if (!m->entry)
1817                                 break;
1818                         ret = try_delta(n, m, max_depth, &mem_usage);
1819                         if (ret < 0)
1820                                 break;
1821                         else if (ret > 0)
1822                                 best_base = other_idx;
1823                 }
1824
1825                 /*
1826                  * If we decided to cache the delta data, then it is best
1827                  * to compress it right away.  First because we have to do
1828                  * it anyway, and doing it here while we're threaded will
1829                  * save a lot of time in the non threaded write phase,
1830                  * as well as allow for caching more deltas within
1831                  * the same cache size limit.
1832                  * ...
1833                  * But only if not writing to stdout, since in that case
1834                  * the network is most likely throttling writes anyway,
1835                  * and therefore it is best to go to the write phase ASAP
1836                  * instead, as we can afford spending more time compressing
1837                  * between writes at that moment.
1838                  */
1839                 if (entry->delta_data && !pack_to_stdout) {
1840                         entry->z_delta_size = do_compress(&entry->delta_data,
1841                                                           entry->delta_size);
1842                         cache_lock();
1843                         delta_cache_size -= entry->delta_size;
1844                         delta_cache_size += entry->z_delta_size;
1845                         cache_unlock();
1846                 }
1847
1848                 /* if we made n a delta, and if n is already at max
1849                  * depth, leaving it in the window is pointless.  we
1850                  * should evict it first.
1851                  */
1852                 if (entry->delta && max_depth <= n->depth)
1853                         continue;
1854
1855                 /*
1856                  * Move the best delta base up in the window, after the
1857                  * currently deltified object, to keep it longer.  It will
1858                  * be the first base object to be attempted next.
1859                  */
1860                 if (entry->delta) {
1861                         struct unpacked swap = array[best_base];
1862                         int dist = (window + idx - best_base) % window;
1863                         int dst = best_base;
1864                         while (dist--) {
1865                                 int src = (dst + 1) % window;
1866                                 array[dst] = array[src];
1867                                 dst = src;
1868                         }
1869                         array[dst] = swap;
1870                 }
1871
1872                 next:
1873                 idx++;
1874                 if (count + 1 < window)
1875                         count++;
1876                 if (idx >= window)
1877                         idx = 0;
1878         }
1879
1880         for (i = 0; i < window; ++i) {
1881                 free_delta_index(array[i].index);
1882                 free(array[i].data);
1883         }
1884         free(array);
1885 }
1886
1887 #ifndef NO_PTHREADS
1888
1889 static void try_to_free_from_threads(size_t size)
1890 {
1891         read_lock();
1892         release_pack_memory(size);
1893         read_unlock();
1894 }
1895
1896 static try_to_free_t old_try_to_free_routine;
1897
1898 /*
1899  * The main thread waits on the condition that (at least) one of the workers
1900  * has stopped working (which is indicated in the .working member of
1901  * struct thread_params).
1902  * When a work thread has completed its work, it sets .working to 0 and
1903  * signals the main thread and waits on the condition that .data_ready
1904  * becomes 1.
1905  */
1906
1907 struct thread_params {
1908         pthread_t thread;
1909         struct object_entry **list;
1910         unsigned list_size;
1911         unsigned remaining;
1912         int window;
1913         int depth;
1914         int working;
1915         int data_ready;
1916         pthread_mutex_t mutex;
1917         pthread_cond_t cond;
1918         unsigned *processed;
1919 };
1920
1921 static pthread_cond_t progress_cond;
1922
1923 /*
1924  * Mutex and conditional variable can't be statically-initialized on Windows.
1925  */
1926 static void init_threaded_search(void)
1927 {
1928         init_recursive_mutex(&read_mutex);
1929         pthread_mutex_init(&cache_mutex, NULL);
1930         pthread_mutex_init(&progress_mutex, NULL);
1931         pthread_cond_init(&progress_cond, NULL);
1932         old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
1933 }
1934
1935 static void cleanup_threaded_search(void)
1936 {
1937         set_try_to_free_routine(old_try_to_free_routine);
1938         pthread_cond_destroy(&progress_cond);
1939         pthread_mutex_destroy(&read_mutex);
1940         pthread_mutex_destroy(&cache_mutex);
1941         pthread_mutex_destroy(&progress_mutex);
1942 }
1943
1944 static void *threaded_find_deltas(void *arg)
1945 {
1946         struct thread_params *me = arg;
1947
1948         while (me->remaining) {
1949                 find_deltas(me->list, &me->remaining,
1950                             me->window, me->depth, me->processed);
1951
1952                 progress_lock();
1953                 me->working = 0;
1954                 pthread_cond_signal(&progress_cond);
1955                 progress_unlock();
1956
1957                 /*
1958                  * We must not set ->data_ready before we wait on the
1959                  * condition because the main thread may have set it to 1
1960                  * before we get here. In order to be sure that new
1961                  * work is available if we see 1 in ->data_ready, it
1962                  * was initialized to 0 before this thread was spawned
1963                  * and we reset it to 0 right away.
1964                  */
1965                 pthread_mutex_lock(&me->mutex);
1966                 while (!me->data_ready)
1967                         pthread_cond_wait(&me->cond, &me->mutex);
1968                 me->data_ready = 0;
1969                 pthread_mutex_unlock(&me->mutex);
1970         }
1971         /* leave ->working 1 so that this doesn't get more work assigned */
1972         return NULL;
1973 }
1974
1975 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1976                            int window, int depth, unsigned *processed)
1977 {
1978         struct thread_params *p;
1979         int i, ret, active_threads = 0;
1980
1981         init_threaded_search();
1982
1983         if (delta_search_threads <= 1) {
1984                 find_deltas(list, &list_size, window, depth, processed);
1985                 cleanup_threaded_search();
1986                 return;
1987         }
1988         if (progress > pack_to_stdout)
1989                 fprintf(stderr, "Delta compression using up to %d threads.\n",
1990                                 delta_search_threads);
1991         p = xcalloc(delta_search_threads, sizeof(*p));
1992
1993         /* Partition the work amongst work threads. */
1994         for (i = 0; i < delta_search_threads; i++) {
1995                 unsigned sub_size = list_size / (delta_search_threads - i);
1996
1997                 /* don't use too small segments or no deltas will be found */
1998                 if (sub_size < 2*window && i+1 < delta_search_threads)
1999                         sub_size = 0;
2000
2001                 p[i].window = window;
2002                 p[i].depth = depth;
2003                 p[i].processed = processed;
2004                 p[i].working = 1;
2005                 p[i].data_ready = 0;
2006
2007                 /* try to split chunks on "path" boundaries */
2008                 while (sub_size && sub_size < list_size &&
2009                        list[sub_size]->hash &&
2010                        list[sub_size]->hash == list[sub_size-1]->hash)
2011                         sub_size++;
2012
2013                 p[i].list = list;
2014                 p[i].list_size = sub_size;
2015                 p[i].remaining = sub_size;
2016
2017                 list += sub_size;
2018                 list_size -= sub_size;
2019         }
2020
2021         /* Start work threads. */
2022         for (i = 0; i < delta_search_threads; i++) {
2023                 if (!p[i].list_size)
2024                         continue;
2025                 pthread_mutex_init(&p[i].mutex, NULL);
2026                 pthread_cond_init(&p[i].cond, NULL);
2027                 ret = pthread_create(&p[i].thread, NULL,
2028                                      threaded_find_deltas, &p[i]);
2029                 if (ret)
2030                         die("unable to create thread: %s", strerror(ret));
2031                 active_threads++;
2032         }
2033
2034         /*
2035          * Now let's wait for work completion.  Each time a thread is done
2036          * with its work, we steal half of the remaining work from the
2037          * thread with the largest number of unprocessed objects and give
2038          * it to that newly idle thread.  This ensure good load balancing
2039          * until the remaining object list segments are simply too short
2040          * to be worth splitting anymore.
2041          */
2042         while (active_threads) {
2043                 struct thread_params *target = NULL;
2044                 struct thread_params *victim = NULL;
2045                 unsigned sub_size = 0;
2046
2047                 progress_lock();
2048                 for (;;) {
2049                         for (i = 0; !target && i < delta_search_threads; i++)
2050                                 if (!p[i].working)
2051                                         target = &p[i];
2052                         if (target)
2053                                 break;
2054                         pthread_cond_wait(&progress_cond, &progress_mutex);
2055                 }
2056
2057                 for (i = 0; i < delta_search_threads; i++)
2058                         if (p[i].remaining > 2*window &&
2059                             (!victim || victim->remaining < p[i].remaining))
2060                                 victim = &p[i];
2061                 if (victim) {
2062                         sub_size = victim->remaining / 2;
2063                         list = victim->list + victim->list_size - sub_size;
2064                         while (sub_size && list[0]->hash &&
2065                                list[0]->hash == list[-1]->hash) {
2066                                 list++;
2067                                 sub_size--;
2068                         }
2069                         if (!sub_size) {
2070                                 /*
2071                                  * It is possible for some "paths" to have
2072                                  * so many objects that no hash boundary
2073                                  * might be found.  Let's just steal the
2074                                  * exact half in that case.
2075                                  */
2076                                 sub_size = victim->remaining / 2;
2077                                 list -= sub_size;
2078                         }
2079                         target->list = list;
2080                         victim->list_size -= sub_size;
2081                         victim->remaining -= sub_size;
2082                 }
2083                 target->list_size = sub_size;
2084                 target->remaining = sub_size;
2085                 target->working = 1;
2086                 progress_unlock();
2087
2088                 pthread_mutex_lock(&target->mutex);
2089                 target->data_ready = 1;
2090                 pthread_cond_signal(&target->cond);
2091                 pthread_mutex_unlock(&target->mutex);
2092
2093                 if (!sub_size) {
2094                         pthread_join(target->thread, NULL);
2095                         pthread_cond_destroy(&target->cond);
2096                         pthread_mutex_destroy(&target->mutex);
2097                         active_threads--;
2098                 }
2099         }
2100         cleanup_threaded_search();
2101         free(p);
2102 }
2103
2104 #else
2105 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
2106 #endif
2107
2108 static int add_ref_tag(const char *path, const struct object_id *oid, int flag, void *cb_data)
2109 {
2110         struct object_id peeled;
2111
2112         if (starts_with(path, "refs/tags/") && /* is a tag? */
2113             !peel_ref(path, peeled.hash)    && /* peelable? */
2114             packlist_find(&to_pack, peeled.hash, NULL))      /* object packed? */
2115                 add_object_entry(oid->hash, OBJ_TAG, NULL, 0);
2116         return 0;
2117 }
2118
2119 static void prepare_pack(int window, int depth)
2120 {
2121         struct object_entry **delta_list;
2122         uint32_t i, nr_deltas;
2123         unsigned n;
2124
2125         get_object_details();
2126
2127         /*
2128          * If we're locally repacking then we need to be doubly careful
2129          * from now on in order to make sure no stealth corruption gets
2130          * propagated to the new pack.  Clients receiving streamed packs
2131          * should validate everything they get anyway so no need to incur
2132          * the additional cost here in that case.
2133          */
2134         if (!pack_to_stdout)
2135                 do_check_packed_object_crc = 1;
2136
2137         if (!to_pack.nr_objects || !window || !depth)
2138                 return;
2139
2140         ALLOC_ARRAY(delta_list, to_pack.nr_objects);
2141         nr_deltas = n = 0;
2142
2143         for (i = 0; i < to_pack.nr_objects; i++) {
2144                 struct object_entry *entry = to_pack.objects + i;
2145
2146                 if (entry->delta)
2147                         /* This happens if we decided to reuse existing
2148                          * delta from a pack.  "reuse_delta &&" is implied.
2149                          */
2150                         continue;
2151
2152                 if (entry->size < 50)
2153                         continue;
2154
2155                 if (entry->no_try_delta)
2156                         continue;
2157
2158                 if (!entry->preferred_base) {
2159                         nr_deltas++;
2160                         if (entry->type < 0)
2161                                 die("unable to get type of object %s",
2162                                     sha1_to_hex(entry->idx.sha1));
2163                 } else {
2164                         if (entry->type < 0) {
2165                                 /*
2166                                  * This object is not found, but we
2167                                  * don't have to include it anyway.
2168                                  */
2169                                 continue;
2170                         }
2171                 }
2172
2173                 delta_list[n++] = entry;
2174         }
2175
2176         if (nr_deltas && n > 1) {
2177                 unsigned nr_done = 0;
2178                 if (progress)
2179                         progress_state = start_progress(_("Compressing objects"),
2180                                                         nr_deltas);
2181                 qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
2182                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2183                 stop_progress(&progress_state);
2184                 if (nr_done != nr_deltas)
2185                         die("inconsistency with delta count");
2186         }
2187         free(delta_list);
2188 }
2189
2190 static int git_pack_config(const char *k, const char *v, void *cb)
2191 {
2192         if (!strcmp(k, "pack.window")) {
2193                 window = git_config_int(k, v);
2194                 return 0;
2195         }
2196         if (!strcmp(k, "pack.windowmemory")) {
2197                 window_memory_limit = git_config_ulong(k, v);
2198                 return 0;
2199         }
2200         if (!strcmp(k, "pack.depth")) {
2201                 depth = git_config_int(k, v);
2202                 return 0;
2203         }
2204         if (!strcmp(k, "pack.compression")) {
2205                 int level = git_config_int(k, v);
2206                 if (level == -1)
2207                         level = Z_DEFAULT_COMPRESSION;
2208                 else if (level < 0 || level > Z_BEST_COMPRESSION)
2209                         die("bad pack compression level %d", level);
2210                 pack_compression_level = level;
2211                 pack_compression_seen = 1;
2212                 return 0;
2213         }
2214         if (!strcmp(k, "pack.deltacachesize")) {
2215                 max_delta_cache_size = git_config_int(k, v);
2216                 return 0;
2217         }
2218         if (!strcmp(k, "pack.deltacachelimit")) {
2219                 cache_max_small_delta_size = git_config_int(k, v);
2220                 return 0;
2221         }
2222         if (!strcmp(k, "pack.writebitmaphashcache")) {
2223                 if (git_config_bool(k, v))
2224                         write_bitmap_options |= BITMAP_OPT_HASH_CACHE;
2225                 else
2226                         write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
2227         }
2228         if (!strcmp(k, "pack.usebitmaps")) {
2229                 use_bitmap_index = git_config_bool(k, v);
2230                 return 0;
2231         }
2232         if (!strcmp(k, "pack.threads")) {
2233                 delta_search_threads = git_config_int(k, v);
2234                 if (delta_search_threads < 0)
2235                         die("invalid number of threads specified (%d)",
2236                             delta_search_threads);
2237 #ifdef NO_PTHREADS
2238                 if (delta_search_threads != 1)
2239                         warning("no threads support, ignoring %s", k);
2240 #endif
2241                 return 0;
2242         }
2243         if (!strcmp(k, "pack.indexversion")) {
2244                 pack_idx_opts.version = git_config_int(k, v);
2245                 if (pack_idx_opts.version > 2)
2246                         die("bad pack.indexversion=%"PRIu32,
2247                             pack_idx_opts.version);
2248                 return 0;
2249         }
2250         return git_default_config(k, v, cb);
2251 }
2252
2253 static void read_object_list_from_stdin(void)
2254 {
2255         char line[40 + 1 + PATH_MAX + 2];
2256         unsigned char sha1[20];
2257
2258         for (;;) {
2259                 if (!fgets(line, sizeof(line), stdin)) {
2260                         if (feof(stdin))
2261                                 break;
2262                         if (!ferror(stdin))
2263                                 die("fgets returned NULL, not EOF, not error!");
2264                         if (errno != EINTR)
2265                                 die_errno("fgets");
2266                         clearerr(stdin);
2267                         continue;
2268                 }
2269                 if (line[0] == '-') {
2270                         if (get_sha1_hex(line+1, sha1))
2271                                 die("expected edge sha1, got garbage:\n %s",
2272                                     line);
2273                         add_preferred_base(sha1);
2274                         continue;
2275                 }
2276                 if (get_sha1_hex(line, sha1))
2277                         die("expected sha1, got garbage:\n %s", line);
2278
2279                 add_preferred_base_object(line+41);
2280                 add_object_entry(sha1, 0, line+41, 0);
2281         }
2282 }
2283
2284 #define OBJECT_ADDED (1u<<20)
2285
2286 static void show_commit(struct commit *commit, void *data)
2287 {
2288         add_object_entry(commit->object.oid.hash, OBJ_COMMIT, NULL, 0);
2289         commit->object.flags |= OBJECT_ADDED;
2290
2291         if (write_bitmap_index)
2292                 index_commit_for_bitmap(commit);
2293 }
2294
2295 static void show_object(struct object *obj, const char *name, void *data)
2296 {
2297         add_preferred_base_object(name);
2298         add_object_entry(obj->oid.hash, obj->type, name, 0);
2299         obj->flags |= OBJECT_ADDED;
2300 }
2301
2302 static void show_edge(struct commit *commit)
2303 {
2304         add_preferred_base(commit->object.oid.hash);
2305 }
2306
2307 struct in_pack_object {
2308         off_t offset;
2309         struct object *object;
2310 };
2311
2312 struct in_pack {
2313         int alloc;
2314         int nr;
2315         struct in_pack_object *array;
2316 };
2317
2318 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2319 {
2320         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->oid.hash, p);
2321         in_pack->array[in_pack->nr].object = object;
2322         in_pack->nr++;
2323 }
2324
2325 /*
2326  * Compare the objects in the offset order, in order to emulate the
2327  * "git rev-list --objects" output that produced the pack originally.
2328  */
2329 static int ofscmp(const void *a_, const void *b_)
2330 {
2331         struct in_pack_object *a = (struct in_pack_object *)a_;
2332         struct in_pack_object *b = (struct in_pack_object *)b_;
2333
2334         if (a->offset < b->offset)
2335                 return -1;
2336         else if (a->offset > b->offset)
2337                 return 1;
2338         else
2339                 return oidcmp(&a->object->oid, &b->object->oid);
2340 }
2341
2342 static void add_objects_in_unpacked_packs(struct rev_info *revs)
2343 {
2344         struct packed_git *p;
2345         struct in_pack in_pack;
2346         uint32_t i;
2347
2348         memset(&in_pack, 0, sizeof(in_pack));
2349
2350         for (p = packed_git; p; p = p->next) {
2351                 const unsigned char *sha1;
2352                 struct object *o;
2353
2354                 if (!p->pack_local || p->pack_keep)
2355                         continue;
2356                 if (open_pack_index(p))
2357                         die("cannot open pack index");
2358
2359                 ALLOC_GROW(in_pack.array,
2360                            in_pack.nr + p->num_objects,
2361                            in_pack.alloc);
2362
2363                 for (i = 0; i < p->num_objects; i++) {
2364                         sha1 = nth_packed_object_sha1(p, i);
2365                         o = lookup_unknown_object(sha1);
2366                         if (!(o->flags & OBJECT_ADDED))
2367                                 mark_in_pack_object(o, p, &in_pack);
2368                         o->flags |= OBJECT_ADDED;
2369                 }
2370         }
2371
2372         if (in_pack.nr) {
2373                 qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
2374                       ofscmp);
2375                 for (i = 0; i < in_pack.nr; i++) {
2376                         struct object *o = in_pack.array[i].object;
2377                         add_object_entry(o->oid.hash, o->type, "", 0);
2378                 }
2379         }
2380         free(in_pack.array);
2381 }
2382
2383 static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
2384 {
2385         static struct packed_git *last_found = (void *)1;
2386         struct packed_git *p;
2387
2388         p = (last_found != (void *)1) ? last_found : packed_git;
2389
2390         while (p) {
2391                 if ((!p->pack_local || p->pack_keep) &&
2392                         find_pack_entry_one(sha1, p)) {
2393                         last_found = p;
2394                         return 1;
2395                 }
2396                 if (p == last_found)
2397                         p = packed_git;
2398                 else
2399                         p = p->next;
2400                 if (p == last_found)
2401                         p = p->next;
2402         }
2403         return 0;
2404 }
2405
2406 /*
2407  * Store a list of sha1s that are should not be discarded
2408  * because they are either written too recently, or are
2409  * reachable from another object that was.
2410  *
2411  * This is filled by get_object_list.
2412  */
2413 static struct sha1_array recent_objects;
2414
2415 static int loosened_object_can_be_discarded(const unsigned char *sha1,
2416                                             unsigned long mtime)
2417 {
2418         if (!unpack_unreachable_expiration)
2419                 return 0;
2420         if (mtime > unpack_unreachable_expiration)
2421                 return 0;
2422         if (sha1_array_lookup(&recent_objects, sha1) >= 0)
2423                 return 0;
2424         return 1;
2425 }
2426
2427 static void loosen_unused_packed_objects(struct rev_info *revs)
2428 {
2429         struct packed_git *p;
2430         uint32_t i;
2431         const unsigned char *sha1;
2432
2433         for (p = packed_git; p; p = p->next) {
2434                 if (!p->pack_local || p->pack_keep)
2435                         continue;
2436
2437                 if (open_pack_index(p))
2438                         die("cannot open pack index");
2439
2440                 for (i = 0; i < p->num_objects; i++) {
2441                         sha1 = nth_packed_object_sha1(p, i);
2442                         if (!packlist_find(&to_pack, sha1, NULL) &&
2443                             !has_sha1_pack_kept_or_nonlocal(sha1) &&
2444                             !loosened_object_can_be_discarded(sha1, p->mtime))
2445                                 if (force_object_loose(sha1, p->mtime))
2446                                         die("unable to force loose object");
2447                 }
2448         }
2449 }
2450
2451 /*
2452  * This tracks any options which a reader of the pack might
2453  * not understand, and which would therefore prevent blind reuse
2454  * of what we have on disk.
2455  */
2456 static int pack_options_allow_reuse(void)
2457 {
2458         return allow_ofs_delta;
2459 }
2460
2461 static int get_object_list_from_bitmap(struct rev_info *revs)
2462 {
2463         if (prepare_bitmap_walk(revs) < 0)
2464                 return -1;
2465
2466         if (pack_options_allow_reuse() &&
2467             !reuse_partial_packfile_from_bitmap(
2468                         &reuse_packfile,
2469                         &reuse_packfile_objects,
2470                         &reuse_packfile_offset)) {
2471                 assert(reuse_packfile_objects);
2472                 nr_result += reuse_packfile_objects;
2473                 display_progress(progress_state, nr_result);
2474         }
2475
2476         traverse_bitmap_commit_list(&add_object_entry_from_bitmap);
2477         return 0;
2478 }
2479
2480 static void record_recent_object(struct object *obj,
2481                                  const char *name,
2482                                  void *data)
2483 {
2484         sha1_array_append(&recent_objects, obj->oid.hash);
2485 }
2486
2487 static void record_recent_commit(struct commit *commit, void *data)
2488 {
2489         sha1_array_append(&recent_objects, commit->object.oid.hash);
2490 }
2491
2492 static void get_object_list(int ac, const char **av)
2493 {
2494         struct rev_info revs;
2495         char line[1000];
2496         int flags = 0;
2497
2498         init_revisions(&revs, NULL);
2499         save_commit_buffer = 0;
2500         setup_revisions(ac, av, &revs, NULL);
2501
2502         /* make sure shallows are read */
2503         is_repository_shallow();
2504
2505         while (fgets(line, sizeof(line), stdin) != NULL) {
2506                 int len = strlen(line);
2507                 if (len && line[len - 1] == '\n')
2508                         line[--len] = 0;
2509                 if (!len)
2510                         break;
2511                 if (*line == '-') {
2512                         if (!strcmp(line, "--not")) {
2513                                 flags ^= UNINTERESTING;
2514                                 write_bitmap_index = 0;
2515                                 continue;
2516                         }
2517                         if (starts_with(line, "--shallow ")) {
2518                                 unsigned char sha1[20];
2519                                 if (get_sha1_hex(line + 10, sha1))
2520                                         die("not an SHA-1 '%s'", line + 10);
2521                                 register_shallow(sha1);
2522                                 use_bitmap_index = 0;
2523                                 continue;
2524                         }
2525                         die("not a rev '%s'", line);
2526                 }
2527                 if (handle_revision_arg(line, &revs, flags, REVARG_CANNOT_BE_FILENAME))
2528                         die("bad revision '%s'", line);
2529         }
2530
2531         if (use_bitmap_index && !get_object_list_from_bitmap(&revs))
2532                 return;
2533
2534         if (prepare_revision_walk(&revs))
2535                 die("revision walk setup failed");
2536         mark_edges_uninteresting(&revs, show_edge);
2537         traverse_commit_list(&revs, show_commit, show_object, NULL);
2538
2539         if (unpack_unreachable_expiration) {
2540                 revs.ignore_missing_links = 1;
2541                 if (add_unseen_recent_objects_to_traversal(&revs,
2542                                 unpack_unreachable_expiration))
2543                         die("unable to add recent objects");
2544                 if (prepare_revision_walk(&revs))
2545                         die("revision walk setup failed");
2546                 traverse_commit_list(&revs, record_recent_commit,
2547                                      record_recent_object, NULL);
2548         }
2549
2550         if (keep_unreachable)
2551                 add_objects_in_unpacked_packs(&revs);
2552         if (unpack_unreachable)
2553                 loosen_unused_packed_objects(&revs);
2554
2555         sha1_array_clear(&recent_objects);
2556 }
2557
2558 static int option_parse_index_version(const struct option *opt,
2559                                       const char *arg, int unset)
2560 {
2561         char *c;
2562         const char *val = arg;
2563         pack_idx_opts.version = strtoul(val, &c, 10);
2564         if (pack_idx_opts.version > 2)
2565                 die(_("unsupported index version %s"), val);
2566         if (*c == ',' && c[1])
2567                 pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2568         if (*c || pack_idx_opts.off32_limit & 0x80000000)
2569                 die(_("bad index version '%s'"), val);
2570         return 0;
2571 }
2572
2573 static int option_parse_unpack_unreachable(const struct option *opt,
2574                                            const char *arg, int unset)
2575 {
2576         if (unset) {
2577                 unpack_unreachable = 0;
2578                 unpack_unreachable_expiration = 0;
2579         }
2580         else {
2581                 unpack_unreachable = 1;
2582                 if (arg)
2583                         unpack_unreachable_expiration = approxidate(arg);
2584         }
2585         return 0;
2586 }
2587
2588 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2589 {
2590         int use_internal_rev_list = 0;
2591         int thin = 0;
2592         int shallow = 0;
2593         int all_progress_implied = 0;
2594         struct argv_array rp = ARGV_ARRAY_INIT;
2595         int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
2596         int rev_list_index = 0;
2597         struct option pack_objects_options[] = {
2598                 OPT_SET_INT('q', "quiet", &progress,
2599                             N_("do not show progress meter"), 0),
2600                 OPT_SET_INT(0, "progress", &progress,
2601                             N_("show progress meter"), 1),
2602                 OPT_SET_INT(0, "all-progress", &progress,
2603                             N_("show progress meter during object writing phase"), 2),
2604                 OPT_BOOL(0, "all-progress-implied",
2605                          &all_progress_implied,
2606                          N_("similar to --all-progress when progress meter is shown")),
2607                 { OPTION_CALLBACK, 0, "index-version", NULL, N_("version[,offset]"),
2608                   N_("write the pack index file in the specified idx format version"),
2609                   0, option_parse_index_version },
2610                 OPT_MAGNITUDE(0, "max-pack-size", &pack_size_limit,
2611                               N_("maximum size of each output pack file")),
2612                 OPT_BOOL(0, "local", &local,
2613                          N_("ignore borrowed objects from alternate object store")),
2614                 OPT_BOOL(0, "incremental", &incremental,
2615                          N_("ignore packed objects")),
2616                 OPT_INTEGER(0, "window", &window,
2617                             N_("limit pack window by objects")),
2618                 OPT_MAGNITUDE(0, "window-memory", &window_memory_limit,
2619                               N_("limit pack window by memory in addition to object limit")),
2620                 OPT_INTEGER(0, "depth", &depth,
2621                             N_("maximum length of delta chain allowed in the resulting pack")),
2622                 OPT_BOOL(0, "reuse-delta", &reuse_delta,
2623                          N_("reuse existing deltas")),
2624                 OPT_BOOL(0, "reuse-object", &reuse_object,
2625                          N_("reuse existing objects")),
2626                 OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
2627                          N_("use OFS_DELTA objects")),
2628                 OPT_INTEGER(0, "threads", &delta_search_threads,
2629                             N_("use threads when searching for best delta matches")),
2630                 OPT_BOOL(0, "non-empty", &non_empty,
2631                          N_("do not create an empty pack output")),
2632                 OPT_BOOL(0, "revs", &use_internal_rev_list,
2633                          N_("read revision arguments from standard input")),
2634                 { OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
2635                   N_("limit the objects to those that are not yet packed"),
2636                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2637                 { OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
2638                   N_("include objects reachable from any reference"),
2639                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2640                 { OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
2641                   N_("include objects referred by reflog entries"),
2642                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2643                 { OPTION_SET_INT, 0, "indexed-objects", &rev_list_index, NULL,
2644                   N_("include objects referred to by the index"),
2645                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2646                 OPT_BOOL(0, "stdout", &pack_to_stdout,
2647                          N_("output pack to stdout")),
2648                 OPT_BOOL(0, "include-tag", &include_tag,
2649                          N_("include tag objects that refer to objects to be packed")),
2650                 OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
2651                          N_("keep unreachable objects")),
2652                 { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, N_("time"),
2653                   N_("unpack unreachable objects newer than <time>"),
2654                   PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
2655                 OPT_BOOL(0, "thin", &thin,
2656                          N_("create thin packs")),
2657                 OPT_BOOL(0, "shallow", &shallow,
2658                          N_("create packs suitable for shallow fetches")),
2659                 OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
2660                          N_("ignore packs that have companion .keep file")),
2661                 OPT_INTEGER(0, "compression", &pack_compression_level,
2662                             N_("pack compression level")),
2663                 OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
2664                             N_("do not hide commits by grafts"), 0),
2665                 OPT_BOOL(0, "use-bitmap-index", &use_bitmap_index,
2666                          N_("use a bitmap index if available to speed up counting objects")),
2667                 OPT_BOOL(0, "write-bitmap-index", &write_bitmap_index,
2668                          N_("write a bitmap index together with the pack index")),
2669                 OPT_END(),
2670         };
2671
2672         check_replace_refs = 0;
2673
2674         reset_pack_idx_option(&pack_idx_opts);
2675         git_config(git_pack_config, NULL);
2676         if (!pack_compression_seen && core_compression_seen)
2677                 pack_compression_level = core_compression_level;
2678
2679         progress = isatty(2);
2680         argc = parse_options(argc, argv, prefix, pack_objects_options,
2681                              pack_usage, 0);
2682
2683         if (argc) {
2684                 base_name = argv[0];
2685                 argc--;
2686         }
2687         if (pack_to_stdout != !base_name || argc)
2688                 usage_with_options(pack_usage, pack_objects_options);
2689
2690         argv_array_push(&rp, "pack-objects");
2691         if (thin) {
2692                 use_internal_rev_list = 1;
2693                 argv_array_push(&rp, shallow
2694                                 ? "--objects-edge-aggressive"
2695                                 : "--objects-edge");
2696         } else
2697                 argv_array_push(&rp, "--objects");
2698
2699         if (rev_list_all) {
2700                 use_internal_rev_list = 1;
2701                 argv_array_push(&rp, "--all");
2702         }
2703         if (rev_list_reflog) {
2704                 use_internal_rev_list = 1;
2705                 argv_array_push(&rp, "--reflog");
2706         }
2707         if (rev_list_index) {
2708                 use_internal_rev_list = 1;
2709                 argv_array_push(&rp, "--indexed-objects");
2710         }
2711         if (rev_list_unpacked) {
2712                 use_internal_rev_list = 1;
2713                 argv_array_push(&rp, "--unpacked");
2714         }
2715
2716         if (!reuse_object)
2717                 reuse_delta = 0;
2718         if (pack_compression_level == -1)
2719                 pack_compression_level = Z_DEFAULT_COMPRESSION;
2720         else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
2721                 die("bad pack compression level %d", pack_compression_level);
2722
2723         if (!delta_search_threads)      /* --threads=0 means autodetect */
2724                 delta_search_threads = online_cpus();
2725
2726 #ifdef NO_PTHREADS
2727         if (delta_search_threads != 1)
2728                 warning("no threads support, ignoring --threads");
2729 #endif
2730         if (!pack_to_stdout && !pack_size_limit)
2731                 pack_size_limit = pack_size_limit_cfg;
2732         if (pack_to_stdout && pack_size_limit)
2733                 die("--max-pack-size cannot be used to build a pack for transfer.");
2734         if (pack_size_limit && pack_size_limit < 1024*1024) {
2735                 warning("minimum pack size limit is 1 MiB");
2736                 pack_size_limit = 1024*1024;
2737         }
2738
2739         if (!pack_to_stdout && thin)
2740                 die("--thin cannot be used to build an indexable pack.");
2741
2742         if (keep_unreachable && unpack_unreachable)
2743                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
2744         if (!rev_list_all || !rev_list_reflog || !rev_list_index)
2745                 unpack_unreachable_expiration = 0;
2746
2747         if (!use_internal_rev_list || !pack_to_stdout || is_repository_shallow())
2748                 use_bitmap_index = 0;
2749
2750         if (pack_to_stdout || !rev_list_all)
2751                 write_bitmap_index = 0;
2752
2753         if (progress && all_progress_implied)
2754                 progress = 2;
2755
2756         prepare_packed_git();
2757
2758         if (progress)
2759                 progress_state = start_progress(_("Counting objects"), 0);
2760         if (!use_internal_rev_list)
2761                 read_object_list_from_stdin();
2762         else {
2763                 get_object_list(rp.argc, rp.argv);
2764                 argv_array_clear(&rp);
2765         }
2766         cleanup_preferred_base();
2767         if (include_tag && nr_result)
2768                 for_each_ref(add_ref_tag, NULL);
2769         stop_progress(&progress_state);
2770
2771         if (non_empty && !nr_result)
2772                 return 0;
2773         if (nr_result)
2774                 prepare_pack(window, depth);
2775         write_pack_file();
2776         if (progress)
2777                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
2778                         " reused %"PRIu32" (delta %"PRIu32")\n",
2779                         written, written_delta, reused, reused_delta);
2780         return 0;
2781 }