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