builtin/pack-objects.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "repository.h"
   4 #include "config.h"
   5 #include "attr.h"
   6 #include "object.h"
   7 #include "blob.h"
   8 #include "commit.h"
   9 #include "tag.h"
  10 #include "tree.h"
  11 #include "delta.h"
  12 #include "pack.h"
  13 #include "pack-revindex.h"
  14 #include "csum-file.h"
  15 #include "tree-walk.h"
  16 #include "diff.h"
  17 #include "revision.h"
  18 #include "list-objects.h"
  19 #include "list-objects-filter.h"
  20 #include "list-objects-filter-options.h"
  21 #include "pack-objects.h"
  22 #include "progress.h"
  23 #include "refs.h"
  24 #include "streaming.h"
  25 #include "thread-utils.h"
  26 #include "pack-bitmap.h"
  27 #include "delta-islands.h"
  28 #include "reachable.h"
  29 #include "sha1-array.h"
  30 #include "argv-array.h"
  31 #include "list.h"
  32 #include "packfile.h"
  33 #include "object-store.h"
  34 #include "dir.h"
  35 #include "midx.h"
  36
  37 #define IN_PACK(obj) oe_in_pack(&to_pack, obj)
  38 #define SIZE(obj) oe_size(&to_pack, obj)
  39 #define SET_SIZE(obj,size) oe_set_size(&to_pack, obj, size)
  40 #define DELTA_SIZE(obj) oe_delta_size(&to_pack, obj)
  41 #define DELTA(obj) oe_delta(&to_pack, obj)
  42 #define DELTA_CHILD(obj) oe_delta_child(&to_pack, obj)
  43 #define DELTA_SIBLING(obj) oe_delta_sibling(&to_pack, obj)
  44 #define SET_DELTA(obj, val) oe_set_delta(&to_pack, obj, val)
  45 #define SET_DELTA_EXT(obj, oid) oe_set_delta_ext(&to_pack, obj, oid)
  46 #define SET_DELTA_SIZE(obj, val) oe_set_delta_size(&to_pack, obj, val)
  47 #define SET_DELTA_CHILD(obj, val) oe_set_delta_child(&to_pack, obj, val)
  48 #define SET_DELTA_SIBLING(obj, val) oe_set_delta_sibling(&to_pack, obj, val)
  49
  50 static const char *pack_usage[] = {
  51         N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
  52         N_("git pack-objects [<options>...] <base-name> [< <ref-list> | < <object-list>]"),
  53         NULL
  54 };
  55
  56 /*
  57  * Objects we are going to pack are collected in the `to_pack` structure.
  58  * It contains an array (dynamically expanded) of the object data, and a map
  59  * that can resolve SHA1s to their position in the array.
  60  */
  61 static struct packing_data to_pack;
  62
  63 static struct pack_idx_entry **written_list;
  64 static uint32_t nr_result, nr_written, nr_seen;
  65 static struct bitmap_index *bitmap_git;
  66 static uint32_t write_layer;
  67
  68 static int non_empty;
  69 static int reuse_delta = 1, reuse_object = 1;
  70 static int keep_unreachable, unpack_unreachable, include_tag;
  71 static timestamp_t unpack_unreachable_expiration;
  72 static int pack_loose_unreachable;
  73 static int local;
  74 static int have_non_local_packs;
  75 static int incremental;
  76 static int ignore_packed_keep_on_disk;
  77 static int ignore_packed_keep_in_core;
  78 static int allow_ofs_delta;
  79 static struct pack_idx_option pack_idx_opts;
  80 static const char *base_name;
  81 static int progress = 1;
  82 static int window = 10;
  83 static unsigned long pack_size_limit;
  84 static int depth = 50;
  85 static int delta_search_threads;
  86 static int pack_to_stdout;
  87 static int sparse;
  88 static int thin;
  89 static int num_preferred_base;
  90 static struct progress *progress_state;
  91
  92 static struct packed_git *reuse_packfile;
  93 static uint32_t reuse_packfile_objects;
  94 static off_t reuse_packfile_offset;
  95
  96 static int use_bitmap_index_default = 1;
  97 static int use_bitmap_index = -1;
  98 static int write_bitmap_index;
  99 static uint16_t write_bitmap_options;
 100
 101 static int exclude_promisor_objects;
 102
 103 static int use_delta_islands;
 104
 105 static unsigned long delta_cache_size = 0;
 106 static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
 107 static unsigned long cache_max_small_delta_size = 1000;
 108
 109 static unsigned long window_memory_limit = 0;
 110
 111 static struct list_objects_filter_options filter_options;
 112
 113 enum missing_action {
 114         MA_ERROR = 0,      /* fail if any missing objects are encountered */
 115         MA_ALLOW_ANY,      /* silently allow ALL missing objects */
 116         MA_ALLOW_PROMISOR, /* silently allow all missing PROMISOR objects */
 117 };
 118 static enum missing_action arg_missing_action;
 119 static show_object_fn fn_show_object;
 120
 121 /*
 122  * stats
 123  */
 124 static uint32_t written, written_delta;
 125 static uint32_t reused, reused_delta;
 126
 127 /*
 128  * Indexed commits
 129  */
 130 static struct commit **indexed_commits;
 131 static unsigned int indexed_commits_nr;
 132 static unsigned int indexed_commits_alloc;
 133
 134 static void index_commit_for_bitmap(struct commit *commit)
 135 {
 136         if (indexed_commits_nr >= indexed_commits_alloc) {
 137                 indexed_commits_alloc = (indexed_commits_alloc + 32) * 2;
 138                 REALLOC_ARRAY(indexed_commits, indexed_commits_alloc);
 139         }
 140
 141         indexed_commits[indexed_commits_nr++] = commit;
 142 }
 143
 144 static void *get_delta(struct object_entry *entry)
 145 {
 146         unsigned long size, base_size, delta_size;
 147         void *buf, *base_buf, *delta_buf;
 148         enum object_type type;
 149
 150         buf = read_object_file(&entry->idx.oid, &type, &size);
 151         if (!buf)
 152                 die(_("unable to read %s"), oid_to_hex(&entry->idx.oid));
 153         base_buf = read_object_file(&DELTA(entry)->idx.oid, &type,
 154                                     &base_size);
 155         if (!base_buf)
 156                 die("unable to read %s",
 157                     oid_to_hex(&DELTA(entry)->idx.oid));
 158         delta_buf = diff_delta(base_buf, base_size,
 159                                buf, size, &delta_size, 0);
 160         /*
 161          * We succesfully computed this delta once but dropped it for
 162          * memory reasons. Something is very wrong if this time we
 163          * recompute and create a different delta.
 164          */
 165         if (!delta_buf || delta_size != DELTA_SIZE(entry))
 166                 BUG("delta size changed");
 167         free(buf);
 168         free(base_buf);
 169         return delta_buf;
 170 }
 171
 172 static unsigned long do_compress(void **pptr, unsigned long size)
 173 {
 174         git_zstream stream;
 175         void *in, *out;
 176         unsigned long maxsize;
 177
 178         git_deflate_init(&stream, pack_compression_level);
 179         maxsize = git_deflate_bound(&stream, size);
 180
 181         in = *pptr;
 182         out = xmalloc(maxsize);
 183         *pptr = out;
 184
 185         stream.next_in = in;
 186         stream.avail_in = size;
 187         stream.next_out = out;
 188         stream.avail_out = maxsize;
 189         while (git_deflate(&stream, Z_FINISH) == Z_OK)
 190                 ; /* nothing */
 191         git_deflate_end(&stream);
 192
 193         free(in);
 194         return stream.total_out;
 195 }
 196
 197 static unsigned long write_large_blob_data(struct git_istream *st, struct hashfile *f,
 198                                            const struct object_id *oid)
 199 {
 200         git_zstream stream;
 201         unsigned char ibuf[1024 * 16];
 202         unsigned char obuf[1024 * 16];
 203         unsigned long olen = 0;
 204
 205         git_deflate_init(&stream, pack_compression_level);
 206
 207         for (;;) {
 208                 ssize_t readlen;
 209                 int zret = Z_OK;
 210                 readlen = read_istream(st, ibuf, sizeof(ibuf));
 211                 if (readlen == -1)
 212                         die(_("unable to read %s"), oid_to_hex(oid));
 213
 214                 stream.next_in = ibuf;
 215                 stream.avail_in = readlen;
 216                 while ((stream.avail_in || readlen == 0) &&
 217                        (zret == Z_OK || zret == Z_BUF_ERROR)) {
 218                         stream.next_out = obuf;
 219                         stream.avail_out = sizeof(obuf);
 220                         zret = git_deflate(&stream, readlen ? 0 : Z_FINISH);
 221                         hashwrite(f, obuf, stream.next_out - obuf);
 222                         olen += stream.next_out - obuf;
 223                 }
 224                 if (stream.avail_in)
 225                         die(_("deflate error (%d)"), zret);
 226                 if (readlen == 0) {
 227                         if (zret != Z_STREAM_END)
 228                                 die(_("deflate error (%d)"), zret);
 229                         break;
 230                 }
 231         }
 232         git_deflate_end(&stream);
 233         return olen;
 234 }
 235
 236 /*
 237  * we are going to reuse the existing object data as is.  make
 238  * sure it is not corrupt.
 239  */
 240 static int check_pack_inflate(struct packed_git *p,
 241                 struct pack_window **w_curs,
 242                 off_t offset,
 243                 off_t len,
 244                 unsigned long expect)
 245 {
 246         git_zstream stream;
 247         unsigned char fakebuf[4096], *in;
 248         int st;
 249
 250         memset(&stream, 0, sizeof(stream));
 251         git_inflate_init(&stream);
 252         do {
 253                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 254                 stream.next_in = in;
 255                 stream.next_out = fakebuf;
 256                 stream.avail_out = sizeof(fakebuf);
 257                 st = git_inflate(&stream, Z_FINISH);
 258                 offset += stream.next_in - in;
 259         } while (st == Z_OK || st == Z_BUF_ERROR);
 260         git_inflate_end(&stream);
 261         return (st == Z_STREAM_END &&
 262                 stream.total_out == expect &&
 263                 stream.total_in == len) ? 0 : -1;
 264 }
 265
 266 static void copy_pack_data(struct hashfile *f,
 267                 struct packed_git *p,
 268                 struct pack_window **w_curs,
 269                 off_t offset,
 270                 off_t len)
 271 {
 272         unsigned char *in;
 273         unsigned long avail;
 274
 275         while (len) {
 276                 in = use_pack(p, w_curs, offset, &avail);
 277                 if (avail > len)
 278                         avail = (unsigned long)len;
 279                 hashwrite(f, in, avail);
 280                 offset += avail;
 281                 len -= avail;
 282         }
 283 }
 284
 285 /* Return 0 if we will bust the pack-size limit */
 286 static unsigned long write_no_reuse_object(struct hashfile *f, struct object_entry *entry,
 287                                            unsigned long limit, int usable_delta)
 288 {
 289         unsigned long size, datalen;
 290         unsigned char header[MAX_PACK_OBJECT_HEADER],
 291                       dheader[MAX_PACK_OBJECT_HEADER];
 292         unsigned hdrlen;
 293         enum object_type type;
 294         void *buf;
 295         struct git_istream *st = NULL;
 296         const unsigned hashsz = the_hash_algo->rawsz;
 297
 298         if (!usable_delta) {
 299                 if (oe_type(entry) == OBJ_BLOB &&
 300                     oe_size_greater_than(&to_pack, entry, big_file_threshold) &&
 301                     (st = open_istream(&entry->idx.oid, &type, &size, NULL)) != NULL)
 302                         buf = NULL;
 303                 else {
 304                         buf = read_object_file(&entry->idx.oid, &type, &size);
 305                         if (!buf)
 306                                 die(_("unable to read %s"),
 307                                     oid_to_hex(&entry->idx.oid));
 308                 }
 309                 /*
 310                  * make sure no cached delta data remains from a
 311                  * previous attempt before a pack split occurred.
 312                  */
 313                 FREE_AND_NULL(entry->delta_data);
 314                 entry->z_delta_size = 0;
 315         } else if (entry->delta_data) {
 316                 size = DELTA_SIZE(entry);
 317                 buf = entry->delta_data;
 318                 entry->delta_data = NULL;
 319                 type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 320                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 321         } else {
 322                 buf = get_delta(entry);
 323                 size = DELTA_SIZE(entry);
 324                 type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 325                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 326         }
 327
 328         if (st) /* large blob case, just assume we don't compress well */
 329                 datalen = size;
 330         else if (entry->z_delta_size)
 331                 datalen = entry->z_delta_size;
 332         else
 333                 datalen = do_compress(&buf, size);
 334
 335         /*
 336          * The object header is a byte of 'type' followed by zero or
 337          * more bytes of length.
 338          */
 339         hdrlen = encode_in_pack_object_header(header, sizeof(header),
 340                                               type, size);
 341
 342         if (type == OBJ_OFS_DELTA) {
 343                 /*
 344                  * Deltas with relative base contain an additional
 345                  * encoding of the relative offset for the delta
 346                  * base from this object's position in the pack.
 347                  */
 348                 off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 349                 unsigned pos = sizeof(dheader) - 1;
 350                 dheader[pos] = ofs & 127;
 351                 while (ofs >>= 7)
 352                         dheader[--pos] = 128 | (--ofs & 127);
 353                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 354                         if (st)
 355                                 close_istream(st);
 356                         free(buf);
 357                         return 0;
 358                 }
 359                 hashwrite(f, header, hdrlen);
 360                 hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 361                 hdrlen += sizeof(dheader) - pos;
 362         } else if (type == OBJ_REF_DELTA) {
 363                 /*
 364                  * Deltas with a base reference contain
 365                  * additional bytes for the base object ID.
 366                  */
 367                 if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 368                         if (st)
 369                                 close_istream(st);
 370                         free(buf);
 371                         return 0;
 372                 }
 373                 hashwrite(f, header, hdrlen);
 374                 hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
 375                 hdrlen += hashsz;
 376         } else {
 377                 if (limit && hdrlen + datalen + hashsz >= limit) {
 378                         if (st)
 379                                 close_istream(st);
 380                         free(buf);
 381                         return 0;
 382                 }
 383                 hashwrite(f, header, hdrlen);
 384         }
 385         if (st) {
 386                 datalen = write_large_blob_data(st, f, &entry->idx.oid);
 387                 close_istream(st);
 388         } else {
 389                 hashwrite(f, buf, datalen);
 390                 free(buf);
 391         }
 392
 393         return hdrlen + datalen;
 394 }
 395
 396 /* Return 0 if we will bust the pack-size limit */
 397 static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 398                                 unsigned long limit, int usable_delta)
 399 {
 400         struct packed_git *p = IN_PACK(entry);
 401         struct pack_window *w_curs = NULL;
 402         struct revindex_entry *revidx;
 403         off_t offset;
 404         enum object_type type = oe_type(entry);
 405         off_t datalen;
 406         unsigned char header[MAX_PACK_OBJECT_HEADER],
 407                       dheader[MAX_PACK_OBJECT_HEADER];
 408         unsigned hdrlen;
 409         const unsigned hashsz = the_hash_algo->rawsz;
 410         unsigned long entry_size = SIZE(entry);
 411
 412         if (DELTA(entry))
 413                 type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 414                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 415         hdrlen = encode_in_pack_object_header(header, sizeof(header),
 416                                               type, entry_size);
 417
 418         offset = entry->in_pack_offset;
 419         revidx = find_pack_revindex(p, offset);
 420         datalen = revidx[1].offset - offset;
 421         if (!pack_to_stdout && p->index_version > 1 &&
 422             check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 423                 error(_("bad packed object CRC for %s"),
 424                       oid_to_hex(&entry->idx.oid));
 425                 unuse_pack(&w_curs);
 426                 return write_no_reuse_object(f, entry, limit, usable_delta);
 427         }
 428
 429         offset += entry->in_pack_header_size;
 430         datalen -= entry->in_pack_header_size;
 431
 432         if (!pack_to_stdout && p->index_version == 1 &&
 433             check_pack_inflate(p, &w_curs, offset, datalen, entry_size)) {
 434                 error(_("corrupt packed object for %s"),
 435                       oid_to_hex(&entry->idx.oid));
 436                 unuse_pack(&w_curs);
 437                 return write_no_reuse_object(f, entry, limit, usable_delta);
 438         }
 439
 440         if (type == OBJ_OFS_DELTA) {
 441                 off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 442                 unsigned pos = sizeof(dheader) - 1;
 443                 dheader[pos] = ofs & 127;
 444                 while (ofs >>= 7)
 445                         dheader[--pos] = 128 | (--ofs & 127);
 446                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 447                         unuse_pack(&w_curs);
 448                         return 0;
 449                 }
 450                 hashwrite(f, header, hdrlen);
 451                 hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 452                 hdrlen += sizeof(dheader) - pos;
 453                 reused_delta++;
 454         } else if (type == OBJ_REF_DELTA) {
 455                 if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 456                         unuse_pack(&w_curs);
 457                         return 0;
 458                 }
 459                 hashwrite(f, header, hdrlen);
 460                 hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
 461                 hdrlen += hashsz;
 462                 reused_delta++;
 463         } else {
 464                 if (limit && hdrlen + datalen + hashsz >= limit) {
 465                         unuse_pack(&w_curs);
 466                         return 0;
 467                 }
 468                 hashwrite(f, header, hdrlen);
 469         }
 470         copy_pack_data(f, p, &w_curs, offset, datalen);
 471         unuse_pack(&w_curs);
 472         reused++;
 473         return hdrlen + datalen;
 474 }
 475
 476 /* Return 0 if we will bust the pack-size limit */
 477 static off_t write_object(struct hashfile *f,
 478                           struct object_entry *entry,
 479                           off_t write_offset)
 480 {
 481         unsigned long limit;
 482         off_t len;
 483         int usable_delta, to_reuse;
 484
 485         if (!pack_to_stdout)
 486                 crc32_begin(f);
 487
 488         /* apply size limit if limited packsize and not first object */
 489         if (!pack_size_limit || !nr_written)
 490                 limit = 0;
 491         else if (pack_size_limit <= write_offset)
 492                 /*
 493                  * the earlier object did not fit the limit; avoid
 494                  * mistaking this with unlimited (i.e. limit = 0).
 495                  */
 496                 limit = 1;
 497         else
 498                 limit = pack_size_limit - write_offset;
 499
 500         if (!DELTA(entry))
 501                 usable_delta = 0;       /* no delta */
 502         else if (!pack_size_limit)
 503                usable_delta = 1;        /* unlimited packfile */
 504         else if (DELTA(entry)->idx.offset == (off_t)-1)
 505                 usable_delta = 0;       /* base was written to another pack */
 506         else if (DELTA(entry)->idx.offset)
 507                 usable_delta = 1;       /* base already exists in this pack */
 508         else
 509                 usable_delta = 0;       /* base could end up in another pack */
 510
 511         if (!reuse_object)
 512                 to_reuse = 0;   /* explicit */
 513         else if (!IN_PACK(entry))
 514                 to_reuse = 0;   /* can't reuse what we don't have */
 515         else if (oe_type(entry) == OBJ_REF_DELTA ||
 516                  oe_type(entry) == OBJ_OFS_DELTA)
 517                                 /* check_object() decided it for us ... */
 518                 to_reuse = usable_delta;
 519                                 /* ... but pack split may override that */
 520         else if (oe_type(entry) != entry->in_pack_type)
 521                 to_reuse = 0;   /* pack has delta which is unusable */
 522         else if (DELTA(entry))
 523                 to_reuse = 0;   /* we want to pack afresh */
 524         else
 525                 to_reuse = 1;   /* we have it in-pack undeltified,
 526                                  * and we do not need to deltify it.
 527                                  */
 528
 529         if (!to_reuse)
 530                 len = write_no_reuse_object(f, entry, limit, usable_delta);
 531         else
 532                 len = write_reuse_object(f, entry, limit, usable_delta);
 533         if (!len)
 534                 return 0;
 535
 536         if (usable_delta)
 537                 written_delta++;
 538         written++;
 539         if (!pack_to_stdout)
 540                 entry->idx.crc32 = crc32_end(f);
 541         return len;
 542 }
 543
 544 enum write_one_status {
 545         WRITE_ONE_SKIP = -1, /* already written */
 546         WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 547         WRITE_ONE_WRITTEN = 1, /* normal */
 548         WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 549 };
 550
 551 static enum write_one_status write_one(struct hashfile *f,
 552                                        struct object_entry *e,
 553                                        off_t *offset)
 554 {
 555         off_t size;
 556         int recursing;
 557
 558         /*
 559          * we set offset to 1 (which is an impossible value) to mark
 560          * the fact that this object is involved in "write its base
 561          * first before writing a deltified object" recursion.
 562          */
 563         recursing = (e->idx.offset == 1);
 564         if (recursing) {
 565                 warning(_("recursive delta detected for object %s"),
 566                         oid_to_hex(&e->idx.oid));
 567                 return WRITE_ONE_RECURSIVE;
 568         } else if (e->idx.offset || e->preferred_base) {
 569                 /* offset is non zero if object is written already. */
 570                 return WRITE_ONE_SKIP;
 571         }
 572
 573         /* if we are deltified, write out base object first. */
 574         if (DELTA(e)) {
 575                 e->idx.offset = 1; /* now recurse */
 576                 switch (write_one(f, DELTA(e), offset)) {
 577                 case WRITE_ONE_RECURSIVE:
 578                         /* we cannot depend on this one */
 579                         SET_DELTA(e, NULL);
 580                         break;
 581                 default:
 582                         break;
 583                 case WRITE_ONE_BREAK:
 584                         e->idx.offset = recursing;
 585                         return WRITE_ONE_BREAK;
 586                 }
 587         }
 588
 589         e->idx.offset = *offset;
 590         size = write_object(f, e, *offset);
 591         if (!size) {
 592                 e->idx.offset = recursing;
 593                 return WRITE_ONE_BREAK;
 594         }
 595         written_list[nr_written++] = &e->idx;
 596
 597         /* make sure off_t is sufficiently large not to wrap */
 598         if (signed_add_overflows(*offset, size))
 599                 die(_("pack too large for current definition of off_t"));
 600         *offset += size;
 601         return WRITE_ONE_WRITTEN;
 602 }
 603
 604 static int mark_tagged(const char *path, const struct object_id *oid, int flag,
 605                        void *cb_data)
 606 {
 607         struct object_id peeled;
 608         struct object_entry *entry = packlist_find(&to_pack, oid->hash, NULL);
 609
 610         if (entry)
 611                 entry->tagged = 1;
 612         if (!peel_ref(path, &peeled)) {
 613                 entry = packlist_find(&to_pack, peeled.hash, NULL);
 614                 if (entry)
 615                         entry->tagged = 1;
 616         }
 617         return 0;
 618 }
 619
 620 static inline void add_to_write_order(struct object_entry **wo,
 621                                unsigned int *endp,
 622                                struct object_entry *e)
 623 {
 624         if (e->filled || oe_layer(&to_pack, e) != write_layer)
 625                 return;
 626         wo[(*endp)++] = e;
 627         e->filled = 1;
 628 }
 629
 630 static void add_descendants_to_write_order(struct object_entry **wo,
 631                                            unsigned int *endp,
 632                                            struct object_entry *e)
 633 {
 634         int add_to_order = 1;
 635         while (e) {
 636                 if (add_to_order) {
 637                         struct object_entry *s;
 638                         /* add this node... */
 639                         add_to_write_order(wo, endp, e);
 640                         /* all its siblings... */
 641                         for (s = DELTA_SIBLING(e); s; s = DELTA_SIBLING(s)) {
 642                                 add_to_write_order(wo, endp, s);
 643                         }
 644                 }
 645                 /* drop down a level to add left subtree nodes if possible */
 646                 if (DELTA_CHILD(e)) {
 647                         add_to_order = 1;
 648                         e = DELTA_CHILD(e);
 649                 } else {
 650                         add_to_order = 0;
 651                         /* our sibling might have some children, it is next */
 652                         if (DELTA_SIBLING(e)) {
 653                                 e = DELTA_SIBLING(e);
 654                                 continue;
 655                         }
 656                         /* go back to our parent node */
 657                         e = DELTA(e);
 658                         while (e && !DELTA_SIBLING(e)) {
 659                                 /* we're on the right side of a subtree, keep
 660                                  * going up until we can go right again */
 661                                 e = DELTA(e);
 662                         }
 663                         if (!e) {
 664                                 /* done- we hit our original root node */
 665                                 return;
 666                         }
 667                         /* pass it off to sibling at this level */
 668                         e = DELTA_SIBLING(e);
 669                 }
 670         };
 671 }
 672
 673 static void add_family_to_write_order(struct object_entry **wo,
 674                                       unsigned int *endp,
 675                                       struct object_entry *e)
 676 {
 677         struct object_entry *root;
 678
 679         for (root = e; DELTA(root); root = DELTA(root))
 680                 ; /* nothing */
 681         add_descendants_to_write_order(wo, endp, root);
 682 }
 683
 684 static void compute_layer_order(struct object_entry **wo, unsigned int *wo_end)
 685 {
 686         unsigned int i, last_untagged;
 687         struct object_entry *objects = to_pack.objects;
 688
 689         for (i = 0; i < to_pack.nr_objects; i++) {
 690                 if (objects[i].tagged)
 691                         break;
 692                 add_to_write_order(wo, wo_end, &objects[i]);
 693         }
 694         last_untagged = i;
 695
 696         /*
 697          * Then fill all the tagged tips.
 698          */
 699         for (; i < to_pack.nr_objects; i++) {
 700                 if (objects[i].tagged)
 701                         add_to_write_order(wo, wo_end, &objects[i]);
 702         }
 703
 704         /*
 705          * And then all remaining commits and tags.
 706          */
 707         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 708                 if (oe_type(&objects[i]) != OBJ_COMMIT &&
 709                     oe_type(&objects[i]) != OBJ_TAG)
 710                         continue;
 711                 add_to_write_order(wo, wo_end, &objects[i]);
 712         }
 713
 714         /*
 715          * And then all the trees.
 716          */
 717         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 718                 if (oe_type(&objects[i]) != OBJ_TREE)
 719                         continue;
 720                 add_to_write_order(wo, wo_end, &objects[i]);
 721         }
 722
 723         /*
 724          * Finally all the rest in really tight order
 725          */
 726         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 727                 if (!objects[i].filled && oe_layer(&to_pack, &objects[i]) == write_layer)
 728                         add_family_to_write_order(wo, wo_end, &objects[i]);
 729         }
 730 }
 731
 732 static struct object_entry **compute_write_order(void)
 733 {
 734         uint32_t max_layers = 1;
 735         unsigned int i, wo_end;
 736
 737         struct object_entry **wo;
 738         struct object_entry *objects = to_pack.objects;
 739
 740         for (i = 0; i < to_pack.nr_objects; i++) {
 741                 objects[i].tagged = 0;
 742                 objects[i].filled = 0;
 743                 SET_DELTA_CHILD(&objects[i], NULL);
 744                 SET_DELTA_SIBLING(&objects[i], NULL);
 745         }
 746
 747         /*
 748          * Fully connect delta_child/delta_sibling network.
 749          * Make sure delta_sibling is sorted in the original
 750          * recency order.
 751          */
 752         for (i = to_pack.nr_objects; i > 0;) {
 753                 struct object_entry *e = &objects[--i];
 754                 if (!DELTA(e))
 755                         continue;
 756                 /* Mark me as the first child */
 757                 e->delta_sibling_idx = DELTA(e)->delta_child_idx;
 758                 SET_DELTA_CHILD(DELTA(e), e);
 759         }
 760
 761         /*
 762          * Mark objects that are at the tip of tags.
 763          */
 764         for_each_tag_ref(mark_tagged, NULL);
 765
 766         if (use_delta_islands)
 767                 max_layers = compute_pack_layers(&to_pack);
 768
 769         ALLOC_ARRAY(wo, to_pack.nr_objects);
 770         wo_end = 0;
 771
 772         for (; write_layer < max_layers; ++write_layer)
 773                 compute_layer_order(wo, &wo_end);
 774
 775         if (wo_end != to_pack.nr_objects)
 776                 die(_("ordered %u objects, expected %"PRIu32),
 777                     wo_end, to_pack.nr_objects);
 778
 779         return wo;
 780 }
 781
 782 static off_t write_reused_pack(struct hashfile *f)
 783 {
 784         unsigned char buffer[8192];
 785         off_t to_write, total;
 786         int fd;
 787
 788         if (!is_pack_valid(reuse_packfile))
 789                 die(_("packfile is invalid: %s"), reuse_packfile->pack_name);
 790
 791         fd = git_open(reuse_packfile->pack_name);
 792         if (fd < 0)
 793                 die_errno(_("unable to open packfile for reuse: %s"),
 794                           reuse_packfile->pack_name);
 795
 796         if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
 797                 die_errno(_("unable to seek in reused packfile"));
 798
 799         if (reuse_packfile_offset < 0)
 800                 reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
 801
 802         total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 803
 804         while (to_write) {
 805                 int read_pack = xread(fd, buffer, sizeof(buffer));
 806
 807                 if (read_pack <= 0)
 808                         die_errno(_("unable to read from reused packfile"));
 809
 810                 if (read_pack > to_write)
 811                         read_pack = to_write;
 812
 813                 hashwrite(f, buffer, read_pack);
 814                 to_write -= read_pack;
 815
 816                 /*
 817                  * We don't know the actual number of objects written,
 818                  * only how many bytes written, how many bytes total, and
 819                  * how many objects total. So we can fake it by pretending all
 820                  * objects we are writing are the same size. This gives us a
 821                  * smooth progress meter, and at the end it matches the true
 822                  * answer.
 823                  */
 824                 written = reuse_packfile_objects *
 825                                 (((double)(total - to_write)) / total);
 826                 display_progress(progress_state, written);
 827         }
 828
 829         close(fd);
 830         written = reuse_packfile_objects;
 831         display_progress(progress_state, written);
 832         return reuse_packfile_offset - sizeof(struct pack_header);
 833 }
 834
 835 static const char no_split_warning[] = N_(
 836 "disabling bitmap writing, packs are split due to pack.packSizeLimit"
 837 );
 838
 839 static void write_pack_file(void)
 840 {
 841         uint32_t i = 0, j;
 842         struct hashfile *f;
 843         off_t offset;
 844         uint32_t nr_remaining = nr_result;
 845         time_t last_mtime = 0;
 846         struct object_entry **write_order;
 847
 848         if (progress > pack_to_stdout)
 849                 progress_state = start_progress(_("Writing objects"), nr_result);
 850         ALLOC_ARRAY(written_list, to_pack.nr_objects);
 851         write_order = compute_write_order();
 852
 853         do {
 854                 struct object_id oid;
 855                 char *pack_tmp_name = NULL;
 856
 857                 if (pack_to_stdout)
 858                         f = hashfd_throughput(1, "<stdout>", progress_state);
 859                 else
 860                         f = create_tmp_packfile(&pack_tmp_name);
 861
 862                 offset = write_pack_header(f, nr_remaining);
 863
 864                 if (reuse_packfile) {
 865                         off_t packfile_size;
 866                         assert(pack_to_stdout);
 867
 868                         packfile_size = write_reused_pack(f);
 869                         offset += packfile_size;
 870                 }
 871
 872                 nr_written = 0;
 873                 for (; i < to_pack.nr_objects; i++) {
 874                         struct object_entry *e = write_order[i];
 875                         if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 876                                 break;
 877                         display_progress(progress_state, written);
 878                 }
 879
 880                 /*
 881                  * Did we write the wrong # entries in the header?
 882                  * If so, rewrite it like in fast-import
 883                  */
 884                 if (pack_to_stdout) {
 885                         finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_CLOSE);
 886                 } else if (nr_written == nr_remaining) {
 887                         finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 888                 } else {
 889                         int fd = finalize_hashfile(f, oid.hash, 0);
 890                         fixup_pack_header_footer(fd, oid.hash, pack_tmp_name,
 891                                                  nr_written, oid.hash, offset);
 892                         close(fd);
 893                         if (write_bitmap_index) {
 894                                 warning(_(no_split_warning));
 895                                 write_bitmap_index = 0;
 896                         }
 897                 }
 898
 899                 if (!pack_to_stdout) {
 900                         struct stat st;
 901                         struct strbuf tmpname = STRBUF_INIT;
 902
 903                         /*
 904                          * Packs are runtime accessed in their mtime
 905                          * order since newer packs are more likely to contain
 906                          * younger objects.  So if we are creating multiple
 907                          * packs then we should modify the mtime of later ones
 908                          * to preserve this property.
 909                          */
 910                         if (stat(pack_tmp_name, &st) < 0) {
 911                                 warning_errno(_("failed to stat %s"), pack_tmp_name);
 912                         } else if (!last_mtime) {
 913                                 last_mtime = st.st_mtime;
 914                         } else {
 915                                 struct utimbuf utb;
 916                                 utb.actime = st.st_atime;
 917                                 utb.modtime = --last_mtime;
 918                                 if (utime(pack_tmp_name, &utb) < 0)
 919                                         warning_errno(_("failed utime() on %s"), pack_tmp_name);
 920                         }
 921
 922                         strbuf_addf(&tmpname, "%s-", base_name);
 923
 924                         if (write_bitmap_index) {
 925                                 bitmap_writer_set_checksum(oid.hash);
 926                                 bitmap_writer_build_type_index(
 927                                         &to_pack, written_list, nr_written);
 928                         }
 929
 930                         finish_tmp_packfile(&tmpname, pack_tmp_name,
 931                                             written_list, nr_written,
 932                                             &pack_idx_opts, oid.hash);
 933
 934                         if (write_bitmap_index) {
 935                                 strbuf_addf(&tmpname, "%s.bitmap", oid_to_hex(&oid));
 936
 937                                 stop_progress(&progress_state);
 938
 939                                 bitmap_writer_show_progress(progress);
 940                                 bitmap_writer_reuse_bitmaps(&to_pack);
 941                                 bitmap_writer_select_commits(indexed_commits, indexed_commits_nr, -1);
 942                                 bitmap_writer_build(&to_pack);
 943                                 bitmap_writer_finish(written_list, nr_written,
 944                                                      tmpname.buf, write_bitmap_options);
 945                                 write_bitmap_index = 0;
 946                         }
 947
 948                         strbuf_release(&tmpname);
 949                         free(pack_tmp_name);
 950                         puts(oid_to_hex(&oid));
 951                 }
 952
 953                 /* mark written objects as written to previous pack */
 954                 for (j = 0; j < nr_written; j++) {
 955                         written_list[j]->offset = (off_t)-1;
 956                 }
 957                 nr_remaining -= nr_written;
 958         } while (nr_remaining && i < to_pack.nr_objects);
 959
 960         free(written_list);
 961         free(write_order);
 962         stop_progress(&progress_state);
 963         if (written != nr_result)
 964                 die(_("wrote %"PRIu32" objects while expecting %"PRIu32),
 965                     written, nr_result);
 966 }
 967
 968 static int no_try_delta(const char *path)
 969 {
 970         static struct attr_check *check;
 971
 972         if (!check)
 973                 check = attr_check_initl("delta", NULL);
 974         git_check_attr(the_repository->index, path, check);
 975         if (ATTR_FALSE(check->items[0].value))
 976                 return 1;
 977         return 0;
 978 }
 979
 980 /*
 981  * When adding an object, check whether we have already added it
 982  * to our packing list. If so, we can skip. However, if we are
 983  * being asked to excludei t, but the previous mention was to include
 984  * it, make sure to adjust its flags and tweak our numbers accordingly.
 985  *
 986  * As an optimization, we pass out the index position where we would have
 987  * found the item, since that saves us from having to look it up again a
 988  * few lines later when we want to add the new entry.
 989  */
 990 static int have_duplicate_entry(const struct object_id *oid,
 991                                 int exclude,
 992                                 uint32_t *index_pos)
 993 {
 994         struct object_entry *entry;
 995
 996         entry = packlist_find(&to_pack, oid->hash, index_pos);
 997         if (!entry)
 998                 return 0;
 999
1000         if (exclude) {
1001                 if (!entry->preferred_base)
1002                         nr_result--;
1003                 entry->preferred_base = 1;
1004         }
1005
1006         return 1;
1007 }
1008
1009 static int want_found_object(int exclude, struct packed_git *p)
1010 {
1011         if (exclude)
1012                 return 1;
1013         if (incremental)
1014                 return 0;
1015
1016         /*
1017          * When asked to do --local (do not include an object that appears in a
1018          * pack we borrow from elsewhere) or --honor-pack-keep (do not include
1019          * an object that appears in a pack marked with .keep), finding a pack
1020          * that matches the criteria is sufficient for us to decide to omit it.
1021          * However, even if this pack does not satisfy the criteria, we need to
1022          * make sure no copy of this object appears in _any_ pack that makes us
1023          * to omit the object, so we need to check all the packs.
1024          *
1025          * We can however first check whether these options can possible matter;
1026          * if they do not matter we know we want the object in generated pack.
1027          * Otherwise, we signal "-1" at the end to tell the caller that we do
1028          * not know either way, and it needs to check more packs.
1029          */
1030         if (!ignore_packed_keep_on_disk &&
1031             !ignore_packed_keep_in_core &&
1032             (!local || !have_non_local_packs))
1033                 return 1;
1034
1035         if (local && !p->pack_local)
1036                 return 0;
1037         if (p->pack_local &&
1038             ((ignore_packed_keep_on_disk && p->pack_keep) ||
1039              (ignore_packed_keep_in_core && p->pack_keep_in_core)))
1040                 return 0;
1041
1042         /* we don't know yet; keep looking for more packs */
1043         return -1;
1044 }
1045
1046 /*
1047  * Check whether we want the object in the pack (e.g., we do not want
1048  * objects found in non-local stores if the "--local" option was used).
1049  *
1050  * If the caller already knows an existing pack it wants to take the object
1051  * from, that is passed in *found_pack and *found_offset; otherwise this
1052  * function finds if there is any pack that has the object and returns the pack
1053  * and its offset in these variables.
1054  */
1055 static int want_object_in_pack(const struct object_id *oid,
1056                                int exclude,
1057                                struct packed_git **found_pack,
1058                                off_t *found_offset)
1059 {
1060         int want;
1061         struct list_head *pos;
1062         struct multi_pack_index *m;
1063
1064         if (!exclude && local && has_loose_object_nonlocal(oid))
1065                 return 0;
1066
1067         /*
1068          * If we already know the pack object lives in, start checks from that
1069          * pack - in the usual case when neither --local was given nor .keep files
1070          * are present we will determine the answer right now.
1071          */
1072         if (*found_pack) {
1073                 want = want_found_object(exclude, *found_pack);
1074                 if (want != -1)
1075                         return want;
1076         }
1077
1078         for (m = get_multi_pack_index(the_repository); m; m = m->next) {
1079                 struct pack_entry e;
1080                 if (fill_midx_entry(oid, &e, m)) {
1081                         struct packed_git *p = e.p;
1082                         off_t offset;
1083
1084                         if (p == *found_pack)
1085                                 offset = *found_offset;
1086                         else
1087                                 offset = find_pack_entry_one(oid->hash, p);
1088
1089                         if (offset) {
1090                                 if (!*found_pack) {
1091                                         if (!is_pack_valid(p))
1092                                                 continue;
1093                                         *found_offset = offset;
1094                                         *found_pack = p;
1095                                 }
1096                                 want = want_found_object(exclude, p);
1097                                 if (want != -1)
1098                                         return want;
1099                         }
1100                 }
1101         }
1102
1103         list_for_each(pos, get_packed_git_mru(the_repository)) {
1104                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
1105                 off_t offset;
1106
1107                 if (p == *found_pack)
1108                         offset = *found_offset;
1109                 else
1110                         offset = find_pack_entry_one(oid->hash, p);
1111
1112                 if (offset) {
1113                         if (!*found_pack) {
1114                                 if (!is_pack_valid(p))
1115                                         continue;
1116                                 *found_offset = offset;
1117                                 *found_pack = p;
1118                         }
1119                         want = want_found_object(exclude, p);
1120                         if (!exclude && want > 0)
1121                                 list_move(&p->mru,
1122                                           get_packed_git_mru(the_repository));
1123                         if (want != -1)
1124                                 return want;
1125                 }
1126         }
1127
1128         return 1;
1129 }
1130
1131 static void create_object_entry(const struct object_id *oid,
1132                                 enum object_type type,
1133                                 uint32_t hash,
1134                                 int exclude,
1135                                 int no_try_delta,
1136                                 uint32_t index_pos,
1137                                 struct packed_git *found_pack,
1138                                 off_t found_offset)
1139 {
1140         struct object_entry *entry;
1141
1142         entry = packlist_alloc(&to_pack, oid->hash, index_pos);
1143         entry->hash = hash;
1144         oe_set_type(entry, type);
1145         if (exclude)
1146                 entry->preferred_base = 1;
1147         else
1148                 nr_result++;
1149         if (found_pack) {
1150                 oe_set_in_pack(&to_pack, entry, found_pack);
1151                 entry->in_pack_offset = found_offset;
1152         }
1153
1154         entry->no_try_delta = no_try_delta;
1155 }
1156
1157 static const char no_closure_warning[] = N_(
1158 "disabling bitmap writing, as some objects are not being packed"
1159 );
1160
1161 static int add_object_entry(const struct object_id *oid, enum object_type type,
1162                             const char *name, int exclude)
1163 {
1164         struct packed_git *found_pack = NULL;
1165         off_t found_offset = 0;
1166         uint32_t index_pos;
1167
1168         display_progress(progress_state, ++nr_seen);
1169
1170         if (have_duplicate_entry(oid, exclude, &index_pos))
1171                 return 0;
1172
1173         if (!want_object_in_pack(oid, exclude, &found_pack, &found_offset)) {
1174                 /* The pack is missing an object, so it will not have closure */
1175                 if (write_bitmap_index) {
1176                         warning(_(no_closure_warning));
1177                         write_bitmap_index = 0;
1178                 }
1179                 return 0;
1180         }
1181
1182         create_object_entry(oid, type, pack_name_hash(name),
1183                             exclude, name && no_try_delta(name),
1184                             index_pos, found_pack, found_offset);
1185         return 1;
1186 }
1187
1188 static int add_object_entry_from_bitmap(const struct object_id *oid,
1189                                         enum object_type type,
1190                                         int flags, uint32_t name_hash,
1191                                         struct packed_git *pack, off_t offset)
1192 {
1193         uint32_t index_pos;
1194
1195         display_progress(progress_state, ++nr_seen);
1196
1197         if (have_duplicate_entry(oid, 0, &index_pos))
1198                 return 0;
1199
1200         if (!want_object_in_pack(oid, 0, &pack, &offset))
1201                 return 0;
1202
1203         create_object_entry(oid, type, name_hash, 0, 0, index_pos, pack, offset);
1204         return 1;
1205 }
1206
1207 struct pbase_tree_cache {
1208         struct object_id oid;
1209         int ref;
1210         int temporary;
1211         void *tree_data;
1212         unsigned long tree_size;
1213 };
1214
1215 static struct pbase_tree_cache *(pbase_tree_cache[256]);
1216 static int pbase_tree_cache_ix(const struct object_id *oid)
1217 {
1218         return oid->hash[0] % ARRAY_SIZE(pbase_tree_cache);
1219 }
1220 static int pbase_tree_cache_ix_incr(int ix)
1221 {
1222         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
1223 }
1224
1225 static struct pbase_tree {
1226         struct pbase_tree *next;
1227         /* This is a phony "cache" entry; we are not
1228          * going to evict it or find it through _get()
1229          * mechanism -- this is for the toplevel node that
1230          * would almost always change with any commit.
1231          */
1232         struct pbase_tree_cache pcache;
1233 } *pbase_tree;
1234
1235 static struct pbase_tree_cache *pbase_tree_get(const struct object_id *oid)
1236 {
1237         struct pbase_tree_cache *ent, *nent;
1238         void *data;
1239         unsigned long size;
1240         enum object_type type;
1241         int neigh;
1242         int my_ix = pbase_tree_cache_ix(oid);
1243         int available_ix = -1;
1244
1245         /* pbase-tree-cache acts as a limited hashtable.
1246          * your object will be found at your index or within a few
1247          * slots after that slot if it is cached.
1248          */
1249         for (neigh = 0; neigh < 8; neigh++) {
1250                 ent = pbase_tree_cache[my_ix];
1251                 if (ent && oideq(&ent->oid, oid)) {
1252                         ent->ref++;
1253                         return ent;
1254                 }
1255                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
1256                          ((0 <= available_ix) &&
1257                           (!ent && pbase_tree_cache[available_ix])))
1258                         available_ix = my_ix;
1259                 if (!ent)
1260                         break;
1261                 my_ix = pbase_tree_cache_ix_incr(my_ix);
1262         }
1263
1264         /* Did not find one.  Either we got a bogus request or
1265          * we need to read and perhaps cache.
1266          */
1267         data = read_object_file(oid, &type, &size);
1268         if (!data)
1269                 return NULL;
1270         if (type != OBJ_TREE) {
1271                 free(data);
1272                 return NULL;
1273         }
1274
1275         /* We need to either cache or return a throwaway copy */
1276
1277         if (available_ix < 0)
1278                 ent = NULL;
1279         else {
1280                 ent = pbase_tree_cache[available_ix];
1281                 my_ix = available_ix;
1282         }
1283
1284         if (!ent) {
1285                 nent = xmalloc(sizeof(*nent));
1286                 nent->temporary = (available_ix < 0);
1287         }
1288         else {
1289                 /* evict and reuse */
1290                 free(ent->tree_data);
1291                 nent = ent;
1292         }
1293         oidcpy(&nent->oid, oid);
1294         nent->tree_data = data;
1295         nent->tree_size = size;
1296         nent->ref = 1;
1297         if (!nent->temporary)
1298                 pbase_tree_cache[my_ix] = nent;
1299         return nent;
1300 }
1301
1302 static void pbase_tree_put(struct pbase_tree_cache *cache)
1303 {
1304         if (!cache->temporary) {
1305                 cache->ref--;
1306                 return;
1307         }
1308         free(cache->tree_data);
1309         free(cache);
1310 }
1311
1312 static int name_cmp_len(const char *name)
1313 {
1314         int i;
1315         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1316                 ;
1317         return i;
1318 }
1319
1320 static void add_pbase_object(struct tree_desc *tree,
1321                              const char *name,
1322                              int cmplen,
1323                              const char *fullname)
1324 {
1325         struct name_entry entry;
1326         int cmp;
1327
1328         while (tree_entry(tree,&entry)) {
1329                 if (S_ISGITLINK(entry.mode))
1330                         continue;
1331                 cmp = tree_entry_len(&entry) != cmplen ? 1 :
1332                       memcmp(name, entry.path, cmplen);
1333                 if (cmp > 0)
1334                         continue;
1335                 if (cmp < 0)
1336                         return;
1337                 if (name[cmplen] != '/') {
1338                         add_object_entry(&entry.oid,
1339                                          object_type(entry.mode),
1340                                          fullname, 1);
1341                         return;
1342                 }
1343                 if (S_ISDIR(entry.mode)) {
1344                         struct tree_desc sub;
1345                         struct pbase_tree_cache *tree;
1346                         const char *down = name+cmplen+1;
1347                         int downlen = name_cmp_len(down);
1348
1349                         tree = pbase_tree_get(&entry.oid);
1350                         if (!tree)
1351                                 return;
1352                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1353
1354                         add_pbase_object(&sub, down, downlen, fullname);
1355                         pbase_tree_put(tree);
1356                 }
1357         }
1358 }
1359
1360 static unsigned *done_pbase_paths;
1361 static int done_pbase_paths_num;
1362 static int done_pbase_paths_alloc;
1363 static int done_pbase_path_pos(unsigned hash)
1364 {
1365         int lo = 0;
1366         int hi = done_pbase_paths_num;
1367         while (lo < hi) {
1368                 int mi = lo + (hi - lo) / 2;
1369                 if (done_pbase_paths[mi] == hash)
1370                         return mi;
1371                 if (done_pbase_paths[mi] < hash)
1372                         hi = mi;
1373                 else
1374                         lo = mi + 1;
1375         }
1376         return -lo-1;
1377 }
1378
1379 static int check_pbase_path(unsigned hash)
1380 {
1381         int pos = done_pbase_path_pos(hash);
1382         if (0 <= pos)
1383                 return 1;
1384         pos = -pos - 1;
1385         ALLOC_GROW(done_pbase_paths,
1386                    done_pbase_paths_num + 1,
1387                    done_pbase_paths_alloc);
1388         done_pbase_paths_num++;
1389         if (pos < done_pbase_paths_num)
1390                 MOVE_ARRAY(done_pbase_paths + pos + 1, done_pbase_paths + pos,
1391                            done_pbase_paths_num - pos - 1);
1392         done_pbase_paths[pos] = hash;
1393         return 0;
1394 }
1395
1396 static void add_preferred_base_object(const char *name)
1397 {
1398         struct pbase_tree *it;
1399         int cmplen;
1400         unsigned hash = pack_name_hash(name);
1401
1402         if (!num_preferred_base || check_pbase_path(hash))
1403                 return;
1404
1405         cmplen = name_cmp_len(name);
1406         for (it = pbase_tree; it; it = it->next) {
1407                 if (cmplen == 0) {
1408                         add_object_entry(&it->pcache.oid, OBJ_TREE, NULL, 1);
1409                 }
1410                 else {
1411                         struct tree_desc tree;
1412                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1413                         add_pbase_object(&tree, name, cmplen, name);
1414                 }
1415         }
1416 }
1417
1418 static void add_preferred_base(struct object_id *oid)
1419 {
1420         struct pbase_tree *it;
1421         void *data;
1422         unsigned long size;
1423         struct object_id tree_oid;
1424
1425         if (window <= num_preferred_base++)
1426                 return;
1427
1428         data = read_object_with_reference(oid, tree_type, &size, &tree_oid);
1429         if (!data)
1430                 return;
1431
1432         for (it = pbase_tree; it; it = it->next) {
1433                 if (oideq(&it->pcache.oid, &tree_oid)) {
1434                         free(data);
1435                         return;
1436                 }
1437         }
1438
1439         it = xcalloc(1, sizeof(*it));
1440         it->next = pbase_tree;
1441         pbase_tree = it;
1442
1443         oidcpy(&it->pcache.oid, &tree_oid);
1444         it->pcache.tree_data = data;
1445         it->pcache.tree_size = size;
1446 }
1447
1448 static void cleanup_preferred_base(void)
1449 {
1450         struct pbase_tree *it;
1451         unsigned i;
1452
1453         it = pbase_tree;
1454         pbase_tree = NULL;
1455         while (it) {
1456                 struct pbase_tree *tmp = it;
1457                 it = tmp->next;
1458                 free(tmp->pcache.tree_data);
1459                 free(tmp);
1460         }
1461
1462         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1463                 if (!pbase_tree_cache[i])
1464                         continue;
1465                 free(pbase_tree_cache[i]->tree_data);
1466                 FREE_AND_NULL(pbase_tree_cache[i]);
1467         }
1468
1469         FREE_AND_NULL(done_pbase_paths);
1470         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1471 }
1472
1473 /*
1474  * Return 1 iff the object specified by "delta" can be sent
1475  * literally as a delta against the base in "base_sha1". If
1476  * so, then *base_out will point to the entry in our packing
1477  * list, or NULL if we must use the external-base list.
1478  *
1479  * Depth value does not matter - find_deltas() will
1480  * never consider reused delta as the base object to
1481  * deltify other objects against, in order to avoid
1482  * circular deltas.
1483  */
1484 static int can_reuse_delta(const unsigned char *base_sha1,
1485                            struct object_entry *delta,
1486                            struct object_entry **base_out)
1487 {
1488         struct object_entry *base;
1489
1490         if (!base_sha1)
1491                 return 0;
1492
1493         /*
1494          * First see if we're already sending the base (or it's explicitly in
1495          * our "excluded" list).
1496          */
1497         base = packlist_find(&to_pack, base_sha1, NULL);
1498         if (base) {
1499                 if (!in_same_island(&delta->idx.oid, &base->idx.oid))
1500                         return 0;
1501                 *base_out = base;
1502                 return 1;
1503         }
1504
1505         /*
1506          * Otherwise, reachability bitmaps may tell us if the receiver has it,
1507          * even if it was buried too deep in history to make it into the
1508          * packing list.
1509          */
1510         if (thin && bitmap_has_sha1_in_uninteresting(bitmap_git, base_sha1)) {
1511                 if (use_delta_islands) {
1512                         struct object_id base_oid;
1513                         hashcpy(base_oid.hash, base_sha1);
1514                         if (!in_same_island(&delta->idx.oid, &base_oid))
1515                                 return 0;
1516                 }
1517                 *base_out = NULL;
1518                 return 1;
1519         }
1520
1521         return 0;
1522 }
1523
1524 static void check_object(struct object_entry *entry)
1525 {
1526         unsigned long canonical_size;
1527
1528         if (IN_PACK(entry)) {
1529                 struct packed_git *p = IN_PACK(entry);
1530                 struct pack_window *w_curs = NULL;
1531                 const unsigned char *base_ref = NULL;
1532                 struct object_entry *base_entry;
1533                 unsigned long used, used_0;
1534                 unsigned long avail;
1535                 off_t ofs;
1536                 unsigned char *buf, c;
1537                 enum object_type type;
1538                 unsigned long in_pack_size;
1539
1540                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1541
1542                 /*
1543                  * We want in_pack_type even if we do not reuse delta
1544                  * since non-delta representations could still be reused.
1545                  */
1546                 used = unpack_object_header_buffer(buf, avail,
1547                                                    &type,
1548                                                    &in_pack_size);
1549                 if (used == 0)
1550                         goto give_up;
1551
1552                 if (type < 0)
1553                         BUG("invalid type %d", type);
1554                 entry->in_pack_type = type;
1555
1556                 /*
1557                  * Determine if this is a delta and if so whether we can
1558                  * reuse it or not.  Otherwise let's find out as cheaply as
1559                  * possible what the actual type and size for this object is.
1560                  */
1561                 switch (entry->in_pack_type) {
1562                 default:
1563                         /* Not a delta hence we've already got all we need. */
1564                         oe_set_type(entry, entry->in_pack_type);
1565                         SET_SIZE(entry, in_pack_size);
1566                         entry->in_pack_header_size = used;
1567                         if (oe_type(entry) < OBJ_COMMIT || oe_type(entry) > OBJ_BLOB)
1568                                 goto give_up;
1569                         unuse_pack(&w_curs);
1570                         return;
1571                 case OBJ_REF_DELTA:
1572                         if (reuse_delta && !entry->preferred_base)
1573                                 base_ref = use_pack(p, &w_curs,
1574                                                 entry->in_pack_offset + used, NULL);
1575                         entry->in_pack_header_size = used + the_hash_algo->rawsz;
1576                         break;
1577                 case OBJ_OFS_DELTA:
1578                         buf = use_pack(p, &w_curs,
1579                                        entry->in_pack_offset + used, NULL);
1580                         used_0 = 0;
1581                         c = buf[used_0++];
1582                         ofs = c & 127;
1583                         while (c & 128) {
1584                                 ofs += 1;
1585                                 if (!ofs || MSB(ofs, 7)) {
1586                                         error(_("delta base offset overflow in pack for %s"),
1587                                               oid_to_hex(&entry->idx.oid));
1588                                         goto give_up;
1589                                 }
1590                                 c = buf[used_0++];
1591                                 ofs = (ofs << 7) + (c & 127);
1592                         }
1593                         ofs = entry->in_pack_offset - ofs;
1594                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1595                                 error(_("delta base offset out of bound for %s"),
1596                                       oid_to_hex(&entry->idx.oid));
1597                                 goto give_up;
1598                         }
1599                         if (reuse_delta && !entry->preferred_base) {
1600                                 struct revindex_entry *revidx;
1601                                 revidx = find_pack_revindex(p, ofs);
1602                                 if (!revidx)
1603                                         goto give_up;
1604                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1605                         }
1606                         entry->in_pack_header_size = used + used_0;
1607                         break;
1608                 }
1609
1610                 if (can_reuse_delta(base_ref, entry, &base_entry)) {
1611                         oe_set_type(entry, entry->in_pack_type);
1612                         SET_SIZE(entry, in_pack_size); /* delta size */
1613                         SET_DELTA_SIZE(entry, in_pack_size);
1614
1615                         if (base_entry) {
1616                                 SET_DELTA(entry, base_entry);
1617                                 entry->delta_sibling_idx = base_entry->delta_child_idx;
1618                                 SET_DELTA_CHILD(base_entry, entry);
1619                         } else {
1620                                 SET_DELTA_EXT(entry, base_ref);
1621                         }
1622
1623                         unuse_pack(&w_curs);
1624                         return;
1625                 }
1626
1627                 if (oe_type(entry)) {
1628                         off_t delta_pos;
1629
1630                         /*
1631                          * This must be a delta and we already know what the
1632                          * final object type is.  Let's extract the actual
1633                          * object size from the delta header.
1634                          */
1635                         delta_pos = entry->in_pack_offset + entry->in_pack_header_size;
1636                         canonical_size = get_size_from_delta(p, &w_curs, delta_pos);
1637                         if (canonical_size == 0)
1638                                 goto give_up;
1639                         SET_SIZE(entry, canonical_size);
1640                         unuse_pack(&w_curs);
1641                         return;
1642                 }
1643
1644                 /*
1645                  * No choice but to fall back to the recursive delta walk
1646                  * with oid_object_info() to find about the object type
1647                  * at this point...
1648                  */
1649                 give_up:
1650                 unuse_pack(&w_curs);
1651         }
1652
1653         oe_set_type(entry,
1654                     oid_object_info(the_repository, &entry->idx.oid, &canonical_size));
1655         if (entry->type_valid) {
1656                 SET_SIZE(entry, canonical_size);
1657         } else {
1658                 /*
1659                  * Bad object type is checked in prepare_pack().  This is
1660                  * to permit a missing preferred base object to be ignored
1661                  * as a preferred base.  Doing so can result in a larger
1662                  * pack file, but the transfer will still take place.
1663                  */
1664         }
1665 }
1666
1667 static int pack_offset_sort(const void *_a, const void *_b)
1668 {
1669         const struct object_entry *a = *(struct object_entry **)_a;
1670         const struct object_entry *b = *(struct object_entry **)_b;
1671         const struct packed_git *a_in_pack = IN_PACK(a);
1672         const struct packed_git *b_in_pack = IN_PACK(b);
1673
1674         /* avoid filesystem trashing with loose objects */
1675         if (!a_in_pack && !b_in_pack)
1676                 return oidcmp(&a->idx.oid, &b->idx.oid);
1677
1678         if (a_in_pack < b_in_pack)
1679                 return -1;
1680         if (a_in_pack > b_in_pack)
1681                 return 1;
1682         return a->in_pack_offset < b->in_pack_offset ? -1 :
1683                         (a->in_pack_offset > b->in_pack_offset);
1684 }
1685
1686 /*
1687  * Drop an on-disk delta we were planning to reuse. Naively, this would
1688  * just involve blanking out the "delta" field, but we have to deal
1689  * with some extra book-keeping:
1690  *
1691  *   1. Removing ourselves from the delta_sibling linked list.
1692  *
1693  *   2. Updating our size/type to the non-delta representation. These were
1694  *      either not recorded initially (size) or overwritten with the delta type
1695  *      (type) when check_object() decided to reuse the delta.
1696  *
1697  *   3. Resetting our delta depth, as we are now a base object.
1698  */
1699 static void drop_reused_delta(struct object_entry *entry)
1700 {
1701         unsigned *idx = &to_pack.objects[entry->delta_idx - 1].delta_child_idx;
1702         struct object_info oi = OBJECT_INFO_INIT;
1703         enum object_type type;
1704         unsigned long size;
1705
1706         while (*idx) {
1707                 struct object_entry *oe = &to_pack.objects[*idx - 1];
1708
1709                 if (oe == entry)
1710                         *idx = oe->delta_sibling_idx;
1711                 else
1712                         idx = &oe->delta_sibling_idx;
1713         }
1714         SET_DELTA(entry, NULL);
1715         entry->depth = 0;
1716
1717         oi.sizep = &size;
1718         oi.typep = &type;
1719         if (packed_object_info(the_repository, IN_PACK(entry), entry->in_pack_offset, &oi) < 0) {
1720                 /*
1721                  * We failed to get the info from this pack for some reason;
1722                  * fall back to oid_object_info, which may find another copy.
1723                  * And if that fails, the error will be recorded in oe_type(entry)
1724                  * and dealt with in prepare_pack().
1725                  */
1726                 oe_set_type(entry,
1727                             oid_object_info(the_repository, &entry->idx.oid, &size));
1728         } else {
1729                 oe_set_type(entry, type);
1730         }
1731         SET_SIZE(entry, size);
1732 }
1733
1734 /*
1735  * Follow the chain of deltas from this entry onward, throwing away any links
1736  * that cause us to hit a cycle (as determined by the DFS state flags in
1737  * the entries).
1738  *
1739  * We also detect too-long reused chains that would violate our --depth
1740  * limit.
1741  */
1742 static void break_delta_chains(struct object_entry *entry)
1743 {
1744         /*
1745          * The actual depth of each object we will write is stored as an int,
1746          * as it cannot exceed our int "depth" limit. But before we break
1747          * changes based no that limit, we may potentially go as deep as the
1748          * number of objects, which is elsewhere bounded to a uint32_t.
1749          */
1750         uint32_t total_depth;
1751         struct object_entry *cur, *next;
1752
1753         for (cur = entry, total_depth = 0;
1754              cur;
1755              cur = DELTA(cur), total_depth++) {
1756                 if (cur->dfs_state == DFS_DONE) {
1757                         /*
1758                          * We've already seen this object and know it isn't
1759                          * part of a cycle. We do need to append its depth
1760                          * to our count.
1761                          */
1762                         total_depth += cur->depth;
1763                         break;
1764                 }
1765
1766                 /*
1767                  * We break cycles before looping, so an ACTIVE state (or any
1768                  * other cruft which made its way into the state variable)
1769                  * is a bug.
1770                  */
1771                 if (cur->dfs_state != DFS_NONE)
1772                         BUG("confusing delta dfs state in first pass: %d",
1773                             cur->dfs_state);
1774
1775                 /*
1776                  * Now we know this is the first time we've seen the object. If
1777                  * it's not a delta, we're done traversing, but we'll mark it
1778                  * done to save time on future traversals.
1779                  */
1780                 if (!DELTA(cur)) {
1781                         cur->dfs_state = DFS_DONE;
1782                         break;
1783                 }
1784
1785                 /*
1786                  * Mark ourselves as active and see if the next step causes
1787                  * us to cycle to another active object. It's important to do
1788                  * this _before_ we loop, because it impacts where we make the
1789                  * cut, and thus how our total_depth counter works.
1790                  * E.g., We may see a partial loop like:
1791                  *
1792                  *   A -> B -> C -> D -> B
1793                  *
1794                  * Cutting B->C breaks the cycle. But now the depth of A is
1795                  * only 1, and our total_depth counter is at 3. The size of the
1796                  * error is always one less than the size of the cycle we
1797                  * broke. Commits C and D were "lost" from A's chain.
1798                  *
1799                  * If we instead cut D->B, then the depth of A is correct at 3.
1800                  * We keep all commits in the chain that we examined.
1801                  */
1802                 cur->dfs_state = DFS_ACTIVE;
1803                 if (DELTA(cur)->dfs_state == DFS_ACTIVE) {
1804                         drop_reused_delta(cur);
1805                         cur->dfs_state = DFS_DONE;
1806                         break;
1807                 }
1808         }
1809
1810         /*
1811          * And now that we've gone all the way to the bottom of the chain, we
1812          * need to clear the active flags and set the depth fields as
1813          * appropriate. Unlike the loop above, which can quit when it drops a
1814          * delta, we need to keep going to look for more depth cuts. So we need
1815          * an extra "next" pointer to keep going after we reset cur->delta.
1816          */
1817         for (cur = entry; cur; cur = next) {
1818                 next = DELTA(cur);
1819
1820                 /*
1821                  * We should have a chain of zero or more ACTIVE states down to
1822                  * a final DONE. We can quit after the DONE, because either it
1823                  * has no bases, or we've already handled them in a previous
1824                  * call.
1825                  */
1826                 if (cur->dfs_state == DFS_DONE)
1827                         break;
1828                 else if (cur->dfs_state != DFS_ACTIVE)
1829                         BUG("confusing delta dfs state in second pass: %d",
1830                             cur->dfs_state);
1831
1832                 /*
1833                  * If the total_depth is more than depth, then we need to snip
1834                  * the chain into two or more smaller chains that don't exceed
1835                  * the maximum depth. Most of the resulting chains will contain
1836                  * (depth + 1) entries (i.e., depth deltas plus one base), and
1837                  * the last chain (i.e., the one containing entry) will contain
1838                  * whatever entries are left over, namely
1839                  * (total_depth % (depth + 1)) of them.
1840                  *
1841                  * Since we are iterating towards decreasing depth, we need to
1842                  * decrement total_depth as we go, and we need to write to the
1843                  * entry what its final depth will be after all of the
1844                  * snipping. Since we're snipping into chains of length (depth
1845                  * + 1) entries, the final depth of an entry will be its
1846                  * original depth modulo (depth + 1). Any time we encounter an
1847                  * entry whose final depth is supposed to be zero, we snip it
1848                  * from its delta base, thereby making it so.
1849                  */
1850                 cur->depth = (total_depth--) % (depth + 1);
1851                 if (!cur->depth)
1852                         drop_reused_delta(cur);
1853
1854                 cur->dfs_state = DFS_DONE;
1855         }
1856 }
1857
1858 static void get_object_details(void)
1859 {
1860         uint32_t i;
1861         struct object_entry **sorted_by_offset;
1862
1863         if (progress)
1864                 progress_state = start_progress(_("Counting objects"),
1865                                                 to_pack.nr_objects);
1866
1867         sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
1868         for (i = 0; i < to_pack.nr_objects; i++)
1869                 sorted_by_offset[i] = to_pack.objects + i;
1870         QSORT(sorted_by_offset, to_pack.nr_objects, pack_offset_sort);
1871
1872         for (i = 0; i < to_pack.nr_objects; i++) {
1873                 struct object_entry *entry = sorted_by_offset[i];
1874                 check_object(entry);
1875                 if (entry->type_valid &&
1876                     oe_size_greater_than(&to_pack, entry, big_file_threshold))
1877                         entry->no_try_delta = 1;
1878                 display_progress(progress_state, i + 1);
1879         }
1880         stop_progress(&progress_state);
1881
1882         /*
1883          * This must happen in a second pass, since we rely on the delta
1884          * information for the whole list being completed.
1885          */
1886         for (i = 0; i < to_pack.nr_objects; i++)
1887                 break_delta_chains(&to_pack.objects[i]);
1888
1889         free(sorted_by_offset);
1890 }
1891
1892 /*
1893  * We search for deltas in a list sorted by type, by filename hash, and then
1894  * by size, so that we see progressively smaller and smaller files.
1895  * That's because we prefer deltas to be from the bigger file
1896  * to the smaller -- deletes are potentially cheaper, but perhaps
1897  * more importantly, the bigger file is likely the more recent
1898  * one.  The deepest deltas are therefore the oldest objects which are
1899  * less susceptible to be accessed often.
1900  */
1901 static int type_size_sort(const void *_a, const void *_b)
1902 {
1903         const struct object_entry *a = *(struct object_entry **)_a;
1904         const struct object_entry *b = *(struct object_entry **)_b;
1905         const enum object_type a_type = oe_type(a);
1906         const enum object_type b_type = oe_type(b);
1907         const unsigned long a_size = SIZE(a);
1908         const unsigned long b_size = SIZE(b);
1909
1910         if (a_type > b_type)
1911                 return -1;
1912         if (a_type < b_type)
1913                 return 1;
1914         if (a->hash > b->hash)
1915                 return -1;
1916         if (a->hash < b->hash)
1917                 return 1;
1918         if (a->preferred_base > b->preferred_base)
1919                 return -1;
1920         if (a->preferred_base < b->preferred_base)
1921                 return 1;
1922         if (use_delta_islands) {
1923                 const int island_cmp = island_delta_cmp(&a->idx.oid, &b->idx.oid);
1924                 if (island_cmp)
1925                         return island_cmp;
1926         }
1927         if (a_size > b_size)
1928                 return -1;
1929         if (a_size < b_size)
1930                 return 1;
1931         return a < b ? -1 : (a > b);  /* newest first */
1932 }
1933
1934 struct unpacked {
1935         struct object_entry *entry;
1936         void *data;
1937         struct delta_index *index;
1938         unsigned depth;
1939 };
1940
1941 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1942                            unsigned long delta_size)
1943 {
1944         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1945                 return 0;
1946
1947         if (delta_size < cache_max_small_delta_size)
1948                 return 1;
1949
1950         /* cache delta, if objects are large enough compared to delta size */
1951         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1952                 return 1;
1953
1954         return 0;
1955 }
1956
1957 /* Protect delta_cache_size */
1958 static pthread_mutex_t cache_mutex;
1959 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1960 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1961
1962 /*
1963  * Protect object list partitioning (e.g. struct thread_param) and
1964  * progress_state
1965  */
1966 static pthread_mutex_t progress_mutex;
1967 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1968 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1969
1970 /*
1971  * Access to struct object_entry is unprotected since each thread owns
1972  * a portion of the main object list. Just don't access object entries
1973  * ahead in the list because they can be stolen and would need
1974  * progress_mutex for protection.
1975  */
1976
1977 /*
1978  * Return the size of the object without doing any delta
1979  * reconstruction (so non-deltas are true object sizes, but deltas
1980  * return the size of the delta data).
1981  */
1982 unsigned long oe_get_size_slow(struct packing_data *pack,
1983                                const struct object_entry *e)
1984 {
1985         struct packed_git *p;
1986         struct pack_window *w_curs;
1987         unsigned char *buf;
1988         enum object_type type;
1989         unsigned long used, avail, size;
1990
1991         if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
1992                 packing_data_lock(&to_pack);
1993                 if (oid_object_info(the_repository, &e->idx.oid, &size) < 0)
1994                         die(_("unable to get size of %s"),
1995                             oid_to_hex(&e->idx.oid));
1996                 packing_data_unlock(&to_pack);
1997                 return size;
1998         }
1999
2000         p = oe_in_pack(pack, e);
2001         if (!p)
2002                 BUG("when e->type is a delta, it must belong to a pack");
2003
2004         packing_data_lock(&to_pack);
2005         w_curs = NULL;
2006         buf = use_pack(p, &w_curs, e->in_pack_offset, &avail);
2007         used = unpack_object_header_buffer(buf, avail, &type, &size);
2008         if (used == 0)
2009                 die(_("unable to parse object header of %s"),
2010                     oid_to_hex(&e->idx.oid));
2011
2012         unuse_pack(&w_curs);
2013         packing_data_unlock(&to_pack);
2014         return size;
2015 }
2016
2017 static int try_delta(struct unpacked *trg, struct unpacked *src,
2018                      unsigned max_depth, unsigned long *mem_usage)
2019 {
2020         struct object_entry *trg_entry = trg->entry;
2021         struct object_entry *src_entry = src->entry;
2022         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
2023         unsigned ref_depth;
2024         enum object_type type;
2025         void *delta_buf;
2026
2027         /* Don't bother doing diffs between different types */
2028         if (oe_type(trg_entry) != oe_type(src_entry))
2029                 return -1;
2030
2031         /*
2032          * We do not bother to try a delta that we discarded on an
2033          * earlier try, but only when reusing delta data.  Note that
2034          * src_entry that is marked as the preferred_base should always
2035          * be considered, as even if we produce a suboptimal delta against
2036          * it, we will still save the transfer cost, as we already know
2037          * the other side has it and we won't send src_entry at all.
2038          */
2039         if (reuse_delta && IN_PACK(trg_entry) &&
2040             IN_PACK(trg_entry) == IN_PACK(src_entry) &&
2041             !src_entry->preferred_base &&
2042             trg_entry->in_pack_type != OBJ_REF_DELTA &&
2043             trg_entry->in_pack_type != OBJ_OFS_DELTA)
2044                 return 0;
2045
2046         /* Let's not bust the allowed depth. */
2047         if (src->depth >= max_depth)
2048                 return 0;
2049
2050         /* Now some size filtering heuristics. */
2051         trg_size = SIZE(trg_entry);
2052         if (!DELTA(trg_entry)) {
2053                 max_size = trg_size/2 - the_hash_algo->rawsz;
2054                 ref_depth = 1;
2055         } else {
2056                 max_size = DELTA_SIZE(trg_entry);
2057                 ref_depth = trg->depth;
2058         }
2059         max_size = (uint64_t)max_size * (max_depth - src->depth) /
2060                                                 (max_depth - ref_depth + 1);
2061         if (max_size == 0)
2062                 return 0;
2063         src_size = SIZE(src_entry);
2064         sizediff = src_size < trg_size ? trg_size - src_size : 0;
2065         if (sizediff >= max_size)
2066                 return 0;
2067         if (trg_size < src_size / 32)
2068                 return 0;
2069
2070         if (!in_same_island(&trg->entry->idx.oid, &src->entry->idx.oid))
2071                 return 0;
2072
2073         /* Load data if not already done */
2074         if (!trg->data) {
2075                 packing_data_lock(&to_pack);
2076                 trg->data = read_object_file(&trg_entry->idx.oid, &type, &sz);
2077                 packing_data_unlock(&to_pack);
2078                 if (!trg->data)
2079                         die(_("object %s cannot be read"),
2080                             oid_to_hex(&trg_entry->idx.oid));
2081                 if (sz != trg_size)
2082                         die(_("object %s inconsistent object length (%"PRIuMAX" vs %"PRIuMAX")"),
2083                             oid_to_hex(&trg_entry->idx.oid), (uintmax_t)sz,
2084                             (uintmax_t)trg_size);
2085                 *mem_usage += sz;
2086         }
2087         if (!src->data) {
2088                 packing_data_lock(&to_pack);
2089                 src->data = read_object_file(&src_entry->idx.oid, &type, &sz);
2090                 packing_data_unlock(&to_pack);
2091                 if (!src->data) {
2092                         if (src_entry->preferred_base) {
2093                                 static int warned = 0;
2094                                 if (!warned++)
2095                                         warning(_("object %s cannot be read"),
2096                                                 oid_to_hex(&src_entry->idx.oid));
2097                                 /*
2098                                  * Those objects are not included in the
2099                                  * resulting pack.  Be resilient and ignore
2100                                  * them if they can't be read, in case the
2101                                  * pack could be created nevertheless.
2102                                  */
2103                                 return 0;
2104                         }
2105                         die(_("object %s cannot be read"),
2106                             oid_to_hex(&src_entry->idx.oid));
2107                 }
2108                 if (sz != src_size)
2109                         die(_("object %s inconsistent object length (%"PRIuMAX" vs %"PRIuMAX")"),
2110                             oid_to_hex(&src_entry->idx.oid), (uintmax_t)sz,
2111                             (uintmax_t)src_size);
2112                 *mem_usage += sz;
2113         }
2114         if (!src->index) {
2115                 src->index = create_delta_index(src->data, src_size);
2116                 if (!src->index) {
2117                         static int warned = 0;
2118                         if (!warned++)
2119                                 warning(_("suboptimal pack - out of memory"));
2120                         return 0;
2121                 }
2122                 *mem_usage += sizeof_delta_index(src->index);
2123         }
2124
2125         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
2126         if (!delta_buf)
2127                 return 0;
2128
2129         if (DELTA(trg_entry)) {
2130                 /* Prefer only shallower same-sized deltas. */
2131                 if (delta_size == DELTA_SIZE(trg_entry) &&
2132                     src->depth + 1 >= trg->depth) {
2133                         free(delta_buf);
2134                         return 0;
2135                 }
2136         }
2137
2138         /*
2139          * Handle memory allocation outside of the cache
2140          * accounting lock.  Compiler will optimize the strangeness
2141          * away when NO_PTHREADS is defined.
2142          */
2143         free(trg_entry->delta_data);
2144         cache_lock();
2145         if (trg_entry->delta_data) {
2146                 delta_cache_size -= DELTA_SIZE(trg_entry);
2147                 trg_entry->delta_data = NULL;
2148         }
2149         if (delta_cacheable(src_size, trg_size, delta_size)) {
2150                 delta_cache_size += delta_size;
2151                 cache_unlock();
2152                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
2153         } else {
2154                 cache_unlock();
2155                 free(delta_buf);
2156         }
2157
2158         SET_DELTA(trg_entry, src_entry);
2159         SET_DELTA_SIZE(trg_entry, delta_size);
2160         trg->depth = src->depth + 1;
2161
2162         return 1;
2163 }
2164
2165 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
2166 {
2167         struct object_entry *child = DELTA_CHILD(me);
2168         unsigned int m = n;
2169         while (child) {
2170                 const unsigned int c = check_delta_limit(child, n + 1);
2171                 if (m < c)
2172                         m = c;
2173                 child = DELTA_SIBLING(child);
2174         }
2175         return m;
2176 }
2177
2178 static unsigned long free_unpacked(struct unpacked *n)
2179 {
2180         unsigned long freed_mem = sizeof_delta_index(n->index);
2181         free_delta_index(n->index);
2182         n->index = NULL;
2183         if (n->data) {
2184                 freed_mem += SIZE(n->entry);
2185                 FREE_AND_NULL(n->data);
2186         }
2187         n->entry = NULL;
2188         n->depth = 0;
2189         return freed_mem;
2190 }
2191
2192 static void find_deltas(struct object_entry **list, unsigned *list_size,
2193                         int window, int depth, unsigned *processed)
2194 {
2195         uint32_t i, idx = 0, count = 0;
2196         struct unpacked *array;
2197         unsigned long mem_usage = 0;
2198
2199         array = xcalloc(window, sizeof(struct unpacked));
2200
2201         for (;;) {
2202                 struct object_entry *entry;
2203                 struct unpacked *n = array + idx;
2204                 int j, max_depth, best_base = -1;
2205
2206                 progress_lock();
2207                 if (!*list_size) {
2208                         progress_unlock();
2209                         break;
2210                 }
2211                 entry = *list++;
2212                 (*list_size)--;
2213                 if (!entry->preferred_base) {
2214                         (*processed)++;
2215                         display_progress(progress_state, *processed);
2216                 }
2217                 progress_unlock();
2218
2219                 mem_usage -= free_unpacked(n);
2220                 n->entry = entry;
2221
2222                 while (window_memory_limit &&
2223                        mem_usage > window_memory_limit &&
2224                        count > 1) {
2225                         const uint32_t tail = (idx + window - count) % window;
2226                         mem_usage -= free_unpacked(array + tail);
2227                         count--;
2228                 }
2229
2230                 /* We do not compute delta to *create* objects we are not
2231                  * going to pack.
2232                  */
2233                 if (entry->preferred_base)
2234                         goto next;
2235
2236                 /*
2237                  * If the current object is at pack edge, take the depth the
2238                  * objects that depend on the current object into account
2239                  * otherwise they would become too deep.
2240                  */
2241                 max_depth = depth;
2242                 if (DELTA_CHILD(entry)) {
2243                         max_depth -= check_delta_limit(entry, 0);
2244                         if (max_depth <= 0)
2245                                 goto next;
2246                 }
2247
2248                 j = window;
2249                 while (--j > 0) {
2250                         int ret;
2251                         uint32_t other_idx = idx + j;
2252                         struct unpacked *m;
2253                         if (other_idx >= window)
2254                                 other_idx -= window;
2255                         m = array + other_idx;
2256                         if (!m->entry)
2257                                 break;
2258                         ret = try_delta(n, m, max_depth, &mem_usage);
2259                         if (ret < 0)
2260                                 break;
2261                         else if (ret > 0)
2262                                 best_base = other_idx;
2263                 }
2264
2265                 /*
2266                  * If we decided to cache the delta data, then it is best
2267                  * to compress it right away.  First because we have to do
2268                  * it anyway, and doing it here while we're threaded will
2269                  * save a lot of time in the non threaded write phase,
2270                  * as well as allow for caching more deltas within
2271                  * the same cache size limit.
2272                  * ...
2273                  * But only if not writing to stdout, since in that case
2274                  * the network is most likely throttling writes anyway,
2275                  * and therefore it is best to go to the write phase ASAP
2276                  * instead, as we can afford spending more time compressing
2277                  * between writes at that moment.
2278                  */
2279                 if (entry->delta_data && !pack_to_stdout) {
2280                         unsigned long size;
2281
2282                         size = do_compress(&entry->delta_data, DELTA_SIZE(entry));
2283                         if (size < (1U << OE_Z_DELTA_BITS)) {
2284                                 entry->z_delta_size = size;
2285                                 cache_lock();
2286                                 delta_cache_size -= DELTA_SIZE(entry);
2287                                 delta_cache_size += entry->z_delta_size;
2288                                 cache_unlock();
2289                         } else {
2290                                 FREE_AND_NULL(entry->delta_data);
2291                                 entry->z_delta_size = 0;
2292                         }
2293                 }
2294
2295                 /* if we made n a delta, and if n is already at max
2296                  * depth, leaving it in the window is pointless.  we
2297                  * should evict it first.
2298                  */
2299                 if (DELTA(entry) && max_depth <= n->depth)
2300                         continue;
2301
2302                 /*
2303                  * Move the best delta base up in the window, after the
2304                  * currently deltified object, to keep it longer.  It will
2305                  * be the first base object to be attempted next.
2306                  */
2307                 if (DELTA(entry)) {
2308                         struct unpacked swap = array[best_base];
2309                         int dist = (window + idx - best_base) % window;
2310                         int dst = best_base;
2311                         while (dist--) {
2312                                 int src = (dst + 1) % window;
2313                                 array[dst] = array[src];
2314                                 dst = src;
2315                         }
2316                         array[dst] = swap;
2317                 }
2318
2319                 next:
2320                 idx++;
2321                 if (count + 1 < window)
2322                         count++;
2323                 if (idx >= window)
2324                         idx = 0;
2325         }
2326
2327         for (i = 0; i < window; ++i) {
2328                 free_delta_index(array[i].index);
2329                 free(array[i].data);
2330         }
2331         free(array);
2332 }
2333
2334 static void try_to_free_from_threads(size_t size)
2335 {
2336         packing_data_lock(&to_pack);
2337         release_pack_memory(size);
2338         packing_data_unlock(&to_pack);
2339 }
2340
2341 static try_to_free_t old_try_to_free_routine;
2342
2343 /*
2344  * The main object list is split into smaller lists, each is handed to
2345  * one worker.
2346  *
2347  * The main thread waits on the condition that (at least) one of the workers
2348  * has stopped working (which is indicated in the .working member of
2349  * struct thread_params).
2350  *
2351  * When a work thread has completed its work, it sets .working to 0 and
2352  * signals the main thread and waits on the condition that .data_ready
2353  * becomes 1.
2354  *
2355  * The main thread steals half of the work from the worker that has
2356  * most work left to hand it to the idle worker.
2357  */
2358
2359 struct thread_params {
2360         pthread_t thread;
2361         struct object_entry **list;
2362         unsigned list_size;
2363         unsigned remaining;
2364         int window;
2365         int depth;
2366         int working;
2367         int data_ready;
2368         pthread_mutex_t mutex;
2369         pthread_cond_t cond;
2370         unsigned *processed;
2371 };
2372
2373 static pthread_cond_t progress_cond;
2374
2375 /*
2376  * Mutex and conditional variable can't be statically-initialized on Windows.
2377  */
2378 static void init_threaded_search(void)
2379 {
2380         pthread_mutex_init(&cache_mutex, NULL);
2381         pthread_mutex_init(&progress_mutex, NULL);
2382         pthread_cond_init(&progress_cond, NULL);
2383         old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
2384 }
2385
2386 static void cleanup_threaded_search(void)
2387 {
2388         set_try_to_free_routine(old_try_to_free_routine);
2389         pthread_cond_destroy(&progress_cond);
2390         pthread_mutex_destroy(&cache_mutex);
2391         pthread_mutex_destroy(&progress_mutex);
2392 }
2393
2394 static void *threaded_find_deltas(void *arg)
2395 {
2396         struct thread_params *me = arg;
2397
2398         progress_lock();
2399         while (me->remaining) {
2400                 progress_unlock();
2401
2402                 find_deltas(me->list, &me->remaining,
2403                             me->window, me->depth, me->processed);
2404
2405                 progress_lock();
2406                 me->working = 0;
2407                 pthread_cond_signal(&progress_cond);
2408                 progress_unlock();
2409
2410                 /*
2411                  * We must not set ->data_ready before we wait on the
2412                  * condition because the main thread may have set it to 1
2413                  * before we get here. In order to be sure that new
2414                  * work is available if we see 1 in ->data_ready, it
2415                  * was initialized to 0 before this thread was spawned
2416                  * and we reset it to 0 right away.
2417                  */
2418                 pthread_mutex_lock(&me->mutex);
2419                 while (!me->data_ready)
2420                         pthread_cond_wait(&me->cond, &me->mutex);
2421                 me->data_ready = 0;
2422                 pthread_mutex_unlock(&me->mutex);
2423
2424                 progress_lock();
2425         }
2426         progress_unlock();
2427         /* leave ->working 1 so that this doesn't get more work assigned */
2428         return NULL;
2429 }
2430
2431 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
2432                            int window, int depth, unsigned *processed)
2433 {
2434         struct thread_params *p;
2435         int i, ret, active_threads = 0;
2436
2437         init_threaded_search();
2438
2439         if (delta_search_threads <= 1) {
2440                 find_deltas(list, &list_size, window, depth, processed);
2441                 cleanup_threaded_search();
2442                 return;
2443         }
2444         if (progress > pack_to_stdout)
2445                 fprintf_ln(stderr, _("Delta compression using up to %d threads"),
2446                            delta_search_threads);
2447         p = xcalloc(delta_search_threads, sizeof(*p));
2448
2449         /* Partition the work amongst work threads. */
2450         for (i = 0; i < delta_search_threads; i++) {
2451                 unsigned sub_size = list_size / (delta_search_threads - i);
2452
2453                 /* don't use too small segments or no deltas will be found */
2454                 if (sub_size < 2*window && i+1 < delta_search_threads)
2455                         sub_size = 0;
2456
2457                 p[i].window = window;
2458                 p[i].depth = depth;
2459                 p[i].processed = processed;
2460                 p[i].working = 1;
2461                 p[i].data_ready = 0;
2462
2463                 /* try to split chunks on "path" boundaries */
2464                 while (sub_size && sub_size < list_size &&
2465                        list[sub_size]->hash &&
2466                        list[sub_size]->hash == list[sub_size-1]->hash)
2467                         sub_size++;
2468
2469                 p[i].list = list;
2470                 p[i].list_size = sub_size;
2471                 p[i].remaining = sub_size;
2472
2473                 list += sub_size;
2474                 list_size -= sub_size;
2475         }
2476
2477         /* Start work threads. */
2478         for (i = 0; i < delta_search_threads; i++) {
2479                 if (!p[i].list_size)
2480                         continue;
2481                 pthread_mutex_init(&p[i].mutex, NULL);
2482                 pthread_cond_init(&p[i].cond, NULL);
2483                 ret = pthread_create(&p[i].thread, NULL,
2484                                      threaded_find_deltas, &p[i]);
2485                 if (ret)
2486                         die(_("unable to create thread: %s"), strerror(ret));
2487                 active_threads++;
2488         }
2489
2490         /*
2491          * Now let's wait for work completion.  Each time a thread is done
2492          * with its work, we steal half of the remaining work from the
2493          * thread with the largest number of unprocessed objects and give
2494          * it to that newly idle thread.  This ensure good load balancing
2495          * until the remaining object list segments are simply too short
2496          * to be worth splitting anymore.
2497          */
2498         while (active_threads) {
2499                 struct thread_params *target = NULL;
2500                 struct thread_params *victim = NULL;
2501                 unsigned sub_size = 0;
2502
2503                 progress_lock();
2504                 for (;;) {
2505                         for (i = 0; !target && i < delta_search_threads; i++)
2506                                 if (!p[i].working)
2507                                         target = &p[i];
2508                         if (target)
2509                                 break;
2510                         pthread_cond_wait(&progress_cond, &progress_mutex);
2511                 }
2512
2513                 for (i = 0; i < delta_search_threads; i++)
2514                         if (p[i].remaining > 2*window &&
2515                             (!victim || victim->remaining < p[i].remaining))
2516                                 victim = &p[i];
2517                 if (victim) {
2518                         sub_size = victim->remaining / 2;
2519                         list = victim->list + victim->list_size - sub_size;
2520                         while (sub_size && list[0]->hash &&
2521                                list[0]->hash == list[-1]->hash) {
2522                                 list++;
2523                                 sub_size--;
2524                         }
2525                         if (!sub_size) {
2526                                 /*
2527                                  * It is possible for some "paths" to have
2528                                  * so many objects that no hash boundary
2529                                  * might be found.  Let's just steal the
2530                                  * exact half in that case.
2531                                  */
2532                                 sub_size = victim->remaining / 2;
2533                                 list -= sub_size;
2534                         }
2535                         target->list = list;
2536                         victim->list_size -= sub_size;
2537                         victim->remaining -= sub_size;
2538                 }
2539                 target->list_size = sub_size;
2540                 target->remaining = sub_size;
2541                 target->working = 1;
2542                 progress_unlock();
2543
2544                 pthread_mutex_lock(&target->mutex);
2545                 target->data_ready = 1;
2546                 pthread_cond_signal(&target->cond);
2547                 pthread_mutex_unlock(&target->mutex);
2548
2549                 if (!sub_size) {
2550                         pthread_join(target->thread, NULL);
2551                         pthread_cond_destroy(&target->cond);
2552                         pthread_mutex_destroy(&target->mutex);
2553                         active_threads--;
2554                 }
2555         }
2556         cleanup_threaded_search();
2557         free(p);
2558 }
2559
2560 static void add_tag_chain(const struct object_id *oid)
2561 {
2562         struct tag *tag;
2563
2564         /*
2565          * We catch duplicates already in add_object_entry(), but we'd
2566          * prefer to do this extra check to avoid having to parse the
2567          * tag at all if we already know that it's being packed (e.g., if
2568          * it was included via bitmaps, we would not have parsed it
2569          * previously).
2570          */
2571         if (packlist_find(&to_pack, oid->hash, NULL))
2572                 return;
2573
2574         tag = lookup_tag(the_repository, oid);
2575         while (1) {
2576                 if (!tag || parse_tag(tag) || !tag->tagged)
2577                         die(_("unable to pack objects reachable from tag %s"),
2578                             oid_to_hex(oid));
2579
2580                 add_object_entry(&tag->object.oid, OBJ_TAG, NULL, 0);
2581
2582                 if (tag->tagged->type != OBJ_TAG)
2583                         return;
2584
2585                 tag = (struct tag *)tag->tagged;
2586         }
2587 }
2588
2589 static int add_ref_tag(const char *path, const struct object_id *oid, int flag, void *cb_data)
2590 {
2591         struct object_id peeled;
2592
2593         if (starts_with(path, "refs/tags/") && /* is a tag? */
2594             !peel_ref(path, &peeled)    && /* peelable? */
2595             packlist_find(&to_pack, peeled.hash, NULL))      /* object packed? */
2596                 add_tag_chain(oid);
2597         return 0;
2598 }
2599
2600 static void prepare_pack(int window, int depth)
2601 {
2602         struct object_entry **delta_list;
2603         uint32_t i, nr_deltas;
2604         unsigned n;
2605
2606         if (use_delta_islands)
2607                 resolve_tree_islands(the_repository, progress, &to_pack);
2608
2609         get_object_details();
2610
2611         /*
2612          * If we're locally repacking then we need to be doubly careful
2613          * from now on in order to make sure no stealth corruption gets
2614          * propagated to the new pack.  Clients receiving streamed packs
2615          * should validate everything they get anyway so no need to incur
2616          * the additional cost here in that case.
2617          */
2618         if (!pack_to_stdout)
2619                 do_check_packed_object_crc = 1;
2620
2621         if (!to_pack.nr_objects || !window || !depth)
2622                 return;
2623
2624         ALLOC_ARRAY(delta_list, to_pack.nr_objects);
2625         nr_deltas = n = 0;
2626
2627         for (i = 0; i < to_pack.nr_objects; i++) {
2628                 struct object_entry *entry = to_pack.objects + i;
2629
2630                 if (DELTA(entry))
2631                         /* This happens if we decided to reuse existing
2632                          * delta from a pack.  "reuse_delta &&" is implied.
2633                          */
2634                         continue;
2635
2636                 if (!entry->type_valid ||
2637                     oe_size_less_than(&to_pack, entry, 50))
2638                         continue;
2639
2640                 if (entry->no_try_delta)
2641                         continue;
2642
2643                 if (!entry->preferred_base) {
2644                         nr_deltas++;
2645                         if (oe_type(entry) < 0)
2646                                 die(_("unable to get type of object %s"),
2647                                     oid_to_hex(&entry->idx.oid));
2648                 } else {
2649                         if (oe_type(entry) < 0) {
2650                                 /*
2651                                  * This object is not found, but we
2652                                  * don't have to include it anyway.
2653                                  */
2654                                 continue;
2655                         }
2656                 }
2657
2658                 delta_list[n++] = entry;
2659         }
2660
2661         if (nr_deltas && n > 1) {
2662                 unsigned nr_done = 0;
2663                 if (progress)
2664                         progress_state = start_progress(_("Compressing objects"),
2665                                                         nr_deltas);
2666                 QSORT(delta_list, n, type_size_sort);
2667                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2668                 stop_progress(&progress_state);
2669                 if (nr_done != nr_deltas)
2670                         die(_("inconsistency with delta count"));
2671         }
2672         free(delta_list);
2673 }
2674
2675 static int git_pack_config(const char *k, const char *v, void *cb)
2676 {
2677         if (!strcmp(k, "pack.window")) {
2678                 window = git_config_int(k, v);
2679                 return 0;
2680         }
2681         if (!strcmp(k, "pack.windowmemory")) {
2682                 window_memory_limit = git_config_ulong(k, v);
2683                 return 0;
2684         }
2685         if (!strcmp(k, "pack.depth")) {
2686                 depth = git_config_int(k, v);
2687                 return 0;
2688         }
2689         if (!strcmp(k, "pack.deltacachesize")) {
2690                 max_delta_cache_size = git_config_int(k, v);
2691                 return 0;
2692         }
2693         if (!strcmp(k, "pack.deltacachelimit")) {
2694                 cache_max_small_delta_size = git_config_int(k, v);
2695                 return 0;
2696         }
2697         if (!strcmp(k, "pack.writebitmaphashcache")) {
2698                 if (git_config_bool(k, v))
2699                         write_bitmap_options |= BITMAP_OPT_HASH_CACHE;
2700                 else
2701                         write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
2702         }
2703         if (!strcmp(k, "pack.usebitmaps")) {
2704                 use_bitmap_index_default = git_config_bool(k, v);
2705                 return 0;
2706         }
2707         if (!strcmp(k, "pack.usesparse")) {
2708                 sparse = git_config_bool(k, v);
2709                 return 0;
2710         }
2711         if (!strcmp(k, "pack.threads")) {
2712                 delta_search_threads = git_config_int(k, v);
2713                 if (delta_search_threads < 0)
2714                         die(_("invalid number of threads specified (%d)"),
2715                             delta_search_threads);
2716                 if (!HAVE_THREADS && delta_search_threads != 1) {
2717                         warning(_("no threads support, ignoring %s"), k);
2718                         delta_search_threads = 0;
2719                 }
2720                 return 0;
2721         }
2722         if (!strcmp(k, "pack.indexversion")) {
2723                 pack_idx_opts.version = git_config_int(k, v);
2724                 if (pack_idx_opts.version > 2)
2725                         die(_("bad pack.indexversion=%"PRIu32),
2726                             pack_idx_opts.version);
2727                 return 0;
2728         }
2729         return git_default_config(k, v, cb);
2730 }
2731
2732 static void read_object_list_from_stdin(void)
2733 {
2734         char line[GIT_MAX_HEXSZ + 1 + PATH_MAX + 2];
2735         struct object_id oid;
2736         const char *p;
2737
2738         for (;;) {
2739                 if (!fgets(line, sizeof(line), stdin)) {
2740                         if (feof(stdin))
2741                                 break;
2742                         if (!ferror(stdin))
2743                                 die("BUG: fgets returned NULL, not EOF, not error!");
2744                         if (errno != EINTR)
2745                                 die_errno("fgets");
2746                         clearerr(stdin);
2747                         continue;
2748                 }
2749                 if (line[0] == '-') {
2750                         if (get_oid_hex(line+1, &oid))
2751                                 die(_("expected edge object ID, got garbage:\n %s"),
2752                                     line);
2753                         add_preferred_base(&oid);
2754                         continue;
2755                 }
2756                 if (parse_oid_hex(line, &oid, &p))
2757                         die(_("expected object ID, got garbage:\n %s"), line);
2758
2759                 add_preferred_base_object(p + 1);
2760                 add_object_entry(&oid, OBJ_NONE, p + 1, 0);
2761         }
2762 }
2763
2764 /* Remember to update object flag allocation in object.h */
2765 #define OBJECT_ADDED (1u<<20)
2766
2767 static void show_commit(struct commit *commit, void *data)
2768 {
2769         add_object_entry(&commit->object.oid, OBJ_COMMIT, NULL, 0);
2770         commit->object.flags |= OBJECT_ADDED;
2771
2772         if (write_bitmap_index)
2773                 index_commit_for_bitmap(commit);
2774
2775         if (use_delta_islands)
2776                 propagate_island_marks(commit);
2777 }
2778
2779 static void show_object(struct object *obj, const char *name, void *data)
2780 {
2781         add_preferred_base_object(name);
2782         add_object_entry(&obj->oid, obj->type, name, 0);
2783         obj->flags |= OBJECT_ADDED;
2784
2785         if (use_delta_islands) {
2786                 const char *p;
2787                 unsigned depth;
2788                 struct object_entry *ent;
2789
2790                 /* the empty string is a root tree, which is depth 0 */
2791                 depth = *name ? 1 : 0;
2792                 for (p = strchr(name, '/'); p; p = strchr(p + 1, '/'))
2793                         depth++;
2794
2795                 ent = packlist_find(&to_pack, obj->oid.hash, NULL);
2796                 if (ent && depth > oe_tree_depth(&to_pack, ent))
2797                         oe_set_tree_depth(&to_pack, ent, depth);
2798         }
2799 }
2800
2801 static void show_object__ma_allow_any(struct object *obj, const char *name, void *data)
2802 {
2803         assert(arg_missing_action == MA_ALLOW_ANY);
2804
2805         /*
2806          * Quietly ignore ALL missing objects.  This avoids problems with
2807          * staging them now and getting an odd error later.
2808          */
2809         if (!has_object_file(&obj->oid))
2810                 return;
2811
2812         show_object(obj, name, data);
2813 }
2814
2815 static void show_object__ma_allow_promisor(struct object *obj, const char *name, void *data)
2816 {
2817         assert(arg_missing_action == MA_ALLOW_PROMISOR);
2818
2819         /*
2820          * Quietly ignore EXPECTED missing objects.  This avoids problems with
2821          * staging them now and getting an odd error later.
2822          */
2823         if (!has_object_file(&obj->oid) && is_promisor_object(&obj->oid))
2824                 return;
2825
2826         show_object(obj, name, data);
2827 }
2828
2829 static int option_parse_missing_action(const struct option *opt,
2830                                        const char *arg, int unset)
2831 {
2832         assert(arg);
2833         assert(!unset);
2834
2835         if (!strcmp(arg, "error")) {
2836                 arg_missing_action = MA_ERROR;
2837                 fn_show_object = show_object;
2838                 return 0;
2839         }
2840
2841         if (!strcmp(arg, "allow-any")) {
2842                 arg_missing_action = MA_ALLOW_ANY;
2843                 fetch_if_missing = 0;
2844                 fn_show_object = show_object__ma_allow_any;
2845                 return 0;
2846         }
2847
2848         if (!strcmp(arg, "allow-promisor")) {
2849                 arg_missing_action = MA_ALLOW_PROMISOR;
2850                 fetch_if_missing = 0;
2851                 fn_show_object = show_object__ma_allow_promisor;
2852                 return 0;
2853         }
2854
2855         die(_("invalid value for --missing"));
2856         return 0;
2857 }
2858
2859 static void show_edge(struct commit *commit)
2860 {
2861         add_preferred_base(&commit->object.oid);
2862 }
2863
2864 struct in_pack_object {
2865         off_t offset;
2866         struct object *object;
2867 };
2868
2869 struct in_pack {
2870         unsigned int alloc;
2871         unsigned int nr;
2872         struct in_pack_object *array;
2873 };
2874
2875 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2876 {
2877         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->oid.hash, p);
2878         in_pack->array[in_pack->nr].object = object;
2879         in_pack->nr++;
2880 }
2881
2882 /*
2883  * Compare the objects in the offset order, in order to emulate the
2884  * "git rev-list --objects" output that produced the pack originally.
2885  */
2886 static int ofscmp(const void *a_, const void *b_)
2887 {
2888         struct in_pack_object *a = (struct in_pack_object *)a_;
2889         struct in_pack_object *b = (struct in_pack_object *)b_;
2890
2891         if (a->offset < b->offset)
2892                 return -1;
2893         else if (a->offset > b->offset)
2894                 return 1;
2895         else
2896                 return oidcmp(&a->object->oid, &b->object->oid);
2897 }
2898
2899 static void add_objects_in_unpacked_packs(struct rev_info *revs)
2900 {
2901         struct packed_git *p;
2902         struct in_pack in_pack;
2903         uint32_t i;
2904
2905         memset(&in_pack, 0, sizeof(in_pack));
2906
2907         for (p = get_all_packs(the_repository); p; p = p->next) {
2908                 struct object_id oid;
2909                 struct object *o;
2910
2911                 if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
2912                         continue;
2913                 if (open_pack_index(p))
2914                         die(_("cannot open pack index"));
2915
2916                 ALLOC_GROW(in_pack.array,
2917                            in_pack.nr + p->num_objects,
2918                            in_pack.alloc);
2919
2920                 for (i = 0; i < p->num_objects; i++) {
2921                         nth_packed_object_oid(&oid, p, i);
2922                         o = lookup_unknown_object(oid.hash);
2923                         if (!(o->flags & OBJECT_ADDED))
2924                                 mark_in_pack_object(o, p, &in_pack);
2925                         o->flags |= OBJECT_ADDED;
2926                 }
2927         }
2928
2929         if (in_pack.nr) {
2930                 QSORT(in_pack.array, in_pack.nr, ofscmp);
2931                 for (i = 0; i < in_pack.nr; i++) {
2932                         struct object *o = in_pack.array[i].object;
2933                         add_object_entry(&o->oid, o->type, "", 0);
2934                 }
2935         }
2936         free(in_pack.array);
2937 }
2938
2939 static int add_loose_object(const struct object_id *oid, const char *path,
2940                             void *data)
2941 {
2942         enum object_type type = oid_object_info(the_repository, oid, NULL);
2943
2944         if (type < 0) {
2945                 warning(_("loose object at %s could not be examined"), path);
2946                 return 0;
2947         }
2948
2949         add_object_entry(oid, type, "", 0);
2950         return 0;
2951 }
2952
2953 /*
2954  * We actually don't even have to worry about reachability here.
2955  * add_object_entry will weed out duplicates, so we just add every
2956  * loose object we find.
2957  */
2958 static void add_unreachable_loose_objects(void)
2959 {
2960         for_each_loose_file_in_objdir(get_object_directory(),
2961                                       add_loose_object,
2962                                       NULL, NULL, NULL);
2963 }
2964
2965 static int has_sha1_pack_kept_or_nonlocal(const struct object_id *oid)
2966 {
2967         static struct packed_git *last_found = (void *)1;
2968         struct packed_git *p;
2969
2970         p = (last_found != (void *)1) ? last_found :
2971                                         get_all_packs(the_repository);
2972
2973         while (p) {
2974                 if ((!p->pack_local || p->pack_keep ||
2975                                 p->pack_keep_in_core) &&
2976                         find_pack_entry_one(oid->hash, p)) {
2977                         last_found = p;
2978                         return 1;
2979                 }
2980                 if (p == last_found)
2981                         p = get_all_packs(the_repository);
2982                 else
2983                         p = p->next;
2984                 if (p == last_found)
2985                         p = p->next;
2986         }
2987         return 0;
2988 }
2989
2990 /*
2991  * Store a list of sha1s that are should not be discarded
2992  * because they are either written too recently, or are
2993  * reachable from another object that was.
2994  *
2995  * This is filled by get_object_list.
2996  */
2997 static struct oid_array recent_objects;
2998
2999 static int loosened_object_can_be_discarded(const struct object_id *oid,
3000                                             timestamp_t mtime)
3001 {
3002         if (!unpack_unreachable_expiration)
3003                 return 0;
3004         if (mtime > unpack_unreachable_expiration)
3005                 return 0;
3006         if (oid_array_lookup(&recent_objects, oid) >= 0)
3007                 return 0;
3008         return 1;
3009 }
3010
3011 static void loosen_unused_packed_objects(struct rev_info *revs)
3012 {
3013         struct packed_git *p;
3014         uint32_t i;
3015         struct object_id oid;
3016
3017         for (p = get_all_packs(the_repository); p; p = p->next) {
3018                 if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
3019                         continue;
3020
3021                 if (open_pack_index(p))
3022                         die(_("cannot open pack index"));
3023
3024                 for (i = 0; i < p->num_objects; i++) {
3025                         nth_packed_object_oid(&oid, p, i);
3026                         if (!packlist_find(&to_pack, oid.hash, NULL) &&
3027                             !has_sha1_pack_kept_or_nonlocal(&oid) &&
3028                             !loosened_object_can_be_discarded(&oid, p->mtime))
3029                                 if (force_object_loose(&oid, p->mtime))
3030                                         die(_("unable to force loose object"));
3031                 }
3032         }
3033 }
3034
3035 /*
3036  * This tracks any options which pack-reuse code expects to be on, or which a
3037  * reader of the pack might not understand, and which would therefore prevent
3038  * blind reuse of what we have on disk.
3039  */
3040 static int pack_options_allow_reuse(void)
3041 {
3042         return pack_to_stdout &&
3043                allow_ofs_delta &&
3044                !ignore_packed_keep_on_disk &&
3045                !ignore_packed_keep_in_core &&
3046                (!local || !have_non_local_packs) &&
3047                !incremental;
3048 }
3049
3050 static int get_object_list_from_bitmap(struct rev_info *revs)
3051 {
3052         if (!(bitmap_git = prepare_bitmap_walk(revs)))
3053                 return -1;
3054
3055         if (pack_options_allow_reuse() &&
3056             !reuse_partial_packfile_from_bitmap(
3057                         bitmap_git,
3058                         &reuse_packfile,
3059                         &reuse_packfile_objects,
3060                         &reuse_packfile_offset)) {
3061                 assert(reuse_packfile_objects);
3062                 nr_result += reuse_packfile_objects;
3063                 display_progress(progress_state, nr_result);
3064         }
3065
3066         traverse_bitmap_commit_list(bitmap_git, &add_object_entry_from_bitmap);
3067         return 0;
3068 }
3069
3070 static void record_recent_object(struct object *obj,
3071                                  const char *name,
3072                                  void *data)
3073 {
3074         oid_array_append(&recent_objects, &obj->oid);
3075 }
3076
3077 static void record_recent_commit(struct commit *commit, void *data)
3078 {
3079         oid_array_append(&recent_objects, &commit->object.oid);
3080 }
3081
3082 static void get_object_list(int ac, const char **av)
3083 {
3084         struct rev_info revs;
3085         struct setup_revision_opt s_r_opt = {
3086                 .allow_exclude_promisor_objects = 1,
3087         };
3088         char line[1000];
3089         int flags = 0;
3090         int save_warning;
3091
3092         repo_init_revisions(the_repository, &revs, NULL);
3093         save_commit_buffer = 0;
3094         setup_revisions(ac, av, &revs, &s_r_opt);
3095
3096         /* make sure shallows are read */
3097         is_repository_shallow(the_repository);
3098
3099         save_warning = warn_on_object_refname_ambiguity;
3100         warn_on_object_refname_ambiguity = 0;
3101
3102         while (fgets(line, sizeof(line), stdin) != NULL) {
3103                 int len = strlen(line);
3104                 if (len && line[len - 1] == '\n')
3105                         line[--len] = 0;
3106                 if (!len)
3107                         break;
3108                 if (*line == '-') {
3109                         if (!strcmp(line, "--not")) {
3110                                 flags ^= UNINTERESTING;
3111                                 write_bitmap_index = 0;
3112                                 continue;
3113                         }
3114                         if (starts_with(line, "--shallow ")) {
3115                                 struct object_id oid;
3116                                 if (get_oid_hex(line + 10, &oid))
3117                                         die("not an SHA-1 '%s'", line + 10);
3118                                 register_shallow(the_repository, &oid);
3119                                 use_bitmap_index = 0;
3120                                 continue;
3121                         }
3122                         die(_("not a rev '%s'"), line);
3123                 }
3124                 if (handle_revision_arg(line, &revs, flags, REVARG_CANNOT_BE_FILENAME))
3125                         die(_("bad revision '%s'"), line);
3126         }
3127
3128         warn_on_object_refname_ambiguity = save_warning;
3129
3130         if (use_bitmap_index && !get_object_list_from_bitmap(&revs))
3131                 return;
3132
3133         if (use_delta_islands)
3134                 load_delta_islands(the_repository);
3135
3136         if (prepare_revision_walk(&revs))
3137                 die(_("revision walk setup failed"));
3138         mark_edges_uninteresting(&revs, show_edge, sparse);
3139
3140         if (!fn_show_object)
3141                 fn_show_object = show_object;
3142         traverse_commit_list_filtered(&filter_options, &revs,
3143                                       show_commit, fn_show_object, NULL,
3144                                       NULL);
3145
3146         if (unpack_unreachable_expiration) {
3147                 revs.ignore_missing_links = 1;
3148                 if (add_unseen_recent_objects_to_traversal(&revs,
3149                                 unpack_unreachable_expiration))
3150                         die(_("unable to add recent objects"));
3151                 if (prepare_revision_walk(&revs))
3152                         die(_("revision walk setup failed"));
3153                 traverse_commit_list(&revs, record_recent_commit,
3154                                      record_recent_object, NULL);
3155         }
3156
3157         if (keep_unreachable)
3158                 add_objects_in_unpacked_packs(&revs);
3159         if (pack_loose_unreachable)
3160                 add_unreachable_loose_objects();
3161         if (unpack_unreachable)
3162                 loosen_unused_packed_objects(&revs);
3163
3164         oid_array_clear(&recent_objects);
3165 }
3166
3167 static void add_extra_kept_packs(const struct string_list *names)
3168 {
3169         struct packed_git *p;
3170
3171         if (!names->nr)
3172                 return;
3173
3174         for (p = get_all_packs(the_repository); p; p = p->next) {
3175                 const char *name = basename(p->pack_name);
3176                 int i;
3177
3178                 if (!p->pack_local)
3179                         continue;
3180
3181                 for (i = 0; i < names->nr; i++)
3182                         if (!fspathcmp(name, names->items[i].string))
3183                                 break;
3184
3185                 if (i < names->nr) {
3186                         p->pack_keep_in_core = 1;
3187                         ignore_packed_keep_in_core = 1;
3188                         continue;
3189                 }
3190         }
3191 }
3192
3193 static int option_parse_index_version(const struct option *opt,
3194                                       const char *arg, int unset)
3195 {
3196         char *c;
3197         const char *val = arg;
3198
3199         BUG_ON_OPT_NEG(unset);
3200
3201         pack_idx_opts.version = strtoul(val, &c, 10);
3202         if (pack_idx_opts.version > 2)
3203                 die(_("unsupported index version %s"), val);
3204         if (*c == ',' && c[1])
3205                 pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
3206         if (*c || pack_idx_opts.off32_limit & 0x80000000)
3207                 die(_("bad index version '%s'"), val);
3208         return 0;
3209 }
3210
3211 static int option_parse_unpack_unreachable(const struct option *opt,
3212                                            const char *arg, int unset)
3213 {
3214         if (unset) {
3215                 unpack_unreachable = 0;
3216                 unpack_unreachable_expiration = 0;
3217         }
3218         else {
3219                 unpack_unreachable = 1;
3220                 if (arg)
3221                         unpack_unreachable_expiration = approxidate(arg);
3222         }
3223         return 0;
3224 }
3225
3226 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
3227 {
3228         int use_internal_rev_list = 0;
3229         int shallow = 0;
3230         int all_progress_implied = 0;
3231         struct argv_array rp = ARGV_ARRAY_INIT;
3232         int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
3233         int rev_list_index = 0;
3234         struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
3235         struct option pack_objects_options[] = {
3236                 OPT_SET_INT('q', "quiet", &progress,
3237                             N_("do not show progress meter"), 0),
3238                 OPT_SET_INT(0, "progress", &progress,
3239                             N_("show progress meter"), 1),
3240                 OPT_SET_INT(0, "all-progress", &progress,
3241                             N_("show progress meter during object writing phase"), 2),
3242                 OPT_BOOL(0, "all-progress-implied",
3243                          &all_progress_implied,
3244                          N_("similar to --all-progress when progress meter is shown")),
3245                 { OPTION_CALLBACK, 0, "index-version", NULL, N_("<version>[,<offset>]"),
3246                   N_("write the pack index file in the specified idx format version"),
3247                   PARSE_OPT_NONEG, option_parse_index_version },
3248                 OPT_MAGNITUDE(0, "max-pack-size", &pack_size_limit,
3249                               N_("maximum size of each output pack file")),
3250                 OPT_BOOL(0, "local", &local,
3251                          N_("ignore borrowed objects from alternate object store")),
3252                 OPT_BOOL(0, "incremental", &incremental,
3253                          N_("ignore packed objects")),
3254                 OPT_INTEGER(0, "window", &window,
3255                             N_("limit pack window by objects")),
3256                 OPT_MAGNITUDE(0, "window-memory", &window_memory_limit,
3257                               N_("limit pack window by memory in addition to object limit")),
3258                 OPT_INTEGER(0, "depth", &depth,
3259                             N_("maximum length of delta chain allowed in the resulting pack")),
3260                 OPT_BOOL(0, "reuse-delta", &reuse_delta,
3261                          N_("reuse existing deltas")),
3262                 OPT_BOOL(0, "reuse-object", &reuse_object,
3263                          N_("reuse existing objects")),
3264                 OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
3265                          N_("use OFS_DELTA objects")),
3266                 OPT_INTEGER(0, "threads", &delta_search_threads,
3267                             N_("use threads when searching for best delta matches")),
3268                 OPT_BOOL(0, "non-empty", &non_empty,
3269                          N_("do not create an empty pack output")),
3270                 OPT_BOOL(0, "revs", &use_internal_rev_list,
3271                          N_("read revision arguments from standard input")),
3272                 OPT_SET_INT_F(0, "unpacked", &rev_list_unpacked,
3273                               N_("limit the objects to those that are not yet packed"),
3274                               1, PARSE_OPT_NONEG),
3275                 OPT_SET_INT_F(0, "all", &rev_list_all,
3276                               N_("include objects reachable from any reference"),
3277                               1, PARSE_OPT_NONEG),
3278                 OPT_SET_INT_F(0, "reflog", &rev_list_reflog,
3279                               N_("include objects referred by reflog entries"),
3280                               1, PARSE_OPT_NONEG),
3281                 OPT_SET_INT_F(0, "indexed-objects", &rev_list_index,
3282                               N_("include objects referred to by the index"),
3283                               1, PARSE_OPT_NONEG),
3284                 OPT_BOOL(0, "stdout", &pack_to_stdout,
3285                          N_("output pack to stdout")),
3286                 OPT_BOOL(0, "include-tag", &include_tag,
3287                          N_("include tag objects that refer to objects to be packed")),
3288                 OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
3289                          N_("keep unreachable objects")),
3290                 OPT_BOOL(0, "pack-loose-unreachable", &pack_loose_unreachable,
3291                          N_("pack loose unreachable objects")),
3292                 { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, N_("time"),
3293                   N_("unpack unreachable objects newer than <time>"),
3294                   PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
3295                 OPT_BOOL(0, "sparse", &sparse,
3296                          N_("use the sparse reachability algorithm")),
3297                 OPT_BOOL(0, "thin", &thin,
3298                          N_("create thin packs")),
3299                 OPT_BOOL(0, "shallow", &shallow,
3300                          N_("create packs suitable for shallow fetches")),
3301                 OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep_on_disk,
3302                          N_("ignore packs that have companion .keep file")),
3303                 OPT_STRING_LIST(0, "keep-pack", &keep_pack_list, N_("name"),
3304                                 N_("ignore this pack")),
3305                 OPT_INTEGER(0, "compression", &pack_compression_level,
3306                             N_("pack compression level")),
3307                 OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
3308                             N_("do not hide commits by grafts"), 0),
3309                 OPT_BOOL(0, "use-bitmap-index", &use_bitmap_index,
3310                          N_("use a bitmap index if available to speed up counting objects")),
3311                 OPT_BOOL(0, "write-bitmap-index", &write_bitmap_index,
3312                          N_("write a bitmap index together with the pack index")),
3313                 OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
3314                 { OPTION_CALLBACK, 0, "missing", NULL, N_("action"),
3315                   N_("handling for missing objects"), PARSE_OPT_NONEG,
3316                   option_parse_missing_action },
3317                 OPT_BOOL(0, "exclude-promisor-objects", &exclude_promisor_objects,
3318                          N_("do not pack objects in promisor packfiles")),
3319                 OPT_BOOL(0, "delta-islands", &use_delta_islands,
3320                          N_("respect islands during delta compression")),
3321                 OPT_END(),
3322         };
3323
3324         if (DFS_NUM_STATES > (1 << OE_DFS_STATE_BITS))
3325                 BUG("too many dfs states, increase OE_DFS_STATE_BITS");
3326
3327         read_replace_refs = 0;
3328
3329         sparse = git_env_bool("GIT_TEST_PACK_SPARSE", 0);
3330         reset_pack_idx_option(&pack_idx_opts);
3331         git_config(git_pack_config, NULL);
3332
3333         progress = isatty(2);
3334         argc = parse_options(argc, argv, prefix, pack_objects_options,
3335                              pack_usage, 0);
3336
3337         if (argc) {
3338                 base_name = argv[0];
3339                 argc--;
3340         }
3341         if (pack_to_stdout != !base_name || argc)
3342                 usage_with_options(pack_usage, pack_objects_options);
3343
3344         if (depth >= (1 << OE_DEPTH_BITS)) {
3345                 warning(_("delta chain depth %d is too deep, forcing %d"),
3346                         depth, (1 << OE_DEPTH_BITS) - 1);
3347                 depth = (1 << OE_DEPTH_BITS) - 1;
3348         }
3349         if (cache_max_small_delta_size >= (1U << OE_Z_DELTA_BITS)) {
3350                 warning(_("pack.deltaCacheLimit is too high, forcing %d"),
3351                         (1U << OE_Z_DELTA_BITS) - 1);
3352                 cache_max_small_delta_size = (1U << OE_Z_DELTA_BITS) - 1;
3353         }
3354
3355         argv_array_push(&rp, "pack-objects");
3356         if (thin) {
3357                 use_internal_rev_list = 1;
3358                 argv_array_push(&rp, shallow
3359                                 ? "--objects-edge-aggressive"
3360                                 : "--objects-edge");
3361         } else
3362                 argv_array_push(&rp, "--objects");
3363
3364         if (rev_list_all) {
3365                 use_internal_rev_list = 1;
3366                 argv_array_push(&rp, "--all");
3367         }
3368         if (rev_list_reflog) {
3369                 use_internal_rev_list = 1;
3370                 argv_array_push(&rp, "--reflog");
3371         }
3372         if (rev_list_index) {
3373                 use_internal_rev_list = 1;
3374                 argv_array_push(&rp, "--indexed-objects");
3375         }
3376         if (rev_list_unpacked) {
3377                 use_internal_rev_list = 1;
3378                 argv_array_push(&rp, "--unpacked");
3379         }
3380
3381         if (exclude_promisor_objects) {
3382                 use_internal_rev_list = 1;
3383                 fetch_if_missing = 0;
3384                 argv_array_push(&rp, "--exclude-promisor-objects");
3385         }
3386         if (unpack_unreachable || keep_unreachable || pack_loose_unreachable)
3387                 use_internal_rev_list = 1;
3388
3389         if (!reuse_object)
3390                 reuse_delta = 0;
3391         if (pack_compression_level == -1)
3392                 pack_compression_level = Z_DEFAULT_COMPRESSION;
3393         else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
3394                 die(_("bad pack compression level %d"), pack_compression_level);
3395
3396         if (!delta_search_threads)      /* --threads=0 means autodetect */
3397                 delta_search_threads = online_cpus();
3398
3399         if (!HAVE_THREADS && delta_search_threads != 1)
3400                 warning(_("no threads support, ignoring --threads"));
3401         if (!pack_to_stdout && !pack_size_limit)
3402                 pack_size_limit = pack_size_limit_cfg;
3403         if (pack_to_stdout && pack_size_limit)
3404                 die(_("--max-pack-size cannot be used to build a pack for transfer"));
3405         if (pack_size_limit && pack_size_limit < 1024*1024) {
3406                 warning(_("minimum pack size limit is 1 MiB"));
3407                 pack_size_limit = 1024*1024;
3408         }
3409
3410         if (!pack_to_stdout && thin)
3411                 die(_("--thin cannot be used to build an indexable pack"));
3412
3413         if (keep_unreachable && unpack_unreachable)
3414                 die(_("--keep-unreachable and --unpack-unreachable are incompatible"));
3415         if (!rev_list_all || !rev_list_reflog || !rev_list_index)
3416                 unpack_unreachable_expiration = 0;
3417
3418         if (filter_options.choice) {
3419                 if (!pack_to_stdout)
3420                         die(_("cannot use --filter without --stdout"));
3421                 use_bitmap_index = 0;
3422         }
3423
3424         /*
3425          * "soft" reasons not to use bitmaps - for on-disk repack by default we want
3426          *
3427          * - to produce good pack (with bitmap index not-yet-packed objects are
3428          *   packed in suboptimal order).
3429          *
3430          * - to use more robust pack-generation codepath (avoiding possible
3431          *   bugs in bitmap code and possible bitmap index corruption).
3432          */
3433         if (!pack_to_stdout)
3434                 use_bitmap_index_default = 0;
3435
3436         if (use_bitmap_index < 0)
3437                 use_bitmap_index = use_bitmap_index_default;
3438
3439         /* "hard" reasons not to use bitmaps; these just won't work at all */
3440         if (!use_internal_rev_list || (!pack_to_stdout && write_bitmap_index) || is_repository_shallow(the_repository))
3441                 use_bitmap_index = 0;
3442
3443         if (pack_to_stdout || !rev_list_all)
3444                 write_bitmap_index = 0;
3445
3446         if (use_delta_islands)
3447                 argv_array_push(&rp, "--topo-order");
3448
3449         if (progress && all_progress_implied)
3450                 progress = 2;
3451
3452         add_extra_kept_packs(&keep_pack_list);
3453         if (ignore_packed_keep_on_disk) {
3454                 struct packed_git *p;
3455                 for (p = get_all_packs(the_repository); p; p = p->next)
3456                         if (p->pack_local && p->pack_keep)
3457                                 break;
3458                 if (!p) /* no keep-able packs found */
3459                         ignore_packed_keep_on_disk = 0;
3460         }
3461         if (local) {
3462                 /*
3463                  * unlike ignore_packed_keep_on_disk above, we do not
3464                  * want to unset "local" based on looking at packs, as
3465                  * it also covers non-local objects
3466                  */
3467                 struct packed_git *p;
3468                 for (p = get_all_packs(the_repository); p; p = p->next) {
3469                         if (!p->pack_local) {
3470                                 have_non_local_packs = 1;
3471                                 break;
3472                         }
3473                 }
3474         }
3475
3476         prepare_packing_data(the_repository, &to_pack);
3477
3478         if (progress)
3479                 progress_state = start_progress(_("Enumerating objects"), 0);
3480         if (!use_internal_rev_list)
3481                 read_object_list_from_stdin();
3482         else {
3483                 get_object_list(rp.argc, rp.argv);
3484                 argv_array_clear(&rp);
3485         }
3486         cleanup_preferred_base();
3487         if (include_tag && nr_result)
3488                 for_each_ref(add_ref_tag, NULL);
3489         stop_progress(&progress_state);
3490
3491         if (non_empty && !nr_result)
3492                 return 0;
3493         if (nr_result)
3494                 prepare_pack(window, depth);
3495         write_pack_file();
3496         if (progress)
3497                 fprintf_ln(stderr,
3498                            _("Total %"PRIu32" (delta %"PRIu32"),"
3499                              " reused %"PRIu32" (delta %"PRIu32")"),
3500                            written, written_delta, reused, reused_delta);
3501         return 0;
3502 }