git.oblomov.eu Git - git/blob - 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 "reachable.h"
  28 #include "sha1-array.h"
  29 #include "argv-array.h"
  30 #include "list.h"
  31 #include "packfile.h"
  32 #include "object-store.h"
  33
  34 static const char *pack_usage[] = {
  35         N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
  36         N_("git pack-objects [<options>...] <base-name> [< <ref-list> | < <object-list>]"),
  37         NULL
  38 };
  39
  40 /*
  41  * Objects we are going to pack are collected in the `to_pack` structure.
  42  * It contains an array (dynamically expanded) of the object data, and a map
  43  * that can resolve SHA1s to their position in the array.
  44  */
  45 static struct packing_data to_pack;
  46
  47 static struct pack_idx_entry **written_list;
  48 static uint32_t nr_result, nr_written;
  49
  50 static int non_empty;
  51 static int reuse_delta = 1, reuse_object = 1;
  52 static int keep_unreachable, unpack_unreachable, include_tag;
  53 static timestamp_t unpack_unreachable_expiration;
  54 static int pack_loose_unreachable;
  55 static int local;
  56 static int have_non_local_packs;
  57 static int incremental;
  58 static int ignore_packed_keep;
  59 static int allow_ofs_delta;
  60 static struct pack_idx_option pack_idx_opts;
  61 static const char *base_name;
  62 static int progress = 1;
  63 static int window = 10;
  64 static unsigned long pack_size_limit;
  65 static int depth = 50;
  66 static int delta_search_threads;
  67 static int pack_to_stdout;
  68 static int num_preferred_base;
  69 static struct progress *progress_state;
  70
  71 static struct packed_git *reuse_packfile;
  72 static uint32_t reuse_packfile_objects;
  73 static off_t reuse_packfile_offset;
  74
  75 static int use_bitmap_index_default = 1;
  76 static int use_bitmap_index = -1;
  77 static int write_bitmap_index;
  78 static uint16_t write_bitmap_options;
  79
  80 static int exclude_promisor_objects;
  81
  82 static unsigned long delta_cache_size = 0;
  83 static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  84 static unsigned long cache_max_small_delta_size = 1000;
  85
  86 static unsigned long window_memory_limit = 0;
  87
  88 static struct list_objects_filter_options filter_options;
  89
  90 enum missing_action {
  91         MA_ERROR = 0,      /* fail if any missing objects are encountered */
  92         MA_ALLOW_ANY,      /* silently allow ALL missing objects */
  93         MA_ALLOW_PROMISOR, /* silently allow all missing PROMISOR objects */
  94 };
  95 static enum missing_action arg_missing_action;
  96 static show_object_fn fn_show_object;
  97
  98 /*
  99  * stats
 100  */
 101 static uint32_t written, written_delta;
 102 static uint32_t reused, reused_delta;
 103
 104 /*
 105  * Indexed commits
 106  */
 107 static struct commit **indexed_commits;
 108 static unsigned int indexed_commits_nr;
 109 static unsigned int indexed_commits_alloc;
 110
 111 static void index_commit_for_bitmap(struct commit *commit)
 112 {
 113         if (indexed_commits_nr >= indexed_commits_alloc) {
 114                 indexed_commits_alloc = (indexed_commits_alloc + 32) * 2;
 115                 REALLOC_ARRAY(indexed_commits, indexed_commits_alloc);
 116         }
 117
 118         indexed_commits[indexed_commits_nr++] = commit;
 119 }
 120
 121 static void *get_delta(struct object_entry *entry)
 122 {
 123         unsigned long size, base_size, delta_size;
 124         void *buf, *base_buf, *delta_buf;
 125         enum object_type type;
 126
 127         buf = read_object_file(&entry->idx.oid, &type, &size);
 128         if (!buf)
 129                 die("unable to read %s", oid_to_hex(&entry->idx.oid));
 130         base_buf = read_object_file(&entry->delta->idx.oid, &type, &base_size);
 131         if (!base_buf)
 132                 die("unable to read %s",
 133                     oid_to_hex(&entry->delta->idx.oid));
 134         delta_buf = diff_delta(base_buf, base_size,
 135                                buf, size, &delta_size, 0);
 136         if (!delta_buf || delta_size != entry->delta_size)
 137                 die("delta size changed");
 138         free(buf);
 139         free(base_buf);
 140         return delta_buf;
 141 }
 142
 143 static unsigned long do_compress(void **pptr, unsigned long size)
 144 {
 145         git_zstream stream;
 146         void *in, *out;
 147         unsigned long maxsize;
 148
 149         git_deflate_init(&stream, pack_compression_level);
 150         maxsize = git_deflate_bound(&stream, size);
 151
 152         in = *pptr;
 153         out = xmalloc(maxsize);
 154         *pptr = out;
 155
 156         stream.next_in = in;
 157         stream.avail_in = size;
 158         stream.next_out = out;
 159         stream.avail_out = maxsize;
 160         while (git_deflate(&stream, Z_FINISH) == Z_OK)
 161                 ; /* nothing */
 162         git_deflate_end(&stream);
 163
 164         free(in);
 165         return stream.total_out;
 166 }
 167
 168 static unsigned long write_large_blob_data(struct git_istream *st, struct hashfile *f,
 169                                            const struct object_id *oid)
 170 {
 171         git_zstream stream;
 172         unsigned char ibuf[1024 * 16];
 173         unsigned char obuf[1024 * 16];
 174         unsigned long olen = 0;
 175
 176         git_deflate_init(&stream, pack_compression_level);
 177
 178         for (;;) {
 179                 ssize_t readlen;
 180                 int zret = Z_OK;
 181                 readlen = read_istream(st, ibuf, sizeof(ibuf));
 182                 if (readlen == -1)
 183                         die(_("unable to read %s"), oid_to_hex(oid));
 184
 185                 stream.next_in = ibuf;
 186                 stream.avail_in = readlen;
 187                 while ((stream.avail_in || readlen == 0) &&
 188                        (zret == Z_OK || zret == Z_BUF_ERROR)) {
 189                         stream.next_out = obuf;
 190                         stream.avail_out = sizeof(obuf);
 191                         zret = git_deflate(&stream, readlen ? 0 : Z_FINISH);
 192                         hashwrite(f, obuf, stream.next_out - obuf);
 193                         olen += stream.next_out - obuf;
 194                 }
 195                 if (stream.avail_in)
 196                         die(_("deflate error (%d)"), zret);
 197                 if (readlen == 0) {
 198                         if (zret != Z_STREAM_END)
 199                                 die(_("deflate error (%d)"), zret);
 200                         break;
 201                 }
 202         }
 203         git_deflate_end(&stream);
 204         return olen;
 205 }
 206
 207 /*
 208  * we are going to reuse the existing object data as is.  make
 209  * sure it is not corrupt.
 210  */
 211 static int check_pack_inflate(struct packed_git *p,
 212                 struct pack_window **w_curs,
 213                 off_t offset,
 214                 off_t len,
 215                 unsigned long expect)
 216 {
 217         git_zstream stream;
 218         unsigned char fakebuf[4096], *in;
 219         int st;
 220
 221         memset(&stream, 0, sizeof(stream));
 222         git_inflate_init(&stream);
 223         do {
 224                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 225                 stream.next_in = in;
 226                 stream.next_out = fakebuf;
 227                 stream.avail_out = sizeof(fakebuf);
 228                 st = git_inflate(&stream, Z_FINISH);
 229                 offset += stream.next_in - in;
 230         } while (st == Z_OK || st == Z_BUF_ERROR);
 231         git_inflate_end(&stream);
 232         return (st == Z_STREAM_END &&
 233                 stream.total_out == expect &&
 234                 stream.total_in == len) ? 0 : -1;
 235 }
 236
 237 static void copy_pack_data(struct hashfile *f,
 238                 struct packed_git *p,
 239                 struct pack_window **w_curs,
 240                 off_t offset,
 241                 off_t len)
 242 {
 243         unsigned char *in;
 244         unsigned long avail;
 245
 246         while (len) {
 247                 in = use_pack(p, w_curs, offset, &avail);
 248                 if (avail > len)
 249                         avail = (unsigned long)len;
 250                 hashwrite(f, in, avail);
 251                 offset += avail;
 252                 len -= avail;
 253         }
 254 }
 255
 256 /* Return 0 if we will bust the pack-size limit */
 257 static unsigned long write_no_reuse_object(struct hashfile *f, struct object_entry *entry,
 258                                            unsigned long limit, int usable_delta)
 259 {
 260         unsigned long size, datalen;
 261         unsigned char header[MAX_PACK_OBJECT_HEADER],
 262                       dheader[MAX_PACK_OBJECT_HEADER];
 263         unsigned hdrlen;
 264         enum object_type type;
 265         void *buf;
 266         struct git_istream *st = NULL;
 267         const unsigned hashsz = the_hash_algo->rawsz;
 268
 269         if (!usable_delta) {
 270                 if (entry->type == OBJ_BLOB &&
 271                     entry->size > big_file_threshold &&
 272                     (st = open_istream(&entry->idx.oid, &type, &size, NULL)) != NULL)
 273                         buf = NULL;
 274                 else {
 275                         buf = read_object_file(&entry->idx.oid, &type, &size);
 276                         if (!buf)
 277                                 die(_("unable to read %s"),
 278                                     oid_to_hex(&entry->idx.oid));
 279                 }
 280                 /*
 281                  * make sure no cached delta data remains from a
 282                  * previous attempt before a pack split occurred.
 283                  */
 284                 FREE_AND_NULL(entry->delta_data);
 285                 entry->z_delta_size = 0;
 286         } else if (entry->delta_data) {
 287                 size = entry->delta_size;
 288                 buf = entry->delta_data;
 289                 entry->delta_data = NULL;
 290                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 291                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 292         } else {
 293                 buf = get_delta(entry);
 294                 size = entry->delta_size;
 295                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 296                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 297         }
 298
 299         if (st) /* large blob case, just assume we don't compress well */
 300                 datalen = size;
 301         else if (entry->z_delta_size)
 302                 datalen = entry->z_delta_size;
 303         else
 304                 datalen = do_compress(&buf, size);
 305
 306         /*
 307          * The object header is a byte of 'type' followed by zero or
 308          * more bytes of length.
 309          */
 310         hdrlen = encode_in_pack_object_header(header, sizeof(header),
 311                                               type, size);
 312
 313         if (type == OBJ_OFS_DELTA) {
 314                 /*
 315                  * Deltas with relative base contain an additional
 316                  * encoding of the relative offset for the delta
 317                  * base from this object's position in the pack.
 318                  */
 319                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 320                 unsigned pos = sizeof(dheader) - 1;
 321                 dheader[pos] = ofs & 127;
 322                 while (ofs >>= 7)
 323                         dheader[--pos] = 128 | (--ofs & 127);
 324                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 325                         if (st)
 326                                 close_istream(st);
 327                         free(buf);
 328                         return 0;
 329                 }
 330                 hashwrite(f, header, hdrlen);
 331                 hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 332                 hdrlen += sizeof(dheader) - pos;
 333         } else if (type == OBJ_REF_DELTA) {
 334                 /*
 335                  * Deltas with a base reference contain
 336                  * additional bytes for the base object ID.
 337                  */
 338                 if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 339                         if (st)
 340                                 close_istream(st);
 341                         free(buf);
 342                         return 0;
 343                 }
 344                 hashwrite(f, header, hdrlen);
 345                 hashwrite(f, entry->delta->idx.oid.hash, hashsz);
 346                 hdrlen += hashsz;
 347         } else {
 348                 if (limit && hdrlen + datalen + hashsz >= limit) {
 349                         if (st)
 350                                 close_istream(st);
 351                         free(buf);
 352                         return 0;
 353                 }
 354                 hashwrite(f, header, hdrlen);
 355         }
 356         if (st) {
 357                 datalen = write_large_blob_data(st, f, &entry->idx.oid);
 358                 close_istream(st);
 359         } else {
 360                 hashwrite(f, buf, datalen);
 361                 free(buf);
 362         }
 363
 364         return hdrlen + datalen;
 365 }
 366
 367 /* Return 0 if we will bust the pack-size limit */
 368 static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 369                                 unsigned long limit, int usable_delta)
 370 {
 371         struct packed_git *p = entry->in_pack;
 372         struct pack_window *w_curs = NULL;
 373         struct revindex_entry *revidx;
 374         off_t offset;
 375         enum object_type type = entry->type;
 376         off_t datalen;
 377         unsigned char header[MAX_PACK_OBJECT_HEADER],
 378                       dheader[MAX_PACK_OBJECT_HEADER];
 379         unsigned hdrlen;
 380         const unsigned hashsz = the_hash_algo->rawsz;
 381
 382         if (entry->delta)
 383                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 384                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 385         hdrlen = encode_in_pack_object_header(header, sizeof(header),
 386                                               type, entry->size);
 387
 388         offset = entry->in_pack_offset;
 389         revidx = find_pack_revindex(p, offset);
 390         datalen = revidx[1].offset - offset;
 391         if (!pack_to_stdout && p->index_version > 1 &&
 392             check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 393                 error("bad packed object CRC for %s",
 394                       oid_to_hex(&entry->idx.oid));
 395                 unuse_pack(&w_curs);
 396                 return write_no_reuse_object(f, entry, limit, usable_delta);
 397         }
 398
 399         offset += entry->in_pack_header_size;
 400         datalen -= entry->in_pack_header_size;
 401
 402         if (!pack_to_stdout && p->index_version == 1 &&
 403             check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 404                 error("corrupt packed object for %s",
 405                       oid_to_hex(&entry->idx.oid));
 406                 unuse_pack(&w_curs);
 407                 return write_no_reuse_object(f, entry, limit, usable_delta);
 408         }
 409
 410         if (type == OBJ_OFS_DELTA) {
 411                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 412                 unsigned pos = sizeof(dheader) - 1;
 413                 dheader[pos] = ofs & 127;
 414                 while (ofs >>= 7)
 415                         dheader[--pos] = 128 | (--ofs & 127);
 416                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 417                         unuse_pack(&w_curs);
 418                         return 0;
 419                 }
 420                 hashwrite(f, header, hdrlen);
 421                 hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 422                 hdrlen += sizeof(dheader) - pos;
 423                 reused_delta++;
 424         } else if (type == OBJ_REF_DELTA) {
 425                 if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 426                         unuse_pack(&w_curs);
 427                         return 0;
 428                 }
 429                 hashwrite(f, header, hdrlen);
 430                 hashwrite(f, entry->delta->idx.oid.hash, hashsz);
 431                 hdrlen += hashsz;
 432                 reused_delta++;
 433         } else {
 434                 if (limit && hdrlen + datalen + hashsz >= limit) {
 435                         unuse_pack(&w_curs);
 436                         return 0;
 437                 }
 438                 hashwrite(f, header, hdrlen);
 439         }
 440         copy_pack_data(f, p, &w_curs, offset, datalen);
 441         unuse_pack(&w_curs);
 442         reused++;
 443         return hdrlen + datalen;
 444 }
 445
 446 /* Return 0 if we will bust the pack-size limit */
 447 static off_t write_object(struct hashfile *f,
 448                           struct object_entry *entry,
 449                           off_t write_offset)
 450 {
 451         unsigned long limit;
 452         off_t len;
 453         int usable_delta, to_reuse;
 454
 455         if (!pack_to_stdout)
 456                 crc32_begin(f);
 457
 458         /* apply size limit if limited packsize and not first object */
 459         if (!pack_size_limit || !nr_written)
 460                 limit = 0;
 461         else if (pack_size_limit <= write_offset)
 462                 /*
 463                  * the earlier object did not fit the limit; avoid
 464                  * mistaking this with unlimited (i.e. limit = 0).
 465                  */
 466                 limit = 1;
 467         else
 468                 limit = pack_size_limit - write_offset;
 469
 470         if (!entry->delta)
 471                 usable_delta = 0;       /* no delta */
 472         else if (!pack_size_limit)
 473                usable_delta = 1;        /* unlimited packfile */
 474         else if (entry->delta->idx.offset == (off_t)-1)
 475                 usable_delta = 0;       /* base was written to another pack */
 476         else if (entry->delta->idx.offset)
 477                 usable_delta = 1;       /* base already exists in this pack */
 478         else
 479                 usable_delta = 0;       /* base could end up in another pack */
 480
 481         if (!reuse_object)
 482                 to_reuse = 0;   /* explicit */
 483         else if (!entry->in_pack)
 484                 to_reuse = 0;   /* can't reuse what we don't have */
 485         else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
 486                                 /* check_object() decided it for us ... */
 487                 to_reuse = usable_delta;
 488                                 /* ... but pack split may override that */
 489         else if (entry->type != entry->in_pack_type)
 490                 to_reuse = 0;   /* pack has delta which is unusable */
 491         else if (entry->delta)
 492                 to_reuse = 0;   /* we want to pack afresh */
 493         else
 494                 to_reuse = 1;   /* we have it in-pack undeltified,
 495                                  * and we do not need to deltify it.
 496                                  */
 497
 498         if (!to_reuse)
 499                 len = write_no_reuse_object(f, entry, limit, usable_delta);
 500         else
 501                 len = write_reuse_object(f, entry, limit, usable_delta);
 502         if (!len)
 503                 return 0;
 504
 505         if (usable_delta)
 506                 written_delta++;
 507         written++;
 508         if (!pack_to_stdout)
 509                 entry->idx.crc32 = crc32_end(f);
 510         return len;
 511 }
 512
 513 enum write_one_status {
 514         WRITE_ONE_SKIP = -1, /* already written */
 515         WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 516         WRITE_ONE_WRITTEN = 1, /* normal */
 517         WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 518 };
 519
 520 static enum write_one_status write_one(struct hashfile *f,
 521                                        struct object_entry *e,
 522                                        off_t *offset)
 523 {
 524         off_t size;
 525         int recursing;
 526
 527         /*
 528          * we set offset to 1 (which is an impossible value) to mark
 529          * the fact that this object is involved in "write its base
 530          * first before writing a deltified object" recursion.
 531          */
 532         recursing = (e->idx.offset == 1);
 533         if (recursing) {
 534                 warning("recursive delta detected for object %s",
 535                         oid_to_hex(&e->idx.oid));
 536                 return WRITE_ONE_RECURSIVE;
 537         } else if (e->idx.offset || e->preferred_base) {
 538                 /* offset is non zero if object is written already. */
 539                 return WRITE_ONE_SKIP;
 540         }
 541
 542         /* if we are deltified, write out base object first. */
 543         if (e->delta) {
 544                 e->idx.offset = 1; /* now recurse */
 545                 switch (write_one(f, e->delta, offset)) {
 546                 case WRITE_ONE_RECURSIVE:
 547                         /* we cannot depend on this one */
 548                         e->delta = NULL;
 549                         break;
 550                 default:
 551                         break;
 552                 case WRITE_ONE_BREAK:
 553                         e->idx.offset = recursing;
 554                         return WRITE_ONE_BREAK;
 555                 }
 556         }
 557
 558         e->idx.offset = *offset;
 559         size = write_object(f, e, *offset);
 560         if (!size) {
 561                 e->idx.offset = recursing;
 562                 return WRITE_ONE_BREAK;
 563         }
 564         written_list[nr_written++] = &e->idx;
 565
 566         /* make sure off_t is sufficiently large not to wrap */
 567         if (signed_add_overflows(*offset, size))
 568                 die("pack too large for current definition of off_t");
 569         *offset += size;
 570         return WRITE_ONE_WRITTEN;
 571 }
 572
 573 static int mark_tagged(const char *path, const struct object_id *oid, int flag,
 574                        void *cb_data)
 575 {
 576         struct object_id peeled;
 577         struct object_entry *entry = packlist_find(&to_pack, oid->hash, NULL);
 578
 579         if (entry)
 580                 entry->tagged = 1;
 581         if (!peel_ref(path, &peeled)) {
 582                 entry = packlist_find(&to_pack, peeled.hash, NULL);
 583                 if (entry)
 584                         entry->tagged = 1;
 585         }
 586         return 0;
 587 }
 588
 589 static inline void add_to_write_order(struct object_entry **wo,
 590                                unsigned int *endp,
 591                                struct object_entry *e)
 592 {
 593         if (e->filled)
 594                 return;
 595         wo[(*endp)++] = e;
 596         e->filled = 1;
 597 }
 598
 599 static void add_descendants_to_write_order(struct object_entry **wo,
 600                                            unsigned int *endp,
 601                                            struct object_entry *e)
 602 {
 603         int add_to_order = 1;
 604         while (e) {
 605                 if (add_to_order) {
 606                         struct object_entry *s;
 607                         /* add this node... */
 608                         add_to_write_order(wo, endp, e);
 609                         /* all its siblings... */
 610                         for (s = e->delta_sibling; s; s = s->delta_sibling) {
 611                                 add_to_write_order(wo, endp, s);
 612                         }
 613                 }
 614                 /* drop down a level to add left subtree nodes if possible */
 615                 if (e->delta_child) {
 616                         add_to_order = 1;
 617                         e = e->delta_child;
 618                 } else {
 619                         add_to_order = 0;
 620                         /* our sibling might have some children, it is next */
 621                         if (e->delta_sibling) {
 622                                 e = e->delta_sibling;
 623                                 continue;
 624                         }
 625                         /* go back to our parent node */
 626                         e = e->delta;
 627                         while (e && !e->delta_sibling) {
 628                                 /* we're on the right side of a subtree, keep
 629                                  * going up until we can go right again */
 630                                 e = e->delta;
 631                         }
 632                         if (!e) {
 633                                 /* done- we hit our original root node */
 634                                 return;
 635                         }
 636                         /* pass it off to sibling at this level */
 637                         e = e->delta_sibling;
 638                 }
 639         };
 640 }
 641
 642 static void add_family_to_write_order(struct object_entry **wo,
 643                                       unsigned int *endp,
 644                                       struct object_entry *e)
 645 {
 646         struct object_entry *root;
 647
 648         for (root = e; root->delta; root = root->delta)
 649                 ; /* nothing */
 650         add_descendants_to_write_order(wo, endp, root);
 651 }
 652
 653 static struct object_entry **compute_write_order(void)
 654 {
 655         unsigned int i, wo_end, last_untagged;
 656
 657         struct object_entry **wo;
 658         struct object_entry *objects = to_pack.objects;
 659
 660         for (i = 0; i < to_pack.nr_objects; i++) {
 661                 objects[i].tagged = 0;
 662                 objects[i].filled = 0;
 663                 objects[i].delta_child = NULL;
 664                 objects[i].delta_sibling = NULL;
 665         }
 666
 667         /*
 668          * Fully connect delta_child/delta_sibling network.
 669          * Make sure delta_sibling is sorted in the original
 670          * recency order.
 671          */
 672         for (i = to_pack.nr_objects; i > 0;) {
 673                 struct object_entry *e = &objects[--i];
 674                 if (!e->delta)
 675                         continue;
 676                 /* Mark me as the first child */
 677                 e->delta_sibling = e->delta->delta_child;
 678                 e->delta->delta_child = e;
 679         }
 680
 681         /*
 682          * Mark objects that are at the tip of tags.
 683          */
 684         for_each_tag_ref(mark_tagged, NULL);
 685
 686         /*
 687          * Give the objects in the original recency order until
 688          * we see a tagged tip.
 689          */
 690         ALLOC_ARRAY(wo, to_pack.nr_objects);
 691         for (i = wo_end = 0; i < to_pack.nr_objects; i++) {
 692                 if (objects[i].tagged)
 693                         break;
 694                 add_to_write_order(wo, &wo_end, &objects[i]);
 695         }
 696         last_untagged = i;
 697
 698         /*
 699          * Then fill all the tagged tips.
 700          */
 701         for (; i < to_pack.nr_objects; i++) {
 702                 if (objects[i].tagged)
 703                         add_to_write_order(wo, &wo_end, &objects[i]);
 704         }
 705
 706         /*
 707          * And then all remaining commits and tags.
 708          */
 709         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 710                 if (objects[i].type != OBJ_COMMIT &&
 711                     objects[i].type != OBJ_TAG)
 712                         continue;
 713                 add_to_write_order(wo, &wo_end, &objects[i]);
 714         }
 715
 716         /*
 717          * And then all the trees.
 718          */
 719         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 720                 if (objects[i].type != OBJ_TREE)
 721                         continue;
 722                 add_to_write_order(wo, &wo_end, &objects[i]);
 723         }
 724
 725         /*
 726          * Finally all the rest in really tight order
 727          */
 728         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 729                 if (!objects[i].filled)
 730                         add_family_to_write_order(wo, &wo_end, &objects[i]);
 731         }
 732
 733         if (wo_end != to_pack.nr_objects)
 734                 die("ordered %u objects, expected %"PRIu32, wo_end, to_pack.nr_objects);
 735
 736         return wo;
 737 }
 738
 739 static off_t write_reused_pack(struct hashfile *f)
 740 {
 741         unsigned char buffer[8192];
 742         off_t to_write, total;
 743         int fd;
 744
 745         if (!is_pack_valid(reuse_packfile))
 746                 die("packfile is invalid: %s", reuse_packfile->pack_name);
 747
 748         fd = git_open(reuse_packfile->pack_name);
 749         if (fd < 0)
 750                 die_errno("unable to open packfile for reuse: %s",
 751                           reuse_packfile->pack_name);
 752
 753         if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
 754                 die_errno("unable to seek in reused packfile");
 755
 756         if (reuse_packfile_offset < 0)
 757                 reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
 758
 759         total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 760
 761         while (to_write) {
 762                 int read_pack = xread(fd, buffer, sizeof(buffer));
 763
 764                 if (read_pack <= 0)
 765                         die_errno("unable to read from reused packfile");
 766
 767                 if (read_pack > to_write)
 768                         read_pack = to_write;
 769
 770                 hashwrite(f, buffer, read_pack);
 771                 to_write -= read_pack;
 772
 773                 /*
 774                  * We don't know the actual number of objects written,
 775                  * only how many bytes written, how many bytes total, and
 776                  * how many objects total. So we can fake it by pretending all
 777                  * objects we are writing are the same size. This gives us a
 778                  * smooth progress meter, and at the end it matches the true
 779                  * answer.
 780                  */
 781                 written = reuse_packfile_objects *
 782                                 (((double)(total - to_write)) / total);
 783                 display_progress(progress_state, written);
 784         }
 785
 786         close(fd);
 787         written = reuse_packfile_objects;
 788         display_progress(progress_state, written);
 789         return reuse_packfile_offset - sizeof(struct pack_header);
 790 }
 791
 792 static const char no_split_warning[] = N_(
 793 "disabling bitmap writing, packs are split due to pack.packSizeLimit"
 794 );
 795
 796 static void write_pack_file(void)
 797 {
 798         uint32_t i = 0, j;
 799         struct hashfile *f;
 800         off_t offset;
 801         uint32_t nr_remaining = nr_result;
 802         time_t last_mtime = 0;
 803         struct object_entry **write_order;
 804
 805         if (progress > pack_to_stdout)
 806                 progress_state = start_progress(_("Writing objects"), nr_result);
 807         ALLOC_ARRAY(written_list, to_pack.nr_objects);
 808         write_order = compute_write_order();
 809
 810         do {
 811                 struct object_id oid;
 812                 char *pack_tmp_name = NULL;
 813
 814                 if (pack_to_stdout)
 815                         f = hashfd_throughput(1, "<stdout>", progress_state);
 816                 else
 817                         f = create_tmp_packfile(&pack_tmp_name);
 818
 819                 offset = write_pack_header(f, nr_remaining);
 820
 821                 if (reuse_packfile) {
 822                         off_t packfile_size;
 823                         assert(pack_to_stdout);
 824
 825                         packfile_size = write_reused_pack(f);
 826                         offset += packfile_size;
 827                 }
 828
 829                 nr_written = 0;
 830                 for (; i < to_pack.nr_objects; i++) {
 831                         struct object_entry *e = write_order[i];
 832                         if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 833                                 break;
 834                         display_progress(progress_state, written);
 835                 }
 836
 837                 /*
 838                  * Did we write the wrong # entries in the header?
 839                  * If so, rewrite it like in fast-import
 840                  */
 841                 if (pack_to_stdout) {
 842                         hashclose(f, oid.hash, CSUM_CLOSE);
 843                 } else if (nr_written == nr_remaining) {
 844                         hashclose(f, oid.hash, CSUM_FSYNC);
 845                 } else {
 846                         int fd = hashclose(f, oid.hash, 0);
 847                         fixup_pack_header_footer(fd, oid.hash, pack_tmp_name,
 848                                                  nr_written, oid.hash, offset);
 849                         close(fd);
 850                         if (write_bitmap_index) {
 851                                 warning(_(no_split_warning));
 852                                 write_bitmap_index = 0;
 853                         }
 854                 }
 855
 856                 if (!pack_to_stdout) {
 857                         struct stat st;
 858                         struct strbuf tmpname = STRBUF_INIT;
 859
 860                         /*
 861                          * Packs are runtime accessed in their mtime
 862                          * order since newer packs are more likely to contain
 863                          * younger objects.  So if we are creating multiple
 864                          * packs then we should modify the mtime of later ones
 865                          * to preserve this property.
 866                          */
 867                         if (stat(pack_tmp_name, &st) < 0) {
 868                                 warning_errno("failed to stat %s", pack_tmp_name);
 869                         } else if (!last_mtime) {
 870                                 last_mtime = st.st_mtime;
 871                         } else {
 872                                 struct utimbuf utb;
 873                                 utb.actime = st.st_atime;
 874                                 utb.modtime = --last_mtime;
 875                                 if (utime(pack_tmp_name, &utb) < 0)
 876                                         warning_errno("failed utime() on %s", pack_tmp_name);
 877                         }
 878
 879                         strbuf_addf(&tmpname, "%s-", base_name);
 880
 881                         if (write_bitmap_index) {
 882                                 bitmap_writer_set_checksum(oid.hash);
 883                                 bitmap_writer_build_type_index(written_list, nr_written);
 884                         }
 885
 886                         finish_tmp_packfile(&tmpname, pack_tmp_name,
 887                                             written_list, nr_written,
 888                                             &pack_idx_opts, oid.hash);
 889
 890                         if (write_bitmap_index) {
 891                                 strbuf_addf(&tmpname, "%s.bitmap", oid_to_hex(&oid));
 892
 893                                 stop_progress(&progress_state);
 894
 895                                 bitmap_writer_show_progress(progress);
 896                                 bitmap_writer_reuse_bitmaps(&to_pack);
 897                                 bitmap_writer_select_commits(indexed_commits, indexed_commits_nr, -1);
 898                                 bitmap_writer_build(&to_pack);
 899                                 bitmap_writer_finish(written_list, nr_written,
 900                                                      tmpname.buf, write_bitmap_options);
 901                                 write_bitmap_index = 0;
 902                         }
 903
 904                         strbuf_release(&tmpname);
 905                         free(pack_tmp_name);
 906                         puts(oid_to_hex(&oid));
 907                 }
 908
 909                 /* mark written objects as written to previous pack */
 910                 for (j = 0; j < nr_written; j++) {
 911                         written_list[j]->offset = (off_t)-1;
 912                 }
 913                 nr_remaining -= nr_written;
 914         } while (nr_remaining && i < to_pack.nr_objects);
 915
 916         free(written_list);
 917         free(write_order);
 918         stop_progress(&progress_state);
 919         if (written != nr_result)
 920                 die("wrote %"PRIu32" objects while expecting %"PRIu32,
 921                         written, nr_result);
 922 }
 923
 924 static int no_try_delta(const char *path)
 925 {
 926         static struct attr_check *check;
 927
 928         if (!check)
 929                 check = attr_check_initl("delta", NULL);
 930         if (git_check_attr(path, check))
 931                 return 0;
 932         if (ATTR_FALSE(check->items[0].value))
 933                 return 1;
 934         return 0;
 935 }
 936
 937 /*
 938  * When adding an object, check whether we have already added it
 939  * to our packing list. If so, we can skip. However, if we are
 940  * being asked to excludei t, but the previous mention was to include
 941  * it, make sure to adjust its flags and tweak our numbers accordingly.
 942  *
 943  * As an optimization, we pass out the index position where we would have
 944  * found the item, since that saves us from having to look it up again a
 945  * few lines later when we want to add the new entry.
 946  */
 947 static int have_duplicate_entry(const struct object_id *oid,
 948                                 int exclude,
 949                                 uint32_t *index_pos)
 950 {
 951         struct object_entry *entry;
 952
 953         entry = packlist_find(&to_pack, oid->hash, index_pos);
 954         if (!entry)
 955                 return 0;
 956
 957         if (exclude) {
 958                 if (!entry->preferred_base)
 959                         nr_result--;
 960                 entry->preferred_base = 1;
 961         }
 962
 963         return 1;
 964 }
 965
 966 static int want_found_object(int exclude, struct packed_git *p)
 967 {
 968         if (exclude)
 969                 return 1;
 970         if (incremental)
 971                 return 0;
 972
 973         /*
 974          * When asked to do --local (do not include an object that appears in a
 975          * pack we borrow from elsewhere) or --honor-pack-keep (do not include
 976          * an object that appears in a pack marked with .keep), finding a pack
 977          * that matches the criteria is sufficient for us to decide to omit it.
 978          * However, even if this pack does not satisfy the criteria, we need to
 979          * make sure no copy of this object appears in _any_ pack that makes us
 980          * to omit the object, so we need to check all the packs.
 981          *
 982          * We can however first check whether these options can possible matter;
 983          * if they do not matter we know we want the object in generated pack.
 984          * Otherwise, we signal "-1" at the end to tell the caller that we do
 985          * not know either way, and it needs to check more packs.
 986          */
 987         if (!ignore_packed_keep &&
 988             (!local || !have_non_local_packs))
 989                 return 1;
 990
 991         if (local && !p->pack_local)
 992                 return 0;
 993         if (ignore_packed_keep && p->pack_local && p->pack_keep)
 994                 return 0;
 995
 996         /* we don't know yet; keep looking for more packs */
 997         return -1;
 998 }
 999
1000 /*
1001  * Check whether we want the object in the pack (e.g., we do not want
1002  * objects found in non-local stores if the "--local" option was used).
1003  *
1004  * If the caller already knows an existing pack it wants to take the object
1005  * from, that is passed in *found_pack and *found_offset; otherwise this
1006  * function finds if there is any pack that has the object and returns the pack
1007  * and its offset in these variables.
1008  */
1009 static int want_object_in_pack(const struct object_id *oid,
1010                                int exclude,
1011                                struct packed_git **found_pack,
1012                                off_t *found_offset)
1013 {
1014         int want;
1015         struct list_head *pos;
1016
1017         if (!exclude && local && has_loose_object_nonlocal(oid))
1018                 return 0;
1019
1020         /*
1021          * If we already know the pack object lives in, start checks from that
1022          * pack - in the usual case when neither --local was given nor .keep files
1023          * are present we will determine the answer right now.
1024          */
1025         if (*found_pack) {
1026                 want = want_found_object(exclude, *found_pack);
1027                 if (want != -1)
1028                         return want;
1029         }
1030         list_for_each(pos, get_packed_git_mru(the_repository)) {
1031                 struct packed_git *p = list_entry(pos, struct packed_git, mru);
1032                 off_t offset;
1033
1034                 if (p == *found_pack)
1035                         offset = *found_offset;
1036                 else
1037                         offset = find_pack_entry_one(oid->hash, p);
1038
1039                 if (offset) {
1040                         if (!*found_pack) {
1041                                 if (!is_pack_valid(p))
1042                                         continue;
1043                                 *found_offset = offset;
1044                                 *found_pack = p;
1045                         }
1046                         want = want_found_object(exclude, p);
1047                         if (!exclude && want > 0)
1048                                 list_move(&p->mru,
1049                                           get_packed_git_mru(the_repository));
1050                         if (want != -1)
1051                                 return want;
1052                 }
1053         }
1054
1055         return 1;
1056 }
1057
1058 static void create_object_entry(const struct object_id *oid,
1059                                 enum object_type type,
1060                                 uint32_t hash,
1061                                 int exclude,
1062                                 int no_try_delta,
1063                                 uint32_t index_pos,
1064                                 struct packed_git *found_pack,
1065                                 off_t found_offset)
1066 {
1067         struct object_entry *entry;
1068
1069         entry = packlist_alloc(&to_pack, oid->hash, index_pos);
1070         entry->hash = hash;
1071         if (type)
1072                 entry->type = type;
1073         if (exclude)
1074                 entry->preferred_base = 1;
1075         else
1076                 nr_result++;
1077         if (found_pack) {
1078                 entry->in_pack = found_pack;
1079                 entry->in_pack_offset = found_offset;
1080         }
1081
1082         entry->no_try_delta = no_try_delta;
1083 }
1084
1085 static const char no_closure_warning[] = N_(
1086 "disabling bitmap writing, as some objects are not being packed"
1087 );
1088
1089 static int add_object_entry(const struct object_id *oid, enum object_type type,
1090                             const char *name, int exclude)
1091 {
1092         struct packed_git *found_pack = NULL;
1093         off_t found_offset = 0;
1094         uint32_t index_pos;
1095
1096         if (have_duplicate_entry(oid, exclude, &index_pos))
1097                 return 0;
1098
1099         if (!want_object_in_pack(oid, exclude, &found_pack, &found_offset)) {
1100                 /* The pack is missing an object, so it will not have closure */
1101                 if (write_bitmap_index) {
1102                         warning(_(no_closure_warning));
1103                         write_bitmap_index = 0;
1104                 }
1105                 return 0;
1106         }
1107
1108         create_object_entry(oid, type, pack_name_hash(name),
1109                             exclude, name && no_try_delta(name),
1110                             index_pos, found_pack, found_offset);
1111
1112         display_progress(progress_state, nr_result);
1113         return 1;
1114 }
1115
1116 static int add_object_entry_from_bitmap(const struct object_id *oid,
1117                                         enum object_type type,
1118                                         int flags, uint32_t name_hash,
1119                                         struct packed_git *pack, off_t offset)
1120 {
1121         uint32_t index_pos;
1122
1123         if (have_duplicate_entry(oid, 0, &index_pos))
1124                 return 0;
1125
1126         if (!want_object_in_pack(oid, 0, &pack, &offset))
1127                 return 0;
1128
1129         create_object_entry(oid, type, name_hash, 0, 0, index_pos, pack, offset);
1130
1131         display_progress(progress_state, nr_result);
1132         return 1;
1133 }
1134
1135 struct pbase_tree_cache {
1136         struct object_id oid;
1137         int ref;
1138         int temporary;
1139         void *tree_data;
1140         unsigned long tree_size;
1141 };
1142
1143 static struct pbase_tree_cache *(pbase_tree_cache[256]);
1144 static int pbase_tree_cache_ix(const struct object_id *oid)
1145 {
1146         return oid->hash[0] % ARRAY_SIZE(pbase_tree_cache);
1147 }
1148 static int pbase_tree_cache_ix_incr(int ix)
1149 {
1150         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
1151 }
1152
1153 static struct pbase_tree {
1154         struct pbase_tree *next;
1155         /* This is a phony "cache" entry; we are not
1156          * going to evict it or find it through _get()
1157          * mechanism -- this is for the toplevel node that
1158          * would almost always change with any commit.
1159          */
1160         struct pbase_tree_cache pcache;
1161 } *pbase_tree;
1162
1163 static struct pbase_tree_cache *pbase_tree_get(const struct object_id *oid)
1164 {
1165         struct pbase_tree_cache *ent, *nent;
1166         void *data;
1167         unsigned long size;
1168         enum object_type type;
1169         int neigh;
1170         int my_ix = pbase_tree_cache_ix(oid);
1171         int available_ix = -1;
1172
1173         /* pbase-tree-cache acts as a limited hashtable.
1174          * your object will be found at your index or within a few
1175          * slots after that slot if it is cached.
1176          */
1177         for (neigh = 0; neigh < 8; neigh++) {
1178                 ent = pbase_tree_cache[my_ix];
1179                 if (ent && !oidcmp(&ent->oid, oid)) {
1180                         ent->ref++;
1181                         return ent;
1182                 }
1183                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
1184                          ((0 <= available_ix) &&
1185                           (!ent && pbase_tree_cache[available_ix])))
1186                         available_ix = my_ix;
1187                 if (!ent)
1188                         break;
1189                 my_ix = pbase_tree_cache_ix_incr(my_ix);
1190         }
1191
1192         /* Did not find one.  Either we got a bogus request or
1193          * we need to read and perhaps cache.
1194          */
1195         data = read_object_file(oid, &type, &size);
1196         if (!data)
1197                 return NULL;
1198         if (type != OBJ_TREE) {
1199                 free(data);
1200                 return NULL;
1201         }
1202
1203         /* We need to either cache or return a throwaway copy */
1204
1205         if (available_ix < 0)
1206                 ent = NULL;
1207         else {
1208                 ent = pbase_tree_cache[available_ix];
1209                 my_ix = available_ix;
1210         }
1211
1212         if (!ent) {
1213                 nent = xmalloc(sizeof(*nent));
1214                 nent->temporary = (available_ix < 0);
1215         }
1216         else {
1217                 /* evict and reuse */
1218                 free(ent->tree_data);
1219                 nent = ent;
1220         }
1221         oidcpy(&nent->oid, oid);
1222         nent->tree_data = data;
1223         nent->tree_size = size;
1224         nent->ref = 1;
1225         if (!nent->temporary)
1226                 pbase_tree_cache[my_ix] = nent;
1227         return nent;
1228 }
1229
1230 static void pbase_tree_put(struct pbase_tree_cache *cache)
1231 {
1232         if (!cache->temporary) {
1233                 cache->ref--;
1234                 return;
1235         }
1236         free(cache->tree_data);
1237         free(cache);
1238 }
1239
1240 static int name_cmp_len(const char *name)
1241 {
1242         int i;
1243         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1244                 ;
1245         return i;
1246 }
1247
1248 static void add_pbase_object(struct tree_desc *tree,
1249                              const char *name,
1250                              int cmplen,
1251                              const char *fullname)
1252 {
1253         struct name_entry entry;
1254         int cmp;
1255
1256         while (tree_entry(tree,&entry)) {
1257                 if (S_ISGITLINK(entry.mode))
1258                         continue;
1259                 cmp = tree_entry_len(&entry) != cmplen ? 1 :
1260                       memcmp(name, entry.path, cmplen);
1261                 if (cmp > 0)
1262                         continue;
1263                 if (cmp < 0)
1264                         return;
1265                 if (name[cmplen] != '/') {
1266                         add_object_entry(entry.oid,
1267                                          object_type(entry.mode),
1268                                          fullname, 1);
1269                         return;
1270                 }
1271                 if (S_ISDIR(entry.mode)) {
1272                         struct tree_desc sub;
1273                         struct pbase_tree_cache *tree;
1274                         const char *down = name+cmplen+1;
1275                         int downlen = name_cmp_len(down);
1276
1277                         tree = pbase_tree_get(entry.oid);
1278                         if (!tree)
1279                                 return;
1280                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1281
1282                         add_pbase_object(&sub, down, downlen, fullname);
1283                         pbase_tree_put(tree);
1284                 }
1285         }
1286 }
1287
1288 static unsigned *done_pbase_paths;
1289 static int done_pbase_paths_num;
1290 static int done_pbase_paths_alloc;
1291 static int done_pbase_path_pos(unsigned hash)
1292 {
1293         int lo = 0;
1294         int hi = done_pbase_paths_num;
1295         while (lo < hi) {
1296                 int mi = lo + (hi - lo) / 2;
1297                 if (done_pbase_paths[mi] == hash)
1298                         return mi;
1299                 if (done_pbase_paths[mi] < hash)
1300                         hi = mi;
1301                 else
1302                         lo = mi + 1;
1303         }
1304         return -lo-1;
1305 }
1306
1307 static int check_pbase_path(unsigned hash)
1308 {
1309         int pos = done_pbase_path_pos(hash);
1310         if (0 <= pos)
1311                 return 1;
1312         pos = -pos - 1;
1313         ALLOC_GROW(done_pbase_paths,
1314                    done_pbase_paths_num + 1,
1315                    done_pbase_paths_alloc);
1316         done_pbase_paths_num++;
1317         if (pos < done_pbase_paths_num)
1318                 MOVE_ARRAY(done_pbase_paths + pos + 1, done_pbase_paths + pos,
1319                            done_pbase_paths_num - pos - 1);
1320         done_pbase_paths[pos] = hash;
1321         return 0;
1322 }
1323
1324 static void add_preferred_base_object(const char *name)
1325 {
1326         struct pbase_tree *it;
1327         int cmplen;
1328         unsigned hash = pack_name_hash(name);
1329
1330         if (!num_preferred_base || check_pbase_path(hash))
1331                 return;
1332
1333         cmplen = name_cmp_len(name);
1334         for (it = pbase_tree; it; it = it->next) {
1335                 if (cmplen == 0) {
1336                         add_object_entry(&it->pcache.oid, OBJ_TREE, NULL, 1);
1337                 }
1338                 else {
1339                         struct tree_desc tree;
1340                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1341                         add_pbase_object(&tree, name, cmplen, name);
1342                 }
1343         }
1344 }
1345
1346 static void add_preferred_base(struct object_id *oid)
1347 {
1348         struct pbase_tree *it;
1349         void *data;
1350         unsigned long size;
1351         struct object_id tree_oid;
1352
1353         if (window <= num_preferred_base++)
1354                 return;
1355
1356         data = read_object_with_reference(oid, tree_type, &size, &tree_oid);
1357         if (!data)
1358                 return;
1359
1360         for (it = pbase_tree; it; it = it->next) {
1361                 if (!oidcmp(&it->pcache.oid, &tree_oid)) {
1362                         free(data);
1363                         return;
1364                 }
1365         }
1366
1367         it = xcalloc(1, sizeof(*it));
1368         it->next = pbase_tree;
1369         pbase_tree = it;
1370
1371         oidcpy(&it->pcache.oid, &tree_oid);
1372         it->pcache.tree_data = data;
1373         it->pcache.tree_size = size;
1374 }
1375
1376 static void cleanup_preferred_base(void)
1377 {
1378         struct pbase_tree *it;
1379         unsigned i;
1380
1381         it = pbase_tree;
1382         pbase_tree = NULL;
1383         while (it) {
1384                 struct pbase_tree *tmp = it;
1385                 it = tmp->next;
1386                 free(tmp->pcache.tree_data);
1387                 free(tmp);
1388         }
1389
1390         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1391                 if (!pbase_tree_cache[i])
1392                         continue;
1393                 free(pbase_tree_cache[i]->tree_data);
1394                 FREE_AND_NULL(pbase_tree_cache[i]);
1395         }
1396
1397         FREE_AND_NULL(done_pbase_paths);
1398         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1399 }
1400
1401 static void check_object(struct object_entry *entry)
1402 {
1403         if (entry->in_pack) {
1404                 struct packed_git *p = entry->in_pack;
1405                 struct pack_window *w_curs = NULL;
1406                 const unsigned char *base_ref = NULL;
1407                 struct object_entry *base_entry;
1408                 unsigned long used, used_0;
1409                 unsigned long avail;
1410                 off_t ofs;
1411                 unsigned char *buf, c;
1412
1413                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1414
1415                 /*
1416                  * We want in_pack_type even if we do not reuse delta
1417                  * since non-delta representations could still be reused.
1418                  */
1419                 used = unpack_object_header_buffer(buf, avail,
1420                                                    &entry->in_pack_type,
1421                                                    &entry->size);
1422                 if (used == 0)
1423                         goto give_up;
1424
1425                 /*
1426                  * Determine if this is a delta and if so whether we can
1427                  * reuse it or not.  Otherwise let's find out as cheaply as
1428                  * possible what the actual type and size for this object is.
1429                  */
1430                 switch (entry->in_pack_type) {
1431                 default:
1432                         /* Not a delta hence we've already got all we need. */
1433                         entry->type = entry->in_pack_type;
1434                         entry->in_pack_header_size = used;
1435                         if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1436                                 goto give_up;
1437                         unuse_pack(&w_curs);
1438                         return;
1439                 case OBJ_REF_DELTA:
1440                         if (reuse_delta && !entry->preferred_base)
1441                                 base_ref = use_pack(p, &w_curs,
1442                                                 entry->in_pack_offset + used, NULL);
1443                         entry->in_pack_header_size = used + the_hash_algo->rawsz;
1444                         break;
1445                 case OBJ_OFS_DELTA:
1446                         buf = use_pack(p, &w_curs,
1447                                        entry->in_pack_offset + used, NULL);
1448                         used_0 = 0;
1449                         c = buf[used_0++];
1450                         ofs = c & 127;
1451                         while (c & 128) {
1452                                 ofs += 1;
1453                                 if (!ofs || MSB(ofs, 7)) {
1454                                         error("delta base offset overflow in pack for %s",
1455                                               oid_to_hex(&entry->idx.oid));
1456                                         goto give_up;
1457                                 }
1458                                 c = buf[used_0++];
1459                                 ofs = (ofs << 7) + (c & 127);
1460                         }
1461                         ofs = entry->in_pack_offset - ofs;
1462                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1463                                 error("delta base offset out of bound for %s",
1464                                       oid_to_hex(&entry->idx.oid));
1465                                 goto give_up;
1466                         }
1467                         if (reuse_delta && !entry->preferred_base) {
1468                                 struct revindex_entry *revidx;
1469                                 revidx = find_pack_revindex(p, ofs);
1470                                 if (!revidx)
1471                                         goto give_up;
1472                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1473                         }
1474                         entry->in_pack_header_size = used + used_0;
1475                         break;
1476                 }
1477
1478                 if (base_ref && (base_entry = packlist_find(&to_pack, base_ref, NULL))) {
1479                         /*
1480                          * If base_ref was set above that means we wish to
1481                          * reuse delta data, and we even found that base
1482                          * in the list of objects we want to pack. Goodie!
1483                          *
1484                          * Depth value does not matter - find_deltas() will
1485                          * never consider reused delta as the base object to
1486                          * deltify other objects against, in order to avoid
1487                          * circular deltas.
1488                          */
1489                         entry->type = entry->in_pack_type;
1490                         entry->delta = base_entry;
1491                         entry->delta_size = entry->size;
1492                         entry->delta_sibling = base_entry->delta_child;
1493                         base_entry->delta_child = entry;
1494                         unuse_pack(&w_curs);
1495                         return;
1496                 }
1497
1498                 if (entry->type) {
1499                         /*
1500                          * This must be a delta and we already know what the
1501                          * final object type is.  Let's extract the actual
1502                          * object size from the delta header.
1503                          */
1504                         entry->size = get_size_from_delta(p, &w_curs,
1505                                         entry->in_pack_offset + entry->in_pack_header_size);
1506                         if (entry->size == 0)
1507                                 goto give_up;
1508                         unuse_pack(&w_curs);
1509                         return;
1510                 }
1511
1512                 /*
1513                  * No choice but to fall back to the recursive delta walk
1514                  * with sha1_object_info() to find about the object type
1515                  * at this point...
1516                  */
1517                 give_up:
1518                 unuse_pack(&w_curs);
1519         }
1520
1521         entry->type = oid_object_info(&entry->idx.oid, &entry->size);
1522         /*
1523          * The error condition is checked in prepare_pack().  This is
1524          * to permit a missing preferred base object to be ignored
1525          * as a preferred base.  Doing so can result in a larger
1526          * pack file, but the transfer will still take place.
1527          */
1528 }
1529
1530 static int pack_offset_sort(const void *_a, const void *_b)
1531 {
1532         const struct object_entry *a = *(struct object_entry **)_a;
1533         const struct object_entry *b = *(struct object_entry **)_b;
1534
1535         /* avoid filesystem trashing with loose objects */
1536         if (!a->in_pack && !b->in_pack)
1537                 return oidcmp(&a->idx.oid, &b->idx.oid);
1538
1539         if (a->in_pack < b->in_pack)
1540                 return -1;
1541         if (a->in_pack > b->in_pack)
1542                 return 1;
1543         return a->in_pack_offset < b->in_pack_offset ? -1 :
1544                         (a->in_pack_offset > b->in_pack_offset);
1545 }
1546
1547 /*
1548  * Drop an on-disk delta we were planning to reuse. Naively, this would
1549  * just involve blanking out the "delta" field, but we have to deal
1550  * with some extra book-keeping:
1551  *
1552  *   1. Removing ourselves from the delta_sibling linked list.
1553  *
1554  *   2. Updating our size/type to the non-delta representation. These were
1555  *      either not recorded initially (size) or overwritten with the delta type
1556  *      (type) when check_object() decided to reuse the delta.
1557  *
1558  *   3. Resetting our delta depth, as we are now a base object.
1559  */
1560 static void drop_reused_delta(struct object_entry *entry)
1561 {
1562         struct object_entry **p = &entry->delta->delta_child;
1563         struct object_info oi = OBJECT_INFO_INIT;
1564
1565         while (*p) {
1566                 if (*p == entry)
1567                         *p = (*p)->delta_sibling;
1568                 else
1569                         p = &(*p)->delta_sibling;
1570         }
1571         entry->delta = NULL;
1572         entry->depth = 0;
1573
1574         oi.sizep = &entry->size;
1575         oi.typep = &entry->type;
1576         if (packed_object_info(entry->in_pack, entry->in_pack_offset, &oi) < 0) {
1577                 /*
1578                  * We failed to get the info from this pack for some reason;
1579                  * fall back to sha1_object_info, which may find another copy.
1580                  * And if that fails, the error will be recorded in entry->type
1581                  * and dealt with in prepare_pack().
1582                  */
1583                 entry->type = oid_object_info(&entry->idx.oid, &entry->size);
1584         }
1585 }
1586
1587 /*
1588  * Follow the chain of deltas from this entry onward, throwing away any links
1589  * that cause us to hit a cycle (as determined by the DFS state flags in
1590  * the entries).
1591  *
1592  * We also detect too-long reused chains that would violate our --depth
1593  * limit.
1594  */
1595 static void break_delta_chains(struct object_entry *entry)
1596 {
1597         /*
1598          * The actual depth of each object we will write is stored as an int,
1599          * as it cannot exceed our int "depth" limit. But before we break
1600          * changes based no that limit, we may potentially go as deep as the
1601          * number of objects, which is elsewhere bounded to a uint32_t.
1602          */
1603         uint32_t total_depth;
1604         struct object_entry *cur, *next;
1605
1606         for (cur = entry, total_depth = 0;
1607              cur;
1608              cur = cur->delta, total_depth++) {
1609                 if (cur->dfs_state == DFS_DONE) {
1610                         /*
1611                          * We've already seen this object and know it isn't
1612                          * part of a cycle. We do need to append its depth
1613                          * to our count.
1614                          */
1615                         total_depth += cur->depth;
1616                         break;
1617                 }
1618
1619                 /*
1620                  * We break cycles before looping, so an ACTIVE state (or any
1621                  * other cruft which made its way into the state variable)
1622                  * is a bug.
1623                  */
1624                 if (cur->dfs_state != DFS_NONE)
1625                         die("BUG: confusing delta dfs state in first pass: %d",
1626                             cur->dfs_state);
1627
1628                 /*
1629                  * Now we know this is the first time we've seen the object. If
1630                  * it's not a delta, we're done traversing, but we'll mark it
1631                  * done to save time on future traversals.
1632                  */
1633                 if (!cur->delta) {
1634                         cur->dfs_state = DFS_DONE;
1635                         break;
1636                 }
1637
1638                 /*
1639                  * Mark ourselves as active and see if the next step causes
1640                  * us to cycle to another active object. It's important to do
1641                  * this _before_ we loop, because it impacts where we make the
1642                  * cut, and thus how our total_depth counter works.
1643                  * E.g., We may see a partial loop like:
1644                  *
1645                  *   A -> B -> C -> D -> B
1646                  *
1647                  * Cutting B->C breaks the cycle. But now the depth of A is
1648                  * only 1, and our total_depth counter is at 3. The size of the
1649                  * error is always one less than the size of the cycle we
1650                  * broke. Commits C and D were "lost" from A's chain.
1651                  *
1652                  * If we instead cut D->B, then the depth of A is correct at 3.
1653                  * We keep all commits in the chain that we examined.
1654                  */
1655                 cur->dfs_state = DFS_ACTIVE;
1656                 if (cur->delta->dfs_state == DFS_ACTIVE) {
1657                         drop_reused_delta(cur);
1658                         cur->dfs_state = DFS_DONE;
1659                         break;
1660                 }
1661         }
1662
1663         /*
1664          * And now that we've gone all the way to the bottom of the chain, we
1665          * need to clear the active flags and set the depth fields as
1666          * appropriate. Unlike the loop above, which can quit when it drops a
1667          * delta, we need to keep going to look for more depth cuts. So we need
1668          * an extra "next" pointer to keep going after we reset cur->delta.
1669          */
1670         for (cur = entry; cur; cur = next) {
1671                 next = cur->delta;
1672
1673                 /*
1674                  * We should have a chain of zero or more ACTIVE states down to
1675                  * a final DONE. We can quit after the DONE, because either it
1676                  * has no bases, or we've already handled them in a previous
1677                  * call.
1678                  */
1679                 if (cur->dfs_state == DFS_DONE)
1680                         break;
1681                 else if (cur->dfs_state != DFS_ACTIVE)
1682                         die("BUG: confusing delta dfs state in second pass: %d",
1683                             cur->dfs_state);
1684
1685                 /*
1686                  * If the total_depth is more than depth, then we need to snip
1687                  * the chain into two or more smaller chains that don't exceed
1688                  * the maximum depth. Most of the resulting chains will contain
1689                  * (depth + 1) entries (i.e., depth deltas plus one base), and
1690                  * the last chain (i.e., the one containing entry) will contain
1691                  * whatever entries are left over, namely
1692                  * (total_depth % (depth + 1)) of them.
1693                  *
1694                  * Since we are iterating towards decreasing depth, we need to
1695                  * decrement total_depth as we go, and we need to write to the
1696                  * entry what its final depth will be after all of the
1697                  * snipping. Since we're snipping into chains of length (depth
1698                  * + 1) entries, the final depth of an entry will be its
1699                  * original depth modulo (depth + 1). Any time we encounter an
1700                  * entry whose final depth is supposed to be zero, we snip it
1701                  * from its delta base, thereby making it so.
1702                  */
1703                 cur->depth = (total_depth--) % (depth + 1);
1704                 if (!cur->depth)
1705                         drop_reused_delta(cur);
1706
1707                 cur->dfs_state = DFS_DONE;
1708         }
1709 }
1710
1711 static void get_object_details(void)
1712 {
1713         uint32_t i;
1714         struct object_entry **sorted_by_offset;
1715
1716         sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
1717         for (i = 0; i < to_pack.nr_objects; i++)
1718                 sorted_by_offset[i] = to_pack.objects + i;
1719         QSORT(sorted_by_offset, to_pack.nr_objects, pack_offset_sort);
1720
1721         for (i = 0; i < to_pack.nr_objects; i++) {
1722                 struct object_entry *entry = sorted_by_offset[i];
1723                 check_object(entry);
1724                 if (big_file_threshold < entry->size)
1725                         entry->no_try_delta = 1;
1726         }
1727
1728         /*
1729          * This must happen in a second pass, since we rely on the delta
1730          * information for the whole list being completed.
1731          */
1732         for (i = 0; i < to_pack.nr_objects; i++)
1733                 break_delta_chains(&to_pack.objects[i]);
1734
1735         free(sorted_by_offset);
1736 }
1737
1738 /*
1739  * We search for deltas in a list sorted by type, by filename hash, and then
1740  * by size, so that we see progressively smaller and smaller files.
1741  * That's because we prefer deltas to be from the bigger file
1742  * to the smaller -- deletes are potentially cheaper, but perhaps
1743  * more importantly, the bigger file is likely the more recent
1744  * one.  The deepest deltas are therefore the oldest objects which are
1745  * less susceptible to be accessed often.
1746  */
1747 static int type_size_sort(const void *_a, const void *_b)
1748 {
1749         const struct object_entry *a = *(struct object_entry **)_a;
1750         const struct object_entry *b = *(struct object_entry **)_b;
1751
1752         if (a->type > b->type)
1753                 return -1;
1754         if (a->type < b->type)
1755                 return 1;
1756         if (a->hash > b->hash)
1757                 return -1;
1758         if (a->hash < b->hash)
1759                 return 1;
1760         if (a->preferred_base > b->preferred_base)
1761                 return -1;
1762         if (a->preferred_base < b->preferred_base)
1763                 return 1;
1764         if (a->size > b->size)
1765                 return -1;
1766         if (a->size < b->size)
1767                 return 1;
1768         return a < b ? -1 : (a > b);  /* newest first */
1769 }
1770
1771 struct unpacked {
1772         struct object_entry *entry;
1773         void *data;
1774         struct delta_index *index;
1775         unsigned depth;
1776 };
1777
1778 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1779                            unsigned long delta_size)
1780 {
1781         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1782                 return 0;
1783
1784         if (delta_size < cache_max_small_delta_size)
1785                 return 1;
1786
1787         /* cache delta, if objects are large enough compared to delta size */
1788         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1789                 return 1;
1790
1791         return 0;
1792 }
1793
1794 #ifndef NO_PTHREADS
1795
1796 static pthread_mutex_t read_mutex;
1797 #define read_lock()             pthread_mutex_lock(&read_mutex)
1798 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1799
1800 static pthread_mutex_t cache_mutex;
1801 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1802 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1803
1804 static pthread_mutex_t progress_mutex;
1805 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1806 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1807
1808 #else
1809
1810 #define read_lock()             (void)0
1811 #define read_unlock()           (void)0
1812 #define cache_lock()            (void)0
1813 #define cache_unlock()          (void)0
1814 #define progress_lock()         (void)0
1815 #define progress_unlock()       (void)0
1816
1817 #endif
1818
1819 static int try_delta(struct unpacked *trg, struct unpacked *src,
1820                      unsigned max_depth, unsigned long *mem_usage)
1821 {
1822         struct object_entry *trg_entry = trg->entry;
1823         struct object_entry *src_entry = src->entry;
1824         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1825         unsigned ref_depth;
1826         enum object_type type;
1827         void *delta_buf;
1828
1829         /* Don't bother doing diffs between different types */
1830         if (trg_entry->type != src_entry->type)
1831                 return -1;
1832
1833         /*
1834          * We do not bother to try a delta that we discarded on an
1835          * earlier try, but only when reusing delta data.  Note that
1836          * src_entry that is marked as the preferred_base should always
1837          * be considered, as even if we produce a suboptimal delta against
1838          * it, we will still save the transfer cost, as we already know
1839          * the other side has it and we won't send src_entry at all.
1840          */
1841         if (reuse_delta && trg_entry->in_pack &&
1842             trg_entry->in_pack == src_entry->in_pack &&
1843             !src_entry->preferred_base &&
1844             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1845             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1846                 return 0;
1847
1848         /* Let's not bust the allowed depth. */
1849         if (src->depth >= max_depth)
1850                 return 0;
1851
1852         /* Now some size filtering heuristics. */
1853         trg_size = trg_entry->size;
1854         if (!trg_entry->delta) {
1855                 max_size = trg_size/2 - the_hash_algo->rawsz;
1856                 ref_depth = 1;
1857         } else {
1858                 max_size = trg_entry->delta_size;
1859                 ref_depth = trg->depth;
1860         }
1861         max_size = (uint64_t)max_size * (max_depth - src->depth) /
1862                                                 (max_depth - ref_depth + 1);
1863         if (max_size == 0)
1864                 return 0;
1865         src_size = src_entry->size;
1866         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1867         if (sizediff >= max_size)
1868                 return 0;
1869         if (trg_size < src_size / 32)
1870                 return 0;
1871
1872         /* Load data if not already done */
1873         if (!trg->data) {
1874                 read_lock();
1875                 trg->data = read_object_file(&trg_entry->idx.oid, &type, &sz);
1876                 read_unlock();
1877                 if (!trg->data)
1878                         die("object %s cannot be read",
1879                             oid_to_hex(&trg_entry->idx.oid));
1880                 if (sz != trg_size)
1881                         die("object %s inconsistent object length (%lu vs %lu)",
1882                             oid_to_hex(&trg_entry->idx.oid), sz,
1883                             trg_size);
1884                 *mem_usage += sz;
1885         }
1886         if (!src->data) {
1887                 read_lock();
1888                 src->data = read_object_file(&src_entry->idx.oid, &type, &sz);
1889                 read_unlock();
1890                 if (!src->data) {
1891                         if (src_entry->preferred_base) {
1892                                 static int warned = 0;
1893                                 if (!warned++)
1894                                         warning("object %s cannot be read",
1895                                                 oid_to_hex(&src_entry->idx.oid));
1896                                 /*
1897                                  * Those objects are not included in the
1898                                  * resulting pack.  Be resilient and ignore
1899                                  * them if they can't be read, in case the
1900                                  * pack could be created nevertheless.
1901                                  */
1902                                 return 0;
1903                         }
1904                         die("object %s cannot be read",
1905                             oid_to_hex(&src_entry->idx.oid));
1906                 }
1907                 if (sz != src_size)
1908                         die("object %s inconsistent object length (%lu vs %lu)",
1909                             oid_to_hex(&src_entry->idx.oid), sz,
1910                             src_size);
1911                 *mem_usage += sz;
1912         }
1913         if (!src->index) {
1914                 src->index = create_delta_index(src->data, src_size);
1915                 if (!src->index) {
1916                         static int warned = 0;
1917                         if (!warned++)
1918                                 warning("suboptimal pack - out of memory");
1919                         return 0;
1920                 }
1921                 *mem_usage += sizeof_delta_index(src->index);
1922         }
1923
1924         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1925         if (!delta_buf)
1926                 return 0;
1927
1928         if (trg_entry->delta) {
1929                 /* Prefer only shallower same-sized deltas. */
1930                 if (delta_size == trg_entry->delta_size &&
1931                     src->depth + 1 >= trg->depth) {
1932                         free(delta_buf);
1933                         return 0;
1934                 }
1935         }
1936
1937         /*
1938          * Handle memory allocation outside of the cache
1939          * accounting lock.  Compiler will optimize the strangeness
1940          * away when NO_PTHREADS is defined.
1941          */
1942         free(trg_entry->delta_data);
1943         cache_lock();
1944         if (trg_entry->delta_data) {
1945                 delta_cache_size -= trg_entry->delta_size;
1946                 trg_entry->delta_data = NULL;
1947         }
1948         if (delta_cacheable(src_size, trg_size, delta_size)) {
1949                 delta_cache_size += delta_size;
1950                 cache_unlock();
1951                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1952         } else {
1953                 cache_unlock();
1954                 free(delta_buf);
1955         }
1956
1957         trg_entry->delta = src_entry;
1958         trg_entry->delta_size = delta_size;
1959         trg->depth = src->depth + 1;
1960
1961         return 1;
1962 }
1963
1964 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1965 {
1966         struct object_entry *child = me->delta_child;
1967         unsigned int m = n;
1968         while (child) {
1969                 unsigned int c = check_delta_limit(child, n + 1);
1970                 if (m < c)
1971                         m = c;
1972                 child = child->delta_sibling;
1973         }
1974         return m;
1975 }
1976
1977 static unsigned long free_unpacked(struct unpacked *n)
1978 {
1979         unsigned long freed_mem = sizeof_delta_index(n->index);
1980         free_delta_index(n->index);
1981         n->index = NULL;
1982         if (n->data) {
1983                 freed_mem += n->entry->size;
1984                 FREE_AND_NULL(n->data);
1985         }
1986         n->entry = NULL;
1987         n->depth = 0;
1988         return freed_mem;
1989 }
1990
1991 static void find_deltas(struct object_entry **list, unsigned *list_size,
1992                         int window, int depth, unsigned *processed)
1993 {
1994         uint32_t i, idx = 0, count = 0;
1995         struct unpacked *array;
1996         unsigned long mem_usage = 0;
1997
1998         array = xcalloc(window, sizeof(struct unpacked));
1999
2000         for (;;) {
2001                 struct object_entry *entry;
2002                 struct unpacked *n = array + idx;
2003                 int j, max_depth, best_base = -1;
2004
2005                 progress_lock();
2006                 if (!*list_size) {
2007                         progress_unlock();
2008                         break;
2009                 }
2010                 entry = *list++;
2011                 (*list_size)--;
2012                 if (!entry->preferred_base) {
2013                         (*processed)++;
2014                         display_progress(progress_state, *processed);
2015                 }
2016                 progress_unlock();
2017
2018                 mem_usage -= free_unpacked(n);
2019                 n->entry = entry;
2020
2021                 while (window_memory_limit &&
2022                        mem_usage > window_memory_limit &&
2023                        count > 1) {
2024                         uint32_t tail = (idx + window - count) % window;
2025                         mem_usage -= free_unpacked(array + tail);
2026                         count--;
2027                 }
2028
2029                 /* We do not compute delta to *create* objects we are not
2030                  * going to pack.
2031                  */
2032                 if (entry->preferred_base)
2033                         goto next;
2034
2035                 /*
2036                  * If the current object is at pack edge, take the depth the
2037                  * objects that depend on the current object into account
2038                  * otherwise they would become too deep.
2039                  */
2040                 max_depth = depth;
2041                 if (entry->delta_child) {
2042                         max_depth -= check_delta_limit(entry, 0);
2043                         if (max_depth <= 0)
2044                                 goto next;
2045                 }
2046
2047                 j = window;
2048                 while (--j > 0) {
2049                         int ret;
2050                         uint32_t other_idx = idx + j;
2051                         struct unpacked *m;
2052                         if (other_idx >= window)
2053                                 other_idx -= window;
2054                         m = array + other_idx;
2055                         if (!m->entry)
2056                                 break;
2057                         ret = try_delta(n, m, max_depth, &mem_usage);
2058                         if (ret < 0)
2059                                 break;
2060                         else if (ret > 0)
2061                                 best_base = other_idx;
2062                 }
2063
2064                 /*
2065                  * If we decided to cache the delta data, then it is best
2066                  * to compress it right away.  First because we have to do
2067                  * it anyway, and doing it here while we're threaded will
2068                  * save a lot of time in the non threaded write phase,
2069                  * as well as allow for caching more deltas within
2070                  * the same cache size limit.
2071                  * ...
2072                  * But only if not writing to stdout, since in that case
2073                  * the network is most likely throttling writes anyway,
2074                  * and therefore it is best to go to the write phase ASAP
2075                  * instead, as we can afford spending more time compressing
2076                  * between writes at that moment.
2077                  */
2078                 if (entry->delta_data && !pack_to_stdout) {
2079                         entry->z_delta_size = do_compress(&entry->delta_data,
2080                                                           entry->delta_size);
2081                         cache_lock();
2082                         delta_cache_size -= entry->delta_size;
2083                         delta_cache_size += entry->z_delta_size;
2084                         cache_unlock();
2085                 }
2086
2087                 /* if we made n a delta, and if n is already at max
2088                  * depth, leaving it in the window is pointless.  we
2089                  * should evict it first.
2090                  */
2091                 if (entry->delta && max_depth <= n->depth)
2092                         continue;
2093
2094                 /*
2095                  * Move the best delta base up in the window, after the
2096                  * currently deltified object, to keep it longer.  It will
2097                  * be the first base object to be attempted next.
2098                  */
2099                 if (entry->delta) {
2100                         struct unpacked swap = array[best_base];
2101                         int dist = (window + idx - best_base) % window;
2102                         int dst = best_base;
2103                         while (dist--) {
2104                                 int src = (dst + 1) % window;
2105                                 array[dst] = array[src];
2106                                 dst = src;
2107                         }
2108                         array[dst] = swap;
2109                 }
2110
2111                 next:
2112                 idx++;
2113                 if (count + 1 < window)
2114                         count++;
2115                 if (idx >= window)
2116                         idx = 0;
2117         }
2118
2119         for (i = 0; i < window; ++i) {
2120                 free_delta_index(array[i].index);
2121                 free(array[i].data);
2122         }
2123         free(array);
2124 }
2125
2126 #ifndef NO_PTHREADS
2127
2128 static void try_to_free_from_threads(size_t size)
2129 {
2130         read_lock();
2131         release_pack_memory(size);
2132         read_unlock();
2133 }
2134
2135 static try_to_free_t old_try_to_free_routine;
2136
2137 /*
2138  * The main thread waits on the condition that (at least) one of the workers
2139  * has stopped working (which is indicated in the .working member of
2140  * struct thread_params).
2141  * When a work thread has completed its work, it sets .working to 0 and
2142  * signals the main thread and waits on the condition that .data_ready
2143  * becomes 1.
2144  */
2145
2146 struct thread_params {
2147         pthread_t thread;
2148         struct object_entry **list;
2149         unsigned list_size;
2150         unsigned remaining;
2151         int window;
2152         int depth;
2153         int working;
2154         int data_ready;
2155         pthread_mutex_t mutex;
2156         pthread_cond_t cond;
2157         unsigned *processed;
2158 };
2159
2160 static pthread_cond_t progress_cond;
2161
2162 /*
2163  * Mutex and conditional variable can't be statically-initialized on Windows.
2164  */
2165 static void init_threaded_search(void)
2166 {
2167         init_recursive_mutex(&read_mutex);
2168         pthread_mutex_init(&cache_mutex, NULL);
2169         pthread_mutex_init(&progress_mutex, NULL);
2170         pthread_cond_init(&progress_cond, NULL);
2171         old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
2172 }
2173
2174 static void cleanup_threaded_search(void)
2175 {
2176         set_try_to_free_routine(old_try_to_free_routine);
2177         pthread_cond_destroy(&progress_cond);
2178         pthread_mutex_destroy(&read_mutex);
2179         pthread_mutex_destroy(&cache_mutex);
2180         pthread_mutex_destroy(&progress_mutex);
2181 }
2182
2183 static void *threaded_find_deltas(void *arg)
2184 {
2185         struct thread_params *me = arg;
2186
2187         progress_lock();
2188         while (me->remaining) {
2189                 progress_unlock();
2190
2191                 find_deltas(me->list, &me->remaining,
2192                             me->window, me->depth, me->processed);
2193
2194                 progress_lock();
2195                 me->working = 0;
2196                 pthread_cond_signal(&progress_cond);
2197                 progress_unlock();
2198
2199                 /*
2200                  * We must not set ->data_ready before we wait on the
2201                  * condition because the main thread may have set it to 1
2202                  * before we get here. In order to be sure that new
2203                  * work is available if we see 1 in ->data_ready, it
2204                  * was initialized to 0 before this thread was spawned
2205                  * and we reset it to 0 right away.
2206                  */
2207                 pthread_mutex_lock(&me->mutex);
2208                 while (!me->data_ready)
2209                         pthread_cond_wait(&me->cond, &me->mutex);
2210                 me->data_ready = 0;
2211                 pthread_mutex_unlock(&me->mutex);
2212
2213                 progress_lock();
2214         }
2215         progress_unlock();
2216         /* leave ->working 1 so that this doesn't get more work assigned */
2217         return NULL;
2218 }
2219
2220 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
2221                            int window, int depth, unsigned *processed)
2222 {
2223         struct thread_params *p;
2224         int i, ret, active_threads = 0;
2225
2226         init_threaded_search();
2227
2228         if (delta_search_threads <= 1) {
2229                 find_deltas(list, &list_size, window, depth, processed);
2230                 cleanup_threaded_search();
2231                 return;
2232         }
2233         if (progress > pack_to_stdout)
2234                 fprintf(stderr, "Delta compression using up to %d threads.\n",
2235                                 delta_search_threads);
2236         p = xcalloc(delta_search_threads, sizeof(*p));
2237
2238         /* Partition the work amongst work threads. */
2239         for (i = 0; i < delta_search_threads; i++) {
2240                 unsigned sub_size = list_size / (delta_search_threads - i);
2241
2242                 /* don't use too small segments or no deltas will be found */
2243                 if (sub_size < 2*window && i+1 < delta_search_threads)
2244                         sub_size = 0;
2245
2246                 p[i].window = window;
2247                 p[i].depth = depth;
2248                 p[i].processed = processed;
2249                 p[i].working = 1;
2250                 p[i].data_ready = 0;
2251
2252                 /* try to split chunks on "path" boundaries */
2253                 while (sub_size && sub_size < list_size &&
2254                        list[sub_size]->hash &&
2255                        list[sub_size]->hash == list[sub_size-1]->hash)
2256                         sub_size++;
2257
2258                 p[i].list = list;
2259                 p[i].list_size = sub_size;
2260                 p[i].remaining = sub_size;
2261
2262                 list += sub_size;
2263                 list_size -= sub_size;
2264         }
2265
2266         /* Start work threads. */
2267         for (i = 0; i < delta_search_threads; i++) {
2268                 if (!p[i].list_size)
2269                         continue;
2270                 pthread_mutex_init(&p[i].mutex, NULL);
2271                 pthread_cond_init(&p[i].cond, NULL);
2272                 ret = pthread_create(&p[i].thread, NULL,
2273                                      threaded_find_deltas, &p[i]);
2274                 if (ret)
2275                         die("unable to create thread: %s", strerror(ret));
2276                 active_threads++;
2277         }
2278
2279         /*
2280          * Now let's wait for work completion.  Each time a thread is done
2281          * with its work, we steal half of the remaining work from the
2282          * thread with the largest number of unprocessed objects and give
2283          * it to that newly idle thread.  This ensure good load balancing
2284          * until the remaining object list segments are simply too short
2285          * to be worth splitting anymore.
2286          */
2287         while (active_threads) {
2288                 struct thread_params *target = NULL;
2289                 struct thread_params *victim = NULL;
2290                 unsigned sub_size = 0;
2291
2292                 progress_lock();
2293                 for (;;) {
2294                         for (i = 0; !target && i < delta_search_threads; i++)
2295                                 if (!p[i].working)
2296                                         target = &p[i];
2297                         if (target)
2298                                 break;
2299                         pthread_cond_wait(&progress_cond, &progress_mutex);
2300                 }
2301
2302                 for (i = 0; i < delta_search_threads; i++)
2303                         if (p[i].remaining > 2*window &&
2304                             (!victim || victim->remaining < p[i].remaining))
2305                                 victim = &p[i];
2306                 if (victim) {
2307                         sub_size = victim->remaining / 2;
2308                         list = victim->list + victim->list_size - sub_size;
2309                         while (sub_size && list[0]->hash &&
2310                                list[0]->hash == list[-1]->hash) {
2311                                 list++;
2312                                 sub_size--;
2313                         }
2314                         if (!sub_size) {
2315                                 /*
2316                                  * It is possible for some "paths" to have
2317                                  * so many objects that no hash boundary
2318                                  * might be found.  Let's just steal the
2319                                  * exact half in that case.
2320                                  */
2321                                 sub_size = victim->remaining / 2;
2322                                 list -= sub_size;
2323                         }
2324                         target->list = list;
2325                         victim->list_size -= sub_size;
2326                         victim->remaining -= sub_size;
2327                 }
2328                 target->list_size = sub_size;
2329                 target->remaining = sub_size;
2330                 target->working = 1;
2331                 progress_unlock();
2332
2333                 pthread_mutex_lock(&target->mutex);
2334                 target->data_ready = 1;
2335                 pthread_cond_signal(&target->cond);
2336                 pthread_mutex_unlock(&target->mutex);
2337
2338                 if (!sub_size) {
2339                         pthread_join(target->thread, NULL);
2340                         pthread_cond_destroy(&target->cond);
2341                         pthread_mutex_destroy(&target->mutex);
2342                         active_threads--;
2343                 }
2344         }
2345         cleanup_threaded_search();
2346         free(p);
2347 }
2348
2349 #else
2350 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
2351 #endif
2352
2353 static void add_tag_chain(const struct object_id *oid)
2354 {
2355         struct tag *tag;
2356
2357         /*
2358          * We catch duplicates already in add_object_entry(), but we'd
2359          * prefer to do this extra check to avoid having to parse the
2360          * tag at all if we already know that it's being packed (e.g., if
2361          * it was included via bitmaps, we would not have parsed it
2362          * previously).
2363          */
2364         if (packlist_find(&to_pack, oid->hash, NULL))
2365                 return;
2366
2367         tag = lookup_tag(oid);
2368         while (1) {
2369                 if (!tag || parse_tag(tag) || !tag->tagged)
2370                         die("unable to pack objects reachable from tag %s",
2371                             oid_to_hex(oid));
2372
2373                 add_object_entry(&tag->object.oid, OBJ_TAG, NULL, 0);
2374
2375                 if (tag->tagged->type != OBJ_TAG)
2376                         return;
2377
2378                 tag = (struct tag *)tag->tagged;
2379         }
2380 }
2381
2382 static int add_ref_tag(const char *path, const struct object_id *oid, int flag, void *cb_data)
2383 {
2384         struct object_id peeled;
2385
2386         if (starts_with(path, "refs/tags/") && /* is a tag? */
2387             !peel_ref(path, &peeled)    && /* peelable? */
2388             packlist_find(&to_pack, peeled.hash, NULL))      /* object packed? */
2389                 add_tag_chain(oid);
2390         return 0;
2391 }
2392
2393 static void prepare_pack(int window, int depth)
2394 {
2395         struct object_entry **delta_list;
2396         uint32_t i, nr_deltas;
2397         unsigned n;
2398
2399         get_object_details();
2400
2401         /*
2402          * If we're locally repacking then we need to be doubly careful
2403          * from now on in order to make sure no stealth corruption gets
2404          * propagated to the new pack.  Clients receiving streamed packs
2405          * should validate everything they get anyway so no need to incur
2406          * the additional cost here in that case.
2407          */
2408         if (!pack_to_stdout)
2409                 do_check_packed_object_crc = 1;
2410
2411         if (!to_pack.nr_objects || !window || !depth)
2412                 return;
2413
2414         ALLOC_ARRAY(delta_list, to_pack.nr_objects);
2415         nr_deltas = n = 0;
2416
2417         for (i = 0; i < to_pack.nr_objects; i++) {
2418                 struct object_entry *entry = to_pack.objects + i;
2419
2420                 if (entry->delta)
2421                         /* This happens if we decided to reuse existing
2422                          * delta from a pack.  "reuse_delta &&" is implied.
2423                          */
2424                         continue;
2425
2426                 if (entry->size < 50)
2427                         continue;
2428
2429                 if (entry->no_try_delta)
2430                         continue;
2431
2432                 if (!entry->preferred_base) {
2433                         nr_deltas++;
2434                         if (entry->type < 0)
2435                                 die("unable to get type of object %s",
2436                                     oid_to_hex(&entry->idx.oid));
2437                 } else {
2438                         if (entry->type < 0) {
2439                                 /*
2440                                  * This object is not found, but we
2441                                  * don't have to include it anyway.
2442                                  */
2443                                 continue;
2444                         }
2445                 }
2446
2447                 delta_list[n++] = entry;
2448         }
2449
2450         if (nr_deltas && n > 1) {
2451                 unsigned nr_done = 0;
2452                 if (progress)
2453                         progress_state = start_progress(_("Compressing objects"),
2454                                                         nr_deltas);
2455                 QSORT(delta_list, n, type_size_sort);
2456                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2457                 stop_progress(&progress_state);
2458                 if (nr_done != nr_deltas)
2459                         die("inconsistency with delta count");
2460         }
2461         free(delta_list);
2462 }
2463
2464 static int git_pack_config(const char *k, const char *v, void *cb)
2465 {
2466         if (!strcmp(k, "pack.window")) {
2467                 window = git_config_int(k, v);
2468                 return 0;
2469         }
2470         if (!strcmp(k, "pack.windowmemory")) {
2471                 window_memory_limit = git_config_ulong(k, v);
2472                 return 0;
2473         }
2474         if (!strcmp(k, "pack.depth")) {
2475                 depth = git_config_int(k, v);
2476                 return 0;
2477         }
2478         if (!strcmp(k, "pack.deltacachesize")) {
2479                 max_delta_cache_size = git_config_int(k, v);
2480                 return 0;
2481         }
2482         if (!strcmp(k, "pack.deltacachelimit")) {
2483                 cache_max_small_delta_size = git_config_int(k, v);
2484                 return 0;
2485         }
2486         if (!strcmp(k, "pack.writebitmaphashcache")) {
2487                 if (git_config_bool(k, v))
2488                         write_bitmap_options |= BITMAP_OPT_HASH_CACHE;
2489                 else
2490                         write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
2491         }
2492         if (!strcmp(k, "pack.usebitmaps")) {
2493                 use_bitmap_index_default = git_config_bool(k, v);
2494                 return 0;
2495         }
2496         if (!strcmp(k, "pack.threads")) {
2497                 delta_search_threads = git_config_int(k, v);
2498                 if (delta_search_threads < 0)
2499                         die("invalid number of threads specified (%d)",
2500                             delta_search_threads);
2501 #ifdef NO_PTHREADS
2502                 if (delta_search_threads != 1) {
2503                         warning("no threads support, ignoring %s", k);
2504                         delta_search_threads = 0;
2505                 }
2506 #endif
2507                 return 0;
2508         }
2509         if (!strcmp(k, "pack.indexversion")) {
2510                 pack_idx_opts.version = git_config_int(k, v);
2511                 if (pack_idx_opts.version > 2)
2512                         die("bad pack.indexversion=%"PRIu32,
2513                             pack_idx_opts.version);
2514                 return 0;
2515         }
2516         return git_default_config(k, v, cb);
2517 }
2518
2519 static void read_object_list_from_stdin(void)
2520 {
2521         char line[GIT_MAX_HEXSZ + 1 + PATH_MAX + 2];
2522         struct object_id oid;
2523         const char *p;
2524
2525         for (;;) {
2526                 if (!fgets(line, sizeof(line), stdin)) {
2527                         if (feof(stdin))
2528                                 break;
2529                         if (!ferror(stdin))
2530                                 die("fgets returned NULL, not EOF, not error!");
2531                         if (errno != EINTR)
2532                                 die_errno("fgets");
2533                         clearerr(stdin);
2534                         continue;
2535                 }
2536                 if (line[0] == '-') {
2537                         if (get_oid_hex(line+1, &oid))
2538                                 die("expected edge object ID, got garbage:\n %s",
2539                                     line);
2540                         add_preferred_base(&oid);
2541                         continue;
2542                 }
2543                 if (parse_oid_hex(line, &oid, &p))
2544                         die("expected object ID, got garbage:\n %s", line);
2545
2546                 add_preferred_base_object(p + 1);
2547                 add_object_entry(&oid, 0, p + 1, 0);
2548         }
2549 }
2550
2551 /* Remember to update object flag allocation in object.h */
2552 #define OBJECT_ADDED (1u<<20)
2553
2554 static void show_commit(struct commit *commit, void *data)
2555 {
2556         add_object_entry(&commit->object.oid, OBJ_COMMIT, NULL, 0);
2557         commit->object.flags |= OBJECT_ADDED;
2558
2559         if (write_bitmap_index)
2560                 index_commit_for_bitmap(commit);
2561 }
2562
2563 static void show_object(struct object *obj, const char *name, void *data)
2564 {
2565         add_preferred_base_object(name);
2566         add_object_entry(&obj->oid, obj->type, name, 0);
2567         obj->flags |= OBJECT_ADDED;
2568 }
2569
2570 static void show_object__ma_allow_any(struct object *obj, const char *name, void *data)
2571 {
2572         assert(arg_missing_action == MA_ALLOW_ANY);
2573
2574         /*
2575          * Quietly ignore ALL missing objects.  This avoids problems with
2576          * staging them now and getting an odd error later.
2577          */
2578         if (!has_object_file(&obj->oid))
2579                 return;
2580
2581         show_object(obj, name, data);
2582 }
2583
2584 static void show_object__ma_allow_promisor(struct object *obj, const char *name, void *data)
2585 {
2586         assert(arg_missing_action == MA_ALLOW_PROMISOR);
2587
2588         /*
2589          * Quietly ignore EXPECTED missing objects.  This avoids problems with
2590          * staging them now and getting an odd error later.
2591          */
2592         if (!has_object_file(&obj->oid) && is_promisor_object(&obj->oid))
2593                 return;
2594
2595         show_object(obj, name, data);
2596 }
2597
2598 static int option_parse_missing_action(const struct option *opt,
2599                                        const char *arg, int unset)
2600 {
2601         assert(arg);
2602         assert(!unset);
2603
2604         if (!strcmp(arg, "error")) {
2605                 arg_missing_action = MA_ERROR;
2606                 fn_show_object = show_object;
2607                 return 0;
2608         }
2609
2610         if (!strcmp(arg, "allow-any")) {
2611                 arg_missing_action = MA_ALLOW_ANY;
2612                 fetch_if_missing = 0;
2613                 fn_show_object = show_object__ma_allow_any;
2614                 return 0;
2615         }
2616
2617         if (!strcmp(arg, "allow-promisor")) {
2618                 arg_missing_action = MA_ALLOW_PROMISOR;
2619                 fetch_if_missing = 0;
2620                 fn_show_object = show_object__ma_allow_promisor;
2621                 return 0;
2622         }
2623
2624         die(_("invalid value for --missing"));
2625         return 0;
2626 }
2627
2628 static void show_edge(struct commit *commit)
2629 {
2630         add_preferred_base(&commit->object.oid);
2631 }
2632
2633 struct in_pack_object {
2634         off_t offset;
2635         struct object *object;
2636 };
2637
2638 struct in_pack {
2639         unsigned int alloc;
2640         unsigned int nr;
2641         struct in_pack_object *array;
2642 };
2643
2644 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2645 {
2646         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->oid.hash, p);
2647         in_pack->array[in_pack->nr].object = object;
2648         in_pack->nr++;
2649 }
2650
2651 /*
2652  * Compare the objects in the offset order, in order to emulate the
2653  * "git rev-list --objects" output that produced the pack originally.
2654  */
2655 static int ofscmp(const void *a_, const void *b_)
2656 {
2657         struct in_pack_object *a = (struct in_pack_object *)a_;
2658         struct in_pack_object *b = (struct in_pack_object *)b_;
2659
2660         if (a->offset < b->offset)
2661                 return -1;
2662         else if (a->offset > b->offset)
2663                 return 1;
2664         else
2665                 return oidcmp(&a->object->oid, &b->object->oid);
2666 }
2667
2668 static void add_objects_in_unpacked_packs(struct rev_info *revs)
2669 {
2670         struct packed_git *p;
2671         struct in_pack in_pack;
2672         uint32_t i;
2673
2674         memset(&in_pack, 0, sizeof(in_pack));
2675
2676         for (p = get_packed_git(the_repository); p; p = p->next) {
2677                 struct object_id oid;
2678                 struct object *o;
2679
2680                 if (!p->pack_local || p->pack_keep)
2681                         continue;
2682                 if (open_pack_index(p))
2683                         die("cannot open pack index");
2684
2685                 ALLOC_GROW(in_pack.array,
2686                            in_pack.nr + p->num_objects,
2687                            in_pack.alloc);
2688
2689                 for (i = 0; i < p->num_objects; i++) {
2690                         nth_packed_object_oid(&oid, p, i);
2691                         o = lookup_unknown_object(oid.hash);
2692                         if (!(o->flags & OBJECT_ADDED))
2693                                 mark_in_pack_object(o, p, &in_pack);
2694                         o->flags |= OBJECT_ADDED;
2695                 }
2696         }
2697
2698         if (in_pack.nr) {
2699                 QSORT(in_pack.array, in_pack.nr, ofscmp);
2700                 for (i = 0; i < in_pack.nr; i++) {
2701                         struct object *o = in_pack.array[i].object;
2702                         add_object_entry(&o->oid, o->type, "", 0);
2703                 }
2704         }
2705         free(in_pack.array);
2706 }
2707
2708 static int add_loose_object(const struct object_id *oid, const char *path,
2709                             void *data)
2710 {
2711         enum object_type type = oid_object_info(oid, NULL);
2712
2713         if (type < 0) {
2714                 warning("loose object at %s could not be examined", path);
2715                 return 0;
2716         }
2717
2718         add_object_entry(oid, type, "", 0);
2719         return 0;
2720 }
2721
2722 /*
2723  * We actually don't even have to worry about reachability here.
2724  * add_object_entry will weed out duplicates, so we just add every
2725  * loose object we find.
2726  */
2727 static void add_unreachable_loose_objects(void)
2728 {
2729         for_each_loose_file_in_objdir(get_object_directory(),
2730                                       add_loose_object,
2731                                       NULL, NULL, NULL);
2732 }
2733
2734 static int has_sha1_pack_kept_or_nonlocal(const struct object_id *oid)
2735 {
2736         static struct packed_git *last_found = (void *)1;
2737         struct packed_git *p;
2738
2739         p = (last_found != (void *)1) ? last_found :
2740                                         get_packed_git(the_repository);
2741
2742         while (p) {
2743                 if ((!p->pack_local || p->pack_keep) &&
2744                         find_pack_entry_one(oid->hash, p)) {
2745                         last_found = p;
2746                         return 1;
2747                 }
2748                 if (p == last_found)
2749                         p = get_packed_git(the_repository);
2750                 else
2751                         p = p->next;
2752                 if (p == last_found)
2753                         p = p->next;
2754         }
2755         return 0;
2756 }
2757
2758 /*
2759  * Store a list of sha1s that are should not be discarded
2760  * because they are either written too recently, or are
2761  * reachable from another object that was.
2762  *
2763  * This is filled by get_object_list.
2764  */
2765 static struct oid_array recent_objects;
2766
2767 static int loosened_object_can_be_discarded(const struct object_id *oid,
2768                                             timestamp_t mtime)
2769 {
2770         if (!unpack_unreachable_expiration)
2771                 return 0;
2772         if (mtime > unpack_unreachable_expiration)
2773                 return 0;
2774         if (oid_array_lookup(&recent_objects, oid) >= 0)
2775                 return 0;
2776         return 1;
2777 }
2778
2779 static void loosen_unused_packed_objects(struct rev_info *revs)
2780 {
2781         struct packed_git *p;
2782         uint32_t i;
2783         struct object_id oid;
2784
2785         for (p = get_packed_git(the_repository); p; p = p->next) {
2786                 if (!p->pack_local || p->pack_keep)
2787                         continue;
2788
2789                 if (open_pack_index(p))
2790                         die("cannot open pack index");
2791
2792                 for (i = 0; i < p->num_objects; i++) {
2793                         nth_packed_object_oid(&oid, p, i);
2794                         if (!packlist_find(&to_pack, oid.hash, NULL) &&
2795                             !has_sha1_pack_kept_or_nonlocal(&oid) &&
2796                             !loosened_object_can_be_discarded(&oid, p->mtime))
2797                                 if (force_object_loose(&oid, p->mtime))
2798                                         die("unable to force loose object");
2799                 }
2800         }
2801 }
2802
2803 /*
2804  * This tracks any options which pack-reuse code expects to be on, or which a
2805  * reader of the pack might not understand, and which would therefore prevent
2806  * blind reuse of what we have on disk.
2807  */
2808 static int pack_options_allow_reuse(void)
2809 {
2810         return pack_to_stdout &&
2811                allow_ofs_delta &&
2812                !ignore_packed_keep &&
2813                (!local || !have_non_local_packs) &&
2814                !incremental;
2815 }
2816
2817 static int get_object_list_from_bitmap(struct rev_info *revs)
2818 {
2819         if (prepare_bitmap_walk(revs) < 0)
2820                 return -1;
2821
2822         if (pack_options_allow_reuse() &&
2823             !reuse_partial_packfile_from_bitmap(
2824                         &reuse_packfile,
2825                         &reuse_packfile_objects,
2826                         &reuse_packfile_offset)) {
2827                 assert(reuse_packfile_objects);
2828                 nr_result += reuse_packfile_objects;
2829                 display_progress(progress_state, nr_result);
2830         }
2831
2832         traverse_bitmap_commit_list(&add_object_entry_from_bitmap);
2833         return 0;
2834 }
2835
2836 static void record_recent_object(struct object *obj,
2837                                  const char *name,
2838                                  void *data)
2839 {
2840         oid_array_append(&recent_objects, &obj->oid);
2841 }
2842
2843 static void record_recent_commit(struct commit *commit, void *data)
2844 {
2845         oid_array_append(&recent_objects, &commit->object.oid);
2846 }
2847
2848 static void get_object_list(int ac, const char **av)
2849 {
2850         struct rev_info revs;
2851         char line[1000];
2852         int flags = 0;
2853
2854         init_revisions(&revs, NULL);
2855         save_commit_buffer = 0;
2856         setup_revisions(ac, av, &revs, NULL);
2857
2858         /* make sure shallows are read */
2859         is_repository_shallow();
2860
2861         while (fgets(line, sizeof(line), stdin) != NULL) {
2862                 int len = strlen(line);
2863                 if (len && line[len - 1] == '\n')
2864                         line[--len] = 0;
2865                 if (!len)
2866                         break;
2867                 if (*line == '-') {
2868                         if (!strcmp(line, "--not")) {
2869                                 flags ^= UNINTERESTING;
2870                                 write_bitmap_index = 0;
2871                                 continue;
2872                         }
2873                         if (starts_with(line, "--shallow ")) {
2874                                 struct object_id oid;
2875                                 if (get_oid_hex(line + 10, &oid))
2876                                         die("not an SHA-1 '%s'", line + 10);
2877                                 register_shallow(&oid);
2878                                 use_bitmap_index = 0;
2879                                 continue;
2880                         }
2881                         die("not a rev '%s'", line);
2882                 }
2883                 if (handle_revision_arg(line, &revs, flags, REVARG_CANNOT_BE_FILENAME))
2884                         die("bad revision '%s'", line);
2885         }
2886
2887         if (use_bitmap_index && !get_object_list_from_bitmap(&revs))
2888                 return;
2889
2890         if (prepare_revision_walk(&revs))
2891                 die("revision walk setup failed");
2892         mark_edges_uninteresting(&revs, show_edge);
2893
2894         if (!fn_show_object)
2895                 fn_show_object = show_object;
2896         traverse_commit_list_filtered(&filter_options, &revs,
2897                                       show_commit, fn_show_object, NULL,
2898                                       NULL);
2899
2900         if (unpack_unreachable_expiration) {
2901                 revs.ignore_missing_links = 1;
2902                 if (add_unseen_recent_objects_to_traversal(&revs,
2903                                 unpack_unreachable_expiration))
2904                         die("unable to add recent objects");
2905                 if (prepare_revision_walk(&revs))
2906                         die("revision walk setup failed");
2907                 traverse_commit_list(&revs, record_recent_commit,
2908                                      record_recent_object, NULL);
2909         }
2910
2911         if (keep_unreachable)
2912                 add_objects_in_unpacked_packs(&revs);
2913         if (pack_loose_unreachable)
2914                 add_unreachable_loose_objects();
2915         if (unpack_unreachable)
2916                 loosen_unused_packed_objects(&revs);
2917
2918         oid_array_clear(&recent_objects);
2919 }
2920
2921 static int option_parse_index_version(const struct option *opt,
2922                                       const char *arg, int unset)
2923 {
2924         char *c;
2925         const char *val = arg;
2926         pack_idx_opts.version = strtoul(val, &c, 10);
2927         if (pack_idx_opts.version > 2)
2928                 die(_("unsupported index version %s"), val);
2929         if (*c == ',' && c[1])
2930                 pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2931         if (*c || pack_idx_opts.off32_limit & 0x80000000)
2932                 die(_("bad index version '%s'"), val);
2933         return 0;
2934 }
2935
2936 static int option_parse_unpack_unreachable(const struct option *opt,
2937                                            const char *arg, int unset)
2938 {
2939         if (unset) {
2940                 unpack_unreachable = 0;
2941                 unpack_unreachable_expiration = 0;
2942         }
2943         else {
2944                 unpack_unreachable = 1;
2945                 if (arg)
2946                         unpack_unreachable_expiration = approxidate(arg);
2947         }
2948         return 0;
2949 }
2950
2951 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2952 {
2953         int use_internal_rev_list = 0;
2954         int thin = 0;
2955         int shallow = 0;
2956         int all_progress_implied = 0;
2957         struct argv_array rp = ARGV_ARRAY_INIT;
2958         int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
2959         int rev_list_index = 0;
2960         struct option pack_objects_options[] = {
2961                 OPT_SET_INT('q', "quiet", &progress,
2962                             N_("do not show progress meter"), 0),
2963                 OPT_SET_INT(0, "progress", &progress,
2964                             N_("show progress meter"), 1),
2965                 OPT_SET_INT(0, "all-progress", &progress,
2966                             N_("show progress meter during object writing phase"), 2),
2967                 OPT_BOOL(0, "all-progress-implied",
2968                          &all_progress_implied,
2969                          N_("similar to --all-progress when progress meter is shown")),
2970                 { OPTION_CALLBACK, 0, "index-version", NULL, N_("version[,offset]"),
2971                   N_("write the pack index file in the specified idx format version"),
2972                   0, option_parse_index_version },
2973                 OPT_MAGNITUDE(0, "max-pack-size", &pack_size_limit,
2974                               N_("maximum size of each output pack file")),
2975                 OPT_BOOL(0, "local", &local,
2976                          N_("ignore borrowed objects from alternate object store")),
2977                 OPT_BOOL(0, "incremental", &incremental,
2978                          N_("ignore packed objects")),
2979                 OPT_INTEGER(0, "window", &window,
2980                             N_("limit pack window by objects")),
2981                 OPT_MAGNITUDE(0, "window-memory", &window_memory_limit,
2982                               N_("limit pack window by memory in addition to object limit")),
2983                 OPT_INTEGER(0, "depth", &depth,
2984                             N_("maximum length of delta chain allowed in the resulting pack")),
2985                 OPT_BOOL(0, "reuse-delta", &reuse_delta,
2986                          N_("reuse existing deltas")),
2987                 OPT_BOOL(0, "reuse-object", &reuse_object,
2988                          N_("reuse existing objects")),
2989                 OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
2990                          N_("use OFS_DELTA objects")),
2991                 OPT_INTEGER(0, "threads", &delta_search_threads,
2992                             N_("use threads when searching for best delta matches")),
2993                 OPT_BOOL(0, "non-empty", &non_empty,
2994                          N_("do not create an empty pack output")),
2995                 OPT_BOOL(0, "revs", &use_internal_rev_list,
2996                          N_("read revision arguments from standard input")),
2997                 { OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
2998                   N_("limit the objects to those that are not yet packed"),
2999                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3000                 { OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
3001                   N_("include objects reachable from any reference"),
3002                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3003                 { OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
3004                   N_("include objects referred by reflog entries"),
3005                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3006                 { OPTION_SET_INT, 0, "indexed-objects", &rev_list_index, NULL,
3007                   N_("include objects referred to by the index"),
3008                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3009                 OPT_BOOL(0, "stdout", &pack_to_stdout,
3010                          N_("output pack to stdout")),
3011                 OPT_BOOL(0, "include-tag", &include_tag,
3012                          N_("include tag objects that refer to objects to be packed")),
3013                 OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
3014                          N_("keep unreachable objects")),
3015                 OPT_BOOL(0, "pack-loose-unreachable", &pack_loose_unreachable,
3016                          N_("pack loose unreachable objects")),
3017                 { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, N_("time"),
3018                   N_("unpack unreachable objects newer than <time>"),
3019                   PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
3020                 OPT_BOOL(0, "thin", &thin,
3021                          N_("create thin packs")),
3022                 OPT_BOOL(0, "shallow", &shallow,
3023                          N_("create packs suitable for shallow fetches")),
3024                 OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
3025                          N_("ignore packs that have companion .keep file")),
3026                 OPT_INTEGER(0, "compression", &pack_compression_level,
3027                             N_("pack compression level")),
3028                 OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
3029                             N_("do not hide commits by grafts"), 0),
3030                 OPT_BOOL(0, "use-bitmap-index", &use_bitmap_index,
3031                          N_("use a bitmap index if available to speed up counting objects")),
3032                 OPT_BOOL(0, "write-bitmap-index", &write_bitmap_index,
3033                          N_("write a bitmap index together with the pack index")),
3034                 OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
3035                 { OPTION_CALLBACK, 0, "missing", NULL, N_("action"),
3036                   N_("handling for missing objects"), PARSE_OPT_NONEG,
3037                   option_parse_missing_action },
3038                 OPT_BOOL(0, "exclude-promisor-objects", &exclude_promisor_objects,
3039                          N_("do not pack objects in promisor packfiles")),
3040                 OPT_END(),
3041         };
3042
3043         check_replace_refs = 0;
3044
3045         reset_pack_idx_option(&pack_idx_opts);
3046         git_config(git_pack_config, NULL);
3047
3048         progress = isatty(2);
3049         argc = parse_options(argc, argv, prefix, pack_objects_options,
3050                              pack_usage, 0);
3051
3052         if (argc) {
3053                 base_name = argv[0];
3054                 argc--;
3055         }
3056         if (pack_to_stdout != !base_name || argc)
3057                 usage_with_options(pack_usage, pack_objects_options);
3058
3059         argv_array_push(&rp, "pack-objects");
3060         if (thin) {
3061                 use_internal_rev_list = 1;
3062                 argv_array_push(&rp, shallow
3063                                 ? "--objects-edge-aggressive"
3064                                 : "--objects-edge");
3065         } else
3066                 argv_array_push(&rp, "--objects");
3067
3068         if (rev_list_all) {
3069                 use_internal_rev_list = 1;
3070                 argv_array_push(&rp, "--all");
3071         }
3072         if (rev_list_reflog) {
3073                 use_internal_rev_list = 1;
3074                 argv_array_push(&rp, "--reflog");
3075         }
3076         if (rev_list_index) {
3077                 use_internal_rev_list = 1;
3078                 argv_array_push(&rp, "--indexed-objects");
3079         }
3080         if (rev_list_unpacked) {
3081                 use_internal_rev_list = 1;
3082                 argv_array_push(&rp, "--unpacked");
3083         }
3084
3085         if (exclude_promisor_objects) {
3086                 use_internal_rev_list = 1;
3087                 fetch_if_missing = 0;
3088                 argv_array_push(&rp, "--exclude-promisor-objects");
3089         }
3090
3091         if (!reuse_object)
3092                 reuse_delta = 0;
3093         if (pack_compression_level == -1)
3094                 pack_compression_level = Z_DEFAULT_COMPRESSION;
3095         else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
3096                 die("bad pack compression level %d", pack_compression_level);
3097
3098         if (!delta_search_threads)      /* --threads=0 means autodetect */
3099                 delta_search_threads = online_cpus();
3100
3101 #ifdef NO_PTHREADS
3102         if (delta_search_threads != 1)
3103                 warning("no threads support, ignoring --threads");
3104 #endif
3105         if (!pack_to_stdout && !pack_size_limit)
3106                 pack_size_limit = pack_size_limit_cfg;
3107         if (pack_to_stdout && pack_size_limit)
3108                 die("--max-pack-size cannot be used to build a pack for transfer.");
3109         if (pack_size_limit && pack_size_limit < 1024*1024) {
3110                 warning("minimum pack size limit is 1 MiB");
3111                 pack_size_limit = 1024*1024;
3112         }
3113
3114         if (!pack_to_stdout && thin)
3115                 die("--thin cannot be used to build an indexable pack.");
3116
3117         if (keep_unreachable && unpack_unreachable)
3118                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
3119         if (!rev_list_all || !rev_list_reflog || !rev_list_index)
3120                 unpack_unreachable_expiration = 0;
3121
3122         if (filter_options.choice) {
3123                 if (!pack_to_stdout)
3124                         die("cannot use --filter without --stdout.");
3125                 use_bitmap_index = 0;
3126         }
3127
3128         /*
3129          * "soft" reasons not to use bitmaps - for on-disk repack by default we want
3130          *
3131          * - to produce good pack (with bitmap index not-yet-packed objects are
3132          *   packed in suboptimal order).
3133          *
3134          * - to use more robust pack-generation codepath (avoiding possible
3135          *   bugs in bitmap code and possible bitmap index corruption).
3136          */
3137         if (!pack_to_stdout)
3138                 use_bitmap_index_default = 0;
3139
3140         if (use_bitmap_index < 0)
3141                 use_bitmap_index = use_bitmap_index_default;
3142
3143         /* "hard" reasons not to use bitmaps; these just won't work at all */
3144         if (!use_internal_rev_list || (!pack_to_stdout && write_bitmap_index) || is_repository_shallow())
3145                 use_bitmap_index = 0;
3146
3147         if (pack_to_stdout || !rev_list_all)
3148                 write_bitmap_index = 0;
3149
3150         if (progress && all_progress_implied)
3151                 progress = 2;
3152
3153         if (ignore_packed_keep) {
3154                 struct packed_git *p;
3155                 for (p = get_packed_git(the_repository); p; p = p->next)
3156                         if (p->pack_local && p->pack_keep)
3157                                 break;
3158                 if (!p) /* no keep-able packs found */
3159                         ignore_packed_keep = 0;
3160         }
3161         if (local) {
3162                 /*
3163                  * unlike ignore_packed_keep above, we do not want to
3164                  * unset "local" based on looking at packs, as it
3165                  * also covers non-local objects
3166                  */
3167                 struct packed_git *p;
3168                 for (p = get_packed_git(the_repository); p; p = p->next) {
3169                         if (!p->pack_local) {
3170                                 have_non_local_packs = 1;
3171                                 break;
3172                         }
3173                 }
3174         }
3175
3176         if (progress)
3177                 progress_state = start_progress(_("Counting objects"), 0);
3178         if (!use_internal_rev_list)
3179                 read_object_list_from_stdin();
3180         else {
3181                 get_object_list(rp.argc, rp.argv);
3182                 argv_array_clear(&rp);
3183         }
3184         cleanup_preferred_base();
3185         if (include_tag && nr_result)
3186                 for_each_ref(add_ref_tag, NULL);
3187         stop_progress(&progress_state);
3188
3189         if (non_empty && !nr_result)
3190                 return 0;
3191         if (nr_result)
3192                 prepare_pack(window, depth);
3193         write_pack_file();
3194         if (progress)
3195                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
3196                         " reused %"PRIu32" (delta %"PRIu32")\n",
3197                         written, written_delta, reused, reused_delta);
3198         return 0;
3199 }