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
 268         if (!usable_delta) {
 269                 if (oe_type(entry) == OBJ_BLOB &&
 270                     entry->size > big_file_threshold &&
 271                     (st = open_istream(&entry->idx.oid, &type, &size, NULL)) != NULL)
 272                         buf = NULL;
 273                 else {
 274                         buf = read_object_file(&entry->idx.oid, &type, &size);
 275                         if (!buf)
 276                                 die(_("unable to read %s"),
 277                                     oid_to_hex(&entry->idx.oid));
 278                 }
 279                 /*
 280                  * make sure no cached delta data remains from a
 281                  * previous attempt before a pack split occurred.
 282                  */
 283                 FREE_AND_NULL(entry->delta_data);
 284                 entry->z_delta_size = 0;
 285         } else if (entry->delta_data) {
 286                 size = entry->delta_size;
 287                 buf = entry->delta_data;
 288                 entry->delta_data = NULL;
 289                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 290                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 291         } else {
 292                 buf = get_delta(entry);
 293                 size = entry->delta_size;
 294                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 295                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 296         }
 297
 298         if (st) /* large blob case, just assume we don't compress well */
 299                 datalen = size;
 300         else if (entry->z_delta_size)
 301                 datalen = entry->z_delta_size;
 302         else
 303                 datalen = do_compress(&buf, size);
 304
 305         /*
 306          * The object header is a byte of 'type' followed by zero or
 307          * more bytes of length.
 308          */
 309         hdrlen = encode_in_pack_object_header(header, sizeof(header),
 310                                               type, size);
 311
 312         if (type == OBJ_OFS_DELTA) {
 313                 /*
 314                  * Deltas with relative base contain an additional
 315                  * encoding of the relative offset for the delta
 316                  * base from this object's position in the pack.
 317                  */
 318                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 319                 unsigned pos = sizeof(dheader) - 1;
 320                 dheader[pos] = ofs & 127;
 321                 while (ofs >>= 7)
 322                         dheader[--pos] = 128 | (--ofs & 127);
 323                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 324                         if (st)
 325                                 close_istream(st);
 326                         free(buf);
 327                         return 0;
 328                 }
 329                 hashwrite(f, header, hdrlen);
 330                 hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 331                 hdrlen += sizeof(dheader) - pos;
 332         } else if (type == OBJ_REF_DELTA) {
 333                 /*
 334                  * Deltas with a base reference contain
 335                  * an additional 20 bytes for the base sha1.
 336                  */
 337                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 338                         if (st)
 339                                 close_istream(st);
 340                         free(buf);
 341                         return 0;
 342                 }
 343                 hashwrite(f, header, hdrlen);
 344                 hashwrite(f, entry->delta->idx.oid.hash, 20);
 345                 hdrlen += 20;
 346         } else {
 347                 if (limit && hdrlen + datalen + 20 >= limit) {
 348                         if (st)
 349                                 close_istream(st);
 350                         free(buf);
 351                         return 0;
 352                 }
 353                 hashwrite(f, header, hdrlen);
 354         }
 355         if (st) {
 356                 datalen = write_large_blob_data(st, f, &entry->idx.oid);
 357                 close_istream(st);
 358         } else {
 359                 hashwrite(f, buf, datalen);
 360                 free(buf);
 361         }
 362
 363         return hdrlen + datalen;
 364 }
 365
 366 /* Return 0 if we will bust the pack-size limit */
 367 static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 368                                 unsigned long limit, int usable_delta)
 369 {
 370         struct packed_git *p = entry->in_pack;
 371         struct pack_window *w_curs = NULL;
 372         struct revindex_entry *revidx;
 373         off_t offset;
 374         enum object_type type = oe_type(entry);
 375         off_t datalen;
 376         unsigned char header[MAX_PACK_OBJECT_HEADER],
 377                       dheader[MAX_PACK_OBJECT_HEADER];
 378         unsigned hdrlen;
 379
 380         if (entry->delta)
 381                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 382                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 383         hdrlen = encode_in_pack_object_header(header, sizeof(header),
 384                                               type, entry->size);
 385
 386         offset = entry->in_pack_offset;
 387         revidx = find_pack_revindex(p, offset);
 388         datalen = revidx[1].offset - offset;
 389         if (!pack_to_stdout && p->index_version > 1 &&
 390             check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 391                 error("bad packed object CRC for %s",
 392                       oid_to_hex(&entry->idx.oid));
 393                 unuse_pack(&w_curs);
 394                 return write_no_reuse_object(f, entry, limit, usable_delta);
 395         }
 396
 397         offset += entry->in_pack_header_size;
 398         datalen -= entry->in_pack_header_size;
 399
 400         if (!pack_to_stdout && p->index_version == 1 &&
 401             check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 402                 error("corrupt packed object for %s",
 403                       oid_to_hex(&entry->idx.oid));
 404                 unuse_pack(&w_curs);
 405                 return write_no_reuse_object(f, entry, limit, usable_delta);
 406         }
 407
 408         if (type == OBJ_OFS_DELTA) {
 409                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 410                 unsigned pos = sizeof(dheader) - 1;
 411                 dheader[pos] = ofs & 127;
 412                 while (ofs >>= 7)
 413                         dheader[--pos] = 128 | (--ofs & 127);
 414                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 415                         unuse_pack(&w_curs);
 416                         return 0;
 417                 }
 418                 hashwrite(f, header, hdrlen);
 419                 hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 420                 hdrlen += sizeof(dheader) - pos;
 421                 reused_delta++;
 422         } else if (type == OBJ_REF_DELTA) {
 423                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 424                         unuse_pack(&w_curs);
 425                         return 0;
 426                 }
 427                 hashwrite(f, header, hdrlen);
 428                 hashwrite(f, entry->delta->idx.oid.hash, 20);
 429                 hdrlen += 20;
 430                 reused_delta++;
 431         } else {
 432                 if (limit && hdrlen + datalen + 20 >= limit) {
 433                         unuse_pack(&w_curs);
 434                         return 0;
 435                 }
 436                 hashwrite(f, header, hdrlen);
 437         }
 438         copy_pack_data(f, p, &w_curs, offset, datalen);
 439         unuse_pack(&w_curs);
 440         reused++;
 441         return hdrlen + datalen;
 442 }
 443
 444 /* Return 0 if we will bust the pack-size limit */
 445 static off_t write_object(struct hashfile *f,
 446                           struct object_entry *entry,
 447                           off_t write_offset)
 448 {
 449         unsigned long limit;
 450         off_t len;
 451         int usable_delta, to_reuse;
 452
 453         if (!pack_to_stdout)
 454                 crc32_begin(f);
 455
 456         /* apply size limit if limited packsize and not first object */
 457         if (!pack_size_limit || !nr_written)
 458                 limit = 0;
 459         else if (pack_size_limit <= write_offset)
 460                 /*
 461                  * the earlier object did not fit the limit; avoid
 462                  * mistaking this with unlimited (i.e. limit = 0).
 463                  */
 464                 limit = 1;
 465         else
 466                 limit = pack_size_limit - write_offset;
 467
 468         if (!entry->delta)
 469                 usable_delta = 0;       /* no delta */
 470         else if (!pack_size_limit)
 471                usable_delta = 1;        /* unlimited packfile */
 472         else if (entry->delta->idx.offset == (off_t)-1)
 473                 usable_delta = 0;       /* base was written to another pack */
 474         else if (entry->delta->idx.offset)
 475                 usable_delta = 1;       /* base already exists in this pack */
 476         else
 477                 usable_delta = 0;       /* base could end up in another pack */
 478
 479         if (!reuse_object)
 480                 to_reuse = 0;   /* explicit */
 481         else if (!entry->in_pack)
 482                 to_reuse = 0;   /* can't reuse what we don't have */
 483         else if (oe_type(entry) == OBJ_REF_DELTA ||
 484                  oe_type(entry) == OBJ_OFS_DELTA)
 485                                 /* check_object() decided it for us ... */
 486                 to_reuse = usable_delta;
 487                                 /* ... but pack split may override that */
 488         else if (oe_type(entry) != entry->in_pack_type)
 489                 to_reuse = 0;   /* pack has delta which is unusable */
 490         else if (entry->delta)
 491                 to_reuse = 0;   /* we want to pack afresh */
 492         else
 493                 to_reuse = 1;   /* we have it in-pack undeltified,
 494                                  * and we do not need to deltify it.
 495                                  */
 496
 497         if (!to_reuse)
 498                 len = write_no_reuse_object(f, entry, limit, usable_delta);
 499         else
 500                 len = write_reuse_object(f, entry, limit, usable_delta);
 501         if (!len)
 502                 return 0;
 503
 504         if (usable_delta)
 505                 written_delta++;
 506         written++;
 507         if (!pack_to_stdout)
 508                 entry->idx.crc32 = crc32_end(f);
 509         return len;
 510 }
 511
 512 enum write_one_status {
 513         WRITE_ONE_SKIP = -1, /* already written */
 514         WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 515         WRITE_ONE_WRITTEN = 1, /* normal */
 516         WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 517 };
 518
 519 static enum write_one_status write_one(struct hashfile *f,
 520                                        struct object_entry *e,
 521                                        off_t *offset)
 522 {
 523         off_t size;
 524         int recursing;
 525
 526         /*
 527          * we set offset to 1 (which is an impossible value) to mark
 528          * the fact that this object is involved in "write its base
 529          * first before writing a deltified object" recursion.
 530          */
 531         recursing = (e->idx.offset == 1);
 532         if (recursing) {
 533                 warning("recursive delta detected for object %s",
 534                         oid_to_hex(&e->idx.oid));
 535                 return WRITE_ONE_RECURSIVE;
 536         } else if (e->idx.offset || e->preferred_base) {
 537                 /* offset is non zero if object is written already. */
 538                 return WRITE_ONE_SKIP;
 539         }
 540
 541         /* if we are deltified, write out base object first. */
 542         if (e->delta) {
 543                 e->idx.offset = 1; /* now recurse */
 544                 switch (write_one(f, e->delta, offset)) {
 545                 case WRITE_ONE_RECURSIVE:
 546                         /* we cannot depend on this one */
 547                         e->delta = NULL;
 548                         break;
 549                 default:
 550                         break;
 551                 case WRITE_ONE_BREAK:
 552                         e->idx.offset = recursing;
 553                         return WRITE_ONE_BREAK;
 554                 }
 555         }
 556
 557         e->idx.offset = *offset;
 558         size = write_object(f, e, *offset);
 559         if (!size) {
 560                 e->idx.offset = recursing;
 561                 return WRITE_ONE_BREAK;
 562         }
 563         written_list[nr_written++] = &e->idx;
 564
 565         /* make sure off_t is sufficiently large not to wrap */
 566         if (signed_add_overflows(*offset, size))
 567                 die("pack too large for current definition of off_t");
 568         *offset += size;
 569         return WRITE_ONE_WRITTEN;
 570 }
 571
 572 static int mark_tagged(const char *path, const struct object_id *oid, int flag,
 573                        void *cb_data)
 574 {
 575         struct object_id peeled;
 576         struct object_entry *entry = packlist_find(&to_pack, oid->hash, NULL);
 577
 578         if (entry)
 579                 entry->tagged = 1;
 580         if (!peel_ref(path, &peeled)) {
 581                 entry = packlist_find(&to_pack, peeled.hash, NULL);
 582                 if (entry)
 583                         entry->tagged = 1;
 584         }
 585         return 0;
 586 }
 587
 588 static inline void add_to_write_order(struct object_entry **wo,
 589                                unsigned int *endp,
 590                                struct object_entry *e)
 591 {
 592         if (e->filled)
 593                 return;
 594         wo[(*endp)++] = e;
 595         e->filled = 1;
 596 }
 597
 598 static void add_descendants_to_write_order(struct object_entry **wo,
 599                                            unsigned int *endp,
 600                                            struct object_entry *e)
 601 {
 602         int add_to_order = 1;
 603         while (e) {
 604                 if (add_to_order) {
 605                         struct object_entry *s;
 606                         /* add this node... */
 607                         add_to_write_order(wo, endp, e);
 608                         /* all its siblings... */
 609                         for (s = e->delta_sibling; s; s = s->delta_sibling) {
 610                                 add_to_write_order(wo, endp, s);
 611                         }
 612                 }
 613                 /* drop down a level to add left subtree nodes if possible */
 614                 if (e->delta_child) {
 615                         add_to_order = 1;
 616                         e = e->delta_child;
 617                 } else {
 618                         add_to_order = 0;
 619                         /* our sibling might have some children, it is next */
 620                         if (e->delta_sibling) {
 621                                 e = e->delta_sibling;
 622                                 continue;
 623                         }
 624                         /* go back to our parent node */
 625                         e = e->delta;
 626                         while (e && !e->delta_sibling) {
 627                                 /* we're on the right side of a subtree, keep
 628                                  * going up until we can go right again */
 629                                 e = e->delta;
 630                         }
 631                         if (!e) {
 632                                 /* done- we hit our original root node */
 633                                 return;
 634                         }
 635                         /* pass it off to sibling at this level */
 636                         e = e->delta_sibling;
 637                 }
 638         };
 639 }
 640
 641 static void add_family_to_write_order(struct object_entry **wo,
 642                                       unsigned int *endp,
 643                                       struct object_entry *e)
 644 {
 645         struct object_entry *root;
 646
 647         for (root = e; root->delta; root = root->delta)
 648                 ; /* nothing */
 649         add_descendants_to_write_order(wo, endp, root);
 650 }
 651
 652 static struct object_entry **compute_write_order(void)
 653 {
 654         unsigned int i, wo_end, last_untagged;
 655
 656         struct object_entry **wo;
 657         struct object_entry *objects = to_pack.objects;
 658
 659         for (i = 0; i < to_pack.nr_objects; i++) {
 660                 objects[i].tagged = 0;
 661                 objects[i].filled = 0;
 662                 objects[i].delta_child = NULL;
 663                 objects[i].delta_sibling = NULL;
 664         }
 665
 666         /*
 667          * Fully connect delta_child/delta_sibling network.
 668          * Make sure delta_sibling is sorted in the original
 669          * recency order.
 670          */
 671         for (i = to_pack.nr_objects; i > 0;) {
 672                 struct object_entry *e = &objects[--i];
 673                 if (!e->delta)
 674                         continue;
 675                 /* Mark me as the first child */
 676                 e->delta_sibling = e->delta->delta_child;
 677                 e->delta->delta_child = e;
 678         }
 679
 680         /*
 681          * Mark objects that are at the tip of tags.
 682          */
 683         for_each_tag_ref(mark_tagged, NULL);
 684
 685         /*
 686          * Give the objects in the original recency order until
 687          * we see a tagged tip.
 688          */
 689         ALLOC_ARRAY(wo, to_pack.nr_objects);
 690         for (i = wo_end = 0; i < to_pack.nr_objects; i++) {
 691                 if (objects[i].tagged)
 692                         break;
 693                 add_to_write_order(wo, &wo_end, &objects[i]);
 694         }
 695         last_untagged = i;
 696
 697         /*
 698          * Then fill all the tagged tips.
 699          */
 700         for (; i < to_pack.nr_objects; i++) {
 701                 if (objects[i].tagged)
 702                         add_to_write_order(wo, &wo_end, &objects[i]);
 703         }
 704
 705         /*
 706          * And then all remaining commits and tags.
 707          */
 708         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 709                 if (oe_type(&objects[i]) != OBJ_COMMIT &&
 710                     oe_type(&objects[i]) != OBJ_TAG)
 711                         continue;
 712                 add_to_write_order(wo, &wo_end, &objects[i]);
 713         }
 714
 715         /*
 716          * And then all the trees.
 717          */
 718         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 719                 if (oe_type(&objects[i]) != OBJ_TREE)
 720                         continue;
 721                 add_to_write_order(wo, &wo_end, &objects[i]);
 722         }
 723
 724         /*
 725          * Finally all the rest in really tight order
 726          */
 727         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 728                 if (!objects[i].filled)
 729                         add_family_to_write_order(wo, &wo_end, &objects[i]);
 730         }
 731
 732         if (wo_end != to_pack.nr_objects)
 733                 die("ordered %u objects, expected %"PRIu32, wo_end, to_pack.nr_objects);
 734
 735         return wo;
 736 }
 737
 738 static off_t write_reused_pack(struct hashfile *f)
 739 {
 740         unsigned char buffer[8192];
 741         off_t to_write, total;
 742         int fd;
 743
 744         if (!is_pack_valid(reuse_packfile))
 745                 die("packfile is invalid: %s", reuse_packfile->pack_name);
 746
 747         fd = git_open(reuse_packfile->pack_name);
 748         if (fd < 0)
 749                 die_errno("unable to open packfile for reuse: %s",
 750                           reuse_packfile->pack_name);
 751
 752         if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
 753                 die_errno("unable to seek in reused packfile");
 754
 755         if (reuse_packfile_offset < 0)
 756                 reuse_packfile_offset = reuse_packfile->pack_size - 20;
 757
 758         total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 759
 760         while (to_write) {
 761                 int read_pack = xread(fd, buffer, sizeof(buffer));
 762
 763                 if (read_pack <= 0)
 764                         die_errno("unable to read from reused packfile");
 765
 766                 if (read_pack > to_write)
 767                         read_pack = to_write;
 768
 769                 hashwrite(f, buffer, read_pack);
 770                 to_write -= read_pack;
 771
 772                 /*
 773                  * We don't know the actual number of objects written,
 774                  * only how many bytes written, how many bytes total, and
 775                  * how many objects total. So we can fake it by pretending all
 776                  * objects we are writing are the same size. This gives us a
 777                  * smooth progress meter, and at the end it matches the true
 778                  * answer.
 779                  */
 780                 written = reuse_packfile_objects *
 781                                 (((double)(total - to_write)) / total);
 782                 display_progress(progress_state, written);
 783         }
 784
 785         close(fd);
 786         written = reuse_packfile_objects;
 787         display_progress(progress_state, written);
 788         return reuse_packfile_offset - sizeof(struct pack_header);
 789 }
 790
 791 static const char no_split_warning[] = N_(
 792 "disabling bitmap writing, packs are split due to pack.packSizeLimit"
 793 );
 794
 795 static void write_pack_file(void)
 796 {
 797         uint32_t i = 0, j;
 798         struct hashfile *f;
 799         off_t offset;
 800         uint32_t nr_remaining = nr_result;
 801         time_t last_mtime = 0;
 802         struct object_entry **write_order;
 803
 804         if (progress > pack_to_stdout)
 805                 progress_state = start_progress(_("Writing objects"), nr_result);
 806         ALLOC_ARRAY(written_list, to_pack.nr_objects);
 807         write_order = compute_write_order();
 808
 809         do {
 810                 struct object_id oid;
 811                 char *pack_tmp_name = NULL;
 812
 813                 if (pack_to_stdout)
 814                         f = hashfd_throughput(1, "<stdout>", progress_state);
 815                 else
 816                         f = create_tmp_packfile(&pack_tmp_name);
 817
 818                 offset = write_pack_header(f, nr_remaining);
 819
 820                 if (reuse_packfile) {
 821                         off_t packfile_size;
 822                         assert(pack_to_stdout);
 823
 824                         packfile_size = write_reused_pack(f);
 825                         offset += packfile_size;
 826                 }
 827
 828                 nr_written = 0;
 829                 for (; i < to_pack.nr_objects; i++) {
 830                         struct object_entry *e = write_order[i];
 831                         if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 832                                 break;
 833                         display_progress(progress_state, written);
 834                 }
 835
 836                 /*
 837                  * Did we write the wrong # entries in the header?
 838                  * If so, rewrite it like in fast-import
 839                  */
 840                 if (pack_to_stdout) {
 841                         hashclose(f, oid.hash, CSUM_CLOSE);
 842                 } else if (nr_written == nr_remaining) {
 843                         hashclose(f, oid.hash, CSUM_FSYNC);
 844                 } else {
 845                         int fd = hashclose(f, oid.hash, 0);
 846                         fixup_pack_header_footer(fd, oid.hash, pack_tmp_name,
 847                                                  nr_written, oid.hash, offset);
 848                         close(fd);
 849                         if (write_bitmap_index) {
 850                                 warning(_(no_split_warning));
 851                                 write_bitmap_index = 0;
 852                         }
 853                 }
 854
 855                 if (!pack_to_stdout) {
 856                         struct stat st;
 857                         struct strbuf tmpname = STRBUF_INIT;
 858
 859                         /*
 860                          * Packs are runtime accessed in their mtime
 861                          * order since newer packs are more likely to contain
 862                          * younger objects.  So if we are creating multiple
 863                          * packs then we should modify the mtime of later ones
 864                          * to preserve this property.
 865                          */
 866                         if (stat(pack_tmp_name, &st) < 0) {
 867                                 warning_errno("failed to stat %s", pack_tmp_name);
 868                         } else if (!last_mtime) {
 869                                 last_mtime = st.st_mtime;
 870                         } else {
 871                                 struct utimbuf utb;
 872                                 utb.actime = st.st_atime;
 873                                 utb.modtime = --last_mtime;
 874                                 if (utime(pack_tmp_name, &utb) < 0)
 875                                         warning_errno("failed utime() on %s", pack_tmp_name);
 876                         }
 877
 878                         strbuf_addf(&tmpname, "%s-", base_name);
 879
 880                         if (write_bitmap_index) {
 881                                 bitmap_writer_set_checksum(oid.hash);
 882                                 bitmap_writer_build_type_index(
 883                                         &to_pack, 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->hash))
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         oe_set_type(entry, type);
1072         if (exclude)
1073                 entry->preferred_base = 1;
1074         else
1075                 nr_result++;
1076         if (found_pack) {
1077                 entry->in_pack = found_pack;
1078                 entry->in_pack_offset = found_offset;
1079         }
1080
1081         entry->no_try_delta = no_try_delta;
1082 }
1083
1084 static const char no_closure_warning[] = N_(
1085 "disabling bitmap writing, as some objects are not being packed"
1086 );
1087
1088 static int add_object_entry(const struct object_id *oid, enum object_type type,
1089                             const char *name, int exclude)
1090 {
1091         struct packed_git *found_pack = NULL;
1092         off_t found_offset = 0;
1093         uint32_t index_pos;
1094
1095         if (have_duplicate_entry(oid, exclude, &index_pos))
1096                 return 0;
1097
1098         if (!want_object_in_pack(oid, exclude, &found_pack, &found_offset)) {
1099                 /* The pack is missing an object, so it will not have closure */
1100                 if (write_bitmap_index) {
1101                         warning(_(no_closure_warning));
1102                         write_bitmap_index = 0;
1103                 }
1104                 return 0;
1105         }
1106
1107         create_object_entry(oid, type, pack_name_hash(name),
1108                             exclude, name && no_try_delta(name),
1109                             index_pos, found_pack, found_offset);
1110
1111         display_progress(progress_state, nr_result);
1112         return 1;
1113 }
1114
1115 static int add_object_entry_from_bitmap(const struct object_id *oid,
1116                                         enum object_type type,
1117                                         int flags, uint32_t name_hash,
1118                                         struct packed_git *pack, off_t offset)
1119 {
1120         uint32_t index_pos;
1121
1122         if (have_duplicate_entry(oid, 0, &index_pos))
1123                 return 0;
1124
1125         if (!want_object_in_pack(oid, 0, &pack, &offset))
1126                 return 0;
1127
1128         create_object_entry(oid, type, name_hash, 0, 0, index_pos, pack, offset);
1129
1130         display_progress(progress_state, nr_result);
1131         return 1;
1132 }
1133
1134 struct pbase_tree_cache {
1135         struct object_id oid;
1136         int ref;
1137         int temporary;
1138         void *tree_data;
1139         unsigned long tree_size;
1140 };
1141
1142 static struct pbase_tree_cache *(pbase_tree_cache[256]);
1143 static int pbase_tree_cache_ix(const struct object_id *oid)
1144 {
1145         return oid->hash[0] % ARRAY_SIZE(pbase_tree_cache);
1146 }
1147 static int pbase_tree_cache_ix_incr(int ix)
1148 {
1149         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
1150 }
1151
1152 static struct pbase_tree {
1153         struct pbase_tree *next;
1154         /* This is a phony "cache" entry; we are not
1155          * going to evict it or find it through _get()
1156          * mechanism -- this is for the toplevel node that
1157          * would almost always change with any commit.
1158          */
1159         struct pbase_tree_cache pcache;
1160 } *pbase_tree;
1161
1162 static struct pbase_tree_cache *pbase_tree_get(const struct object_id *oid)
1163 {
1164         struct pbase_tree_cache *ent, *nent;
1165         void *data;
1166         unsigned long size;
1167         enum object_type type;
1168         int neigh;
1169         int my_ix = pbase_tree_cache_ix(oid);
1170         int available_ix = -1;
1171
1172         /* pbase-tree-cache acts as a limited hashtable.
1173          * your object will be found at your index or within a few
1174          * slots after that slot if it is cached.
1175          */
1176         for (neigh = 0; neigh < 8; neigh++) {
1177                 ent = pbase_tree_cache[my_ix];
1178                 if (ent && !oidcmp(&ent->oid, oid)) {
1179                         ent->ref++;
1180                         return ent;
1181                 }
1182                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
1183                          ((0 <= available_ix) &&
1184                           (!ent && pbase_tree_cache[available_ix])))
1185                         available_ix = my_ix;
1186                 if (!ent)
1187                         break;
1188                 my_ix = pbase_tree_cache_ix_incr(my_ix);
1189         }
1190
1191         /* Did not find one.  Either we got a bogus request or
1192          * we need to read and perhaps cache.
1193          */
1194         data = read_object_file(oid, &type, &size);
1195         if (!data)
1196                 return NULL;
1197         if (type != OBJ_TREE) {
1198                 free(data);
1199                 return NULL;
1200         }
1201
1202         /* We need to either cache or return a throwaway copy */
1203
1204         if (available_ix < 0)
1205                 ent = NULL;
1206         else {
1207                 ent = pbase_tree_cache[available_ix];
1208                 my_ix = available_ix;
1209         }
1210
1211         if (!ent) {
1212                 nent = xmalloc(sizeof(*nent));
1213                 nent->temporary = (available_ix < 0);
1214         }
1215         else {
1216                 /* evict and reuse */
1217                 free(ent->tree_data);
1218                 nent = ent;
1219         }
1220         oidcpy(&nent->oid, oid);
1221         nent->tree_data = data;
1222         nent->tree_size = size;
1223         nent->ref = 1;
1224         if (!nent->temporary)
1225                 pbase_tree_cache[my_ix] = nent;
1226         return nent;
1227 }
1228
1229 static void pbase_tree_put(struct pbase_tree_cache *cache)
1230 {
1231         if (!cache->temporary) {
1232                 cache->ref--;
1233                 return;
1234         }
1235         free(cache->tree_data);
1236         free(cache);
1237 }
1238
1239 static int name_cmp_len(const char *name)
1240 {
1241         int i;
1242         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1243                 ;
1244         return i;
1245 }
1246
1247 static void add_pbase_object(struct tree_desc *tree,
1248                              const char *name,
1249                              int cmplen,
1250                              const char *fullname)
1251 {
1252         struct name_entry entry;
1253         int cmp;
1254
1255         while (tree_entry(tree,&entry)) {
1256                 if (S_ISGITLINK(entry.mode))
1257                         continue;
1258                 cmp = tree_entry_len(&entry) != cmplen ? 1 :
1259                       memcmp(name, entry.path, cmplen);
1260                 if (cmp > 0)
1261                         continue;
1262                 if (cmp < 0)
1263                         return;
1264                 if (name[cmplen] != '/') {
1265                         add_object_entry(entry.oid,
1266                                          object_type(entry.mode),
1267                                          fullname, 1);
1268                         return;
1269                 }
1270                 if (S_ISDIR(entry.mode)) {
1271                         struct tree_desc sub;
1272                         struct pbase_tree_cache *tree;
1273                         const char *down = name+cmplen+1;
1274                         int downlen = name_cmp_len(down);
1275
1276                         tree = pbase_tree_get(entry.oid);
1277                         if (!tree)
1278                                 return;
1279                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1280
1281                         add_pbase_object(&sub, down, downlen, fullname);
1282                         pbase_tree_put(tree);
1283                 }
1284         }
1285 }
1286
1287 static unsigned *done_pbase_paths;
1288 static int done_pbase_paths_num;
1289 static int done_pbase_paths_alloc;
1290 static int done_pbase_path_pos(unsigned hash)
1291 {
1292         int lo = 0;
1293         int hi = done_pbase_paths_num;
1294         while (lo < hi) {
1295                 int mi = lo + (hi - lo) / 2;
1296                 if (done_pbase_paths[mi] == hash)
1297                         return mi;
1298                 if (done_pbase_paths[mi] < hash)
1299                         hi = mi;
1300                 else
1301                         lo = mi + 1;
1302         }
1303         return -lo-1;
1304 }
1305
1306 static int check_pbase_path(unsigned hash)
1307 {
1308         int pos = done_pbase_path_pos(hash);
1309         if (0 <= pos)
1310                 return 1;
1311         pos = -pos - 1;
1312         ALLOC_GROW(done_pbase_paths,
1313                    done_pbase_paths_num + 1,
1314                    done_pbase_paths_alloc);
1315         done_pbase_paths_num++;
1316         if (pos < done_pbase_paths_num)
1317                 MOVE_ARRAY(done_pbase_paths + pos + 1, done_pbase_paths + pos,
1318                            done_pbase_paths_num - pos - 1);
1319         done_pbase_paths[pos] = hash;
1320         return 0;
1321 }
1322
1323 static void add_preferred_base_object(const char *name)
1324 {
1325         struct pbase_tree *it;
1326         int cmplen;
1327         unsigned hash = pack_name_hash(name);
1328
1329         if (!num_preferred_base || check_pbase_path(hash))
1330                 return;
1331
1332         cmplen = name_cmp_len(name);
1333         for (it = pbase_tree; it; it = it->next) {
1334                 if (cmplen == 0) {
1335                         add_object_entry(&it->pcache.oid, OBJ_TREE, NULL, 1);
1336                 }
1337                 else {
1338                         struct tree_desc tree;
1339                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1340                         add_pbase_object(&tree, name, cmplen, name);
1341                 }
1342         }
1343 }
1344
1345 static void add_preferred_base(struct object_id *oid)
1346 {
1347         struct pbase_tree *it;
1348         void *data;
1349         unsigned long size;
1350         struct object_id tree_oid;
1351
1352         if (window <= num_preferred_base++)
1353                 return;
1354
1355         data = read_object_with_reference(oid, tree_type, &size, &tree_oid);
1356         if (!data)
1357                 return;
1358
1359         for (it = pbase_tree; it; it = it->next) {
1360                 if (!oidcmp(&it->pcache.oid, &tree_oid)) {
1361                         free(data);
1362                         return;
1363                 }
1364         }
1365
1366         it = xcalloc(1, sizeof(*it));
1367         it->next = pbase_tree;
1368         pbase_tree = it;
1369
1370         oidcpy(&it->pcache.oid, &tree_oid);
1371         it->pcache.tree_data = data;
1372         it->pcache.tree_size = size;
1373 }
1374
1375 static void cleanup_preferred_base(void)
1376 {
1377         struct pbase_tree *it;
1378         unsigned i;
1379
1380         it = pbase_tree;
1381         pbase_tree = NULL;
1382         while (it) {
1383                 struct pbase_tree *tmp = it;
1384                 it = tmp->next;
1385                 free(tmp->pcache.tree_data);
1386                 free(tmp);
1387         }
1388
1389         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1390                 if (!pbase_tree_cache[i])
1391                         continue;
1392                 free(pbase_tree_cache[i]->tree_data);
1393                 FREE_AND_NULL(pbase_tree_cache[i]);
1394         }
1395
1396         FREE_AND_NULL(done_pbase_paths);
1397         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1398 }
1399
1400 static void check_object(struct object_entry *entry)
1401 {
1402         if (entry->in_pack) {
1403                 struct packed_git *p = entry->in_pack;
1404                 struct pack_window *w_curs = NULL;
1405                 const unsigned char *base_ref = NULL;
1406                 struct object_entry *base_entry;
1407                 unsigned long used, used_0;
1408                 unsigned long avail;
1409                 off_t ofs;
1410                 unsigned char *buf, c;
1411                 enum object_type type;
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                                                    &type,
1421                                                    &entry->size);
1422                 if (used == 0)
1423                         goto give_up;
1424
1425                 if (type < 0)
1426                         BUG("invalid type %d", type);
1427                 entry->in_pack_type = type;
1428
1429                 /*
1430                  * Determine if this is a delta and if so whether we can
1431                  * reuse it or not.  Otherwise let's find out as cheaply as
1432                  * possible what the actual type and size for this object is.
1433                  */
1434                 switch (entry->in_pack_type) {
1435                 default:
1436                         /* Not a delta hence we've already got all we need. */
1437                         oe_set_type(entry, entry->in_pack_type);
1438                         entry->in_pack_header_size = used;
1439                         if (oe_type(entry) < OBJ_COMMIT || oe_type(entry) > OBJ_BLOB)
1440                                 goto give_up;
1441                         unuse_pack(&w_curs);
1442                         return;
1443                 case OBJ_REF_DELTA:
1444                         if (reuse_delta && !entry->preferred_base)
1445                                 base_ref = use_pack(p, &w_curs,
1446                                                 entry->in_pack_offset + used, NULL);
1447                         entry->in_pack_header_size = used + 20;
1448                         break;
1449                 case OBJ_OFS_DELTA:
1450                         buf = use_pack(p, &w_curs,
1451                                        entry->in_pack_offset + used, NULL);
1452                         used_0 = 0;
1453                         c = buf[used_0++];
1454                         ofs = c & 127;
1455                         while (c & 128) {
1456                                 ofs += 1;
1457                                 if (!ofs || MSB(ofs, 7)) {
1458                                         error("delta base offset overflow in pack for %s",
1459                                               oid_to_hex(&entry->idx.oid));
1460                                         goto give_up;
1461                                 }
1462                                 c = buf[used_0++];
1463                                 ofs = (ofs << 7) + (c & 127);
1464                         }
1465                         ofs = entry->in_pack_offset - ofs;
1466                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1467                                 error("delta base offset out of bound for %s",
1468                                       oid_to_hex(&entry->idx.oid));
1469                                 goto give_up;
1470                         }
1471                         if (reuse_delta && !entry->preferred_base) {
1472                                 struct revindex_entry *revidx;
1473                                 revidx = find_pack_revindex(p, ofs);
1474                                 if (!revidx)
1475                                         goto give_up;
1476                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1477                         }
1478                         entry->in_pack_header_size = used + used_0;
1479                         break;
1480                 }
1481
1482                 if (base_ref && (base_entry = packlist_find(&to_pack, base_ref, NULL))) {
1483                         /*
1484                          * If base_ref was set above that means we wish to
1485                          * reuse delta data, and we even found that base
1486                          * in the list of objects we want to pack. Goodie!
1487                          *
1488                          * Depth value does not matter - find_deltas() will
1489                          * never consider reused delta as the base object to
1490                          * deltify other objects against, in order to avoid
1491                          * circular deltas.
1492                          */
1493                         oe_set_type(entry, entry->in_pack_type);
1494                         entry->delta = base_entry;
1495                         entry->delta_size = entry->size;
1496                         entry->delta_sibling = base_entry->delta_child;
1497                         base_entry->delta_child = entry;
1498                         unuse_pack(&w_curs);
1499                         return;
1500                 }
1501
1502                 if (oe_type(entry)) {
1503                         /*
1504                          * This must be a delta and we already know what the
1505                          * final object type is.  Let's extract the actual
1506                          * object size from the delta header.
1507                          */
1508                         entry->size = get_size_from_delta(p, &w_curs,
1509                                         entry->in_pack_offset + entry->in_pack_header_size);
1510                         if (entry->size == 0)
1511                                 goto give_up;
1512                         unuse_pack(&w_curs);
1513                         return;
1514                 }
1515
1516                 /*
1517                  * No choice but to fall back to the recursive delta walk
1518                  * with sha1_object_info() to find about the object type
1519                  * at this point...
1520                  */
1521                 give_up:
1522                 unuse_pack(&w_curs);
1523         }
1524
1525         oe_set_type(entry, oid_object_info(&entry->idx.oid, &entry->size));
1526         /*
1527          * The error condition is checked in prepare_pack().  This is
1528          * to permit a missing preferred base object to be ignored
1529          * as a preferred base.  Doing so can result in a larger
1530          * pack file, but the transfer will still take place.
1531          */
1532 }
1533
1534 static int pack_offset_sort(const void *_a, const void *_b)
1535 {
1536         const struct object_entry *a = *(struct object_entry **)_a;
1537         const struct object_entry *b = *(struct object_entry **)_b;
1538
1539         /* avoid filesystem trashing with loose objects */
1540         if (!a->in_pack && !b->in_pack)
1541                 return oidcmp(&a->idx.oid, &b->idx.oid);
1542
1543         if (a->in_pack < b->in_pack)
1544                 return -1;
1545         if (a->in_pack > b->in_pack)
1546                 return 1;
1547         return a->in_pack_offset < b->in_pack_offset ? -1 :
1548                         (a->in_pack_offset > b->in_pack_offset);
1549 }
1550
1551 /*
1552  * Drop an on-disk delta we were planning to reuse. Naively, this would
1553  * just involve blanking out the "delta" field, but we have to deal
1554  * with some extra book-keeping:
1555  *
1556  *   1. Removing ourselves from the delta_sibling linked list.
1557  *
1558  *   2. Updating our size/type to the non-delta representation. These were
1559  *      either not recorded initially (size) or overwritten with the delta type
1560  *      (type) when check_object() decided to reuse the delta.
1561  *
1562  *   3. Resetting our delta depth, as we are now a base object.
1563  */
1564 static void drop_reused_delta(struct object_entry *entry)
1565 {
1566         struct object_entry **p = &entry->delta->delta_child;
1567         struct object_info oi = OBJECT_INFO_INIT;
1568         enum object_type type;
1569
1570         while (*p) {
1571                 if (*p == entry)
1572                         *p = (*p)->delta_sibling;
1573                 else
1574                         p = &(*p)->delta_sibling;
1575         }
1576         entry->delta = NULL;
1577         entry->depth = 0;
1578
1579         oi.sizep = &entry->size;
1580         oi.typep = &type;
1581         if (packed_object_info(entry->in_pack, entry->in_pack_offset, &oi) < 0) {
1582                 /*
1583                  * We failed to get the info from this pack for some reason;
1584                  * fall back to sha1_object_info, which may find another copy.
1585                  * And if that fails, the error will be recorded in oe_type(entry)
1586                  * and dealt with in prepare_pack().
1587                  */
1588                 oe_set_type(entry, oid_object_info(&entry->idx.oid,
1589                                                    &entry->size));
1590         } else {
1591                 oe_set_type(entry, type);
1592         }
1593 }
1594
1595 /*
1596  * Follow the chain of deltas from this entry onward, throwing away any links
1597  * that cause us to hit a cycle (as determined by the DFS state flags in
1598  * the entries).
1599  *
1600  * We also detect too-long reused chains that would violate our --depth
1601  * limit.
1602  */
1603 static void break_delta_chains(struct object_entry *entry)
1604 {
1605         /*
1606          * The actual depth of each object we will write is stored as an int,
1607          * as it cannot exceed our int "depth" limit. But before we break
1608          * changes based no that limit, we may potentially go as deep as the
1609          * number of objects, which is elsewhere bounded to a uint32_t.
1610          */
1611         uint32_t total_depth;
1612         struct object_entry *cur, *next;
1613
1614         for (cur = entry, total_depth = 0;
1615              cur;
1616              cur = cur->delta, total_depth++) {
1617                 if (cur->dfs_state == DFS_DONE) {
1618                         /*
1619                          * We've already seen this object and know it isn't
1620                          * part of a cycle. We do need to append its depth
1621                          * to our count.
1622                          */
1623                         total_depth += cur->depth;
1624                         break;
1625                 }
1626
1627                 /*
1628                  * We break cycles before looping, so an ACTIVE state (or any
1629                  * other cruft which made its way into the state variable)
1630                  * is a bug.
1631                  */
1632                 if (cur->dfs_state != DFS_NONE)
1633                         die("BUG: confusing delta dfs state in first pass: %d",
1634                             cur->dfs_state);
1635
1636                 /*
1637                  * Now we know this is the first time we've seen the object. If
1638                  * it's not a delta, we're done traversing, but we'll mark it
1639                  * done to save time on future traversals.
1640                  */
1641                 if (!cur->delta) {
1642                         cur->dfs_state = DFS_DONE;
1643                         break;
1644                 }
1645
1646                 /*
1647                  * Mark ourselves as active and see if the next step causes
1648                  * us to cycle to another active object. It's important to do
1649                  * this _before_ we loop, because it impacts where we make the
1650                  * cut, and thus how our total_depth counter works.
1651                  * E.g., We may see a partial loop like:
1652                  *
1653                  *   A -> B -> C -> D -> B
1654                  *
1655                  * Cutting B->C breaks the cycle. But now the depth of A is
1656                  * only 1, and our total_depth counter is at 3. The size of the
1657                  * error is always one less than the size of the cycle we
1658                  * broke. Commits C and D were "lost" from A's chain.
1659                  *
1660                  * If we instead cut D->B, then the depth of A is correct at 3.
1661                  * We keep all commits in the chain that we examined.
1662                  */
1663                 cur->dfs_state = DFS_ACTIVE;
1664                 if (cur->delta->dfs_state == DFS_ACTIVE) {
1665                         drop_reused_delta(cur);
1666                         cur->dfs_state = DFS_DONE;
1667                         break;
1668                 }
1669         }
1670
1671         /*
1672          * And now that we've gone all the way to the bottom of the chain, we
1673          * need to clear the active flags and set the depth fields as
1674          * appropriate. Unlike the loop above, which can quit when it drops a
1675          * delta, we need to keep going to look for more depth cuts. So we need
1676          * an extra "next" pointer to keep going after we reset cur->delta.
1677          */
1678         for (cur = entry; cur; cur = next) {
1679                 next = cur->delta;
1680
1681                 /*
1682                  * We should have a chain of zero or more ACTIVE states down to
1683                  * a final DONE. We can quit after the DONE, because either it
1684                  * has no bases, or we've already handled them in a previous
1685                  * call.
1686                  */
1687                 if (cur->dfs_state == DFS_DONE)
1688                         break;
1689                 else if (cur->dfs_state != DFS_ACTIVE)
1690                         die("BUG: confusing delta dfs state in second pass: %d",
1691                             cur->dfs_state);
1692
1693                 /*
1694                  * If the total_depth is more than depth, then we need to snip
1695                  * the chain into two or more smaller chains that don't exceed
1696                  * the maximum depth. Most of the resulting chains will contain
1697                  * (depth + 1) entries (i.e., depth deltas plus one base), and
1698                  * the last chain (i.e., the one containing entry) will contain
1699                  * whatever entries are left over, namely
1700                  * (total_depth % (depth + 1)) of them.
1701                  *
1702                  * Since we are iterating towards decreasing depth, we need to
1703                  * decrement total_depth as we go, and we need to write to the
1704                  * entry what its final depth will be after all of the
1705                  * snipping. Since we're snipping into chains of length (depth
1706                  * + 1) entries, the final depth of an entry will be its
1707                  * original depth modulo (depth + 1). Any time we encounter an
1708                  * entry whose final depth is supposed to be zero, we snip it
1709                  * from its delta base, thereby making it so.
1710                  */
1711                 cur->depth = (total_depth--) % (depth + 1);
1712                 if (!cur->depth)
1713                         drop_reused_delta(cur);
1714
1715                 cur->dfs_state = DFS_DONE;
1716         }
1717 }
1718
1719 static void get_object_details(void)
1720 {
1721         uint32_t i;
1722         struct object_entry **sorted_by_offset;
1723
1724         sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
1725         for (i = 0; i < to_pack.nr_objects; i++)
1726                 sorted_by_offset[i] = to_pack.objects + i;
1727         QSORT(sorted_by_offset, to_pack.nr_objects, pack_offset_sort);
1728
1729         for (i = 0; i < to_pack.nr_objects; i++) {
1730                 struct object_entry *entry = sorted_by_offset[i];
1731                 check_object(entry);
1732                 if (big_file_threshold < entry->size)
1733                         entry->no_try_delta = 1;
1734         }
1735
1736         /*
1737          * This must happen in a second pass, since we rely on the delta
1738          * information for the whole list being completed.
1739          */
1740         for (i = 0; i < to_pack.nr_objects; i++)
1741                 break_delta_chains(&to_pack.objects[i]);
1742
1743         free(sorted_by_offset);
1744 }
1745
1746 /*
1747  * We search for deltas in a list sorted by type, by filename hash, and then
1748  * by size, so that we see progressively smaller and smaller files.
1749  * That's because we prefer deltas to be from the bigger file
1750  * to the smaller -- deletes are potentially cheaper, but perhaps
1751  * more importantly, the bigger file is likely the more recent
1752  * one.  The deepest deltas are therefore the oldest objects which are
1753  * less susceptible to be accessed often.
1754  */
1755 static int type_size_sort(const void *_a, const void *_b)
1756 {
1757         const struct object_entry *a = *(struct object_entry **)_a;
1758         const struct object_entry *b = *(struct object_entry **)_b;
1759         enum object_type a_type = oe_type(a);
1760         enum object_type b_type = oe_type(b);
1761
1762         if (a_type > b_type)
1763                 return -1;
1764         if (a_type < b_type)
1765                 return 1;
1766         if (a->hash > b->hash)
1767                 return -1;
1768         if (a->hash < b->hash)
1769                 return 1;
1770         if (a->preferred_base > b->preferred_base)
1771                 return -1;
1772         if (a->preferred_base < b->preferred_base)
1773                 return 1;
1774         if (a->size > b->size)
1775                 return -1;
1776         if (a->size < b->size)
1777                 return 1;
1778         return a < b ? -1 : (a > b);  /* newest first */
1779 }
1780
1781 struct unpacked {
1782         struct object_entry *entry;
1783         void *data;
1784         struct delta_index *index;
1785         unsigned depth;
1786 };
1787
1788 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1789                            unsigned long delta_size)
1790 {
1791         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1792                 return 0;
1793
1794         if (delta_size < cache_max_small_delta_size)
1795                 return 1;
1796
1797         /* cache delta, if objects are large enough compared to delta size */
1798         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1799                 return 1;
1800
1801         return 0;
1802 }
1803
1804 #ifndef NO_PTHREADS
1805
1806 static pthread_mutex_t read_mutex;
1807 #define read_lock()             pthread_mutex_lock(&read_mutex)
1808 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1809
1810 static pthread_mutex_t cache_mutex;
1811 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1812 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1813
1814 static pthread_mutex_t progress_mutex;
1815 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1816 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1817
1818 #else
1819
1820 #define read_lock()             (void)0
1821 #define read_unlock()           (void)0
1822 #define cache_lock()            (void)0
1823 #define cache_unlock()          (void)0
1824 #define progress_lock()         (void)0
1825 #define progress_unlock()       (void)0
1826
1827 #endif
1828
1829 static int try_delta(struct unpacked *trg, struct unpacked *src,
1830                      unsigned max_depth, unsigned long *mem_usage)
1831 {
1832         struct object_entry *trg_entry = trg->entry;
1833         struct object_entry *src_entry = src->entry;
1834         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1835         unsigned ref_depth;
1836         enum object_type type;
1837         void *delta_buf;
1838
1839         /* Don't bother doing diffs between different types */
1840         if (oe_type(trg_entry) != oe_type(src_entry))
1841                 return -1;
1842
1843         /*
1844          * We do not bother to try a delta that we discarded on an
1845          * earlier try, but only when reusing delta data.  Note that
1846          * src_entry that is marked as the preferred_base should always
1847          * be considered, as even if we produce a suboptimal delta against
1848          * it, we will still save the transfer cost, as we already know
1849          * the other side has it and we won't send src_entry at all.
1850          */
1851         if (reuse_delta && trg_entry->in_pack &&
1852             trg_entry->in_pack == src_entry->in_pack &&
1853             !src_entry->preferred_base &&
1854             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1855             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1856                 return 0;
1857
1858         /* Let's not bust the allowed depth. */
1859         if (src->depth >= max_depth)
1860                 return 0;
1861
1862         /* Now some size filtering heuristics. */
1863         trg_size = trg_entry->size;
1864         if (!trg_entry->delta) {
1865                 max_size = trg_size/2 - 20;
1866                 ref_depth = 1;
1867         } else {
1868                 max_size = trg_entry->delta_size;
1869                 ref_depth = trg->depth;
1870         }
1871         max_size = (uint64_t)max_size * (max_depth - src->depth) /
1872                                                 (max_depth - ref_depth + 1);
1873         if (max_size == 0)
1874                 return 0;
1875         src_size = src_entry->size;
1876         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1877         if (sizediff >= max_size)
1878                 return 0;
1879         if (trg_size < src_size / 32)
1880                 return 0;
1881
1882         /* Load data if not already done */
1883         if (!trg->data) {
1884                 read_lock();
1885                 trg->data = read_object_file(&trg_entry->idx.oid, &type, &sz);
1886                 read_unlock();
1887                 if (!trg->data)
1888                         die("object %s cannot be read",
1889                             oid_to_hex(&trg_entry->idx.oid));
1890                 if (sz != trg_size)
1891                         die("object %s inconsistent object length (%lu vs %lu)",
1892                             oid_to_hex(&trg_entry->idx.oid), sz,
1893                             trg_size);
1894                 *mem_usage += sz;
1895         }
1896         if (!src->data) {
1897                 read_lock();
1898                 src->data = read_object_file(&src_entry->idx.oid, &type, &sz);
1899                 read_unlock();
1900                 if (!src->data) {
1901                         if (src_entry->preferred_base) {
1902                                 static int warned = 0;
1903                                 if (!warned++)
1904                                         warning("object %s cannot be read",
1905                                                 oid_to_hex(&src_entry->idx.oid));
1906                                 /*
1907                                  * Those objects are not included in the
1908                                  * resulting pack.  Be resilient and ignore
1909                                  * them if they can't be read, in case the
1910                                  * pack could be created nevertheless.
1911                                  */
1912                                 return 0;
1913                         }
1914                         die("object %s cannot be read",
1915                             oid_to_hex(&src_entry->idx.oid));
1916                 }
1917                 if (sz != src_size)
1918                         die("object %s inconsistent object length (%lu vs %lu)",
1919                             oid_to_hex(&src_entry->idx.oid), sz,
1920                             src_size);
1921                 *mem_usage += sz;
1922         }
1923         if (!src->index) {
1924                 src->index = create_delta_index(src->data, src_size);
1925                 if (!src->index) {
1926                         static int warned = 0;
1927                         if (!warned++)
1928                                 warning("suboptimal pack - out of memory");
1929                         return 0;
1930                 }
1931                 *mem_usage += sizeof_delta_index(src->index);
1932         }
1933
1934         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1935         if (!delta_buf)
1936                 return 0;
1937
1938         if (trg_entry->delta) {
1939                 /* Prefer only shallower same-sized deltas. */
1940                 if (delta_size == trg_entry->delta_size &&
1941                     src->depth + 1 >= trg->depth) {
1942                         free(delta_buf);
1943                         return 0;
1944                 }
1945         }
1946
1947         /*
1948          * Handle memory allocation outside of the cache
1949          * accounting lock.  Compiler will optimize the strangeness
1950          * away when NO_PTHREADS is defined.
1951          */
1952         free(trg_entry->delta_data);
1953         cache_lock();
1954         if (trg_entry->delta_data) {
1955                 delta_cache_size -= trg_entry->delta_size;
1956                 trg_entry->delta_data = NULL;
1957         }
1958         if (delta_cacheable(src_size, trg_size, delta_size)) {
1959                 delta_cache_size += delta_size;
1960                 cache_unlock();
1961                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1962         } else {
1963                 cache_unlock();
1964                 free(delta_buf);
1965         }
1966
1967         trg_entry->delta = src_entry;
1968         trg_entry->delta_size = delta_size;
1969         trg->depth = src->depth + 1;
1970
1971         return 1;
1972 }
1973
1974 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1975 {
1976         struct object_entry *child = me->delta_child;
1977         unsigned int m = n;
1978         while (child) {
1979                 unsigned int c = check_delta_limit(child, n + 1);
1980                 if (m < c)
1981                         m = c;
1982                 child = child->delta_sibling;
1983         }
1984         return m;
1985 }
1986
1987 static unsigned long free_unpacked(struct unpacked *n)
1988 {
1989         unsigned long freed_mem = sizeof_delta_index(n->index);
1990         free_delta_index(n->index);
1991         n->index = NULL;
1992         if (n->data) {
1993                 freed_mem += n->entry->size;
1994                 FREE_AND_NULL(n->data);
1995         }
1996         n->entry = NULL;
1997         n->depth = 0;
1998         return freed_mem;
1999 }
2000
2001 static void find_deltas(struct object_entry **list, unsigned *list_size,
2002                         int window, int depth, unsigned *processed)
2003 {
2004         uint32_t i, idx = 0, count = 0;
2005         struct unpacked *array;
2006         unsigned long mem_usage = 0;
2007
2008         array = xcalloc(window, sizeof(struct unpacked));
2009
2010         for (;;) {
2011                 struct object_entry *entry;
2012                 struct unpacked *n = array + idx;
2013                 int j, max_depth, best_base = -1;
2014
2015                 progress_lock();
2016                 if (!*list_size) {
2017                         progress_unlock();
2018                         break;
2019                 }
2020                 entry = *list++;
2021                 (*list_size)--;
2022                 if (!entry->preferred_base) {
2023                         (*processed)++;
2024                         display_progress(progress_state, *processed);
2025                 }
2026                 progress_unlock();
2027
2028                 mem_usage -= free_unpacked(n);
2029                 n->entry = entry;
2030
2031                 while (window_memory_limit &&
2032                        mem_usage > window_memory_limit &&
2033                        count > 1) {
2034                         uint32_t tail = (idx + window - count) % window;
2035                         mem_usage -= free_unpacked(array + tail);
2036                         count--;
2037                 }
2038
2039                 /* We do not compute delta to *create* objects we are not
2040                  * going to pack.
2041                  */
2042                 if (entry->preferred_base)
2043                         goto next;
2044
2045                 /*
2046                  * If the current object is at pack edge, take the depth the
2047                  * objects that depend on the current object into account
2048                  * otherwise they would become too deep.
2049                  */
2050                 max_depth = depth;
2051                 if (entry->delta_child) {
2052                         max_depth -= check_delta_limit(entry, 0);
2053                         if (max_depth <= 0)
2054                                 goto next;
2055                 }
2056
2057                 j = window;
2058                 while (--j > 0) {
2059                         int ret;
2060                         uint32_t other_idx = idx + j;
2061                         struct unpacked *m;
2062                         if (other_idx >= window)
2063                                 other_idx -= window;
2064                         m = array + other_idx;
2065                         if (!m->entry)
2066                                 break;
2067                         ret = try_delta(n, m, max_depth, &mem_usage);
2068                         if (ret < 0)
2069                                 break;
2070                         else if (ret > 0)
2071                                 best_base = other_idx;
2072                 }
2073
2074                 /*
2075                  * If we decided to cache the delta data, then it is best
2076                  * to compress it right away.  First because we have to do
2077                  * it anyway, and doing it here while we're threaded will
2078                  * save a lot of time in the non threaded write phase,
2079                  * as well as allow for caching more deltas within
2080                  * the same cache size limit.
2081                  * ...
2082                  * But only if not writing to stdout, since in that case
2083                  * the network is most likely throttling writes anyway,
2084                  * and therefore it is best to go to the write phase ASAP
2085                  * instead, as we can afford spending more time compressing
2086                  * between writes at that moment.
2087                  */
2088                 if (entry->delta_data && !pack_to_stdout) {
2089                         entry->z_delta_size = do_compress(&entry->delta_data,
2090                                                           entry->delta_size);
2091                         cache_lock();
2092                         delta_cache_size -= entry->delta_size;
2093                         delta_cache_size += entry->z_delta_size;
2094                         cache_unlock();
2095                 }
2096
2097                 /* if we made n a delta, and if n is already at max
2098                  * depth, leaving it in the window is pointless.  we
2099                  * should evict it first.
2100                  */
2101                 if (entry->delta && max_depth <= n->depth)
2102                         continue;
2103
2104                 /*
2105                  * Move the best delta base up in the window, after the
2106                  * currently deltified object, to keep it longer.  It will
2107                  * be the first base object to be attempted next.
2108                  */
2109                 if (entry->delta) {
2110                         struct unpacked swap = array[best_base];
2111                         int dist = (window + idx - best_base) % window;
2112                         int dst = best_base;
2113                         while (dist--) {
2114                                 int src = (dst + 1) % window;
2115                                 array[dst] = array[src];
2116                                 dst = src;
2117                         }
2118                         array[dst] = swap;
2119                 }
2120
2121                 next:
2122                 idx++;
2123                 if (count + 1 < window)
2124                         count++;
2125                 if (idx >= window)
2126                         idx = 0;
2127         }
2128
2129         for (i = 0; i < window; ++i) {
2130                 free_delta_index(array[i].index);
2131                 free(array[i].data);
2132         }
2133         free(array);
2134 }
2135
2136 #ifndef NO_PTHREADS
2137
2138 static void try_to_free_from_threads(size_t size)
2139 {
2140         read_lock();
2141         release_pack_memory(size);
2142         read_unlock();
2143 }
2144
2145 static try_to_free_t old_try_to_free_routine;
2146
2147 /*
2148  * The main thread waits on the condition that (at least) one of the workers
2149  * has stopped working (which is indicated in the .working member of
2150  * struct thread_params).
2151  * When a work thread has completed its work, it sets .working to 0 and
2152  * signals the main thread and waits on the condition that .data_ready
2153  * becomes 1.
2154  */
2155
2156 struct thread_params {
2157         pthread_t thread;
2158         struct object_entry **list;
2159         unsigned list_size;
2160         unsigned remaining;
2161         int window;
2162         int depth;
2163         int working;
2164         int data_ready;
2165         pthread_mutex_t mutex;
2166         pthread_cond_t cond;
2167         unsigned *processed;
2168 };
2169
2170 static pthread_cond_t progress_cond;
2171
2172 /*
2173  * Mutex and conditional variable can't be statically-initialized on Windows.
2174  */
2175 static void init_threaded_search(void)
2176 {
2177         init_recursive_mutex(&read_mutex);
2178         pthread_mutex_init(&cache_mutex, NULL);
2179         pthread_mutex_init(&progress_mutex, NULL);
2180         pthread_cond_init(&progress_cond, NULL);
2181         old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
2182 }
2183
2184 static void cleanup_threaded_search(void)
2185 {
2186         set_try_to_free_routine(old_try_to_free_routine);
2187         pthread_cond_destroy(&progress_cond);
2188         pthread_mutex_destroy(&read_mutex);
2189         pthread_mutex_destroy(&cache_mutex);
2190         pthread_mutex_destroy(&progress_mutex);
2191 }
2192
2193 static void *threaded_find_deltas(void *arg)
2194 {
2195         struct thread_params *me = arg;
2196
2197         progress_lock();
2198         while (me->remaining) {
2199                 progress_unlock();
2200
2201                 find_deltas(me->list, &me->remaining,
2202                             me->window, me->depth, me->processed);
2203
2204                 progress_lock();
2205                 me->working = 0;
2206                 pthread_cond_signal(&progress_cond);
2207                 progress_unlock();
2208
2209                 /*
2210                  * We must not set ->data_ready before we wait on the
2211                  * condition because the main thread may have set it to 1
2212                  * before we get here. In order to be sure that new
2213                  * work is available if we see 1 in ->data_ready, it
2214                  * was initialized to 0 before this thread was spawned
2215                  * and we reset it to 0 right away.
2216                  */
2217                 pthread_mutex_lock(&me->mutex);
2218                 while (!me->data_ready)
2219                         pthread_cond_wait(&me->cond, &me->mutex);
2220                 me->data_ready = 0;
2221                 pthread_mutex_unlock(&me->mutex);
2222
2223                 progress_lock();
2224         }
2225         progress_unlock();
2226         /* leave ->working 1 so that this doesn't get more work assigned */
2227         return NULL;
2228 }
2229
2230 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
2231                            int window, int depth, unsigned *processed)
2232 {
2233         struct thread_params *p;
2234         int i, ret, active_threads = 0;
2235
2236         init_threaded_search();
2237
2238         if (delta_search_threads <= 1) {
2239                 find_deltas(list, &list_size, window, depth, processed);
2240                 cleanup_threaded_search();
2241                 return;
2242         }
2243         if (progress > pack_to_stdout)
2244                 fprintf(stderr, "Delta compression using up to %d threads.\n",
2245                                 delta_search_threads);
2246         p = xcalloc(delta_search_threads, sizeof(*p));
2247
2248         /* Partition the work amongst work threads. */
2249         for (i = 0; i < delta_search_threads; i++) {
2250                 unsigned sub_size = list_size / (delta_search_threads - i);
2251
2252                 /* don't use too small segments or no deltas will be found */
2253                 if (sub_size < 2*window && i+1 < delta_search_threads)
2254                         sub_size = 0;
2255
2256                 p[i].window = window;
2257                 p[i].depth = depth;
2258                 p[i].processed = processed;
2259                 p[i].working = 1;
2260                 p[i].data_ready = 0;
2261
2262                 /* try to split chunks on "path" boundaries */
2263                 while (sub_size && sub_size < list_size &&
2264                        list[sub_size]->hash &&
2265                        list[sub_size]->hash == list[sub_size-1]->hash)
2266                         sub_size++;
2267
2268                 p[i].list = list;
2269                 p[i].list_size = sub_size;
2270                 p[i].remaining = sub_size;
2271
2272                 list += sub_size;
2273                 list_size -= sub_size;
2274         }
2275
2276         /* Start work threads. */
2277         for (i = 0; i < delta_search_threads; i++) {
2278                 if (!p[i].list_size)
2279                         continue;
2280                 pthread_mutex_init(&p[i].mutex, NULL);
2281                 pthread_cond_init(&p[i].cond, NULL);
2282                 ret = pthread_create(&p[i].thread, NULL,
2283                                      threaded_find_deltas, &p[i]);
2284                 if (ret)
2285                         die("unable to create thread: %s", strerror(ret));
2286                 active_threads++;
2287         }
2288
2289         /*
2290          * Now let's wait for work completion.  Each time a thread is done
2291          * with its work, we steal half of the remaining work from the
2292          * thread with the largest number of unprocessed objects and give
2293          * it to that newly idle thread.  This ensure good load balancing
2294          * until the remaining object list segments are simply too short
2295          * to be worth splitting anymore.
2296          */
2297         while (active_threads) {
2298                 struct thread_params *target = NULL;
2299                 struct thread_params *victim = NULL;
2300                 unsigned sub_size = 0;
2301
2302                 progress_lock();
2303                 for (;;) {
2304                         for (i = 0; !target && i < delta_search_threads; i++)
2305                                 if (!p[i].working)
2306                                         target = &p[i];
2307                         if (target)
2308                                 break;
2309                         pthread_cond_wait(&progress_cond, &progress_mutex);
2310                 }
2311
2312                 for (i = 0; i < delta_search_threads; i++)
2313                         if (p[i].remaining > 2*window &&
2314                             (!victim || victim->remaining < p[i].remaining))
2315                                 victim = &p[i];
2316                 if (victim) {
2317                         sub_size = victim->remaining / 2;
2318                         list = victim->list + victim->list_size - sub_size;
2319                         while (sub_size && list[0]->hash &&
2320                                list[0]->hash == list[-1]->hash) {
2321                                 list++;
2322                                 sub_size--;
2323                         }
2324                         if (!sub_size) {
2325                                 /*
2326                                  * It is possible for some "paths" to have
2327                                  * so many objects that no hash boundary
2328                                  * might be found.  Let's just steal the
2329                                  * exact half in that case.
2330                                  */
2331                                 sub_size = victim->remaining / 2;
2332                                 list -= sub_size;
2333                         }
2334                         target->list = list;
2335                         victim->list_size -= sub_size;
2336                         victim->remaining -= sub_size;
2337                 }
2338                 target->list_size = sub_size;
2339                 target->remaining = sub_size;
2340                 target->working = 1;
2341                 progress_unlock();
2342
2343                 pthread_mutex_lock(&target->mutex);
2344                 target->data_ready = 1;
2345                 pthread_cond_signal(&target->cond);
2346                 pthread_mutex_unlock(&target->mutex);
2347
2348                 if (!sub_size) {
2349                         pthread_join(target->thread, NULL);
2350                         pthread_cond_destroy(&target->cond);
2351                         pthread_mutex_destroy(&target->mutex);
2352                         active_threads--;
2353                 }
2354         }
2355         cleanup_threaded_search();
2356         free(p);
2357 }
2358
2359 #else
2360 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
2361 #endif
2362
2363 static void add_tag_chain(const struct object_id *oid)
2364 {
2365         struct tag *tag;
2366
2367         /*
2368          * We catch duplicates already in add_object_entry(), but we'd
2369          * prefer to do this extra check to avoid having to parse the
2370          * tag at all if we already know that it's being packed (e.g., if
2371          * it was included via bitmaps, we would not have parsed it
2372          * previously).
2373          */
2374         if (packlist_find(&to_pack, oid->hash, NULL))
2375                 return;
2376
2377         tag = lookup_tag(oid);
2378         while (1) {
2379                 if (!tag || parse_tag(tag) || !tag->tagged)
2380                         die("unable to pack objects reachable from tag %s",
2381                             oid_to_hex(oid));
2382
2383                 add_object_entry(&tag->object.oid, OBJ_TAG, NULL, 0);
2384
2385                 if (tag->tagged->type != OBJ_TAG)
2386                         return;
2387
2388                 tag = (struct tag *)tag->tagged;
2389         }
2390 }
2391
2392 static int add_ref_tag(const char *path, const struct object_id *oid, int flag, void *cb_data)
2393 {
2394         struct object_id peeled;
2395
2396         if (starts_with(path, "refs/tags/") && /* is a tag? */
2397             !peel_ref(path, &peeled)    && /* peelable? */
2398             packlist_find(&to_pack, peeled.hash, NULL))      /* object packed? */
2399                 add_tag_chain(oid);
2400         return 0;
2401 }
2402
2403 static void prepare_pack(int window, int depth)
2404 {
2405         struct object_entry **delta_list;
2406         uint32_t i, nr_deltas;
2407         unsigned n;
2408
2409         get_object_details();
2410
2411         /*
2412          * If we're locally repacking then we need to be doubly careful
2413          * from now on in order to make sure no stealth corruption gets
2414          * propagated to the new pack.  Clients receiving streamed packs
2415          * should validate everything they get anyway so no need to incur
2416          * the additional cost here in that case.
2417          */
2418         if (!pack_to_stdout)
2419                 do_check_packed_object_crc = 1;
2420
2421         if (!to_pack.nr_objects || !window || !depth)
2422                 return;
2423
2424         ALLOC_ARRAY(delta_list, to_pack.nr_objects);
2425         nr_deltas = n = 0;
2426
2427         for (i = 0; i < to_pack.nr_objects; i++) {
2428                 struct object_entry *entry = to_pack.objects + i;
2429
2430                 if (entry->delta)
2431                         /* This happens if we decided to reuse existing
2432                          * delta from a pack.  "reuse_delta &&" is implied.
2433                          */
2434                         continue;
2435
2436                 if (entry->size < 50)
2437                         continue;
2438
2439                 if (entry->no_try_delta)
2440                         continue;
2441
2442                 if (!entry->preferred_base) {
2443                         nr_deltas++;
2444                         if (oe_type(entry) < 0)
2445                                 die("unable to get type of object %s",
2446                                     oid_to_hex(&entry->idx.oid));
2447                 } else {
2448                         if (oe_type(entry) < 0) {
2449                                 /*
2450                                  * This object is not found, but we
2451                                  * don't have to include it anyway.
2452                                  */
2453                                 continue;
2454                         }
2455                 }
2456
2457                 delta_list[n++] = entry;
2458         }
2459
2460         if (nr_deltas && n > 1) {
2461                 unsigned nr_done = 0;
2462                 if (progress)
2463                         progress_state = start_progress(_("Compressing objects"),
2464                                                         nr_deltas);
2465                 QSORT(delta_list, n, type_size_sort);
2466                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2467                 stop_progress(&progress_state);
2468                 if (nr_done != nr_deltas)
2469                         die("inconsistency with delta count");
2470         }
2471         free(delta_list);
2472 }
2473
2474 static int git_pack_config(const char *k, const char *v, void *cb)
2475 {
2476         if (!strcmp(k, "pack.window")) {
2477                 window = git_config_int(k, v);
2478                 return 0;
2479         }
2480         if (!strcmp(k, "pack.windowmemory")) {
2481                 window_memory_limit = git_config_ulong(k, v);
2482                 return 0;
2483         }
2484         if (!strcmp(k, "pack.depth")) {
2485                 depth = git_config_int(k, v);
2486                 return 0;
2487         }
2488         if (!strcmp(k, "pack.deltacachesize")) {
2489                 max_delta_cache_size = git_config_int(k, v);
2490                 return 0;
2491         }
2492         if (!strcmp(k, "pack.deltacachelimit")) {
2493                 cache_max_small_delta_size = git_config_int(k, v);
2494                 return 0;
2495         }
2496         if (!strcmp(k, "pack.writebitmaphashcache")) {
2497                 if (git_config_bool(k, v))
2498                         write_bitmap_options |= BITMAP_OPT_HASH_CACHE;
2499                 else
2500                         write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
2501         }
2502         if (!strcmp(k, "pack.usebitmaps")) {
2503                 use_bitmap_index_default = git_config_bool(k, v);
2504                 return 0;
2505         }
2506         if (!strcmp(k, "pack.threads")) {
2507                 delta_search_threads = git_config_int(k, v);
2508                 if (delta_search_threads < 0)
2509                         die("invalid number of threads specified (%d)",
2510                             delta_search_threads);
2511 #ifdef NO_PTHREADS
2512                 if (delta_search_threads != 1) {
2513                         warning("no threads support, ignoring %s", k);
2514                         delta_search_threads = 0;
2515                 }
2516 #endif
2517                 return 0;
2518         }
2519         if (!strcmp(k, "pack.indexversion")) {
2520                 pack_idx_opts.version = git_config_int(k, v);
2521                 if (pack_idx_opts.version > 2)
2522                         die("bad pack.indexversion=%"PRIu32,
2523                             pack_idx_opts.version);
2524                 return 0;
2525         }
2526         return git_default_config(k, v, cb);
2527 }
2528
2529 static void read_object_list_from_stdin(void)
2530 {
2531         char line[GIT_MAX_HEXSZ + 1 + PATH_MAX + 2];
2532         struct object_id oid;
2533         const char *p;
2534
2535         for (;;) {
2536                 if (!fgets(line, sizeof(line), stdin)) {
2537                         if (feof(stdin))
2538                                 break;
2539                         if (!ferror(stdin))
2540                                 die("fgets returned NULL, not EOF, not error!");
2541                         if (errno != EINTR)
2542                                 die_errno("fgets");
2543                         clearerr(stdin);
2544                         continue;
2545                 }
2546                 if (line[0] == '-') {
2547                         if (get_oid_hex(line+1, &oid))
2548                                 die("expected edge object ID, got garbage:\n %s",
2549                                     line);
2550                         add_preferred_base(&oid);
2551                         continue;
2552                 }
2553                 if (parse_oid_hex(line, &oid, &p))
2554                         die("expected object ID, got garbage:\n %s", line);
2555
2556                 add_preferred_base_object(p + 1);
2557                 add_object_entry(&oid, OBJ_NONE, p + 1, 0);
2558         }
2559 }
2560
2561 /* Remember to update object flag allocation in object.h */
2562 #define OBJECT_ADDED (1u<<20)
2563
2564 static void show_commit(struct commit *commit, void *data)
2565 {
2566         add_object_entry(&commit->object.oid, OBJ_COMMIT, NULL, 0);
2567         commit->object.flags |= OBJECT_ADDED;
2568
2569         if (write_bitmap_index)
2570                 index_commit_for_bitmap(commit);
2571 }
2572
2573 static void show_object(struct object *obj, const char *name, void *data)
2574 {
2575         add_preferred_base_object(name);
2576         add_object_entry(&obj->oid, obj->type, name, 0);
2577         obj->flags |= OBJECT_ADDED;
2578 }
2579
2580 static void show_object__ma_allow_any(struct object *obj, const char *name, void *data)
2581 {
2582         assert(arg_missing_action == MA_ALLOW_ANY);
2583
2584         /*
2585          * Quietly ignore ALL missing objects.  This avoids problems with
2586          * staging them now and getting an odd error later.
2587          */
2588         if (!has_object_file(&obj->oid))
2589                 return;
2590
2591         show_object(obj, name, data);
2592 }
2593
2594 static void show_object__ma_allow_promisor(struct object *obj, const char *name, void *data)
2595 {
2596         assert(arg_missing_action == MA_ALLOW_PROMISOR);
2597
2598         /*
2599          * Quietly ignore EXPECTED missing objects.  This avoids problems with
2600          * staging them now and getting an odd error later.
2601          */
2602         if (!has_object_file(&obj->oid) && is_promisor_object(&obj->oid))
2603                 return;
2604
2605         show_object(obj, name, data);
2606 }
2607
2608 static int option_parse_missing_action(const struct option *opt,
2609                                        const char *arg, int unset)
2610 {
2611         assert(arg);
2612         assert(!unset);
2613
2614         if (!strcmp(arg, "error")) {
2615                 arg_missing_action = MA_ERROR;
2616                 fn_show_object = show_object;
2617                 return 0;
2618         }
2619
2620         if (!strcmp(arg, "allow-any")) {
2621                 arg_missing_action = MA_ALLOW_ANY;
2622                 fetch_if_missing = 0;
2623                 fn_show_object = show_object__ma_allow_any;
2624                 return 0;
2625         }
2626
2627         if (!strcmp(arg, "allow-promisor")) {
2628                 arg_missing_action = MA_ALLOW_PROMISOR;
2629                 fetch_if_missing = 0;
2630                 fn_show_object = show_object__ma_allow_promisor;
2631                 return 0;
2632         }
2633
2634         die(_("invalid value for --missing"));
2635         return 0;
2636 }
2637
2638 static void show_edge(struct commit *commit)
2639 {
2640         add_preferred_base(&commit->object.oid);
2641 }
2642
2643 struct in_pack_object {
2644         off_t offset;
2645         struct object *object;
2646 };
2647
2648 struct in_pack {
2649         unsigned int alloc;
2650         unsigned int nr;
2651         struct in_pack_object *array;
2652 };
2653
2654 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2655 {
2656         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->oid.hash, p);
2657         in_pack->array[in_pack->nr].object = object;
2658         in_pack->nr++;
2659 }
2660
2661 /*
2662  * Compare the objects in the offset order, in order to emulate the
2663  * "git rev-list --objects" output that produced the pack originally.
2664  */
2665 static int ofscmp(const void *a_, const void *b_)
2666 {
2667         struct in_pack_object *a = (struct in_pack_object *)a_;
2668         struct in_pack_object *b = (struct in_pack_object *)b_;
2669
2670         if (a->offset < b->offset)
2671                 return -1;
2672         else if (a->offset > b->offset)
2673                 return 1;
2674         else
2675                 return oidcmp(&a->object->oid, &b->object->oid);
2676 }
2677
2678 static void add_objects_in_unpacked_packs(struct rev_info *revs)
2679 {
2680         struct packed_git *p;
2681         struct in_pack in_pack;
2682         uint32_t i;
2683
2684         memset(&in_pack, 0, sizeof(in_pack));
2685
2686         for (p = get_packed_git(the_repository); p; p = p->next) {
2687                 struct object_id oid;
2688                 struct object *o;
2689
2690                 if (!p->pack_local || p->pack_keep)
2691                         continue;
2692                 if (open_pack_index(p))
2693                         die("cannot open pack index");
2694
2695                 ALLOC_GROW(in_pack.array,
2696                            in_pack.nr + p->num_objects,
2697                            in_pack.alloc);
2698
2699                 for (i = 0; i < p->num_objects; i++) {
2700                         nth_packed_object_oid(&oid, p, i);
2701                         o = lookup_unknown_object(oid.hash);
2702                         if (!(o->flags & OBJECT_ADDED))
2703                                 mark_in_pack_object(o, p, &in_pack);
2704                         o->flags |= OBJECT_ADDED;
2705                 }
2706         }
2707
2708         if (in_pack.nr) {
2709                 QSORT(in_pack.array, in_pack.nr, ofscmp);
2710                 for (i = 0; i < in_pack.nr; i++) {
2711                         struct object *o = in_pack.array[i].object;
2712                         add_object_entry(&o->oid, o->type, "", 0);
2713                 }
2714         }
2715         free(in_pack.array);
2716 }
2717
2718 static int add_loose_object(const struct object_id *oid, const char *path,
2719                             void *data)
2720 {
2721         enum object_type type = oid_object_info(oid, NULL);
2722
2723         if (type < 0) {
2724                 warning("loose object at %s could not be examined", path);
2725                 return 0;
2726         }
2727
2728         add_object_entry(oid, type, "", 0);
2729         return 0;
2730 }
2731
2732 /*
2733  * We actually don't even have to worry about reachability here.
2734  * add_object_entry will weed out duplicates, so we just add every
2735  * loose object we find.
2736  */
2737 static void add_unreachable_loose_objects(void)
2738 {
2739         for_each_loose_file_in_objdir(get_object_directory(),
2740                                       add_loose_object,
2741                                       NULL, NULL, NULL);
2742 }
2743
2744 static int has_sha1_pack_kept_or_nonlocal(const struct object_id *oid)
2745 {
2746         static struct packed_git *last_found = (void *)1;
2747         struct packed_git *p;
2748
2749         p = (last_found != (void *)1) ? last_found :
2750                                         get_packed_git(the_repository);
2751
2752         while (p) {
2753                 if ((!p->pack_local || p->pack_keep) &&
2754                         find_pack_entry_one(oid->hash, p)) {
2755                         last_found = p;
2756                         return 1;
2757                 }
2758                 if (p == last_found)
2759                         p = get_packed_git(the_repository);
2760                 else
2761                         p = p->next;
2762                 if (p == last_found)
2763                         p = p->next;
2764         }
2765         return 0;
2766 }
2767
2768 /*
2769  * Store a list of sha1s that are should not be discarded
2770  * because they are either written too recently, or are
2771  * reachable from another object that was.
2772  *
2773  * This is filled by get_object_list.
2774  */
2775 static struct oid_array recent_objects;
2776
2777 static int loosened_object_can_be_discarded(const struct object_id *oid,
2778                                             timestamp_t mtime)
2779 {
2780         if (!unpack_unreachable_expiration)
2781                 return 0;
2782         if (mtime > unpack_unreachable_expiration)
2783                 return 0;
2784         if (oid_array_lookup(&recent_objects, oid) >= 0)
2785                 return 0;
2786         return 1;
2787 }
2788
2789 static void loosen_unused_packed_objects(struct rev_info *revs)
2790 {
2791         struct packed_git *p;
2792         uint32_t i;
2793         struct object_id oid;
2794
2795         for (p = get_packed_git(the_repository); p; p = p->next) {
2796                 if (!p->pack_local || p->pack_keep)
2797                         continue;
2798
2799                 if (open_pack_index(p))
2800                         die("cannot open pack index");
2801
2802                 for (i = 0; i < p->num_objects; i++) {
2803                         nth_packed_object_oid(&oid, p, i);
2804                         if (!packlist_find(&to_pack, oid.hash, NULL) &&
2805                             !has_sha1_pack_kept_or_nonlocal(&oid) &&
2806                             !loosened_object_can_be_discarded(&oid, p->mtime))
2807                                 if (force_object_loose(&oid, p->mtime))
2808                                         die("unable to force loose object");
2809                 }
2810         }
2811 }
2812
2813 /*
2814  * This tracks any options which pack-reuse code expects to be on, or which a
2815  * reader of the pack might not understand, and which would therefore prevent
2816  * blind reuse of what we have on disk.
2817  */
2818 static int pack_options_allow_reuse(void)
2819 {
2820         return pack_to_stdout &&
2821                allow_ofs_delta &&
2822                !ignore_packed_keep &&
2823                (!local || !have_non_local_packs) &&
2824                !incremental;
2825 }
2826
2827 static int get_object_list_from_bitmap(struct rev_info *revs)
2828 {
2829         if (prepare_bitmap_walk(revs) < 0)
2830                 return -1;
2831
2832         if (pack_options_allow_reuse() &&
2833             !reuse_partial_packfile_from_bitmap(
2834                         &reuse_packfile,
2835                         &reuse_packfile_objects,
2836                         &reuse_packfile_offset)) {
2837                 assert(reuse_packfile_objects);
2838                 nr_result += reuse_packfile_objects;
2839                 display_progress(progress_state, nr_result);
2840         }
2841
2842         traverse_bitmap_commit_list(&add_object_entry_from_bitmap);
2843         return 0;
2844 }
2845
2846 static void record_recent_object(struct object *obj,
2847                                  const char *name,
2848                                  void *data)
2849 {
2850         oid_array_append(&recent_objects, &obj->oid);
2851 }
2852
2853 static void record_recent_commit(struct commit *commit, void *data)
2854 {
2855         oid_array_append(&recent_objects, &commit->object.oid);
2856 }
2857
2858 static void get_object_list(int ac, const char **av)
2859 {
2860         struct rev_info revs;
2861         char line[1000];
2862         int flags = 0;
2863
2864         init_revisions(&revs, NULL);
2865         save_commit_buffer = 0;
2866         setup_revisions(ac, av, &revs, NULL);
2867
2868         /* make sure shallows are read */
2869         is_repository_shallow();
2870
2871         while (fgets(line, sizeof(line), stdin) != NULL) {
2872                 int len = strlen(line);
2873                 if (len && line[len - 1] == '\n')
2874                         line[--len] = 0;
2875                 if (!len)
2876                         break;
2877                 if (*line == '-') {
2878                         if (!strcmp(line, "--not")) {
2879                                 flags ^= UNINTERESTING;
2880                                 write_bitmap_index = 0;
2881                                 continue;
2882                         }
2883                         if (starts_with(line, "--shallow ")) {
2884                                 struct object_id oid;
2885                                 if (get_oid_hex(line + 10, &oid))
2886                                         die("not an SHA-1 '%s'", line + 10);
2887                                 register_shallow(&oid);
2888                                 use_bitmap_index = 0;
2889                                 continue;
2890                         }
2891                         die("not a rev '%s'", line);
2892                 }
2893                 if (handle_revision_arg(line, &revs, flags, REVARG_CANNOT_BE_FILENAME))
2894                         die("bad revision '%s'", line);
2895         }
2896
2897         if (use_bitmap_index && !get_object_list_from_bitmap(&revs))
2898                 return;
2899
2900         if (prepare_revision_walk(&revs))
2901                 die("revision walk setup failed");
2902         mark_edges_uninteresting(&revs, show_edge);
2903
2904         if (!fn_show_object)
2905                 fn_show_object = show_object;
2906         traverse_commit_list_filtered(&filter_options, &revs,
2907                                       show_commit, fn_show_object, NULL,
2908                                       NULL);
2909
2910         if (unpack_unreachable_expiration) {
2911                 revs.ignore_missing_links = 1;
2912                 if (add_unseen_recent_objects_to_traversal(&revs,
2913                                 unpack_unreachable_expiration))
2914                         die("unable to add recent objects");
2915                 if (prepare_revision_walk(&revs))
2916                         die("revision walk setup failed");
2917                 traverse_commit_list(&revs, record_recent_commit,
2918                                      record_recent_object, NULL);
2919         }
2920
2921         if (keep_unreachable)
2922                 add_objects_in_unpacked_packs(&revs);
2923         if (pack_loose_unreachable)
2924                 add_unreachable_loose_objects();
2925         if (unpack_unreachable)
2926                 loosen_unused_packed_objects(&revs);
2927
2928         oid_array_clear(&recent_objects);
2929 }
2930
2931 static int option_parse_index_version(const struct option *opt,
2932                                       const char *arg, int unset)
2933 {
2934         char *c;
2935         const char *val = arg;
2936         pack_idx_opts.version = strtoul(val, &c, 10);
2937         if (pack_idx_opts.version > 2)
2938                 die(_("unsupported index version %s"), val);
2939         if (*c == ',' && c[1])
2940                 pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2941         if (*c || pack_idx_opts.off32_limit & 0x80000000)
2942                 die(_("bad index version '%s'"), val);
2943         return 0;
2944 }
2945
2946 static int option_parse_unpack_unreachable(const struct option *opt,
2947                                            const char *arg, int unset)
2948 {
2949         if (unset) {
2950                 unpack_unreachable = 0;
2951                 unpack_unreachable_expiration = 0;
2952         }
2953         else {
2954                 unpack_unreachable = 1;
2955                 if (arg)
2956                         unpack_unreachable_expiration = approxidate(arg);
2957         }
2958         return 0;
2959 }
2960
2961 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2962 {
2963         int use_internal_rev_list = 0;
2964         int thin = 0;
2965         int shallow = 0;
2966         int all_progress_implied = 0;
2967         struct argv_array rp = ARGV_ARRAY_INIT;
2968         int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
2969         int rev_list_index = 0;
2970         struct option pack_objects_options[] = {
2971                 OPT_SET_INT('q', "quiet", &progress,
2972                             N_("do not show progress meter"), 0),
2973                 OPT_SET_INT(0, "progress", &progress,
2974                             N_("show progress meter"), 1),
2975                 OPT_SET_INT(0, "all-progress", &progress,
2976                             N_("show progress meter during object writing phase"), 2),
2977                 OPT_BOOL(0, "all-progress-implied",
2978                          &all_progress_implied,
2979                          N_("similar to --all-progress when progress meter is shown")),
2980                 { OPTION_CALLBACK, 0, "index-version", NULL, N_("version[,offset]"),
2981                   N_("write the pack index file in the specified idx format version"),
2982                   0, option_parse_index_version },
2983                 OPT_MAGNITUDE(0, "max-pack-size", &pack_size_limit,
2984                               N_("maximum size of each output pack file")),
2985                 OPT_BOOL(0, "local", &local,
2986                          N_("ignore borrowed objects from alternate object store")),
2987                 OPT_BOOL(0, "incremental", &incremental,
2988                          N_("ignore packed objects")),
2989                 OPT_INTEGER(0, "window", &window,
2990                             N_("limit pack window by objects")),
2991                 OPT_MAGNITUDE(0, "window-memory", &window_memory_limit,
2992                               N_("limit pack window by memory in addition to object limit")),
2993                 OPT_INTEGER(0, "depth", &depth,
2994                             N_("maximum length of delta chain allowed in the resulting pack")),
2995                 OPT_BOOL(0, "reuse-delta", &reuse_delta,
2996                          N_("reuse existing deltas")),
2997                 OPT_BOOL(0, "reuse-object", &reuse_object,
2998                          N_("reuse existing objects")),
2999                 OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
3000                          N_("use OFS_DELTA objects")),
3001                 OPT_INTEGER(0, "threads", &delta_search_threads,
3002                             N_("use threads when searching for best delta matches")),
3003                 OPT_BOOL(0, "non-empty", &non_empty,
3004                          N_("do not create an empty pack output")),
3005                 OPT_BOOL(0, "revs", &use_internal_rev_list,
3006                          N_("read revision arguments from standard input")),
3007                 { OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
3008                   N_("limit the objects to those that are not yet packed"),
3009                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3010                 { OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
3011                   N_("include objects reachable from any reference"),
3012                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3013                 { OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
3014                   N_("include objects referred by reflog entries"),
3015                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3016                 { OPTION_SET_INT, 0, "indexed-objects", &rev_list_index, NULL,
3017                   N_("include objects referred to by the index"),
3018                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
3019                 OPT_BOOL(0, "stdout", &pack_to_stdout,
3020                          N_("output pack to stdout")),
3021                 OPT_BOOL(0, "include-tag", &include_tag,
3022                          N_("include tag objects that refer to objects to be packed")),
3023                 OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
3024                          N_("keep unreachable objects")),
3025                 OPT_BOOL(0, "pack-loose-unreachable", &pack_loose_unreachable,
3026                          N_("pack loose unreachable objects")),
3027                 { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, N_("time"),
3028                   N_("unpack unreachable objects newer than <time>"),
3029                   PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
3030                 OPT_BOOL(0, "thin", &thin,
3031                          N_("create thin packs")),
3032                 OPT_BOOL(0, "shallow", &shallow,
3033                          N_("create packs suitable for shallow fetches")),
3034                 OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
3035                          N_("ignore packs that have companion .keep file")),
3036                 OPT_INTEGER(0, "compression", &pack_compression_level,
3037                             N_("pack compression level")),
3038                 OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
3039                             N_("do not hide commits by grafts"), 0),
3040                 OPT_BOOL(0, "use-bitmap-index", &use_bitmap_index,
3041                          N_("use a bitmap index if available to speed up counting objects")),
3042                 OPT_BOOL(0, "write-bitmap-index", &write_bitmap_index,
3043                          N_("write a bitmap index together with the pack index")),
3044                 OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
3045                 { OPTION_CALLBACK, 0, "missing", NULL, N_("action"),
3046                   N_("handling for missing objects"), PARSE_OPT_NONEG,
3047                   option_parse_missing_action },
3048                 OPT_BOOL(0, "exclude-promisor-objects", &exclude_promisor_objects,
3049                          N_("do not pack objects in promisor packfiles")),
3050                 OPT_END(),
3051         };
3052
3053         if (DFS_NUM_STATES > (1 << OE_DFS_STATE_BITS))
3054                 BUG("too many dfs states, increase OE_DFS_STATE_BITS");
3055
3056         check_replace_refs = 0;
3057
3058         reset_pack_idx_option(&pack_idx_opts);
3059         git_config(git_pack_config, NULL);
3060
3061         progress = isatty(2);
3062         argc = parse_options(argc, argv, prefix, pack_objects_options,
3063                              pack_usage, 0);
3064
3065         if (argc) {
3066                 base_name = argv[0];
3067                 argc--;
3068         }
3069         if (pack_to_stdout != !base_name || argc)
3070                 usage_with_options(pack_usage, pack_objects_options);
3071
3072         if (depth >= (1 << OE_DEPTH_BITS)) {
3073                 warning(_("delta chain depth %d is too deep, forcing %d"),
3074                         depth, (1 << OE_DEPTH_BITS) - 1);
3075                 depth = (1 << OE_DEPTH_BITS) - 1;
3076         }
3077
3078         argv_array_push(&rp, "pack-objects");
3079         if (thin) {
3080                 use_internal_rev_list = 1;
3081                 argv_array_push(&rp, shallow
3082                                 ? "--objects-edge-aggressive"
3083                                 : "--objects-edge");
3084         } else
3085                 argv_array_push(&rp, "--objects");
3086
3087         if (rev_list_all) {
3088                 use_internal_rev_list = 1;
3089                 argv_array_push(&rp, "--all");
3090         }
3091         if (rev_list_reflog) {
3092                 use_internal_rev_list = 1;
3093                 argv_array_push(&rp, "--reflog");
3094         }
3095         if (rev_list_index) {
3096                 use_internal_rev_list = 1;
3097                 argv_array_push(&rp, "--indexed-objects");
3098         }
3099         if (rev_list_unpacked) {
3100                 use_internal_rev_list = 1;
3101                 argv_array_push(&rp, "--unpacked");
3102         }
3103
3104         if (exclude_promisor_objects) {
3105                 use_internal_rev_list = 1;
3106                 fetch_if_missing = 0;
3107                 argv_array_push(&rp, "--exclude-promisor-objects");
3108         }
3109
3110         if (!reuse_object)
3111                 reuse_delta = 0;
3112         if (pack_compression_level == -1)
3113                 pack_compression_level = Z_DEFAULT_COMPRESSION;
3114         else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
3115                 die("bad pack compression level %d", pack_compression_level);
3116
3117         if (!delta_search_threads)      /* --threads=0 means autodetect */
3118                 delta_search_threads = online_cpus();
3119
3120 #ifdef NO_PTHREADS
3121         if (delta_search_threads != 1)
3122                 warning("no threads support, ignoring --threads");
3123 #endif
3124         if (!pack_to_stdout && !pack_size_limit)
3125                 pack_size_limit = pack_size_limit_cfg;
3126         if (pack_to_stdout && pack_size_limit)
3127                 die("--max-pack-size cannot be used to build a pack for transfer.");
3128         if (pack_size_limit && pack_size_limit < 1024*1024) {
3129                 warning("minimum pack size limit is 1 MiB");
3130                 pack_size_limit = 1024*1024;
3131         }
3132
3133         if (!pack_to_stdout && thin)
3134                 die("--thin cannot be used to build an indexable pack.");
3135
3136         if (keep_unreachable && unpack_unreachable)
3137                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
3138         if (!rev_list_all || !rev_list_reflog || !rev_list_index)
3139                 unpack_unreachable_expiration = 0;
3140
3141         if (filter_options.choice) {
3142                 if (!pack_to_stdout)
3143                         die("cannot use --filter without --stdout.");
3144                 use_bitmap_index = 0;
3145         }
3146
3147         /*
3148          * "soft" reasons not to use bitmaps - for on-disk repack by default we want
3149          *
3150          * - to produce good pack (with bitmap index not-yet-packed objects are
3151          *   packed in suboptimal order).
3152          *
3153          * - to use more robust pack-generation codepath (avoiding possible
3154          *   bugs in bitmap code and possible bitmap index corruption).
3155          */
3156         if (!pack_to_stdout)
3157                 use_bitmap_index_default = 0;
3158
3159         if (use_bitmap_index < 0)
3160                 use_bitmap_index = use_bitmap_index_default;
3161
3162         /* "hard" reasons not to use bitmaps; these just won't work at all */
3163         if (!use_internal_rev_list || (!pack_to_stdout && write_bitmap_index) || is_repository_shallow())
3164                 use_bitmap_index = 0;
3165
3166         if (pack_to_stdout || !rev_list_all)
3167                 write_bitmap_index = 0;
3168
3169         if (progress && all_progress_implied)
3170                 progress = 2;
3171
3172         if (ignore_packed_keep) {
3173                 struct packed_git *p;
3174                 for (p = get_packed_git(the_repository); p; p = p->next)
3175                         if (p->pack_local && p->pack_keep)
3176                                 break;
3177                 if (!p) /* no keep-able packs found */
3178                         ignore_packed_keep = 0;
3179         }
3180         if (local) {
3181                 /*
3182                  * unlike ignore_packed_keep above, we do not want to
3183                  * unset "local" based on looking at packs, as it
3184                  * also covers non-local objects
3185                  */
3186                 struct packed_git *p;
3187                 for (p = get_packed_git(the_repository); p; p = p->next) {
3188                         if (!p->pack_local) {
3189                                 have_non_local_packs = 1;
3190                                 break;
3191                         }
3192                 }
3193         }
3194
3195         if (progress)
3196                 progress_state = start_progress(_("Counting objects"), 0);
3197         if (!use_internal_rev_list)
3198                 read_object_list_from_stdin();
3199         else {
3200                 get_object_list(rp.argc, rp.argv);
3201                 argv_array_clear(&rp);
3202         }
3203         cleanup_preferred_base();
3204         if (include_tag && nr_result)
3205                 for_each_ref(add_ref_tag, NULL);
3206         stop_progress(&progress_state);
3207
3208         if (non_empty && !nr_result)
3209                 return 0;
3210         if (nr_result)
3211                 prepare_pack(window, depth);
3212         write_pack_file();
3213         if (progress)
3214                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
3215                         " reused %"PRIu32" (delta %"PRIu32")\n",
3216                         written, written_delta, reused, reused_delta);
3217         return 0;
3218 }