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

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "attr.h"
   4 #include "object.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "delta.h"
  10 #include "pack.h"
  11 #include "pack-revindex.h"
  12 #include "csum-file.h"
  13 #include "tree-walk.h"
  14 #include "diff.h"
  15 #include "revision.h"
  16 #include "list-objects.h"
  17 #include "pack-objects.h"
  18 #include "progress.h"
  19 #include "refs.h"
  20 #include "streaming.h"
  21 #include "thread-utils.h"
  22 #include "pack-bitmap.h"
  23 #include "reachable.h"
  24 #include "sha1-array.h"
  25 #include "argv-array.h"
  26 #include "mru.h"
  27
  28 static const char *pack_usage[] = {
  29         N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
  30         N_("git pack-objects [<options>...] <base-name> [< <ref-list> | < <object-list>]"),
  31         NULL
  32 };
  33
  34 /*
  35  * Objects we are going to pack are collected in the `to_pack` structure.
  36  * It contains an array (dynamically expanded) of the object data, and a map
  37  * that can resolve SHA1s to their position in the array.
  38  */
  39 static struct packing_data to_pack;
  40
  41 static struct pack_idx_entry **written_list;
  42 static uint32_t nr_result, nr_written;
  43
  44 static int non_empty;
  45 static int reuse_delta = 1, reuse_object = 1;
  46 static int keep_unreachable, unpack_unreachable, include_tag;
  47 static unsigned long unpack_unreachable_expiration;
  48 static int pack_loose_unreachable;
  49 static int local;
  50 static int have_non_local_packs;
  51 static int incremental;
  52 static int ignore_packed_keep;
  53 static int allow_ofs_delta;
  54 static struct pack_idx_option pack_idx_opts;
  55 static const char *base_name;
  56 static int progress = 1;
  57 static int window = 10;
  58 static unsigned long pack_size_limit;
  59 static int depth = 50;
  60 static int delta_search_threads;
  61 static int pack_to_stdout;
  62 static int num_preferred_base;
  63 static struct progress *progress_state;
  64
  65 static struct packed_git *reuse_packfile;
  66 static uint32_t reuse_packfile_objects;
  67 static off_t reuse_packfile_offset;
  68
  69 static int use_bitmap_index_default = 1;
  70 static int use_bitmap_index = -1;
  71 static int write_bitmap_index;
  72 static uint16_t write_bitmap_options;
  73
  74 static unsigned long delta_cache_size = 0;
  75 static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  76 static unsigned long cache_max_small_delta_size = 1000;
  77
  78 static unsigned long window_memory_limit = 0;
  79
  80 /*
  81  * stats
  82  */
  83 static uint32_t written, written_delta;
  84 static uint32_t reused, reused_delta;
  85
  86 /*
  87  * Indexed commits
  88  */
  89 static struct commit **indexed_commits;
  90 static unsigned int indexed_commits_nr;
  91 static unsigned int indexed_commits_alloc;
  92
  93 static void index_commit_for_bitmap(struct commit *commit)
  94 {
  95         if (indexed_commits_nr >= indexed_commits_alloc) {
  96                 indexed_commits_alloc = (indexed_commits_alloc + 32) * 2;
  97                 REALLOC_ARRAY(indexed_commits, indexed_commits_alloc);
  98         }
  99
 100         indexed_commits[indexed_commits_nr++] = commit;
 101 }
 102
 103 static void *get_delta(struct object_entry *entry)
 104 {
 105         unsigned long size, base_size, delta_size;
 106         void *buf, *base_buf, *delta_buf;
 107         enum object_type type;
 108
 109         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 110         if (!buf)
 111                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 112         base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
 113         if (!base_buf)
 114                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 115         delta_buf = diff_delta(base_buf, base_size,
 116                                buf, size, &delta_size, 0);
 117         if (!delta_buf || delta_size != entry->delta_size)
 118                 die("delta size changed");
 119         free(buf);
 120         free(base_buf);
 121         return delta_buf;
 122 }
 123
 124 static unsigned long do_compress(void **pptr, unsigned long size)
 125 {
 126         git_zstream stream;
 127         void *in, *out;
 128         unsigned long maxsize;
 129
 130         git_deflate_init(&stream, pack_compression_level);
 131         maxsize = git_deflate_bound(&stream, size);
 132
 133         in = *pptr;
 134         out = xmalloc(maxsize);
 135         *pptr = out;
 136
 137         stream.next_in = in;
 138         stream.avail_in = size;
 139         stream.next_out = out;
 140         stream.avail_out = maxsize;
 141         while (git_deflate(&stream, Z_FINISH) == Z_OK)
 142                 ; /* nothing */
 143         git_deflate_end(&stream);
 144
 145         free(in);
 146         return stream.total_out;
 147 }
 148
 149 static unsigned long write_large_blob_data(struct git_istream *st, struct sha1file *f,
 150                                            const unsigned char *sha1)
 151 {
 152         git_zstream stream;
 153         unsigned char ibuf[1024 * 16];
 154         unsigned char obuf[1024 * 16];
 155         unsigned long olen = 0;
 156
 157         git_deflate_init(&stream, pack_compression_level);
 158
 159         for (;;) {
 160                 ssize_t readlen;
 161                 int zret = Z_OK;
 162                 readlen = read_istream(st, ibuf, sizeof(ibuf));
 163                 if (readlen == -1)
 164                         die(_("unable to read %s"), sha1_to_hex(sha1));
 165
 166                 stream.next_in = ibuf;
 167                 stream.avail_in = readlen;
 168                 while ((stream.avail_in || readlen == 0) &&
 169                        (zret == Z_OK || zret == Z_BUF_ERROR)) {
 170                         stream.next_out = obuf;
 171                         stream.avail_out = sizeof(obuf);
 172                         zret = git_deflate(&stream, readlen ? 0 : Z_FINISH);
 173                         sha1write(f, obuf, stream.next_out - obuf);
 174                         olen += stream.next_out - obuf;
 175                 }
 176                 if (stream.avail_in)
 177                         die(_("deflate error (%d)"), zret);
 178                 if (readlen == 0) {
 179                         if (zret != Z_STREAM_END)
 180                                 die(_("deflate error (%d)"), zret);
 181                         break;
 182                 }
 183         }
 184         git_deflate_end(&stream);
 185         return olen;
 186 }
 187
 188 /*
 189  * we are going to reuse the existing object data as is.  make
 190  * sure it is not corrupt.
 191  */
 192 static int check_pack_inflate(struct packed_git *p,
 193                 struct pack_window **w_curs,
 194                 off_t offset,
 195                 off_t len,
 196                 unsigned long expect)
 197 {
 198         git_zstream stream;
 199         unsigned char fakebuf[4096], *in;
 200         int st;
 201
 202         memset(&stream, 0, sizeof(stream));
 203         git_inflate_init(&stream);
 204         do {
 205                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 206                 stream.next_in = in;
 207                 stream.next_out = fakebuf;
 208                 stream.avail_out = sizeof(fakebuf);
 209                 st = git_inflate(&stream, Z_FINISH);
 210                 offset += stream.next_in - in;
 211         } while (st == Z_OK || st == Z_BUF_ERROR);
 212         git_inflate_end(&stream);
 213         return (st == Z_STREAM_END &&
 214                 stream.total_out == expect &&
 215                 stream.total_in == len) ? 0 : -1;
 216 }
 217
 218 static void copy_pack_data(struct sha1file *f,
 219                 struct packed_git *p,
 220                 struct pack_window **w_curs,
 221                 off_t offset,
 222                 off_t len)
 223 {
 224         unsigned char *in;
 225         unsigned long avail;
 226
 227         while (len) {
 228                 in = use_pack(p, w_curs, offset, &avail);
 229                 if (avail > len)
 230                         avail = (unsigned long)len;
 231                 sha1write(f, in, avail);
 232                 offset += avail;
 233                 len -= avail;
 234         }
 235 }
 236
 237 /* Return 0 if we will bust the pack-size limit */
 238 static unsigned long write_no_reuse_object(struct sha1file *f, struct object_entry *entry,
 239                                            unsigned long limit, int usable_delta)
 240 {
 241         unsigned long size, datalen;
 242         unsigned char header[10], dheader[10];
 243         unsigned hdrlen;
 244         enum object_type type;
 245         void *buf;
 246         struct git_istream *st = NULL;
 247
 248         if (!usable_delta) {
 249                 if (entry->type == OBJ_BLOB &&
 250                     entry->size > big_file_threshold &&
 251                     (st = open_istream(entry->idx.sha1, &type, &size, NULL)) != NULL)
 252                         buf = NULL;
 253                 else {
 254                         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 255                         if (!buf)
 256                                 die(_("unable to read %s"), sha1_to_hex(entry->idx.sha1));
 257                 }
 258                 /*
 259                  * make sure no cached delta data remains from a
 260                  * previous attempt before a pack split occurred.
 261                  */
 262                 free(entry->delta_data);
 263                 entry->delta_data = NULL;
 264                 entry->z_delta_size = 0;
 265         } else if (entry->delta_data) {
 266                 size = entry->delta_size;
 267                 buf = entry->delta_data;
 268                 entry->delta_data = NULL;
 269                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 270                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 271         } else {
 272                 buf = get_delta(entry);
 273                 size = entry->delta_size;
 274                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 275                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 276         }
 277
 278         if (st) /* large blob case, just assume we don't compress well */
 279                 datalen = size;
 280         else if (entry->z_delta_size)
 281                 datalen = entry->z_delta_size;
 282         else
 283                 datalen = do_compress(&buf, size);
 284
 285         /*
 286          * The object header is a byte of 'type' followed by zero or
 287          * more bytes of length.
 288          */
 289         hdrlen = encode_in_pack_object_header(type, size, header);
 290
 291         if (type == OBJ_OFS_DELTA) {
 292                 /*
 293                  * Deltas with relative base contain an additional
 294                  * encoding of the relative offset for the delta
 295                  * base from this object's position in the pack.
 296                  */
 297                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 298                 unsigned pos = sizeof(dheader) - 1;
 299                 dheader[pos] = ofs & 127;
 300                 while (ofs >>= 7)
 301                         dheader[--pos] = 128 | (--ofs & 127);
 302                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 303                         if (st)
 304                                 close_istream(st);
 305                         free(buf);
 306                         return 0;
 307                 }
 308                 sha1write(f, header, hdrlen);
 309                 sha1write(f, dheader + pos, sizeof(dheader) - pos);
 310                 hdrlen += sizeof(dheader) - pos;
 311         } else if (type == OBJ_REF_DELTA) {
 312                 /*
 313                  * Deltas with a base reference contain
 314                  * an additional 20 bytes for the base sha1.
 315                  */
 316                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 317                         if (st)
 318                                 close_istream(st);
 319                         free(buf);
 320                         return 0;
 321                 }
 322                 sha1write(f, header, hdrlen);
 323                 sha1write(f, entry->delta->idx.sha1, 20);
 324                 hdrlen += 20;
 325         } else {
 326                 if (limit && hdrlen + datalen + 20 >= limit) {
 327                         if (st)
 328                                 close_istream(st);
 329                         free(buf);
 330                         return 0;
 331                 }
 332                 sha1write(f, header, hdrlen);
 333         }
 334         if (st) {
 335                 datalen = write_large_blob_data(st, f, entry->idx.sha1);
 336                 close_istream(st);
 337         } else {
 338                 sha1write(f, buf, datalen);
 339                 free(buf);
 340         }
 341
 342         return hdrlen + datalen;
 343 }
 344
 345 /* Return 0 if we will bust the pack-size limit */
 346 static off_t write_reuse_object(struct sha1file *f, struct object_entry *entry,
 347                                 unsigned long limit, int usable_delta)
 348 {
 349         struct packed_git *p = entry->in_pack;
 350         struct pack_window *w_curs = NULL;
 351         struct revindex_entry *revidx;
 352         off_t offset;
 353         enum object_type type = entry->type;
 354         off_t datalen;
 355         unsigned char header[10], dheader[10];
 356         unsigned hdrlen;
 357
 358         if (entry->delta)
 359                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 360                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 361         hdrlen = encode_in_pack_object_header(type, entry->size, header);
 362
 363         offset = entry->in_pack_offset;
 364         revidx = find_pack_revindex(p, offset);
 365         datalen = revidx[1].offset - offset;
 366         if (!pack_to_stdout && p->index_version > 1 &&
 367             check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 368                 error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 369                 unuse_pack(&w_curs);
 370                 return write_no_reuse_object(f, entry, limit, usable_delta);
 371         }
 372
 373         offset += entry->in_pack_header_size;
 374         datalen -= entry->in_pack_header_size;
 375
 376         if (!pack_to_stdout && p->index_version == 1 &&
 377             check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 378                 error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 379                 unuse_pack(&w_curs);
 380                 return write_no_reuse_object(f, entry, limit, usable_delta);
 381         }
 382
 383         if (type == OBJ_OFS_DELTA) {
 384                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 385                 unsigned pos = sizeof(dheader) - 1;
 386                 dheader[pos] = ofs & 127;
 387                 while (ofs >>= 7)
 388                         dheader[--pos] = 128 | (--ofs & 127);
 389                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 390                         unuse_pack(&w_curs);
 391                         return 0;
 392                 }
 393                 sha1write(f, header, hdrlen);
 394                 sha1write(f, dheader + pos, sizeof(dheader) - pos);
 395                 hdrlen += sizeof(dheader) - pos;
 396                 reused_delta++;
 397         } else if (type == OBJ_REF_DELTA) {
 398                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 399                         unuse_pack(&w_curs);
 400                         return 0;
 401                 }
 402                 sha1write(f, header, hdrlen);
 403                 sha1write(f, entry->delta->idx.sha1, 20);
 404                 hdrlen += 20;
 405                 reused_delta++;
 406         } else {
 407                 if (limit && hdrlen + datalen + 20 >= limit) {
 408                         unuse_pack(&w_curs);
 409                         return 0;
 410                 }
 411                 sha1write(f, header, hdrlen);
 412         }
 413         copy_pack_data(f, p, &w_curs, offset, datalen);
 414         unuse_pack(&w_curs);
 415         reused++;
 416         return hdrlen + datalen;
 417 }
 418
 419 /* Return 0 if we will bust the pack-size limit */
 420 static off_t write_object(struct sha1file *f,
 421                           struct object_entry *entry,
 422                           off_t write_offset)
 423 {
 424         unsigned long limit;
 425         off_t len;
 426         int usable_delta, to_reuse;
 427
 428         if (!pack_to_stdout)
 429                 crc32_begin(f);
 430
 431         /* apply size limit if limited packsize and not first object */
 432         if (!pack_size_limit || !nr_written)
 433                 limit = 0;
 434         else if (pack_size_limit <= write_offset)
 435                 /*
 436                  * the earlier object did not fit the limit; avoid
 437                  * mistaking this with unlimited (i.e. limit = 0).
 438                  */
 439                 limit = 1;
 440         else
 441                 limit = pack_size_limit - write_offset;
 442
 443         if (!entry->delta)
 444                 usable_delta = 0;       /* no delta */
 445         else if (!pack_size_limit)
 446                usable_delta = 1;        /* unlimited packfile */
 447         else if (entry->delta->idx.offset == (off_t)-1)
 448                 usable_delta = 0;       /* base was written to another pack */
 449         else if (entry->delta->idx.offset)
 450                 usable_delta = 1;       /* base already exists in this pack */
 451         else
 452                 usable_delta = 0;       /* base could end up in another pack */
 453
 454         if (!reuse_object)
 455                 to_reuse = 0;   /* explicit */
 456         else if (!entry->in_pack)
 457                 to_reuse = 0;   /* can't reuse what we don't have */
 458         else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
 459                                 /* check_object() decided it for us ... */
 460                 to_reuse = usable_delta;
 461                                 /* ... but pack split may override that */
 462         else if (entry->type != entry->in_pack_type)
 463                 to_reuse = 0;   /* pack has delta which is unusable */
 464         else if (entry->delta)
 465                 to_reuse = 0;   /* we want to pack afresh */
 466         else
 467                 to_reuse = 1;   /* we have it in-pack undeltified,
 468                                  * and we do not need to deltify it.
 469                                  */
 470
 471         if (!to_reuse)
 472                 len = write_no_reuse_object(f, entry, limit, usable_delta);
 473         else
 474                 len = write_reuse_object(f, entry, limit, usable_delta);
 475         if (!len)
 476                 return 0;
 477
 478         if (usable_delta)
 479                 written_delta++;
 480         written++;
 481         if (!pack_to_stdout)
 482                 entry->idx.crc32 = crc32_end(f);
 483         return len;
 484 }
 485
 486 enum write_one_status {
 487         WRITE_ONE_SKIP = -1, /* already written */
 488         WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 489         WRITE_ONE_WRITTEN = 1, /* normal */
 490         WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 491 };
 492
 493 static enum write_one_status write_one(struct sha1file *f,
 494                                        struct object_entry *e,
 495                                        off_t *offset)
 496 {
 497         off_t size;
 498         int recursing;
 499
 500         /*
 501          * we set offset to 1 (which is an impossible value) to mark
 502          * the fact that this object is involved in "write its base
 503          * first before writing a deltified object" recursion.
 504          */
 505         recursing = (e->idx.offset == 1);
 506         if (recursing) {
 507                 warning("recursive delta detected for object %s",
 508                         sha1_to_hex(e->idx.sha1));
 509                 return WRITE_ONE_RECURSIVE;
 510         } else if (e->idx.offset || e->preferred_base) {
 511                 /* offset is non zero if object is written already. */
 512                 return WRITE_ONE_SKIP;
 513         }
 514
 515         /* if we are deltified, write out base object first. */
 516         if (e->delta) {
 517                 e->idx.offset = 1; /* now recurse */
 518                 switch (write_one(f, e->delta, offset)) {
 519                 case WRITE_ONE_RECURSIVE:
 520                         /* we cannot depend on this one */
 521                         e->delta = NULL;
 522                         break;
 523                 default:
 524                         break;
 525                 case WRITE_ONE_BREAK:
 526                         e->idx.offset = recursing;
 527                         return WRITE_ONE_BREAK;
 528                 }
 529         }
 530
 531         e->idx.offset = *offset;
 532         size = write_object(f, e, *offset);
 533         if (!size) {
 534                 e->idx.offset = recursing;
 535                 return WRITE_ONE_BREAK;
 536         }
 537         written_list[nr_written++] = &e->idx;
 538
 539         /* make sure off_t is sufficiently large not to wrap */
 540         if (signed_add_overflows(*offset, size))
 541                 die("pack too large for current definition of off_t");
 542         *offset += size;
 543         return WRITE_ONE_WRITTEN;
 544 }
 545
 546 static int mark_tagged(const char *path, const struct object_id *oid, int flag,
 547                        void *cb_data)
 548 {
 549         unsigned char peeled[20];
 550         struct object_entry *entry = packlist_find(&to_pack, oid->hash, NULL);
 551
 552         if (entry)
 553                 entry->tagged = 1;
 554         if (!peel_ref(path, peeled)) {
 555                 entry = packlist_find(&to_pack, peeled, NULL);
 556                 if (entry)
 557                         entry->tagged = 1;
 558         }
 559         return 0;
 560 }
 561
 562 static inline void add_to_write_order(struct object_entry **wo,
 563                                unsigned int *endp,
 564                                struct object_entry *e)
 565 {
 566         if (e->filled)
 567                 return;
 568         wo[(*endp)++] = e;
 569         e->filled = 1;
 570 }
 571
 572 static void add_descendants_to_write_order(struct object_entry **wo,
 573                                            unsigned int *endp,
 574                                            struct object_entry *e)
 575 {
 576         int add_to_order = 1;
 577         while (e) {
 578                 if (add_to_order) {
 579                         struct object_entry *s;
 580                         /* add this node... */
 581                         add_to_write_order(wo, endp, e);
 582                         /* all its siblings... */
 583                         for (s = e->delta_sibling; s; s = s->delta_sibling) {
 584                                 add_to_write_order(wo, endp, s);
 585                         }
 586                 }
 587                 /* drop down a level to add left subtree nodes if possible */
 588                 if (e->delta_child) {
 589                         add_to_order = 1;
 590                         e = e->delta_child;
 591                 } else {
 592                         add_to_order = 0;
 593                         /* our sibling might have some children, it is next */
 594                         if (e->delta_sibling) {
 595                                 e = e->delta_sibling;
 596                                 continue;
 597                         }
 598                         /* go back to our parent node */
 599                         e = e->delta;
 600                         while (e && !e->delta_sibling) {
 601                                 /* we're on the right side of a subtree, keep
 602                                  * going up until we can go right again */
 603                                 e = e->delta;
 604                         }
 605                         if (!e) {
 606                                 /* done- we hit our original root node */
 607                                 return;
 608                         }
 609                         /* pass it off to sibling at this level */
 610                         e = e->delta_sibling;
 611                 }
 612         };
 613 }
 614
 615 static void add_family_to_write_order(struct object_entry **wo,
 616                                       unsigned int *endp,
 617                                       struct object_entry *e)
 618 {
 619         struct object_entry *root;
 620
 621         for (root = e; root->delta; root = root->delta)
 622                 ; /* nothing */
 623         add_descendants_to_write_order(wo, endp, root);
 624 }
 625
 626 static struct object_entry **compute_write_order(void)
 627 {
 628         unsigned int i, wo_end, last_untagged;
 629
 630         struct object_entry **wo;
 631         struct object_entry *objects = to_pack.objects;
 632
 633         for (i = 0; i < to_pack.nr_objects; i++) {
 634                 objects[i].tagged = 0;
 635                 objects[i].filled = 0;
 636                 objects[i].delta_child = NULL;
 637                 objects[i].delta_sibling = NULL;
 638         }
 639
 640         /*
 641          * Fully connect delta_child/delta_sibling network.
 642          * Make sure delta_sibling is sorted in the original
 643          * recency order.
 644          */
 645         for (i = to_pack.nr_objects; i > 0;) {
 646                 struct object_entry *e = &objects[--i];
 647                 if (!e->delta)
 648                         continue;
 649                 /* Mark me as the first child */
 650                 e->delta_sibling = e->delta->delta_child;
 651                 e->delta->delta_child = e;
 652         }
 653
 654         /*
 655          * Mark objects that are at the tip of tags.
 656          */
 657         for_each_tag_ref(mark_tagged, NULL);
 658
 659         /*
 660          * Give the objects in the original recency order until
 661          * we see a tagged tip.
 662          */
 663         ALLOC_ARRAY(wo, to_pack.nr_objects);
 664         for (i = wo_end = 0; i < to_pack.nr_objects; i++) {
 665                 if (objects[i].tagged)
 666                         break;
 667                 add_to_write_order(wo, &wo_end, &objects[i]);
 668         }
 669         last_untagged = i;
 670
 671         /*
 672          * Then fill all the tagged tips.
 673          */
 674         for (; i < to_pack.nr_objects; i++) {
 675                 if (objects[i].tagged)
 676                         add_to_write_order(wo, &wo_end, &objects[i]);
 677         }
 678
 679         /*
 680          * And then all remaining commits and tags.
 681          */
 682         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 683                 if (objects[i].type != OBJ_COMMIT &&
 684                     objects[i].type != OBJ_TAG)
 685                         continue;
 686                 add_to_write_order(wo, &wo_end, &objects[i]);
 687         }
 688
 689         /*
 690          * And then all the trees.
 691          */
 692         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 693                 if (objects[i].type != OBJ_TREE)
 694                         continue;
 695                 add_to_write_order(wo, &wo_end, &objects[i]);
 696         }
 697
 698         /*
 699          * Finally all the rest in really tight order
 700          */
 701         for (i = last_untagged; i < to_pack.nr_objects; i++) {
 702                 if (!objects[i].filled)
 703                         add_family_to_write_order(wo, &wo_end, &objects[i]);
 704         }
 705
 706         if (wo_end != to_pack.nr_objects)
 707                 die("ordered %u objects, expected %"PRIu32, wo_end, to_pack.nr_objects);
 708
 709         return wo;
 710 }
 711
 712 static off_t write_reused_pack(struct sha1file *f)
 713 {
 714         unsigned char buffer[8192];
 715         off_t to_write, total;
 716         int fd;
 717
 718         if (!is_pack_valid(reuse_packfile))
 719                 die("packfile is invalid: %s", reuse_packfile->pack_name);
 720
 721         fd = git_open(reuse_packfile->pack_name);
 722         if (fd < 0)
 723                 die_errno("unable to open packfile for reuse: %s",
 724                           reuse_packfile->pack_name);
 725
 726         if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
 727                 die_errno("unable to seek in reused packfile");
 728
 729         if (reuse_packfile_offset < 0)
 730                 reuse_packfile_offset = reuse_packfile->pack_size - 20;
 731
 732         total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 733
 734         while (to_write) {
 735                 int read_pack = xread(fd, buffer, sizeof(buffer));
 736
 737                 if (read_pack <= 0)
 738                         die_errno("unable to read from reused packfile");
 739
 740                 if (read_pack > to_write)
 741                         read_pack = to_write;
 742
 743                 sha1write(f, buffer, read_pack);
 744                 to_write -= read_pack;
 745
 746                 /*
 747                  * We don't know the actual number of objects written,
 748                  * only how many bytes written, how many bytes total, and
 749                  * how many objects total. So we can fake it by pretending all
 750                  * objects we are writing are the same size. This gives us a
 751                  * smooth progress meter, and at the end it matches the true
 752                  * answer.
 753                  */
 754                 written = reuse_packfile_objects *
 755                                 (((double)(total - to_write)) / total);
 756                 display_progress(progress_state, written);
 757         }
 758
 759         close(fd);
 760         written = reuse_packfile_objects;
 761         display_progress(progress_state, written);
 762         return reuse_packfile_offset - sizeof(struct pack_header);
 763 }
 764
 765 static const char no_split_warning[] = N_(
 766 "disabling bitmap writing, packs are split due to pack.packSizeLimit"
 767 );
 768
 769 static void write_pack_file(void)
 770 {
 771         uint32_t i = 0, j;
 772         struct sha1file *f;
 773         off_t offset;
 774         uint32_t nr_remaining = nr_result;
 775         time_t last_mtime = 0;
 776         struct object_entry **write_order;
 777
 778         if (progress > pack_to_stdout)
 779                 progress_state = start_progress(_("Writing objects"), nr_result);
 780         ALLOC_ARRAY(written_list, to_pack.nr_objects);
 781         write_order = compute_write_order();
 782
 783         do {
 784                 unsigned char sha1[20];
 785                 char *pack_tmp_name = NULL;
 786
 787                 if (pack_to_stdout)
 788                         f = sha1fd_throughput(1, "<stdout>", progress_state);
 789                 else
 790                         f = create_tmp_packfile(&pack_tmp_name);
 791
 792                 offset = write_pack_header(f, nr_remaining);
 793
 794                 if (reuse_packfile) {
 795                         off_t packfile_size;
 796                         assert(pack_to_stdout);
 797
 798                         packfile_size = write_reused_pack(f);
 799                         offset += packfile_size;
 800                 }
 801
 802                 nr_written = 0;
 803                 for (; i < to_pack.nr_objects; i++) {
 804                         struct object_entry *e = write_order[i];
 805                         if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 806                                 break;
 807                         display_progress(progress_state, written);
 808                 }
 809
 810                 /*
 811                  * Did we write the wrong # entries in the header?
 812                  * If so, rewrite it like in fast-import
 813                  */
 814                 if (pack_to_stdout) {
 815                         sha1close(f, sha1, CSUM_CLOSE);
 816                 } else if (nr_written == nr_remaining) {
 817                         sha1close(f, sha1, CSUM_FSYNC);
 818                 } else {
 819                         int fd = sha1close(f, sha1, 0);
 820                         fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 821                                                  nr_written, sha1, offset);
 822                         close(fd);
 823                         if (write_bitmap_index) {
 824                                 warning(_(no_split_warning));
 825                                 write_bitmap_index = 0;
 826                         }
 827                 }
 828
 829                 if (!pack_to_stdout) {
 830                         struct stat st;
 831                         struct strbuf tmpname = STRBUF_INIT;
 832
 833                         /*
 834                          * Packs are runtime accessed in their mtime
 835                          * order since newer packs are more likely to contain
 836                          * younger objects.  So if we are creating multiple
 837                          * packs then we should modify the mtime of later ones
 838                          * to preserve this property.
 839                          */
 840                         if (stat(pack_tmp_name, &st) < 0) {
 841                                 warning_errno("failed to stat %s", pack_tmp_name);
 842                         } else if (!last_mtime) {
 843                                 last_mtime = st.st_mtime;
 844                         } else {
 845                                 struct utimbuf utb;
 846                                 utb.actime = st.st_atime;
 847                                 utb.modtime = --last_mtime;
 848                                 if (utime(pack_tmp_name, &utb) < 0)
 849                                         warning_errno("failed utime() on %s", pack_tmp_name);
 850                         }
 851
 852                         strbuf_addf(&tmpname, "%s-", base_name);
 853
 854                         if (write_bitmap_index) {
 855                                 bitmap_writer_set_checksum(sha1);
 856                                 bitmap_writer_build_type_index(written_list, nr_written);
 857                         }
 858
 859                         finish_tmp_packfile(&tmpname, pack_tmp_name,
 860                                             written_list, nr_written,
 861                                             &pack_idx_opts, sha1);
 862
 863                         if (write_bitmap_index) {
 864                                 strbuf_addf(&tmpname, "%s.bitmap", sha1_to_hex(sha1));
 865
 866                                 stop_progress(&progress_state);
 867
 868                                 bitmap_writer_show_progress(progress);
 869                                 bitmap_writer_reuse_bitmaps(&to_pack);
 870                                 bitmap_writer_select_commits(indexed_commits, indexed_commits_nr, -1);
 871                                 bitmap_writer_build(&to_pack);
 872                                 bitmap_writer_finish(written_list, nr_written,
 873                                                      tmpname.buf, write_bitmap_options);
 874                                 write_bitmap_index = 0;
 875                         }
 876
 877                         strbuf_release(&tmpname);
 878                         free(pack_tmp_name);
 879                         puts(sha1_to_hex(sha1));
 880                 }
 881
 882                 /* mark written objects as written to previous pack */
 883                 for (j = 0; j < nr_written; j++) {
 884                         written_list[j]->offset = (off_t)-1;
 885                 }
 886                 nr_remaining -= nr_written;
 887         } while (nr_remaining && i < to_pack.nr_objects);
 888
 889         free(written_list);
 890         free(write_order);
 891         stop_progress(&progress_state);
 892         if (written != nr_result)
 893                 die("wrote %"PRIu32" objects while expecting %"PRIu32,
 894                         written, nr_result);
 895 }
 896
 897 static int no_try_delta(const char *path)
 898 {
 899         static struct attr_check *check;
 900
 901         if (!check)
 902                 check = attr_check_initl("delta", NULL);
 903         if (git_check_attr(path, check))
 904                 return 0;
 905         if (ATTR_FALSE(check->items[0].value))
 906                 return 1;
 907         return 0;
 908 }
 909
 910 /*
 911  * When adding an object, check whether we have already added it
 912  * to our packing list. If so, we can skip. However, if we are
 913  * being asked to excludei t, but the previous mention was to include
 914  * it, make sure to adjust its flags and tweak our numbers accordingly.
 915  *
 916  * As an optimization, we pass out the index position where we would have
 917  * found the item, since that saves us from having to look it up again a
 918  * few lines later when we want to add the new entry.
 919  */
 920 static int have_duplicate_entry(const unsigned char *sha1,
 921                                 int exclude,
 922                                 uint32_t *index_pos)
 923 {
 924         struct object_entry *entry;
 925
 926         entry = packlist_find(&to_pack, sha1, index_pos);
 927         if (!entry)
 928                 return 0;
 929
 930         if (exclude) {
 931                 if (!entry->preferred_base)
 932                         nr_result--;
 933                 entry->preferred_base = 1;
 934         }
 935
 936         return 1;
 937 }
 938
 939 static int want_found_object(int exclude, struct packed_git *p)
 940 {
 941         if (exclude)
 942                 return 1;
 943         if (incremental)
 944                 return 0;
 945
 946         /*
 947          * When asked to do --local (do not include an object that appears in a
 948          * pack we borrow from elsewhere) or --honor-pack-keep (do not include
 949          * an object that appears in a pack marked with .keep), finding a pack
 950          * that matches the criteria is sufficient for us to decide to omit it.
 951          * However, even if this pack does not satisfy the criteria, we need to
 952          * make sure no copy of this object appears in _any_ pack that makes us
 953          * to omit the object, so we need to check all the packs.
 954          *
 955          * We can however first check whether these options can possible matter;
 956          * if they do not matter we know we want the object in generated pack.
 957          * Otherwise, we signal "-1" at the end to tell the caller that we do
 958          * not know either way, and it needs to check more packs.
 959          */
 960         if (!ignore_packed_keep &&
 961             (!local || !have_non_local_packs))
 962                 return 1;
 963
 964         if (local && !p->pack_local)
 965                 return 0;
 966         if (ignore_packed_keep && p->pack_local && p->pack_keep)
 967                 return 0;
 968
 969         /* we don't know yet; keep looking for more packs */
 970         return -1;
 971 }
 972
 973 /*
 974  * Check whether we want the object in the pack (e.g., we do not want
 975  * objects found in non-local stores if the "--local" option was used).
 976  *
 977  * If the caller already knows an existing pack it wants to take the object
 978  * from, that is passed in *found_pack and *found_offset; otherwise this
 979  * function finds if there is any pack that has the object and returns the pack
 980  * and its offset in these variables.
 981  */
 982 static int want_object_in_pack(const unsigned char *sha1,
 983                                int exclude,
 984                                struct packed_git **found_pack,
 985                                off_t *found_offset)
 986 {
 987         struct mru_entry *entry;
 988         int want;
 989
 990         if (!exclude && local && has_loose_object_nonlocal(sha1))
 991                 return 0;
 992
 993         /*
 994          * If we already know the pack object lives in, start checks from that
 995          * pack - in the usual case when neither --local was given nor .keep files
 996          * are present we will determine the answer right now.
 997          */
 998         if (*found_pack) {
 999                 want = want_found_object(exclude, *found_pack);
1000                 if (want != -1)
1001                         return want;
1002         }
1003
1004         for (entry = packed_git_mru->head; entry; entry = entry->next) {
1005                 struct packed_git *p = entry->item;
1006                 off_t offset;
1007
1008                 if (p == *found_pack)
1009                         offset = *found_offset;
1010                 else
1011                         offset = find_pack_entry_one(sha1, p);
1012
1013                 if (offset) {
1014                         if (!*found_pack) {
1015                                 if (!is_pack_valid(p))
1016                                         continue;
1017                                 *found_offset = offset;
1018                                 *found_pack = p;
1019                         }
1020                         want = want_found_object(exclude, p);
1021                         if (!exclude && want > 0)
1022                                 mru_mark(packed_git_mru, entry);
1023                         if (want != -1)
1024                                 return want;
1025                 }
1026         }
1027
1028         return 1;
1029 }
1030
1031 static void create_object_entry(const unsigned char *sha1,
1032                                 enum object_type type,
1033                                 uint32_t hash,
1034                                 int exclude,
1035                                 int no_try_delta,
1036                                 uint32_t index_pos,
1037                                 struct packed_git *found_pack,
1038                                 off_t found_offset)
1039 {
1040         struct object_entry *entry;
1041
1042         entry = packlist_alloc(&to_pack, sha1, index_pos);
1043         entry->hash = hash;
1044         if (type)
1045                 entry->type = type;
1046         if (exclude)
1047                 entry->preferred_base = 1;
1048         else
1049                 nr_result++;
1050         if (found_pack) {
1051                 entry->in_pack = found_pack;
1052                 entry->in_pack_offset = found_offset;
1053         }
1054
1055         entry->no_try_delta = no_try_delta;
1056 }
1057
1058 static const char no_closure_warning[] = N_(
1059 "disabling bitmap writing, as some objects are not being packed"
1060 );
1061
1062 static int add_object_entry(const unsigned char *sha1, enum object_type type,
1063                             const char *name, int exclude)
1064 {
1065         struct packed_git *found_pack = NULL;
1066         off_t found_offset = 0;
1067         uint32_t index_pos;
1068
1069         if (have_duplicate_entry(sha1, exclude, &index_pos))
1070                 return 0;
1071
1072         if (!want_object_in_pack(sha1, exclude, &found_pack, &found_offset)) {
1073                 /* The pack is missing an object, so it will not have closure */
1074                 if (write_bitmap_index) {
1075                         warning(_(no_closure_warning));
1076                         write_bitmap_index = 0;
1077                 }
1078                 return 0;
1079         }
1080
1081         create_object_entry(sha1, type, pack_name_hash(name),
1082                             exclude, name && no_try_delta(name),
1083                             index_pos, found_pack, found_offset);
1084
1085         display_progress(progress_state, nr_result);
1086         return 1;
1087 }
1088
1089 static int add_object_entry_from_bitmap(const unsigned char *sha1,
1090                                         enum object_type type,
1091                                         int flags, uint32_t name_hash,
1092                                         struct packed_git *pack, off_t offset)
1093 {
1094         uint32_t index_pos;
1095
1096         if (have_duplicate_entry(sha1, 0, &index_pos))
1097                 return 0;
1098
1099         if (!want_object_in_pack(sha1, 0, &pack, &offset))
1100                 return 0;
1101
1102         create_object_entry(sha1, type, name_hash, 0, 0, index_pos, pack, offset);
1103
1104         display_progress(progress_state, nr_result);
1105         return 1;
1106 }
1107
1108 struct pbase_tree_cache {
1109         unsigned char sha1[20];
1110         int ref;
1111         int temporary;
1112         void *tree_data;
1113         unsigned long tree_size;
1114 };
1115
1116 static struct pbase_tree_cache *(pbase_tree_cache[256]);
1117 static int pbase_tree_cache_ix(const unsigned char *sha1)
1118 {
1119         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
1120 }
1121 static int pbase_tree_cache_ix_incr(int ix)
1122 {
1123         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
1124 }
1125
1126 static struct pbase_tree {
1127         struct pbase_tree *next;
1128         /* This is a phony "cache" entry; we are not
1129          * going to evict it or find it through _get()
1130          * mechanism -- this is for the toplevel node that
1131          * would almost always change with any commit.
1132          */
1133         struct pbase_tree_cache pcache;
1134 } *pbase_tree;
1135
1136 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
1137 {
1138         struct pbase_tree_cache *ent, *nent;
1139         void *data;
1140         unsigned long size;
1141         enum object_type type;
1142         int neigh;
1143         int my_ix = pbase_tree_cache_ix(sha1);
1144         int available_ix = -1;
1145
1146         /* pbase-tree-cache acts as a limited hashtable.
1147          * your object will be found at your index or within a few
1148          * slots after that slot if it is cached.
1149          */
1150         for (neigh = 0; neigh < 8; neigh++) {
1151                 ent = pbase_tree_cache[my_ix];
1152                 if (ent && !hashcmp(ent->sha1, sha1)) {
1153                         ent->ref++;
1154                         return ent;
1155                 }
1156                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
1157                          ((0 <= available_ix) &&
1158                           (!ent && pbase_tree_cache[available_ix])))
1159                         available_ix = my_ix;
1160                 if (!ent)
1161                         break;
1162                 my_ix = pbase_tree_cache_ix_incr(my_ix);
1163         }
1164
1165         /* Did not find one.  Either we got a bogus request or
1166          * we need to read and perhaps cache.
1167          */
1168         data = read_sha1_file(sha1, &type, &size);
1169         if (!data)
1170                 return NULL;
1171         if (type != OBJ_TREE) {
1172                 free(data);
1173                 return NULL;
1174         }
1175
1176         /* We need to either cache or return a throwaway copy */
1177
1178         if (available_ix < 0)
1179                 ent = NULL;
1180         else {
1181                 ent = pbase_tree_cache[available_ix];
1182                 my_ix = available_ix;
1183         }
1184
1185         if (!ent) {
1186                 nent = xmalloc(sizeof(*nent));
1187                 nent->temporary = (available_ix < 0);
1188         }
1189         else {
1190                 /* evict and reuse */
1191                 free(ent->tree_data);
1192                 nent = ent;
1193         }
1194         hashcpy(nent->sha1, sha1);
1195         nent->tree_data = data;
1196         nent->tree_size = size;
1197         nent->ref = 1;
1198         if (!nent->temporary)
1199                 pbase_tree_cache[my_ix] = nent;
1200         return nent;
1201 }
1202
1203 static void pbase_tree_put(struct pbase_tree_cache *cache)
1204 {
1205         if (!cache->temporary) {
1206                 cache->ref--;
1207                 return;
1208         }
1209         free(cache->tree_data);
1210         free(cache);
1211 }
1212
1213 static int name_cmp_len(const char *name)
1214 {
1215         int i;
1216         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1217                 ;
1218         return i;
1219 }
1220
1221 static void add_pbase_object(struct tree_desc *tree,
1222                              const char *name,
1223                              int cmplen,
1224                              const char *fullname)
1225 {
1226         struct name_entry entry;
1227         int cmp;
1228
1229         while (tree_entry(tree,&entry)) {
1230                 if (S_ISGITLINK(entry.mode))
1231                         continue;
1232                 cmp = tree_entry_len(&entry) != cmplen ? 1 :
1233                       memcmp(name, entry.path, cmplen);
1234                 if (cmp > 0)
1235                         continue;
1236                 if (cmp < 0)
1237                         return;
1238                 if (name[cmplen] != '/') {
1239                         add_object_entry(entry.oid->hash,
1240                                          object_type(entry.mode),
1241                                          fullname, 1);
1242                         return;
1243                 }
1244                 if (S_ISDIR(entry.mode)) {
1245                         struct tree_desc sub;
1246                         struct pbase_tree_cache *tree;
1247                         const char *down = name+cmplen+1;
1248                         int downlen = name_cmp_len(down);
1249
1250                         tree = pbase_tree_get(entry.oid->hash);
1251                         if (!tree)
1252                                 return;
1253                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1254
1255                         add_pbase_object(&sub, down, downlen, fullname);
1256                         pbase_tree_put(tree);
1257                 }
1258         }
1259 }
1260
1261 static unsigned *done_pbase_paths;
1262 static int done_pbase_paths_num;
1263 static int done_pbase_paths_alloc;
1264 static int done_pbase_path_pos(unsigned hash)
1265 {
1266         int lo = 0;
1267         int hi = done_pbase_paths_num;
1268         while (lo < hi) {
1269                 int mi = (hi + lo) / 2;
1270                 if (done_pbase_paths[mi] == hash)
1271                         return mi;
1272                 if (done_pbase_paths[mi] < hash)
1273                         hi = mi;
1274                 else
1275                         lo = mi + 1;
1276         }
1277         return -lo-1;
1278 }
1279
1280 static int check_pbase_path(unsigned hash)
1281 {
1282         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1283         if (0 <= pos)
1284                 return 1;
1285         pos = -pos - 1;
1286         ALLOC_GROW(done_pbase_paths,
1287                    done_pbase_paths_num + 1,
1288                    done_pbase_paths_alloc);
1289         done_pbase_paths_num++;
1290         if (pos < done_pbase_paths_num)
1291                 memmove(done_pbase_paths + pos + 1,
1292                         done_pbase_paths + pos,
1293                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1294         done_pbase_paths[pos] = hash;
1295         return 0;
1296 }
1297
1298 static void add_preferred_base_object(const char *name)
1299 {
1300         struct pbase_tree *it;
1301         int cmplen;
1302         unsigned hash = pack_name_hash(name);
1303
1304         if (!num_preferred_base || check_pbase_path(hash))
1305                 return;
1306
1307         cmplen = name_cmp_len(name);
1308         for (it = pbase_tree; it; it = it->next) {
1309                 if (cmplen == 0) {
1310                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1311                 }
1312                 else {
1313                         struct tree_desc tree;
1314                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1315                         add_pbase_object(&tree, name, cmplen, name);
1316                 }
1317         }
1318 }
1319
1320 static void add_preferred_base(unsigned char *sha1)
1321 {
1322         struct pbase_tree *it;
1323         void *data;
1324         unsigned long size;
1325         unsigned char tree_sha1[20];
1326
1327         if (window <= num_preferred_base++)
1328                 return;
1329
1330         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1331         if (!data)
1332                 return;
1333
1334         for (it = pbase_tree; it; it = it->next) {
1335                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1336                         free(data);
1337                         return;
1338                 }
1339         }
1340
1341         it = xcalloc(1, sizeof(*it));
1342         it->next = pbase_tree;
1343         pbase_tree = it;
1344
1345         hashcpy(it->pcache.sha1, tree_sha1);
1346         it->pcache.tree_data = data;
1347         it->pcache.tree_size = size;
1348 }
1349
1350 static void cleanup_preferred_base(void)
1351 {
1352         struct pbase_tree *it;
1353         unsigned i;
1354
1355         it = pbase_tree;
1356         pbase_tree = NULL;
1357         while (it) {
1358                 struct pbase_tree *this = it;
1359                 it = this->next;
1360                 free(this->pcache.tree_data);
1361                 free(this);
1362         }
1363
1364         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1365                 if (!pbase_tree_cache[i])
1366                         continue;
1367                 free(pbase_tree_cache[i]->tree_data);
1368                 free(pbase_tree_cache[i]);
1369                 pbase_tree_cache[i] = NULL;
1370         }
1371
1372         free(done_pbase_paths);
1373         done_pbase_paths = NULL;
1374         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1375 }
1376
1377 static void check_object(struct object_entry *entry)
1378 {
1379         if (entry->in_pack) {
1380                 struct packed_git *p = entry->in_pack;
1381                 struct pack_window *w_curs = NULL;
1382                 const unsigned char *base_ref = NULL;
1383                 struct object_entry *base_entry;
1384                 unsigned long used, used_0;
1385                 unsigned long avail;
1386                 off_t ofs;
1387                 unsigned char *buf, c;
1388
1389                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1390
1391                 /*
1392                  * We want in_pack_type even if we do not reuse delta
1393                  * since non-delta representations could still be reused.
1394                  */
1395                 used = unpack_object_header_buffer(buf, avail,
1396                                                    &entry->in_pack_type,
1397                                                    &entry->size);
1398                 if (used == 0)
1399                         goto give_up;
1400
1401                 /*
1402                  * Determine if this is a delta and if so whether we can
1403                  * reuse it or not.  Otherwise let's find out as cheaply as
1404                  * possible what the actual type and size for this object is.
1405                  */
1406                 switch (entry->in_pack_type) {
1407                 default:
1408                         /* Not a delta hence we've already got all we need. */
1409                         entry->type = entry->in_pack_type;
1410                         entry->in_pack_header_size = used;
1411                         if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1412                                 goto give_up;
1413                         unuse_pack(&w_curs);
1414                         return;
1415                 case OBJ_REF_DELTA:
1416                         if (reuse_delta && !entry->preferred_base)
1417                                 base_ref = use_pack(p, &w_curs,
1418                                                 entry->in_pack_offset + used, NULL);
1419                         entry->in_pack_header_size = used + 20;
1420                         break;
1421                 case OBJ_OFS_DELTA:
1422                         buf = use_pack(p, &w_curs,
1423                                        entry->in_pack_offset + used, NULL);
1424                         used_0 = 0;
1425                         c = buf[used_0++];
1426                         ofs = c & 127;
1427                         while (c & 128) {
1428                                 ofs += 1;
1429                                 if (!ofs || MSB(ofs, 7)) {
1430                                         error("delta base offset overflow in pack for %s",
1431                                               sha1_to_hex(entry->idx.sha1));
1432                                         goto give_up;
1433                                 }
1434                                 c = buf[used_0++];
1435                                 ofs = (ofs << 7) + (c & 127);
1436                         }
1437                         ofs = entry->in_pack_offset - ofs;
1438                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1439                                 error("delta base offset out of bound for %s",
1440                                       sha1_to_hex(entry->idx.sha1));
1441                                 goto give_up;
1442                         }
1443                         if (reuse_delta && !entry->preferred_base) {
1444                                 struct revindex_entry *revidx;
1445                                 revidx = find_pack_revindex(p, ofs);
1446                                 if (!revidx)
1447                                         goto give_up;
1448                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1449                         }
1450                         entry->in_pack_header_size = used + used_0;
1451                         break;
1452                 }
1453
1454                 if (base_ref && (base_entry = packlist_find(&to_pack, base_ref, NULL))) {
1455                         /*
1456                          * If base_ref was set above that means we wish to
1457                          * reuse delta data, and we even found that base
1458                          * in the list of objects we want to pack. Goodie!
1459                          *
1460                          * Depth value does not matter - find_deltas() will
1461                          * never consider reused delta as the base object to
1462                          * deltify other objects against, in order to avoid
1463                          * circular deltas.
1464                          */
1465                         entry->type = entry->in_pack_type;
1466                         entry->delta = base_entry;
1467                         entry->delta_size = entry->size;
1468                         entry->delta_sibling = base_entry->delta_child;
1469                         base_entry->delta_child = entry;
1470                         unuse_pack(&w_curs);
1471                         return;
1472                 }
1473
1474                 if (entry->type) {
1475                         /*
1476                          * This must be a delta and we already know what the
1477                          * final object type is.  Let's extract the actual
1478                          * object size from the delta header.
1479                          */
1480                         entry->size = get_size_from_delta(p, &w_curs,
1481                                         entry->in_pack_offset + entry->in_pack_header_size);
1482                         if (entry->size == 0)
1483                                 goto give_up;
1484                         unuse_pack(&w_curs);
1485                         return;
1486                 }
1487
1488                 /*
1489                  * No choice but to fall back to the recursive delta walk
1490                  * with sha1_object_info() to find about the object type
1491                  * at this point...
1492                  */
1493                 give_up:
1494                 unuse_pack(&w_curs);
1495         }
1496
1497         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1498         /*
1499          * The error condition is checked in prepare_pack().  This is
1500          * to permit a missing preferred base object to be ignored
1501          * as a preferred base.  Doing so can result in a larger
1502          * pack file, but the transfer will still take place.
1503          */
1504 }
1505
1506 static int pack_offset_sort(const void *_a, const void *_b)
1507 {
1508         const struct object_entry *a = *(struct object_entry **)_a;
1509         const struct object_entry *b = *(struct object_entry **)_b;
1510
1511         /* avoid filesystem trashing with loose objects */
1512         if (!a->in_pack && !b->in_pack)
1513                 return hashcmp(a->idx.sha1, b->idx.sha1);
1514
1515         if (a->in_pack < b->in_pack)
1516                 return -1;
1517         if (a->in_pack > b->in_pack)
1518                 return 1;
1519         return a->in_pack_offset < b->in_pack_offset ? -1 :
1520                         (a->in_pack_offset > b->in_pack_offset);
1521 }
1522
1523 /*
1524  * Drop an on-disk delta we were planning to reuse. Naively, this would
1525  * just involve blanking out the "delta" field, but we have to deal
1526  * with some extra book-keeping:
1527  *
1528  *   1. Removing ourselves from the delta_sibling linked list.
1529  *
1530  *   2. Updating our size/type to the non-delta representation. These were
1531  *      either not recorded initially (size) or overwritten with the delta type
1532  *      (type) when check_object() decided to reuse the delta.
1533  *
1534  *   3. Resetting our delta depth, as we are now a base object.
1535  */
1536 static void drop_reused_delta(struct object_entry *entry)
1537 {
1538         struct object_entry **p = &entry->delta->delta_child;
1539         struct object_info oi = OBJECT_INFO_INIT;
1540
1541         while (*p) {
1542                 if (*p == entry)
1543                         *p = (*p)->delta_sibling;
1544                 else
1545                         p = &(*p)->delta_sibling;
1546         }
1547         entry->delta = NULL;
1548         entry->depth = 0;
1549
1550         oi.sizep = &entry->size;
1551         oi.typep = &entry->type;
1552         if (packed_object_info(entry->in_pack, entry->in_pack_offset, &oi) < 0) {
1553                 /*
1554                  * We failed to get the info from this pack for some reason;
1555                  * fall back to sha1_object_info, which may find another copy.
1556                  * And if that fails, the error will be recorded in entry->type
1557                  * and dealt with in prepare_pack().
1558                  */
1559                 entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1560         }
1561 }
1562
1563 /*
1564  * Follow the chain of deltas from this entry onward, throwing away any links
1565  * that cause us to hit a cycle (as determined by the DFS state flags in
1566  * the entries).
1567  *
1568  * We also detect too-long reused chains that would violate our --depth
1569  * limit.
1570  */
1571 static void break_delta_chains(struct object_entry *entry)
1572 {
1573         /*
1574          * The actual depth of each object we will write is stored as an int,
1575          * as it cannot exceed our int "depth" limit. But before we break
1576          * changes based no that limit, we may potentially go as deep as the
1577          * number of objects, which is elsewhere bounded to a uint32_t.
1578          */
1579         uint32_t total_depth;
1580         struct object_entry *cur, *next;
1581
1582         for (cur = entry, total_depth = 0;
1583              cur;
1584              cur = cur->delta, total_depth++) {
1585                 if (cur->dfs_state == DFS_DONE) {
1586                         /*
1587                          * We've already seen this object and know it isn't
1588                          * part of a cycle. We do need to append its depth
1589                          * to our count.
1590                          */
1591                         total_depth += cur->depth;
1592                         break;
1593                 }
1594
1595                 /*
1596                  * We break cycles before looping, so an ACTIVE state (or any
1597                  * other cruft which made its way into the state variable)
1598                  * is a bug.
1599                  */
1600                 if (cur->dfs_state != DFS_NONE)
1601                         die("BUG: confusing delta dfs state in first pass: %d",
1602                             cur->dfs_state);
1603
1604                 /*
1605                  * Now we know this is the first time we've seen the object. If
1606                  * it's not a delta, we're done traversing, but we'll mark it
1607                  * done to save time on future traversals.
1608                  */
1609                 if (!cur->delta) {
1610                         cur->dfs_state = DFS_DONE;
1611                         break;
1612                 }
1613
1614                 /*
1615                  * Mark ourselves as active and see if the next step causes
1616                  * us to cycle to another active object. It's important to do
1617                  * this _before_ we loop, because it impacts where we make the
1618                  * cut, and thus how our total_depth counter works.
1619                  * E.g., We may see a partial loop like:
1620                  *
1621                  *   A -> B -> C -> D -> B
1622                  *
1623                  * Cutting B->C breaks the cycle. But now the depth of A is
1624                  * only 1, and our total_depth counter is at 3. The size of the
1625                  * error is always one less than the size of the cycle we
1626                  * broke. Commits C and D were "lost" from A's chain.
1627                  *
1628                  * If we instead cut D->B, then the depth of A is correct at 3.
1629                  * We keep all commits in the chain that we examined.
1630                  */
1631                 cur->dfs_state = DFS_ACTIVE;
1632                 if (cur->delta->dfs_state == DFS_ACTIVE) {
1633                         drop_reused_delta(cur);
1634                         cur->dfs_state = DFS_DONE;
1635                         break;
1636                 }
1637         }
1638
1639         /*
1640          * And now that we've gone all the way to the bottom of the chain, we
1641          * need to clear the active flags and set the depth fields as
1642          * appropriate. Unlike the loop above, which can quit when it drops a
1643          * delta, we need to keep going to look for more depth cuts. So we need
1644          * an extra "next" pointer to keep going after we reset cur->delta.
1645          */
1646         for (cur = entry; cur; cur = next) {
1647                 next = cur->delta;
1648
1649                 /*
1650                  * We should have a chain of zero or more ACTIVE states down to
1651                  * a final DONE. We can quit after the DONE, because either it
1652                  * has no bases, or we've already handled them in a previous
1653                  * call.
1654                  */
1655                 if (cur->dfs_state == DFS_DONE)
1656                         break;
1657                 else if (cur->dfs_state != DFS_ACTIVE)
1658                         die("BUG: confusing delta dfs state in second pass: %d",
1659                             cur->dfs_state);
1660
1661                 /*
1662                  * If the total_depth is more than depth, then we need to snip
1663                  * the chain into two or more smaller chains that don't exceed
1664                  * the maximum depth. Most of the resulting chains will contain
1665                  * (depth + 1) entries (i.e., depth deltas plus one base), and
1666                  * the last chain (i.e., the one containing entry) will contain
1667                  * whatever entries are left over, namely
1668                  * (total_depth % (depth + 1)) of them.
1669                  *
1670                  * Since we are iterating towards decreasing depth, we need to
1671                  * decrement total_depth as we go, and we need to write to the
1672                  * entry what its final depth will be after all of the
1673                  * snipping. Since we're snipping into chains of length (depth
1674                  * + 1) entries, the final depth of an entry will be its
1675                  * original depth modulo (depth + 1). Any time we encounter an
1676                  * entry whose final depth is supposed to be zero, we snip it
1677                  * from its delta base, thereby making it so.
1678                  */
1679                 cur->depth = (total_depth--) % (depth + 1);
1680                 if (!cur->depth)
1681                         drop_reused_delta(cur);
1682
1683                 cur->dfs_state = DFS_DONE;
1684         }
1685 }
1686
1687 static void get_object_details(void)
1688 {
1689         uint32_t i;
1690         struct object_entry **sorted_by_offset;
1691
1692         sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
1693         for (i = 0; i < to_pack.nr_objects; i++)
1694                 sorted_by_offset[i] = to_pack.objects + i;
1695         QSORT(sorted_by_offset, to_pack.nr_objects, pack_offset_sort);
1696
1697         for (i = 0; i < to_pack.nr_objects; i++) {
1698                 struct object_entry *entry = sorted_by_offset[i];
1699                 check_object(entry);
1700                 if (big_file_threshold < entry->size)
1701                         entry->no_try_delta = 1;
1702         }
1703
1704         /*
1705          * This must happen in a second pass, since we rely on the delta
1706          * information for the whole list being completed.
1707          */
1708         for (i = 0; i < to_pack.nr_objects; i++)
1709                 break_delta_chains(&to_pack.objects[i]);
1710
1711         free(sorted_by_offset);
1712 }
1713
1714 /*
1715  * We search for deltas in a list sorted by type, by filename hash, and then
1716  * by size, so that we see progressively smaller and smaller files.
1717  * That's because we prefer deltas to be from the bigger file
1718  * to the smaller -- deletes are potentially cheaper, but perhaps
1719  * more importantly, the bigger file is likely the more recent
1720  * one.  The deepest deltas are therefore the oldest objects which are
1721  * less susceptible to be accessed often.
1722  */
1723 static int type_size_sort(const void *_a, const void *_b)
1724 {
1725         const struct object_entry *a = *(struct object_entry **)_a;
1726         const struct object_entry *b = *(struct object_entry **)_b;
1727
1728         if (a->type > b->type)
1729                 return -1;
1730         if (a->type < b->type)
1731                 return 1;
1732         if (a->hash > b->hash)
1733                 return -1;
1734         if (a->hash < b->hash)
1735                 return 1;
1736         if (a->preferred_base > b->preferred_base)
1737                 return -1;
1738         if (a->preferred_base < b->preferred_base)
1739                 return 1;
1740         if (a->size > b->size)
1741                 return -1;
1742         if (a->size < b->size)
1743                 return 1;
1744         return a < b ? -1 : (a > b);  /* newest first */
1745 }
1746
1747 struct unpacked {
1748         struct object_entry *entry;
1749         void *data;
1750         struct delta_index *index;
1751         unsigned depth;
1752 };
1753
1754 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1755                            unsigned long delta_size)
1756 {
1757         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1758                 return 0;
1759
1760         if (delta_size < cache_max_small_delta_size)
1761                 return 1;
1762
1763         /* cache delta, if objects are large enough compared to delta size */
1764         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1765                 return 1;
1766
1767         return 0;
1768 }
1769
1770 #ifndef NO_PTHREADS
1771
1772 static pthread_mutex_t read_mutex;
1773 #define read_lock()             pthread_mutex_lock(&read_mutex)
1774 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1775
1776 static pthread_mutex_t cache_mutex;
1777 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1778 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1779
1780 static pthread_mutex_t progress_mutex;
1781 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1782 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1783
1784 #else
1785
1786 #define read_lock()             (void)0
1787 #define read_unlock()           (void)0
1788 #define cache_lock()            (void)0
1789 #define cache_unlock()          (void)0
1790 #define progress_lock()         (void)0
1791 #define progress_unlock()       (void)0
1792
1793 #endif
1794
1795 static int try_delta(struct unpacked *trg, struct unpacked *src,
1796                      unsigned max_depth, unsigned long *mem_usage)
1797 {
1798         struct object_entry *trg_entry = trg->entry;
1799         struct object_entry *src_entry = src->entry;
1800         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1801         unsigned ref_depth;
1802         enum object_type type;
1803         void *delta_buf;
1804
1805         /* Don't bother doing diffs between different types */
1806         if (trg_entry->type != src_entry->type)
1807                 return -1;
1808
1809         /*
1810          * We do not bother to try a delta that we discarded on an
1811          * earlier try, but only when reusing delta data.  Note that
1812          * src_entry that is marked as the preferred_base should always
1813          * be considered, as even if we produce a suboptimal delta against
1814          * it, we will still save the transfer cost, as we already know
1815          * the other side has it and we won't send src_entry at all.
1816          */
1817         if (reuse_delta && trg_entry->in_pack &&
1818             trg_entry->in_pack == src_entry->in_pack &&
1819             !src_entry->preferred_base &&
1820             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1821             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1822                 return 0;
1823
1824         /* Let's not bust the allowed depth. */
1825         if (src->depth >= max_depth)
1826                 return 0;
1827
1828         /* Now some size filtering heuristics. */
1829         trg_size = trg_entry->size;
1830         if (!trg_entry->delta) {
1831                 max_size = trg_size/2 - 20;
1832                 ref_depth = 1;
1833         } else {
1834                 max_size = trg_entry->delta_size;
1835                 ref_depth = trg->depth;
1836         }
1837         max_size = (uint64_t)max_size * (max_depth - src->depth) /
1838                                                 (max_depth - ref_depth + 1);
1839         if (max_size == 0)
1840                 return 0;
1841         src_size = src_entry->size;
1842         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1843         if (sizediff >= max_size)
1844                 return 0;
1845         if (trg_size < src_size / 32)
1846                 return 0;
1847
1848         /* Load data if not already done */
1849         if (!trg->data) {
1850                 read_lock();
1851                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1852                 read_unlock();
1853                 if (!trg->data)
1854                         die("object %s cannot be read",
1855                             sha1_to_hex(trg_entry->idx.sha1));
1856                 if (sz != trg_size)
1857                         die("object %s inconsistent object length (%lu vs %lu)",
1858                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1859                 *mem_usage += sz;
1860         }
1861         if (!src->data) {
1862                 read_lock();
1863                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1864                 read_unlock();
1865                 if (!src->data) {
1866                         if (src_entry->preferred_base) {
1867                                 static int warned = 0;
1868                                 if (!warned++)
1869                                         warning("object %s cannot be read",
1870                                                 sha1_to_hex(src_entry->idx.sha1));
1871                                 /*
1872                                  * Those objects are not included in the
1873                                  * resulting pack.  Be resilient and ignore
1874                                  * them if they can't be read, in case the
1875                                  * pack could be created nevertheless.
1876                                  */
1877                                 return 0;
1878                         }
1879                         die("object %s cannot be read",
1880                             sha1_to_hex(src_entry->idx.sha1));
1881                 }
1882                 if (sz != src_size)
1883                         die("object %s inconsistent object length (%lu vs %lu)",
1884                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1885                 *mem_usage += sz;
1886         }
1887         if (!src->index) {
1888                 src->index = create_delta_index(src->data, src_size);
1889                 if (!src->index) {
1890                         static int warned = 0;
1891                         if (!warned++)
1892                                 warning("suboptimal pack - out of memory");
1893                         return 0;
1894                 }
1895                 *mem_usage += sizeof_delta_index(src->index);
1896         }
1897
1898         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1899         if (!delta_buf)
1900                 return 0;
1901
1902         if (trg_entry->delta) {
1903                 /* Prefer only shallower same-sized deltas. */
1904                 if (delta_size == trg_entry->delta_size &&
1905                     src->depth + 1 >= trg->depth) {
1906                         free(delta_buf);
1907                         return 0;
1908                 }
1909         }
1910
1911         /*
1912          * Handle memory allocation outside of the cache
1913          * accounting lock.  Compiler will optimize the strangeness
1914          * away when NO_PTHREADS is defined.
1915          */
1916         free(trg_entry->delta_data);
1917         cache_lock();
1918         if (trg_entry->delta_data) {
1919                 delta_cache_size -= trg_entry->delta_size;
1920                 trg_entry->delta_data = NULL;
1921         }
1922         if (delta_cacheable(src_size, trg_size, delta_size)) {
1923                 delta_cache_size += delta_size;
1924                 cache_unlock();
1925                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1926         } else {
1927                 cache_unlock();
1928                 free(delta_buf);
1929         }
1930
1931         trg_entry->delta = src_entry;
1932         trg_entry->delta_size = delta_size;
1933         trg->depth = src->depth + 1;
1934
1935         return 1;
1936 }
1937
1938 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1939 {
1940         struct object_entry *child = me->delta_child;
1941         unsigned int m = n;
1942         while (child) {
1943                 unsigned int c = check_delta_limit(child, n + 1);
1944                 if (m < c)
1945                         m = c;
1946                 child = child->delta_sibling;
1947         }
1948         return m;
1949 }
1950
1951 static unsigned long free_unpacked(struct unpacked *n)
1952 {
1953         unsigned long freed_mem = sizeof_delta_index(n->index);
1954         free_delta_index(n->index);
1955         n->index = NULL;
1956         if (n->data) {
1957                 freed_mem += n->entry->size;
1958                 free(n->data);
1959                 n->data = NULL;
1960         }
1961         n->entry = NULL;
1962         n->depth = 0;
1963         return freed_mem;
1964 }
1965
1966 static void find_deltas(struct object_entry **list, unsigned *list_size,
1967                         int window, int depth, unsigned *processed)
1968 {
1969         uint32_t i, idx = 0, count = 0;
1970         struct unpacked *array;
1971         unsigned long mem_usage = 0;
1972
1973         array = xcalloc(window, sizeof(struct unpacked));
1974
1975         for (;;) {
1976                 struct object_entry *entry;
1977                 struct unpacked *n = array + idx;
1978                 int j, max_depth, best_base = -1;
1979
1980                 progress_lock();
1981                 if (!*list_size) {
1982                         progress_unlock();
1983                         break;
1984                 }
1985                 entry = *list++;
1986                 (*list_size)--;
1987                 if (!entry->preferred_base) {
1988                         (*processed)++;
1989                         display_progress(progress_state, *processed);
1990                 }
1991                 progress_unlock();
1992
1993                 mem_usage -= free_unpacked(n);
1994                 n->entry = entry;
1995
1996                 while (window_memory_limit &&
1997                        mem_usage > window_memory_limit &&
1998                        count > 1) {
1999                         uint32_t tail = (idx + window - count) % window;
2000                         mem_usage -= free_unpacked(array + tail);
2001                         count--;
2002                 }
2003
2004                 /* We do not compute delta to *create* objects we are not
2005                  * going to pack.
2006                  */
2007                 if (entry->preferred_base)
2008                         goto next;
2009
2010                 /*
2011                  * If the current object is at pack edge, take the depth the
2012                  * objects that depend on the current object into account
2013                  * otherwise they would become too deep.
2014                  */
2015                 max_depth = depth;
2016                 if (entry->delta_child) {
2017                         max_depth -= check_delta_limit(entry, 0);
2018                         if (max_depth <= 0)
2019                                 goto next;
2020                 }
2021
2022                 j = window;
2023                 while (--j > 0) {
2024                         int ret;
2025                         uint32_t other_idx = idx + j;
2026                         struct unpacked *m;
2027                         if (other_idx >= window)
2028                                 other_idx -= window;
2029                         m = array + other_idx;
2030                         if (!m->entry)
2031                                 break;
2032                         ret = try_delta(n, m, max_depth, &mem_usage);
2033                         if (ret < 0)
2034                                 break;
2035                         else if (ret > 0)
2036                                 best_base = other_idx;
2037                 }
2038
2039                 /*
2040                  * If we decided to cache the delta data, then it is best
2041                  * to compress it right away.  First because we have to do
2042                  * it anyway, and doing it here while we're threaded will
2043                  * save a lot of time in the non threaded write phase,
2044                  * as well as allow for caching more deltas within
2045                  * the same cache size limit.
2046                  * ...
2047                  * But only if not writing to stdout, since in that case
2048                  * the network is most likely throttling writes anyway,
2049                  * and therefore it is best to go to the write phase ASAP
2050                  * instead, as we can afford spending more time compressing
2051                  * between writes at that moment.
2052                  */
2053                 if (entry->delta_data && !pack_to_stdout) {
2054                         entry->z_delta_size = do_compress(&entry->delta_data,
2055                                                           entry->delta_size);
2056                         cache_lock();
2057                         delta_cache_size -= entry->delta_size;
2058                         delta_cache_size += entry->z_delta_size;
2059                         cache_unlock();
2060                 }
2061
2062                 /* if we made n a delta, and if n is already at max
2063                  * depth, leaving it in the window is pointless.  we
2064                  * should evict it first.
2065                  */
2066                 if (entry->delta && max_depth <= n->depth)
2067                         continue;
2068
2069                 /*
2070                  * Move the best delta base up in the window, after the
2071                  * currently deltified object, to keep it longer.  It will
2072                  * be the first base object to be attempted next.
2073                  */
2074                 if (entry->delta) {
2075                         struct unpacked swap = array[best_base];
2076                         int dist = (window + idx - best_base) % window;
2077                         int dst = best_base;
2078                         while (dist--) {
2079                                 int src = (dst + 1) % window;
2080                                 array[dst] = array[src];
2081                                 dst = src;
2082                         }
2083                         array[dst] = swap;
2084                 }
2085
2086                 next:
2087                 idx++;
2088                 if (count + 1 < window)
2089                         count++;
2090                 if (idx >= window)
2091                         idx = 0;
2092         }
2093
2094         for (i = 0; i < window; ++i) {
2095                 free_delta_index(array[i].index);
2096                 free(array[i].data);
2097         }
2098         free(array);
2099 }
2100
2101 #ifndef NO_PTHREADS
2102
2103 static void try_to_free_from_threads(size_t size)
2104 {
2105         read_lock();
2106         release_pack_memory(size);
2107         read_unlock();
2108 }
2109
2110 static try_to_free_t old_try_to_free_routine;
2111
2112 /*
2113  * The main thread waits on the condition that (at least) one of the workers
2114  * has stopped working (which is indicated in the .working member of
2115  * struct thread_params).
2116  * When a work thread has completed its work, it sets .working to 0 and
2117  * signals the main thread and waits on the condition that .data_ready
2118  * becomes 1.
2119  */
2120
2121 struct thread_params {
2122         pthread_t thread;
2123         struct object_entry **list;
2124         unsigned list_size;
2125         unsigned remaining;
2126         int window;
2127         int depth;
2128         int working;
2129         int data_ready;
2130         pthread_mutex_t mutex;
2131         pthread_cond_t cond;
2132         unsigned *processed;
2133 };
2134
2135 static pthread_cond_t progress_cond;
2136
2137 /*
2138  * Mutex and conditional variable can't be statically-initialized on Windows.
2139  */
2140 static void init_threaded_search(void)
2141 {
2142         init_recursive_mutex(&read_mutex);
2143         pthread_mutex_init(&cache_mutex, NULL);
2144         pthread_mutex_init(&progress_mutex, NULL);
2145         pthread_cond_init(&progress_cond, NULL);
2146         old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
2147 }
2148
2149 static void cleanup_threaded_search(void)
2150 {
2151         set_try_to_free_routine(old_try_to_free_routine);
2152         pthread_cond_destroy(&progress_cond);
2153         pthread_mutex_destroy(&read_mutex);
2154         pthread_mutex_destroy(&cache_mutex);
2155         pthread_mutex_destroy(&progress_mutex);
2156 }
2157
2158 static void *threaded_find_deltas(void *arg)
2159 {
2160         struct thread_params *me = arg;
2161
2162         while (me->remaining) {
2163                 find_deltas(me->list, &me->remaining,
2164                             me->window, me->depth, me->processed);
2165
2166                 progress_lock();
2167                 me->working = 0;
2168                 pthread_cond_signal(&progress_cond);
2169                 progress_unlock();
2170
2171                 /*
2172                  * We must not set ->data_ready before we wait on the
2173                  * condition because the main thread may have set it to 1
2174                  * before we get here. In order to be sure that new
2175                  * work is available if we see 1 in ->data_ready, it
2176                  * was initialized to 0 before this thread was spawned
2177                  * and we reset it to 0 right away.
2178                  */
2179                 pthread_mutex_lock(&me->mutex);
2180                 while (!me->data_ready)
2181                         pthread_cond_wait(&me->cond, &me->mutex);
2182                 me->data_ready = 0;
2183                 pthread_mutex_unlock(&me->mutex);
2184         }
2185         /* leave ->working 1 so that this doesn't get more work assigned */
2186         return NULL;
2187 }
2188
2189 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
2190                            int window, int depth, unsigned *processed)
2191 {
2192         struct thread_params *p;
2193         int i, ret, active_threads = 0;
2194
2195         init_threaded_search();
2196
2197         if (delta_search_threads <= 1) {
2198                 find_deltas(list, &list_size, window, depth, processed);
2199                 cleanup_threaded_search();
2200                 return;
2201         }
2202         if (progress > pack_to_stdout)
2203                 fprintf(stderr, "Delta compression using up to %d threads.\n",
2204                                 delta_search_threads);
2205         p = xcalloc(delta_search_threads, sizeof(*p));
2206
2207         /* Partition the work amongst work threads. */
2208         for (i = 0; i < delta_search_threads; i++) {
2209                 unsigned sub_size = list_size / (delta_search_threads - i);
2210
2211                 /* don't use too small segments or no deltas will be found */
2212                 if (sub_size < 2*window && i+1 < delta_search_threads)
2213                         sub_size = 0;
2214
2215                 p[i].window = window;
2216                 p[i].depth = depth;
2217                 p[i].processed = processed;
2218                 p[i].working = 1;
2219                 p[i].data_ready = 0;
2220
2221                 /* try to split chunks on "path" boundaries */
2222                 while (sub_size && sub_size < list_size &&
2223                        list[sub_size]->hash &&
2224                        list[sub_size]->hash == list[sub_size-1]->hash)
2225                         sub_size++;
2226
2227                 p[i].list = list;
2228                 p[i].list_size = sub_size;
2229                 p[i].remaining = sub_size;
2230
2231                 list += sub_size;
2232                 list_size -= sub_size;
2233         }
2234
2235         /* Start work threads. */
2236         for (i = 0; i < delta_search_threads; i++) {
2237                 if (!p[i].list_size)
2238                         continue;
2239                 pthread_mutex_init(&p[i].mutex, NULL);
2240                 pthread_cond_init(&p[i].cond, NULL);
2241                 ret = pthread_create(&p[i].thread, NULL,
2242                                      threaded_find_deltas, &p[i]);
2243                 if (ret)
2244                         die("unable to create thread: %s", strerror(ret));
2245                 active_threads++;
2246         }
2247
2248         /*
2249          * Now let's wait for work completion.  Each time a thread is done
2250          * with its work, we steal half of the remaining work from the
2251          * thread with the largest number of unprocessed objects and give
2252          * it to that newly idle thread.  This ensure good load balancing
2253          * until the remaining object list segments are simply too short
2254          * to be worth splitting anymore.
2255          */
2256         while (active_threads) {
2257                 struct thread_params *target = NULL;
2258                 struct thread_params *victim = NULL;
2259                 unsigned sub_size = 0;
2260
2261                 progress_lock();
2262                 for (;;) {
2263                         for (i = 0; !target && i < delta_search_threads; i++)
2264                                 if (!p[i].working)
2265                                         target = &p[i];
2266                         if (target)
2267                                 break;
2268                         pthread_cond_wait(&progress_cond, &progress_mutex);
2269                 }
2270
2271                 for (i = 0; i < delta_search_threads; i++)
2272                         if (p[i].remaining > 2*window &&
2273                             (!victim || victim->remaining < p[i].remaining))
2274                                 victim = &p[i];
2275                 if (victim) {
2276                         sub_size = victim->remaining / 2;
2277                         list = victim->list + victim->list_size - sub_size;
2278                         while (sub_size && list[0]->hash &&
2279                                list[0]->hash == list[-1]->hash) {
2280                                 list++;
2281                                 sub_size--;
2282                         }
2283                         if (!sub_size) {
2284                                 /*
2285                                  * It is possible for some "paths" to have
2286                                  * so many objects that no hash boundary
2287                                  * might be found.  Let's just steal the
2288                                  * exact half in that case.
2289                                  */
2290                                 sub_size = victim->remaining / 2;
2291                                 list -= sub_size;
2292                         }
2293                         target->list = list;
2294                         victim->list_size -= sub_size;
2295                         victim->remaining -= sub_size;
2296                 }
2297                 target->list_size = sub_size;
2298                 target->remaining = sub_size;
2299                 target->working = 1;
2300                 progress_unlock();
2301
2302                 pthread_mutex_lock(&target->mutex);
2303                 target->data_ready = 1;
2304                 pthread_cond_signal(&target->cond);
2305                 pthread_mutex_unlock(&target->mutex);
2306
2307                 if (!sub_size) {
2308                         pthread_join(target->thread, NULL);
2309                         pthread_cond_destroy(&target->cond);
2310                         pthread_mutex_destroy(&target->mutex);
2311                         active_threads--;
2312                 }
2313         }
2314         cleanup_threaded_search();
2315         free(p);
2316 }
2317
2318 #else
2319 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
2320 #endif
2321
2322 static void add_tag_chain(const struct object_id *oid)
2323 {
2324         struct tag *tag;
2325
2326         /*
2327          * We catch duplicates already in add_object_entry(), but we'd
2328          * prefer to do this extra check to avoid having to parse the
2329          * tag at all if we already know that it's being packed (e.g., if
2330          * it was included via bitmaps, we would not have parsed it
2331          * previously).
2332          */
2333         if (packlist_find(&to_pack, oid->hash, NULL))
2334                 return;
2335
2336         tag = lookup_tag(oid->hash);
2337         while (1) {
2338                 if (!tag || parse_tag(tag) || !tag->tagged)
2339                         die("unable to pack objects reachable from tag %s",
2340                             oid_to_hex(oid));
2341
2342                 add_object_entry(tag->object.oid.hash, OBJ_TAG, NULL, 0);
2343
2344                 if (tag->tagged->type != OBJ_TAG)
2345                         return;
2346
2347                 tag = (struct tag *)tag->tagged;
2348         }
2349 }
2350
2351 static int add_ref_tag(const char *path, const struct object_id *oid, int flag, void *cb_data)
2352 {
2353         struct object_id peeled;
2354
2355         if (starts_with(path, "refs/tags/") && /* is a tag? */
2356             !peel_ref(path, peeled.hash)    && /* peelable? */
2357             packlist_find(&to_pack, peeled.hash, NULL))      /* object packed? */
2358                 add_tag_chain(oid);
2359         return 0;
2360 }
2361
2362 static void prepare_pack(int window, int depth)
2363 {
2364         struct object_entry **delta_list;
2365         uint32_t i, nr_deltas;
2366         unsigned n;
2367
2368         get_object_details();
2369
2370         /*
2371          * If we're locally repacking then we need to be doubly careful
2372          * from now on in order to make sure no stealth corruption gets
2373          * propagated to the new pack.  Clients receiving streamed packs
2374          * should validate everything they get anyway so no need to incur
2375          * the additional cost here in that case.
2376          */
2377         if (!pack_to_stdout)
2378                 do_check_packed_object_crc = 1;
2379
2380         if (!to_pack.nr_objects || !window || !depth)
2381                 return;
2382
2383         ALLOC_ARRAY(delta_list, to_pack.nr_objects);
2384         nr_deltas = n = 0;
2385
2386         for (i = 0; i < to_pack.nr_objects; i++) {
2387                 struct object_entry *entry = to_pack.objects + i;
2388
2389                 if (entry->delta)
2390                         /* This happens if we decided to reuse existing
2391                          * delta from a pack.  "reuse_delta &&" is implied.
2392                          */
2393                         continue;
2394
2395                 if (entry->size < 50)
2396                         continue;
2397
2398                 if (entry->no_try_delta)
2399                         continue;
2400
2401                 if (!entry->preferred_base) {
2402                         nr_deltas++;
2403                         if (entry->type < 0)
2404                                 die("unable to get type of object %s",
2405                                     sha1_to_hex(entry->idx.sha1));
2406                 } else {
2407                         if (entry->type < 0) {
2408                                 /*
2409                                  * This object is not found, but we
2410                                  * don't have to include it anyway.
2411                                  */
2412                                 continue;
2413                         }
2414                 }
2415
2416                 delta_list[n++] = entry;
2417         }
2418
2419         if (nr_deltas && n > 1) {
2420                 unsigned nr_done = 0;
2421                 if (progress)
2422                         progress_state = start_progress(_("Compressing objects"),
2423                                                         nr_deltas);
2424                 QSORT(delta_list, n, type_size_sort);
2425                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2426                 stop_progress(&progress_state);
2427                 if (nr_done != nr_deltas)
2428                         die("inconsistency with delta count");
2429         }
2430         free(delta_list);
2431 }
2432
2433 static int git_pack_config(const char *k, const char *v, void *cb)
2434 {
2435         if (!strcmp(k, "pack.window")) {
2436                 window = git_config_int(k, v);
2437                 return 0;
2438         }
2439         if (!strcmp(k, "pack.windowmemory")) {
2440                 window_memory_limit = git_config_ulong(k, v);
2441                 return 0;
2442         }
2443         if (!strcmp(k, "pack.depth")) {
2444                 depth = git_config_int(k, v);
2445                 return 0;
2446         }
2447         if (!strcmp(k, "pack.deltacachesize")) {
2448                 max_delta_cache_size = git_config_int(k, v);
2449                 return 0;
2450         }
2451         if (!strcmp(k, "pack.deltacachelimit")) {
2452                 cache_max_small_delta_size = git_config_int(k, v);
2453                 return 0;
2454         }
2455         if (!strcmp(k, "pack.writebitmaphashcache")) {
2456                 if (git_config_bool(k, v))
2457                         write_bitmap_options |= BITMAP_OPT_HASH_CACHE;
2458                 else
2459                         write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
2460         }
2461         if (!strcmp(k, "pack.usebitmaps")) {
2462                 use_bitmap_index_default = git_config_bool(k, v);
2463                 return 0;
2464         }
2465         if (!strcmp(k, "pack.threads")) {
2466                 delta_search_threads = git_config_int(k, v);
2467                 if (delta_search_threads < 0)
2468                         die("invalid number of threads specified (%d)",
2469                             delta_search_threads);
2470 #ifdef NO_PTHREADS
2471                 if (delta_search_threads != 1)
2472                         warning("no threads support, ignoring %s", k);
2473 #endif
2474                 return 0;
2475         }
2476         if (!strcmp(k, "pack.indexversion")) {
2477                 pack_idx_opts.version = git_config_int(k, v);
2478                 if (pack_idx_opts.version > 2)
2479                         die("bad pack.indexversion=%"PRIu32,
2480                             pack_idx_opts.version);
2481                 return 0;
2482         }
2483         return git_default_config(k, v, cb);
2484 }
2485
2486 static void read_object_list_from_stdin(void)
2487 {
2488         char line[40 + 1 + PATH_MAX + 2];
2489         unsigned char sha1[20];
2490
2491         for (;;) {
2492                 if (!fgets(line, sizeof(line), stdin)) {
2493                         if (feof(stdin))
2494                                 break;
2495                         if (!ferror(stdin))
2496                                 die("fgets returned NULL, not EOF, not error!");
2497                         if (errno != EINTR)
2498                                 die_errno("fgets");
2499                         clearerr(stdin);
2500                         continue;
2501                 }
2502                 if (line[0] == '-') {
2503                         if (get_sha1_hex(line+1, sha1))
2504                                 die("expected edge sha1, got garbage:\n %s",
2505                                     line);
2506                         add_preferred_base(sha1);
2507                         continue;
2508                 }
2509                 if (get_sha1_hex(line, sha1))
2510                         die("expected sha1, got garbage:\n %s", line);
2511
2512                 add_preferred_base_object(line+41);
2513                 add_object_entry(sha1, 0, line+41, 0);
2514         }
2515 }
2516
2517 #define OBJECT_ADDED (1u<<20)
2518
2519 static void show_commit(struct commit *commit, void *data)
2520 {
2521         add_object_entry(commit->object.oid.hash, OBJ_COMMIT, NULL, 0);
2522         commit->object.flags |= OBJECT_ADDED;
2523
2524         if (write_bitmap_index)
2525                 index_commit_for_bitmap(commit);
2526 }
2527
2528 static void show_object(struct object *obj, const char *name, void *data)
2529 {
2530         add_preferred_base_object(name);
2531         add_object_entry(obj->oid.hash, obj->type, name, 0);
2532         obj->flags |= OBJECT_ADDED;
2533 }
2534
2535 static void show_edge(struct commit *commit)
2536 {
2537         add_preferred_base(commit->object.oid.hash);
2538 }
2539
2540 struct in_pack_object {
2541         off_t offset;
2542         struct object *object;
2543 };
2544
2545 struct in_pack {
2546         int alloc;
2547         int nr;
2548         struct in_pack_object *array;
2549 };
2550
2551 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2552 {
2553         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->oid.hash, p);
2554         in_pack->array[in_pack->nr].object = object;
2555         in_pack->nr++;
2556 }
2557
2558 /*
2559  * Compare the objects in the offset order, in order to emulate the
2560  * "git rev-list --objects" output that produced the pack originally.
2561  */
2562 static int ofscmp(const void *a_, const void *b_)
2563 {
2564         struct in_pack_object *a = (struct in_pack_object *)a_;
2565         struct in_pack_object *b = (struct in_pack_object *)b_;
2566
2567         if (a->offset < b->offset)
2568                 return -1;
2569         else if (a->offset > b->offset)
2570                 return 1;
2571         else
2572                 return oidcmp(&a->object->oid, &b->object->oid);
2573 }
2574
2575 static void add_objects_in_unpacked_packs(struct rev_info *revs)
2576 {
2577         struct packed_git *p;
2578         struct in_pack in_pack;
2579         uint32_t i;
2580
2581         memset(&in_pack, 0, sizeof(in_pack));
2582
2583         for (p = packed_git; p; p = p->next) {
2584                 const unsigned char *sha1;
2585                 struct object *o;
2586
2587                 if (!p->pack_local || p->pack_keep)
2588                         continue;
2589                 if (open_pack_index(p))
2590                         die("cannot open pack index");
2591
2592                 ALLOC_GROW(in_pack.array,
2593                            in_pack.nr + p->num_objects,
2594                            in_pack.alloc);
2595
2596                 for (i = 0; i < p->num_objects; i++) {
2597                         sha1 = nth_packed_object_sha1(p, i);
2598                         o = lookup_unknown_object(sha1);
2599                         if (!(o->flags & OBJECT_ADDED))
2600                                 mark_in_pack_object(o, p, &in_pack);
2601                         o->flags |= OBJECT_ADDED;
2602                 }
2603         }
2604
2605         if (in_pack.nr) {
2606                 QSORT(in_pack.array, in_pack.nr, ofscmp);
2607                 for (i = 0; i < in_pack.nr; i++) {
2608                         struct object *o = in_pack.array[i].object;
2609                         add_object_entry(o->oid.hash, o->type, "", 0);
2610                 }
2611         }
2612         free(in_pack.array);
2613 }
2614
2615 static int add_loose_object(const unsigned char *sha1, const char *path,
2616                             void *data)
2617 {
2618         enum object_type type = sha1_object_info(sha1, NULL);
2619
2620         if (type < 0) {
2621                 warning("loose object at %s could not be examined", path);
2622                 return 0;
2623         }
2624
2625         add_object_entry(sha1, type, "", 0);
2626         return 0;
2627 }
2628
2629 /*
2630  * We actually don't even have to worry about reachability here.
2631  * add_object_entry will weed out duplicates, so we just add every
2632  * loose object we find.
2633  */
2634 static void add_unreachable_loose_objects(void)
2635 {
2636         for_each_loose_file_in_objdir(get_object_directory(),
2637                                       add_loose_object,
2638                                       NULL, NULL, NULL);
2639 }
2640
2641 static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
2642 {
2643         static struct packed_git *last_found = (void *)1;
2644         struct packed_git *p;
2645
2646         p = (last_found != (void *)1) ? last_found : packed_git;
2647
2648         while (p) {
2649                 if ((!p->pack_local || p->pack_keep) &&
2650                         find_pack_entry_one(sha1, p)) {
2651                         last_found = p;
2652                         return 1;
2653                 }
2654                 if (p == last_found)
2655                         p = packed_git;
2656                 else
2657                         p = p->next;
2658                 if (p == last_found)
2659                         p = p->next;
2660         }
2661         return 0;
2662 }
2663
2664 /*
2665  * Store a list of sha1s that are should not be discarded
2666  * because they are either written too recently, or are
2667  * reachable from another object that was.
2668  *
2669  * This is filled by get_object_list.
2670  */
2671 static struct sha1_array recent_objects;
2672
2673 static int loosened_object_can_be_discarded(const unsigned char *sha1,
2674                                             unsigned long mtime)
2675 {
2676         if (!unpack_unreachable_expiration)
2677                 return 0;
2678         if (mtime > unpack_unreachable_expiration)
2679                 return 0;
2680         if (sha1_array_lookup(&recent_objects, sha1) >= 0)
2681                 return 0;
2682         return 1;
2683 }
2684
2685 static void loosen_unused_packed_objects(struct rev_info *revs)
2686 {
2687         struct packed_git *p;
2688         uint32_t i;
2689         const unsigned char *sha1;
2690
2691         for (p = packed_git; p; p = p->next) {
2692                 if (!p->pack_local || p->pack_keep)
2693                         continue;
2694
2695                 if (open_pack_index(p))
2696                         die("cannot open pack index");
2697
2698                 for (i = 0; i < p->num_objects; i++) {
2699                         sha1 = nth_packed_object_sha1(p, i);
2700                         if (!packlist_find(&to_pack, sha1, NULL) &&
2701                             !has_sha1_pack_kept_or_nonlocal(sha1) &&
2702                             !loosened_object_can_be_discarded(sha1, p->mtime))
2703                                 if (force_object_loose(sha1, p->mtime))
2704                                         die("unable to force loose object");
2705                 }
2706         }
2707 }
2708
2709 /*
2710  * This tracks any options which pack-reuse code expects to be on, or which a
2711  * reader of the pack might not understand, and which would therefore prevent
2712  * blind reuse of what we have on disk.
2713  */
2714 static int pack_options_allow_reuse(void)
2715 {
2716         return pack_to_stdout && allow_ofs_delta;
2717 }
2718
2719 static int get_object_list_from_bitmap(struct rev_info *revs)
2720 {
2721         if (prepare_bitmap_walk(revs) < 0)
2722                 return -1;
2723
2724         if (pack_options_allow_reuse() &&
2725             !reuse_partial_packfile_from_bitmap(
2726                         &reuse_packfile,
2727                         &reuse_packfile_objects,
2728                         &reuse_packfile_offset)) {
2729                 assert(reuse_packfile_objects);
2730                 nr_result += reuse_packfile_objects;
2731                 display_progress(progress_state, nr_result);
2732         }
2733
2734         traverse_bitmap_commit_list(&add_object_entry_from_bitmap);
2735         return 0;
2736 }
2737
2738 static void record_recent_object(struct object *obj,
2739                                  const char *name,
2740                                  void *data)
2741 {
2742         sha1_array_append(&recent_objects, obj->oid.hash);
2743 }
2744
2745 static void record_recent_commit(struct commit *commit, void *data)
2746 {
2747         sha1_array_append(&recent_objects, commit->object.oid.hash);
2748 }
2749
2750 static void get_object_list(int ac, const char **av)
2751 {
2752         struct rev_info revs;
2753         char line[1000];
2754         int flags = 0;
2755
2756         init_revisions(&revs, NULL);
2757         save_commit_buffer = 0;
2758         setup_revisions(ac, av, &revs, NULL);
2759
2760         /* make sure shallows are read */
2761         is_repository_shallow();
2762
2763         while (fgets(line, sizeof(line), stdin) != NULL) {
2764                 int len = strlen(line);
2765                 if (len && line[len - 1] == '\n')
2766                         line[--len] = 0;
2767                 if (!len)
2768                         break;
2769                 if (*line == '-') {
2770                         if (!strcmp(line, "--not")) {
2771                                 flags ^= UNINTERESTING;
2772                                 write_bitmap_index = 0;
2773                                 continue;
2774                         }
2775                         if (starts_with(line, "--shallow ")) {
2776                                 unsigned char sha1[20];
2777                                 if (get_sha1_hex(line + 10, sha1))
2778                                         die("not an SHA-1 '%s'", line + 10);
2779                                 register_shallow(sha1);
2780                                 use_bitmap_index = 0;
2781                                 continue;
2782                         }
2783                         die("not a rev '%s'", line);
2784                 }
2785                 if (handle_revision_arg(line, &revs, flags, REVARG_CANNOT_BE_FILENAME))
2786                         die("bad revision '%s'", line);
2787         }
2788
2789         if (use_bitmap_index && !get_object_list_from_bitmap(&revs))
2790                 return;
2791
2792         if (prepare_revision_walk(&revs))
2793                 die("revision walk setup failed");
2794         mark_edges_uninteresting(&revs, show_edge);
2795         traverse_commit_list(&revs, show_commit, show_object, NULL);
2796
2797         if (unpack_unreachable_expiration) {
2798                 revs.ignore_missing_links = 1;
2799                 if (add_unseen_recent_objects_to_traversal(&revs,
2800                                 unpack_unreachable_expiration))
2801                         die("unable to add recent objects");
2802                 if (prepare_revision_walk(&revs))
2803                         die("revision walk setup failed");
2804                 traverse_commit_list(&revs, record_recent_commit,
2805                                      record_recent_object, NULL);
2806         }
2807
2808         if (keep_unreachable)
2809                 add_objects_in_unpacked_packs(&revs);
2810         if (pack_loose_unreachable)
2811                 add_unreachable_loose_objects();
2812         if (unpack_unreachable)
2813                 loosen_unused_packed_objects(&revs);
2814
2815         sha1_array_clear(&recent_objects);
2816 }
2817
2818 static int option_parse_index_version(const struct option *opt,
2819                                       const char *arg, int unset)
2820 {
2821         char *c;
2822         const char *val = arg;
2823         pack_idx_opts.version = strtoul(val, &c, 10);
2824         if (pack_idx_opts.version > 2)
2825                 die(_("unsupported index version %s"), val);
2826         if (*c == ',' && c[1])
2827                 pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2828         if (*c || pack_idx_opts.off32_limit & 0x80000000)
2829                 die(_("bad index version '%s'"), val);
2830         return 0;
2831 }
2832
2833 static int option_parse_unpack_unreachable(const struct option *opt,
2834                                            const char *arg, int unset)
2835 {
2836         if (unset) {
2837                 unpack_unreachable = 0;
2838                 unpack_unreachable_expiration = 0;
2839         }
2840         else {
2841                 unpack_unreachable = 1;
2842                 if (arg)
2843                         unpack_unreachable_expiration = approxidate(arg);
2844         }
2845         return 0;
2846 }
2847
2848 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2849 {
2850         int use_internal_rev_list = 0;
2851         int thin = 0;
2852         int shallow = 0;
2853         int all_progress_implied = 0;
2854         struct argv_array rp = ARGV_ARRAY_INIT;
2855         int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
2856         int rev_list_index = 0;
2857         struct option pack_objects_options[] = {
2858                 OPT_SET_INT('q', "quiet", &progress,
2859                             N_("do not show progress meter"), 0),
2860                 OPT_SET_INT(0, "progress", &progress,
2861                             N_("show progress meter"), 1),
2862                 OPT_SET_INT(0, "all-progress", &progress,
2863                             N_("show progress meter during object writing phase"), 2),
2864                 OPT_BOOL(0, "all-progress-implied",
2865                          &all_progress_implied,
2866                          N_("similar to --all-progress when progress meter is shown")),
2867                 { OPTION_CALLBACK, 0, "index-version", NULL, N_("version[,offset]"),
2868                   N_("write the pack index file in the specified idx format version"),
2869                   0, option_parse_index_version },
2870                 OPT_MAGNITUDE(0, "max-pack-size", &pack_size_limit,
2871                               N_("maximum size of each output pack file")),
2872                 OPT_BOOL(0, "local", &local,
2873                          N_("ignore borrowed objects from alternate object store")),
2874                 OPT_BOOL(0, "incremental", &incremental,
2875                          N_("ignore packed objects")),
2876                 OPT_INTEGER(0, "window", &window,
2877                             N_("limit pack window by objects")),
2878                 OPT_MAGNITUDE(0, "window-memory", &window_memory_limit,
2879                               N_("limit pack window by memory in addition to object limit")),
2880                 OPT_INTEGER(0, "depth", &depth,
2881                             N_("maximum length of delta chain allowed in the resulting pack")),
2882                 OPT_BOOL(0, "reuse-delta", &reuse_delta,
2883                          N_("reuse existing deltas")),
2884                 OPT_BOOL(0, "reuse-object", &reuse_object,
2885                          N_("reuse existing objects")),
2886                 OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
2887                          N_("use OFS_DELTA objects")),
2888                 OPT_INTEGER(0, "threads", &delta_search_threads,
2889                             N_("use threads when searching for best delta matches")),
2890                 OPT_BOOL(0, "non-empty", &non_empty,
2891                          N_("do not create an empty pack output")),
2892                 OPT_BOOL(0, "revs", &use_internal_rev_list,
2893                          N_("read revision arguments from standard input")),
2894                 { OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
2895                   N_("limit the objects to those that are not yet packed"),
2896                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2897                 { OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
2898                   N_("include objects reachable from any reference"),
2899                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2900                 { OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
2901                   N_("include objects referred by reflog entries"),
2902                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2903                 { OPTION_SET_INT, 0, "indexed-objects", &rev_list_index, NULL,
2904                   N_("include objects referred to by the index"),
2905                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2906                 OPT_BOOL(0, "stdout", &pack_to_stdout,
2907                          N_("output pack to stdout")),
2908                 OPT_BOOL(0, "include-tag", &include_tag,
2909                          N_("include tag objects that refer to objects to be packed")),
2910                 OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
2911                          N_("keep unreachable objects")),
2912                 OPT_BOOL(0, "pack-loose-unreachable", &pack_loose_unreachable,
2913                          N_("pack loose unreachable objects")),
2914                 { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, N_("time"),
2915                   N_("unpack unreachable objects newer than <time>"),
2916                   PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
2917                 OPT_BOOL(0, "thin", &thin,
2918                          N_("create thin packs")),
2919                 OPT_BOOL(0, "shallow", &shallow,
2920                          N_("create packs suitable for shallow fetches")),
2921                 OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
2922                          N_("ignore packs that have companion .keep file")),
2923                 OPT_INTEGER(0, "compression", &pack_compression_level,
2924                             N_("pack compression level")),
2925                 OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
2926                             N_("do not hide commits by grafts"), 0),
2927                 OPT_BOOL(0, "use-bitmap-index", &use_bitmap_index,
2928                          N_("use a bitmap index if available to speed up counting objects")),
2929                 OPT_BOOL(0, "write-bitmap-index", &write_bitmap_index,
2930                          N_("write a bitmap index together with the pack index")),
2931                 OPT_END(),
2932         };
2933
2934         check_replace_refs = 0;
2935
2936         reset_pack_idx_option(&pack_idx_opts);
2937         git_config(git_pack_config, NULL);
2938
2939         progress = isatty(2);
2940         argc = parse_options(argc, argv, prefix, pack_objects_options,
2941                              pack_usage, 0);
2942
2943         if (argc) {
2944                 base_name = argv[0];
2945                 argc--;
2946         }
2947         if (pack_to_stdout != !base_name || argc)
2948                 usage_with_options(pack_usage, pack_objects_options);
2949
2950         argv_array_push(&rp, "pack-objects");
2951         if (thin) {
2952                 use_internal_rev_list = 1;
2953                 argv_array_push(&rp, shallow
2954                                 ? "--objects-edge-aggressive"
2955                                 : "--objects-edge");
2956         } else
2957                 argv_array_push(&rp, "--objects");
2958
2959         if (rev_list_all) {
2960                 use_internal_rev_list = 1;
2961                 argv_array_push(&rp, "--all");
2962         }
2963         if (rev_list_reflog) {
2964                 use_internal_rev_list = 1;
2965                 argv_array_push(&rp, "--reflog");
2966         }
2967         if (rev_list_index) {
2968                 use_internal_rev_list = 1;
2969                 argv_array_push(&rp, "--indexed-objects");
2970         }
2971         if (rev_list_unpacked) {
2972                 use_internal_rev_list = 1;
2973                 argv_array_push(&rp, "--unpacked");
2974         }
2975
2976         if (!reuse_object)
2977                 reuse_delta = 0;
2978         if (pack_compression_level == -1)
2979                 pack_compression_level = Z_DEFAULT_COMPRESSION;
2980         else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
2981                 die("bad pack compression level %d", pack_compression_level);
2982
2983         if (!delta_search_threads)      /* --threads=0 means autodetect */
2984                 delta_search_threads = online_cpus();
2985
2986 #ifdef NO_PTHREADS
2987         if (delta_search_threads != 1)
2988                 warning("no threads support, ignoring --threads");
2989 #endif
2990         if (!pack_to_stdout && !pack_size_limit)
2991                 pack_size_limit = pack_size_limit_cfg;
2992         if (pack_to_stdout && pack_size_limit)
2993                 die("--max-pack-size cannot be used to build a pack for transfer.");
2994         if (pack_size_limit && pack_size_limit < 1024*1024) {
2995                 warning("minimum pack size limit is 1 MiB");
2996                 pack_size_limit = 1024*1024;
2997         }
2998
2999         if (!pack_to_stdout && thin)
3000                 die("--thin cannot be used to build an indexable pack.");
3001
3002         if (keep_unreachable && unpack_unreachable)
3003                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
3004         if (!rev_list_all || !rev_list_reflog || !rev_list_index)
3005                 unpack_unreachable_expiration = 0;
3006
3007         /*
3008          * "soft" reasons not to use bitmaps - for on-disk repack by default we want
3009          *
3010          * - to produce good pack (with bitmap index not-yet-packed objects are
3011          *   packed in suboptimal order).
3012          *
3013          * - to use more robust pack-generation codepath (avoiding possible
3014          *   bugs in bitmap code and possible bitmap index corruption).
3015          */
3016         if (!pack_to_stdout)
3017                 use_bitmap_index_default = 0;
3018
3019         if (use_bitmap_index < 0)
3020                 use_bitmap_index = use_bitmap_index_default;
3021
3022         /* "hard" reasons not to use bitmaps; these just won't work at all */
3023         if (!use_internal_rev_list || (!pack_to_stdout && write_bitmap_index) || is_repository_shallow())
3024                 use_bitmap_index = 0;
3025
3026         if (pack_to_stdout || !rev_list_all)
3027                 write_bitmap_index = 0;
3028
3029         if (progress && all_progress_implied)
3030                 progress = 2;
3031
3032         prepare_packed_git();
3033         if (ignore_packed_keep) {
3034                 struct packed_git *p;
3035                 for (p = packed_git; p; p = p->next)
3036                         if (p->pack_local && p->pack_keep)
3037                                 break;
3038                 if (!p) /* no keep-able packs found */
3039                         ignore_packed_keep = 0;
3040         }
3041         if (local) {
3042                 /*
3043                  * unlike ignore_packed_keep above, we do not want to
3044                  * unset "local" based on looking at packs, as it
3045                  * also covers non-local objects
3046                  */
3047                 struct packed_git *p;
3048                 for (p = packed_git; p; p = p->next) {
3049                         if (!p->pack_local) {
3050                                 have_non_local_packs = 1;
3051                                 break;
3052                         }
3053                 }
3054         }
3055
3056         if (progress)
3057                 progress_state = start_progress(_("Counting objects"), 0);
3058         if (!use_internal_rev_list)
3059                 read_object_list_from_stdin();
3060         else {
3061                 get_object_list(rp.argc, rp.argv);
3062                 argv_array_clear(&rp);
3063         }
3064         cleanup_preferred_base();
3065         if (include_tag && nr_result)
3066                 for_each_ref(add_ref_tag, NULL);
3067         stop_progress(&progress_state);
3068
3069         if (non_empty && !nr_result)
3070                 return 0;
3071         if (nr_result)
3072                 prepare_pack(window, depth);
3073         write_pack_file();
3074         if (progress)
3075                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
3076                         " reused %"PRIu32" (delta %"PRIu32")\n",
3077                         written, written_delta, reused, reused_delta);
3078         return 0;
3079 }