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 "progress.h"
  18 #include "refs.h"
  19
  20 #ifdef THREADED_DELTA_SEARCH
  21 #include "thread-utils.h"
  22 #include <pthread.h>
  23 #endif
  24
  25 static const char pack_usage[] = "\
  26 git-pack-objects [{ -q | --progress | --all-progress }] \n\
  27         [--max-pack-size=N] [--local] [--incremental] \n\
  28         [--window=N] [--window-memory=N] [--depth=N] \n\
  29         [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
  30         [--threads=N] [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
  31         [--stdout | base-name] [--include-tag] [--keep-unreachable] \n\
  32         [<ref-list | <object-list]";
  33
  34 struct object_entry {
  35         struct pack_idx_entry idx;
  36         unsigned long size;     /* uncompressed size */
  37         struct packed_git *in_pack;     /* already in pack */
  38         off_t in_pack_offset;
  39         struct object_entry *delta;     /* delta base object */
  40         struct object_entry *delta_child; /* deltified objects who bases me */
  41         struct object_entry *delta_sibling; /* other deltified objects who
  42                                              * uses the same base as me
  43                                              */
  44         void *delta_data;       /* cached delta (uncompressed) */
  45         unsigned long delta_size;       /* delta data size (uncompressed) */
  46         unsigned int hash;      /* name hint hash */
  47         enum object_type type;
  48         enum object_type in_pack_type;  /* could be delta */
  49         unsigned char in_pack_header_size;
  50         unsigned char preferred_base; /* we do not pack this, but is available
  51                                        * to be used as the base object to delta
  52                                        * objects against.
  53                                        */
  54         unsigned char no_try_delta;
  55 };
  56
  57 /*
  58  * Objects we are going to pack are collected in objects array (dynamically
  59  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  60  * in the order we see -- typically rev-list --objects order that gives us
  61  * nice "minimum seek" order.
  62  */
  63 static struct object_entry *objects;
  64 static struct pack_idx_entry **written_list;
  65 static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  66
  67 static int non_empty;
  68 static int no_reuse_delta, no_reuse_object, keep_unreachable, include_tag;
  69 static int local;
  70 static int incremental;
  71 static int allow_ofs_delta;
  72 static const char *base_name;
  73 static int progress = 1;
  74 static int window = 10;
  75 static uint32_t pack_size_limit, pack_size_limit_cfg;
  76 static int depth = 50;
  77 static int delta_search_threads = 1;
  78 static int pack_to_stdout;
  79 static int num_preferred_base;
  80 static struct progress *progress_state;
  81 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  82 static int pack_compression_seen;
  83
  84 static unsigned long delta_cache_size = 0;
  85 static unsigned long max_delta_cache_size = 0;
  86 static unsigned long cache_max_small_delta_size = 1000;
  87
  88 static unsigned long window_memory_limit = 0;
  89
  90 /*
  91  * The object names in objects array are hashed with this hashtable,
  92  * to help looking up the entry by object name.
  93  * This hashtable is built after all the objects are seen.
  94  */
  95 static int *object_ix;
  96 static int object_ix_hashsz;
  97
  98 /*
  99  * stats
 100  */
 101 static uint32_t written, written_delta;
 102 static uint32_t reused, reused_delta;
 103
 104
 105 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 106 {
 107         unsigned long othersize, delta_size;
 108         enum object_type type;
 109         void *otherbuf = read_sha1_file(entry->delta->idx.sha1, &type, &othersize);
 110         void *delta_buf;
 111
 112         if (!otherbuf)
 113                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 114         delta_buf = diff_delta(otherbuf, othersize,
 115                                buf, size, &delta_size, 0);
 116         if (!delta_buf || delta_size != entry->delta_size)
 117                 die("delta size changed");
 118         free(buf);
 119         free(otherbuf);
 120         return delta_buf;
 121 }
 122
 123 /*
 124  * The per-object header is a pretty dense thing, which is
 125  *  - first byte: low four bits are "size", then three bits of "type",
 126  *    and the high bit is "size continues".
 127  *  - each byte afterwards: low seven bits are size continuation,
 128  *    with the high bit being "size continues"
 129  */
 130 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 131 {
 132         int n = 1;
 133         unsigned char c;
 134
 135         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 136                 die("bad type %d", type);
 137
 138         c = (type << 4) | (size & 15);
 139         size >>= 4;
 140         while (size) {
 141                 *hdr++ = c | 0x80;
 142                 c = size & 0x7f;
 143                 size >>= 7;
 144                 n++;
 145         }
 146         *hdr = c;
 147         return n;
 148 }
 149
 150 /*
 151  * we are going to reuse the existing object data as is.  make
 152  * sure it is not corrupt.
 153  */
 154 static int check_pack_inflate(struct packed_git *p,
 155                 struct pack_window **w_curs,
 156                 off_t offset,
 157                 off_t len,
 158                 unsigned long expect)
 159 {
 160         z_stream stream;
 161         unsigned char fakebuf[4096], *in;
 162         int st;
 163
 164         memset(&stream, 0, sizeof(stream));
 165         inflateInit(&stream);
 166         do {
 167                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 168                 stream.next_in = in;
 169                 stream.next_out = fakebuf;
 170                 stream.avail_out = sizeof(fakebuf);
 171                 st = inflate(&stream, Z_FINISH);
 172                 offset += stream.next_in - in;
 173         } while (st == Z_OK || st == Z_BUF_ERROR);
 174         inflateEnd(&stream);
 175         return (st == Z_STREAM_END &&
 176                 stream.total_out == expect &&
 177                 stream.total_in == len) ? 0 : -1;
 178 }
 179
 180 static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
 181                           off_t offset, off_t len, unsigned int nr)
 182 {
 183         const uint32_t *index_crc;
 184         uint32_t data_crc = crc32(0, Z_NULL, 0);
 185
 186         do {
 187                 unsigned int avail;
 188                 void *data = use_pack(p, w_curs, offset, &avail);
 189                 if (avail > len)
 190                         avail = len;
 191                 data_crc = crc32(data_crc, data, avail);
 192                 offset += avail;
 193                 len -= avail;
 194         } while (len);
 195
 196         index_crc = p->index_data;
 197         index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
 198
 199         return data_crc != ntohl(*index_crc);
 200 }
 201
 202 static void copy_pack_data(struct sha1file *f,
 203                 struct packed_git *p,
 204                 struct pack_window **w_curs,
 205                 off_t offset,
 206                 off_t len)
 207 {
 208         unsigned char *in;
 209         unsigned int avail;
 210
 211         while (len) {
 212                 in = use_pack(p, w_curs, offset, &avail);
 213                 if (avail > len)
 214                         avail = (unsigned int)len;
 215                 sha1write(f, in, avail);
 216                 offset += avail;
 217                 len -= avail;
 218         }
 219 }
 220
 221 static unsigned long write_object(struct sha1file *f,
 222                                   struct object_entry *entry,
 223                                   off_t write_offset)
 224 {
 225         unsigned long size;
 226         enum object_type type;
 227         void *buf;
 228         unsigned char header[10];
 229         unsigned char dheader[10];
 230         unsigned hdrlen;
 231         off_t datalen;
 232         enum object_type obj_type;
 233         int to_reuse = 0;
 234         /* write limit if limited packsize and not first object */
 235         unsigned long limit = pack_size_limit && nr_written ?
 236                                 pack_size_limit - write_offset : 0;
 237                                 /* no if no delta */
 238         int usable_delta =      !entry->delta ? 0 :
 239                                 /* yes if unlimited packfile */
 240                                 !pack_size_limit ? 1 :
 241                                 /* no if base written to previous pack */
 242                                 entry->delta->idx.offset == (off_t)-1 ? 0 :
 243                                 /* otherwise double-check written to this
 244                                  * pack,  like we do below
 245                                  */
 246                                 entry->delta->idx.offset ? 1 : 0;
 247
 248         if (!pack_to_stdout)
 249                 crc32_begin(f);
 250
 251         obj_type = entry->type;
 252         if (no_reuse_object)
 253                 to_reuse = 0;   /* explicit */
 254         else if (!entry->in_pack)
 255                 to_reuse = 0;   /* can't reuse what we don't have */
 256         else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 257                                 /* check_object() decided it for us ... */
 258                 to_reuse = usable_delta;
 259                                 /* ... but pack split may override that */
 260         else if (obj_type != entry->in_pack_type)
 261                 to_reuse = 0;   /* pack has delta which is unusable */
 262         else if (entry->delta)
 263                 to_reuse = 0;   /* we want to pack afresh */
 264         else
 265                 to_reuse = 1;   /* we have it in-pack undeltified,
 266                                  * and we do not need to deltify it.
 267                                  */
 268
 269         if (!to_reuse) {
 270                 z_stream stream;
 271                 unsigned long maxsize;
 272                 void *out;
 273                 if (!usable_delta) {
 274                         buf = read_sha1_file(entry->idx.sha1, &obj_type, &size);
 275                         if (!buf)
 276                                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 277                 } else if (entry->delta_data) {
 278                         size = entry->delta_size;
 279                         buf = entry->delta_data;
 280                         entry->delta_data = NULL;
 281                         obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 282                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 283                 } else {
 284                         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 285                         if (!buf)
 286                                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 287                         buf = delta_against(buf, size, entry);
 288                         size = entry->delta_size;
 289                         obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 290                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 291                 }
 292                 /* compress the data to store and put compressed length in datalen */
 293                 memset(&stream, 0, sizeof(stream));
 294                 deflateInit(&stream, pack_compression_level);
 295                 maxsize = deflateBound(&stream, size);
 296                 out = xmalloc(maxsize);
 297                 /* Compress it */
 298                 stream.next_in = buf;
 299                 stream.avail_in = size;
 300                 stream.next_out = out;
 301                 stream.avail_out = maxsize;
 302                 while (deflate(&stream, Z_FINISH) == Z_OK)
 303                         /* nothing */;
 304                 deflateEnd(&stream);
 305                 datalen = stream.total_out;
 306
 307                 /*
 308                  * The object header is a byte of 'type' followed by zero or
 309                  * more bytes of length.
 310                  */
 311                 hdrlen = encode_header(obj_type, size, header);
 312
 313                 if (obj_type == OBJ_OFS_DELTA) {
 314                         /*
 315                          * Deltas with relative base contain an additional
 316                          * encoding of the relative offset for the delta
 317                          * base from this object's position in the pack.
 318                          */
 319                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 320                         unsigned pos = sizeof(dheader) - 1;
 321                         dheader[pos] = ofs & 127;
 322                         while (ofs >>= 7)
 323                                 dheader[--pos] = 128 | (--ofs & 127);
 324                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 325                                 free(out);
 326                                 free(buf);
 327                                 return 0;
 328                         }
 329                         sha1write(f, header, hdrlen);
 330                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 331                         hdrlen += sizeof(dheader) - pos;
 332                 } else if (obj_type == OBJ_REF_DELTA) {
 333                         /*
 334                          * Deltas with a base reference contain
 335                          * an additional 20 bytes for the base sha1.
 336                          */
 337                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 338                                 free(out);
 339                                 free(buf);
 340                                 return 0;
 341                         }
 342                         sha1write(f, header, hdrlen);
 343                         sha1write(f, entry->delta->idx.sha1, 20);
 344                         hdrlen += 20;
 345                 } else {
 346                         if (limit && hdrlen + datalen + 20 >= limit) {
 347                                 free(out);
 348                                 free(buf);
 349                                 return 0;
 350                         }
 351                         sha1write(f, header, hdrlen);
 352                 }
 353                 sha1write(f, out, datalen);
 354                 free(out);
 355                 free(buf);
 356         }
 357         else {
 358                 struct packed_git *p = entry->in_pack;
 359                 struct pack_window *w_curs = NULL;
 360                 struct revindex_entry *revidx;
 361                 off_t offset;
 362
 363                 if (entry->delta) {
 364                         obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 365                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 366                         reused_delta++;
 367                 }
 368                 hdrlen = encode_header(obj_type, entry->size, header);
 369                 offset = entry->in_pack_offset;
 370                 revidx = find_pack_revindex(p, offset);
 371                 datalen = revidx[1].offset - offset;
 372                 if (!pack_to_stdout && p->index_version > 1 &&
 373                     check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
 374                         die("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 375                 offset += entry->in_pack_header_size;
 376                 datalen -= entry->in_pack_header_size;
 377                 if (obj_type == OBJ_OFS_DELTA) {
 378                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 379                         unsigned pos = sizeof(dheader) - 1;
 380                         dheader[pos] = ofs & 127;
 381                         while (ofs >>= 7)
 382                                 dheader[--pos] = 128 | (--ofs & 127);
 383                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit)
 384                                 return 0;
 385                         sha1write(f, header, hdrlen);
 386                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 387                         hdrlen += sizeof(dheader) - pos;
 388                 } else if (obj_type == OBJ_REF_DELTA) {
 389                         if (limit && hdrlen + 20 + datalen + 20 >= limit)
 390                                 return 0;
 391                         sha1write(f, header, hdrlen);
 392                         sha1write(f, entry->delta->idx.sha1, 20);
 393                         hdrlen += 20;
 394                 } else {
 395                         if (limit && hdrlen + datalen + 20 >= limit)
 396                                 return 0;
 397                         sha1write(f, header, hdrlen);
 398                 }
 399
 400                 if (!pack_to_stdout && p->index_version == 1 &&
 401                     check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
 402                         die("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 403                 copy_pack_data(f, p, &w_curs, offset, datalen);
 404                 unuse_pack(&w_curs);
 405                 reused++;
 406         }
 407         if (usable_delta)
 408                 written_delta++;
 409         written++;
 410         if (!pack_to_stdout)
 411                 entry->idx.crc32 = crc32_end(f);
 412         return hdrlen + datalen;
 413 }
 414
 415 static off_t write_one(struct sha1file *f,
 416                                struct object_entry *e,
 417                                off_t offset)
 418 {
 419         unsigned long size;
 420
 421         /* offset is non zero if object is written already. */
 422         if (e->idx.offset || e->preferred_base)
 423                 return offset;
 424
 425         /* if we are deltified, write out base object first. */
 426         if (e->delta) {
 427                 offset = write_one(f, e->delta, offset);
 428                 if (!offset)
 429                         return 0;
 430         }
 431
 432         e->idx.offset = offset;
 433         size = write_object(f, e, offset);
 434         if (!size) {
 435                 e->idx.offset = 0;
 436                 return 0;
 437         }
 438         written_list[nr_written++] = &e->idx;
 439
 440         /* make sure off_t is sufficiently large not to wrap */
 441         if (offset > offset + size)
 442                 die("pack too large for current definition of off_t");
 443         return offset + size;
 444 }
 445
 446 /* forward declaration for write_pack_file */
 447 static int adjust_perm(const char *path, mode_t mode);
 448
 449 static void write_pack_file(void)
 450 {
 451         uint32_t i = 0, j;
 452         struct sha1file *f;
 453         off_t offset, offset_one, last_obj_offset = 0;
 454         struct pack_header hdr;
 455         int do_progress = progress >> pack_to_stdout;
 456         uint32_t nr_remaining = nr_result;
 457         time_t last_mtime = 0;
 458
 459         if (do_progress)
 460                 progress_state = start_progress("Writing objects", nr_result);
 461         written_list = xmalloc(nr_objects * sizeof(*written_list));
 462
 463         do {
 464                 unsigned char sha1[20];
 465                 char *pack_tmp_name = NULL;
 466
 467                 if (pack_to_stdout) {
 468                         f = sha1fd_throughput(1, "<stdout>", progress_state);
 469                 } else {
 470                         char tmpname[PATH_MAX];
 471                         int fd;
 472                         snprintf(tmpname, sizeof(tmpname),
 473                                  "%s/tmp_pack_XXXXXX", get_object_directory());
 474                         fd = xmkstemp(tmpname);
 475                         pack_tmp_name = xstrdup(tmpname);
 476                         f = sha1fd(fd, pack_tmp_name);
 477                 }
 478
 479                 hdr.hdr_signature = htonl(PACK_SIGNATURE);
 480                 hdr.hdr_version = htonl(PACK_VERSION);
 481                 hdr.hdr_entries = htonl(nr_remaining);
 482                 sha1write(f, &hdr, sizeof(hdr));
 483                 offset = sizeof(hdr);
 484                 nr_written = 0;
 485                 for (; i < nr_objects; i++) {
 486                         last_obj_offset = offset;
 487                         offset_one = write_one(f, objects + i, offset);
 488                         if (!offset_one)
 489                                 break;
 490                         offset = offset_one;
 491                         display_progress(progress_state, written);
 492                 }
 493
 494                 /*
 495                  * Did we write the wrong # entries in the header?
 496                  * If so, rewrite it like in fast-import
 497                  */
 498                 if (pack_to_stdout || nr_written == nr_remaining) {
 499                         sha1close(f, sha1, 1);
 500                 } else {
 501                         int fd = sha1close(f, NULL, 0);
 502                         fixup_pack_header_footer(fd, sha1, pack_tmp_name, nr_written);
 503                         close(fd);
 504                 }
 505
 506                 if (!pack_to_stdout) {
 507                         mode_t mode = umask(0);
 508                         struct stat st;
 509                         char *idx_tmp_name, tmpname[PATH_MAX];
 510
 511                         umask(mode);
 512                         mode = 0444 & ~mode;
 513
 514                         idx_tmp_name = write_idx_file(NULL, written_list,
 515                                                       nr_written, sha1);
 516
 517                         snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
 518                                  base_name, sha1_to_hex(sha1));
 519                         if (adjust_perm(pack_tmp_name, mode))
 520                                 die("unable to make temporary pack file readable: %s",
 521                                     strerror(errno));
 522                         if (rename(pack_tmp_name, tmpname))
 523                                 die("unable to rename temporary pack file: %s",
 524                                     strerror(errno));
 525
 526                         /*
 527                          * Packs are runtime accessed in their mtime
 528                          * order since newer packs are more likely to contain
 529                          * younger objects.  So if we are creating multiple
 530                          * packs then we should modify the mtime of later ones
 531                          * to preserve this property.
 532                          */
 533                         if (stat(tmpname, &st) < 0) {
 534                                 warning("failed to stat %s: %s",
 535                                         tmpname, strerror(errno));
 536                         } else if (!last_mtime) {
 537                                 last_mtime = st.st_mtime;
 538                         } else {
 539                                 struct utimbuf utb;
 540                                 utb.actime = st.st_atime;
 541                                 utb.modtime = --last_mtime;
 542                                 if (utime(tmpname, &utb) < 0)
 543                                         warning("failed utime() on %s: %s",
 544                                                 tmpname, strerror(errno));
 545                         }
 546
 547                         snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
 548                                  base_name, sha1_to_hex(sha1));
 549                         if (adjust_perm(idx_tmp_name, mode))
 550                                 die("unable to make temporary index file readable: %s",
 551                                     strerror(errno));
 552                         if (rename(idx_tmp_name, tmpname))
 553                                 die("unable to rename temporary index file: %s",
 554                                     strerror(errno));
 555
 556                         free(idx_tmp_name);
 557                         free(pack_tmp_name);
 558                         puts(sha1_to_hex(sha1));
 559                 }
 560
 561                 /* mark written objects as written to previous pack */
 562                 for (j = 0; j < nr_written; j++) {
 563                         written_list[j]->offset = (off_t)-1;
 564                 }
 565                 nr_remaining -= nr_written;
 566         } while (nr_remaining && i < nr_objects);
 567
 568         free(written_list);
 569         stop_progress(&progress_state);
 570         if (written != nr_result)
 571                 die("wrote %u objects while expecting %u", written, nr_result);
 572         /*
 573          * We have scanned through [0 ... i).  Since we have written
 574          * the correct number of objects,  the remaining [i ... nr_objects)
 575          * items must be either already written (due to out-of-order delta base)
 576          * or a preferred base.  Count those which are neither and complain if any.
 577          */
 578         for (j = 0; i < nr_objects; i++) {
 579                 struct object_entry *e = objects + i;
 580                 j += !e->idx.offset && !e->preferred_base;
 581         }
 582         if (j)
 583                 die("wrote %u objects as expected but %u unwritten", written, j);
 584 }
 585
 586 static int locate_object_entry_hash(const unsigned char *sha1)
 587 {
 588         int i;
 589         unsigned int ui;
 590         memcpy(&ui, sha1, sizeof(unsigned int));
 591         i = ui % object_ix_hashsz;
 592         while (0 < object_ix[i]) {
 593                 if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 594                         return i;
 595                 if (++i == object_ix_hashsz)
 596                         i = 0;
 597         }
 598         return -1 - i;
 599 }
 600
 601 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 602 {
 603         int i;
 604
 605         if (!object_ix_hashsz)
 606                 return NULL;
 607
 608         i = locate_object_entry_hash(sha1);
 609         if (0 <= i)
 610                 return &objects[object_ix[i]-1];
 611         return NULL;
 612 }
 613
 614 static void rehash_objects(void)
 615 {
 616         uint32_t i;
 617         struct object_entry *oe;
 618
 619         object_ix_hashsz = nr_objects * 3;
 620         if (object_ix_hashsz < 1024)
 621                 object_ix_hashsz = 1024;
 622         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 623         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 624         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 625                 int ix = locate_object_entry_hash(oe->idx.sha1);
 626                 if (0 <= ix)
 627                         continue;
 628                 ix = -1 - ix;
 629                 object_ix[ix] = i + 1;
 630         }
 631 }
 632
 633 static unsigned name_hash(const char *name)
 634 {
 635         unsigned char c;
 636         unsigned hash = 0;
 637
 638         if (!name)
 639                 return 0;
 640
 641         /*
 642          * This effectively just creates a sortable number from the
 643          * last sixteen non-whitespace characters. Last characters
 644          * count "most", so things that end in ".c" sort together.
 645          */
 646         while ((c = *name++) != 0) {
 647                 if (isspace(c))
 648                         continue;
 649                 hash = (hash >> 2) + (c << 24);
 650         }
 651         return hash;
 652 }
 653
 654 static void setup_delta_attr_check(struct git_attr_check *check)
 655 {
 656         static struct git_attr *attr_delta;
 657
 658         if (!attr_delta)
 659                 attr_delta = git_attr("delta", 5);
 660
 661         check[0].attr = attr_delta;
 662 }
 663
 664 static int no_try_delta(const char *path)
 665 {
 666         struct git_attr_check check[1];
 667
 668         setup_delta_attr_check(check);
 669         if (git_checkattr(path, ARRAY_SIZE(check), check))
 670                 return 0;
 671         if (ATTR_FALSE(check->value))
 672                 return 1;
 673         return 0;
 674 }
 675
 676 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 677                             const char *name, int exclude)
 678 {
 679         struct object_entry *entry;
 680         struct packed_git *p, *found_pack = NULL;
 681         off_t found_offset = 0;
 682         int ix;
 683         unsigned hash = name_hash(name);
 684
 685         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 686         if (ix >= 0) {
 687                 if (exclude) {
 688                         entry = objects + object_ix[ix] - 1;
 689                         if (!entry->preferred_base)
 690                                 nr_result--;
 691                         entry->preferred_base = 1;
 692                 }
 693                 return 0;
 694         }
 695
 696         for (p = packed_git; p; p = p->next) {
 697                 off_t offset = find_pack_entry_one(sha1, p);
 698                 if (offset) {
 699                         if (!found_pack) {
 700                                 found_offset = offset;
 701                                 found_pack = p;
 702                         }
 703                         if (exclude)
 704                                 break;
 705                         if (incremental)
 706                                 return 0;
 707                         if (local && !p->pack_local)
 708                                 return 0;
 709                 }
 710         }
 711
 712         if (nr_objects >= nr_alloc) {
 713                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 714                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 715         }
 716
 717         entry = objects + nr_objects++;
 718         memset(entry, 0, sizeof(*entry));
 719         hashcpy(entry->idx.sha1, sha1);
 720         entry->hash = hash;
 721         if (type)
 722                 entry->type = type;
 723         if (exclude)
 724                 entry->preferred_base = 1;
 725         else
 726                 nr_result++;
 727         if (found_pack) {
 728                 entry->in_pack = found_pack;
 729                 entry->in_pack_offset = found_offset;
 730         }
 731
 732         if (object_ix_hashsz * 3 <= nr_objects * 4)
 733                 rehash_objects();
 734         else
 735                 object_ix[-1 - ix] = nr_objects;
 736
 737         display_progress(progress_state, nr_objects);
 738
 739         if (name && no_try_delta(name))
 740                 entry->no_try_delta = 1;
 741
 742         return 1;
 743 }
 744
 745 struct pbase_tree_cache {
 746         unsigned char sha1[20];
 747         int ref;
 748         int temporary;
 749         void *tree_data;
 750         unsigned long tree_size;
 751 };
 752
 753 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 754 static int pbase_tree_cache_ix(const unsigned char *sha1)
 755 {
 756         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 757 }
 758 static int pbase_tree_cache_ix_incr(int ix)
 759 {
 760         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 761 }
 762
 763 static struct pbase_tree {
 764         struct pbase_tree *next;
 765         /* This is a phony "cache" entry; we are not
 766          * going to evict it nor find it through _get()
 767          * mechanism -- this is for the toplevel node that
 768          * would almost always change with any commit.
 769          */
 770         struct pbase_tree_cache pcache;
 771 } *pbase_tree;
 772
 773 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 774 {
 775         struct pbase_tree_cache *ent, *nent;
 776         void *data;
 777         unsigned long size;
 778         enum object_type type;
 779         int neigh;
 780         int my_ix = pbase_tree_cache_ix(sha1);
 781         int available_ix = -1;
 782
 783         /* pbase-tree-cache acts as a limited hashtable.
 784          * your object will be found at your index or within a few
 785          * slots after that slot if it is cached.
 786          */
 787         for (neigh = 0; neigh < 8; neigh++) {
 788                 ent = pbase_tree_cache[my_ix];
 789                 if (ent && !hashcmp(ent->sha1, sha1)) {
 790                         ent->ref++;
 791                         return ent;
 792                 }
 793                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 794                          ((0 <= available_ix) &&
 795                           (!ent && pbase_tree_cache[available_ix])))
 796                         available_ix = my_ix;
 797                 if (!ent)
 798                         break;
 799                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 800         }
 801
 802         /* Did not find one.  Either we got a bogus request or
 803          * we need to read and perhaps cache.
 804          */
 805         data = read_sha1_file(sha1, &type, &size);
 806         if (!data)
 807                 return NULL;
 808         if (type != OBJ_TREE) {
 809                 free(data);
 810                 return NULL;
 811         }
 812
 813         /* We need to either cache or return a throwaway copy */
 814
 815         if (available_ix < 0)
 816                 ent = NULL;
 817         else {
 818                 ent = pbase_tree_cache[available_ix];
 819                 my_ix = available_ix;
 820         }
 821
 822         if (!ent) {
 823                 nent = xmalloc(sizeof(*nent));
 824                 nent->temporary = (available_ix < 0);
 825         }
 826         else {
 827                 /* evict and reuse */
 828                 free(ent->tree_data);
 829                 nent = ent;
 830         }
 831         hashcpy(nent->sha1, sha1);
 832         nent->tree_data = data;
 833         nent->tree_size = size;
 834         nent->ref = 1;
 835         if (!nent->temporary)
 836                 pbase_tree_cache[my_ix] = nent;
 837         return nent;
 838 }
 839
 840 static void pbase_tree_put(struct pbase_tree_cache *cache)
 841 {
 842         if (!cache->temporary) {
 843                 cache->ref--;
 844                 return;
 845         }
 846         free(cache->tree_data);
 847         free(cache);
 848 }
 849
 850 static int name_cmp_len(const char *name)
 851 {
 852         int i;
 853         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 854                 ;
 855         return i;
 856 }
 857
 858 static void add_pbase_object(struct tree_desc *tree,
 859                              const char *name,
 860                              int cmplen,
 861                              const char *fullname)
 862 {
 863         struct name_entry entry;
 864         int cmp;
 865
 866         while (tree_entry(tree,&entry)) {
 867                 if (S_ISGITLINK(entry.mode))
 868                         continue;
 869                 cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
 870                       memcmp(name, entry.path, cmplen);
 871                 if (cmp > 0)
 872                         continue;
 873                 if (cmp < 0)
 874                         return;
 875                 if (name[cmplen] != '/') {
 876                         add_object_entry(entry.sha1,
 877                                          object_type(entry.mode),
 878                                          fullname, 1);
 879                         return;
 880                 }
 881                 if (S_ISDIR(entry.mode)) {
 882                         struct tree_desc sub;
 883                         struct pbase_tree_cache *tree;
 884                         const char *down = name+cmplen+1;
 885                         int downlen = name_cmp_len(down);
 886
 887                         tree = pbase_tree_get(entry.sha1);
 888                         if (!tree)
 889                                 return;
 890                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
 891
 892                         add_pbase_object(&sub, down, downlen, fullname);
 893                         pbase_tree_put(tree);
 894                 }
 895         }
 896 }
 897
 898 static unsigned *done_pbase_paths;
 899 static int done_pbase_paths_num;
 900 static int done_pbase_paths_alloc;
 901 static int done_pbase_path_pos(unsigned hash)
 902 {
 903         int lo = 0;
 904         int hi = done_pbase_paths_num;
 905         while (lo < hi) {
 906                 int mi = (hi + lo) / 2;
 907                 if (done_pbase_paths[mi] == hash)
 908                         return mi;
 909                 if (done_pbase_paths[mi] < hash)
 910                         hi = mi;
 911                 else
 912                         lo = mi + 1;
 913         }
 914         return -lo-1;
 915 }
 916
 917 static int check_pbase_path(unsigned hash)
 918 {
 919         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 920         if (0 <= pos)
 921                 return 1;
 922         pos = -pos - 1;
 923         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 924                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 925                 done_pbase_paths = xrealloc(done_pbase_paths,
 926                                             done_pbase_paths_alloc *
 927                                             sizeof(unsigned));
 928         }
 929         done_pbase_paths_num++;
 930         if (pos < done_pbase_paths_num)
 931                 memmove(done_pbase_paths + pos + 1,
 932                         done_pbase_paths + pos,
 933                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 934         done_pbase_paths[pos] = hash;
 935         return 0;
 936 }
 937
 938 static void add_preferred_base_object(const char *name)
 939 {
 940         struct pbase_tree *it;
 941         int cmplen;
 942         unsigned hash = name_hash(name);
 943
 944         if (!num_preferred_base || check_pbase_path(hash))
 945                 return;
 946
 947         cmplen = name_cmp_len(name);
 948         for (it = pbase_tree; it; it = it->next) {
 949                 if (cmplen == 0) {
 950                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
 951                 }
 952                 else {
 953                         struct tree_desc tree;
 954                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
 955                         add_pbase_object(&tree, name, cmplen, name);
 956                 }
 957         }
 958 }
 959
 960 static void add_preferred_base(unsigned char *sha1)
 961 {
 962         struct pbase_tree *it;
 963         void *data;
 964         unsigned long size;
 965         unsigned char tree_sha1[20];
 966
 967         if (window <= num_preferred_base++)
 968                 return;
 969
 970         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 971         if (!data)
 972                 return;
 973
 974         for (it = pbase_tree; it; it = it->next) {
 975                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
 976                         free(data);
 977                         return;
 978                 }
 979         }
 980
 981         it = xcalloc(1, sizeof(*it));
 982         it->next = pbase_tree;
 983         pbase_tree = it;
 984
 985         hashcpy(it->pcache.sha1, tree_sha1);
 986         it->pcache.tree_data = data;
 987         it->pcache.tree_size = size;
 988 }
 989
 990 static void check_object(struct object_entry *entry)
 991 {
 992         if (entry->in_pack) {
 993                 struct packed_git *p = entry->in_pack;
 994                 struct pack_window *w_curs = NULL;
 995                 const unsigned char *base_ref = NULL;
 996                 struct object_entry *base_entry;
 997                 unsigned long used, used_0;
 998                 unsigned int avail;
 999                 off_t ofs;
1000                 unsigned char *buf, c;
1001
1002                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1003
1004                 /*
1005                  * We want in_pack_type even if we do not reuse delta
1006                  * since non-delta representations could still be reused.
1007                  */
1008                 used = unpack_object_header_gently(buf, avail,
1009                                                    &entry->in_pack_type,
1010                                                    &entry->size);
1011
1012                 /*
1013                  * Determine if this is a delta and if so whether we can
1014                  * reuse it or not.  Otherwise let's find out as cheaply as
1015                  * possible what the actual type and size for this object is.
1016                  */
1017                 switch (entry->in_pack_type) {
1018                 default:
1019                         /* Not a delta hence we've already got all we need. */
1020                         entry->type = entry->in_pack_type;
1021                         entry->in_pack_header_size = used;
1022                         unuse_pack(&w_curs);
1023                         return;
1024                 case OBJ_REF_DELTA:
1025                         if (!no_reuse_delta && !entry->preferred_base)
1026                                 base_ref = use_pack(p, &w_curs,
1027                                                 entry->in_pack_offset + used, NULL);
1028                         entry->in_pack_header_size = used + 20;
1029                         break;
1030                 case OBJ_OFS_DELTA:
1031                         buf = use_pack(p, &w_curs,
1032                                        entry->in_pack_offset + used, NULL);
1033                         used_0 = 0;
1034                         c = buf[used_0++];
1035                         ofs = c & 127;
1036                         while (c & 128) {
1037                                 ofs += 1;
1038                                 if (!ofs || MSB(ofs, 7))
1039                                         die("delta base offset overflow in pack for %s",
1040                                             sha1_to_hex(entry->idx.sha1));
1041                                 c = buf[used_0++];
1042                                 ofs = (ofs << 7) + (c & 127);
1043                         }
1044                         if (ofs >= entry->in_pack_offset)
1045                                 die("delta base offset out of bound for %s",
1046                                     sha1_to_hex(entry->idx.sha1));
1047                         ofs = entry->in_pack_offset - ofs;
1048                         if (!no_reuse_delta && !entry->preferred_base) {
1049                                 struct revindex_entry *revidx;
1050                                 revidx = find_pack_revindex(p, ofs);
1051                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1052                         }
1053                         entry->in_pack_header_size = used + used_0;
1054                         break;
1055                 }
1056
1057                 if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1058                         /*
1059                          * If base_ref was set above that means we wish to
1060                          * reuse delta data, and we even found that base
1061                          * in the list of objects we want to pack. Goodie!
1062                          *
1063                          * Depth value does not matter - find_deltas() will
1064                          * never consider reused delta as the base object to
1065                          * deltify other objects against, in order to avoid
1066                          * circular deltas.
1067                          */
1068                         entry->type = entry->in_pack_type;
1069                         entry->delta = base_entry;
1070                         entry->delta_sibling = base_entry->delta_child;
1071                         base_entry->delta_child = entry;
1072                         unuse_pack(&w_curs);
1073                         return;
1074                 }
1075
1076                 if (entry->type) {
1077                         /*
1078                          * This must be a delta and we already know what the
1079                          * final object type is.  Let's extract the actual
1080                          * object size from the delta header.
1081                          */
1082                         entry->size = get_size_from_delta(p, &w_curs,
1083                                         entry->in_pack_offset + entry->in_pack_header_size);
1084                         unuse_pack(&w_curs);
1085                         return;
1086                 }
1087
1088                 /*
1089                  * No choice but to fall back to the recursive delta walk
1090                  * with sha1_object_info() to find about the object type
1091                  * at this point...
1092                  */
1093                 unuse_pack(&w_curs);
1094         }
1095
1096         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1097         if (entry->type < 0)
1098                 die("unable to get type of object %s",
1099                     sha1_to_hex(entry->idx.sha1));
1100 }
1101
1102 static int pack_offset_sort(const void *_a, const void *_b)
1103 {
1104         const struct object_entry *a = *(struct object_entry **)_a;
1105         const struct object_entry *b = *(struct object_entry **)_b;
1106
1107         /* avoid filesystem trashing with loose objects */
1108         if (!a->in_pack && !b->in_pack)
1109                 return hashcmp(a->idx.sha1, b->idx.sha1);
1110
1111         if (a->in_pack < b->in_pack)
1112                 return -1;
1113         if (a->in_pack > b->in_pack)
1114                 return 1;
1115         return a->in_pack_offset < b->in_pack_offset ? -1 :
1116                         (a->in_pack_offset > b->in_pack_offset);
1117 }
1118
1119 static void get_object_details(void)
1120 {
1121         uint32_t i;
1122         struct object_entry **sorted_by_offset;
1123
1124         sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1125         for (i = 0; i < nr_objects; i++)
1126                 sorted_by_offset[i] = objects + i;
1127         qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1128
1129         init_pack_revindex();
1130
1131         for (i = 0; i < nr_objects; i++)
1132                 check_object(sorted_by_offset[i]);
1133
1134         free(sorted_by_offset);
1135 }
1136
1137 /*
1138  * We search for deltas in a list sorted by type, by filename hash, and then
1139  * by size, so that we see progressively smaller and smaller files.
1140  * That's because we prefer deltas to be from the bigger file
1141  * to the smaller -- deletes are potentially cheaper, but perhaps
1142  * more importantly, the bigger file is likely the more recent
1143  * one.  The deepest deltas are therefore the oldest objects which are
1144  * less susceptible to be accessed often.
1145  */
1146 static int type_size_sort(const void *_a, const void *_b)
1147 {
1148         const struct object_entry *a = *(struct object_entry **)_a;
1149         const struct object_entry *b = *(struct object_entry **)_b;
1150
1151         if (a->type > b->type)
1152                 return -1;
1153         if (a->type < b->type)
1154                 return 1;
1155         if (a->hash > b->hash)
1156                 return -1;
1157         if (a->hash < b->hash)
1158                 return 1;
1159         if (a->preferred_base > b->preferred_base)
1160                 return -1;
1161         if (a->preferred_base < b->preferred_base)
1162                 return 1;
1163         if (a->size > b->size)
1164                 return -1;
1165         if (a->size < b->size)
1166                 return 1;
1167         return a < b ? -1 : (a > b);  /* newest first */
1168 }
1169
1170 struct unpacked {
1171         struct object_entry *entry;
1172         void *data;
1173         struct delta_index *index;
1174         unsigned depth;
1175 };
1176
1177 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1178                            unsigned long delta_size)
1179 {
1180         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1181                 return 0;
1182
1183         if (delta_size < cache_max_small_delta_size)
1184                 return 1;
1185
1186         /* cache delta, if objects are large enough compared to delta size */
1187         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1188                 return 1;
1189
1190         return 0;
1191 }
1192
1193 #ifdef THREADED_DELTA_SEARCH
1194
1195 static pthread_mutex_t read_mutex = PTHREAD_MUTEX_INITIALIZER;
1196 #define read_lock()             pthread_mutex_lock(&read_mutex)
1197 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1198
1199 static pthread_mutex_t cache_mutex = PTHREAD_MUTEX_INITIALIZER;
1200 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1201 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1202
1203 static pthread_mutex_t progress_mutex = PTHREAD_MUTEX_INITIALIZER;
1204 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1205 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1206
1207 #else
1208
1209 #define read_lock()             (void)0
1210 #define read_unlock()           (void)0
1211 #define cache_lock()            (void)0
1212 #define cache_unlock()          (void)0
1213 #define progress_lock()         (void)0
1214 #define progress_unlock()       (void)0
1215
1216 #endif
1217
1218 static int try_delta(struct unpacked *trg, struct unpacked *src,
1219                      unsigned max_depth, unsigned long *mem_usage)
1220 {
1221         struct object_entry *trg_entry = trg->entry;
1222         struct object_entry *src_entry = src->entry;
1223         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1224         unsigned ref_depth;
1225         enum object_type type;
1226         void *delta_buf;
1227
1228         /* Don't bother doing diffs between different types */
1229         if (trg_entry->type != src_entry->type)
1230                 return -1;
1231
1232         /*
1233          * We do not bother to try a delta that we discarded
1234          * on an earlier try, but only when reusing delta data.
1235          */
1236         if (!no_reuse_delta && trg_entry->in_pack &&
1237             trg_entry->in_pack == src_entry->in_pack &&
1238             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1239             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1240                 return 0;
1241
1242         /* Let's not bust the allowed depth. */
1243         if (src->depth >= max_depth)
1244                 return 0;
1245
1246         /* Now some size filtering heuristics. */
1247         trg_size = trg_entry->size;
1248         if (!trg_entry->delta) {
1249                 max_size = trg_size/2 - 20;
1250                 ref_depth = 1;
1251         } else {
1252                 max_size = trg_entry->delta_size;
1253                 ref_depth = trg->depth;
1254         }
1255         max_size = max_size * (max_depth - src->depth) /
1256                                                 (max_depth - ref_depth + 1);
1257         if (max_size == 0)
1258                 return 0;
1259         src_size = src_entry->size;
1260         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1261         if (sizediff >= max_size)
1262                 return 0;
1263         if (trg_size < src_size / 32)
1264                 return 0;
1265
1266         /* Load data if not already done */
1267         if (!trg->data) {
1268                 read_lock();
1269                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1270                 read_unlock();
1271                 if (!trg->data)
1272                         die("object %s cannot be read",
1273                             sha1_to_hex(trg_entry->idx.sha1));
1274                 if (sz != trg_size)
1275                         die("object %s inconsistent object length (%lu vs %lu)",
1276                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1277                 *mem_usage += sz;
1278         }
1279         if (!src->data) {
1280                 read_lock();
1281                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1282                 read_unlock();
1283                 if (!src->data)
1284                         die("object %s cannot be read",
1285                             sha1_to_hex(src_entry->idx.sha1));
1286                 if (sz != src_size)
1287                         die("object %s inconsistent object length (%lu vs %lu)",
1288                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1289                 *mem_usage += sz;
1290         }
1291         if (!src->index) {
1292                 src->index = create_delta_index(src->data, src_size);
1293                 if (!src->index) {
1294                         static int warned = 0;
1295                         if (!warned++)
1296                                 warning("suboptimal pack - out of memory");
1297                         return 0;
1298                 }
1299                 *mem_usage += sizeof_delta_index(src->index);
1300         }
1301
1302         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1303         if (!delta_buf)
1304                 return 0;
1305
1306         if (trg_entry->delta) {
1307                 /* Prefer only shallower same-sized deltas. */
1308                 if (delta_size == trg_entry->delta_size &&
1309                     src->depth + 1 >= trg->depth) {
1310                         free(delta_buf);
1311                         return 0;
1312                 }
1313         }
1314
1315         /*
1316          * Handle memory allocation outside of the cache
1317          * accounting lock.  Compiler will optimize the strangeness
1318          * away when THREADED_DELTA_SEARCH is not defined.
1319          */
1320         free(trg_entry->delta_data);
1321         cache_lock();
1322         if (trg_entry->delta_data) {
1323                 delta_cache_size -= trg_entry->delta_size;
1324                 trg_entry->delta_data = NULL;
1325         }
1326         if (delta_cacheable(src_size, trg_size, delta_size)) {
1327                 delta_cache_size += delta_size;
1328                 cache_unlock();
1329                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1330         } else {
1331                 cache_unlock();
1332                 free(delta_buf);
1333         }
1334
1335         trg_entry->delta = src_entry;
1336         trg_entry->delta_size = delta_size;
1337         trg->depth = src->depth + 1;
1338
1339         return 1;
1340 }
1341
1342 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1343 {
1344         struct object_entry *child = me->delta_child;
1345         unsigned int m = n;
1346         while (child) {
1347                 unsigned int c = check_delta_limit(child, n + 1);
1348                 if (m < c)
1349                         m = c;
1350                 child = child->delta_sibling;
1351         }
1352         return m;
1353 }
1354
1355 static unsigned long free_unpacked(struct unpacked *n)
1356 {
1357         unsigned long freed_mem = sizeof_delta_index(n->index);
1358         free_delta_index(n->index);
1359         n->index = NULL;
1360         if (n->data) {
1361                 freed_mem += n->entry->size;
1362                 free(n->data);
1363                 n->data = NULL;
1364         }
1365         n->entry = NULL;
1366         n->depth = 0;
1367         return freed_mem;
1368 }
1369
1370 static void find_deltas(struct object_entry **list, unsigned *list_size,
1371                         int window, int depth, unsigned *processed)
1372 {
1373         uint32_t i, idx = 0, count = 0;
1374         unsigned int array_size = window * sizeof(struct unpacked);
1375         struct unpacked *array;
1376         unsigned long mem_usage = 0;
1377
1378         array = xmalloc(array_size);
1379         memset(array, 0, array_size);
1380
1381         for (;;) {
1382                 struct object_entry *entry = *list++;
1383                 struct unpacked *n = array + idx;
1384                 int j, max_depth, best_base = -1;
1385
1386                 progress_lock();
1387                 if (!*list_size) {
1388                         progress_unlock();
1389                         break;
1390                 }
1391                 (*list_size)--;
1392                 if (!entry->preferred_base) {
1393                         (*processed)++;
1394                         display_progress(progress_state, *processed);
1395                 }
1396                 progress_unlock();
1397
1398                 mem_usage -= free_unpacked(n);
1399                 n->entry = entry;
1400
1401                 while (window_memory_limit &&
1402                        mem_usage > window_memory_limit &&
1403                        count > 1) {
1404                         uint32_t tail = (idx + window - count) % window;
1405                         mem_usage -= free_unpacked(array + tail);
1406                         count--;
1407                 }
1408
1409                 /* We do not compute delta to *create* objects we are not
1410                  * going to pack.
1411                  */
1412                 if (entry->preferred_base)
1413                         goto next;
1414
1415                 /*
1416                  * If the current object is at pack edge, take the depth the
1417                  * objects that depend on the current object into account
1418                  * otherwise they would become too deep.
1419                  */
1420                 max_depth = depth;
1421                 if (entry->delta_child) {
1422                         max_depth -= check_delta_limit(entry, 0);
1423                         if (max_depth <= 0)
1424                                 goto next;
1425                 }
1426
1427                 j = window;
1428                 while (--j > 0) {
1429                         int ret;
1430                         uint32_t other_idx = idx + j;
1431                         struct unpacked *m;
1432                         if (other_idx >= window)
1433                                 other_idx -= window;
1434                         m = array + other_idx;
1435                         if (!m->entry)
1436                                 break;
1437                         ret = try_delta(n, m, max_depth, &mem_usage);
1438                         if (ret < 0)
1439                                 break;
1440                         else if (ret > 0)
1441                                 best_base = other_idx;
1442                 }
1443
1444                 /* if we made n a delta, and if n is already at max
1445                  * depth, leaving it in the window is pointless.  we
1446                  * should evict it first.
1447                  */
1448                 if (entry->delta && depth <= n->depth)
1449                         continue;
1450
1451                 /*
1452                  * Move the best delta base up in the window, after the
1453                  * currently deltified object, to keep it longer.  It will
1454                  * be the first base object to be attempted next.
1455                  */
1456                 if (entry->delta) {
1457                         struct unpacked swap = array[best_base];
1458                         int dist = (window + idx - best_base) % window;
1459                         int dst = best_base;
1460                         while (dist--) {
1461                                 int src = (dst + 1) % window;
1462                                 array[dst] = array[src];
1463                                 dst = src;
1464                         }
1465                         array[dst] = swap;
1466                 }
1467
1468                 next:
1469                 idx++;
1470                 if (count + 1 < window)
1471                         count++;
1472                 if (idx >= window)
1473                         idx = 0;
1474         }
1475
1476         for (i = 0; i < window; ++i) {
1477                 free_delta_index(array[i].index);
1478                 free(array[i].data);
1479         }
1480         free(array);
1481 }
1482
1483 #ifdef THREADED_DELTA_SEARCH
1484
1485 /*
1486  * The main thread waits on the condition that (at least) one of the workers
1487  * has stopped working (which is indicated in the .working member of
1488  * struct thread_params).
1489  * When a work thread has completed its work, it sets .working to 0 and
1490  * signals the main thread and waits on the condition that .data_ready
1491  * becomes 1.
1492  */
1493
1494 struct thread_params {
1495         pthread_t thread;
1496         struct object_entry **list;
1497         unsigned list_size;
1498         unsigned remaining;
1499         int window;
1500         int depth;
1501         int working;
1502         int data_ready;
1503         pthread_mutex_t mutex;
1504         pthread_cond_t cond;
1505         unsigned *processed;
1506 };
1507
1508 static pthread_cond_t progress_cond = PTHREAD_COND_INITIALIZER;
1509
1510 static void *threaded_find_deltas(void *arg)
1511 {
1512         struct thread_params *me = arg;
1513
1514         while (me->remaining) {
1515                 find_deltas(me->list, &me->remaining,
1516                             me->window, me->depth, me->processed);
1517
1518                 progress_lock();
1519                 me->working = 0;
1520                 pthread_cond_signal(&progress_cond);
1521                 progress_unlock();
1522
1523                 /*
1524                  * We must not set ->data_ready before we wait on the
1525                  * condition because the main thread may have set it to 1
1526                  * before we get here. In order to be sure that new
1527                  * work is available if we see 1 in ->data_ready, it
1528                  * was initialized to 0 before this thread was spawned
1529                  * and we reset it to 0 right away.
1530                  */
1531                 pthread_mutex_lock(&me->mutex);
1532                 while (!me->data_ready)
1533                         pthread_cond_wait(&me->cond, &me->mutex);
1534                 me->data_ready = 0;
1535                 pthread_mutex_unlock(&me->mutex);
1536         }
1537         /* leave ->working 1 so that this doesn't get more work assigned */
1538         return NULL;
1539 }
1540
1541 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1542                            int window, int depth, unsigned *processed)
1543 {
1544         struct thread_params p[delta_search_threads];
1545         int i, ret, active_threads = 0;
1546
1547         if (delta_search_threads <= 1) {
1548                 find_deltas(list, &list_size, window, depth, processed);
1549                 return;
1550         }
1551
1552         /* Partition the work amongst work threads. */
1553         for (i = 0; i < delta_search_threads; i++) {
1554                 unsigned sub_size = list_size / (delta_search_threads - i);
1555
1556                 p[i].window = window;
1557                 p[i].depth = depth;
1558                 p[i].processed = processed;
1559                 p[i].working = 1;
1560                 p[i].data_ready = 0;
1561
1562                 /* try to split chunks on "path" boundaries */
1563                 while (sub_size && sub_size < list_size &&
1564                        list[sub_size]->hash &&
1565                        list[sub_size]->hash == list[sub_size-1]->hash)
1566                         sub_size++;
1567
1568                 p[i].list = list;
1569                 p[i].list_size = sub_size;
1570                 p[i].remaining = sub_size;
1571
1572                 list += sub_size;
1573                 list_size -= sub_size;
1574         }
1575
1576         /* Start work threads. */
1577         for (i = 0; i < delta_search_threads; i++) {
1578                 if (!p[i].list_size)
1579                         continue;
1580                 pthread_mutex_init(&p[i].mutex, NULL);
1581                 pthread_cond_init(&p[i].cond, NULL);
1582                 ret = pthread_create(&p[i].thread, NULL,
1583                                      threaded_find_deltas, &p[i]);
1584                 if (ret)
1585                         die("unable to create thread: %s", strerror(ret));
1586                 active_threads++;
1587         }
1588
1589         /*
1590          * Now let's wait for work completion.  Each time a thread is done
1591          * with its work, we steal half of the remaining work from the
1592          * thread with the largest number of unprocessed objects and give
1593          * it to that newly idle thread.  This ensure good load balancing
1594          * until the remaining object list segments are simply too short
1595          * to be worth splitting anymore.
1596          */
1597         while (active_threads) {
1598                 struct thread_params *target = NULL;
1599                 struct thread_params *victim = NULL;
1600                 unsigned sub_size = 0;
1601
1602                 progress_lock();
1603                 for (;;) {
1604                         for (i = 0; !target && i < delta_search_threads; i++)
1605                                 if (!p[i].working)
1606                                         target = &p[i];
1607                         if (target)
1608                                 break;
1609                         pthread_cond_wait(&progress_cond, &progress_mutex);
1610                 }
1611
1612                 for (i = 0; i < delta_search_threads; i++)
1613                         if (p[i].remaining > 2*window &&
1614                             (!victim || victim->remaining < p[i].remaining))
1615                                 victim = &p[i];
1616                 if (victim) {
1617                         sub_size = victim->remaining / 2;
1618                         list = victim->list + victim->list_size - sub_size;
1619                         while (sub_size && list[0]->hash &&
1620                                list[0]->hash == list[-1]->hash) {
1621                                 list++;
1622                                 sub_size--;
1623                         }
1624                         if (!sub_size) {
1625                                 /*
1626                                  * It is possible for some "paths" to have
1627                                  * so many objects that no hash boundary
1628                                  * might be found.  Let's just steal the
1629                                  * exact half in that case.
1630                                  */
1631                                 sub_size = victim->remaining / 2;
1632                                 list -= sub_size;
1633                         }
1634                         target->list = list;
1635                         victim->list_size -= sub_size;
1636                         victim->remaining -= sub_size;
1637                 }
1638                 target->list_size = sub_size;
1639                 target->remaining = sub_size;
1640                 target->working = 1;
1641                 progress_unlock();
1642
1643                 pthread_mutex_lock(&target->mutex);
1644                 target->data_ready = 1;
1645                 pthread_cond_signal(&target->cond);
1646                 pthread_mutex_unlock(&target->mutex);
1647
1648                 if (!sub_size) {
1649                         pthread_join(target->thread, NULL);
1650                         pthread_cond_destroy(&target->cond);
1651                         pthread_mutex_destroy(&target->mutex);
1652                         active_threads--;
1653                 }
1654         }
1655 }
1656
1657 #else
1658 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
1659 #endif
1660
1661 static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1662 {
1663         unsigned char peeled[20];
1664
1665         if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
1666             !peel_ref(path, peeled)        && /* peelable? */
1667             !is_null_sha1(peeled)          && /* annotated tag? */
1668             locate_object_entry(peeled))      /* object packed? */
1669                 add_object_entry(sha1, OBJ_TAG, NULL, 0);
1670         return 0;
1671 }
1672
1673 static void prepare_pack(int window, int depth)
1674 {
1675         struct object_entry **delta_list;
1676         uint32_t i, n, nr_deltas;
1677
1678         get_object_details();
1679
1680         if (!nr_objects || !window || !depth)
1681                 return;
1682
1683         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1684         nr_deltas = n = 0;
1685
1686         for (i = 0; i < nr_objects; i++) {
1687                 struct object_entry *entry = objects + i;
1688
1689                 if (entry->delta)
1690                         /* This happens if we decided to reuse existing
1691                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1692                          */
1693                         continue;
1694
1695                 if (entry->size < 50)
1696                         continue;
1697
1698                 if (entry->no_try_delta)
1699                         continue;
1700
1701                 if (!entry->preferred_base)
1702                         nr_deltas++;
1703
1704                 delta_list[n++] = entry;
1705         }
1706
1707         if (nr_deltas && n > 1) {
1708                 unsigned nr_done = 0;
1709                 if (progress)
1710                         progress_state = start_progress("Compressing objects",
1711                                                         nr_deltas);
1712                 qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
1713                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
1714                 stop_progress(&progress_state);
1715                 if (nr_done != nr_deltas)
1716                         die("inconsistency with delta count");
1717         }
1718         free(delta_list);
1719 }
1720
1721 static int git_pack_config(const char *k, const char *v)
1722 {
1723         if(!strcmp(k, "pack.window")) {
1724                 window = git_config_int(k, v);
1725                 return 0;
1726         }
1727         if (!strcmp(k, "pack.windowmemory")) {
1728                 window_memory_limit = git_config_ulong(k, v);
1729                 return 0;
1730         }
1731         if (!strcmp(k, "pack.depth")) {
1732                 depth = git_config_int(k, v);
1733                 return 0;
1734         }
1735         if (!strcmp(k, "pack.compression")) {
1736                 int level = git_config_int(k, v);
1737                 if (level == -1)
1738                         level = Z_DEFAULT_COMPRESSION;
1739                 else if (level < 0 || level > Z_BEST_COMPRESSION)
1740                         die("bad pack compression level %d", level);
1741                 pack_compression_level = level;
1742                 pack_compression_seen = 1;
1743                 return 0;
1744         }
1745         if (!strcmp(k, "pack.deltacachesize")) {
1746                 max_delta_cache_size = git_config_int(k, v);
1747                 return 0;
1748         }
1749         if (!strcmp(k, "pack.deltacachelimit")) {
1750                 cache_max_small_delta_size = git_config_int(k, v);
1751                 return 0;
1752         }
1753         if (!strcmp(k, "pack.threads")) {
1754                 delta_search_threads = git_config_int(k, v);
1755                 if (delta_search_threads < 0)
1756                         die("invalid number of threads specified (%d)",
1757                             delta_search_threads);
1758 #ifndef THREADED_DELTA_SEARCH
1759                 if (delta_search_threads != 1)
1760                         warning("no threads support, ignoring %s", k);
1761 #endif
1762                 return 0;
1763         }
1764         if (!strcmp(k, "pack.indexversion")) {
1765                 pack_idx_default_version = git_config_int(k, v);
1766                 if (pack_idx_default_version > 2)
1767                         die("bad pack.indexversion=%d", pack_idx_default_version);
1768                 return 0;
1769         }
1770         if (!strcmp(k, "pack.packsizelimit")) {
1771                 pack_size_limit_cfg = git_config_ulong(k, v);
1772                 return 0;
1773         }
1774         return git_default_config(k, v);
1775 }
1776
1777 static void read_object_list_from_stdin(void)
1778 {
1779         char line[40 + 1 + PATH_MAX + 2];
1780         unsigned char sha1[20];
1781
1782         for (;;) {
1783                 if (!fgets(line, sizeof(line), stdin)) {
1784                         if (feof(stdin))
1785                                 break;
1786                         if (!ferror(stdin))
1787                                 die("fgets returned NULL, not EOF, not error!");
1788                         if (errno != EINTR)
1789                                 die("fgets: %s", strerror(errno));
1790                         clearerr(stdin);
1791                         continue;
1792                 }
1793                 if (line[0] == '-') {
1794                         if (get_sha1_hex(line+1, sha1))
1795                                 die("expected edge sha1, got garbage:\n %s",
1796                                     line);
1797                         add_preferred_base(sha1);
1798                         continue;
1799                 }
1800                 if (get_sha1_hex(line, sha1))
1801                         die("expected sha1, got garbage:\n %s", line);
1802
1803                 add_preferred_base_object(line+41);
1804                 add_object_entry(sha1, 0, line+41, 0);
1805         }
1806 }
1807
1808 #define OBJECT_ADDED (1u<<20)
1809
1810 static void show_commit(struct commit *commit)
1811 {
1812         add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
1813         commit->object.flags |= OBJECT_ADDED;
1814 }
1815
1816 static void show_object(struct object_array_entry *p)
1817 {
1818         add_preferred_base_object(p->name);
1819         add_object_entry(p->item->sha1, p->item->type, p->name, 0);
1820         p->item->flags |= OBJECT_ADDED;
1821 }
1822
1823 static void show_edge(struct commit *commit)
1824 {
1825         add_preferred_base(commit->object.sha1);
1826 }
1827
1828 struct in_pack_object {
1829         off_t offset;
1830         struct object *object;
1831 };
1832
1833 struct in_pack {
1834         int alloc;
1835         int nr;
1836         struct in_pack_object *array;
1837 };
1838
1839 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
1840 {
1841         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
1842         in_pack->array[in_pack->nr].object = object;
1843         in_pack->nr++;
1844 }
1845
1846 /*
1847  * Compare the objects in the offset order, in order to emulate the
1848  * "git-rev-list --objects" output that produced the pack originally.
1849  */
1850 static int ofscmp(const void *a_, const void *b_)
1851 {
1852         struct in_pack_object *a = (struct in_pack_object *)a_;
1853         struct in_pack_object *b = (struct in_pack_object *)b_;
1854
1855         if (a->offset < b->offset)
1856                 return -1;
1857         else if (a->offset > b->offset)
1858                 return 1;
1859         else
1860                 return hashcmp(a->object->sha1, b->object->sha1);
1861 }
1862
1863 static void add_objects_in_unpacked_packs(struct rev_info *revs)
1864 {
1865         struct packed_git *p;
1866         struct in_pack in_pack;
1867         uint32_t i;
1868
1869         memset(&in_pack, 0, sizeof(in_pack));
1870
1871         for (p = packed_git; p; p = p->next) {
1872                 const unsigned char *sha1;
1873                 struct object *o;
1874
1875                 for (i = 0; i < revs->num_ignore_packed; i++) {
1876                         if (matches_pack_name(p, revs->ignore_packed[i]))
1877                                 break;
1878                 }
1879                 if (revs->num_ignore_packed <= i)
1880                         continue;
1881                 if (open_pack_index(p))
1882                         die("cannot open pack index");
1883
1884                 ALLOC_GROW(in_pack.array,
1885                            in_pack.nr + p->num_objects,
1886                            in_pack.alloc);
1887
1888                 for (i = 0; i < p->num_objects; i++) {
1889                         sha1 = nth_packed_object_sha1(p, i);
1890                         o = lookup_unknown_object(sha1);
1891                         if (!(o->flags & OBJECT_ADDED))
1892                                 mark_in_pack_object(o, p, &in_pack);
1893                         o->flags |= OBJECT_ADDED;
1894                 }
1895         }
1896
1897         if (in_pack.nr) {
1898                 qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
1899                       ofscmp);
1900                 for (i = 0; i < in_pack.nr; i++) {
1901                         struct object *o = in_pack.array[i].object;
1902                         add_object_entry(o->sha1, o->type, "", 0);
1903                 }
1904         }
1905         free(in_pack.array);
1906 }
1907
1908 static void get_object_list(int ac, const char **av)
1909 {
1910         struct rev_info revs;
1911         char line[1000];
1912         int flags = 0;
1913
1914         init_revisions(&revs, NULL);
1915         save_commit_buffer = 0;
1916         setup_revisions(ac, av, &revs, NULL);
1917
1918         while (fgets(line, sizeof(line), stdin) != NULL) {
1919                 int len = strlen(line);
1920                 if (len && line[len - 1] == '\n')
1921                         line[--len] = 0;
1922                 if (!len)
1923                         break;
1924                 if (*line == '-') {
1925                         if (!strcmp(line, "--not")) {
1926                                 flags ^= UNINTERESTING;
1927                                 continue;
1928                         }
1929                         die("not a rev '%s'", line);
1930                 }
1931                 if (handle_revision_arg(line, &revs, flags, 1))
1932                         die("bad revision '%s'", line);
1933         }
1934
1935         if (prepare_revision_walk(&revs))
1936                 die("revision walk setup failed");
1937         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1938         traverse_commit_list(&revs, show_commit, show_object);
1939
1940         if (keep_unreachable)
1941                 add_objects_in_unpacked_packs(&revs);
1942 }
1943
1944 static int adjust_perm(const char *path, mode_t mode)
1945 {
1946         if (chmod(path, mode))
1947                 return -1;
1948         return adjust_shared_perm(path);
1949 }
1950
1951 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1952 {
1953         int use_internal_rev_list = 0;
1954         int thin = 0;
1955         uint32_t i;
1956         const char **rp_av;
1957         int rp_ac_alloc = 64;
1958         int rp_ac;
1959
1960         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1961
1962         rp_av[0] = "pack-objects";
1963         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1964         rp_ac = 2;
1965
1966         git_config(git_pack_config);
1967         if (!pack_compression_seen && core_compression_seen)
1968                 pack_compression_level = core_compression_level;
1969
1970         progress = isatty(2);
1971         for (i = 1; i < argc; i++) {
1972                 const char *arg = argv[i];
1973
1974                 if (*arg != '-')
1975                         break;
1976
1977                 if (!strcmp("--non-empty", arg)) {
1978                         non_empty = 1;
1979                         continue;
1980                 }
1981                 if (!strcmp("--local", arg)) {
1982                         local = 1;
1983                         continue;
1984                 }
1985                 if (!strcmp("--incremental", arg)) {
1986                         incremental = 1;
1987                         continue;
1988                 }
1989                 if (!prefixcmp(arg, "--compression=")) {
1990                         char *end;
1991                         int level = strtoul(arg+14, &end, 0);
1992                         if (!arg[14] || *end)
1993                                 usage(pack_usage);
1994                         if (level == -1)
1995                                 level = Z_DEFAULT_COMPRESSION;
1996                         else if (level < 0 || level > Z_BEST_COMPRESSION)
1997                                 die("bad pack compression level %d", level);
1998                         pack_compression_level = level;
1999                         continue;
2000                 }
2001                 if (!prefixcmp(arg, "--max-pack-size=")) {
2002                         char *end;
2003                         pack_size_limit_cfg = 0;
2004                         pack_size_limit = strtoul(arg+16, &end, 0) * 1024 * 1024;
2005                         if (!arg[16] || *end)
2006                                 usage(pack_usage);
2007                         continue;
2008                 }
2009                 if (!prefixcmp(arg, "--window=")) {
2010                         char *end;
2011                         window = strtoul(arg+9, &end, 0);
2012                         if (!arg[9] || *end)
2013                                 usage(pack_usage);
2014                         continue;
2015                 }
2016                 if (!prefixcmp(arg, "--window-memory=")) {
2017                         if (!git_parse_ulong(arg+16, &window_memory_limit))
2018                                 usage(pack_usage);
2019                         continue;
2020                 }
2021                 if (!prefixcmp(arg, "--threads=")) {
2022                         char *end;
2023                         delta_search_threads = strtoul(arg+10, &end, 0);
2024                         if (!arg[10] || *end || delta_search_threads < 0)
2025                                 usage(pack_usage);
2026 #ifndef THREADED_DELTA_SEARCH
2027                         if (delta_search_threads != 1)
2028                                 warning("no threads support, "
2029                                         "ignoring %s", arg);
2030 #endif
2031                         continue;
2032                 }
2033                 if (!prefixcmp(arg, "--depth=")) {
2034                         char *end;
2035                         depth = strtoul(arg+8, &end, 0);
2036                         if (!arg[8] || *end)
2037                                 usage(pack_usage);
2038                         continue;
2039                 }
2040                 if (!strcmp("--progress", arg)) {
2041                         progress = 1;
2042                         continue;
2043                 }
2044                 if (!strcmp("--all-progress", arg)) {
2045                         progress = 2;
2046                         continue;
2047                 }
2048                 if (!strcmp("-q", arg)) {
2049                         progress = 0;
2050                         continue;
2051                 }
2052                 if (!strcmp("--no-reuse-delta", arg)) {
2053                         no_reuse_delta = 1;
2054                         continue;
2055                 }
2056                 if (!strcmp("--no-reuse-object", arg)) {
2057                         no_reuse_object = no_reuse_delta = 1;
2058                         continue;
2059                 }
2060                 if (!strcmp("--delta-base-offset", arg)) {
2061                         allow_ofs_delta = 1;
2062                         continue;
2063                 }
2064                 if (!strcmp("--stdout", arg)) {
2065                         pack_to_stdout = 1;
2066                         continue;
2067                 }
2068                 if (!strcmp("--revs", arg)) {
2069                         use_internal_rev_list = 1;
2070                         continue;
2071                 }
2072                 if (!strcmp("--keep-unreachable", arg)) {
2073                         keep_unreachable = 1;
2074                         continue;
2075                 }
2076                 if (!strcmp("--include-tag", arg)) {
2077                         include_tag = 1;
2078                         continue;
2079                 }
2080                 if (!strcmp("--unpacked", arg) ||
2081                     !prefixcmp(arg, "--unpacked=") ||
2082                     !strcmp("--reflog", arg) ||
2083                     !strcmp("--all", arg)) {
2084                         use_internal_rev_list = 1;
2085                         if (rp_ac >= rp_ac_alloc - 1) {
2086                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
2087                                 rp_av = xrealloc(rp_av,
2088                                                  rp_ac_alloc * sizeof(*rp_av));
2089                         }
2090                         rp_av[rp_ac++] = arg;
2091                         continue;
2092                 }
2093                 if (!strcmp("--thin", arg)) {
2094                         use_internal_rev_list = 1;
2095                         thin = 1;
2096                         rp_av[1] = "--objects-edge";
2097                         continue;
2098                 }
2099                 if (!prefixcmp(arg, "--index-version=")) {
2100                         char *c;
2101                         pack_idx_default_version = strtoul(arg + 16, &c, 10);
2102                         if (pack_idx_default_version > 2)
2103                                 die("bad %s", arg);
2104                         if (*c == ',')
2105                                 pack_idx_off32_limit = strtoul(c+1, &c, 0);
2106                         if (*c || pack_idx_off32_limit & 0x80000000)
2107                                 die("bad %s", arg);
2108                         continue;
2109                 }
2110                 usage(pack_usage);
2111         }
2112
2113         /* Traditionally "pack-objects [options] base extra" failed;
2114          * we would however want to take refs parameter that would
2115          * have been given to upstream rev-list ourselves, which means
2116          * we somehow want to say what the base name is.  So the
2117          * syntax would be:
2118          *
2119          * pack-objects [options] base <refs...>
2120          *
2121          * in other words, we would treat the first non-option as the
2122          * base_name and send everything else to the internal revision
2123          * walker.
2124          */
2125
2126         if (!pack_to_stdout)
2127                 base_name = argv[i++];
2128
2129         if (pack_to_stdout != !base_name)
2130                 usage(pack_usage);
2131
2132         if (!pack_to_stdout && !pack_size_limit)
2133                 pack_size_limit = pack_size_limit_cfg;
2134
2135         if (pack_to_stdout && pack_size_limit)
2136                 die("--max-pack-size cannot be used to build a pack for transfer.");
2137
2138         if (!pack_to_stdout && thin)
2139                 die("--thin cannot be used to build an indexable pack.");
2140
2141 #ifdef THREADED_DELTA_SEARCH
2142         if (!delta_search_threads)      /* --threads=0 means autodetect */
2143                 delta_search_threads = online_cpus();
2144 #endif
2145
2146         prepare_packed_git();
2147
2148         if (progress)
2149                 progress_state = start_progress("Counting objects", 0);
2150         if (!use_internal_rev_list)
2151                 read_object_list_from_stdin();
2152         else {
2153                 rp_av[rp_ac] = NULL;
2154                 get_object_list(rp_ac, rp_av);
2155         }
2156         if (include_tag && nr_result)
2157                 for_each_ref(add_ref_tag, NULL);
2158         stop_progress(&progress_state);
2159
2160         if (non_empty && !nr_result)
2161                 return 0;
2162         if (nr_result)
2163                 prepare_pack(window, depth);
2164         write_pack_file();
2165         if (progress)
2166                 fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
2167                         written, written_delta, reused, reused_delta);
2168         return 0;
2169 }