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   "        [--all-progress-implied]\n"
  28   "        [--max-pack-size=N] [--local] [--incremental]\n"
  29   "        [--window=N] [--window-memory=N] [--depth=N]\n"
  30   "        [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset]\n"
  31   "        [--threads=N] [--non-empty] [--revs [--unpacked | --all]*]\n"
  32   "        [--reflog] [--stdout | base-name] [--include-tag]\n"
  33   "        [--keep-unreachable | --unpack-unreachable \n"
  34   "        [<ref-list | <object-list]";
  35
  36 struct object_entry {
  37         struct pack_idx_entry idx;
  38         unsigned long size;     /* uncompressed size */
  39         struct packed_git *in_pack;     /* already in pack */
  40         off_t in_pack_offset;
  41         struct object_entry *delta;     /* delta base object */
  42         struct object_entry *delta_child; /* deltified objects who bases me */
  43         struct object_entry *delta_sibling; /* other deltified objects who
  44                                              * uses the same base as me
  45                                              */
  46         void *delta_data;       /* cached delta (uncompressed) */
  47         unsigned long delta_size;       /* delta data size (uncompressed) */
  48         unsigned long z_delta_size;     /* delta data size (compressed) */
  49         unsigned int hash;      /* name hint hash */
  50         enum object_type type;
  51         enum object_type in_pack_type;  /* could be delta */
  52         unsigned char in_pack_header_size;
  53         unsigned char preferred_base; /* we do not pack this, but is available
  54                                        * to be used as the base object to delta
  55                                        * objects against.
  56                                        */
  57         unsigned char no_try_delta;
  58 };
  59
  60 /*
  61  * Objects we are going to pack are collected in objects array (dynamically
  62  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  63  * in the order we see -- typically rev-list --objects order that gives us
  64  * nice "minimum seek" order.
  65  */
  66 static struct object_entry *objects;
  67 static struct pack_idx_entry **written_list;
  68 static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  69
  70 static int non_empty;
  71 static int reuse_delta = 1, reuse_object = 1;
  72 static int keep_unreachable, unpack_unreachable, include_tag;
  73 static int local;
  74 static int incremental;
  75 static int ignore_packed_keep;
  76 static int allow_ofs_delta;
  77 static const char *base_name;
  78 static int progress = 1;
  79 static int window = 10;
  80 static uint32_t pack_size_limit, pack_size_limit_cfg;
  81 static int depth = 50;
  82 static int delta_search_threads;
  83 static int pack_to_stdout;
  84 static int num_preferred_base;
  85 static struct progress *progress_state;
  86 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  87 static int pack_compression_seen;
  88
  89 static unsigned long delta_cache_size = 0;
  90 static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  91 static unsigned long cache_max_small_delta_size = 1000;
  92
  93 static unsigned long window_memory_limit = 0;
  94
  95 /*
  96  * The object names in objects array are hashed with this hashtable,
  97  * to help looking up the entry by object name.
  98  * This hashtable is built after all the objects are seen.
  99  */
 100 static int *object_ix;
 101 static int object_ix_hashsz;
 102
 103 /*
 104  * stats
 105  */
 106 static uint32_t written, written_delta;
 107 static uint32_t reused, reused_delta;
 108
 109
 110 static void *get_delta(struct object_entry *entry)
 111 {
 112         unsigned long size, base_size, delta_size;
 113         void *buf, *base_buf, *delta_buf;
 114         enum object_type type;
 115
 116         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 117         if (!buf)
 118                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 119         base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
 120         if (!base_buf)
 121                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 122         delta_buf = diff_delta(base_buf, base_size,
 123                                buf, size, &delta_size, 0);
 124         if (!delta_buf || delta_size != entry->delta_size)
 125                 die("delta size changed");
 126         free(buf);
 127         free(base_buf);
 128         return delta_buf;
 129 }
 130
 131 static unsigned long do_compress(void **pptr, unsigned long size)
 132 {
 133         z_stream stream;
 134         void *in, *out;
 135         unsigned long maxsize;
 136
 137         memset(&stream, 0, sizeof(stream));
 138         deflateInit(&stream, pack_compression_level);
 139         maxsize = deflateBound(&stream, size);
 140
 141         in = *pptr;
 142         out = xmalloc(maxsize);
 143         *pptr = out;
 144
 145         stream.next_in = in;
 146         stream.avail_in = size;
 147         stream.next_out = out;
 148         stream.avail_out = maxsize;
 149         while (deflate(&stream, Z_FINISH) == Z_OK)
 150                 ; /* nothing */
 151         deflateEnd(&stream);
 152
 153         free(in);
 154         return stream.total_out;
 155 }
 156
 157 /*
 158  * The per-object header is a pretty dense thing, which is
 159  *  - first byte: low four bits are "size", then three bits of "type",
 160  *    and the high bit is "size continues".
 161  *  - each byte afterwards: low seven bits are size continuation,
 162  *    with the high bit being "size continues"
 163  */
 164 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 165 {
 166         int n = 1;
 167         unsigned char c;
 168
 169         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 170                 die("bad type %d", type);
 171
 172         c = (type << 4) | (size & 15);
 173         size >>= 4;
 174         while (size) {
 175                 *hdr++ = c | 0x80;
 176                 c = size & 0x7f;
 177                 size >>= 7;
 178                 n++;
 179         }
 180         *hdr = c;
 181         return n;
 182 }
 183
 184 /*
 185  * we are going to reuse the existing object data as is.  make
 186  * sure it is not corrupt.
 187  */
 188 static int check_pack_inflate(struct packed_git *p,
 189                 struct pack_window **w_curs,
 190                 off_t offset,
 191                 off_t len,
 192                 unsigned long expect)
 193 {
 194         z_stream stream;
 195         unsigned char fakebuf[4096], *in;
 196         int st;
 197
 198         memset(&stream, 0, sizeof(stream));
 199         git_inflate_init(&stream);
 200         do {
 201                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 202                 stream.next_in = in;
 203                 stream.next_out = fakebuf;
 204                 stream.avail_out = sizeof(fakebuf);
 205                 st = git_inflate(&stream, Z_FINISH);
 206                 offset += stream.next_in - in;
 207         } while (st == Z_OK || st == Z_BUF_ERROR);
 208         git_inflate_end(&stream);
 209         return (st == Z_STREAM_END &&
 210                 stream.total_out == expect &&
 211                 stream.total_in == len) ? 0 : -1;
 212 }
 213
 214 static void copy_pack_data(struct sha1file *f,
 215                 struct packed_git *p,
 216                 struct pack_window **w_curs,
 217                 off_t offset,
 218                 off_t len)
 219 {
 220         unsigned char *in;
 221         unsigned int avail;
 222
 223         while (len) {
 224                 in = use_pack(p, w_curs, offset, &avail);
 225                 if (avail > len)
 226                         avail = (unsigned int)len;
 227                 sha1write(f, in, avail);
 228                 offset += avail;
 229                 len -= avail;
 230         }
 231 }
 232
 233 static unsigned long write_object(struct sha1file *f,
 234                                   struct object_entry *entry,
 235                                   off_t write_offset)
 236 {
 237         unsigned long size, limit, datalen;
 238         void *buf;
 239         unsigned char header[10], dheader[10];
 240         unsigned hdrlen;
 241         enum object_type type;
 242         int usable_delta, to_reuse;
 243
 244         if (!pack_to_stdout)
 245                 crc32_begin(f);
 246
 247         type = entry->type;
 248
 249         /* write limit if limited packsize and not first object */
 250         if (!pack_size_limit || !nr_written)
 251                 limit = 0;
 252         else if (pack_size_limit <= write_offset)
 253                 /*
 254                  * the earlier object did not fit the limit; avoid
 255                  * mistaking this with unlimited (i.e. limit = 0).
 256                  */
 257                 limit = 1;
 258         else
 259                 limit = pack_size_limit - write_offset;
 260
 261         if (!entry->delta)
 262                 usable_delta = 0;       /* no delta */
 263         else if (!pack_size_limit)
 264                usable_delta = 1;        /* unlimited packfile */
 265         else if (entry->delta->idx.offset == (off_t)-1)
 266                 usable_delta = 0;       /* base was written to another pack */
 267         else if (entry->delta->idx.offset)
 268                 usable_delta = 1;       /* base already exists in this pack */
 269         else
 270                 usable_delta = 0;       /* base could end up in another pack */
 271
 272         if (!reuse_object)
 273                 to_reuse = 0;   /* explicit */
 274         else if (!entry->in_pack)
 275                 to_reuse = 0;   /* can't reuse what we don't have */
 276         else if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA)
 277                                 /* check_object() decided it for us ... */
 278                 to_reuse = usable_delta;
 279                                 /* ... but pack split may override that */
 280         else if (type != entry->in_pack_type)
 281                 to_reuse = 0;   /* pack has delta which is unusable */
 282         else if (entry->delta)
 283                 to_reuse = 0;   /* we want to pack afresh */
 284         else
 285                 to_reuse = 1;   /* we have it in-pack undeltified,
 286                                  * and we do not need to deltify it.
 287                                  */
 288
 289         if (!to_reuse) {
 290                 no_reuse:
 291                 if (!usable_delta) {
 292                         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 293                         if (!buf)
 294                                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 295                         /*
 296                          * make sure no cached delta data remains from a
 297                          * previous attempt before a pack split occurred.
 298                          */
 299                         free(entry->delta_data);
 300                         entry->delta_data = NULL;
 301                         entry->z_delta_size = 0;
 302                 } else if (entry->delta_data) {
 303                         size = entry->delta_size;
 304                         buf = entry->delta_data;
 305                         entry->delta_data = NULL;
 306                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 307                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 308                 } else {
 309                         buf = get_delta(entry);
 310                         size = entry->delta_size;
 311                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 312                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 313                 }
 314
 315                 if (entry->z_delta_size)
 316                         datalen = entry->z_delta_size;
 317                 else
 318                         datalen = do_compress(&buf, size);
 319
 320                 /*
 321                  * The object header is a byte of 'type' followed by zero or
 322                  * more bytes of length.
 323                  */
 324                 hdrlen = encode_header(type, size, header);
 325
 326                 if (type == OBJ_OFS_DELTA) {
 327                         /*
 328                          * Deltas with relative base contain an additional
 329                          * encoding of the relative offset for the delta
 330                          * base from this object's position in the pack.
 331                          */
 332                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 333                         unsigned pos = sizeof(dheader) - 1;
 334                         dheader[pos] = ofs & 127;
 335                         while (ofs >>= 7)
 336                                 dheader[--pos] = 128 | (--ofs & 127);
 337                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 338                                 free(buf);
 339                                 return 0;
 340                         }
 341                         sha1write(f, header, hdrlen);
 342                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 343                         hdrlen += sizeof(dheader) - pos;
 344                 } else if (type == OBJ_REF_DELTA) {
 345                         /*
 346                          * Deltas with a base reference contain
 347                          * an additional 20 bytes for the base sha1.
 348                          */
 349                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 350                                 free(buf);
 351                                 return 0;
 352                         }
 353                         sha1write(f, header, hdrlen);
 354                         sha1write(f, entry->delta->idx.sha1, 20);
 355                         hdrlen += 20;
 356                 } else {
 357                         if (limit && hdrlen + datalen + 20 >= limit) {
 358                                 free(buf);
 359                                 return 0;
 360                         }
 361                         sha1write(f, header, hdrlen);
 362                 }
 363                 sha1write(f, buf, datalen);
 364                 free(buf);
 365         }
 366         else {
 367                 struct packed_git *p = entry->in_pack;
 368                 struct pack_window *w_curs = NULL;
 369                 struct revindex_entry *revidx;
 370                 off_t offset;
 371
 372                 if (entry->delta)
 373                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 374                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 375                 hdrlen = encode_header(type, entry->size, header);
 376
 377                 offset = entry->in_pack_offset;
 378                 revidx = find_pack_revindex(p, offset);
 379                 datalen = revidx[1].offset - offset;
 380                 if (!pack_to_stdout && p->index_version > 1 &&
 381                     check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 382                         error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 383                         unuse_pack(&w_curs);
 384                         goto no_reuse;
 385                 }
 386
 387                 offset += entry->in_pack_header_size;
 388                 datalen -= entry->in_pack_header_size;
 389                 if (!pack_to_stdout && p->index_version == 1 &&
 390                     check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 391                         error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 392                         unuse_pack(&w_curs);
 393                         goto no_reuse;
 394                 }
 395
 396                 if (type == OBJ_OFS_DELTA) {
 397                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 398                         unsigned pos = sizeof(dheader) - 1;
 399                         dheader[pos] = ofs & 127;
 400                         while (ofs >>= 7)
 401                                 dheader[--pos] = 128 | (--ofs & 127);
 402                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 403                                 unuse_pack(&w_curs);
 404                                 return 0;
 405                         }
 406                         sha1write(f, header, hdrlen);
 407                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 408                         hdrlen += sizeof(dheader) - pos;
 409                         reused_delta++;
 410                 } else if (type == OBJ_REF_DELTA) {
 411                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 412                                 unuse_pack(&w_curs);
 413                                 return 0;
 414                         }
 415                         sha1write(f, header, hdrlen);
 416                         sha1write(f, entry->delta->idx.sha1, 20);
 417                         hdrlen += 20;
 418                         reused_delta++;
 419                 } else {
 420                         if (limit && hdrlen + datalen + 20 >= limit) {
 421                                 unuse_pack(&w_curs);
 422                                 return 0;
 423                         }
 424                         sha1write(f, header, hdrlen);
 425                 }
 426                 copy_pack_data(f, p, &w_curs, offset, datalen);
 427                 unuse_pack(&w_curs);
 428                 reused++;
 429         }
 430         if (usable_delta)
 431                 written_delta++;
 432         written++;
 433         if (!pack_to_stdout)
 434                 entry->idx.crc32 = crc32_end(f);
 435         return hdrlen + datalen;
 436 }
 437
 438 static int write_one(struct sha1file *f,
 439                                struct object_entry *e,
 440                                off_t *offset)
 441 {
 442         unsigned long size;
 443
 444         /* offset is non zero if object is written already. */
 445         if (e->idx.offset || e->preferred_base)
 446                 return 1;
 447
 448         /* if we are deltified, write out base object first. */
 449         if (e->delta && !write_one(f, e->delta, offset))
 450                 return 0;
 451
 452         e->idx.offset = *offset;
 453         size = write_object(f, e, *offset);
 454         if (!size) {
 455                 e->idx.offset = 0;
 456                 return 0;
 457         }
 458         written_list[nr_written++] = &e->idx;
 459
 460         /* make sure off_t is sufficiently large not to wrap */
 461         if (*offset > *offset + size)
 462                 die("pack too large for current definition of off_t");
 463         *offset += size;
 464         return 1;
 465 }
 466
 467 /* forward declaration for write_pack_file */
 468 static int adjust_perm(const char *path, mode_t mode);
 469
 470 static void write_pack_file(void)
 471 {
 472         uint32_t i = 0, j;
 473         struct sha1file *f;
 474         off_t offset;
 475         struct pack_header hdr;
 476         uint32_t nr_remaining = nr_result;
 477         time_t last_mtime = 0;
 478
 479         if (progress > pack_to_stdout)
 480                 progress_state = start_progress("Writing objects", nr_result);
 481         written_list = xmalloc(nr_objects * sizeof(*written_list));
 482
 483         do {
 484                 unsigned char sha1[20];
 485                 char *pack_tmp_name = NULL;
 486
 487                 if (pack_to_stdout) {
 488                         f = sha1fd_throughput(1, "<stdout>", progress_state);
 489                 } else {
 490                         char tmpname[PATH_MAX];
 491                         int fd;
 492                         fd = odb_mkstemp(tmpname, sizeof(tmpname),
 493                                          "pack/tmp_pack_XXXXXX");
 494                         pack_tmp_name = xstrdup(tmpname);
 495                         f = sha1fd(fd, pack_tmp_name);
 496                 }
 497
 498                 hdr.hdr_signature = htonl(PACK_SIGNATURE);
 499                 hdr.hdr_version = htonl(PACK_VERSION);
 500                 hdr.hdr_entries = htonl(nr_remaining);
 501                 sha1write(f, &hdr, sizeof(hdr));
 502                 offset = sizeof(hdr);
 503                 nr_written = 0;
 504                 for (; i < nr_objects; i++) {
 505                         if (!write_one(f, objects + i, &offset))
 506                                 break;
 507                         display_progress(progress_state, written);
 508                 }
 509
 510                 /*
 511                  * Did we write the wrong # entries in the header?
 512                  * If so, rewrite it like in fast-import
 513                  */
 514                 if (pack_to_stdout) {
 515                         sha1close(f, sha1, CSUM_CLOSE);
 516                 } else if (nr_written == nr_remaining) {
 517                         sha1close(f, sha1, CSUM_FSYNC);
 518                 } else {
 519                         int fd = sha1close(f, sha1, 0);
 520                         fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 521                                                  nr_written, sha1, offset);
 522                         close(fd);
 523                 }
 524
 525                 if (!pack_to_stdout) {
 526                         mode_t mode = umask(0);
 527                         struct stat st;
 528                         char *idx_tmp_name, tmpname[PATH_MAX];
 529
 530                         umask(mode);
 531                         mode = 0444 & ~mode;
 532
 533                         idx_tmp_name = write_idx_file(NULL, written_list,
 534                                                       nr_written, sha1);
 535
 536                         snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
 537                                  base_name, sha1_to_hex(sha1));
 538                         free_pack_by_name(tmpname);
 539                         if (adjust_perm(pack_tmp_name, mode))
 540                                 die_errno("unable to make temporary pack file readable");
 541                         if (rename(pack_tmp_name, tmpname))
 542                                 die_errno("unable to rename temporary pack file");
 543
 544                         /*
 545                          * Packs are runtime accessed in their mtime
 546                          * order since newer packs are more likely to contain
 547                          * younger objects.  So if we are creating multiple
 548                          * packs then we should modify the mtime of later ones
 549                          * to preserve this property.
 550                          */
 551                         if (stat(tmpname, &st) < 0) {
 552                                 warning("failed to stat %s: %s",
 553                                         tmpname, strerror(errno));
 554                         } else if (!last_mtime) {
 555                                 last_mtime = st.st_mtime;
 556                         } else {
 557                                 struct utimbuf utb;
 558                                 utb.actime = st.st_atime;
 559                                 utb.modtime = --last_mtime;
 560                                 if (utime(tmpname, &utb) < 0)
 561                                         warning("failed utime() on %s: %s",
 562                                                 tmpname, strerror(errno));
 563                         }
 564
 565                         snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
 566                                  base_name, sha1_to_hex(sha1));
 567                         if (adjust_perm(idx_tmp_name, mode))
 568                                 die_errno("unable to make temporary index file readable");
 569                         if (rename(idx_tmp_name, tmpname))
 570                                 die_errno("unable to rename temporary index file");
 571
 572                         free(idx_tmp_name);
 573                         free(pack_tmp_name);
 574                         puts(sha1_to_hex(sha1));
 575                 }
 576
 577                 /* mark written objects as written to previous pack */
 578                 for (j = 0; j < nr_written; j++) {
 579                         written_list[j]->offset = (off_t)-1;
 580                 }
 581                 nr_remaining -= nr_written;
 582         } while (nr_remaining && i < nr_objects);
 583
 584         free(written_list);
 585         stop_progress(&progress_state);
 586         if (written != nr_result)
 587                 die("wrote %"PRIu32" objects while expecting %"PRIu32,
 588                         written, nr_result);
 589         /*
 590          * We have scanned through [0 ... i).  Since we have written
 591          * the correct number of objects,  the remaining [i ... nr_objects)
 592          * items must be either already written (due to out-of-order delta base)
 593          * or a preferred base.  Count those which are neither and complain if any.
 594          */
 595         for (j = 0; i < nr_objects; i++) {
 596                 struct object_entry *e = objects + i;
 597                 j += !e->idx.offset && !e->preferred_base;
 598         }
 599         if (j)
 600                 die("wrote %"PRIu32" objects as expected but %"PRIu32
 601                         " unwritten", written, j);
 602 }
 603
 604 static int locate_object_entry_hash(const unsigned char *sha1)
 605 {
 606         int i;
 607         unsigned int ui;
 608         memcpy(&ui, sha1, sizeof(unsigned int));
 609         i = ui % object_ix_hashsz;
 610         while (0 < object_ix[i]) {
 611                 if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 612                         return i;
 613                 if (++i == object_ix_hashsz)
 614                         i = 0;
 615         }
 616         return -1 - i;
 617 }
 618
 619 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 620 {
 621         int i;
 622
 623         if (!object_ix_hashsz)
 624                 return NULL;
 625
 626         i = locate_object_entry_hash(sha1);
 627         if (0 <= i)
 628                 return &objects[object_ix[i]-1];
 629         return NULL;
 630 }
 631
 632 static void rehash_objects(void)
 633 {
 634         uint32_t i;
 635         struct object_entry *oe;
 636
 637         object_ix_hashsz = nr_objects * 3;
 638         if (object_ix_hashsz < 1024)
 639                 object_ix_hashsz = 1024;
 640         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 641         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 642         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 643                 int ix = locate_object_entry_hash(oe->idx.sha1);
 644                 if (0 <= ix)
 645                         continue;
 646                 ix = -1 - ix;
 647                 object_ix[ix] = i + 1;
 648         }
 649 }
 650
 651 static unsigned name_hash(const char *name)
 652 {
 653         unsigned c, hash = 0;
 654
 655         if (!name)
 656                 return 0;
 657
 658         /*
 659          * This effectively just creates a sortable number from the
 660          * last sixteen non-whitespace characters. Last characters
 661          * count "most", so things that end in ".c" sort together.
 662          */
 663         while ((c = *name++) != 0) {
 664                 if (isspace(c))
 665                         continue;
 666                 hash = (hash >> 2) + (c << 24);
 667         }
 668         return hash;
 669 }
 670
 671 static void setup_delta_attr_check(struct git_attr_check *check)
 672 {
 673         static struct git_attr *attr_delta;
 674
 675         if (!attr_delta)
 676                 attr_delta = git_attr("delta", 5);
 677
 678         check[0].attr = attr_delta;
 679 }
 680
 681 static int no_try_delta(const char *path)
 682 {
 683         struct git_attr_check check[1];
 684
 685         setup_delta_attr_check(check);
 686         if (git_checkattr(path, ARRAY_SIZE(check), check))
 687                 return 0;
 688         if (ATTR_FALSE(check->value))
 689                 return 1;
 690         return 0;
 691 }
 692
 693 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 694                             const char *name, int exclude)
 695 {
 696         struct object_entry *entry;
 697         struct packed_git *p, *found_pack = NULL;
 698         off_t found_offset = 0;
 699         int ix;
 700         unsigned hash = name_hash(name);
 701
 702         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 703         if (ix >= 0) {
 704                 if (exclude) {
 705                         entry = objects + object_ix[ix] - 1;
 706                         if (!entry->preferred_base)
 707                                 nr_result--;
 708                         entry->preferred_base = 1;
 709                 }
 710                 return 0;
 711         }
 712
 713         if (!exclude && local && has_loose_object_nonlocal(sha1))
 714                 return 0;
 715
 716         for (p = packed_git; p; p = p->next) {
 717                 off_t offset = find_pack_entry_one(sha1, p);
 718                 if (offset) {
 719                         if (!found_pack) {
 720                                 found_offset = offset;
 721                                 found_pack = p;
 722                         }
 723                         if (exclude)
 724                                 break;
 725                         if (incremental)
 726                                 return 0;
 727                         if (local && !p->pack_local)
 728                                 return 0;
 729                         if (ignore_packed_keep && p->pack_local && p->pack_keep)
 730                                 return 0;
 731                 }
 732         }
 733
 734         if (nr_objects >= nr_alloc) {
 735                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 736                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 737         }
 738
 739         entry = objects + nr_objects++;
 740         memset(entry, 0, sizeof(*entry));
 741         hashcpy(entry->idx.sha1, sha1);
 742         entry->hash = hash;
 743         if (type)
 744                 entry->type = type;
 745         if (exclude)
 746                 entry->preferred_base = 1;
 747         else
 748                 nr_result++;
 749         if (found_pack) {
 750                 entry->in_pack = found_pack;
 751                 entry->in_pack_offset = found_offset;
 752         }
 753
 754         if (object_ix_hashsz * 3 <= nr_objects * 4)
 755                 rehash_objects();
 756         else
 757                 object_ix[-1 - ix] = nr_objects;
 758
 759         display_progress(progress_state, nr_objects);
 760
 761         if (name && no_try_delta(name))
 762                 entry->no_try_delta = 1;
 763
 764         return 1;
 765 }
 766
 767 struct pbase_tree_cache {
 768         unsigned char sha1[20];
 769         int ref;
 770         int temporary;
 771         void *tree_data;
 772         unsigned long tree_size;
 773 };
 774
 775 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 776 static int pbase_tree_cache_ix(const unsigned char *sha1)
 777 {
 778         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 779 }
 780 static int pbase_tree_cache_ix_incr(int ix)
 781 {
 782         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 783 }
 784
 785 static struct pbase_tree {
 786         struct pbase_tree *next;
 787         /* This is a phony "cache" entry; we are not
 788          * going to evict it nor find it through _get()
 789          * mechanism -- this is for the toplevel node that
 790          * would almost always change with any commit.
 791          */
 792         struct pbase_tree_cache pcache;
 793 } *pbase_tree;
 794
 795 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 796 {
 797         struct pbase_tree_cache *ent, *nent;
 798         void *data;
 799         unsigned long size;
 800         enum object_type type;
 801         int neigh;
 802         int my_ix = pbase_tree_cache_ix(sha1);
 803         int available_ix = -1;
 804
 805         /* pbase-tree-cache acts as a limited hashtable.
 806          * your object will be found at your index or within a few
 807          * slots after that slot if it is cached.
 808          */
 809         for (neigh = 0; neigh < 8; neigh++) {
 810                 ent = pbase_tree_cache[my_ix];
 811                 if (ent && !hashcmp(ent->sha1, sha1)) {
 812                         ent->ref++;
 813                         return ent;
 814                 }
 815                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 816                          ((0 <= available_ix) &&
 817                           (!ent && pbase_tree_cache[available_ix])))
 818                         available_ix = my_ix;
 819                 if (!ent)
 820                         break;
 821                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 822         }
 823
 824         /* Did not find one.  Either we got a bogus request or
 825          * we need to read and perhaps cache.
 826          */
 827         data = read_sha1_file(sha1, &type, &size);
 828         if (!data)
 829                 return NULL;
 830         if (type != OBJ_TREE) {
 831                 free(data);
 832                 return NULL;
 833         }
 834
 835         /* We need to either cache or return a throwaway copy */
 836
 837         if (available_ix < 0)
 838                 ent = NULL;
 839         else {
 840                 ent = pbase_tree_cache[available_ix];
 841                 my_ix = available_ix;
 842         }
 843
 844         if (!ent) {
 845                 nent = xmalloc(sizeof(*nent));
 846                 nent->temporary = (available_ix < 0);
 847         }
 848         else {
 849                 /* evict and reuse */
 850                 free(ent->tree_data);
 851                 nent = ent;
 852         }
 853         hashcpy(nent->sha1, sha1);
 854         nent->tree_data = data;
 855         nent->tree_size = size;
 856         nent->ref = 1;
 857         if (!nent->temporary)
 858                 pbase_tree_cache[my_ix] = nent;
 859         return nent;
 860 }
 861
 862 static void pbase_tree_put(struct pbase_tree_cache *cache)
 863 {
 864         if (!cache->temporary) {
 865                 cache->ref--;
 866                 return;
 867         }
 868         free(cache->tree_data);
 869         free(cache);
 870 }
 871
 872 static int name_cmp_len(const char *name)
 873 {
 874         int i;
 875         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 876                 ;
 877         return i;
 878 }
 879
 880 static void add_pbase_object(struct tree_desc *tree,
 881                              const char *name,
 882                              int cmplen,
 883                              const char *fullname)
 884 {
 885         struct name_entry entry;
 886         int cmp;
 887
 888         while (tree_entry(tree,&entry)) {
 889                 if (S_ISGITLINK(entry.mode))
 890                         continue;
 891                 cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
 892                       memcmp(name, entry.path, cmplen);
 893                 if (cmp > 0)
 894                         continue;
 895                 if (cmp < 0)
 896                         return;
 897                 if (name[cmplen] != '/') {
 898                         add_object_entry(entry.sha1,
 899                                          object_type(entry.mode),
 900                                          fullname, 1);
 901                         return;
 902                 }
 903                 if (S_ISDIR(entry.mode)) {
 904                         struct tree_desc sub;
 905                         struct pbase_tree_cache *tree;
 906                         const char *down = name+cmplen+1;
 907                         int downlen = name_cmp_len(down);
 908
 909                         tree = pbase_tree_get(entry.sha1);
 910                         if (!tree)
 911                                 return;
 912                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
 913
 914                         add_pbase_object(&sub, down, downlen, fullname);
 915                         pbase_tree_put(tree);
 916                 }
 917         }
 918 }
 919
 920 static unsigned *done_pbase_paths;
 921 static int done_pbase_paths_num;
 922 static int done_pbase_paths_alloc;
 923 static int done_pbase_path_pos(unsigned hash)
 924 {
 925         int lo = 0;
 926         int hi = done_pbase_paths_num;
 927         while (lo < hi) {
 928                 int mi = (hi + lo) / 2;
 929                 if (done_pbase_paths[mi] == hash)
 930                         return mi;
 931                 if (done_pbase_paths[mi] < hash)
 932                         hi = mi;
 933                 else
 934                         lo = mi + 1;
 935         }
 936         return -lo-1;
 937 }
 938
 939 static int check_pbase_path(unsigned hash)
 940 {
 941         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 942         if (0 <= pos)
 943                 return 1;
 944         pos = -pos - 1;
 945         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 946                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 947                 done_pbase_paths = xrealloc(done_pbase_paths,
 948                                             done_pbase_paths_alloc *
 949                                             sizeof(unsigned));
 950         }
 951         done_pbase_paths_num++;
 952         if (pos < done_pbase_paths_num)
 953                 memmove(done_pbase_paths + pos + 1,
 954                         done_pbase_paths + pos,
 955                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 956         done_pbase_paths[pos] = hash;
 957         return 0;
 958 }
 959
 960 static void add_preferred_base_object(const char *name)
 961 {
 962         struct pbase_tree *it;
 963         int cmplen;
 964         unsigned hash = name_hash(name);
 965
 966         if (!num_preferred_base || check_pbase_path(hash))
 967                 return;
 968
 969         cmplen = name_cmp_len(name);
 970         for (it = pbase_tree; it; it = it->next) {
 971                 if (cmplen == 0) {
 972                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
 973                 }
 974                 else {
 975                         struct tree_desc tree;
 976                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
 977                         add_pbase_object(&tree, name, cmplen, name);
 978                 }
 979         }
 980 }
 981
 982 static void add_preferred_base(unsigned char *sha1)
 983 {
 984         struct pbase_tree *it;
 985         void *data;
 986         unsigned long size;
 987         unsigned char tree_sha1[20];
 988
 989         if (window <= num_preferred_base++)
 990                 return;
 991
 992         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 993         if (!data)
 994                 return;
 995
 996         for (it = pbase_tree; it; it = it->next) {
 997                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
 998                         free(data);
 999                         return;
1000                 }
1001         }
1002
1003         it = xcalloc(1, sizeof(*it));
1004         it->next = pbase_tree;
1005         pbase_tree = it;
1006
1007         hashcpy(it->pcache.sha1, tree_sha1);
1008         it->pcache.tree_data = data;
1009         it->pcache.tree_size = size;
1010 }
1011
1012 static void cleanup_preferred_base(void)
1013 {
1014         struct pbase_tree *it;
1015         unsigned i;
1016
1017         it = pbase_tree;
1018         pbase_tree = NULL;
1019         while (it) {
1020                 struct pbase_tree *this = it;
1021                 it = this->next;
1022                 free(this->pcache.tree_data);
1023                 free(this);
1024         }
1025
1026         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1027                 if (!pbase_tree_cache[i])
1028                         continue;
1029                 free(pbase_tree_cache[i]->tree_data);
1030                 free(pbase_tree_cache[i]);
1031                 pbase_tree_cache[i] = NULL;
1032         }
1033
1034         free(done_pbase_paths);
1035         done_pbase_paths = NULL;
1036         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1037 }
1038
1039 static void check_object(struct object_entry *entry)
1040 {
1041         if (entry->in_pack) {
1042                 struct packed_git *p = entry->in_pack;
1043                 struct pack_window *w_curs = NULL;
1044                 const unsigned char *base_ref = NULL;
1045                 struct object_entry *base_entry;
1046                 unsigned long used, used_0;
1047                 unsigned int avail;
1048                 off_t ofs;
1049                 unsigned char *buf, c;
1050
1051                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1052
1053                 /*
1054                  * We want in_pack_type even if we do not reuse delta
1055                  * since non-delta representations could still be reused.
1056                  */
1057                 used = unpack_object_header_buffer(buf, avail,
1058                                                    &entry->in_pack_type,
1059                                                    &entry->size);
1060                 if (used == 0)
1061                         goto give_up;
1062
1063                 /*
1064                  * Determine if this is a delta and if so whether we can
1065                  * reuse it or not.  Otherwise let's find out as cheaply as
1066                  * possible what the actual type and size for this object is.
1067                  */
1068                 switch (entry->in_pack_type) {
1069                 default:
1070                         /* Not a delta hence we've already got all we need. */
1071                         entry->type = entry->in_pack_type;
1072                         entry->in_pack_header_size = used;
1073                         if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1074                                 goto give_up;
1075                         unuse_pack(&w_curs);
1076                         return;
1077                 case OBJ_REF_DELTA:
1078                         if (reuse_delta && !entry->preferred_base)
1079                                 base_ref = use_pack(p, &w_curs,
1080                                                 entry->in_pack_offset + used, NULL);
1081                         entry->in_pack_header_size = used + 20;
1082                         break;
1083                 case OBJ_OFS_DELTA:
1084                         buf = use_pack(p, &w_curs,
1085                                        entry->in_pack_offset + used, NULL);
1086                         used_0 = 0;
1087                         c = buf[used_0++];
1088                         ofs = c & 127;
1089                         while (c & 128) {
1090                                 ofs += 1;
1091                                 if (!ofs || MSB(ofs, 7)) {
1092                                         error("delta base offset overflow in pack for %s",
1093                                               sha1_to_hex(entry->idx.sha1));
1094                                         goto give_up;
1095                                 }
1096                                 c = buf[used_0++];
1097                                 ofs = (ofs << 7) + (c & 127);
1098                         }
1099                         ofs = entry->in_pack_offset - ofs;
1100                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1101                                 error("delta base offset out of bound for %s",
1102                                       sha1_to_hex(entry->idx.sha1));
1103                                 goto give_up;
1104                         }
1105                         if (reuse_delta && !entry->preferred_base) {
1106                                 struct revindex_entry *revidx;
1107                                 revidx = find_pack_revindex(p, ofs);
1108                                 if (!revidx)
1109                                         goto give_up;
1110                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1111                         }
1112                         entry->in_pack_header_size = used + used_0;
1113                         break;
1114                 }
1115
1116                 if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1117                         /*
1118                          * If base_ref was set above that means we wish to
1119                          * reuse delta data, and we even found that base
1120                          * in the list of objects we want to pack. Goodie!
1121                          *
1122                          * Depth value does not matter - find_deltas() will
1123                          * never consider reused delta as the base object to
1124                          * deltify other objects against, in order to avoid
1125                          * circular deltas.
1126                          */
1127                         entry->type = entry->in_pack_type;
1128                         entry->delta = base_entry;
1129                         entry->delta_size = entry->size;
1130                         entry->delta_sibling = base_entry->delta_child;
1131                         base_entry->delta_child = entry;
1132                         unuse_pack(&w_curs);
1133                         return;
1134                 }
1135
1136                 if (entry->type) {
1137                         /*
1138                          * This must be a delta and we already know what the
1139                          * final object type is.  Let's extract the actual
1140                          * object size from the delta header.
1141                          */
1142                         entry->size = get_size_from_delta(p, &w_curs,
1143                                         entry->in_pack_offset + entry->in_pack_header_size);
1144                         if (entry->size == 0)
1145                                 goto give_up;
1146                         unuse_pack(&w_curs);
1147                         return;
1148                 }
1149
1150                 /*
1151                  * No choice but to fall back to the recursive delta walk
1152                  * with sha1_object_info() to find about the object type
1153                  * at this point...
1154                  */
1155                 give_up:
1156                 unuse_pack(&w_curs);
1157         }
1158
1159         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1160         /*
1161          * The error condition is checked in prepare_pack().  This is
1162          * to permit a missing preferred base object to be ignored
1163          * as a preferred base.  Doing so can result in a larger
1164          * pack file, but the transfer will still take place.
1165          */
1166 }
1167
1168 static int pack_offset_sort(const void *_a, const void *_b)
1169 {
1170         const struct object_entry *a = *(struct object_entry **)_a;
1171         const struct object_entry *b = *(struct object_entry **)_b;
1172
1173         /* avoid filesystem trashing with loose objects */
1174         if (!a->in_pack && !b->in_pack)
1175                 return hashcmp(a->idx.sha1, b->idx.sha1);
1176
1177         if (a->in_pack < b->in_pack)
1178                 return -1;
1179         if (a->in_pack > b->in_pack)
1180                 return 1;
1181         return a->in_pack_offset < b->in_pack_offset ? -1 :
1182                         (a->in_pack_offset > b->in_pack_offset);
1183 }
1184
1185 static void get_object_details(void)
1186 {
1187         uint32_t i;
1188         struct object_entry **sorted_by_offset;
1189
1190         sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1191         for (i = 0; i < nr_objects; i++)
1192                 sorted_by_offset[i] = objects + i;
1193         qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1194
1195         for (i = 0; i < nr_objects; i++)
1196                 check_object(sorted_by_offset[i]);
1197
1198         free(sorted_by_offset);
1199 }
1200
1201 /*
1202  * We search for deltas in a list sorted by type, by filename hash, and then
1203  * by size, so that we see progressively smaller and smaller files.
1204  * That's because we prefer deltas to be from the bigger file
1205  * to the smaller -- deletes are potentially cheaper, but perhaps
1206  * more importantly, the bigger file is likely the more recent
1207  * one.  The deepest deltas are therefore the oldest objects which are
1208  * less susceptible to be accessed often.
1209  */
1210 static int type_size_sort(const void *_a, const void *_b)
1211 {
1212         const struct object_entry *a = *(struct object_entry **)_a;
1213         const struct object_entry *b = *(struct object_entry **)_b;
1214
1215         if (a->type > b->type)
1216                 return -1;
1217         if (a->type < b->type)
1218                 return 1;
1219         if (a->hash > b->hash)
1220                 return -1;
1221         if (a->hash < b->hash)
1222                 return 1;
1223         if (a->preferred_base > b->preferred_base)
1224                 return -1;
1225         if (a->preferred_base < b->preferred_base)
1226                 return 1;
1227         if (a->size > b->size)
1228                 return -1;
1229         if (a->size < b->size)
1230                 return 1;
1231         return a < b ? -1 : (a > b);  /* newest first */
1232 }
1233
1234 struct unpacked {
1235         struct object_entry *entry;
1236         void *data;
1237         struct delta_index *index;
1238         unsigned depth;
1239 };
1240
1241 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1242                            unsigned long delta_size)
1243 {
1244         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1245                 return 0;
1246
1247         if (delta_size < cache_max_small_delta_size)
1248                 return 1;
1249
1250         /* cache delta, if objects are large enough compared to delta size */
1251         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1252                 return 1;
1253
1254         return 0;
1255 }
1256
1257 #ifdef THREADED_DELTA_SEARCH
1258
1259 static pthread_mutex_t read_mutex = PTHREAD_MUTEX_INITIALIZER;
1260 #define read_lock()             pthread_mutex_lock(&read_mutex)
1261 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1262
1263 static pthread_mutex_t cache_mutex = PTHREAD_MUTEX_INITIALIZER;
1264 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1265 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1266
1267 static pthread_mutex_t progress_mutex = PTHREAD_MUTEX_INITIALIZER;
1268 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1269 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1270
1271 #else
1272
1273 #define read_lock()             (void)0
1274 #define read_unlock()           (void)0
1275 #define cache_lock()            (void)0
1276 #define cache_unlock()          (void)0
1277 #define progress_lock()         (void)0
1278 #define progress_unlock()       (void)0
1279
1280 #endif
1281
1282 static int try_delta(struct unpacked *trg, struct unpacked *src,
1283                      unsigned max_depth, unsigned long *mem_usage)
1284 {
1285         struct object_entry *trg_entry = trg->entry;
1286         struct object_entry *src_entry = src->entry;
1287         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1288         unsigned ref_depth;
1289         enum object_type type;
1290         void *delta_buf;
1291
1292         /* Don't bother doing diffs between different types */
1293         if (trg_entry->type != src_entry->type)
1294                 return -1;
1295
1296         /*
1297          * We do not bother to try a delta that we discarded
1298          * on an earlier try, but only when reusing delta data.
1299          */
1300         if (reuse_delta && trg_entry->in_pack &&
1301             trg_entry->in_pack == src_entry->in_pack &&
1302             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1303             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1304                 return 0;
1305
1306         /* Let's not bust the allowed depth. */
1307         if (src->depth >= max_depth)
1308                 return 0;
1309
1310         /* Now some size filtering heuristics. */
1311         trg_size = trg_entry->size;
1312         if (!trg_entry->delta) {
1313                 max_size = trg_size/2 - 20;
1314                 ref_depth = 1;
1315         } else {
1316                 max_size = trg_entry->delta_size;
1317                 ref_depth = trg->depth;
1318         }
1319         max_size = (uint64_t)max_size * (max_depth - src->depth) /
1320                                                 (max_depth - ref_depth + 1);
1321         if (max_size == 0)
1322                 return 0;
1323         src_size = src_entry->size;
1324         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1325         if (sizediff >= max_size)
1326                 return 0;
1327         if (trg_size < src_size / 32)
1328                 return 0;
1329
1330         /* Load data if not already done */
1331         if (!trg->data) {
1332                 read_lock();
1333                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1334                 read_unlock();
1335                 if (!trg->data)
1336                         die("object %s cannot be read",
1337                             sha1_to_hex(trg_entry->idx.sha1));
1338                 if (sz != trg_size)
1339                         die("object %s inconsistent object length (%lu vs %lu)",
1340                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1341                 *mem_usage += sz;
1342         }
1343         if (!src->data) {
1344                 read_lock();
1345                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1346                 read_unlock();
1347                 if (!src->data)
1348                         die("object %s cannot be read",
1349                             sha1_to_hex(src_entry->idx.sha1));
1350                 if (sz != src_size)
1351                         die("object %s inconsistent object length (%lu vs %lu)",
1352                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1353                 *mem_usage += sz;
1354         }
1355         if (!src->index) {
1356                 src->index = create_delta_index(src->data, src_size);
1357                 if (!src->index) {
1358                         static int warned = 0;
1359                         if (!warned++)
1360                                 warning("suboptimal pack - out of memory");
1361                         return 0;
1362                 }
1363                 *mem_usage += sizeof_delta_index(src->index);
1364         }
1365
1366         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1367         if (!delta_buf)
1368                 return 0;
1369
1370         if (trg_entry->delta) {
1371                 /* Prefer only shallower same-sized deltas. */
1372                 if (delta_size == trg_entry->delta_size &&
1373                     src->depth + 1 >= trg->depth) {
1374                         free(delta_buf);
1375                         return 0;
1376                 }
1377         }
1378
1379         /*
1380          * Handle memory allocation outside of the cache
1381          * accounting lock.  Compiler will optimize the strangeness
1382          * away when THREADED_DELTA_SEARCH is not defined.
1383          */
1384         free(trg_entry->delta_data);
1385         cache_lock();
1386         if (trg_entry->delta_data) {
1387                 delta_cache_size -= trg_entry->delta_size;
1388                 trg_entry->delta_data = NULL;
1389         }
1390         if (delta_cacheable(src_size, trg_size, delta_size)) {
1391                 delta_cache_size += delta_size;
1392                 cache_unlock();
1393                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1394         } else {
1395                 cache_unlock();
1396                 free(delta_buf);
1397         }
1398
1399         trg_entry->delta = src_entry;
1400         trg_entry->delta_size = delta_size;
1401         trg->depth = src->depth + 1;
1402
1403         return 1;
1404 }
1405
1406 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1407 {
1408         struct object_entry *child = me->delta_child;
1409         unsigned int m = n;
1410         while (child) {
1411                 unsigned int c = check_delta_limit(child, n + 1);
1412                 if (m < c)
1413                         m = c;
1414                 child = child->delta_sibling;
1415         }
1416         return m;
1417 }
1418
1419 static unsigned long free_unpacked(struct unpacked *n)
1420 {
1421         unsigned long freed_mem = sizeof_delta_index(n->index);
1422         free_delta_index(n->index);
1423         n->index = NULL;
1424         if (n->data) {
1425                 freed_mem += n->entry->size;
1426                 free(n->data);
1427                 n->data = NULL;
1428         }
1429         n->entry = NULL;
1430         n->depth = 0;
1431         return freed_mem;
1432 }
1433
1434 static void find_deltas(struct object_entry **list, unsigned *list_size,
1435                         int window, int depth, unsigned *processed)
1436 {
1437         uint32_t i, idx = 0, count = 0;
1438         struct unpacked *array;
1439         unsigned long mem_usage = 0;
1440
1441         array = xcalloc(window, sizeof(struct unpacked));
1442
1443         for (;;) {
1444                 struct object_entry *entry;
1445                 struct unpacked *n = array + idx;
1446                 int j, max_depth, best_base = -1;
1447
1448                 progress_lock();
1449                 if (!*list_size) {
1450                         progress_unlock();
1451                         break;
1452                 }
1453                 entry = *list++;
1454                 (*list_size)--;
1455                 if (!entry->preferred_base) {
1456                         (*processed)++;
1457                         display_progress(progress_state, *processed);
1458                 }
1459                 progress_unlock();
1460
1461                 mem_usage -= free_unpacked(n);
1462                 n->entry = entry;
1463
1464                 while (window_memory_limit &&
1465                        mem_usage > window_memory_limit &&
1466                        count > 1) {
1467                         uint32_t tail = (idx + window - count) % window;
1468                         mem_usage -= free_unpacked(array + tail);
1469                         count--;
1470                 }
1471
1472                 /* We do not compute delta to *create* objects we are not
1473                  * going to pack.
1474                  */
1475                 if (entry->preferred_base)
1476                         goto next;
1477
1478                 /*
1479                  * If the current object is at pack edge, take the depth the
1480                  * objects that depend on the current object into account
1481                  * otherwise they would become too deep.
1482                  */
1483                 max_depth = depth;
1484                 if (entry->delta_child) {
1485                         max_depth -= check_delta_limit(entry, 0);
1486                         if (max_depth <= 0)
1487                                 goto next;
1488                 }
1489
1490                 j = window;
1491                 while (--j > 0) {
1492                         int ret;
1493                         uint32_t other_idx = idx + j;
1494                         struct unpacked *m;
1495                         if (other_idx >= window)
1496                                 other_idx -= window;
1497                         m = array + other_idx;
1498                         if (!m->entry)
1499                                 break;
1500                         ret = try_delta(n, m, max_depth, &mem_usage);
1501                         if (ret < 0)
1502                                 break;
1503                         else if (ret > 0)
1504                                 best_base = other_idx;
1505                 }
1506
1507                 /*
1508                  * If we decided to cache the delta data, then it is best
1509                  * to compress it right away.  First because we have to do
1510                  * it anyway, and doing it here while we're threaded will
1511                  * save a lot of time in the non threaded write phase,
1512                  * as well as allow for caching more deltas within
1513                  * the same cache size limit.
1514                  * ...
1515                  * But only if not writing to stdout, since in that case
1516                  * the network is most likely throttling writes anyway,
1517                  * and therefore it is best to go to the write phase ASAP
1518                  * instead, as we can afford spending more time compressing
1519                  * between writes at that moment.
1520                  */
1521                 if (entry->delta_data && !pack_to_stdout) {
1522                         entry->z_delta_size = do_compress(&entry->delta_data,
1523                                                           entry->delta_size);
1524                         cache_lock();
1525                         delta_cache_size -= entry->delta_size;
1526                         delta_cache_size += entry->z_delta_size;
1527                         cache_unlock();
1528                 }
1529
1530                 /* if we made n a delta, and if n is already at max
1531                  * depth, leaving it in the window is pointless.  we
1532                  * should evict it first.
1533                  */
1534                 if (entry->delta && max_depth <= n->depth)
1535                         continue;
1536
1537                 /*
1538                  * Move the best delta base up in the window, after the
1539                  * currently deltified object, to keep it longer.  It will
1540                  * be the first base object to be attempted next.
1541                  */
1542                 if (entry->delta) {
1543                         struct unpacked swap = array[best_base];
1544                         int dist = (window + idx - best_base) % window;
1545                         int dst = best_base;
1546                         while (dist--) {
1547                                 int src = (dst + 1) % window;
1548                                 array[dst] = array[src];
1549                                 dst = src;
1550                         }
1551                         array[dst] = swap;
1552                 }
1553
1554                 next:
1555                 idx++;
1556                 if (count + 1 < window)
1557                         count++;
1558                 if (idx >= window)
1559                         idx = 0;
1560         }
1561
1562         for (i = 0; i < window; ++i) {
1563                 free_delta_index(array[i].index);
1564                 free(array[i].data);
1565         }
1566         free(array);
1567 }
1568
1569 #ifdef THREADED_DELTA_SEARCH
1570
1571 /*
1572  * The main thread waits on the condition that (at least) one of the workers
1573  * has stopped working (which is indicated in the .working member of
1574  * struct thread_params).
1575  * When a work thread has completed its work, it sets .working to 0 and
1576  * signals the main thread and waits on the condition that .data_ready
1577  * becomes 1.
1578  */
1579
1580 struct thread_params {
1581         pthread_t thread;
1582         struct object_entry **list;
1583         unsigned list_size;
1584         unsigned remaining;
1585         int window;
1586         int depth;
1587         int working;
1588         int data_ready;
1589         pthread_mutex_t mutex;
1590         pthread_cond_t cond;
1591         unsigned *processed;
1592 };
1593
1594 static pthread_cond_t progress_cond = PTHREAD_COND_INITIALIZER;
1595
1596 static void *threaded_find_deltas(void *arg)
1597 {
1598         struct thread_params *me = arg;
1599
1600         while (me->remaining) {
1601                 find_deltas(me->list, &me->remaining,
1602                             me->window, me->depth, me->processed);
1603
1604                 progress_lock();
1605                 me->working = 0;
1606                 pthread_cond_signal(&progress_cond);
1607                 progress_unlock();
1608
1609                 /*
1610                  * We must not set ->data_ready before we wait on the
1611                  * condition because the main thread may have set it to 1
1612                  * before we get here. In order to be sure that new
1613                  * work is available if we see 1 in ->data_ready, it
1614                  * was initialized to 0 before this thread was spawned
1615                  * and we reset it to 0 right away.
1616                  */
1617                 pthread_mutex_lock(&me->mutex);
1618                 while (!me->data_ready)
1619                         pthread_cond_wait(&me->cond, &me->mutex);
1620                 me->data_ready = 0;
1621                 pthread_mutex_unlock(&me->mutex);
1622         }
1623         /* leave ->working 1 so that this doesn't get more work assigned */
1624         return NULL;
1625 }
1626
1627 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1628                            int window, int depth, unsigned *processed)
1629 {
1630         struct thread_params *p;
1631         int i, ret, active_threads = 0;
1632
1633         if (!delta_search_threads)      /* --threads=0 means autodetect */
1634                 delta_search_threads = online_cpus();
1635         if (delta_search_threads <= 1) {
1636                 find_deltas(list, &list_size, window, depth, processed);
1637                 return;
1638         }
1639         if (progress > pack_to_stdout)
1640                 fprintf(stderr, "Delta compression using up to %d threads.\n",
1641                                 delta_search_threads);
1642         p = xcalloc(delta_search_threads, sizeof(*p));
1643
1644         /* Partition the work amongst work threads. */
1645         for (i = 0; i < delta_search_threads; i++) {
1646                 unsigned sub_size = list_size / (delta_search_threads - i);
1647
1648                 /* don't use too small segments or no deltas will be found */
1649                 if (sub_size < 2*window && i+1 < delta_search_threads)
1650                         sub_size = 0;
1651
1652                 p[i].window = window;
1653                 p[i].depth = depth;
1654                 p[i].processed = processed;
1655                 p[i].working = 1;
1656                 p[i].data_ready = 0;
1657
1658                 /* try to split chunks on "path" boundaries */
1659                 while (sub_size && sub_size < list_size &&
1660                        list[sub_size]->hash &&
1661                        list[sub_size]->hash == list[sub_size-1]->hash)
1662                         sub_size++;
1663
1664                 p[i].list = list;
1665                 p[i].list_size = sub_size;
1666                 p[i].remaining = sub_size;
1667
1668                 list += sub_size;
1669                 list_size -= sub_size;
1670         }
1671
1672         /* Start work threads. */
1673         for (i = 0; i < delta_search_threads; i++) {
1674                 if (!p[i].list_size)
1675                         continue;
1676                 pthread_mutex_init(&p[i].mutex, NULL);
1677                 pthread_cond_init(&p[i].cond, NULL);
1678                 ret = pthread_create(&p[i].thread, NULL,
1679                                      threaded_find_deltas, &p[i]);
1680                 if (ret)
1681                         die("unable to create thread: %s", strerror(ret));
1682                 active_threads++;
1683         }
1684
1685         /*
1686          * Now let's wait for work completion.  Each time a thread is done
1687          * with its work, we steal half of the remaining work from the
1688          * thread with the largest number of unprocessed objects and give
1689          * it to that newly idle thread.  This ensure good load balancing
1690          * until the remaining object list segments are simply too short
1691          * to be worth splitting anymore.
1692          */
1693         while (active_threads) {
1694                 struct thread_params *target = NULL;
1695                 struct thread_params *victim = NULL;
1696                 unsigned sub_size = 0;
1697
1698                 progress_lock();
1699                 for (;;) {
1700                         for (i = 0; !target && i < delta_search_threads; i++)
1701                                 if (!p[i].working)
1702                                         target = &p[i];
1703                         if (target)
1704                                 break;
1705                         pthread_cond_wait(&progress_cond, &progress_mutex);
1706                 }
1707
1708                 for (i = 0; i < delta_search_threads; i++)
1709                         if (p[i].remaining > 2*window &&
1710                             (!victim || victim->remaining < p[i].remaining))
1711                                 victim = &p[i];
1712                 if (victim) {
1713                         sub_size = victim->remaining / 2;
1714                         list = victim->list + victim->list_size - sub_size;
1715                         while (sub_size && list[0]->hash &&
1716                                list[0]->hash == list[-1]->hash) {
1717                                 list++;
1718                                 sub_size--;
1719                         }
1720                         if (!sub_size) {
1721                                 /*
1722                                  * It is possible for some "paths" to have
1723                                  * so many objects that no hash boundary
1724                                  * might be found.  Let's just steal the
1725                                  * exact half in that case.
1726                                  */
1727                                 sub_size = victim->remaining / 2;
1728                                 list -= sub_size;
1729                         }
1730                         target->list = list;
1731                         victim->list_size -= sub_size;
1732                         victim->remaining -= sub_size;
1733                 }
1734                 target->list_size = sub_size;
1735                 target->remaining = sub_size;
1736                 target->working = 1;
1737                 progress_unlock();
1738
1739                 pthread_mutex_lock(&target->mutex);
1740                 target->data_ready = 1;
1741                 pthread_cond_signal(&target->cond);
1742                 pthread_mutex_unlock(&target->mutex);
1743
1744                 if (!sub_size) {
1745                         pthread_join(target->thread, NULL);
1746                         pthread_cond_destroy(&target->cond);
1747                         pthread_mutex_destroy(&target->mutex);
1748                         active_threads--;
1749                 }
1750         }
1751         free(p);
1752 }
1753
1754 #else
1755 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
1756 #endif
1757
1758 static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1759 {
1760         unsigned char peeled[20];
1761
1762         if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
1763             !peel_ref(path, peeled)        && /* peelable? */
1764             !is_null_sha1(peeled)          && /* annotated tag? */
1765             locate_object_entry(peeled))      /* object packed? */
1766                 add_object_entry(sha1, OBJ_TAG, NULL, 0);
1767         return 0;
1768 }
1769
1770 static void prepare_pack(int window, int depth)
1771 {
1772         struct object_entry **delta_list;
1773         uint32_t i, nr_deltas;
1774         unsigned n;
1775
1776         get_object_details();
1777
1778         /*
1779          * If we're locally repacking then we need to be doubly careful
1780          * from now on in order to make sure no stealth corruption gets
1781          * propagated to the new pack.  Clients receiving streamed packs
1782          * should validate everything they get anyway so no need to incur
1783          * the additional cost here in that case.
1784          */
1785         if (!pack_to_stdout)
1786                 do_check_packed_object_crc = 1;
1787
1788         if (!nr_objects || !window || !depth)
1789                 return;
1790
1791         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1792         nr_deltas = n = 0;
1793
1794         for (i = 0; i < nr_objects; i++) {
1795                 struct object_entry *entry = objects + i;
1796
1797                 if (entry->delta)
1798                         /* This happens if we decided to reuse existing
1799                          * delta from a pack.  "reuse_delta &&" is implied.
1800                          */
1801                         continue;
1802
1803                 if (entry->size < 50)
1804                         continue;
1805
1806                 if (entry->no_try_delta)
1807                         continue;
1808
1809                 if (!entry->preferred_base) {
1810                         nr_deltas++;
1811                         if (entry->type < 0)
1812                                 die("unable to get type of object %s",
1813                                     sha1_to_hex(entry->idx.sha1));
1814                 } else {
1815                         if (entry->type < 0) {
1816                                 /*
1817                                  * This object is not found, but we
1818                                  * don't have to include it anyway.
1819                                  */
1820                                 continue;
1821                         }
1822                 }
1823
1824                 delta_list[n++] = entry;
1825         }
1826
1827         if (nr_deltas && n > 1) {
1828                 unsigned nr_done = 0;
1829                 if (progress)
1830                         progress_state = start_progress("Compressing objects",
1831                                                         nr_deltas);
1832                 qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
1833                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
1834                 stop_progress(&progress_state);
1835                 if (nr_done != nr_deltas)
1836                         die("inconsistency with delta count");
1837         }
1838         free(delta_list);
1839 }
1840
1841 static int git_pack_config(const char *k, const char *v, void *cb)
1842 {
1843         if (!strcmp(k, "pack.window")) {
1844                 window = git_config_int(k, v);
1845                 return 0;
1846         }
1847         if (!strcmp(k, "pack.windowmemory")) {
1848                 window_memory_limit = git_config_ulong(k, v);
1849                 return 0;
1850         }
1851         if (!strcmp(k, "pack.depth")) {
1852                 depth = git_config_int(k, v);
1853                 return 0;
1854         }
1855         if (!strcmp(k, "pack.compression")) {
1856                 int level = git_config_int(k, v);
1857                 if (level == -1)
1858                         level = Z_DEFAULT_COMPRESSION;
1859                 else if (level < 0 || level > Z_BEST_COMPRESSION)
1860                         die("bad pack compression level %d", level);
1861                 pack_compression_level = level;
1862                 pack_compression_seen = 1;
1863                 return 0;
1864         }
1865         if (!strcmp(k, "pack.deltacachesize")) {
1866                 max_delta_cache_size = git_config_int(k, v);
1867                 return 0;
1868         }
1869         if (!strcmp(k, "pack.deltacachelimit")) {
1870                 cache_max_small_delta_size = git_config_int(k, v);
1871                 return 0;
1872         }
1873         if (!strcmp(k, "pack.threads")) {
1874                 delta_search_threads = git_config_int(k, v);
1875                 if (delta_search_threads < 0)
1876                         die("invalid number of threads specified (%d)",
1877                             delta_search_threads);
1878 #ifndef THREADED_DELTA_SEARCH
1879                 if (delta_search_threads != 1)
1880                         warning("no threads support, ignoring %s", k);
1881 #endif
1882                 return 0;
1883         }
1884         if (!strcmp(k, "pack.indexversion")) {
1885                 pack_idx_default_version = git_config_int(k, v);
1886                 if (pack_idx_default_version > 2)
1887                         die("bad pack.indexversion=%"PRIu32,
1888                                 pack_idx_default_version);
1889                 return 0;
1890         }
1891         if (!strcmp(k, "pack.packsizelimit")) {
1892                 pack_size_limit_cfg = git_config_ulong(k, v);
1893                 return 0;
1894         }
1895         return git_default_config(k, v, cb);
1896 }
1897
1898 static void read_object_list_from_stdin(void)
1899 {
1900         char line[40 + 1 + PATH_MAX + 2];
1901         unsigned char sha1[20];
1902
1903         for (;;) {
1904                 if (!fgets(line, sizeof(line), stdin)) {
1905                         if (feof(stdin))
1906                                 break;
1907                         if (!ferror(stdin))
1908                                 die("fgets returned NULL, not EOF, not error!");
1909                         if (errno != EINTR)
1910                                 die_errno("fgets");
1911                         clearerr(stdin);
1912                         continue;
1913                 }
1914                 if (line[0] == '-') {
1915                         if (get_sha1_hex(line+1, sha1))
1916                                 die("expected edge sha1, got garbage:\n %s",
1917                                     line);
1918                         add_preferred_base(sha1);
1919                         continue;
1920                 }
1921                 if (get_sha1_hex(line, sha1))
1922                         die("expected sha1, got garbage:\n %s", line);
1923
1924                 add_preferred_base_object(line+41);
1925                 add_object_entry(sha1, 0, line+41, 0);
1926         }
1927 }
1928
1929 #define OBJECT_ADDED (1u<<20)
1930
1931 static void show_commit(struct commit *commit, void *data)
1932 {
1933         add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
1934         commit->object.flags |= OBJECT_ADDED;
1935 }
1936
1937 static void show_object(struct object *obj, const struct name_path *path, const char *last)
1938 {
1939         char *name = path_name(path, last);
1940
1941         add_preferred_base_object(name);
1942         add_object_entry(obj->sha1, obj->type, name, 0);
1943         obj->flags |= OBJECT_ADDED;
1944
1945         /*
1946          * We will have generated the hash from the name,
1947          * but not saved a pointer to it - we can free it
1948          */
1949         free((char *)name);
1950 }
1951
1952 static void show_edge(struct commit *commit)
1953 {
1954         add_preferred_base(commit->object.sha1);
1955 }
1956
1957 struct in_pack_object {
1958         off_t offset;
1959         struct object *object;
1960 };
1961
1962 struct in_pack {
1963         int alloc;
1964         int nr;
1965         struct in_pack_object *array;
1966 };
1967
1968 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
1969 {
1970         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
1971         in_pack->array[in_pack->nr].object = object;
1972         in_pack->nr++;
1973 }
1974
1975 /*
1976  * Compare the objects in the offset order, in order to emulate the
1977  * "git rev-list --objects" output that produced the pack originally.
1978  */
1979 static int ofscmp(const void *a_, const void *b_)
1980 {
1981         struct in_pack_object *a = (struct in_pack_object *)a_;
1982         struct in_pack_object *b = (struct in_pack_object *)b_;
1983
1984         if (a->offset < b->offset)
1985                 return -1;
1986         else if (a->offset > b->offset)
1987                 return 1;
1988         else
1989                 return hashcmp(a->object->sha1, b->object->sha1);
1990 }
1991
1992 static void add_objects_in_unpacked_packs(struct rev_info *revs)
1993 {
1994         struct packed_git *p;
1995         struct in_pack in_pack;
1996         uint32_t i;
1997
1998         memset(&in_pack, 0, sizeof(in_pack));
1999
2000         for (p = packed_git; p; p = p->next) {
2001                 const unsigned char *sha1;
2002                 struct object *o;
2003
2004                 if (!p->pack_local || p->pack_keep)
2005                         continue;
2006                 if (open_pack_index(p))
2007                         die("cannot open pack index");
2008
2009                 ALLOC_GROW(in_pack.array,
2010                            in_pack.nr + p->num_objects,
2011                            in_pack.alloc);
2012
2013                 for (i = 0; i < p->num_objects; i++) {
2014                         sha1 = nth_packed_object_sha1(p, i);
2015                         o = lookup_unknown_object(sha1);
2016                         if (!(o->flags & OBJECT_ADDED))
2017                                 mark_in_pack_object(o, p, &in_pack);
2018                         o->flags |= OBJECT_ADDED;
2019                 }
2020         }
2021
2022         if (in_pack.nr) {
2023                 qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
2024                       ofscmp);
2025                 for (i = 0; i < in_pack.nr; i++) {
2026                         struct object *o = in_pack.array[i].object;
2027                         add_object_entry(o->sha1, o->type, "", 0);
2028                 }
2029         }
2030         free(in_pack.array);
2031 }
2032
2033 static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
2034 {
2035         static struct packed_git *last_found = (void *)1;
2036         struct packed_git *p;
2037
2038         p = (last_found != (void *)1) ? last_found : packed_git;
2039
2040         while (p) {
2041                 if ((!p->pack_local || p->pack_keep) &&
2042                         find_pack_entry_one(sha1, p)) {
2043                         last_found = p;
2044                         return 1;
2045                 }
2046                 if (p == last_found)
2047                         p = packed_git;
2048                 else
2049                         p = p->next;
2050                 if (p == last_found)
2051                         p = p->next;
2052         }
2053         return 0;
2054 }
2055
2056 static void loosen_unused_packed_objects(struct rev_info *revs)
2057 {
2058         struct packed_git *p;
2059         uint32_t i;
2060         const unsigned char *sha1;
2061
2062         for (p = packed_git; p; p = p->next) {
2063                 if (!p->pack_local || p->pack_keep)
2064                         continue;
2065
2066                 if (open_pack_index(p))
2067                         die("cannot open pack index");
2068
2069                 for (i = 0; i < p->num_objects; i++) {
2070                         sha1 = nth_packed_object_sha1(p, i);
2071                         if (!locate_object_entry(sha1) &&
2072                                 !has_sha1_pack_kept_or_nonlocal(sha1))
2073                                 if (force_object_loose(sha1, p->mtime))
2074                                         die("unable to force loose object");
2075                 }
2076         }
2077 }
2078
2079 static void get_object_list(int ac, const char **av)
2080 {
2081         struct rev_info revs;
2082         char line[1000];
2083         int flags = 0;
2084
2085         init_revisions(&revs, NULL);
2086         save_commit_buffer = 0;
2087         setup_revisions(ac, av, &revs, NULL);
2088
2089         while (fgets(line, sizeof(line), stdin) != NULL) {
2090                 int len = strlen(line);
2091                 if (len && line[len - 1] == '\n')
2092                         line[--len] = 0;
2093                 if (!len)
2094                         break;
2095                 if (*line == '-') {
2096                         if (!strcmp(line, "--not")) {
2097                                 flags ^= UNINTERESTING;
2098                                 continue;
2099                         }
2100                         die("not a rev '%s'", line);
2101                 }
2102                 if (handle_revision_arg(line, &revs, flags, 1))
2103                         die("bad revision '%s'", line);
2104         }
2105
2106         if (prepare_revision_walk(&revs))
2107                 die("revision walk setup failed");
2108         mark_edges_uninteresting(revs.commits, &revs, show_edge);
2109         traverse_commit_list(&revs, show_commit, show_object, NULL);
2110
2111         if (keep_unreachable)
2112                 add_objects_in_unpacked_packs(&revs);
2113         if (unpack_unreachable)
2114                 loosen_unused_packed_objects(&revs);
2115 }
2116
2117 static int adjust_perm(const char *path, mode_t mode)
2118 {
2119         if (chmod(path, mode))
2120                 return -1;
2121         return adjust_shared_perm(path);
2122 }
2123
2124 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2125 {
2126         int use_internal_rev_list = 0;
2127         int thin = 0;
2128         int all_progress_implied = 0;
2129         uint32_t i;
2130         const char **rp_av;
2131         int rp_ac_alloc = 64;
2132         int rp_ac;
2133
2134         read_replace_refs = 0;
2135
2136         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
2137
2138         rp_av[0] = "pack-objects";
2139         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
2140         rp_ac = 2;
2141
2142         git_config(git_pack_config, NULL);
2143         if (!pack_compression_seen && core_compression_seen)
2144                 pack_compression_level = core_compression_level;
2145
2146         progress = isatty(2);
2147         for (i = 1; i < argc; i++) {
2148                 const char *arg = argv[i];
2149
2150                 if (*arg != '-')
2151                         break;
2152
2153                 if (!strcmp("--non-empty", arg)) {
2154                         non_empty = 1;
2155                         continue;
2156                 }
2157                 if (!strcmp("--local", arg)) {
2158                         local = 1;
2159                         continue;
2160                 }
2161                 if (!strcmp("--incremental", arg)) {
2162                         incremental = 1;
2163                         continue;
2164                 }
2165                 if (!strcmp("--honor-pack-keep", arg)) {
2166                         ignore_packed_keep = 1;
2167                         continue;
2168                 }
2169                 if (!prefixcmp(arg, "--compression=")) {
2170                         char *end;
2171                         int level = strtoul(arg+14, &end, 0);
2172                         if (!arg[14] || *end)
2173                                 usage(pack_usage);
2174                         if (level == -1)
2175                                 level = Z_DEFAULT_COMPRESSION;
2176                         else if (level < 0 || level > Z_BEST_COMPRESSION)
2177                                 die("bad pack compression level %d", level);
2178                         pack_compression_level = level;
2179                         continue;
2180                 }
2181                 if (!prefixcmp(arg, "--max-pack-size=")) {
2182                         char *end;
2183                         pack_size_limit_cfg = 0;
2184                         pack_size_limit = strtoul(arg+16, &end, 0) * 1024 * 1024;
2185                         if (!arg[16] || *end)
2186                                 usage(pack_usage);
2187                         continue;
2188                 }
2189                 if (!prefixcmp(arg, "--window=")) {
2190                         char *end;
2191                         window = strtoul(arg+9, &end, 0);
2192                         if (!arg[9] || *end)
2193                                 usage(pack_usage);
2194                         continue;
2195                 }
2196                 if (!prefixcmp(arg, "--window-memory=")) {
2197                         if (!git_parse_ulong(arg+16, &window_memory_limit))
2198                                 usage(pack_usage);
2199                         continue;
2200                 }
2201                 if (!prefixcmp(arg, "--threads=")) {
2202                         char *end;
2203                         delta_search_threads = strtoul(arg+10, &end, 0);
2204                         if (!arg[10] || *end || delta_search_threads < 0)
2205                                 usage(pack_usage);
2206 #ifndef THREADED_DELTA_SEARCH
2207                         if (delta_search_threads != 1)
2208                                 warning("no threads support, "
2209                                         "ignoring %s", arg);
2210 #endif
2211                         continue;
2212                 }
2213                 if (!prefixcmp(arg, "--depth=")) {
2214                         char *end;
2215                         depth = strtoul(arg+8, &end, 0);
2216                         if (!arg[8] || *end)
2217                                 usage(pack_usage);
2218                         continue;
2219                 }
2220                 if (!strcmp("--progress", arg)) {
2221                         progress = 1;
2222                         continue;
2223                 }
2224                 if (!strcmp("--all-progress", arg)) {
2225                         progress = 2;
2226                         continue;
2227                 }
2228                 if (!strcmp("--all-progress-implied", arg)) {
2229                         all_progress_implied = 1;
2230                         continue;
2231                 }
2232                 if (!strcmp("-q", arg)) {
2233                         progress = 0;
2234                         continue;
2235                 }
2236                 if (!strcmp("--no-reuse-delta", arg)) {
2237                         reuse_delta = 0;
2238                         continue;
2239                 }
2240                 if (!strcmp("--no-reuse-object", arg)) {
2241                         reuse_object = reuse_delta = 0;
2242                         continue;
2243                 }
2244                 if (!strcmp("--delta-base-offset", arg)) {
2245                         allow_ofs_delta = 1;
2246                         continue;
2247                 }
2248                 if (!strcmp("--stdout", arg)) {
2249                         pack_to_stdout = 1;
2250                         continue;
2251                 }
2252                 if (!strcmp("--revs", arg)) {
2253                         use_internal_rev_list = 1;
2254                         continue;
2255                 }
2256                 if (!strcmp("--keep-unreachable", arg)) {
2257                         keep_unreachable = 1;
2258                         continue;
2259                 }
2260                 if (!strcmp("--unpack-unreachable", arg)) {
2261                         unpack_unreachable = 1;
2262                         continue;
2263                 }
2264                 if (!strcmp("--include-tag", arg)) {
2265                         include_tag = 1;
2266                         continue;
2267                 }
2268                 if (!strcmp("--unpacked", arg) ||
2269                     !strcmp("--reflog", arg) ||
2270                     !strcmp("--all", arg)) {
2271                         use_internal_rev_list = 1;
2272                         if (rp_ac >= rp_ac_alloc - 1) {
2273                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
2274                                 rp_av = xrealloc(rp_av,
2275                                                  rp_ac_alloc * sizeof(*rp_av));
2276                         }
2277                         rp_av[rp_ac++] = arg;
2278                         continue;
2279                 }
2280                 if (!strcmp("--thin", arg)) {
2281                         use_internal_rev_list = 1;
2282                         thin = 1;
2283                         rp_av[1] = "--objects-edge";
2284                         continue;
2285                 }
2286                 if (!prefixcmp(arg, "--index-version=")) {
2287                         char *c;
2288                         pack_idx_default_version = strtoul(arg + 16, &c, 10);
2289                         if (pack_idx_default_version > 2)
2290                                 die("bad %s", arg);
2291                         if (*c == ',')
2292                                 pack_idx_off32_limit = strtoul(c+1, &c, 0);
2293                         if (*c || pack_idx_off32_limit & 0x80000000)
2294                                 die("bad %s", arg);
2295                         continue;
2296                 }
2297                 if (!strcmp(arg, "--keep-true-parents")) {
2298                         grafts_replace_parents = 0;
2299                         continue;
2300                 }
2301                 usage(pack_usage);
2302         }
2303
2304         /* Traditionally "pack-objects [options] base extra" failed;
2305          * we would however want to take refs parameter that would
2306          * have been given to upstream rev-list ourselves, which means
2307          * we somehow want to say what the base name is.  So the
2308          * syntax would be:
2309          *
2310          * pack-objects [options] base <refs...>
2311          *
2312          * in other words, we would treat the first non-option as the
2313          * base_name and send everything else to the internal revision
2314          * walker.
2315          */
2316
2317         if (!pack_to_stdout)
2318                 base_name = argv[i++];
2319
2320         if (pack_to_stdout != !base_name)
2321                 usage(pack_usage);
2322
2323         if (!pack_to_stdout && !pack_size_limit)
2324                 pack_size_limit = pack_size_limit_cfg;
2325
2326         if (pack_to_stdout && pack_size_limit)
2327                 die("--max-pack-size cannot be used to build a pack for transfer.");
2328
2329         if (!pack_to_stdout && thin)
2330                 die("--thin cannot be used to build an indexable pack.");
2331
2332         if (keep_unreachable && unpack_unreachable)
2333                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
2334
2335         if (progress && all_progress_implied)
2336                 progress = 2;
2337
2338         prepare_packed_git();
2339
2340         if (progress)
2341                 progress_state = start_progress("Counting objects", 0);
2342         if (!use_internal_rev_list)
2343                 read_object_list_from_stdin();
2344         else {
2345                 rp_av[rp_ac] = NULL;
2346                 get_object_list(rp_ac, rp_av);
2347         }
2348         cleanup_preferred_base();
2349         if (include_tag && nr_result)
2350                 for_each_ref(add_ref_tag, NULL);
2351         stop_progress(&progress_state);
2352
2353         if (non_empty && !nr_result)
2354                 return 0;
2355         if (nr_result)
2356                 prepare_pack(window, depth);
2357         write_pack_file();
2358         if (progress)
2359                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
2360                         " reused %"PRIu32" (delta %"PRIu32")\n",
2361                         written, written_delta, reused, reused_delta);
2362         return 0;
2363 }