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

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "attr.h"
   4 #include "object.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "delta.h"
  10 #include "pack.h"
  11 #include "csum-file.h"
  12 #include "tree-walk.h"
  13 #include "diff.h"
  14 #include "revision.h"
  15 #include "list-objects.h"
  16 #include "progress.h"
  17
  18 static const char pack_usage[] = "\
  19 git-pack-objects [{ -q | --progress | --all-progress }] [--max-pack-size=N] \n\
  20         [--local] [--incremental] [--window=N] [--depth=N] \n\
  21         [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
  22         [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
  23         [--stdout | base-name] [<ref-list | <object-list]";
  24
  25 struct object_entry {
  26         unsigned char sha1[20];
  27         uint32_t crc32;         /* crc of raw pack data for this object */
  28         off_t offset;           /* offset into the final pack file */
  29         unsigned long size;     /* uncompressed size */
  30         unsigned int hash;      /* name hint hash */
  31         unsigned int depth;     /* delta depth */
  32         struct packed_git *in_pack;     /* already in pack */
  33         off_t in_pack_offset;
  34         struct object_entry *delta;     /* delta base object */
  35         struct object_entry *delta_child; /* deltified objects who bases me */
  36         struct object_entry *delta_sibling; /* other deltified objects who
  37                                              * uses the same base as me
  38                                              */
  39         void *delta_data;       /* cached delta (uncompressed) */
  40         unsigned long delta_size;       /* delta data size (uncompressed) */
  41         enum object_type type;
  42         enum object_type in_pack_type;  /* could be delta */
  43         unsigned char in_pack_header_size;
  44         unsigned char preferred_base; /* we do not pack this, but is available
  45                                        * to be used as the base object to delta
  46                                        * objects against.
  47                                        */
  48         unsigned char no_try_delta;
  49 };
  50
  51 /*
  52  * Objects we are going to pack are collected in objects array (dynamically
  53  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  54  * in the order we see -- typically rev-list --objects order that gives us
  55  * nice "minimum seek" order.
  56  */
  57 static struct object_entry *objects;
  58 static struct object_entry **written_list;
  59 static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  60
  61 static int non_empty;
  62 static int no_reuse_delta, no_reuse_object;
  63 static int local;
  64 static int incremental;
  65 static int allow_ofs_delta;
  66 static const char *pack_tmp_name, *idx_tmp_name;
  67 static char tmpname[PATH_MAX];
  68 static const char *base_name;
  69 static unsigned char pack_file_sha1[20];
  70 static int progress = 1;
  71 static int window = 10;
  72 static uint32_t pack_size_limit;
  73 static int depth = 50;
  74 static int pack_to_stdout;
  75 static int num_preferred_base;
  76 static struct progress progress_state;
  77 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  78 static int pack_compression_seen;
  79
  80 static unsigned long delta_cache_size = 0;
  81 static unsigned long max_delta_cache_size = 0;
  82 static unsigned long cache_max_small_delta_size = 1000;
  83
  84 /*
  85  * The object names in objects array are hashed with this hashtable,
  86  * to help looking up the entry by object name.
  87  * This hashtable is built after all the objects are seen.
  88  */
  89 static int *object_ix;
  90 static int object_ix_hashsz;
  91
  92 /*
  93  * Pack index for existing packs give us easy access to the offsets into
  94  * corresponding pack file where each object's data starts, but the entries
  95  * do not store the size of the compressed representation (uncompressed
  96  * size is easily available by examining the pack entry header).  It is
  97  * also rather expensive to find the sha1 for an object given its offset.
  98  *
  99  * We build a hashtable of existing packs (pack_revindex), and keep reverse
 100  * index here -- pack index file is sorted by object name mapping to offset;
 101  * this pack_revindex[].revindex array is a list of offset/index_nr pairs
 102  * ordered by offset, so if you know the offset of an object, next offset
 103  * is where its packed representation ends and the index_nr can be used to
 104  * get the object sha1 from the main index.
 105  */
 106 struct revindex_entry {
 107         off_t offset;
 108         unsigned int nr;
 109 };
 110 struct pack_revindex {
 111         struct packed_git *p;
 112         struct revindex_entry *revindex;
 113 };
 114 static struct  pack_revindex *pack_revindex;
 115 static int pack_revindex_hashsz;
 116
 117 /*
 118  * stats
 119  */
 120 static uint32_t written, written_delta;
 121 static uint32_t reused, reused_delta;
 122
 123 static int pack_revindex_ix(struct packed_git *p)
 124 {
 125         unsigned long ui = (unsigned long)p;
 126         int i;
 127
 128         ui = ui ^ (ui >> 16); /* defeat structure alignment */
 129         i = (int)(ui % pack_revindex_hashsz);
 130         while (pack_revindex[i].p) {
 131                 if (pack_revindex[i].p == p)
 132                         return i;
 133                 if (++i == pack_revindex_hashsz)
 134                         i = 0;
 135         }
 136         return -1 - i;
 137 }
 138
 139 static void prepare_pack_ix(void)
 140 {
 141         int num;
 142         struct packed_git *p;
 143         for (num = 0, p = packed_git; p; p = p->next)
 144                 num++;
 145         if (!num)
 146                 return;
 147         pack_revindex_hashsz = num * 11;
 148         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 149         for (p = packed_git; p; p = p->next) {
 150                 num = pack_revindex_ix(p);
 151                 num = - 1 - num;
 152                 pack_revindex[num].p = p;
 153         }
 154         /* revindex elements are lazily initialized */
 155 }
 156
 157 static int cmp_offset(const void *a_, const void *b_)
 158 {
 159         const struct revindex_entry *a = a_;
 160         const struct revindex_entry *b = b_;
 161         return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
 162 }
 163
 164 /*
 165  * Ordered list of offsets of objects in the pack.
 166  */
 167 static void prepare_pack_revindex(struct pack_revindex *rix)
 168 {
 169         struct packed_git *p = rix->p;
 170         int num_ent = p->num_objects;
 171         int i;
 172         const char *index = p->index_data;
 173
 174         rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
 175         index += 4 * 256;
 176
 177         if (p->index_version > 1) {
 178                 const uint32_t *off_32 =
 179                         (uint32_t *)(index + 8 + p->num_objects * (20 + 4));
 180                 const uint32_t *off_64 = off_32 + p->num_objects;
 181                 for (i = 0; i < num_ent; i++) {
 182                         uint32_t off = ntohl(*off_32++);
 183                         if (!(off & 0x80000000)) {
 184                                 rix->revindex[i].offset = off;
 185                         } else {
 186                                 rix->revindex[i].offset =
 187                                         ((uint64_t)ntohl(*off_64++)) << 32;
 188                                 rix->revindex[i].offset |=
 189                                         ntohl(*off_64++);
 190                         }
 191                         rix->revindex[i].nr = i;
 192                 }
 193         } else {
 194                 for (i = 0; i < num_ent; i++) {
 195                         uint32_t hl = *((uint32_t *)(index + 24 * i));
 196                         rix->revindex[i].offset = ntohl(hl);
 197                         rix->revindex[i].nr = i;
 198                 }
 199         }
 200
 201         /* This knows the pack format -- the 20-byte trailer
 202          * follows immediately after the last object data.
 203          */
 204         rix->revindex[num_ent].offset = p->pack_size - 20;
 205         rix->revindex[num_ent].nr = -1;
 206         qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
 207 }
 208
 209 static struct revindex_entry * find_packed_object(struct packed_git *p,
 210                                                   off_t ofs)
 211 {
 212         int num;
 213         int lo, hi;
 214         struct pack_revindex *rix;
 215         struct revindex_entry *revindex;
 216         num = pack_revindex_ix(p);
 217         if (num < 0)
 218                 die("internal error: pack revindex uninitialized");
 219         rix = &pack_revindex[num];
 220         if (!rix->revindex)
 221                 prepare_pack_revindex(rix);
 222         revindex = rix->revindex;
 223         lo = 0;
 224         hi = p->num_objects + 1;
 225         do {
 226                 int mi = (lo + hi) / 2;
 227                 if (revindex[mi].offset == ofs) {
 228                         return revindex + mi;
 229                 }
 230                 else if (ofs < revindex[mi].offset)
 231                         hi = mi;
 232                 else
 233                         lo = mi + 1;
 234         } while (lo < hi);
 235         die("internal error: pack revindex corrupt");
 236 }
 237
 238 static const unsigned char *find_packed_object_name(struct packed_git *p,
 239                                                     off_t ofs)
 240 {
 241         struct revindex_entry *entry = find_packed_object(p, ofs);
 242         return nth_packed_object_sha1(p, entry->nr);
 243 }
 244
 245 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 246 {
 247         unsigned long othersize, delta_size;
 248         enum object_type type;
 249         void *otherbuf = read_sha1_file(entry->delta->sha1, &type, &othersize);
 250         void *delta_buf;
 251
 252         if (!otherbuf)
 253                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 254         delta_buf = diff_delta(otherbuf, othersize,
 255                                buf, size, &delta_size, 0);
 256         if (!delta_buf || delta_size != entry->delta_size)
 257                 die("delta size changed");
 258         free(buf);
 259         free(otherbuf);
 260         return delta_buf;
 261 }
 262
 263 /*
 264  * The per-object header is a pretty dense thing, which is
 265  *  - first byte: low four bits are "size", then three bits of "type",
 266  *    and the high bit is "size continues".
 267  *  - each byte afterwards: low seven bits are size continuation,
 268  *    with the high bit being "size continues"
 269  */
 270 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 271 {
 272         int n = 1;
 273         unsigned char c;
 274
 275         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 276                 die("bad type %d", type);
 277
 278         c = (type << 4) | (size & 15);
 279         size >>= 4;
 280         while (size) {
 281                 *hdr++ = c | 0x80;
 282                 c = size & 0x7f;
 283                 size >>= 7;
 284                 n++;
 285         }
 286         *hdr = c;
 287         return n;
 288 }
 289
 290 /*
 291  * we are going to reuse the existing object data as is.  make
 292  * sure it is not corrupt.
 293  */
 294 static int check_pack_inflate(struct packed_git *p,
 295                 struct pack_window **w_curs,
 296                 off_t offset,
 297                 off_t len,
 298                 unsigned long expect)
 299 {
 300         z_stream stream;
 301         unsigned char fakebuf[4096], *in;
 302         int st;
 303
 304         memset(&stream, 0, sizeof(stream));
 305         inflateInit(&stream);
 306         do {
 307                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 308                 stream.next_in = in;
 309                 stream.next_out = fakebuf;
 310                 stream.avail_out = sizeof(fakebuf);
 311                 st = inflate(&stream, Z_FINISH);
 312                 offset += stream.next_in - in;
 313         } while (st == Z_OK || st == Z_BUF_ERROR);
 314         inflateEnd(&stream);
 315         return (st == Z_STREAM_END &&
 316                 stream.total_out == expect &&
 317                 stream.total_in == len) ? 0 : -1;
 318 }
 319
 320 static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
 321                           off_t offset, off_t len, unsigned int nr)
 322 {
 323         const uint32_t *index_crc;
 324         uint32_t data_crc = crc32(0, Z_NULL, 0);
 325
 326         do {
 327                 unsigned int avail;
 328                 void *data = use_pack(p, w_curs, offset, &avail);
 329                 if (avail > len)
 330                         avail = len;
 331                 data_crc = crc32(data_crc, data, avail);
 332                 offset += avail;
 333                 len -= avail;
 334         } while (len);
 335
 336         index_crc = p->index_data;
 337         index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
 338
 339         return data_crc != ntohl(*index_crc);
 340 }
 341
 342 static void copy_pack_data(struct sha1file *f,
 343                 struct packed_git *p,
 344                 struct pack_window **w_curs,
 345                 off_t offset,
 346                 off_t len)
 347 {
 348         unsigned char *in;
 349         unsigned int avail;
 350
 351         while (len) {
 352                 in = use_pack(p, w_curs, offset, &avail);
 353                 if (avail > len)
 354                         avail = (unsigned int)len;
 355                 sha1write(f, in, avail);
 356                 offset += avail;
 357                 len -= avail;
 358         }
 359 }
 360
 361 static unsigned long write_object(struct sha1file *f,
 362                                   struct object_entry *entry,
 363                                   off_t write_offset)
 364 {
 365         unsigned long size;
 366         enum object_type type;
 367         void *buf;
 368         unsigned char header[10];
 369         unsigned char dheader[10];
 370         unsigned hdrlen;
 371         off_t datalen;
 372         enum object_type obj_type;
 373         int to_reuse = 0;
 374         /* write limit if limited packsize and not first object */
 375         unsigned long limit = pack_size_limit && nr_written ?
 376                                 pack_size_limit - write_offset : 0;
 377                                 /* no if no delta */
 378         int usable_delta =      !entry->delta ? 0 :
 379                                 /* yes if unlimited packfile */
 380                                 !pack_size_limit ? 1 :
 381                                 /* no if base written to previous pack */
 382                                 entry->delta->offset == (off_t)-1 ? 0 :
 383                                 /* otherwise double-check written to this
 384                                  * pack,  like we do below
 385                                  */
 386                                 entry->delta->offset ? 1 : 0;
 387
 388         if (!pack_to_stdout)
 389                 crc32_begin(f);
 390
 391         obj_type = entry->type;
 392         if (no_reuse_object)
 393                 to_reuse = 0;   /* explicit */
 394         else if (!entry->in_pack)
 395                 to_reuse = 0;   /* can't reuse what we don't have */
 396         else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 397                                 /* check_object() decided it for us ... */
 398                 to_reuse = usable_delta;
 399                                 /* ... but pack split may override that */
 400         else if (obj_type != entry->in_pack_type)
 401                 to_reuse = 0;   /* pack has delta which is unusable */
 402         else if (entry->delta)
 403                 to_reuse = 0;   /* we want to pack afresh */
 404         else
 405                 to_reuse = 1;   /* we have it in-pack undeltified,
 406                                  * and we do not need to deltify it.
 407                                  */
 408
 409         if (!to_reuse) {
 410                 z_stream stream;
 411                 unsigned long maxsize;
 412                 void *out;
 413                 if (entry->delta_data && usable_delta) {
 414                         buf = entry->delta_data;
 415                         size = entry->delta_size;
 416                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 417                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 418                 } else {
 419                         buf = read_sha1_file(entry->sha1, &type, &size);
 420                         if (!buf)
 421                                 die("unable to read %s", sha1_to_hex(entry->sha1));
 422                         if (size != entry->size)
 423                                 die("object %s size inconsistency (%lu vs %lu)",
 424                                     sha1_to_hex(entry->sha1), size, entry->size);
 425                         if (usable_delta) {
 426                                 buf = delta_against(buf, size, entry);
 427                                 size = entry->delta_size;
 428                                 obj_type = (allow_ofs_delta && entry->delta->offset) ?
 429                                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 430                         } else {
 431                                 /*
 432                                  * recover real object type in case
 433                                  * check_object() wanted to re-use a delta,
 434                                  * but we couldn't since base was in previous split pack
 435                                  */
 436                                 obj_type = type;
 437                         }
 438                 }
 439                 /* compress the data to store and put compressed length in datalen */
 440                 memset(&stream, 0, sizeof(stream));
 441                 deflateInit(&stream, pack_compression_level);
 442                 maxsize = deflateBound(&stream, size);
 443                 out = xmalloc(maxsize);
 444                 /* Compress it */
 445                 stream.next_in = buf;
 446                 stream.avail_in = size;
 447                 stream.next_out = out;
 448                 stream.avail_out = maxsize;
 449                 while (deflate(&stream, Z_FINISH) == Z_OK)
 450                         /* nothing */;
 451                 deflateEnd(&stream);
 452                 datalen = stream.total_out;
 453                 deflateEnd(&stream);
 454                 /*
 455                  * The object header is a byte of 'type' followed by zero or
 456                  * more bytes of length.
 457                  */
 458                 hdrlen = encode_header(obj_type, size, header);
 459
 460                 if (obj_type == OBJ_OFS_DELTA) {
 461                         /*
 462                          * Deltas with relative base contain an additional
 463                          * encoding of the relative offset for the delta
 464                          * base from this object's position in the pack.
 465                          */
 466                         off_t ofs = entry->offset - entry->delta->offset;
 467                         unsigned pos = sizeof(dheader) - 1;
 468                         dheader[pos] = ofs & 127;
 469                         while (ofs >>= 7)
 470                                 dheader[--pos] = 128 | (--ofs & 127);
 471                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 472                                 free(out);
 473                                 free(buf);
 474                                 return 0;
 475                         }
 476                         sha1write(f, header, hdrlen);
 477                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 478                         hdrlen += sizeof(dheader) - pos;
 479                 } else if (obj_type == OBJ_REF_DELTA) {
 480                         /*
 481                          * Deltas with a base reference contain
 482                          * an additional 20 bytes for the base sha1.
 483                          */
 484                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 485                                 free(out);
 486                                 free(buf);
 487                                 return 0;
 488                         }
 489                         sha1write(f, header, hdrlen);
 490                         sha1write(f, entry->delta->sha1, 20);
 491                         hdrlen += 20;
 492                 } else {
 493                         if (limit && hdrlen + datalen + 20 >= limit) {
 494                                 free(out);
 495                                 free(buf);
 496                                 return 0;
 497                         }
 498                         sha1write(f, header, hdrlen);
 499                 }
 500                 sha1write(f, out, datalen);
 501                 free(out);
 502                 free(buf);
 503         }
 504         else {
 505                 struct packed_git *p = entry->in_pack;
 506                 struct pack_window *w_curs = NULL;
 507                 struct revindex_entry *revidx;
 508                 off_t offset;
 509
 510                 if (entry->delta) {
 511                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 512                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 513                         reused_delta++;
 514                 }
 515                 hdrlen = encode_header(obj_type, entry->size, header);
 516                 offset = entry->in_pack_offset;
 517                 revidx = find_packed_object(p, offset);
 518                 datalen = revidx[1].offset - offset;
 519                 if (!pack_to_stdout && p->index_version > 1 &&
 520                     check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
 521                         die("bad packed object CRC for %s", sha1_to_hex(entry->sha1));
 522                 offset += entry->in_pack_header_size;
 523                 datalen -= entry->in_pack_header_size;
 524                 if (obj_type == OBJ_OFS_DELTA) {
 525                         off_t ofs = entry->offset - entry->delta->offset;
 526                         unsigned pos = sizeof(dheader) - 1;
 527                         dheader[pos] = ofs & 127;
 528                         while (ofs >>= 7)
 529                                 dheader[--pos] = 128 | (--ofs & 127);
 530                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit)
 531                                 return 0;
 532                         sha1write(f, header, hdrlen);
 533                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 534                         hdrlen += sizeof(dheader) - pos;
 535                 } else if (obj_type == OBJ_REF_DELTA) {
 536                         if (limit && hdrlen + 20 + datalen + 20 >= limit)
 537                                 return 0;
 538                         sha1write(f, header, hdrlen);
 539                         sha1write(f, entry->delta->sha1, 20);
 540                         hdrlen += 20;
 541                 } else {
 542                         if (limit && hdrlen + datalen + 20 >= limit)
 543                                 return 0;
 544                         sha1write(f, header, hdrlen);
 545                 }
 546
 547                 if (!pack_to_stdout && p->index_version == 1 &&
 548                     check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
 549                         die("corrupt packed object for %s", sha1_to_hex(entry->sha1));
 550                 copy_pack_data(f, p, &w_curs, offset, datalen);
 551                 unuse_pack(&w_curs);
 552                 reused++;
 553         }
 554         if (usable_delta)
 555                 written_delta++;
 556         written++;
 557         if (!pack_to_stdout)
 558                 entry->crc32 = crc32_end(f);
 559         return hdrlen + datalen;
 560 }
 561
 562 static off_t write_one(struct sha1file *f,
 563                                struct object_entry *e,
 564                                off_t offset)
 565 {
 566         unsigned long size;
 567
 568         /* offset is non zero if object is written already. */
 569         if (e->offset || e->preferred_base)
 570                 return offset;
 571
 572         /* if we are deltified, write out base object first. */
 573         if (e->delta) {
 574                 offset = write_one(f, e->delta, offset);
 575                 if (!offset)
 576                         return 0;
 577         }
 578
 579         e->offset = offset;
 580         size = write_object(f, e, offset);
 581         if (!size) {
 582                 e->offset = 0;
 583                 return 0;
 584         }
 585         written_list[nr_written++] = e;
 586
 587         /* make sure off_t is sufficiently large not to wrap */
 588         if (offset > offset + size)
 589                 die("pack too large for current definition of off_t");
 590         return offset + size;
 591 }
 592
 593 static int open_object_dir_tmp(const char *path)
 594 {
 595     snprintf(tmpname, sizeof(tmpname), "%s/%s", get_object_directory(), path);
 596     return mkstemp(tmpname);
 597 }
 598
 599 /* forward declarations for write_pack_file */
 600 static void write_index_file(off_t last_obj_offset, unsigned char *sha1);
 601 static int adjust_perm(const char *path, mode_t mode);
 602
 603 static void write_pack_file(void)
 604 {
 605         uint32_t i = 0, j;
 606         struct sha1file *f;
 607         off_t offset, offset_one, last_obj_offset = 0;
 608         struct pack_header hdr;
 609         int do_progress = progress >> pack_to_stdout;
 610         uint32_t nr_remaining = nr_result;
 611
 612         if (do_progress)
 613                 start_progress(&progress_state, "Writing %u objects...", "", nr_result);
 614         written_list = xmalloc(nr_objects * sizeof(struct object_entry *));
 615
 616         do {
 617                 if (pack_to_stdout) {
 618                         f = sha1fd(1, "<stdout>");
 619                 } else {
 620                         int fd = open_object_dir_tmp("tmp_pack_XXXXXX");
 621                         if (fd < 0)
 622                                 die("unable to create %s: %s\n", tmpname, strerror(errno));
 623                         pack_tmp_name = xstrdup(tmpname);
 624                         f = sha1fd(fd, pack_tmp_name);
 625                 }
 626
 627                 hdr.hdr_signature = htonl(PACK_SIGNATURE);
 628                 hdr.hdr_version = htonl(PACK_VERSION);
 629                 hdr.hdr_entries = htonl(nr_remaining);
 630                 sha1write(f, &hdr, sizeof(hdr));
 631                 offset = sizeof(hdr);
 632                 nr_written = 0;
 633                 for (; i < nr_objects; i++) {
 634                         last_obj_offset = offset;
 635                         offset_one = write_one(f, objects + i, offset);
 636                         if (!offset_one)
 637                                 break;
 638                         offset = offset_one;
 639                         if (do_progress)
 640                                 display_progress(&progress_state, written);
 641                 }
 642
 643                 /*
 644                  * Did we write the wrong # entries in the header?
 645                  * If so, rewrite it like in fast-import
 646                  */
 647                 if (pack_to_stdout || nr_written == nr_remaining) {
 648                         sha1close(f, pack_file_sha1, 1);
 649                 } else {
 650                         sha1close(f, pack_file_sha1, 0);
 651                         fixup_pack_header_footer(f->fd, pack_file_sha1, pack_tmp_name, nr_written);
 652                         close(f->fd);
 653                 }
 654
 655                 if (!pack_to_stdout) {
 656                         unsigned char object_list_sha1[20];
 657                         mode_t mode = umask(0);
 658
 659                         umask(mode);
 660                         mode = 0444 & ~mode;
 661
 662                         write_index_file(last_obj_offset, object_list_sha1);
 663                         snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
 664                                  base_name, sha1_to_hex(object_list_sha1));
 665                         if (adjust_perm(pack_tmp_name, mode))
 666                                 die("unable to make temporary pack file readable: %s",
 667                                     strerror(errno));
 668                         if (rename(pack_tmp_name, tmpname))
 669                                 die("unable to rename temporary pack file: %s",
 670                                     strerror(errno));
 671                         snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
 672                                  base_name, sha1_to_hex(object_list_sha1));
 673                         if (adjust_perm(idx_tmp_name, mode))
 674                                 die("unable to make temporary index file readable: %s",
 675                                     strerror(errno));
 676                         if (rename(idx_tmp_name, tmpname))
 677                                 die("unable to rename temporary index file: %s",
 678                                     strerror(errno));
 679                         puts(sha1_to_hex(object_list_sha1));
 680                 }
 681
 682                 /* mark written objects as written to previous pack */
 683                 for (j = 0; j < nr_written; j++) {
 684                         written_list[j]->offset = (off_t)-1;
 685                 }
 686                 nr_remaining -= nr_written;
 687         } while (nr_remaining && i < nr_objects);
 688
 689         free(written_list);
 690         if (do_progress)
 691                 stop_progress(&progress_state);
 692         if (written != nr_result)
 693                 die("wrote %u objects while expecting %u", written, nr_result);
 694         /*
 695          * We have scanned through [0 ... i).  Since we have written
 696          * the correct number of objects,  the remaining [i ... nr_objects)
 697          * items must be either already written (due to out-of-order delta base)
 698          * or a preferred base.  Count those which are neither and complain if any.
 699          */
 700         for (j = 0; i < nr_objects; i++) {
 701                 struct object_entry *e = objects + i;
 702                 j += !e->offset && !e->preferred_base;
 703         }
 704         if (j)
 705                 die("wrote %u objects as expected but %u unwritten", written, j);
 706 }
 707
 708 static int sha1_sort(const void *_a, const void *_b)
 709 {
 710         const struct object_entry *a = *(struct object_entry **)_a;
 711         const struct object_entry *b = *(struct object_entry **)_b;
 712         return hashcmp(a->sha1, b->sha1);
 713 }
 714
 715 static uint32_t index_default_version = 1;
 716 static uint32_t index_off32_limit = 0x7fffffff;
 717
 718 static void write_index_file(off_t last_obj_offset, unsigned char *sha1)
 719 {
 720         struct sha1file *f;
 721         struct object_entry **sorted_by_sha, **list, **last;
 722         uint32_t array[256];
 723         uint32_t i, index_version;
 724         SHA_CTX ctx;
 725
 726         int fd = open_object_dir_tmp("tmp_idx_XXXXXX");
 727         if (fd < 0)
 728                 die("unable to create %s: %s\n", tmpname, strerror(errno));
 729         idx_tmp_name = xstrdup(tmpname);
 730         f = sha1fd(fd, idx_tmp_name);
 731
 732         if (nr_written) {
 733                 sorted_by_sha = written_list;
 734                 qsort(sorted_by_sha, nr_written, sizeof(*sorted_by_sha), sha1_sort);
 735                 list = sorted_by_sha;
 736                 last = sorted_by_sha + nr_written;
 737         } else
 738                 sorted_by_sha = list = last = NULL;
 739
 740         /* if last object's offset is >= 2^31 we should use index V2 */
 741         index_version = (last_obj_offset >> 31) ? 2 : index_default_version;
 742
 743         /* index versions 2 and above need a header */
 744         if (index_version >= 2) {
 745                 struct pack_idx_header hdr;
 746                 hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
 747                 hdr.idx_version = htonl(index_version);
 748                 sha1write(f, &hdr, sizeof(hdr));
 749         }
 750
 751         /*
 752          * Write the first-level table (the list is sorted,
 753          * but we use a 256-entry lookup to be able to avoid
 754          * having to do eight extra binary search iterations).
 755          */
 756         for (i = 0; i < 256; i++) {
 757                 struct object_entry **next = list;
 758                 while (next < last) {
 759                         struct object_entry *entry = *next;
 760                         if (entry->sha1[0] != i)
 761                                 break;
 762                         next++;
 763                 }
 764                 array[i] = htonl(next - sorted_by_sha);
 765                 list = next;
 766         }
 767         sha1write(f, array, 256 * 4);
 768
 769         /* Compute the SHA1 hash of sorted object names. */
 770         SHA1_Init(&ctx);
 771
 772         /* Write the actual SHA1 entries. */
 773         list = sorted_by_sha;
 774         for (i = 0; i < nr_written; i++) {
 775                 struct object_entry *entry = *list++;
 776                 if (index_version < 2) {
 777                         uint32_t offset = htonl(entry->offset);
 778                         sha1write(f, &offset, 4);
 779                 }
 780                 sha1write(f, entry->sha1, 20);
 781                 SHA1_Update(&ctx, entry->sha1, 20);
 782         }
 783
 784         if (index_version >= 2) {
 785                 unsigned int nr_large_offset = 0;
 786
 787                 /* write the crc32 table */
 788                 list = sorted_by_sha;
 789                 for (i = 0; i < nr_written; i++) {
 790                         struct object_entry *entry = *list++;
 791                         uint32_t crc32_val = htonl(entry->crc32);
 792                         sha1write(f, &crc32_val, 4);
 793                 }
 794
 795                 /* write the 32-bit offset table */
 796                 list = sorted_by_sha;
 797                 for (i = 0; i < nr_written; i++) {
 798                         struct object_entry *entry = *list++;
 799                         uint32_t offset = (entry->offset <= index_off32_limit) ?
 800                                 entry->offset : (0x80000000 | nr_large_offset++);
 801                         offset = htonl(offset);
 802                         sha1write(f, &offset, 4);
 803                 }
 804
 805                 /* write the large offset table */
 806                 list = sorted_by_sha;
 807                 while (nr_large_offset) {
 808                         struct object_entry *entry = *list++;
 809                         uint64_t offset = entry->offset;
 810                         if (offset > index_off32_limit) {
 811                                 uint32_t split[2];
 812                                 split[0]        = htonl(offset >> 32);
 813                                 split[1] = htonl(offset & 0xffffffff);
 814                                 sha1write(f, split, 8);
 815                                 nr_large_offset--;
 816                         }
 817                 }
 818         }
 819
 820         sha1write(f, pack_file_sha1, 20);
 821         sha1close(f, NULL, 1);
 822         SHA1_Final(sha1, &ctx);
 823 }
 824
 825 static int locate_object_entry_hash(const unsigned char *sha1)
 826 {
 827         int i;
 828         unsigned int ui;
 829         memcpy(&ui, sha1, sizeof(unsigned int));
 830         i = ui % object_ix_hashsz;
 831         while (0 < object_ix[i]) {
 832                 if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
 833                         return i;
 834                 if (++i == object_ix_hashsz)
 835                         i = 0;
 836         }
 837         return -1 - i;
 838 }
 839
 840 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 841 {
 842         int i;
 843
 844         if (!object_ix_hashsz)
 845                 return NULL;
 846
 847         i = locate_object_entry_hash(sha1);
 848         if (0 <= i)
 849                 return &objects[object_ix[i]-1];
 850         return NULL;
 851 }
 852
 853 static void rehash_objects(void)
 854 {
 855         uint32_t i;
 856         struct object_entry *oe;
 857
 858         object_ix_hashsz = nr_objects * 3;
 859         if (object_ix_hashsz < 1024)
 860                 object_ix_hashsz = 1024;
 861         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 862         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 863         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 864                 int ix = locate_object_entry_hash(oe->sha1);
 865                 if (0 <= ix)
 866                         continue;
 867                 ix = -1 - ix;
 868                 object_ix[ix] = i + 1;
 869         }
 870 }
 871
 872 static unsigned name_hash(const char *name)
 873 {
 874         unsigned char c;
 875         unsigned hash = 0;
 876
 877         if (!name)
 878                 return 0;
 879
 880         /*
 881          * This effectively just creates a sortable number from the
 882          * last sixteen non-whitespace characters. Last characters
 883          * count "most", so things that end in ".c" sort together.
 884          */
 885         while ((c = *name++) != 0) {
 886                 if (isspace(c))
 887                         continue;
 888                 hash = (hash >> 2) + (c << 24);
 889         }
 890         return hash;
 891 }
 892
 893 static void setup_delta_attr_check(struct git_attr_check *check)
 894 {
 895         static struct git_attr *attr_delta;
 896
 897         if (!attr_delta)
 898                 attr_delta = git_attr("delta", 5);
 899
 900         check[0].attr = attr_delta;
 901 }
 902
 903 static int no_try_delta(const char *path)
 904 {
 905         struct git_attr_check check[1];
 906
 907         setup_delta_attr_check(check);
 908         if (git_checkattr(path, ARRAY_SIZE(check), check))
 909                 return 0;
 910         if (ATTR_FALSE(check->value))
 911                 return 1;
 912         return 0;
 913 }
 914
 915 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 916                             const char *name, int exclude)
 917 {
 918         struct object_entry *entry;
 919         struct packed_git *p, *found_pack = NULL;
 920         off_t found_offset = 0;
 921         int ix;
 922         unsigned hash = name_hash(name);
 923
 924         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 925         if (ix >= 0) {
 926                 if (exclude) {
 927                         entry = objects + object_ix[ix] - 1;
 928                         if (!entry->preferred_base)
 929                                 nr_result--;
 930                         entry->preferred_base = 1;
 931                 }
 932                 return 0;
 933         }
 934
 935         for (p = packed_git; p; p = p->next) {
 936                 off_t offset = find_pack_entry_one(sha1, p);
 937                 if (offset) {
 938                         if (!found_pack) {
 939                                 found_offset = offset;
 940                                 found_pack = p;
 941                         }
 942                         if (exclude)
 943                                 break;
 944                         if (incremental)
 945                                 return 0;
 946                         if (local && !p->pack_local)
 947                                 return 0;
 948                 }
 949         }
 950
 951         if (nr_objects >= nr_alloc) {
 952                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 953                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 954         }
 955
 956         entry = objects + nr_objects++;
 957         memset(entry, 0, sizeof(*entry));
 958         hashcpy(entry->sha1, sha1);
 959         entry->hash = hash;
 960         if (type)
 961                 entry->type = type;
 962         if (exclude)
 963                 entry->preferred_base = 1;
 964         else
 965                 nr_result++;
 966         if (found_pack) {
 967                 entry->in_pack = found_pack;
 968                 entry->in_pack_offset = found_offset;
 969         }
 970
 971         if (object_ix_hashsz * 3 <= nr_objects * 4)
 972                 rehash_objects();
 973         else
 974                 object_ix[-1 - ix] = nr_objects;
 975
 976         if (progress)
 977                 display_progress(&progress_state, nr_objects);
 978
 979         if (name && no_try_delta(name))
 980                 entry->no_try_delta = 1;
 981
 982         return 1;
 983 }
 984
 985 struct pbase_tree_cache {
 986         unsigned char sha1[20];
 987         int ref;
 988         int temporary;
 989         void *tree_data;
 990         unsigned long tree_size;
 991 };
 992
 993 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 994 static int pbase_tree_cache_ix(const unsigned char *sha1)
 995 {
 996         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 997 }
 998 static int pbase_tree_cache_ix_incr(int ix)
 999 {
1000         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
1001 }
1002
1003 static struct pbase_tree {
1004         struct pbase_tree *next;
1005         /* This is a phony "cache" entry; we are not
1006          * going to evict it nor find it through _get()
1007          * mechanism -- this is for the toplevel node that
1008          * would almost always change with any commit.
1009          */
1010         struct pbase_tree_cache pcache;
1011 } *pbase_tree;
1012
1013 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
1014 {
1015         struct pbase_tree_cache *ent, *nent;
1016         void *data;
1017         unsigned long size;
1018         enum object_type type;
1019         int neigh;
1020         int my_ix = pbase_tree_cache_ix(sha1);
1021         int available_ix = -1;
1022
1023         /* pbase-tree-cache acts as a limited hashtable.
1024          * your object will be found at your index or within a few
1025          * slots after that slot if it is cached.
1026          */
1027         for (neigh = 0; neigh < 8; neigh++) {
1028                 ent = pbase_tree_cache[my_ix];
1029                 if (ent && !hashcmp(ent->sha1, sha1)) {
1030                         ent->ref++;
1031                         return ent;
1032                 }
1033                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
1034                          ((0 <= available_ix) &&
1035                           (!ent && pbase_tree_cache[available_ix])))
1036                         available_ix = my_ix;
1037                 if (!ent)
1038                         break;
1039                 my_ix = pbase_tree_cache_ix_incr(my_ix);
1040         }
1041
1042         /* Did not find one.  Either we got a bogus request or
1043          * we need to read and perhaps cache.
1044          */
1045         data = read_sha1_file(sha1, &type, &size);
1046         if (!data)
1047                 return NULL;
1048         if (type != OBJ_TREE) {
1049                 free(data);
1050                 return NULL;
1051         }
1052
1053         /* We need to either cache or return a throwaway copy */
1054
1055         if (available_ix < 0)
1056                 ent = NULL;
1057         else {
1058                 ent = pbase_tree_cache[available_ix];
1059                 my_ix = available_ix;
1060         }
1061
1062         if (!ent) {
1063                 nent = xmalloc(sizeof(*nent));
1064                 nent->temporary = (available_ix < 0);
1065         }
1066         else {
1067                 /* evict and reuse */
1068                 free(ent->tree_data);
1069                 nent = ent;
1070         }
1071         hashcpy(nent->sha1, sha1);
1072         nent->tree_data = data;
1073         nent->tree_size = size;
1074         nent->ref = 1;
1075         if (!nent->temporary)
1076                 pbase_tree_cache[my_ix] = nent;
1077         return nent;
1078 }
1079
1080 static void pbase_tree_put(struct pbase_tree_cache *cache)
1081 {
1082         if (!cache->temporary) {
1083                 cache->ref--;
1084                 return;
1085         }
1086         free(cache->tree_data);
1087         free(cache);
1088 }
1089
1090 static int name_cmp_len(const char *name)
1091 {
1092         int i;
1093         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1094                 ;
1095         return i;
1096 }
1097
1098 static void add_pbase_object(struct tree_desc *tree,
1099                              const char *name,
1100                              int cmplen,
1101                              const char *fullname)
1102 {
1103         struct name_entry entry;
1104         int cmp;
1105
1106         while (tree_entry(tree,&entry)) {
1107                 cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
1108                       memcmp(name, entry.path, cmplen);
1109                 if (cmp > 0)
1110                         continue;
1111                 if (cmp < 0)
1112                         return;
1113                 if (name[cmplen] != '/') {
1114                         add_object_entry(entry.sha1,
1115                                          S_ISDIR(entry.mode) ? OBJ_TREE : OBJ_BLOB,
1116                                          fullname, 1);
1117                         return;
1118                 }
1119                 if (S_ISDIR(entry.mode)) {
1120                         struct tree_desc sub;
1121                         struct pbase_tree_cache *tree;
1122                         const char *down = name+cmplen+1;
1123                         int downlen = name_cmp_len(down);
1124
1125                         tree = pbase_tree_get(entry.sha1);
1126                         if (!tree)
1127                                 return;
1128                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1129
1130                         add_pbase_object(&sub, down, downlen, fullname);
1131                         pbase_tree_put(tree);
1132                 }
1133         }
1134 }
1135
1136 static unsigned *done_pbase_paths;
1137 static int done_pbase_paths_num;
1138 static int done_pbase_paths_alloc;
1139 static int done_pbase_path_pos(unsigned hash)
1140 {
1141         int lo = 0;
1142         int hi = done_pbase_paths_num;
1143         while (lo < hi) {
1144                 int mi = (hi + lo) / 2;
1145                 if (done_pbase_paths[mi] == hash)
1146                         return mi;
1147                 if (done_pbase_paths[mi] < hash)
1148                         hi = mi;
1149                 else
1150                         lo = mi + 1;
1151         }
1152         return -lo-1;
1153 }
1154
1155 static int check_pbase_path(unsigned hash)
1156 {
1157         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1158         if (0 <= pos)
1159                 return 1;
1160         pos = -pos - 1;
1161         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1162                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1163                 done_pbase_paths = xrealloc(done_pbase_paths,
1164                                             done_pbase_paths_alloc *
1165                                             sizeof(unsigned));
1166         }
1167         done_pbase_paths_num++;
1168         if (pos < done_pbase_paths_num)
1169                 memmove(done_pbase_paths + pos + 1,
1170                         done_pbase_paths + pos,
1171                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1172         done_pbase_paths[pos] = hash;
1173         return 0;
1174 }
1175
1176 static void add_preferred_base_object(const char *name)
1177 {
1178         struct pbase_tree *it;
1179         int cmplen;
1180         unsigned hash = name_hash(name);
1181
1182         if (!num_preferred_base || check_pbase_path(hash))
1183                 return;
1184
1185         cmplen = name_cmp_len(name);
1186         for (it = pbase_tree; it; it = it->next) {
1187                 if (cmplen == 0) {
1188                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1189                 }
1190                 else {
1191                         struct tree_desc tree;
1192                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1193                         add_pbase_object(&tree, name, cmplen, name);
1194                 }
1195         }
1196 }
1197
1198 static void add_preferred_base(unsigned char *sha1)
1199 {
1200         struct pbase_tree *it;
1201         void *data;
1202         unsigned long size;
1203         unsigned char tree_sha1[20];
1204
1205         if (window <= num_preferred_base++)
1206                 return;
1207
1208         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1209         if (!data)
1210                 return;
1211
1212         for (it = pbase_tree; it; it = it->next) {
1213                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1214                         free(data);
1215                         return;
1216                 }
1217         }
1218
1219         it = xcalloc(1, sizeof(*it));
1220         it->next = pbase_tree;
1221         pbase_tree = it;
1222
1223         hashcpy(it->pcache.sha1, tree_sha1);
1224         it->pcache.tree_data = data;
1225         it->pcache.tree_size = size;
1226 }
1227
1228 static void check_object(struct object_entry *entry)
1229 {
1230         if (entry->in_pack) {
1231                 struct packed_git *p = entry->in_pack;
1232                 struct pack_window *w_curs = NULL;
1233                 const unsigned char *base_ref = NULL;
1234                 struct object_entry *base_entry;
1235                 unsigned long used, used_0;
1236                 unsigned int avail;
1237                 off_t ofs;
1238                 unsigned char *buf, c;
1239
1240                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1241
1242                 /*
1243                  * We want in_pack_type even if we do not reuse delta
1244                  * since non-delta representations could still be reused.
1245                  */
1246                 used = unpack_object_header_gently(buf, avail,
1247                                                    &entry->in_pack_type,
1248                                                    &entry->size);
1249
1250                 /*
1251                  * Determine if this is a delta and if so whether we can
1252                  * reuse it or not.  Otherwise let's find out as cheaply as
1253                  * possible what the actual type and size for this object is.
1254                  */
1255                 switch (entry->in_pack_type) {
1256                 default:
1257                         /* Not a delta hence we've already got all we need. */
1258                         entry->type = entry->in_pack_type;
1259                         entry->in_pack_header_size = used;
1260                         unuse_pack(&w_curs);
1261                         return;
1262                 case OBJ_REF_DELTA:
1263                         if (!no_reuse_delta && !entry->preferred_base)
1264                                 base_ref = use_pack(p, &w_curs,
1265                                                 entry->in_pack_offset + used, NULL);
1266                         entry->in_pack_header_size = used + 20;
1267                         break;
1268                 case OBJ_OFS_DELTA:
1269                         buf = use_pack(p, &w_curs,
1270                                        entry->in_pack_offset + used, NULL);
1271                         used_0 = 0;
1272                         c = buf[used_0++];
1273                         ofs = c & 127;
1274                         while (c & 128) {
1275                                 ofs += 1;
1276                                 if (!ofs || MSB(ofs, 7))
1277                                         die("delta base offset overflow in pack for %s",
1278                                             sha1_to_hex(entry->sha1));
1279                                 c = buf[used_0++];
1280                                 ofs = (ofs << 7) + (c & 127);
1281                         }
1282                         if (ofs >= entry->in_pack_offset)
1283                                 die("delta base offset out of bound for %s",
1284                                     sha1_to_hex(entry->sha1));
1285                         ofs = entry->in_pack_offset - ofs;
1286                         if (!no_reuse_delta && !entry->preferred_base)
1287                                 base_ref = find_packed_object_name(p, ofs);
1288                         entry->in_pack_header_size = used + used_0;
1289                         break;
1290                 }
1291
1292                 if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1293                         /*
1294                          * If base_ref was set above that means we wish to
1295                          * reuse delta data, and we even found that base
1296                          * in the list of objects we want to pack. Goodie!
1297                          *
1298                          * Depth value does not matter - find_deltas() will
1299                          * never consider reused delta as the base object to
1300                          * deltify other objects against, in order to avoid
1301                          * circular deltas.
1302                          */
1303                         entry->type = entry->in_pack_type;
1304                         entry->delta = base_entry;
1305                         entry->delta_sibling = base_entry->delta_child;
1306                         base_entry->delta_child = entry;
1307                         unuse_pack(&w_curs);
1308                         return;
1309                 }
1310
1311                 if (entry->type) {
1312                         /*
1313                          * This must be a delta and we already know what the
1314                          * final object type is.  Let's extract the actual
1315                          * object size from the delta header.
1316                          */
1317                         entry->size = get_size_from_delta(p, &w_curs,
1318                                         entry->in_pack_offset + entry->in_pack_header_size);
1319                         unuse_pack(&w_curs);
1320                         return;
1321                 }
1322
1323                 /*
1324                  * No choice but to fall back to the recursive delta walk
1325                  * with sha1_object_info() to find about the object type
1326                  * at this point...
1327                  */
1328                 unuse_pack(&w_curs);
1329         }
1330
1331         entry->type = sha1_object_info(entry->sha1, &entry->size);
1332         if (entry->type < 0)
1333                 die("unable to get type of object %s",
1334                     sha1_to_hex(entry->sha1));
1335 }
1336
1337 static int pack_offset_sort(const void *_a, const void *_b)
1338 {
1339         const struct object_entry *a = *(struct object_entry **)_a;
1340         const struct object_entry *b = *(struct object_entry **)_b;
1341
1342         /* avoid filesystem trashing with loose objects */
1343         if (!a->in_pack && !b->in_pack)
1344                 return hashcmp(a->sha1, b->sha1);
1345
1346         if (a->in_pack < b->in_pack)
1347                 return -1;
1348         if (a->in_pack > b->in_pack)
1349                 return 1;
1350         return a->in_pack_offset < b->in_pack_offset ? -1 :
1351                         (a->in_pack_offset > b->in_pack_offset);
1352 }
1353
1354 static void get_object_details(void)
1355 {
1356         uint32_t i;
1357         struct object_entry **sorted_by_offset;
1358
1359         sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1360         for (i = 0; i < nr_objects; i++)
1361                 sorted_by_offset[i] = objects + i;
1362         qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1363
1364         prepare_pack_ix();
1365         for (i = 0; i < nr_objects; i++)
1366                 check_object(sorted_by_offset[i]);
1367         free(sorted_by_offset);
1368 }
1369
1370 static int type_size_sort(const void *_a, const void *_b)
1371 {
1372         const struct object_entry *a = *(struct object_entry **)_a;
1373         const struct object_entry *b = *(struct object_entry **)_b;
1374
1375         if (a->type < b->type)
1376                 return -1;
1377         if (a->type > b->type)
1378                 return 1;
1379         if (a->hash < b->hash)
1380                 return -1;
1381         if (a->hash > b->hash)
1382                 return 1;
1383         if (a->preferred_base < b->preferred_base)
1384                 return -1;
1385         if (a->preferred_base > b->preferred_base)
1386                 return 1;
1387         if (a->size < b->size)
1388                 return -1;
1389         if (a->size > b->size)
1390                 return 1;
1391         return a > b ? -1 : (a < b);  /* newest last */
1392 }
1393
1394 struct unpacked {
1395         struct object_entry *entry;
1396         void *data;
1397         struct delta_index *index;
1398 };
1399
1400 static int delta_cacheable(struct unpacked *trg, struct unpacked *src,
1401                             unsigned long src_size, unsigned long trg_size,
1402                             unsigned long delta_size)
1403 {
1404         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1405                 return 0;
1406
1407         if (delta_size < cache_max_small_delta_size)
1408                 return 1;
1409
1410         /* cache delta, if objects are large enough compared to delta size */
1411         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1412                 return 1;
1413
1414         return 0;
1415 }
1416
1417 /*
1418  * We search for deltas _backwards_ in a list sorted by type and
1419  * by size, so that we see progressively smaller and smaller files.
1420  * That's because we prefer deltas to be from the bigger file
1421  * to the smaller - deletes are potentially cheaper, but perhaps
1422  * more importantly, the bigger file is likely the more recent
1423  * one.
1424  */
1425 static int try_delta(struct unpacked *trg, struct unpacked *src,
1426                      unsigned max_depth)
1427 {
1428         struct object_entry *trg_entry = trg->entry;
1429         struct object_entry *src_entry = src->entry;
1430         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1431         enum object_type type;
1432         void *delta_buf;
1433
1434         /* Don't bother doing diffs between different types */
1435         if (trg_entry->type != src_entry->type)
1436                 return -1;
1437
1438         /* We do not compute delta to *create* objects we are not
1439          * going to pack.
1440          */
1441         if (trg_entry->preferred_base)
1442                 return -1;
1443
1444         /*
1445          * We do not bother to try a delta that we discarded
1446          * on an earlier try, but only when reusing delta data.
1447          */
1448         if (!no_reuse_delta && trg_entry->in_pack &&
1449             trg_entry->in_pack == src_entry->in_pack &&
1450             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1451             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1452                 return 0;
1453
1454         /* Let's not bust the allowed depth. */
1455         if (src_entry->depth >= max_depth)
1456                 return 0;
1457
1458         /* Now some size filtering heuristics. */
1459         trg_size = trg_entry->size;
1460         max_size = trg_size/2 - 20;
1461         max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1462         if (max_size == 0)
1463                 return 0;
1464         if (trg_entry->delta && trg_entry->delta_size <= max_size)
1465                 max_size = trg_entry->delta_size-1;
1466         src_size = src_entry->size;
1467         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1468         if (sizediff >= max_size)
1469                 return 0;
1470
1471         /* Load data if not already done */
1472         if (!trg->data) {
1473                 trg->data = read_sha1_file(trg_entry->sha1, &type, &sz);
1474                 if (sz != trg_size)
1475                         die("object %s inconsistent object length (%lu vs %lu)",
1476                             sha1_to_hex(trg_entry->sha1), sz, trg_size);
1477         }
1478         if (!src->data) {
1479                 src->data = read_sha1_file(src_entry->sha1, &type, &sz);
1480                 if (sz != src_size)
1481                         die("object %s inconsistent object length (%lu vs %lu)",
1482                             sha1_to_hex(src_entry->sha1), sz, src_size);
1483         }
1484         if (!src->index) {
1485                 src->index = create_delta_index(src->data, src_size);
1486                 if (!src->index) {
1487                         static int warned = 0;
1488                         if (!warned++)
1489                                 warning("suboptimal pack - out of memory");
1490                         return 0;
1491                 }
1492         }
1493
1494         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1495         if (!delta_buf)
1496                 return 0;
1497
1498         if (trg_entry->delta_data) {
1499                 delta_cache_size -= trg_entry->delta_size;
1500                 free(trg_entry->delta_data);
1501         }
1502         trg_entry->delta_data = 0;
1503         trg_entry->delta = src_entry;
1504         trg_entry->delta_size = delta_size;
1505         trg_entry->depth = src_entry->depth + 1;
1506
1507         if (delta_cacheable(src, trg, src_size, trg_size, delta_size)) {
1508                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1509                 delta_cache_size += trg_entry->delta_size;
1510         } else
1511                 free(delta_buf);
1512         return 1;
1513 }
1514
1515 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1516 {
1517         struct object_entry *child = me->delta_child;
1518         unsigned int m = n;
1519         while (child) {
1520                 unsigned int c = check_delta_limit(child, n + 1);
1521                 if (m < c)
1522                         m = c;
1523                 child = child->delta_sibling;
1524         }
1525         return m;
1526 }
1527
1528 static void find_deltas(struct object_entry **list, int window, int depth)
1529 {
1530         uint32_t i = nr_objects, idx = 0, processed = 0;
1531         unsigned int array_size = window * sizeof(struct unpacked);
1532         struct unpacked *array;
1533         int max_depth;
1534
1535         if (!nr_objects)
1536                 return;
1537         array = xmalloc(array_size);
1538         memset(array, 0, array_size);
1539         if (progress)
1540                 start_progress(&progress_state, "Deltifying %u objects...", "", nr_result);
1541
1542         do {
1543                 struct object_entry *entry = list[--i];
1544                 struct unpacked *n = array + idx;
1545                 int j;
1546
1547                 if (!entry->preferred_base)
1548                         processed++;
1549
1550                 if (progress)
1551                         display_progress(&progress_state, processed);
1552
1553                 if (entry->delta)
1554                         /* This happens if we decided to reuse existing
1555                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1556                          */
1557                         continue;
1558
1559                 if (entry->size < 50)
1560                         continue;
1561
1562                 if (entry->no_try_delta)
1563                         continue;
1564
1565                 free_delta_index(n->index);
1566                 n->index = NULL;
1567                 free(n->data);
1568                 n->data = NULL;
1569                 n->entry = entry;
1570
1571                 /*
1572                  * If the current object is at pack edge, take the depth the
1573                  * objects that depend on the current object into account
1574                  * otherwise they would become too deep.
1575                  */
1576                 max_depth = depth;
1577                 if (entry->delta_child) {
1578                         max_depth -= check_delta_limit(entry, 0);
1579                         if (max_depth <= 0)
1580                                 goto next;
1581                 }
1582
1583                 j = window;
1584                 while (--j > 0) {
1585                         uint32_t other_idx = idx + j;
1586                         struct unpacked *m;
1587                         if (other_idx >= window)
1588                                 other_idx -= window;
1589                         m = array + other_idx;
1590                         if (!m->entry)
1591                                 break;
1592                         if (try_delta(n, m, max_depth) < 0)
1593                                 break;
1594                 }
1595
1596                 /* if we made n a delta, and if n is already at max
1597                  * depth, leaving it in the window is pointless.  we
1598                  * should evict it first.
1599                  */
1600                 if (entry->delta && depth <= entry->depth)
1601                         continue;
1602
1603                 next:
1604                 idx++;
1605                 if (idx >= window)
1606                         idx = 0;
1607         } while (i > 0);
1608
1609         if (progress)
1610                 stop_progress(&progress_state);
1611
1612         for (i = 0; i < window; ++i) {
1613                 free_delta_index(array[i].index);
1614                 free(array[i].data);
1615         }
1616         free(array);
1617 }
1618
1619 static void prepare_pack(int window, int depth)
1620 {
1621         struct object_entry **delta_list;
1622         uint32_t i;
1623
1624         get_object_details();
1625
1626         if (!window || !depth)
1627                 return;
1628
1629         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1630         for (i = 0; i < nr_objects; i++)
1631                 delta_list[i] = objects + i;
1632         qsort(delta_list, nr_objects, sizeof(*delta_list), type_size_sort);
1633         find_deltas(delta_list, window+1, depth);
1634         free(delta_list);
1635 }
1636
1637 static int git_pack_config(const char *k, const char *v)
1638 {
1639         if(!strcmp(k, "pack.window")) {
1640                 window = git_config_int(k, v);
1641                 return 0;
1642         }
1643         if(!strcmp(k, "pack.depth")) {
1644                 depth = git_config_int(k, v);
1645                 return 0;
1646         }
1647         if (!strcmp(k, "pack.compression")) {
1648                 int level = git_config_int(k, v);
1649                 if (level == -1)
1650                         level = Z_DEFAULT_COMPRESSION;
1651                 else if (level < 0 || level > Z_BEST_COMPRESSION)
1652                         die("bad pack compression level %d", level);
1653                 pack_compression_level = level;
1654                 pack_compression_seen = 1;
1655                 return 0;
1656         }
1657         if (!strcmp(k, "pack.deltacachesize")) {
1658                 max_delta_cache_size = git_config_int(k, v);
1659                 return 0;
1660         }
1661         if (!strcmp(k, "pack.deltacachelimit")) {
1662                 cache_max_small_delta_size = git_config_int(k, v);
1663                 return 0;
1664         }
1665         return git_default_config(k, v);
1666 }
1667
1668 static void read_object_list_from_stdin(void)
1669 {
1670         char line[40 + 1 + PATH_MAX + 2];
1671         unsigned char sha1[20];
1672
1673         for (;;) {
1674                 if (!fgets(line, sizeof(line), stdin)) {
1675                         if (feof(stdin))
1676                                 break;
1677                         if (!ferror(stdin))
1678                                 die("fgets returned NULL, not EOF, not error!");
1679                         if (errno != EINTR)
1680                                 die("fgets: %s", strerror(errno));
1681                         clearerr(stdin);
1682                         continue;
1683                 }
1684                 if (line[0] == '-') {
1685                         if (get_sha1_hex(line+1, sha1))
1686                                 die("expected edge sha1, got garbage:\n %s",
1687                                     line);
1688                         add_preferred_base(sha1);
1689                         continue;
1690                 }
1691                 if (get_sha1_hex(line, sha1))
1692                         die("expected sha1, got garbage:\n %s", line);
1693
1694                 add_preferred_base_object(line+41);
1695                 add_object_entry(sha1, 0, line+41, 0);
1696         }
1697 }
1698
1699 static void show_commit(struct commit *commit)
1700 {
1701         add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
1702 }
1703
1704 static void show_object(struct object_array_entry *p)
1705 {
1706         add_preferred_base_object(p->name);
1707         add_object_entry(p->item->sha1, p->item->type, p->name, 0);
1708 }
1709
1710 static void show_edge(struct commit *commit)
1711 {
1712         add_preferred_base(commit->object.sha1);
1713 }
1714
1715 static void get_object_list(int ac, const char **av)
1716 {
1717         struct rev_info revs;
1718         char line[1000];
1719         int flags = 0;
1720
1721         init_revisions(&revs, NULL);
1722         save_commit_buffer = 0;
1723         track_object_refs = 0;
1724         setup_revisions(ac, av, &revs, NULL);
1725
1726         while (fgets(line, sizeof(line), stdin) != NULL) {
1727                 int len = strlen(line);
1728                 if (line[len - 1] == '\n')
1729                         line[--len] = 0;
1730                 if (!len)
1731                         break;
1732                 if (*line == '-') {
1733                         if (!strcmp(line, "--not")) {
1734                                 flags ^= UNINTERESTING;
1735                                 continue;
1736                         }
1737                         die("not a rev '%s'", line);
1738                 }
1739                 if (handle_revision_arg(line, &revs, flags, 1))
1740                         die("bad revision '%s'", line);
1741         }
1742
1743         prepare_revision_walk(&revs);
1744         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1745         traverse_commit_list(&revs, show_commit, show_object);
1746 }
1747
1748 static int adjust_perm(const char *path, mode_t mode)
1749 {
1750         if (chmod(path, mode))
1751                 return -1;
1752         return adjust_shared_perm(path);
1753 }
1754
1755 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1756 {
1757         int use_internal_rev_list = 0;
1758         int thin = 0;
1759         uint32_t i;
1760         const char **rp_av;
1761         int rp_ac_alloc = 64;
1762         int rp_ac;
1763
1764         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1765
1766         rp_av[0] = "pack-objects";
1767         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1768         rp_ac = 2;
1769
1770         git_config(git_pack_config);
1771         if (!pack_compression_seen && core_compression_seen)
1772                 pack_compression_level = core_compression_level;
1773
1774         progress = isatty(2);
1775         for (i = 1; i < argc; i++) {
1776                 const char *arg = argv[i];
1777
1778                 if (*arg != '-')
1779                         break;
1780
1781                 if (!strcmp("--non-empty", arg)) {
1782                         non_empty = 1;
1783                         continue;
1784                 }
1785                 if (!strcmp("--local", arg)) {
1786                         local = 1;
1787                         continue;
1788                 }
1789                 if (!strcmp("--incremental", arg)) {
1790                         incremental = 1;
1791                         continue;
1792                 }
1793                 if (!prefixcmp(arg, "--compression=")) {
1794                         char *end;
1795                         int level = strtoul(arg+14, &end, 0);
1796                         if (!arg[14] || *end)
1797                                 usage(pack_usage);
1798                         if (level == -1)
1799                                 level = Z_DEFAULT_COMPRESSION;
1800                         else if (level < 0 || level > Z_BEST_COMPRESSION)
1801                                 die("bad pack compression level %d", level);
1802                         pack_compression_level = level;
1803                         continue;
1804                 }
1805                 if (!prefixcmp(arg, "--max-pack-size=")) {
1806                         char *end;
1807                         pack_size_limit = strtoul(arg+16, &end, 0) * 1024 * 1024;
1808                         if (!arg[16] || *end)
1809                                 usage(pack_usage);
1810                         continue;
1811                 }
1812                 if (!prefixcmp(arg, "--window=")) {
1813                         char *end;
1814                         window = strtoul(arg+9, &end, 0);
1815                         if (!arg[9] || *end)
1816                                 usage(pack_usage);
1817                         continue;
1818                 }
1819                 if (!prefixcmp(arg, "--depth=")) {
1820                         char *end;
1821                         depth = strtoul(arg+8, &end, 0);
1822                         if (!arg[8] || *end)
1823                                 usage(pack_usage);
1824                         continue;
1825                 }
1826                 if (!strcmp("--progress", arg)) {
1827                         progress = 1;
1828                         continue;
1829                 }
1830                 if (!strcmp("--all-progress", arg)) {
1831                         progress = 2;
1832                         continue;
1833                 }
1834                 if (!strcmp("-q", arg)) {
1835                         progress = 0;
1836                         continue;
1837                 }
1838                 if (!strcmp("--no-reuse-delta", arg)) {
1839                         no_reuse_delta = 1;
1840                         continue;
1841                 }
1842                 if (!strcmp("--no-reuse-object", arg)) {
1843                         no_reuse_object = no_reuse_delta = 1;
1844                         continue;
1845                 }
1846                 if (!strcmp("--delta-base-offset", arg)) {
1847                         allow_ofs_delta = 1;
1848                         continue;
1849                 }
1850                 if (!strcmp("--stdout", arg)) {
1851                         pack_to_stdout = 1;
1852                         continue;
1853                 }
1854                 if (!strcmp("--revs", arg)) {
1855                         use_internal_rev_list = 1;
1856                         continue;
1857                 }
1858                 if (!strcmp("--unpacked", arg) ||
1859                     !prefixcmp(arg, "--unpacked=") ||
1860                     !strcmp("--reflog", arg) ||
1861                     !strcmp("--all", arg)) {
1862                         use_internal_rev_list = 1;
1863                         if (rp_ac >= rp_ac_alloc - 1) {
1864                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
1865                                 rp_av = xrealloc(rp_av,
1866                                                  rp_ac_alloc * sizeof(*rp_av));
1867                         }
1868                         rp_av[rp_ac++] = arg;
1869                         continue;
1870                 }
1871                 if (!strcmp("--thin", arg)) {
1872                         use_internal_rev_list = 1;
1873                         thin = 1;
1874                         rp_av[1] = "--objects-edge";
1875                         continue;
1876                 }
1877                 if (!prefixcmp(arg, "--index-version=")) {
1878                         char *c;
1879                         index_default_version = strtoul(arg + 16, &c, 10);
1880                         if (index_default_version > 2)
1881                                 die("bad %s", arg);
1882                         if (*c == ',')
1883                                 index_off32_limit = strtoul(c+1, &c, 0);
1884                         if (*c || index_off32_limit & 0x80000000)
1885                                 die("bad %s", arg);
1886                         continue;
1887                 }
1888                 usage(pack_usage);
1889         }
1890
1891         /* Traditionally "pack-objects [options] base extra" failed;
1892          * we would however want to take refs parameter that would
1893          * have been given to upstream rev-list ourselves, which means
1894          * we somehow want to say what the base name is.  So the
1895          * syntax would be:
1896          *
1897          * pack-objects [options] base <refs...>
1898          *
1899          * in other words, we would treat the first non-option as the
1900          * base_name and send everything else to the internal revision
1901          * walker.
1902          */
1903
1904         if (!pack_to_stdout)
1905                 base_name = argv[i++];
1906
1907         if (pack_to_stdout != !base_name)
1908                 usage(pack_usage);
1909
1910         if (pack_to_stdout && pack_size_limit)
1911                 die("--max-pack-size cannot be used to build a pack for transfer.");
1912
1913         if (!pack_to_stdout && thin)
1914                 die("--thin cannot be used to build an indexable pack.");
1915
1916         prepare_packed_git();
1917
1918         if (progress)
1919                 start_progress(&progress_state, "Generating pack...",
1920                                "Counting objects: ", 0);
1921         if (!use_internal_rev_list)
1922                 read_object_list_from_stdin();
1923         else {
1924                 rp_av[rp_ac] = NULL;
1925                 get_object_list(rp_ac, rp_av);
1926         }
1927         if (progress) {
1928                 stop_progress(&progress_state);
1929                 fprintf(stderr, "Done counting %u objects.\n", nr_objects);
1930         }
1931
1932         if (non_empty && !nr_result)
1933                 return 0;
1934         if (progress && (nr_objects != nr_result))
1935                 fprintf(stderr, "Result has %u objects.\n", nr_result);
1936         if (nr_result)
1937                 prepare_pack(window, depth);
1938         write_pack_file();
1939         if (progress)
1940                 fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
1941                         written, written_delta, reused, reused_delta);
1942         return 0;
1943 }