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

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "object.h"
   4 #include "blob.h"
   5 #include "commit.h"
   6 #include "tag.h"
   7 #include "tree.h"
   8 #include "delta.h"
   9 #include "pack.h"
  10 #include "csum-file.h"
  11 #include "tree-walk.h"
  12 #include "diff.h"
  13 #include "revision.h"
  14 #include "list-objects.h"
  15
  16 static const char pack_usage[] = "\
  17 git-pack-objects [{ -q | --progress | --all-progress }] \n\
  18         [--local] [--incremental] [--window=N] [--depth=N] \n\
  19         [--no-reuse-delta] [--delta-base-offset] [--non-empty] \n\
  20         [--revs [--unpacked | --all]*] [--reflog] [--stdout | base-name] \n\
  21         [<ref-list | <object-list]";
  22
  23 struct object_entry {
  24         unsigned char sha1[20];
  25         uint32_t crc32;         /* crc of raw pack data for this object */
  26         off_t offset;           /* offset into the final pack file */
  27         unsigned long size;     /* uncompressed size */
  28         unsigned int hash;      /* name hint hash */
  29         unsigned int depth;     /* delta depth */
  30         struct packed_git *in_pack;     /* already in pack */
  31         off_t in_pack_offset;
  32         struct object_entry *delta;     /* delta base object */
  33         struct object_entry *delta_child; /* deltified objects who bases me */
  34         struct object_entry *delta_sibling; /* other deltified objects who
  35                                              * uses the same base as me
  36                                              */
  37         unsigned long delta_size;       /* delta data size (uncompressed) */
  38         enum object_type type;
  39         enum object_type in_pack_type;  /* could be delta */
  40         unsigned char in_pack_header_size;
  41         unsigned char preferred_base; /* we do not pack this, but is available
  42                                        * to be used as the base objectto delta
  43                                        * objects against.
  44                                        */
  45 };
  46
  47 /*
  48  * Objects we are going to pack are collected in objects array (dynamically
  49  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  50  * in the order we see -- typically rev-list --objects order that gives us
  51  * nice "minimum seek" order.
  52  *
  53  * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
  54  * elements in the objects array.  The former is used to build the pack
  55  * index (lists object names in the ascending order to help offset lookup),
  56  * and the latter is used to group similar things together by try_delta()
  57  * heuristics.
  58  */
  59
  60 static int non_empty;
  61 static int no_reuse_delta;
  62 static int local;
  63 static int incremental;
  64 static int allow_ofs_delta;
  65
  66 static struct object_entry *objects;
  67 static uint32_t nr_objects, nr_alloc, nr_result;
  68 static const char *pack_tmp_name, *idx_tmp_name;
  69 static char tmpname[PATH_MAX];
  70 static unsigned char pack_file_sha1[20];
  71 static int progress = 1;
  72 static volatile sig_atomic_t progress_update;
  73 static int window = 10;
  74 static int pack_to_stdout;
  75 static int num_preferred_base;
  76
  77 /*
  78  * The object names in objects array are hashed with this hashtable,
  79  * to help looking up the entry by object name.  Binary search from
  80  * sorted_by_sha is also possible but this was easier to code and faster.
  81  * This hashtable is built after all the objects are seen.
  82  */
  83 static int *object_ix;
  84 static int object_ix_hashsz;
  85
  86 /*
  87  * Pack index for existing packs give us easy access to the offsets into
  88  * corresponding pack file where each object's data starts, but the entries
  89  * do not store the size of the compressed representation (uncompressed
  90  * size is easily available by examining the pack entry header).  It is
  91  * also rather expensive to find the sha1 for an object given its offset.
  92  *
  93  * We build a hashtable of existing packs (pack_revindex), and keep reverse
  94  * index here -- pack index file is sorted by object name mapping to offset;
  95  * this pack_revindex[].revindex array is a list of offset/index_nr pairs
  96  * ordered by offset, so if you know the offset of an object, next offset
  97  * is where its packed representation ends and the index_nr can be used to
  98  * get the object sha1 from the main index.
  99  */
 100 struct revindex_entry {
 101         off_t offset;
 102         unsigned int nr;
 103 };
 104 struct pack_revindex {
 105         struct packed_git *p;
 106         struct revindex_entry *revindex;
 107 };
 108 static struct  pack_revindex *pack_revindex;
 109 static int pack_revindex_hashsz;
 110
 111 /*
 112  * stats
 113  */
 114 static uint32_t written, written_delta;
 115 static uint32_t reused, reused_delta;
 116
 117 static int pack_revindex_ix(struct packed_git *p)
 118 {
 119         unsigned long ui = (unsigned long)p;
 120         int i;
 121
 122         ui = ui ^ (ui >> 16); /* defeat structure alignment */
 123         i = (int)(ui % pack_revindex_hashsz);
 124         while (pack_revindex[i].p) {
 125                 if (pack_revindex[i].p == p)
 126                         return i;
 127                 if (++i == pack_revindex_hashsz)
 128                         i = 0;
 129         }
 130         return -1 - i;
 131 }
 132
 133 static void prepare_pack_ix(void)
 134 {
 135         int num;
 136         struct packed_git *p;
 137         for (num = 0, p = packed_git; p; p = p->next)
 138                 num++;
 139         if (!num)
 140                 return;
 141         pack_revindex_hashsz = num * 11;
 142         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 143         for (p = packed_git; p; p = p->next) {
 144                 num = pack_revindex_ix(p);
 145                 num = - 1 - num;
 146                 pack_revindex[num].p = p;
 147         }
 148         /* revindex elements are lazily initialized */
 149 }
 150
 151 static int cmp_offset(const void *a_, const void *b_)
 152 {
 153         const struct revindex_entry *a = a_;
 154         const struct revindex_entry *b = b_;
 155         return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
 156 }
 157
 158 /*
 159  * Ordered list of offsets of objects in the pack.
 160  */
 161 static void prepare_pack_revindex(struct pack_revindex *rix)
 162 {
 163         struct packed_git *p = rix->p;
 164         int num_ent = p->num_objects;
 165         int i;
 166         const char *index = p->index_data;
 167
 168         rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
 169         index += 4 * 256;
 170
 171         if (p->index_version > 1) {
 172                 const uint32_t *off_32 =
 173                         (uint32_t *)(index + 8 + p->num_objects * (20 + 4));
 174                 const uint32_t *off_64 = off_32 + p->num_objects;
 175                 for (i = 0; i < num_ent; i++) {
 176                         uint32_t off = ntohl(*off_32++);
 177                         if (!(off & 0x80000000)) {
 178                                 rix->revindex[i].offset = off;
 179                         } else {
 180                                 rix->revindex[i].offset =
 181                                         ((uint64_t)ntohl(*off_64++)) << 32;
 182                                 rix->revindex[i].offset |=
 183                                         ntohl(*off_64++);
 184                         }
 185                         rix->revindex[i].nr = i;
 186                 }
 187         } else {
 188                 for (i = 0; i < num_ent; i++) {
 189                         uint32_t hl = *((uint32_t *)(index + 24 * i));
 190                         rix->revindex[i].offset = ntohl(hl);
 191                         rix->revindex[i].nr = i;
 192                 }
 193         }
 194
 195         /* This knows the pack format -- the 20-byte trailer
 196          * follows immediately after the last object data.
 197          */
 198         rix->revindex[num_ent].offset = p->pack_size - 20;
 199         rix->revindex[num_ent].nr = -1;
 200         qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
 201 }
 202
 203 static struct revindex_entry * find_packed_object(struct packed_git *p,
 204                                                   off_t ofs)
 205 {
 206         int num;
 207         int lo, hi;
 208         struct pack_revindex *rix;
 209         struct revindex_entry *revindex;
 210         num = pack_revindex_ix(p);
 211         if (num < 0)
 212                 die("internal error: pack revindex uninitialized");
 213         rix = &pack_revindex[num];
 214         if (!rix->revindex)
 215                 prepare_pack_revindex(rix);
 216         revindex = rix->revindex;
 217         lo = 0;
 218         hi = p->num_objects + 1;
 219         do {
 220                 int mi = (lo + hi) / 2;
 221                 if (revindex[mi].offset == ofs) {
 222                         return revindex + mi;
 223                 }
 224                 else if (ofs < revindex[mi].offset)
 225                         hi = mi;
 226                 else
 227                         lo = mi + 1;
 228         } while (lo < hi);
 229         die("internal error: pack revindex corrupt");
 230 }
 231
 232 static const unsigned char *find_packed_object_name(struct packed_git *p,
 233                                                     off_t ofs)
 234 {
 235         struct revindex_entry *entry = find_packed_object(p, ofs);
 236         return nth_packed_object_sha1(p, entry->nr);
 237 }
 238
 239 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 240 {
 241         unsigned long othersize, delta_size;
 242         enum object_type type;
 243         void *otherbuf = read_sha1_file(entry->delta->sha1, &type, &othersize);
 244         void *delta_buf;
 245
 246         if (!otherbuf)
 247                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 248         delta_buf = diff_delta(otherbuf, othersize,
 249                                buf, size, &delta_size, 0);
 250         if (!delta_buf || delta_size != entry->delta_size)
 251                 die("delta size changed");
 252         free(buf);
 253         free(otherbuf);
 254         return delta_buf;
 255 }
 256
 257 /*
 258  * The per-object header is a pretty dense thing, which is
 259  *  - first byte: low four bits are "size", then three bits of "type",
 260  *    and the high bit is "size continues".
 261  *  - each byte afterwards: low seven bits are size continuation,
 262  *    with the high bit being "size continues"
 263  */
 264 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 265 {
 266         int n = 1;
 267         unsigned char c;
 268
 269         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 270                 die("bad type %d", type);
 271
 272         c = (type << 4) | (size & 15);
 273         size >>= 4;
 274         while (size) {
 275                 *hdr++ = c | 0x80;
 276                 c = size & 0x7f;
 277                 size >>= 7;
 278                 n++;
 279         }
 280         *hdr = c;
 281         return n;
 282 }
 283
 284 /*
 285  * we are going to reuse the existing object data as is.  make
 286  * sure it is not corrupt.
 287  */
 288 static int check_pack_inflate(struct packed_git *p,
 289                 struct pack_window **w_curs,
 290                 off_t offset,
 291                 off_t len,
 292                 unsigned long expect)
 293 {
 294         z_stream stream;
 295         unsigned char fakebuf[4096], *in;
 296         int st;
 297
 298         memset(&stream, 0, sizeof(stream));
 299         inflateInit(&stream);
 300         do {
 301                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 302                 stream.next_in = in;
 303                 stream.next_out = fakebuf;
 304                 stream.avail_out = sizeof(fakebuf);
 305                 st = inflate(&stream, Z_FINISH);
 306                 offset += stream.next_in - in;
 307         } while (st == Z_OK || st == Z_BUF_ERROR);
 308         inflateEnd(&stream);
 309         return (st == Z_STREAM_END &&
 310                 stream.total_out == expect &&
 311                 stream.total_in == len) ? 0 : -1;
 312 }
 313
 314 static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
 315                           off_t offset, off_t len, unsigned int nr)
 316 {
 317         const uint32_t *index_crc;
 318         uint32_t data_crc = crc32(0, Z_NULL, 0);
 319
 320         do {
 321                 unsigned int avail;
 322                 void *data = use_pack(p, w_curs, offset, &avail);
 323                 if (avail > len)
 324                         avail = len;
 325                 data_crc = crc32(data_crc, data, avail);
 326                 offset += avail;
 327                 len -= avail;
 328         } while (len);
 329
 330         index_crc = p->index_data;
 331         index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
 332
 333         return data_crc != ntohl(*index_crc);
 334 }
 335
 336 static void copy_pack_data(struct sha1file *f,
 337                 struct packed_git *p,
 338                 struct pack_window **w_curs,
 339                 off_t offset,
 340                 off_t len)
 341 {
 342         unsigned char *in;
 343         unsigned int avail;
 344
 345         while (len) {
 346                 in = use_pack(p, w_curs, offset, &avail);
 347                 if (avail > len)
 348                         avail = (unsigned int)len;
 349                 sha1write(f, in, avail);
 350                 offset += avail;
 351                 len -= avail;
 352         }
 353 }
 354
 355 static int check_loose_inflate(unsigned char *data, unsigned long len, unsigned long expect)
 356 {
 357         z_stream stream;
 358         unsigned char fakebuf[4096];
 359         int st;
 360
 361         memset(&stream, 0, sizeof(stream));
 362         stream.next_in = data;
 363         stream.avail_in = len;
 364         stream.next_out = fakebuf;
 365         stream.avail_out = sizeof(fakebuf);
 366         inflateInit(&stream);
 367
 368         while (1) {
 369                 st = inflate(&stream, Z_FINISH);
 370                 if (st == Z_STREAM_END || st == Z_OK) {
 371                         st = (stream.total_out == expect &&
 372                               stream.total_in == len) ? 0 : -1;
 373                         break;
 374                 }
 375                 if (st != Z_BUF_ERROR) {
 376                         st = -1;
 377                         break;
 378                 }
 379                 stream.next_out = fakebuf;
 380                 stream.avail_out = sizeof(fakebuf);
 381         }
 382         inflateEnd(&stream);
 383         return st;
 384 }
 385
 386 static int revalidate_loose_object(struct object_entry *entry,
 387                                    unsigned char *map,
 388                                    unsigned long mapsize)
 389 {
 390         /* we already know this is a loose object with new type header. */
 391         enum object_type type;
 392         unsigned long size, used;
 393
 394         if (pack_to_stdout)
 395                 return 0;
 396
 397         used = unpack_object_header_gently(map, mapsize, &type, &size);
 398         if (!used)
 399                 return -1;
 400         map += used;
 401         mapsize -= used;
 402         return check_loose_inflate(map, mapsize, size);
 403 }
 404
 405 static unsigned long write_object(struct sha1file *f,
 406                                   struct object_entry *entry)
 407 {
 408         unsigned long size;
 409         enum object_type type;
 410         void *buf;
 411         unsigned char header[10];
 412         unsigned hdrlen;
 413         off_t datalen;
 414         enum object_type obj_type;
 415         int to_reuse = 0;
 416
 417         if (!pack_to_stdout)
 418                 crc32_begin(f);
 419
 420         obj_type = entry->type;
 421         if (! entry->in_pack)
 422                 to_reuse = 0;   /* can't reuse what we don't have */
 423         else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 424                 to_reuse = 1;   /* check_object() decided it for us */
 425         else if (obj_type != entry->in_pack_type)
 426                 to_reuse = 0;   /* pack has delta which is unusable */
 427         else if (entry->delta)
 428                 to_reuse = 0;   /* we want to pack afresh */
 429         else
 430                 to_reuse = 1;   /* we have it in-pack undeltified,
 431                                  * and we do not need to deltify it.
 432                                  */
 433
 434         if (!entry->in_pack && !entry->delta) {
 435                 unsigned char *map;
 436                 unsigned long mapsize;
 437                 map = map_sha1_file(entry->sha1, &mapsize);
 438                 if (map && !legacy_loose_object(map)) {
 439                         /* We can copy straight into the pack file */
 440                         if (revalidate_loose_object(entry, map, mapsize))
 441                                 die("corrupt loose object %s",
 442                                     sha1_to_hex(entry->sha1));
 443                         sha1write(f, map, mapsize);
 444                         munmap(map, mapsize);
 445                         written++;
 446                         reused++;
 447                         return mapsize;
 448                 }
 449                 if (map)
 450                         munmap(map, mapsize);
 451         }
 452
 453         if (!to_reuse) {
 454                 buf = read_sha1_file(entry->sha1, &type, &size);
 455                 if (!buf)
 456                         die("unable to read %s", sha1_to_hex(entry->sha1));
 457                 if (size != entry->size)
 458                         die("object %s size inconsistency (%lu vs %lu)",
 459                             sha1_to_hex(entry->sha1), size, entry->size);
 460                 if (entry->delta) {
 461                         buf = delta_against(buf, size, entry);
 462                         size = entry->delta_size;
 463                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 464                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 465                 }
 466                 /*
 467                  * The object header is a byte of 'type' followed by zero or
 468                  * more bytes of length.
 469                  */
 470                 hdrlen = encode_header(obj_type, size, header);
 471                 sha1write(f, header, hdrlen);
 472
 473                 if (obj_type == OBJ_OFS_DELTA) {
 474                         /*
 475                          * Deltas with relative base contain an additional
 476                          * encoding of the relative offset for the delta
 477                          * base from this object's position in the pack.
 478                          */
 479                         off_t ofs = entry->offset - entry->delta->offset;
 480                         unsigned pos = sizeof(header) - 1;
 481                         header[pos] = ofs & 127;
 482                         while (ofs >>= 7)
 483                                 header[--pos] = 128 | (--ofs & 127);
 484                         sha1write(f, header + pos, sizeof(header) - pos);
 485                         hdrlen += sizeof(header) - pos;
 486                 } else if (obj_type == OBJ_REF_DELTA) {
 487                         /*
 488                          * Deltas with a base reference contain
 489                          * an additional 20 bytes for the base sha1.
 490                          */
 491                         sha1write(f, entry->delta->sha1, 20);
 492                         hdrlen += 20;
 493                 }
 494                 datalen = sha1write_compressed(f, buf, size);
 495                 free(buf);
 496         }
 497         else {
 498                 struct packed_git *p = entry->in_pack;
 499                 struct pack_window *w_curs = NULL;
 500                 struct revindex_entry *revidx;
 501                 off_t offset;
 502
 503                 if (entry->delta) {
 504                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 505                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 506                         reused_delta++;
 507                 }
 508                 hdrlen = encode_header(obj_type, entry->size, header);
 509                 sha1write(f, header, hdrlen);
 510                 if (obj_type == OBJ_OFS_DELTA) {
 511                         off_t ofs = entry->offset - entry->delta->offset;
 512                         unsigned pos = sizeof(header) - 1;
 513                         header[pos] = ofs & 127;
 514                         while (ofs >>= 7)
 515                                 header[--pos] = 128 | (--ofs & 127);
 516                         sha1write(f, header + pos, sizeof(header) - pos);
 517                         hdrlen += sizeof(header) - pos;
 518                 } else if (obj_type == OBJ_REF_DELTA) {
 519                         sha1write(f, entry->delta->sha1, 20);
 520                         hdrlen += 20;
 521                 }
 522
 523                 offset = entry->in_pack_offset;
 524                 revidx = find_packed_object(p, offset);
 525                 datalen = revidx[1].offset - offset;
 526                 if (!pack_to_stdout && p->index_version > 1 &&
 527                     check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
 528                         die("bad packed object CRC for %s", sha1_to_hex(entry->sha1));
 529                 offset += entry->in_pack_header_size;
 530                 datalen -= entry->in_pack_header_size;
 531                 if (!pack_to_stdout && p->index_version == 1 &&
 532                     check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
 533                         die("corrupt packed object for %s", sha1_to_hex(entry->sha1));
 534                 copy_pack_data(f, p, &w_curs, offset, datalen);
 535                 unuse_pack(&w_curs);
 536                 reused++;
 537         }
 538         if (entry->delta)
 539                 written_delta++;
 540         written++;
 541         if (!pack_to_stdout)
 542                 entry->crc32 = crc32_end(f);
 543         return hdrlen + datalen;
 544 }
 545
 546 static off_t write_one(struct sha1file *f,
 547                                struct object_entry *e,
 548                                off_t offset)
 549 {
 550         unsigned long size;
 551
 552         /* offset is non zero if object is written already. */
 553         if (e->offset || e->preferred_base)
 554                 return offset;
 555
 556         /* if we are deltified, write out base object first. */
 557         if (e->delta)
 558                 offset = write_one(f, e->delta, offset);
 559
 560         e->offset = offset;
 561         size = write_object(f, e);
 562
 563         /* make sure off_t is sufficiently large not to wrap */
 564         if (offset > offset + size)
 565                 die("pack too large for current definition of off_t");
 566         return offset + size;
 567 }
 568
 569 static off_t write_pack_file(void)
 570 {
 571         uint32_t i;
 572         struct sha1file *f;
 573         off_t offset, last_obj_offset = 0;
 574         struct pack_header hdr;
 575         unsigned last_percent = 999;
 576         int do_progress = progress;
 577
 578         if (pack_to_stdout) {
 579                 f = sha1fd(1, "<stdout>");
 580                 do_progress >>= 1;
 581         } else {
 582                 int fd;
 583                 snprintf(tmpname, sizeof(tmpname), "tmp_pack_XXXXXX");
 584                 fd = mkstemp(tmpname);
 585                 if (fd < 0)
 586                         die("unable to create %s: %s\n", tmpname, strerror(errno));
 587                 pack_tmp_name = xstrdup(tmpname);
 588                 f = sha1fd(fd, pack_tmp_name);
 589         }
 590
 591         if (do_progress)
 592                 fprintf(stderr, "Writing %u objects.\n", nr_result);
 593
 594         hdr.hdr_signature = htonl(PACK_SIGNATURE);
 595         hdr.hdr_version = htonl(PACK_VERSION);
 596         hdr.hdr_entries = htonl(nr_result);
 597         sha1write(f, &hdr, sizeof(hdr));
 598         offset = sizeof(hdr);
 599         if (!nr_result)
 600                 goto done;
 601         for (i = 0; i < nr_objects; i++) {
 602                 last_obj_offset = offset;
 603                 offset = write_one(f, objects + i, offset);
 604                 if (do_progress) {
 605                         unsigned percent = written * 100 / nr_result;
 606                         if (progress_update || percent != last_percent) {
 607                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
 608                                         percent, written, nr_result);
 609                                 progress_update = 0;
 610                                 last_percent = percent;
 611                         }
 612                 }
 613         }
 614         if (do_progress)
 615                 fputc('\n', stderr);
 616  done:
 617         if (written != nr_result)
 618                 die("wrote %u objects while expecting %u", written, nr_result);
 619         sha1close(f, pack_file_sha1, 1);
 620
 621         return last_obj_offset;
 622 }
 623
 624 static int sha1_sort(const void *_a, const void *_b)
 625 {
 626         const struct object_entry *a = *(struct object_entry **)_a;
 627         const struct object_entry *b = *(struct object_entry **)_b;
 628         return hashcmp(a->sha1, b->sha1);
 629 }
 630
 631 static uint32_t index_default_version = 1;
 632 static uint32_t index_off32_limit = 0x7fffffff;
 633
 634 static void write_index_file(off_t last_obj_offset, unsigned char *sha1)
 635 {
 636         struct sha1file *f;
 637         struct object_entry **sorted_by_sha, **list, **last;
 638         uint32_t array[256];
 639         uint32_t i, index_version;
 640         SHA_CTX ctx;
 641         int fd;
 642
 643         snprintf(tmpname, sizeof(tmpname), "tmp_idx_XXXXXX");
 644         fd = mkstemp(tmpname);
 645         if (fd < 0)
 646                 die("unable to create %s: %s\n", tmpname, strerror(errno));
 647         idx_tmp_name = xstrdup(tmpname);
 648         f = sha1fd(fd, idx_tmp_name);
 649
 650         if (nr_result) {
 651                 uint32_t j = 0;
 652                 sorted_by_sha =
 653                         xcalloc(nr_result, sizeof(struct object_entry *));
 654                 for (i = 0; i < nr_objects; i++)
 655                         if (!objects[i].preferred_base)
 656                                 sorted_by_sha[j++] = objects + i;
 657                 if (j != nr_result)
 658                         die("listed %u objects while expecting %u", j, nr_result);
 659                 qsort(sorted_by_sha, nr_result, sizeof(*sorted_by_sha), sha1_sort);
 660                 list = sorted_by_sha;
 661                 last = sorted_by_sha + nr_result;
 662         } else
 663                 sorted_by_sha = list = last = NULL;
 664
 665         /* if last object's offset is >= 2^31 we should use index V2 */
 666         index_version = (last_obj_offset >> 31) ? 2 : index_default_version;
 667
 668         /* index versions 2 and above need a header */
 669         if (index_version >= 2) {
 670                 struct pack_idx_header hdr;
 671                 hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
 672                 hdr.idx_version = htonl(index_version);
 673                 sha1write(f, &hdr, sizeof(hdr));
 674         }
 675
 676         /*
 677          * Write the first-level table (the list is sorted,
 678          * but we use a 256-entry lookup to be able to avoid
 679          * having to do eight extra binary search iterations).
 680          */
 681         for (i = 0; i < 256; i++) {
 682                 struct object_entry **next = list;
 683                 while (next < last) {
 684                         struct object_entry *entry = *next;
 685                         if (entry->sha1[0] != i)
 686                                 break;
 687                         next++;
 688                 }
 689                 array[i] = htonl(next - sorted_by_sha);
 690                 list = next;
 691         }
 692         sha1write(f, array, 256 * 4);
 693
 694         /* Compute the SHA1 hash of sorted object names. */
 695         SHA1_Init(&ctx);
 696
 697         /* Write the actual SHA1 entries. */
 698         list = sorted_by_sha;
 699         for (i = 0; i < nr_result; i++) {
 700                 struct object_entry *entry = *list++;
 701                 if (index_version < 2) {
 702                         uint32_t offset = htonl(entry->offset);
 703                         sha1write(f, &offset, 4);
 704                 }
 705                 sha1write(f, entry->sha1, 20);
 706                 SHA1_Update(&ctx, entry->sha1, 20);
 707         }
 708
 709         if (index_version >= 2) {
 710                 unsigned int nr_large_offset = 0;
 711
 712                 /* write the crc32 table */
 713                 list = sorted_by_sha;
 714                 for (i = 0; i < nr_objects; i++) {
 715                         struct object_entry *entry = *list++;
 716                         uint32_t crc32_val = htonl(entry->crc32);
 717                         sha1write(f, &crc32_val, 4);
 718                 }
 719
 720                 /* write the 32-bit offset table */
 721                 list = sorted_by_sha;
 722                 for (i = 0; i < nr_objects; i++) {
 723                         struct object_entry *entry = *list++;
 724                         uint32_t offset = (entry->offset <= index_off32_limit) ?
 725                                 entry->offset : (0x80000000 | nr_large_offset++);
 726                         offset = htonl(offset);
 727                         sha1write(f, &offset, 4);
 728                 }
 729
 730                 /* write the large offset table */
 731                 list = sorted_by_sha;
 732                 while (nr_large_offset) {
 733                         struct object_entry *entry = *list++;
 734                         uint64_t offset = entry->offset;
 735                         if (offset > index_off32_limit) {
 736                                 uint32_t split[2];
 737                                 split[0]        = htonl(offset >> 32);
 738                                 split[1] = htonl(offset & 0xffffffff);
 739                                 sha1write(f, split, 8);
 740                                 nr_large_offset--;
 741                         }
 742                 }
 743         }
 744
 745         sha1write(f, pack_file_sha1, 20);
 746         sha1close(f, NULL, 1);
 747         free(sorted_by_sha);
 748         SHA1_Final(sha1, &ctx);
 749 }
 750
 751 static int locate_object_entry_hash(const unsigned char *sha1)
 752 {
 753         int i;
 754         unsigned int ui;
 755         memcpy(&ui, sha1, sizeof(unsigned int));
 756         i = ui % object_ix_hashsz;
 757         while (0 < object_ix[i]) {
 758                 if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
 759                         return i;
 760                 if (++i == object_ix_hashsz)
 761                         i = 0;
 762         }
 763         return -1 - i;
 764 }
 765
 766 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 767 {
 768         int i;
 769
 770         if (!object_ix_hashsz)
 771                 return NULL;
 772
 773         i = locate_object_entry_hash(sha1);
 774         if (0 <= i)
 775                 return &objects[object_ix[i]-1];
 776         return NULL;
 777 }
 778
 779 static void rehash_objects(void)
 780 {
 781         uint32_t i;
 782         struct object_entry *oe;
 783
 784         object_ix_hashsz = nr_objects * 3;
 785         if (object_ix_hashsz < 1024)
 786                 object_ix_hashsz = 1024;
 787         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 788         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 789         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 790                 int ix = locate_object_entry_hash(oe->sha1);
 791                 if (0 <= ix)
 792                         continue;
 793                 ix = -1 - ix;
 794                 object_ix[ix] = i + 1;
 795         }
 796 }
 797
 798 static unsigned name_hash(const char *name)
 799 {
 800         unsigned char c;
 801         unsigned hash = 0;
 802
 803         /*
 804          * This effectively just creates a sortable number from the
 805          * last sixteen non-whitespace characters. Last characters
 806          * count "most", so things that end in ".c" sort together.
 807          */
 808         while ((c = *name++) != 0) {
 809                 if (isspace(c))
 810                         continue;
 811                 hash = (hash >> 2) + (c << 24);
 812         }
 813         return hash;
 814 }
 815
 816 static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 817 {
 818         struct object_entry *entry;
 819         struct packed_git *p, *found_pack = NULL;
 820         off_t found_offset = 0;
 821         int ix;
 822
 823         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 824         if (ix >= 0) {
 825                 if (exclude) {
 826                         entry = objects + object_ix[ix] - 1;
 827                         if (!entry->preferred_base)
 828                                 nr_result--;
 829                         entry->preferred_base = 1;
 830                 }
 831                 return 0;
 832         }
 833
 834         if (!exclude) {
 835                 for (p = packed_git; p; p = p->next) {
 836                         off_t offset = find_pack_entry_one(sha1, p);
 837                         if (offset) {
 838                                 if (incremental)
 839                                         return 0;
 840                                 if (local && !p->pack_local)
 841                                         return 0;
 842                                 if (!found_pack) {
 843                                         found_offset = offset;
 844                                         found_pack = p;
 845                                 }
 846                         }
 847                 }
 848         }
 849
 850         if (nr_objects >= nr_alloc) {
 851                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 852                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 853         }
 854
 855         entry = objects + nr_objects++;
 856         memset(entry, 0, sizeof(*entry));
 857         hashcpy(entry->sha1, sha1);
 858         entry->hash = hash;
 859         if (exclude)
 860                 entry->preferred_base = 1;
 861         else
 862                 nr_result++;
 863         if (found_pack) {
 864                 entry->in_pack = found_pack;
 865                 entry->in_pack_offset = found_offset;
 866         }
 867
 868         if (object_ix_hashsz * 3 <= nr_objects * 4)
 869                 rehash_objects();
 870         else
 871                 object_ix[-1 - ix] = nr_objects;
 872
 873         if (progress_update) {
 874                 fprintf(stderr, "Counting objects...%u\r", nr_objects);
 875                 progress_update = 0;
 876         }
 877
 878         return 1;
 879 }
 880
 881 struct pbase_tree_cache {
 882         unsigned char sha1[20];
 883         int ref;
 884         int temporary;
 885         void *tree_data;
 886         unsigned long tree_size;
 887 };
 888
 889 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 890 static int pbase_tree_cache_ix(const unsigned char *sha1)
 891 {
 892         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 893 }
 894 static int pbase_tree_cache_ix_incr(int ix)
 895 {
 896         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 897 }
 898
 899 static struct pbase_tree {
 900         struct pbase_tree *next;
 901         /* This is a phony "cache" entry; we are not
 902          * going to evict it nor find it through _get()
 903          * mechanism -- this is for the toplevel node that
 904          * would almost always change with any commit.
 905          */
 906         struct pbase_tree_cache pcache;
 907 } *pbase_tree;
 908
 909 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 910 {
 911         struct pbase_tree_cache *ent, *nent;
 912         void *data;
 913         unsigned long size;
 914         enum object_type type;
 915         int neigh;
 916         int my_ix = pbase_tree_cache_ix(sha1);
 917         int available_ix = -1;
 918
 919         /* pbase-tree-cache acts as a limited hashtable.
 920          * your object will be found at your index or within a few
 921          * slots after that slot if it is cached.
 922          */
 923         for (neigh = 0; neigh < 8; neigh++) {
 924                 ent = pbase_tree_cache[my_ix];
 925                 if (ent && !hashcmp(ent->sha1, sha1)) {
 926                         ent->ref++;
 927                         return ent;
 928                 }
 929                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 930                          ((0 <= available_ix) &&
 931                           (!ent && pbase_tree_cache[available_ix])))
 932                         available_ix = my_ix;
 933                 if (!ent)
 934                         break;
 935                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 936         }
 937
 938         /* Did not find one.  Either we got a bogus request or
 939          * we need to read and perhaps cache.
 940          */
 941         data = read_sha1_file(sha1, &type, &size);
 942         if (!data)
 943                 return NULL;
 944         if (type != OBJ_TREE) {
 945                 free(data);
 946                 return NULL;
 947         }
 948
 949         /* We need to either cache or return a throwaway copy */
 950
 951         if (available_ix < 0)
 952                 ent = NULL;
 953         else {
 954                 ent = pbase_tree_cache[available_ix];
 955                 my_ix = available_ix;
 956         }
 957
 958         if (!ent) {
 959                 nent = xmalloc(sizeof(*nent));
 960                 nent->temporary = (available_ix < 0);
 961         }
 962         else {
 963                 /* evict and reuse */
 964                 free(ent->tree_data);
 965                 nent = ent;
 966         }
 967         hashcpy(nent->sha1, sha1);
 968         nent->tree_data = data;
 969         nent->tree_size = size;
 970         nent->ref = 1;
 971         if (!nent->temporary)
 972                 pbase_tree_cache[my_ix] = nent;
 973         return nent;
 974 }
 975
 976 static void pbase_tree_put(struct pbase_tree_cache *cache)
 977 {
 978         if (!cache->temporary) {
 979                 cache->ref--;
 980                 return;
 981         }
 982         free(cache->tree_data);
 983         free(cache);
 984 }
 985
 986 static int name_cmp_len(const char *name)
 987 {
 988         int i;
 989         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 990                 ;
 991         return i;
 992 }
 993
 994 static void add_pbase_object(struct tree_desc *tree,
 995                              const char *name,
 996                              int cmplen,
 997                              const char *fullname)
 998 {
 999         struct name_entry entry;
1000         int cmp;
1001
1002         while (tree_entry(tree,&entry)) {
1003                 cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
1004                       memcmp(name, entry.path, cmplen);
1005                 if (cmp > 0)
1006                         continue;
1007                 if (cmp < 0)
1008                         return;
1009                 if (name[cmplen] != '/') {
1010                         unsigned hash = name_hash(fullname);
1011                         add_object_entry(entry.sha1, hash, 1);
1012                         return;
1013                 }
1014                 if (S_ISDIR(entry.mode)) {
1015                         struct tree_desc sub;
1016                         struct pbase_tree_cache *tree;
1017                         const char *down = name+cmplen+1;
1018                         int downlen = name_cmp_len(down);
1019
1020                         tree = pbase_tree_get(entry.sha1);
1021                         if (!tree)
1022                                 return;
1023                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1024
1025                         add_pbase_object(&sub, down, downlen, fullname);
1026                         pbase_tree_put(tree);
1027                 }
1028         }
1029 }
1030
1031 static unsigned *done_pbase_paths;
1032 static int done_pbase_paths_num;
1033 static int done_pbase_paths_alloc;
1034 static int done_pbase_path_pos(unsigned hash)
1035 {
1036         int lo = 0;
1037         int hi = done_pbase_paths_num;
1038         while (lo < hi) {
1039                 int mi = (hi + lo) / 2;
1040                 if (done_pbase_paths[mi] == hash)
1041                         return mi;
1042                 if (done_pbase_paths[mi] < hash)
1043                         hi = mi;
1044                 else
1045                         lo = mi + 1;
1046         }
1047         return -lo-1;
1048 }
1049
1050 static int check_pbase_path(unsigned hash)
1051 {
1052         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1053         if (0 <= pos)
1054                 return 1;
1055         pos = -pos - 1;
1056         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1057                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1058                 done_pbase_paths = xrealloc(done_pbase_paths,
1059                                             done_pbase_paths_alloc *
1060                                             sizeof(unsigned));
1061         }
1062         done_pbase_paths_num++;
1063         if (pos < done_pbase_paths_num)
1064                 memmove(done_pbase_paths + pos + 1,
1065                         done_pbase_paths + pos,
1066                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1067         done_pbase_paths[pos] = hash;
1068         return 0;
1069 }
1070
1071 static void add_preferred_base_object(const char *name, unsigned hash)
1072 {
1073         struct pbase_tree *it;
1074         int cmplen;
1075
1076         if (!num_preferred_base || check_pbase_path(hash))
1077                 return;
1078
1079         cmplen = name_cmp_len(name);
1080         for (it = pbase_tree; it; it = it->next) {
1081                 if (cmplen == 0) {
1082                         add_object_entry(it->pcache.sha1, 0, 1);
1083                 }
1084                 else {
1085                         struct tree_desc tree;
1086                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1087                         add_pbase_object(&tree, name, cmplen, name);
1088                 }
1089         }
1090 }
1091
1092 static void add_preferred_base(unsigned char *sha1)
1093 {
1094         struct pbase_tree *it;
1095         void *data;
1096         unsigned long size;
1097         unsigned char tree_sha1[20];
1098
1099         if (window <= num_preferred_base++)
1100                 return;
1101
1102         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1103         if (!data)
1104                 return;
1105
1106         for (it = pbase_tree; it; it = it->next) {
1107                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1108                         free(data);
1109                         return;
1110                 }
1111         }
1112
1113         it = xcalloc(1, sizeof(*it));
1114         it->next = pbase_tree;
1115         pbase_tree = it;
1116
1117         hashcpy(it->pcache.sha1, tree_sha1);
1118         it->pcache.tree_data = data;
1119         it->pcache.tree_size = size;
1120 }
1121
1122 static void check_object(struct object_entry *entry)
1123 {
1124         if (entry->in_pack && !entry->preferred_base) {
1125                 struct packed_git *p = entry->in_pack;
1126                 struct pack_window *w_curs = NULL;
1127                 unsigned long size, used;
1128                 unsigned int avail;
1129                 unsigned char *buf;
1130                 struct object_entry *base_entry = NULL;
1131
1132                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1133
1134                 /* We want in_pack_type even if we do not reuse delta.
1135                  * There is no point not reusing non-delta representations.
1136                  */
1137                 used = unpack_object_header_gently(buf, avail,
1138                                                    &entry->in_pack_type, &size);
1139
1140                 /* Check if it is delta, and the base is also an object
1141                  * we are going to pack.  If so we will reuse the existing
1142                  * delta.
1143                  */
1144                 if (!no_reuse_delta) {
1145                         unsigned char c;
1146                         const unsigned char *base_name;
1147                         off_t ofs;
1148                         unsigned long used_0;
1149                         /* there is at least 20 bytes left in the pack */
1150                         switch (entry->in_pack_type) {
1151                         case OBJ_REF_DELTA:
1152                                 base_name = use_pack(p, &w_curs,
1153                                         entry->in_pack_offset + used, NULL);
1154                                 used += 20;
1155                                 break;
1156                         case OBJ_OFS_DELTA:
1157                                 buf = use_pack(p, &w_curs,
1158                                         entry->in_pack_offset + used, NULL);
1159                                 used_0 = 0;
1160                                 c = buf[used_0++];
1161                                 ofs = c & 127;
1162                                 while (c & 128) {
1163                                         ofs += 1;
1164                                         if (!ofs || MSB(ofs, 7))
1165                                                 die("delta base offset overflow in pack for %s",
1166                                                     sha1_to_hex(entry->sha1));
1167                                         c = buf[used_0++];
1168                                         ofs = (ofs << 7) + (c & 127);
1169                                 }
1170                                 if (ofs >= entry->in_pack_offset)
1171                                         die("delta base offset out of bound for %s",
1172                                             sha1_to_hex(entry->sha1));
1173                                 ofs = entry->in_pack_offset - ofs;
1174                                 base_name = find_packed_object_name(p, ofs);
1175                                 used += used_0;
1176                                 break;
1177                         default:
1178                                 base_name = NULL;
1179                         }
1180                         if (base_name)
1181                                 base_entry = locate_object_entry(base_name);
1182                 }
1183                 unuse_pack(&w_curs);
1184                 entry->in_pack_header_size = used;
1185
1186                 if (base_entry) {
1187
1188                         /* Depth value does not matter - find_deltas()
1189                          * will never consider reused delta as the
1190                          * base object to deltify other objects
1191                          * against, in order to avoid circular deltas.
1192                          */
1193
1194                         /* uncompressed size of the delta data */
1195                         entry->size = size;
1196                         entry->delta = base_entry;
1197                         entry->type = entry->in_pack_type;
1198
1199                         entry->delta_sibling = base_entry->delta_child;
1200                         base_entry->delta_child = entry;
1201
1202                         return;
1203                 }
1204                 /* Otherwise we would do the usual */
1205         }
1206
1207         entry->type = sha1_object_info(entry->sha1, &entry->size);
1208         if (entry->type < 0)
1209                 die("unable to get type of object %s",
1210                     sha1_to_hex(entry->sha1));
1211 }
1212
1213 static void get_object_details(void)
1214 {
1215         uint32_t i;
1216         struct object_entry *entry;
1217
1218         prepare_pack_ix();
1219         for (i = 0, entry = objects; i < nr_objects; i++, entry++)
1220                 check_object(entry);
1221 }
1222
1223 static int type_size_sort(const void *_a, const void *_b)
1224 {
1225         const struct object_entry *a = *(struct object_entry **)_a;
1226         const struct object_entry *b = *(struct object_entry **)_b;
1227
1228         if (a->type < b->type)
1229                 return -1;
1230         if (a->type > b->type)
1231                 return 1;
1232         if (a->hash < b->hash)
1233                 return -1;
1234         if (a->hash > b->hash)
1235                 return 1;
1236         if (a->preferred_base < b->preferred_base)
1237                 return -1;
1238         if (a->preferred_base > b->preferred_base)
1239                 return 1;
1240         if (a->size < b->size)
1241                 return -1;
1242         if (a->size > b->size)
1243                 return 1;
1244         return a > b ? -1 : (a < b);  /* newest last */
1245 }
1246
1247 struct unpacked {
1248         struct object_entry *entry;
1249         void *data;
1250         struct delta_index *index;
1251 };
1252
1253 /*
1254  * We search for deltas _backwards_ in a list sorted by type and
1255  * by size, so that we see progressively smaller and smaller files.
1256  * That's because we prefer deltas to be from the bigger file
1257  * to the smaller - deletes are potentially cheaper, but perhaps
1258  * more importantly, the bigger file is likely the more recent
1259  * one.
1260  */
1261 static int try_delta(struct unpacked *trg, struct unpacked *src,
1262                      unsigned max_depth)
1263 {
1264         struct object_entry *trg_entry = trg->entry;
1265         struct object_entry *src_entry = src->entry;
1266         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1267         enum object_type type;
1268         void *delta_buf;
1269
1270         /* Don't bother doing diffs between different types */
1271         if (trg_entry->type != src_entry->type)
1272                 return -1;
1273
1274         /* We do not compute delta to *create* objects we are not
1275          * going to pack.
1276          */
1277         if (trg_entry->preferred_base)
1278                 return -1;
1279
1280         /*
1281          * We do not bother to try a delta that we discarded
1282          * on an earlier try, but only when reusing delta data.
1283          */
1284         if (!no_reuse_delta && trg_entry->in_pack &&
1285             trg_entry->in_pack == src_entry->in_pack &&
1286             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1287             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1288                 return 0;
1289
1290         /* Let's not bust the allowed depth. */
1291         if (src_entry->depth >= max_depth)
1292                 return 0;
1293
1294         /* Now some size filtering heuristics. */
1295         trg_size = trg_entry->size;
1296         max_size = trg_size/2 - 20;
1297         max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1298         if (max_size == 0)
1299                 return 0;
1300         if (trg_entry->delta && trg_entry->delta_size <= max_size)
1301                 max_size = trg_entry->delta_size-1;
1302         src_size = src_entry->size;
1303         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1304         if (sizediff >= max_size)
1305                 return 0;
1306
1307         /* Load data if not already done */
1308         if (!trg->data) {
1309                 trg->data = read_sha1_file(trg_entry->sha1, &type, &sz);
1310                 if (sz != trg_size)
1311                         die("object %s inconsistent object length (%lu vs %lu)",
1312                             sha1_to_hex(trg_entry->sha1), sz, trg_size);
1313         }
1314         if (!src->data) {
1315                 src->data = read_sha1_file(src_entry->sha1, &type, &sz);
1316                 if (sz != src_size)
1317                         die("object %s inconsistent object length (%lu vs %lu)",
1318                             sha1_to_hex(src_entry->sha1), sz, src_size);
1319         }
1320         if (!src->index) {
1321                 src->index = create_delta_index(src->data, src_size);
1322                 if (!src->index)
1323                         die("out of memory");
1324         }
1325
1326         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1327         if (!delta_buf)
1328                 return 0;
1329
1330         trg_entry->delta = src_entry;
1331         trg_entry->delta_size = delta_size;
1332         trg_entry->depth = src_entry->depth + 1;
1333         free(delta_buf);
1334         return 1;
1335 }
1336
1337 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1338 {
1339         struct object_entry *child = me->delta_child;
1340         unsigned int m = n;
1341         while (child) {
1342                 unsigned int c = check_delta_limit(child, n + 1);
1343                 if (m < c)
1344                         m = c;
1345                 child = child->delta_sibling;
1346         }
1347         return m;
1348 }
1349
1350 static void find_deltas(struct object_entry **list, int window, int depth)
1351 {
1352         uint32_t i = nr_objects, idx = 0, processed = 0;
1353         unsigned int array_size = window * sizeof(struct unpacked);
1354         struct unpacked *array;
1355         unsigned last_percent = 999;
1356         int max_depth;
1357
1358         if (!nr_objects)
1359                 return;
1360         array = xmalloc(array_size);
1361         memset(array, 0, array_size);
1362         if (progress)
1363                 fprintf(stderr, "Deltifying %u objects.\n", nr_result);
1364
1365         do {
1366                 struct object_entry *entry = list[--i];
1367                 struct unpacked *n = array + idx;
1368                 int j;
1369
1370                 if (!entry->preferred_base)
1371                         processed++;
1372
1373                 if (progress) {
1374                         unsigned percent = processed * 100 / nr_result;
1375                         if (percent != last_percent || progress_update) {
1376                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
1377                                         percent, processed, nr_result);
1378                                 progress_update = 0;
1379                                 last_percent = percent;
1380                         }
1381                 }
1382
1383                 if (entry->delta)
1384                         /* This happens if we decided to reuse existing
1385                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1386                          */
1387                         continue;
1388
1389                 if (entry->size < 50)
1390                         continue;
1391                 free_delta_index(n->index);
1392                 n->index = NULL;
1393                 free(n->data);
1394                 n->data = NULL;
1395                 n->entry = entry;
1396
1397                 /*
1398                  * If the current object is at pack edge, take the depth the
1399                  * objects that depend on the current object into account
1400                  * otherwise they would become too deep.
1401                  */
1402                 max_depth = depth;
1403                 if (entry->delta_child) {
1404                         max_depth -= check_delta_limit(entry, 0);
1405                         if (max_depth <= 0)
1406                                 goto next;
1407                 }
1408
1409                 j = window;
1410                 while (--j > 0) {
1411                         uint32_t other_idx = idx + j;
1412                         struct unpacked *m;
1413                         if (other_idx >= window)
1414                                 other_idx -= window;
1415                         m = array + other_idx;
1416                         if (!m->entry)
1417                                 break;
1418                         if (try_delta(n, m, max_depth) < 0)
1419                                 break;
1420                 }
1421
1422                 /* if we made n a delta, and if n is already at max
1423                  * depth, leaving it in the window is pointless.  we
1424                  * should evict it first.
1425                  */
1426                 if (entry->delta && depth <= entry->depth)
1427                         continue;
1428
1429                 next:
1430                 idx++;
1431                 if (idx >= window)
1432                         idx = 0;
1433         } while (i > 0);
1434
1435         if (progress)
1436                 fputc('\n', stderr);
1437
1438         for (i = 0; i < window; ++i) {
1439                 free_delta_index(array[i].index);
1440                 free(array[i].data);
1441         }
1442         free(array);
1443 }
1444
1445 static void prepare_pack(int window, int depth)
1446 {
1447         struct object_entry **delta_list;
1448         uint32_t i;
1449
1450         get_object_details();
1451
1452         if (!window || !depth)
1453                 return;
1454
1455         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1456         for (i = 0; i < nr_objects; i++)
1457                 delta_list[i] = objects + i;
1458         qsort(delta_list, nr_objects, sizeof(*delta_list), type_size_sort);
1459         find_deltas(delta_list, window+1, depth);
1460         free(delta_list);
1461 }
1462
1463 static void progress_interval(int signum)
1464 {
1465         progress_update = 1;
1466 }
1467
1468 static void setup_progress_signal(void)
1469 {
1470         struct sigaction sa;
1471         struct itimerval v;
1472
1473         memset(&sa, 0, sizeof(sa));
1474         sa.sa_handler = progress_interval;
1475         sigemptyset(&sa.sa_mask);
1476         sa.sa_flags = SA_RESTART;
1477         sigaction(SIGALRM, &sa, NULL);
1478
1479         v.it_interval.tv_sec = 1;
1480         v.it_interval.tv_usec = 0;
1481         v.it_value = v.it_interval;
1482         setitimer(ITIMER_REAL, &v, NULL);
1483 }
1484
1485 static int git_pack_config(const char *k, const char *v)
1486 {
1487         if(!strcmp(k, "pack.window")) {
1488                 window = git_config_int(k, v);
1489                 return 0;
1490         }
1491         return git_default_config(k, v);
1492 }
1493
1494 static void read_object_list_from_stdin(void)
1495 {
1496         char line[40 + 1 + PATH_MAX + 2];
1497         unsigned char sha1[20];
1498         unsigned hash;
1499
1500         for (;;) {
1501                 if (!fgets(line, sizeof(line), stdin)) {
1502                         if (feof(stdin))
1503                                 break;
1504                         if (!ferror(stdin))
1505                                 die("fgets returned NULL, not EOF, not error!");
1506                         if (errno != EINTR)
1507                                 die("fgets: %s", strerror(errno));
1508                         clearerr(stdin);
1509                         continue;
1510                 }
1511                 if (line[0] == '-') {
1512                         if (get_sha1_hex(line+1, sha1))
1513                                 die("expected edge sha1, got garbage:\n %s",
1514                                     line);
1515                         add_preferred_base(sha1);
1516                         continue;
1517                 }
1518                 if (get_sha1_hex(line, sha1))
1519                         die("expected sha1, got garbage:\n %s", line);
1520
1521                 hash = name_hash(line+41);
1522                 add_preferred_base_object(line+41, hash);
1523                 add_object_entry(sha1, hash, 0);
1524         }
1525 }
1526
1527 static void show_commit(struct commit *commit)
1528 {
1529         add_object_entry(commit->object.sha1, 0, 0);
1530 }
1531
1532 static void show_object(struct object_array_entry *p)
1533 {
1534         unsigned hash = name_hash(p->name);
1535         add_preferred_base_object(p->name, hash);
1536         add_object_entry(p->item->sha1, hash, 0);
1537 }
1538
1539 static void show_edge(struct commit *commit)
1540 {
1541         add_preferred_base(commit->object.sha1);
1542 }
1543
1544 static void get_object_list(int ac, const char **av)
1545 {
1546         struct rev_info revs;
1547         char line[1000];
1548         int flags = 0;
1549
1550         init_revisions(&revs, NULL);
1551         save_commit_buffer = 0;
1552         track_object_refs = 0;
1553         setup_revisions(ac, av, &revs, NULL);
1554
1555         while (fgets(line, sizeof(line), stdin) != NULL) {
1556                 int len = strlen(line);
1557                 if (line[len - 1] == '\n')
1558                         line[--len] = 0;
1559                 if (!len)
1560                         break;
1561                 if (*line == '-') {
1562                         if (!strcmp(line, "--not")) {
1563                                 flags ^= UNINTERESTING;
1564                                 continue;
1565                         }
1566                         die("not a rev '%s'", line);
1567                 }
1568                 if (handle_revision_arg(line, &revs, flags, 1))
1569                         die("bad revision '%s'", line);
1570         }
1571
1572         prepare_revision_walk(&revs);
1573         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1574         traverse_commit_list(&revs, show_commit, show_object);
1575 }
1576
1577 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1578 {
1579         int depth = 10;
1580         int use_internal_rev_list = 0;
1581         int thin = 0;
1582         uint32_t i;
1583         off_t last_obj_offset;
1584         const char *base_name = NULL;
1585         const char **rp_av;
1586         int rp_ac_alloc = 64;
1587         int rp_ac;
1588
1589         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1590
1591         rp_av[0] = "pack-objects";
1592         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1593         rp_ac = 2;
1594
1595         git_config(git_pack_config);
1596
1597         progress = isatty(2);
1598         for (i = 1; i < argc; i++) {
1599                 const char *arg = argv[i];
1600
1601                 if (*arg != '-')
1602                         break;
1603
1604                 if (!strcmp("--non-empty", arg)) {
1605                         non_empty = 1;
1606                         continue;
1607                 }
1608                 if (!strcmp("--local", arg)) {
1609                         local = 1;
1610                         continue;
1611                 }
1612                 if (!strcmp("--incremental", arg)) {
1613                         incremental = 1;
1614                         continue;
1615                 }
1616                 if (!prefixcmp(arg, "--window=")) {
1617                         char *end;
1618                         window = strtoul(arg+9, &end, 0);
1619                         if (!arg[9] || *end)
1620                                 usage(pack_usage);
1621                         continue;
1622                 }
1623                 if (!prefixcmp(arg, "--depth=")) {
1624                         char *end;
1625                         depth = strtoul(arg+8, &end, 0);
1626                         if (!arg[8] || *end)
1627                                 usage(pack_usage);
1628                         continue;
1629                 }
1630                 if (!strcmp("--progress", arg)) {
1631                         progress = 1;
1632                         continue;
1633                 }
1634                 if (!strcmp("--all-progress", arg)) {
1635                         progress = 2;
1636                         continue;
1637                 }
1638                 if (!strcmp("-q", arg)) {
1639                         progress = 0;
1640                         continue;
1641                 }
1642                 if (!strcmp("--no-reuse-delta", arg)) {
1643                         no_reuse_delta = 1;
1644                         continue;
1645                 }
1646                 if (!strcmp("--delta-base-offset", arg)) {
1647                         allow_ofs_delta = 1;
1648                         continue;
1649                 }
1650                 if (!strcmp("--stdout", arg)) {
1651                         pack_to_stdout = 1;
1652                         continue;
1653                 }
1654                 if (!strcmp("--revs", arg)) {
1655                         use_internal_rev_list = 1;
1656                         continue;
1657                 }
1658                 if (!strcmp("--unpacked", arg) ||
1659                     !prefixcmp(arg, "--unpacked=") ||
1660                     !strcmp("--reflog", arg) ||
1661                     !strcmp("--all", arg)) {
1662                         use_internal_rev_list = 1;
1663                         if (rp_ac >= rp_ac_alloc - 1) {
1664                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
1665                                 rp_av = xrealloc(rp_av,
1666                                                  rp_ac_alloc * sizeof(*rp_av));
1667                         }
1668                         rp_av[rp_ac++] = arg;
1669                         continue;
1670                 }
1671                 if (!strcmp("--thin", arg)) {
1672                         use_internal_rev_list = 1;
1673                         thin = 1;
1674                         rp_av[1] = "--objects-edge";
1675                         continue;
1676                 }
1677                 if (!prefixcmp(arg, "--index-version=")) {
1678                         char *c;
1679                         index_default_version = strtoul(arg + 16, &c, 10);
1680                         if (index_default_version > 2)
1681                                 die("bad %s", arg);
1682                         if (*c == ',')
1683                                 index_off32_limit = strtoul(c+1, &c, 0);
1684                         if (*c || index_off32_limit & 0x80000000)
1685                                 die("bad %s", arg);
1686                         continue;
1687                 }
1688                 usage(pack_usage);
1689         }
1690
1691         /* Traditionally "pack-objects [options] base extra" failed;
1692          * we would however want to take refs parameter that would
1693          * have been given to upstream rev-list ourselves, which means
1694          * we somehow want to say what the base name is.  So the
1695          * syntax would be:
1696          *
1697          * pack-objects [options] base <refs...>
1698          *
1699          * in other words, we would treat the first non-option as the
1700          * base_name and send everything else to the internal revision
1701          * walker.
1702          */
1703
1704         if (!pack_to_stdout)
1705                 base_name = argv[i++];
1706
1707         if (pack_to_stdout != !base_name)
1708                 usage(pack_usage);
1709
1710         if (!pack_to_stdout && thin)
1711                 die("--thin cannot be used to build an indexable pack.");
1712
1713         prepare_packed_git();
1714
1715         if (progress) {
1716                 fprintf(stderr, "Generating pack...\n");
1717                 setup_progress_signal();
1718         }
1719
1720         if (!use_internal_rev_list)
1721                 read_object_list_from_stdin();
1722         else {
1723                 rp_av[rp_ac] = NULL;
1724                 get_object_list(rp_ac, rp_av);
1725         }
1726
1727         if (progress)
1728                 fprintf(stderr, "Done counting %u objects.\n", nr_objects);
1729         if (non_empty && !nr_result)
1730                 return 0;
1731         if (progress && (nr_objects != nr_result))
1732                 fprintf(stderr, "Result has %u objects.\n", nr_result);
1733         if (nr_result)
1734                 prepare_pack(window, depth);
1735         if (progress == 1 && pack_to_stdout) {
1736                 /* the other end usually displays progress itself */
1737                 struct itimerval v = {{0,},};
1738                 setitimer(ITIMER_REAL, &v, NULL);
1739                 signal(SIGALRM, SIG_IGN );
1740                 progress_update = 0;
1741         }
1742         last_obj_offset = write_pack_file();
1743         if (!pack_to_stdout) {
1744                 unsigned char object_list_sha1[20];
1745                 write_index_file(last_obj_offset, object_list_sha1);
1746                 snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
1747                          base_name, sha1_to_hex(object_list_sha1));
1748                 if (rename(pack_tmp_name, tmpname))
1749                         die("unable to rename temporary pack file: %s",
1750                             strerror(errno));
1751                 snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
1752                          base_name, sha1_to_hex(object_list_sha1));
1753                 if (rename(idx_tmp_name, tmpname))
1754                         die("unable to rename temporary index file: %s",
1755                             strerror(errno));
1756                 puts(sha1_to_hex(object_list_sha1));
1757         }
1758         if (progress)
1759                 fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
1760                         written, written_delta, reused, reused_delta);
1761         return 0;
1762 }