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         unsigned long size;     /* uncompressed size */
  26         off_t offset;   /* offset into the final pack file;
  27                                  * nonzero if already written.
  28                                  */
  29         unsigned int depth;     /* delta depth */
  30         unsigned int delta_limit;       /* base adjustment for in-pack delta */
  31         unsigned int hash;      /* name hint hash */
  32         enum object_type type;
  33         enum object_type in_pack_type;  /* could be delta */
  34         unsigned long delta_size;       /* delta data size (uncompressed) */
  35 #define in_pack_header_size delta_size  /* only when reusing pack data */
  36         struct object_entry *delta;     /* delta base object */
  37         struct packed_git *in_pack;     /* already in pack */
  38         off_t in_pack_offset;
  39         struct object_entry *delta_child; /* deltified objects who bases me */
  40         struct object_entry *delta_sibling; /* other deltified objects who
  41                                              * uses the same base as me
  42                                              */
  43         int preferred_base;     /* we do not pack this, but is encouraged to
  44                                  * be used as the base objectto delta huge
  45                                  * objects against.
  46                                  */
  47 };
  48
  49 /*
  50  * Objects we are going to pack are collected in objects array (dynamically
  51  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  52  * in the order we see -- typically rev-list --objects order that gives us
  53  * nice "minimum seek" order.
  54  *
  55  * sorted-by-sha ans sorted-by-type are arrays of pointers that point at
  56  * elements in the objects array.  The former is used to build the pack
  57  * index (lists object names in the ascending order to help offset lookup),
  58  * and the latter is used to group similar things together by try_delta()
  59  * heuristics.
  60  */
  61
  62 static unsigned char object_list_sha1[20];
  63 static int non_empty;
  64 static int no_reuse_delta;
  65 static int local;
  66 static int incremental;
  67 static int allow_ofs_delta;
  68
  69 static struct object_entry **sorted_by_sha, **sorted_by_type;
  70 static struct object_entry *objects;
  71 static uint32_t nr_objects, nr_alloc, nr_result;
  72 static const char *base_name;
  73 static unsigned char pack_file_sha1[20];
  74 static int progress = 1;
  75 static volatile sig_atomic_t progress_update;
  76 static int window = 10;
  77 static int pack_to_stdout;
  78 static int num_preferred_base;
  79
  80 /*
  81  * The object names in objects array are hashed with this hashtable,
  82  * to help looking up the entry by object name.  Binary search from
  83  * sorted_by_sha is also possible but this was easier to code and faster.
  84  * This hashtable is built after all the objects are seen.
  85  */
  86 static int *object_ix;
  87 static int object_ix_hashsz;
  88
  89 /*
  90  * Pack index for existing packs give us easy access to the offsets into
  91  * corresponding pack file where each object's data starts, but the entries
  92  * do not store the size of the compressed representation (uncompressed
  93  * size is easily available by examining the pack entry header).  It is
  94  * also rather expensive to find the sha1 for an object given its offset.
  95  *
  96  * We build a hashtable of existing packs (pack_revindex), and keep reverse
  97  * index here -- pack index file is sorted by object name mapping to offset;
  98  * this pack_revindex[].revindex array is a list of offset/index_nr pairs
  99  * ordered by offset, so if you know the offset of an object, next offset
 100  * is where its packed representation ends and the index_nr can be used to
 101  * get the object sha1 from the main index.
 102  */
 103 struct revindex_entry {
 104         off_t offset;
 105         unsigned int nr;
 106 };
 107 struct pack_revindex {
 108         struct packed_git *p;
 109         struct revindex_entry *revindex;
 110 };
 111 static struct  pack_revindex *pack_revindex;
 112 static int pack_revindex_hashsz;
 113
 114 /*
 115  * stats
 116  */
 117 static uint32_t written, written_delta;
 118 static uint32_t reused, reused_delta;
 119
 120 static int pack_revindex_ix(struct packed_git *p)
 121 {
 122         unsigned long ui = (unsigned long)p;
 123         int i;
 124
 125         ui = ui ^ (ui >> 16); /* defeat structure alignment */
 126         i = (int)(ui % pack_revindex_hashsz);
 127         while (pack_revindex[i].p) {
 128                 if (pack_revindex[i].p == p)
 129                         return i;
 130                 if (++i == pack_revindex_hashsz)
 131                         i = 0;
 132         }
 133         return -1 - i;
 134 }
 135
 136 static void prepare_pack_ix(void)
 137 {
 138         int num;
 139         struct packed_git *p;
 140         for (num = 0, p = packed_git; p; p = p->next)
 141                 num++;
 142         if (!num)
 143                 return;
 144         pack_revindex_hashsz = num * 11;
 145         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 146         for (p = packed_git; p; p = p->next) {
 147                 num = pack_revindex_ix(p);
 148                 num = - 1 - num;
 149                 pack_revindex[num].p = p;
 150         }
 151         /* revindex elements are lazily initialized */
 152 }
 153
 154 static int cmp_offset(const void *a_, const void *b_)
 155 {
 156         const struct revindex_entry *a = a_;
 157         const struct revindex_entry *b = b_;
 158         return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
 159 }
 160
 161 /*
 162  * Ordered list of offsets of objects in the pack.
 163  */
 164 static void prepare_pack_revindex(struct pack_revindex *rix)
 165 {
 166         struct packed_git *p = rix->p;
 167         int num_ent = p->num_objects;
 168         int i;
 169         const char *index = p->index_data;
 170
 171         index += 4 * 256;
 172         rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
 173         for (i = 0; i < num_ent; i++) {
 174                 uint32_t hl = *((uint32_t *)(index + 24 * i));
 175                 rix->revindex[i].offset = ntohl(hl);
 176                 rix->revindex[i].nr = i;
 177         }
 178         /* This knows the pack format -- the 20-byte trailer
 179          * follows immediately after the last object data.
 180          */
 181         rix->revindex[num_ent].offset = p->pack_size - 20;
 182         rix->revindex[num_ent].nr = -1;
 183         qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
 184 }
 185
 186 static struct revindex_entry * find_packed_object(struct packed_git *p,
 187                                                   off_t ofs)
 188 {
 189         int num;
 190         int lo, hi;
 191         struct pack_revindex *rix;
 192         struct revindex_entry *revindex;
 193         num = pack_revindex_ix(p);
 194         if (num < 0)
 195                 die("internal error: pack revindex uninitialized");
 196         rix = &pack_revindex[num];
 197         if (!rix->revindex)
 198                 prepare_pack_revindex(rix);
 199         revindex = rix->revindex;
 200         lo = 0;
 201         hi = p->num_objects + 1;
 202         do {
 203                 int mi = (lo + hi) / 2;
 204                 if (revindex[mi].offset == ofs) {
 205                         return revindex + mi;
 206                 }
 207                 else if (ofs < revindex[mi].offset)
 208                         hi = mi;
 209                 else
 210                         lo = mi + 1;
 211         } while (lo < hi);
 212         die("internal error: pack revindex corrupt");
 213 }
 214
 215 static off_t find_packed_object_size(struct packed_git *p, off_t ofs)
 216 {
 217         struct revindex_entry *entry = find_packed_object(p, ofs);
 218         return entry[1].offset - ofs;
 219 }
 220
 221 static const unsigned char *find_packed_object_name(struct packed_git *p,
 222                                                     off_t ofs)
 223 {
 224         struct revindex_entry *entry = find_packed_object(p, ofs);
 225         return nth_packed_object_sha1(p, entry->nr);
 226 }
 227
 228 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 229 {
 230         unsigned long othersize, delta_size;
 231         enum object_type type;
 232         void *otherbuf = read_sha1_file(entry->delta->sha1, &type, &othersize);
 233         void *delta_buf;
 234
 235         if (!otherbuf)
 236                 die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 237         delta_buf = diff_delta(otherbuf, othersize,
 238                                buf, size, &delta_size, 0);
 239         if (!delta_buf || delta_size != entry->delta_size)
 240                 die("delta size changed");
 241         free(buf);
 242         free(otherbuf);
 243         return delta_buf;
 244 }
 245
 246 /*
 247  * The per-object header is a pretty dense thing, which is
 248  *  - first byte: low four bits are "size", then three bits of "type",
 249  *    and the high bit is "size continues".
 250  *  - each byte afterwards: low seven bits are size continuation,
 251  *    with the high bit being "size continues"
 252  */
 253 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 254 {
 255         int n = 1;
 256         unsigned char c;
 257
 258         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 259                 die("bad type %d", type);
 260
 261         c = (type << 4) | (size & 15);
 262         size >>= 4;
 263         while (size) {
 264                 *hdr++ = c | 0x80;
 265                 c = size & 0x7f;
 266                 size >>= 7;
 267                 n++;
 268         }
 269         *hdr = c;
 270         return n;
 271 }
 272
 273 /*
 274  * we are going to reuse the existing object data as is.  make
 275  * sure it is not corrupt.
 276  */
 277 static int check_pack_inflate(struct packed_git *p,
 278                 struct pack_window **w_curs,
 279                 off_t offset,
 280                 off_t len,
 281                 unsigned long expect)
 282 {
 283         z_stream stream;
 284         unsigned char fakebuf[4096], *in;
 285         int st;
 286
 287         memset(&stream, 0, sizeof(stream));
 288         inflateInit(&stream);
 289         do {
 290                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 291                 stream.next_in = in;
 292                 stream.next_out = fakebuf;
 293                 stream.avail_out = sizeof(fakebuf);
 294                 st = inflate(&stream, Z_FINISH);
 295                 offset += stream.next_in - in;
 296         } while (st == Z_OK || st == Z_BUF_ERROR);
 297         inflateEnd(&stream);
 298         return (st == Z_STREAM_END &&
 299                 stream.total_out == expect &&
 300                 stream.total_in == len) ? 0 : -1;
 301 }
 302
 303 static void copy_pack_data(struct sha1file *f,
 304                 struct packed_git *p,
 305                 struct pack_window **w_curs,
 306                 off_t offset,
 307                 off_t len)
 308 {
 309         unsigned char *in;
 310         unsigned int avail;
 311
 312         while (len) {
 313                 in = use_pack(p, w_curs, offset, &avail);
 314                 if (avail > len)
 315                         avail = (unsigned int)len;
 316                 sha1write(f, in, avail);
 317                 offset += avail;
 318                 len -= avail;
 319         }
 320 }
 321
 322 static int check_loose_inflate(unsigned char *data, unsigned long len, unsigned long expect)
 323 {
 324         z_stream stream;
 325         unsigned char fakebuf[4096];
 326         int st;
 327
 328         memset(&stream, 0, sizeof(stream));
 329         stream.next_in = data;
 330         stream.avail_in = len;
 331         stream.next_out = fakebuf;
 332         stream.avail_out = sizeof(fakebuf);
 333         inflateInit(&stream);
 334
 335         while (1) {
 336                 st = inflate(&stream, Z_FINISH);
 337                 if (st == Z_STREAM_END || st == Z_OK) {
 338                         st = (stream.total_out == expect &&
 339                               stream.total_in == len) ? 0 : -1;
 340                         break;
 341                 }
 342                 if (st != Z_BUF_ERROR) {
 343                         st = -1;
 344                         break;
 345                 }
 346                 stream.next_out = fakebuf;
 347                 stream.avail_out = sizeof(fakebuf);
 348         }
 349         inflateEnd(&stream);
 350         return st;
 351 }
 352
 353 static int revalidate_loose_object(struct object_entry *entry,
 354                                    unsigned char *map,
 355                                    unsigned long mapsize)
 356 {
 357         /* we already know this is a loose object with new type header. */
 358         enum object_type type;
 359         unsigned long size, used;
 360
 361         if (pack_to_stdout)
 362                 return 0;
 363
 364         used = unpack_object_header_gently(map, mapsize, &type, &size);
 365         if (!used)
 366                 return -1;
 367         map += used;
 368         mapsize -= used;
 369         return check_loose_inflate(map, mapsize, size);
 370 }
 371
 372 static unsigned long write_object(struct sha1file *f,
 373                                   struct object_entry *entry)
 374 {
 375         unsigned long size;
 376         enum object_type type;
 377         void *buf;
 378         unsigned char header[10];
 379         unsigned hdrlen;
 380         off_t datalen;
 381         enum object_type obj_type;
 382         int to_reuse = 0;
 383
 384         obj_type = entry->type;
 385         if (! entry->in_pack)
 386                 to_reuse = 0;   /* can't reuse what we don't have */
 387         else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 388                 to_reuse = 1;   /* check_object() decided it for us */
 389         else if (obj_type != entry->in_pack_type)
 390                 to_reuse = 0;   /* pack has delta which is unusable */
 391         else if (entry->delta)
 392                 to_reuse = 0;   /* we want to pack afresh */
 393         else
 394                 to_reuse = 1;   /* we have it in-pack undeltified,
 395                                  * and we do not need to deltify it.
 396                                  */
 397
 398         if (!entry->in_pack && !entry->delta) {
 399                 unsigned char *map;
 400                 unsigned long mapsize;
 401                 map = map_sha1_file(entry->sha1, &mapsize);
 402                 if (map && !legacy_loose_object(map)) {
 403                         /* We can copy straight into the pack file */
 404                         if (revalidate_loose_object(entry, map, mapsize))
 405                                 die("corrupt loose object %s",
 406                                     sha1_to_hex(entry->sha1));
 407                         sha1write(f, map, mapsize);
 408                         munmap(map, mapsize);
 409                         written++;
 410                         reused++;
 411                         return mapsize;
 412                 }
 413                 if (map)
 414                         munmap(map, mapsize);
 415         }
 416
 417         if (!to_reuse) {
 418                 buf = read_sha1_file(entry->sha1, &type, &size);
 419                 if (!buf)
 420                         die("unable to read %s", sha1_to_hex(entry->sha1));
 421                 if (size != entry->size)
 422                         die("object %s size inconsistency (%lu vs %lu)",
 423                             sha1_to_hex(entry->sha1), size, entry->size);
 424                 if (entry->delta) {
 425                         buf = delta_against(buf, size, entry);
 426                         size = entry->delta_size;
 427                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 428                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 429                 }
 430                 /*
 431                  * The object header is a byte of 'type' followed by zero or
 432                  * more bytes of length.
 433                  */
 434                 hdrlen = encode_header(obj_type, size, header);
 435                 sha1write(f, header, hdrlen);
 436
 437                 if (obj_type == OBJ_OFS_DELTA) {
 438                         /*
 439                          * Deltas with relative base contain an additional
 440                          * encoding of the relative offset for the delta
 441                          * base from this object's position in the pack.
 442                          */
 443                         off_t ofs = entry->offset - entry->delta->offset;
 444                         unsigned pos = sizeof(header) - 1;
 445                         header[pos] = ofs & 127;
 446                         while (ofs >>= 7)
 447                                 header[--pos] = 128 | (--ofs & 127);
 448                         sha1write(f, header + pos, sizeof(header) - pos);
 449                         hdrlen += sizeof(header) - pos;
 450                 } else if (obj_type == OBJ_REF_DELTA) {
 451                         /*
 452                          * Deltas with a base reference contain
 453                          * an additional 20 bytes for the base sha1.
 454                          */
 455                         sha1write(f, entry->delta->sha1, 20);
 456                         hdrlen += 20;
 457                 }
 458                 datalen = sha1write_compressed(f, buf, size);
 459                 free(buf);
 460         }
 461         else {
 462                 struct packed_git *p = entry->in_pack;
 463                 struct pack_window *w_curs = NULL;
 464                 off_t offset;
 465
 466                 if (entry->delta) {
 467                         obj_type = (allow_ofs_delta && entry->delta->offset) ?
 468                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 469                         reused_delta++;
 470                 }
 471                 hdrlen = encode_header(obj_type, entry->size, header);
 472                 sha1write(f, header, hdrlen);
 473                 if (obj_type == OBJ_OFS_DELTA) {
 474                         off_t ofs = entry->offset - entry->delta->offset;
 475                         unsigned pos = sizeof(header) - 1;
 476                         header[pos] = ofs & 127;
 477                         while (ofs >>= 7)
 478                                 header[--pos] = 128 | (--ofs & 127);
 479                         sha1write(f, header + pos, sizeof(header) - pos);
 480                         hdrlen += sizeof(header) - pos;
 481                 } else if (obj_type == OBJ_REF_DELTA) {
 482                         sha1write(f, entry->delta->sha1, 20);
 483                         hdrlen += 20;
 484                 }
 485
 486                 offset = entry->in_pack_offset + entry->in_pack_header_size;
 487                 datalen = find_packed_object_size(p, entry->in_pack_offset)
 488                                 - entry->in_pack_header_size;
 489                 if (!pack_to_stdout && check_pack_inflate(p, &w_curs,
 490                                 offset, datalen, entry->size))
 491                         die("corrupt delta in pack %s", sha1_to_hex(entry->sha1));
 492                 copy_pack_data(f, p, &w_curs, offset, datalen);
 493                 unuse_pack(&w_curs);
 494                 reused++;
 495         }
 496         if (entry->delta)
 497                 written_delta++;
 498         written++;
 499         return hdrlen + datalen;
 500 }
 501
 502 static off_t write_one(struct sha1file *f,
 503                                struct object_entry *e,
 504                                off_t offset)
 505 {
 506         unsigned long size;
 507
 508         /* offset is non zero if object is written already. */
 509         if (e->offset || e->preferred_base)
 510                 return offset;
 511
 512         /* if we are deltified, write out base object first. */
 513         if (e->delta)
 514                 offset = write_one(f, e->delta, offset);
 515
 516         e->offset = offset;
 517         size = write_object(f, e);
 518
 519         /* make sure off_t is sufficiently large not to wrap */
 520         if (offset > offset + size)
 521                 die("pack too large for current definition of off_t");
 522         return offset + size;
 523 }
 524
 525 static void write_pack_file(void)
 526 {
 527         uint32_t i;
 528         struct sha1file *f;
 529         off_t offset;
 530         struct pack_header hdr;
 531         unsigned last_percent = 999;
 532         int do_progress = progress;
 533
 534         if (!base_name) {
 535                 f = sha1fd(1, "<stdout>");
 536                 do_progress >>= 1;
 537         }
 538         else
 539                 f = sha1create("%s-%s.%s", base_name,
 540                                sha1_to_hex(object_list_sha1), "pack");
 541         if (do_progress)
 542                 fprintf(stderr, "Writing %u objects.\n", nr_result);
 543
 544         hdr.hdr_signature = htonl(PACK_SIGNATURE);
 545         hdr.hdr_version = htonl(PACK_VERSION);
 546         hdr.hdr_entries = htonl(nr_result);
 547         sha1write(f, &hdr, sizeof(hdr));
 548         offset = sizeof(hdr);
 549         if (!nr_result)
 550                 goto done;
 551         for (i = 0; i < nr_objects; i++) {
 552                 offset = write_one(f, objects + i, offset);
 553                 if (do_progress) {
 554                         unsigned percent = written * 100 / nr_result;
 555                         if (progress_update || percent != last_percent) {
 556                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
 557                                         percent, written, nr_result);
 558                                 progress_update = 0;
 559                                 last_percent = percent;
 560                         }
 561                 }
 562         }
 563         if (do_progress)
 564                 fputc('\n', stderr);
 565  done:
 566         if (written != nr_result)
 567                 die("wrote %u objects while expecting %u", written, nr_result);
 568         sha1close(f, pack_file_sha1, 1);
 569 }
 570
 571 static void write_index_file(void)
 572 {
 573         uint32_t i;
 574         struct sha1file *f = sha1create("%s-%s.%s", base_name,
 575                                         sha1_to_hex(object_list_sha1), "idx");
 576         struct object_entry **list = sorted_by_sha;
 577         struct object_entry **last = list + nr_result;
 578         uint32_t array[256];
 579
 580         /*
 581          * Write the first-level table (the list is sorted,
 582          * but we use a 256-entry lookup to be able to avoid
 583          * having to do eight extra binary search iterations).
 584          */
 585         for (i = 0; i < 256; i++) {
 586                 struct object_entry **next = list;
 587                 while (next < last) {
 588                         struct object_entry *entry = *next;
 589                         if (entry->sha1[0] != i)
 590                                 break;
 591                         next++;
 592                 }
 593                 array[i] = htonl(next - sorted_by_sha);
 594                 list = next;
 595         }
 596         sha1write(f, array, 256 * 4);
 597
 598         /*
 599          * Write the actual SHA1 entries..
 600          */
 601         list = sorted_by_sha;
 602         for (i = 0; i < nr_result; i++) {
 603                 struct object_entry *entry = *list++;
 604                 uint32_t offset = htonl(entry->offset);
 605                 sha1write(f, &offset, 4);
 606                 sha1write(f, entry->sha1, 20);
 607         }
 608         sha1write(f, pack_file_sha1, 20);
 609         sha1close(f, NULL, 1);
 610 }
 611
 612 static int locate_object_entry_hash(const unsigned char *sha1)
 613 {
 614         int i;
 615         unsigned int ui;
 616         memcpy(&ui, sha1, sizeof(unsigned int));
 617         i = ui % object_ix_hashsz;
 618         while (0 < object_ix[i]) {
 619                 if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
 620                         return i;
 621                 if (++i == object_ix_hashsz)
 622                         i = 0;
 623         }
 624         return -1 - i;
 625 }
 626
 627 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 628 {
 629         int i;
 630
 631         if (!object_ix_hashsz)
 632                 return NULL;
 633
 634         i = locate_object_entry_hash(sha1);
 635         if (0 <= i)
 636                 return &objects[object_ix[i]-1];
 637         return NULL;
 638 }
 639
 640 static void rehash_objects(void)
 641 {
 642         uint32_t i;
 643         struct object_entry *oe;
 644
 645         object_ix_hashsz = nr_objects * 3;
 646         if (object_ix_hashsz < 1024)
 647                 object_ix_hashsz = 1024;
 648         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 649         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 650         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 651                 int ix = locate_object_entry_hash(oe->sha1);
 652                 if (0 <= ix)
 653                         continue;
 654                 ix = -1 - ix;
 655                 object_ix[ix] = i + 1;
 656         }
 657 }
 658
 659 static unsigned name_hash(const char *name)
 660 {
 661         unsigned char c;
 662         unsigned hash = 0;
 663
 664         /*
 665          * This effectively just creates a sortable number from the
 666          * last sixteen non-whitespace characters. Last characters
 667          * count "most", so things that end in ".c" sort together.
 668          */
 669         while ((c = *name++) != 0) {
 670                 if (isspace(c))
 671                         continue;
 672                 hash = (hash >> 2) + (c << 24);
 673         }
 674         return hash;
 675 }
 676
 677 static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude)
 678 {
 679         uint32_t idx = nr_objects;
 680         struct object_entry *entry;
 681         struct packed_git *p;
 682         off_t found_offset = 0;
 683         struct packed_git *found_pack = NULL;
 684         int ix, status = 0;
 685
 686         if (!exclude) {
 687                 for (p = packed_git; p; p = p->next) {
 688                         off_t offset = find_pack_entry_one(sha1, p);
 689                         if (offset) {
 690                                 if (incremental)
 691                                         return 0;
 692                                 if (local && !p->pack_local)
 693                                         return 0;
 694                                 if (!found_pack) {
 695                                         found_offset = offset;
 696                                         found_pack = p;
 697                                 }
 698                         }
 699                 }
 700         }
 701         if ((entry = locate_object_entry(sha1)) != NULL)
 702                 goto already_added;
 703
 704         if (idx >= nr_alloc) {
 705                 nr_alloc = (idx + 1024) * 3 / 2;
 706                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 707         }
 708         entry = objects + idx;
 709         nr_objects = idx + 1;
 710         memset(entry, 0, sizeof(*entry));
 711         hashcpy(entry->sha1, sha1);
 712         entry->hash = hash;
 713
 714         if (object_ix_hashsz * 3 <= nr_objects * 4)
 715                 rehash_objects();
 716         else {
 717                 ix = locate_object_entry_hash(entry->sha1);
 718                 if (0 <= ix)
 719                         die("internal error in object hashing.");
 720                 object_ix[-1 - ix] = idx + 1;
 721         }
 722         status = 1;
 723
 724  already_added:
 725         if (progress_update) {
 726                 fprintf(stderr, "Counting objects...%u\r", nr_objects);
 727                 progress_update = 0;
 728         }
 729         if (exclude)
 730                 entry->preferred_base = 1;
 731         else {
 732                 if (found_pack) {
 733                         entry->in_pack = found_pack;
 734                         entry->in_pack_offset = found_offset;
 735                 }
 736         }
 737         return status;
 738 }
 739
 740 struct pbase_tree_cache {
 741         unsigned char sha1[20];
 742         int ref;
 743         int temporary;
 744         void *tree_data;
 745         unsigned long tree_size;
 746 };
 747
 748 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 749 static int pbase_tree_cache_ix(const unsigned char *sha1)
 750 {
 751         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 752 }
 753 static int pbase_tree_cache_ix_incr(int ix)
 754 {
 755         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 756 }
 757
 758 static struct pbase_tree {
 759         struct pbase_tree *next;
 760         /* This is a phony "cache" entry; we are not
 761          * going to evict it nor find it through _get()
 762          * mechanism -- this is for the toplevel node that
 763          * would almost always change with any commit.
 764          */
 765         struct pbase_tree_cache pcache;
 766 } *pbase_tree;
 767
 768 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 769 {
 770         struct pbase_tree_cache *ent, *nent;
 771         void *data;
 772         unsigned long size;
 773         enum object_type type;
 774         int neigh;
 775         int my_ix = pbase_tree_cache_ix(sha1);
 776         int available_ix = -1;
 777
 778         /* pbase-tree-cache acts as a limited hashtable.
 779          * your object will be found at your index or within a few
 780          * slots after that slot if it is cached.
 781          */
 782         for (neigh = 0; neigh < 8; neigh++) {
 783                 ent = pbase_tree_cache[my_ix];
 784                 if (ent && !hashcmp(ent->sha1, sha1)) {
 785                         ent->ref++;
 786                         return ent;
 787                 }
 788                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 789                          ((0 <= available_ix) &&
 790                           (!ent && pbase_tree_cache[available_ix])))
 791                         available_ix = my_ix;
 792                 if (!ent)
 793                         break;
 794                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 795         }
 796
 797         /* Did not find one.  Either we got a bogus request or
 798          * we need to read and perhaps cache.
 799          */
 800         data = read_sha1_file(sha1, &type, &size);
 801         if (!data)
 802                 return NULL;
 803         if (type != OBJ_TREE) {
 804                 free(data);
 805                 return NULL;
 806         }
 807
 808         /* We need to either cache or return a throwaway copy */
 809
 810         if (available_ix < 0)
 811                 ent = NULL;
 812         else {
 813                 ent = pbase_tree_cache[available_ix];
 814                 my_ix = available_ix;
 815         }
 816
 817         if (!ent) {
 818                 nent = xmalloc(sizeof(*nent));
 819                 nent->temporary = (available_ix < 0);
 820         }
 821         else {
 822                 /* evict and reuse */
 823                 free(ent->tree_data);
 824                 nent = ent;
 825         }
 826         hashcpy(nent->sha1, sha1);
 827         nent->tree_data = data;
 828         nent->tree_size = size;
 829         nent->ref = 1;
 830         if (!nent->temporary)
 831                 pbase_tree_cache[my_ix] = nent;
 832         return nent;
 833 }
 834
 835 static void pbase_tree_put(struct pbase_tree_cache *cache)
 836 {
 837         if (!cache->temporary) {
 838                 cache->ref--;
 839                 return;
 840         }
 841         free(cache->tree_data);
 842         free(cache);
 843 }
 844
 845 static int name_cmp_len(const char *name)
 846 {
 847         int i;
 848         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 849                 ;
 850         return i;
 851 }
 852
 853 static void add_pbase_object(struct tree_desc *tree,
 854                              const char *name,
 855                              int cmplen,
 856                              const char *fullname)
 857 {
 858         struct name_entry entry;
 859
 860         while (tree_entry(tree,&entry)) {
 861                 unsigned long size;
 862                 enum object_type type;
 863
 864                 if (tree_entry_len(entry.path, entry.sha1) != cmplen ||
 865                     memcmp(entry.path, name, cmplen) ||
 866                     !has_sha1_file(entry.sha1) ||
 867                     (type = sha1_object_info(entry.sha1, &size)) < 0)
 868                         continue;
 869                 if (name[cmplen] != '/') {
 870                         unsigned hash = name_hash(fullname);
 871                         add_object_entry(entry.sha1, hash, 1);
 872                         return;
 873                 }
 874                 if (type == OBJ_TREE) {
 875                         struct tree_desc sub;
 876                         struct pbase_tree_cache *tree;
 877                         const char *down = name+cmplen+1;
 878                         int downlen = name_cmp_len(down);
 879
 880                         tree = pbase_tree_get(entry.sha1);
 881                         if (!tree)
 882                                 return;
 883                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
 884
 885                         add_pbase_object(&sub, down, downlen, fullname);
 886                         pbase_tree_put(tree);
 887                 }
 888         }
 889 }
 890
 891 static unsigned *done_pbase_paths;
 892 static int done_pbase_paths_num;
 893 static int done_pbase_paths_alloc;
 894 static int done_pbase_path_pos(unsigned hash)
 895 {
 896         int lo = 0;
 897         int hi = done_pbase_paths_num;
 898         while (lo < hi) {
 899                 int mi = (hi + lo) / 2;
 900                 if (done_pbase_paths[mi] == hash)
 901                         return mi;
 902                 if (done_pbase_paths[mi] < hash)
 903                         hi = mi;
 904                 else
 905                         lo = mi + 1;
 906         }
 907         return -lo-1;
 908 }
 909
 910 static int check_pbase_path(unsigned hash)
 911 {
 912         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 913         if (0 <= pos)
 914                 return 1;
 915         pos = -pos - 1;
 916         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 917                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 918                 done_pbase_paths = xrealloc(done_pbase_paths,
 919                                             done_pbase_paths_alloc *
 920                                             sizeof(unsigned));
 921         }
 922         done_pbase_paths_num++;
 923         if (pos < done_pbase_paths_num)
 924                 memmove(done_pbase_paths + pos + 1,
 925                         done_pbase_paths + pos,
 926                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 927         done_pbase_paths[pos] = hash;
 928         return 0;
 929 }
 930
 931 static void add_preferred_base_object(const char *name, unsigned hash)
 932 {
 933         struct pbase_tree *it;
 934         int cmplen = name_cmp_len(name);
 935
 936         if (check_pbase_path(hash))
 937                 return;
 938
 939         for (it = pbase_tree; it; it = it->next) {
 940                 if (cmplen == 0) {
 941                         hash = name_hash("");
 942                         add_object_entry(it->pcache.sha1, hash, 1);
 943                 }
 944                 else {
 945                         struct tree_desc tree;
 946                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
 947                         add_pbase_object(&tree, name, cmplen, name);
 948                 }
 949         }
 950 }
 951
 952 static void add_preferred_base(unsigned char *sha1)
 953 {
 954         struct pbase_tree *it;
 955         void *data;
 956         unsigned long size;
 957         unsigned char tree_sha1[20];
 958
 959         if (window <= num_preferred_base++)
 960                 return;
 961
 962         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 963         if (!data)
 964                 return;
 965
 966         for (it = pbase_tree; it; it = it->next) {
 967                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
 968                         free(data);
 969                         return;
 970                 }
 971         }
 972
 973         it = xcalloc(1, sizeof(*it));
 974         it->next = pbase_tree;
 975         pbase_tree = it;
 976
 977         hashcpy(it->pcache.sha1, tree_sha1);
 978         it->pcache.tree_data = data;
 979         it->pcache.tree_size = size;
 980 }
 981
 982 static void check_object(struct object_entry *entry)
 983 {
 984         if (entry->in_pack && !entry->preferred_base) {
 985                 struct packed_git *p = entry->in_pack;
 986                 struct pack_window *w_curs = NULL;
 987                 unsigned long size, used;
 988                 unsigned int avail;
 989                 unsigned char *buf;
 990                 struct object_entry *base_entry = NULL;
 991
 992                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
 993
 994                 /* We want in_pack_type even if we do not reuse delta.
 995                  * There is no point not reusing non-delta representations.
 996                  */
 997                 used = unpack_object_header_gently(buf, avail,
 998                                                    &entry->in_pack_type, &size);
 999
1000                 /* Check if it is delta, and the base is also an object
1001                  * we are going to pack.  If so we will reuse the existing
1002                  * delta.
1003                  */
1004                 if (!no_reuse_delta) {
1005                         unsigned char c;
1006                         const unsigned char *base_name;
1007                         off_t ofs;
1008                         unsigned long used_0;
1009                         /* there is at least 20 bytes left in the pack */
1010                         switch (entry->in_pack_type) {
1011                         case OBJ_REF_DELTA:
1012                                 base_name = use_pack(p, &w_curs,
1013                                         entry->in_pack_offset + used, NULL);
1014                                 used += 20;
1015                                 break;
1016                         case OBJ_OFS_DELTA:
1017                                 buf = use_pack(p, &w_curs,
1018                                         entry->in_pack_offset + used, NULL);
1019                                 used_0 = 0;
1020                                 c = buf[used_0++];
1021                                 ofs = c & 127;
1022                                 while (c & 128) {
1023                                         ofs += 1;
1024                                         if (!ofs || MSB(ofs, 7))
1025                                                 die("delta base offset overflow in pack for %s",
1026                                                     sha1_to_hex(entry->sha1));
1027                                         c = buf[used_0++];
1028                                         ofs = (ofs << 7) + (c & 127);
1029                                 }
1030                                 if (ofs >= entry->in_pack_offset)
1031                                         die("delta base offset out of bound for %s",
1032                                             sha1_to_hex(entry->sha1));
1033                                 ofs = entry->in_pack_offset - ofs;
1034                                 base_name = find_packed_object_name(p, ofs);
1035                                 used += used_0;
1036                                 break;
1037                         default:
1038                                 base_name = NULL;
1039                         }
1040                         if (base_name)
1041                                 base_entry = locate_object_entry(base_name);
1042                 }
1043                 unuse_pack(&w_curs);
1044                 entry->in_pack_header_size = used;
1045
1046                 if (base_entry) {
1047
1048                         /* Depth value does not matter - find_deltas()
1049                          * will never consider reused delta as the
1050                          * base object to deltify other objects
1051                          * against, in order to avoid circular deltas.
1052                          */
1053
1054                         /* uncompressed size of the delta data */
1055                         entry->size = size;
1056                         entry->delta = base_entry;
1057                         entry->type = entry->in_pack_type;
1058
1059                         entry->delta_sibling = base_entry->delta_child;
1060                         base_entry->delta_child = entry;
1061
1062                         return;
1063                 }
1064                 /* Otherwise we would do the usual */
1065         }
1066
1067         entry->type = sha1_object_info(entry->sha1, &entry->size);
1068         if (entry->type < 0)
1069                 die("unable to get type of object %s",
1070                     sha1_to_hex(entry->sha1));
1071 }
1072
1073 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1074 {
1075         struct object_entry *child = me->delta_child;
1076         unsigned int m = n;
1077         while (child) {
1078                 unsigned int c = check_delta_limit(child, n + 1);
1079                 if (m < c)
1080                         m = c;
1081                 child = child->delta_sibling;
1082         }
1083         return m;
1084 }
1085
1086 static void get_object_details(void)
1087 {
1088         uint32_t i;
1089         struct object_entry *entry;
1090
1091         prepare_pack_ix();
1092         for (i = 0, entry = objects; i < nr_objects; i++, entry++)
1093                 check_object(entry);
1094
1095         if (nr_objects == nr_result) {
1096                 /*
1097                  * Depth of objects that depend on the entry -- this
1098                  * is subtracted from depth-max to break too deep
1099                  * delta chain because of delta data reusing.
1100                  * However, we loosen this restriction when we know we
1101                  * are creating a thin pack -- it will have to be
1102                  * expanded on the other end anyway, so do not
1103                  * artificially cut the delta chain and let it go as
1104                  * deep as it wants.
1105                  */
1106                 for (i = 0, entry = objects; i < nr_objects; i++, entry++)
1107                         if (!entry->delta && entry->delta_child)
1108                                 entry->delta_limit =
1109                                         check_delta_limit(entry, 1);
1110         }
1111 }
1112
1113 typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *);
1114
1115 static entry_sort_t current_sort;
1116
1117 static int sort_comparator(const void *_a, const void *_b)
1118 {
1119         struct object_entry *a = *(struct object_entry **)_a;
1120         struct object_entry *b = *(struct object_entry **)_b;
1121         return current_sort(a,b);
1122 }
1123
1124 static struct object_entry **create_sorted_list(entry_sort_t sort)
1125 {
1126         struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *));
1127         uint32_t i;
1128
1129         for (i = 0; i < nr_objects; i++)
1130                 list[i] = objects + i;
1131         current_sort = sort;
1132         qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator);
1133         return list;
1134 }
1135
1136 static int sha1_sort(const struct object_entry *a, const struct object_entry *b)
1137 {
1138         return hashcmp(a->sha1, b->sha1);
1139 }
1140
1141 static struct object_entry **create_final_object_list(void)
1142 {
1143         struct object_entry **list;
1144         uint32_t i, j;
1145
1146         for (i = nr_result = 0; i < nr_objects; i++)
1147                 if (!objects[i].preferred_base)
1148                         nr_result++;
1149         list = xmalloc(nr_result * sizeof(struct object_entry *));
1150         for (i = j = 0; i < nr_objects; i++) {
1151                 if (!objects[i].preferred_base)
1152                         list[j++] = objects + i;
1153         }
1154         current_sort = sha1_sort;
1155         qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator);
1156         return list;
1157 }
1158
1159 static int type_size_sort(const struct object_entry *a, const struct object_entry *b)
1160 {
1161         if (a->type < b->type)
1162                 return -1;
1163         if (a->type > b->type)
1164                 return 1;
1165         if (a->hash < b->hash)
1166                 return -1;
1167         if (a->hash > b->hash)
1168                 return 1;
1169         if (a->preferred_base < b->preferred_base)
1170                 return -1;
1171         if (a->preferred_base > b->preferred_base)
1172                 return 1;
1173         if (a->size < b->size)
1174                 return -1;
1175         if (a->size > b->size)
1176                 return 1;
1177         return a < b ? -1 : (a > b);
1178 }
1179
1180 struct unpacked {
1181         struct object_entry *entry;
1182         void *data;
1183         struct delta_index *index;
1184 };
1185
1186 /*
1187  * We search for deltas _backwards_ in a list sorted by type and
1188  * by size, so that we see progressively smaller and smaller files.
1189  * That's because we prefer deltas to be from the bigger file
1190  * to the smaller - deletes are potentially cheaper, but perhaps
1191  * more importantly, the bigger file is likely the more recent
1192  * one.
1193  */
1194 static int try_delta(struct unpacked *trg, struct unpacked *src,
1195                      unsigned max_depth)
1196 {
1197         struct object_entry *trg_entry = trg->entry;
1198         struct object_entry *src_entry = src->entry;
1199         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1200         enum object_type type;
1201         void *delta_buf;
1202
1203         /* Don't bother doing diffs between different types */
1204         if (trg_entry->type != src_entry->type)
1205                 return -1;
1206
1207         /* We do not compute delta to *create* objects we are not
1208          * going to pack.
1209          */
1210         if (trg_entry->preferred_base)
1211                 return -1;
1212
1213         /*
1214          * We do not bother to try a delta that we discarded
1215          * on an earlier try, but only when reusing delta data.
1216          */
1217         if (!no_reuse_delta && trg_entry->in_pack &&
1218             trg_entry->in_pack == src_entry->in_pack &&
1219             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1220             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1221                 return 0;
1222
1223         /*
1224          * If the current object is at pack edge, take the depth the
1225          * objects that depend on the current object into account --
1226          * otherwise they would become too deep.
1227          */
1228         if (trg_entry->delta_child) {
1229                 if (max_depth <= trg_entry->delta_limit)
1230                         return 0;
1231                 max_depth -= trg_entry->delta_limit;
1232         }
1233         if (src_entry->depth >= max_depth)
1234                 return 0;
1235
1236         /* Now some size filtering heuristics. */
1237         trg_size = trg_entry->size;
1238         max_size = trg_size/2 - 20;
1239         max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1240         if (max_size == 0)
1241                 return 0;
1242         if (trg_entry->delta && trg_entry->delta_size <= max_size)
1243                 max_size = trg_entry->delta_size-1;
1244         src_size = src_entry->size;
1245         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1246         if (sizediff >= max_size)
1247                 return 0;
1248
1249         /* Load data if not already done */
1250         if (!trg->data) {
1251                 trg->data = read_sha1_file(trg_entry->sha1, &type, &sz);
1252                 if (sz != trg_size)
1253                         die("object %s inconsistent object length (%lu vs %lu)",
1254                             sha1_to_hex(trg_entry->sha1), sz, trg_size);
1255         }
1256         if (!src->data) {
1257                 src->data = read_sha1_file(src_entry->sha1, &type, &sz);
1258                 if (sz != src_size)
1259                         die("object %s inconsistent object length (%lu vs %lu)",
1260                             sha1_to_hex(src_entry->sha1), sz, src_size);
1261         }
1262         if (!src->index) {
1263                 src->index = create_delta_index(src->data, src_size);
1264                 if (!src->index)
1265                         die("out of memory");
1266         }
1267
1268         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1269         if (!delta_buf)
1270                 return 0;
1271
1272         trg_entry->delta = src_entry;
1273         trg_entry->delta_size = delta_size;
1274         trg_entry->depth = src_entry->depth + 1;
1275         free(delta_buf);
1276         return 1;
1277 }
1278
1279 static void progress_interval(int signum)
1280 {
1281         progress_update = 1;
1282 }
1283
1284 static void find_deltas(struct object_entry **list, int window, int depth)
1285 {
1286         uint32_t i = nr_objects, idx = 0, processed = 0;
1287         unsigned int array_size = window * sizeof(struct unpacked);
1288         struct unpacked *array;
1289         unsigned last_percent = 999;
1290
1291         if (!nr_objects)
1292                 return;
1293         array = xmalloc(array_size);
1294         memset(array, 0, array_size);
1295         if (progress)
1296                 fprintf(stderr, "Deltifying %u objects.\n", nr_result);
1297
1298         do {
1299                 struct object_entry *entry = list[--i];
1300                 struct unpacked *n = array + idx;
1301                 int j;
1302
1303                 if (!entry->preferred_base)
1304                         processed++;
1305
1306                 if (progress) {
1307                         unsigned percent = processed * 100 / nr_result;
1308                         if (percent != last_percent || progress_update) {
1309                                 fprintf(stderr, "%4u%% (%u/%u) done\r",
1310                                         percent, processed, nr_result);
1311                                 progress_update = 0;
1312                                 last_percent = percent;
1313                         }
1314                 }
1315
1316                 if (entry->delta)
1317                         /* This happens if we decided to reuse existing
1318                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1319                          */
1320                         continue;
1321
1322                 if (entry->size < 50)
1323                         continue;
1324                 free_delta_index(n->index);
1325                 n->index = NULL;
1326                 free(n->data);
1327                 n->data = NULL;
1328                 n->entry = entry;
1329
1330                 j = window;
1331                 while (--j > 0) {
1332                         uint32_t other_idx = idx + j;
1333                         struct unpacked *m;
1334                         if (other_idx >= window)
1335                                 other_idx -= window;
1336                         m = array + other_idx;
1337                         if (!m->entry)
1338                                 break;
1339                         if (try_delta(n, m, depth) < 0)
1340                                 break;
1341                 }
1342                 /* if we made n a delta, and if n is already at max
1343                  * depth, leaving it in the window is pointless.  we
1344                  * should evict it first.
1345                  */
1346                 if (entry->delta && depth <= entry->depth)
1347                         continue;
1348
1349                 idx++;
1350                 if (idx >= window)
1351                         idx = 0;
1352         } while (i > 0);
1353
1354         if (progress)
1355                 fputc('\n', stderr);
1356
1357         for (i = 0; i < window; ++i) {
1358                 free_delta_index(array[i].index);
1359                 free(array[i].data);
1360         }
1361         free(array);
1362 }
1363
1364 static void prepare_pack(int window, int depth)
1365 {
1366         get_object_details();
1367         sorted_by_type = create_sorted_list(type_size_sort);
1368         if (window && depth)
1369                 find_deltas(sorted_by_type, window+1, depth);
1370 }
1371
1372 static int reuse_cached_pack(unsigned char *sha1)
1373 {
1374         static const char cache[] = "pack-cache/pack-%s.%s";
1375         char *cached_pack, *cached_idx;
1376         int ifd, ofd, ifd_ix = -1;
1377
1378         cached_pack = git_path(cache, sha1_to_hex(sha1), "pack");
1379         ifd = open(cached_pack, O_RDONLY);
1380         if (ifd < 0)
1381                 return 0;
1382
1383         if (!pack_to_stdout) {
1384                 cached_idx = git_path(cache, sha1_to_hex(sha1), "idx");
1385                 ifd_ix = open(cached_idx, O_RDONLY);
1386                 if (ifd_ix < 0) {
1387                         close(ifd);
1388                         return 0;
1389                 }
1390         }
1391
1392         if (progress)
1393                 fprintf(stderr, "Reusing %u objects pack %s\n", nr_objects,
1394                         sha1_to_hex(sha1));
1395
1396         if (pack_to_stdout) {
1397                 if (copy_fd(ifd, 1))
1398                         exit(1);
1399                 close(ifd);
1400         }
1401         else {
1402                 char name[PATH_MAX];
1403                 snprintf(name, sizeof(name),
1404                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack");
1405                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1406                 if (ofd < 0)
1407                         die("unable to open %s (%s)", name, strerror(errno));
1408                 if (copy_fd(ifd, ofd))
1409                         exit(1);
1410                 close(ifd);
1411
1412                 snprintf(name, sizeof(name),
1413                          "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx");
1414                 ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666);
1415                 if (ofd < 0)
1416                         die("unable to open %s (%s)", name, strerror(errno));
1417                 if (copy_fd(ifd_ix, ofd))
1418                         exit(1);
1419                 close(ifd_ix);
1420                 puts(sha1_to_hex(sha1));
1421         }
1422
1423         return 1;
1424 }
1425
1426 static void setup_progress_signal(void)
1427 {
1428         struct sigaction sa;
1429         struct itimerval v;
1430
1431         memset(&sa, 0, sizeof(sa));
1432         sa.sa_handler = progress_interval;
1433         sigemptyset(&sa.sa_mask);
1434         sa.sa_flags = SA_RESTART;
1435         sigaction(SIGALRM, &sa, NULL);
1436
1437         v.it_interval.tv_sec = 1;
1438         v.it_interval.tv_usec = 0;
1439         v.it_value = v.it_interval;
1440         setitimer(ITIMER_REAL, &v, NULL);
1441 }
1442
1443 static int git_pack_config(const char *k, const char *v)
1444 {
1445         if(!strcmp(k, "pack.window")) {
1446                 window = git_config_int(k, v);
1447                 return 0;
1448         }
1449         return git_default_config(k, v);
1450 }
1451
1452 static void read_object_list_from_stdin(void)
1453 {
1454         char line[40 + 1 + PATH_MAX + 2];
1455         unsigned char sha1[20];
1456         unsigned hash;
1457
1458         for (;;) {
1459                 if (!fgets(line, sizeof(line), stdin)) {
1460                         if (feof(stdin))
1461                                 break;
1462                         if (!ferror(stdin))
1463                                 die("fgets returned NULL, not EOF, not error!");
1464                         if (errno != EINTR)
1465                                 die("fgets: %s", strerror(errno));
1466                         clearerr(stdin);
1467                         continue;
1468                 }
1469                 if (line[0] == '-') {
1470                         if (get_sha1_hex(line+1, sha1))
1471                                 die("expected edge sha1, got garbage:\n %s",
1472                                     line);
1473                         add_preferred_base(sha1);
1474                         continue;
1475                 }
1476                 if (get_sha1_hex(line, sha1))
1477                         die("expected sha1, got garbage:\n %s", line);
1478
1479                 hash = name_hash(line+41);
1480                 add_preferred_base_object(line+41, hash);
1481                 add_object_entry(sha1, hash, 0);
1482         }
1483 }
1484
1485 static void show_commit(struct commit *commit)
1486 {
1487         unsigned hash = name_hash("");
1488         add_preferred_base_object("", hash);
1489         add_object_entry(commit->object.sha1, hash, 0);
1490 }
1491
1492 static void show_object(struct object_array_entry *p)
1493 {
1494         unsigned hash = name_hash(p->name);
1495         add_preferred_base_object(p->name, hash);
1496         add_object_entry(p->item->sha1, hash, 0);
1497 }
1498
1499 static void show_edge(struct commit *commit)
1500 {
1501         add_preferred_base(commit->object.sha1);
1502 }
1503
1504 static void get_object_list(int ac, const char **av)
1505 {
1506         struct rev_info revs;
1507         char line[1000];
1508         int flags = 0;
1509
1510         init_revisions(&revs, NULL);
1511         save_commit_buffer = 0;
1512         track_object_refs = 0;
1513         setup_revisions(ac, av, &revs, NULL);
1514
1515         while (fgets(line, sizeof(line), stdin) != NULL) {
1516                 int len = strlen(line);
1517                 if (line[len - 1] == '\n')
1518                         line[--len] = 0;
1519                 if (!len)
1520                         break;
1521                 if (*line == '-') {
1522                         if (!strcmp(line, "--not")) {
1523                                 flags ^= UNINTERESTING;
1524                                 continue;
1525                         }
1526                         die("not a rev '%s'", line);
1527                 }
1528                 if (handle_revision_arg(line, &revs, flags, 1))
1529                         die("bad revision '%s'", line);
1530         }
1531
1532         prepare_revision_walk(&revs);
1533         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1534         traverse_commit_list(&revs, show_commit, show_object);
1535 }
1536
1537 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1538 {
1539         SHA_CTX ctx;
1540         int depth = 10;
1541         struct object_entry **list;
1542         int use_internal_rev_list = 0;
1543         int thin = 0;
1544         uint32_t i;
1545         const char **rp_av;
1546         int rp_ac_alloc = 64;
1547         int rp_ac;
1548
1549         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1550
1551         rp_av[0] = "pack-objects";
1552         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1553         rp_ac = 2;
1554
1555         git_config(git_pack_config);
1556
1557         progress = isatty(2);
1558         for (i = 1; i < argc; i++) {
1559                 const char *arg = argv[i];
1560
1561                 if (*arg != '-')
1562                         break;
1563
1564                 if (!strcmp("--non-empty", arg)) {
1565                         non_empty = 1;
1566                         continue;
1567                 }
1568                 if (!strcmp("--local", arg)) {
1569                         local = 1;
1570                         continue;
1571                 }
1572                 if (!strcmp("--incremental", arg)) {
1573                         incremental = 1;
1574                         continue;
1575                 }
1576                 if (!prefixcmp(arg, "--window=")) {
1577                         char *end;
1578                         window = strtoul(arg+9, &end, 0);
1579                         if (!arg[9] || *end)
1580                                 usage(pack_usage);
1581                         continue;
1582                 }
1583                 if (!prefixcmp(arg, "--depth=")) {
1584                         char *end;
1585                         depth = strtoul(arg+8, &end, 0);
1586                         if (!arg[8] || *end)
1587                                 usage(pack_usage);
1588                         continue;
1589                 }
1590                 if (!strcmp("--progress", arg)) {
1591                         progress = 1;
1592                         continue;
1593                 }
1594                 if (!strcmp("--all-progress", arg)) {
1595                         progress = 2;
1596                         continue;
1597                 }
1598                 if (!strcmp("-q", arg)) {
1599                         progress = 0;
1600                         continue;
1601                 }
1602                 if (!strcmp("--no-reuse-delta", arg)) {
1603                         no_reuse_delta = 1;
1604                         continue;
1605                 }
1606                 if (!strcmp("--delta-base-offset", arg)) {
1607                         allow_ofs_delta = 1;
1608                         continue;
1609                 }
1610                 if (!strcmp("--stdout", arg)) {
1611                         pack_to_stdout = 1;
1612                         continue;
1613                 }
1614                 if (!strcmp("--revs", arg)) {
1615                         use_internal_rev_list = 1;
1616                         continue;
1617                 }
1618                 if (!strcmp("--unpacked", arg) ||
1619                     !prefixcmp(arg, "--unpacked=") ||
1620                     !strcmp("--reflog", arg) ||
1621                     !strcmp("--all", arg)) {
1622                         use_internal_rev_list = 1;
1623                         if (rp_ac >= rp_ac_alloc - 1) {
1624                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
1625                                 rp_av = xrealloc(rp_av,
1626                                                  rp_ac_alloc * sizeof(*rp_av));
1627                         }
1628                         rp_av[rp_ac++] = arg;
1629                         continue;
1630                 }
1631                 if (!strcmp("--thin", arg)) {
1632                         use_internal_rev_list = 1;
1633                         thin = 1;
1634                         rp_av[1] = "--objects-edge";
1635                         continue;
1636                 }
1637                 usage(pack_usage);
1638         }
1639
1640         /* Traditionally "pack-objects [options] base extra" failed;
1641          * we would however want to take refs parameter that would
1642          * have been given to upstream rev-list ourselves, which means
1643          * we somehow want to say what the base name is.  So the
1644          * syntax would be:
1645          *
1646          * pack-objects [options] base <refs...>
1647          *
1648          * in other words, we would treat the first non-option as the
1649          * base_name and send everything else to the internal revision
1650          * walker.
1651          */
1652
1653         if (!pack_to_stdout)
1654                 base_name = argv[i++];
1655
1656         if (pack_to_stdout != !base_name)
1657                 usage(pack_usage);
1658
1659         if (!pack_to_stdout && thin)
1660                 die("--thin cannot be used to build an indexable pack.");
1661
1662         prepare_packed_git();
1663
1664         if (progress) {
1665                 fprintf(stderr, "Generating pack...\n");
1666                 setup_progress_signal();
1667         }
1668
1669         if (!use_internal_rev_list)
1670                 read_object_list_from_stdin();
1671         else {
1672                 rp_av[rp_ac] = NULL;
1673                 get_object_list(rp_ac, rp_av);
1674         }
1675
1676         if (progress)
1677                 fprintf(stderr, "Done counting %u objects.\n", nr_objects);
1678         sorted_by_sha = create_final_object_list();
1679         if (non_empty && !nr_result)
1680                 return 0;
1681
1682         SHA1_Init(&ctx);
1683         list = sorted_by_sha;
1684         for (i = 0; i < nr_result; i++) {
1685                 struct object_entry *entry = *list++;
1686                 SHA1_Update(&ctx, entry->sha1, 20);
1687         }
1688         SHA1_Final(object_list_sha1, &ctx);
1689         if (progress && (nr_objects != nr_result))
1690                 fprintf(stderr, "Result has %u objects.\n", nr_result);
1691
1692         if (reuse_cached_pack(object_list_sha1))
1693                 ;
1694         else {
1695                 if (nr_result)
1696                         prepare_pack(window, depth);
1697                 if (progress == 1 && pack_to_stdout) {
1698                         /* the other end usually displays progress itself */
1699                         struct itimerval v = {{0,},};
1700                         setitimer(ITIMER_REAL, &v, NULL);
1701                         signal(SIGALRM, SIG_IGN );
1702                         progress_update = 0;
1703                 }
1704                 write_pack_file();
1705                 if (!pack_to_stdout) {
1706                         write_index_file();
1707                         puts(sha1_to_hex(object_list_sha1));
1708                 }
1709         }
1710         if (progress)
1711                 fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
1712                         written, written_delta, reused, reused_delta);
1713         return 0;
1714 }