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