builtin-pack-objects.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "attr.h"
   4 #include "object.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "delta.h"
  10 #include "pack.h"
  11 #include "csum-file.h"
  12 #include "tree-walk.h"
  13 #include "diff.h"
  14 #include "revision.h"
  15 #include "list-objects.h"
  16 #include "progress.h"
  17
  18 #ifdef THREADED_DELTA_SEARCH
  19 #include <pthread.h>
  20 #endif
  21
  22 static const char pack_usage[] = "\
  23 git-pack-objects [{ -q | --progress | --all-progress }] \n\
  24         [--max-pack-size=N] [--local] [--incremental] \n\
  25         [--window=N] [--window-memory=N] [--depth=N] \n\
  26         [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
  27         [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
  28         [--stdout | base-name] [<ref-list | <object-list]";
  29
  30 struct object_entry {
  31         struct pack_idx_entry idx;
  32         unsigned long size;     /* uncompressed size */
  33         struct packed_git *in_pack;     /* already in pack */
  34         off_t in_pack_offset;
  35         struct object_entry *delta;     /* delta base object */
  36         struct object_entry *delta_child; /* deltified objects who bases me */
  37         struct object_entry *delta_sibling; /* other deltified objects who
  38                                              * uses the same base as me
  39                                              */
  40         void *delta_data;       /* cached delta (uncompressed) */
  41         unsigned long delta_size;       /* delta data size (uncompressed) */
  42         unsigned int hash;      /* name hint hash */
  43         enum object_type type;
  44         enum object_type in_pack_type;  /* could be delta */
  45         unsigned char in_pack_header_size;
  46         unsigned char preferred_base; /* we do not pack this, but is available
  47                                        * to be used as the base object to delta
  48                                        * objects against.
  49                                        */
  50         unsigned char no_try_delta;
  51 };
  52
  53 /*
  54  * Objects we are going to pack are collected in objects array (dynamically
  55  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  56  * in the order we see -- typically rev-list --objects order that gives us
  57  * nice "minimum seek" order.
  58  */
  59 static struct object_entry *objects;
  60 static struct object_entry **written_list;
  61 static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  62
  63 static int non_empty;
  64 static int no_reuse_delta, no_reuse_object;
  65 static int local;
  66 static int incremental;
  67 static int allow_ofs_delta;
  68 static const char *pack_tmp_name, *idx_tmp_name;
  69 static char tmpname[PATH_MAX];
  70 static const char *base_name;
  71 static int progress = 1;
  72 static int window = 10;
  73 static uint32_t pack_size_limit;
  74 static int depth = 50;
  75 static int pack_to_stdout;
  76 static int num_preferred_base;
  77 static struct progress progress_state;
  78 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  79 static int pack_compression_seen;
  80
  81 static unsigned long delta_cache_size = 0;
  82 static unsigned long max_delta_cache_size = 0;
  83 static unsigned long cache_max_small_delta_size = 1000;
  84
  85 static unsigned long window_memory_limit = 0;
  86
  87 /*
  88  * The object names in objects array are hashed with this hashtable,
  89  * to help looking up the entry by object name.
  90  * This hashtable is built after all the objects are seen.
  91  */
  92 static int *object_ix;
  93 static int object_ix_hashsz;
  94
  95 /*
  96  * Pack index for existing packs give us easy access to the offsets into
  97  * corresponding pack file where each object's data starts, but the entries
  98  * do not store the size of the compressed representation (uncompressed
  99  * size is easily available by examining the pack entry header).  It is
 100  * also rather expensive to find the sha1 for an object given its offset.
 101  *
 102  * We build a hashtable of existing packs (pack_revindex), and keep reverse
 103  * index here -- pack index file is sorted by object name mapping to offset;
 104  * this pack_revindex[].revindex array is a list of offset/index_nr pairs
 105  * ordered by offset, so if you know the offset of an object, next offset
 106  * is where its packed representation ends and the index_nr can be used to
 107  * get the object sha1 from the main index.
 108  */
 109 struct revindex_entry {
 110         off_t offset;
 111         unsigned int nr;
 112 };
 113 struct pack_revindex {
 114         struct packed_git *p;
 115         struct revindex_entry *revindex;
 116 };
 117 static struct  pack_revindex *pack_revindex;
 118 static int pack_revindex_hashsz;
 119
 120 /*
 121  * stats
 122  */
 123 static uint32_t written, written_delta;
 124 static uint32_t reused, reused_delta;
 125
 126 static int pack_revindex_ix(struct packed_git *p)
 127 {
 128         unsigned long ui = (unsigned long)p;
 129         int i;
 130
 131         ui = ui ^ (ui >> 16); /* defeat structure alignment */
 132         i = (int)(ui % pack_revindex_hashsz);
 133         while (pack_revindex[i].p) {
 134                 if (pack_revindex[i].p == p)
 135                         return i;
 136                 if (++i == pack_revindex_hashsz)
 137                         i = 0;
 138         }
 139         return -1 - i;
 140 }
 141
 142 static void prepare_pack_ix(void)
 143 {
 144         int num;
 145         struct packed_git *p;
 146         for (num = 0, p = packed_git; p; p = p->next)
 147                 num++;
 148         if (!num)
 149                 return;
 150         pack_revindex_hashsz = num * 11;
 151         pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 152         for (p = packed_git; p; p = p->next) {
 153                 num = pack_revindex_ix(p);
 154                 num = - 1 - num;
 155                 pack_revindex[num].p = p;
 156         }
 157         /* revindex elements are lazily initialized */
 158 }
 159
 160 static int cmp_offset(const void *a_, const void *b_)
 161 {
 162         const struct revindex_entry *a = a_;
 163         const struct revindex_entry *b = b_;
 164         return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
 165 }
 166
 167 /*
 168  * Ordered list of offsets of objects in the pack.
 169  */
 170 static void prepare_pack_revindex(struct pack_revindex *rix)
 171 {
 172         struct packed_git *p = rix->p;
 173         int num_ent = p->num_objects;
 174         int i;
 175         const char *index = p->index_data;
 176
 177         rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
 178         index += 4 * 256;
 179
 180         if (p->index_version > 1) {
 181                 const uint32_t *off_32 =
 182                         (uint32_t *)(index + 8 + p->num_objects * (20 + 4));
 183                 const uint32_t *off_64 = off_32 + p->num_objects;
 184                 for (i = 0; i < num_ent; i++) {
 185                         uint32_t off = ntohl(*off_32++);
 186                         if (!(off & 0x80000000)) {
 187                                 rix->revindex[i].offset = off;
 188                         } else {
 189                                 rix->revindex[i].offset =
 190                                         ((uint64_t)ntohl(*off_64++)) << 32;
 191                                 rix->revindex[i].offset |=
 192                                         ntohl(*off_64++);
 193                         }
 194                         rix->revindex[i].nr = i;
 195                 }
 196         } else {
 197                 for (i = 0; i < num_ent; i++) {
 198                         uint32_t hl = *((uint32_t *)(index + 24 * i));
 199                         rix->revindex[i].offset = ntohl(hl);
 200                         rix->revindex[i].nr = i;
 201                 }
 202         }
 203
 204         /* This knows the pack format -- the 20-byte trailer
 205          * follows immediately after the last object data.
 206          */
 207         rix->revindex[num_ent].offset = p->pack_size - 20;
 208         rix->revindex[num_ent].nr = -1;
 209         qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
 210 }
 211
 212 static struct revindex_entry * find_packed_object(struct packed_git *p,
 213                                                   off_t ofs)
 214 {
 215         int num;
 216         int lo, hi;
 217         struct pack_revindex *rix;
 218         struct revindex_entry *revindex;
 219         num = pack_revindex_ix(p);
 220         if (num < 0)
 221                 die("internal error: pack revindex uninitialized");
 222         rix = &pack_revindex[num];
 223         if (!rix->revindex)
 224                 prepare_pack_revindex(rix);
 225         revindex = rix->revindex;
 226         lo = 0;
 227         hi = p->num_objects + 1;
 228         do {
 229                 int mi = (lo + hi) / 2;
 230                 if (revindex[mi].offset == ofs) {
 231                         return revindex + mi;
 232                 }
 233                 else if (ofs < revindex[mi].offset)
 234                         hi = mi;
 235                 else
 236                         lo = mi + 1;
 237         } while (lo < hi);
 238         die("internal error: pack revindex corrupt");
 239 }
 240
 241 static const unsigned char *find_packed_object_name(struct packed_git *p,
 242                                                     off_t ofs)
 243 {
 244         struct revindex_entry *entry = find_packed_object(p, ofs);
 245         return nth_packed_object_sha1(p, entry->nr);
 246 }
 247
 248 static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 249 {
 250         unsigned long othersize, delta_size;
 251         enum object_type type;
 252         void *otherbuf = read_sha1_file(entry->delta->idx.sha1, &type, &othersize);
 253         void *delta_buf;
 254
 255         if (!otherbuf)
 256                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 257         delta_buf = diff_delta(otherbuf, othersize,
 258                                buf, size, &delta_size, 0);
 259         if (!delta_buf || delta_size != entry->delta_size)
 260                 die("delta size changed");
 261         free(buf);
 262         free(otherbuf);
 263         return delta_buf;
 264 }
 265
 266 /*
 267  * The per-object header is a pretty dense thing, which is
 268  *  - first byte: low four bits are "size", then three bits of "type",
 269  *    and the high bit is "size continues".
 270  *  - each byte afterwards: low seven bits are size continuation,
 271  *    with the high bit being "size continues"
 272  */
 273 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 274 {
 275         int n = 1;
 276         unsigned char c;
 277
 278         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 279                 die("bad type %d", type);
 280
 281         c = (type << 4) | (size & 15);
 282         size >>= 4;
 283         while (size) {
 284                 *hdr++ = c | 0x80;
 285                 c = size & 0x7f;
 286                 size >>= 7;
 287                 n++;
 288         }
 289         *hdr = c;
 290         return n;
 291 }
 292
 293 /*
 294  * we are going to reuse the existing object data as is.  make
 295  * sure it is not corrupt.
 296  */
 297 static int check_pack_inflate(struct packed_git *p,
 298                 struct pack_window **w_curs,
 299                 off_t offset,
 300                 off_t len,
 301                 unsigned long expect)
 302 {
 303         z_stream stream;
 304         unsigned char fakebuf[4096], *in;
 305         int st;
 306
 307         memset(&stream, 0, sizeof(stream));
 308         inflateInit(&stream);
 309         do {
 310                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 311                 stream.next_in = in;
 312                 stream.next_out = fakebuf;
 313                 stream.avail_out = sizeof(fakebuf);
 314                 st = inflate(&stream, Z_FINISH);
 315                 offset += stream.next_in - in;
 316         } while (st == Z_OK || st == Z_BUF_ERROR);
 317         inflateEnd(&stream);
 318         return (st == Z_STREAM_END &&
 319                 stream.total_out == expect &&
 320                 stream.total_in == len) ? 0 : -1;
 321 }
 322
 323 static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
 324                           off_t offset, off_t len, unsigned int nr)
 325 {
 326         const uint32_t *index_crc;
 327         uint32_t data_crc = crc32(0, Z_NULL, 0);
 328
 329         do {
 330                 unsigned int avail;
 331                 void *data = use_pack(p, w_curs, offset, &avail);
 332                 if (avail > len)
 333                         avail = len;
 334                 data_crc = crc32(data_crc, data, avail);
 335                 offset += avail;
 336                 len -= avail;
 337         } while (len);
 338
 339         index_crc = p->index_data;
 340         index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
 341
 342         return data_crc != ntohl(*index_crc);
 343 }
 344
 345 static void copy_pack_data(struct sha1file *f,
 346                 struct packed_git *p,
 347                 struct pack_window **w_curs,
 348                 off_t offset,
 349                 off_t len)
 350 {
 351         unsigned char *in;
 352         unsigned int avail;
 353
 354         while (len) {
 355                 in = use_pack(p, w_curs, offset, &avail);
 356                 if (avail > len)
 357                         avail = (unsigned int)len;
 358                 sha1write(f, in, avail);
 359                 offset += avail;
 360                 len -= avail;
 361         }
 362 }
 363
 364 static unsigned long write_object(struct sha1file *f,
 365                                   struct object_entry *entry,
 366                                   off_t write_offset)
 367 {
 368         unsigned long size;
 369         enum object_type type;
 370         void *buf;
 371         unsigned char header[10];
 372         unsigned char dheader[10];
 373         unsigned hdrlen;
 374         off_t datalen;
 375         enum object_type obj_type;
 376         int to_reuse = 0;
 377         /* write limit if limited packsize and not first object */
 378         unsigned long limit = pack_size_limit && nr_written ?
 379                                 pack_size_limit - write_offset : 0;
 380                                 /* no if no delta */
 381         int usable_delta =      !entry->delta ? 0 :
 382                                 /* yes if unlimited packfile */
 383                                 !pack_size_limit ? 1 :
 384                                 /* no if base written to previous pack */
 385                                 entry->delta->idx.offset == (off_t)-1 ? 0 :
 386                                 /* otherwise double-check written to this
 387                                  * pack,  like we do below
 388                                  */
 389                                 entry->delta->idx.offset ? 1 : 0;
 390
 391         if (!pack_to_stdout)
 392                 crc32_begin(f);
 393
 394         obj_type = entry->type;
 395         if (no_reuse_object)
 396                 to_reuse = 0;   /* explicit */
 397         else if (!entry->in_pack)
 398                 to_reuse = 0;   /* can't reuse what we don't have */
 399         else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 400                                 /* check_object() decided it for us ... */
 401                 to_reuse = usable_delta;
 402                                 /* ... but pack split may override that */
 403         else if (obj_type != entry->in_pack_type)
 404                 to_reuse = 0;   /* pack has delta which is unusable */
 405         else if (entry->delta)
 406                 to_reuse = 0;   /* we want to pack afresh */
 407         else
 408                 to_reuse = 1;   /* we have it in-pack undeltified,
 409                                  * and we do not need to deltify it.
 410                                  */
 411
 412         if (!to_reuse) {
 413                 z_stream stream;
 414                 unsigned long maxsize;
 415                 void *out;
 416                 if (!usable_delta) {
 417                         buf = read_sha1_file(entry->idx.sha1, &obj_type, &size);
 418                         if (!buf)
 419                                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 420                 } else if (entry->delta_data) {
 421                         size = entry->delta_size;
 422                         buf = entry->delta_data;
 423                         entry->delta_data = NULL;
 424                         obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 425                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 426                 } else {
 427                         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 428                         if (!buf)
 429                                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 430                         buf = delta_against(buf, size, entry);
 431                         size = entry->delta_size;
 432                         obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 433                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 434                 }
 435                 /* compress the data to store and put compressed length in datalen */
 436                 memset(&stream, 0, sizeof(stream));
 437                 deflateInit(&stream, pack_compression_level);
 438                 maxsize = deflateBound(&stream, size);
 439                 out = xmalloc(maxsize);
 440                 /* Compress it */
 441                 stream.next_in = buf;
 442                 stream.avail_in = size;
 443                 stream.next_out = out;
 444                 stream.avail_out = maxsize;
 445                 while (deflate(&stream, Z_FINISH) == Z_OK)
 446                         /* nothing */;
 447                 deflateEnd(&stream);
 448                 datalen = stream.total_out;
 449                 deflateEnd(&stream);
 450                 /*
 451                  * The object header is a byte of 'type' followed by zero or
 452                  * more bytes of length.
 453                  */
 454                 hdrlen = encode_header(obj_type, size, header);
 455
 456                 if (obj_type == OBJ_OFS_DELTA) {
 457                         /*
 458                          * Deltas with relative base contain an additional
 459                          * encoding of the relative offset for the delta
 460                          * base from this object's position in the pack.
 461                          */
 462                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 463                         unsigned pos = sizeof(dheader) - 1;
 464                         dheader[pos] = ofs & 127;
 465                         while (ofs >>= 7)
 466                                 dheader[--pos] = 128 | (--ofs & 127);
 467                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 468                                 free(out);
 469                                 free(buf);
 470                                 return 0;
 471                         }
 472                         sha1write(f, header, hdrlen);
 473                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 474                         hdrlen += sizeof(dheader) - pos;
 475                 } else if (obj_type == OBJ_REF_DELTA) {
 476                         /*
 477                          * Deltas with a base reference contain
 478                          * an additional 20 bytes for the base sha1.
 479                          */
 480                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 481                                 free(out);
 482                                 free(buf);
 483                                 return 0;
 484                         }
 485                         sha1write(f, header, hdrlen);
 486                         sha1write(f, entry->delta->idx.sha1, 20);
 487                         hdrlen += 20;
 488                 } else {
 489                         if (limit && hdrlen + datalen + 20 >= limit) {
 490                                 free(out);
 491                                 free(buf);
 492                                 return 0;
 493                         }
 494                         sha1write(f, header, hdrlen);
 495                 }
 496                 sha1write(f, out, datalen);
 497                 free(out);
 498                 free(buf);
 499         }
 500         else {
 501                 struct packed_git *p = entry->in_pack;
 502                 struct pack_window *w_curs = NULL;
 503                 struct revindex_entry *revidx;
 504                 off_t offset;
 505
 506                 if (entry->delta) {
 507                         obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 508                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 509                         reused_delta++;
 510                 }
 511                 hdrlen = encode_header(obj_type, entry->size, header);
 512                 offset = entry->in_pack_offset;
 513                 revidx = find_packed_object(p, offset);
 514                 datalen = revidx[1].offset - offset;
 515                 if (!pack_to_stdout && p->index_version > 1 &&
 516                     check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
 517                         die("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 518                 offset += entry->in_pack_header_size;
 519                 datalen -= entry->in_pack_header_size;
 520                 if (obj_type == OBJ_OFS_DELTA) {
 521                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 522                         unsigned pos = sizeof(dheader) - 1;
 523                         dheader[pos] = ofs & 127;
 524                         while (ofs >>= 7)
 525                                 dheader[--pos] = 128 | (--ofs & 127);
 526                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit)
 527                                 return 0;
 528                         sha1write(f, header, hdrlen);
 529                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 530                         hdrlen += sizeof(dheader) - pos;
 531                 } else if (obj_type == OBJ_REF_DELTA) {
 532                         if (limit && hdrlen + 20 + datalen + 20 >= limit)
 533                                 return 0;
 534                         sha1write(f, header, hdrlen);
 535                         sha1write(f, entry->delta->idx.sha1, 20);
 536                         hdrlen += 20;
 537                 } else {
 538                         if (limit && hdrlen + datalen + 20 >= limit)
 539                                 return 0;
 540                         sha1write(f, header, hdrlen);
 541                 }
 542
 543                 if (!pack_to_stdout && p->index_version == 1 &&
 544                     check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
 545                         die("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 546                 copy_pack_data(f, p, &w_curs, offset, datalen);
 547                 unuse_pack(&w_curs);
 548                 reused++;
 549         }
 550         if (usable_delta)
 551                 written_delta++;
 552         written++;
 553         if (!pack_to_stdout)
 554                 entry->idx.crc32 = crc32_end(f);
 555         return hdrlen + datalen;
 556 }
 557
 558 static off_t write_one(struct sha1file *f,
 559                                struct object_entry *e,
 560                                off_t offset)
 561 {
 562         unsigned long size;
 563
 564         /* offset is non zero if object is written already. */
 565         if (e->idx.offset || e->preferred_base)
 566                 return offset;
 567
 568         /* if we are deltified, write out base object first. */
 569         if (e->delta) {
 570                 offset = write_one(f, e->delta, offset);
 571                 if (!offset)
 572                         return 0;
 573         }
 574
 575         e->idx.offset = offset;
 576         size = write_object(f, e, offset);
 577         if (!size) {
 578                 e->idx.offset = 0;
 579                 return 0;
 580         }
 581         written_list[nr_written++] = e;
 582
 583         /* make sure off_t is sufficiently large not to wrap */
 584         if (offset > offset + size)
 585                 die("pack too large for current definition of off_t");
 586         return offset + size;
 587 }
 588
 589 static int open_object_dir_tmp(const char *path)
 590 {
 591     snprintf(tmpname, sizeof(tmpname), "%s/%s", get_object_directory(), path);
 592     return xmkstemp(tmpname);
 593 }
 594
 595 /* forward declaration for write_pack_file */
 596 static int adjust_perm(const char *path, mode_t mode);
 597
 598 static void write_pack_file(void)
 599 {
 600         uint32_t i = 0, j;
 601         struct sha1file *f;
 602         off_t offset, offset_one, last_obj_offset = 0;
 603         struct pack_header hdr;
 604         int do_progress = progress >> pack_to_stdout;
 605         uint32_t nr_remaining = nr_result;
 606
 607         if (do_progress)
 608                 start_progress(&progress_state, "Writing %u objects...", "", nr_result);
 609         written_list = xmalloc(nr_objects * sizeof(struct object_entry *));
 610
 611         do {
 612                 unsigned char sha1[20];
 613
 614                 if (pack_to_stdout) {
 615                         f = sha1fd(1, "<stdout>");
 616                 } else {
 617                         int fd = open_object_dir_tmp("tmp_pack_XXXXXX");
 618                         pack_tmp_name = xstrdup(tmpname);
 619                         f = sha1fd(fd, pack_tmp_name);
 620                 }
 621
 622                 hdr.hdr_signature = htonl(PACK_SIGNATURE);
 623                 hdr.hdr_version = htonl(PACK_VERSION);
 624                 hdr.hdr_entries = htonl(nr_remaining);
 625                 sha1write(f, &hdr, sizeof(hdr));
 626                 offset = sizeof(hdr);
 627                 nr_written = 0;
 628                 for (; i < nr_objects; i++) {
 629                         last_obj_offset = offset;
 630                         offset_one = write_one(f, objects + i, offset);
 631                         if (!offset_one)
 632                                 break;
 633                         offset = offset_one;
 634                         if (do_progress)
 635                                 display_progress(&progress_state, written);
 636                 }
 637
 638                 /*
 639                  * Did we write the wrong # entries in the header?
 640                  * If so, rewrite it like in fast-import
 641                  */
 642                 if (pack_to_stdout || nr_written == nr_remaining) {
 643                         sha1close(f, sha1, 1);
 644                 } else {
 645                         sha1close(f, sha1, 0);
 646                         fixup_pack_header_footer(f->fd, sha1, pack_tmp_name, nr_written);
 647                         close(f->fd);
 648                 }
 649
 650                 if (!pack_to_stdout) {
 651                         mode_t mode = umask(0);
 652
 653                         umask(mode);
 654                         mode = 0444 & ~mode;
 655
 656                         idx_tmp_name = write_idx_file(NULL,
 657                                 (struct pack_idx_entry **) written_list, nr_written, sha1);
 658                         snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
 659                                  base_name, sha1_to_hex(sha1));
 660                         if (adjust_perm(pack_tmp_name, mode))
 661                                 die("unable to make temporary pack file readable: %s",
 662                                     strerror(errno));
 663                         if (rename(pack_tmp_name, tmpname))
 664                                 die("unable to rename temporary pack file: %s",
 665                                     strerror(errno));
 666                         snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
 667                                  base_name, sha1_to_hex(sha1));
 668                         if (adjust_perm(idx_tmp_name, mode))
 669                                 die("unable to make temporary index file readable: %s",
 670                                     strerror(errno));
 671                         if (rename(idx_tmp_name, tmpname))
 672                                 die("unable to rename temporary index file: %s",
 673                                     strerror(errno));
 674                         puts(sha1_to_hex(sha1));
 675                 }
 676
 677                 /* mark written objects as written to previous pack */
 678                 for (j = 0; j < nr_written; j++) {
 679                         written_list[j]->idx.offset = (off_t)-1;
 680                 }
 681                 nr_remaining -= nr_written;
 682         } while (nr_remaining && i < nr_objects);
 683
 684         free(written_list);
 685         if (do_progress)
 686                 stop_progress(&progress_state);
 687         if (written != nr_result)
 688                 die("wrote %u objects while expecting %u", written, nr_result);
 689         /*
 690          * We have scanned through [0 ... i).  Since we have written
 691          * the correct number of objects,  the remaining [i ... nr_objects)
 692          * items must be either already written (due to out-of-order delta base)
 693          * or a preferred base.  Count those which are neither and complain if any.
 694          */
 695         for (j = 0; i < nr_objects; i++) {
 696                 struct object_entry *e = objects + i;
 697                 j += !e->idx.offset && !e->preferred_base;
 698         }
 699         if (j)
 700                 die("wrote %u objects as expected but %u unwritten", written, j);
 701 }
 702
 703 static int locate_object_entry_hash(const unsigned char *sha1)
 704 {
 705         int i;
 706         unsigned int ui;
 707         memcpy(&ui, sha1, sizeof(unsigned int));
 708         i = ui % object_ix_hashsz;
 709         while (0 < object_ix[i]) {
 710                 if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 711                         return i;
 712                 if (++i == object_ix_hashsz)
 713                         i = 0;
 714         }
 715         return -1 - i;
 716 }
 717
 718 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 719 {
 720         int i;
 721
 722         if (!object_ix_hashsz)
 723                 return NULL;
 724
 725         i = locate_object_entry_hash(sha1);
 726         if (0 <= i)
 727                 return &objects[object_ix[i]-1];
 728         return NULL;
 729 }
 730
 731 static void rehash_objects(void)
 732 {
 733         uint32_t i;
 734         struct object_entry *oe;
 735
 736         object_ix_hashsz = nr_objects * 3;
 737         if (object_ix_hashsz < 1024)
 738                 object_ix_hashsz = 1024;
 739         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 740         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 741         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 742                 int ix = locate_object_entry_hash(oe->idx.sha1);
 743                 if (0 <= ix)
 744                         continue;
 745                 ix = -1 - ix;
 746                 object_ix[ix] = i + 1;
 747         }
 748 }
 749
 750 static unsigned name_hash(const char *name)
 751 {
 752         unsigned char c;
 753         unsigned hash = 0;
 754
 755         if (!name)
 756                 return 0;
 757
 758         /*
 759          * This effectively just creates a sortable number from the
 760          * last sixteen non-whitespace characters. Last characters
 761          * count "most", so things that end in ".c" sort together.
 762          */
 763         while ((c = *name++) != 0) {
 764                 if (isspace(c))
 765                         continue;
 766                 hash = (hash >> 2) + (c << 24);
 767         }
 768         return hash;
 769 }
 770
 771 static void setup_delta_attr_check(struct git_attr_check *check)
 772 {
 773         static struct git_attr *attr_delta;
 774
 775         if (!attr_delta)
 776                 attr_delta = git_attr("delta", 5);
 777
 778         check[0].attr = attr_delta;
 779 }
 780
 781 static int no_try_delta(const char *path)
 782 {
 783         struct git_attr_check check[1];
 784
 785         setup_delta_attr_check(check);
 786         if (git_checkattr(path, ARRAY_SIZE(check), check))
 787                 return 0;
 788         if (ATTR_FALSE(check->value))
 789                 return 1;
 790         return 0;
 791 }
 792
 793 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 794                             const char *name, int exclude)
 795 {
 796         struct object_entry *entry;
 797         struct packed_git *p, *found_pack = NULL;
 798         off_t found_offset = 0;
 799         int ix;
 800         unsigned hash = name_hash(name);
 801
 802         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 803         if (ix >= 0) {
 804                 if (exclude) {
 805                         entry = objects + object_ix[ix] - 1;
 806                         if (!entry->preferred_base)
 807                                 nr_result--;
 808                         entry->preferred_base = 1;
 809                 }
 810                 return 0;
 811         }
 812
 813         for (p = packed_git; p; p = p->next) {
 814                 off_t offset = find_pack_entry_one(sha1, p);
 815                 if (offset) {
 816                         if (!found_pack) {
 817                                 found_offset = offset;
 818                                 found_pack = p;
 819                         }
 820                         if (exclude)
 821                                 break;
 822                         if (incremental)
 823                                 return 0;
 824                         if (local && !p->pack_local)
 825                                 return 0;
 826                 }
 827         }
 828
 829         if (nr_objects >= nr_alloc) {
 830                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 831                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 832         }
 833
 834         entry = objects + nr_objects++;
 835         memset(entry, 0, sizeof(*entry));
 836         hashcpy(entry->idx.sha1, sha1);
 837         entry->hash = hash;
 838         if (type)
 839                 entry->type = type;
 840         if (exclude)
 841                 entry->preferred_base = 1;
 842         else
 843                 nr_result++;
 844         if (found_pack) {
 845                 entry->in_pack = found_pack;
 846                 entry->in_pack_offset = found_offset;
 847         }
 848
 849         if (object_ix_hashsz * 3 <= nr_objects * 4)
 850                 rehash_objects();
 851         else
 852                 object_ix[-1 - ix] = nr_objects;
 853
 854         if (progress)
 855                 display_progress(&progress_state, nr_objects);
 856
 857         if (name && no_try_delta(name))
 858                 entry->no_try_delta = 1;
 859
 860         return 1;
 861 }
 862
 863 struct pbase_tree_cache {
 864         unsigned char sha1[20];
 865         int ref;
 866         int temporary;
 867         void *tree_data;
 868         unsigned long tree_size;
 869 };
 870
 871 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 872 static int pbase_tree_cache_ix(const unsigned char *sha1)
 873 {
 874         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 875 }
 876 static int pbase_tree_cache_ix_incr(int ix)
 877 {
 878         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 879 }
 880
 881 static struct pbase_tree {
 882         struct pbase_tree *next;
 883         /* This is a phony "cache" entry; we are not
 884          * going to evict it nor find it through _get()
 885          * mechanism -- this is for the toplevel node that
 886          * would almost always change with any commit.
 887          */
 888         struct pbase_tree_cache pcache;
 889 } *pbase_tree;
 890
 891 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 892 {
 893         struct pbase_tree_cache *ent, *nent;
 894         void *data;
 895         unsigned long size;
 896         enum object_type type;
 897         int neigh;
 898         int my_ix = pbase_tree_cache_ix(sha1);
 899         int available_ix = -1;
 900
 901         /* pbase-tree-cache acts as a limited hashtable.
 902          * your object will be found at your index or within a few
 903          * slots after that slot if it is cached.
 904          */
 905         for (neigh = 0; neigh < 8; neigh++) {
 906                 ent = pbase_tree_cache[my_ix];
 907                 if (ent && !hashcmp(ent->sha1, sha1)) {
 908                         ent->ref++;
 909                         return ent;
 910                 }
 911                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 912                          ((0 <= available_ix) &&
 913                           (!ent && pbase_tree_cache[available_ix])))
 914                         available_ix = my_ix;
 915                 if (!ent)
 916                         break;
 917                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 918         }
 919
 920         /* Did not find one.  Either we got a bogus request or
 921          * we need to read and perhaps cache.
 922          */
 923         data = read_sha1_file(sha1, &type, &size);
 924         if (!data)
 925                 return NULL;
 926         if (type != OBJ_TREE) {
 927                 free(data);
 928                 return NULL;
 929         }
 930
 931         /* We need to either cache or return a throwaway copy */
 932
 933         if (available_ix < 0)
 934                 ent = NULL;
 935         else {
 936                 ent = pbase_tree_cache[available_ix];
 937                 my_ix = available_ix;
 938         }
 939
 940         if (!ent) {
 941                 nent = xmalloc(sizeof(*nent));
 942                 nent->temporary = (available_ix < 0);
 943         }
 944         else {
 945                 /* evict and reuse */
 946                 free(ent->tree_data);
 947                 nent = ent;
 948         }
 949         hashcpy(nent->sha1, sha1);
 950         nent->tree_data = data;
 951         nent->tree_size = size;
 952         nent->ref = 1;
 953         if (!nent->temporary)
 954                 pbase_tree_cache[my_ix] = nent;
 955         return nent;
 956 }
 957
 958 static void pbase_tree_put(struct pbase_tree_cache *cache)
 959 {
 960         if (!cache->temporary) {
 961                 cache->ref--;
 962                 return;
 963         }
 964         free(cache->tree_data);
 965         free(cache);
 966 }
 967
 968 static int name_cmp_len(const char *name)
 969 {
 970         int i;
 971         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 972                 ;
 973         return i;
 974 }
 975
 976 static void add_pbase_object(struct tree_desc *tree,
 977                              const char *name,
 978                              int cmplen,
 979                              const char *fullname)
 980 {
 981         struct name_entry entry;
 982         int cmp;
 983
 984         while (tree_entry(tree,&entry)) {
 985                 if (S_ISGITLINK(entry.mode))
 986                         continue;
 987                 cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
 988                       memcmp(name, entry.path, cmplen);
 989                 if (cmp > 0)
 990                         continue;
 991                 if (cmp < 0)
 992                         return;
 993                 if (name[cmplen] != '/') {
 994                         add_object_entry(entry.sha1,
 995                                          S_ISDIR(entry.mode) ? OBJ_TREE : OBJ_BLOB,
 996                                          fullname, 1);
 997                         return;
 998                 }
 999                 if (S_ISDIR(entry.mode)) {
1000                         struct tree_desc sub;
1001                         struct pbase_tree_cache *tree;
1002                         const char *down = name+cmplen+1;
1003                         int downlen = name_cmp_len(down);
1004
1005                         tree = pbase_tree_get(entry.sha1);
1006                         if (!tree)
1007                                 return;
1008                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1009
1010                         add_pbase_object(&sub, down, downlen, fullname);
1011                         pbase_tree_put(tree);
1012                 }
1013         }
1014 }
1015
1016 static unsigned *done_pbase_paths;
1017 static int done_pbase_paths_num;
1018 static int done_pbase_paths_alloc;
1019 static int done_pbase_path_pos(unsigned hash)
1020 {
1021         int lo = 0;
1022         int hi = done_pbase_paths_num;
1023         while (lo < hi) {
1024                 int mi = (hi + lo) / 2;
1025                 if (done_pbase_paths[mi] == hash)
1026                         return mi;
1027                 if (done_pbase_paths[mi] < hash)
1028                         hi = mi;
1029                 else
1030                         lo = mi + 1;
1031         }
1032         return -lo-1;
1033 }
1034
1035 static int check_pbase_path(unsigned hash)
1036 {
1037         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1038         if (0 <= pos)
1039                 return 1;
1040         pos = -pos - 1;
1041         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1042                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1043                 done_pbase_paths = xrealloc(done_pbase_paths,
1044                                             done_pbase_paths_alloc *
1045                                             sizeof(unsigned));
1046         }
1047         done_pbase_paths_num++;
1048         if (pos < done_pbase_paths_num)
1049                 memmove(done_pbase_paths + pos + 1,
1050                         done_pbase_paths + pos,
1051                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1052         done_pbase_paths[pos] = hash;
1053         return 0;
1054 }
1055
1056 static void add_preferred_base_object(const char *name)
1057 {
1058         struct pbase_tree *it;
1059         int cmplen;
1060         unsigned hash = name_hash(name);
1061
1062         if (!num_preferred_base || check_pbase_path(hash))
1063                 return;
1064
1065         cmplen = name_cmp_len(name);
1066         for (it = pbase_tree; it; it = it->next) {
1067                 if (cmplen == 0) {
1068                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1069                 }
1070                 else {
1071                         struct tree_desc tree;
1072                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1073                         add_pbase_object(&tree, name, cmplen, name);
1074                 }
1075         }
1076 }
1077
1078 static void add_preferred_base(unsigned char *sha1)
1079 {
1080         struct pbase_tree *it;
1081         void *data;
1082         unsigned long size;
1083         unsigned char tree_sha1[20];
1084
1085         if (window <= num_preferred_base++)
1086                 return;
1087
1088         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1089         if (!data)
1090                 return;
1091
1092         for (it = pbase_tree; it; it = it->next) {
1093                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1094                         free(data);
1095                         return;
1096                 }
1097         }
1098
1099         it = xcalloc(1, sizeof(*it));
1100         it->next = pbase_tree;
1101         pbase_tree = it;
1102
1103         hashcpy(it->pcache.sha1, tree_sha1);
1104         it->pcache.tree_data = data;
1105         it->pcache.tree_size = size;
1106 }
1107
1108 static void check_object(struct object_entry *entry)
1109 {
1110         if (entry->in_pack) {
1111                 struct packed_git *p = entry->in_pack;
1112                 struct pack_window *w_curs = NULL;
1113                 const unsigned char *base_ref = NULL;
1114                 struct object_entry *base_entry;
1115                 unsigned long used, used_0;
1116                 unsigned int avail;
1117                 off_t ofs;
1118                 unsigned char *buf, c;
1119
1120                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1121
1122                 /*
1123                  * We want in_pack_type even if we do not reuse delta
1124                  * since non-delta representations could still be reused.
1125                  */
1126                 used = unpack_object_header_gently(buf, avail,
1127                                                    &entry->in_pack_type,
1128                                                    &entry->size);
1129
1130                 /*
1131                  * Determine if this is a delta and if so whether we can
1132                  * reuse it or not.  Otherwise let's find out as cheaply as
1133                  * possible what the actual type and size for this object is.
1134                  */
1135                 switch (entry->in_pack_type) {
1136                 default:
1137                         /* Not a delta hence we've already got all we need. */
1138                         entry->type = entry->in_pack_type;
1139                         entry->in_pack_header_size = used;
1140                         unuse_pack(&w_curs);
1141                         return;
1142                 case OBJ_REF_DELTA:
1143                         if (!no_reuse_delta && !entry->preferred_base)
1144                                 base_ref = use_pack(p, &w_curs,
1145                                                 entry->in_pack_offset + used, NULL);
1146                         entry->in_pack_header_size = used + 20;
1147                         break;
1148                 case OBJ_OFS_DELTA:
1149                         buf = use_pack(p, &w_curs,
1150                                        entry->in_pack_offset + used, NULL);
1151                         used_0 = 0;
1152                         c = buf[used_0++];
1153                         ofs = c & 127;
1154                         while (c & 128) {
1155                                 ofs += 1;
1156                                 if (!ofs || MSB(ofs, 7))
1157                                         die("delta base offset overflow in pack for %s",
1158                                             sha1_to_hex(entry->idx.sha1));
1159                                 c = buf[used_0++];
1160                                 ofs = (ofs << 7) + (c & 127);
1161                         }
1162                         if (ofs >= entry->in_pack_offset)
1163                                 die("delta base offset out of bound for %s",
1164                                     sha1_to_hex(entry->idx.sha1));
1165                         ofs = entry->in_pack_offset - ofs;
1166                         if (!no_reuse_delta && !entry->preferred_base)
1167                                 base_ref = find_packed_object_name(p, ofs);
1168                         entry->in_pack_header_size = used + used_0;
1169                         break;
1170                 }
1171
1172                 if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1173                         /*
1174                          * If base_ref was set above that means we wish to
1175                          * reuse delta data, and we even found that base
1176                          * in the list of objects we want to pack. Goodie!
1177                          *
1178                          * Depth value does not matter - find_deltas() will
1179                          * never consider reused delta as the base object to
1180                          * deltify other objects against, in order to avoid
1181                          * circular deltas.
1182                          */
1183                         entry->type = entry->in_pack_type;
1184                         entry->delta = base_entry;
1185                         entry->delta_sibling = base_entry->delta_child;
1186                         base_entry->delta_child = entry;
1187                         unuse_pack(&w_curs);
1188                         return;
1189                 }
1190
1191                 if (entry->type) {
1192                         /*
1193                          * This must be a delta and we already know what the
1194                          * final object type is.  Let's extract the actual
1195                          * object size from the delta header.
1196                          */
1197                         entry->size = get_size_from_delta(p, &w_curs,
1198                                         entry->in_pack_offset + entry->in_pack_header_size);
1199                         unuse_pack(&w_curs);
1200                         return;
1201                 }
1202
1203                 /*
1204                  * No choice but to fall back to the recursive delta walk
1205                  * with sha1_object_info() to find about the object type
1206                  * at this point...
1207                  */
1208                 unuse_pack(&w_curs);
1209         }
1210
1211         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1212         if (entry->type < 0)
1213                 die("unable to get type of object %s",
1214                     sha1_to_hex(entry->idx.sha1));
1215 }
1216
1217 static int pack_offset_sort(const void *_a, const void *_b)
1218 {
1219         const struct object_entry *a = *(struct object_entry **)_a;
1220         const struct object_entry *b = *(struct object_entry **)_b;
1221
1222         /* avoid filesystem trashing with loose objects */
1223         if (!a->in_pack && !b->in_pack)
1224                 return hashcmp(a->idx.sha1, b->idx.sha1);
1225
1226         if (a->in_pack < b->in_pack)
1227                 return -1;
1228         if (a->in_pack > b->in_pack)
1229                 return 1;
1230         return a->in_pack_offset < b->in_pack_offset ? -1 :
1231                         (a->in_pack_offset > b->in_pack_offset);
1232 }
1233
1234 static void get_object_details(void)
1235 {
1236         uint32_t i;
1237         struct object_entry **sorted_by_offset;
1238
1239         sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1240         for (i = 0; i < nr_objects; i++)
1241                 sorted_by_offset[i] = objects + i;
1242         qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1243
1244         prepare_pack_ix();
1245         for (i = 0; i < nr_objects; i++)
1246                 check_object(sorted_by_offset[i]);
1247         free(sorted_by_offset);
1248 }
1249
1250 static int type_size_sort(const void *_a, const void *_b)
1251 {
1252         const struct object_entry *a = *(struct object_entry **)_a;
1253         const struct object_entry *b = *(struct object_entry **)_b;
1254
1255         if (a->type < b->type)
1256                 return -1;
1257         if (a->type > b->type)
1258                 return 1;
1259         if (a->hash < b->hash)
1260                 return -1;
1261         if (a->hash > b->hash)
1262                 return 1;
1263         if (a->preferred_base < b->preferred_base)
1264                 return -1;
1265         if (a->preferred_base > b->preferred_base)
1266                 return 1;
1267         if (a->size < b->size)
1268                 return -1;
1269         if (a->size > b->size)
1270                 return 1;
1271         return a > b ? -1 : (a < b);  /* newest last */
1272 }
1273
1274 struct unpacked {
1275         struct object_entry *entry;
1276         void *data;
1277         struct delta_index *index;
1278         unsigned depth;
1279 };
1280
1281 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1282                            unsigned long delta_size)
1283 {
1284         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1285                 return 0;
1286
1287         if (delta_size < cache_max_small_delta_size)
1288                 return 1;
1289
1290         /* cache delta, if objects are large enough compared to delta size */
1291         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1292                 return 1;
1293
1294         return 0;
1295 }
1296
1297 #ifdef THREADED_DELTA_SEARCH
1298
1299 static pthread_mutex_t read_mutex = PTHREAD_MUTEX_INITIALIZER;
1300 #define read_lock()             pthread_mutex_lock(&read_mutex)
1301 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1302
1303 static pthread_mutex_t progress_mutex = PTHREAD_MUTEX_INITIALIZER;
1304 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1305 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1306
1307 #else
1308
1309 #define read_lock()             0
1310 #define read_unlock()           0
1311 #define progress_lock()         0
1312 #define progress_unlock()       0
1313
1314 #endif
1315
1316 /*
1317  * We search for deltas _backwards_ in a list sorted by type and
1318  * by size, so that we see progressively smaller and smaller files.
1319  * That's because we prefer deltas to be from the bigger file
1320  * to the smaller - deletes are potentially cheaper, but perhaps
1321  * more importantly, the bigger file is likely the more recent
1322  * one.
1323  */
1324 static int try_delta(struct unpacked *trg, struct unpacked *src,
1325                      unsigned max_depth, unsigned long *mem_usage)
1326 {
1327         struct object_entry *trg_entry = trg->entry;
1328         struct object_entry *src_entry = src->entry;
1329         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1330         unsigned ref_depth;
1331         enum object_type type;
1332         void *delta_buf;
1333
1334         /* Don't bother doing diffs between different types */
1335         if (trg_entry->type != src_entry->type)
1336                 return -1;
1337
1338         /*
1339          * We do not bother to try a delta that we discarded
1340          * on an earlier try, but only when reusing delta data.
1341          */
1342         if (!no_reuse_delta && trg_entry->in_pack &&
1343             trg_entry->in_pack == src_entry->in_pack &&
1344             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1345             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1346                 return 0;
1347
1348         /* Let's not bust the allowed depth. */
1349         if (src->depth >= max_depth)
1350                 return 0;
1351
1352         /* Now some size filtering heuristics. */
1353         trg_size = trg_entry->size;
1354         if (!trg_entry->delta) {
1355                 max_size = trg_size/2 - 20;
1356                 ref_depth = 1;
1357         } else {
1358                 max_size = trg_entry->delta_size;
1359                 ref_depth = trg->depth;
1360         }
1361         max_size = max_size * (max_depth - src->depth) /
1362                                                 (max_depth - ref_depth + 1);
1363         if (max_size == 0)
1364                 return 0;
1365         src_size = src_entry->size;
1366         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1367         if (sizediff >= max_size)
1368                 return 0;
1369         if (trg_size < src_size / 32)
1370                 return 0;
1371
1372         /* Load data if not already done */
1373         if (!trg->data) {
1374                 read_lock();
1375                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1376                 read_unlock();
1377                 if (!trg->data)
1378                         die("object %s cannot be read",
1379                             sha1_to_hex(trg_entry->idx.sha1));
1380                 if (sz != trg_size)
1381                         die("object %s inconsistent object length (%lu vs %lu)",
1382                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1383                 *mem_usage += sz;
1384         }
1385         if (!src->data) {
1386                 read_lock();
1387                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1388                 read_unlock();
1389                 if (!src->data)
1390                         die("object %s cannot be read",
1391                             sha1_to_hex(src_entry->idx.sha1));
1392                 if (sz != src_size)
1393                         die("object %s inconsistent object length (%lu vs %lu)",
1394                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1395                 *mem_usage += sz;
1396         }
1397         if (!src->index) {
1398                 src->index = create_delta_index(src->data, src_size);
1399                 if (!src->index) {
1400                         static int warned = 0;
1401                         if (!warned++)
1402                                 warning("suboptimal pack - out of memory");
1403                         return 0;
1404                 }
1405                 *mem_usage += sizeof_delta_index(src->index);
1406         }
1407
1408         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1409         if (!delta_buf)
1410                 return 0;
1411
1412         if (trg_entry->delta) {
1413                 /* Prefer only shallower same-sized deltas. */
1414                 if (delta_size == trg_entry->delta_size &&
1415                     src->depth + 1 >= trg->depth) {
1416                         free(delta_buf);
1417                         return 0;
1418                 }
1419         }
1420
1421         trg_entry->delta = src_entry;
1422         trg_entry->delta_size = delta_size;
1423         trg->depth = src->depth + 1;
1424
1425         if (trg_entry->delta_data) {
1426                 delta_cache_size -= trg_entry->delta_size;
1427                 free(trg_entry->delta_data);
1428                 trg_entry->delta_data = NULL;
1429         }
1430
1431         if (delta_cacheable(src_size, trg_size, delta_size)) {
1432                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1433                 delta_cache_size += trg_entry->delta_size;
1434         } else
1435                 free(delta_buf);
1436         return 1;
1437 }
1438
1439 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1440 {
1441         struct object_entry *child = me->delta_child;
1442         unsigned int m = n;
1443         while (child) {
1444                 unsigned int c = check_delta_limit(child, n + 1);
1445                 if (m < c)
1446                         m = c;
1447                 child = child->delta_sibling;
1448         }
1449         return m;
1450 }
1451
1452 static unsigned long free_unpacked(struct unpacked *n)
1453 {
1454         unsigned long freed_mem = sizeof_delta_index(n->index);
1455         free_delta_index(n->index);
1456         n->index = NULL;
1457         if (n->data) {
1458                 freed_mem += n->entry->size;
1459                 free(n->data);
1460                 n->data = NULL;
1461         }
1462         n->entry = NULL;
1463         n->depth = 0;
1464         return freed_mem;
1465 }
1466
1467 static void find_deltas(struct object_entry **list, unsigned list_size,
1468                         int window, int depth, unsigned *processed)
1469 {
1470         uint32_t i = list_size, idx = 0, count = 0;
1471         unsigned int array_size = window * sizeof(struct unpacked);
1472         struct unpacked *array;
1473         unsigned long mem_usage = 0;
1474
1475         array = xmalloc(array_size);
1476         memset(array, 0, array_size);
1477
1478         do {
1479                 struct object_entry *entry = list[--i];
1480                 struct unpacked *n = array + idx;
1481                 int j, max_depth, best_base = -1;
1482
1483                 mem_usage -= free_unpacked(n);
1484                 n->entry = entry;
1485
1486                 while (window_memory_limit &&
1487                        mem_usage > window_memory_limit &&
1488                        count > 1) {
1489                         uint32_t tail = (idx + window - count) % window;
1490                         mem_usage -= free_unpacked(array + tail);
1491                         count--;
1492                 }
1493
1494                 /* We do not compute delta to *create* objects we are not
1495                  * going to pack.
1496                  */
1497                 if (entry->preferred_base)
1498                         goto next;
1499
1500                 progress_lock();
1501                 (*processed)++;
1502                 if (progress)
1503                         display_progress(&progress_state, *processed);
1504                 progress_unlock();
1505
1506                 /*
1507                  * If the current object is at pack edge, take the depth the
1508                  * objects that depend on the current object into account
1509                  * otherwise they would become too deep.
1510                  */
1511                 max_depth = depth;
1512                 if (entry->delta_child) {
1513                         max_depth -= check_delta_limit(entry, 0);
1514                         if (max_depth <= 0)
1515                                 goto next;
1516                 }
1517
1518                 j = window;
1519                 while (--j > 0) {
1520                         int ret;
1521                         uint32_t other_idx = idx + j;
1522                         struct unpacked *m;
1523                         if (other_idx >= window)
1524                                 other_idx -= window;
1525                         m = array + other_idx;
1526                         if (!m->entry)
1527                                 break;
1528                         ret = try_delta(n, m, max_depth, &mem_usage);
1529                         if (ret < 0)
1530                                 break;
1531                         else if (ret > 0)
1532                                 best_base = other_idx;
1533                 }
1534
1535                 /* if we made n a delta, and if n is already at max
1536                  * depth, leaving it in the window is pointless.  we
1537                  * should evict it first.
1538                  */
1539                 if (entry->delta && depth <= n->depth)
1540                         continue;
1541
1542                 /*
1543                  * Move the best delta base up in the window, after the
1544                  * currently deltified object, to keep it longer.  It will
1545                  * be the first base object to be attempted next.
1546                  */
1547                 if (entry->delta) {
1548                         struct unpacked swap = array[best_base];
1549                         int dist = (window + idx - best_base) % window;
1550                         int dst = best_base;
1551                         while (dist--) {
1552                                 int src = (dst + 1) % window;
1553                                 array[dst] = array[src];
1554                                 dst = src;
1555                         }
1556                         array[dst] = swap;
1557                 }
1558
1559                 next:
1560                 idx++;
1561                 if (count + 1 < window)
1562                         count++;
1563                 if (idx >= window)
1564                         idx = 0;
1565         } while (i > 0);
1566
1567         for (i = 0; i < window; ++i) {
1568                 free_delta_index(array[i].index);
1569                 free(array[i].data);
1570         }
1571         free(array);
1572 }
1573
1574 #ifdef THREADED_DELTA_SEARCH
1575
1576 struct thread_params {
1577         pthread_t thread;
1578         struct object_entry **list;
1579         unsigned list_size;
1580         int window;
1581         int depth;
1582         unsigned *processed;
1583 };
1584
1585 static void *threaded_find_deltas(void *arg)
1586 {
1587         struct thread_params *p = arg;
1588         if (p->list_size)
1589                 find_deltas(p->list, p->list_size,
1590                             p->window, p->depth, p->processed);
1591         return NULL;
1592 }
1593
1594 #define NR_THREADS      8
1595
1596 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1597                            int window, int depth, unsigned *processed)
1598 {
1599         struct thread_params p[NR_THREADS];
1600         int i, ret;
1601
1602         for (i = 0; i < NR_THREADS; i++) {
1603                 unsigned sublist_size = list_size / (NR_THREADS - i);
1604                 p[i].list = list;
1605                 p[i].list_size = sublist_size;
1606                 p[i].window = window;
1607                 p[i].depth = depth;
1608                 p[i].processed = processed;
1609                 ret = pthread_create(&p[i].thread, NULL,
1610                                      threaded_find_deltas, &p[i]);
1611                 if (ret)
1612                         die("unable to create thread: %s", strerror(ret));
1613                 list += sublist_size;
1614                 list_size -= sublist_size;
1615         }
1616
1617         for (i = 0; i < NR_THREADS; i++) {
1618                 pthread_join(p[i].thread, NULL);
1619         }
1620 }
1621
1622 #else
1623 #define ll_find_deltas find_deltas
1624 #endif
1625
1626 static void prepare_pack(int window, int depth)
1627 {
1628         struct object_entry **delta_list;
1629         uint32_t i, n, nr_deltas;
1630
1631         get_object_details();
1632
1633         if (!nr_objects || !window || !depth)
1634                 return;
1635
1636         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1637         nr_deltas = n = 0;
1638
1639         for (i = 0; i < nr_objects; i++) {
1640                 struct object_entry *entry = objects + i;
1641
1642                 if (entry->delta)
1643                         /* This happens if we decided to reuse existing
1644                          * delta from a pack.  "!no_reuse_delta &&" is implied.
1645                          */
1646                         continue;
1647
1648                 if (entry->size < 50)
1649                         continue;
1650
1651                 if (entry->no_try_delta)
1652                         continue;
1653
1654                 if (!entry->preferred_base)
1655                         nr_deltas++;
1656
1657                 delta_list[n++] = entry;
1658         }
1659
1660         if (nr_deltas) {
1661                 unsigned nr_done = 0;
1662                 if (progress)
1663                         start_progress(&progress_state,
1664                                        "Deltifying %u objects...", "",
1665                                        nr_deltas);
1666                 qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
1667                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
1668                 if (progress)
1669                         stop_progress(&progress_state);
1670                 if (nr_done != nr_deltas)
1671                         die("inconsistency with delta count");
1672         }
1673         free(delta_list);
1674 }
1675
1676 static int git_pack_config(const char *k, const char *v)
1677 {
1678         if(!strcmp(k, "pack.window")) {
1679                 window = git_config_int(k, v);
1680                 return 0;
1681         }
1682         if (!strcmp(k, "pack.windowmemory")) {
1683                 window_memory_limit = git_config_ulong(k, v);
1684                 return 0;
1685         }
1686         if (!strcmp(k, "pack.depth")) {
1687                 depth = git_config_int(k, v);
1688                 return 0;
1689         }
1690         if (!strcmp(k, "pack.compression")) {
1691                 int level = git_config_int(k, v);
1692                 if (level == -1)
1693                         level = Z_DEFAULT_COMPRESSION;
1694                 else if (level < 0 || level > Z_BEST_COMPRESSION)
1695                         die("bad pack compression level %d", level);
1696                 pack_compression_level = level;
1697                 pack_compression_seen = 1;
1698                 return 0;
1699         }
1700         if (!strcmp(k, "pack.deltacachesize")) {
1701                 max_delta_cache_size = git_config_int(k, v);
1702                 return 0;
1703         }
1704         if (!strcmp(k, "pack.deltacachelimit")) {
1705                 cache_max_small_delta_size = git_config_int(k, v);
1706                 return 0;
1707         }
1708         return git_default_config(k, v);
1709 }
1710
1711 static void read_object_list_from_stdin(void)
1712 {
1713         char line[40 + 1 + PATH_MAX + 2];
1714         unsigned char sha1[20];
1715
1716         for (;;) {
1717                 if (!fgets(line, sizeof(line), stdin)) {
1718                         if (feof(stdin))
1719                                 break;
1720                         if (!ferror(stdin))
1721                                 die("fgets returned NULL, not EOF, not error!");
1722                         if (errno != EINTR)
1723                                 die("fgets: %s", strerror(errno));
1724                         clearerr(stdin);
1725                         continue;
1726                 }
1727                 if (line[0] == '-') {
1728                         if (get_sha1_hex(line+1, sha1))
1729                                 die("expected edge sha1, got garbage:\n %s",
1730                                     line);
1731                         add_preferred_base(sha1);
1732                         continue;
1733                 }
1734                 if (get_sha1_hex(line, sha1))
1735                         die("expected sha1, got garbage:\n %s", line);
1736
1737                 add_preferred_base_object(line+41);
1738                 add_object_entry(sha1, 0, line+41, 0);
1739         }
1740 }
1741
1742 static void show_commit(struct commit *commit)
1743 {
1744         add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
1745 }
1746
1747 static void show_object(struct object_array_entry *p)
1748 {
1749         add_preferred_base_object(p->name);
1750         add_object_entry(p->item->sha1, p->item->type, p->name, 0);
1751 }
1752
1753 static void show_edge(struct commit *commit)
1754 {
1755         add_preferred_base(commit->object.sha1);
1756 }
1757
1758 static void get_object_list(int ac, const char **av)
1759 {
1760         struct rev_info revs;
1761         char line[1000];
1762         int flags = 0;
1763
1764         init_revisions(&revs, NULL);
1765         save_commit_buffer = 0;
1766         track_object_refs = 0;
1767         setup_revisions(ac, av, &revs, NULL);
1768
1769         while (fgets(line, sizeof(line), stdin) != NULL) {
1770                 int len = strlen(line);
1771                 if (line[len - 1] == '\n')
1772                         line[--len] = 0;
1773                 if (!len)
1774                         break;
1775                 if (*line == '-') {
1776                         if (!strcmp(line, "--not")) {
1777                                 flags ^= UNINTERESTING;
1778                                 continue;
1779                         }
1780                         die("not a rev '%s'", line);
1781                 }
1782                 if (handle_revision_arg(line, &revs, flags, 1))
1783                         die("bad revision '%s'", line);
1784         }
1785
1786         prepare_revision_walk(&revs);
1787         mark_edges_uninteresting(revs.commits, &revs, show_edge);
1788         traverse_commit_list(&revs, show_commit, show_object);
1789 }
1790
1791 static int adjust_perm(const char *path, mode_t mode)
1792 {
1793         if (chmod(path, mode))
1794                 return -1;
1795         return adjust_shared_perm(path);
1796 }
1797
1798 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1799 {
1800         int use_internal_rev_list = 0;
1801         int thin = 0;
1802         uint32_t i;
1803         const char **rp_av;
1804         int rp_ac_alloc = 64;
1805         int rp_ac;
1806
1807         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1808
1809         rp_av[0] = "pack-objects";
1810         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1811         rp_ac = 2;
1812
1813         git_config(git_pack_config);
1814         if (!pack_compression_seen && core_compression_seen)
1815                 pack_compression_level = core_compression_level;
1816
1817         progress = isatty(2);
1818         for (i = 1; i < argc; i++) {
1819                 const char *arg = argv[i];
1820
1821                 if (*arg != '-')
1822                         break;
1823
1824                 if (!strcmp("--non-empty", arg)) {
1825                         non_empty = 1;
1826                         continue;
1827                 }
1828                 if (!strcmp("--local", arg)) {
1829                         local = 1;
1830                         continue;
1831                 }
1832                 if (!strcmp("--incremental", arg)) {
1833                         incremental = 1;
1834                         continue;
1835                 }
1836                 if (!prefixcmp(arg, "--compression=")) {
1837                         char *end;
1838                         int level = strtoul(arg+14, &end, 0);
1839                         if (!arg[14] || *end)
1840                                 usage(pack_usage);
1841                         if (level == -1)
1842                                 level = Z_DEFAULT_COMPRESSION;
1843                         else if (level < 0 || level > Z_BEST_COMPRESSION)
1844                                 die("bad pack compression level %d", level);
1845                         pack_compression_level = level;
1846                         continue;
1847                 }
1848                 if (!prefixcmp(arg, "--max-pack-size=")) {
1849                         char *end;
1850                         pack_size_limit = strtoul(arg+16, &end, 0) * 1024 * 1024;
1851                         if (!arg[16] || *end)
1852                                 usage(pack_usage);
1853                         continue;
1854                 }
1855                 if (!prefixcmp(arg, "--window=")) {
1856                         char *end;
1857                         window = strtoul(arg+9, &end, 0);
1858                         if (!arg[9] || *end)
1859                                 usage(pack_usage);
1860                         continue;
1861                 }
1862                 if (!prefixcmp(arg, "--window-memory=")) {
1863                         if (!git_parse_ulong(arg+16, &window_memory_limit))
1864                                 usage(pack_usage);
1865                         continue;
1866                 }
1867                 if (!prefixcmp(arg, "--depth=")) {
1868                         char *end;
1869                         depth = strtoul(arg+8, &end, 0);
1870                         if (!arg[8] || *end)
1871                                 usage(pack_usage);
1872                         continue;
1873                 }
1874                 if (!strcmp("--progress", arg)) {
1875                         progress = 1;
1876                         continue;
1877                 }
1878                 if (!strcmp("--all-progress", arg)) {
1879                         progress = 2;
1880                         continue;
1881                 }
1882                 if (!strcmp("-q", arg)) {
1883                         progress = 0;
1884                         continue;
1885                 }
1886                 if (!strcmp("--no-reuse-delta", arg)) {
1887                         no_reuse_delta = 1;
1888                         continue;
1889                 }
1890                 if (!strcmp("--no-reuse-object", arg)) {
1891                         no_reuse_object = no_reuse_delta = 1;
1892                         continue;
1893                 }
1894                 if (!strcmp("--delta-base-offset", arg)) {
1895                         allow_ofs_delta = 1;
1896                         continue;
1897                 }
1898                 if (!strcmp("--stdout", arg)) {
1899                         pack_to_stdout = 1;
1900                         continue;
1901                 }
1902                 if (!strcmp("--revs", arg)) {
1903                         use_internal_rev_list = 1;
1904                         continue;
1905                 }
1906                 if (!strcmp("--unpacked", arg) ||
1907                     !prefixcmp(arg, "--unpacked=") ||
1908                     !strcmp("--reflog", arg) ||
1909                     !strcmp("--all", arg)) {
1910                         use_internal_rev_list = 1;
1911                         if (rp_ac >= rp_ac_alloc - 1) {
1912                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
1913                                 rp_av = xrealloc(rp_av,
1914                                                  rp_ac_alloc * sizeof(*rp_av));
1915                         }
1916                         rp_av[rp_ac++] = arg;
1917                         continue;
1918                 }
1919                 if (!strcmp("--thin", arg)) {
1920                         use_internal_rev_list = 1;
1921                         thin = 1;
1922                         rp_av[1] = "--objects-edge";
1923                         continue;
1924                 }
1925                 if (!prefixcmp(arg, "--index-version=")) {
1926                         char *c;
1927                         pack_idx_default_version = strtoul(arg + 16, &c, 10);
1928                         if (pack_idx_default_version > 2)
1929                                 die("bad %s", arg);
1930                         if (*c == ',')
1931                                 pack_idx_off32_limit = strtoul(c+1, &c, 0);
1932                         if (*c || pack_idx_off32_limit & 0x80000000)
1933                                 die("bad %s", arg);
1934                         continue;
1935                 }
1936                 usage(pack_usage);
1937         }
1938
1939         /* Traditionally "pack-objects [options] base extra" failed;
1940          * we would however want to take refs parameter that would
1941          * have been given to upstream rev-list ourselves, which means
1942          * we somehow want to say what the base name is.  So the
1943          * syntax would be:
1944          *
1945          * pack-objects [options] base <refs...>
1946          *
1947          * in other words, we would treat the first non-option as the
1948          * base_name and send everything else to the internal revision
1949          * walker.
1950          */
1951
1952         if (!pack_to_stdout)
1953                 base_name = argv[i++];
1954
1955         if (pack_to_stdout != !base_name)
1956                 usage(pack_usage);
1957
1958         if (pack_to_stdout && pack_size_limit)
1959                 die("--max-pack-size cannot be used to build a pack for transfer.");
1960
1961         if (!pack_to_stdout && thin)
1962                 die("--thin cannot be used to build an indexable pack.");
1963
1964         prepare_packed_git();
1965
1966         if (progress)
1967                 start_progress(&progress_state, "Generating pack...",
1968                                "Counting objects: ", 0);
1969         if (!use_internal_rev_list)
1970                 read_object_list_from_stdin();
1971         else {
1972                 rp_av[rp_ac] = NULL;
1973                 get_object_list(rp_ac, rp_av);
1974         }
1975         if (progress) {
1976                 stop_progress(&progress_state);
1977                 fprintf(stderr, "Done counting %u objects.\n", nr_objects);
1978         }
1979
1980         if (non_empty && !nr_result)
1981                 return 0;
1982         if (progress && (nr_objects != nr_result))
1983                 fprintf(stderr, "Result has %u objects.\n", nr_result);
1984         if (nr_result)
1985                 prepare_pack(window, depth);
1986         write_pack_file();
1987         if (progress)
1988                 fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
1989                         written, written_delta, reused, reused_delta);
1990         return 0;
1991 }