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

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "attr.h"
   4 #include "object.h"
   5 #include "blob.h"
   6 #include "commit.h"
   7 #include "tag.h"
   8 #include "tree.h"
   9 #include "delta.h"
  10 #include "pack.h"
  11 #include "pack-revindex.h"
  12 #include "csum-file.h"
  13 #include "tree-walk.h"
  14 #include "diff.h"
  15 #include "revision.h"
  16 #include "list-objects.h"
  17 #include "progress.h"
  18 #include "refs.h"
  19 #include "thread-utils.h"
  20
  21 static const char *pack_usage[] = {
  22         "git pack-objects --stdout [options...] [< ref-list | < object-list]",
  23         "git pack-objects [options...] base-name [< ref-list | < object-list]",
  24         NULL
  25 };
  26
  27 struct object_entry {
  28         struct pack_idx_entry idx;
  29         unsigned long size;     /* uncompressed size */
  30         struct packed_git *in_pack;     /* already in pack */
  31         off_t in_pack_offset;
  32         struct object_entry *delta;     /* delta base object */
  33         struct object_entry *delta_child; /* deltified objects who bases me */
  34         struct object_entry *delta_sibling; /* other deltified objects who
  35                                              * uses the same base as me
  36                                              */
  37         void *delta_data;       /* cached delta (uncompressed) */
  38         unsigned long delta_size;       /* delta data size (uncompressed) */
  39         unsigned long z_delta_size;     /* delta data size (compressed) */
  40         unsigned int hash;      /* name hint hash */
  41         enum object_type type;
  42         enum object_type in_pack_type;  /* could be delta */
  43         unsigned char in_pack_header_size;
  44         unsigned char preferred_base; /* we do not pack this, but is available
  45                                        * to be used as the base object to delta
  46                                        * objects against.
  47                                        */
  48         unsigned char no_try_delta;
  49         unsigned char tagged; /* near the very tip of refs */
  50         unsigned char filled; /* assigned write-order */
  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 pack_idx_entry **written_list;
  61 static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  62
  63 static int non_empty;
  64 static int reuse_delta = 1, reuse_object = 1;
  65 static int keep_unreachable, unpack_unreachable, include_tag;
  66 static unsigned long unpack_unreachable_expiration;
  67 static int local;
  68 static int incremental;
  69 static int ignore_packed_keep;
  70 static int allow_ofs_delta;
  71 static struct pack_idx_option pack_idx_opts;
  72 static const char *base_name;
  73 static int progress = 1;
  74 static int window = 10;
  75 static unsigned long pack_size_limit;
  76 static int depth = 50;
  77 static int delta_search_threads;
  78 static int pack_to_stdout;
  79 static int num_preferred_base;
  80 static struct progress *progress_state;
  81 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  82 static int pack_compression_seen;
  83
  84 static unsigned long delta_cache_size = 0;
  85 static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  86 static unsigned long cache_max_small_delta_size = 1000;
  87
  88 static unsigned long window_memory_limit = 0;
  89
  90 /*
  91  * The object names in objects array are hashed with this hashtable,
  92  * to help looking up the entry by object name.
  93  * This hashtable is built after all the objects are seen.
  94  */
  95 static int *object_ix;
  96 static int object_ix_hashsz;
  97 static struct object_entry *locate_object_entry(const unsigned char *sha1);
  98
  99 /*
 100  * stats
 101  */
 102 static uint32_t written, written_delta;
 103 static uint32_t reused, reused_delta;
 104
 105
 106 static void *get_delta(struct object_entry *entry)
 107 {
 108         unsigned long size, base_size, delta_size;
 109         void *buf, *base_buf, *delta_buf;
 110         enum object_type type;
 111
 112         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 113         if (!buf)
 114                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 115         base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
 116         if (!base_buf)
 117                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 118         delta_buf = diff_delta(base_buf, base_size,
 119                                buf, size, &delta_size, 0);
 120         if (!delta_buf || delta_size != entry->delta_size)
 121                 die("delta size changed");
 122         free(buf);
 123         free(base_buf);
 124         return delta_buf;
 125 }
 126
 127 static unsigned long do_compress(void **pptr, unsigned long size)
 128 {
 129         git_zstream stream;
 130         void *in, *out;
 131         unsigned long maxsize;
 132
 133         memset(&stream, 0, sizeof(stream));
 134         git_deflate_init(&stream, pack_compression_level);
 135         maxsize = git_deflate_bound(&stream, size);
 136
 137         in = *pptr;
 138         out = xmalloc(maxsize);
 139         *pptr = out;
 140
 141         stream.next_in = in;
 142         stream.avail_in = size;
 143         stream.next_out = out;
 144         stream.avail_out = maxsize;
 145         while (git_deflate(&stream, Z_FINISH) == Z_OK)
 146                 ; /* nothing */
 147         git_deflate_end(&stream);
 148
 149         free(in);
 150         return stream.total_out;
 151 }
 152
 153 /*
 154  * we are going to reuse the existing object data as is.  make
 155  * sure it is not corrupt.
 156  */
 157 static int check_pack_inflate(struct packed_git *p,
 158                 struct pack_window **w_curs,
 159                 off_t offset,
 160                 off_t len,
 161                 unsigned long expect)
 162 {
 163         git_zstream stream;
 164         unsigned char fakebuf[4096], *in;
 165         int st;
 166
 167         memset(&stream, 0, sizeof(stream));
 168         git_inflate_init(&stream);
 169         do {
 170                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 171                 stream.next_in = in;
 172                 stream.next_out = fakebuf;
 173                 stream.avail_out = sizeof(fakebuf);
 174                 st = git_inflate(&stream, Z_FINISH);
 175                 offset += stream.next_in - in;
 176         } while (st == Z_OK || st == Z_BUF_ERROR);
 177         git_inflate_end(&stream);
 178         return (st == Z_STREAM_END &&
 179                 stream.total_out == expect &&
 180                 stream.total_in == len) ? 0 : -1;
 181 }
 182
 183 static void copy_pack_data(struct sha1file *f,
 184                 struct packed_git *p,
 185                 struct pack_window **w_curs,
 186                 off_t offset,
 187                 off_t len)
 188 {
 189         unsigned char *in;
 190         unsigned long avail;
 191
 192         while (len) {
 193                 in = use_pack(p, w_curs, offset, &avail);
 194                 if (avail > len)
 195                         avail = (unsigned long)len;
 196                 sha1write(f, in, avail);
 197                 offset += avail;
 198                 len -= avail;
 199         }
 200 }
 201
 202 /* Return 0 if we will bust the pack-size limit */
 203 static unsigned long write_no_reuse_object(struct sha1file *f, struct object_entry *entry,
 204                                            unsigned long limit, int usable_delta)
 205 {
 206         unsigned long size, datalen;
 207         unsigned char header[10], dheader[10];
 208         unsigned hdrlen;
 209         enum object_type type;
 210         void *buf;
 211
 212         if (!usable_delta) {
 213                 buf = read_sha1_file(entry->idx.sha1, &type, &size);
 214                 if (!buf)
 215                         die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 216                 /*
 217                  * make sure no cached delta data remains from a
 218                  * previous attempt before a pack split occurred.
 219                  */
 220                 free(entry->delta_data);
 221                 entry->delta_data = NULL;
 222                 entry->z_delta_size = 0;
 223         } else if (entry->delta_data) {
 224                 size = entry->delta_size;
 225                 buf = entry->delta_data;
 226                 entry->delta_data = NULL;
 227                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 228                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 229         } else {
 230                 buf = get_delta(entry);
 231                 size = entry->delta_size;
 232                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 233                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 234         }
 235
 236         if (entry->z_delta_size)
 237                 datalen = entry->z_delta_size;
 238         else
 239                 datalen = do_compress(&buf, size);
 240
 241         /*
 242          * The object header is a byte of 'type' followed by zero or
 243          * more bytes of length.
 244          */
 245         hdrlen = encode_in_pack_object_header(type, size, header);
 246
 247         if (type == OBJ_OFS_DELTA) {
 248                 /*
 249                  * Deltas with relative base contain an additional
 250                  * encoding of the relative offset for the delta
 251                  * base from this object's position in the pack.
 252                  */
 253                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 254                 unsigned pos = sizeof(dheader) - 1;
 255                 dheader[pos] = ofs & 127;
 256                 while (ofs >>= 7)
 257                         dheader[--pos] = 128 | (--ofs & 127);
 258                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 259                         free(buf);
 260                         return 0;
 261                 }
 262                 sha1write(f, header, hdrlen);
 263                 sha1write(f, dheader + pos, sizeof(dheader) - pos);
 264                 hdrlen += sizeof(dheader) - pos;
 265         } else if (type == OBJ_REF_DELTA) {
 266                 /*
 267                  * Deltas with a base reference contain
 268                  * an additional 20 bytes for the base sha1.
 269                  */
 270                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 271                         free(buf);
 272                         return 0;
 273                 }
 274                 sha1write(f, header, hdrlen);
 275                 sha1write(f, entry->delta->idx.sha1, 20);
 276                 hdrlen += 20;
 277         } else {
 278                 if (limit && hdrlen + datalen + 20 >= limit) {
 279                         free(buf);
 280                         return 0;
 281                 }
 282                 sha1write(f, header, hdrlen);
 283         }
 284         sha1write(f, buf, datalen);
 285         free(buf);
 286
 287         return hdrlen + datalen;
 288 }
 289
 290 /* Return 0 if we will bust the pack-size limit */
 291 static unsigned long write_reuse_object(struct sha1file *f, struct object_entry *entry,
 292                                         unsigned long limit, int usable_delta)
 293 {
 294         struct packed_git *p = entry->in_pack;
 295         struct pack_window *w_curs = NULL;
 296         struct revindex_entry *revidx;
 297         off_t offset;
 298         enum object_type type = entry->type;
 299         unsigned long datalen;
 300         unsigned char header[10], dheader[10];
 301         unsigned hdrlen;
 302
 303         if (entry->delta)
 304                 type = (allow_ofs_delta && entry->delta->idx.offset) ?
 305                         OBJ_OFS_DELTA : OBJ_REF_DELTA;
 306         hdrlen = encode_in_pack_object_header(type, entry->size, header);
 307
 308         offset = entry->in_pack_offset;
 309         revidx = find_pack_revindex(p, offset);
 310         datalen = revidx[1].offset - offset;
 311         if (!pack_to_stdout && p->index_version > 1 &&
 312             check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 313                 error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 314                 unuse_pack(&w_curs);
 315                 return write_no_reuse_object(f, entry, limit, usable_delta);
 316         }
 317
 318         offset += entry->in_pack_header_size;
 319         datalen -= entry->in_pack_header_size;
 320
 321         if (!pack_to_stdout && p->index_version == 1 &&
 322             check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 323                 error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 324                 unuse_pack(&w_curs);
 325                 return write_no_reuse_object(f, entry, limit, usable_delta);
 326         }
 327
 328         if (type == OBJ_OFS_DELTA) {
 329                 off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 330                 unsigned pos = sizeof(dheader) - 1;
 331                 dheader[pos] = ofs & 127;
 332                 while (ofs >>= 7)
 333                         dheader[--pos] = 128 | (--ofs & 127);
 334                 if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 335                         unuse_pack(&w_curs);
 336                         return 0;
 337                 }
 338                 sha1write(f, header, hdrlen);
 339                 sha1write(f, dheader + pos, sizeof(dheader) - pos);
 340                 hdrlen += sizeof(dheader) - pos;
 341                 reused_delta++;
 342         } else if (type == OBJ_REF_DELTA) {
 343                 if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 344                         unuse_pack(&w_curs);
 345                         return 0;
 346                 }
 347                 sha1write(f, header, hdrlen);
 348                 sha1write(f, entry->delta->idx.sha1, 20);
 349                 hdrlen += 20;
 350                 reused_delta++;
 351         } else {
 352                 if (limit && hdrlen + datalen + 20 >= limit) {
 353                         unuse_pack(&w_curs);
 354                         return 0;
 355                 }
 356                 sha1write(f, header, hdrlen);
 357         }
 358         copy_pack_data(f, p, &w_curs, offset, datalen);
 359         unuse_pack(&w_curs);
 360         reused++;
 361         return hdrlen + datalen;
 362 }
 363
 364 /* Return 0 if we will bust the pack-size limit */
 365 static unsigned long write_object(struct sha1file *f,
 366                                   struct object_entry *entry,
 367                                   off_t write_offset)
 368 {
 369         unsigned long limit, len;
 370         int usable_delta, to_reuse;
 371
 372         if (!pack_to_stdout)
 373                 crc32_begin(f);
 374
 375         /* apply size limit if limited packsize and not first object */
 376         if (!pack_size_limit || !nr_written)
 377                 limit = 0;
 378         else if (pack_size_limit <= write_offset)
 379                 /*
 380                  * the earlier object did not fit the limit; avoid
 381                  * mistaking this with unlimited (i.e. limit = 0).
 382                  */
 383                 limit = 1;
 384         else
 385                 limit = pack_size_limit - write_offset;
 386
 387         if (!entry->delta)
 388                 usable_delta = 0;       /* no delta */
 389         else if (!pack_size_limit)
 390                usable_delta = 1;        /* unlimited packfile */
 391         else if (entry->delta->idx.offset == (off_t)-1)
 392                 usable_delta = 0;       /* base was written to another pack */
 393         else if (entry->delta->idx.offset)
 394                 usable_delta = 1;       /* base already exists in this pack */
 395         else
 396                 usable_delta = 0;       /* base could end up in another pack */
 397
 398         if (!reuse_object)
 399                 to_reuse = 0;   /* explicit */
 400         else if (!entry->in_pack)
 401                 to_reuse = 0;   /* can't reuse what we don't have */
 402         else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
 403                                 /* check_object() decided it for us ... */
 404                 to_reuse = usable_delta;
 405                                 /* ... but pack split may override that */
 406         else if (entry->type != entry->in_pack_type)
 407                 to_reuse = 0;   /* pack has delta which is unusable */
 408         else if (entry->delta)
 409                 to_reuse = 0;   /* we want to pack afresh */
 410         else
 411                 to_reuse = 1;   /* we have it in-pack undeltified,
 412                                  * and we do not need to deltify it.
 413                                  */
 414
 415         if (!to_reuse)
 416                 len = write_no_reuse_object(f, entry, limit, usable_delta);
 417         else
 418                 len = write_reuse_object(f, entry, limit, usable_delta);
 419         if (!len)
 420                 return 0;
 421
 422         if (usable_delta)
 423                 written_delta++;
 424         written++;
 425         if (!pack_to_stdout)
 426                 entry->idx.crc32 = crc32_end(f);
 427         return len;
 428 }
 429
 430 enum write_one_status {
 431         WRITE_ONE_SKIP = -1, /* already written */
 432         WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 433         WRITE_ONE_WRITTEN = 1, /* normal */
 434         WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 435 };
 436
 437 static enum write_one_status write_one(struct sha1file *f,
 438                                        struct object_entry *e,
 439                                        off_t *offset)
 440 {
 441         unsigned long size;
 442         int recursing;
 443
 444         /*
 445          * we set offset to 1 (which is an impossible value) to mark
 446          * the fact that this object is involved in "write its base
 447          * first before writing a deltified object" recursion.
 448          */
 449         recursing = (e->idx.offset == 1);
 450         if (recursing) {
 451                 warning("recursive delta detected for object %s",
 452                         sha1_to_hex(e->idx.sha1));
 453                 return WRITE_ONE_RECURSIVE;
 454         } else if (e->idx.offset || e->preferred_base) {
 455                 /* offset is non zero if object is written already. */
 456                 return WRITE_ONE_SKIP;
 457         }
 458
 459         /* if we are deltified, write out base object first. */
 460         if (e->delta) {
 461                 e->idx.offset = 1; /* now recurse */
 462                 switch (write_one(f, e->delta, offset)) {
 463                 case WRITE_ONE_RECURSIVE:
 464                         /* we cannot depend on this one */
 465                         e->delta = NULL;
 466                         break;
 467                 default:
 468                         break;
 469                 case WRITE_ONE_BREAK:
 470                         e->idx.offset = recursing;
 471                         return WRITE_ONE_BREAK;
 472                 }
 473         }
 474
 475         e->idx.offset = *offset;
 476         size = write_object(f, e, *offset);
 477         if (!size) {
 478                 e->idx.offset = recursing;
 479                 return WRITE_ONE_BREAK;
 480         }
 481         written_list[nr_written++] = &e->idx;
 482
 483         /* make sure off_t is sufficiently large not to wrap */
 484         if (signed_add_overflows(*offset, size))
 485                 die("pack too large for current definition of off_t");
 486         *offset += size;
 487         return WRITE_ONE_WRITTEN;
 488 }
 489
 490 static int mark_tagged(const char *path, const unsigned char *sha1, int flag,
 491                        void *cb_data)
 492 {
 493         unsigned char peeled[20];
 494         struct object_entry *entry = locate_object_entry(sha1);
 495
 496         if (entry)
 497                 entry->tagged = 1;
 498         if (!peel_ref(path, peeled)) {
 499                 entry = locate_object_entry(peeled);
 500                 if (entry)
 501                         entry->tagged = 1;
 502         }
 503         return 0;
 504 }
 505
 506 static inline void add_to_write_order(struct object_entry **wo,
 507                                unsigned int *endp,
 508                                struct object_entry *e)
 509 {
 510         if (e->filled)
 511                 return;
 512         wo[(*endp)++] = e;
 513         e->filled = 1;
 514 }
 515
 516 static void add_descendants_to_write_order(struct object_entry **wo,
 517                                            unsigned int *endp,
 518                                            struct object_entry *e)
 519 {
 520         int add_to_order = 1;
 521         while (e) {
 522                 if (add_to_order) {
 523                         struct object_entry *s;
 524                         /* add this node... */
 525                         add_to_write_order(wo, endp, e);
 526                         /* all its siblings... */
 527                         for (s = e->delta_sibling; s; s = s->delta_sibling) {
 528                                 add_to_write_order(wo, endp, s);
 529                         }
 530                 }
 531                 /* drop down a level to add left subtree nodes if possible */
 532                 if (e->delta_child) {
 533                         add_to_order = 1;
 534                         e = e->delta_child;
 535                 } else {
 536                         add_to_order = 0;
 537                         /* our sibling might have some children, it is next */
 538                         if (e->delta_sibling) {
 539                                 e = e->delta_sibling;
 540                                 continue;
 541                         }
 542                         /* go back to our parent node */
 543                         e = e->delta;
 544                         while (e && !e->delta_sibling) {
 545                                 /* we're on the right side of a subtree, keep
 546                                  * going up until we can go right again */
 547                                 e = e->delta;
 548                         }
 549                         if (!e) {
 550                                 /* done- we hit our original root node */
 551                                 return;
 552                         }
 553                         /* pass it off to sibling at this level */
 554                         e = e->delta_sibling;
 555                 }
 556         };
 557 }
 558
 559 static void add_family_to_write_order(struct object_entry **wo,
 560                                       unsigned int *endp,
 561                                       struct object_entry *e)
 562 {
 563         struct object_entry *root;
 564
 565         for (root = e; root->delta; root = root->delta)
 566                 ; /* nothing */
 567         add_descendants_to_write_order(wo, endp, root);
 568 }
 569
 570 static struct object_entry **compute_write_order(void)
 571 {
 572         unsigned int i, wo_end, last_untagged;
 573
 574         struct object_entry **wo = xmalloc(nr_objects * sizeof(*wo));
 575
 576         for (i = 0; i < nr_objects; i++) {
 577                 objects[i].tagged = 0;
 578                 objects[i].filled = 0;
 579                 objects[i].delta_child = NULL;
 580                 objects[i].delta_sibling = NULL;
 581         }
 582
 583         /*
 584          * Fully connect delta_child/delta_sibling network.
 585          * Make sure delta_sibling is sorted in the original
 586          * recency order.
 587          */
 588         for (i = nr_objects; i > 0;) {
 589                 struct object_entry *e = &objects[--i];
 590                 if (!e->delta)
 591                         continue;
 592                 /* Mark me as the first child */
 593                 e->delta_sibling = e->delta->delta_child;
 594                 e->delta->delta_child = e;
 595         }
 596
 597         /*
 598          * Mark objects that are at the tip of tags.
 599          */
 600         for_each_tag_ref(mark_tagged, NULL);
 601
 602         /*
 603          * Give the objects in the original recency order until
 604          * we see a tagged tip.
 605          */
 606         for (i = wo_end = 0; i < nr_objects; i++) {
 607                 if (objects[i].tagged)
 608                         break;
 609                 add_to_write_order(wo, &wo_end, &objects[i]);
 610         }
 611         last_untagged = i;
 612
 613         /*
 614          * Then fill all the tagged tips.
 615          */
 616         for (; i < nr_objects; i++) {
 617                 if (objects[i].tagged)
 618                         add_to_write_order(wo, &wo_end, &objects[i]);
 619         }
 620
 621         /*
 622          * And then all remaining commits and tags.
 623          */
 624         for (i = last_untagged; i < nr_objects; i++) {
 625                 if (objects[i].type != OBJ_COMMIT &&
 626                     objects[i].type != OBJ_TAG)
 627                         continue;
 628                 add_to_write_order(wo, &wo_end, &objects[i]);
 629         }
 630
 631         /*
 632          * And then all the trees.
 633          */
 634         for (i = last_untagged; i < nr_objects; i++) {
 635                 if (objects[i].type != OBJ_TREE)
 636                         continue;
 637                 add_to_write_order(wo, &wo_end, &objects[i]);
 638         }
 639
 640         /*
 641          * Finally all the rest in really tight order
 642          */
 643         for (i = last_untagged; i < nr_objects; i++) {
 644                 if (!objects[i].filled)
 645                         add_family_to_write_order(wo, &wo_end, &objects[i]);
 646         }
 647
 648         if (wo_end != nr_objects)
 649                 die("ordered %u objects, expected %"PRIu32, wo_end, nr_objects);
 650
 651         return wo;
 652 }
 653
 654 static void write_pack_file(void)
 655 {
 656         uint32_t i = 0, j;
 657         struct sha1file *f;
 658         off_t offset;
 659         uint32_t nr_remaining = nr_result;
 660         time_t last_mtime = 0;
 661         struct object_entry **write_order;
 662
 663         if (progress > pack_to_stdout)
 664                 progress_state = start_progress("Writing objects", nr_result);
 665         written_list = xmalloc(nr_objects * sizeof(*written_list));
 666         write_order = compute_write_order();
 667
 668         do {
 669                 unsigned char sha1[20];
 670                 char *pack_tmp_name = NULL;
 671
 672                 if (pack_to_stdout)
 673                         f = sha1fd_throughput(1, "<stdout>", progress_state);
 674                 else
 675                         f = create_tmp_packfile(&pack_tmp_name);
 676
 677                 offset = write_pack_header(f, nr_remaining);
 678                 if (!offset)
 679                         die_errno("unable to write pack header");
 680                 nr_written = 0;
 681                 for (; i < nr_objects; i++) {
 682                         struct object_entry *e = write_order[i];
 683                         if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 684                                 break;
 685                         display_progress(progress_state, written);
 686                 }
 687
 688                 /*
 689                  * Did we write the wrong # entries in the header?
 690                  * If so, rewrite it like in fast-import
 691                  */
 692                 if (pack_to_stdout) {
 693                         sha1close(f, sha1, CSUM_CLOSE);
 694                 } else if (nr_written == nr_remaining) {
 695                         sha1close(f, sha1, CSUM_FSYNC);
 696                 } else {
 697                         int fd = sha1close(f, sha1, 0);
 698                         fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 699                                                  nr_written, sha1, offset);
 700                         close(fd);
 701                 }
 702
 703                 if (!pack_to_stdout) {
 704                         struct stat st;
 705                         char tmpname[PATH_MAX];
 706
 707                         /*
 708                          * Packs are runtime accessed in their mtime
 709                          * order since newer packs are more likely to contain
 710                          * younger objects.  So if we are creating multiple
 711                          * packs then we should modify the mtime of later ones
 712                          * to preserve this property.
 713                          */
 714                         if (stat(pack_tmp_name, &st) < 0) {
 715                                 warning("failed to stat %s: %s",
 716                                         pack_tmp_name, strerror(errno));
 717                         } else if (!last_mtime) {
 718                                 last_mtime = st.st_mtime;
 719                         } else {
 720                                 struct utimbuf utb;
 721                                 utb.actime = st.st_atime;
 722                                 utb.modtime = --last_mtime;
 723                                 if (utime(pack_tmp_name, &utb) < 0)
 724                                         warning("failed utime() on %s: %s",
 725                                                 tmpname, strerror(errno));
 726                         }
 727
 728                         /* Enough space for "-<sha-1>.pack"? */
 729                         if (sizeof(tmpname) <= strlen(base_name) + 50)
 730                                 die("pack base name '%s' too long", base_name);
 731                         snprintf(tmpname, sizeof(tmpname), "%s-", base_name);
 732                         finish_tmp_packfile(tmpname, pack_tmp_name,
 733                                             written_list, nr_written,
 734                                             &pack_idx_opts, sha1);
 735                         free(pack_tmp_name);
 736                         puts(sha1_to_hex(sha1));
 737                 }
 738
 739                 /* mark written objects as written to previous pack */
 740                 for (j = 0; j < nr_written; j++) {
 741                         written_list[j]->offset = (off_t)-1;
 742                 }
 743                 nr_remaining -= nr_written;
 744         } while (nr_remaining && i < nr_objects);
 745
 746         free(written_list);
 747         free(write_order);
 748         stop_progress(&progress_state);
 749         if (written != nr_result)
 750                 die("wrote %"PRIu32" objects while expecting %"PRIu32,
 751                         written, nr_result);
 752 }
 753
 754 static int locate_object_entry_hash(const unsigned char *sha1)
 755 {
 756         int i;
 757         unsigned int ui;
 758         memcpy(&ui, sha1, sizeof(unsigned int));
 759         i = ui % object_ix_hashsz;
 760         while (0 < object_ix[i]) {
 761                 if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 762                         return i;
 763                 if (++i == object_ix_hashsz)
 764                         i = 0;
 765         }
 766         return -1 - i;
 767 }
 768
 769 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 770 {
 771         int i;
 772
 773         if (!object_ix_hashsz)
 774                 return NULL;
 775
 776         i = locate_object_entry_hash(sha1);
 777         if (0 <= i)
 778                 return &objects[object_ix[i]-1];
 779         return NULL;
 780 }
 781
 782 static void rehash_objects(void)
 783 {
 784         uint32_t i;
 785         struct object_entry *oe;
 786
 787         object_ix_hashsz = nr_objects * 3;
 788         if (object_ix_hashsz < 1024)
 789                 object_ix_hashsz = 1024;
 790         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 791         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 792         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 793                 int ix = locate_object_entry_hash(oe->idx.sha1);
 794                 if (0 <= ix)
 795                         continue;
 796                 ix = -1 - ix;
 797                 object_ix[ix] = i + 1;
 798         }
 799 }
 800
 801 static unsigned name_hash(const char *name)
 802 {
 803         unsigned c, hash = 0;
 804
 805         if (!name)
 806                 return 0;
 807
 808         /*
 809          * This effectively just creates a sortable number from the
 810          * last sixteen non-whitespace characters. Last characters
 811          * count "most", so things that end in ".c" sort together.
 812          */
 813         while ((c = *name++) != 0) {
 814                 if (isspace(c))
 815                         continue;
 816                 hash = (hash >> 2) + (c << 24);
 817         }
 818         return hash;
 819 }
 820
 821 static void setup_delta_attr_check(struct git_attr_check *check)
 822 {
 823         static struct git_attr *attr_delta;
 824
 825         if (!attr_delta)
 826                 attr_delta = git_attr("delta");
 827
 828         check[0].attr = attr_delta;
 829 }
 830
 831 static int no_try_delta(const char *path)
 832 {
 833         struct git_attr_check check[1];
 834
 835         setup_delta_attr_check(check);
 836         if (git_check_attr(path, ARRAY_SIZE(check), check))
 837                 return 0;
 838         if (ATTR_FALSE(check->value))
 839                 return 1;
 840         return 0;
 841 }
 842
 843 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 844                             const char *name, int exclude)
 845 {
 846         struct object_entry *entry;
 847         struct packed_git *p, *found_pack = NULL;
 848         off_t found_offset = 0;
 849         int ix;
 850         unsigned hash = name_hash(name);
 851
 852         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 853         if (ix >= 0) {
 854                 if (exclude) {
 855                         entry = objects + object_ix[ix] - 1;
 856                         if (!entry->preferred_base)
 857                                 nr_result--;
 858                         entry->preferred_base = 1;
 859                 }
 860                 return 0;
 861         }
 862
 863         if (!exclude && local && has_loose_object_nonlocal(sha1))
 864                 return 0;
 865
 866         for (p = packed_git; p; p = p->next) {
 867                 off_t offset = find_pack_entry_one(sha1, p);
 868                 if (offset) {
 869                         if (!found_pack) {
 870                                 if (!is_pack_valid(p)) {
 871                                         warning("packfile %s cannot be accessed", p->pack_name);
 872                                         continue;
 873                                 }
 874                                 found_offset = offset;
 875                                 found_pack = p;
 876                         }
 877                         if (exclude)
 878                                 break;
 879                         if (incremental)
 880                                 return 0;
 881                         if (local && !p->pack_local)
 882                                 return 0;
 883                         if (ignore_packed_keep && p->pack_local && p->pack_keep)
 884                                 return 0;
 885                 }
 886         }
 887
 888         if (nr_objects >= nr_alloc) {
 889                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 890                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 891         }
 892
 893         entry = objects + nr_objects++;
 894         memset(entry, 0, sizeof(*entry));
 895         hashcpy(entry->idx.sha1, sha1);
 896         entry->hash = hash;
 897         if (type)
 898                 entry->type = type;
 899         if (exclude)
 900                 entry->preferred_base = 1;
 901         else
 902                 nr_result++;
 903         if (found_pack) {
 904                 entry->in_pack = found_pack;
 905                 entry->in_pack_offset = found_offset;
 906         }
 907
 908         if (object_ix_hashsz * 3 <= nr_objects * 4)
 909                 rehash_objects();
 910         else
 911                 object_ix[-1 - ix] = nr_objects;
 912
 913         display_progress(progress_state, nr_objects);
 914
 915         if (name && no_try_delta(name))
 916                 entry->no_try_delta = 1;
 917
 918         return 1;
 919 }
 920
 921 struct pbase_tree_cache {
 922         unsigned char sha1[20];
 923         int ref;
 924         int temporary;
 925         void *tree_data;
 926         unsigned long tree_size;
 927 };
 928
 929 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 930 static int pbase_tree_cache_ix(const unsigned char *sha1)
 931 {
 932         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 933 }
 934 static int pbase_tree_cache_ix_incr(int ix)
 935 {
 936         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 937 }
 938
 939 static struct pbase_tree {
 940         struct pbase_tree *next;
 941         /* This is a phony "cache" entry; we are not
 942          * going to evict it nor find it through _get()
 943          * mechanism -- this is for the toplevel node that
 944          * would almost always change with any commit.
 945          */
 946         struct pbase_tree_cache pcache;
 947 } *pbase_tree;
 948
 949 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 950 {
 951         struct pbase_tree_cache *ent, *nent;
 952         void *data;
 953         unsigned long size;
 954         enum object_type type;
 955         int neigh;
 956         int my_ix = pbase_tree_cache_ix(sha1);
 957         int available_ix = -1;
 958
 959         /* pbase-tree-cache acts as a limited hashtable.
 960          * your object will be found at your index or within a few
 961          * slots after that slot if it is cached.
 962          */
 963         for (neigh = 0; neigh < 8; neigh++) {
 964                 ent = pbase_tree_cache[my_ix];
 965                 if (ent && !hashcmp(ent->sha1, sha1)) {
 966                         ent->ref++;
 967                         return ent;
 968                 }
 969                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 970                          ((0 <= available_ix) &&
 971                           (!ent && pbase_tree_cache[available_ix])))
 972                         available_ix = my_ix;
 973                 if (!ent)
 974                         break;
 975                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 976         }
 977
 978         /* Did not find one.  Either we got a bogus request or
 979          * we need to read and perhaps cache.
 980          */
 981         data = read_sha1_file(sha1, &type, &size);
 982         if (!data)
 983                 return NULL;
 984         if (type != OBJ_TREE) {
 985                 free(data);
 986                 return NULL;
 987         }
 988
 989         /* We need to either cache or return a throwaway copy */
 990
 991         if (available_ix < 0)
 992                 ent = NULL;
 993         else {
 994                 ent = pbase_tree_cache[available_ix];
 995                 my_ix = available_ix;
 996         }
 997
 998         if (!ent) {
 999                 nent = xmalloc(sizeof(*nent));
1000                 nent->temporary = (available_ix < 0);
1001         }
1002         else {
1003                 /* evict and reuse */
1004                 free(ent->tree_data);
1005                 nent = ent;
1006         }
1007         hashcpy(nent->sha1, sha1);
1008         nent->tree_data = data;
1009         nent->tree_size = size;
1010         nent->ref = 1;
1011         if (!nent->temporary)
1012                 pbase_tree_cache[my_ix] = nent;
1013         return nent;
1014 }
1015
1016 static void pbase_tree_put(struct pbase_tree_cache *cache)
1017 {
1018         if (!cache->temporary) {
1019                 cache->ref--;
1020                 return;
1021         }
1022         free(cache->tree_data);
1023         free(cache);
1024 }
1025
1026 static int name_cmp_len(const char *name)
1027 {
1028         int i;
1029         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1030                 ;
1031         return i;
1032 }
1033
1034 static void add_pbase_object(struct tree_desc *tree,
1035                              const char *name,
1036                              int cmplen,
1037                              const char *fullname)
1038 {
1039         struct name_entry entry;
1040         int cmp;
1041
1042         while (tree_entry(tree,&entry)) {
1043                 if (S_ISGITLINK(entry.mode))
1044                         continue;
1045                 cmp = tree_entry_len(&entry) != cmplen ? 1 :
1046                       memcmp(name, entry.path, cmplen);
1047                 if (cmp > 0)
1048                         continue;
1049                 if (cmp < 0)
1050                         return;
1051                 if (name[cmplen] != '/') {
1052                         add_object_entry(entry.sha1,
1053                                          object_type(entry.mode),
1054                                          fullname, 1);
1055                         return;
1056                 }
1057                 if (S_ISDIR(entry.mode)) {
1058                         struct tree_desc sub;
1059                         struct pbase_tree_cache *tree;
1060                         const char *down = name+cmplen+1;
1061                         int downlen = name_cmp_len(down);
1062
1063                         tree = pbase_tree_get(entry.sha1);
1064                         if (!tree)
1065                                 return;
1066                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1067
1068                         add_pbase_object(&sub, down, downlen, fullname);
1069                         pbase_tree_put(tree);
1070                 }
1071         }
1072 }
1073
1074 static unsigned *done_pbase_paths;
1075 static int done_pbase_paths_num;
1076 static int done_pbase_paths_alloc;
1077 static int done_pbase_path_pos(unsigned hash)
1078 {
1079         int lo = 0;
1080         int hi = done_pbase_paths_num;
1081         while (lo < hi) {
1082                 int mi = (hi + lo) / 2;
1083                 if (done_pbase_paths[mi] == hash)
1084                         return mi;
1085                 if (done_pbase_paths[mi] < hash)
1086                         hi = mi;
1087                 else
1088                         lo = mi + 1;
1089         }
1090         return -lo-1;
1091 }
1092
1093 static int check_pbase_path(unsigned hash)
1094 {
1095         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1096         if (0 <= pos)
1097                 return 1;
1098         pos = -pos - 1;
1099         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1100                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1101                 done_pbase_paths = xrealloc(done_pbase_paths,
1102                                             done_pbase_paths_alloc *
1103                                             sizeof(unsigned));
1104         }
1105         done_pbase_paths_num++;
1106         if (pos < done_pbase_paths_num)
1107                 memmove(done_pbase_paths + pos + 1,
1108                         done_pbase_paths + pos,
1109                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1110         done_pbase_paths[pos] = hash;
1111         return 0;
1112 }
1113
1114 static void add_preferred_base_object(const char *name)
1115 {
1116         struct pbase_tree *it;
1117         int cmplen;
1118         unsigned hash = name_hash(name);
1119
1120         if (!num_preferred_base || check_pbase_path(hash))
1121                 return;
1122
1123         cmplen = name_cmp_len(name);
1124         for (it = pbase_tree; it; it = it->next) {
1125                 if (cmplen == 0) {
1126                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1127                 }
1128                 else {
1129                         struct tree_desc tree;
1130                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1131                         add_pbase_object(&tree, name, cmplen, name);
1132                 }
1133         }
1134 }
1135
1136 static void add_preferred_base(unsigned char *sha1)
1137 {
1138         struct pbase_tree *it;
1139         void *data;
1140         unsigned long size;
1141         unsigned char tree_sha1[20];
1142
1143         if (window <= num_preferred_base++)
1144                 return;
1145
1146         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1147         if (!data)
1148                 return;
1149
1150         for (it = pbase_tree; it; it = it->next) {
1151                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1152                         free(data);
1153                         return;
1154                 }
1155         }
1156
1157         it = xcalloc(1, sizeof(*it));
1158         it->next = pbase_tree;
1159         pbase_tree = it;
1160
1161         hashcpy(it->pcache.sha1, tree_sha1);
1162         it->pcache.tree_data = data;
1163         it->pcache.tree_size = size;
1164 }
1165
1166 static void cleanup_preferred_base(void)
1167 {
1168         struct pbase_tree *it;
1169         unsigned i;
1170
1171         it = pbase_tree;
1172         pbase_tree = NULL;
1173         while (it) {
1174                 struct pbase_tree *this = it;
1175                 it = this->next;
1176                 free(this->pcache.tree_data);
1177                 free(this);
1178         }
1179
1180         for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1181                 if (!pbase_tree_cache[i])
1182                         continue;
1183                 free(pbase_tree_cache[i]->tree_data);
1184                 free(pbase_tree_cache[i]);
1185                 pbase_tree_cache[i] = NULL;
1186         }
1187
1188         free(done_pbase_paths);
1189         done_pbase_paths = NULL;
1190         done_pbase_paths_num = done_pbase_paths_alloc = 0;
1191 }
1192
1193 static void check_object(struct object_entry *entry)
1194 {
1195         if (entry->in_pack) {
1196                 struct packed_git *p = entry->in_pack;
1197                 struct pack_window *w_curs = NULL;
1198                 const unsigned char *base_ref = NULL;
1199                 struct object_entry *base_entry;
1200                 unsigned long used, used_0;
1201                 unsigned long avail;
1202                 off_t ofs;
1203                 unsigned char *buf, c;
1204
1205                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1206
1207                 /*
1208                  * We want in_pack_type even if we do not reuse delta
1209                  * since non-delta representations could still be reused.
1210                  */
1211                 used = unpack_object_header_buffer(buf, avail,
1212                                                    &entry->in_pack_type,
1213                                                    &entry->size);
1214                 if (used == 0)
1215                         goto give_up;
1216
1217                 /*
1218                  * Determine if this is a delta and if so whether we can
1219                  * reuse it or not.  Otherwise let's find out as cheaply as
1220                  * possible what the actual type and size for this object is.
1221                  */
1222                 switch (entry->in_pack_type) {
1223                 default:
1224                         /* Not a delta hence we've already got all we need. */
1225                         entry->type = entry->in_pack_type;
1226                         entry->in_pack_header_size = used;
1227                         if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1228                                 goto give_up;
1229                         unuse_pack(&w_curs);
1230                         return;
1231                 case OBJ_REF_DELTA:
1232                         if (reuse_delta && !entry->preferred_base)
1233                                 base_ref = use_pack(p, &w_curs,
1234                                                 entry->in_pack_offset + used, NULL);
1235                         entry->in_pack_header_size = used + 20;
1236                         break;
1237                 case OBJ_OFS_DELTA:
1238                         buf = use_pack(p, &w_curs,
1239                                        entry->in_pack_offset + used, NULL);
1240                         used_0 = 0;
1241                         c = buf[used_0++];
1242                         ofs = c & 127;
1243                         while (c & 128) {
1244                                 ofs += 1;
1245                                 if (!ofs || MSB(ofs, 7)) {
1246                                         error("delta base offset overflow in pack for %s",
1247                                               sha1_to_hex(entry->idx.sha1));
1248                                         goto give_up;
1249                                 }
1250                                 c = buf[used_0++];
1251                                 ofs = (ofs << 7) + (c & 127);
1252                         }
1253                         ofs = entry->in_pack_offset - ofs;
1254                         if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1255                                 error("delta base offset out of bound for %s",
1256                                       sha1_to_hex(entry->idx.sha1));
1257                                 goto give_up;
1258                         }
1259                         if (reuse_delta && !entry->preferred_base) {
1260                                 struct revindex_entry *revidx;
1261                                 revidx = find_pack_revindex(p, ofs);
1262                                 if (!revidx)
1263                                         goto give_up;
1264                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1265                         }
1266                         entry->in_pack_header_size = used + used_0;
1267                         break;
1268                 }
1269
1270                 if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1271                         /*
1272                          * If base_ref was set above that means we wish to
1273                          * reuse delta data, and we even found that base
1274                          * in the list of objects we want to pack. Goodie!
1275                          *
1276                          * Depth value does not matter - find_deltas() will
1277                          * never consider reused delta as the base object to
1278                          * deltify other objects against, in order to avoid
1279                          * circular deltas.
1280                          */
1281                         entry->type = entry->in_pack_type;
1282                         entry->delta = base_entry;
1283                         entry->delta_size = entry->size;
1284                         entry->delta_sibling = base_entry->delta_child;
1285                         base_entry->delta_child = entry;
1286                         unuse_pack(&w_curs);
1287                         return;
1288                 }
1289
1290                 if (entry->type) {
1291                         /*
1292                          * This must be a delta and we already know what the
1293                          * final object type is.  Let's extract the actual
1294                          * object size from the delta header.
1295                          */
1296                         entry->size = get_size_from_delta(p, &w_curs,
1297                                         entry->in_pack_offset + entry->in_pack_header_size);
1298                         if (entry->size == 0)
1299                                 goto give_up;
1300                         unuse_pack(&w_curs);
1301                         return;
1302                 }
1303
1304                 /*
1305                  * No choice but to fall back to the recursive delta walk
1306                  * with sha1_object_info() to find about the object type
1307                  * at this point...
1308                  */
1309                 give_up:
1310                 unuse_pack(&w_curs);
1311         }
1312
1313         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1314         /*
1315          * The error condition is checked in prepare_pack().  This is
1316          * to permit a missing preferred base object to be ignored
1317          * as a preferred base.  Doing so can result in a larger
1318          * pack file, but the transfer will still take place.
1319          */
1320 }
1321
1322 static int pack_offset_sort(const void *_a, const void *_b)
1323 {
1324         const struct object_entry *a = *(struct object_entry **)_a;
1325         const struct object_entry *b = *(struct object_entry **)_b;
1326
1327         /* avoid filesystem trashing with loose objects */
1328         if (!a->in_pack && !b->in_pack)
1329                 return hashcmp(a->idx.sha1, b->idx.sha1);
1330
1331         if (a->in_pack < b->in_pack)
1332                 return -1;
1333         if (a->in_pack > b->in_pack)
1334                 return 1;
1335         return a->in_pack_offset < b->in_pack_offset ? -1 :
1336                         (a->in_pack_offset > b->in_pack_offset);
1337 }
1338
1339 static void get_object_details(void)
1340 {
1341         uint32_t i;
1342         struct object_entry **sorted_by_offset;
1343
1344         sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1345         for (i = 0; i < nr_objects; i++)
1346                 sorted_by_offset[i] = objects + i;
1347         qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1348
1349         for (i = 0; i < nr_objects; i++) {
1350                 struct object_entry *entry = sorted_by_offset[i];
1351                 check_object(entry);
1352                 if (big_file_threshold < entry->size)
1353                         entry->no_try_delta = 1;
1354         }
1355
1356         free(sorted_by_offset);
1357 }
1358
1359 /*
1360  * We search for deltas in a list sorted by type, by filename hash, and then
1361  * by size, so that we see progressively smaller and smaller files.
1362  * That's because we prefer deltas to be from the bigger file
1363  * to the smaller -- deletes are potentially cheaper, but perhaps
1364  * more importantly, the bigger file is likely the more recent
1365  * one.  The deepest deltas are therefore the oldest objects which are
1366  * less susceptible to be accessed often.
1367  */
1368 static int type_size_sort(const void *_a, const void *_b)
1369 {
1370         const struct object_entry *a = *(struct object_entry **)_a;
1371         const struct object_entry *b = *(struct object_entry **)_b;
1372
1373         if (a->type > b->type)
1374                 return -1;
1375         if (a->type < b->type)
1376                 return 1;
1377         if (a->hash > b->hash)
1378                 return -1;
1379         if (a->hash < b->hash)
1380                 return 1;
1381         if (a->preferred_base > b->preferred_base)
1382                 return -1;
1383         if (a->preferred_base < b->preferred_base)
1384                 return 1;
1385         if (a->size > b->size)
1386                 return -1;
1387         if (a->size < b->size)
1388                 return 1;
1389         return a < b ? -1 : (a > b);  /* newest first */
1390 }
1391
1392 struct unpacked {
1393         struct object_entry *entry;
1394         void *data;
1395         struct delta_index *index;
1396         unsigned depth;
1397 };
1398
1399 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1400                            unsigned long delta_size)
1401 {
1402         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1403                 return 0;
1404
1405         if (delta_size < cache_max_small_delta_size)
1406                 return 1;
1407
1408         /* cache delta, if objects are large enough compared to delta size */
1409         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1410                 return 1;
1411
1412         return 0;
1413 }
1414
1415 #ifndef NO_PTHREADS
1416
1417 static pthread_mutex_t read_mutex;
1418 #define read_lock()             pthread_mutex_lock(&read_mutex)
1419 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1420
1421 static pthread_mutex_t cache_mutex;
1422 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1423 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1424
1425 static pthread_mutex_t progress_mutex;
1426 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1427 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1428
1429 #else
1430
1431 #define read_lock()             (void)0
1432 #define read_unlock()           (void)0
1433 #define cache_lock()            (void)0
1434 #define cache_unlock()          (void)0
1435 #define progress_lock()         (void)0
1436 #define progress_unlock()       (void)0
1437
1438 #endif
1439
1440 static int try_delta(struct unpacked *trg, struct unpacked *src,
1441                      unsigned max_depth, unsigned long *mem_usage)
1442 {
1443         struct object_entry *trg_entry = trg->entry;
1444         struct object_entry *src_entry = src->entry;
1445         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1446         unsigned ref_depth;
1447         enum object_type type;
1448         void *delta_buf;
1449
1450         /* Don't bother doing diffs between different types */
1451         if (trg_entry->type != src_entry->type)
1452                 return -1;
1453
1454         /*
1455          * We do not bother to try a delta that we discarded on an
1456          * earlier try, but only when reusing delta data.  Note that
1457          * src_entry that is marked as the preferred_base should always
1458          * be considered, as even if we produce a suboptimal delta against
1459          * it, we will still save the transfer cost, as we already know
1460          * the other side has it and we won't send src_entry at all.
1461          */
1462         if (reuse_delta && trg_entry->in_pack &&
1463             trg_entry->in_pack == src_entry->in_pack &&
1464             !src_entry->preferred_base &&
1465             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1466             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1467                 return 0;
1468
1469         /* Let's not bust the allowed depth. */
1470         if (src->depth >= max_depth)
1471                 return 0;
1472
1473         /* Now some size filtering heuristics. */
1474         trg_size = trg_entry->size;
1475         if (!trg_entry->delta) {
1476                 max_size = trg_size/2 - 20;
1477                 ref_depth = 1;
1478         } else {
1479                 max_size = trg_entry->delta_size;
1480                 ref_depth = trg->depth;
1481         }
1482         max_size = (uint64_t)max_size * (max_depth - src->depth) /
1483                                                 (max_depth - ref_depth + 1);
1484         if (max_size == 0)
1485                 return 0;
1486         src_size = src_entry->size;
1487         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1488         if (sizediff >= max_size)
1489                 return 0;
1490         if (trg_size < src_size / 32)
1491                 return 0;
1492
1493         /* Load data if not already done */
1494         if (!trg->data) {
1495                 read_lock();
1496                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1497                 read_unlock();
1498                 if (!trg->data)
1499                         die("object %s cannot be read",
1500                             sha1_to_hex(trg_entry->idx.sha1));
1501                 if (sz != trg_size)
1502                         die("object %s inconsistent object length (%lu vs %lu)",
1503                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1504                 *mem_usage += sz;
1505         }
1506         if (!src->data) {
1507                 read_lock();
1508                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1509                 read_unlock();
1510                 if (!src->data) {
1511                         if (src_entry->preferred_base) {
1512                                 static int warned = 0;
1513                                 if (!warned++)
1514                                         warning("object %s cannot be read",
1515                                                 sha1_to_hex(src_entry->idx.sha1));
1516                                 /*
1517                                  * Those objects are not included in the
1518                                  * resulting pack.  Be resilient and ignore
1519                                  * them if they can't be read, in case the
1520                                  * pack could be created nevertheless.
1521                                  */
1522                                 return 0;
1523                         }
1524                         die("object %s cannot be read",
1525                             sha1_to_hex(src_entry->idx.sha1));
1526                 }
1527                 if (sz != src_size)
1528                         die("object %s inconsistent object length (%lu vs %lu)",
1529                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1530                 *mem_usage += sz;
1531         }
1532         if (!src->index) {
1533                 src->index = create_delta_index(src->data, src_size);
1534                 if (!src->index) {
1535                         static int warned = 0;
1536                         if (!warned++)
1537                                 warning("suboptimal pack - out of memory");
1538                         return 0;
1539                 }
1540                 *mem_usage += sizeof_delta_index(src->index);
1541         }
1542
1543         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1544         if (!delta_buf)
1545                 return 0;
1546
1547         if (trg_entry->delta) {
1548                 /* Prefer only shallower same-sized deltas. */
1549                 if (delta_size == trg_entry->delta_size &&
1550                     src->depth + 1 >= trg->depth) {
1551                         free(delta_buf);
1552                         return 0;
1553                 }
1554         }
1555
1556         /*
1557          * Handle memory allocation outside of the cache
1558          * accounting lock.  Compiler will optimize the strangeness
1559          * away when NO_PTHREADS is defined.
1560          */
1561         free(trg_entry->delta_data);
1562         cache_lock();
1563         if (trg_entry->delta_data) {
1564                 delta_cache_size -= trg_entry->delta_size;
1565                 trg_entry->delta_data = NULL;
1566         }
1567         if (delta_cacheable(src_size, trg_size, delta_size)) {
1568                 delta_cache_size += delta_size;
1569                 cache_unlock();
1570                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1571         } else {
1572                 cache_unlock();
1573                 free(delta_buf);
1574         }
1575
1576         trg_entry->delta = src_entry;
1577         trg_entry->delta_size = delta_size;
1578         trg->depth = src->depth + 1;
1579
1580         return 1;
1581 }
1582
1583 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1584 {
1585         struct object_entry *child = me->delta_child;
1586         unsigned int m = n;
1587         while (child) {
1588                 unsigned int c = check_delta_limit(child, n + 1);
1589                 if (m < c)
1590                         m = c;
1591                 child = child->delta_sibling;
1592         }
1593         return m;
1594 }
1595
1596 static unsigned long free_unpacked(struct unpacked *n)
1597 {
1598         unsigned long freed_mem = sizeof_delta_index(n->index);
1599         free_delta_index(n->index);
1600         n->index = NULL;
1601         if (n->data) {
1602                 freed_mem += n->entry->size;
1603                 free(n->data);
1604                 n->data = NULL;
1605         }
1606         n->entry = NULL;
1607         n->depth = 0;
1608         return freed_mem;
1609 }
1610
1611 static void find_deltas(struct object_entry **list, unsigned *list_size,
1612                         int window, int depth, unsigned *processed)
1613 {
1614         uint32_t i, idx = 0, count = 0;
1615         struct unpacked *array;
1616         unsigned long mem_usage = 0;
1617
1618         array = xcalloc(window, sizeof(struct unpacked));
1619
1620         for (;;) {
1621                 struct object_entry *entry;
1622                 struct unpacked *n = array + idx;
1623                 int j, max_depth, best_base = -1;
1624
1625                 progress_lock();
1626                 if (!*list_size) {
1627                         progress_unlock();
1628                         break;
1629                 }
1630                 entry = *list++;
1631                 (*list_size)--;
1632                 if (!entry->preferred_base) {
1633                         (*processed)++;
1634                         display_progress(progress_state, *processed);
1635                 }
1636                 progress_unlock();
1637
1638                 mem_usage -= free_unpacked(n);
1639                 n->entry = entry;
1640
1641                 while (window_memory_limit &&
1642                        mem_usage > window_memory_limit &&
1643                        count > 1) {
1644                         uint32_t tail = (idx + window - count) % window;
1645                         mem_usage -= free_unpacked(array + tail);
1646                         count--;
1647                 }
1648
1649                 /* We do not compute delta to *create* objects we are not
1650                  * going to pack.
1651                  */
1652                 if (entry->preferred_base)
1653                         goto next;
1654
1655                 /*
1656                  * If the current object is at pack edge, take the depth the
1657                  * objects that depend on the current object into account
1658                  * otherwise they would become too deep.
1659                  */
1660                 max_depth = depth;
1661                 if (entry->delta_child) {
1662                         max_depth -= check_delta_limit(entry, 0);
1663                         if (max_depth <= 0)
1664                                 goto next;
1665                 }
1666
1667                 j = window;
1668                 while (--j > 0) {
1669                         int ret;
1670                         uint32_t other_idx = idx + j;
1671                         struct unpacked *m;
1672                         if (other_idx >= window)
1673                                 other_idx -= window;
1674                         m = array + other_idx;
1675                         if (!m->entry)
1676                                 break;
1677                         ret = try_delta(n, m, max_depth, &mem_usage);
1678                         if (ret < 0)
1679                                 break;
1680                         else if (ret > 0)
1681                                 best_base = other_idx;
1682                 }
1683
1684                 /*
1685                  * If we decided to cache the delta data, then it is best
1686                  * to compress it right away.  First because we have to do
1687                  * it anyway, and doing it here while we're threaded will
1688                  * save a lot of time in the non threaded write phase,
1689                  * as well as allow for caching more deltas within
1690                  * the same cache size limit.
1691                  * ...
1692                  * But only if not writing to stdout, since in that case
1693                  * the network is most likely throttling writes anyway,
1694                  * and therefore it is best to go to the write phase ASAP
1695                  * instead, as we can afford spending more time compressing
1696                  * between writes at that moment.
1697                  */
1698                 if (entry->delta_data && !pack_to_stdout) {
1699                         entry->z_delta_size = do_compress(&entry->delta_data,
1700                                                           entry->delta_size);
1701                         cache_lock();
1702                         delta_cache_size -= entry->delta_size;
1703                         delta_cache_size += entry->z_delta_size;
1704                         cache_unlock();
1705                 }
1706
1707                 /* if we made n a delta, and if n is already at max
1708                  * depth, leaving it in the window is pointless.  we
1709                  * should evict it first.
1710                  */
1711                 if (entry->delta && max_depth <= n->depth)
1712                         continue;
1713
1714                 /*
1715                  * Move the best delta base up in the window, after the
1716                  * currently deltified object, to keep it longer.  It will
1717                  * be the first base object to be attempted next.
1718                  */
1719                 if (entry->delta) {
1720                         struct unpacked swap = array[best_base];
1721                         int dist = (window + idx - best_base) % window;
1722                         int dst = best_base;
1723                         while (dist--) {
1724                                 int src = (dst + 1) % window;
1725                                 array[dst] = array[src];
1726                                 dst = src;
1727                         }
1728                         array[dst] = swap;
1729                 }
1730
1731                 next:
1732                 idx++;
1733                 if (count + 1 < window)
1734                         count++;
1735                 if (idx >= window)
1736                         idx = 0;
1737         }
1738
1739         for (i = 0; i < window; ++i) {
1740                 free_delta_index(array[i].index);
1741                 free(array[i].data);
1742         }
1743         free(array);
1744 }
1745
1746 #ifndef NO_PTHREADS
1747
1748 static void try_to_free_from_threads(size_t size)
1749 {
1750         read_lock();
1751         release_pack_memory(size, -1);
1752         read_unlock();
1753 }
1754
1755 static try_to_free_t old_try_to_free_routine;
1756
1757 /*
1758  * The main thread waits on the condition that (at least) one of the workers
1759  * has stopped working (which is indicated in the .working member of
1760  * struct thread_params).
1761  * When a work thread has completed its work, it sets .working to 0 and
1762  * signals the main thread and waits on the condition that .data_ready
1763  * becomes 1.
1764  */
1765
1766 struct thread_params {
1767         pthread_t thread;
1768         struct object_entry **list;
1769         unsigned list_size;
1770         unsigned remaining;
1771         int window;
1772         int depth;
1773         int working;
1774         int data_ready;
1775         pthread_mutex_t mutex;
1776         pthread_cond_t cond;
1777         unsigned *processed;
1778 };
1779
1780 static pthread_cond_t progress_cond;
1781
1782 /*
1783  * Mutex and conditional variable can't be statically-initialized on Windows.
1784  */
1785 static void init_threaded_search(void)
1786 {
1787         init_recursive_mutex(&read_mutex);
1788         pthread_mutex_init(&cache_mutex, NULL);
1789         pthread_mutex_init(&progress_mutex, NULL);
1790         pthread_cond_init(&progress_cond, NULL);
1791         old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
1792 }
1793
1794 static void cleanup_threaded_search(void)
1795 {
1796         set_try_to_free_routine(old_try_to_free_routine);
1797         pthread_cond_destroy(&progress_cond);
1798         pthread_mutex_destroy(&read_mutex);
1799         pthread_mutex_destroy(&cache_mutex);
1800         pthread_mutex_destroy(&progress_mutex);
1801 }
1802
1803 static void *threaded_find_deltas(void *arg)
1804 {
1805         struct thread_params *me = arg;
1806
1807         while (me->remaining) {
1808                 find_deltas(me->list, &me->remaining,
1809                             me->window, me->depth, me->processed);
1810
1811                 progress_lock();
1812                 me->working = 0;
1813                 pthread_cond_signal(&progress_cond);
1814                 progress_unlock();
1815
1816                 /*
1817                  * We must not set ->data_ready before we wait on the
1818                  * condition because the main thread may have set it to 1
1819                  * before we get here. In order to be sure that new
1820                  * work is available if we see 1 in ->data_ready, it
1821                  * was initialized to 0 before this thread was spawned
1822                  * and we reset it to 0 right away.
1823                  */
1824                 pthread_mutex_lock(&me->mutex);
1825                 while (!me->data_ready)
1826                         pthread_cond_wait(&me->cond, &me->mutex);
1827                 me->data_ready = 0;
1828                 pthread_mutex_unlock(&me->mutex);
1829         }
1830         /* leave ->working 1 so that this doesn't get more work assigned */
1831         return NULL;
1832 }
1833
1834 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1835                            int window, int depth, unsigned *processed)
1836 {
1837         struct thread_params *p;
1838         int i, ret, active_threads = 0;
1839
1840         init_threaded_search();
1841
1842         if (!delta_search_threads)      /* --threads=0 means autodetect */
1843                 delta_search_threads = online_cpus();
1844         if (delta_search_threads <= 1) {
1845                 find_deltas(list, &list_size, window, depth, processed);
1846                 cleanup_threaded_search();
1847                 return;
1848         }
1849         if (progress > pack_to_stdout)
1850                 fprintf(stderr, "Delta compression using up to %d threads.\n",
1851                                 delta_search_threads);
1852         p = xcalloc(delta_search_threads, sizeof(*p));
1853
1854         /* Partition the work amongst work threads. */
1855         for (i = 0; i < delta_search_threads; i++) {
1856                 unsigned sub_size = list_size / (delta_search_threads - i);
1857
1858                 /* don't use too small segments or no deltas will be found */
1859                 if (sub_size < 2*window && i+1 < delta_search_threads)
1860                         sub_size = 0;
1861
1862                 p[i].window = window;
1863                 p[i].depth = depth;
1864                 p[i].processed = processed;
1865                 p[i].working = 1;
1866                 p[i].data_ready = 0;
1867
1868                 /* try to split chunks on "path" boundaries */
1869                 while (sub_size && sub_size < list_size &&
1870                        list[sub_size]->hash &&
1871                        list[sub_size]->hash == list[sub_size-1]->hash)
1872                         sub_size++;
1873
1874                 p[i].list = list;
1875                 p[i].list_size = sub_size;
1876                 p[i].remaining = sub_size;
1877
1878                 list += sub_size;
1879                 list_size -= sub_size;
1880         }
1881
1882         /* Start work threads. */
1883         for (i = 0; i < delta_search_threads; i++) {
1884                 if (!p[i].list_size)
1885                         continue;
1886                 pthread_mutex_init(&p[i].mutex, NULL);
1887                 pthread_cond_init(&p[i].cond, NULL);
1888                 ret = pthread_create(&p[i].thread, NULL,
1889                                      threaded_find_deltas, &p[i]);
1890                 if (ret)
1891                         die("unable to create thread: %s", strerror(ret));
1892                 active_threads++;
1893         }
1894
1895         /*
1896          * Now let's wait for work completion.  Each time a thread is done
1897          * with its work, we steal half of the remaining work from the
1898          * thread with the largest number of unprocessed objects and give
1899          * it to that newly idle thread.  This ensure good load balancing
1900          * until the remaining object list segments are simply too short
1901          * to be worth splitting anymore.
1902          */
1903         while (active_threads) {
1904                 struct thread_params *target = NULL;
1905                 struct thread_params *victim = NULL;
1906                 unsigned sub_size = 0;
1907
1908                 progress_lock();
1909                 for (;;) {
1910                         for (i = 0; !target && i < delta_search_threads; i++)
1911                                 if (!p[i].working)
1912                                         target = &p[i];
1913                         if (target)
1914                                 break;
1915                         pthread_cond_wait(&progress_cond, &progress_mutex);
1916                 }
1917
1918                 for (i = 0; i < delta_search_threads; i++)
1919                         if (p[i].remaining > 2*window &&
1920                             (!victim || victim->remaining < p[i].remaining))
1921                                 victim = &p[i];
1922                 if (victim) {
1923                         sub_size = victim->remaining / 2;
1924                         list = victim->list + victim->list_size - sub_size;
1925                         while (sub_size && list[0]->hash &&
1926                                list[0]->hash == list[-1]->hash) {
1927                                 list++;
1928                                 sub_size--;
1929                         }
1930                         if (!sub_size) {
1931                                 /*
1932                                  * It is possible for some "paths" to have
1933                                  * so many objects that no hash boundary
1934                                  * might be found.  Let's just steal the
1935                                  * exact half in that case.
1936                                  */
1937                                 sub_size = victim->remaining / 2;
1938                                 list -= sub_size;
1939                         }
1940                         target->list = list;
1941                         victim->list_size -= sub_size;
1942                         victim->remaining -= sub_size;
1943                 }
1944                 target->list_size = sub_size;
1945                 target->remaining = sub_size;
1946                 target->working = 1;
1947                 progress_unlock();
1948
1949                 pthread_mutex_lock(&target->mutex);
1950                 target->data_ready = 1;
1951                 pthread_cond_signal(&target->cond);
1952                 pthread_mutex_unlock(&target->mutex);
1953
1954                 if (!sub_size) {
1955                         pthread_join(target->thread, NULL);
1956                         pthread_cond_destroy(&target->cond);
1957                         pthread_mutex_destroy(&target->mutex);
1958                         active_threads--;
1959                 }
1960         }
1961         cleanup_threaded_search();
1962         free(p);
1963 }
1964
1965 #else
1966 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
1967 #endif
1968
1969 static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1970 {
1971         unsigned char peeled[20];
1972
1973         if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
1974             !peel_ref(path, peeled)        && /* peelable? */
1975             !is_null_sha1(peeled)          && /* annotated tag? */
1976             locate_object_entry(peeled))      /* object packed? */
1977                 add_object_entry(sha1, OBJ_TAG, NULL, 0);
1978         return 0;
1979 }
1980
1981 static void prepare_pack(int window, int depth)
1982 {
1983         struct object_entry **delta_list;
1984         uint32_t i, nr_deltas;
1985         unsigned n;
1986
1987         get_object_details();
1988
1989         /*
1990          * If we're locally repacking then we need to be doubly careful
1991          * from now on in order to make sure no stealth corruption gets
1992          * propagated to the new pack.  Clients receiving streamed packs
1993          * should validate everything they get anyway so no need to incur
1994          * the additional cost here in that case.
1995          */
1996         if (!pack_to_stdout)
1997                 do_check_packed_object_crc = 1;
1998
1999         if (!nr_objects || !window || !depth)
2000                 return;
2001
2002         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
2003         nr_deltas = n = 0;
2004
2005         for (i = 0; i < nr_objects; i++) {
2006                 struct object_entry *entry = objects + i;
2007
2008                 if (entry->delta)
2009                         /* This happens if we decided to reuse existing
2010                          * delta from a pack.  "reuse_delta &&" is implied.
2011                          */
2012                         continue;
2013
2014                 if (entry->size < 50)
2015                         continue;
2016
2017                 if (entry->no_try_delta)
2018                         continue;
2019
2020                 if (!entry->preferred_base) {
2021                         nr_deltas++;
2022                         if (entry->type < 0)
2023                                 die("unable to get type of object %s",
2024                                     sha1_to_hex(entry->idx.sha1));
2025                 } else {
2026                         if (entry->type < 0) {
2027                                 /*
2028                                  * This object is not found, but we
2029                                  * don't have to include it anyway.
2030                                  */
2031                                 continue;
2032                         }
2033                 }
2034
2035                 delta_list[n++] = entry;
2036         }
2037
2038         if (nr_deltas && n > 1) {
2039                 unsigned nr_done = 0;
2040                 if (progress)
2041                         progress_state = start_progress("Compressing objects",
2042                                                         nr_deltas);
2043                 qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
2044                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2045                 stop_progress(&progress_state);
2046                 if (nr_done != nr_deltas)
2047                         die("inconsistency with delta count");
2048         }
2049         free(delta_list);
2050 }
2051
2052 static int git_pack_config(const char *k, const char *v, void *cb)
2053 {
2054         if (!strcmp(k, "pack.window")) {
2055                 window = git_config_int(k, v);
2056                 return 0;
2057         }
2058         if (!strcmp(k, "pack.windowmemory")) {
2059                 window_memory_limit = git_config_ulong(k, v);
2060                 return 0;
2061         }
2062         if (!strcmp(k, "pack.depth")) {
2063                 depth = git_config_int(k, v);
2064                 return 0;
2065         }
2066         if (!strcmp(k, "pack.compression")) {
2067                 int level = git_config_int(k, v);
2068                 if (level == -1)
2069                         level = Z_DEFAULT_COMPRESSION;
2070                 else if (level < 0 || level > Z_BEST_COMPRESSION)
2071                         die("bad pack compression level %d", level);
2072                 pack_compression_level = level;
2073                 pack_compression_seen = 1;
2074                 return 0;
2075         }
2076         if (!strcmp(k, "pack.deltacachesize")) {
2077                 max_delta_cache_size = git_config_int(k, v);
2078                 return 0;
2079         }
2080         if (!strcmp(k, "pack.deltacachelimit")) {
2081                 cache_max_small_delta_size = git_config_int(k, v);
2082                 return 0;
2083         }
2084         if (!strcmp(k, "pack.threads")) {
2085                 delta_search_threads = git_config_int(k, v);
2086                 if (delta_search_threads < 0)
2087                         die("invalid number of threads specified (%d)",
2088                             delta_search_threads);
2089 #ifdef NO_PTHREADS
2090                 if (delta_search_threads != 1)
2091                         warning("no threads support, ignoring %s", k);
2092 #endif
2093                 return 0;
2094         }
2095         if (!strcmp(k, "pack.indexversion")) {
2096                 pack_idx_opts.version = git_config_int(k, v);
2097                 if (pack_idx_opts.version > 2)
2098                         die("bad pack.indexversion=%"PRIu32,
2099                             pack_idx_opts.version);
2100                 return 0;
2101         }
2102         return git_default_config(k, v, cb);
2103 }
2104
2105 static void read_object_list_from_stdin(void)
2106 {
2107         char line[40 + 1 + PATH_MAX + 2];
2108         unsigned char sha1[20];
2109
2110         for (;;) {
2111                 if (!fgets(line, sizeof(line), stdin)) {
2112                         if (feof(stdin))
2113                                 break;
2114                         if (!ferror(stdin))
2115                                 die("fgets returned NULL, not EOF, not error!");
2116                         if (errno != EINTR)
2117                                 die_errno("fgets");
2118                         clearerr(stdin);
2119                         continue;
2120                 }
2121                 if (line[0] == '-') {
2122                         if (get_sha1_hex(line+1, sha1))
2123                                 die("expected edge sha1, got garbage:\n %s",
2124                                     line);
2125                         add_preferred_base(sha1);
2126                         continue;
2127                 }
2128                 if (get_sha1_hex(line, sha1))
2129                         die("expected sha1, got garbage:\n %s", line);
2130
2131                 add_preferred_base_object(line+41);
2132                 add_object_entry(sha1, 0, line+41, 0);
2133         }
2134 }
2135
2136 #define OBJECT_ADDED (1u<<20)
2137
2138 static void show_commit(struct commit *commit, void *data)
2139 {
2140         add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
2141         commit->object.flags |= OBJECT_ADDED;
2142 }
2143
2144 static void show_object(struct object *obj,
2145                         const struct name_path *path, const char *last,
2146                         void *data)
2147 {
2148         char *name = path_name(path, last);
2149
2150         add_preferred_base_object(name);
2151         add_object_entry(obj->sha1, obj->type, name, 0);
2152         obj->flags |= OBJECT_ADDED;
2153
2154         /*
2155          * We will have generated the hash from the name,
2156          * but not saved a pointer to it - we can free it
2157          */
2158         free((char *)name);
2159 }
2160
2161 static void show_edge(struct commit *commit)
2162 {
2163         add_preferred_base(commit->object.sha1);
2164 }
2165
2166 struct in_pack_object {
2167         off_t offset;
2168         struct object *object;
2169 };
2170
2171 struct in_pack {
2172         int alloc;
2173         int nr;
2174         struct in_pack_object *array;
2175 };
2176
2177 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2178 {
2179         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
2180         in_pack->array[in_pack->nr].object = object;
2181         in_pack->nr++;
2182 }
2183
2184 /*
2185  * Compare the objects in the offset order, in order to emulate the
2186  * "git rev-list --objects" output that produced the pack originally.
2187  */
2188 static int ofscmp(const void *a_, const void *b_)
2189 {
2190         struct in_pack_object *a = (struct in_pack_object *)a_;
2191         struct in_pack_object *b = (struct in_pack_object *)b_;
2192
2193         if (a->offset < b->offset)
2194                 return -1;
2195         else if (a->offset > b->offset)
2196                 return 1;
2197         else
2198                 return hashcmp(a->object->sha1, b->object->sha1);
2199 }
2200
2201 static void add_objects_in_unpacked_packs(struct rev_info *revs)
2202 {
2203         struct packed_git *p;
2204         struct in_pack in_pack;
2205         uint32_t i;
2206
2207         memset(&in_pack, 0, sizeof(in_pack));
2208
2209         for (p = packed_git; p; p = p->next) {
2210                 const unsigned char *sha1;
2211                 struct object *o;
2212
2213                 if (!p->pack_local || p->pack_keep)
2214                         continue;
2215                 if (open_pack_index(p))
2216                         die("cannot open pack index");
2217
2218                 ALLOC_GROW(in_pack.array,
2219                            in_pack.nr + p->num_objects,
2220                            in_pack.alloc);
2221
2222                 for (i = 0; i < p->num_objects; i++) {
2223                         sha1 = nth_packed_object_sha1(p, i);
2224                         o = lookup_unknown_object(sha1);
2225                         if (!(o->flags & OBJECT_ADDED))
2226                                 mark_in_pack_object(o, p, &in_pack);
2227                         o->flags |= OBJECT_ADDED;
2228                 }
2229         }
2230
2231         if (in_pack.nr) {
2232                 qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
2233                       ofscmp);
2234                 for (i = 0; i < in_pack.nr; i++) {
2235                         struct object *o = in_pack.array[i].object;
2236                         add_object_entry(o->sha1, o->type, "", 0);
2237                 }
2238         }
2239         free(in_pack.array);
2240 }
2241
2242 static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
2243 {
2244         static struct packed_git *last_found = (void *)1;
2245         struct packed_git *p;
2246
2247         p = (last_found != (void *)1) ? last_found : packed_git;
2248
2249         while (p) {
2250                 if ((!p->pack_local || p->pack_keep) &&
2251                         find_pack_entry_one(sha1, p)) {
2252                         last_found = p;
2253                         return 1;
2254                 }
2255                 if (p == last_found)
2256                         p = packed_git;
2257                 else
2258                         p = p->next;
2259                 if (p == last_found)
2260                         p = p->next;
2261         }
2262         return 0;
2263 }
2264
2265 static void loosen_unused_packed_objects(struct rev_info *revs)
2266 {
2267         struct packed_git *p;
2268         uint32_t i;
2269         const unsigned char *sha1;
2270
2271         for (p = packed_git; p; p = p->next) {
2272                 if (!p->pack_local || p->pack_keep)
2273                         continue;
2274
2275                 if (unpack_unreachable_expiration &&
2276                     p->mtime < unpack_unreachable_expiration)
2277                         continue;
2278
2279                 if (open_pack_index(p))
2280                         die("cannot open pack index");
2281
2282                 for (i = 0; i < p->num_objects; i++) {
2283                         sha1 = nth_packed_object_sha1(p, i);
2284                         if (!locate_object_entry(sha1) &&
2285                                 !has_sha1_pack_kept_or_nonlocal(sha1))
2286                                 if (force_object_loose(sha1, p->mtime))
2287                                         die("unable to force loose object");
2288                 }
2289         }
2290 }
2291
2292 static void get_object_list(int ac, const char **av)
2293 {
2294         struct rev_info revs;
2295         char line[1000];
2296         int flags = 0;
2297
2298         init_revisions(&revs, NULL);
2299         save_commit_buffer = 0;
2300         setup_revisions(ac, av, &revs, NULL);
2301
2302         while (fgets(line, sizeof(line), stdin) != NULL) {
2303                 int len = strlen(line);
2304                 if (len && line[len - 1] == '\n')
2305                         line[--len] = 0;
2306                 if (!len)
2307                         break;
2308                 if (*line == '-') {
2309                         if (!strcmp(line, "--not")) {
2310                                 flags ^= UNINTERESTING;
2311                                 continue;
2312                         }
2313                         die("not a rev '%s'", line);
2314                 }
2315                 if (handle_revision_arg(line, &revs, flags, 1))
2316                         die("bad revision '%s'", line);
2317         }
2318
2319         if (prepare_revision_walk(&revs))
2320                 die("revision walk setup failed");
2321         mark_edges_uninteresting(revs.commits, &revs, show_edge);
2322         traverse_commit_list(&revs, show_commit, show_object, NULL);
2323
2324         if (keep_unreachable)
2325                 add_objects_in_unpacked_packs(&revs);
2326         if (unpack_unreachable)
2327                 loosen_unused_packed_objects(&revs);
2328 }
2329
2330 static int option_parse_index_version(const struct option *opt,
2331                                       const char *arg, int unset)
2332 {
2333         char *c;
2334         const char *val = arg;
2335         pack_idx_opts.version = strtoul(val, &c, 10);
2336         if (pack_idx_opts.version > 2)
2337                 die(_("unsupported index version %s"), val);
2338         if (*c == ',' && c[1])
2339                 pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2340         if (*c || pack_idx_opts.off32_limit & 0x80000000)
2341                 die(_("bad index version '%s'"), val);
2342         return 0;
2343 }
2344
2345 static int option_parse_unpack_unreachable(const struct option *opt,
2346                                            const char *arg, int unset)
2347 {
2348         if (unset) {
2349                 unpack_unreachable = 0;
2350                 unpack_unreachable_expiration = 0;
2351         }
2352         else {
2353                 unpack_unreachable = 1;
2354                 if (arg)
2355                         unpack_unreachable_expiration = approxidate(arg);
2356         }
2357         return 0;
2358 }
2359
2360 static int option_parse_ulong(const struct option *opt,
2361                               const char *arg, int unset)
2362 {
2363         if (unset)
2364                 die(_("option %s does not accept negative form"),
2365                     opt->long_name);
2366
2367         if (!git_parse_ulong(arg, opt->value))
2368                 die(_("unable to parse value '%s' for option %s"),
2369                     arg, opt->long_name);
2370         return 0;
2371 }
2372
2373 #define OPT_ULONG(s, l, v, h) \
2374         { OPTION_CALLBACK, (s), (l), (v), "n", (h),     \
2375           PARSE_OPT_NONEG, option_parse_ulong }
2376
2377 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2378 {
2379         int use_internal_rev_list = 0;
2380         int thin = 0;
2381         int all_progress_implied = 0;
2382         const char *rp_av[6];
2383         int rp_ac = 0;
2384         int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
2385         struct option pack_objects_options[] = {
2386                 OPT_SET_INT('q', "quiet", &progress,
2387                             "do not show progress meter", 0),
2388                 OPT_SET_INT(0, "progress", &progress,
2389                             "show progress meter", 1),
2390                 OPT_SET_INT(0, "all-progress", &progress,
2391                             "show progress meter during object writing phase", 2),
2392                 OPT_BOOL(0, "all-progress-implied",
2393                          &all_progress_implied,
2394                          "similar to --all-progress when progress meter is shown"),
2395                 { OPTION_CALLBACK, 0, "index-version", NULL, "version[,offset]",
2396                   "write the pack index file in the specified idx format version",
2397                   0, option_parse_index_version },
2398                 OPT_ULONG(0, "max-pack-size", &pack_size_limit,
2399                           "maximum size of each output pack file"),
2400                 OPT_BOOL(0, "local", &local,
2401                          "ignore borrowed objects from alternate object store"),
2402                 OPT_BOOL(0, "incremental", &incremental,
2403                          "ignore packed objects"),
2404                 OPT_INTEGER(0, "window", &window,
2405                             "limit pack window by objects"),
2406                 OPT_ULONG(0, "window-memory", &window_memory_limit,
2407                           "limit pack window by memory in addition to object limit"),
2408                 OPT_INTEGER(0, "depth", &depth,
2409                             "maximum length of delta chain allowed in the resulting pack"),
2410                 OPT_BOOL(0, "reuse-delta", &reuse_delta,
2411                          "reuse existing deltas"),
2412                 OPT_BOOL(0, "reuse-object", &reuse_object,
2413                          "reuse existing objects"),
2414                 OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
2415                          "use OFS_DELTA objects"),
2416                 OPT_INTEGER(0, "threads", &delta_search_threads,
2417                             "use threads when searching for best delta matches"),
2418                 OPT_BOOL(0, "non-empty", &non_empty,
2419                          "do not create an empty pack output"),
2420                 OPT_BOOL(0, "revs", &use_internal_rev_list,
2421                          "read revision arguments from standard input"),
2422                 { OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
2423                   "limit the objects to those that are not yet packed",
2424                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2425                 { OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
2426                   "include objects reachable from any reference",
2427                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2428                 { OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
2429                   "include objects referred by reflog entries",
2430                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2431                 OPT_BOOL(0, "stdout", &pack_to_stdout,
2432                          "output pack to stdout"),
2433                 OPT_BOOL(0, "include-tag", &include_tag,
2434                          "include tag objects that refer to objects to be packed"),
2435                 OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
2436                          "keep unreachable objects"),
2437                 { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, "time",
2438                   "unpack unreachable objects newer than <time>",
2439                   PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
2440                 OPT_BOOL(0, "thin", &thin,
2441                          "create thin packs"),
2442                 OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
2443                          "ignore packs that have companion .keep file"),
2444                 OPT_INTEGER(0, "compression", &pack_compression_level,
2445                             "pack compression level"),
2446                 OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
2447                             "do not hide commits by grafts", 0),
2448                 OPT_END(),
2449         };
2450
2451         read_replace_refs = 0;
2452
2453         reset_pack_idx_option(&pack_idx_opts);
2454         git_config(git_pack_config, NULL);
2455         if (!pack_compression_seen && core_compression_seen)
2456                 pack_compression_level = core_compression_level;
2457
2458         progress = isatty(2);
2459         argc = parse_options(argc, argv, prefix, pack_objects_options,
2460                              pack_usage, 0);
2461
2462         if (argc) {
2463                 base_name = argv[0];
2464                 argc--;
2465         }
2466         if (pack_to_stdout != !base_name || argc)
2467                 usage_with_options(pack_usage, pack_objects_options);
2468
2469         rp_av[rp_ac++] = "pack-objects";
2470         if (thin) {
2471                 use_internal_rev_list = 1;
2472                 rp_av[rp_ac++] = "--objects-edge";
2473         } else
2474                 rp_av[rp_ac++] = "--objects";
2475
2476         if (rev_list_all) {
2477                 use_internal_rev_list = 1;
2478                 rp_av[rp_ac++] = "--all";
2479         }
2480         if (rev_list_reflog) {
2481                 use_internal_rev_list = 1;
2482                 rp_av[rp_ac++] = "--reflog";
2483         }
2484         if (rev_list_unpacked) {
2485                 use_internal_rev_list = 1;
2486                 rp_av[rp_ac++] = "--unpacked";
2487         }
2488
2489         if (!reuse_object)
2490                 reuse_delta = 0;
2491         if (pack_compression_level == -1)
2492                 pack_compression_level = Z_DEFAULT_COMPRESSION;
2493         else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
2494                 die("bad pack compression level %d", pack_compression_level);
2495 #ifdef NO_PTHREADS
2496         if (delta_search_threads != 1)
2497                 warning("no threads support, ignoring --threads");
2498 #endif
2499         if (!pack_to_stdout && !pack_size_limit)
2500                 pack_size_limit = pack_size_limit_cfg;
2501         if (pack_to_stdout && pack_size_limit)
2502                 die("--max-pack-size cannot be used to build a pack for transfer.");
2503         if (pack_size_limit && pack_size_limit < 1024*1024) {
2504                 warning("minimum pack size limit is 1 MiB");
2505                 pack_size_limit = 1024*1024;
2506         }
2507
2508         if (!pack_to_stdout && thin)
2509                 die("--thin cannot be used to build an indexable pack.");
2510
2511         if (keep_unreachable && unpack_unreachable)
2512                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
2513
2514         if (progress && all_progress_implied)
2515                 progress = 2;
2516
2517         prepare_packed_git();
2518
2519         if (progress)
2520                 progress_state = start_progress("Counting objects", 0);
2521         if (!use_internal_rev_list)
2522                 read_object_list_from_stdin();
2523         else {
2524                 rp_av[rp_ac] = NULL;
2525                 get_object_list(rp_ac, rp_av);
2526         }
2527         cleanup_preferred_base();
2528         if (include_tag && nr_result)
2529                 for_each_ref(add_ref_tag, NULL);
2530         stop_progress(&progress_state);
2531
2532         if (non_empty && !nr_result)
2533                 return 0;
2534         if (nr_result)
2535                 prepare_pack(window, depth);
2536         write_pack_file();
2537         if (progress)
2538                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
2539                         " reused %"PRIu32" (delta %"PRIu32")\n",
2540                         written, written_delta, reused, reused_delta);
2541         return 0;
2542 }