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
  20 #ifdef THREADED_DELTA_SEARCH
  21 #include "thread-utils.h"
  22 #include <pthread.h>
  23 #endif
  24
  25 static const char pack_usage[] = "\
  26 git pack-objects [{ -q | --progress | --all-progress }] \n\
  27         [--max-pack-size=N] [--local] [--incremental] \n\
  28         [--window=N] [--window-memory=N] [--depth=N] \n\
  29         [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
  30         [--threads=N] [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
  31         [--stdout | base-name] [--include-tag] \n\
  32         [--keep-unreachable | --unpack-unreachable] \n\
  33         [<ref-list | <object-list]";
  34
  35 struct object_entry {
  36         struct pack_idx_entry idx;
  37         unsigned long size;     /* uncompressed size */
  38         struct packed_git *in_pack;     /* already in pack */
  39         off_t in_pack_offset;
  40         struct object_entry *delta;     /* delta base object */
  41         struct object_entry *delta_child; /* deltified objects who bases me */
  42         struct object_entry *delta_sibling; /* other deltified objects who
  43                                              * uses the same base as me
  44                                              */
  45         void *delta_data;       /* cached delta (uncompressed) */
  46         unsigned long delta_size;       /* delta data size (uncompressed) */
  47         unsigned long z_delta_size;     /* delta data size (compressed) */
  48         unsigned int hash;      /* name hint hash */
  49         enum object_type type;
  50         enum object_type in_pack_type;  /* could be delta */
  51         unsigned char in_pack_header_size;
  52         unsigned char preferred_base; /* we do not pack this, but is available
  53                                        * to be used as the base object to delta
  54                                        * objects against.
  55                                        */
  56         unsigned char no_try_delta;
  57 };
  58
  59 /*
  60  * Objects we are going to pack are collected in objects array (dynamically
  61  * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  62  * in the order we see -- typically rev-list --objects order that gives us
  63  * nice "minimum seek" order.
  64  */
  65 static struct object_entry *objects;
  66 static struct pack_idx_entry **written_list;
  67 static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  68
  69 static int non_empty;
  70 static int reuse_delta = 1, reuse_object = 1;
  71 static int keep_unreachable, unpack_unreachable, include_tag;
  72 static int local;
  73 static int incremental;
  74 static int allow_ofs_delta;
  75 static const char *base_name;
  76 static int progress = 1;
  77 static int window = 10;
  78 static uint32_t pack_size_limit, pack_size_limit_cfg;
  79 static int depth = 50;
  80 static int delta_search_threads = 1;
  81 static int pack_to_stdout;
  82 static int num_preferred_base;
  83 static struct progress *progress_state;
  84 static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  85 static int pack_compression_seen;
  86
  87 static unsigned long delta_cache_size = 0;
  88 static unsigned long max_delta_cache_size = 0;
  89 static unsigned long cache_max_small_delta_size = 1000;
  90
  91 static unsigned long window_memory_limit = 0;
  92
  93 /*
  94  * The object names in objects array are hashed with this hashtable,
  95  * to help looking up the entry by object name.
  96  * This hashtable is built after all the objects are seen.
  97  */
  98 static int *object_ix;
  99 static int object_ix_hashsz;
 100
 101 /*
 102  * stats
 103  */
 104 static uint32_t written, written_delta;
 105 static uint32_t reused, reused_delta;
 106
 107
 108 static void *get_delta(struct object_entry *entry)
 109 {
 110         unsigned long size, base_size, delta_size;
 111         void *buf, *base_buf, *delta_buf;
 112         enum object_type type;
 113
 114         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 115         if (!buf)
 116                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 117         base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
 118         if (!base_buf)
 119                 die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 120         delta_buf = diff_delta(base_buf, base_size,
 121                                buf, size, &delta_size, 0);
 122         if (!delta_buf || delta_size != entry->delta_size)
 123                 die("delta size changed");
 124         free(buf);
 125         free(base_buf);
 126         return delta_buf;
 127 }
 128
 129 static unsigned long do_compress(void **pptr, unsigned long size)
 130 {
 131         z_stream stream;
 132         void *in, *out;
 133         unsigned long maxsize;
 134
 135         memset(&stream, 0, sizeof(stream));
 136         deflateInit(&stream, pack_compression_level);
 137         maxsize = deflateBound(&stream, size);
 138
 139         in = *pptr;
 140         out = xmalloc(maxsize);
 141         *pptr = out;
 142
 143         stream.next_in = in;
 144         stream.avail_in = size;
 145         stream.next_out = out;
 146         stream.avail_out = maxsize;
 147         while (deflate(&stream, Z_FINISH) == Z_OK)
 148                 ; /* nothing */
 149         deflateEnd(&stream);
 150
 151         free(in);
 152         return stream.total_out;
 153 }
 154
 155 /*
 156  * The per-object header is a pretty dense thing, which is
 157  *  - first byte: low four bits are "size", then three bits of "type",
 158  *    and the high bit is "size continues".
 159  *  - each byte afterwards: low seven bits are size continuation,
 160  *    with the high bit being "size continues"
 161  */
 162 static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 163 {
 164         int n = 1;
 165         unsigned char c;
 166
 167         if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 168                 die("bad type %d", type);
 169
 170         c = (type << 4) | (size & 15);
 171         size >>= 4;
 172         while (size) {
 173                 *hdr++ = c | 0x80;
 174                 c = size & 0x7f;
 175                 size >>= 7;
 176                 n++;
 177         }
 178         *hdr = c;
 179         return n;
 180 }
 181
 182 /*
 183  * we are going to reuse the existing object data as is.  make
 184  * sure it is not corrupt.
 185  */
 186 static int check_pack_inflate(struct packed_git *p,
 187                 struct pack_window **w_curs,
 188                 off_t offset,
 189                 off_t len,
 190                 unsigned long expect)
 191 {
 192         z_stream stream;
 193         unsigned char fakebuf[4096], *in;
 194         int st;
 195
 196         memset(&stream, 0, sizeof(stream));
 197         inflateInit(&stream);
 198         do {
 199                 in = use_pack(p, w_curs, offset, &stream.avail_in);
 200                 stream.next_in = in;
 201                 stream.next_out = fakebuf;
 202                 stream.avail_out = sizeof(fakebuf);
 203                 st = inflate(&stream, Z_FINISH);
 204                 offset += stream.next_in - in;
 205         } while (st == Z_OK || st == Z_BUF_ERROR);
 206         inflateEnd(&stream);
 207         return (st == Z_STREAM_END &&
 208                 stream.total_out == expect &&
 209                 stream.total_in == len) ? 0 : -1;
 210 }
 211
 212 static void copy_pack_data(struct sha1file *f,
 213                 struct packed_git *p,
 214                 struct pack_window **w_curs,
 215                 off_t offset,
 216                 off_t len)
 217 {
 218         unsigned char *in;
 219         unsigned int avail;
 220
 221         while (len) {
 222                 in = use_pack(p, w_curs, offset, &avail);
 223                 if (avail > len)
 224                         avail = (unsigned int)len;
 225                 sha1write(f, in, avail);
 226                 offset += avail;
 227                 len -= avail;
 228         }
 229 }
 230
 231 static unsigned long write_object(struct sha1file *f,
 232                                   struct object_entry *entry,
 233                                   off_t write_offset)
 234 {
 235         unsigned long size, limit, datalen;
 236         void *buf;
 237         unsigned char header[10], dheader[10];
 238         unsigned hdrlen;
 239         enum object_type type;
 240         int usable_delta, to_reuse;
 241
 242         if (!pack_to_stdout)
 243                 crc32_begin(f);
 244
 245         type = entry->type;
 246
 247         /* write limit if limited packsize and not first object */
 248         limit = pack_size_limit && nr_written ?
 249                         pack_size_limit - write_offset : 0;
 250
 251         if (!entry->delta)
 252                 usable_delta = 0;       /* no delta */
 253         else if (!pack_size_limit)
 254                usable_delta = 1;        /* unlimited packfile */
 255         else if (entry->delta->idx.offset == (off_t)-1)
 256                 usable_delta = 0;       /* base was written to another pack */
 257         else if (entry->delta->idx.offset)
 258                 usable_delta = 1;       /* base already exists in this pack */
 259         else
 260                 usable_delta = 0;       /* base could end up in another pack */
 261
 262         if (!reuse_object)
 263                 to_reuse = 0;   /* explicit */
 264         else if (!entry->in_pack)
 265                 to_reuse = 0;   /* can't reuse what we don't have */
 266         else if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA)
 267                                 /* check_object() decided it for us ... */
 268                 to_reuse = usable_delta;
 269                                 /* ... but pack split may override that */
 270         else if (type != entry->in_pack_type)
 271                 to_reuse = 0;   /* pack has delta which is unusable */
 272         else if (entry->delta)
 273                 to_reuse = 0;   /* we want to pack afresh */
 274         else
 275                 to_reuse = 1;   /* we have it in-pack undeltified,
 276                                  * and we do not need to deltify it.
 277                                  */
 278
 279         if (!to_reuse) {
 280                 if (!usable_delta) {
 281                         buf = read_sha1_file(entry->idx.sha1, &type, &size);
 282                         if (!buf)
 283                                 die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 284                         /*
 285                          * make sure no cached delta data remains from a
 286                          * previous attempt before a pack split occured.
 287                          */
 288                         free(entry->delta_data);
 289                         entry->delta_data = NULL;
 290                         entry->z_delta_size = 0;
 291                 } else if (entry->delta_data) {
 292                         size = entry->delta_size;
 293                         buf = entry->delta_data;
 294                         entry->delta_data = NULL;
 295                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 296                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 297                 } else {
 298                         buf = get_delta(entry);
 299                         size = entry->delta_size;
 300                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 301                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 302                 }
 303
 304                 if (entry->z_delta_size)
 305                         datalen = entry->z_delta_size;
 306                 else
 307                         datalen = do_compress(&buf, size);
 308
 309                 /*
 310                  * The object header is a byte of 'type' followed by zero or
 311                  * more bytes of length.
 312                  */
 313                 hdrlen = encode_header(type, size, header);
 314
 315                 if (type == OBJ_OFS_DELTA) {
 316                         /*
 317                          * Deltas with relative base contain an additional
 318                          * encoding of the relative offset for the delta
 319                          * base from this object's position in the pack.
 320                          */
 321                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 322                         unsigned pos = sizeof(dheader) - 1;
 323                         dheader[pos] = ofs & 127;
 324                         while (ofs >>= 7)
 325                                 dheader[--pos] = 128 | (--ofs & 127);
 326                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 327                                 free(buf);
 328                                 return 0;
 329                         }
 330                         sha1write(f, header, hdrlen);
 331                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 332                         hdrlen += sizeof(dheader) - pos;
 333                 } else if (type == OBJ_REF_DELTA) {
 334                         /*
 335                          * Deltas with a base reference contain
 336                          * an additional 20 bytes for the base sha1.
 337                          */
 338                         if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 339                                 free(buf);
 340                                 return 0;
 341                         }
 342                         sha1write(f, header, hdrlen);
 343                         sha1write(f, entry->delta->idx.sha1, 20);
 344                         hdrlen += 20;
 345                 } else {
 346                         if (limit && hdrlen + datalen + 20 >= limit) {
 347                                 free(buf);
 348                                 return 0;
 349                         }
 350                         sha1write(f, header, hdrlen);
 351                 }
 352                 sha1write(f, buf, datalen);
 353                 free(buf);
 354         }
 355         else {
 356                 struct packed_git *p = entry->in_pack;
 357                 struct pack_window *w_curs = NULL;
 358                 struct revindex_entry *revidx;
 359                 off_t offset;
 360
 361                 if (entry->delta) {
 362                         type = (allow_ofs_delta && entry->delta->idx.offset) ?
 363                                 OBJ_OFS_DELTA : OBJ_REF_DELTA;
 364                         reused_delta++;
 365                 }
 366                 hdrlen = encode_header(type, entry->size, header);
 367                 offset = entry->in_pack_offset;
 368                 revidx = find_pack_revindex(p, offset);
 369                 datalen = revidx[1].offset - offset;
 370                 if (!pack_to_stdout && p->index_version > 1 &&
 371                     check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
 372                         die("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 373                 offset += entry->in_pack_header_size;
 374                 datalen -= entry->in_pack_header_size;
 375                 if (type == OBJ_OFS_DELTA) {
 376                         off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 377                         unsigned pos = sizeof(dheader) - 1;
 378                         dheader[pos] = ofs & 127;
 379                         while (ofs >>= 7)
 380                                 dheader[--pos] = 128 | (--ofs & 127);
 381                         if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit)
 382                                 return 0;
 383                         sha1write(f, header, hdrlen);
 384                         sha1write(f, dheader + pos, sizeof(dheader) - pos);
 385                         hdrlen += sizeof(dheader) - pos;
 386                 } else if (type == OBJ_REF_DELTA) {
 387                         if (limit && hdrlen + 20 + datalen + 20 >= limit)
 388                                 return 0;
 389                         sha1write(f, header, hdrlen);
 390                         sha1write(f, entry->delta->idx.sha1, 20);
 391                         hdrlen += 20;
 392                 } else {
 393                         if (limit && hdrlen + datalen + 20 >= limit)
 394                                 return 0;
 395                         sha1write(f, header, hdrlen);
 396                 }
 397
 398                 if (!pack_to_stdout && p->index_version == 1 &&
 399                     check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
 400                         die("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 401                 copy_pack_data(f, p, &w_curs, offset, datalen);
 402                 unuse_pack(&w_curs);
 403                 reused++;
 404         }
 405         if (usable_delta)
 406                 written_delta++;
 407         written++;
 408         if (!pack_to_stdout)
 409                 entry->idx.crc32 = crc32_end(f);
 410         return hdrlen + datalen;
 411 }
 412
 413 static int write_one(struct sha1file *f,
 414                                struct object_entry *e,
 415                                off_t *offset)
 416 {
 417         unsigned long size;
 418
 419         /* offset is non zero if object is written already. */
 420         if (e->idx.offset || e->preferred_base)
 421                 return 1;
 422
 423         /* if we are deltified, write out base object first. */
 424         if (e->delta && !write_one(f, e->delta, offset))
 425                 return 0;
 426
 427         e->idx.offset = *offset;
 428         size = write_object(f, e, *offset);
 429         if (!size) {
 430                 e->idx.offset = 0;
 431                 return 0;
 432         }
 433         written_list[nr_written++] = &e->idx;
 434
 435         /* make sure off_t is sufficiently large not to wrap */
 436         if (*offset > *offset + size)
 437                 die("pack too large for current definition of off_t");
 438         *offset += size;
 439         return 1;
 440 }
 441
 442 /* forward declaration for write_pack_file */
 443 static int adjust_perm(const char *path, mode_t mode);
 444
 445 static void write_pack_file(void)
 446 {
 447         uint32_t i = 0, j;
 448         struct sha1file *f;
 449         off_t offset;
 450         struct pack_header hdr;
 451         uint32_t nr_remaining = nr_result;
 452         time_t last_mtime = 0;
 453
 454         if (progress > pack_to_stdout)
 455                 progress_state = start_progress("Writing objects", nr_result);
 456         written_list = xmalloc(nr_objects * sizeof(*written_list));
 457
 458         do {
 459                 unsigned char sha1[20];
 460                 char *pack_tmp_name = NULL;
 461
 462                 if (pack_to_stdout) {
 463                         f = sha1fd_throughput(1, "<stdout>", progress_state);
 464                 } else {
 465                         char tmpname[PATH_MAX];
 466                         int fd;
 467                         snprintf(tmpname, sizeof(tmpname),
 468                                  "%s/pack/tmp_pack_XXXXXX", get_object_directory());
 469                         fd = xmkstemp(tmpname);
 470                         pack_tmp_name = xstrdup(tmpname);
 471                         f = sha1fd(fd, pack_tmp_name);
 472                 }
 473
 474                 hdr.hdr_signature = htonl(PACK_SIGNATURE);
 475                 hdr.hdr_version = htonl(PACK_VERSION);
 476                 hdr.hdr_entries = htonl(nr_remaining);
 477                 sha1write(f, &hdr, sizeof(hdr));
 478                 offset = sizeof(hdr);
 479                 nr_written = 0;
 480                 for (; i < nr_objects; i++) {
 481                         if (!write_one(f, objects + i, &offset))
 482                                 break;
 483                         display_progress(progress_state, written);
 484                 }
 485
 486                 /*
 487                  * Did we write the wrong # entries in the header?
 488                  * If so, rewrite it like in fast-import
 489                  */
 490                 if (pack_to_stdout) {
 491                         sha1close(f, sha1, CSUM_CLOSE);
 492                 } else if (nr_written == nr_remaining) {
 493                         sha1close(f, sha1, CSUM_FSYNC);
 494                 } else {
 495                         int fd = sha1close(f, sha1, 0);
 496                         fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 497                                                  nr_written, sha1, offset);
 498                         close(fd);
 499                 }
 500
 501                 if (!pack_to_stdout) {
 502                         mode_t mode = umask(0);
 503                         struct stat st;
 504                         char *idx_tmp_name, tmpname[PATH_MAX];
 505
 506                         umask(mode);
 507                         mode = 0444 & ~mode;
 508
 509                         idx_tmp_name = write_idx_file(NULL, written_list,
 510                                                       nr_written, sha1);
 511
 512                         snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
 513                                  base_name, sha1_to_hex(sha1));
 514                         if (adjust_perm(pack_tmp_name, mode))
 515                                 die("unable to make temporary pack file readable: %s",
 516                                     strerror(errno));
 517                         if (rename(pack_tmp_name, tmpname))
 518                                 die("unable to rename temporary pack file: %s",
 519                                     strerror(errno));
 520
 521                         /*
 522                          * Packs are runtime accessed in their mtime
 523                          * order since newer packs are more likely to contain
 524                          * younger objects.  So if we are creating multiple
 525                          * packs then we should modify the mtime of later ones
 526                          * to preserve this property.
 527                          */
 528                         if (stat(tmpname, &st) < 0) {
 529                                 warning("failed to stat %s: %s",
 530                                         tmpname, strerror(errno));
 531                         } else if (!last_mtime) {
 532                                 last_mtime = st.st_mtime;
 533                         } else {
 534                                 struct utimbuf utb;
 535                                 utb.actime = st.st_atime;
 536                                 utb.modtime = --last_mtime;
 537                                 if (utime(tmpname, &utb) < 0)
 538                                         warning("failed utime() on %s: %s",
 539                                                 tmpname, strerror(errno));
 540                         }
 541
 542                         snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
 543                                  base_name, sha1_to_hex(sha1));
 544                         if (adjust_perm(idx_tmp_name, mode))
 545                                 die("unable to make temporary index file readable: %s",
 546                                     strerror(errno));
 547                         if (rename(idx_tmp_name, tmpname))
 548                                 die("unable to rename temporary index file: %s",
 549                                     strerror(errno));
 550
 551                         free(idx_tmp_name);
 552                         free(pack_tmp_name);
 553                         puts(sha1_to_hex(sha1));
 554                 }
 555
 556                 /* mark written objects as written to previous pack */
 557                 for (j = 0; j < nr_written; j++) {
 558                         written_list[j]->offset = (off_t)-1;
 559                 }
 560                 nr_remaining -= nr_written;
 561         } while (nr_remaining && i < nr_objects);
 562
 563         free(written_list);
 564         stop_progress(&progress_state);
 565         if (written != nr_result)
 566                 die("wrote %"PRIu32" objects while expecting %"PRIu32,
 567                         written, nr_result);
 568         /*
 569          * We have scanned through [0 ... i).  Since we have written
 570          * the correct number of objects,  the remaining [i ... nr_objects)
 571          * items must be either already written (due to out-of-order delta base)
 572          * or a preferred base.  Count those which are neither and complain if any.
 573          */
 574         for (j = 0; i < nr_objects; i++) {
 575                 struct object_entry *e = objects + i;
 576                 j += !e->idx.offset && !e->preferred_base;
 577         }
 578         if (j)
 579                 die("wrote %"PRIu32" objects as expected but %"PRIu32
 580                         " unwritten", written, j);
 581 }
 582
 583 static int locate_object_entry_hash(const unsigned char *sha1)
 584 {
 585         int i;
 586         unsigned int ui;
 587         memcpy(&ui, sha1, sizeof(unsigned int));
 588         i = ui % object_ix_hashsz;
 589         while (0 < object_ix[i]) {
 590                 if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 591                         return i;
 592                 if (++i == object_ix_hashsz)
 593                         i = 0;
 594         }
 595         return -1 - i;
 596 }
 597
 598 static struct object_entry *locate_object_entry(const unsigned char *sha1)
 599 {
 600         int i;
 601
 602         if (!object_ix_hashsz)
 603                 return NULL;
 604
 605         i = locate_object_entry_hash(sha1);
 606         if (0 <= i)
 607                 return &objects[object_ix[i]-1];
 608         return NULL;
 609 }
 610
 611 static void rehash_objects(void)
 612 {
 613         uint32_t i;
 614         struct object_entry *oe;
 615
 616         object_ix_hashsz = nr_objects * 3;
 617         if (object_ix_hashsz < 1024)
 618                 object_ix_hashsz = 1024;
 619         object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 620         memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 621         for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 622                 int ix = locate_object_entry_hash(oe->idx.sha1);
 623                 if (0 <= ix)
 624                         continue;
 625                 ix = -1 - ix;
 626                 object_ix[ix] = i + 1;
 627         }
 628 }
 629
 630 static unsigned name_hash(const char *name)
 631 {
 632         unsigned char c;
 633         unsigned hash = 0;
 634
 635         if (!name)
 636                 return 0;
 637
 638         /*
 639          * This effectively just creates a sortable number from the
 640          * last sixteen non-whitespace characters. Last characters
 641          * count "most", so things that end in ".c" sort together.
 642          */
 643         while ((c = *name++) != 0) {
 644                 if (isspace(c))
 645                         continue;
 646                 hash = (hash >> 2) + (c << 24);
 647         }
 648         return hash;
 649 }
 650
 651 static void setup_delta_attr_check(struct git_attr_check *check)
 652 {
 653         static struct git_attr *attr_delta;
 654
 655         if (!attr_delta)
 656                 attr_delta = git_attr("delta", 5);
 657
 658         check[0].attr = attr_delta;
 659 }
 660
 661 static int no_try_delta(const char *path)
 662 {
 663         struct git_attr_check check[1];
 664
 665         setup_delta_attr_check(check);
 666         if (git_checkattr(path, ARRAY_SIZE(check), check))
 667                 return 0;
 668         if (ATTR_FALSE(check->value))
 669                 return 1;
 670         return 0;
 671 }
 672
 673 static int add_object_entry(const unsigned char *sha1, enum object_type type,
 674                             const char *name, int exclude)
 675 {
 676         struct object_entry *entry;
 677         struct packed_git *p, *found_pack = NULL;
 678         off_t found_offset = 0;
 679         int ix;
 680         unsigned hash = name_hash(name);
 681
 682         ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 683         if (ix >= 0) {
 684                 if (exclude) {
 685                         entry = objects + object_ix[ix] - 1;
 686                         if (!entry->preferred_base)
 687                                 nr_result--;
 688                         entry->preferred_base = 1;
 689                 }
 690                 return 0;
 691         }
 692
 693         for (p = packed_git; p; p = p->next) {
 694                 off_t offset = find_pack_entry_one(sha1, p);
 695                 if (offset) {
 696                         if (!found_pack) {
 697                                 found_offset = offset;
 698                                 found_pack = p;
 699                         }
 700                         if (exclude)
 701                                 break;
 702                         if (incremental)
 703                                 return 0;
 704                         if (local && !p->pack_local)
 705                                 return 0;
 706                 }
 707         }
 708
 709         if (nr_objects >= nr_alloc) {
 710                 nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 711                 objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 712         }
 713
 714         entry = objects + nr_objects++;
 715         memset(entry, 0, sizeof(*entry));
 716         hashcpy(entry->idx.sha1, sha1);
 717         entry->hash = hash;
 718         if (type)
 719                 entry->type = type;
 720         if (exclude)
 721                 entry->preferred_base = 1;
 722         else
 723                 nr_result++;
 724         if (found_pack) {
 725                 entry->in_pack = found_pack;
 726                 entry->in_pack_offset = found_offset;
 727         }
 728
 729         if (object_ix_hashsz * 3 <= nr_objects * 4)
 730                 rehash_objects();
 731         else
 732                 object_ix[-1 - ix] = nr_objects;
 733
 734         display_progress(progress_state, nr_objects);
 735
 736         if (name && no_try_delta(name))
 737                 entry->no_try_delta = 1;
 738
 739         return 1;
 740 }
 741
 742 struct pbase_tree_cache {
 743         unsigned char sha1[20];
 744         int ref;
 745         int temporary;
 746         void *tree_data;
 747         unsigned long tree_size;
 748 };
 749
 750 static struct pbase_tree_cache *(pbase_tree_cache[256]);
 751 static int pbase_tree_cache_ix(const unsigned char *sha1)
 752 {
 753         return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 754 }
 755 static int pbase_tree_cache_ix_incr(int ix)
 756 {
 757         return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 758 }
 759
 760 static struct pbase_tree {
 761         struct pbase_tree *next;
 762         /* This is a phony "cache" entry; we are not
 763          * going to evict it nor find it through _get()
 764          * mechanism -- this is for the toplevel node that
 765          * would almost always change with any commit.
 766          */
 767         struct pbase_tree_cache pcache;
 768 } *pbase_tree;
 769
 770 static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 771 {
 772         struct pbase_tree_cache *ent, *nent;
 773         void *data;
 774         unsigned long size;
 775         enum object_type type;
 776         int neigh;
 777         int my_ix = pbase_tree_cache_ix(sha1);
 778         int available_ix = -1;
 779
 780         /* pbase-tree-cache acts as a limited hashtable.
 781          * your object will be found at your index or within a few
 782          * slots after that slot if it is cached.
 783          */
 784         for (neigh = 0; neigh < 8; neigh++) {
 785                 ent = pbase_tree_cache[my_ix];
 786                 if (ent && !hashcmp(ent->sha1, sha1)) {
 787                         ent->ref++;
 788                         return ent;
 789                 }
 790                 else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 791                          ((0 <= available_ix) &&
 792                           (!ent && pbase_tree_cache[available_ix])))
 793                         available_ix = my_ix;
 794                 if (!ent)
 795                         break;
 796                 my_ix = pbase_tree_cache_ix_incr(my_ix);
 797         }
 798
 799         /* Did not find one.  Either we got a bogus request or
 800          * we need to read and perhaps cache.
 801          */
 802         data = read_sha1_file(sha1, &type, &size);
 803         if (!data)
 804                 return NULL;
 805         if (type != OBJ_TREE) {
 806                 free(data);
 807                 return NULL;
 808         }
 809
 810         /* We need to either cache or return a throwaway copy */
 811
 812         if (available_ix < 0)
 813                 ent = NULL;
 814         else {
 815                 ent = pbase_tree_cache[available_ix];
 816                 my_ix = available_ix;
 817         }
 818
 819         if (!ent) {
 820                 nent = xmalloc(sizeof(*nent));
 821                 nent->temporary = (available_ix < 0);
 822         }
 823         else {
 824                 /* evict and reuse */
 825                 free(ent->tree_data);
 826                 nent = ent;
 827         }
 828         hashcpy(nent->sha1, sha1);
 829         nent->tree_data = data;
 830         nent->tree_size = size;
 831         nent->ref = 1;
 832         if (!nent->temporary)
 833                 pbase_tree_cache[my_ix] = nent;
 834         return nent;
 835 }
 836
 837 static void pbase_tree_put(struct pbase_tree_cache *cache)
 838 {
 839         if (!cache->temporary) {
 840                 cache->ref--;
 841                 return;
 842         }
 843         free(cache->tree_data);
 844         free(cache);
 845 }
 846
 847 static int name_cmp_len(const char *name)
 848 {
 849         int i;
 850         for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 851                 ;
 852         return i;
 853 }
 854
 855 static void add_pbase_object(struct tree_desc *tree,
 856                              const char *name,
 857                              int cmplen,
 858                              const char *fullname)
 859 {
 860         struct name_entry entry;
 861         int cmp;
 862
 863         while (tree_entry(tree,&entry)) {
 864                 if (S_ISGITLINK(entry.mode))
 865                         continue;
 866                 cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
 867                       memcmp(name, entry.path, cmplen);
 868                 if (cmp > 0)
 869                         continue;
 870                 if (cmp < 0)
 871                         return;
 872                 if (name[cmplen] != '/') {
 873                         add_object_entry(entry.sha1,
 874                                          object_type(entry.mode),
 875                                          fullname, 1);
 876                         return;
 877                 }
 878                 if (S_ISDIR(entry.mode)) {
 879                         struct tree_desc sub;
 880                         struct pbase_tree_cache *tree;
 881                         const char *down = name+cmplen+1;
 882                         int downlen = name_cmp_len(down);
 883
 884                         tree = pbase_tree_get(entry.sha1);
 885                         if (!tree)
 886                                 return;
 887                         init_tree_desc(&sub, tree->tree_data, tree->tree_size);
 888
 889                         add_pbase_object(&sub, down, downlen, fullname);
 890                         pbase_tree_put(tree);
 891                 }
 892         }
 893 }
 894
 895 static unsigned *done_pbase_paths;
 896 static int done_pbase_paths_num;
 897 static int done_pbase_paths_alloc;
 898 static int done_pbase_path_pos(unsigned hash)
 899 {
 900         int lo = 0;
 901         int hi = done_pbase_paths_num;
 902         while (lo < hi) {
 903                 int mi = (hi + lo) / 2;
 904                 if (done_pbase_paths[mi] == hash)
 905                         return mi;
 906                 if (done_pbase_paths[mi] < hash)
 907                         hi = mi;
 908                 else
 909                         lo = mi + 1;
 910         }
 911         return -lo-1;
 912 }
 913
 914 static int check_pbase_path(unsigned hash)
 915 {
 916         int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 917         if (0 <= pos)
 918                 return 1;
 919         pos = -pos - 1;
 920         if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 921                 done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 922                 done_pbase_paths = xrealloc(done_pbase_paths,
 923                                             done_pbase_paths_alloc *
 924                                             sizeof(unsigned));
 925         }
 926         done_pbase_paths_num++;
 927         if (pos < done_pbase_paths_num)
 928                 memmove(done_pbase_paths + pos + 1,
 929                         done_pbase_paths + pos,
 930                         (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 931         done_pbase_paths[pos] = hash;
 932         return 0;
 933 }
 934
 935 static void add_preferred_base_object(const char *name)
 936 {
 937         struct pbase_tree *it;
 938         int cmplen;
 939         unsigned hash = name_hash(name);
 940
 941         if (!num_preferred_base || check_pbase_path(hash))
 942                 return;
 943
 944         cmplen = name_cmp_len(name);
 945         for (it = pbase_tree; it; it = it->next) {
 946                 if (cmplen == 0) {
 947                         add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
 948                 }
 949                 else {
 950                         struct tree_desc tree;
 951                         init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
 952                         add_pbase_object(&tree, name, cmplen, name);
 953                 }
 954         }
 955 }
 956
 957 static void add_preferred_base(unsigned char *sha1)
 958 {
 959         struct pbase_tree *it;
 960         void *data;
 961         unsigned long size;
 962         unsigned char tree_sha1[20];
 963
 964         if (window <= num_preferred_base++)
 965                 return;
 966
 967         data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
 968         if (!data)
 969                 return;
 970
 971         for (it = pbase_tree; it; it = it->next) {
 972                 if (!hashcmp(it->pcache.sha1, tree_sha1)) {
 973                         free(data);
 974                         return;
 975                 }
 976         }
 977
 978         it = xcalloc(1, sizeof(*it));
 979         it->next = pbase_tree;
 980         pbase_tree = it;
 981
 982         hashcpy(it->pcache.sha1, tree_sha1);
 983         it->pcache.tree_data = data;
 984         it->pcache.tree_size = size;
 985 }
 986
 987 static void check_object(struct object_entry *entry)
 988 {
 989         if (entry->in_pack) {
 990                 struct packed_git *p = entry->in_pack;
 991                 struct pack_window *w_curs = NULL;
 992                 const unsigned char *base_ref = NULL;
 993                 struct object_entry *base_entry;
 994                 unsigned long used, used_0;
 995                 unsigned int avail;
 996                 off_t ofs;
 997                 unsigned char *buf, c;
 998
 999                 buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1000
1001                 /*
1002                  * We want in_pack_type even if we do not reuse delta
1003                  * since non-delta representations could still be reused.
1004                  */
1005                 used = unpack_object_header_gently(buf, avail,
1006                                                    &entry->in_pack_type,
1007                                                    &entry->size);
1008
1009                 /*
1010                  * Determine if this is a delta and if so whether we can
1011                  * reuse it or not.  Otherwise let's find out as cheaply as
1012                  * possible what the actual type and size for this object is.
1013                  */
1014                 switch (entry->in_pack_type) {
1015                 default:
1016                         /* Not a delta hence we've already got all we need. */
1017                         entry->type = entry->in_pack_type;
1018                         entry->in_pack_header_size = used;
1019                         unuse_pack(&w_curs);
1020                         return;
1021                 case OBJ_REF_DELTA:
1022                         if (reuse_delta && !entry->preferred_base)
1023                                 base_ref = use_pack(p, &w_curs,
1024                                                 entry->in_pack_offset + used, NULL);
1025                         entry->in_pack_header_size = used + 20;
1026                         break;
1027                 case OBJ_OFS_DELTA:
1028                         buf = use_pack(p, &w_curs,
1029                                        entry->in_pack_offset + used, NULL);
1030                         used_0 = 0;
1031                         c = buf[used_0++];
1032                         ofs = c & 127;
1033                         while (c & 128) {
1034                                 ofs += 1;
1035                                 if (!ofs || MSB(ofs, 7))
1036                                         die("delta base offset overflow in pack for %s",
1037                                             sha1_to_hex(entry->idx.sha1));
1038                                 c = buf[used_0++];
1039                                 ofs = (ofs << 7) + (c & 127);
1040                         }
1041                         ofs = entry->in_pack_offset - ofs;
1042                         if (ofs <= 0 || ofs >= entry->in_pack_offset)
1043                                 die("delta base offset out of bound for %s",
1044                                     sha1_to_hex(entry->idx.sha1));
1045                         if (reuse_delta && !entry->preferred_base) {
1046                                 struct revindex_entry *revidx;
1047                                 revidx = find_pack_revindex(p, ofs);
1048                                 base_ref = nth_packed_object_sha1(p, revidx->nr);
1049                         }
1050                         entry->in_pack_header_size = used + used_0;
1051                         break;
1052                 }
1053
1054                 if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1055                         /*
1056                          * If base_ref was set above that means we wish to
1057                          * reuse delta data, and we even found that base
1058                          * in the list of objects we want to pack. Goodie!
1059                          *
1060                          * Depth value does not matter - find_deltas() will
1061                          * never consider reused delta as the base object to
1062                          * deltify other objects against, in order to avoid
1063                          * circular deltas.
1064                          */
1065                         entry->type = entry->in_pack_type;
1066                         entry->delta = base_entry;
1067                         entry->delta_sibling = base_entry->delta_child;
1068                         base_entry->delta_child = entry;
1069                         unuse_pack(&w_curs);
1070                         return;
1071                 }
1072
1073                 if (entry->type) {
1074                         /*
1075                          * This must be a delta and we already know what the
1076                          * final object type is.  Let's extract the actual
1077                          * object size from the delta header.
1078                          */
1079                         entry->size = get_size_from_delta(p, &w_curs,
1080                                         entry->in_pack_offset + entry->in_pack_header_size);
1081                         unuse_pack(&w_curs);
1082                         return;
1083                 }
1084
1085                 /*
1086                  * No choice but to fall back to the recursive delta walk
1087                  * with sha1_object_info() to find about the object type
1088                  * at this point...
1089                  */
1090                 unuse_pack(&w_curs);
1091         }
1092
1093         entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1094         /*
1095          * The error condition is checked in prepare_pack().  This is
1096          * to permit a missing preferred base object to be ignored
1097          * as a preferred base.  Doing so can result in a larger
1098          * pack file, but the transfer will still take place.
1099          */
1100 }
1101
1102 static int pack_offset_sort(const void *_a, const void *_b)
1103 {
1104         const struct object_entry *a = *(struct object_entry **)_a;
1105         const struct object_entry *b = *(struct object_entry **)_b;
1106
1107         /* avoid filesystem trashing with loose objects */
1108         if (!a->in_pack && !b->in_pack)
1109                 return hashcmp(a->idx.sha1, b->idx.sha1);
1110
1111         if (a->in_pack < b->in_pack)
1112                 return -1;
1113         if (a->in_pack > b->in_pack)
1114                 return 1;
1115         return a->in_pack_offset < b->in_pack_offset ? -1 :
1116                         (a->in_pack_offset > b->in_pack_offset);
1117 }
1118
1119 static void get_object_details(void)
1120 {
1121         uint32_t i;
1122         struct object_entry **sorted_by_offset;
1123
1124         sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1125         for (i = 0; i < nr_objects; i++)
1126                 sorted_by_offset[i] = objects + i;
1127         qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1128
1129         for (i = 0; i < nr_objects; i++)
1130                 check_object(sorted_by_offset[i]);
1131
1132         free(sorted_by_offset);
1133 }
1134
1135 /*
1136  * We search for deltas in a list sorted by type, by filename hash, and then
1137  * by size, so that we see progressively smaller and smaller files.
1138  * That's because we prefer deltas to be from the bigger file
1139  * to the smaller -- deletes are potentially cheaper, but perhaps
1140  * more importantly, the bigger file is likely the more recent
1141  * one.  The deepest deltas are therefore the oldest objects which are
1142  * less susceptible to be accessed often.
1143  */
1144 static int type_size_sort(const void *_a, const void *_b)
1145 {
1146         const struct object_entry *a = *(struct object_entry **)_a;
1147         const struct object_entry *b = *(struct object_entry **)_b;
1148
1149         if (a->type > b->type)
1150                 return -1;
1151         if (a->type < b->type)
1152                 return 1;
1153         if (a->hash > b->hash)
1154                 return -1;
1155         if (a->hash < b->hash)
1156                 return 1;
1157         if (a->preferred_base > b->preferred_base)
1158                 return -1;
1159         if (a->preferred_base < b->preferred_base)
1160                 return 1;
1161         if (a->size > b->size)
1162                 return -1;
1163         if (a->size < b->size)
1164                 return 1;
1165         return a < b ? -1 : (a > b);  /* newest first */
1166 }
1167
1168 struct unpacked {
1169         struct object_entry *entry;
1170         void *data;
1171         struct delta_index *index;
1172         unsigned depth;
1173 };
1174
1175 static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1176                            unsigned long delta_size)
1177 {
1178         if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1179                 return 0;
1180
1181         if (delta_size < cache_max_small_delta_size)
1182                 return 1;
1183
1184         /* cache delta, if objects are large enough compared to delta size */
1185         if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1186                 return 1;
1187
1188         return 0;
1189 }
1190
1191 #ifdef THREADED_DELTA_SEARCH
1192
1193 static pthread_mutex_t read_mutex = PTHREAD_MUTEX_INITIALIZER;
1194 #define read_lock()             pthread_mutex_lock(&read_mutex)
1195 #define read_unlock()           pthread_mutex_unlock(&read_mutex)
1196
1197 static pthread_mutex_t cache_mutex = PTHREAD_MUTEX_INITIALIZER;
1198 #define cache_lock()            pthread_mutex_lock(&cache_mutex)
1199 #define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1200
1201 static pthread_mutex_t progress_mutex = PTHREAD_MUTEX_INITIALIZER;
1202 #define progress_lock()         pthread_mutex_lock(&progress_mutex)
1203 #define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1204
1205 #else
1206
1207 #define read_lock()             (void)0
1208 #define read_unlock()           (void)0
1209 #define cache_lock()            (void)0
1210 #define cache_unlock()          (void)0
1211 #define progress_lock()         (void)0
1212 #define progress_unlock()       (void)0
1213
1214 #endif
1215
1216 static int try_delta(struct unpacked *trg, struct unpacked *src,
1217                      unsigned max_depth, unsigned long *mem_usage)
1218 {
1219         struct object_entry *trg_entry = trg->entry;
1220         struct object_entry *src_entry = src->entry;
1221         unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1222         unsigned ref_depth;
1223         enum object_type type;
1224         void *delta_buf;
1225
1226         /* Don't bother doing diffs between different types */
1227         if (trg_entry->type != src_entry->type)
1228                 return -1;
1229
1230         /*
1231          * We do not bother to try a delta that we discarded
1232          * on an earlier try, but only when reusing delta data.
1233          */
1234         if (reuse_delta && trg_entry->in_pack &&
1235             trg_entry->in_pack == src_entry->in_pack &&
1236             trg_entry->in_pack_type != OBJ_REF_DELTA &&
1237             trg_entry->in_pack_type != OBJ_OFS_DELTA)
1238                 return 0;
1239
1240         /* Let's not bust the allowed depth. */
1241         if (src->depth >= max_depth)
1242                 return 0;
1243
1244         /* Now some size filtering heuristics. */
1245         trg_size = trg_entry->size;
1246         if (!trg_entry->delta) {
1247                 max_size = trg_size/2 - 20;
1248                 ref_depth = 1;
1249         } else {
1250                 max_size = trg_entry->delta_size;
1251                 ref_depth = trg->depth;
1252         }
1253         max_size = max_size * (max_depth - src->depth) /
1254                                                 (max_depth - ref_depth + 1);
1255         if (max_size == 0)
1256                 return 0;
1257         src_size = src_entry->size;
1258         sizediff = src_size < trg_size ? trg_size - src_size : 0;
1259         if (sizediff >= max_size)
1260                 return 0;
1261         if (trg_size < src_size / 32)
1262                 return 0;
1263
1264         /* Load data if not already done */
1265         if (!trg->data) {
1266                 read_lock();
1267                 trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1268                 read_unlock();
1269                 if (!trg->data)
1270                         die("object %s cannot be read",
1271                             sha1_to_hex(trg_entry->idx.sha1));
1272                 if (sz != trg_size)
1273                         die("object %s inconsistent object length (%lu vs %lu)",
1274                             sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1275                 *mem_usage += sz;
1276         }
1277         if (!src->data) {
1278                 read_lock();
1279                 src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1280                 read_unlock();
1281                 if (!src->data)
1282                         die("object %s cannot be read",
1283                             sha1_to_hex(src_entry->idx.sha1));
1284                 if (sz != src_size)
1285                         die("object %s inconsistent object length (%lu vs %lu)",
1286                             sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1287                 *mem_usage += sz;
1288         }
1289         if (!src->index) {
1290                 src->index = create_delta_index(src->data, src_size);
1291                 if (!src->index) {
1292                         static int warned = 0;
1293                         if (!warned++)
1294                                 warning("suboptimal pack - out of memory");
1295                         return 0;
1296                 }
1297                 *mem_usage += sizeof_delta_index(src->index);
1298         }
1299
1300         delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1301         if (!delta_buf)
1302                 return 0;
1303
1304         if (trg_entry->delta) {
1305                 /* Prefer only shallower same-sized deltas. */
1306                 if (delta_size == trg_entry->delta_size &&
1307                     src->depth + 1 >= trg->depth) {
1308                         free(delta_buf);
1309                         return 0;
1310                 }
1311         }
1312
1313         /*
1314          * Handle memory allocation outside of the cache
1315          * accounting lock.  Compiler will optimize the strangeness
1316          * away when THREADED_DELTA_SEARCH is not defined.
1317          */
1318         free(trg_entry->delta_data);
1319         cache_lock();
1320         if (trg_entry->delta_data) {
1321                 delta_cache_size -= trg_entry->delta_size;
1322                 trg_entry->delta_data = NULL;
1323         }
1324         if (delta_cacheable(src_size, trg_size, delta_size)) {
1325                 delta_cache_size += delta_size;
1326                 cache_unlock();
1327                 trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1328         } else {
1329                 cache_unlock();
1330                 free(delta_buf);
1331         }
1332
1333         trg_entry->delta = src_entry;
1334         trg_entry->delta_size = delta_size;
1335         trg->depth = src->depth + 1;
1336
1337         return 1;
1338 }
1339
1340 static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1341 {
1342         struct object_entry *child = me->delta_child;
1343         unsigned int m = n;
1344         while (child) {
1345                 unsigned int c = check_delta_limit(child, n + 1);
1346                 if (m < c)
1347                         m = c;
1348                 child = child->delta_sibling;
1349         }
1350         return m;
1351 }
1352
1353 static unsigned long free_unpacked(struct unpacked *n)
1354 {
1355         unsigned long freed_mem = sizeof_delta_index(n->index);
1356         free_delta_index(n->index);
1357         n->index = NULL;
1358         if (n->data) {
1359                 freed_mem += n->entry->size;
1360                 free(n->data);
1361                 n->data = NULL;
1362         }
1363         n->entry = NULL;
1364         n->depth = 0;
1365         return freed_mem;
1366 }
1367
1368 static void find_deltas(struct object_entry **list, unsigned *list_size,
1369                         int window, int depth, unsigned *processed)
1370 {
1371         uint32_t i, idx = 0, count = 0;
1372         struct unpacked *array;
1373         unsigned long mem_usage = 0;
1374
1375         array = xcalloc(window, sizeof(struct unpacked));
1376
1377         for (;;) {
1378                 struct object_entry *entry;
1379                 struct unpacked *n = array + idx;
1380                 int j, max_depth, best_base = -1;
1381
1382                 progress_lock();
1383                 if (!*list_size) {
1384                         progress_unlock();
1385                         break;
1386                 }
1387                 entry = *list++;
1388                 (*list_size)--;
1389                 if (!entry->preferred_base) {
1390                         (*processed)++;
1391                         display_progress(progress_state, *processed);
1392                 }
1393                 progress_unlock();
1394
1395                 mem_usage -= free_unpacked(n);
1396                 n->entry = entry;
1397
1398                 while (window_memory_limit &&
1399                        mem_usage > window_memory_limit &&
1400                        count > 1) {
1401                         uint32_t tail = (idx + window - count) % window;
1402                         mem_usage -= free_unpacked(array + tail);
1403                         count--;
1404                 }
1405
1406                 /* We do not compute delta to *create* objects we are not
1407                  * going to pack.
1408                  */
1409                 if (entry->preferred_base)
1410                         goto next;
1411
1412                 /*
1413                  * If the current object is at pack edge, take the depth the
1414                  * objects that depend on the current object into account
1415                  * otherwise they would become too deep.
1416                  */
1417                 max_depth = depth;
1418                 if (entry->delta_child) {
1419                         max_depth -= check_delta_limit(entry, 0);
1420                         if (max_depth <= 0)
1421                                 goto next;
1422                 }
1423
1424                 j = window;
1425                 while (--j > 0) {
1426                         int ret;
1427                         uint32_t other_idx = idx + j;
1428                         struct unpacked *m;
1429                         if (other_idx >= window)
1430                                 other_idx -= window;
1431                         m = array + other_idx;
1432                         if (!m->entry)
1433                                 break;
1434                         ret = try_delta(n, m, max_depth, &mem_usage);
1435                         if (ret < 0)
1436                                 break;
1437                         else if (ret > 0)
1438                                 best_base = other_idx;
1439                 }
1440
1441                 /*
1442                  * If we decided to cache the delta data, then it is best
1443                  * to compress it right away.  First because we have to do
1444                  * it anyway, and doing it here while we're threaded will
1445                  * save a lot of time in the non threaded write phase,
1446                  * as well as allow for caching more deltas within
1447                  * the same cache size limit.
1448                  * ...
1449                  * But only if not writing to stdout, since in that case
1450                  * the network is most likely throttling writes anyway,
1451                  * and therefore it is best to go to the write phase ASAP
1452                  * instead, as we can afford spending more time compressing
1453                  * between writes at that moment.
1454                  */
1455                 if (entry->delta_data && !pack_to_stdout) {
1456                         entry->z_delta_size = do_compress(&entry->delta_data,
1457                                                           entry->delta_size);
1458                         cache_lock();
1459                         delta_cache_size -= entry->delta_size;
1460                         delta_cache_size += entry->z_delta_size;
1461                         cache_unlock();
1462                 }
1463
1464                 /* if we made n a delta, and if n is already at max
1465                  * depth, leaving it in the window is pointless.  we
1466                  * should evict it first.
1467                  */
1468                 if (entry->delta && max_depth <= n->depth)
1469                         continue;
1470
1471                 /*
1472                  * Move the best delta base up in the window, after the
1473                  * currently deltified object, to keep it longer.  It will
1474                  * be the first base object to be attempted next.
1475                  */
1476                 if (entry->delta) {
1477                         struct unpacked swap = array[best_base];
1478                         int dist = (window + idx - best_base) % window;
1479                         int dst = best_base;
1480                         while (dist--) {
1481                                 int src = (dst + 1) % window;
1482                                 array[dst] = array[src];
1483                                 dst = src;
1484                         }
1485                         array[dst] = swap;
1486                 }
1487
1488                 next:
1489                 idx++;
1490                 if (count + 1 < window)
1491                         count++;
1492                 if (idx >= window)
1493                         idx = 0;
1494         }
1495
1496         for (i = 0; i < window; ++i) {
1497                 free_delta_index(array[i].index);
1498                 free(array[i].data);
1499         }
1500         free(array);
1501 }
1502
1503 #ifdef THREADED_DELTA_SEARCH
1504
1505 /*
1506  * The main thread waits on the condition that (at least) one of the workers
1507  * has stopped working (which is indicated in the .working member of
1508  * struct thread_params).
1509  * When a work thread has completed its work, it sets .working to 0 and
1510  * signals the main thread and waits on the condition that .data_ready
1511  * becomes 1.
1512  */
1513
1514 struct thread_params {
1515         pthread_t thread;
1516         struct object_entry **list;
1517         unsigned list_size;
1518         unsigned remaining;
1519         int window;
1520         int depth;
1521         int working;
1522         int data_ready;
1523         pthread_mutex_t mutex;
1524         pthread_cond_t cond;
1525         unsigned *processed;
1526 };
1527
1528 static pthread_cond_t progress_cond = PTHREAD_COND_INITIALIZER;
1529
1530 static void *threaded_find_deltas(void *arg)
1531 {
1532         struct thread_params *me = arg;
1533
1534         while (me->remaining) {
1535                 find_deltas(me->list, &me->remaining,
1536                             me->window, me->depth, me->processed);
1537
1538                 progress_lock();
1539                 me->working = 0;
1540                 pthread_cond_signal(&progress_cond);
1541                 progress_unlock();
1542
1543                 /*
1544                  * We must not set ->data_ready before we wait on the
1545                  * condition because the main thread may have set it to 1
1546                  * before we get here. In order to be sure that new
1547                  * work is available if we see 1 in ->data_ready, it
1548                  * was initialized to 0 before this thread was spawned
1549                  * and we reset it to 0 right away.
1550                  */
1551                 pthread_mutex_lock(&me->mutex);
1552                 while (!me->data_ready)
1553                         pthread_cond_wait(&me->cond, &me->mutex);
1554                 me->data_ready = 0;
1555                 pthread_mutex_unlock(&me->mutex);
1556         }
1557         /* leave ->working 1 so that this doesn't get more work assigned */
1558         return NULL;
1559 }
1560
1561 static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1562                            int window, int depth, unsigned *processed)
1563 {
1564         struct thread_params p[delta_search_threads];
1565         int i, ret, active_threads = 0;
1566
1567         if (delta_search_threads <= 1) {
1568                 find_deltas(list, &list_size, window, depth, processed);
1569                 return;
1570         }
1571
1572         /* Partition the work amongst work threads. */
1573         for (i = 0; i < delta_search_threads; i++) {
1574                 unsigned sub_size = list_size / (delta_search_threads - i);
1575
1576                 p[i].window = window;
1577                 p[i].depth = depth;
1578                 p[i].processed = processed;
1579                 p[i].working = 1;
1580                 p[i].data_ready = 0;
1581
1582                 /* try to split chunks on "path" boundaries */
1583                 while (sub_size && sub_size < list_size &&
1584                        list[sub_size]->hash &&
1585                        list[sub_size]->hash == list[sub_size-1]->hash)
1586                         sub_size++;
1587
1588                 p[i].list = list;
1589                 p[i].list_size = sub_size;
1590                 p[i].remaining = sub_size;
1591
1592                 list += sub_size;
1593                 list_size -= sub_size;
1594         }
1595
1596         /* Start work threads. */
1597         for (i = 0; i < delta_search_threads; i++) {
1598                 if (!p[i].list_size)
1599                         continue;
1600                 pthread_mutex_init(&p[i].mutex, NULL);
1601                 pthread_cond_init(&p[i].cond, NULL);
1602                 ret = pthread_create(&p[i].thread, NULL,
1603                                      threaded_find_deltas, &p[i]);
1604                 if (ret)
1605                         die("unable to create thread: %s", strerror(ret));
1606                 active_threads++;
1607         }
1608
1609         /*
1610          * Now let's wait for work completion.  Each time a thread is done
1611          * with its work, we steal half of the remaining work from the
1612          * thread with the largest number of unprocessed objects and give
1613          * it to that newly idle thread.  This ensure good load balancing
1614          * until the remaining object list segments are simply too short
1615          * to be worth splitting anymore.
1616          */
1617         while (active_threads) {
1618                 struct thread_params *target = NULL;
1619                 struct thread_params *victim = NULL;
1620                 unsigned sub_size = 0;
1621
1622                 progress_lock();
1623                 for (;;) {
1624                         for (i = 0; !target && i < delta_search_threads; i++)
1625                                 if (!p[i].working)
1626                                         target = &p[i];
1627                         if (target)
1628                                 break;
1629                         pthread_cond_wait(&progress_cond, &progress_mutex);
1630                 }
1631
1632                 for (i = 0; i < delta_search_threads; i++)
1633                         if (p[i].remaining > 2*window &&
1634                             (!victim || victim->remaining < p[i].remaining))
1635                                 victim = &p[i];
1636                 if (victim) {
1637                         sub_size = victim->remaining / 2;
1638                         list = victim->list + victim->list_size - sub_size;
1639                         while (sub_size && list[0]->hash &&
1640                                list[0]->hash == list[-1]->hash) {
1641                                 list++;
1642                                 sub_size--;
1643                         }
1644                         if (!sub_size) {
1645                                 /*
1646                                  * It is possible for some "paths" to have
1647                                  * so many objects that no hash boundary
1648                                  * might be found.  Let's just steal the
1649                                  * exact half in that case.
1650                                  */
1651                                 sub_size = victim->remaining / 2;
1652                                 list -= sub_size;
1653                         }
1654                         target->list = list;
1655                         victim->list_size -= sub_size;
1656                         victim->remaining -= sub_size;
1657                 }
1658                 target->list_size = sub_size;
1659                 target->remaining = sub_size;
1660                 target->working = 1;
1661                 progress_unlock();
1662
1663                 pthread_mutex_lock(&target->mutex);
1664                 target->data_ready = 1;
1665                 pthread_cond_signal(&target->cond);
1666                 pthread_mutex_unlock(&target->mutex);
1667
1668                 if (!sub_size) {
1669                         pthread_join(target->thread, NULL);
1670                         pthread_cond_destroy(&target->cond);
1671                         pthread_mutex_destroy(&target->mutex);
1672                         active_threads--;
1673                 }
1674         }
1675 }
1676
1677 #else
1678 #define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
1679 #endif
1680
1681 static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1682 {
1683         unsigned char peeled[20];
1684
1685         if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
1686             !peel_ref(path, peeled)        && /* peelable? */
1687             !is_null_sha1(peeled)          && /* annotated tag? */
1688             locate_object_entry(peeled))      /* object packed? */
1689                 add_object_entry(sha1, OBJ_TAG, NULL, 0);
1690         return 0;
1691 }
1692
1693 static void prepare_pack(int window, int depth)
1694 {
1695         struct object_entry **delta_list;
1696         uint32_t i, nr_deltas;
1697         unsigned n;
1698
1699         get_object_details();
1700
1701         /*
1702          * If we're locally repacking then we need to be doubly careful
1703          * from now on in order to make sure no stealth corruption gets
1704          * propagated to the new pack.  Clients receiving streamed packs
1705          * should validate everything they get anyway so no need to incur
1706          * the additional cost here in that case.
1707          */
1708         if (!pack_to_stdout)
1709                 do_check_packed_object_crc = 1;
1710
1711         if (!nr_objects || !window || !depth)
1712                 return;
1713
1714         delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1715         nr_deltas = n = 0;
1716
1717         for (i = 0; i < nr_objects; i++) {
1718                 struct object_entry *entry = objects + i;
1719
1720                 if (entry->delta)
1721                         /* This happens if we decided to reuse existing
1722                          * delta from a pack.  "reuse_delta &&" is implied.
1723                          */
1724                         continue;
1725
1726                 if (entry->size < 50)
1727                         continue;
1728
1729                 if (entry->no_try_delta)
1730                         continue;
1731
1732                 if (!entry->preferred_base) {
1733                         nr_deltas++;
1734                         if (entry->type < 0)
1735                                 die("unable to get type of object %s",
1736                                     sha1_to_hex(entry->idx.sha1));
1737                 } else {
1738                         if (entry->type < 0) {
1739                                 /*
1740                                  * This object is not found, but we
1741                                  * don't have to include it anyway.
1742                                  */
1743                                 continue;
1744                         }
1745                 }
1746
1747                 delta_list[n++] = entry;
1748         }
1749
1750         if (nr_deltas && n > 1) {
1751                 unsigned nr_done = 0;
1752                 if (progress)
1753                         progress_state = start_progress("Compressing objects",
1754                                                         nr_deltas);
1755                 qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
1756                 ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
1757                 stop_progress(&progress_state);
1758                 if (nr_done != nr_deltas)
1759                         die("inconsistency with delta count");
1760         }
1761         free(delta_list);
1762 }
1763
1764 static int git_pack_config(const char *k, const char *v, void *cb)
1765 {
1766         if(!strcmp(k, "pack.window")) {
1767                 window = git_config_int(k, v);
1768                 return 0;
1769         }
1770         if (!strcmp(k, "pack.windowmemory")) {
1771                 window_memory_limit = git_config_ulong(k, v);
1772                 return 0;
1773         }
1774         if (!strcmp(k, "pack.depth")) {
1775                 depth = git_config_int(k, v);
1776                 return 0;
1777         }
1778         if (!strcmp(k, "pack.compression")) {
1779                 int level = git_config_int(k, v);
1780                 if (level == -1)
1781                         level = Z_DEFAULT_COMPRESSION;
1782                 else if (level < 0 || level > Z_BEST_COMPRESSION)
1783                         die("bad pack compression level %d", level);
1784                 pack_compression_level = level;
1785                 pack_compression_seen = 1;
1786                 return 0;
1787         }
1788         if (!strcmp(k, "pack.deltacachesize")) {
1789                 max_delta_cache_size = git_config_int(k, v);
1790                 return 0;
1791         }
1792         if (!strcmp(k, "pack.deltacachelimit")) {
1793                 cache_max_small_delta_size = git_config_int(k, v);
1794                 return 0;
1795         }
1796         if (!strcmp(k, "pack.threads")) {
1797                 delta_search_threads = git_config_int(k, v);
1798                 if (delta_search_threads < 0)
1799                         die("invalid number of threads specified (%d)",
1800                             delta_search_threads);
1801 #ifndef THREADED_DELTA_SEARCH
1802                 if (delta_search_threads != 1)
1803                         warning("no threads support, ignoring %s", k);
1804 #endif
1805                 return 0;
1806         }
1807         if (!strcmp(k, "pack.indexversion")) {
1808                 pack_idx_default_version = git_config_int(k, v);
1809                 if (pack_idx_default_version > 2)
1810                         die("bad pack.indexversion=%"PRIu32,
1811                                 pack_idx_default_version);
1812                 return 0;
1813         }
1814         if (!strcmp(k, "pack.packsizelimit")) {
1815                 pack_size_limit_cfg = git_config_ulong(k, v);
1816                 return 0;
1817         }
1818         return git_default_config(k, v, cb);
1819 }
1820
1821 static void read_object_list_from_stdin(void)
1822 {
1823         char line[40 + 1 + PATH_MAX + 2];
1824         unsigned char sha1[20];
1825
1826         for (;;) {
1827                 if (!fgets(line, sizeof(line), stdin)) {
1828                         if (feof(stdin))
1829                                 break;
1830                         if (!ferror(stdin))
1831                                 die("fgets returned NULL, not EOF, not error!");
1832                         if (errno != EINTR)
1833                                 die("fgets: %s", strerror(errno));
1834                         clearerr(stdin);
1835                         continue;
1836                 }
1837                 if (line[0] == '-') {
1838                         if (get_sha1_hex(line+1, sha1))
1839                                 die("expected edge sha1, got garbage:\n %s",
1840                                     line);
1841                         add_preferred_base(sha1);
1842                         continue;
1843                 }
1844                 if (get_sha1_hex(line, sha1))
1845                         die("expected sha1, got garbage:\n %s", line);
1846
1847                 add_preferred_base_object(line+41);
1848                 add_object_entry(sha1, 0, line+41, 0);
1849         }
1850 }
1851
1852 #define OBJECT_ADDED (1u<<20)
1853
1854 static void show_commit(struct commit *commit)
1855 {
1856         add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
1857         commit->object.flags |= OBJECT_ADDED;
1858 }
1859
1860 static void show_object(struct object_array_entry *p)
1861 {
1862         add_preferred_base_object(p->name);
1863         add_object_entry(p->item->sha1, p->item->type, p->name, 0);
1864         p->item->flags |= OBJECT_ADDED;
1865 }
1866
1867 static void show_edge(struct commit *commit)
1868 {
1869         add_preferred_base(commit->object.sha1);
1870 }
1871
1872 struct in_pack_object {
1873         off_t offset;
1874         struct object *object;
1875 };
1876
1877 struct in_pack {
1878         int alloc;
1879         int nr;
1880         struct in_pack_object *array;
1881 };
1882
1883 static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
1884 {
1885         in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
1886         in_pack->array[in_pack->nr].object = object;
1887         in_pack->nr++;
1888 }
1889
1890 /*
1891  * Compare the objects in the offset order, in order to emulate the
1892  * "git rev-list --objects" output that produced the pack originally.
1893  */
1894 static int ofscmp(const void *a_, const void *b_)
1895 {
1896         struct in_pack_object *a = (struct in_pack_object *)a_;
1897         struct in_pack_object *b = (struct in_pack_object *)b_;
1898
1899         if (a->offset < b->offset)
1900                 return -1;
1901         else if (a->offset > b->offset)
1902                 return 1;
1903         else
1904                 return hashcmp(a->object->sha1, b->object->sha1);
1905 }
1906
1907 static void add_objects_in_unpacked_packs(struct rev_info *revs)
1908 {
1909         struct packed_git *p;
1910         struct in_pack in_pack;
1911         uint32_t i;
1912
1913         memset(&in_pack, 0, sizeof(in_pack));
1914
1915         for (p = packed_git; p; p = p->next) {
1916                 const unsigned char *sha1;
1917                 struct object *o;
1918
1919                 for (i = 0; i < revs->num_ignore_packed; i++) {
1920                         if (matches_pack_name(p, revs->ignore_packed[i]))
1921                                 break;
1922                 }
1923                 if (revs->num_ignore_packed <= i)
1924                         continue;
1925                 if (open_pack_index(p))
1926                         die("cannot open pack index");
1927
1928                 ALLOC_GROW(in_pack.array,
1929                            in_pack.nr + p->num_objects,
1930                            in_pack.alloc);
1931
1932                 for (i = 0; i < p->num_objects; i++) {
1933                         sha1 = nth_packed_object_sha1(p, i);
1934                         o = lookup_unknown_object(sha1);
1935                         if (!(o->flags & OBJECT_ADDED))
1936                                 mark_in_pack_object(o, p, &in_pack);
1937                         o->flags |= OBJECT_ADDED;
1938                 }
1939         }
1940
1941         if (in_pack.nr) {
1942                 qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
1943                       ofscmp);
1944                 for (i = 0; i < in_pack.nr; i++) {
1945                         struct object *o = in_pack.array[i].object;
1946                         add_object_entry(o->sha1, o->type, "", 0);
1947                 }
1948         }
1949         free(in_pack.array);
1950 }
1951
1952 static void loosen_unused_packed_objects(struct rev_info *revs)
1953 {
1954         struct packed_git *p;
1955         uint32_t i;
1956         const unsigned char *sha1;
1957
1958         for (p = packed_git; p; p = p->next) {
1959                 for (i = 0; i < revs->num_ignore_packed; i++) {
1960                         if (matches_pack_name(p, revs->ignore_packed[i]))
1961                                 break;
1962                 }
1963                 if (revs->num_ignore_packed <= i)
1964                         continue;
1965
1966                 if (open_pack_index(p))
1967                         die("cannot open pack index");
1968
1969                 for (i = 0; i < p->num_objects; i++) {
1970                         sha1 = nth_packed_object_sha1(p, i);
1971                         if (!locate_object_entry(sha1))
1972                                 if (force_object_loose(sha1, p->mtime))
1973                                         die("unable to force loose object");
1974                 }
1975         }
1976 }
1977
1978 static void get_object_list(int ac, const char **av)
1979 {
1980         struct rev_info revs;
1981         char line[1000];
1982         int flags = 0;
1983
1984         init_revisions(&revs, NULL);
1985         save_commit_buffer = 0;
1986         setup_revisions(ac, av, &revs, NULL);
1987
1988         while (fgets(line, sizeof(line), stdin) != NULL) {
1989                 int len = strlen(line);
1990                 if (len && line[len - 1] == '\n')
1991                         line[--len] = 0;
1992                 if (!len)
1993                         break;
1994                 if (*line == '-') {
1995                         if (!strcmp(line, "--not")) {
1996                                 flags ^= UNINTERESTING;
1997                                 continue;
1998                         }
1999                         die("not a rev '%s'", line);
2000                 }
2001                 if (handle_revision_arg(line, &revs, flags, 1))
2002                         die("bad revision '%s'", line);
2003         }
2004
2005         if (prepare_revision_walk(&revs))
2006                 die("revision walk setup failed");
2007         mark_edges_uninteresting(revs.commits, &revs, show_edge);
2008         traverse_commit_list(&revs, show_commit, show_object);
2009
2010         if (keep_unreachable)
2011                 add_objects_in_unpacked_packs(&revs);
2012         if (unpack_unreachable)
2013                 loosen_unused_packed_objects(&revs);
2014 }
2015
2016 static int adjust_perm(const char *path, mode_t mode)
2017 {
2018         if (chmod(path, mode))
2019                 return -1;
2020         return adjust_shared_perm(path);
2021 }
2022
2023 int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2024 {
2025         int use_internal_rev_list = 0;
2026         int thin = 0;
2027         uint32_t i;
2028         const char **rp_av;
2029         int rp_ac_alloc = 64;
2030         int rp_ac;
2031
2032         rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
2033
2034         rp_av[0] = "pack-objects";
2035         rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
2036         rp_ac = 2;
2037
2038         git_config(git_pack_config, NULL);
2039         if (!pack_compression_seen && core_compression_seen)
2040                 pack_compression_level = core_compression_level;
2041
2042         progress = isatty(2);
2043         for (i = 1; i < argc; i++) {
2044                 const char *arg = argv[i];
2045
2046                 if (*arg != '-')
2047                         break;
2048
2049                 if (!strcmp("--non-empty", arg)) {
2050                         non_empty = 1;
2051                         continue;
2052                 }
2053                 if (!strcmp("--local", arg)) {
2054                         local = 1;
2055                         continue;
2056                 }
2057                 if (!strcmp("--incremental", arg)) {
2058                         incremental = 1;
2059                         continue;
2060                 }
2061                 if (!prefixcmp(arg, "--compression=")) {
2062                         char *end;
2063                         int level = strtoul(arg+14, &end, 0);
2064                         if (!arg[14] || *end)
2065                                 usage(pack_usage);
2066                         if (level == -1)
2067                                 level = Z_DEFAULT_COMPRESSION;
2068                         else if (level < 0 || level > Z_BEST_COMPRESSION)
2069                                 die("bad pack compression level %d", level);
2070                         pack_compression_level = level;
2071                         continue;
2072                 }
2073                 if (!prefixcmp(arg, "--max-pack-size=")) {
2074                         char *end;
2075                         pack_size_limit_cfg = 0;
2076                         pack_size_limit = strtoul(arg+16, &end, 0) * 1024 * 1024;
2077                         if (!arg[16] || *end)
2078                                 usage(pack_usage);
2079                         continue;
2080                 }
2081                 if (!prefixcmp(arg, "--window=")) {
2082                         char *end;
2083                         window = strtoul(arg+9, &end, 0);
2084                         if (!arg[9] || *end)
2085                                 usage(pack_usage);
2086                         continue;
2087                 }
2088                 if (!prefixcmp(arg, "--window-memory=")) {
2089                         if (!git_parse_ulong(arg+16, &window_memory_limit))
2090                                 usage(pack_usage);
2091                         continue;
2092                 }
2093                 if (!prefixcmp(arg, "--threads=")) {
2094                         char *end;
2095                         delta_search_threads = strtoul(arg+10, &end, 0);
2096                         if (!arg[10] || *end || delta_search_threads < 0)
2097                                 usage(pack_usage);
2098 #ifndef THREADED_DELTA_SEARCH
2099                         if (delta_search_threads != 1)
2100                                 warning("no threads support, "
2101                                         "ignoring %s", arg);
2102 #endif
2103                         continue;
2104                 }
2105                 if (!prefixcmp(arg, "--depth=")) {
2106                         char *end;
2107                         depth = strtoul(arg+8, &end, 0);
2108                         if (!arg[8] || *end)
2109                                 usage(pack_usage);
2110                         continue;
2111                 }
2112                 if (!strcmp("--progress", arg)) {
2113                         progress = 1;
2114                         continue;
2115                 }
2116                 if (!strcmp("--all-progress", arg)) {
2117                         progress = 2;
2118                         continue;
2119                 }
2120                 if (!strcmp("-q", arg)) {
2121                         progress = 0;
2122                         continue;
2123                 }
2124                 if (!strcmp("--no-reuse-delta", arg)) {
2125                         reuse_delta = 0;
2126                         continue;
2127                 }
2128                 if (!strcmp("--no-reuse-object", arg)) {
2129                         reuse_object = reuse_delta = 0;
2130                         continue;
2131                 }
2132                 if (!strcmp("--delta-base-offset", arg)) {
2133                         allow_ofs_delta = 1;
2134                         continue;
2135                 }
2136                 if (!strcmp("--stdout", arg)) {
2137                         pack_to_stdout = 1;
2138                         continue;
2139                 }
2140                 if (!strcmp("--revs", arg)) {
2141                         use_internal_rev_list = 1;
2142                         continue;
2143                 }
2144                 if (!strcmp("--keep-unreachable", arg)) {
2145                         keep_unreachable = 1;
2146                         continue;
2147                 }
2148                 if (!strcmp("--unpack-unreachable", arg)) {
2149                         unpack_unreachable = 1;
2150                         continue;
2151                 }
2152                 if (!strcmp("--include-tag", arg)) {
2153                         include_tag = 1;
2154                         continue;
2155                 }
2156                 if (!strcmp("--unpacked", arg) ||
2157                     !prefixcmp(arg, "--unpacked=") ||
2158                     !strcmp("--reflog", arg) ||
2159                     !strcmp("--all", arg)) {
2160                         use_internal_rev_list = 1;
2161                         if (rp_ac >= rp_ac_alloc - 1) {
2162                                 rp_ac_alloc = alloc_nr(rp_ac_alloc);
2163                                 rp_av = xrealloc(rp_av,
2164                                                  rp_ac_alloc * sizeof(*rp_av));
2165                         }
2166                         rp_av[rp_ac++] = arg;
2167                         continue;
2168                 }
2169                 if (!strcmp("--thin", arg)) {
2170                         use_internal_rev_list = 1;
2171                         thin = 1;
2172                         rp_av[1] = "--objects-edge";
2173                         continue;
2174                 }
2175                 if (!prefixcmp(arg, "--index-version=")) {
2176                         char *c;
2177                         pack_idx_default_version = strtoul(arg + 16, &c, 10);
2178                         if (pack_idx_default_version > 2)
2179                                 die("bad %s", arg);
2180                         if (*c == ',')
2181                                 pack_idx_off32_limit = strtoul(c+1, &c, 0);
2182                         if (*c || pack_idx_off32_limit & 0x80000000)
2183                                 die("bad %s", arg);
2184                         continue;
2185                 }
2186                 usage(pack_usage);
2187         }
2188
2189         /* Traditionally "pack-objects [options] base extra" failed;
2190          * we would however want to take refs parameter that would
2191          * have been given to upstream rev-list ourselves, which means
2192          * we somehow want to say what the base name is.  So the
2193          * syntax would be:
2194          *
2195          * pack-objects [options] base <refs...>
2196          *
2197          * in other words, we would treat the first non-option as the
2198          * base_name and send everything else to the internal revision
2199          * walker.
2200          */
2201
2202         if (!pack_to_stdout)
2203                 base_name = argv[i++];
2204
2205         if (pack_to_stdout != !base_name)
2206                 usage(pack_usage);
2207
2208         if (!pack_to_stdout && !pack_size_limit)
2209                 pack_size_limit = pack_size_limit_cfg;
2210
2211         if (pack_to_stdout && pack_size_limit)
2212                 die("--max-pack-size cannot be used to build a pack for transfer.");
2213
2214         if (!pack_to_stdout && thin)
2215                 die("--thin cannot be used to build an indexable pack.");
2216
2217         if (keep_unreachable && unpack_unreachable)
2218                 die("--keep-unreachable and --unpack-unreachable are incompatible.");
2219
2220 #ifdef THREADED_DELTA_SEARCH
2221         if (!delta_search_threads)      /* --threads=0 means autodetect */
2222                 delta_search_threads = online_cpus();
2223 #endif
2224
2225         prepare_packed_git();
2226
2227         if (progress)
2228                 progress_state = start_progress("Counting objects", 0);
2229         if (!use_internal_rev_list)
2230                 read_object_list_from_stdin();
2231         else {
2232                 rp_av[rp_ac] = NULL;
2233                 get_object_list(rp_ac, rp_av);
2234         }
2235         if (include_tag && nr_result)
2236                 for_each_ref(add_ref_tag, NULL);
2237         stop_progress(&progress_state);
2238
2239         if (non_empty && !nr_result)
2240                 return 0;
2241         if (nr_result)
2242                 prepare_pack(window, depth);
2243         write_pack_file();
2244         if (progress)
2245                 fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
2246                         " reused %"PRIu32" (delta %"PRIu32")\n",
2247                         written, written_delta, reused, reused_delta);
2248         return 0;
2249 }