builtin-pack-objects.con commit Lazily open pack index files on demand (d079837)
   1#include "builtin.h"
   2#include "cache.h"
   3#include "object.h"
   4#include "blob.h"
   5#include "commit.h"
   6#include "tag.h"
   7#include "tree.h"
   8#include "delta.h"
   9#include "pack.h"
  10#include "csum-file.h"
  11#include "tree-walk.h"
  12#include "diff.h"
  13#include "revision.h"
  14#include "list-objects.h"
  15#include "progress.h"
  16
  17static const char pack_usage[] = "\
  18git-pack-objects [{ -q | --progress | --all-progress }] \n\
  19        [--local] [--incremental] [--window=N] [--depth=N] \n\
  20        [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
  21        [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
  22        [--stdout | base-name] [<ref-list | <object-list]";
  23
  24struct object_entry {
  25        unsigned char sha1[20];
  26        uint32_t crc32;         /* crc of raw pack data for this object */
  27        off_t offset;           /* offset into the final pack file */
  28        unsigned long size;     /* uncompressed size */
  29        unsigned int hash;      /* name hint hash */
  30        unsigned int depth;     /* delta depth */
  31        struct packed_git *in_pack;     /* already in pack */
  32        off_t in_pack_offset;
  33        struct object_entry *delta;     /* delta base object */
  34        struct object_entry *delta_child; /* deltified objects who bases me */
  35        struct object_entry *delta_sibling; /* other deltified objects who
  36                                             * uses the same base as me
  37                                             */
  38        unsigned long delta_size;       /* delta data size (uncompressed) */
  39        enum object_type type;
  40        enum object_type in_pack_type;  /* could be delta */
  41        unsigned char in_pack_header_size;
  42        unsigned char preferred_base; /* we do not pack this, but is available
  43                                       * to be used as the base objectto delta
  44                                       * objects against.
  45                                       */
  46};
  47
  48/*
  49 * Objects we are going to pack are collected in objects array (dynamically
  50 * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  51 * in the order we see -- typically rev-list --objects order that gives us
  52 * nice "minimum seek" order.
  53 */
  54static struct object_entry *objects;
  55static uint32_t nr_objects, nr_alloc, nr_result;
  56
  57static int non_empty;
  58static int no_reuse_delta, no_reuse_object;
  59static int local;
  60static int incremental;
  61static int allow_ofs_delta;
  62static const char *pack_tmp_name, *idx_tmp_name;
  63static char tmpname[PATH_MAX];
  64static unsigned char pack_file_sha1[20];
  65static int progress = 1;
  66static int window = 10;
  67static int depth = 50;
  68static int pack_to_stdout;
  69static int num_preferred_base;
  70static struct progress progress_state;
  71static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  72static int pack_compression_seen;
  73
  74/*
  75 * The object names in objects array are hashed with this hashtable,
  76 * to help looking up the entry by object name.
  77 * This hashtable is built after all the objects are seen.
  78 */
  79static int *object_ix;
  80static int object_ix_hashsz;
  81
  82/*
  83 * Pack index for existing packs give us easy access to the offsets into
  84 * corresponding pack file where each object's data starts, but the entries
  85 * do not store the size of the compressed representation (uncompressed
  86 * size is easily available by examining the pack entry header).  It is
  87 * also rather expensive to find the sha1 for an object given its offset.
  88 *
  89 * We build a hashtable of existing packs (pack_revindex), and keep reverse
  90 * index here -- pack index file is sorted by object name mapping to offset;
  91 * this pack_revindex[].revindex array is a list of offset/index_nr pairs
  92 * ordered by offset, so if you know the offset of an object, next offset
  93 * is where its packed representation ends and the index_nr can be used to
  94 * get the object sha1 from the main index.
  95 */
  96struct revindex_entry {
  97        off_t offset;
  98        unsigned int nr;
  99};
 100struct pack_revindex {
 101        struct packed_git *p;
 102        struct revindex_entry *revindex;
 103};
 104static struct  pack_revindex *pack_revindex;
 105static int pack_revindex_hashsz;
 106
 107/*
 108 * stats
 109 */
 110static uint32_t written, written_delta;
 111static uint32_t reused, reused_delta;
 112
 113static int pack_revindex_ix(struct packed_git *p)
 114{
 115        unsigned long ui = (unsigned long)p;
 116        int i;
 117
 118        ui = ui ^ (ui >> 16); /* defeat structure alignment */
 119        i = (int)(ui % pack_revindex_hashsz);
 120        while (pack_revindex[i].p) {
 121                if (pack_revindex[i].p == p)
 122                        return i;
 123                if (++i == pack_revindex_hashsz)
 124                        i = 0;
 125        }
 126        return -1 - i;
 127}
 128
 129static void prepare_pack_ix(void)
 130{
 131        int num;
 132        struct packed_git *p;
 133        for (num = 0, p = packed_git; p; p = p->next)
 134                num++;
 135        if (!num)
 136                return;
 137        pack_revindex_hashsz = num * 11;
 138        pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 139        for (p = packed_git; p; p = p->next) {
 140                num = pack_revindex_ix(p);
 141                num = - 1 - num;
 142                pack_revindex[num].p = p;
 143        }
 144        /* revindex elements are lazily initialized */
 145}
 146
 147static int cmp_offset(const void *a_, const void *b_)
 148{
 149        const struct revindex_entry *a = a_;
 150        const struct revindex_entry *b = b_;
 151        return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
 152}
 153
 154/*
 155 * Ordered list of offsets of objects in the pack.
 156 */
 157static void prepare_pack_revindex(struct pack_revindex *rix)
 158{
 159        struct packed_git *p = rix->p;
 160        int num_ent = p->num_objects;
 161        int i;
 162        const char *index = p->index_data;
 163
 164        rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
 165        index += 4 * 256;
 166
 167        if (p->index_version > 1) {
 168                const uint32_t *off_32 =
 169                        (uint32_t *)(index + 8 + p->num_objects * (20 + 4));
 170                const uint32_t *off_64 = off_32 + p->num_objects;
 171                for (i = 0; i < num_ent; i++) {
 172                        uint32_t off = ntohl(*off_32++);
 173                        if (!(off & 0x80000000)) {
 174                                rix->revindex[i].offset = off;
 175                        } else {
 176                                rix->revindex[i].offset =
 177                                        ((uint64_t)ntohl(*off_64++)) << 32;
 178                                rix->revindex[i].offset |=
 179                                        ntohl(*off_64++);
 180                        }
 181                        rix->revindex[i].nr = i;
 182                }
 183        } else {
 184                for (i = 0; i < num_ent; i++) {
 185                        uint32_t hl = *((uint32_t *)(index + 24 * i));
 186                        rix->revindex[i].offset = ntohl(hl);
 187                        rix->revindex[i].nr = i;
 188                }
 189        }
 190
 191        /* This knows the pack format -- the 20-byte trailer
 192         * follows immediately after the last object data.
 193         */
 194        rix->revindex[num_ent].offset = p->pack_size - 20;
 195        rix->revindex[num_ent].nr = -1;
 196        qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
 197}
 198
 199static struct revindex_entry * find_packed_object(struct packed_git *p,
 200                                                  off_t ofs)
 201{
 202        int num;
 203        int lo, hi;
 204        struct pack_revindex *rix;
 205        struct revindex_entry *revindex;
 206        num = pack_revindex_ix(p);
 207        if (num < 0)
 208                die("internal error: pack revindex uninitialized");
 209        rix = &pack_revindex[num];
 210        if (!rix->revindex)
 211                prepare_pack_revindex(rix);
 212        revindex = rix->revindex;
 213        lo = 0;
 214        hi = p->num_objects + 1;
 215        do {
 216                int mi = (lo + hi) / 2;
 217                if (revindex[mi].offset == ofs) {
 218                        return revindex + mi;
 219                }
 220                else if (ofs < revindex[mi].offset)
 221                        hi = mi;
 222                else
 223                        lo = mi + 1;
 224        } while (lo < hi);
 225        die("internal error: pack revindex corrupt");
 226}
 227
 228static const unsigned char *find_packed_object_name(struct packed_git *p,
 229                                                    off_t ofs)
 230{
 231        struct revindex_entry *entry = find_packed_object(p, ofs);
 232        return nth_packed_object_sha1(p, entry->nr);
 233}
 234
 235static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 236{
 237        unsigned long othersize, delta_size;
 238        enum object_type type;
 239        void *otherbuf = read_sha1_file(entry->delta->sha1, &type, &othersize);
 240        void *delta_buf;
 241
 242        if (!otherbuf)
 243                die("unable to read %s", sha1_to_hex(entry->delta->sha1));
 244        delta_buf = diff_delta(otherbuf, othersize,
 245                               buf, size, &delta_size, 0);
 246        if (!delta_buf || delta_size != entry->delta_size)
 247                die("delta size changed");
 248        free(buf);
 249        free(otherbuf);
 250        return delta_buf;
 251}
 252
 253/*
 254 * The per-object header is a pretty dense thing, which is
 255 *  - first byte: low four bits are "size", then three bits of "type",
 256 *    and the high bit is "size continues".
 257 *  - each byte afterwards: low seven bits are size continuation,
 258 *    with the high bit being "size continues"
 259 */
 260static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 261{
 262        int n = 1;
 263        unsigned char c;
 264
 265        if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 266                die("bad type %d", type);
 267
 268        c = (type << 4) | (size & 15);
 269        size >>= 4;
 270        while (size) {
 271                *hdr++ = c | 0x80;
 272                c = size & 0x7f;
 273                size >>= 7;
 274                n++;
 275        }
 276        *hdr = c;
 277        return n;
 278}
 279
 280/*
 281 * we are going to reuse the existing object data as is.  make
 282 * sure it is not corrupt.
 283 */
 284static int check_pack_inflate(struct packed_git *p,
 285                struct pack_window **w_curs,
 286                off_t offset,
 287                off_t len,
 288                unsigned long expect)
 289{
 290        z_stream stream;
 291        unsigned char fakebuf[4096], *in;
 292        int st;
 293
 294        memset(&stream, 0, sizeof(stream));
 295        inflateInit(&stream);
 296        do {
 297                in = use_pack(p, w_curs, offset, &stream.avail_in);
 298                stream.next_in = in;
 299                stream.next_out = fakebuf;
 300                stream.avail_out = sizeof(fakebuf);
 301                st = inflate(&stream, Z_FINISH);
 302                offset += stream.next_in - in;
 303        } while (st == Z_OK || st == Z_BUF_ERROR);
 304        inflateEnd(&stream);
 305        return (st == Z_STREAM_END &&
 306                stream.total_out == expect &&
 307                stream.total_in == len) ? 0 : -1;
 308}
 309
 310static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
 311                          off_t offset, off_t len, unsigned int nr)
 312{
 313        const uint32_t *index_crc;
 314        uint32_t data_crc = crc32(0, Z_NULL, 0);
 315
 316        do {
 317                unsigned int avail;
 318                void *data = use_pack(p, w_curs, offset, &avail);
 319                if (avail > len)
 320                        avail = len;
 321                data_crc = crc32(data_crc, data, avail);
 322                offset += avail;
 323                len -= avail;
 324        } while (len);
 325
 326        index_crc = p->index_data;
 327        index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
 328
 329        return data_crc != ntohl(*index_crc);
 330}
 331
 332static void copy_pack_data(struct sha1file *f,
 333                struct packed_git *p,
 334                struct pack_window **w_curs,
 335                off_t offset,
 336                off_t len)
 337{
 338        unsigned char *in;
 339        unsigned int avail;
 340
 341        while (len) {
 342                in = use_pack(p, w_curs, offset, &avail);
 343                if (avail > len)
 344                        avail = (unsigned int)len;
 345                sha1write(f, in, avail);
 346                offset += avail;
 347                len -= avail;
 348        }
 349}
 350
 351static unsigned long write_object(struct sha1file *f,
 352                                  struct object_entry *entry)
 353{
 354        unsigned long size;
 355        enum object_type type;
 356        void *buf;
 357        unsigned char header[10];
 358        unsigned hdrlen;
 359        off_t datalen;
 360        enum object_type obj_type;
 361        int to_reuse = 0;
 362
 363        if (!pack_to_stdout)
 364                crc32_begin(f);
 365
 366        obj_type = entry->type;
 367        if (no_reuse_object)
 368                to_reuse = 0;   /* explicit */
 369        else if (!entry->in_pack)
 370                to_reuse = 0;   /* can't reuse what we don't have */
 371        else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 372                to_reuse = 1;   /* check_object() decided it for us */
 373        else if (obj_type != entry->in_pack_type)
 374                to_reuse = 0;   /* pack has delta which is unusable */
 375        else if (entry->delta)
 376                to_reuse = 0;   /* we want to pack afresh */
 377        else
 378                to_reuse = 1;   /* we have it in-pack undeltified,
 379                                 * and we do not need to deltify it.
 380                                 */
 381
 382        if (!to_reuse) {
 383                buf = read_sha1_file(entry->sha1, &type, &size);
 384                if (!buf)
 385                        die("unable to read %s", sha1_to_hex(entry->sha1));
 386                if (size != entry->size)
 387                        die("object %s size inconsistency (%lu vs %lu)",
 388                            sha1_to_hex(entry->sha1), size, entry->size);
 389                if (entry->delta) {
 390                        buf = delta_against(buf, size, entry);
 391                        size = entry->delta_size;
 392                        obj_type = (allow_ofs_delta && entry->delta->offset) ?
 393                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 394                }
 395                /*
 396                 * The object header is a byte of 'type' followed by zero or
 397                 * more bytes of length.
 398                 */
 399                hdrlen = encode_header(obj_type, size, header);
 400                sha1write(f, header, hdrlen);
 401
 402                if (obj_type == OBJ_OFS_DELTA) {
 403                        /*
 404                         * Deltas with relative base contain an additional
 405                         * encoding of the relative offset for the delta
 406                         * base from this object's position in the pack.
 407                         */
 408                        off_t ofs = entry->offset - entry->delta->offset;
 409                        unsigned pos = sizeof(header) - 1;
 410                        header[pos] = ofs & 127;
 411                        while (ofs >>= 7)
 412                                header[--pos] = 128 | (--ofs & 127);
 413                        sha1write(f, header + pos, sizeof(header) - pos);
 414                        hdrlen += sizeof(header) - pos;
 415                } else if (obj_type == OBJ_REF_DELTA) {
 416                        /*
 417                         * Deltas with a base reference contain
 418                         * an additional 20 bytes for the base sha1.
 419                         */
 420                        sha1write(f, entry->delta->sha1, 20);
 421                        hdrlen += 20;
 422                }
 423                datalen = sha1write_compressed(f, buf, size, pack_compression_level);
 424                free(buf);
 425        }
 426        else {
 427                struct packed_git *p = entry->in_pack;
 428                struct pack_window *w_curs = NULL;
 429                struct revindex_entry *revidx;
 430                off_t offset;
 431
 432                if (entry->delta) {
 433                        obj_type = (allow_ofs_delta && entry->delta->offset) ?
 434                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 435                        reused_delta++;
 436                }
 437                hdrlen = encode_header(obj_type, entry->size, header);
 438                sha1write(f, header, hdrlen);
 439                if (obj_type == OBJ_OFS_DELTA) {
 440                        off_t ofs = entry->offset - entry->delta->offset;
 441                        unsigned pos = sizeof(header) - 1;
 442                        header[pos] = ofs & 127;
 443                        while (ofs >>= 7)
 444                                header[--pos] = 128 | (--ofs & 127);
 445                        sha1write(f, header + pos, sizeof(header) - pos);
 446                        hdrlen += sizeof(header) - pos;
 447                } else if (obj_type == OBJ_REF_DELTA) {
 448                        sha1write(f, entry->delta->sha1, 20);
 449                        hdrlen += 20;
 450                }
 451
 452                offset = entry->in_pack_offset;
 453                revidx = find_packed_object(p, offset);
 454                datalen = revidx[1].offset - offset;
 455                if (!pack_to_stdout && p->index_version > 1 &&
 456                    check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
 457                        die("bad packed object CRC for %s", sha1_to_hex(entry->sha1));
 458                offset += entry->in_pack_header_size;
 459                datalen -= entry->in_pack_header_size;
 460                if (!pack_to_stdout && p->index_version == 1 &&
 461                    check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
 462                        die("corrupt packed object for %s", sha1_to_hex(entry->sha1));
 463                copy_pack_data(f, p, &w_curs, offset, datalen);
 464                unuse_pack(&w_curs);
 465                reused++;
 466        }
 467        if (entry->delta)
 468                written_delta++;
 469        written++;
 470        if (!pack_to_stdout)
 471                entry->crc32 = crc32_end(f);
 472        return hdrlen + datalen;
 473}
 474
 475static off_t write_one(struct sha1file *f,
 476                               struct object_entry *e,
 477                               off_t offset)
 478{
 479        unsigned long size;
 480
 481        /* offset is non zero if object is written already. */
 482        if (e->offset || e->preferred_base)
 483                return offset;
 484
 485        /* if we are deltified, write out base object first. */
 486        if (e->delta)
 487                offset = write_one(f, e->delta, offset);
 488
 489        e->offset = offset;
 490        size = write_object(f, e);
 491
 492        /* make sure off_t is sufficiently large not to wrap */
 493        if (offset > offset + size)
 494                die("pack too large for current definition of off_t");
 495        return offset + size;
 496}
 497
 498static int open_object_dir_tmp(const char *path)
 499{
 500    snprintf(tmpname, sizeof(tmpname), "%s/%s", get_object_directory(), path);
 501    return mkstemp(tmpname);
 502}
 503
 504static off_t write_pack_file(void)
 505{
 506        uint32_t i;
 507        struct sha1file *f;
 508        off_t offset, last_obj_offset = 0;
 509        struct pack_header hdr;
 510        int do_progress = progress;
 511
 512        if (pack_to_stdout) {
 513                f = sha1fd(1, "<stdout>");
 514                do_progress >>= 1;
 515        } else {
 516                int fd = open_object_dir_tmp("tmp_pack_XXXXXX");
 517                if (fd < 0)
 518                        die("unable to create %s: %s\n", tmpname, strerror(errno));
 519                pack_tmp_name = xstrdup(tmpname);
 520                f = sha1fd(fd, pack_tmp_name);
 521        }
 522
 523        if (do_progress)
 524                start_progress(&progress_state, "Writing %u objects...", "", nr_result);
 525
 526        hdr.hdr_signature = htonl(PACK_SIGNATURE);
 527        hdr.hdr_version = htonl(PACK_VERSION);
 528        hdr.hdr_entries = htonl(nr_result);
 529        sha1write(f, &hdr, sizeof(hdr));
 530        offset = sizeof(hdr);
 531        if (!nr_result)
 532                goto done;
 533        for (i = 0; i < nr_objects; i++) {
 534                last_obj_offset = offset;
 535                offset = write_one(f, objects + i, offset);
 536                if (do_progress)
 537                        display_progress(&progress_state, written);
 538        }
 539        if (do_progress)
 540                stop_progress(&progress_state);
 541 done:
 542        if (written != nr_result)
 543                die("wrote %u objects while expecting %u", written, nr_result);
 544        sha1close(f, pack_file_sha1, 1);
 545
 546        return last_obj_offset;
 547}
 548
 549static int sha1_sort(const void *_a, const void *_b)
 550{
 551        const struct object_entry *a = *(struct object_entry **)_a;
 552        const struct object_entry *b = *(struct object_entry **)_b;
 553        return hashcmp(a->sha1, b->sha1);
 554}
 555
 556static uint32_t index_default_version = 1;
 557static uint32_t index_off32_limit = 0x7fffffff;
 558
 559static void write_index_file(off_t last_obj_offset, unsigned char *sha1)
 560{
 561        struct sha1file *f;
 562        struct object_entry **sorted_by_sha, **list, **last;
 563        uint32_t array[256];
 564        uint32_t i, index_version;
 565        SHA_CTX ctx;
 566
 567        int fd = open_object_dir_tmp("tmp_idx_XXXXXX");
 568        if (fd < 0)
 569                die("unable to create %s: %s\n", tmpname, strerror(errno));
 570        idx_tmp_name = xstrdup(tmpname);
 571        f = sha1fd(fd, idx_tmp_name);
 572
 573        if (nr_result) {
 574                uint32_t j = 0;
 575                sorted_by_sha =
 576                        xcalloc(nr_result, sizeof(struct object_entry *));
 577                for (i = 0; i < nr_objects; i++)
 578                        if (!objects[i].preferred_base)
 579                                sorted_by_sha[j++] = objects + i;
 580                if (j != nr_result)
 581                        die("listed %u objects while expecting %u", j, nr_result);
 582                qsort(sorted_by_sha, nr_result, sizeof(*sorted_by_sha), sha1_sort);
 583                list = sorted_by_sha;
 584                last = sorted_by_sha + nr_result;
 585        } else
 586                sorted_by_sha = list = last = NULL;
 587
 588        /* if last object's offset is >= 2^31 we should use index V2 */
 589        index_version = (last_obj_offset >> 31) ? 2 : index_default_version;
 590
 591        /* index versions 2 and above need a header */
 592        if (index_version >= 2) {
 593                struct pack_idx_header hdr;
 594                hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
 595                hdr.idx_version = htonl(index_version);
 596                sha1write(f, &hdr, sizeof(hdr));
 597        }
 598
 599        /*
 600         * Write the first-level table (the list is sorted,
 601         * but we use a 256-entry lookup to be able to avoid
 602         * having to do eight extra binary search iterations).
 603         */
 604        for (i = 0; i < 256; i++) {
 605                struct object_entry **next = list;
 606                while (next < last) {
 607                        struct object_entry *entry = *next;
 608                        if (entry->sha1[0] != i)
 609                                break;
 610                        next++;
 611                }
 612                array[i] = htonl(next - sorted_by_sha);
 613                list = next;
 614        }
 615        sha1write(f, array, 256 * 4);
 616
 617        /* Compute the SHA1 hash of sorted object names. */
 618        SHA1_Init(&ctx);
 619
 620        /* Write the actual SHA1 entries. */
 621        list = sorted_by_sha;
 622        for (i = 0; i < nr_result; i++) {
 623                struct object_entry *entry = *list++;
 624                if (index_version < 2) {
 625                        uint32_t offset = htonl(entry->offset);
 626                        sha1write(f, &offset, 4);
 627                }
 628                sha1write(f, entry->sha1, 20);
 629                SHA1_Update(&ctx, entry->sha1, 20);
 630        }
 631
 632        if (index_version >= 2) {
 633                unsigned int nr_large_offset = 0;
 634
 635                /* write the crc32 table */
 636                list = sorted_by_sha;
 637                for (i = 0; i < nr_objects; i++) {
 638                        struct object_entry *entry = *list++;
 639                        uint32_t crc32_val = htonl(entry->crc32);
 640                        sha1write(f, &crc32_val, 4);
 641                }
 642
 643                /* write the 32-bit offset table */
 644                list = sorted_by_sha;
 645                for (i = 0; i < nr_objects; i++) {
 646                        struct object_entry *entry = *list++;
 647                        uint32_t offset = (entry->offset <= index_off32_limit) ?
 648                                entry->offset : (0x80000000 | nr_large_offset++);
 649                        offset = htonl(offset);
 650                        sha1write(f, &offset, 4);
 651                }
 652
 653                /* write the large offset table */
 654                list = sorted_by_sha;
 655                while (nr_large_offset) {
 656                        struct object_entry *entry = *list++;
 657                        uint64_t offset = entry->offset;
 658                        if (offset > index_off32_limit) {
 659                                uint32_t split[2];
 660                                split[0]        = htonl(offset >> 32);
 661                                split[1] = htonl(offset & 0xffffffff);
 662                                sha1write(f, split, 8);
 663                                nr_large_offset--;
 664                        }
 665                }
 666        }
 667
 668        sha1write(f, pack_file_sha1, 20);
 669        sha1close(f, NULL, 1);
 670        free(sorted_by_sha);
 671        SHA1_Final(sha1, &ctx);
 672}
 673
 674static int locate_object_entry_hash(const unsigned char *sha1)
 675{
 676        int i;
 677        unsigned int ui;
 678        memcpy(&ui, sha1, sizeof(unsigned int));
 679        i = ui % object_ix_hashsz;
 680        while (0 < object_ix[i]) {
 681                if (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
 682                        return i;
 683                if (++i == object_ix_hashsz)
 684                        i = 0;
 685        }
 686        return -1 - i;
 687}
 688
 689static struct object_entry *locate_object_entry(const unsigned char *sha1)
 690{
 691        int i;
 692
 693        if (!object_ix_hashsz)
 694                return NULL;
 695
 696        i = locate_object_entry_hash(sha1);
 697        if (0 <= i)
 698                return &objects[object_ix[i]-1];
 699        return NULL;
 700}
 701
 702static void rehash_objects(void)
 703{
 704        uint32_t i;
 705        struct object_entry *oe;
 706
 707        object_ix_hashsz = nr_objects * 3;
 708        if (object_ix_hashsz < 1024)
 709                object_ix_hashsz = 1024;
 710        object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 711        memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 712        for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 713                int ix = locate_object_entry_hash(oe->sha1);
 714                if (0 <= ix)
 715                        continue;
 716                ix = -1 - ix;
 717                object_ix[ix] = i + 1;
 718        }
 719}
 720
 721static unsigned name_hash(const char *name)
 722{
 723        unsigned char c;
 724        unsigned hash = 0;
 725
 726        /*
 727         * This effectively just creates a sortable number from the
 728         * last sixteen non-whitespace characters. Last characters
 729         * count "most", so things that end in ".c" sort together.
 730         */
 731        while ((c = *name++) != 0) {
 732                if (isspace(c))
 733                        continue;
 734                hash = (hash >> 2) + (c << 24);
 735        }
 736        return hash;
 737}
 738
 739static int add_object_entry(const unsigned char *sha1, enum object_type type,
 740                            unsigned hash, int exclude)
 741{
 742        struct object_entry *entry;
 743        struct packed_git *p, *found_pack = NULL;
 744        off_t found_offset = 0;
 745        int ix;
 746
 747        ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 748        if (ix >= 0) {
 749                if (exclude) {
 750                        entry = objects + object_ix[ix] - 1;
 751                        if (!entry->preferred_base)
 752                                nr_result--;
 753                        entry->preferred_base = 1;
 754                }
 755                return 0;
 756        }
 757
 758        for (p = packed_git; p; p = p->next) {
 759                off_t offset = find_pack_entry_one(sha1, p);
 760                if (offset) {
 761                        if (!found_pack) {
 762                                found_offset = offset;
 763                                found_pack = p;
 764                        }
 765                        if (exclude)
 766                                break;
 767                        if (incremental)
 768                                return 0;
 769                        if (local && !p->pack_local)
 770                                return 0;
 771                }
 772        }
 773
 774        if (nr_objects >= nr_alloc) {
 775                nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 776                objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 777        }
 778
 779        entry = objects + nr_objects++;
 780        memset(entry, 0, sizeof(*entry));
 781        hashcpy(entry->sha1, sha1);
 782        entry->hash = hash;
 783        if (type)
 784                entry->type = type;
 785        if (exclude)
 786                entry->preferred_base = 1;
 787        else
 788                nr_result++;
 789        if (found_pack) {
 790                entry->in_pack = found_pack;
 791                entry->in_pack_offset = found_offset;
 792        }
 793
 794        if (object_ix_hashsz * 3 <= nr_objects * 4)
 795                rehash_objects();
 796        else
 797                object_ix[-1 - ix] = nr_objects;
 798
 799        if (progress)
 800                display_progress(&progress_state, nr_objects);
 801
 802        return 1;
 803}
 804
 805struct pbase_tree_cache {
 806        unsigned char sha1[20];
 807        int ref;
 808        int temporary;
 809        void *tree_data;
 810        unsigned long tree_size;
 811};
 812
 813static struct pbase_tree_cache *(pbase_tree_cache[256]);
 814static int pbase_tree_cache_ix(const unsigned char *sha1)
 815{
 816        return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 817}
 818static int pbase_tree_cache_ix_incr(int ix)
 819{
 820        return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 821}
 822
 823static struct pbase_tree {
 824        struct pbase_tree *next;
 825        /* This is a phony "cache" entry; we are not
 826         * going to evict it nor find it through _get()
 827         * mechanism -- this is for the toplevel node that
 828         * would almost always change with any commit.
 829         */
 830        struct pbase_tree_cache pcache;
 831} *pbase_tree;
 832
 833static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 834{
 835        struct pbase_tree_cache *ent, *nent;
 836        void *data;
 837        unsigned long size;
 838        enum object_type type;
 839        int neigh;
 840        int my_ix = pbase_tree_cache_ix(sha1);
 841        int available_ix = -1;
 842
 843        /* pbase-tree-cache acts as a limited hashtable.
 844         * your object will be found at your index or within a few
 845         * slots after that slot if it is cached.
 846         */
 847        for (neigh = 0; neigh < 8; neigh++) {
 848                ent = pbase_tree_cache[my_ix];
 849                if (ent && !hashcmp(ent->sha1, sha1)) {
 850                        ent->ref++;
 851                        return ent;
 852                }
 853                else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 854                         ((0 <= available_ix) &&
 855                          (!ent && pbase_tree_cache[available_ix])))
 856                        available_ix = my_ix;
 857                if (!ent)
 858                        break;
 859                my_ix = pbase_tree_cache_ix_incr(my_ix);
 860        }
 861
 862        /* Did not find one.  Either we got a bogus request or
 863         * we need to read and perhaps cache.
 864         */
 865        data = read_sha1_file(sha1, &type, &size);
 866        if (!data)
 867                return NULL;
 868        if (type != OBJ_TREE) {
 869                free(data);
 870                return NULL;
 871        }
 872
 873        /* We need to either cache or return a throwaway copy */
 874
 875        if (available_ix < 0)
 876                ent = NULL;
 877        else {
 878                ent = pbase_tree_cache[available_ix];
 879                my_ix = available_ix;
 880        }
 881
 882        if (!ent) {
 883                nent = xmalloc(sizeof(*nent));
 884                nent->temporary = (available_ix < 0);
 885        }
 886        else {
 887                /* evict and reuse */
 888                free(ent->tree_data);
 889                nent = ent;
 890        }
 891        hashcpy(nent->sha1, sha1);
 892        nent->tree_data = data;
 893        nent->tree_size = size;
 894        nent->ref = 1;
 895        if (!nent->temporary)
 896                pbase_tree_cache[my_ix] = nent;
 897        return nent;
 898}
 899
 900static void pbase_tree_put(struct pbase_tree_cache *cache)
 901{
 902        if (!cache->temporary) {
 903                cache->ref--;
 904                return;
 905        }
 906        free(cache->tree_data);
 907        free(cache);
 908}
 909
 910static int name_cmp_len(const char *name)
 911{
 912        int i;
 913        for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 914                ;
 915        return i;
 916}
 917
 918static void add_pbase_object(struct tree_desc *tree,
 919                             const char *name,
 920                             int cmplen,
 921                             const char *fullname)
 922{
 923        struct name_entry entry;
 924        int cmp;
 925
 926        while (tree_entry(tree,&entry)) {
 927                cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
 928                      memcmp(name, entry.path, cmplen);
 929                if (cmp > 0)
 930                        continue;
 931                if (cmp < 0)
 932                        return;
 933                if (name[cmplen] != '/') {
 934                        unsigned hash = name_hash(fullname);
 935                        add_object_entry(entry.sha1,
 936                                         S_ISDIR(entry.mode) ? OBJ_TREE : OBJ_BLOB,
 937                                         hash, 1);
 938                        return;
 939                }
 940                if (S_ISDIR(entry.mode)) {
 941                        struct tree_desc sub;
 942                        struct pbase_tree_cache *tree;
 943                        const char *down = name+cmplen+1;
 944                        int downlen = name_cmp_len(down);
 945
 946                        tree = pbase_tree_get(entry.sha1);
 947                        if (!tree)
 948                                return;
 949                        init_tree_desc(&sub, tree->tree_data, tree->tree_size);
 950
 951                        add_pbase_object(&sub, down, downlen, fullname);
 952                        pbase_tree_put(tree);
 953                }
 954        }
 955}
 956
 957static unsigned *done_pbase_paths;
 958static int done_pbase_paths_num;
 959static int done_pbase_paths_alloc;
 960static int done_pbase_path_pos(unsigned hash)
 961{
 962        int lo = 0;
 963        int hi = done_pbase_paths_num;
 964        while (lo < hi) {
 965                int mi = (hi + lo) / 2;
 966                if (done_pbase_paths[mi] == hash)
 967                        return mi;
 968                if (done_pbase_paths[mi] < hash)
 969                        hi = mi;
 970                else
 971                        lo = mi + 1;
 972        }
 973        return -lo-1;
 974}
 975
 976static int check_pbase_path(unsigned hash)
 977{
 978        int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
 979        if (0 <= pos)
 980                return 1;
 981        pos = -pos - 1;
 982        if (done_pbase_paths_alloc <= done_pbase_paths_num) {
 983                done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
 984                done_pbase_paths = xrealloc(done_pbase_paths,
 985                                            done_pbase_paths_alloc *
 986                                            sizeof(unsigned));
 987        }
 988        done_pbase_paths_num++;
 989        if (pos < done_pbase_paths_num)
 990                memmove(done_pbase_paths + pos + 1,
 991                        done_pbase_paths + pos,
 992                        (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
 993        done_pbase_paths[pos] = hash;
 994        return 0;
 995}
 996
 997static void add_preferred_base_object(const char *name, unsigned hash)
 998{
 999        struct pbase_tree *it;
1000        int cmplen;
1001
1002        if (!num_preferred_base || check_pbase_path(hash))
1003                return;
1004
1005        cmplen = name_cmp_len(name);
1006        for (it = pbase_tree; it; it = it->next) {
1007                if (cmplen == 0) {
1008                        add_object_entry(it->pcache.sha1, OBJ_TREE, 0, 1);
1009                }
1010                else {
1011                        struct tree_desc tree;
1012                        init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1013                        add_pbase_object(&tree, name, cmplen, name);
1014                }
1015        }
1016}
1017
1018static void add_preferred_base(unsigned char *sha1)
1019{
1020        struct pbase_tree *it;
1021        void *data;
1022        unsigned long size;
1023        unsigned char tree_sha1[20];
1024
1025        if (window <= num_preferred_base++)
1026                return;
1027
1028        data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1029        if (!data)
1030                return;
1031
1032        for (it = pbase_tree; it; it = it->next) {
1033                if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1034                        free(data);
1035                        return;
1036                }
1037        }
1038
1039        it = xcalloc(1, sizeof(*it));
1040        it->next = pbase_tree;
1041        pbase_tree = it;
1042
1043        hashcpy(it->pcache.sha1, tree_sha1);
1044        it->pcache.tree_data = data;
1045        it->pcache.tree_size = size;
1046}
1047
1048static void check_object(struct object_entry *entry)
1049{
1050        if (entry->in_pack) {
1051                struct packed_git *p = entry->in_pack;
1052                struct pack_window *w_curs = NULL;
1053                const unsigned char *base_ref = NULL;
1054                struct object_entry *base_entry;
1055                unsigned long used, used_0;
1056                unsigned int avail;
1057                off_t ofs;
1058                unsigned char *buf, c;
1059
1060                buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1061
1062                /*
1063                 * We want in_pack_type even if we do not reuse delta
1064                 * since non-delta representations could still be reused.
1065                 */
1066                used = unpack_object_header_gently(buf, avail,
1067                                                   &entry->in_pack_type,
1068                                                   &entry->size);
1069
1070                /*
1071                 * Determine if this is a delta and if so whether we can
1072                 * reuse it or not.  Otherwise let's find out as cheaply as
1073                 * possible what the actual type and size for this object is.
1074                 */
1075                switch (entry->in_pack_type) {
1076                default:
1077                        /* Not a delta hence we've already got all we need. */
1078                        entry->type = entry->in_pack_type;
1079                        entry->in_pack_header_size = used;
1080                        unuse_pack(&w_curs);
1081                        return;
1082                case OBJ_REF_DELTA:
1083                        if (!no_reuse_delta && !entry->preferred_base)
1084                                base_ref = use_pack(p, &w_curs,
1085                                                entry->in_pack_offset + used, NULL);
1086                        entry->in_pack_header_size = used + 20;
1087                        break;
1088                case OBJ_OFS_DELTA:
1089                        buf = use_pack(p, &w_curs,
1090                                       entry->in_pack_offset + used, NULL);
1091                        used_0 = 0;
1092                        c = buf[used_0++];
1093                        ofs = c & 127;
1094                        while (c & 128) {
1095                                ofs += 1;
1096                                if (!ofs || MSB(ofs, 7))
1097                                        die("delta base offset overflow in pack for %s",
1098                                            sha1_to_hex(entry->sha1));
1099                                c = buf[used_0++];
1100                                ofs = (ofs << 7) + (c & 127);
1101                        }
1102                        if (ofs >= entry->in_pack_offset)
1103                                die("delta base offset out of bound for %s",
1104                                    sha1_to_hex(entry->sha1));
1105                        ofs = entry->in_pack_offset - ofs;
1106                        if (!no_reuse_delta && !entry->preferred_base)
1107                                base_ref = find_packed_object_name(p, ofs);
1108                        entry->in_pack_header_size = used + used_0;
1109                        break;
1110                }
1111
1112                if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1113                        /*
1114                         * If base_ref was set above that means we wish to
1115                         * reuse delta data, and we even found that base
1116                         * in the list of objects we want to pack. Goodie!
1117                         *
1118                         * Depth value does not matter - find_deltas() will
1119                         * never consider reused delta as the base object to
1120                         * deltify other objects against, in order to avoid
1121                         * circular deltas.
1122                         */
1123                        entry->type = entry->in_pack_type;
1124                        entry->delta = base_entry;
1125                        entry->delta_sibling = base_entry->delta_child;
1126                        base_entry->delta_child = entry;
1127                        unuse_pack(&w_curs);
1128                        return;
1129                }
1130
1131                if (entry->type) {
1132                        /*
1133                         * This must be a delta and we already know what the
1134                         * final object type is.  Let's extract the actual
1135                         * object size from the delta header.
1136                         */
1137                        entry->size = get_size_from_delta(p, &w_curs,
1138                                        entry->in_pack_offset + entry->in_pack_header_size);
1139                        unuse_pack(&w_curs);
1140                        return;
1141                }
1142
1143                /*
1144                 * No choice but to fall back to the recursive delta walk
1145                 * with sha1_object_info() to find about the object type
1146                 * at this point...
1147                 */
1148                unuse_pack(&w_curs);
1149        }
1150
1151        entry->type = sha1_object_info(entry->sha1, &entry->size);
1152        if (entry->type < 0)
1153                die("unable to get type of object %s",
1154                    sha1_to_hex(entry->sha1));
1155}
1156
1157static int pack_offset_sort(const void *_a, const void *_b)
1158{
1159        const struct object_entry *a = *(struct object_entry **)_a;
1160        const struct object_entry *b = *(struct object_entry **)_b;
1161
1162        /* avoid filesystem trashing with loose objects */
1163        if (!a->in_pack && !b->in_pack)
1164                return hashcmp(a->sha1, b->sha1);
1165
1166        if (a->in_pack < b->in_pack)
1167                return -1;
1168        if (a->in_pack > b->in_pack)
1169                return 1;
1170        return a->in_pack_offset < b->in_pack_offset ? -1 :
1171                        (a->in_pack_offset > b->in_pack_offset);
1172}
1173
1174static void get_object_details(void)
1175{
1176        uint32_t i;
1177        struct object_entry **sorted_by_offset;
1178
1179        sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1180        for (i = 0; i < nr_objects; i++)
1181                sorted_by_offset[i] = objects + i;
1182        qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1183
1184        prepare_pack_ix();
1185        for (i = 0; i < nr_objects; i++)
1186                check_object(sorted_by_offset[i]);
1187        free(sorted_by_offset);
1188}
1189
1190static int type_size_sort(const void *_a, const void *_b)
1191{
1192        const struct object_entry *a = *(struct object_entry **)_a;
1193        const struct object_entry *b = *(struct object_entry **)_b;
1194
1195        if (a->type < b->type)
1196                return -1;
1197        if (a->type > b->type)
1198                return 1;
1199        if (a->hash < b->hash)
1200                return -1;
1201        if (a->hash > b->hash)
1202                return 1;
1203        if (a->preferred_base < b->preferred_base)
1204                return -1;
1205        if (a->preferred_base > b->preferred_base)
1206                return 1;
1207        if (a->size < b->size)
1208                return -1;
1209        if (a->size > b->size)
1210                return 1;
1211        return a > b ? -1 : (a < b);  /* newest last */
1212}
1213
1214struct unpacked {
1215        struct object_entry *entry;
1216        void *data;
1217        struct delta_index *index;
1218};
1219
1220/*
1221 * We search for deltas _backwards_ in a list sorted by type and
1222 * by size, so that we see progressively smaller and smaller files.
1223 * That's because we prefer deltas to be from the bigger file
1224 * to the smaller - deletes are potentially cheaper, but perhaps
1225 * more importantly, the bigger file is likely the more recent
1226 * one.
1227 */
1228static int try_delta(struct unpacked *trg, struct unpacked *src,
1229                     unsigned max_depth)
1230{
1231        struct object_entry *trg_entry = trg->entry;
1232        struct object_entry *src_entry = src->entry;
1233        unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1234        enum object_type type;
1235        void *delta_buf;
1236
1237        /* Don't bother doing diffs between different types */
1238        if (trg_entry->type != src_entry->type)
1239                return -1;
1240
1241        /* We do not compute delta to *create* objects we are not
1242         * going to pack.
1243         */
1244        if (trg_entry->preferred_base)
1245                return -1;
1246
1247        /*
1248         * We do not bother to try a delta that we discarded
1249         * on an earlier try, but only when reusing delta data.
1250         */
1251        if (!no_reuse_delta && trg_entry->in_pack &&
1252            trg_entry->in_pack == src_entry->in_pack &&
1253            trg_entry->in_pack_type != OBJ_REF_DELTA &&
1254            trg_entry->in_pack_type != OBJ_OFS_DELTA)
1255                return 0;
1256
1257        /* Let's not bust the allowed depth. */
1258        if (src_entry->depth >= max_depth)
1259                return 0;
1260
1261        /* Now some size filtering heuristics. */
1262        trg_size = trg_entry->size;
1263        max_size = trg_size/2 - 20;
1264        max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1265        if (max_size == 0)
1266                return 0;
1267        if (trg_entry->delta && trg_entry->delta_size <= max_size)
1268                max_size = trg_entry->delta_size-1;
1269        src_size = src_entry->size;
1270        sizediff = src_size < trg_size ? trg_size - src_size : 0;
1271        if (sizediff >= max_size)
1272                return 0;
1273
1274        /* Load data if not already done */
1275        if (!trg->data) {
1276                trg->data = read_sha1_file(trg_entry->sha1, &type, &sz);
1277                if (sz != trg_size)
1278                        die("object %s inconsistent object length (%lu vs %lu)",
1279                            sha1_to_hex(trg_entry->sha1), sz, trg_size);
1280        }
1281        if (!src->data) {
1282                src->data = read_sha1_file(src_entry->sha1, &type, &sz);
1283                if (sz != src_size)
1284                        die("object %s inconsistent object length (%lu vs %lu)",
1285                            sha1_to_hex(src_entry->sha1), sz, src_size);
1286        }
1287        if (!src->index) {
1288                src->index = create_delta_index(src->data, src_size);
1289                if (!src->index)
1290                        die("out of memory");
1291        }
1292
1293        delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1294        if (!delta_buf)
1295                return 0;
1296
1297        trg_entry->delta = src_entry;
1298        trg_entry->delta_size = delta_size;
1299        trg_entry->depth = src_entry->depth + 1;
1300        free(delta_buf);
1301        return 1;
1302}
1303
1304static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1305{
1306        struct object_entry *child = me->delta_child;
1307        unsigned int m = n;
1308        while (child) {
1309                unsigned int c = check_delta_limit(child, n + 1);
1310                if (m < c)
1311                        m = c;
1312                child = child->delta_sibling;
1313        }
1314        return m;
1315}
1316
1317static void find_deltas(struct object_entry **list, int window, int depth)
1318{
1319        uint32_t i = nr_objects, idx = 0, processed = 0;
1320        unsigned int array_size = window * sizeof(struct unpacked);
1321        struct unpacked *array;
1322        int max_depth;
1323
1324        if (!nr_objects)
1325                return;
1326        array = xmalloc(array_size);
1327        memset(array, 0, array_size);
1328        if (progress)
1329                start_progress(&progress_state, "Deltifying %u objects...", "", nr_result);
1330
1331        do {
1332                struct object_entry *entry = list[--i];
1333                struct unpacked *n = array + idx;
1334                int j;
1335
1336                if (!entry->preferred_base)
1337                        processed++;
1338
1339                if (progress)
1340                        display_progress(&progress_state, processed);
1341
1342                if (entry->delta)
1343                        /* This happens if we decided to reuse existing
1344                         * delta from a pack.  "!no_reuse_delta &&" is implied.
1345                         */
1346                        continue;
1347
1348                if (entry->size < 50)
1349                        continue;
1350                free_delta_index(n->index);
1351                n->index = NULL;
1352                free(n->data);
1353                n->data = NULL;
1354                n->entry = entry;
1355
1356                /*
1357                 * If the current object is at pack edge, take the depth the
1358                 * objects that depend on the current object into account
1359                 * otherwise they would become too deep.
1360                 */
1361                max_depth = depth;
1362                if (entry->delta_child) {
1363                        max_depth -= check_delta_limit(entry, 0);
1364                        if (max_depth <= 0)
1365                                goto next;
1366                }
1367
1368                j = window;
1369                while (--j > 0) {
1370                        uint32_t other_idx = idx + j;
1371                        struct unpacked *m;
1372                        if (other_idx >= window)
1373                                other_idx -= window;
1374                        m = array + other_idx;
1375                        if (!m->entry)
1376                                break;
1377                        if (try_delta(n, m, max_depth) < 0)
1378                                break;
1379                }
1380
1381                /* if we made n a delta, and if n is already at max
1382                 * depth, leaving it in the window is pointless.  we
1383                 * should evict it first.
1384                 */
1385                if (entry->delta && depth <= entry->depth)
1386                        continue;
1387
1388                next:
1389                idx++;
1390                if (idx >= window)
1391                        idx = 0;
1392        } while (i > 0);
1393
1394        if (progress)
1395                stop_progress(&progress_state);
1396
1397        for (i = 0; i < window; ++i) {
1398                free_delta_index(array[i].index);
1399                free(array[i].data);
1400        }
1401        free(array);
1402}
1403
1404static void prepare_pack(int window, int depth)
1405{
1406        struct object_entry **delta_list;
1407        uint32_t i;
1408
1409        get_object_details();
1410
1411        if (!window || !depth)
1412                return;
1413
1414        delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1415        for (i = 0; i < nr_objects; i++)
1416                delta_list[i] = objects + i;
1417        qsort(delta_list, nr_objects, sizeof(*delta_list), type_size_sort);
1418        find_deltas(delta_list, window+1, depth);
1419        free(delta_list);
1420}
1421
1422static int git_pack_config(const char *k, const char *v)
1423{
1424        if(!strcmp(k, "pack.window")) {
1425                window = git_config_int(k, v);
1426                return 0;
1427        }
1428        if(!strcmp(k, "pack.depth")) {
1429                depth = git_config_int(k, v);
1430                return 0;
1431        }
1432        if (!strcmp(k, "pack.compression")) {
1433                int level = git_config_int(k, v);
1434                if (level == -1)
1435                        level = Z_DEFAULT_COMPRESSION;
1436                else if (level < 0 || level > Z_BEST_COMPRESSION)
1437                        die("bad pack compression level %d", level);
1438                pack_compression_level = level;
1439                pack_compression_seen = 1;
1440                return 0;
1441        }
1442        return git_default_config(k, v);
1443}
1444
1445static void read_object_list_from_stdin(void)
1446{
1447        char line[40 + 1 + PATH_MAX + 2];
1448        unsigned char sha1[20];
1449        unsigned hash;
1450
1451        for (;;) {
1452                if (!fgets(line, sizeof(line), stdin)) {
1453                        if (feof(stdin))
1454                                break;
1455                        if (!ferror(stdin))
1456                                die("fgets returned NULL, not EOF, not error!");
1457                        if (errno != EINTR)
1458                                die("fgets: %s", strerror(errno));
1459                        clearerr(stdin);
1460                        continue;
1461                }
1462                if (line[0] == '-') {
1463                        if (get_sha1_hex(line+1, sha1))
1464                                die("expected edge sha1, got garbage:\n %s",
1465                                    line);
1466                        add_preferred_base(sha1);
1467                        continue;
1468                }
1469                if (get_sha1_hex(line, sha1))
1470                        die("expected sha1, got garbage:\n %s", line);
1471
1472                hash = name_hash(line+41);
1473                add_preferred_base_object(line+41, hash);
1474                add_object_entry(sha1, 0, hash, 0);
1475        }
1476}
1477
1478static void show_commit(struct commit *commit)
1479{
1480        add_object_entry(commit->object.sha1, OBJ_COMMIT, 0, 0);
1481}
1482
1483static void show_object(struct object_array_entry *p)
1484{
1485        unsigned hash = name_hash(p->name);
1486        add_preferred_base_object(p->name, hash);
1487        add_object_entry(p->item->sha1, p->item->type, hash, 0);
1488}
1489
1490static void show_edge(struct commit *commit)
1491{
1492        add_preferred_base(commit->object.sha1);
1493}
1494
1495static void get_object_list(int ac, const char **av)
1496{
1497        struct rev_info revs;
1498        char line[1000];
1499        int flags = 0;
1500
1501        init_revisions(&revs, NULL);
1502        save_commit_buffer = 0;
1503        track_object_refs = 0;
1504        setup_revisions(ac, av, &revs, NULL);
1505
1506        while (fgets(line, sizeof(line), stdin) != NULL) {
1507                int len = strlen(line);
1508                if (line[len - 1] == '\n')
1509                        line[--len] = 0;
1510                if (!len)
1511                        break;
1512                if (*line == '-') {
1513                        if (!strcmp(line, "--not")) {
1514                                flags ^= UNINTERESTING;
1515                                continue;
1516                        }
1517                        die("not a rev '%s'", line);
1518                }
1519                if (handle_revision_arg(line, &revs, flags, 1))
1520                        die("bad revision '%s'", line);
1521        }
1522
1523        prepare_revision_walk(&revs);
1524        mark_edges_uninteresting(revs.commits, &revs, show_edge);
1525        traverse_commit_list(&revs, show_commit, show_object);
1526}
1527
1528static int adjust_perm(const char *path, mode_t mode)
1529{
1530        if (chmod(path, mode))
1531                return -1;
1532        return adjust_shared_perm(path);
1533}
1534
1535int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1536{
1537        int use_internal_rev_list = 0;
1538        int thin = 0;
1539        uint32_t i;
1540        off_t last_obj_offset;
1541        const char *base_name = NULL;
1542        const char **rp_av;
1543        int rp_ac_alloc = 64;
1544        int rp_ac;
1545
1546        rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1547
1548        rp_av[0] = "pack-objects";
1549        rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1550        rp_ac = 2;
1551
1552        git_config(git_pack_config);
1553        if (!pack_compression_seen && core_compression_seen)
1554                pack_compression_level = core_compression_level;
1555
1556        progress = isatty(2);
1557        for (i = 1; i < argc; i++) {
1558                const char *arg = argv[i];
1559
1560                if (*arg != '-')
1561                        break;
1562
1563                if (!strcmp("--non-empty", arg)) {
1564                        non_empty = 1;
1565                        continue;
1566                }
1567                if (!strcmp("--local", arg)) {
1568                        local = 1;
1569                        continue;
1570                }
1571                if (!strcmp("--incremental", arg)) {
1572                        incremental = 1;
1573                        continue;
1574                }
1575                if (!prefixcmp(arg, "--compression=")) {
1576                        char *end;
1577                        int level = strtoul(arg+14, &end, 0);
1578                        if (!arg[14] || *end)
1579                                usage(pack_usage);
1580                        if (level == -1)
1581                                level = Z_DEFAULT_COMPRESSION;
1582                        else if (level < 0 || level > Z_BEST_COMPRESSION)
1583                                die("bad pack compression level %d", level);
1584                        pack_compression_level = level;
1585                        continue;
1586                }
1587                if (!prefixcmp(arg, "--window=")) {
1588                        char *end;
1589                        window = strtoul(arg+9, &end, 0);
1590                        if (!arg[9] || *end)
1591                                usage(pack_usage);
1592                        continue;
1593                }
1594                if (!prefixcmp(arg, "--depth=")) {
1595                        char *end;
1596                        depth = strtoul(arg+8, &end, 0);
1597                        if (!arg[8] || *end)
1598                                usage(pack_usage);
1599                        continue;
1600                }
1601                if (!strcmp("--progress", arg)) {
1602                        progress = 1;
1603                        continue;
1604                }
1605                if (!strcmp("--all-progress", arg)) {
1606                        progress = 2;
1607                        continue;
1608                }
1609                if (!strcmp("-q", arg)) {
1610                        progress = 0;
1611                        continue;
1612                }
1613                if (!strcmp("--no-reuse-delta", arg)) {
1614                        no_reuse_delta = 1;
1615                        continue;
1616                }
1617                if (!strcmp("--no-reuse-object", arg)) {
1618                        no_reuse_object = no_reuse_delta = 1;
1619                        continue;
1620                }
1621                if (!strcmp("--delta-base-offset", arg)) {
1622                        allow_ofs_delta = 1;
1623                        continue;
1624                }
1625                if (!strcmp("--stdout", arg)) {
1626                        pack_to_stdout = 1;
1627                        continue;
1628                }
1629                if (!strcmp("--revs", arg)) {
1630                        use_internal_rev_list = 1;
1631                        continue;
1632                }
1633                if (!strcmp("--unpacked", arg) ||
1634                    !prefixcmp(arg, "--unpacked=") ||
1635                    !strcmp("--reflog", arg) ||
1636                    !strcmp("--all", arg)) {
1637                        use_internal_rev_list = 1;
1638                        if (rp_ac >= rp_ac_alloc - 1) {
1639                                rp_ac_alloc = alloc_nr(rp_ac_alloc);
1640                                rp_av = xrealloc(rp_av,
1641                                                 rp_ac_alloc * sizeof(*rp_av));
1642                        }
1643                        rp_av[rp_ac++] = arg;
1644                        continue;
1645                }
1646                if (!strcmp("--thin", arg)) {
1647                        use_internal_rev_list = 1;
1648                        thin = 1;
1649                        rp_av[1] = "--objects-edge";
1650                        continue;
1651                }
1652                if (!prefixcmp(arg, "--index-version=")) {
1653                        char *c;
1654                        index_default_version = strtoul(arg + 16, &c, 10);
1655                        if (index_default_version > 2)
1656                                die("bad %s", arg);
1657                        if (*c == ',')
1658                                index_off32_limit = strtoul(c+1, &c, 0);
1659                        if (*c || index_off32_limit & 0x80000000)
1660                                die("bad %s", arg);
1661                        continue;
1662                }
1663                usage(pack_usage);
1664        }
1665
1666        /* Traditionally "pack-objects [options] base extra" failed;
1667         * we would however want to take refs parameter that would
1668         * have been given to upstream rev-list ourselves, which means
1669         * we somehow want to say what the base name is.  So the
1670         * syntax would be:
1671         *
1672         * pack-objects [options] base <refs...>
1673         *
1674         * in other words, we would treat the first non-option as the
1675         * base_name and send everything else to the internal revision
1676         * walker.
1677         */
1678
1679        if (!pack_to_stdout)
1680                base_name = argv[i++];
1681
1682        if (pack_to_stdout != !base_name)
1683                usage(pack_usage);
1684
1685        if (!pack_to_stdout && thin)
1686                die("--thin cannot be used to build an indexable pack.");
1687
1688        prepare_packed_git();
1689
1690        if (progress)
1691                start_progress(&progress_state, "Generating pack...",
1692                               "Counting objects: ", 0);
1693        if (!use_internal_rev_list)
1694                read_object_list_from_stdin();
1695        else {
1696                rp_av[rp_ac] = NULL;
1697                get_object_list(rp_ac, rp_av);
1698        }
1699        if (progress) {
1700                stop_progress(&progress_state);
1701                fprintf(stderr, "Done counting %u objects.\n", nr_objects);
1702        }
1703
1704        if (non_empty && !nr_result)
1705                return 0;
1706        if (progress && (nr_objects != nr_result))
1707                fprintf(stderr, "Result has %u objects.\n", nr_result);
1708        if (nr_result)
1709                prepare_pack(window, depth);
1710        last_obj_offset = write_pack_file();
1711        if (!pack_to_stdout) {
1712                unsigned char object_list_sha1[20];
1713                mode_t mode = umask(0);
1714
1715                umask(mode);
1716                mode = 0444 & ~mode;
1717
1718                write_index_file(last_obj_offset, object_list_sha1);
1719                snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
1720                         base_name, sha1_to_hex(object_list_sha1));
1721                if (adjust_perm(pack_tmp_name, mode))
1722                        die("unable to make temporary pack file readable: %s",
1723                            strerror(errno));
1724                if (rename(pack_tmp_name, tmpname))
1725                        die("unable to rename temporary pack file: %s",
1726                            strerror(errno));
1727                snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
1728                         base_name, sha1_to_hex(object_list_sha1));
1729                if (adjust_perm(idx_tmp_name, mode))
1730                        die("unable to make temporary index file readable: %s",
1731                            strerror(errno));
1732                if (rename(idx_tmp_name, tmpname))
1733                        die("unable to rename temporary index file: %s",
1734                            strerror(errno));
1735                puts(sha1_to_hex(object_list_sha1));
1736        }
1737        if (progress)
1738                fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
1739                        written, written_delta, reused, reused_delta);
1740        return 0;
1741}