builtin-pack-objects.con commit Merge branch 'master' of git://git.kernel.org/pub/scm/gitk/gitk (fe5e7f3)
   1#include "builtin.h"
   2#include "cache.h"
   3#include "attr.h"
   4#include "object.h"
   5#include "blob.h"
   6#include "commit.h"
   7#include "tag.h"
   8#include "tree.h"
   9#include "delta.h"
  10#include "pack.h"
  11#include "csum-file.h"
  12#include "tree-walk.h"
  13#include "diff.h"
  14#include "revision.h"
  15#include "list-objects.h"
  16#include "progress.h"
  17
  18static const char pack_usage[] = "\
  19git-pack-objects [{ -q | --progress | --all-progress }] [--max-pack-size=N] \n\
  20        [--local] [--incremental] [--window=N] [--depth=N] \n\
  21        [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
  22        [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
  23        [--stdout | base-name] [<ref-list | <object-list]";
  24
  25struct object_entry {
  26        struct pack_idx_entry idx;
  27        unsigned long size;     /* uncompressed size */
  28
  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        void *delta_data;       /* cached delta (uncompressed) */
  39        unsigned long delta_size;       /* delta data size (uncompressed) */
  40        enum object_type type;
  41        enum object_type in_pack_type;  /* could be delta */
  42        unsigned char in_pack_header_size;
  43        unsigned char preferred_base; /* we do not pack this, but is available
  44                                       * to be used as the base object to delta
  45                                       * objects against.
  46                                       */
  47        unsigned char no_try_delta;
  48};
  49
  50/*
  51 * Objects we are going to pack are collected in objects array (dynamically
  52 * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  53 * in the order we see -- typically rev-list --objects order that gives us
  54 * nice "minimum seek" order.
  55 */
  56static struct object_entry *objects;
  57static struct object_entry **written_list;
  58static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  59
  60static int non_empty;
  61static int no_reuse_delta, no_reuse_object;
  62static int local;
  63static int incremental;
  64static int allow_ofs_delta;
  65static const char *pack_tmp_name, *idx_tmp_name;
  66static char tmpname[PATH_MAX];
  67static const char *base_name;
  68static int progress = 1;
  69static int window = 10;
  70static uint32_t pack_size_limit;
  71static int depth = 50;
  72static int pack_to_stdout;
  73static int num_preferred_base;
  74static struct progress progress_state;
  75static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  76static int pack_compression_seen;
  77
  78static unsigned long delta_cache_size = 0;
  79static unsigned long max_delta_cache_size = 0;
  80static unsigned long cache_max_small_delta_size = 1000;
  81
  82/*
  83 * The object names in objects array are hashed with this hashtable,
  84 * to help looking up the entry by object name.
  85 * This hashtable is built after all the objects are seen.
  86 */
  87static int *object_ix;
  88static int object_ix_hashsz;
  89
  90/*
  91 * Pack index for existing packs give us easy access to the offsets into
  92 * corresponding pack file where each object's data starts, but the entries
  93 * do not store the size of the compressed representation (uncompressed
  94 * size is easily available by examining the pack entry header).  It is
  95 * also rather expensive to find the sha1 for an object given its offset.
  96 *
  97 * We build a hashtable of existing packs (pack_revindex), and keep reverse
  98 * index here -- pack index file is sorted by object name mapping to offset;
  99 * this pack_revindex[].revindex array is a list of offset/index_nr pairs
 100 * ordered by offset, so if you know the offset of an object, next offset
 101 * is where its packed representation ends and the index_nr can be used to
 102 * get the object sha1 from the main index.
 103 */
 104struct revindex_entry {
 105        off_t offset;
 106        unsigned int nr;
 107};
 108struct pack_revindex {
 109        struct packed_git *p;
 110        struct revindex_entry *revindex;
 111};
 112static struct  pack_revindex *pack_revindex;
 113static int pack_revindex_hashsz;
 114
 115/*
 116 * stats
 117 */
 118static uint32_t written, written_delta;
 119static uint32_t reused, reused_delta;
 120
 121static int pack_revindex_ix(struct packed_git *p)
 122{
 123        unsigned long ui = (unsigned long)p;
 124        int i;
 125
 126        ui = ui ^ (ui >> 16); /* defeat structure alignment */
 127        i = (int)(ui % pack_revindex_hashsz);
 128        while (pack_revindex[i].p) {
 129                if (pack_revindex[i].p == p)
 130                        return i;
 131                if (++i == pack_revindex_hashsz)
 132                        i = 0;
 133        }
 134        return -1 - i;
 135}
 136
 137static void prepare_pack_ix(void)
 138{
 139        int num;
 140        struct packed_git *p;
 141        for (num = 0, p = packed_git; p; p = p->next)
 142                num++;
 143        if (!num)
 144                return;
 145        pack_revindex_hashsz = num * 11;
 146        pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz);
 147        for (p = packed_git; p; p = p->next) {
 148                num = pack_revindex_ix(p);
 149                num = - 1 - num;
 150                pack_revindex[num].p = p;
 151        }
 152        /* revindex elements are lazily initialized */
 153}
 154
 155static int cmp_offset(const void *a_, const void *b_)
 156{
 157        const struct revindex_entry *a = a_;
 158        const struct revindex_entry *b = b_;
 159        return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
 160}
 161
 162/*
 163 * Ordered list of offsets of objects in the pack.
 164 */
 165static void prepare_pack_revindex(struct pack_revindex *rix)
 166{
 167        struct packed_git *p = rix->p;
 168        int num_ent = p->num_objects;
 169        int i;
 170        const char *index = p->index_data;
 171
 172        rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
 173        index += 4 * 256;
 174
 175        if (p->index_version > 1) {
 176                const uint32_t *off_32 =
 177                        (uint32_t *)(index + 8 + p->num_objects * (20 + 4));
 178                const uint32_t *off_64 = off_32 + p->num_objects;
 179                for (i = 0; i < num_ent; i++) {
 180                        uint32_t off = ntohl(*off_32++);
 181                        if (!(off & 0x80000000)) {
 182                                rix->revindex[i].offset = off;
 183                        } else {
 184                                rix->revindex[i].offset =
 185                                        ((uint64_t)ntohl(*off_64++)) << 32;
 186                                rix->revindex[i].offset |=
 187                                        ntohl(*off_64++);
 188                        }
 189                        rix->revindex[i].nr = i;
 190                }
 191        } else {
 192                for (i = 0; i < num_ent; i++) {
 193                        uint32_t hl = *((uint32_t *)(index + 24 * i));
 194                        rix->revindex[i].offset = ntohl(hl);
 195                        rix->revindex[i].nr = i;
 196                }
 197        }
 198
 199        /* This knows the pack format -- the 20-byte trailer
 200         * follows immediately after the last object data.
 201         */
 202        rix->revindex[num_ent].offset = p->pack_size - 20;
 203        rix->revindex[num_ent].nr = -1;
 204        qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
 205}
 206
 207static struct revindex_entry * find_packed_object(struct packed_git *p,
 208                                                  off_t ofs)
 209{
 210        int num;
 211        int lo, hi;
 212        struct pack_revindex *rix;
 213        struct revindex_entry *revindex;
 214        num = pack_revindex_ix(p);
 215        if (num < 0)
 216                die("internal error: pack revindex uninitialized");
 217        rix = &pack_revindex[num];
 218        if (!rix->revindex)
 219                prepare_pack_revindex(rix);
 220        revindex = rix->revindex;
 221        lo = 0;
 222        hi = p->num_objects + 1;
 223        do {
 224                int mi = (lo + hi) / 2;
 225                if (revindex[mi].offset == ofs) {
 226                        return revindex + mi;
 227                }
 228                else if (ofs < revindex[mi].offset)
 229                        hi = mi;
 230                else
 231                        lo = mi + 1;
 232        } while (lo < hi);
 233        die("internal error: pack revindex corrupt");
 234}
 235
 236static const unsigned char *find_packed_object_name(struct packed_git *p,
 237                                                    off_t ofs)
 238{
 239        struct revindex_entry *entry = find_packed_object(p, ofs);
 240        return nth_packed_object_sha1(p, entry->nr);
 241}
 242
 243static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
 244{
 245        unsigned long othersize, delta_size;
 246        enum object_type type;
 247        void *otherbuf = read_sha1_file(entry->delta->idx.sha1, &type, &othersize);
 248        void *delta_buf;
 249
 250        if (!otherbuf)
 251                die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 252        delta_buf = diff_delta(otherbuf, othersize,
 253                               buf, size, &delta_size, 0);
 254        if (!delta_buf || delta_size != entry->delta_size)
 255                die("delta size changed");
 256        free(buf);
 257        free(otherbuf);
 258        return delta_buf;
 259}
 260
 261/*
 262 * The per-object header is a pretty dense thing, which is
 263 *  - first byte: low four bits are "size", then three bits of "type",
 264 *    and the high bit is "size continues".
 265 *  - each byte afterwards: low seven bits are size continuation,
 266 *    with the high bit being "size continues"
 267 */
 268static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr)
 269{
 270        int n = 1;
 271        unsigned char c;
 272
 273        if (type < OBJ_COMMIT || type > OBJ_REF_DELTA)
 274                die("bad type %d", type);
 275
 276        c = (type << 4) | (size & 15);
 277        size >>= 4;
 278        while (size) {
 279                *hdr++ = c | 0x80;
 280                c = size & 0x7f;
 281                size >>= 7;
 282                n++;
 283        }
 284        *hdr = c;
 285        return n;
 286}
 287
 288/*
 289 * we are going to reuse the existing object data as is.  make
 290 * sure it is not corrupt.
 291 */
 292static int check_pack_inflate(struct packed_git *p,
 293                struct pack_window **w_curs,
 294                off_t offset,
 295                off_t len,
 296                unsigned long expect)
 297{
 298        z_stream stream;
 299        unsigned char fakebuf[4096], *in;
 300        int st;
 301
 302        memset(&stream, 0, sizeof(stream));
 303        inflateInit(&stream);
 304        do {
 305                in = use_pack(p, w_curs, offset, &stream.avail_in);
 306                stream.next_in = in;
 307                stream.next_out = fakebuf;
 308                stream.avail_out = sizeof(fakebuf);
 309                st = inflate(&stream, Z_FINISH);
 310                offset += stream.next_in - in;
 311        } while (st == Z_OK || st == Z_BUF_ERROR);
 312        inflateEnd(&stream);
 313        return (st == Z_STREAM_END &&
 314                stream.total_out == expect &&
 315                stream.total_in == len) ? 0 : -1;
 316}
 317
 318static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
 319                          off_t offset, off_t len, unsigned int nr)
 320{
 321        const uint32_t *index_crc;
 322        uint32_t data_crc = crc32(0, Z_NULL, 0);
 323
 324        do {
 325                unsigned int avail;
 326                void *data = use_pack(p, w_curs, offset, &avail);
 327                if (avail > len)
 328                        avail = len;
 329                data_crc = crc32(data_crc, data, avail);
 330                offset += avail;
 331                len -= avail;
 332        } while (len);
 333
 334        index_crc = p->index_data;
 335        index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
 336
 337        return data_crc != ntohl(*index_crc);
 338}
 339
 340static void copy_pack_data(struct sha1file *f,
 341                struct packed_git *p,
 342                struct pack_window **w_curs,
 343                off_t offset,
 344                off_t len)
 345{
 346        unsigned char *in;
 347        unsigned int avail;
 348
 349        while (len) {
 350                in = use_pack(p, w_curs, offset, &avail);
 351                if (avail > len)
 352                        avail = (unsigned int)len;
 353                sha1write(f, in, avail);
 354                offset += avail;
 355                len -= avail;
 356        }
 357}
 358
 359static unsigned long write_object(struct sha1file *f,
 360                                  struct object_entry *entry,
 361                                  off_t write_offset)
 362{
 363        unsigned long size;
 364        enum object_type type;
 365        void *buf;
 366        unsigned char header[10];
 367        unsigned char dheader[10];
 368        unsigned hdrlen;
 369        off_t datalen;
 370        enum object_type obj_type;
 371        int to_reuse = 0;
 372        /* write limit if limited packsize and not first object */
 373        unsigned long limit = pack_size_limit && nr_written ?
 374                                pack_size_limit - write_offset : 0;
 375                                /* no if no delta */
 376        int usable_delta =      !entry->delta ? 0 :
 377                                /* yes if unlimited packfile */
 378                                !pack_size_limit ? 1 :
 379                                /* no if base written to previous pack */
 380                                entry->delta->idx.offset == (off_t)-1 ? 0 :
 381                                /* otherwise double-check written to this
 382                                 * pack,  like we do below
 383                                 */
 384                                entry->delta->idx.offset ? 1 : 0;
 385
 386        if (!pack_to_stdout)
 387                crc32_begin(f);
 388
 389        obj_type = entry->type;
 390        if (no_reuse_object)
 391                to_reuse = 0;   /* explicit */
 392        else if (!entry->in_pack)
 393                to_reuse = 0;   /* can't reuse what we don't have */
 394        else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA)
 395                                /* check_object() decided it for us ... */
 396                to_reuse = usable_delta;
 397                                /* ... but pack split may override that */
 398        else if (obj_type != entry->in_pack_type)
 399                to_reuse = 0;   /* pack has delta which is unusable */
 400        else if (entry->delta)
 401                to_reuse = 0;   /* we want to pack afresh */
 402        else
 403                to_reuse = 1;   /* we have it in-pack undeltified,
 404                                 * and we do not need to deltify it.
 405                                 */
 406
 407        if (!to_reuse) {
 408                z_stream stream;
 409                unsigned long maxsize;
 410                void *out;
 411                if (!usable_delta) {
 412                        buf = read_sha1_file(entry->idx.sha1, &obj_type, &size);
 413                        if (!buf)
 414                                die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 415                } else if (entry->delta_data) {
 416                        size = entry->delta_size;
 417                        buf = entry->delta_data;
 418                        entry->delta_data = NULL;
 419                        obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 420                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 421                } else {
 422                        buf = read_sha1_file(entry->idx.sha1, &type, &size);
 423                        if (!buf)
 424                                die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 425                        buf = delta_against(buf, size, entry);
 426                        size = entry->delta_size;
 427                        obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 428                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 429                }
 430                /* compress the data to store and put compressed length in datalen */
 431                memset(&stream, 0, sizeof(stream));
 432                deflateInit(&stream, pack_compression_level);
 433                maxsize = deflateBound(&stream, size);
 434                out = xmalloc(maxsize);
 435                /* Compress it */
 436                stream.next_in = buf;
 437                stream.avail_in = size;
 438                stream.next_out = out;
 439                stream.avail_out = maxsize;
 440                while (deflate(&stream, Z_FINISH) == Z_OK)
 441                        /* nothing */;
 442                deflateEnd(&stream);
 443                datalen = stream.total_out;
 444                deflateEnd(&stream);
 445                /*
 446                 * The object header is a byte of 'type' followed by zero or
 447                 * more bytes of length.
 448                 */
 449                hdrlen = encode_header(obj_type, size, header);
 450
 451                if (obj_type == OBJ_OFS_DELTA) {
 452                        /*
 453                         * Deltas with relative base contain an additional
 454                         * encoding of the relative offset for the delta
 455                         * base from this object's position in the pack.
 456                         */
 457                        off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 458                        unsigned pos = sizeof(dheader) - 1;
 459                        dheader[pos] = ofs & 127;
 460                        while (ofs >>= 7)
 461                                dheader[--pos] = 128 | (--ofs & 127);
 462                        if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 463                                free(out);
 464                                free(buf);
 465                                return 0;
 466                        }
 467                        sha1write(f, header, hdrlen);
 468                        sha1write(f, dheader + pos, sizeof(dheader) - pos);
 469                        hdrlen += sizeof(dheader) - pos;
 470                } else if (obj_type == OBJ_REF_DELTA) {
 471                        /*
 472                         * Deltas with a base reference contain
 473                         * an additional 20 bytes for the base sha1.
 474                         */
 475                        if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 476                                free(out);
 477                                free(buf);
 478                                return 0;
 479                        }
 480                        sha1write(f, header, hdrlen);
 481                        sha1write(f, entry->delta->idx.sha1, 20);
 482                        hdrlen += 20;
 483                } else {
 484                        if (limit && hdrlen + datalen + 20 >= limit) {
 485                                free(out);
 486                                free(buf);
 487                                return 0;
 488                        }
 489                        sha1write(f, header, hdrlen);
 490                }
 491                sha1write(f, out, datalen);
 492                free(out);
 493                free(buf);
 494        }
 495        else {
 496                struct packed_git *p = entry->in_pack;
 497                struct pack_window *w_curs = NULL;
 498                struct revindex_entry *revidx;
 499                off_t offset;
 500
 501                if (entry->delta) {
 502                        obj_type = (allow_ofs_delta && entry->delta->idx.offset) ?
 503                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 504                        reused_delta++;
 505                }
 506                hdrlen = encode_header(obj_type, entry->size, header);
 507                offset = entry->in_pack_offset;
 508                revidx = find_packed_object(p, offset);
 509                datalen = revidx[1].offset - offset;
 510                if (!pack_to_stdout && p->index_version > 1 &&
 511                    check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
 512                        die("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 513                offset += entry->in_pack_header_size;
 514                datalen -= entry->in_pack_header_size;
 515                if (obj_type == OBJ_OFS_DELTA) {
 516                        off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 517                        unsigned pos = sizeof(dheader) - 1;
 518                        dheader[pos] = ofs & 127;
 519                        while (ofs >>= 7)
 520                                dheader[--pos] = 128 | (--ofs & 127);
 521                        if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit)
 522                                return 0;
 523                        sha1write(f, header, hdrlen);
 524                        sha1write(f, dheader + pos, sizeof(dheader) - pos);
 525                        hdrlen += sizeof(dheader) - pos;
 526                } else if (obj_type == OBJ_REF_DELTA) {
 527                        if (limit && hdrlen + 20 + datalen + 20 >= limit)
 528                                return 0;
 529                        sha1write(f, header, hdrlen);
 530                        sha1write(f, entry->delta->idx.sha1, 20);
 531                        hdrlen += 20;
 532                } else {
 533                        if (limit && hdrlen + datalen + 20 >= limit)
 534                                return 0;
 535                        sha1write(f, header, hdrlen);
 536                }
 537
 538                if (!pack_to_stdout && p->index_version == 1 &&
 539                    check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
 540                        die("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 541                copy_pack_data(f, p, &w_curs, offset, datalen);
 542                unuse_pack(&w_curs);
 543                reused++;
 544        }
 545        if (usable_delta)
 546                written_delta++;
 547        written++;
 548        if (!pack_to_stdout)
 549                entry->idx.crc32 = crc32_end(f);
 550        return hdrlen + datalen;
 551}
 552
 553static off_t write_one(struct sha1file *f,
 554                               struct object_entry *e,
 555                               off_t offset)
 556{
 557        unsigned long size;
 558
 559        /* offset is non zero if object is written already. */
 560        if (e->idx.offset || e->preferred_base)
 561                return offset;
 562
 563        /* if we are deltified, write out base object first. */
 564        if (e->delta) {
 565                offset = write_one(f, e->delta, offset);
 566                if (!offset)
 567                        return 0;
 568        }
 569
 570        e->idx.offset = offset;
 571        size = write_object(f, e, offset);
 572        if (!size) {
 573                e->idx.offset = 0;
 574                return 0;
 575        }
 576        written_list[nr_written++] = e;
 577
 578        /* make sure off_t is sufficiently large not to wrap */
 579        if (offset > offset + size)
 580                die("pack too large for current definition of off_t");
 581        return offset + size;
 582}
 583
 584static int open_object_dir_tmp(const char *path)
 585{
 586    snprintf(tmpname, sizeof(tmpname), "%s/%s", get_object_directory(), path);
 587    return mkstemp(tmpname);
 588}
 589
 590/* forward declaration for write_pack_file */
 591static int adjust_perm(const char *path, mode_t mode);
 592
 593static void write_pack_file(void)
 594{
 595        uint32_t i = 0, j;
 596        struct sha1file *f;
 597        off_t offset, offset_one, last_obj_offset = 0;
 598        struct pack_header hdr;
 599        int do_progress = progress >> pack_to_stdout;
 600        uint32_t nr_remaining = nr_result;
 601
 602        if (do_progress)
 603                start_progress(&progress_state, "Writing %u objects...", "", nr_result);
 604        written_list = xmalloc(nr_objects * sizeof(struct object_entry *));
 605
 606        do {
 607                unsigned char sha1[20];
 608
 609                if (pack_to_stdout) {
 610                        f = sha1fd(1, "<stdout>");
 611                } else {
 612                        int fd = open_object_dir_tmp("tmp_pack_XXXXXX");
 613                        if (fd < 0)
 614                                die("unable to create %s: %s\n", tmpname, strerror(errno));
 615                        pack_tmp_name = xstrdup(tmpname);
 616                        f = sha1fd(fd, pack_tmp_name);
 617                }
 618
 619                hdr.hdr_signature = htonl(PACK_SIGNATURE);
 620                hdr.hdr_version = htonl(PACK_VERSION);
 621                hdr.hdr_entries = htonl(nr_remaining);
 622                sha1write(f, &hdr, sizeof(hdr));
 623                offset = sizeof(hdr);
 624                nr_written = 0;
 625                for (; i < nr_objects; i++) {
 626                        last_obj_offset = offset;
 627                        offset_one = write_one(f, objects + i, offset);
 628                        if (!offset_one)
 629                                break;
 630                        offset = offset_one;
 631                        if (do_progress)
 632                                display_progress(&progress_state, written);
 633                }
 634
 635                /*
 636                 * Did we write the wrong # entries in the header?
 637                 * If so, rewrite it like in fast-import
 638                 */
 639                if (pack_to_stdout || nr_written == nr_remaining) {
 640                        sha1close(f, sha1, 1);
 641                } else {
 642                        sha1close(f, sha1, 0);
 643                        fixup_pack_header_footer(f->fd, sha1, pack_tmp_name, nr_written);
 644                        close(f->fd);
 645                }
 646
 647                if (!pack_to_stdout) {
 648                        mode_t mode = umask(0);
 649
 650                        umask(mode);
 651                        mode = 0444 & ~mode;
 652
 653                        idx_tmp_name = write_idx_file(NULL,
 654                                (struct pack_idx_entry **) written_list, nr_written, sha1);
 655                        snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
 656                                 base_name, sha1_to_hex(sha1));
 657                        if (adjust_perm(pack_tmp_name, mode))
 658                                die("unable to make temporary pack file readable: %s",
 659                                    strerror(errno));
 660                        if (rename(pack_tmp_name, tmpname))
 661                                die("unable to rename temporary pack file: %s",
 662                                    strerror(errno));
 663                        snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
 664                                 base_name, sha1_to_hex(sha1));
 665                        if (adjust_perm(idx_tmp_name, mode))
 666                                die("unable to make temporary index file readable: %s",
 667                                    strerror(errno));
 668                        if (rename(idx_tmp_name, tmpname))
 669                                die("unable to rename temporary index file: %s",
 670                                    strerror(errno));
 671                        puts(sha1_to_hex(sha1));
 672                }
 673
 674                /* mark written objects as written to previous pack */
 675                for (j = 0; j < nr_written; j++) {
 676                        written_list[j]->idx.offset = (off_t)-1;
 677                }
 678                nr_remaining -= nr_written;
 679        } while (nr_remaining && i < nr_objects);
 680
 681        free(written_list);
 682        if (do_progress)
 683                stop_progress(&progress_state);
 684        if (written != nr_result)
 685                die("wrote %u objects while expecting %u", written, nr_result);
 686        /*
 687         * We have scanned through [0 ... i).  Since we have written
 688         * the correct number of objects,  the remaining [i ... nr_objects)
 689         * items must be either already written (due to out-of-order delta base)
 690         * or a preferred base.  Count those which are neither and complain if any.
 691         */
 692        for (j = 0; i < nr_objects; i++) {
 693                struct object_entry *e = objects + i;
 694                j += !e->idx.offset && !e->preferred_base;
 695        }
 696        if (j)
 697                die("wrote %u objects as expected but %u unwritten", written, j);
 698}
 699
 700static int locate_object_entry_hash(const unsigned char *sha1)
 701{
 702        int i;
 703        unsigned int ui;
 704        memcpy(&ui, sha1, sizeof(unsigned int));
 705        i = ui % object_ix_hashsz;
 706        while (0 < object_ix[i]) {
 707                if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 708                        return i;
 709                if (++i == object_ix_hashsz)
 710                        i = 0;
 711        }
 712        return -1 - i;
 713}
 714
 715static struct object_entry *locate_object_entry(const unsigned char *sha1)
 716{
 717        int i;
 718
 719        if (!object_ix_hashsz)
 720                return NULL;
 721
 722        i = locate_object_entry_hash(sha1);
 723        if (0 <= i)
 724                return &objects[object_ix[i]-1];
 725        return NULL;
 726}
 727
 728static void rehash_objects(void)
 729{
 730        uint32_t i;
 731        struct object_entry *oe;
 732
 733        object_ix_hashsz = nr_objects * 3;
 734        if (object_ix_hashsz < 1024)
 735                object_ix_hashsz = 1024;
 736        object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 737        memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 738        for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 739                int ix = locate_object_entry_hash(oe->idx.sha1);
 740                if (0 <= ix)
 741                        continue;
 742                ix = -1 - ix;
 743                object_ix[ix] = i + 1;
 744        }
 745}
 746
 747static unsigned name_hash(const char *name)
 748{
 749        unsigned char c;
 750        unsigned hash = 0;
 751
 752        if (!name)
 753                return 0;
 754
 755        /*
 756         * This effectively just creates a sortable number from the
 757         * last sixteen non-whitespace characters. Last characters
 758         * count "most", so things that end in ".c" sort together.
 759         */
 760        while ((c = *name++) != 0) {
 761                if (isspace(c))
 762                        continue;
 763                hash = (hash >> 2) + (c << 24);
 764        }
 765        return hash;
 766}
 767
 768static void setup_delta_attr_check(struct git_attr_check *check)
 769{
 770        static struct git_attr *attr_delta;
 771
 772        if (!attr_delta)
 773                attr_delta = git_attr("delta", 5);
 774
 775        check[0].attr = attr_delta;
 776}
 777
 778static int no_try_delta(const char *path)
 779{
 780        struct git_attr_check check[1];
 781
 782        setup_delta_attr_check(check);
 783        if (git_checkattr(path, ARRAY_SIZE(check), check))
 784                return 0;
 785        if (ATTR_FALSE(check->value))
 786                return 1;
 787        return 0;
 788}
 789
 790static int add_object_entry(const unsigned char *sha1, enum object_type type,
 791                            const char *name, int exclude)
 792{
 793        struct object_entry *entry;
 794        struct packed_git *p, *found_pack = NULL;
 795        off_t found_offset = 0;
 796        int ix;
 797        unsigned hash = name_hash(name);
 798
 799        ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 800        if (ix >= 0) {
 801                if (exclude) {
 802                        entry = objects + object_ix[ix] - 1;
 803                        if (!entry->preferred_base)
 804                                nr_result--;
 805                        entry->preferred_base = 1;
 806                }
 807                return 0;
 808        }
 809
 810        for (p = packed_git; p; p = p->next) {
 811                off_t offset = find_pack_entry_one(sha1, p);
 812                if (offset) {
 813                        if (!found_pack) {
 814                                found_offset = offset;
 815                                found_pack = p;
 816                        }
 817                        if (exclude)
 818                                break;
 819                        if (incremental)
 820                                return 0;
 821                        if (local && !p->pack_local)
 822                                return 0;
 823                }
 824        }
 825
 826        if (nr_objects >= nr_alloc) {
 827                nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 828                objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 829        }
 830
 831        entry = objects + nr_objects++;
 832        memset(entry, 0, sizeof(*entry));
 833        hashcpy(entry->idx.sha1, sha1);
 834        entry->hash = hash;
 835        if (type)
 836                entry->type = type;
 837        if (exclude)
 838                entry->preferred_base = 1;
 839        else
 840                nr_result++;
 841        if (found_pack) {
 842                entry->in_pack = found_pack;
 843                entry->in_pack_offset = found_offset;
 844        }
 845
 846        if (object_ix_hashsz * 3 <= nr_objects * 4)
 847                rehash_objects();
 848        else
 849                object_ix[-1 - ix] = nr_objects;
 850
 851        if (progress)
 852                display_progress(&progress_state, nr_objects);
 853
 854        if (name && no_try_delta(name))
 855                entry->no_try_delta = 1;
 856
 857        return 1;
 858}
 859
 860struct pbase_tree_cache {
 861        unsigned char sha1[20];
 862        int ref;
 863        int temporary;
 864        void *tree_data;
 865        unsigned long tree_size;
 866};
 867
 868static struct pbase_tree_cache *(pbase_tree_cache[256]);
 869static int pbase_tree_cache_ix(const unsigned char *sha1)
 870{
 871        return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 872}
 873static int pbase_tree_cache_ix_incr(int ix)
 874{
 875        return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 876}
 877
 878static struct pbase_tree {
 879        struct pbase_tree *next;
 880        /* This is a phony "cache" entry; we are not
 881         * going to evict it nor find it through _get()
 882         * mechanism -- this is for the toplevel node that
 883         * would almost always change with any commit.
 884         */
 885        struct pbase_tree_cache pcache;
 886} *pbase_tree;
 887
 888static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 889{
 890        struct pbase_tree_cache *ent, *nent;
 891        void *data;
 892        unsigned long size;
 893        enum object_type type;
 894        int neigh;
 895        int my_ix = pbase_tree_cache_ix(sha1);
 896        int available_ix = -1;
 897
 898        /* pbase-tree-cache acts as a limited hashtable.
 899         * your object will be found at your index or within a few
 900         * slots after that slot if it is cached.
 901         */
 902        for (neigh = 0; neigh < 8; neigh++) {
 903                ent = pbase_tree_cache[my_ix];
 904                if (ent && !hashcmp(ent->sha1, sha1)) {
 905                        ent->ref++;
 906                        return ent;
 907                }
 908                else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 909                         ((0 <= available_ix) &&
 910                          (!ent && pbase_tree_cache[available_ix])))
 911                        available_ix = my_ix;
 912                if (!ent)
 913                        break;
 914                my_ix = pbase_tree_cache_ix_incr(my_ix);
 915        }
 916
 917        /* Did not find one.  Either we got a bogus request or
 918         * we need to read and perhaps cache.
 919         */
 920        data = read_sha1_file(sha1, &type, &size);
 921        if (!data)
 922                return NULL;
 923        if (type != OBJ_TREE) {
 924                free(data);
 925                return NULL;
 926        }
 927
 928        /* We need to either cache or return a throwaway copy */
 929
 930        if (available_ix < 0)
 931                ent = NULL;
 932        else {
 933                ent = pbase_tree_cache[available_ix];
 934                my_ix = available_ix;
 935        }
 936
 937        if (!ent) {
 938                nent = xmalloc(sizeof(*nent));
 939                nent->temporary = (available_ix < 0);
 940        }
 941        else {
 942                /* evict and reuse */
 943                free(ent->tree_data);
 944                nent = ent;
 945        }
 946        hashcpy(nent->sha1, sha1);
 947        nent->tree_data = data;
 948        nent->tree_size = size;
 949        nent->ref = 1;
 950        if (!nent->temporary)
 951                pbase_tree_cache[my_ix] = nent;
 952        return nent;
 953}
 954
 955static void pbase_tree_put(struct pbase_tree_cache *cache)
 956{
 957        if (!cache->temporary) {
 958                cache->ref--;
 959                return;
 960        }
 961        free(cache->tree_data);
 962        free(cache);
 963}
 964
 965static int name_cmp_len(const char *name)
 966{
 967        int i;
 968        for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 969                ;
 970        return i;
 971}
 972
 973static void add_pbase_object(struct tree_desc *tree,
 974                             const char *name,
 975                             int cmplen,
 976                             const char *fullname)
 977{
 978        struct name_entry entry;
 979        int cmp;
 980
 981        while (tree_entry(tree,&entry)) {
 982                cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
 983                      memcmp(name, entry.path, cmplen);
 984                if (cmp > 0)
 985                        continue;
 986                if (cmp < 0)
 987                        return;
 988                if (name[cmplen] != '/') {
 989                        add_object_entry(entry.sha1,
 990                                         S_ISDIR(entry.mode) ? OBJ_TREE : OBJ_BLOB,
 991                                         fullname, 1);
 992                        return;
 993                }
 994                if (S_ISDIR(entry.mode)) {
 995                        struct tree_desc sub;
 996                        struct pbase_tree_cache *tree;
 997                        const char *down = name+cmplen+1;
 998                        int downlen = name_cmp_len(down);
 999
1000                        tree = pbase_tree_get(entry.sha1);
1001                        if (!tree)
1002                                return;
1003                        init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1004
1005                        add_pbase_object(&sub, down, downlen, fullname);
1006                        pbase_tree_put(tree);
1007                }
1008        }
1009}
1010
1011static unsigned *done_pbase_paths;
1012static int done_pbase_paths_num;
1013static int done_pbase_paths_alloc;
1014static int done_pbase_path_pos(unsigned hash)
1015{
1016        int lo = 0;
1017        int hi = done_pbase_paths_num;
1018        while (lo < hi) {
1019                int mi = (hi + lo) / 2;
1020                if (done_pbase_paths[mi] == hash)
1021                        return mi;
1022                if (done_pbase_paths[mi] < hash)
1023                        hi = mi;
1024                else
1025                        lo = mi + 1;
1026        }
1027        return -lo-1;
1028}
1029
1030static int check_pbase_path(unsigned hash)
1031{
1032        int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1033        if (0 <= pos)
1034                return 1;
1035        pos = -pos - 1;
1036        if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1037                done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1038                done_pbase_paths = xrealloc(done_pbase_paths,
1039                                            done_pbase_paths_alloc *
1040                                            sizeof(unsigned));
1041        }
1042        done_pbase_paths_num++;
1043        if (pos < done_pbase_paths_num)
1044                memmove(done_pbase_paths + pos + 1,
1045                        done_pbase_paths + pos,
1046                        (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1047        done_pbase_paths[pos] = hash;
1048        return 0;
1049}
1050
1051static void add_preferred_base_object(const char *name)
1052{
1053        struct pbase_tree *it;
1054        int cmplen;
1055        unsigned hash = name_hash(name);
1056
1057        if (!num_preferred_base || check_pbase_path(hash))
1058                return;
1059
1060        cmplen = name_cmp_len(name);
1061        for (it = pbase_tree; it; it = it->next) {
1062                if (cmplen == 0) {
1063                        add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1064                }
1065                else {
1066                        struct tree_desc tree;
1067                        init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1068                        add_pbase_object(&tree, name, cmplen, name);
1069                }
1070        }
1071}
1072
1073static void add_preferred_base(unsigned char *sha1)
1074{
1075        struct pbase_tree *it;
1076        void *data;
1077        unsigned long size;
1078        unsigned char tree_sha1[20];
1079
1080        if (window <= num_preferred_base++)
1081                return;
1082
1083        data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1084        if (!data)
1085                return;
1086
1087        for (it = pbase_tree; it; it = it->next) {
1088                if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1089                        free(data);
1090                        return;
1091                }
1092        }
1093
1094        it = xcalloc(1, sizeof(*it));
1095        it->next = pbase_tree;
1096        pbase_tree = it;
1097
1098        hashcpy(it->pcache.sha1, tree_sha1);
1099        it->pcache.tree_data = data;
1100        it->pcache.tree_size = size;
1101}
1102
1103static void check_object(struct object_entry *entry)
1104{
1105        if (entry->in_pack) {
1106                struct packed_git *p = entry->in_pack;
1107                struct pack_window *w_curs = NULL;
1108                const unsigned char *base_ref = NULL;
1109                struct object_entry *base_entry;
1110                unsigned long used, used_0;
1111                unsigned int avail;
1112                off_t ofs;
1113                unsigned char *buf, c;
1114
1115                buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1116
1117                /*
1118                 * We want in_pack_type even if we do not reuse delta
1119                 * since non-delta representations could still be reused.
1120                 */
1121                used = unpack_object_header_gently(buf, avail,
1122                                                   &entry->in_pack_type,
1123                                                   &entry->size);
1124
1125                /*
1126                 * Determine if this is a delta and if so whether we can
1127                 * reuse it or not.  Otherwise let's find out as cheaply as
1128                 * possible what the actual type and size for this object is.
1129                 */
1130                switch (entry->in_pack_type) {
1131                default:
1132                        /* Not a delta hence we've already got all we need. */
1133                        entry->type = entry->in_pack_type;
1134                        entry->in_pack_header_size = used;
1135                        unuse_pack(&w_curs);
1136                        return;
1137                case OBJ_REF_DELTA:
1138                        if (!no_reuse_delta && !entry->preferred_base)
1139                                base_ref = use_pack(p, &w_curs,
1140                                                entry->in_pack_offset + used, NULL);
1141                        entry->in_pack_header_size = used + 20;
1142                        break;
1143                case OBJ_OFS_DELTA:
1144                        buf = use_pack(p, &w_curs,
1145                                       entry->in_pack_offset + used, NULL);
1146                        used_0 = 0;
1147                        c = buf[used_0++];
1148                        ofs = c & 127;
1149                        while (c & 128) {
1150                                ofs += 1;
1151                                if (!ofs || MSB(ofs, 7))
1152                                        die("delta base offset overflow in pack for %s",
1153                                            sha1_to_hex(entry->idx.sha1));
1154                                c = buf[used_0++];
1155                                ofs = (ofs << 7) + (c & 127);
1156                        }
1157                        if (ofs >= entry->in_pack_offset)
1158                                die("delta base offset out of bound for %s",
1159                                    sha1_to_hex(entry->idx.sha1));
1160                        ofs = entry->in_pack_offset - ofs;
1161                        if (!no_reuse_delta && !entry->preferred_base)
1162                                base_ref = find_packed_object_name(p, ofs);
1163                        entry->in_pack_header_size = used + used_0;
1164                        break;
1165                }
1166
1167                if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1168                        /*
1169                         * If base_ref was set above that means we wish to
1170                         * reuse delta data, and we even found that base
1171                         * in the list of objects we want to pack. Goodie!
1172                         *
1173                         * Depth value does not matter - find_deltas() will
1174                         * never consider reused delta as the base object to
1175                         * deltify other objects against, in order to avoid
1176                         * circular deltas.
1177                         */
1178                        entry->type = entry->in_pack_type;
1179                        entry->delta = base_entry;
1180                        entry->delta_sibling = base_entry->delta_child;
1181                        base_entry->delta_child = entry;
1182                        unuse_pack(&w_curs);
1183                        return;
1184                }
1185
1186                if (entry->type) {
1187                        /*
1188                         * This must be a delta and we already know what the
1189                         * final object type is.  Let's extract the actual
1190                         * object size from the delta header.
1191                         */
1192                        entry->size = get_size_from_delta(p, &w_curs,
1193                                        entry->in_pack_offset + entry->in_pack_header_size);
1194                        unuse_pack(&w_curs);
1195                        return;
1196                }
1197
1198                /*
1199                 * No choice but to fall back to the recursive delta walk
1200                 * with sha1_object_info() to find about the object type
1201                 * at this point...
1202                 */
1203                unuse_pack(&w_curs);
1204        }
1205
1206        entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1207        if (entry->type < 0)
1208                die("unable to get type of object %s",
1209                    sha1_to_hex(entry->idx.sha1));
1210}
1211
1212static int pack_offset_sort(const void *_a, const void *_b)
1213{
1214        const struct object_entry *a = *(struct object_entry **)_a;
1215        const struct object_entry *b = *(struct object_entry **)_b;
1216
1217        /* avoid filesystem trashing with loose objects */
1218        if (!a->in_pack && !b->in_pack)
1219                return hashcmp(a->idx.sha1, b->idx.sha1);
1220
1221        if (a->in_pack < b->in_pack)
1222                return -1;
1223        if (a->in_pack > b->in_pack)
1224                return 1;
1225        return a->in_pack_offset < b->in_pack_offset ? -1 :
1226                        (a->in_pack_offset > b->in_pack_offset);
1227}
1228
1229static void get_object_details(void)
1230{
1231        uint32_t i;
1232        struct object_entry **sorted_by_offset;
1233
1234        sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1235        for (i = 0; i < nr_objects; i++)
1236                sorted_by_offset[i] = objects + i;
1237        qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1238
1239        prepare_pack_ix();
1240        for (i = 0; i < nr_objects; i++)
1241                check_object(sorted_by_offset[i]);
1242        free(sorted_by_offset);
1243}
1244
1245static int type_size_sort(const void *_a, const void *_b)
1246{
1247        const struct object_entry *a = *(struct object_entry **)_a;
1248        const struct object_entry *b = *(struct object_entry **)_b;
1249
1250        if (a->type < b->type)
1251                return -1;
1252        if (a->type > b->type)
1253                return 1;
1254        if (a->hash < b->hash)
1255                return -1;
1256        if (a->hash > b->hash)
1257                return 1;
1258        if (a->preferred_base < b->preferred_base)
1259                return -1;
1260        if (a->preferred_base > b->preferred_base)
1261                return 1;
1262        if (a->size < b->size)
1263                return -1;
1264        if (a->size > b->size)
1265                return 1;
1266        return a > b ? -1 : (a < b);  /* newest last */
1267}
1268
1269struct unpacked {
1270        struct object_entry *entry;
1271        void *data;
1272        struct delta_index *index;
1273};
1274
1275static int delta_cacheable(struct unpacked *trg, struct unpacked *src,
1276                            unsigned long src_size, unsigned long trg_size,
1277                            unsigned long delta_size)
1278{
1279        if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1280                return 0;
1281
1282        if (delta_size < cache_max_small_delta_size)
1283                return 1;
1284
1285        /* cache delta, if objects are large enough compared to delta size */
1286        if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1287                return 1;
1288
1289        return 0;
1290}
1291
1292/*
1293 * We search for deltas _backwards_ in a list sorted by type and
1294 * by size, so that we see progressively smaller and smaller files.
1295 * That's because we prefer deltas to be from the bigger file
1296 * to the smaller - deletes are potentially cheaper, but perhaps
1297 * more importantly, the bigger file is likely the more recent
1298 * one.
1299 */
1300static int try_delta(struct unpacked *trg, struct unpacked *src,
1301                     unsigned max_depth)
1302{
1303        struct object_entry *trg_entry = trg->entry;
1304        struct object_entry *src_entry = src->entry;
1305        unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1306        enum object_type type;
1307        void *delta_buf;
1308
1309        /* Don't bother doing diffs between different types */
1310        if (trg_entry->type != src_entry->type)
1311                return -1;
1312
1313        /* We do not compute delta to *create* objects we are not
1314         * going to pack.
1315         */
1316        if (trg_entry->preferred_base)
1317                return -1;
1318
1319        /*
1320         * We do not bother to try a delta that we discarded
1321         * on an earlier try, but only when reusing delta data.
1322         */
1323        if (!no_reuse_delta && trg_entry->in_pack &&
1324            trg_entry->in_pack == src_entry->in_pack &&
1325            trg_entry->in_pack_type != OBJ_REF_DELTA &&
1326            trg_entry->in_pack_type != OBJ_OFS_DELTA)
1327                return 0;
1328
1329        /* Let's not bust the allowed depth. */
1330        if (src_entry->depth >= max_depth)
1331                return 0;
1332
1333        /* Now some size filtering heuristics. */
1334        trg_size = trg_entry->size;
1335        max_size = trg_size/2 - 20;
1336        max_size = max_size * (max_depth - src_entry->depth) / max_depth;
1337        if (max_size == 0)
1338                return 0;
1339        if (trg_entry->delta && trg_entry->delta_size <= max_size)
1340                max_size = trg_entry->delta_size-1;
1341        src_size = src_entry->size;
1342        sizediff = src_size < trg_size ? trg_size - src_size : 0;
1343        if (sizediff >= max_size)
1344                return 0;
1345
1346        /* Load data if not already done */
1347        if (!trg->data) {
1348                trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1349                if (sz != trg_size)
1350                        die("object %s inconsistent object length (%lu vs %lu)",
1351                            sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1352        }
1353        if (!src->data) {
1354                src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1355                if (sz != src_size)
1356                        die("object %s inconsistent object length (%lu vs %lu)",
1357                            sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1358        }
1359        if (!src->index) {
1360                src->index = create_delta_index(src->data, src_size);
1361                if (!src->index) {
1362                        static int warned = 0;
1363                        if (!warned++)
1364                                warning("suboptimal pack - out of memory");
1365                        return 0;
1366                }
1367        }
1368
1369        delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1370        if (!delta_buf)
1371                return 0;
1372
1373        if (trg_entry->delta_data) {
1374                delta_cache_size -= trg_entry->delta_size;
1375                free(trg_entry->delta_data);
1376        }
1377        trg_entry->delta_data = 0;
1378        trg_entry->delta = src_entry;
1379        trg_entry->delta_size = delta_size;
1380        trg_entry->depth = src_entry->depth + 1;
1381
1382        if (delta_cacheable(src, trg, src_size, trg_size, delta_size)) {
1383                trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1384                delta_cache_size += trg_entry->delta_size;
1385        } else
1386                free(delta_buf);
1387        return 1;
1388}
1389
1390static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1391{
1392        struct object_entry *child = me->delta_child;
1393        unsigned int m = n;
1394        while (child) {
1395                unsigned int c = check_delta_limit(child, n + 1);
1396                if (m < c)
1397                        m = c;
1398                child = child->delta_sibling;
1399        }
1400        return m;
1401}
1402
1403static void find_deltas(struct object_entry **list, int window, int depth)
1404{
1405        uint32_t i = nr_objects, idx = 0, processed = 0;
1406        unsigned int array_size = window * sizeof(struct unpacked);
1407        struct unpacked *array;
1408        int max_depth;
1409
1410        if (!nr_objects)
1411                return;
1412        array = xmalloc(array_size);
1413        memset(array, 0, array_size);
1414        if (progress)
1415                start_progress(&progress_state, "Deltifying %u objects...", "", nr_result);
1416
1417        do {
1418                struct object_entry *entry = list[--i];
1419                struct unpacked *n = array + idx;
1420                int j;
1421
1422                if (!entry->preferred_base)
1423                        processed++;
1424
1425                if (progress)
1426                        display_progress(&progress_state, processed);
1427
1428                if (entry->delta)
1429                        /* This happens if we decided to reuse existing
1430                         * delta from a pack.  "!no_reuse_delta &&" is implied.
1431                         */
1432                        continue;
1433
1434                if (entry->size < 50)
1435                        continue;
1436
1437                if (entry->no_try_delta)
1438                        continue;
1439
1440                free_delta_index(n->index);
1441                n->index = NULL;
1442                free(n->data);
1443                n->data = NULL;
1444                n->entry = entry;
1445
1446                /*
1447                 * If the current object is at pack edge, take the depth the
1448                 * objects that depend on the current object into account
1449                 * otherwise they would become too deep.
1450                 */
1451                max_depth = depth;
1452                if (entry->delta_child) {
1453                        max_depth -= check_delta_limit(entry, 0);
1454                        if (max_depth <= 0)
1455                                goto next;
1456                }
1457
1458                j = window;
1459                while (--j > 0) {
1460                        uint32_t other_idx = idx + j;
1461                        struct unpacked *m;
1462                        if (other_idx >= window)
1463                                other_idx -= window;
1464                        m = array + other_idx;
1465                        if (!m->entry)
1466                                break;
1467                        if (try_delta(n, m, max_depth) < 0)
1468                                break;
1469                }
1470
1471                /* if we made n a delta, and if n is already at max
1472                 * depth, leaving it in the window is pointless.  we
1473                 * should evict it first.
1474                 */
1475                if (entry->delta && depth <= entry->depth)
1476                        continue;
1477
1478                next:
1479                idx++;
1480                if (idx >= window)
1481                        idx = 0;
1482        } while (i > 0);
1483
1484        if (progress)
1485                stop_progress(&progress_state);
1486
1487        for (i = 0; i < window; ++i) {
1488                free_delta_index(array[i].index);
1489                free(array[i].data);
1490        }
1491        free(array);
1492}
1493
1494static void prepare_pack(int window, int depth)
1495{
1496        struct object_entry **delta_list;
1497        uint32_t i;
1498
1499        get_object_details();
1500
1501        if (!window || !depth)
1502                return;
1503
1504        delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1505        for (i = 0; i < nr_objects; i++)
1506                delta_list[i] = objects + i;
1507        qsort(delta_list, nr_objects, sizeof(*delta_list), type_size_sort);
1508        find_deltas(delta_list, window+1, depth);
1509        free(delta_list);
1510}
1511
1512static int git_pack_config(const char *k, const char *v)
1513{
1514        if(!strcmp(k, "pack.window")) {
1515                window = git_config_int(k, v);
1516                return 0;
1517        }
1518        if(!strcmp(k, "pack.depth")) {
1519                depth = git_config_int(k, v);
1520                return 0;
1521        }
1522        if (!strcmp(k, "pack.compression")) {
1523                int level = git_config_int(k, v);
1524                if (level == -1)
1525                        level = Z_DEFAULT_COMPRESSION;
1526                else if (level < 0 || level > Z_BEST_COMPRESSION)
1527                        die("bad pack compression level %d", level);
1528                pack_compression_level = level;
1529                pack_compression_seen = 1;
1530                return 0;
1531        }
1532        if (!strcmp(k, "pack.deltacachesize")) {
1533                max_delta_cache_size = git_config_int(k, v);
1534                return 0;
1535        }
1536        if (!strcmp(k, "pack.deltacachelimit")) {
1537                cache_max_small_delta_size = git_config_int(k, v);
1538                return 0;
1539        }
1540        return git_default_config(k, v);
1541}
1542
1543static void read_object_list_from_stdin(void)
1544{
1545        char line[40 + 1 + PATH_MAX + 2];
1546        unsigned char sha1[20];
1547
1548        for (;;) {
1549                if (!fgets(line, sizeof(line), stdin)) {
1550                        if (feof(stdin))
1551                                break;
1552                        if (!ferror(stdin))
1553                                die("fgets returned NULL, not EOF, not error!");
1554                        if (errno != EINTR)
1555                                die("fgets: %s", strerror(errno));
1556                        clearerr(stdin);
1557                        continue;
1558                }
1559                if (line[0] == '-') {
1560                        if (get_sha1_hex(line+1, sha1))
1561                                die("expected edge sha1, got garbage:\n %s",
1562                                    line);
1563                        add_preferred_base(sha1);
1564                        continue;
1565                }
1566                if (get_sha1_hex(line, sha1))
1567                        die("expected sha1, got garbage:\n %s", line);
1568
1569                add_preferred_base_object(line+41);
1570                add_object_entry(sha1, 0, line+41, 0);
1571        }
1572}
1573
1574static void show_commit(struct commit *commit)
1575{
1576        add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
1577}
1578
1579static void show_object(struct object_array_entry *p)
1580{
1581        add_preferred_base_object(p->name);
1582        add_object_entry(p->item->sha1, p->item->type, p->name, 0);
1583}
1584
1585static void show_edge(struct commit *commit)
1586{
1587        add_preferred_base(commit->object.sha1);
1588}
1589
1590static void get_object_list(int ac, const char **av)
1591{
1592        struct rev_info revs;
1593        char line[1000];
1594        int flags = 0;
1595
1596        init_revisions(&revs, NULL);
1597        save_commit_buffer = 0;
1598        track_object_refs = 0;
1599        setup_revisions(ac, av, &revs, NULL);
1600
1601        while (fgets(line, sizeof(line), stdin) != NULL) {
1602                int len = strlen(line);
1603                if (line[len - 1] == '\n')
1604                        line[--len] = 0;
1605                if (!len)
1606                        break;
1607                if (*line == '-') {
1608                        if (!strcmp(line, "--not")) {
1609                                flags ^= UNINTERESTING;
1610                                continue;
1611                        }
1612                        die("not a rev '%s'", line);
1613                }
1614                if (handle_revision_arg(line, &revs, flags, 1))
1615                        die("bad revision '%s'", line);
1616        }
1617
1618        prepare_revision_walk(&revs);
1619        mark_edges_uninteresting(revs.commits, &revs, show_edge);
1620        traverse_commit_list(&revs, show_commit, show_object);
1621}
1622
1623static int adjust_perm(const char *path, mode_t mode)
1624{
1625        if (chmod(path, mode))
1626                return -1;
1627        return adjust_shared_perm(path);
1628}
1629
1630int cmd_pack_objects(int argc, const char **argv, const char *prefix)
1631{
1632        int use_internal_rev_list = 0;
1633        int thin = 0;
1634        uint32_t i;
1635        const char **rp_av;
1636        int rp_ac_alloc = 64;
1637        int rp_ac;
1638
1639        rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
1640
1641        rp_av[0] = "pack-objects";
1642        rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
1643        rp_ac = 2;
1644
1645        git_config(git_pack_config);
1646        if (!pack_compression_seen && core_compression_seen)
1647                pack_compression_level = core_compression_level;
1648
1649        progress = isatty(2);
1650        for (i = 1; i < argc; i++) {
1651                const char *arg = argv[i];
1652
1653                if (*arg != '-')
1654                        break;
1655
1656                if (!strcmp("--non-empty", arg)) {
1657                        non_empty = 1;
1658                        continue;
1659                }
1660                if (!strcmp("--local", arg)) {
1661                        local = 1;
1662                        continue;
1663                }
1664                if (!strcmp("--incremental", arg)) {
1665                        incremental = 1;
1666                        continue;
1667                }
1668                if (!prefixcmp(arg, "--compression=")) {
1669                        char *end;
1670                        int level = strtoul(arg+14, &end, 0);
1671                        if (!arg[14] || *end)
1672                                usage(pack_usage);
1673                        if (level == -1)
1674                                level = Z_DEFAULT_COMPRESSION;
1675                        else if (level < 0 || level > Z_BEST_COMPRESSION)
1676                                die("bad pack compression level %d", level);
1677                        pack_compression_level = level;
1678                        continue;
1679                }
1680                if (!prefixcmp(arg, "--max-pack-size=")) {
1681                        char *end;
1682                        pack_size_limit = strtoul(arg+16, &end, 0) * 1024 * 1024;
1683                        if (!arg[16] || *end)
1684                                usage(pack_usage);
1685                        continue;
1686                }
1687                if (!prefixcmp(arg, "--window=")) {
1688                        char *end;
1689                        window = strtoul(arg+9, &end, 0);
1690                        if (!arg[9] || *end)
1691                                usage(pack_usage);
1692                        continue;
1693                }
1694                if (!prefixcmp(arg, "--depth=")) {
1695                        char *end;
1696                        depth = strtoul(arg+8, &end, 0);
1697                        if (!arg[8] || *end)
1698                                usage(pack_usage);
1699                        continue;
1700                }
1701                if (!strcmp("--progress", arg)) {
1702                        progress = 1;
1703                        continue;
1704                }
1705                if (!strcmp("--all-progress", arg)) {
1706                        progress = 2;
1707                        continue;
1708                }
1709                if (!strcmp("-q", arg)) {
1710                        progress = 0;
1711                        continue;
1712                }
1713                if (!strcmp("--no-reuse-delta", arg)) {
1714                        no_reuse_delta = 1;
1715                        continue;
1716                }
1717                if (!strcmp("--no-reuse-object", arg)) {
1718                        no_reuse_object = no_reuse_delta = 1;
1719                        continue;
1720                }
1721                if (!strcmp("--delta-base-offset", arg)) {
1722                        allow_ofs_delta = 1;
1723                        continue;
1724                }
1725                if (!strcmp("--stdout", arg)) {
1726                        pack_to_stdout = 1;
1727                        continue;
1728                }
1729                if (!strcmp("--revs", arg)) {
1730                        use_internal_rev_list = 1;
1731                        continue;
1732                }
1733                if (!strcmp("--unpacked", arg) ||
1734                    !prefixcmp(arg, "--unpacked=") ||
1735                    !strcmp("--reflog", arg) ||
1736                    !strcmp("--all", arg)) {
1737                        use_internal_rev_list = 1;
1738                        if (rp_ac >= rp_ac_alloc - 1) {
1739                                rp_ac_alloc = alloc_nr(rp_ac_alloc);
1740                                rp_av = xrealloc(rp_av,
1741                                                 rp_ac_alloc * sizeof(*rp_av));
1742                        }
1743                        rp_av[rp_ac++] = arg;
1744                        continue;
1745                }
1746                if (!strcmp("--thin", arg)) {
1747                        use_internal_rev_list = 1;
1748                        thin = 1;
1749                        rp_av[1] = "--objects-edge";
1750                        continue;
1751                }
1752                if (!prefixcmp(arg, "--index-version=")) {
1753                        char *c;
1754                        pack_idx_default_version = strtoul(arg + 16, &c, 10);
1755                        if (pack_idx_default_version > 2)
1756                                die("bad %s", arg);
1757                        if (*c == ',')
1758                                pack_idx_off32_limit = strtoul(c+1, &c, 0);
1759                        if (*c || pack_idx_off32_limit & 0x80000000)
1760                                die("bad %s", arg);
1761                        continue;
1762                }
1763                usage(pack_usage);
1764        }
1765
1766        /* Traditionally "pack-objects [options] base extra" failed;
1767         * we would however want to take refs parameter that would
1768         * have been given to upstream rev-list ourselves, which means
1769         * we somehow want to say what the base name is.  So the
1770         * syntax would be:
1771         *
1772         * pack-objects [options] base <refs...>
1773         *
1774         * in other words, we would treat the first non-option as the
1775         * base_name and send everything else to the internal revision
1776         * walker.
1777         */
1778
1779        if (!pack_to_stdout)
1780                base_name = argv[i++];
1781
1782        if (pack_to_stdout != !base_name)
1783                usage(pack_usage);
1784
1785        if (pack_to_stdout && pack_size_limit)
1786                die("--max-pack-size cannot be used to build a pack for transfer.");
1787
1788        if (!pack_to_stdout && thin)
1789                die("--thin cannot be used to build an indexable pack.");
1790
1791        prepare_packed_git();
1792
1793        if (progress)
1794                start_progress(&progress_state, "Generating pack...",
1795                               "Counting objects: ", 0);
1796        if (!use_internal_rev_list)
1797                read_object_list_from_stdin();
1798        else {
1799                rp_av[rp_ac] = NULL;
1800                get_object_list(rp_ac, rp_av);
1801        }
1802        if (progress) {
1803                stop_progress(&progress_state);
1804                fprintf(stderr, "Done counting %u objects.\n", nr_objects);
1805        }
1806
1807        if (non_empty && !nr_result)
1808                return 0;
1809        if (progress && (nr_objects != nr_result))
1810                fprintf(stderr, "Result has %u objects.\n", nr_result);
1811        if (nr_result)
1812                prepare_pack(window, depth);
1813        write_pack_file();
1814        if (progress)
1815                fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
1816                        written, written_delta, reused, reused_delta);
1817        return 0;
1818}