builtin / pack-objects.con commit multi-pack-index: provide more helpful usage info (6d68e6a)
   1#include "builtin.h"
   2#include "cache.h"
   3#include "repository.h"
   4#include "config.h"
   5#include "attr.h"
   6#include "object.h"
   7#include "blob.h"
   8#include "commit.h"
   9#include "tag.h"
  10#include "tree.h"
  11#include "delta.h"
  12#include "pack.h"
  13#include "pack-revindex.h"
  14#include "csum-file.h"
  15#include "tree-walk.h"
  16#include "diff.h"
  17#include "revision.h"
  18#include "list-objects.h"
  19#include "list-objects-filter.h"
  20#include "list-objects-filter-options.h"
  21#include "pack-objects.h"
  22#include "progress.h"
  23#include "refs.h"
  24#include "streaming.h"
  25#include "thread-utils.h"
  26#include "pack-bitmap.h"
  27#include "reachable.h"
  28#include "sha1-array.h"
  29#include "argv-array.h"
  30#include "list.h"
  31#include "packfile.h"
  32#include "object-store.h"
  33#include "dir.h"
  34
  35#define IN_PACK(obj) oe_in_pack(&to_pack, obj)
  36#define SIZE(obj) oe_size(&to_pack, obj)
  37#define SET_SIZE(obj,size) oe_set_size(&to_pack, obj, size)
  38#define DELTA_SIZE(obj) oe_delta_size(&to_pack, obj)
  39#define DELTA(obj) oe_delta(&to_pack, obj)
  40#define DELTA_CHILD(obj) oe_delta_child(&to_pack, obj)
  41#define DELTA_SIBLING(obj) oe_delta_sibling(&to_pack, obj)
  42#define SET_DELTA(obj, val) oe_set_delta(&to_pack, obj, val)
  43#define SET_DELTA_SIZE(obj, val) oe_set_delta_size(&to_pack, obj, val)
  44#define SET_DELTA_CHILD(obj, val) oe_set_delta_child(&to_pack, obj, val)
  45#define SET_DELTA_SIBLING(obj, val) oe_set_delta_sibling(&to_pack, obj, val)
  46
  47static const char *pack_usage[] = {
  48        N_("git pack-objects --stdout [<options>...] [< <ref-list> | < <object-list>]"),
  49        N_("git pack-objects [<options>...] <base-name> [< <ref-list> | < <object-list>]"),
  50        NULL
  51};
  52
  53/*
  54 * Objects we are going to pack are collected in the `to_pack` structure.
  55 * It contains an array (dynamically expanded) of the object data, and a map
  56 * that can resolve SHA1s to their position in the array.
  57 */
  58static struct packing_data to_pack;
  59
  60static struct pack_idx_entry **written_list;
  61static uint32_t nr_result, nr_written, nr_seen;
  62
  63static int non_empty;
  64static int reuse_delta = 1, reuse_object = 1;
  65static int keep_unreachable, unpack_unreachable, include_tag;
  66static timestamp_t unpack_unreachable_expiration;
  67static int pack_loose_unreachable;
  68static int local;
  69static int have_non_local_packs;
  70static int incremental;
  71static int ignore_packed_keep_on_disk;
  72static int ignore_packed_keep_in_core;
  73static int allow_ofs_delta;
  74static struct pack_idx_option pack_idx_opts;
  75static const char *base_name;
  76static int progress = 1;
  77static int window = 10;
  78static unsigned long pack_size_limit;
  79static int depth = 50;
  80static int delta_search_threads;
  81static int pack_to_stdout;
  82static int num_preferred_base;
  83static struct progress *progress_state;
  84
  85static struct packed_git *reuse_packfile;
  86static uint32_t reuse_packfile_objects;
  87static off_t reuse_packfile_offset;
  88
  89static int use_bitmap_index_default = 1;
  90static int use_bitmap_index = -1;
  91static int write_bitmap_index;
  92static uint16_t write_bitmap_options;
  93
  94static int exclude_promisor_objects;
  95
  96static unsigned long delta_cache_size = 0;
  97static unsigned long max_delta_cache_size = DEFAULT_DELTA_CACHE_SIZE;
  98static unsigned long cache_max_small_delta_size = 1000;
  99
 100static unsigned long window_memory_limit = 0;
 101
 102static struct list_objects_filter_options filter_options;
 103
 104enum missing_action {
 105        MA_ERROR = 0,      /* fail if any missing objects are encountered */
 106        MA_ALLOW_ANY,      /* silently allow ALL missing objects */
 107        MA_ALLOW_PROMISOR, /* silently allow all missing PROMISOR objects */
 108};
 109static enum missing_action arg_missing_action;
 110static show_object_fn fn_show_object;
 111
 112/*
 113 * stats
 114 */
 115static uint32_t written, written_delta;
 116static uint32_t reused, reused_delta;
 117
 118/*
 119 * Indexed commits
 120 */
 121static struct commit **indexed_commits;
 122static unsigned int indexed_commits_nr;
 123static unsigned int indexed_commits_alloc;
 124
 125static void index_commit_for_bitmap(struct commit *commit)
 126{
 127        if (indexed_commits_nr >= indexed_commits_alloc) {
 128                indexed_commits_alloc = (indexed_commits_alloc + 32) * 2;
 129                REALLOC_ARRAY(indexed_commits, indexed_commits_alloc);
 130        }
 131
 132        indexed_commits[indexed_commits_nr++] = commit;
 133}
 134
 135static void *get_delta(struct object_entry *entry)
 136{
 137        unsigned long size, base_size, delta_size;
 138        void *buf, *base_buf, *delta_buf;
 139        enum object_type type;
 140
 141        buf = read_object_file(&entry->idx.oid, &type, &size);
 142        if (!buf)
 143                die(_("unable to read %s"), oid_to_hex(&entry->idx.oid));
 144        base_buf = read_object_file(&DELTA(entry)->idx.oid, &type,
 145                                    &base_size);
 146        if (!base_buf)
 147                die("unable to read %s",
 148                    oid_to_hex(&DELTA(entry)->idx.oid));
 149        delta_buf = diff_delta(base_buf, base_size,
 150                               buf, size, &delta_size, 0);
 151        /*
 152         * We succesfully computed this delta once but dropped it for
 153         * memory reasons. Something is very wrong if this time we
 154         * recompute and create a different delta.
 155         */
 156        if (!delta_buf || delta_size != DELTA_SIZE(entry))
 157                BUG("delta size changed");
 158        free(buf);
 159        free(base_buf);
 160        return delta_buf;
 161}
 162
 163static unsigned long do_compress(void **pptr, unsigned long size)
 164{
 165        git_zstream stream;
 166        void *in, *out;
 167        unsigned long maxsize;
 168
 169        git_deflate_init(&stream, pack_compression_level);
 170        maxsize = git_deflate_bound(&stream, size);
 171
 172        in = *pptr;
 173        out = xmalloc(maxsize);
 174        *pptr = out;
 175
 176        stream.next_in = in;
 177        stream.avail_in = size;
 178        stream.next_out = out;
 179        stream.avail_out = maxsize;
 180        while (git_deflate(&stream, Z_FINISH) == Z_OK)
 181                ; /* nothing */
 182        git_deflate_end(&stream);
 183
 184        free(in);
 185        return stream.total_out;
 186}
 187
 188static unsigned long write_large_blob_data(struct git_istream *st, struct hashfile *f,
 189                                           const struct object_id *oid)
 190{
 191        git_zstream stream;
 192        unsigned char ibuf[1024 * 16];
 193        unsigned char obuf[1024 * 16];
 194        unsigned long olen = 0;
 195
 196        git_deflate_init(&stream, pack_compression_level);
 197
 198        for (;;) {
 199                ssize_t readlen;
 200                int zret = Z_OK;
 201                readlen = read_istream(st, ibuf, sizeof(ibuf));
 202                if (readlen == -1)
 203                        die(_("unable to read %s"), oid_to_hex(oid));
 204
 205                stream.next_in = ibuf;
 206                stream.avail_in = readlen;
 207                while ((stream.avail_in || readlen == 0) &&
 208                       (zret == Z_OK || zret == Z_BUF_ERROR)) {
 209                        stream.next_out = obuf;
 210                        stream.avail_out = sizeof(obuf);
 211                        zret = git_deflate(&stream, readlen ? 0 : Z_FINISH);
 212                        hashwrite(f, obuf, stream.next_out - obuf);
 213                        olen += stream.next_out - obuf;
 214                }
 215                if (stream.avail_in)
 216                        die(_("deflate error (%d)"), zret);
 217                if (readlen == 0) {
 218                        if (zret != Z_STREAM_END)
 219                                die(_("deflate error (%d)"), zret);
 220                        break;
 221                }
 222        }
 223        git_deflate_end(&stream);
 224        return olen;
 225}
 226
 227/*
 228 * we are going to reuse the existing object data as is.  make
 229 * sure it is not corrupt.
 230 */
 231static int check_pack_inflate(struct packed_git *p,
 232                struct pack_window **w_curs,
 233                off_t offset,
 234                off_t len,
 235                unsigned long expect)
 236{
 237        git_zstream stream;
 238        unsigned char fakebuf[4096], *in;
 239        int st;
 240
 241        memset(&stream, 0, sizeof(stream));
 242        git_inflate_init(&stream);
 243        do {
 244                in = use_pack(p, w_curs, offset, &stream.avail_in);
 245                stream.next_in = in;
 246                stream.next_out = fakebuf;
 247                stream.avail_out = sizeof(fakebuf);
 248                st = git_inflate(&stream, Z_FINISH);
 249                offset += stream.next_in - in;
 250        } while (st == Z_OK || st == Z_BUF_ERROR);
 251        git_inflate_end(&stream);
 252        return (st == Z_STREAM_END &&
 253                stream.total_out == expect &&
 254                stream.total_in == len) ? 0 : -1;
 255}
 256
 257static void copy_pack_data(struct hashfile *f,
 258                struct packed_git *p,
 259                struct pack_window **w_curs,
 260                off_t offset,
 261                off_t len)
 262{
 263        unsigned char *in;
 264        unsigned long avail;
 265
 266        while (len) {
 267                in = use_pack(p, w_curs, offset, &avail);
 268                if (avail > len)
 269                        avail = (unsigned long)len;
 270                hashwrite(f, in, avail);
 271                offset += avail;
 272                len -= avail;
 273        }
 274}
 275
 276/* Return 0 if we will bust the pack-size limit */
 277static unsigned long write_no_reuse_object(struct hashfile *f, struct object_entry *entry,
 278                                           unsigned long limit, int usable_delta)
 279{
 280        unsigned long size, datalen;
 281        unsigned char header[MAX_PACK_OBJECT_HEADER],
 282                      dheader[MAX_PACK_OBJECT_HEADER];
 283        unsigned hdrlen;
 284        enum object_type type;
 285        void *buf;
 286        struct git_istream *st = NULL;
 287        const unsigned hashsz = the_hash_algo->rawsz;
 288
 289        if (!usable_delta) {
 290                if (oe_type(entry) == OBJ_BLOB &&
 291                    oe_size_greater_than(&to_pack, entry, big_file_threshold) &&
 292                    (st = open_istream(&entry->idx.oid, &type, &size, NULL)) != NULL)
 293                        buf = NULL;
 294                else {
 295                        buf = read_object_file(&entry->idx.oid, &type, &size);
 296                        if (!buf)
 297                                die(_("unable to read %s"),
 298                                    oid_to_hex(&entry->idx.oid));
 299                }
 300                /*
 301                 * make sure no cached delta data remains from a
 302                 * previous attempt before a pack split occurred.
 303                 */
 304                FREE_AND_NULL(entry->delta_data);
 305                entry->z_delta_size = 0;
 306        } else if (entry->delta_data) {
 307                size = DELTA_SIZE(entry);
 308                buf = entry->delta_data;
 309                entry->delta_data = NULL;
 310                type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 311                        OBJ_OFS_DELTA : OBJ_REF_DELTA;
 312        } else {
 313                buf = get_delta(entry);
 314                size = DELTA_SIZE(entry);
 315                type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 316                        OBJ_OFS_DELTA : OBJ_REF_DELTA;
 317        }
 318
 319        if (st) /* large blob case, just assume we don't compress well */
 320                datalen = size;
 321        else if (entry->z_delta_size)
 322                datalen = entry->z_delta_size;
 323        else
 324                datalen = do_compress(&buf, size);
 325
 326        /*
 327         * The object header is a byte of 'type' followed by zero or
 328         * more bytes of length.
 329         */
 330        hdrlen = encode_in_pack_object_header(header, sizeof(header),
 331                                              type, size);
 332
 333        if (type == OBJ_OFS_DELTA) {
 334                /*
 335                 * Deltas with relative base contain an additional
 336                 * encoding of the relative offset for the delta
 337                 * base from this object's position in the pack.
 338                 */
 339                off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 340                unsigned pos = sizeof(dheader) - 1;
 341                dheader[pos] = ofs & 127;
 342                while (ofs >>= 7)
 343                        dheader[--pos] = 128 | (--ofs & 127);
 344                if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 345                        if (st)
 346                                close_istream(st);
 347                        free(buf);
 348                        return 0;
 349                }
 350                hashwrite(f, header, hdrlen);
 351                hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 352                hdrlen += sizeof(dheader) - pos;
 353        } else if (type == OBJ_REF_DELTA) {
 354                /*
 355                 * Deltas with a base reference contain
 356                 * additional bytes for the base object ID.
 357                 */
 358                if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 359                        if (st)
 360                                close_istream(st);
 361                        free(buf);
 362                        return 0;
 363                }
 364                hashwrite(f, header, hdrlen);
 365                hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
 366                hdrlen += hashsz;
 367        } else {
 368                if (limit && hdrlen + datalen + hashsz >= limit) {
 369                        if (st)
 370                                close_istream(st);
 371                        free(buf);
 372                        return 0;
 373                }
 374                hashwrite(f, header, hdrlen);
 375        }
 376        if (st) {
 377                datalen = write_large_blob_data(st, f, &entry->idx.oid);
 378                close_istream(st);
 379        } else {
 380                hashwrite(f, buf, datalen);
 381                free(buf);
 382        }
 383
 384        return hdrlen + datalen;
 385}
 386
 387/* Return 0 if we will bust the pack-size limit */
 388static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
 389                                unsigned long limit, int usable_delta)
 390{
 391        struct packed_git *p = IN_PACK(entry);
 392        struct pack_window *w_curs = NULL;
 393        struct revindex_entry *revidx;
 394        off_t offset;
 395        enum object_type type = oe_type(entry);
 396        off_t datalen;
 397        unsigned char header[MAX_PACK_OBJECT_HEADER],
 398                      dheader[MAX_PACK_OBJECT_HEADER];
 399        unsigned hdrlen;
 400        const unsigned hashsz = the_hash_algo->rawsz;
 401        unsigned long entry_size = SIZE(entry);
 402
 403        if (DELTA(entry))
 404                type = (allow_ofs_delta && DELTA(entry)->idx.offset) ?
 405                        OBJ_OFS_DELTA : OBJ_REF_DELTA;
 406        hdrlen = encode_in_pack_object_header(header, sizeof(header),
 407                                              type, entry_size);
 408
 409        offset = entry->in_pack_offset;
 410        revidx = find_pack_revindex(p, offset);
 411        datalen = revidx[1].offset - offset;
 412        if (!pack_to_stdout && p->index_version > 1 &&
 413            check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 414                error(_("bad packed object CRC for %s"),
 415                      oid_to_hex(&entry->idx.oid));
 416                unuse_pack(&w_curs);
 417                return write_no_reuse_object(f, entry, limit, usable_delta);
 418        }
 419
 420        offset += entry->in_pack_header_size;
 421        datalen -= entry->in_pack_header_size;
 422
 423        if (!pack_to_stdout && p->index_version == 1 &&
 424            check_pack_inflate(p, &w_curs, offset, datalen, entry_size)) {
 425                error(_("corrupt packed object for %s"),
 426                      oid_to_hex(&entry->idx.oid));
 427                unuse_pack(&w_curs);
 428                return write_no_reuse_object(f, entry, limit, usable_delta);
 429        }
 430
 431        if (type == OBJ_OFS_DELTA) {
 432                off_t ofs = entry->idx.offset - DELTA(entry)->idx.offset;
 433                unsigned pos = sizeof(dheader) - 1;
 434                dheader[pos] = ofs & 127;
 435                while (ofs >>= 7)
 436                        dheader[--pos] = 128 | (--ofs & 127);
 437                if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
 438                        unuse_pack(&w_curs);
 439                        return 0;
 440                }
 441                hashwrite(f, header, hdrlen);
 442                hashwrite(f, dheader + pos, sizeof(dheader) - pos);
 443                hdrlen += sizeof(dheader) - pos;
 444                reused_delta++;
 445        } else if (type == OBJ_REF_DELTA) {
 446                if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
 447                        unuse_pack(&w_curs);
 448                        return 0;
 449                }
 450                hashwrite(f, header, hdrlen);
 451                hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
 452                hdrlen += hashsz;
 453                reused_delta++;
 454        } else {
 455                if (limit && hdrlen + datalen + hashsz >= limit) {
 456                        unuse_pack(&w_curs);
 457                        return 0;
 458                }
 459                hashwrite(f, header, hdrlen);
 460        }
 461        copy_pack_data(f, p, &w_curs, offset, datalen);
 462        unuse_pack(&w_curs);
 463        reused++;
 464        return hdrlen + datalen;
 465}
 466
 467/* Return 0 if we will bust the pack-size limit */
 468static off_t write_object(struct hashfile *f,
 469                          struct object_entry *entry,
 470                          off_t write_offset)
 471{
 472        unsigned long limit;
 473        off_t len;
 474        int usable_delta, to_reuse;
 475
 476        if (!pack_to_stdout)
 477                crc32_begin(f);
 478
 479        /* apply size limit if limited packsize and not first object */
 480        if (!pack_size_limit || !nr_written)
 481                limit = 0;
 482        else if (pack_size_limit <= write_offset)
 483                /*
 484                 * the earlier object did not fit the limit; avoid
 485                 * mistaking this with unlimited (i.e. limit = 0).
 486                 */
 487                limit = 1;
 488        else
 489                limit = pack_size_limit - write_offset;
 490
 491        if (!DELTA(entry))
 492                usable_delta = 0;       /* no delta */
 493        else if (!pack_size_limit)
 494               usable_delta = 1;        /* unlimited packfile */
 495        else if (DELTA(entry)->idx.offset == (off_t)-1)
 496                usable_delta = 0;       /* base was written to another pack */
 497        else if (DELTA(entry)->idx.offset)
 498                usable_delta = 1;       /* base already exists in this pack */
 499        else
 500                usable_delta = 0;       /* base could end up in another pack */
 501
 502        if (!reuse_object)
 503                to_reuse = 0;   /* explicit */
 504        else if (!IN_PACK(entry))
 505                to_reuse = 0;   /* can't reuse what we don't have */
 506        else if (oe_type(entry) == OBJ_REF_DELTA ||
 507                 oe_type(entry) == OBJ_OFS_DELTA)
 508                                /* check_object() decided it for us ... */
 509                to_reuse = usable_delta;
 510                                /* ... but pack split may override that */
 511        else if (oe_type(entry) != entry->in_pack_type)
 512                to_reuse = 0;   /* pack has delta which is unusable */
 513        else if (DELTA(entry))
 514                to_reuse = 0;   /* we want to pack afresh */
 515        else
 516                to_reuse = 1;   /* we have it in-pack undeltified,
 517                                 * and we do not need to deltify it.
 518                                 */
 519
 520        if (!to_reuse)
 521                len = write_no_reuse_object(f, entry, limit, usable_delta);
 522        else
 523                len = write_reuse_object(f, entry, limit, usable_delta);
 524        if (!len)
 525                return 0;
 526
 527        if (usable_delta)
 528                written_delta++;
 529        written++;
 530        if (!pack_to_stdout)
 531                entry->idx.crc32 = crc32_end(f);
 532        return len;
 533}
 534
 535enum write_one_status {
 536        WRITE_ONE_SKIP = -1, /* already written */
 537        WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 538        WRITE_ONE_WRITTEN = 1, /* normal */
 539        WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 540};
 541
 542static enum write_one_status write_one(struct hashfile *f,
 543                                       struct object_entry *e,
 544                                       off_t *offset)
 545{
 546        off_t size;
 547        int recursing;
 548
 549        /*
 550         * we set offset to 1 (which is an impossible value) to mark
 551         * the fact that this object is involved in "write its base
 552         * first before writing a deltified object" recursion.
 553         */
 554        recursing = (e->idx.offset == 1);
 555        if (recursing) {
 556                warning(_("recursive delta detected for object %s"),
 557                        oid_to_hex(&e->idx.oid));
 558                return WRITE_ONE_RECURSIVE;
 559        } else if (e->idx.offset || e->preferred_base) {
 560                /* offset is non zero if object is written already. */
 561                return WRITE_ONE_SKIP;
 562        }
 563
 564        /* if we are deltified, write out base object first. */
 565        if (DELTA(e)) {
 566                e->idx.offset = 1; /* now recurse */
 567                switch (write_one(f, DELTA(e), offset)) {
 568                case WRITE_ONE_RECURSIVE:
 569                        /* we cannot depend on this one */
 570                        SET_DELTA(e, NULL);
 571                        break;
 572                default:
 573                        break;
 574                case WRITE_ONE_BREAK:
 575                        e->idx.offset = recursing;
 576                        return WRITE_ONE_BREAK;
 577                }
 578        }
 579
 580        e->idx.offset = *offset;
 581        size = write_object(f, e, *offset);
 582        if (!size) {
 583                e->idx.offset = recursing;
 584                return WRITE_ONE_BREAK;
 585        }
 586        written_list[nr_written++] = &e->idx;
 587
 588        /* make sure off_t is sufficiently large not to wrap */
 589        if (signed_add_overflows(*offset, size))
 590                die(_("pack too large for current definition of off_t"));
 591        *offset += size;
 592        return WRITE_ONE_WRITTEN;
 593}
 594
 595static int mark_tagged(const char *path, const struct object_id *oid, int flag,
 596                       void *cb_data)
 597{
 598        struct object_id peeled;
 599        struct object_entry *entry = packlist_find(&to_pack, oid->hash, NULL);
 600
 601        if (entry)
 602                entry->tagged = 1;
 603        if (!peel_ref(path, &peeled)) {
 604                entry = packlist_find(&to_pack, peeled.hash, NULL);
 605                if (entry)
 606                        entry->tagged = 1;
 607        }
 608        return 0;
 609}
 610
 611static inline void add_to_write_order(struct object_entry **wo,
 612                               unsigned int *endp,
 613                               struct object_entry *e)
 614{
 615        if (e->filled)
 616                return;
 617        wo[(*endp)++] = e;
 618        e->filled = 1;
 619}
 620
 621static void add_descendants_to_write_order(struct object_entry **wo,
 622                                           unsigned int *endp,
 623                                           struct object_entry *e)
 624{
 625        int add_to_order = 1;
 626        while (e) {
 627                if (add_to_order) {
 628                        struct object_entry *s;
 629                        /* add this node... */
 630                        add_to_write_order(wo, endp, e);
 631                        /* all its siblings... */
 632                        for (s = DELTA_SIBLING(e); s; s = DELTA_SIBLING(s)) {
 633                                add_to_write_order(wo, endp, s);
 634                        }
 635                }
 636                /* drop down a level to add left subtree nodes if possible */
 637                if (DELTA_CHILD(e)) {
 638                        add_to_order = 1;
 639                        e = DELTA_CHILD(e);
 640                } else {
 641                        add_to_order = 0;
 642                        /* our sibling might have some children, it is next */
 643                        if (DELTA_SIBLING(e)) {
 644                                e = DELTA_SIBLING(e);
 645                                continue;
 646                        }
 647                        /* go back to our parent node */
 648                        e = DELTA(e);
 649                        while (e && !DELTA_SIBLING(e)) {
 650                                /* we're on the right side of a subtree, keep
 651                                 * going up until we can go right again */
 652                                e = DELTA(e);
 653                        }
 654                        if (!e) {
 655                                /* done- we hit our original root node */
 656                                return;
 657                        }
 658                        /* pass it off to sibling at this level */
 659                        e = DELTA_SIBLING(e);
 660                }
 661        };
 662}
 663
 664static void add_family_to_write_order(struct object_entry **wo,
 665                                      unsigned int *endp,
 666                                      struct object_entry *e)
 667{
 668        struct object_entry *root;
 669
 670        for (root = e; DELTA(root); root = DELTA(root))
 671                ; /* nothing */
 672        add_descendants_to_write_order(wo, endp, root);
 673}
 674
 675static struct object_entry **compute_write_order(void)
 676{
 677        unsigned int i, wo_end, last_untagged;
 678
 679        struct object_entry **wo;
 680        struct object_entry *objects = to_pack.objects;
 681
 682        for (i = 0; i < to_pack.nr_objects; i++) {
 683                objects[i].tagged = 0;
 684                objects[i].filled = 0;
 685                SET_DELTA_CHILD(&objects[i], NULL);
 686                SET_DELTA_SIBLING(&objects[i], NULL);
 687        }
 688
 689        /*
 690         * Fully connect delta_child/delta_sibling network.
 691         * Make sure delta_sibling is sorted in the original
 692         * recency order.
 693         */
 694        for (i = to_pack.nr_objects; i > 0;) {
 695                struct object_entry *e = &objects[--i];
 696                if (!DELTA(e))
 697                        continue;
 698                /* Mark me as the first child */
 699                e->delta_sibling_idx = DELTA(e)->delta_child_idx;
 700                SET_DELTA_CHILD(DELTA(e), e);
 701        }
 702
 703        /*
 704         * Mark objects that are at the tip of tags.
 705         */
 706        for_each_tag_ref(mark_tagged, NULL);
 707
 708        /*
 709         * Give the objects in the original recency order until
 710         * we see a tagged tip.
 711         */
 712        ALLOC_ARRAY(wo, to_pack.nr_objects);
 713        for (i = wo_end = 0; i < to_pack.nr_objects; i++) {
 714                if (objects[i].tagged)
 715                        break;
 716                add_to_write_order(wo, &wo_end, &objects[i]);
 717        }
 718        last_untagged = i;
 719
 720        /*
 721         * Then fill all the tagged tips.
 722         */
 723        for (; i < to_pack.nr_objects; i++) {
 724                if (objects[i].tagged)
 725                        add_to_write_order(wo, &wo_end, &objects[i]);
 726        }
 727
 728        /*
 729         * And then all remaining commits and tags.
 730         */
 731        for (i = last_untagged; i < to_pack.nr_objects; i++) {
 732                if (oe_type(&objects[i]) != OBJ_COMMIT &&
 733                    oe_type(&objects[i]) != OBJ_TAG)
 734                        continue;
 735                add_to_write_order(wo, &wo_end, &objects[i]);
 736        }
 737
 738        /*
 739         * And then all the trees.
 740         */
 741        for (i = last_untagged; i < to_pack.nr_objects; i++) {
 742                if (oe_type(&objects[i]) != OBJ_TREE)
 743                        continue;
 744                add_to_write_order(wo, &wo_end, &objects[i]);
 745        }
 746
 747        /*
 748         * Finally all the rest in really tight order
 749         */
 750        for (i = last_untagged; i < to_pack.nr_objects; i++) {
 751                if (!objects[i].filled)
 752                        add_family_to_write_order(wo, &wo_end, &objects[i]);
 753        }
 754
 755        if (wo_end != to_pack.nr_objects)
 756                die(_("ordered %u objects, expected %"PRIu32),
 757                    wo_end, to_pack.nr_objects);
 758
 759        return wo;
 760}
 761
 762static off_t write_reused_pack(struct hashfile *f)
 763{
 764        unsigned char buffer[8192];
 765        off_t to_write, total;
 766        int fd;
 767
 768        if (!is_pack_valid(reuse_packfile))
 769                die(_("packfile is invalid: %s"), reuse_packfile->pack_name);
 770
 771        fd = git_open(reuse_packfile->pack_name);
 772        if (fd < 0)
 773                die_errno(_("unable to open packfile for reuse: %s"),
 774                          reuse_packfile->pack_name);
 775
 776        if (lseek(fd, sizeof(struct pack_header), SEEK_SET) == -1)
 777                die_errno(_("unable to seek in reused packfile"));
 778
 779        if (reuse_packfile_offset < 0)
 780                reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
 781
 782        total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 783
 784        while (to_write) {
 785                int read_pack = xread(fd, buffer, sizeof(buffer));
 786
 787                if (read_pack <= 0)
 788                        die_errno(_("unable to read from reused packfile"));
 789
 790                if (read_pack > to_write)
 791                        read_pack = to_write;
 792
 793                hashwrite(f, buffer, read_pack);
 794                to_write -= read_pack;
 795
 796                /*
 797                 * We don't know the actual number of objects written,
 798                 * only how many bytes written, how many bytes total, and
 799                 * how many objects total. So we can fake it by pretending all
 800                 * objects we are writing are the same size. This gives us a
 801                 * smooth progress meter, and at the end it matches the true
 802                 * answer.
 803                 */
 804                written = reuse_packfile_objects *
 805                                (((double)(total - to_write)) / total);
 806                display_progress(progress_state, written);
 807        }
 808
 809        close(fd);
 810        written = reuse_packfile_objects;
 811        display_progress(progress_state, written);
 812        return reuse_packfile_offset - sizeof(struct pack_header);
 813}
 814
 815static const char no_split_warning[] = N_(
 816"disabling bitmap writing, packs are split due to pack.packSizeLimit"
 817);
 818
 819static void write_pack_file(void)
 820{
 821        uint32_t i = 0, j;
 822        struct hashfile *f;
 823        off_t offset;
 824        uint32_t nr_remaining = nr_result;
 825        time_t last_mtime = 0;
 826        struct object_entry **write_order;
 827
 828        if (progress > pack_to_stdout)
 829                progress_state = start_progress(_("Writing objects"), nr_result);
 830        ALLOC_ARRAY(written_list, to_pack.nr_objects);
 831        write_order = compute_write_order();
 832
 833        do {
 834                struct object_id oid;
 835                char *pack_tmp_name = NULL;
 836
 837                if (pack_to_stdout)
 838                        f = hashfd_throughput(1, "<stdout>", progress_state);
 839                else
 840                        f = create_tmp_packfile(&pack_tmp_name);
 841
 842                offset = write_pack_header(f, nr_remaining);
 843
 844                if (reuse_packfile) {
 845                        off_t packfile_size;
 846                        assert(pack_to_stdout);
 847
 848                        packfile_size = write_reused_pack(f);
 849                        offset += packfile_size;
 850                }
 851
 852                nr_written = 0;
 853                for (; i < to_pack.nr_objects; i++) {
 854                        struct object_entry *e = write_order[i];
 855                        if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 856                                break;
 857                        display_progress(progress_state, written);
 858                }
 859
 860                /*
 861                 * Did we write the wrong # entries in the header?
 862                 * If so, rewrite it like in fast-import
 863                 */
 864                if (pack_to_stdout) {
 865                        finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_CLOSE);
 866                } else if (nr_written == nr_remaining) {
 867                        finalize_hashfile(f, oid.hash, CSUM_HASH_IN_STREAM | CSUM_FSYNC | CSUM_CLOSE);
 868                } else {
 869                        int fd = finalize_hashfile(f, oid.hash, 0);
 870                        fixup_pack_header_footer(fd, oid.hash, pack_tmp_name,
 871                                                 nr_written, oid.hash, offset);
 872                        close(fd);
 873                        if (write_bitmap_index) {
 874                                warning(_(no_split_warning));
 875                                write_bitmap_index = 0;
 876                        }
 877                }
 878
 879                if (!pack_to_stdout) {
 880                        struct stat st;
 881                        struct strbuf tmpname = STRBUF_INIT;
 882
 883                        /*
 884                         * Packs are runtime accessed in their mtime
 885                         * order since newer packs are more likely to contain
 886                         * younger objects.  So if we are creating multiple
 887                         * packs then we should modify the mtime of later ones
 888                         * to preserve this property.
 889                         */
 890                        if (stat(pack_tmp_name, &st) < 0) {
 891                                warning_errno(_("failed to stat %s"), pack_tmp_name);
 892                        } else if (!last_mtime) {
 893                                last_mtime = st.st_mtime;
 894                        } else {
 895                                struct utimbuf utb;
 896                                utb.actime = st.st_atime;
 897                                utb.modtime = --last_mtime;
 898                                if (utime(pack_tmp_name, &utb) < 0)
 899                                        warning_errno(_("failed utime() on %s"), pack_tmp_name);
 900                        }
 901
 902                        strbuf_addf(&tmpname, "%s-", base_name);
 903
 904                        if (write_bitmap_index) {
 905                                bitmap_writer_set_checksum(oid.hash);
 906                                bitmap_writer_build_type_index(
 907                                        &to_pack, written_list, nr_written);
 908                        }
 909
 910                        finish_tmp_packfile(&tmpname, pack_tmp_name,
 911                                            written_list, nr_written,
 912                                            &pack_idx_opts, oid.hash);
 913
 914                        if (write_bitmap_index) {
 915                                strbuf_addf(&tmpname, "%s.bitmap", oid_to_hex(&oid));
 916
 917                                stop_progress(&progress_state);
 918
 919                                bitmap_writer_show_progress(progress);
 920                                bitmap_writer_reuse_bitmaps(&to_pack);
 921                                bitmap_writer_select_commits(indexed_commits, indexed_commits_nr, -1);
 922                                bitmap_writer_build(&to_pack);
 923                                bitmap_writer_finish(written_list, nr_written,
 924                                                     tmpname.buf, write_bitmap_options);
 925                                write_bitmap_index = 0;
 926                        }
 927
 928                        strbuf_release(&tmpname);
 929                        free(pack_tmp_name);
 930                        puts(oid_to_hex(&oid));
 931                }
 932
 933                /* mark written objects as written to previous pack */
 934                for (j = 0; j < nr_written; j++) {
 935                        written_list[j]->offset = (off_t)-1;
 936                }
 937                nr_remaining -= nr_written;
 938        } while (nr_remaining && i < to_pack.nr_objects);
 939
 940        free(written_list);
 941        free(write_order);
 942        stop_progress(&progress_state);
 943        if (written != nr_result)
 944                die(_("wrote %"PRIu32" objects while expecting %"PRIu32),
 945                    written, nr_result);
 946}
 947
 948static int no_try_delta(const char *path)
 949{
 950        static struct attr_check *check;
 951
 952        if (!check)
 953                check = attr_check_initl("delta", NULL);
 954        if (git_check_attr(&the_index, path, check))
 955                return 0;
 956        if (ATTR_FALSE(check->items[0].value))
 957                return 1;
 958        return 0;
 959}
 960
 961/*
 962 * When adding an object, check whether we have already added it
 963 * to our packing list. If so, we can skip. However, if we are
 964 * being asked to excludei t, but the previous mention was to include
 965 * it, make sure to adjust its flags and tweak our numbers accordingly.
 966 *
 967 * As an optimization, we pass out the index position where we would have
 968 * found the item, since that saves us from having to look it up again a
 969 * few lines later when we want to add the new entry.
 970 */
 971static int have_duplicate_entry(const struct object_id *oid,
 972                                int exclude,
 973                                uint32_t *index_pos)
 974{
 975        struct object_entry *entry;
 976
 977        entry = packlist_find(&to_pack, oid->hash, index_pos);
 978        if (!entry)
 979                return 0;
 980
 981        if (exclude) {
 982                if (!entry->preferred_base)
 983                        nr_result--;
 984                entry->preferred_base = 1;
 985        }
 986
 987        return 1;
 988}
 989
 990static int want_found_object(int exclude, struct packed_git *p)
 991{
 992        if (exclude)
 993                return 1;
 994        if (incremental)
 995                return 0;
 996
 997        /*
 998         * When asked to do --local (do not include an object that appears in a
 999         * pack we borrow from elsewhere) or --honor-pack-keep (do not include
1000         * an object that appears in a pack marked with .keep), finding a pack
1001         * that matches the criteria is sufficient for us to decide to omit it.
1002         * However, even if this pack does not satisfy the criteria, we need to
1003         * make sure no copy of this object appears in _any_ pack that makes us
1004         * to omit the object, so we need to check all the packs.
1005         *
1006         * We can however first check whether these options can possible matter;
1007         * if they do not matter we know we want the object in generated pack.
1008         * Otherwise, we signal "-1" at the end to tell the caller that we do
1009         * not know either way, and it needs to check more packs.
1010         */
1011        if (!ignore_packed_keep_on_disk &&
1012            !ignore_packed_keep_in_core &&
1013            (!local || !have_non_local_packs))
1014                return 1;
1015
1016        if (local && !p->pack_local)
1017                return 0;
1018        if (p->pack_local &&
1019            ((ignore_packed_keep_on_disk && p->pack_keep) ||
1020             (ignore_packed_keep_in_core && p->pack_keep_in_core)))
1021                return 0;
1022
1023        /* we don't know yet; keep looking for more packs */
1024        return -1;
1025}
1026
1027/*
1028 * Check whether we want the object in the pack (e.g., we do not want
1029 * objects found in non-local stores if the "--local" option was used).
1030 *
1031 * If the caller already knows an existing pack it wants to take the object
1032 * from, that is passed in *found_pack and *found_offset; otherwise this
1033 * function finds if there is any pack that has the object and returns the pack
1034 * and its offset in these variables.
1035 */
1036static int want_object_in_pack(const struct object_id *oid,
1037                               int exclude,
1038                               struct packed_git **found_pack,
1039                               off_t *found_offset)
1040{
1041        int want;
1042        struct list_head *pos;
1043
1044        if (!exclude && local && has_loose_object_nonlocal(oid))
1045                return 0;
1046
1047        /*
1048         * If we already know the pack object lives in, start checks from that
1049         * pack - in the usual case when neither --local was given nor .keep files
1050         * are present we will determine the answer right now.
1051         */
1052        if (*found_pack) {
1053                want = want_found_object(exclude, *found_pack);
1054                if (want != -1)
1055                        return want;
1056        }
1057        list_for_each(pos, get_packed_git_mru(the_repository)) {
1058                struct packed_git *p = list_entry(pos, struct packed_git, mru);
1059                off_t offset;
1060
1061                if (p == *found_pack)
1062                        offset = *found_offset;
1063                else
1064                        offset = find_pack_entry_one(oid->hash, p);
1065
1066                if (offset) {
1067                        if (!*found_pack) {
1068                                if (!is_pack_valid(p))
1069                                        continue;
1070                                *found_offset = offset;
1071                                *found_pack = p;
1072                        }
1073                        want = want_found_object(exclude, p);
1074                        if (!exclude && want > 0)
1075                                list_move(&p->mru,
1076                                          get_packed_git_mru(the_repository));
1077                        if (want != -1)
1078                                return want;
1079                }
1080        }
1081
1082        return 1;
1083}
1084
1085static void create_object_entry(const struct object_id *oid,
1086                                enum object_type type,
1087                                uint32_t hash,
1088                                int exclude,
1089                                int no_try_delta,
1090                                uint32_t index_pos,
1091                                struct packed_git *found_pack,
1092                                off_t found_offset)
1093{
1094        struct object_entry *entry;
1095
1096        entry = packlist_alloc(&to_pack, oid->hash, index_pos);
1097        entry->hash = hash;
1098        oe_set_type(entry, type);
1099        if (exclude)
1100                entry->preferred_base = 1;
1101        else
1102                nr_result++;
1103        if (found_pack) {
1104                oe_set_in_pack(&to_pack, entry, found_pack);
1105                entry->in_pack_offset = found_offset;
1106        }
1107
1108        entry->no_try_delta = no_try_delta;
1109}
1110
1111static const char no_closure_warning[] = N_(
1112"disabling bitmap writing, as some objects are not being packed"
1113);
1114
1115static int add_object_entry(const struct object_id *oid, enum object_type type,
1116                            const char *name, int exclude)
1117{
1118        struct packed_git *found_pack = NULL;
1119        off_t found_offset = 0;
1120        uint32_t index_pos;
1121
1122        display_progress(progress_state, ++nr_seen);
1123
1124        if (have_duplicate_entry(oid, exclude, &index_pos))
1125                return 0;
1126
1127        if (!want_object_in_pack(oid, exclude, &found_pack, &found_offset)) {
1128                /* The pack is missing an object, so it will not have closure */
1129                if (write_bitmap_index) {
1130                        warning(_(no_closure_warning));
1131                        write_bitmap_index = 0;
1132                }
1133                return 0;
1134        }
1135
1136        create_object_entry(oid, type, pack_name_hash(name),
1137                            exclude, name && no_try_delta(name),
1138                            index_pos, found_pack, found_offset);
1139        return 1;
1140}
1141
1142static int add_object_entry_from_bitmap(const struct object_id *oid,
1143                                        enum object_type type,
1144                                        int flags, uint32_t name_hash,
1145                                        struct packed_git *pack, off_t offset)
1146{
1147        uint32_t index_pos;
1148
1149        display_progress(progress_state, ++nr_seen);
1150
1151        if (have_duplicate_entry(oid, 0, &index_pos))
1152                return 0;
1153
1154        if (!want_object_in_pack(oid, 0, &pack, &offset))
1155                return 0;
1156
1157        create_object_entry(oid, type, name_hash, 0, 0, index_pos, pack, offset);
1158        return 1;
1159}
1160
1161struct pbase_tree_cache {
1162        struct object_id oid;
1163        int ref;
1164        int temporary;
1165        void *tree_data;
1166        unsigned long tree_size;
1167};
1168
1169static struct pbase_tree_cache *(pbase_tree_cache[256]);
1170static int pbase_tree_cache_ix(const struct object_id *oid)
1171{
1172        return oid->hash[0] % ARRAY_SIZE(pbase_tree_cache);
1173}
1174static int pbase_tree_cache_ix_incr(int ix)
1175{
1176        return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
1177}
1178
1179static struct pbase_tree {
1180        struct pbase_tree *next;
1181        /* This is a phony "cache" entry; we are not
1182         * going to evict it or find it through _get()
1183         * mechanism -- this is for the toplevel node that
1184         * would almost always change with any commit.
1185         */
1186        struct pbase_tree_cache pcache;
1187} *pbase_tree;
1188
1189static struct pbase_tree_cache *pbase_tree_get(const struct object_id *oid)
1190{
1191        struct pbase_tree_cache *ent, *nent;
1192        void *data;
1193        unsigned long size;
1194        enum object_type type;
1195        int neigh;
1196        int my_ix = pbase_tree_cache_ix(oid);
1197        int available_ix = -1;
1198
1199        /* pbase-tree-cache acts as a limited hashtable.
1200         * your object will be found at your index or within a few
1201         * slots after that slot if it is cached.
1202         */
1203        for (neigh = 0; neigh < 8; neigh++) {
1204                ent = pbase_tree_cache[my_ix];
1205                if (ent && !oidcmp(&ent->oid, oid)) {
1206                        ent->ref++;
1207                        return ent;
1208                }
1209                else if (((available_ix < 0) && (!ent || !ent->ref)) ||
1210                         ((0 <= available_ix) &&
1211                          (!ent && pbase_tree_cache[available_ix])))
1212                        available_ix = my_ix;
1213                if (!ent)
1214                        break;
1215                my_ix = pbase_tree_cache_ix_incr(my_ix);
1216        }
1217
1218        /* Did not find one.  Either we got a bogus request or
1219         * we need to read and perhaps cache.
1220         */
1221        data = read_object_file(oid, &type, &size);
1222        if (!data)
1223                return NULL;
1224        if (type != OBJ_TREE) {
1225                free(data);
1226                return NULL;
1227        }
1228
1229        /* We need to either cache or return a throwaway copy */
1230
1231        if (available_ix < 0)
1232                ent = NULL;
1233        else {
1234                ent = pbase_tree_cache[available_ix];
1235                my_ix = available_ix;
1236        }
1237
1238        if (!ent) {
1239                nent = xmalloc(sizeof(*nent));
1240                nent->temporary = (available_ix < 0);
1241        }
1242        else {
1243                /* evict and reuse */
1244                free(ent->tree_data);
1245                nent = ent;
1246        }
1247        oidcpy(&nent->oid, oid);
1248        nent->tree_data = data;
1249        nent->tree_size = size;
1250        nent->ref = 1;
1251        if (!nent->temporary)
1252                pbase_tree_cache[my_ix] = nent;
1253        return nent;
1254}
1255
1256static void pbase_tree_put(struct pbase_tree_cache *cache)
1257{
1258        if (!cache->temporary) {
1259                cache->ref--;
1260                return;
1261        }
1262        free(cache->tree_data);
1263        free(cache);
1264}
1265
1266static int name_cmp_len(const char *name)
1267{
1268        int i;
1269        for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1270                ;
1271        return i;
1272}
1273
1274static void add_pbase_object(struct tree_desc *tree,
1275                             const char *name,
1276                             int cmplen,
1277                             const char *fullname)
1278{
1279        struct name_entry entry;
1280        int cmp;
1281
1282        while (tree_entry(tree,&entry)) {
1283                if (S_ISGITLINK(entry.mode))
1284                        continue;
1285                cmp = tree_entry_len(&entry) != cmplen ? 1 :
1286                      memcmp(name, entry.path, cmplen);
1287                if (cmp > 0)
1288                        continue;
1289                if (cmp < 0)
1290                        return;
1291                if (name[cmplen] != '/') {
1292                        add_object_entry(entry.oid,
1293                                         object_type(entry.mode),
1294                                         fullname, 1);
1295                        return;
1296                }
1297                if (S_ISDIR(entry.mode)) {
1298                        struct tree_desc sub;
1299                        struct pbase_tree_cache *tree;
1300                        const char *down = name+cmplen+1;
1301                        int downlen = name_cmp_len(down);
1302
1303                        tree = pbase_tree_get(entry.oid);
1304                        if (!tree)
1305                                return;
1306                        init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1307
1308                        add_pbase_object(&sub, down, downlen, fullname);
1309                        pbase_tree_put(tree);
1310                }
1311        }
1312}
1313
1314static unsigned *done_pbase_paths;
1315static int done_pbase_paths_num;
1316static int done_pbase_paths_alloc;
1317static int done_pbase_path_pos(unsigned hash)
1318{
1319        int lo = 0;
1320        int hi = done_pbase_paths_num;
1321        while (lo < hi) {
1322                int mi = lo + (hi - lo) / 2;
1323                if (done_pbase_paths[mi] == hash)
1324                        return mi;
1325                if (done_pbase_paths[mi] < hash)
1326                        hi = mi;
1327                else
1328                        lo = mi + 1;
1329        }
1330        return -lo-1;
1331}
1332
1333static int check_pbase_path(unsigned hash)
1334{
1335        int pos = done_pbase_path_pos(hash);
1336        if (0 <= pos)
1337                return 1;
1338        pos = -pos - 1;
1339        ALLOC_GROW(done_pbase_paths,
1340                   done_pbase_paths_num + 1,
1341                   done_pbase_paths_alloc);
1342        done_pbase_paths_num++;
1343        if (pos < done_pbase_paths_num)
1344                MOVE_ARRAY(done_pbase_paths + pos + 1, done_pbase_paths + pos,
1345                           done_pbase_paths_num - pos - 1);
1346        done_pbase_paths[pos] = hash;
1347        return 0;
1348}
1349
1350static void add_preferred_base_object(const char *name)
1351{
1352        struct pbase_tree *it;
1353        int cmplen;
1354        unsigned hash = pack_name_hash(name);
1355
1356        if (!num_preferred_base || check_pbase_path(hash))
1357                return;
1358
1359        cmplen = name_cmp_len(name);
1360        for (it = pbase_tree; it; it = it->next) {
1361                if (cmplen == 0) {
1362                        add_object_entry(&it->pcache.oid, OBJ_TREE, NULL, 1);
1363                }
1364                else {
1365                        struct tree_desc tree;
1366                        init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1367                        add_pbase_object(&tree, name, cmplen, name);
1368                }
1369        }
1370}
1371
1372static void add_preferred_base(struct object_id *oid)
1373{
1374        struct pbase_tree *it;
1375        void *data;
1376        unsigned long size;
1377        struct object_id tree_oid;
1378
1379        if (window <= num_preferred_base++)
1380                return;
1381
1382        data = read_object_with_reference(oid, tree_type, &size, &tree_oid);
1383        if (!data)
1384                return;
1385
1386        for (it = pbase_tree; it; it = it->next) {
1387                if (!oidcmp(&it->pcache.oid, &tree_oid)) {
1388                        free(data);
1389                        return;
1390                }
1391        }
1392
1393        it = xcalloc(1, sizeof(*it));
1394        it->next = pbase_tree;
1395        pbase_tree = it;
1396
1397        oidcpy(&it->pcache.oid, &tree_oid);
1398        it->pcache.tree_data = data;
1399        it->pcache.tree_size = size;
1400}
1401
1402static void cleanup_preferred_base(void)
1403{
1404        struct pbase_tree *it;
1405        unsigned i;
1406
1407        it = pbase_tree;
1408        pbase_tree = NULL;
1409        while (it) {
1410                struct pbase_tree *tmp = it;
1411                it = tmp->next;
1412                free(tmp->pcache.tree_data);
1413                free(tmp);
1414        }
1415
1416        for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1417                if (!pbase_tree_cache[i])
1418                        continue;
1419                free(pbase_tree_cache[i]->tree_data);
1420                FREE_AND_NULL(pbase_tree_cache[i]);
1421        }
1422
1423        FREE_AND_NULL(done_pbase_paths);
1424        done_pbase_paths_num = done_pbase_paths_alloc = 0;
1425}
1426
1427static void check_object(struct object_entry *entry)
1428{
1429        unsigned long canonical_size;
1430
1431        if (IN_PACK(entry)) {
1432                struct packed_git *p = IN_PACK(entry);
1433                struct pack_window *w_curs = NULL;
1434                const unsigned char *base_ref = NULL;
1435                struct object_entry *base_entry;
1436                unsigned long used, used_0;
1437                unsigned long avail;
1438                off_t ofs;
1439                unsigned char *buf, c;
1440                enum object_type type;
1441                unsigned long in_pack_size;
1442
1443                buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1444
1445                /*
1446                 * We want in_pack_type even if we do not reuse delta
1447                 * since non-delta representations could still be reused.
1448                 */
1449                used = unpack_object_header_buffer(buf, avail,
1450                                                   &type,
1451                                                   &in_pack_size);
1452                if (used == 0)
1453                        goto give_up;
1454
1455                if (type < 0)
1456                        BUG("invalid type %d", type);
1457                entry->in_pack_type = type;
1458
1459                /*
1460                 * Determine if this is a delta and if so whether we can
1461                 * reuse it or not.  Otherwise let's find out as cheaply as
1462                 * possible what the actual type and size for this object is.
1463                 */
1464                switch (entry->in_pack_type) {
1465                default:
1466                        /* Not a delta hence we've already got all we need. */
1467                        oe_set_type(entry, entry->in_pack_type);
1468                        SET_SIZE(entry, in_pack_size);
1469                        entry->in_pack_header_size = used;
1470                        if (oe_type(entry) < OBJ_COMMIT || oe_type(entry) > OBJ_BLOB)
1471                                goto give_up;
1472                        unuse_pack(&w_curs);
1473                        return;
1474                case OBJ_REF_DELTA:
1475                        if (reuse_delta && !entry->preferred_base)
1476                                base_ref = use_pack(p, &w_curs,
1477                                                entry->in_pack_offset + used, NULL);
1478                        entry->in_pack_header_size = used + the_hash_algo->rawsz;
1479                        break;
1480                case OBJ_OFS_DELTA:
1481                        buf = use_pack(p, &w_curs,
1482                                       entry->in_pack_offset + used, NULL);
1483                        used_0 = 0;
1484                        c = buf[used_0++];
1485                        ofs = c & 127;
1486                        while (c & 128) {
1487                                ofs += 1;
1488                                if (!ofs || MSB(ofs, 7)) {
1489                                        error(_("delta base offset overflow in pack for %s"),
1490                                              oid_to_hex(&entry->idx.oid));
1491                                        goto give_up;
1492                                }
1493                                c = buf[used_0++];
1494                                ofs = (ofs << 7) + (c & 127);
1495                        }
1496                        ofs = entry->in_pack_offset - ofs;
1497                        if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1498                                error(_("delta base offset out of bound for %s"),
1499                                      oid_to_hex(&entry->idx.oid));
1500                                goto give_up;
1501                        }
1502                        if (reuse_delta && !entry->preferred_base) {
1503                                struct revindex_entry *revidx;
1504                                revidx = find_pack_revindex(p, ofs);
1505                                if (!revidx)
1506                                        goto give_up;
1507                                base_ref = nth_packed_object_sha1(p, revidx->nr);
1508                        }
1509                        entry->in_pack_header_size = used + used_0;
1510                        break;
1511                }
1512
1513                if (base_ref && (base_entry = packlist_find(&to_pack, base_ref, NULL))) {
1514                        /*
1515                         * If base_ref was set above that means we wish to
1516                         * reuse delta data, and we even found that base
1517                         * in the list of objects we want to pack. Goodie!
1518                         *
1519                         * Depth value does not matter - find_deltas() will
1520                         * never consider reused delta as the base object to
1521                         * deltify other objects against, in order to avoid
1522                         * circular deltas.
1523                         */
1524                        oe_set_type(entry, entry->in_pack_type);
1525                        SET_SIZE(entry, in_pack_size); /* delta size */
1526                        SET_DELTA(entry, base_entry);
1527                        SET_DELTA_SIZE(entry, in_pack_size);
1528                        entry->delta_sibling_idx = base_entry->delta_child_idx;
1529                        SET_DELTA_CHILD(base_entry, entry);
1530                        unuse_pack(&w_curs);
1531                        return;
1532                }
1533
1534                if (oe_type(entry)) {
1535                        off_t delta_pos;
1536
1537                        /*
1538                         * This must be a delta and we already know what the
1539                         * final object type is.  Let's extract the actual
1540                         * object size from the delta header.
1541                         */
1542                        delta_pos = entry->in_pack_offset + entry->in_pack_header_size;
1543                        canonical_size = get_size_from_delta(p, &w_curs, delta_pos);
1544                        if (canonical_size == 0)
1545                                goto give_up;
1546                        SET_SIZE(entry, canonical_size);
1547                        unuse_pack(&w_curs);
1548                        return;
1549                }
1550
1551                /*
1552                 * No choice but to fall back to the recursive delta walk
1553                 * with sha1_object_info() to find about the object type
1554                 * at this point...
1555                 */
1556                give_up:
1557                unuse_pack(&w_curs);
1558        }
1559
1560        oe_set_type(entry,
1561                    oid_object_info(the_repository, &entry->idx.oid, &canonical_size));
1562        if (entry->type_valid) {
1563                SET_SIZE(entry, canonical_size);
1564        } else {
1565                /*
1566                 * Bad object type is checked in prepare_pack().  This is
1567                 * to permit a missing preferred base object to be ignored
1568                 * as a preferred base.  Doing so can result in a larger
1569                 * pack file, but the transfer will still take place.
1570                 */
1571        }
1572}
1573
1574static int pack_offset_sort(const void *_a, const void *_b)
1575{
1576        const struct object_entry *a = *(struct object_entry **)_a;
1577        const struct object_entry *b = *(struct object_entry **)_b;
1578        const struct packed_git *a_in_pack = IN_PACK(a);
1579        const struct packed_git *b_in_pack = IN_PACK(b);
1580
1581        /* avoid filesystem trashing with loose objects */
1582        if (!a_in_pack && !b_in_pack)
1583                return oidcmp(&a->idx.oid, &b->idx.oid);
1584
1585        if (a_in_pack < b_in_pack)
1586                return -1;
1587        if (a_in_pack > b_in_pack)
1588                return 1;
1589        return a->in_pack_offset < b->in_pack_offset ? -1 :
1590                        (a->in_pack_offset > b->in_pack_offset);
1591}
1592
1593/*
1594 * Drop an on-disk delta we were planning to reuse. Naively, this would
1595 * just involve blanking out the "delta" field, but we have to deal
1596 * with some extra book-keeping:
1597 *
1598 *   1. Removing ourselves from the delta_sibling linked list.
1599 *
1600 *   2. Updating our size/type to the non-delta representation. These were
1601 *      either not recorded initially (size) or overwritten with the delta type
1602 *      (type) when check_object() decided to reuse the delta.
1603 *
1604 *   3. Resetting our delta depth, as we are now a base object.
1605 */
1606static void drop_reused_delta(struct object_entry *entry)
1607{
1608        unsigned *idx = &to_pack.objects[entry->delta_idx - 1].delta_child_idx;
1609        struct object_info oi = OBJECT_INFO_INIT;
1610        enum object_type type;
1611        unsigned long size;
1612
1613        while (*idx) {
1614                struct object_entry *oe = &to_pack.objects[*idx - 1];
1615
1616                if (oe == entry)
1617                        *idx = oe->delta_sibling_idx;
1618                else
1619                        idx = &oe->delta_sibling_idx;
1620        }
1621        SET_DELTA(entry, NULL);
1622        entry->depth = 0;
1623
1624        oi.sizep = &size;
1625        oi.typep = &type;
1626        if (packed_object_info(the_repository, IN_PACK(entry), entry->in_pack_offset, &oi) < 0) {
1627                /*
1628                 * We failed to get the info from this pack for some reason;
1629                 * fall back to sha1_object_info, which may find another copy.
1630                 * And if that fails, the error will be recorded in oe_type(entry)
1631                 * and dealt with in prepare_pack().
1632                 */
1633                oe_set_type(entry,
1634                            oid_object_info(the_repository, &entry->idx.oid, &size));
1635        } else {
1636                oe_set_type(entry, type);
1637        }
1638        SET_SIZE(entry, size);
1639}
1640
1641/*
1642 * Follow the chain of deltas from this entry onward, throwing away any links
1643 * that cause us to hit a cycle (as determined by the DFS state flags in
1644 * the entries).
1645 *
1646 * We also detect too-long reused chains that would violate our --depth
1647 * limit.
1648 */
1649static void break_delta_chains(struct object_entry *entry)
1650{
1651        /*
1652         * The actual depth of each object we will write is stored as an int,
1653         * as it cannot exceed our int "depth" limit. But before we break
1654         * changes based no that limit, we may potentially go as deep as the
1655         * number of objects, which is elsewhere bounded to a uint32_t.
1656         */
1657        uint32_t total_depth;
1658        struct object_entry *cur, *next;
1659
1660        for (cur = entry, total_depth = 0;
1661             cur;
1662             cur = DELTA(cur), total_depth++) {
1663                if (cur->dfs_state == DFS_DONE) {
1664                        /*
1665                         * We've already seen this object and know it isn't
1666                         * part of a cycle. We do need to append its depth
1667                         * to our count.
1668                         */
1669                        total_depth += cur->depth;
1670                        break;
1671                }
1672
1673                /*
1674                 * We break cycles before looping, so an ACTIVE state (or any
1675                 * other cruft which made its way into the state variable)
1676                 * is a bug.
1677                 */
1678                if (cur->dfs_state != DFS_NONE)
1679                        BUG("confusing delta dfs state in first pass: %d",
1680                            cur->dfs_state);
1681
1682                /*
1683                 * Now we know this is the first time we've seen the object. If
1684                 * it's not a delta, we're done traversing, but we'll mark it
1685                 * done to save time on future traversals.
1686                 */
1687                if (!DELTA(cur)) {
1688                        cur->dfs_state = DFS_DONE;
1689                        break;
1690                }
1691
1692                /*
1693                 * Mark ourselves as active and see if the next step causes
1694                 * us to cycle to another active object. It's important to do
1695                 * this _before_ we loop, because it impacts where we make the
1696                 * cut, and thus how our total_depth counter works.
1697                 * E.g., We may see a partial loop like:
1698                 *
1699                 *   A -> B -> C -> D -> B
1700                 *
1701                 * Cutting B->C breaks the cycle. But now the depth of A is
1702                 * only 1, and our total_depth counter is at 3. The size of the
1703                 * error is always one less than the size of the cycle we
1704                 * broke. Commits C and D were "lost" from A's chain.
1705                 *
1706                 * If we instead cut D->B, then the depth of A is correct at 3.
1707                 * We keep all commits in the chain that we examined.
1708                 */
1709                cur->dfs_state = DFS_ACTIVE;
1710                if (DELTA(cur)->dfs_state == DFS_ACTIVE) {
1711                        drop_reused_delta(cur);
1712                        cur->dfs_state = DFS_DONE;
1713                        break;
1714                }
1715        }
1716
1717        /*
1718         * And now that we've gone all the way to the bottom of the chain, we
1719         * need to clear the active flags and set the depth fields as
1720         * appropriate. Unlike the loop above, which can quit when it drops a
1721         * delta, we need to keep going to look for more depth cuts. So we need
1722         * an extra "next" pointer to keep going after we reset cur->delta.
1723         */
1724        for (cur = entry; cur; cur = next) {
1725                next = DELTA(cur);
1726
1727                /*
1728                 * We should have a chain of zero or more ACTIVE states down to
1729                 * a final DONE. We can quit after the DONE, because either it
1730                 * has no bases, or we've already handled them in a previous
1731                 * call.
1732                 */
1733                if (cur->dfs_state == DFS_DONE)
1734                        break;
1735                else if (cur->dfs_state != DFS_ACTIVE)
1736                        BUG("confusing delta dfs state in second pass: %d",
1737                            cur->dfs_state);
1738
1739                /*
1740                 * If the total_depth is more than depth, then we need to snip
1741                 * the chain into two or more smaller chains that don't exceed
1742                 * the maximum depth. Most of the resulting chains will contain
1743                 * (depth + 1) entries (i.e., depth deltas plus one base), and
1744                 * the last chain (i.e., the one containing entry) will contain
1745                 * whatever entries are left over, namely
1746                 * (total_depth % (depth + 1)) of them.
1747                 *
1748                 * Since we are iterating towards decreasing depth, we need to
1749                 * decrement total_depth as we go, and we need to write to the
1750                 * entry what its final depth will be after all of the
1751                 * snipping. Since we're snipping into chains of length (depth
1752                 * + 1) entries, the final depth of an entry will be its
1753                 * original depth modulo (depth + 1). Any time we encounter an
1754                 * entry whose final depth is supposed to be zero, we snip it
1755                 * from its delta base, thereby making it so.
1756                 */
1757                cur->depth = (total_depth--) % (depth + 1);
1758                if (!cur->depth)
1759                        drop_reused_delta(cur);
1760
1761                cur->dfs_state = DFS_DONE;
1762        }
1763}
1764
1765static void get_object_details(void)
1766{
1767        uint32_t i;
1768        struct object_entry **sorted_by_offset;
1769
1770        if (progress)
1771                progress_state = start_progress(_("Counting objects"),
1772                                                to_pack.nr_objects);
1773
1774        sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
1775        for (i = 0; i < to_pack.nr_objects; i++)
1776                sorted_by_offset[i] = to_pack.objects + i;
1777        QSORT(sorted_by_offset, to_pack.nr_objects, pack_offset_sort);
1778
1779        for (i = 0; i < to_pack.nr_objects; i++) {
1780                struct object_entry *entry = sorted_by_offset[i];
1781                check_object(entry);
1782                if (entry->type_valid &&
1783                    oe_size_greater_than(&to_pack, entry, big_file_threshold))
1784                        entry->no_try_delta = 1;
1785                display_progress(progress_state, i + 1);
1786        }
1787        stop_progress(&progress_state);
1788
1789        /*
1790         * This must happen in a second pass, since we rely on the delta
1791         * information for the whole list being completed.
1792         */
1793        for (i = 0; i < to_pack.nr_objects; i++)
1794                break_delta_chains(&to_pack.objects[i]);
1795
1796        free(sorted_by_offset);
1797}
1798
1799/*
1800 * We search for deltas in a list sorted by type, by filename hash, and then
1801 * by size, so that we see progressively smaller and smaller files.
1802 * That's because we prefer deltas to be from the bigger file
1803 * to the smaller -- deletes are potentially cheaper, but perhaps
1804 * more importantly, the bigger file is likely the more recent
1805 * one.  The deepest deltas are therefore the oldest objects which are
1806 * less susceptible to be accessed often.
1807 */
1808static int type_size_sort(const void *_a, const void *_b)
1809{
1810        const struct object_entry *a = *(struct object_entry **)_a;
1811        const struct object_entry *b = *(struct object_entry **)_b;
1812        enum object_type a_type = oe_type(a);
1813        enum object_type b_type = oe_type(b);
1814        unsigned long a_size = SIZE(a);
1815        unsigned long b_size = SIZE(b);
1816
1817        if (a_type > b_type)
1818                return -1;
1819        if (a_type < b_type)
1820                return 1;
1821        if (a->hash > b->hash)
1822                return -1;
1823        if (a->hash < b->hash)
1824                return 1;
1825        if (a->preferred_base > b->preferred_base)
1826                return -1;
1827        if (a->preferred_base < b->preferred_base)
1828                return 1;
1829        if (a_size > b_size)
1830                return -1;
1831        if (a_size < b_size)
1832                return 1;
1833        return a < b ? -1 : (a > b);  /* newest first */
1834}
1835
1836struct unpacked {
1837        struct object_entry *entry;
1838        void *data;
1839        struct delta_index *index;
1840        unsigned depth;
1841};
1842
1843static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1844                           unsigned long delta_size)
1845{
1846        if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1847                return 0;
1848
1849        if (delta_size < cache_max_small_delta_size)
1850                return 1;
1851
1852        /* cache delta, if objects are large enough compared to delta size */
1853        if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1854                return 1;
1855
1856        return 0;
1857}
1858
1859#ifndef NO_PTHREADS
1860
1861/* Protect access to object database */
1862static pthread_mutex_t read_mutex;
1863#define read_lock()             pthread_mutex_lock(&read_mutex)
1864#define read_unlock()           pthread_mutex_unlock(&read_mutex)
1865
1866/* Protect delta_cache_size */
1867static pthread_mutex_t cache_mutex;
1868#define cache_lock()            pthread_mutex_lock(&cache_mutex)
1869#define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1870
1871/*
1872 * Protect object list partitioning (e.g. struct thread_param) and
1873 * progress_state
1874 */
1875static pthread_mutex_t progress_mutex;
1876#define progress_lock()         pthread_mutex_lock(&progress_mutex)
1877#define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1878
1879/*
1880 * Access to struct object_entry is unprotected since each thread owns
1881 * a portion of the main object list. Just don't access object entries
1882 * ahead in the list because they can be stolen and would need
1883 * progress_mutex for protection.
1884 */
1885#else
1886
1887#define read_lock()             (void)0
1888#define read_unlock()           (void)0
1889#define cache_lock()            (void)0
1890#define cache_unlock()          (void)0
1891#define progress_lock()         (void)0
1892#define progress_unlock()       (void)0
1893
1894#endif
1895
1896/*
1897 * Return the size of the object without doing any delta
1898 * reconstruction (so non-deltas are true object sizes, but deltas
1899 * return the size of the delta data).
1900 */
1901unsigned long oe_get_size_slow(struct packing_data *pack,
1902                               const struct object_entry *e)
1903{
1904        struct packed_git *p;
1905        struct pack_window *w_curs;
1906        unsigned char *buf;
1907        enum object_type type;
1908        unsigned long used, avail, size;
1909
1910        if (e->type_ != OBJ_OFS_DELTA && e->type_ != OBJ_REF_DELTA) {
1911                read_lock();
1912                if (oid_object_info(the_repository, &e->idx.oid, &size) < 0)
1913                        die(_("unable to get size of %s"),
1914                            oid_to_hex(&e->idx.oid));
1915                read_unlock();
1916                return size;
1917        }
1918
1919        p = oe_in_pack(pack, e);
1920        if (!p)
1921                BUG("when e->type is a delta, it must belong to a pack");
1922
1923        read_lock();
1924        w_curs = NULL;
1925        buf = use_pack(p, &w_curs, e->in_pack_offset, &avail);
1926        used = unpack_object_header_buffer(buf, avail, &type, &size);
1927        if (used == 0)
1928                die(_("unable to parse object header of %s"),
1929                    oid_to_hex(&e->idx.oid));
1930
1931        unuse_pack(&w_curs);
1932        read_unlock();
1933        return size;
1934}
1935
1936static int try_delta(struct unpacked *trg, struct unpacked *src,
1937                     unsigned max_depth, unsigned long *mem_usage)
1938{
1939        struct object_entry *trg_entry = trg->entry;
1940        struct object_entry *src_entry = src->entry;
1941        unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1942        unsigned ref_depth;
1943        enum object_type type;
1944        void *delta_buf;
1945
1946        /* Don't bother doing diffs between different types */
1947        if (oe_type(trg_entry) != oe_type(src_entry))
1948                return -1;
1949
1950        /*
1951         * We do not bother to try a delta that we discarded on an
1952         * earlier try, but only when reusing delta data.  Note that
1953         * src_entry that is marked as the preferred_base should always
1954         * be considered, as even if we produce a suboptimal delta against
1955         * it, we will still save the transfer cost, as we already know
1956         * the other side has it and we won't send src_entry at all.
1957         */
1958        if (reuse_delta && IN_PACK(trg_entry) &&
1959            IN_PACK(trg_entry) == IN_PACK(src_entry) &&
1960            !src_entry->preferred_base &&
1961            trg_entry->in_pack_type != OBJ_REF_DELTA &&
1962            trg_entry->in_pack_type != OBJ_OFS_DELTA)
1963                return 0;
1964
1965        /* Let's not bust the allowed depth. */
1966        if (src->depth >= max_depth)
1967                return 0;
1968
1969        /* Now some size filtering heuristics. */
1970        trg_size = SIZE(trg_entry);
1971        if (!DELTA(trg_entry)) {
1972                max_size = trg_size/2 - the_hash_algo->rawsz;
1973                ref_depth = 1;
1974        } else {
1975                max_size = DELTA_SIZE(trg_entry);
1976                ref_depth = trg->depth;
1977        }
1978        max_size = (uint64_t)max_size * (max_depth - src->depth) /
1979                                                (max_depth - ref_depth + 1);
1980        if (max_size == 0)
1981                return 0;
1982        src_size = SIZE(src_entry);
1983        sizediff = src_size < trg_size ? trg_size - src_size : 0;
1984        if (sizediff >= max_size)
1985                return 0;
1986        if (trg_size < src_size / 32)
1987                return 0;
1988
1989        /* Load data if not already done */
1990        if (!trg->data) {
1991                read_lock();
1992                trg->data = read_object_file(&trg_entry->idx.oid, &type, &sz);
1993                read_unlock();
1994                if (!trg->data)
1995                        die(_("object %s cannot be read"),
1996                            oid_to_hex(&trg_entry->idx.oid));
1997                if (sz != trg_size)
1998                        die(_("object %s inconsistent object length (%lu vs %lu)"),
1999                            oid_to_hex(&trg_entry->idx.oid), sz,
2000                            trg_size);
2001                *mem_usage += sz;
2002        }
2003        if (!src->data) {
2004                read_lock();
2005                src->data = read_object_file(&src_entry->idx.oid, &type, &sz);
2006                read_unlock();
2007                if (!src->data) {
2008                        if (src_entry->preferred_base) {
2009                                static int warned = 0;
2010                                if (!warned++)
2011                                        warning(_("object %s cannot be read"),
2012                                                oid_to_hex(&src_entry->idx.oid));
2013                                /*
2014                                 * Those objects are not included in the
2015                                 * resulting pack.  Be resilient and ignore
2016                                 * them if they can't be read, in case the
2017                                 * pack could be created nevertheless.
2018                                 */
2019                                return 0;
2020                        }
2021                        die(_("object %s cannot be read"),
2022                            oid_to_hex(&src_entry->idx.oid));
2023                }
2024                if (sz != src_size)
2025                        die(_("object %s inconsistent object length (%lu vs %lu)"),
2026                            oid_to_hex(&src_entry->idx.oid), sz,
2027                            src_size);
2028                *mem_usage += sz;
2029        }
2030        if (!src->index) {
2031                src->index = create_delta_index(src->data, src_size);
2032                if (!src->index) {
2033                        static int warned = 0;
2034                        if (!warned++)
2035                                warning(_("suboptimal pack - out of memory"));
2036                        return 0;
2037                }
2038                *mem_usage += sizeof_delta_index(src->index);
2039        }
2040
2041        delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
2042        if (!delta_buf)
2043                return 0;
2044        if (delta_size >= (1U << OE_DELTA_SIZE_BITS)) {
2045                free(delta_buf);
2046                return 0;
2047        }
2048
2049        if (DELTA(trg_entry)) {
2050                /* Prefer only shallower same-sized deltas. */
2051                if (delta_size == DELTA_SIZE(trg_entry) &&
2052                    src->depth + 1 >= trg->depth) {
2053                        free(delta_buf);
2054                        return 0;
2055                }
2056        }
2057
2058        /*
2059         * Handle memory allocation outside of the cache
2060         * accounting lock.  Compiler will optimize the strangeness
2061         * away when NO_PTHREADS is defined.
2062         */
2063        free(trg_entry->delta_data);
2064        cache_lock();
2065        if (trg_entry->delta_data) {
2066                delta_cache_size -= DELTA_SIZE(trg_entry);
2067                trg_entry->delta_data = NULL;
2068        }
2069        if (delta_cacheable(src_size, trg_size, delta_size)) {
2070                delta_cache_size += delta_size;
2071                cache_unlock();
2072                trg_entry->delta_data = xrealloc(delta_buf, delta_size);
2073        } else {
2074                cache_unlock();
2075                free(delta_buf);
2076        }
2077
2078        SET_DELTA(trg_entry, src_entry);
2079        SET_DELTA_SIZE(trg_entry, delta_size);
2080        trg->depth = src->depth + 1;
2081
2082        return 1;
2083}
2084
2085static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
2086{
2087        struct object_entry *child = DELTA_CHILD(me);
2088        unsigned int m = n;
2089        while (child) {
2090                unsigned int c = check_delta_limit(child, n + 1);
2091                if (m < c)
2092                        m = c;
2093                child = DELTA_SIBLING(child);
2094        }
2095        return m;
2096}
2097
2098static unsigned long free_unpacked(struct unpacked *n)
2099{
2100        unsigned long freed_mem = sizeof_delta_index(n->index);
2101        free_delta_index(n->index);
2102        n->index = NULL;
2103        if (n->data) {
2104                freed_mem += SIZE(n->entry);
2105                FREE_AND_NULL(n->data);
2106        }
2107        n->entry = NULL;
2108        n->depth = 0;
2109        return freed_mem;
2110}
2111
2112static void find_deltas(struct object_entry **list, unsigned *list_size,
2113                        int window, int depth, unsigned *processed)
2114{
2115        uint32_t i, idx = 0, count = 0;
2116        struct unpacked *array;
2117        unsigned long mem_usage = 0;
2118
2119        array = xcalloc(window, sizeof(struct unpacked));
2120
2121        for (;;) {
2122                struct object_entry *entry;
2123                struct unpacked *n = array + idx;
2124                int j, max_depth, best_base = -1;
2125
2126                progress_lock();
2127                if (!*list_size) {
2128                        progress_unlock();
2129                        break;
2130                }
2131                entry = *list++;
2132                (*list_size)--;
2133                if (!entry->preferred_base) {
2134                        (*processed)++;
2135                        display_progress(progress_state, *processed);
2136                }
2137                progress_unlock();
2138
2139                mem_usage -= free_unpacked(n);
2140                n->entry = entry;
2141
2142                while (window_memory_limit &&
2143                       mem_usage > window_memory_limit &&
2144                       count > 1) {
2145                        uint32_t tail = (idx + window - count) % window;
2146                        mem_usage -= free_unpacked(array + tail);
2147                        count--;
2148                }
2149
2150                /* We do not compute delta to *create* objects we are not
2151                 * going to pack.
2152                 */
2153                if (entry->preferred_base)
2154                        goto next;
2155
2156                /*
2157                 * If the current object is at pack edge, take the depth the
2158                 * objects that depend on the current object into account
2159                 * otherwise they would become too deep.
2160                 */
2161                max_depth = depth;
2162                if (DELTA_CHILD(entry)) {
2163                        max_depth -= check_delta_limit(entry, 0);
2164                        if (max_depth <= 0)
2165                                goto next;
2166                }
2167
2168                j = window;
2169                while (--j > 0) {
2170                        int ret;
2171                        uint32_t other_idx = idx + j;
2172                        struct unpacked *m;
2173                        if (other_idx >= window)
2174                                other_idx -= window;
2175                        m = array + other_idx;
2176                        if (!m->entry)
2177                                break;
2178                        ret = try_delta(n, m, max_depth, &mem_usage);
2179                        if (ret < 0)
2180                                break;
2181                        else if (ret > 0)
2182                                best_base = other_idx;
2183                }
2184
2185                /*
2186                 * If we decided to cache the delta data, then it is best
2187                 * to compress it right away.  First because we have to do
2188                 * it anyway, and doing it here while we're threaded will
2189                 * save a lot of time in the non threaded write phase,
2190                 * as well as allow for caching more deltas within
2191                 * the same cache size limit.
2192                 * ...
2193                 * But only if not writing to stdout, since in that case
2194                 * the network is most likely throttling writes anyway,
2195                 * and therefore it is best to go to the write phase ASAP
2196                 * instead, as we can afford spending more time compressing
2197                 * between writes at that moment.
2198                 */
2199                if (entry->delta_data && !pack_to_stdout) {
2200                        unsigned long size;
2201
2202                        size = do_compress(&entry->delta_data, DELTA_SIZE(entry));
2203                        if (size < (1U << OE_Z_DELTA_BITS)) {
2204                                entry->z_delta_size = size;
2205                                cache_lock();
2206                                delta_cache_size -= DELTA_SIZE(entry);
2207                                delta_cache_size += entry->z_delta_size;
2208                                cache_unlock();
2209                        } else {
2210                                FREE_AND_NULL(entry->delta_data);
2211                                entry->z_delta_size = 0;
2212                        }
2213                }
2214
2215                /* if we made n a delta, and if n is already at max
2216                 * depth, leaving it in the window is pointless.  we
2217                 * should evict it first.
2218                 */
2219                if (DELTA(entry) && max_depth <= n->depth)
2220                        continue;
2221
2222                /*
2223                 * Move the best delta base up in the window, after the
2224                 * currently deltified object, to keep it longer.  It will
2225                 * be the first base object to be attempted next.
2226                 */
2227                if (DELTA(entry)) {
2228                        struct unpacked swap = array[best_base];
2229                        int dist = (window + idx - best_base) % window;
2230                        int dst = best_base;
2231                        while (dist--) {
2232                                int src = (dst + 1) % window;
2233                                array[dst] = array[src];
2234                                dst = src;
2235                        }
2236                        array[dst] = swap;
2237                }
2238
2239                next:
2240                idx++;
2241                if (count + 1 < window)
2242                        count++;
2243                if (idx >= window)
2244                        idx = 0;
2245        }
2246
2247        for (i = 0; i < window; ++i) {
2248                free_delta_index(array[i].index);
2249                free(array[i].data);
2250        }
2251        free(array);
2252}
2253
2254#ifndef NO_PTHREADS
2255
2256static void try_to_free_from_threads(size_t size)
2257{
2258        read_lock();
2259        release_pack_memory(size);
2260        read_unlock();
2261}
2262
2263static try_to_free_t old_try_to_free_routine;
2264
2265/*
2266 * The main object list is split into smaller lists, each is handed to
2267 * one worker.
2268 *
2269 * The main thread waits on the condition that (at least) one of the workers
2270 * has stopped working (which is indicated in the .working member of
2271 * struct thread_params).
2272 *
2273 * When a work thread has completed its work, it sets .working to 0 and
2274 * signals the main thread and waits on the condition that .data_ready
2275 * becomes 1.
2276 *
2277 * The main thread steals half of the work from the worker that has
2278 * most work left to hand it to the idle worker.
2279 */
2280
2281struct thread_params {
2282        pthread_t thread;
2283        struct object_entry **list;
2284        unsigned list_size;
2285        unsigned remaining;
2286        int window;
2287        int depth;
2288        int working;
2289        int data_ready;
2290        pthread_mutex_t mutex;
2291        pthread_cond_t cond;
2292        unsigned *processed;
2293};
2294
2295static pthread_cond_t progress_cond;
2296
2297/*
2298 * Mutex and conditional variable can't be statically-initialized on Windows.
2299 */
2300static void init_threaded_search(void)
2301{
2302        init_recursive_mutex(&read_mutex);
2303        pthread_mutex_init(&cache_mutex, NULL);
2304        pthread_mutex_init(&progress_mutex, NULL);
2305        pthread_cond_init(&progress_cond, NULL);
2306        old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
2307}
2308
2309static void cleanup_threaded_search(void)
2310{
2311        set_try_to_free_routine(old_try_to_free_routine);
2312        pthread_cond_destroy(&progress_cond);
2313        pthread_mutex_destroy(&read_mutex);
2314        pthread_mutex_destroy(&cache_mutex);
2315        pthread_mutex_destroy(&progress_mutex);
2316}
2317
2318static void *threaded_find_deltas(void *arg)
2319{
2320        struct thread_params *me = arg;
2321
2322        progress_lock();
2323        while (me->remaining) {
2324                progress_unlock();
2325
2326                find_deltas(me->list, &me->remaining,
2327                            me->window, me->depth, me->processed);
2328
2329                progress_lock();
2330                me->working = 0;
2331                pthread_cond_signal(&progress_cond);
2332                progress_unlock();
2333
2334                /*
2335                 * We must not set ->data_ready before we wait on the
2336                 * condition because the main thread may have set it to 1
2337                 * before we get here. In order to be sure that new
2338                 * work is available if we see 1 in ->data_ready, it
2339                 * was initialized to 0 before this thread was spawned
2340                 * and we reset it to 0 right away.
2341                 */
2342                pthread_mutex_lock(&me->mutex);
2343                while (!me->data_ready)
2344                        pthread_cond_wait(&me->cond, &me->mutex);
2345                me->data_ready = 0;
2346                pthread_mutex_unlock(&me->mutex);
2347
2348                progress_lock();
2349        }
2350        progress_unlock();
2351        /* leave ->working 1 so that this doesn't get more work assigned */
2352        return NULL;
2353}
2354
2355static void ll_find_deltas(struct object_entry **list, unsigned list_size,
2356                           int window, int depth, unsigned *processed)
2357{
2358        struct thread_params *p;
2359        int i, ret, active_threads = 0;
2360
2361        init_threaded_search();
2362
2363        if (delta_search_threads <= 1) {
2364                find_deltas(list, &list_size, window, depth, processed);
2365                cleanup_threaded_search();
2366                return;
2367        }
2368        if (progress > pack_to_stdout)
2369                fprintf_ln(stderr, _("Delta compression using up to %d threads"),
2370                           delta_search_threads);
2371        p = xcalloc(delta_search_threads, sizeof(*p));
2372
2373        /* Partition the work amongst work threads. */
2374        for (i = 0; i < delta_search_threads; i++) {
2375                unsigned sub_size = list_size / (delta_search_threads - i);
2376
2377                /* don't use too small segments or no deltas will be found */
2378                if (sub_size < 2*window && i+1 < delta_search_threads)
2379                        sub_size = 0;
2380
2381                p[i].window = window;
2382                p[i].depth = depth;
2383                p[i].processed = processed;
2384                p[i].working = 1;
2385                p[i].data_ready = 0;
2386
2387                /* try to split chunks on "path" boundaries */
2388                while (sub_size && sub_size < list_size &&
2389                       list[sub_size]->hash &&
2390                       list[sub_size]->hash == list[sub_size-1]->hash)
2391                        sub_size++;
2392
2393                p[i].list = list;
2394                p[i].list_size = sub_size;
2395                p[i].remaining = sub_size;
2396
2397                list += sub_size;
2398                list_size -= sub_size;
2399        }
2400
2401        /* Start work threads. */
2402        for (i = 0; i < delta_search_threads; i++) {
2403                if (!p[i].list_size)
2404                        continue;
2405                pthread_mutex_init(&p[i].mutex, NULL);
2406                pthread_cond_init(&p[i].cond, NULL);
2407                ret = pthread_create(&p[i].thread, NULL,
2408                                     threaded_find_deltas, &p[i]);
2409                if (ret)
2410                        die(_("unable to create thread: %s"), strerror(ret));
2411                active_threads++;
2412        }
2413
2414        /*
2415         * Now let's wait for work completion.  Each time a thread is done
2416         * with its work, we steal half of the remaining work from the
2417         * thread with the largest number of unprocessed objects and give
2418         * it to that newly idle thread.  This ensure good load balancing
2419         * until the remaining object list segments are simply too short
2420         * to be worth splitting anymore.
2421         */
2422        while (active_threads) {
2423                struct thread_params *target = NULL;
2424                struct thread_params *victim = NULL;
2425                unsigned sub_size = 0;
2426
2427                progress_lock();
2428                for (;;) {
2429                        for (i = 0; !target && i < delta_search_threads; i++)
2430                                if (!p[i].working)
2431                                        target = &p[i];
2432                        if (target)
2433                                break;
2434                        pthread_cond_wait(&progress_cond, &progress_mutex);
2435                }
2436
2437                for (i = 0; i < delta_search_threads; i++)
2438                        if (p[i].remaining > 2*window &&
2439                            (!victim || victim->remaining < p[i].remaining))
2440                                victim = &p[i];
2441                if (victim) {
2442                        sub_size = victim->remaining / 2;
2443                        list = victim->list + victim->list_size - sub_size;
2444                        while (sub_size && list[0]->hash &&
2445                               list[0]->hash == list[-1]->hash) {
2446                                list++;
2447                                sub_size--;
2448                        }
2449                        if (!sub_size) {
2450                                /*
2451                                 * It is possible for some "paths" to have
2452                                 * so many objects that no hash boundary
2453                                 * might be found.  Let's just steal the
2454                                 * exact half in that case.
2455                                 */
2456                                sub_size = victim->remaining / 2;
2457                                list -= sub_size;
2458                        }
2459                        target->list = list;
2460                        victim->list_size -= sub_size;
2461                        victim->remaining -= sub_size;
2462                }
2463                target->list_size = sub_size;
2464                target->remaining = sub_size;
2465                target->working = 1;
2466                progress_unlock();
2467
2468                pthread_mutex_lock(&target->mutex);
2469                target->data_ready = 1;
2470                pthread_cond_signal(&target->cond);
2471                pthread_mutex_unlock(&target->mutex);
2472
2473                if (!sub_size) {
2474                        pthread_join(target->thread, NULL);
2475                        pthread_cond_destroy(&target->cond);
2476                        pthread_mutex_destroy(&target->mutex);
2477                        active_threads--;
2478                }
2479        }
2480        cleanup_threaded_search();
2481        free(p);
2482}
2483
2484#else
2485#define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
2486#endif
2487
2488static void add_tag_chain(const struct object_id *oid)
2489{
2490        struct tag *tag;
2491
2492        /*
2493         * We catch duplicates already in add_object_entry(), but we'd
2494         * prefer to do this extra check to avoid having to parse the
2495         * tag at all if we already know that it's being packed (e.g., if
2496         * it was included via bitmaps, we would not have parsed it
2497         * previously).
2498         */
2499        if (packlist_find(&to_pack, oid->hash, NULL))
2500                return;
2501
2502        tag = lookup_tag(the_repository, oid);
2503        while (1) {
2504                if (!tag || parse_tag(tag) || !tag->tagged)
2505                        die(_("unable to pack objects reachable from tag %s"),
2506                            oid_to_hex(oid));
2507
2508                add_object_entry(&tag->object.oid, OBJ_TAG, NULL, 0);
2509
2510                if (tag->tagged->type != OBJ_TAG)
2511                        return;
2512
2513                tag = (struct tag *)tag->tagged;
2514        }
2515}
2516
2517static int add_ref_tag(const char *path, const struct object_id *oid, int flag, void *cb_data)
2518{
2519        struct object_id peeled;
2520
2521        if (starts_with(path, "refs/tags/") && /* is a tag? */
2522            !peel_ref(path, &peeled)    && /* peelable? */
2523            packlist_find(&to_pack, peeled.hash, NULL))      /* object packed? */
2524                add_tag_chain(oid);
2525        return 0;
2526}
2527
2528static void prepare_pack(int window, int depth)
2529{
2530        struct object_entry **delta_list;
2531        uint32_t i, nr_deltas;
2532        unsigned n;
2533
2534        get_object_details();
2535
2536        /*
2537         * If we're locally repacking then we need to be doubly careful
2538         * from now on in order to make sure no stealth corruption gets
2539         * propagated to the new pack.  Clients receiving streamed packs
2540         * should validate everything they get anyway so no need to incur
2541         * the additional cost here in that case.
2542         */
2543        if (!pack_to_stdout)
2544                do_check_packed_object_crc = 1;
2545
2546        if (!to_pack.nr_objects || !window || !depth)
2547                return;
2548
2549        ALLOC_ARRAY(delta_list, to_pack.nr_objects);
2550        nr_deltas = n = 0;
2551
2552        for (i = 0; i < to_pack.nr_objects; i++) {
2553                struct object_entry *entry = to_pack.objects + i;
2554
2555                if (DELTA(entry))
2556                        /* This happens if we decided to reuse existing
2557                         * delta from a pack.  "reuse_delta &&" is implied.
2558                         */
2559                        continue;
2560
2561                if (!entry->type_valid ||
2562                    oe_size_less_than(&to_pack, entry, 50))
2563                        continue;
2564
2565                if (entry->no_try_delta)
2566                        continue;
2567
2568                if (!entry->preferred_base) {
2569                        nr_deltas++;
2570                        if (oe_type(entry) < 0)
2571                                die(_("unable to get type of object %s"),
2572                                    oid_to_hex(&entry->idx.oid));
2573                } else {
2574                        if (oe_type(entry) < 0) {
2575                                /*
2576                                 * This object is not found, but we
2577                                 * don't have to include it anyway.
2578                                 */
2579                                continue;
2580                        }
2581                }
2582
2583                delta_list[n++] = entry;
2584        }
2585
2586        if (nr_deltas && n > 1) {
2587                unsigned nr_done = 0;
2588                if (progress)
2589                        progress_state = start_progress(_("Compressing objects"),
2590                                                        nr_deltas);
2591                QSORT(delta_list, n, type_size_sort);
2592                ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2593                stop_progress(&progress_state);
2594                if (nr_done != nr_deltas)
2595                        die(_("inconsistency with delta count"));
2596        }
2597        free(delta_list);
2598}
2599
2600static int git_pack_config(const char *k, const char *v, void *cb)
2601{
2602        if (!strcmp(k, "pack.window")) {
2603                window = git_config_int(k, v);
2604                return 0;
2605        }
2606        if (!strcmp(k, "pack.windowmemory")) {
2607                window_memory_limit = git_config_ulong(k, v);
2608                return 0;
2609        }
2610        if (!strcmp(k, "pack.depth")) {
2611                depth = git_config_int(k, v);
2612                return 0;
2613        }
2614        if (!strcmp(k, "pack.deltacachesize")) {
2615                max_delta_cache_size = git_config_int(k, v);
2616                return 0;
2617        }
2618        if (!strcmp(k, "pack.deltacachelimit")) {
2619                cache_max_small_delta_size = git_config_int(k, v);
2620                return 0;
2621        }
2622        if (!strcmp(k, "pack.writebitmaphashcache")) {
2623                if (git_config_bool(k, v))
2624                        write_bitmap_options |= BITMAP_OPT_HASH_CACHE;
2625                else
2626                        write_bitmap_options &= ~BITMAP_OPT_HASH_CACHE;
2627        }
2628        if (!strcmp(k, "pack.usebitmaps")) {
2629                use_bitmap_index_default = git_config_bool(k, v);
2630                return 0;
2631        }
2632        if (!strcmp(k, "pack.threads")) {
2633                delta_search_threads = git_config_int(k, v);
2634                if (delta_search_threads < 0)
2635                        die(_("invalid number of threads specified (%d)"),
2636                            delta_search_threads);
2637#ifdef NO_PTHREADS
2638                if (delta_search_threads != 1) {
2639                        warning(_("no threads support, ignoring %s"), k);
2640                        delta_search_threads = 0;
2641                }
2642#endif
2643                return 0;
2644        }
2645        if (!strcmp(k, "pack.indexversion")) {
2646                pack_idx_opts.version = git_config_int(k, v);
2647                if (pack_idx_opts.version > 2)
2648                        die(_("bad pack.indexversion=%"PRIu32),
2649                            pack_idx_opts.version);
2650                return 0;
2651        }
2652        return git_default_config(k, v, cb);
2653}
2654
2655static void read_object_list_from_stdin(void)
2656{
2657        char line[GIT_MAX_HEXSZ + 1 + PATH_MAX + 2];
2658        struct object_id oid;
2659        const char *p;
2660
2661        for (;;) {
2662                if (!fgets(line, sizeof(line), stdin)) {
2663                        if (feof(stdin))
2664                                break;
2665                        if (!ferror(stdin))
2666                                die("BUG: fgets returned NULL, not EOF, not error!");
2667                        if (errno != EINTR)
2668                                die_errno("fgets");
2669                        clearerr(stdin);
2670                        continue;
2671                }
2672                if (line[0] == '-') {
2673                        if (get_oid_hex(line+1, &oid))
2674                                die(_("expected edge object ID, got garbage:\n %s"),
2675                                    line);
2676                        add_preferred_base(&oid);
2677                        continue;
2678                }
2679                if (parse_oid_hex(line, &oid, &p))
2680                        die(_("expected object ID, got garbage:\n %s"), line);
2681
2682                add_preferred_base_object(p + 1);
2683                add_object_entry(&oid, OBJ_NONE, p + 1, 0);
2684        }
2685}
2686
2687/* Remember to update object flag allocation in object.h */
2688#define OBJECT_ADDED (1u<<20)
2689
2690static void show_commit(struct commit *commit, void *data)
2691{
2692        add_object_entry(&commit->object.oid, OBJ_COMMIT, NULL, 0);
2693        commit->object.flags |= OBJECT_ADDED;
2694
2695        if (write_bitmap_index)
2696                index_commit_for_bitmap(commit);
2697}
2698
2699static void show_object(struct object *obj, const char *name, void *data)
2700{
2701        add_preferred_base_object(name);
2702        add_object_entry(&obj->oid, obj->type, name, 0);
2703        obj->flags |= OBJECT_ADDED;
2704}
2705
2706static void show_object__ma_allow_any(struct object *obj, const char *name, void *data)
2707{
2708        assert(arg_missing_action == MA_ALLOW_ANY);
2709
2710        /*
2711         * Quietly ignore ALL missing objects.  This avoids problems with
2712         * staging them now and getting an odd error later.
2713         */
2714        if (!has_object_file(&obj->oid))
2715                return;
2716
2717        show_object(obj, name, data);
2718}
2719
2720static void show_object__ma_allow_promisor(struct object *obj, const char *name, void *data)
2721{
2722        assert(arg_missing_action == MA_ALLOW_PROMISOR);
2723
2724        /*
2725         * Quietly ignore EXPECTED missing objects.  This avoids problems with
2726         * staging them now and getting an odd error later.
2727         */
2728        if (!has_object_file(&obj->oid) && is_promisor_object(&obj->oid))
2729                return;
2730
2731        show_object(obj, name, data);
2732}
2733
2734static int option_parse_missing_action(const struct option *opt,
2735                                       const char *arg, int unset)
2736{
2737        assert(arg);
2738        assert(!unset);
2739
2740        if (!strcmp(arg, "error")) {
2741                arg_missing_action = MA_ERROR;
2742                fn_show_object = show_object;
2743                return 0;
2744        }
2745
2746        if (!strcmp(arg, "allow-any")) {
2747                arg_missing_action = MA_ALLOW_ANY;
2748                fetch_if_missing = 0;
2749                fn_show_object = show_object__ma_allow_any;
2750                return 0;
2751        }
2752
2753        if (!strcmp(arg, "allow-promisor")) {
2754                arg_missing_action = MA_ALLOW_PROMISOR;
2755                fetch_if_missing = 0;
2756                fn_show_object = show_object__ma_allow_promisor;
2757                return 0;
2758        }
2759
2760        die(_("invalid value for --missing"));
2761        return 0;
2762}
2763
2764static void show_edge(struct commit *commit)
2765{
2766        add_preferred_base(&commit->object.oid);
2767}
2768
2769struct in_pack_object {
2770        off_t offset;
2771        struct object *object;
2772};
2773
2774struct in_pack {
2775        unsigned int alloc;
2776        unsigned int nr;
2777        struct in_pack_object *array;
2778};
2779
2780static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2781{
2782        in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->oid.hash, p);
2783        in_pack->array[in_pack->nr].object = object;
2784        in_pack->nr++;
2785}
2786
2787/*
2788 * Compare the objects in the offset order, in order to emulate the
2789 * "git rev-list --objects" output that produced the pack originally.
2790 */
2791static int ofscmp(const void *a_, const void *b_)
2792{
2793        struct in_pack_object *a = (struct in_pack_object *)a_;
2794        struct in_pack_object *b = (struct in_pack_object *)b_;
2795
2796        if (a->offset < b->offset)
2797                return -1;
2798        else if (a->offset > b->offset)
2799                return 1;
2800        else
2801                return oidcmp(&a->object->oid, &b->object->oid);
2802}
2803
2804static void add_objects_in_unpacked_packs(struct rev_info *revs)
2805{
2806        struct packed_git *p;
2807        struct in_pack in_pack;
2808        uint32_t i;
2809
2810        memset(&in_pack, 0, sizeof(in_pack));
2811
2812        for (p = get_packed_git(the_repository); p; p = p->next) {
2813                struct object_id oid;
2814                struct object *o;
2815
2816                if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
2817                        continue;
2818                if (open_pack_index(p))
2819                        die(_("cannot open pack index"));
2820
2821                ALLOC_GROW(in_pack.array,
2822                           in_pack.nr + p->num_objects,
2823                           in_pack.alloc);
2824
2825                for (i = 0; i < p->num_objects; i++) {
2826                        nth_packed_object_oid(&oid, p, i);
2827                        o = lookup_unknown_object(oid.hash);
2828                        if (!(o->flags & OBJECT_ADDED))
2829                                mark_in_pack_object(o, p, &in_pack);
2830                        o->flags |= OBJECT_ADDED;
2831                }
2832        }
2833
2834        if (in_pack.nr) {
2835                QSORT(in_pack.array, in_pack.nr, ofscmp);
2836                for (i = 0; i < in_pack.nr; i++) {
2837                        struct object *o = in_pack.array[i].object;
2838                        add_object_entry(&o->oid, o->type, "", 0);
2839                }
2840        }
2841        free(in_pack.array);
2842}
2843
2844static int add_loose_object(const struct object_id *oid, const char *path,
2845                            void *data)
2846{
2847        enum object_type type = oid_object_info(the_repository, oid, NULL);
2848
2849        if (type < 0) {
2850                warning(_("loose object at %s could not be examined"), path);
2851                return 0;
2852        }
2853
2854        add_object_entry(oid, type, "", 0);
2855        return 0;
2856}
2857
2858/*
2859 * We actually don't even have to worry about reachability here.
2860 * add_object_entry will weed out duplicates, so we just add every
2861 * loose object we find.
2862 */
2863static void add_unreachable_loose_objects(void)
2864{
2865        for_each_loose_file_in_objdir(get_object_directory(),
2866                                      add_loose_object,
2867                                      NULL, NULL, NULL);
2868}
2869
2870static int has_sha1_pack_kept_or_nonlocal(const struct object_id *oid)
2871{
2872        static struct packed_git *last_found = (void *)1;
2873        struct packed_git *p;
2874
2875        p = (last_found != (void *)1) ? last_found :
2876                                        get_packed_git(the_repository);
2877
2878        while (p) {
2879                if ((!p->pack_local || p->pack_keep ||
2880                                p->pack_keep_in_core) &&
2881                        find_pack_entry_one(oid->hash, p)) {
2882                        last_found = p;
2883                        return 1;
2884                }
2885                if (p == last_found)
2886                        p = get_packed_git(the_repository);
2887                else
2888                        p = p->next;
2889                if (p == last_found)
2890                        p = p->next;
2891        }
2892        return 0;
2893}
2894
2895/*
2896 * Store a list of sha1s that are should not be discarded
2897 * because they are either written too recently, or are
2898 * reachable from another object that was.
2899 *
2900 * This is filled by get_object_list.
2901 */
2902static struct oid_array recent_objects;
2903
2904static int loosened_object_can_be_discarded(const struct object_id *oid,
2905                                            timestamp_t mtime)
2906{
2907        if (!unpack_unreachable_expiration)
2908                return 0;
2909        if (mtime > unpack_unreachable_expiration)
2910                return 0;
2911        if (oid_array_lookup(&recent_objects, oid) >= 0)
2912                return 0;
2913        return 1;
2914}
2915
2916static void loosen_unused_packed_objects(struct rev_info *revs)
2917{
2918        struct packed_git *p;
2919        uint32_t i;
2920        struct object_id oid;
2921
2922        for (p = get_packed_git(the_repository); p; p = p->next) {
2923                if (!p->pack_local || p->pack_keep || p->pack_keep_in_core)
2924                        continue;
2925
2926                if (open_pack_index(p))
2927                        die(_("cannot open pack index"));
2928
2929                for (i = 0; i < p->num_objects; i++) {
2930                        nth_packed_object_oid(&oid, p, i);
2931                        if (!packlist_find(&to_pack, oid.hash, NULL) &&
2932                            !has_sha1_pack_kept_or_nonlocal(&oid) &&
2933                            !loosened_object_can_be_discarded(&oid, p->mtime))
2934                                if (force_object_loose(&oid, p->mtime))
2935                                        die(_("unable to force loose object"));
2936                }
2937        }
2938}
2939
2940/*
2941 * This tracks any options which pack-reuse code expects to be on, or which a
2942 * reader of the pack might not understand, and which would therefore prevent
2943 * blind reuse of what we have on disk.
2944 */
2945static int pack_options_allow_reuse(void)
2946{
2947        return pack_to_stdout &&
2948               allow_ofs_delta &&
2949               !ignore_packed_keep_on_disk &&
2950               !ignore_packed_keep_in_core &&
2951               (!local || !have_non_local_packs) &&
2952               !incremental;
2953}
2954
2955static int get_object_list_from_bitmap(struct rev_info *revs)
2956{
2957        struct bitmap_index *bitmap_git;
2958        if (!(bitmap_git = prepare_bitmap_walk(revs)))
2959                return -1;
2960
2961        if (pack_options_allow_reuse() &&
2962            !reuse_partial_packfile_from_bitmap(
2963                        bitmap_git,
2964                        &reuse_packfile,
2965                        &reuse_packfile_objects,
2966                        &reuse_packfile_offset)) {
2967                assert(reuse_packfile_objects);
2968                nr_result += reuse_packfile_objects;
2969                display_progress(progress_state, nr_result);
2970        }
2971
2972        traverse_bitmap_commit_list(bitmap_git, &add_object_entry_from_bitmap);
2973        free_bitmap_index(bitmap_git);
2974        return 0;
2975}
2976
2977static void record_recent_object(struct object *obj,
2978                                 const char *name,
2979                                 void *data)
2980{
2981        oid_array_append(&recent_objects, &obj->oid);
2982}
2983
2984static void record_recent_commit(struct commit *commit, void *data)
2985{
2986        oid_array_append(&recent_objects, &commit->object.oid);
2987}
2988
2989static void get_object_list(int ac, const char **av)
2990{
2991        struct rev_info revs;
2992        char line[1000];
2993        int flags = 0;
2994
2995        init_revisions(&revs, NULL);
2996        save_commit_buffer = 0;
2997        setup_revisions(ac, av, &revs, NULL);
2998
2999        /* make sure shallows are read */
3000        is_repository_shallow(the_repository);
3001
3002        while (fgets(line, sizeof(line), stdin) != NULL) {
3003                int len = strlen(line);
3004                if (len && line[len - 1] == '\n')
3005                        line[--len] = 0;
3006                if (!len)
3007                        break;
3008                if (*line == '-') {
3009                        if (!strcmp(line, "--not")) {
3010                                flags ^= UNINTERESTING;
3011                                write_bitmap_index = 0;
3012                                continue;
3013                        }
3014                        if (starts_with(line, "--shallow ")) {
3015                                struct object_id oid;
3016                                if (get_oid_hex(line + 10, &oid))
3017                                        die("not an SHA-1 '%s'", line + 10);
3018                                register_shallow(the_repository, &oid);
3019                                use_bitmap_index = 0;
3020                                continue;
3021                        }
3022                        die(_("not a rev '%s'"), line);
3023                }
3024                if (handle_revision_arg(line, &revs, flags, REVARG_CANNOT_BE_FILENAME))
3025                        die(_("bad revision '%s'"), line);
3026        }
3027
3028        if (use_bitmap_index && !get_object_list_from_bitmap(&revs))
3029                return;
3030
3031        if (prepare_revision_walk(&revs))
3032                die(_("revision walk setup failed"));
3033        mark_edges_uninteresting(&revs, show_edge);
3034
3035        if (!fn_show_object)
3036                fn_show_object = show_object;
3037        traverse_commit_list_filtered(&filter_options, &revs,
3038                                      show_commit, fn_show_object, NULL,
3039                                      NULL);
3040
3041        if (unpack_unreachable_expiration) {
3042                revs.ignore_missing_links = 1;
3043                if (add_unseen_recent_objects_to_traversal(&revs,
3044                                unpack_unreachable_expiration))
3045                        die(_("unable to add recent objects"));
3046                if (prepare_revision_walk(&revs))
3047                        die(_("revision walk setup failed"));
3048                traverse_commit_list(&revs, record_recent_commit,
3049                                     record_recent_object, NULL);
3050        }
3051
3052        if (keep_unreachable)
3053                add_objects_in_unpacked_packs(&revs);
3054        if (pack_loose_unreachable)
3055                add_unreachable_loose_objects();
3056        if (unpack_unreachable)
3057                loosen_unused_packed_objects(&revs);
3058
3059        oid_array_clear(&recent_objects);
3060}
3061
3062static void add_extra_kept_packs(const struct string_list *names)
3063{
3064        struct packed_git *p;
3065
3066        if (!names->nr)
3067                return;
3068
3069        for (p = get_packed_git(the_repository); p; p = p->next) {
3070                const char *name = basename(p->pack_name);
3071                int i;
3072
3073                if (!p->pack_local)
3074                        continue;
3075
3076                for (i = 0; i < names->nr; i++)
3077                        if (!fspathcmp(name, names->items[i].string))
3078                                break;
3079
3080                if (i < names->nr) {
3081                        p->pack_keep_in_core = 1;
3082                        ignore_packed_keep_in_core = 1;
3083                        continue;
3084                }
3085        }
3086}
3087
3088static int option_parse_index_version(const struct option *opt,
3089                                      const char *arg, int unset)
3090{
3091        char *c;
3092        const char *val = arg;
3093        pack_idx_opts.version = strtoul(val, &c, 10);
3094        if (pack_idx_opts.version > 2)
3095                die(_("unsupported index version %s"), val);
3096        if (*c == ',' && c[1])
3097                pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
3098        if (*c || pack_idx_opts.off32_limit & 0x80000000)
3099                die(_("bad index version '%s'"), val);
3100        return 0;
3101}
3102
3103static int option_parse_unpack_unreachable(const struct option *opt,
3104                                           const char *arg, int unset)
3105{
3106        if (unset) {
3107                unpack_unreachable = 0;
3108                unpack_unreachable_expiration = 0;
3109        }
3110        else {
3111                unpack_unreachable = 1;
3112                if (arg)
3113                        unpack_unreachable_expiration = approxidate(arg);
3114        }
3115        return 0;
3116}
3117
3118int cmd_pack_objects(int argc, const char **argv, const char *prefix)
3119{
3120        int use_internal_rev_list = 0;
3121        int thin = 0;
3122        int shallow = 0;
3123        int all_progress_implied = 0;
3124        struct argv_array rp = ARGV_ARRAY_INIT;
3125        int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
3126        int rev_list_index = 0;
3127        struct string_list keep_pack_list = STRING_LIST_INIT_NODUP;
3128        struct option pack_objects_options[] = {
3129                OPT_SET_INT('q', "quiet", &progress,
3130                            N_("do not show progress meter"), 0),
3131                OPT_SET_INT(0, "progress", &progress,
3132                            N_("show progress meter"), 1),
3133                OPT_SET_INT(0, "all-progress", &progress,
3134                            N_("show progress meter during object writing phase"), 2),
3135                OPT_BOOL(0, "all-progress-implied",
3136                         &all_progress_implied,
3137                         N_("similar to --all-progress when progress meter is shown")),
3138                { OPTION_CALLBACK, 0, "index-version", NULL, N_("<version>[,<offset>]"),
3139                  N_("write the pack index file in the specified idx format version"),
3140                  0, option_parse_index_version },
3141                OPT_MAGNITUDE(0, "max-pack-size", &pack_size_limit,
3142                              N_("maximum size of each output pack file")),
3143                OPT_BOOL(0, "local", &local,
3144                         N_("ignore borrowed objects from alternate object store")),
3145                OPT_BOOL(0, "incremental", &incremental,
3146                         N_("ignore packed objects")),
3147                OPT_INTEGER(0, "window", &window,
3148                            N_("limit pack window by objects")),
3149                OPT_MAGNITUDE(0, "window-memory", &window_memory_limit,
3150                              N_("limit pack window by memory in addition to object limit")),
3151                OPT_INTEGER(0, "depth", &depth,
3152                            N_("maximum length of delta chain allowed in the resulting pack")),
3153                OPT_BOOL(0, "reuse-delta", &reuse_delta,
3154                         N_("reuse existing deltas")),
3155                OPT_BOOL(0, "reuse-object", &reuse_object,
3156                         N_("reuse existing objects")),
3157                OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
3158                         N_("use OFS_DELTA objects")),
3159                OPT_INTEGER(0, "threads", &delta_search_threads,
3160                            N_("use threads when searching for best delta matches")),
3161                OPT_BOOL(0, "non-empty", &non_empty,
3162                         N_("do not create an empty pack output")),
3163                OPT_BOOL(0, "revs", &use_internal_rev_list,
3164                         N_("read revision arguments from standard input")),
3165                OPT_SET_INT_F(0, "unpacked", &rev_list_unpacked,
3166                              N_("limit the objects to those that are not yet packed"),
3167                              1, PARSE_OPT_NONEG),
3168                OPT_SET_INT_F(0, "all", &rev_list_all,
3169                              N_("include objects reachable from any reference"),
3170                              1, PARSE_OPT_NONEG),
3171                OPT_SET_INT_F(0, "reflog", &rev_list_reflog,
3172                              N_("include objects referred by reflog entries"),
3173                              1, PARSE_OPT_NONEG),
3174                OPT_SET_INT_F(0, "indexed-objects", &rev_list_index,
3175                              N_("include objects referred to by the index"),
3176                              1, PARSE_OPT_NONEG),
3177                OPT_BOOL(0, "stdout", &pack_to_stdout,
3178                         N_("output pack to stdout")),
3179                OPT_BOOL(0, "include-tag", &include_tag,
3180                         N_("include tag objects that refer to objects to be packed")),
3181                OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
3182                         N_("keep unreachable objects")),
3183                OPT_BOOL(0, "pack-loose-unreachable", &pack_loose_unreachable,
3184                         N_("pack loose unreachable objects")),
3185                { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, N_("time"),
3186                  N_("unpack unreachable objects newer than <time>"),
3187                  PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
3188                OPT_BOOL(0, "thin", &thin,
3189                         N_("create thin packs")),
3190                OPT_BOOL(0, "shallow", &shallow,
3191                         N_("create packs suitable for shallow fetches")),
3192                OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep_on_disk,
3193                         N_("ignore packs that have companion .keep file")),
3194                OPT_STRING_LIST(0, "keep-pack", &keep_pack_list, N_("name"),
3195                                N_("ignore this pack")),
3196                OPT_INTEGER(0, "compression", &pack_compression_level,
3197                            N_("pack compression level")),
3198                OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
3199                            N_("do not hide commits by grafts"), 0),
3200                OPT_BOOL(0, "use-bitmap-index", &use_bitmap_index,
3201                         N_("use a bitmap index if available to speed up counting objects")),
3202                OPT_BOOL(0, "write-bitmap-index", &write_bitmap_index,
3203                         N_("write a bitmap index together with the pack index")),
3204                OPT_PARSE_LIST_OBJECTS_FILTER(&filter_options),
3205                { OPTION_CALLBACK, 0, "missing", NULL, N_("action"),
3206                  N_("handling for missing objects"), PARSE_OPT_NONEG,
3207                  option_parse_missing_action },
3208                OPT_BOOL(0, "exclude-promisor-objects", &exclude_promisor_objects,
3209                         N_("do not pack objects in promisor packfiles")),
3210                OPT_END(),
3211        };
3212
3213        if (DFS_NUM_STATES > (1 << OE_DFS_STATE_BITS))
3214                BUG("too many dfs states, increase OE_DFS_STATE_BITS");
3215
3216        read_replace_refs = 0;
3217
3218        reset_pack_idx_option(&pack_idx_opts);
3219        git_config(git_pack_config, NULL);
3220
3221        progress = isatty(2);
3222        argc = parse_options(argc, argv, prefix, pack_objects_options,
3223                             pack_usage, 0);
3224
3225        if (argc) {
3226                base_name = argv[0];
3227                argc--;
3228        }
3229        if (pack_to_stdout != !base_name || argc)
3230                usage_with_options(pack_usage, pack_objects_options);
3231
3232        if (depth >= (1 << OE_DEPTH_BITS)) {
3233                warning(_("delta chain depth %d is too deep, forcing %d"),
3234                        depth, (1 << OE_DEPTH_BITS) - 1);
3235                depth = (1 << OE_DEPTH_BITS) - 1;
3236        }
3237        if (cache_max_small_delta_size >= (1U << OE_Z_DELTA_BITS)) {
3238                warning(_("pack.deltaCacheLimit is too high, forcing %d"),
3239                        (1U << OE_Z_DELTA_BITS) - 1);
3240                cache_max_small_delta_size = (1U << OE_Z_DELTA_BITS) - 1;
3241        }
3242
3243        argv_array_push(&rp, "pack-objects");
3244        if (thin) {
3245                use_internal_rev_list = 1;
3246                argv_array_push(&rp, shallow
3247                                ? "--objects-edge-aggressive"
3248                                : "--objects-edge");
3249        } else
3250                argv_array_push(&rp, "--objects");
3251
3252        if (rev_list_all) {
3253                use_internal_rev_list = 1;
3254                argv_array_push(&rp, "--all");
3255        }
3256        if (rev_list_reflog) {
3257                use_internal_rev_list = 1;
3258                argv_array_push(&rp, "--reflog");
3259        }
3260        if (rev_list_index) {
3261                use_internal_rev_list = 1;
3262                argv_array_push(&rp, "--indexed-objects");
3263        }
3264        if (rev_list_unpacked) {
3265                use_internal_rev_list = 1;
3266                argv_array_push(&rp, "--unpacked");
3267        }
3268
3269        if (exclude_promisor_objects) {
3270                use_internal_rev_list = 1;
3271                fetch_if_missing = 0;
3272                argv_array_push(&rp, "--exclude-promisor-objects");
3273        }
3274        if (unpack_unreachable || keep_unreachable || pack_loose_unreachable)
3275                use_internal_rev_list = 1;
3276
3277        if (!reuse_object)
3278                reuse_delta = 0;
3279        if (pack_compression_level == -1)
3280                pack_compression_level = Z_DEFAULT_COMPRESSION;
3281        else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
3282                die(_("bad pack compression level %d"), pack_compression_level);
3283
3284        if (!delta_search_threads)      /* --threads=0 means autodetect */
3285                delta_search_threads = online_cpus();
3286
3287#ifdef NO_PTHREADS
3288        if (delta_search_threads != 1)
3289                warning(_("no threads support, ignoring --threads"));
3290#endif
3291        if (!pack_to_stdout && !pack_size_limit)
3292                pack_size_limit = pack_size_limit_cfg;
3293        if (pack_to_stdout && pack_size_limit)
3294                die(_("--max-pack-size cannot be used to build a pack for transfer"));
3295        if (pack_size_limit && pack_size_limit < 1024*1024) {
3296                warning(_("minimum pack size limit is 1 MiB"));
3297                pack_size_limit = 1024*1024;
3298        }
3299
3300        if (!pack_to_stdout && thin)
3301                die(_("--thin cannot be used to build an indexable pack"));
3302
3303        if (keep_unreachable && unpack_unreachable)
3304                die(_("--keep-unreachable and --unpack-unreachable are incompatible"));
3305        if (!rev_list_all || !rev_list_reflog || !rev_list_index)
3306                unpack_unreachable_expiration = 0;
3307
3308        if (filter_options.choice) {
3309                if (!pack_to_stdout)
3310                        die(_("cannot use --filter without --stdout"));
3311                use_bitmap_index = 0;
3312        }
3313
3314        /*
3315         * "soft" reasons not to use bitmaps - for on-disk repack by default we want
3316         *
3317         * - to produce good pack (with bitmap index not-yet-packed objects are
3318         *   packed in suboptimal order).
3319         *
3320         * - to use more robust pack-generation codepath (avoiding possible
3321         *   bugs in bitmap code and possible bitmap index corruption).
3322         */
3323        if (!pack_to_stdout)
3324                use_bitmap_index_default = 0;
3325
3326        if (use_bitmap_index < 0)
3327                use_bitmap_index = use_bitmap_index_default;
3328
3329        /* "hard" reasons not to use bitmaps; these just won't work at all */
3330        if (!use_internal_rev_list || (!pack_to_stdout && write_bitmap_index) || is_repository_shallow(the_repository))
3331                use_bitmap_index = 0;
3332
3333        if (pack_to_stdout || !rev_list_all)
3334                write_bitmap_index = 0;
3335
3336        if (progress && all_progress_implied)
3337                progress = 2;
3338
3339        add_extra_kept_packs(&keep_pack_list);
3340        if (ignore_packed_keep_on_disk) {
3341                struct packed_git *p;
3342                for (p = get_packed_git(the_repository); p; p = p->next)
3343                        if (p->pack_local && p->pack_keep)
3344                                break;
3345                if (!p) /* no keep-able packs found */
3346                        ignore_packed_keep_on_disk = 0;
3347        }
3348        if (local) {
3349                /*
3350                 * unlike ignore_packed_keep_on_disk above, we do not
3351                 * want to unset "local" based on looking at packs, as
3352                 * it also covers non-local objects
3353                 */
3354                struct packed_git *p;
3355                for (p = get_packed_git(the_repository); p; p = p->next) {
3356                        if (!p->pack_local) {
3357                                have_non_local_packs = 1;
3358                                break;
3359                        }
3360                }
3361        }
3362
3363        prepare_packing_data(&to_pack);
3364
3365        if (progress)
3366                progress_state = start_progress(_("Enumerating objects"), 0);
3367        if (!use_internal_rev_list)
3368                read_object_list_from_stdin();
3369        else {
3370                get_object_list(rp.argc, rp.argv);
3371                argv_array_clear(&rp);
3372        }
3373        cleanup_preferred_base();
3374        if (include_tag && nr_result)
3375                for_each_ref(add_ref_tag, NULL);
3376        stop_progress(&progress_state);
3377
3378        if (non_empty && !nr_result)
3379                return 0;
3380        if (nr_result)
3381                prepare_pack(window, depth);
3382        write_pack_file();
3383        if (progress)
3384                fprintf_ln(stderr,
3385                           _("Total %"PRIu32" (delta %"PRIu32"),"
3386                             " reused %"PRIu32" (delta %"PRIu32")"),
3387                           written, written_delta, reused, reused_delta);
3388        return 0;
3389}