builtin / pack-objects.con commit pack-objects: refactor the packing list (2834bc2)
   1#include "builtin.h"
   2#include "cache.h"
   3#include "attr.h"
   4#include "object.h"
   5#include "blob.h"
   6#include "commit.h"
   7#include "tag.h"
   8#include "tree.h"
   9#include "delta.h"
  10#include "pack.h"
  11#include "pack-revindex.h"
  12#include "csum-file.h"
  13#include "tree-walk.h"
  14#include "diff.h"
  15#include "revision.h"
  16#include "list-objects.h"
  17#include "pack-objects.h"
  18#include "progress.h"
  19#include "refs.h"
  20#include "streaming.h"
  21#include "thread-utils.h"
  22
  23static const char *pack_usage[] = {
  24        N_("git pack-objects --stdout [options...] [< ref-list | < object-list]"),
  25        N_("git pack-objects [options...] base-name [< ref-list | < object-list]"),
  26        NULL
  27};
  28
  29/*
  30 * Objects we are going to pack are collected in the `to_pack` structure.
  31 * It contains an array (dynamically expanded) of the object data, and a map
  32 * that can resolve SHA1s to their position in the array.
  33 */
  34static struct packing_data to_pack;
  35
  36static struct pack_idx_entry **written_list;
  37static uint32_t nr_result, nr_written;
  38
  39static int non_empty;
  40static int reuse_delta = 1, reuse_object = 1;
  41static int keep_unreachable, unpack_unreachable, include_tag;
  42static unsigned long unpack_unreachable_expiration;
  43static int local;
  44static int incremental;
  45static int ignore_packed_keep;
  46static int allow_ofs_delta;
  47static struct pack_idx_option pack_idx_opts;
  48static const char *base_name;
  49static int progress = 1;
  50static int window = 10;
  51static unsigned long pack_size_limit;
  52static int depth = 50;
  53static int delta_search_threads;
  54static int pack_to_stdout;
  55static int num_preferred_base;
  56static struct progress *progress_state;
  57static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  58static int pack_compression_seen;
  59
  60static unsigned long delta_cache_size = 0;
  61static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  62static unsigned long cache_max_small_delta_size = 1000;
  63
  64static unsigned long window_memory_limit = 0;
  65
  66/*
  67 * stats
  68 */
  69static uint32_t written, written_delta;
  70static uint32_t reused, reused_delta;
  71
  72static void *get_delta(struct object_entry *entry)
  73{
  74        unsigned long size, base_size, delta_size;
  75        void *buf, *base_buf, *delta_buf;
  76        enum object_type type;
  77
  78        buf = read_sha1_file(entry->idx.sha1, &type, &size);
  79        if (!buf)
  80                die("unable to read %s", sha1_to_hex(entry->idx.sha1));
  81        base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
  82        if (!base_buf)
  83                die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
  84        delta_buf = diff_delta(base_buf, base_size,
  85                               buf, size, &delta_size, 0);
  86        if (!delta_buf || delta_size != entry->delta_size)
  87                die("delta size changed");
  88        free(buf);
  89        free(base_buf);
  90        return delta_buf;
  91}
  92
  93static unsigned long do_compress(void **pptr, unsigned long size)
  94{
  95        git_zstream stream;
  96        void *in, *out;
  97        unsigned long maxsize;
  98
  99        memset(&stream, 0, sizeof(stream));
 100        git_deflate_init(&stream, pack_compression_level);
 101        maxsize = git_deflate_bound(&stream, size);
 102
 103        in = *pptr;
 104        out = xmalloc(maxsize);
 105        *pptr = out;
 106
 107        stream.next_in = in;
 108        stream.avail_in = size;
 109        stream.next_out = out;
 110        stream.avail_out = maxsize;
 111        while (git_deflate(&stream, Z_FINISH) == Z_OK)
 112                ; /* nothing */
 113        git_deflate_end(&stream);
 114
 115        free(in);
 116        return stream.total_out;
 117}
 118
 119static unsigned long write_large_blob_data(struct git_istream *st, struct sha1file *f,
 120                                           const unsigned char *sha1)
 121{
 122        git_zstream stream;
 123        unsigned char ibuf[1024 * 16];
 124        unsigned char obuf[1024 * 16];
 125        unsigned long olen = 0;
 126
 127        memset(&stream, 0, sizeof(stream));
 128        git_deflate_init(&stream, pack_compression_level);
 129
 130        for (;;) {
 131                ssize_t readlen;
 132                int zret = Z_OK;
 133                readlen = read_istream(st, ibuf, sizeof(ibuf));
 134                if (readlen == -1)
 135                        die(_("unable to read %s"), sha1_to_hex(sha1));
 136
 137                stream.next_in = ibuf;
 138                stream.avail_in = readlen;
 139                while ((stream.avail_in || readlen == 0) &&
 140                       (zret == Z_OK || zret == Z_BUF_ERROR)) {
 141                        stream.next_out = obuf;
 142                        stream.avail_out = sizeof(obuf);
 143                        zret = git_deflate(&stream, readlen ? 0 : Z_FINISH);
 144                        sha1write(f, obuf, stream.next_out - obuf);
 145                        olen += stream.next_out - obuf;
 146                }
 147                if (stream.avail_in)
 148                        die(_("deflate error (%d)"), zret);
 149                if (readlen == 0) {
 150                        if (zret != Z_STREAM_END)
 151                                die(_("deflate error (%d)"), zret);
 152                        break;
 153                }
 154        }
 155        git_deflate_end(&stream);
 156        return olen;
 157}
 158
 159/*
 160 * we are going to reuse the existing object data as is.  make
 161 * sure it is not corrupt.
 162 */
 163static int check_pack_inflate(struct packed_git *p,
 164                struct pack_window **w_curs,
 165                off_t offset,
 166                off_t len,
 167                unsigned long expect)
 168{
 169        git_zstream stream;
 170        unsigned char fakebuf[4096], *in;
 171        int st;
 172
 173        memset(&stream, 0, sizeof(stream));
 174        git_inflate_init(&stream);
 175        do {
 176                in = use_pack(p, w_curs, offset, &stream.avail_in);
 177                stream.next_in = in;
 178                stream.next_out = fakebuf;
 179                stream.avail_out = sizeof(fakebuf);
 180                st = git_inflate(&stream, Z_FINISH);
 181                offset += stream.next_in - in;
 182        } while (st == Z_OK || st == Z_BUF_ERROR);
 183        git_inflate_end(&stream);
 184        return (st == Z_STREAM_END &&
 185                stream.total_out == expect &&
 186                stream.total_in == len) ? 0 : -1;
 187}
 188
 189static void copy_pack_data(struct sha1file *f,
 190                struct packed_git *p,
 191                struct pack_window **w_curs,
 192                off_t offset,
 193                off_t len)
 194{
 195        unsigned char *in;
 196        unsigned long avail;
 197
 198        while (len) {
 199                in = use_pack(p, w_curs, offset, &avail);
 200                if (avail > len)
 201                        avail = (unsigned long)len;
 202                sha1write(f, in, avail);
 203                offset += avail;
 204                len -= avail;
 205        }
 206}
 207
 208/* Return 0 if we will bust the pack-size limit */
 209static unsigned long write_no_reuse_object(struct sha1file *f, struct object_entry *entry,
 210                                           unsigned long limit, int usable_delta)
 211{
 212        unsigned long size, datalen;
 213        unsigned char header[10], dheader[10];
 214        unsigned hdrlen;
 215        enum object_type type;
 216        void *buf;
 217        struct git_istream *st = NULL;
 218
 219        if (!usable_delta) {
 220                if (entry->type == OBJ_BLOB &&
 221                    entry->size > big_file_threshold &&
 222                    (st = open_istream(entry->idx.sha1, &type, &size, NULL)) != NULL)
 223                        buf = NULL;
 224                else {
 225                        buf = read_sha1_file(entry->idx.sha1, &type, &size);
 226                        if (!buf)
 227                                die(_("unable to read %s"), sha1_to_hex(entry->idx.sha1));
 228                }
 229                /*
 230                 * make sure no cached delta data remains from a
 231                 * previous attempt before a pack split occurred.
 232                 */
 233                free(entry->delta_data);
 234                entry->delta_data = NULL;
 235                entry->z_delta_size = 0;
 236        } else if (entry->delta_data) {
 237                size = entry->delta_size;
 238                buf = entry->delta_data;
 239                entry->delta_data = NULL;
 240                type = (allow_ofs_delta && entry->delta->idx.offset) ?
 241                        OBJ_OFS_DELTA : OBJ_REF_DELTA;
 242        } else {
 243                buf = get_delta(entry);
 244                size = entry->delta_size;
 245                type = (allow_ofs_delta && entry->delta->idx.offset) ?
 246                        OBJ_OFS_DELTA : OBJ_REF_DELTA;
 247        }
 248
 249        if (st) /* large blob case, just assume we don't compress well */
 250                datalen = size;
 251        else if (entry->z_delta_size)
 252                datalen = entry->z_delta_size;
 253        else
 254                datalen = do_compress(&buf, size);
 255
 256        /*
 257         * The object header is a byte of 'type' followed by zero or
 258         * more bytes of length.
 259         */
 260        hdrlen = encode_in_pack_object_header(type, size, header);
 261
 262        if (type == OBJ_OFS_DELTA) {
 263                /*
 264                 * Deltas with relative base contain an additional
 265                 * encoding of the relative offset for the delta
 266                 * base from this object's position in the pack.
 267                 */
 268                off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 269                unsigned pos = sizeof(dheader) - 1;
 270                dheader[pos] = ofs & 127;
 271                while (ofs >>= 7)
 272                        dheader[--pos] = 128 | (--ofs & 127);
 273                if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 274                        if (st)
 275                                close_istream(st);
 276                        free(buf);
 277                        return 0;
 278                }
 279                sha1write(f, header, hdrlen);
 280                sha1write(f, dheader + pos, sizeof(dheader) - pos);
 281                hdrlen += sizeof(dheader) - pos;
 282        } else if (type == OBJ_REF_DELTA) {
 283                /*
 284                 * Deltas with a base reference contain
 285                 * an additional 20 bytes for the base sha1.
 286                 */
 287                if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 288                        if (st)
 289                                close_istream(st);
 290                        free(buf);
 291                        return 0;
 292                }
 293                sha1write(f, header, hdrlen);
 294                sha1write(f, entry->delta->idx.sha1, 20);
 295                hdrlen += 20;
 296        } else {
 297                if (limit && hdrlen + datalen + 20 >= limit) {
 298                        if (st)
 299                                close_istream(st);
 300                        free(buf);
 301                        return 0;
 302                }
 303                sha1write(f, header, hdrlen);
 304        }
 305        if (st) {
 306                datalen = write_large_blob_data(st, f, entry->idx.sha1);
 307                close_istream(st);
 308        } else {
 309                sha1write(f, buf, datalen);
 310                free(buf);
 311        }
 312
 313        return hdrlen + datalen;
 314}
 315
 316/* Return 0 if we will bust the pack-size limit */
 317static unsigned long write_reuse_object(struct sha1file *f, struct object_entry *entry,
 318                                        unsigned long limit, int usable_delta)
 319{
 320        struct packed_git *p = entry->in_pack;
 321        struct pack_window *w_curs = NULL;
 322        struct revindex_entry *revidx;
 323        off_t offset;
 324        enum object_type type = entry->type;
 325        unsigned long datalen;
 326        unsigned char header[10], dheader[10];
 327        unsigned hdrlen;
 328
 329        if (entry->delta)
 330                type = (allow_ofs_delta && entry->delta->idx.offset) ?
 331                        OBJ_OFS_DELTA : OBJ_REF_DELTA;
 332        hdrlen = encode_in_pack_object_header(type, entry->size, header);
 333
 334        offset = entry->in_pack_offset;
 335        revidx = find_pack_revindex(p, offset);
 336        datalen = revidx[1].offset - offset;
 337        if (!pack_to_stdout && p->index_version > 1 &&
 338            check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 339                error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 340                unuse_pack(&w_curs);
 341                return write_no_reuse_object(f, entry, limit, usable_delta);
 342        }
 343
 344        offset += entry->in_pack_header_size;
 345        datalen -= entry->in_pack_header_size;
 346
 347        if (!pack_to_stdout && p->index_version == 1 &&
 348            check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 349                error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 350                unuse_pack(&w_curs);
 351                return write_no_reuse_object(f, entry, limit, usable_delta);
 352        }
 353
 354        if (type == OBJ_OFS_DELTA) {
 355                off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 356                unsigned pos = sizeof(dheader) - 1;
 357                dheader[pos] = ofs & 127;
 358                while (ofs >>= 7)
 359                        dheader[--pos] = 128 | (--ofs & 127);
 360                if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 361                        unuse_pack(&w_curs);
 362                        return 0;
 363                }
 364                sha1write(f, header, hdrlen);
 365                sha1write(f, dheader + pos, sizeof(dheader) - pos);
 366                hdrlen += sizeof(dheader) - pos;
 367                reused_delta++;
 368        } else if (type == OBJ_REF_DELTA) {
 369                if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 370                        unuse_pack(&w_curs);
 371                        return 0;
 372                }
 373                sha1write(f, header, hdrlen);
 374                sha1write(f, entry->delta->idx.sha1, 20);
 375                hdrlen += 20;
 376                reused_delta++;
 377        } else {
 378                if (limit && hdrlen + datalen + 20 >= limit) {
 379                        unuse_pack(&w_curs);
 380                        return 0;
 381                }
 382                sha1write(f, header, hdrlen);
 383        }
 384        copy_pack_data(f, p, &w_curs, offset, datalen);
 385        unuse_pack(&w_curs);
 386        reused++;
 387        return hdrlen + datalen;
 388}
 389
 390/* Return 0 if we will bust the pack-size limit */
 391static unsigned long write_object(struct sha1file *f,
 392                                  struct object_entry *entry,
 393                                  off_t write_offset)
 394{
 395        unsigned long limit, len;
 396        int usable_delta, to_reuse;
 397
 398        if (!pack_to_stdout)
 399                crc32_begin(f);
 400
 401        /* apply size limit if limited packsize and not first object */
 402        if (!pack_size_limit || !nr_written)
 403                limit = 0;
 404        else if (pack_size_limit <= write_offset)
 405                /*
 406                 * the earlier object did not fit the limit; avoid
 407                 * mistaking this with unlimited (i.e. limit = 0).
 408                 */
 409                limit = 1;
 410        else
 411                limit = pack_size_limit - write_offset;
 412
 413        if (!entry->delta)
 414                usable_delta = 0;       /* no delta */
 415        else if (!pack_size_limit)
 416               usable_delta = 1;        /* unlimited packfile */
 417        else if (entry->delta->idx.offset == (off_t)-1)
 418                usable_delta = 0;       /* base was written to another pack */
 419        else if (entry->delta->idx.offset)
 420                usable_delta = 1;       /* base already exists in this pack */
 421        else
 422                usable_delta = 0;       /* base could end up in another pack */
 423
 424        if (!reuse_object)
 425                to_reuse = 0;   /* explicit */
 426        else if (!entry->in_pack)
 427                to_reuse = 0;   /* can't reuse what we don't have */
 428        else if (entry->type == OBJ_REF_DELTA || entry->type == OBJ_OFS_DELTA)
 429                                /* check_object() decided it for us ... */
 430                to_reuse = usable_delta;
 431                                /* ... but pack split may override that */
 432        else if (entry->type != entry->in_pack_type)
 433                to_reuse = 0;   /* pack has delta which is unusable */
 434        else if (entry->delta)
 435                to_reuse = 0;   /* we want to pack afresh */
 436        else
 437                to_reuse = 1;   /* we have it in-pack undeltified,
 438                                 * and we do not need to deltify it.
 439                                 */
 440
 441        if (!to_reuse)
 442                len = write_no_reuse_object(f, entry, limit, usable_delta);
 443        else
 444                len = write_reuse_object(f, entry, limit, usable_delta);
 445        if (!len)
 446                return 0;
 447
 448        if (usable_delta)
 449                written_delta++;
 450        written++;
 451        if (!pack_to_stdout)
 452                entry->idx.crc32 = crc32_end(f);
 453        return len;
 454}
 455
 456enum write_one_status {
 457        WRITE_ONE_SKIP = -1, /* already written */
 458        WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 459        WRITE_ONE_WRITTEN = 1, /* normal */
 460        WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 461};
 462
 463static enum write_one_status write_one(struct sha1file *f,
 464                                       struct object_entry *e,
 465                                       off_t *offset)
 466{
 467        unsigned long size;
 468        int recursing;
 469
 470        /*
 471         * we set offset to 1 (which is an impossible value) to mark
 472         * the fact that this object is involved in "write its base
 473         * first before writing a deltified object" recursion.
 474         */
 475        recursing = (e->idx.offset == 1);
 476        if (recursing) {
 477                warning("recursive delta detected for object %s",
 478                        sha1_to_hex(e->idx.sha1));
 479                return WRITE_ONE_RECURSIVE;
 480        } else if (e->idx.offset || e->preferred_base) {
 481                /* offset is non zero if object is written already. */
 482                return WRITE_ONE_SKIP;
 483        }
 484
 485        /* if we are deltified, write out base object first. */
 486        if (e->delta) {
 487                e->idx.offset = 1; /* now recurse */
 488                switch (write_one(f, e->delta, offset)) {
 489                case WRITE_ONE_RECURSIVE:
 490                        /* we cannot depend on this one */
 491                        e->delta = NULL;
 492                        break;
 493                default:
 494                        break;
 495                case WRITE_ONE_BREAK:
 496                        e->idx.offset = recursing;
 497                        return WRITE_ONE_BREAK;
 498                }
 499        }
 500
 501        e->idx.offset = *offset;
 502        size = write_object(f, e, *offset);
 503        if (!size) {
 504                e->idx.offset = recursing;
 505                return WRITE_ONE_BREAK;
 506        }
 507        written_list[nr_written++] = &e->idx;
 508
 509        /* make sure off_t is sufficiently large not to wrap */
 510        if (signed_add_overflows(*offset, size))
 511                die("pack too large for current definition of off_t");
 512        *offset += size;
 513        return WRITE_ONE_WRITTEN;
 514}
 515
 516static int mark_tagged(const char *path, const unsigned char *sha1, int flag,
 517                       void *cb_data)
 518{
 519        unsigned char peeled[20];
 520        struct object_entry *entry = packlist_find(&to_pack, sha1, NULL);
 521
 522        if (entry)
 523                entry->tagged = 1;
 524        if (!peel_ref(path, peeled)) {
 525                entry = packlist_find(&to_pack, peeled, NULL);
 526                if (entry)
 527                        entry->tagged = 1;
 528        }
 529        return 0;
 530}
 531
 532static inline void add_to_write_order(struct object_entry **wo,
 533                               unsigned int *endp,
 534                               struct object_entry *e)
 535{
 536        if (e->filled)
 537                return;
 538        wo[(*endp)++] = e;
 539        e->filled = 1;
 540}
 541
 542static void add_descendants_to_write_order(struct object_entry **wo,
 543                                           unsigned int *endp,
 544                                           struct object_entry *e)
 545{
 546        int add_to_order = 1;
 547        while (e) {
 548                if (add_to_order) {
 549                        struct object_entry *s;
 550                        /* add this node... */
 551                        add_to_write_order(wo, endp, e);
 552                        /* all its siblings... */
 553                        for (s = e->delta_sibling; s; s = s->delta_sibling) {
 554                                add_to_write_order(wo, endp, s);
 555                        }
 556                }
 557                /* drop down a level to add left subtree nodes if possible */
 558                if (e->delta_child) {
 559                        add_to_order = 1;
 560                        e = e->delta_child;
 561                } else {
 562                        add_to_order = 0;
 563                        /* our sibling might have some children, it is next */
 564                        if (e->delta_sibling) {
 565                                e = e->delta_sibling;
 566                                continue;
 567                        }
 568                        /* go back to our parent node */
 569                        e = e->delta;
 570                        while (e && !e->delta_sibling) {
 571                                /* we're on the right side of a subtree, keep
 572                                 * going up until we can go right again */
 573                                e = e->delta;
 574                        }
 575                        if (!e) {
 576                                /* done- we hit our original root node */
 577                                return;
 578                        }
 579                        /* pass it off to sibling at this level */
 580                        e = e->delta_sibling;
 581                }
 582        };
 583}
 584
 585static void add_family_to_write_order(struct object_entry **wo,
 586                                      unsigned int *endp,
 587                                      struct object_entry *e)
 588{
 589        struct object_entry *root;
 590
 591        for (root = e; root->delta; root = root->delta)
 592                ; /* nothing */
 593        add_descendants_to_write_order(wo, endp, root);
 594}
 595
 596static struct object_entry **compute_write_order(void)
 597{
 598        unsigned int i, wo_end, last_untagged;
 599
 600        struct object_entry **wo = xmalloc(to_pack.nr_objects * sizeof(*wo));
 601        struct object_entry *objects = to_pack.objects;
 602
 603        for (i = 0; i < to_pack.nr_objects; i++) {
 604                objects[i].tagged = 0;
 605                objects[i].filled = 0;
 606                objects[i].delta_child = NULL;
 607                objects[i].delta_sibling = NULL;
 608        }
 609
 610        /*
 611         * Fully connect delta_child/delta_sibling network.
 612         * Make sure delta_sibling is sorted in the original
 613         * recency order.
 614         */
 615        for (i = to_pack.nr_objects; i > 0;) {
 616                struct object_entry *e = &objects[--i];
 617                if (!e->delta)
 618                        continue;
 619                /* Mark me as the first child */
 620                e->delta_sibling = e->delta->delta_child;
 621                e->delta->delta_child = e;
 622        }
 623
 624        /*
 625         * Mark objects that are at the tip of tags.
 626         */
 627        for_each_tag_ref(mark_tagged, NULL);
 628
 629        /*
 630         * Give the objects in the original recency order until
 631         * we see a tagged tip.
 632         */
 633        for (i = wo_end = 0; i < to_pack.nr_objects; i++) {
 634                if (objects[i].tagged)
 635                        break;
 636                add_to_write_order(wo, &wo_end, &objects[i]);
 637        }
 638        last_untagged = i;
 639
 640        /*
 641         * Then fill all the tagged tips.
 642         */
 643        for (; i < to_pack.nr_objects; i++) {
 644                if (objects[i].tagged)
 645                        add_to_write_order(wo, &wo_end, &objects[i]);
 646        }
 647
 648        /*
 649         * And then all remaining commits and tags.
 650         */
 651        for (i = last_untagged; i < to_pack.nr_objects; i++) {
 652                if (objects[i].type != OBJ_COMMIT &&
 653                    objects[i].type != OBJ_TAG)
 654                        continue;
 655                add_to_write_order(wo, &wo_end, &objects[i]);
 656        }
 657
 658        /*
 659         * And then all the trees.
 660         */
 661        for (i = last_untagged; i < to_pack.nr_objects; i++) {
 662                if (objects[i].type != OBJ_TREE)
 663                        continue;
 664                add_to_write_order(wo, &wo_end, &objects[i]);
 665        }
 666
 667        /*
 668         * Finally all the rest in really tight order
 669         */
 670        for (i = last_untagged; i < to_pack.nr_objects; i++) {
 671                if (!objects[i].filled)
 672                        add_family_to_write_order(wo, &wo_end, &objects[i]);
 673        }
 674
 675        if (wo_end != to_pack.nr_objects)
 676                die("ordered %u objects, expected %"PRIu32, wo_end, to_pack.nr_objects);
 677
 678        return wo;
 679}
 680
 681static void write_pack_file(void)
 682{
 683        uint32_t i = 0, j;
 684        struct sha1file *f;
 685        off_t offset;
 686        uint32_t nr_remaining = nr_result;
 687        time_t last_mtime = 0;
 688        struct object_entry **write_order;
 689
 690        if (progress > pack_to_stdout)
 691                progress_state = start_progress("Writing objects", nr_result);
 692        written_list = xmalloc(to_pack.nr_objects * sizeof(*written_list));
 693        write_order = compute_write_order();
 694
 695        do {
 696                unsigned char sha1[20];
 697                char *pack_tmp_name = NULL;
 698
 699                if (pack_to_stdout)
 700                        f = sha1fd_throughput(1, "<stdout>", progress_state);
 701                else
 702                        f = create_tmp_packfile(&pack_tmp_name);
 703
 704                offset = write_pack_header(f, nr_remaining);
 705                if (!offset)
 706                        die_errno("unable to write pack header");
 707                nr_written = 0;
 708                for (; i < to_pack.nr_objects; i++) {
 709                        struct object_entry *e = write_order[i];
 710                        if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 711                                break;
 712                        display_progress(progress_state, written);
 713                }
 714
 715                /*
 716                 * Did we write the wrong # entries in the header?
 717                 * If so, rewrite it like in fast-import
 718                 */
 719                if (pack_to_stdout) {
 720                        sha1close(f, sha1, CSUM_CLOSE);
 721                } else if (nr_written == nr_remaining) {
 722                        sha1close(f, sha1, CSUM_FSYNC);
 723                } else {
 724                        int fd = sha1close(f, sha1, 0);
 725                        fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 726                                                 nr_written, sha1, offset);
 727                        close(fd);
 728                }
 729
 730                if (!pack_to_stdout) {
 731                        struct stat st;
 732                        char tmpname[PATH_MAX];
 733
 734                        /*
 735                         * Packs are runtime accessed in their mtime
 736                         * order since newer packs are more likely to contain
 737                         * younger objects.  So if we are creating multiple
 738                         * packs then we should modify the mtime of later ones
 739                         * to preserve this property.
 740                         */
 741                        if (stat(pack_tmp_name, &st) < 0) {
 742                                warning("failed to stat %s: %s",
 743                                        pack_tmp_name, strerror(errno));
 744                        } else if (!last_mtime) {
 745                                last_mtime = st.st_mtime;
 746                        } else {
 747                                struct utimbuf utb;
 748                                utb.actime = st.st_atime;
 749                                utb.modtime = --last_mtime;
 750                                if (utime(pack_tmp_name, &utb) < 0)
 751                                        warning("failed utime() on %s: %s",
 752                                                tmpname, strerror(errno));
 753                        }
 754
 755                        /* Enough space for "-<sha-1>.pack"? */
 756                        if (sizeof(tmpname) <= strlen(base_name) + 50)
 757                                die("pack base name '%s' too long", base_name);
 758                        snprintf(tmpname, sizeof(tmpname), "%s-", base_name);
 759                        finish_tmp_packfile(tmpname, pack_tmp_name,
 760                                            written_list, nr_written,
 761                                            &pack_idx_opts, sha1);
 762                        free(pack_tmp_name);
 763                        puts(sha1_to_hex(sha1));
 764                }
 765
 766                /* mark written objects as written to previous pack */
 767                for (j = 0; j < nr_written; j++) {
 768                        written_list[j]->offset = (off_t)-1;
 769                }
 770                nr_remaining -= nr_written;
 771        } while (nr_remaining && i < to_pack.nr_objects);
 772
 773        free(written_list);
 774        free(write_order);
 775        stop_progress(&progress_state);
 776        if (written != nr_result)
 777                die("wrote %"PRIu32" objects while expecting %"PRIu32,
 778                        written, nr_result);
 779}
 780
 781static uint32_t name_hash(const char *name)
 782{
 783        uint32_t c, hash = 0;
 784
 785        if (!name)
 786                return 0;
 787
 788        /*
 789         * This effectively just creates a sortable number from the
 790         * last sixteen non-whitespace characters. Last characters
 791         * count "most", so things that end in ".c" sort together.
 792         */
 793        while ((c = *name++) != 0) {
 794                if (isspace(c))
 795                        continue;
 796                hash = (hash >> 2) + (c << 24);
 797        }
 798        return hash;
 799}
 800
 801static void setup_delta_attr_check(struct git_attr_check *check)
 802{
 803        static struct git_attr *attr_delta;
 804
 805        if (!attr_delta)
 806                attr_delta = git_attr("delta");
 807
 808        check[0].attr = attr_delta;
 809}
 810
 811static int no_try_delta(const char *path)
 812{
 813        struct git_attr_check check[1];
 814
 815        setup_delta_attr_check(check);
 816        if (git_check_attr(path, ARRAY_SIZE(check), check))
 817                return 0;
 818        if (ATTR_FALSE(check->value))
 819                return 1;
 820        return 0;
 821}
 822
 823static int add_object_entry(const unsigned char *sha1, enum object_type type,
 824                            const char *name, int exclude)
 825{
 826        struct object_entry *entry;
 827        struct packed_git *p, *found_pack = NULL;
 828        off_t found_offset = 0;
 829        uint32_t hash = name_hash(name);
 830        uint32_t index_pos;
 831
 832        entry = packlist_find(&to_pack, sha1, &index_pos);
 833        if (entry) {
 834                if (exclude) {
 835                        if (!entry->preferred_base)
 836                                nr_result--;
 837                        entry->preferred_base = 1;
 838                }
 839                return 0;
 840        }
 841
 842        if (!exclude && local && has_loose_object_nonlocal(sha1))
 843                return 0;
 844
 845        for (p = packed_git; p; p = p->next) {
 846                off_t offset = find_pack_entry_one(sha1, p);
 847                if (offset) {
 848                        if (!found_pack) {
 849                                if (!is_pack_valid(p)) {
 850                                        warning("packfile %s cannot be accessed", p->pack_name);
 851                                        continue;
 852                                }
 853                                found_offset = offset;
 854                                found_pack = p;
 855                        }
 856                        if (exclude)
 857                                break;
 858                        if (incremental)
 859                                return 0;
 860                        if (local && !p->pack_local)
 861                                return 0;
 862                        if (ignore_packed_keep && p->pack_local && p->pack_keep)
 863                                return 0;
 864                }
 865        }
 866
 867        entry = packlist_alloc(&to_pack, sha1, index_pos);
 868        entry->hash = hash;
 869        if (type)
 870                entry->type = type;
 871        if (exclude)
 872                entry->preferred_base = 1;
 873        else
 874                nr_result++;
 875        if (found_pack) {
 876                entry->in_pack = found_pack;
 877                entry->in_pack_offset = found_offset;
 878        }
 879
 880        display_progress(progress_state, to_pack.nr_objects);
 881
 882        if (name && no_try_delta(name))
 883                entry->no_try_delta = 1;
 884
 885        return 1;
 886}
 887
 888struct pbase_tree_cache {
 889        unsigned char sha1[20];
 890        int ref;
 891        int temporary;
 892        void *tree_data;
 893        unsigned long tree_size;
 894};
 895
 896static struct pbase_tree_cache *(pbase_tree_cache[256]);
 897static int pbase_tree_cache_ix(const unsigned char *sha1)
 898{
 899        return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 900}
 901static int pbase_tree_cache_ix_incr(int ix)
 902{
 903        return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 904}
 905
 906static struct pbase_tree {
 907        struct pbase_tree *next;
 908        /* This is a phony "cache" entry; we are not
 909         * going to evict it nor find it through _get()
 910         * mechanism -- this is for the toplevel node that
 911         * would almost always change with any commit.
 912         */
 913        struct pbase_tree_cache pcache;
 914} *pbase_tree;
 915
 916static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 917{
 918        struct pbase_tree_cache *ent, *nent;
 919        void *data;
 920        unsigned long size;
 921        enum object_type type;
 922        int neigh;
 923        int my_ix = pbase_tree_cache_ix(sha1);
 924        int available_ix = -1;
 925
 926        /* pbase-tree-cache acts as a limited hashtable.
 927         * your object will be found at your index or within a few
 928         * slots after that slot if it is cached.
 929         */
 930        for (neigh = 0; neigh < 8; neigh++) {
 931                ent = pbase_tree_cache[my_ix];
 932                if (ent && !hashcmp(ent->sha1, sha1)) {
 933                        ent->ref++;
 934                        return ent;
 935                }
 936                else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 937                         ((0 <= available_ix) &&
 938                          (!ent && pbase_tree_cache[available_ix])))
 939                        available_ix = my_ix;
 940                if (!ent)
 941                        break;
 942                my_ix = pbase_tree_cache_ix_incr(my_ix);
 943        }
 944
 945        /* Did not find one.  Either we got a bogus request or
 946         * we need to read and perhaps cache.
 947         */
 948        data = read_sha1_file(sha1, &type, &size);
 949        if (!data)
 950                return NULL;
 951        if (type != OBJ_TREE) {
 952                free(data);
 953                return NULL;
 954        }
 955
 956        /* We need to either cache or return a throwaway copy */
 957
 958        if (available_ix < 0)
 959                ent = NULL;
 960        else {
 961                ent = pbase_tree_cache[available_ix];
 962                my_ix = available_ix;
 963        }
 964
 965        if (!ent) {
 966                nent = xmalloc(sizeof(*nent));
 967                nent->temporary = (available_ix < 0);
 968        }
 969        else {
 970                /* evict and reuse */
 971                free(ent->tree_data);
 972                nent = ent;
 973        }
 974        hashcpy(nent->sha1, sha1);
 975        nent->tree_data = data;
 976        nent->tree_size = size;
 977        nent->ref = 1;
 978        if (!nent->temporary)
 979                pbase_tree_cache[my_ix] = nent;
 980        return nent;
 981}
 982
 983static void pbase_tree_put(struct pbase_tree_cache *cache)
 984{
 985        if (!cache->temporary) {
 986                cache->ref--;
 987                return;
 988        }
 989        free(cache->tree_data);
 990        free(cache);
 991}
 992
 993static int name_cmp_len(const char *name)
 994{
 995        int i;
 996        for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
 997                ;
 998        return i;
 999}
1000
1001static void add_pbase_object(struct tree_desc *tree,
1002                             const char *name,
1003                             int cmplen,
1004                             const char *fullname)
1005{
1006        struct name_entry entry;
1007        int cmp;
1008
1009        while (tree_entry(tree,&entry)) {
1010                if (S_ISGITLINK(entry.mode))
1011                        continue;
1012                cmp = tree_entry_len(&entry) != cmplen ? 1 :
1013                      memcmp(name, entry.path, cmplen);
1014                if (cmp > 0)
1015                        continue;
1016                if (cmp < 0)
1017                        return;
1018                if (name[cmplen] != '/') {
1019                        add_object_entry(entry.sha1,
1020                                         object_type(entry.mode),
1021                                         fullname, 1);
1022                        return;
1023                }
1024                if (S_ISDIR(entry.mode)) {
1025                        struct tree_desc sub;
1026                        struct pbase_tree_cache *tree;
1027                        const char *down = name+cmplen+1;
1028                        int downlen = name_cmp_len(down);
1029
1030                        tree = pbase_tree_get(entry.sha1);
1031                        if (!tree)
1032                                return;
1033                        init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1034
1035                        add_pbase_object(&sub, down, downlen, fullname);
1036                        pbase_tree_put(tree);
1037                }
1038        }
1039}
1040
1041static unsigned *done_pbase_paths;
1042static int done_pbase_paths_num;
1043static int done_pbase_paths_alloc;
1044static int done_pbase_path_pos(unsigned hash)
1045{
1046        int lo = 0;
1047        int hi = done_pbase_paths_num;
1048        while (lo < hi) {
1049                int mi = (hi + lo) / 2;
1050                if (done_pbase_paths[mi] == hash)
1051                        return mi;
1052                if (done_pbase_paths[mi] < hash)
1053                        hi = mi;
1054                else
1055                        lo = mi + 1;
1056        }
1057        return -lo-1;
1058}
1059
1060static int check_pbase_path(unsigned hash)
1061{
1062        int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1063        if (0 <= pos)
1064                return 1;
1065        pos = -pos - 1;
1066        if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1067                done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1068                done_pbase_paths = xrealloc(done_pbase_paths,
1069                                            done_pbase_paths_alloc *
1070                                            sizeof(unsigned));
1071        }
1072        done_pbase_paths_num++;
1073        if (pos < done_pbase_paths_num)
1074                memmove(done_pbase_paths + pos + 1,
1075                        done_pbase_paths + pos,
1076                        (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1077        done_pbase_paths[pos] = hash;
1078        return 0;
1079}
1080
1081static void add_preferred_base_object(const char *name)
1082{
1083        struct pbase_tree *it;
1084        int cmplen;
1085        unsigned hash = name_hash(name);
1086
1087        if (!num_preferred_base || check_pbase_path(hash))
1088                return;
1089
1090        cmplen = name_cmp_len(name);
1091        for (it = pbase_tree; it; it = it->next) {
1092                if (cmplen == 0) {
1093                        add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1094                }
1095                else {
1096                        struct tree_desc tree;
1097                        init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1098                        add_pbase_object(&tree, name, cmplen, name);
1099                }
1100        }
1101}
1102
1103static void add_preferred_base(unsigned char *sha1)
1104{
1105        struct pbase_tree *it;
1106        void *data;
1107        unsigned long size;
1108        unsigned char tree_sha1[20];
1109
1110        if (window <= num_preferred_base++)
1111                return;
1112
1113        data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1114        if (!data)
1115                return;
1116
1117        for (it = pbase_tree; it; it = it->next) {
1118                if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1119                        free(data);
1120                        return;
1121                }
1122        }
1123
1124        it = xcalloc(1, sizeof(*it));
1125        it->next = pbase_tree;
1126        pbase_tree = it;
1127
1128        hashcpy(it->pcache.sha1, tree_sha1);
1129        it->pcache.tree_data = data;
1130        it->pcache.tree_size = size;
1131}
1132
1133static void cleanup_preferred_base(void)
1134{
1135        struct pbase_tree *it;
1136        unsigned i;
1137
1138        it = pbase_tree;
1139        pbase_tree = NULL;
1140        while (it) {
1141                struct pbase_tree *this = it;
1142                it = this->next;
1143                free(this->pcache.tree_data);
1144                free(this);
1145        }
1146
1147        for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1148                if (!pbase_tree_cache[i])
1149                        continue;
1150                free(pbase_tree_cache[i]->tree_data);
1151                free(pbase_tree_cache[i]);
1152                pbase_tree_cache[i] = NULL;
1153        }
1154
1155        free(done_pbase_paths);
1156        done_pbase_paths = NULL;
1157        done_pbase_paths_num = done_pbase_paths_alloc = 0;
1158}
1159
1160static void check_object(struct object_entry *entry)
1161{
1162        if (entry->in_pack) {
1163                struct packed_git *p = entry->in_pack;
1164                struct pack_window *w_curs = NULL;
1165                const unsigned char *base_ref = NULL;
1166                struct object_entry *base_entry;
1167                unsigned long used, used_0;
1168                unsigned long avail;
1169                off_t ofs;
1170                unsigned char *buf, c;
1171
1172                buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1173
1174                /*
1175                 * We want in_pack_type even if we do not reuse delta
1176                 * since non-delta representations could still be reused.
1177                 */
1178                used = unpack_object_header_buffer(buf, avail,
1179                                                   &entry->in_pack_type,
1180                                                   &entry->size);
1181                if (used == 0)
1182                        goto give_up;
1183
1184                /*
1185                 * Determine if this is a delta and if so whether we can
1186                 * reuse it or not.  Otherwise let's find out as cheaply as
1187                 * possible what the actual type and size for this object is.
1188                 */
1189                switch (entry->in_pack_type) {
1190                default:
1191                        /* Not a delta hence we've already got all we need. */
1192                        entry->type = entry->in_pack_type;
1193                        entry->in_pack_header_size = used;
1194                        if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1195                                goto give_up;
1196                        unuse_pack(&w_curs);
1197                        return;
1198                case OBJ_REF_DELTA:
1199                        if (reuse_delta && !entry->preferred_base)
1200                                base_ref = use_pack(p, &w_curs,
1201                                                entry->in_pack_offset + used, NULL);
1202                        entry->in_pack_header_size = used + 20;
1203                        break;
1204                case OBJ_OFS_DELTA:
1205                        buf = use_pack(p, &w_curs,
1206                                       entry->in_pack_offset + used, NULL);
1207                        used_0 = 0;
1208                        c = buf[used_0++];
1209                        ofs = c & 127;
1210                        while (c & 128) {
1211                                ofs += 1;
1212                                if (!ofs || MSB(ofs, 7)) {
1213                                        error("delta base offset overflow in pack for %s",
1214                                              sha1_to_hex(entry->idx.sha1));
1215                                        goto give_up;
1216                                }
1217                                c = buf[used_0++];
1218                                ofs = (ofs << 7) + (c & 127);
1219                        }
1220                        ofs = entry->in_pack_offset - ofs;
1221                        if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1222                                error("delta base offset out of bound for %s",
1223                                      sha1_to_hex(entry->idx.sha1));
1224                                goto give_up;
1225                        }
1226                        if (reuse_delta && !entry->preferred_base) {
1227                                struct revindex_entry *revidx;
1228                                revidx = find_pack_revindex(p, ofs);
1229                                if (!revidx)
1230                                        goto give_up;
1231                                base_ref = nth_packed_object_sha1(p, revidx->nr);
1232                        }
1233                        entry->in_pack_header_size = used + used_0;
1234                        break;
1235                }
1236
1237                if (base_ref && (base_entry = packlist_find(&to_pack, base_ref, NULL))) {
1238                        /*
1239                         * If base_ref was set above that means we wish to
1240                         * reuse delta data, and we even found that base
1241                         * in the list of objects we want to pack. Goodie!
1242                         *
1243                         * Depth value does not matter - find_deltas() will
1244                         * never consider reused delta as the base object to
1245                         * deltify other objects against, in order to avoid
1246                         * circular deltas.
1247                         */
1248                        entry->type = entry->in_pack_type;
1249                        entry->delta = base_entry;
1250                        entry->delta_size = entry->size;
1251                        entry->delta_sibling = base_entry->delta_child;
1252                        base_entry->delta_child = entry;
1253                        unuse_pack(&w_curs);
1254                        return;
1255                }
1256
1257                if (entry->type) {
1258                        /*
1259                         * This must be a delta and we already know what the
1260                         * final object type is.  Let's extract the actual
1261                         * object size from the delta header.
1262                         */
1263                        entry->size = get_size_from_delta(p, &w_curs,
1264                                        entry->in_pack_offset + entry->in_pack_header_size);
1265                        if (entry->size == 0)
1266                                goto give_up;
1267                        unuse_pack(&w_curs);
1268                        return;
1269                }
1270
1271                /*
1272                 * No choice but to fall back to the recursive delta walk
1273                 * with sha1_object_info() to find about the object type
1274                 * at this point...
1275                 */
1276                give_up:
1277                unuse_pack(&w_curs);
1278        }
1279
1280        entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1281        /*
1282         * The error condition is checked in prepare_pack().  This is
1283         * to permit a missing preferred base object to be ignored
1284         * as a preferred base.  Doing so can result in a larger
1285         * pack file, but the transfer will still take place.
1286         */
1287}
1288
1289static int pack_offset_sort(const void *_a, const void *_b)
1290{
1291        const struct object_entry *a = *(struct object_entry **)_a;
1292        const struct object_entry *b = *(struct object_entry **)_b;
1293
1294        /* avoid filesystem trashing with loose objects */
1295        if (!a->in_pack && !b->in_pack)
1296                return hashcmp(a->idx.sha1, b->idx.sha1);
1297
1298        if (a->in_pack < b->in_pack)
1299                return -1;
1300        if (a->in_pack > b->in_pack)
1301                return 1;
1302        return a->in_pack_offset < b->in_pack_offset ? -1 :
1303                        (a->in_pack_offset > b->in_pack_offset);
1304}
1305
1306static void get_object_details(void)
1307{
1308        uint32_t i;
1309        struct object_entry **sorted_by_offset;
1310
1311        sorted_by_offset = xcalloc(to_pack.nr_objects, sizeof(struct object_entry *));
1312        for (i = 0; i < to_pack.nr_objects; i++)
1313                sorted_by_offset[i] = to_pack.objects + i;
1314        qsort(sorted_by_offset, to_pack.nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1315
1316        for (i = 0; i < to_pack.nr_objects; i++) {
1317                struct object_entry *entry = sorted_by_offset[i];
1318                check_object(entry);
1319                if (big_file_threshold < entry->size)
1320                        entry->no_try_delta = 1;
1321        }
1322
1323        free(sorted_by_offset);
1324}
1325
1326/*
1327 * We search for deltas in a list sorted by type, by filename hash, and then
1328 * by size, so that we see progressively smaller and smaller files.
1329 * That's because we prefer deltas to be from the bigger file
1330 * to the smaller -- deletes are potentially cheaper, but perhaps
1331 * more importantly, the bigger file is likely the more recent
1332 * one.  The deepest deltas are therefore the oldest objects which are
1333 * less susceptible to be accessed often.
1334 */
1335static int type_size_sort(const void *_a, const void *_b)
1336{
1337        const struct object_entry *a = *(struct object_entry **)_a;
1338        const struct object_entry *b = *(struct object_entry **)_b;
1339
1340        if (a->type > b->type)
1341                return -1;
1342        if (a->type < b->type)
1343                return 1;
1344        if (a->hash > b->hash)
1345                return -1;
1346        if (a->hash < b->hash)
1347                return 1;
1348        if (a->preferred_base > b->preferred_base)
1349                return -1;
1350        if (a->preferred_base < b->preferred_base)
1351                return 1;
1352        if (a->size > b->size)
1353                return -1;
1354        if (a->size < b->size)
1355                return 1;
1356        return a < b ? -1 : (a > b);  /* newest first */
1357}
1358
1359struct unpacked {
1360        struct object_entry *entry;
1361        void *data;
1362        struct delta_index *index;
1363        unsigned depth;
1364};
1365
1366static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1367                           unsigned long delta_size)
1368{
1369        if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1370                return 0;
1371
1372        if (delta_size < cache_max_small_delta_size)
1373                return 1;
1374
1375        /* cache delta, if objects are large enough compared to delta size */
1376        if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1377                return 1;
1378
1379        return 0;
1380}
1381
1382#ifndef NO_PTHREADS
1383
1384static pthread_mutex_t read_mutex;
1385#define read_lock()             pthread_mutex_lock(&read_mutex)
1386#define read_unlock()           pthread_mutex_unlock(&read_mutex)
1387
1388static pthread_mutex_t cache_mutex;
1389#define cache_lock()            pthread_mutex_lock(&cache_mutex)
1390#define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1391
1392static pthread_mutex_t progress_mutex;
1393#define progress_lock()         pthread_mutex_lock(&progress_mutex)
1394#define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1395
1396#else
1397
1398#define read_lock()             (void)0
1399#define read_unlock()           (void)0
1400#define cache_lock()            (void)0
1401#define cache_unlock()          (void)0
1402#define progress_lock()         (void)0
1403#define progress_unlock()       (void)0
1404
1405#endif
1406
1407static int try_delta(struct unpacked *trg, struct unpacked *src,
1408                     unsigned max_depth, unsigned long *mem_usage)
1409{
1410        struct object_entry *trg_entry = trg->entry;
1411        struct object_entry *src_entry = src->entry;
1412        unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1413        unsigned ref_depth;
1414        enum object_type type;
1415        void *delta_buf;
1416
1417        /* Don't bother doing diffs between different types */
1418        if (trg_entry->type != src_entry->type)
1419                return -1;
1420
1421        /*
1422         * We do not bother to try a delta that we discarded on an
1423         * earlier try, but only when reusing delta data.  Note that
1424         * src_entry that is marked as the preferred_base should always
1425         * be considered, as even if we produce a suboptimal delta against
1426         * it, we will still save the transfer cost, as we already know
1427         * the other side has it and we won't send src_entry at all.
1428         */
1429        if (reuse_delta && trg_entry->in_pack &&
1430            trg_entry->in_pack == src_entry->in_pack &&
1431            !src_entry->preferred_base &&
1432            trg_entry->in_pack_type != OBJ_REF_DELTA &&
1433            trg_entry->in_pack_type != OBJ_OFS_DELTA)
1434                return 0;
1435
1436        /* Let's not bust the allowed depth. */
1437        if (src->depth >= max_depth)
1438                return 0;
1439
1440        /* Now some size filtering heuristics. */
1441        trg_size = trg_entry->size;
1442        if (!trg_entry->delta) {
1443                max_size = trg_size/2 - 20;
1444                ref_depth = 1;
1445        } else {
1446                max_size = trg_entry->delta_size;
1447                ref_depth = trg->depth;
1448        }
1449        max_size = (uint64_t)max_size * (max_depth - src->depth) /
1450                                                (max_depth - ref_depth + 1);
1451        if (max_size == 0)
1452                return 0;
1453        src_size = src_entry->size;
1454        sizediff = src_size < trg_size ? trg_size - src_size : 0;
1455        if (sizediff >= max_size)
1456                return 0;
1457        if (trg_size < src_size / 32)
1458                return 0;
1459
1460        /* Load data if not already done */
1461        if (!trg->data) {
1462                read_lock();
1463                trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1464                read_unlock();
1465                if (!trg->data)
1466                        die("object %s cannot be read",
1467                            sha1_to_hex(trg_entry->idx.sha1));
1468                if (sz != trg_size)
1469                        die("object %s inconsistent object length (%lu vs %lu)",
1470                            sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1471                *mem_usage += sz;
1472        }
1473        if (!src->data) {
1474                read_lock();
1475                src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1476                read_unlock();
1477                if (!src->data) {
1478                        if (src_entry->preferred_base) {
1479                                static int warned = 0;
1480                                if (!warned++)
1481                                        warning("object %s cannot be read",
1482                                                sha1_to_hex(src_entry->idx.sha1));
1483                                /*
1484                                 * Those objects are not included in the
1485                                 * resulting pack.  Be resilient and ignore
1486                                 * them if they can't be read, in case the
1487                                 * pack could be created nevertheless.
1488                                 */
1489                                return 0;
1490                        }
1491                        die("object %s cannot be read",
1492                            sha1_to_hex(src_entry->idx.sha1));
1493                }
1494                if (sz != src_size)
1495                        die("object %s inconsistent object length (%lu vs %lu)",
1496                            sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1497                *mem_usage += sz;
1498        }
1499        if (!src->index) {
1500                src->index = create_delta_index(src->data, src_size);
1501                if (!src->index) {
1502                        static int warned = 0;
1503                        if (!warned++)
1504                                warning("suboptimal pack - out of memory");
1505                        return 0;
1506                }
1507                *mem_usage += sizeof_delta_index(src->index);
1508        }
1509
1510        delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1511        if (!delta_buf)
1512                return 0;
1513
1514        if (trg_entry->delta) {
1515                /* Prefer only shallower same-sized deltas. */
1516                if (delta_size == trg_entry->delta_size &&
1517                    src->depth + 1 >= trg->depth) {
1518                        free(delta_buf);
1519                        return 0;
1520                }
1521        }
1522
1523        /*
1524         * Handle memory allocation outside of the cache
1525         * accounting lock.  Compiler will optimize the strangeness
1526         * away when NO_PTHREADS is defined.
1527         */
1528        free(trg_entry->delta_data);
1529        cache_lock();
1530        if (trg_entry->delta_data) {
1531                delta_cache_size -= trg_entry->delta_size;
1532                trg_entry->delta_data = NULL;
1533        }
1534        if (delta_cacheable(src_size, trg_size, delta_size)) {
1535                delta_cache_size += delta_size;
1536                cache_unlock();
1537                trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1538        } else {
1539                cache_unlock();
1540                free(delta_buf);
1541        }
1542
1543        trg_entry->delta = src_entry;
1544        trg_entry->delta_size = delta_size;
1545        trg->depth = src->depth + 1;
1546
1547        return 1;
1548}
1549
1550static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1551{
1552        struct object_entry *child = me->delta_child;
1553        unsigned int m = n;
1554        while (child) {
1555                unsigned int c = check_delta_limit(child, n + 1);
1556                if (m < c)
1557                        m = c;
1558                child = child->delta_sibling;
1559        }
1560        return m;
1561}
1562
1563static unsigned long free_unpacked(struct unpacked *n)
1564{
1565        unsigned long freed_mem = sizeof_delta_index(n->index);
1566        free_delta_index(n->index);
1567        n->index = NULL;
1568        if (n->data) {
1569                freed_mem += n->entry->size;
1570                free(n->data);
1571                n->data = NULL;
1572        }
1573        n->entry = NULL;
1574        n->depth = 0;
1575        return freed_mem;
1576}
1577
1578static void find_deltas(struct object_entry **list, unsigned *list_size,
1579                        int window, int depth, unsigned *processed)
1580{
1581        uint32_t i, idx = 0, count = 0;
1582        struct unpacked *array;
1583        unsigned long mem_usage = 0;
1584
1585        array = xcalloc(window, sizeof(struct unpacked));
1586
1587        for (;;) {
1588                struct object_entry *entry;
1589                struct unpacked *n = array + idx;
1590                int j, max_depth, best_base = -1;
1591
1592                progress_lock();
1593                if (!*list_size) {
1594                        progress_unlock();
1595                        break;
1596                }
1597                entry = *list++;
1598                (*list_size)--;
1599                if (!entry->preferred_base) {
1600                        (*processed)++;
1601                        display_progress(progress_state, *processed);
1602                }
1603                progress_unlock();
1604
1605                mem_usage -= free_unpacked(n);
1606                n->entry = entry;
1607
1608                while (window_memory_limit &&
1609                       mem_usage > window_memory_limit &&
1610                       count > 1) {
1611                        uint32_t tail = (idx + window - count) % window;
1612                        mem_usage -= free_unpacked(array + tail);
1613                        count--;
1614                }
1615
1616                /* We do not compute delta to *create* objects we are not
1617                 * going to pack.
1618                 */
1619                if (entry->preferred_base)
1620                        goto next;
1621
1622                /*
1623                 * If the current object is at pack edge, take the depth the
1624                 * objects that depend on the current object into account
1625                 * otherwise they would become too deep.
1626                 */
1627                max_depth = depth;
1628                if (entry->delta_child) {
1629                        max_depth -= check_delta_limit(entry, 0);
1630                        if (max_depth <= 0)
1631                                goto next;
1632                }
1633
1634                j = window;
1635                while (--j > 0) {
1636                        int ret;
1637                        uint32_t other_idx = idx + j;
1638                        struct unpacked *m;
1639                        if (other_idx >= window)
1640                                other_idx -= window;
1641                        m = array + other_idx;
1642                        if (!m->entry)
1643                                break;
1644                        ret = try_delta(n, m, max_depth, &mem_usage);
1645                        if (ret < 0)
1646                                break;
1647                        else if (ret > 0)
1648                                best_base = other_idx;
1649                }
1650
1651                /*
1652                 * If we decided to cache the delta data, then it is best
1653                 * to compress it right away.  First because we have to do
1654                 * it anyway, and doing it here while we're threaded will
1655                 * save a lot of time in the non threaded write phase,
1656                 * as well as allow for caching more deltas within
1657                 * the same cache size limit.
1658                 * ...
1659                 * But only if not writing to stdout, since in that case
1660                 * the network is most likely throttling writes anyway,
1661                 * and therefore it is best to go to the write phase ASAP
1662                 * instead, as we can afford spending more time compressing
1663                 * between writes at that moment.
1664                 */
1665                if (entry->delta_data && !pack_to_stdout) {
1666                        entry->z_delta_size = do_compress(&entry->delta_data,
1667                                                          entry->delta_size);
1668                        cache_lock();
1669                        delta_cache_size -= entry->delta_size;
1670                        delta_cache_size += entry->z_delta_size;
1671                        cache_unlock();
1672                }
1673
1674                /* if we made n a delta, and if n is already at max
1675                 * depth, leaving it in the window is pointless.  we
1676                 * should evict it first.
1677                 */
1678                if (entry->delta && max_depth <= n->depth)
1679                        continue;
1680
1681                /*
1682                 * Move the best delta base up in the window, after the
1683                 * currently deltified object, to keep it longer.  It will
1684                 * be the first base object to be attempted next.
1685                 */
1686                if (entry->delta) {
1687                        struct unpacked swap = array[best_base];
1688                        int dist = (window + idx - best_base) % window;
1689                        int dst = best_base;
1690                        while (dist--) {
1691                                int src = (dst + 1) % window;
1692                                array[dst] = array[src];
1693                                dst = src;
1694                        }
1695                        array[dst] = swap;
1696                }
1697
1698                next:
1699                idx++;
1700                if (count + 1 < window)
1701                        count++;
1702                if (idx >= window)
1703                        idx = 0;
1704        }
1705
1706        for (i = 0; i < window; ++i) {
1707                free_delta_index(array[i].index);
1708                free(array[i].data);
1709        }
1710        free(array);
1711}
1712
1713#ifndef NO_PTHREADS
1714
1715static void try_to_free_from_threads(size_t size)
1716{
1717        read_lock();
1718        release_pack_memory(size);
1719        read_unlock();
1720}
1721
1722static try_to_free_t old_try_to_free_routine;
1723
1724/*
1725 * The main thread waits on the condition that (at least) one of the workers
1726 * has stopped working (which is indicated in the .working member of
1727 * struct thread_params).
1728 * When a work thread has completed its work, it sets .working to 0 and
1729 * signals the main thread and waits on the condition that .data_ready
1730 * becomes 1.
1731 */
1732
1733struct thread_params {
1734        pthread_t thread;
1735        struct object_entry **list;
1736        unsigned list_size;
1737        unsigned remaining;
1738        int window;
1739        int depth;
1740        int working;
1741        int data_ready;
1742        pthread_mutex_t mutex;
1743        pthread_cond_t cond;
1744        unsigned *processed;
1745};
1746
1747static pthread_cond_t progress_cond;
1748
1749/*
1750 * Mutex and conditional variable can't be statically-initialized on Windows.
1751 */
1752static void init_threaded_search(void)
1753{
1754        init_recursive_mutex(&read_mutex);
1755        pthread_mutex_init(&cache_mutex, NULL);
1756        pthread_mutex_init(&progress_mutex, NULL);
1757        pthread_cond_init(&progress_cond, NULL);
1758        old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
1759}
1760
1761static void cleanup_threaded_search(void)
1762{
1763        set_try_to_free_routine(old_try_to_free_routine);
1764        pthread_cond_destroy(&progress_cond);
1765        pthread_mutex_destroy(&read_mutex);
1766        pthread_mutex_destroy(&cache_mutex);
1767        pthread_mutex_destroy(&progress_mutex);
1768}
1769
1770static void *threaded_find_deltas(void *arg)
1771{
1772        struct thread_params *me = arg;
1773
1774        while (me->remaining) {
1775                find_deltas(me->list, &me->remaining,
1776                            me->window, me->depth, me->processed);
1777
1778                progress_lock();
1779                me->working = 0;
1780                pthread_cond_signal(&progress_cond);
1781                progress_unlock();
1782
1783                /*
1784                 * We must not set ->data_ready before we wait on the
1785                 * condition because the main thread may have set it to 1
1786                 * before we get here. In order to be sure that new
1787                 * work is available if we see 1 in ->data_ready, it
1788                 * was initialized to 0 before this thread was spawned
1789                 * and we reset it to 0 right away.
1790                 */
1791                pthread_mutex_lock(&me->mutex);
1792                while (!me->data_ready)
1793                        pthread_cond_wait(&me->cond, &me->mutex);
1794                me->data_ready = 0;
1795                pthread_mutex_unlock(&me->mutex);
1796        }
1797        /* leave ->working 1 so that this doesn't get more work assigned */
1798        return NULL;
1799}
1800
1801static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1802                           int window, int depth, unsigned *processed)
1803{
1804        struct thread_params *p;
1805        int i, ret, active_threads = 0;
1806
1807        init_threaded_search();
1808
1809        if (!delta_search_threads)      /* --threads=0 means autodetect */
1810                delta_search_threads = online_cpus();
1811        if (delta_search_threads <= 1) {
1812                find_deltas(list, &list_size, window, depth, processed);
1813                cleanup_threaded_search();
1814                return;
1815        }
1816        if (progress > pack_to_stdout)
1817                fprintf(stderr, "Delta compression using up to %d threads.\n",
1818                                delta_search_threads);
1819        p = xcalloc(delta_search_threads, sizeof(*p));
1820
1821        /* Partition the work amongst work threads. */
1822        for (i = 0; i < delta_search_threads; i++) {
1823                unsigned sub_size = list_size / (delta_search_threads - i);
1824
1825                /* don't use too small segments or no deltas will be found */
1826                if (sub_size < 2*window && i+1 < delta_search_threads)
1827                        sub_size = 0;
1828
1829                p[i].window = window;
1830                p[i].depth = depth;
1831                p[i].processed = processed;
1832                p[i].working = 1;
1833                p[i].data_ready = 0;
1834
1835                /* try to split chunks on "path" boundaries */
1836                while (sub_size && sub_size < list_size &&
1837                       list[sub_size]->hash &&
1838                       list[sub_size]->hash == list[sub_size-1]->hash)
1839                        sub_size++;
1840
1841                p[i].list = list;
1842                p[i].list_size = sub_size;
1843                p[i].remaining = sub_size;
1844
1845                list += sub_size;
1846                list_size -= sub_size;
1847        }
1848
1849        /* Start work threads. */
1850        for (i = 0; i < delta_search_threads; i++) {
1851                if (!p[i].list_size)
1852                        continue;
1853                pthread_mutex_init(&p[i].mutex, NULL);
1854                pthread_cond_init(&p[i].cond, NULL);
1855                ret = pthread_create(&p[i].thread, NULL,
1856                                     threaded_find_deltas, &p[i]);
1857                if (ret)
1858                        die("unable to create thread: %s", strerror(ret));
1859                active_threads++;
1860        }
1861
1862        /*
1863         * Now let's wait for work completion.  Each time a thread is done
1864         * with its work, we steal half of the remaining work from the
1865         * thread with the largest number of unprocessed objects and give
1866         * it to that newly idle thread.  This ensure good load balancing
1867         * until the remaining object list segments are simply too short
1868         * to be worth splitting anymore.
1869         */
1870        while (active_threads) {
1871                struct thread_params *target = NULL;
1872                struct thread_params *victim = NULL;
1873                unsigned sub_size = 0;
1874
1875                progress_lock();
1876                for (;;) {
1877                        for (i = 0; !target && i < delta_search_threads; i++)
1878                                if (!p[i].working)
1879                                        target = &p[i];
1880                        if (target)
1881                                break;
1882                        pthread_cond_wait(&progress_cond, &progress_mutex);
1883                }
1884
1885                for (i = 0; i < delta_search_threads; i++)
1886                        if (p[i].remaining > 2*window &&
1887                            (!victim || victim->remaining < p[i].remaining))
1888                                victim = &p[i];
1889                if (victim) {
1890                        sub_size = victim->remaining / 2;
1891                        list = victim->list + victim->list_size - sub_size;
1892                        while (sub_size && list[0]->hash &&
1893                               list[0]->hash == list[-1]->hash) {
1894                                list++;
1895                                sub_size--;
1896                        }
1897                        if (!sub_size) {
1898                                /*
1899                                 * It is possible for some "paths" to have
1900                                 * so many objects that no hash boundary
1901                                 * might be found.  Let's just steal the
1902                                 * exact half in that case.
1903                                 */
1904                                sub_size = victim->remaining / 2;
1905                                list -= sub_size;
1906                        }
1907                        target->list = list;
1908                        victim->list_size -= sub_size;
1909                        victim->remaining -= sub_size;
1910                }
1911                target->list_size = sub_size;
1912                target->remaining = sub_size;
1913                target->working = 1;
1914                progress_unlock();
1915
1916                pthread_mutex_lock(&target->mutex);
1917                target->data_ready = 1;
1918                pthread_cond_signal(&target->cond);
1919                pthread_mutex_unlock(&target->mutex);
1920
1921                if (!sub_size) {
1922                        pthread_join(target->thread, NULL);
1923                        pthread_cond_destroy(&target->cond);
1924                        pthread_mutex_destroy(&target->mutex);
1925                        active_threads--;
1926                }
1927        }
1928        cleanup_threaded_search();
1929        free(p);
1930}
1931
1932#else
1933#define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
1934#endif
1935
1936static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1937{
1938        unsigned char peeled[20];
1939
1940        if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
1941            !peel_ref(path, peeled)        && /* peelable? */
1942            packlist_find(&to_pack, peeled, NULL))      /* object packed? */
1943                add_object_entry(sha1, OBJ_TAG, NULL, 0);
1944        return 0;
1945}
1946
1947static void prepare_pack(int window, int depth)
1948{
1949        struct object_entry **delta_list;
1950        uint32_t i, nr_deltas;
1951        unsigned n;
1952
1953        get_object_details();
1954
1955        /*
1956         * If we're locally repacking then we need to be doubly careful
1957         * from now on in order to make sure no stealth corruption gets
1958         * propagated to the new pack.  Clients receiving streamed packs
1959         * should validate everything they get anyway so no need to incur
1960         * the additional cost here in that case.
1961         */
1962        if (!pack_to_stdout)
1963                do_check_packed_object_crc = 1;
1964
1965        if (!to_pack.nr_objects || !window || !depth)
1966                return;
1967
1968        delta_list = xmalloc(to_pack.nr_objects * sizeof(*delta_list));
1969        nr_deltas = n = 0;
1970
1971        for (i = 0; i < to_pack.nr_objects; i++) {
1972                struct object_entry *entry = to_pack.objects + i;
1973
1974                if (entry->delta)
1975                        /* This happens if we decided to reuse existing
1976                         * delta from a pack.  "reuse_delta &&" is implied.
1977                         */
1978                        continue;
1979
1980                if (entry->size < 50)
1981                        continue;
1982
1983                if (entry->no_try_delta)
1984                        continue;
1985
1986                if (!entry->preferred_base) {
1987                        nr_deltas++;
1988                        if (entry->type < 0)
1989                                die("unable to get type of object %s",
1990                                    sha1_to_hex(entry->idx.sha1));
1991                } else {
1992                        if (entry->type < 0) {
1993                                /*
1994                                 * This object is not found, but we
1995                                 * don't have to include it anyway.
1996                                 */
1997                                continue;
1998                        }
1999                }
2000
2001                delta_list[n++] = entry;
2002        }
2003
2004        if (nr_deltas && n > 1) {
2005                unsigned nr_done = 0;
2006                if (progress)
2007                        progress_state = start_progress("Compressing objects",
2008                                                        nr_deltas);
2009                qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
2010                ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2011                stop_progress(&progress_state);
2012                if (nr_done != nr_deltas)
2013                        die("inconsistency with delta count");
2014        }
2015        free(delta_list);
2016}
2017
2018static int git_pack_config(const char *k, const char *v, void *cb)
2019{
2020        if (!strcmp(k, "pack.window")) {
2021                window = git_config_int(k, v);
2022                return 0;
2023        }
2024        if (!strcmp(k, "pack.windowmemory")) {
2025                window_memory_limit = git_config_ulong(k, v);
2026                return 0;
2027        }
2028        if (!strcmp(k, "pack.depth")) {
2029                depth = git_config_int(k, v);
2030                return 0;
2031        }
2032        if (!strcmp(k, "pack.compression")) {
2033                int level = git_config_int(k, v);
2034                if (level == -1)
2035                        level = Z_DEFAULT_COMPRESSION;
2036                else if (level < 0 || level > Z_BEST_COMPRESSION)
2037                        die("bad pack compression level %d", level);
2038                pack_compression_level = level;
2039                pack_compression_seen = 1;
2040                return 0;
2041        }
2042        if (!strcmp(k, "pack.deltacachesize")) {
2043                max_delta_cache_size = git_config_int(k, v);
2044                return 0;
2045        }
2046        if (!strcmp(k, "pack.deltacachelimit")) {
2047                cache_max_small_delta_size = git_config_int(k, v);
2048                return 0;
2049        }
2050        if (!strcmp(k, "pack.threads")) {
2051                delta_search_threads = git_config_int(k, v);
2052                if (delta_search_threads < 0)
2053                        die("invalid number of threads specified (%d)",
2054                            delta_search_threads);
2055#ifdef NO_PTHREADS
2056                if (delta_search_threads != 1)
2057                        warning("no threads support, ignoring %s", k);
2058#endif
2059                return 0;
2060        }
2061        if (!strcmp(k, "pack.indexversion")) {
2062                pack_idx_opts.version = git_config_int(k, v);
2063                if (pack_idx_opts.version > 2)
2064                        die("bad pack.indexversion=%"PRIu32,
2065                            pack_idx_opts.version);
2066                return 0;
2067        }
2068        return git_default_config(k, v, cb);
2069}
2070
2071static void read_object_list_from_stdin(void)
2072{
2073        char line[40 + 1 + PATH_MAX + 2];
2074        unsigned char sha1[20];
2075
2076        for (;;) {
2077                if (!fgets(line, sizeof(line), stdin)) {
2078                        if (feof(stdin))
2079                                break;
2080                        if (!ferror(stdin))
2081                                die("fgets returned NULL, not EOF, not error!");
2082                        if (errno != EINTR)
2083                                die_errno("fgets");
2084                        clearerr(stdin);
2085                        continue;
2086                }
2087                if (line[0] == '-') {
2088                        if (get_sha1_hex(line+1, sha1))
2089                                die("expected edge sha1, got garbage:\n %s",
2090                                    line);
2091                        add_preferred_base(sha1);
2092                        continue;
2093                }
2094                if (get_sha1_hex(line, sha1))
2095                        die("expected sha1, got garbage:\n %s", line);
2096
2097                add_preferred_base_object(line+41);
2098                add_object_entry(sha1, 0, line+41, 0);
2099        }
2100}
2101
2102#define OBJECT_ADDED (1u<<20)
2103
2104static void show_commit(struct commit *commit, void *data)
2105{
2106        add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
2107        commit->object.flags |= OBJECT_ADDED;
2108}
2109
2110static void show_object(struct object *obj,
2111                        const struct name_path *path, const char *last,
2112                        void *data)
2113{
2114        char *name = path_name(path, last);
2115
2116        add_preferred_base_object(name);
2117        add_object_entry(obj->sha1, obj->type, name, 0);
2118        obj->flags |= OBJECT_ADDED;
2119
2120        /*
2121         * We will have generated the hash from the name,
2122         * but not saved a pointer to it - we can free it
2123         */
2124        free((char *)name);
2125}
2126
2127static void show_edge(struct commit *commit)
2128{
2129        add_preferred_base(commit->object.sha1);
2130}
2131
2132struct in_pack_object {
2133        off_t offset;
2134        struct object *object;
2135};
2136
2137struct in_pack {
2138        int alloc;
2139        int nr;
2140        struct in_pack_object *array;
2141};
2142
2143static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2144{
2145        in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
2146        in_pack->array[in_pack->nr].object = object;
2147        in_pack->nr++;
2148}
2149
2150/*
2151 * Compare the objects in the offset order, in order to emulate the
2152 * "git rev-list --objects" output that produced the pack originally.
2153 */
2154static int ofscmp(const void *a_, const void *b_)
2155{
2156        struct in_pack_object *a = (struct in_pack_object *)a_;
2157        struct in_pack_object *b = (struct in_pack_object *)b_;
2158
2159        if (a->offset < b->offset)
2160                return -1;
2161        else if (a->offset > b->offset)
2162                return 1;
2163        else
2164                return hashcmp(a->object->sha1, b->object->sha1);
2165}
2166
2167static void add_objects_in_unpacked_packs(struct rev_info *revs)
2168{
2169        struct packed_git *p;
2170        struct in_pack in_pack;
2171        uint32_t i;
2172
2173        memset(&in_pack, 0, sizeof(in_pack));
2174
2175        for (p = packed_git; p; p = p->next) {
2176                const unsigned char *sha1;
2177                struct object *o;
2178
2179                if (!p->pack_local || p->pack_keep)
2180                        continue;
2181                if (open_pack_index(p))
2182                        die("cannot open pack index");
2183
2184                ALLOC_GROW(in_pack.array,
2185                           in_pack.nr + p->num_objects,
2186                           in_pack.alloc);
2187
2188                for (i = 0; i < p->num_objects; i++) {
2189                        sha1 = nth_packed_object_sha1(p, i);
2190                        o = lookup_unknown_object(sha1);
2191                        if (!(o->flags & OBJECT_ADDED))
2192                                mark_in_pack_object(o, p, &in_pack);
2193                        o->flags |= OBJECT_ADDED;
2194                }
2195        }
2196
2197        if (in_pack.nr) {
2198                qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
2199                      ofscmp);
2200                for (i = 0; i < in_pack.nr; i++) {
2201                        struct object *o = in_pack.array[i].object;
2202                        add_object_entry(o->sha1, o->type, "", 0);
2203                }
2204        }
2205        free(in_pack.array);
2206}
2207
2208static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
2209{
2210        static struct packed_git *last_found = (void *)1;
2211        struct packed_git *p;
2212
2213        p = (last_found != (void *)1) ? last_found : packed_git;
2214
2215        while (p) {
2216                if ((!p->pack_local || p->pack_keep) &&
2217                        find_pack_entry_one(sha1, p)) {
2218                        last_found = p;
2219                        return 1;
2220                }
2221                if (p == last_found)
2222                        p = packed_git;
2223                else
2224                        p = p->next;
2225                if (p == last_found)
2226                        p = p->next;
2227        }
2228        return 0;
2229}
2230
2231static void loosen_unused_packed_objects(struct rev_info *revs)
2232{
2233        struct packed_git *p;
2234        uint32_t i;
2235        const unsigned char *sha1;
2236
2237        for (p = packed_git; p; p = p->next) {
2238                if (!p->pack_local || p->pack_keep)
2239                        continue;
2240
2241                if (unpack_unreachable_expiration &&
2242                    p->mtime < unpack_unreachable_expiration)
2243                        continue;
2244
2245                if (open_pack_index(p))
2246                        die("cannot open pack index");
2247
2248                for (i = 0; i < p->num_objects; i++) {
2249                        sha1 = nth_packed_object_sha1(p, i);
2250                        if (!packlist_find(&to_pack, sha1, NULL) &&
2251                                !has_sha1_pack_kept_or_nonlocal(sha1))
2252                                if (force_object_loose(sha1, p->mtime))
2253                                        die("unable to force loose object");
2254                }
2255        }
2256}
2257
2258static void get_object_list(int ac, const char **av)
2259{
2260        struct rev_info revs;
2261        char line[1000];
2262        int flags = 0;
2263
2264        init_revisions(&revs, NULL);
2265        save_commit_buffer = 0;
2266        setup_revisions(ac, av, &revs, NULL);
2267
2268        while (fgets(line, sizeof(line), stdin) != NULL) {
2269                int len = strlen(line);
2270                if (len && line[len - 1] == '\n')
2271                        line[--len] = 0;
2272                if (!len)
2273                        break;
2274                if (*line == '-') {
2275                        if (!strcmp(line, "--not")) {
2276                                flags ^= UNINTERESTING;
2277                                continue;
2278                        }
2279                        die("not a rev '%s'", line);
2280                }
2281                if (handle_revision_arg(line, &revs, flags, REVARG_CANNOT_BE_FILENAME))
2282                        die("bad revision '%s'", line);
2283        }
2284
2285        if (prepare_revision_walk(&revs))
2286                die("revision walk setup failed");
2287        mark_edges_uninteresting(&revs, show_edge);
2288        traverse_commit_list(&revs, show_commit, show_object, NULL);
2289
2290        if (keep_unreachable)
2291                add_objects_in_unpacked_packs(&revs);
2292        if (unpack_unreachable)
2293                loosen_unused_packed_objects(&revs);
2294}
2295
2296static int option_parse_index_version(const struct option *opt,
2297                                      const char *arg, int unset)
2298{
2299        char *c;
2300        const char *val = arg;
2301        pack_idx_opts.version = strtoul(val, &c, 10);
2302        if (pack_idx_opts.version > 2)
2303                die(_("unsupported index version %s"), val);
2304        if (*c == ',' && c[1])
2305                pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2306        if (*c || pack_idx_opts.off32_limit & 0x80000000)
2307                die(_("bad index version '%s'"), val);
2308        return 0;
2309}
2310
2311static int option_parse_unpack_unreachable(const struct option *opt,
2312                                           const char *arg, int unset)
2313{
2314        if (unset) {
2315                unpack_unreachable = 0;
2316                unpack_unreachable_expiration = 0;
2317        }
2318        else {
2319                unpack_unreachable = 1;
2320                if (arg)
2321                        unpack_unreachable_expiration = approxidate(arg);
2322        }
2323        return 0;
2324}
2325
2326static int option_parse_ulong(const struct option *opt,
2327                              const char *arg, int unset)
2328{
2329        if (unset)
2330                die(_("option %s does not accept negative form"),
2331                    opt->long_name);
2332
2333        if (!git_parse_ulong(arg, opt->value))
2334                die(_("unable to parse value '%s' for option %s"),
2335                    arg, opt->long_name);
2336        return 0;
2337}
2338
2339#define OPT_ULONG(s, l, v, h) \
2340        { OPTION_CALLBACK, (s), (l), (v), "n", (h),     \
2341          PARSE_OPT_NONEG, option_parse_ulong }
2342
2343int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2344{
2345        int use_internal_rev_list = 0;
2346        int thin = 0;
2347        int all_progress_implied = 0;
2348        const char *rp_av[6];
2349        int rp_ac = 0;
2350        int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
2351        struct option pack_objects_options[] = {
2352                OPT_SET_INT('q', "quiet", &progress,
2353                            N_("do not show progress meter"), 0),
2354                OPT_SET_INT(0, "progress", &progress,
2355                            N_("show progress meter"), 1),
2356                OPT_SET_INT(0, "all-progress", &progress,
2357                            N_("show progress meter during object writing phase"), 2),
2358                OPT_BOOL(0, "all-progress-implied",
2359                         &all_progress_implied,
2360                         N_("similar to --all-progress when progress meter is shown")),
2361                { OPTION_CALLBACK, 0, "index-version", NULL, N_("version[,offset]"),
2362                  N_("write the pack index file in the specified idx format version"),
2363                  0, option_parse_index_version },
2364                OPT_ULONG(0, "max-pack-size", &pack_size_limit,
2365                          N_("maximum size of each output pack file")),
2366                OPT_BOOL(0, "local", &local,
2367                         N_("ignore borrowed objects from alternate object store")),
2368                OPT_BOOL(0, "incremental", &incremental,
2369                         N_("ignore packed objects")),
2370                OPT_INTEGER(0, "window", &window,
2371                            N_("limit pack window by objects")),
2372                OPT_ULONG(0, "window-memory", &window_memory_limit,
2373                          N_("limit pack window by memory in addition to object limit")),
2374                OPT_INTEGER(0, "depth", &depth,
2375                            N_("maximum length of delta chain allowed in the resulting pack")),
2376                OPT_BOOL(0, "reuse-delta", &reuse_delta,
2377                         N_("reuse existing deltas")),
2378                OPT_BOOL(0, "reuse-object", &reuse_object,
2379                         N_("reuse existing objects")),
2380                OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
2381                         N_("use OFS_DELTA objects")),
2382                OPT_INTEGER(0, "threads", &delta_search_threads,
2383                            N_("use threads when searching for best delta matches")),
2384                OPT_BOOL(0, "non-empty", &non_empty,
2385                         N_("do not create an empty pack output")),
2386                OPT_BOOL(0, "revs", &use_internal_rev_list,
2387                         N_("read revision arguments from standard input")),
2388                { OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
2389                  N_("limit the objects to those that are not yet packed"),
2390                  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2391                { OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
2392                  N_("include objects reachable from any reference"),
2393                  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2394                { OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
2395                  N_("include objects referred by reflog entries"),
2396                  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2397                OPT_BOOL(0, "stdout", &pack_to_stdout,
2398                         N_("output pack to stdout")),
2399                OPT_BOOL(0, "include-tag", &include_tag,
2400                         N_("include tag objects that refer to objects to be packed")),
2401                OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
2402                         N_("keep unreachable objects")),
2403                { OPTION_CALLBACK, 0, "unpack-unreachable", NULL, N_("time"),
2404                  N_("unpack unreachable objects newer than <time>"),
2405                  PARSE_OPT_OPTARG, option_parse_unpack_unreachable },
2406                OPT_BOOL(0, "thin", &thin,
2407                         N_("create thin packs")),
2408                OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
2409                         N_("ignore packs that have companion .keep file")),
2410                OPT_INTEGER(0, "compression", &pack_compression_level,
2411                            N_("pack compression level")),
2412                OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
2413                            N_("do not hide commits by grafts"), 0),
2414                OPT_END(),
2415        };
2416
2417        read_replace_refs = 0;
2418
2419        reset_pack_idx_option(&pack_idx_opts);
2420        git_config(git_pack_config, NULL);
2421        if (!pack_compression_seen && core_compression_seen)
2422                pack_compression_level = core_compression_level;
2423
2424        progress = isatty(2);
2425        argc = parse_options(argc, argv, prefix, pack_objects_options,
2426                             pack_usage, 0);
2427
2428        if (argc) {
2429                base_name = argv[0];
2430                argc--;
2431        }
2432        if (pack_to_stdout != !base_name || argc)
2433                usage_with_options(pack_usage, pack_objects_options);
2434
2435        rp_av[rp_ac++] = "pack-objects";
2436        if (thin) {
2437                use_internal_rev_list = 1;
2438                rp_av[rp_ac++] = "--objects-edge";
2439        } else
2440                rp_av[rp_ac++] = "--objects";
2441
2442        if (rev_list_all) {
2443                use_internal_rev_list = 1;
2444                rp_av[rp_ac++] = "--all";
2445        }
2446        if (rev_list_reflog) {
2447                use_internal_rev_list = 1;
2448                rp_av[rp_ac++] = "--reflog";
2449        }
2450        if (rev_list_unpacked) {
2451                use_internal_rev_list = 1;
2452                rp_av[rp_ac++] = "--unpacked";
2453        }
2454
2455        if (!reuse_object)
2456                reuse_delta = 0;
2457        if (pack_compression_level == -1)
2458                pack_compression_level = Z_DEFAULT_COMPRESSION;
2459        else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
2460                die("bad pack compression level %d", pack_compression_level);
2461#ifdef NO_PTHREADS
2462        if (delta_search_threads != 1)
2463                warning("no threads support, ignoring --threads");
2464#endif
2465        if (!pack_to_stdout && !pack_size_limit)
2466                pack_size_limit = pack_size_limit_cfg;
2467        if (pack_to_stdout && pack_size_limit)
2468                die("--max-pack-size cannot be used to build a pack for transfer.");
2469        if (pack_size_limit && pack_size_limit < 1024*1024) {
2470                warning("minimum pack size limit is 1 MiB");
2471                pack_size_limit = 1024*1024;
2472        }
2473
2474        if (!pack_to_stdout && thin)
2475                die("--thin cannot be used to build an indexable pack.");
2476
2477        if (keep_unreachable && unpack_unreachable)
2478                die("--keep-unreachable and --unpack-unreachable are incompatible.");
2479
2480        if (progress && all_progress_implied)
2481                progress = 2;
2482
2483        prepare_packed_git();
2484
2485        if (progress)
2486                progress_state = start_progress("Counting objects", 0);
2487        if (!use_internal_rev_list)
2488                read_object_list_from_stdin();
2489        else {
2490                rp_av[rp_ac] = NULL;
2491                get_object_list(rp_ac, rp_av);
2492        }
2493        cleanup_preferred_base();
2494        if (include_tag && nr_result)
2495                for_each_ref(add_ref_tag, NULL);
2496        stop_progress(&progress_state);
2497
2498        if (non_empty && !nr_result)
2499                return 0;
2500        if (nr_result)
2501                prepare_pack(window, depth);
2502        write_pack_file();
2503        if (progress)
2504                fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
2505                        " reused %"PRIu32" (delta %"PRIu32")\n",
2506                        written, written_delta, reused, reused_delta);
2507        return 0;
2508}