builtin / pack-objects.con commit Merge branch 'jm/maint-strncpy-diff-no-index' into maint (a16ae14)
   1#include "builtin.h"
   2#include "cache.h"
   3#include "attr.h"
   4#include "object.h"
   5#include "blob.h"
   6#include "commit.h"
   7#include "tag.h"
   8#include "tree.h"
   9#include "delta.h"
  10#include "pack.h"
  11#include "pack-revindex.h"
  12#include "csum-file.h"
  13#include "tree-walk.h"
  14#include "diff.h"
  15#include "revision.h"
  16#include "list-objects.h"
  17#include "progress.h"
  18#include "refs.h"
  19#include "thread-utils.h"
  20
  21static const char *pack_usage[] = {
  22        "git pack-objects --stdout [options...] [< ref-list | < object-list]",
  23        "git pack-objects [options...] base-name [< ref-list | < object-list]",
  24        NULL
  25};
  26
  27struct object_entry {
  28        struct pack_idx_entry idx;
  29        unsigned long size;     /* uncompressed size */
  30        struct packed_git *in_pack;     /* already in pack */
  31        off_t in_pack_offset;
  32        struct object_entry *delta;     /* delta base object */
  33        struct object_entry *delta_child; /* deltified objects who bases me */
  34        struct object_entry *delta_sibling; /* other deltified objects who
  35                                             * uses the same base as me
  36                                             */
  37        void *delta_data;       /* cached delta (uncompressed) */
  38        unsigned long delta_size;       /* delta data size (uncompressed) */
  39        unsigned long z_delta_size;     /* delta data size (compressed) */
  40        unsigned int hash;      /* name hint hash */
  41        enum object_type type;
  42        enum object_type in_pack_type;  /* could be delta */
  43        unsigned char in_pack_header_size;
  44        unsigned char preferred_base; /* we do not pack this, but is available
  45                                       * to be used as the base object to delta
  46                                       * objects against.
  47                                       */
  48        unsigned char no_try_delta;
  49        unsigned char tagged; /* near the very tip of refs */
  50        unsigned char filled; /* assigned write-order */
  51};
  52
  53/*
  54 * Objects we are going to pack are collected in objects array (dynamically
  55 * expanded).  nr_objects & nr_alloc controls this array.  They are stored
  56 * in the order we see -- typically rev-list --objects order that gives us
  57 * nice "minimum seek" order.
  58 */
  59static struct object_entry *objects;
  60static struct pack_idx_entry **written_list;
  61static uint32_t nr_objects, nr_alloc, nr_result, nr_written;
  62
  63static int non_empty;
  64static int reuse_delta = 1, reuse_object = 1;
  65static int keep_unreachable, unpack_unreachable, include_tag;
  66static int local;
  67static int incremental;
  68static int ignore_packed_keep;
  69static int allow_ofs_delta;
  70static struct pack_idx_option pack_idx_opts;
  71static const char *base_name;
  72static int progress = 1;
  73static int window = 10;
  74static unsigned long pack_size_limit;
  75static int depth = 50;
  76static int delta_search_threads;
  77static int pack_to_stdout;
  78static int num_preferred_base;
  79static struct progress *progress_state;
  80static int pack_compression_level = Z_DEFAULT_COMPRESSION;
  81static int pack_compression_seen;
  82
  83static unsigned long delta_cache_size = 0;
  84static unsigned long max_delta_cache_size = 256 * 1024 * 1024;
  85static unsigned long cache_max_small_delta_size = 1000;
  86
  87static unsigned long window_memory_limit = 0;
  88
  89/*
  90 * The object names in objects array are hashed with this hashtable,
  91 * to help looking up the entry by object name.
  92 * This hashtable is built after all the objects are seen.
  93 */
  94static int *object_ix;
  95static int object_ix_hashsz;
  96static struct object_entry *locate_object_entry(const unsigned char *sha1);
  97
  98/*
  99 * stats
 100 */
 101static uint32_t written, written_delta;
 102static uint32_t reused, reused_delta;
 103
 104
 105static void *get_delta(struct object_entry *entry)
 106{
 107        unsigned long size, base_size, delta_size;
 108        void *buf, *base_buf, *delta_buf;
 109        enum object_type type;
 110
 111        buf = read_sha1_file(entry->idx.sha1, &type, &size);
 112        if (!buf)
 113                die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 114        base_buf = read_sha1_file(entry->delta->idx.sha1, &type, &base_size);
 115        if (!base_buf)
 116                die("unable to read %s", sha1_to_hex(entry->delta->idx.sha1));
 117        delta_buf = diff_delta(base_buf, base_size,
 118                               buf, size, &delta_size, 0);
 119        if (!delta_buf || delta_size != entry->delta_size)
 120                die("delta size changed");
 121        free(buf);
 122        free(base_buf);
 123        return delta_buf;
 124}
 125
 126static unsigned long do_compress(void **pptr, unsigned long size)
 127{
 128        git_zstream stream;
 129        void *in, *out;
 130        unsigned long maxsize;
 131
 132        memset(&stream, 0, sizeof(stream));
 133        git_deflate_init(&stream, pack_compression_level);
 134        maxsize = git_deflate_bound(&stream, size);
 135
 136        in = *pptr;
 137        out = xmalloc(maxsize);
 138        *pptr = out;
 139
 140        stream.next_in = in;
 141        stream.avail_in = size;
 142        stream.next_out = out;
 143        stream.avail_out = maxsize;
 144        while (git_deflate(&stream, Z_FINISH) == Z_OK)
 145                ; /* nothing */
 146        git_deflate_end(&stream);
 147
 148        free(in);
 149        return stream.total_out;
 150}
 151
 152/*
 153 * we are going to reuse the existing object data as is.  make
 154 * sure it is not corrupt.
 155 */
 156static int check_pack_inflate(struct packed_git *p,
 157                struct pack_window **w_curs,
 158                off_t offset,
 159                off_t len,
 160                unsigned long expect)
 161{
 162        git_zstream stream;
 163        unsigned char fakebuf[4096], *in;
 164        int st;
 165
 166        memset(&stream, 0, sizeof(stream));
 167        git_inflate_init(&stream);
 168        do {
 169                in = use_pack(p, w_curs, offset, &stream.avail_in);
 170                stream.next_in = in;
 171                stream.next_out = fakebuf;
 172                stream.avail_out = sizeof(fakebuf);
 173                st = git_inflate(&stream, Z_FINISH);
 174                offset += stream.next_in - in;
 175        } while (st == Z_OK || st == Z_BUF_ERROR);
 176        git_inflate_end(&stream);
 177        return (st == Z_STREAM_END &&
 178                stream.total_out == expect &&
 179                stream.total_in == len) ? 0 : -1;
 180}
 181
 182static void copy_pack_data(struct sha1file *f,
 183                struct packed_git *p,
 184                struct pack_window **w_curs,
 185                off_t offset,
 186                off_t len)
 187{
 188        unsigned char *in;
 189        unsigned long avail;
 190
 191        while (len) {
 192                in = use_pack(p, w_curs, offset, &avail);
 193                if (avail > len)
 194                        avail = (unsigned long)len;
 195                sha1write(f, in, avail);
 196                offset += avail;
 197                len -= avail;
 198        }
 199}
 200
 201/* Return 0 if we will bust the pack-size limit */
 202static unsigned long write_object(struct sha1file *f,
 203                                  struct object_entry *entry,
 204                                  off_t write_offset)
 205{
 206        unsigned long size, limit, datalen;
 207        void *buf;
 208        unsigned char header[10], dheader[10];
 209        unsigned hdrlen;
 210        enum object_type type;
 211        int usable_delta, to_reuse;
 212
 213        if (!pack_to_stdout)
 214                crc32_begin(f);
 215
 216        type = entry->type;
 217
 218        /* apply size limit if limited packsize and not first object */
 219        if (!pack_size_limit || !nr_written)
 220                limit = 0;
 221        else if (pack_size_limit <= write_offset)
 222                /*
 223                 * the earlier object did not fit the limit; avoid
 224                 * mistaking this with unlimited (i.e. limit = 0).
 225                 */
 226                limit = 1;
 227        else
 228                limit = pack_size_limit - write_offset;
 229
 230        if (!entry->delta)
 231                usable_delta = 0;       /* no delta */
 232        else if (!pack_size_limit)
 233               usable_delta = 1;        /* unlimited packfile */
 234        else if (entry->delta->idx.offset == (off_t)-1)
 235                usable_delta = 0;       /* base was written to another pack */
 236        else if (entry->delta->idx.offset)
 237                usable_delta = 1;       /* base already exists in this pack */
 238        else
 239                usable_delta = 0;       /* base could end up in another pack */
 240
 241        if (!reuse_object)
 242                to_reuse = 0;   /* explicit */
 243        else if (!entry->in_pack)
 244                to_reuse = 0;   /* can't reuse what we don't have */
 245        else if (type == OBJ_REF_DELTA || type == OBJ_OFS_DELTA)
 246                                /* check_object() decided it for us ... */
 247                to_reuse = usable_delta;
 248                                /* ... but pack split may override that */
 249        else if (type != entry->in_pack_type)
 250                to_reuse = 0;   /* pack has delta which is unusable */
 251        else if (entry->delta)
 252                to_reuse = 0;   /* we want to pack afresh */
 253        else
 254                to_reuse = 1;   /* we have it in-pack undeltified,
 255                                 * and we do not need to deltify it.
 256                                 */
 257
 258        if (!to_reuse) {
 259                no_reuse:
 260                if (!usable_delta) {
 261                        buf = read_sha1_file(entry->idx.sha1, &type, &size);
 262                        if (!buf)
 263                                die("unable to read %s", sha1_to_hex(entry->idx.sha1));
 264                        /*
 265                         * make sure no cached delta data remains from a
 266                         * previous attempt before a pack split occurred.
 267                         */
 268                        free(entry->delta_data);
 269                        entry->delta_data = NULL;
 270                        entry->z_delta_size = 0;
 271                } else if (entry->delta_data) {
 272                        size = entry->delta_size;
 273                        buf = entry->delta_data;
 274                        entry->delta_data = NULL;
 275                        type = (allow_ofs_delta && entry->delta->idx.offset) ?
 276                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 277                } else {
 278                        buf = get_delta(entry);
 279                        size = entry->delta_size;
 280                        type = (allow_ofs_delta && entry->delta->idx.offset) ?
 281                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 282                }
 283
 284                if (entry->z_delta_size)
 285                        datalen = entry->z_delta_size;
 286                else
 287                        datalen = do_compress(&buf, size);
 288
 289                /*
 290                 * The object header is a byte of 'type' followed by zero or
 291                 * more bytes of length.
 292                 */
 293                hdrlen = encode_in_pack_object_header(type, size, header);
 294
 295                if (type == OBJ_OFS_DELTA) {
 296                        /*
 297                         * Deltas with relative base contain an additional
 298                         * encoding of the relative offset for the delta
 299                         * base from this object's position in the pack.
 300                         */
 301                        off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 302                        unsigned pos = sizeof(dheader) - 1;
 303                        dheader[pos] = ofs & 127;
 304                        while (ofs >>= 7)
 305                                dheader[--pos] = 128 | (--ofs & 127);
 306                        if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 307                                free(buf);
 308                                return 0;
 309                        }
 310                        sha1write(f, header, hdrlen);
 311                        sha1write(f, dheader + pos, sizeof(dheader) - pos);
 312                        hdrlen += sizeof(dheader) - pos;
 313                } else if (type == OBJ_REF_DELTA) {
 314                        /*
 315                         * Deltas with a base reference contain
 316                         * an additional 20 bytes for the base sha1.
 317                         */
 318                        if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 319                                free(buf);
 320                                return 0;
 321                        }
 322                        sha1write(f, header, hdrlen);
 323                        sha1write(f, entry->delta->idx.sha1, 20);
 324                        hdrlen += 20;
 325                } else {
 326                        if (limit && hdrlen + datalen + 20 >= limit) {
 327                                free(buf);
 328                                return 0;
 329                        }
 330                        sha1write(f, header, hdrlen);
 331                }
 332                sha1write(f, buf, datalen);
 333                free(buf);
 334        }
 335        else {
 336                struct packed_git *p = entry->in_pack;
 337                struct pack_window *w_curs = NULL;
 338                struct revindex_entry *revidx;
 339                off_t offset;
 340
 341                if (entry->delta)
 342                        type = (allow_ofs_delta && entry->delta->idx.offset) ?
 343                                OBJ_OFS_DELTA : OBJ_REF_DELTA;
 344                hdrlen = encode_in_pack_object_header(type, entry->size, header);
 345
 346                offset = entry->in_pack_offset;
 347                revidx = find_pack_revindex(p, offset);
 348                datalen = revidx[1].offset - offset;
 349                if (!pack_to_stdout && p->index_version > 1 &&
 350                    check_pack_crc(p, &w_curs, offset, datalen, revidx->nr)) {
 351                        error("bad packed object CRC for %s", sha1_to_hex(entry->idx.sha1));
 352                        unuse_pack(&w_curs);
 353                        goto no_reuse;
 354                }
 355
 356                offset += entry->in_pack_header_size;
 357                datalen -= entry->in_pack_header_size;
 358                if (!pack_to_stdout && p->index_version == 1 &&
 359                    check_pack_inflate(p, &w_curs, offset, datalen, entry->size)) {
 360                        error("corrupt packed object for %s", sha1_to_hex(entry->idx.sha1));
 361                        unuse_pack(&w_curs);
 362                        goto no_reuse;
 363                }
 364
 365                if (type == OBJ_OFS_DELTA) {
 366                        off_t ofs = entry->idx.offset - entry->delta->idx.offset;
 367                        unsigned pos = sizeof(dheader) - 1;
 368                        dheader[pos] = ofs & 127;
 369                        while (ofs >>= 7)
 370                                dheader[--pos] = 128 | (--ofs & 127);
 371                        if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
 372                                unuse_pack(&w_curs);
 373                                return 0;
 374                        }
 375                        sha1write(f, header, hdrlen);
 376                        sha1write(f, dheader + pos, sizeof(dheader) - pos);
 377                        hdrlen += sizeof(dheader) - pos;
 378                        reused_delta++;
 379                } else if (type == OBJ_REF_DELTA) {
 380                        if (limit && hdrlen + 20 + datalen + 20 >= limit) {
 381                                unuse_pack(&w_curs);
 382                                return 0;
 383                        }
 384                        sha1write(f, header, hdrlen);
 385                        sha1write(f, entry->delta->idx.sha1, 20);
 386                        hdrlen += 20;
 387                        reused_delta++;
 388                } else {
 389                        if (limit && hdrlen + datalen + 20 >= limit) {
 390                                unuse_pack(&w_curs);
 391                                return 0;
 392                        }
 393                        sha1write(f, header, hdrlen);
 394                }
 395                copy_pack_data(f, p, &w_curs, offset, datalen);
 396                unuse_pack(&w_curs);
 397                reused++;
 398        }
 399        if (usable_delta)
 400                written_delta++;
 401        written++;
 402        if (!pack_to_stdout)
 403                entry->idx.crc32 = crc32_end(f);
 404        return hdrlen + datalen;
 405}
 406
 407enum write_one_status {
 408        WRITE_ONE_SKIP = -1, /* already written */
 409        WRITE_ONE_BREAK = 0, /* writing this will bust the limit; not written */
 410        WRITE_ONE_WRITTEN = 1, /* normal */
 411        WRITE_ONE_RECURSIVE = 2 /* already scheduled to be written */
 412};
 413
 414static enum write_one_status write_one(struct sha1file *f,
 415                                       struct object_entry *e,
 416                                       off_t *offset)
 417{
 418        unsigned long size;
 419        int recursing;
 420
 421        /*
 422         * we set offset to 1 (which is an impossible value) to mark
 423         * the fact that this object is involved in "write its base
 424         * first before writing a deltified object" recursion.
 425         */
 426        recursing = (e->idx.offset == 1);
 427        if (recursing) {
 428                warning("recursive delta detected for object %s",
 429                        sha1_to_hex(e->idx.sha1));
 430                return WRITE_ONE_RECURSIVE;
 431        } else if (e->idx.offset || e->preferred_base) {
 432                /* offset is non zero if object is written already. */
 433                return WRITE_ONE_SKIP;
 434        }
 435
 436        /* if we are deltified, write out base object first. */
 437        if (e->delta) {
 438                e->idx.offset = 1; /* now recurse */
 439                switch (write_one(f, e->delta, offset)) {
 440                case WRITE_ONE_RECURSIVE:
 441                        /* we cannot depend on this one */
 442                        e->delta = NULL;
 443                        break;
 444                default:
 445                        break;
 446                case WRITE_ONE_BREAK:
 447                        e->idx.offset = recursing;
 448                        return WRITE_ONE_BREAK;
 449                }
 450        }
 451
 452        e->idx.offset = *offset;
 453        size = write_object(f, e, *offset);
 454        if (!size) {
 455                e->idx.offset = recursing;
 456                return WRITE_ONE_BREAK;
 457        }
 458        written_list[nr_written++] = &e->idx;
 459
 460        /* make sure off_t is sufficiently large not to wrap */
 461        if (signed_add_overflows(*offset, size))
 462                die("pack too large for current definition of off_t");
 463        *offset += size;
 464        return WRITE_ONE_WRITTEN;
 465}
 466
 467static int mark_tagged(const char *path, const unsigned char *sha1, int flag,
 468                       void *cb_data)
 469{
 470        unsigned char peeled[20];
 471        struct object_entry *entry = locate_object_entry(sha1);
 472
 473        if (entry)
 474                entry->tagged = 1;
 475        if (!peel_ref(path, peeled)) {
 476                entry = locate_object_entry(peeled);
 477                if (entry)
 478                        entry->tagged = 1;
 479        }
 480        return 0;
 481}
 482
 483static inline void add_to_write_order(struct object_entry **wo,
 484                               unsigned int *endp,
 485                               struct object_entry *e)
 486{
 487        if (e->filled)
 488                return;
 489        wo[(*endp)++] = e;
 490        e->filled = 1;
 491}
 492
 493static void add_descendants_to_write_order(struct object_entry **wo,
 494                                           unsigned int *endp,
 495                                           struct object_entry *e)
 496{
 497        int add_to_order = 1;
 498        while (e) {
 499                if (add_to_order) {
 500                        struct object_entry *s;
 501                        /* add this node... */
 502                        add_to_write_order(wo, endp, e);
 503                        /* all its siblings... */
 504                        for (s = e->delta_sibling; s; s = s->delta_sibling) {
 505                                add_to_write_order(wo, endp, s);
 506                        }
 507                }
 508                /* drop down a level to add left subtree nodes if possible */
 509                if (e->delta_child) {
 510                        add_to_order = 1;
 511                        e = e->delta_child;
 512                } else {
 513                        add_to_order = 0;
 514                        /* our sibling might have some children, it is next */
 515                        if (e->delta_sibling) {
 516                                e = e->delta_sibling;
 517                                continue;
 518                        }
 519                        /* go back to our parent node */
 520                        e = e->delta;
 521                        while (e && !e->delta_sibling) {
 522                                /* we're on the right side of a subtree, keep
 523                                 * going up until we can go right again */
 524                                e = e->delta;
 525                        }
 526                        if (!e) {
 527                                /* done- we hit our original root node */
 528                                return;
 529                        }
 530                        /* pass it off to sibling at this level */
 531                        e = e->delta_sibling;
 532                }
 533        };
 534}
 535
 536static void add_family_to_write_order(struct object_entry **wo,
 537                                      unsigned int *endp,
 538                                      struct object_entry *e)
 539{
 540        struct object_entry *root;
 541
 542        for (root = e; root->delta; root = root->delta)
 543                ; /* nothing */
 544        add_descendants_to_write_order(wo, endp, root);
 545}
 546
 547static struct object_entry **compute_write_order(void)
 548{
 549        unsigned int i, wo_end, last_untagged;
 550
 551        struct object_entry **wo = xmalloc(nr_objects * sizeof(*wo));
 552
 553        for (i = 0; i < nr_objects; i++) {
 554                objects[i].tagged = 0;
 555                objects[i].filled = 0;
 556                objects[i].delta_child = NULL;
 557                objects[i].delta_sibling = NULL;
 558        }
 559
 560        /*
 561         * Fully connect delta_child/delta_sibling network.
 562         * Make sure delta_sibling is sorted in the original
 563         * recency order.
 564         */
 565        for (i = nr_objects; i > 0;) {
 566                struct object_entry *e = &objects[--i];
 567                if (!e->delta)
 568                        continue;
 569                /* Mark me as the first child */
 570                e->delta_sibling = e->delta->delta_child;
 571                e->delta->delta_child = e;
 572        }
 573
 574        /*
 575         * Mark objects that are at the tip of tags.
 576         */
 577        for_each_tag_ref(mark_tagged, NULL);
 578
 579        /*
 580         * Give the objects in the original recency order until
 581         * we see a tagged tip.
 582         */
 583        for (i = wo_end = 0; i < nr_objects; i++) {
 584                if (objects[i].tagged)
 585                        break;
 586                add_to_write_order(wo, &wo_end, &objects[i]);
 587        }
 588        last_untagged = i;
 589
 590        /*
 591         * Then fill all the tagged tips.
 592         */
 593        for (; i < nr_objects; i++) {
 594                if (objects[i].tagged)
 595                        add_to_write_order(wo, &wo_end, &objects[i]);
 596        }
 597
 598        /*
 599         * And then all remaining commits and tags.
 600         */
 601        for (i = last_untagged; i < nr_objects; i++) {
 602                if (objects[i].type != OBJ_COMMIT &&
 603                    objects[i].type != OBJ_TAG)
 604                        continue;
 605                add_to_write_order(wo, &wo_end, &objects[i]);
 606        }
 607
 608        /*
 609         * And then all the trees.
 610         */
 611        for (i = last_untagged; i < nr_objects; i++) {
 612                if (objects[i].type != OBJ_TREE)
 613                        continue;
 614                add_to_write_order(wo, &wo_end, &objects[i]);
 615        }
 616
 617        /*
 618         * Finally all the rest in really tight order
 619         */
 620        for (i = last_untagged; i < nr_objects; i++) {
 621                if (!objects[i].filled)
 622                        add_family_to_write_order(wo, &wo_end, &objects[i]);
 623        }
 624
 625        if (wo_end != nr_objects)
 626                die("ordered %u objects, expected %"PRIu32, wo_end, nr_objects);
 627
 628        return wo;
 629}
 630
 631static void write_pack_file(void)
 632{
 633        uint32_t i = 0, j;
 634        struct sha1file *f;
 635        off_t offset;
 636        uint32_t nr_remaining = nr_result;
 637        time_t last_mtime = 0;
 638        struct object_entry **write_order;
 639
 640        if (progress > pack_to_stdout)
 641                progress_state = start_progress("Writing objects", nr_result);
 642        written_list = xmalloc(nr_objects * sizeof(*written_list));
 643        write_order = compute_write_order();
 644
 645        do {
 646                unsigned char sha1[20];
 647                char *pack_tmp_name = NULL;
 648
 649                if (pack_to_stdout)
 650                        f = sha1fd_throughput(1, "<stdout>", progress_state);
 651                else
 652                        f = create_tmp_packfile(&pack_tmp_name);
 653
 654                offset = write_pack_header(f, nr_remaining);
 655                if (!offset)
 656                        die_errno("unable to write pack header");
 657                nr_written = 0;
 658                for (; i < nr_objects; i++) {
 659                        struct object_entry *e = write_order[i];
 660                        if (write_one(f, e, &offset) == WRITE_ONE_BREAK)
 661                                break;
 662                        display_progress(progress_state, written);
 663                }
 664
 665                /*
 666                 * Did we write the wrong # entries in the header?
 667                 * If so, rewrite it like in fast-import
 668                 */
 669                if (pack_to_stdout) {
 670                        sha1close(f, sha1, CSUM_CLOSE);
 671                } else if (nr_written == nr_remaining) {
 672                        sha1close(f, sha1, CSUM_FSYNC);
 673                } else {
 674                        int fd = sha1close(f, sha1, 0);
 675                        fixup_pack_header_footer(fd, sha1, pack_tmp_name,
 676                                                 nr_written, sha1, offset);
 677                        close(fd);
 678                }
 679
 680                if (!pack_to_stdout) {
 681                        struct stat st;
 682                        char tmpname[PATH_MAX];
 683
 684                        /*
 685                         * Packs are runtime accessed in their mtime
 686                         * order since newer packs are more likely to contain
 687                         * younger objects.  So if we are creating multiple
 688                         * packs then we should modify the mtime of later ones
 689                         * to preserve this property.
 690                         */
 691                        if (stat(pack_tmp_name, &st) < 0) {
 692                                warning("failed to stat %s: %s",
 693                                        pack_tmp_name, strerror(errno));
 694                        } else if (!last_mtime) {
 695                                last_mtime = st.st_mtime;
 696                        } else {
 697                                struct utimbuf utb;
 698                                utb.actime = st.st_atime;
 699                                utb.modtime = --last_mtime;
 700                                if (utime(pack_tmp_name, &utb) < 0)
 701                                        warning("failed utime() on %s: %s",
 702                                                tmpname, strerror(errno));
 703                        }
 704
 705                        /* Enough space for "-<sha-1>.pack"? */
 706                        if (sizeof(tmpname) <= strlen(base_name) + 50)
 707                                die("pack base name '%s' too long", base_name);
 708                        snprintf(tmpname, sizeof(tmpname), "%s-", base_name);
 709                        finish_tmp_packfile(tmpname, pack_tmp_name,
 710                                            written_list, nr_written,
 711                                            &pack_idx_opts, sha1);
 712                        free(pack_tmp_name);
 713                        puts(sha1_to_hex(sha1));
 714                }
 715
 716                /* mark written objects as written to previous pack */
 717                for (j = 0; j < nr_written; j++) {
 718                        written_list[j]->offset = (off_t)-1;
 719                }
 720                nr_remaining -= nr_written;
 721        } while (nr_remaining && i < nr_objects);
 722
 723        free(written_list);
 724        free(write_order);
 725        stop_progress(&progress_state);
 726        if (written != nr_result)
 727                die("wrote %"PRIu32" objects while expecting %"PRIu32,
 728                        written, nr_result);
 729}
 730
 731static int locate_object_entry_hash(const unsigned char *sha1)
 732{
 733        int i;
 734        unsigned int ui;
 735        memcpy(&ui, sha1, sizeof(unsigned int));
 736        i = ui % object_ix_hashsz;
 737        while (0 < object_ix[i]) {
 738                if (!hashcmp(sha1, objects[object_ix[i] - 1].idx.sha1))
 739                        return i;
 740                if (++i == object_ix_hashsz)
 741                        i = 0;
 742        }
 743        return -1 - i;
 744}
 745
 746static struct object_entry *locate_object_entry(const unsigned char *sha1)
 747{
 748        int i;
 749
 750        if (!object_ix_hashsz)
 751                return NULL;
 752
 753        i = locate_object_entry_hash(sha1);
 754        if (0 <= i)
 755                return &objects[object_ix[i]-1];
 756        return NULL;
 757}
 758
 759static void rehash_objects(void)
 760{
 761        uint32_t i;
 762        struct object_entry *oe;
 763
 764        object_ix_hashsz = nr_objects * 3;
 765        if (object_ix_hashsz < 1024)
 766                object_ix_hashsz = 1024;
 767        object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz);
 768        memset(object_ix, 0, sizeof(int) * object_ix_hashsz);
 769        for (i = 0, oe = objects; i < nr_objects; i++, oe++) {
 770                int ix = locate_object_entry_hash(oe->idx.sha1);
 771                if (0 <= ix)
 772                        continue;
 773                ix = -1 - ix;
 774                object_ix[ix] = i + 1;
 775        }
 776}
 777
 778static unsigned name_hash(const char *name)
 779{
 780        unsigned c, hash = 0;
 781
 782        if (!name)
 783                return 0;
 784
 785        /*
 786         * This effectively just creates a sortable number from the
 787         * last sixteen non-whitespace characters. Last characters
 788         * count "most", so things that end in ".c" sort together.
 789         */
 790        while ((c = *name++) != 0) {
 791                if (isspace(c))
 792                        continue;
 793                hash = (hash >> 2) + (c << 24);
 794        }
 795        return hash;
 796}
 797
 798static void setup_delta_attr_check(struct git_attr_check *check)
 799{
 800        static struct git_attr *attr_delta;
 801
 802        if (!attr_delta)
 803                attr_delta = git_attr("delta");
 804
 805        check[0].attr = attr_delta;
 806}
 807
 808static int no_try_delta(const char *path)
 809{
 810        struct git_attr_check check[1];
 811
 812        setup_delta_attr_check(check);
 813        if (git_check_attr(path, ARRAY_SIZE(check), check))
 814                return 0;
 815        if (ATTR_FALSE(check->value))
 816                return 1;
 817        return 0;
 818}
 819
 820static int add_object_entry(const unsigned char *sha1, enum object_type type,
 821                            const char *name, int exclude)
 822{
 823        struct object_entry *entry;
 824        struct packed_git *p, *found_pack = NULL;
 825        off_t found_offset = 0;
 826        int ix;
 827        unsigned hash = name_hash(name);
 828
 829        ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
 830        if (ix >= 0) {
 831                if (exclude) {
 832                        entry = objects + object_ix[ix] - 1;
 833                        if (!entry->preferred_base)
 834                                nr_result--;
 835                        entry->preferred_base = 1;
 836                }
 837                return 0;
 838        }
 839
 840        if (!exclude && local && has_loose_object_nonlocal(sha1))
 841                return 0;
 842
 843        for (p = packed_git; p; p = p->next) {
 844                off_t offset = find_pack_entry_one(sha1, p);
 845                if (offset) {
 846                        if (!found_pack) {
 847                                if (!is_pack_valid(p)) {
 848                                        warning("packfile %s cannot be accessed", p->pack_name);
 849                                        continue;
 850                                }
 851                                found_offset = offset;
 852                                found_pack = p;
 853                        }
 854                        if (exclude)
 855                                break;
 856                        if (incremental)
 857                                return 0;
 858                        if (local && !p->pack_local)
 859                                return 0;
 860                        if (ignore_packed_keep && p->pack_local && p->pack_keep)
 861                                return 0;
 862                }
 863        }
 864
 865        if (nr_objects >= nr_alloc) {
 866                nr_alloc = (nr_alloc  + 1024) * 3 / 2;
 867                objects = xrealloc(objects, nr_alloc * sizeof(*entry));
 868        }
 869
 870        entry = objects + nr_objects++;
 871        memset(entry, 0, sizeof(*entry));
 872        hashcpy(entry->idx.sha1, sha1);
 873        entry->hash = hash;
 874        if (type)
 875                entry->type = type;
 876        if (exclude)
 877                entry->preferred_base = 1;
 878        else
 879                nr_result++;
 880        if (found_pack) {
 881                entry->in_pack = found_pack;
 882                entry->in_pack_offset = found_offset;
 883        }
 884
 885        if (object_ix_hashsz * 3 <= nr_objects * 4)
 886                rehash_objects();
 887        else
 888                object_ix[-1 - ix] = nr_objects;
 889
 890        display_progress(progress_state, nr_objects);
 891
 892        if (name && no_try_delta(name))
 893                entry->no_try_delta = 1;
 894
 895        return 1;
 896}
 897
 898struct pbase_tree_cache {
 899        unsigned char sha1[20];
 900        int ref;
 901        int temporary;
 902        void *tree_data;
 903        unsigned long tree_size;
 904};
 905
 906static struct pbase_tree_cache *(pbase_tree_cache[256]);
 907static int pbase_tree_cache_ix(const unsigned char *sha1)
 908{
 909        return sha1[0] % ARRAY_SIZE(pbase_tree_cache);
 910}
 911static int pbase_tree_cache_ix_incr(int ix)
 912{
 913        return (ix+1) % ARRAY_SIZE(pbase_tree_cache);
 914}
 915
 916static struct pbase_tree {
 917        struct pbase_tree *next;
 918        /* This is a phony "cache" entry; we are not
 919         * going to evict it nor find it through _get()
 920         * mechanism -- this is for the toplevel node that
 921         * would almost always change with any commit.
 922         */
 923        struct pbase_tree_cache pcache;
 924} *pbase_tree;
 925
 926static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1)
 927{
 928        struct pbase_tree_cache *ent, *nent;
 929        void *data;
 930        unsigned long size;
 931        enum object_type type;
 932        int neigh;
 933        int my_ix = pbase_tree_cache_ix(sha1);
 934        int available_ix = -1;
 935
 936        /* pbase-tree-cache acts as a limited hashtable.
 937         * your object will be found at your index or within a few
 938         * slots after that slot if it is cached.
 939         */
 940        for (neigh = 0; neigh < 8; neigh++) {
 941                ent = pbase_tree_cache[my_ix];
 942                if (ent && !hashcmp(ent->sha1, sha1)) {
 943                        ent->ref++;
 944                        return ent;
 945                }
 946                else if (((available_ix < 0) && (!ent || !ent->ref)) ||
 947                         ((0 <= available_ix) &&
 948                          (!ent && pbase_tree_cache[available_ix])))
 949                        available_ix = my_ix;
 950                if (!ent)
 951                        break;
 952                my_ix = pbase_tree_cache_ix_incr(my_ix);
 953        }
 954
 955        /* Did not find one.  Either we got a bogus request or
 956         * we need to read and perhaps cache.
 957         */
 958        data = read_sha1_file(sha1, &type, &size);
 959        if (!data)
 960                return NULL;
 961        if (type != OBJ_TREE) {
 962                free(data);
 963                return NULL;
 964        }
 965
 966        /* We need to either cache or return a throwaway copy */
 967
 968        if (available_ix < 0)
 969                ent = NULL;
 970        else {
 971                ent = pbase_tree_cache[available_ix];
 972                my_ix = available_ix;
 973        }
 974
 975        if (!ent) {
 976                nent = xmalloc(sizeof(*nent));
 977                nent->temporary = (available_ix < 0);
 978        }
 979        else {
 980                /* evict and reuse */
 981                free(ent->tree_data);
 982                nent = ent;
 983        }
 984        hashcpy(nent->sha1, sha1);
 985        nent->tree_data = data;
 986        nent->tree_size = size;
 987        nent->ref = 1;
 988        if (!nent->temporary)
 989                pbase_tree_cache[my_ix] = nent;
 990        return nent;
 991}
 992
 993static void pbase_tree_put(struct pbase_tree_cache *cache)
 994{
 995        if (!cache->temporary) {
 996                cache->ref--;
 997                return;
 998        }
 999        free(cache->tree_data);
1000        free(cache);
1001}
1002
1003static int name_cmp_len(const char *name)
1004{
1005        int i;
1006        for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++)
1007                ;
1008        return i;
1009}
1010
1011static void add_pbase_object(struct tree_desc *tree,
1012                             const char *name,
1013                             int cmplen,
1014                             const char *fullname)
1015{
1016        struct name_entry entry;
1017        int cmp;
1018
1019        while (tree_entry(tree,&entry)) {
1020                if (S_ISGITLINK(entry.mode))
1021                        continue;
1022                cmp = tree_entry_len(&entry) != cmplen ? 1 :
1023                      memcmp(name, entry.path, cmplen);
1024                if (cmp > 0)
1025                        continue;
1026                if (cmp < 0)
1027                        return;
1028                if (name[cmplen] != '/') {
1029                        add_object_entry(entry.sha1,
1030                                         object_type(entry.mode),
1031                                         fullname, 1);
1032                        return;
1033                }
1034                if (S_ISDIR(entry.mode)) {
1035                        struct tree_desc sub;
1036                        struct pbase_tree_cache *tree;
1037                        const char *down = name+cmplen+1;
1038                        int downlen = name_cmp_len(down);
1039
1040                        tree = pbase_tree_get(entry.sha1);
1041                        if (!tree)
1042                                return;
1043                        init_tree_desc(&sub, tree->tree_data, tree->tree_size);
1044
1045                        add_pbase_object(&sub, down, downlen, fullname);
1046                        pbase_tree_put(tree);
1047                }
1048        }
1049}
1050
1051static unsigned *done_pbase_paths;
1052static int done_pbase_paths_num;
1053static int done_pbase_paths_alloc;
1054static int done_pbase_path_pos(unsigned hash)
1055{
1056        int lo = 0;
1057        int hi = done_pbase_paths_num;
1058        while (lo < hi) {
1059                int mi = (hi + lo) / 2;
1060                if (done_pbase_paths[mi] == hash)
1061                        return mi;
1062                if (done_pbase_paths[mi] < hash)
1063                        hi = mi;
1064                else
1065                        lo = mi + 1;
1066        }
1067        return -lo-1;
1068}
1069
1070static int check_pbase_path(unsigned hash)
1071{
1072        int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash);
1073        if (0 <= pos)
1074                return 1;
1075        pos = -pos - 1;
1076        if (done_pbase_paths_alloc <= done_pbase_paths_num) {
1077                done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc);
1078                done_pbase_paths = xrealloc(done_pbase_paths,
1079                                            done_pbase_paths_alloc *
1080                                            sizeof(unsigned));
1081        }
1082        done_pbase_paths_num++;
1083        if (pos < done_pbase_paths_num)
1084                memmove(done_pbase_paths + pos + 1,
1085                        done_pbase_paths + pos,
1086                        (done_pbase_paths_num - pos - 1) * sizeof(unsigned));
1087        done_pbase_paths[pos] = hash;
1088        return 0;
1089}
1090
1091static void add_preferred_base_object(const char *name)
1092{
1093        struct pbase_tree *it;
1094        int cmplen;
1095        unsigned hash = name_hash(name);
1096
1097        if (!num_preferred_base || check_pbase_path(hash))
1098                return;
1099
1100        cmplen = name_cmp_len(name);
1101        for (it = pbase_tree; it; it = it->next) {
1102                if (cmplen == 0) {
1103                        add_object_entry(it->pcache.sha1, OBJ_TREE, NULL, 1);
1104                }
1105                else {
1106                        struct tree_desc tree;
1107                        init_tree_desc(&tree, it->pcache.tree_data, it->pcache.tree_size);
1108                        add_pbase_object(&tree, name, cmplen, name);
1109                }
1110        }
1111}
1112
1113static void add_preferred_base(unsigned char *sha1)
1114{
1115        struct pbase_tree *it;
1116        void *data;
1117        unsigned long size;
1118        unsigned char tree_sha1[20];
1119
1120        if (window <= num_preferred_base++)
1121                return;
1122
1123        data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
1124        if (!data)
1125                return;
1126
1127        for (it = pbase_tree; it; it = it->next) {
1128                if (!hashcmp(it->pcache.sha1, tree_sha1)) {
1129                        free(data);
1130                        return;
1131                }
1132        }
1133
1134        it = xcalloc(1, sizeof(*it));
1135        it->next = pbase_tree;
1136        pbase_tree = it;
1137
1138        hashcpy(it->pcache.sha1, tree_sha1);
1139        it->pcache.tree_data = data;
1140        it->pcache.tree_size = size;
1141}
1142
1143static void cleanup_preferred_base(void)
1144{
1145        struct pbase_tree *it;
1146        unsigned i;
1147
1148        it = pbase_tree;
1149        pbase_tree = NULL;
1150        while (it) {
1151                struct pbase_tree *this = it;
1152                it = this->next;
1153                free(this->pcache.tree_data);
1154                free(this);
1155        }
1156
1157        for (i = 0; i < ARRAY_SIZE(pbase_tree_cache); i++) {
1158                if (!pbase_tree_cache[i])
1159                        continue;
1160                free(pbase_tree_cache[i]->tree_data);
1161                free(pbase_tree_cache[i]);
1162                pbase_tree_cache[i] = NULL;
1163        }
1164
1165        free(done_pbase_paths);
1166        done_pbase_paths = NULL;
1167        done_pbase_paths_num = done_pbase_paths_alloc = 0;
1168}
1169
1170static void check_object(struct object_entry *entry)
1171{
1172        if (entry->in_pack) {
1173                struct packed_git *p = entry->in_pack;
1174                struct pack_window *w_curs = NULL;
1175                const unsigned char *base_ref = NULL;
1176                struct object_entry *base_entry;
1177                unsigned long used, used_0;
1178                unsigned long avail;
1179                off_t ofs;
1180                unsigned char *buf, c;
1181
1182                buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
1183
1184                /*
1185                 * We want in_pack_type even if we do not reuse delta
1186                 * since non-delta representations could still be reused.
1187                 */
1188                used = unpack_object_header_buffer(buf, avail,
1189                                                   &entry->in_pack_type,
1190                                                   &entry->size);
1191                if (used == 0)
1192                        goto give_up;
1193
1194                /*
1195                 * Determine if this is a delta and if so whether we can
1196                 * reuse it or not.  Otherwise let's find out as cheaply as
1197                 * possible what the actual type and size for this object is.
1198                 */
1199                switch (entry->in_pack_type) {
1200                default:
1201                        /* Not a delta hence we've already got all we need. */
1202                        entry->type = entry->in_pack_type;
1203                        entry->in_pack_header_size = used;
1204                        if (entry->type < OBJ_COMMIT || entry->type > OBJ_BLOB)
1205                                goto give_up;
1206                        unuse_pack(&w_curs);
1207                        return;
1208                case OBJ_REF_DELTA:
1209                        if (reuse_delta && !entry->preferred_base)
1210                                base_ref = use_pack(p, &w_curs,
1211                                                entry->in_pack_offset + used, NULL);
1212                        entry->in_pack_header_size = used + 20;
1213                        break;
1214                case OBJ_OFS_DELTA:
1215                        buf = use_pack(p, &w_curs,
1216                                       entry->in_pack_offset + used, NULL);
1217                        used_0 = 0;
1218                        c = buf[used_0++];
1219                        ofs = c & 127;
1220                        while (c & 128) {
1221                                ofs += 1;
1222                                if (!ofs || MSB(ofs, 7)) {
1223                                        error("delta base offset overflow in pack for %s",
1224                                              sha1_to_hex(entry->idx.sha1));
1225                                        goto give_up;
1226                                }
1227                                c = buf[used_0++];
1228                                ofs = (ofs << 7) + (c & 127);
1229                        }
1230                        ofs = entry->in_pack_offset - ofs;
1231                        if (ofs <= 0 || ofs >= entry->in_pack_offset) {
1232                                error("delta base offset out of bound for %s",
1233                                      sha1_to_hex(entry->idx.sha1));
1234                                goto give_up;
1235                        }
1236                        if (reuse_delta && !entry->preferred_base) {
1237                                struct revindex_entry *revidx;
1238                                revidx = find_pack_revindex(p, ofs);
1239                                if (!revidx)
1240                                        goto give_up;
1241                                base_ref = nth_packed_object_sha1(p, revidx->nr);
1242                        }
1243                        entry->in_pack_header_size = used + used_0;
1244                        break;
1245                }
1246
1247                if (base_ref && (base_entry = locate_object_entry(base_ref))) {
1248                        /*
1249                         * If base_ref was set above that means we wish to
1250                         * reuse delta data, and we even found that base
1251                         * in the list of objects we want to pack. Goodie!
1252                         *
1253                         * Depth value does not matter - find_deltas() will
1254                         * never consider reused delta as the base object to
1255                         * deltify other objects against, in order to avoid
1256                         * circular deltas.
1257                         */
1258                        entry->type = entry->in_pack_type;
1259                        entry->delta = base_entry;
1260                        entry->delta_size = entry->size;
1261                        entry->delta_sibling = base_entry->delta_child;
1262                        base_entry->delta_child = entry;
1263                        unuse_pack(&w_curs);
1264                        return;
1265                }
1266
1267                if (entry->type) {
1268                        /*
1269                         * This must be a delta and we already know what the
1270                         * final object type is.  Let's extract the actual
1271                         * object size from the delta header.
1272                         */
1273                        entry->size = get_size_from_delta(p, &w_curs,
1274                                        entry->in_pack_offset + entry->in_pack_header_size);
1275                        if (entry->size == 0)
1276                                goto give_up;
1277                        unuse_pack(&w_curs);
1278                        return;
1279                }
1280
1281                /*
1282                 * No choice but to fall back to the recursive delta walk
1283                 * with sha1_object_info() to find about the object type
1284                 * at this point...
1285                 */
1286                give_up:
1287                unuse_pack(&w_curs);
1288        }
1289
1290        entry->type = sha1_object_info(entry->idx.sha1, &entry->size);
1291        /*
1292         * The error condition is checked in prepare_pack().  This is
1293         * to permit a missing preferred base object to be ignored
1294         * as a preferred base.  Doing so can result in a larger
1295         * pack file, but the transfer will still take place.
1296         */
1297}
1298
1299static int pack_offset_sort(const void *_a, const void *_b)
1300{
1301        const struct object_entry *a = *(struct object_entry **)_a;
1302        const struct object_entry *b = *(struct object_entry **)_b;
1303
1304        /* avoid filesystem trashing with loose objects */
1305        if (!a->in_pack && !b->in_pack)
1306                return hashcmp(a->idx.sha1, b->idx.sha1);
1307
1308        if (a->in_pack < b->in_pack)
1309                return -1;
1310        if (a->in_pack > b->in_pack)
1311                return 1;
1312        return a->in_pack_offset < b->in_pack_offset ? -1 :
1313                        (a->in_pack_offset > b->in_pack_offset);
1314}
1315
1316static void get_object_details(void)
1317{
1318        uint32_t i;
1319        struct object_entry **sorted_by_offset;
1320
1321        sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
1322        for (i = 0; i < nr_objects; i++)
1323                sorted_by_offset[i] = objects + i;
1324        qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
1325
1326        for (i = 0; i < nr_objects; i++) {
1327                struct object_entry *entry = sorted_by_offset[i];
1328                check_object(entry);
1329                if (big_file_threshold <= entry->size)
1330                        entry->no_try_delta = 1;
1331        }
1332
1333        free(sorted_by_offset);
1334}
1335
1336/*
1337 * We search for deltas in a list sorted by type, by filename hash, and then
1338 * by size, so that we see progressively smaller and smaller files.
1339 * That's because we prefer deltas to be from the bigger file
1340 * to the smaller -- deletes are potentially cheaper, but perhaps
1341 * more importantly, the bigger file is likely the more recent
1342 * one.  The deepest deltas are therefore the oldest objects which are
1343 * less susceptible to be accessed often.
1344 */
1345static int type_size_sort(const void *_a, const void *_b)
1346{
1347        const struct object_entry *a = *(struct object_entry **)_a;
1348        const struct object_entry *b = *(struct object_entry **)_b;
1349
1350        if (a->type > b->type)
1351                return -1;
1352        if (a->type < b->type)
1353                return 1;
1354        if (a->hash > b->hash)
1355                return -1;
1356        if (a->hash < b->hash)
1357                return 1;
1358        if (a->preferred_base > b->preferred_base)
1359                return -1;
1360        if (a->preferred_base < b->preferred_base)
1361                return 1;
1362        if (a->size > b->size)
1363                return -1;
1364        if (a->size < b->size)
1365                return 1;
1366        return a < b ? -1 : (a > b);  /* newest first */
1367}
1368
1369struct unpacked {
1370        struct object_entry *entry;
1371        void *data;
1372        struct delta_index *index;
1373        unsigned depth;
1374};
1375
1376static int delta_cacheable(unsigned long src_size, unsigned long trg_size,
1377                           unsigned long delta_size)
1378{
1379        if (max_delta_cache_size && delta_cache_size + delta_size > max_delta_cache_size)
1380                return 0;
1381
1382        if (delta_size < cache_max_small_delta_size)
1383                return 1;
1384
1385        /* cache delta, if objects are large enough compared to delta size */
1386        if ((src_size >> 20) + (trg_size >> 21) > (delta_size >> 10))
1387                return 1;
1388
1389        return 0;
1390}
1391
1392#ifndef NO_PTHREADS
1393
1394static pthread_mutex_t read_mutex;
1395#define read_lock()             pthread_mutex_lock(&read_mutex)
1396#define read_unlock()           pthread_mutex_unlock(&read_mutex)
1397
1398static pthread_mutex_t cache_mutex;
1399#define cache_lock()            pthread_mutex_lock(&cache_mutex)
1400#define cache_unlock()          pthread_mutex_unlock(&cache_mutex)
1401
1402static pthread_mutex_t progress_mutex;
1403#define progress_lock()         pthread_mutex_lock(&progress_mutex)
1404#define progress_unlock()       pthread_mutex_unlock(&progress_mutex)
1405
1406#else
1407
1408#define read_lock()             (void)0
1409#define read_unlock()           (void)0
1410#define cache_lock()            (void)0
1411#define cache_unlock()          (void)0
1412#define progress_lock()         (void)0
1413#define progress_unlock()       (void)0
1414
1415#endif
1416
1417static int try_delta(struct unpacked *trg, struct unpacked *src,
1418                     unsigned max_depth, unsigned long *mem_usage)
1419{
1420        struct object_entry *trg_entry = trg->entry;
1421        struct object_entry *src_entry = src->entry;
1422        unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz;
1423        unsigned ref_depth;
1424        enum object_type type;
1425        void *delta_buf;
1426
1427        /* Don't bother doing diffs between different types */
1428        if (trg_entry->type != src_entry->type)
1429                return -1;
1430
1431        /*
1432         * We do not bother to try a delta that we discarded on an
1433         * earlier try, but only when reusing delta data.  Note that
1434         * src_entry that is marked as the preferred_base should always
1435         * be considered, as even if we produce a suboptimal delta against
1436         * it, we will still save the transfer cost, as we already know
1437         * the other side has it and we won't send src_entry at all.
1438         */
1439        if (reuse_delta && trg_entry->in_pack &&
1440            trg_entry->in_pack == src_entry->in_pack &&
1441            !src_entry->preferred_base &&
1442            trg_entry->in_pack_type != OBJ_REF_DELTA &&
1443            trg_entry->in_pack_type != OBJ_OFS_DELTA)
1444                return 0;
1445
1446        /* Let's not bust the allowed depth. */
1447        if (src->depth >= max_depth)
1448                return 0;
1449
1450        /* Now some size filtering heuristics. */
1451        trg_size = trg_entry->size;
1452        if (!trg_entry->delta) {
1453                max_size = trg_size/2 - 20;
1454                ref_depth = 1;
1455        } else {
1456                max_size = trg_entry->delta_size;
1457                ref_depth = trg->depth;
1458        }
1459        max_size = (uint64_t)max_size * (max_depth - src->depth) /
1460                                                (max_depth - ref_depth + 1);
1461        if (max_size == 0)
1462                return 0;
1463        src_size = src_entry->size;
1464        sizediff = src_size < trg_size ? trg_size - src_size : 0;
1465        if (sizediff >= max_size)
1466                return 0;
1467        if (trg_size < src_size / 32)
1468                return 0;
1469
1470        /* Load data if not already done */
1471        if (!trg->data) {
1472                read_lock();
1473                trg->data = read_sha1_file(trg_entry->idx.sha1, &type, &sz);
1474                read_unlock();
1475                if (!trg->data)
1476                        die("object %s cannot be read",
1477                            sha1_to_hex(trg_entry->idx.sha1));
1478                if (sz != trg_size)
1479                        die("object %s inconsistent object length (%lu vs %lu)",
1480                            sha1_to_hex(trg_entry->idx.sha1), sz, trg_size);
1481                *mem_usage += sz;
1482        }
1483        if (!src->data) {
1484                read_lock();
1485                src->data = read_sha1_file(src_entry->idx.sha1, &type, &sz);
1486                read_unlock();
1487                if (!src->data) {
1488                        if (src_entry->preferred_base) {
1489                                static int warned = 0;
1490                                if (!warned++)
1491                                        warning("object %s cannot be read",
1492                                                sha1_to_hex(src_entry->idx.sha1));
1493                                /*
1494                                 * Those objects are not included in the
1495                                 * resulting pack.  Be resilient and ignore
1496                                 * them if they can't be read, in case the
1497                                 * pack could be created nevertheless.
1498                                 */
1499                                return 0;
1500                        }
1501                        die("object %s cannot be read",
1502                            sha1_to_hex(src_entry->idx.sha1));
1503                }
1504                if (sz != src_size)
1505                        die("object %s inconsistent object length (%lu vs %lu)",
1506                            sha1_to_hex(src_entry->idx.sha1), sz, src_size);
1507                *mem_usage += sz;
1508        }
1509        if (!src->index) {
1510                src->index = create_delta_index(src->data, src_size);
1511                if (!src->index) {
1512                        static int warned = 0;
1513                        if (!warned++)
1514                                warning("suboptimal pack - out of memory");
1515                        return 0;
1516                }
1517                *mem_usage += sizeof_delta_index(src->index);
1518        }
1519
1520        delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size);
1521        if (!delta_buf)
1522                return 0;
1523
1524        if (trg_entry->delta) {
1525                /* Prefer only shallower same-sized deltas. */
1526                if (delta_size == trg_entry->delta_size &&
1527                    src->depth + 1 >= trg->depth) {
1528                        free(delta_buf);
1529                        return 0;
1530                }
1531        }
1532
1533        /*
1534         * Handle memory allocation outside of the cache
1535         * accounting lock.  Compiler will optimize the strangeness
1536         * away when NO_PTHREADS is defined.
1537         */
1538        free(trg_entry->delta_data);
1539        cache_lock();
1540        if (trg_entry->delta_data) {
1541                delta_cache_size -= trg_entry->delta_size;
1542                trg_entry->delta_data = NULL;
1543        }
1544        if (delta_cacheable(src_size, trg_size, delta_size)) {
1545                delta_cache_size += delta_size;
1546                cache_unlock();
1547                trg_entry->delta_data = xrealloc(delta_buf, delta_size);
1548        } else {
1549                cache_unlock();
1550                free(delta_buf);
1551        }
1552
1553        trg_entry->delta = src_entry;
1554        trg_entry->delta_size = delta_size;
1555        trg->depth = src->depth + 1;
1556
1557        return 1;
1558}
1559
1560static unsigned int check_delta_limit(struct object_entry *me, unsigned int n)
1561{
1562        struct object_entry *child = me->delta_child;
1563        unsigned int m = n;
1564        while (child) {
1565                unsigned int c = check_delta_limit(child, n + 1);
1566                if (m < c)
1567                        m = c;
1568                child = child->delta_sibling;
1569        }
1570        return m;
1571}
1572
1573static unsigned long free_unpacked(struct unpacked *n)
1574{
1575        unsigned long freed_mem = sizeof_delta_index(n->index);
1576        free_delta_index(n->index);
1577        n->index = NULL;
1578        if (n->data) {
1579                freed_mem += n->entry->size;
1580                free(n->data);
1581                n->data = NULL;
1582        }
1583        n->entry = NULL;
1584        n->depth = 0;
1585        return freed_mem;
1586}
1587
1588static void find_deltas(struct object_entry **list, unsigned *list_size,
1589                        int window, int depth, unsigned *processed)
1590{
1591        uint32_t i, idx = 0, count = 0;
1592        struct unpacked *array;
1593        unsigned long mem_usage = 0;
1594
1595        array = xcalloc(window, sizeof(struct unpacked));
1596
1597        for (;;) {
1598                struct object_entry *entry;
1599                struct unpacked *n = array + idx;
1600                int j, max_depth, best_base = -1;
1601
1602                progress_lock();
1603                if (!*list_size) {
1604                        progress_unlock();
1605                        break;
1606                }
1607                entry = *list++;
1608                (*list_size)--;
1609                if (!entry->preferred_base) {
1610                        (*processed)++;
1611                        display_progress(progress_state, *processed);
1612                }
1613                progress_unlock();
1614
1615                mem_usage -= free_unpacked(n);
1616                n->entry = entry;
1617
1618                while (window_memory_limit &&
1619                       mem_usage > window_memory_limit &&
1620                       count > 1) {
1621                        uint32_t tail = (idx + window - count) % window;
1622                        mem_usage -= free_unpacked(array + tail);
1623                        count--;
1624                }
1625
1626                /* We do not compute delta to *create* objects we are not
1627                 * going to pack.
1628                 */
1629                if (entry->preferred_base)
1630                        goto next;
1631
1632                /*
1633                 * If the current object is at pack edge, take the depth the
1634                 * objects that depend on the current object into account
1635                 * otherwise they would become too deep.
1636                 */
1637                max_depth = depth;
1638                if (entry->delta_child) {
1639                        max_depth -= check_delta_limit(entry, 0);
1640                        if (max_depth <= 0)
1641                                goto next;
1642                }
1643
1644                j = window;
1645                while (--j > 0) {
1646                        int ret;
1647                        uint32_t other_idx = idx + j;
1648                        struct unpacked *m;
1649                        if (other_idx >= window)
1650                                other_idx -= window;
1651                        m = array + other_idx;
1652                        if (!m->entry)
1653                                break;
1654                        ret = try_delta(n, m, max_depth, &mem_usage);
1655                        if (ret < 0)
1656                                break;
1657                        else if (ret > 0)
1658                                best_base = other_idx;
1659                }
1660
1661                /*
1662                 * If we decided to cache the delta data, then it is best
1663                 * to compress it right away.  First because we have to do
1664                 * it anyway, and doing it here while we're threaded will
1665                 * save a lot of time in the non threaded write phase,
1666                 * as well as allow for caching more deltas within
1667                 * the same cache size limit.
1668                 * ...
1669                 * But only if not writing to stdout, since in that case
1670                 * the network is most likely throttling writes anyway,
1671                 * and therefore it is best to go to the write phase ASAP
1672                 * instead, as we can afford spending more time compressing
1673                 * between writes at that moment.
1674                 */
1675                if (entry->delta_data && !pack_to_stdout) {
1676                        entry->z_delta_size = do_compress(&entry->delta_data,
1677                                                          entry->delta_size);
1678                        cache_lock();
1679                        delta_cache_size -= entry->delta_size;
1680                        delta_cache_size += entry->z_delta_size;
1681                        cache_unlock();
1682                }
1683
1684                /* if we made n a delta, and if n is already at max
1685                 * depth, leaving it in the window is pointless.  we
1686                 * should evict it first.
1687                 */
1688                if (entry->delta && max_depth <= n->depth)
1689                        continue;
1690
1691                /*
1692                 * Move the best delta base up in the window, after the
1693                 * currently deltified object, to keep it longer.  It will
1694                 * be the first base object to be attempted next.
1695                 */
1696                if (entry->delta) {
1697                        struct unpacked swap = array[best_base];
1698                        int dist = (window + idx - best_base) % window;
1699                        int dst = best_base;
1700                        while (dist--) {
1701                                int src = (dst + 1) % window;
1702                                array[dst] = array[src];
1703                                dst = src;
1704                        }
1705                        array[dst] = swap;
1706                }
1707
1708                next:
1709                idx++;
1710                if (count + 1 < window)
1711                        count++;
1712                if (idx >= window)
1713                        idx = 0;
1714        }
1715
1716        for (i = 0; i < window; ++i) {
1717                free_delta_index(array[i].index);
1718                free(array[i].data);
1719        }
1720        free(array);
1721}
1722
1723#ifndef NO_PTHREADS
1724
1725static void try_to_free_from_threads(size_t size)
1726{
1727        read_lock();
1728        release_pack_memory(size, -1);
1729        read_unlock();
1730}
1731
1732static try_to_free_t old_try_to_free_routine;
1733
1734/*
1735 * The main thread waits on the condition that (at least) one of the workers
1736 * has stopped working (which is indicated in the .working member of
1737 * struct thread_params).
1738 * When a work thread has completed its work, it sets .working to 0 and
1739 * signals the main thread and waits on the condition that .data_ready
1740 * becomes 1.
1741 */
1742
1743struct thread_params {
1744        pthread_t thread;
1745        struct object_entry **list;
1746        unsigned list_size;
1747        unsigned remaining;
1748        int window;
1749        int depth;
1750        int working;
1751        int data_ready;
1752        pthread_mutex_t mutex;
1753        pthread_cond_t cond;
1754        unsigned *processed;
1755};
1756
1757static pthread_cond_t progress_cond;
1758
1759/*
1760 * Mutex and conditional variable can't be statically-initialized on Windows.
1761 */
1762static void init_threaded_search(void)
1763{
1764        init_recursive_mutex(&read_mutex);
1765        pthread_mutex_init(&cache_mutex, NULL);
1766        pthread_mutex_init(&progress_mutex, NULL);
1767        pthread_cond_init(&progress_cond, NULL);
1768        old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);
1769}
1770
1771static void cleanup_threaded_search(void)
1772{
1773        set_try_to_free_routine(old_try_to_free_routine);
1774        pthread_cond_destroy(&progress_cond);
1775        pthread_mutex_destroy(&read_mutex);
1776        pthread_mutex_destroy(&cache_mutex);
1777        pthread_mutex_destroy(&progress_mutex);
1778}
1779
1780static void *threaded_find_deltas(void *arg)
1781{
1782        struct thread_params *me = arg;
1783
1784        while (me->remaining) {
1785                find_deltas(me->list, &me->remaining,
1786                            me->window, me->depth, me->processed);
1787
1788                progress_lock();
1789                me->working = 0;
1790                pthread_cond_signal(&progress_cond);
1791                progress_unlock();
1792
1793                /*
1794                 * We must not set ->data_ready before we wait on the
1795                 * condition because the main thread may have set it to 1
1796                 * before we get here. In order to be sure that new
1797                 * work is available if we see 1 in ->data_ready, it
1798                 * was initialized to 0 before this thread was spawned
1799                 * and we reset it to 0 right away.
1800                 */
1801                pthread_mutex_lock(&me->mutex);
1802                while (!me->data_ready)
1803                        pthread_cond_wait(&me->cond, &me->mutex);
1804                me->data_ready = 0;
1805                pthread_mutex_unlock(&me->mutex);
1806        }
1807        /* leave ->working 1 so that this doesn't get more work assigned */
1808        return NULL;
1809}
1810
1811static void ll_find_deltas(struct object_entry **list, unsigned list_size,
1812                           int window, int depth, unsigned *processed)
1813{
1814        struct thread_params *p;
1815        int i, ret, active_threads = 0;
1816
1817        init_threaded_search();
1818
1819        if (!delta_search_threads)      /* --threads=0 means autodetect */
1820                delta_search_threads = online_cpus();
1821        if (delta_search_threads <= 1) {
1822                find_deltas(list, &list_size, window, depth, processed);
1823                cleanup_threaded_search();
1824                return;
1825        }
1826        if (progress > pack_to_stdout)
1827                fprintf(stderr, "Delta compression using up to %d threads.\n",
1828                                delta_search_threads);
1829        p = xcalloc(delta_search_threads, sizeof(*p));
1830
1831        /* Partition the work amongst work threads. */
1832        for (i = 0; i < delta_search_threads; i++) {
1833                unsigned sub_size = list_size / (delta_search_threads - i);
1834
1835                /* don't use too small segments or no deltas will be found */
1836                if (sub_size < 2*window && i+1 < delta_search_threads)
1837                        sub_size = 0;
1838
1839                p[i].window = window;
1840                p[i].depth = depth;
1841                p[i].processed = processed;
1842                p[i].working = 1;
1843                p[i].data_ready = 0;
1844
1845                /* try to split chunks on "path" boundaries */
1846                while (sub_size && sub_size < list_size &&
1847                       list[sub_size]->hash &&
1848                       list[sub_size]->hash == list[sub_size-1]->hash)
1849                        sub_size++;
1850
1851                p[i].list = list;
1852                p[i].list_size = sub_size;
1853                p[i].remaining = sub_size;
1854
1855                list += sub_size;
1856                list_size -= sub_size;
1857        }
1858
1859        /* Start work threads. */
1860        for (i = 0; i < delta_search_threads; i++) {
1861                if (!p[i].list_size)
1862                        continue;
1863                pthread_mutex_init(&p[i].mutex, NULL);
1864                pthread_cond_init(&p[i].cond, NULL);
1865                ret = pthread_create(&p[i].thread, NULL,
1866                                     threaded_find_deltas, &p[i]);
1867                if (ret)
1868                        die("unable to create thread: %s", strerror(ret));
1869                active_threads++;
1870        }
1871
1872        /*
1873         * Now let's wait for work completion.  Each time a thread is done
1874         * with its work, we steal half of the remaining work from the
1875         * thread with the largest number of unprocessed objects and give
1876         * it to that newly idle thread.  This ensure good load balancing
1877         * until the remaining object list segments are simply too short
1878         * to be worth splitting anymore.
1879         */
1880        while (active_threads) {
1881                struct thread_params *target = NULL;
1882                struct thread_params *victim = NULL;
1883                unsigned sub_size = 0;
1884
1885                progress_lock();
1886                for (;;) {
1887                        for (i = 0; !target && i < delta_search_threads; i++)
1888                                if (!p[i].working)
1889                                        target = &p[i];
1890                        if (target)
1891                                break;
1892                        pthread_cond_wait(&progress_cond, &progress_mutex);
1893                }
1894
1895                for (i = 0; i < delta_search_threads; i++)
1896                        if (p[i].remaining > 2*window &&
1897                            (!victim || victim->remaining < p[i].remaining))
1898                                victim = &p[i];
1899                if (victim) {
1900                        sub_size = victim->remaining / 2;
1901                        list = victim->list + victim->list_size - sub_size;
1902                        while (sub_size && list[0]->hash &&
1903                               list[0]->hash == list[-1]->hash) {
1904                                list++;
1905                                sub_size--;
1906                        }
1907                        if (!sub_size) {
1908                                /*
1909                                 * It is possible for some "paths" to have
1910                                 * so many objects that no hash boundary
1911                                 * might be found.  Let's just steal the
1912                                 * exact half in that case.
1913                                 */
1914                                sub_size = victim->remaining / 2;
1915                                list -= sub_size;
1916                        }
1917                        target->list = list;
1918                        victim->list_size -= sub_size;
1919                        victim->remaining -= sub_size;
1920                }
1921                target->list_size = sub_size;
1922                target->remaining = sub_size;
1923                target->working = 1;
1924                progress_unlock();
1925
1926                pthread_mutex_lock(&target->mutex);
1927                target->data_ready = 1;
1928                pthread_cond_signal(&target->cond);
1929                pthread_mutex_unlock(&target->mutex);
1930
1931                if (!sub_size) {
1932                        pthread_join(target->thread, NULL);
1933                        pthread_cond_destroy(&target->cond);
1934                        pthread_mutex_destroy(&target->mutex);
1935                        active_threads--;
1936                }
1937        }
1938        cleanup_threaded_search();
1939        free(p);
1940}
1941
1942#else
1943#define ll_find_deltas(l, s, w, d, p)   find_deltas(l, &s, w, d, p)
1944#endif
1945
1946static int add_ref_tag(const char *path, const unsigned char *sha1, int flag, void *cb_data)
1947{
1948        unsigned char peeled[20];
1949
1950        if (!prefixcmp(path, "refs/tags/") && /* is a tag? */
1951            !peel_ref(path, peeled)        && /* peelable? */
1952            !is_null_sha1(peeled)          && /* annotated tag? */
1953            locate_object_entry(peeled))      /* object packed? */
1954                add_object_entry(sha1, OBJ_TAG, NULL, 0);
1955        return 0;
1956}
1957
1958static void prepare_pack(int window, int depth)
1959{
1960        struct object_entry **delta_list;
1961        uint32_t i, nr_deltas;
1962        unsigned n;
1963
1964        get_object_details();
1965
1966        /*
1967         * If we're locally repacking then we need to be doubly careful
1968         * from now on in order to make sure no stealth corruption gets
1969         * propagated to the new pack.  Clients receiving streamed packs
1970         * should validate everything they get anyway so no need to incur
1971         * the additional cost here in that case.
1972         */
1973        if (!pack_to_stdout)
1974                do_check_packed_object_crc = 1;
1975
1976        if (!nr_objects || !window || !depth)
1977                return;
1978
1979        delta_list = xmalloc(nr_objects * sizeof(*delta_list));
1980        nr_deltas = n = 0;
1981
1982        for (i = 0; i < nr_objects; i++) {
1983                struct object_entry *entry = objects + i;
1984
1985                if (entry->delta)
1986                        /* This happens if we decided to reuse existing
1987                         * delta from a pack.  "reuse_delta &&" is implied.
1988                         */
1989                        continue;
1990
1991                if (entry->size < 50)
1992                        continue;
1993
1994                if (entry->no_try_delta)
1995                        continue;
1996
1997                if (!entry->preferred_base) {
1998                        nr_deltas++;
1999                        if (entry->type < 0)
2000                                die("unable to get type of object %s",
2001                                    sha1_to_hex(entry->idx.sha1));
2002                } else {
2003                        if (entry->type < 0) {
2004                                /*
2005                                 * This object is not found, but we
2006                                 * don't have to include it anyway.
2007                                 */
2008                                continue;
2009                        }
2010                }
2011
2012                delta_list[n++] = entry;
2013        }
2014
2015        if (nr_deltas && n > 1) {
2016                unsigned nr_done = 0;
2017                if (progress)
2018                        progress_state = start_progress("Compressing objects",
2019                                                        nr_deltas);
2020                qsort(delta_list, n, sizeof(*delta_list), type_size_sort);
2021                ll_find_deltas(delta_list, n, window+1, depth, &nr_done);
2022                stop_progress(&progress_state);
2023                if (nr_done != nr_deltas)
2024                        die("inconsistency with delta count");
2025        }
2026        free(delta_list);
2027}
2028
2029static int git_pack_config(const char *k, const char *v, void *cb)
2030{
2031        if (!strcmp(k, "pack.window")) {
2032                window = git_config_int(k, v);
2033                return 0;
2034        }
2035        if (!strcmp(k, "pack.windowmemory")) {
2036                window_memory_limit = git_config_ulong(k, v);
2037                return 0;
2038        }
2039        if (!strcmp(k, "pack.depth")) {
2040                depth = git_config_int(k, v);
2041                return 0;
2042        }
2043        if (!strcmp(k, "pack.compression")) {
2044                int level = git_config_int(k, v);
2045                if (level == -1)
2046                        level = Z_DEFAULT_COMPRESSION;
2047                else if (level < 0 || level > Z_BEST_COMPRESSION)
2048                        die("bad pack compression level %d", level);
2049                pack_compression_level = level;
2050                pack_compression_seen = 1;
2051                return 0;
2052        }
2053        if (!strcmp(k, "pack.deltacachesize")) {
2054                max_delta_cache_size = git_config_int(k, v);
2055                return 0;
2056        }
2057        if (!strcmp(k, "pack.deltacachelimit")) {
2058                cache_max_small_delta_size = git_config_int(k, v);
2059                return 0;
2060        }
2061        if (!strcmp(k, "pack.threads")) {
2062                delta_search_threads = git_config_int(k, v);
2063                if (delta_search_threads < 0)
2064                        die("invalid number of threads specified (%d)",
2065                            delta_search_threads);
2066#ifdef NO_PTHREADS
2067                if (delta_search_threads != 1)
2068                        warning("no threads support, ignoring %s", k);
2069#endif
2070                return 0;
2071        }
2072        if (!strcmp(k, "pack.indexversion")) {
2073                pack_idx_opts.version = git_config_int(k, v);
2074                if (pack_idx_opts.version > 2)
2075                        die("bad pack.indexversion=%"PRIu32,
2076                            pack_idx_opts.version);
2077                return 0;
2078        }
2079        return git_default_config(k, v, cb);
2080}
2081
2082static void read_object_list_from_stdin(void)
2083{
2084        char line[40 + 1 + PATH_MAX + 2];
2085        unsigned char sha1[20];
2086
2087        for (;;) {
2088                if (!fgets(line, sizeof(line), stdin)) {
2089                        if (feof(stdin))
2090                                break;
2091                        if (!ferror(stdin))
2092                                die("fgets returned NULL, not EOF, not error!");
2093                        if (errno != EINTR)
2094                                die_errno("fgets");
2095                        clearerr(stdin);
2096                        continue;
2097                }
2098                if (line[0] == '-') {
2099                        if (get_sha1_hex(line+1, sha1))
2100                                die("expected edge sha1, got garbage:\n %s",
2101                                    line);
2102                        add_preferred_base(sha1);
2103                        continue;
2104                }
2105                if (get_sha1_hex(line, sha1))
2106                        die("expected sha1, got garbage:\n %s", line);
2107
2108                add_preferred_base_object(line+41);
2109                add_object_entry(sha1, 0, line+41, 0);
2110        }
2111}
2112
2113#define OBJECT_ADDED (1u<<20)
2114
2115static void show_commit(struct commit *commit, void *data)
2116{
2117        add_object_entry(commit->object.sha1, OBJ_COMMIT, NULL, 0);
2118        commit->object.flags |= OBJECT_ADDED;
2119}
2120
2121static void show_object(struct object *obj,
2122                        const struct name_path *path, const char *last,
2123                        void *data)
2124{
2125        char *name = path_name(path, last);
2126
2127        add_preferred_base_object(name);
2128        add_object_entry(obj->sha1, obj->type, name, 0);
2129        obj->flags |= OBJECT_ADDED;
2130
2131        /*
2132         * We will have generated the hash from the name,
2133         * but not saved a pointer to it - we can free it
2134         */
2135        free((char *)name);
2136}
2137
2138static void show_edge(struct commit *commit)
2139{
2140        add_preferred_base(commit->object.sha1);
2141}
2142
2143struct in_pack_object {
2144        off_t offset;
2145        struct object *object;
2146};
2147
2148struct in_pack {
2149        int alloc;
2150        int nr;
2151        struct in_pack_object *array;
2152};
2153
2154static void mark_in_pack_object(struct object *object, struct packed_git *p, struct in_pack *in_pack)
2155{
2156        in_pack->array[in_pack->nr].offset = find_pack_entry_one(object->sha1, p);
2157        in_pack->array[in_pack->nr].object = object;
2158        in_pack->nr++;
2159}
2160
2161/*
2162 * Compare the objects in the offset order, in order to emulate the
2163 * "git rev-list --objects" output that produced the pack originally.
2164 */
2165static int ofscmp(const void *a_, const void *b_)
2166{
2167        struct in_pack_object *a = (struct in_pack_object *)a_;
2168        struct in_pack_object *b = (struct in_pack_object *)b_;
2169
2170        if (a->offset < b->offset)
2171                return -1;
2172        else if (a->offset > b->offset)
2173                return 1;
2174        else
2175                return hashcmp(a->object->sha1, b->object->sha1);
2176}
2177
2178static void add_objects_in_unpacked_packs(struct rev_info *revs)
2179{
2180        struct packed_git *p;
2181        struct in_pack in_pack;
2182        uint32_t i;
2183
2184        memset(&in_pack, 0, sizeof(in_pack));
2185
2186        for (p = packed_git; p; p = p->next) {
2187                const unsigned char *sha1;
2188                struct object *o;
2189
2190                if (!p->pack_local || p->pack_keep)
2191                        continue;
2192                if (open_pack_index(p))
2193                        die("cannot open pack index");
2194
2195                ALLOC_GROW(in_pack.array,
2196                           in_pack.nr + p->num_objects,
2197                           in_pack.alloc);
2198
2199                for (i = 0; i < p->num_objects; i++) {
2200                        sha1 = nth_packed_object_sha1(p, i);
2201                        o = lookup_unknown_object(sha1);
2202                        if (!(o->flags & OBJECT_ADDED))
2203                                mark_in_pack_object(o, p, &in_pack);
2204                        o->flags |= OBJECT_ADDED;
2205                }
2206        }
2207
2208        if (in_pack.nr) {
2209                qsort(in_pack.array, in_pack.nr, sizeof(in_pack.array[0]),
2210                      ofscmp);
2211                for (i = 0; i < in_pack.nr; i++) {
2212                        struct object *o = in_pack.array[i].object;
2213                        add_object_entry(o->sha1, o->type, "", 0);
2214                }
2215        }
2216        free(in_pack.array);
2217}
2218
2219static int has_sha1_pack_kept_or_nonlocal(const unsigned char *sha1)
2220{
2221        static struct packed_git *last_found = (void *)1;
2222        struct packed_git *p;
2223
2224        p = (last_found != (void *)1) ? last_found : packed_git;
2225
2226        while (p) {
2227                if ((!p->pack_local || p->pack_keep) &&
2228                        find_pack_entry_one(sha1, p)) {
2229                        last_found = p;
2230                        return 1;
2231                }
2232                if (p == last_found)
2233                        p = packed_git;
2234                else
2235                        p = p->next;
2236                if (p == last_found)
2237                        p = p->next;
2238        }
2239        return 0;
2240}
2241
2242static void loosen_unused_packed_objects(struct rev_info *revs)
2243{
2244        struct packed_git *p;
2245        uint32_t i;
2246        const unsigned char *sha1;
2247
2248        for (p = packed_git; p; p = p->next) {
2249                if (!p->pack_local || p->pack_keep)
2250                        continue;
2251
2252                if (open_pack_index(p))
2253                        die("cannot open pack index");
2254
2255                for (i = 0; i < p->num_objects; i++) {
2256                        sha1 = nth_packed_object_sha1(p, i);
2257                        if (!locate_object_entry(sha1) &&
2258                                !has_sha1_pack_kept_or_nonlocal(sha1))
2259                                if (force_object_loose(sha1, p->mtime))
2260                                        die("unable to force loose object");
2261                }
2262        }
2263}
2264
2265static void get_object_list(int ac, const char **av)
2266{
2267        struct rev_info revs;
2268        char line[1000];
2269        int flags = 0;
2270
2271        init_revisions(&revs, NULL);
2272        save_commit_buffer = 0;
2273        setup_revisions(ac, av, &revs, NULL);
2274
2275        while (fgets(line, sizeof(line), stdin) != NULL) {
2276                int len = strlen(line);
2277                if (len && line[len - 1] == '\n')
2278                        line[--len] = 0;
2279                if (!len)
2280                        break;
2281                if (*line == '-') {
2282                        if (!strcmp(line, "--not")) {
2283                                flags ^= UNINTERESTING;
2284                                continue;
2285                        }
2286                        die("not a rev '%s'", line);
2287                }
2288                if (handle_revision_arg(line, &revs, flags, 1))
2289                        die("bad revision '%s'", line);
2290        }
2291
2292        if (prepare_revision_walk(&revs))
2293                die("revision walk setup failed");
2294        mark_edges_uninteresting(revs.commits, &revs, show_edge);
2295        traverse_commit_list(&revs, show_commit, show_object, NULL);
2296
2297        if (keep_unreachable)
2298                add_objects_in_unpacked_packs(&revs);
2299        if (unpack_unreachable)
2300                loosen_unused_packed_objects(&revs);
2301}
2302
2303static int option_parse_index_version(const struct option *opt,
2304                                      const char *arg, int unset)
2305{
2306        char *c;
2307        const char *val = arg;
2308        pack_idx_opts.version = strtoul(val, &c, 10);
2309        if (pack_idx_opts.version > 2)
2310                die(_("unsupported index version %s"), val);
2311        if (*c == ',' && c[1])
2312                pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
2313        if (*c || pack_idx_opts.off32_limit & 0x80000000)
2314                die(_("bad index version '%s'"), val);
2315        return 0;
2316}
2317
2318static int option_parse_ulong(const struct option *opt,
2319                              const char *arg, int unset)
2320{
2321        if (unset)
2322                die(_("option %s does not accept negative form"),
2323                    opt->long_name);
2324
2325        if (!git_parse_ulong(arg, opt->value))
2326                die(_("unable to parse value '%s' for option %s"),
2327                    arg, opt->long_name);
2328        return 0;
2329}
2330
2331#define OPT_ULONG(s, l, v, h) \
2332        { OPTION_CALLBACK, (s), (l), (v), "n", (h),     \
2333          PARSE_OPT_NONEG, option_parse_ulong }
2334
2335int cmd_pack_objects(int argc, const char **argv, const char *prefix)
2336{
2337        int use_internal_rev_list = 0;
2338        int thin = 0;
2339        int all_progress_implied = 0;
2340        const char *rp_av[6];
2341        int rp_ac = 0;
2342        int rev_list_unpacked = 0, rev_list_all = 0, rev_list_reflog = 0;
2343        struct option pack_objects_options[] = {
2344                OPT_SET_INT('q', "quiet", &progress,
2345                            "do not show progress meter", 0),
2346                OPT_SET_INT(0, "progress", &progress,
2347                            "show progress meter", 1),
2348                OPT_SET_INT(0, "all-progress", &progress,
2349                            "show progress meter during object writing phase", 2),
2350                OPT_BOOL(0, "all-progress-implied",
2351                         &all_progress_implied,
2352                         "similar to --all-progress when progress meter is shown"),
2353                { OPTION_CALLBACK, 0, "index-version", NULL, "version[,offset]",
2354                  "write the pack index file in the specified idx format version",
2355                  0, option_parse_index_version },
2356                OPT_ULONG(0, "max-pack-size", &pack_size_limit,
2357                          "maximum size of each output pack file"),
2358                OPT_BOOL(0, "local", &local,
2359                         "ignore borrowed objects from alternate object store"),
2360                OPT_BOOL(0, "incremental", &incremental,
2361                         "ignore packed objects"),
2362                OPT_INTEGER(0, "window", &window,
2363                            "limit pack window by objects"),
2364                OPT_ULONG(0, "window-memory", &window_memory_limit,
2365                          "limit pack window by memory in addition to object limit"),
2366                OPT_INTEGER(0, "depth", &depth,
2367                            "maximum length of delta chain allowed in the resulting pack"),
2368                OPT_BOOL(0, "reuse-delta", &reuse_delta,
2369                         "reuse existing deltas"),
2370                OPT_BOOL(0, "reuse-object", &reuse_object,
2371                         "reuse existing objects"),
2372                OPT_BOOL(0, "delta-base-offset", &allow_ofs_delta,
2373                         "use OFS_DELTA objects"),
2374                OPT_INTEGER(0, "threads", &delta_search_threads,
2375                            "use threads when searching for best delta matches"),
2376                OPT_BOOL(0, "non-empty", &non_empty,
2377                         "do not create an empty pack output"),
2378                OPT_BOOL(0, "revs", &use_internal_rev_list,
2379                         "read revision arguments from standard input"),
2380                { OPTION_SET_INT, 0, "unpacked", &rev_list_unpacked, NULL,
2381                  "limit the objects to those that are not yet packed",
2382                  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2383                { OPTION_SET_INT, 0, "all", &rev_list_all, NULL,
2384                  "include objects reachable from any reference",
2385                  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2386                { OPTION_SET_INT, 0, "reflog", &rev_list_reflog, NULL,
2387                  "include objects referred by reflog entries",
2388                  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1 },
2389                OPT_BOOL(0, "stdout", &pack_to_stdout,
2390                         "output pack to stdout"),
2391                OPT_BOOL(0, "include-tag", &include_tag,
2392                         "include tag objects that refer to objects to be packed"),
2393                OPT_BOOL(0, "keep-unreachable", &keep_unreachable,
2394                         "keep unreachable objects"),
2395                OPT_BOOL(0, "unpack-unreachable", &unpack_unreachable,
2396                         "unpack unreachable objects"),
2397                OPT_BOOL(0, "thin", &thin,
2398                         "create thin packs"),
2399                OPT_BOOL(0, "honor-pack-keep", &ignore_packed_keep,
2400                         "ignore packs that have companion .keep file"),
2401                OPT_INTEGER(0, "compression", &pack_compression_level,
2402                            "pack compression level"),
2403                OPT_SET_INT(0, "keep-true-parents", &grafts_replace_parents,
2404                            "do not hide commits by grafts", 0),
2405                OPT_END(),
2406        };
2407
2408        read_replace_refs = 0;
2409
2410        reset_pack_idx_option(&pack_idx_opts);
2411        git_config(git_pack_config, NULL);
2412        if (!pack_compression_seen && core_compression_seen)
2413                pack_compression_level = core_compression_level;
2414
2415        progress = isatty(2);
2416        argc = parse_options(argc, argv, prefix, pack_objects_options,
2417                             pack_usage, 0);
2418
2419        if (argc) {
2420                base_name = argv[0];
2421                argc--;
2422        }
2423        if (pack_to_stdout != !base_name || argc)
2424                usage_with_options(pack_usage, pack_objects_options);
2425
2426        rp_av[rp_ac++] = "pack-objects";
2427        if (thin) {
2428                use_internal_rev_list = 1;
2429                rp_av[rp_ac++] = "--objects-edge";
2430        } else
2431                rp_av[rp_ac++] = "--objects";
2432
2433        if (rev_list_all) {
2434                use_internal_rev_list = 1;
2435                rp_av[rp_ac++] = "--all";
2436        }
2437        if (rev_list_reflog) {
2438                use_internal_rev_list = 1;
2439                rp_av[rp_ac++] = "--reflog";
2440        }
2441        if (rev_list_unpacked) {
2442                use_internal_rev_list = 1;
2443                rp_av[rp_ac++] = "--unpacked";
2444        }
2445
2446        if (!reuse_object)
2447                reuse_delta = 0;
2448        if (pack_compression_level == -1)
2449                pack_compression_level = Z_DEFAULT_COMPRESSION;
2450        else if (pack_compression_level < 0 || pack_compression_level > Z_BEST_COMPRESSION)
2451                die("bad pack compression level %d", pack_compression_level);
2452#ifdef NO_PTHREADS
2453        if (delta_search_threads != 1)
2454                warning("no threads support, ignoring --threads");
2455#endif
2456        if (!pack_to_stdout && !pack_size_limit)
2457                pack_size_limit = pack_size_limit_cfg;
2458        if (pack_to_stdout && pack_size_limit)
2459                die("--max-pack-size cannot be used to build a pack for transfer.");
2460        if (pack_size_limit && pack_size_limit < 1024*1024) {
2461                warning("minimum pack size limit is 1 MiB");
2462                pack_size_limit = 1024*1024;
2463        }
2464
2465        if (!pack_to_stdout && thin)
2466                die("--thin cannot be used to build an indexable pack.");
2467
2468        if (keep_unreachable && unpack_unreachable)
2469                die("--keep-unreachable and --unpack-unreachable are incompatible.");
2470
2471        if (progress && all_progress_implied)
2472                progress = 2;
2473
2474        prepare_packed_git();
2475
2476        if (progress)
2477                progress_state = start_progress("Counting objects", 0);
2478        if (!use_internal_rev_list)
2479                read_object_list_from_stdin();
2480        else {
2481                rp_av[rp_ac] = NULL;
2482                get_object_list(rp_ac, rp_av);
2483        }
2484        cleanup_preferred_base();
2485        if (include_tag && nr_result)
2486                for_each_ref(add_ref_tag, NULL);
2487        stop_progress(&progress_state);
2488
2489        if (non_empty && !nr_result)
2490                return 0;
2491        if (nr_result)
2492                prepare_pack(window, depth);
2493        write_pack_file();
2494        if (progress)
2495                fprintf(stderr, "Total %"PRIu32" (delta %"PRIu32"),"
2496                        " reused %"PRIu32" (delta %"PRIu32")\n",
2497                        written, written_delta, reused, reused_delta);
2498        return 0;
2499}