builtin / index-pack.con commit Merge branch 'sp/maint-upload-pack-stop-early' (f59bf09)
   1#include "cache.h"
   2#include "delta.h"
   3#include "pack.h"
   4#include "csum-file.h"
   5#include "blob.h"
   6#include "commit.h"
   7#include "tag.h"
   8#include "tree.h"
   9#include "progress.h"
  10#include "fsck.h"
  11#include "exec_cmd.h"
  12
  13static const char index_pack_usage[] =
  14"git index-pack [-v] [-o <index-file>] [ --keep | --keep=<msg> ] [--strict] (<pack-file> | --stdin [--fix-thin] [<pack-file>])";
  15
  16struct object_entry {
  17        struct pack_idx_entry idx;
  18        unsigned long size;
  19        unsigned int hdr_size;
  20        enum object_type type;
  21        enum object_type real_type;
  22};
  23
  24union delta_base {
  25        unsigned char sha1[20];
  26        off_t offset;
  27};
  28
  29struct base_data {
  30        struct base_data *base;
  31        struct base_data *child;
  32        struct object_entry *obj;
  33        void *data;
  34        unsigned long size;
  35};
  36
  37/*
  38 * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  39 * to memcmp() only the first 20 bytes.
  40 */
  41#define UNION_BASE_SZ   20
  42
  43#define FLAG_LINK (1u<<20)
  44#define FLAG_CHECKED (1u<<21)
  45
  46struct delta_entry {
  47        union delta_base base;
  48        int obj_no;
  49};
  50
  51static struct object_entry *objects;
  52static struct delta_entry *deltas;
  53static struct base_data *base_cache;
  54static size_t base_cache_used;
  55static int nr_objects;
  56static int nr_deltas;
  57static int nr_resolved_deltas;
  58
  59static int from_stdin;
  60static int strict;
  61static int verbose;
  62
  63static struct progress *progress;
  64
  65/* We always read in 4kB chunks. */
  66static unsigned char input_buffer[4096];
  67static unsigned int input_offset, input_len;
  68static off_t consumed_bytes;
  69static git_SHA_CTX input_ctx;
  70static uint32_t input_crc32;
  71static int input_fd, output_fd, pack_fd;
  72
  73static int mark_link(struct object *obj, int type, void *data)
  74{
  75        if (!obj)
  76                return -1;
  77
  78        if (type != OBJ_ANY && obj->type != type)
  79                die("object type mismatch at %s", sha1_to_hex(obj->sha1));
  80
  81        obj->flags |= FLAG_LINK;
  82        return 0;
  83}
  84
  85/* The content of each linked object must have been checked
  86   or it must be already present in the object database */
  87static void check_object(struct object *obj)
  88{
  89        if (!obj)
  90                return;
  91
  92        if (!(obj->flags & FLAG_LINK))
  93                return;
  94
  95        if (!(obj->flags & FLAG_CHECKED)) {
  96                unsigned long size;
  97                int type = sha1_object_info(obj->sha1, &size);
  98                if (type != obj->type || type <= 0)
  99                        die("object of unexpected type");
 100                obj->flags |= FLAG_CHECKED;
 101                return;
 102        }
 103}
 104
 105static void check_objects(void)
 106{
 107        unsigned i, max;
 108
 109        max = get_max_object_index();
 110        for (i = 0; i < max; i++)
 111                check_object(get_indexed_object(i));
 112}
 113
 114
 115/* Discard current buffer used content. */
 116static void flush(void)
 117{
 118        if (input_offset) {
 119                if (output_fd >= 0)
 120                        write_or_die(output_fd, input_buffer, input_offset);
 121                git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 122                memmove(input_buffer, input_buffer + input_offset, input_len);
 123                input_offset = 0;
 124        }
 125}
 126
 127/*
 128 * Make sure at least "min" bytes are available in the buffer, and
 129 * return the pointer to the buffer.
 130 */
 131static void *fill(int min)
 132{
 133        if (min <= input_len)
 134                return input_buffer + input_offset;
 135        if (min > sizeof(input_buffer))
 136                die("cannot fill %d bytes", min);
 137        flush();
 138        do {
 139                ssize_t ret = xread(input_fd, input_buffer + input_len,
 140                                sizeof(input_buffer) - input_len);
 141                if (ret <= 0) {
 142                        if (!ret)
 143                                die("early EOF");
 144                        die_errno("read error on input");
 145                }
 146                input_len += ret;
 147                if (from_stdin)
 148                        display_throughput(progress, consumed_bytes + input_len);
 149        } while (input_len < min);
 150        return input_buffer;
 151}
 152
 153static void use(int bytes)
 154{
 155        if (bytes > input_len)
 156                die("used more bytes than were available");
 157        input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 158        input_len -= bytes;
 159        input_offset += bytes;
 160
 161        /* make sure off_t is sufficiently large not to wrap */
 162        if (signed_add_overflows(consumed_bytes, bytes))
 163                die("pack too large for current definition of off_t");
 164        consumed_bytes += bytes;
 165}
 166
 167static const char *open_pack_file(const char *pack_name)
 168{
 169        if (from_stdin) {
 170                input_fd = 0;
 171                if (!pack_name) {
 172                        static char tmpfile[PATH_MAX];
 173                        output_fd = odb_mkstemp(tmpfile, sizeof(tmpfile),
 174                                                "pack/tmp_pack_XXXXXX");
 175                        pack_name = xstrdup(tmpfile);
 176                } else
 177                        output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 178                if (output_fd < 0)
 179                        die_errno("unable to create '%s'", pack_name);
 180                pack_fd = output_fd;
 181        } else {
 182                input_fd = open(pack_name, O_RDONLY);
 183                if (input_fd < 0)
 184                        die_errno("cannot open packfile '%s'", pack_name);
 185                output_fd = -1;
 186                pack_fd = input_fd;
 187        }
 188        git_SHA1_Init(&input_ctx);
 189        return pack_name;
 190}
 191
 192static void parse_pack_header(void)
 193{
 194        struct pack_header *hdr = fill(sizeof(struct pack_header));
 195
 196        /* Header consistency check */
 197        if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 198                die("pack signature mismatch");
 199        if (!pack_version_ok(hdr->hdr_version))
 200                die("pack version %"PRIu32" unsupported",
 201                        ntohl(hdr->hdr_version));
 202
 203        nr_objects = ntohl(hdr->hdr_entries);
 204        use(sizeof(struct pack_header));
 205}
 206
 207static NORETURN void bad_object(unsigned long offset, const char *format,
 208                       ...) __attribute__((format (printf, 2, 3)));
 209
 210static NORETURN void bad_object(unsigned long offset, const char *format, ...)
 211{
 212        va_list params;
 213        char buf[1024];
 214
 215        va_start(params, format);
 216        vsnprintf(buf, sizeof(buf), format, params);
 217        va_end(params);
 218        die("pack has bad object at offset %lu: %s", offset, buf);
 219}
 220
 221static void free_base_data(struct base_data *c)
 222{
 223        if (c->data) {
 224                free(c->data);
 225                c->data = NULL;
 226                base_cache_used -= c->size;
 227        }
 228}
 229
 230static void prune_base_data(struct base_data *retain)
 231{
 232        struct base_data *b;
 233        for (b = base_cache;
 234             base_cache_used > delta_base_cache_limit && b;
 235             b = b->child) {
 236                if (b->data && b != retain)
 237                        free_base_data(b);
 238        }
 239}
 240
 241static void link_base_data(struct base_data *base, struct base_data *c)
 242{
 243        if (base)
 244                base->child = c;
 245        else
 246                base_cache = c;
 247
 248        c->base = base;
 249        c->child = NULL;
 250        if (c->data)
 251                base_cache_used += c->size;
 252        prune_base_data(c);
 253}
 254
 255static void unlink_base_data(struct base_data *c)
 256{
 257        struct base_data *base = c->base;
 258        if (base)
 259                base->child = NULL;
 260        else
 261                base_cache = NULL;
 262        free_base_data(c);
 263}
 264
 265static void *unpack_entry_data(unsigned long offset, unsigned long size)
 266{
 267        int status;
 268        z_stream stream;
 269        void *buf = xmalloc(size);
 270
 271        memset(&stream, 0, sizeof(stream));
 272        git_inflate_init(&stream);
 273        stream.next_out = buf;
 274        stream.avail_out = size;
 275
 276        do {
 277                stream.next_in = fill(1);
 278                stream.avail_in = input_len;
 279                status = git_inflate(&stream, 0);
 280                use(input_len - stream.avail_in);
 281        } while (status == Z_OK);
 282        if (stream.total_out != size || status != Z_STREAM_END)
 283                bad_object(offset, "inflate returned %d", status);
 284        git_inflate_end(&stream);
 285        return buf;
 286}
 287
 288static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 289{
 290        unsigned char *p;
 291        unsigned long size, c;
 292        off_t base_offset;
 293        unsigned shift;
 294        void *data;
 295
 296        obj->idx.offset = consumed_bytes;
 297        input_crc32 = crc32(0, Z_NULL, 0);
 298
 299        p = fill(1);
 300        c = *p;
 301        use(1);
 302        obj->type = (c >> 4) & 7;
 303        size = (c & 15);
 304        shift = 4;
 305        while (c & 0x80) {
 306                p = fill(1);
 307                c = *p;
 308                use(1);
 309                size += (c & 0x7f) << shift;
 310                shift += 7;
 311        }
 312        obj->size = size;
 313
 314        switch (obj->type) {
 315        case OBJ_REF_DELTA:
 316                hashcpy(delta_base->sha1, fill(20));
 317                use(20);
 318                break;
 319        case OBJ_OFS_DELTA:
 320                memset(delta_base, 0, sizeof(*delta_base));
 321                p = fill(1);
 322                c = *p;
 323                use(1);
 324                base_offset = c & 127;
 325                while (c & 128) {
 326                        base_offset += 1;
 327                        if (!base_offset || MSB(base_offset, 7))
 328                                bad_object(obj->idx.offset, "offset value overflow for delta base object");
 329                        p = fill(1);
 330                        c = *p;
 331                        use(1);
 332                        base_offset = (base_offset << 7) + (c & 127);
 333                }
 334                delta_base->offset = obj->idx.offset - base_offset;
 335                if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
 336                        bad_object(obj->idx.offset, "delta base offset is out of bound");
 337                break;
 338        case OBJ_COMMIT:
 339        case OBJ_TREE:
 340        case OBJ_BLOB:
 341        case OBJ_TAG:
 342                break;
 343        default:
 344                bad_object(obj->idx.offset, "unknown object type %d", obj->type);
 345        }
 346        obj->hdr_size = consumed_bytes - obj->idx.offset;
 347
 348        data = unpack_entry_data(obj->idx.offset, obj->size);
 349        obj->idx.crc32 = input_crc32;
 350        return data;
 351}
 352
 353static void *get_data_from_pack(struct object_entry *obj)
 354{
 355        off_t from = obj[0].idx.offset + obj[0].hdr_size;
 356        unsigned long len = obj[1].idx.offset - from;
 357        unsigned char *data, *inbuf;
 358        z_stream stream;
 359        int status;
 360
 361        data = xmalloc(obj->size);
 362        inbuf = xmalloc((len < 64*1024) ? len : 64*1024);
 363
 364        memset(&stream, 0, sizeof(stream));
 365        git_inflate_init(&stream);
 366        stream.next_out = data;
 367        stream.avail_out = obj->size;
 368
 369        do {
 370                ssize_t n = (len < 64*1024) ? len : 64*1024;
 371                n = pread(pack_fd, inbuf, n, from);
 372                if (n < 0)
 373                        die_errno("cannot pread pack file");
 374                if (!n)
 375                        die("premature end of pack file, %lu bytes missing", len);
 376                from += n;
 377                len -= n;
 378                stream.next_in = inbuf;
 379                stream.avail_in = n;
 380                status = git_inflate(&stream, 0);
 381        } while (len && status == Z_OK && !stream.avail_in);
 382
 383        /* This has been inflated OK when first encountered, so... */
 384        if (status != Z_STREAM_END || stream.total_out != obj->size)
 385                die("serious inflate inconsistency");
 386
 387        git_inflate_end(&stream);
 388        free(inbuf);
 389        return data;
 390}
 391
 392static int find_delta(const union delta_base *base)
 393{
 394        int first = 0, last = nr_deltas;
 395
 396        while (first < last) {
 397                int next = (first + last) / 2;
 398                struct delta_entry *delta = &deltas[next];
 399                int cmp;
 400
 401                cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
 402                if (!cmp)
 403                        return next;
 404                if (cmp < 0) {
 405                        last = next;
 406                        continue;
 407                }
 408                first = next+1;
 409        }
 410        return -first-1;
 411}
 412
 413static void find_delta_children(const union delta_base *base,
 414                                int *first_index, int *last_index)
 415{
 416        int first = find_delta(base);
 417        int last = first;
 418        int end = nr_deltas - 1;
 419
 420        if (first < 0) {
 421                *first_index = 0;
 422                *last_index = -1;
 423                return;
 424        }
 425        while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 426                --first;
 427        while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 428                ++last;
 429        *first_index = first;
 430        *last_index = last;
 431}
 432
 433static void sha1_object(const void *data, unsigned long size,
 434                        enum object_type type, unsigned char *sha1)
 435{
 436        hash_sha1_file(data, size, typename(type), sha1);
 437        if (has_sha1_file(sha1)) {
 438                void *has_data;
 439                enum object_type has_type;
 440                unsigned long has_size;
 441                has_data = read_sha1_file(sha1, &has_type, &has_size);
 442                if (!has_data)
 443                        die("cannot read existing object %s", sha1_to_hex(sha1));
 444                if (size != has_size || type != has_type ||
 445                    memcmp(data, has_data, size) != 0)
 446                        die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
 447                free(has_data);
 448        }
 449        if (strict) {
 450                if (type == OBJ_BLOB) {
 451                        struct blob *blob = lookup_blob(sha1);
 452                        if (blob)
 453                                blob->object.flags |= FLAG_CHECKED;
 454                        else
 455                                die("invalid blob object %s", sha1_to_hex(sha1));
 456                } else {
 457                        struct object *obj;
 458                        int eaten;
 459                        void *buf = (void *) data;
 460
 461                        /*
 462                         * we do not need to free the memory here, as the
 463                         * buf is deleted by the caller.
 464                         */
 465                        obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 466                        if (!obj)
 467                                die("invalid %s", typename(type));
 468                        if (fsck_object(obj, 1, fsck_error_function))
 469                                die("Error in object");
 470                        if (fsck_walk(obj, mark_link, NULL))
 471                                die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
 472
 473                        if (obj->type == OBJ_TREE) {
 474                                struct tree *item = (struct tree *) obj;
 475                                item->buffer = NULL;
 476                        }
 477                        if (obj->type == OBJ_COMMIT) {
 478                                struct commit *commit = (struct commit *) obj;
 479                                commit->buffer = NULL;
 480                        }
 481                        obj->flags |= FLAG_CHECKED;
 482                }
 483        }
 484}
 485
 486static void *get_base_data(struct base_data *c)
 487{
 488        if (!c->data) {
 489                struct object_entry *obj = c->obj;
 490
 491                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 492                        void *base = get_base_data(c->base);
 493                        void *raw = get_data_from_pack(obj);
 494                        c->data = patch_delta(
 495                                base, c->base->size,
 496                                raw, obj->size,
 497                                &c->size);
 498                        free(raw);
 499                        if (!c->data)
 500                                bad_object(obj->idx.offset, "failed to apply delta");
 501                } else {
 502                        c->data = get_data_from_pack(obj);
 503                        c->size = obj->size;
 504                }
 505
 506                base_cache_used += c->size;
 507                prune_base_data(c);
 508        }
 509        return c->data;
 510}
 511
 512static void resolve_delta(struct object_entry *delta_obj,
 513                          struct base_data *base, struct base_data *result)
 514{
 515        void *base_data, *delta_data;
 516
 517        delta_obj->real_type = base->obj->real_type;
 518        delta_data = get_data_from_pack(delta_obj);
 519        base_data = get_base_data(base);
 520        result->obj = delta_obj;
 521        result->data = patch_delta(base_data, base->size,
 522                                   delta_data, delta_obj->size, &result->size);
 523        free(delta_data);
 524        if (!result->data)
 525                bad_object(delta_obj->idx.offset, "failed to apply delta");
 526        sha1_object(result->data, result->size, delta_obj->real_type,
 527                    delta_obj->idx.sha1);
 528        nr_resolved_deltas++;
 529}
 530
 531static void find_unresolved_deltas(struct base_data *base,
 532                                   struct base_data *prev_base)
 533{
 534        int i, ref_first, ref_last, ofs_first, ofs_last;
 535
 536        /*
 537         * This is a recursive function. Those brackets should help reducing
 538         * stack usage by limiting the scope of the delta_base union.
 539         */
 540        {
 541                union delta_base base_spec;
 542
 543                hashcpy(base_spec.sha1, base->obj->idx.sha1);
 544                find_delta_children(&base_spec, &ref_first, &ref_last);
 545
 546                memset(&base_spec, 0, sizeof(base_spec));
 547                base_spec.offset = base->obj->idx.offset;
 548                find_delta_children(&base_spec, &ofs_first, &ofs_last);
 549        }
 550
 551        if (ref_last == -1 && ofs_last == -1) {
 552                free(base->data);
 553                return;
 554        }
 555
 556        link_base_data(prev_base, base);
 557
 558        for (i = ref_first; i <= ref_last; i++) {
 559                struct object_entry *child = objects + deltas[i].obj_no;
 560                if (child->real_type == OBJ_REF_DELTA) {
 561                        struct base_data result;
 562                        resolve_delta(child, base, &result);
 563                        if (i == ref_last && ofs_last == -1)
 564                                free_base_data(base);
 565                        find_unresolved_deltas(&result, base);
 566                }
 567        }
 568
 569        for (i = ofs_first; i <= ofs_last; i++) {
 570                struct object_entry *child = objects + deltas[i].obj_no;
 571                if (child->real_type == OBJ_OFS_DELTA) {
 572                        struct base_data result;
 573                        resolve_delta(child, base, &result);
 574                        if (i == ofs_last)
 575                                free_base_data(base);
 576                        find_unresolved_deltas(&result, base);
 577                }
 578        }
 579
 580        unlink_base_data(base);
 581}
 582
 583static int compare_delta_entry(const void *a, const void *b)
 584{
 585        const struct delta_entry *delta_a = a;
 586        const struct delta_entry *delta_b = b;
 587        return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
 588}
 589
 590/* Parse all objects and return the pack content SHA1 hash */
 591static void parse_pack_objects(unsigned char *sha1)
 592{
 593        int i;
 594        struct delta_entry *delta = deltas;
 595        struct stat st;
 596
 597        /*
 598         * First pass:
 599         * - find locations of all objects;
 600         * - calculate SHA1 of all non-delta objects;
 601         * - remember base (SHA1 or offset) for all deltas.
 602         */
 603        if (verbose)
 604                progress = start_progress(
 605                                from_stdin ? "Receiving objects" : "Indexing objects",
 606                                nr_objects);
 607        for (i = 0; i < nr_objects; i++) {
 608                struct object_entry *obj = &objects[i];
 609                void *data = unpack_raw_entry(obj, &delta->base);
 610                obj->real_type = obj->type;
 611                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 612                        nr_deltas++;
 613                        delta->obj_no = i;
 614                        delta++;
 615                } else
 616                        sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 617                free(data);
 618                display_progress(progress, i+1);
 619        }
 620        objects[i].idx.offset = consumed_bytes;
 621        stop_progress(&progress);
 622
 623        /* Check pack integrity */
 624        flush();
 625        git_SHA1_Final(sha1, &input_ctx);
 626        if (hashcmp(fill(20), sha1))
 627                die("pack is corrupted (SHA1 mismatch)");
 628        use(20);
 629
 630        /* If input_fd is a file, we should have reached its end now. */
 631        if (fstat(input_fd, &st))
 632                die_errno("cannot fstat packfile");
 633        if (S_ISREG(st.st_mode) &&
 634                        lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 635                die("pack has junk at the end");
 636
 637        if (!nr_deltas)
 638                return;
 639
 640        /* Sort deltas by base SHA1/offset for fast searching */
 641        qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 642              compare_delta_entry);
 643
 644        /*
 645         * Second pass:
 646         * - for all non-delta objects, look if it is used as a base for
 647         *   deltas;
 648         * - if used as a base, uncompress the object and apply all deltas,
 649         *   recursively checking if the resulting object is used as a base
 650         *   for some more deltas.
 651         */
 652        if (verbose)
 653                progress = start_progress("Resolving deltas", nr_deltas);
 654        for (i = 0; i < nr_objects; i++) {
 655                struct object_entry *obj = &objects[i];
 656                struct base_data base_obj;
 657
 658                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
 659                        continue;
 660                base_obj.obj = obj;
 661                base_obj.data = NULL;
 662                find_unresolved_deltas(&base_obj, NULL);
 663                display_progress(progress, nr_resolved_deltas);
 664        }
 665}
 666
 667static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 668{
 669        z_stream stream;
 670        int status;
 671        unsigned char outbuf[4096];
 672
 673        memset(&stream, 0, sizeof(stream));
 674        deflateInit(&stream, zlib_compression_level);
 675        stream.next_in = in;
 676        stream.avail_in = size;
 677
 678        do {
 679                stream.next_out = outbuf;
 680                stream.avail_out = sizeof(outbuf);
 681                status = deflate(&stream, Z_FINISH);
 682                sha1write(f, outbuf, sizeof(outbuf) - stream.avail_out);
 683        } while (status == Z_OK);
 684
 685        if (status != Z_STREAM_END)
 686                die("unable to deflate appended object (%d)", status);
 687        size = stream.total_out;
 688        deflateEnd(&stream);
 689        return size;
 690}
 691
 692static struct object_entry *append_obj_to_pack(struct sha1file *f,
 693                               const unsigned char *sha1, void *buf,
 694                               unsigned long size, enum object_type type)
 695{
 696        struct object_entry *obj = &objects[nr_objects++];
 697        unsigned char header[10];
 698        unsigned long s = size;
 699        int n = 0;
 700        unsigned char c = (type << 4) | (s & 15);
 701        s >>= 4;
 702        while (s) {
 703                header[n++] = c | 0x80;
 704                c = s & 0x7f;
 705                s >>= 7;
 706        }
 707        header[n++] = c;
 708        crc32_begin(f);
 709        sha1write(f, header, n);
 710        obj[0].size = size;
 711        obj[0].hdr_size = n;
 712        obj[0].type = type;
 713        obj[0].real_type = type;
 714        obj[1].idx.offset = obj[0].idx.offset + n;
 715        obj[1].idx.offset += write_compressed(f, buf, size);
 716        obj[0].idx.crc32 = crc32_end(f);
 717        sha1flush(f);
 718        hashcpy(obj->idx.sha1, sha1);
 719        return obj;
 720}
 721
 722static int delta_pos_compare(const void *_a, const void *_b)
 723{
 724        struct delta_entry *a = *(struct delta_entry **)_a;
 725        struct delta_entry *b = *(struct delta_entry **)_b;
 726        return a->obj_no - b->obj_no;
 727}
 728
 729static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
 730{
 731        struct delta_entry **sorted_by_pos;
 732        int i, n = 0;
 733
 734        /*
 735         * Since many unresolved deltas may well be themselves base objects
 736         * for more unresolved deltas, we really want to include the
 737         * smallest number of base objects that would cover as much delta
 738         * as possible by picking the
 739         * trunc deltas first, allowing for other deltas to resolve without
 740         * additional base objects.  Since most base objects are to be found
 741         * before deltas depending on them, a good heuristic is to start
 742         * resolving deltas in the same order as their position in the pack.
 743         */
 744        sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 745        for (i = 0; i < nr_deltas; i++) {
 746                if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 747                        continue;
 748                sorted_by_pos[n++] = &deltas[i];
 749        }
 750        qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 751
 752        for (i = 0; i < n; i++) {
 753                struct delta_entry *d = sorted_by_pos[i];
 754                enum object_type type;
 755                struct base_data base_obj;
 756
 757                if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 758                        continue;
 759                base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
 760                if (!base_obj.data)
 761                        continue;
 762
 763                if (check_sha1_signature(d->base.sha1, base_obj.data,
 764                                base_obj.size, typename(type)))
 765                        die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
 766                base_obj.obj = append_obj_to_pack(f, d->base.sha1,
 767                                        base_obj.data, base_obj.size, type);
 768                find_unresolved_deltas(&base_obj, NULL);
 769                display_progress(progress, nr_resolved_deltas);
 770        }
 771        free(sorted_by_pos);
 772}
 773
 774static void final(const char *final_pack_name, const char *curr_pack_name,
 775                  const char *final_index_name, const char *curr_index_name,
 776                  const char *keep_name, const char *keep_msg,
 777                  unsigned char *sha1)
 778{
 779        const char *report = "pack";
 780        char name[PATH_MAX];
 781        int err;
 782
 783        if (!from_stdin) {
 784                close(input_fd);
 785        } else {
 786                fsync_or_die(output_fd, curr_pack_name);
 787                err = close(output_fd);
 788                if (err)
 789                        die_errno("error while closing pack file");
 790        }
 791
 792        if (keep_msg) {
 793                int keep_fd, keep_msg_len = strlen(keep_msg);
 794
 795                if (!keep_name)
 796                        keep_fd = odb_pack_keep(name, sizeof(name), sha1);
 797                else
 798                        keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 799
 800                if (keep_fd < 0) {
 801                        if (errno != EEXIST)
 802                                die_errno("cannot write keep file '%s'",
 803                                          keep_name);
 804                } else {
 805                        if (keep_msg_len > 0) {
 806                                write_or_die(keep_fd, keep_msg, keep_msg_len);
 807                                write_or_die(keep_fd, "\n", 1);
 808                        }
 809                        if (close(keep_fd) != 0)
 810                                die_errno("cannot close written keep file '%s'",
 811                                    keep_name);
 812                        report = "keep";
 813                }
 814        }
 815
 816        if (final_pack_name != curr_pack_name) {
 817                if (!final_pack_name) {
 818                        snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 819                                 get_object_directory(), sha1_to_hex(sha1));
 820                        final_pack_name = name;
 821                }
 822                if (move_temp_to_file(curr_pack_name, final_pack_name))
 823                        die("cannot store pack file");
 824        } else if (from_stdin)
 825                chmod(final_pack_name, 0444);
 826
 827        if (final_index_name != curr_index_name) {
 828                if (!final_index_name) {
 829                        snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 830                                 get_object_directory(), sha1_to_hex(sha1));
 831                        final_index_name = name;
 832                }
 833                if (move_temp_to_file(curr_index_name, final_index_name))
 834                        die("cannot store index file");
 835        } else
 836                chmod(final_index_name, 0444);
 837
 838        if (!from_stdin) {
 839                printf("%s\n", sha1_to_hex(sha1));
 840        } else {
 841                char buf[48];
 842                int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 843                                   report, sha1_to_hex(sha1));
 844                write_or_die(1, buf, len);
 845
 846                /*
 847                 * Let's just mimic git-unpack-objects here and write
 848                 * the last part of the input buffer to stdout.
 849                 */
 850                while (input_len) {
 851                        err = xwrite(1, input_buffer + input_offset, input_len);
 852                        if (err <= 0)
 853                                break;
 854                        input_len -= err;
 855                        input_offset += err;
 856                }
 857        }
 858}
 859
 860static int git_index_pack_config(const char *k, const char *v, void *cb)
 861{
 862        if (!strcmp(k, "pack.indexversion")) {
 863                pack_idx_default_version = git_config_int(k, v);
 864                if (pack_idx_default_version > 2)
 865                        die("bad pack.indexversion=%"PRIu32,
 866                                pack_idx_default_version);
 867                return 0;
 868        }
 869        return git_default_config(k, v, cb);
 870}
 871
 872int cmd_index_pack(int argc, const char **argv, const char *prefix)
 873{
 874        int i, fix_thin_pack = 0;
 875        const char *curr_pack, *curr_index;
 876        const char *index_name = NULL, *pack_name = NULL;
 877        const char *keep_name = NULL, *keep_msg = NULL;
 878        char *index_name_buf = NULL, *keep_name_buf = NULL;
 879        struct pack_idx_entry **idx_objects;
 880        unsigned char pack_sha1[20];
 881
 882        if (argc == 2 && !strcmp(argv[1], "-h"))
 883                usage(index_pack_usage);
 884
 885        read_replace_refs = 0;
 886
 887        git_config(git_index_pack_config, NULL);
 888        if (prefix && chdir(prefix))
 889                die("Cannot come back to cwd");
 890
 891        for (i = 1; i < argc; i++) {
 892                const char *arg = argv[i];
 893
 894                if (*arg == '-') {
 895                        if (!strcmp(arg, "--stdin")) {
 896                                from_stdin = 1;
 897                        } else if (!strcmp(arg, "--fix-thin")) {
 898                                fix_thin_pack = 1;
 899                        } else if (!strcmp(arg, "--strict")) {
 900                                strict = 1;
 901                        } else if (!strcmp(arg, "--keep")) {
 902                                keep_msg = "";
 903                        } else if (!prefixcmp(arg, "--keep=")) {
 904                                keep_msg = arg + 7;
 905                        } else if (!prefixcmp(arg, "--pack_header=")) {
 906                                struct pack_header *hdr;
 907                                char *c;
 908
 909                                hdr = (struct pack_header *)input_buffer;
 910                                hdr->hdr_signature = htonl(PACK_SIGNATURE);
 911                                hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 912                                if (*c != ',')
 913                                        die("bad %s", arg);
 914                                hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 915                                if (*c)
 916                                        die("bad %s", arg);
 917                                input_len = sizeof(*hdr);
 918                        } else if (!strcmp(arg, "-v")) {
 919                                verbose = 1;
 920                        } else if (!strcmp(arg, "-o")) {
 921                                if (index_name || (i+1) >= argc)
 922                                        usage(index_pack_usage);
 923                                index_name = argv[++i];
 924                        } else if (!prefixcmp(arg, "--index-version=")) {
 925                                char *c;
 926                                pack_idx_default_version = strtoul(arg + 16, &c, 10);
 927                                if (pack_idx_default_version > 2)
 928                                        die("bad %s", arg);
 929                                if (*c == ',')
 930                                        pack_idx_off32_limit = strtoul(c+1, &c, 0);
 931                                if (*c || pack_idx_off32_limit & 0x80000000)
 932                                        die("bad %s", arg);
 933                        } else
 934                                usage(index_pack_usage);
 935                        continue;
 936                }
 937
 938                if (pack_name)
 939                        usage(index_pack_usage);
 940                pack_name = arg;
 941        }
 942
 943        if (!pack_name && !from_stdin)
 944                usage(index_pack_usage);
 945        if (fix_thin_pack && !from_stdin)
 946                die("--fix-thin cannot be used without --stdin");
 947        if (!index_name && pack_name) {
 948                int len = strlen(pack_name);
 949                if (!has_extension(pack_name, ".pack"))
 950                        die("packfile name '%s' does not end with '.pack'",
 951                            pack_name);
 952                index_name_buf = xmalloc(len);
 953                memcpy(index_name_buf, pack_name, len - 5);
 954                strcpy(index_name_buf + len - 5, ".idx");
 955                index_name = index_name_buf;
 956        }
 957        if (keep_msg && !keep_name && pack_name) {
 958                int len = strlen(pack_name);
 959                if (!has_extension(pack_name, ".pack"))
 960                        die("packfile name '%s' does not end with '.pack'",
 961                            pack_name);
 962                keep_name_buf = xmalloc(len);
 963                memcpy(keep_name_buf, pack_name, len - 5);
 964                strcpy(keep_name_buf + len - 5, ".keep");
 965                keep_name = keep_name_buf;
 966        }
 967
 968        curr_pack = open_pack_file(pack_name);
 969        parse_pack_header();
 970        objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
 971        deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
 972        parse_pack_objects(pack_sha1);
 973        if (nr_deltas == nr_resolved_deltas) {
 974                stop_progress(&progress);
 975                /* Flush remaining pack final 20-byte SHA1. */
 976                flush();
 977        } else {
 978                if (fix_thin_pack) {
 979                        struct sha1file *f;
 980                        unsigned char read_sha1[20], tail_sha1[20];
 981                        char msg[48];
 982                        int nr_unresolved = nr_deltas - nr_resolved_deltas;
 983                        int nr_objects_initial = nr_objects;
 984                        if (nr_unresolved <= 0)
 985                                die("confusion beyond insanity");
 986                        objects = xrealloc(objects,
 987                                           (nr_objects + nr_unresolved + 1)
 988                                           * sizeof(*objects));
 989                        f = sha1fd(output_fd, curr_pack);
 990                        fix_unresolved_deltas(f, nr_unresolved);
 991                        sprintf(msg, "completed with %d local objects",
 992                                nr_objects - nr_objects_initial);
 993                        stop_progress_msg(&progress, msg);
 994                        sha1close(f, tail_sha1, 0);
 995                        hashcpy(read_sha1, pack_sha1);
 996                        fixup_pack_header_footer(output_fd, pack_sha1,
 997                                                 curr_pack, nr_objects,
 998                                                 read_sha1, consumed_bytes-20);
 999                        if (hashcmp(read_sha1, tail_sha1) != 0)
1000                                die("Unexpected tail checksum for %s "
1001                                    "(disk corruption?)", curr_pack);
1002                }
1003                if (nr_deltas != nr_resolved_deltas)
1004                        die("pack has %d unresolved deltas",
1005                            nr_deltas - nr_resolved_deltas);
1006        }
1007        free(deltas);
1008        if (strict)
1009                check_objects();
1010
1011        idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1012        for (i = 0; i < nr_objects; i++)
1013                idx_objects[i] = &objects[i].idx;
1014        curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
1015        free(idx_objects);
1016
1017        final(pack_name, curr_pack,
1018                index_name, curr_index,
1019                keep_name, keep_msg,
1020                pack_sha1);
1021        free(objects);
1022        free(index_name_buf);
1023        free(keep_name_buf);
1024        if (pack_name == NULL)
1025                free((void *) curr_pack);
1026        if (index_name == NULL)
1027                free((void *) curr_index);
1028
1029        return 0;
1030}