builtin / index-pack.con commit Merge branch 'bg/apply-fix-blank-at-eof' (31fbae0)
   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{
  18        struct pack_idx_entry idx;
  19        unsigned long size;
  20        unsigned int hdr_size;
  21        enum object_type type;
  22        enum object_type real_type;
  23};
  24
  25union delta_base {
  26        unsigned char sha1[20];
  27        off_t offset;
  28};
  29
  30struct base_data {
  31        struct base_data *base;
  32        struct base_data *child;
  33        struct object_entry *obj;
  34        void *data;
  35        unsigned long size;
  36};
  37
  38/*
  39 * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  40 * to memcmp() only the first 20 bytes.
  41 */
  42#define UNION_BASE_SZ   20
  43
  44#define FLAG_LINK (1u<<20)
  45#define FLAG_CHECKED (1u<<21)
  46
  47struct delta_entry
  48{
  49        union delta_base base;
  50        int obj_no;
  51};
  52
  53static struct object_entry *objects;
  54static struct delta_entry *deltas;
  55static struct base_data *base_cache;
  56static size_t base_cache_used;
  57static int nr_objects;
  58static int nr_deltas;
  59static int nr_resolved_deltas;
  60
  61static int from_stdin;
  62static int strict;
  63static int verbose;
  64
  65static struct progress *progress;
  66
  67/* We always read in 4kB chunks. */
  68static unsigned char input_buffer[4096];
  69static unsigned int input_offset, input_len;
  70static off_t consumed_bytes;
  71static git_SHA_CTX input_ctx;
  72static uint32_t input_crc32;
  73static int input_fd, output_fd, pack_fd;
  74
  75static int mark_link(struct object *obj, int type, void *data)
  76{
  77        if (!obj)
  78                return -1;
  79
  80        if (type != OBJ_ANY && obj->type != type)
  81                die("object type mismatch at %s", sha1_to_hex(obj->sha1));
  82
  83        obj->flags |= FLAG_LINK;
  84        return 0;
  85}
  86
  87/* The content of each linked object must have been checked
  88   or it must be already present in the object database */
  89static void check_object(struct object *obj)
  90{
  91        if (!obj)
  92                return;
  93
  94        if (!(obj->flags & FLAG_LINK))
  95                return;
  96
  97        if (!(obj->flags & FLAG_CHECKED)) {
  98                unsigned long size;
  99                int type = sha1_object_info(obj->sha1, &size);
 100                if (type != obj->type || type <= 0)
 101                        die("object of unexpected type");
 102                obj->flags |= FLAG_CHECKED;
 103                return;
 104        }
 105}
 106
 107static void check_objects(void)
 108{
 109        unsigned i, max;
 110
 111        max = get_max_object_index();
 112        for (i = 0; i < max; i++)
 113                check_object(get_indexed_object(i));
 114}
 115
 116
 117/* Discard current buffer used content. */
 118static void flush(void)
 119{
 120        if (input_offset) {
 121                if (output_fd >= 0)
 122                        write_or_die(output_fd, input_buffer, input_offset);
 123                git_SHA1_Update(&input_ctx, input_buffer, input_offset);
 124                memmove(input_buffer, input_buffer + input_offset, input_len);
 125                input_offset = 0;
 126        }
 127}
 128
 129/*
 130 * Make sure at least "min" bytes are available in the buffer, and
 131 * return the pointer to the buffer.
 132 */
 133static void *fill(int min)
 134{
 135        if (min <= input_len)
 136                return input_buffer + input_offset;
 137        if (min > sizeof(input_buffer))
 138                die("cannot fill %d bytes", min);
 139        flush();
 140        do {
 141                ssize_t ret = xread(input_fd, input_buffer + input_len,
 142                                sizeof(input_buffer) - input_len);
 143                if (ret <= 0) {
 144                        if (!ret)
 145                                die("early EOF");
 146                        die_errno("read error on input");
 147                }
 148                input_len += ret;
 149                if (from_stdin)
 150                        display_throughput(progress, consumed_bytes + input_len);
 151        } while (input_len < min);
 152        return input_buffer;
 153}
 154
 155static void use(int bytes)
 156{
 157        if (bytes > input_len)
 158                die("used more bytes than were available");
 159        input_crc32 = crc32(input_crc32, input_buffer + input_offset, bytes);
 160        input_len -= bytes;
 161        input_offset += bytes;
 162
 163        /* make sure off_t is sufficiently large not to wrap */
 164        if (consumed_bytes > consumed_bytes + bytes)
 165                die("pack too large for current definition of off_t");
 166        consumed_bytes += bytes;
 167}
 168
 169static const char *open_pack_file(const char *pack_name)
 170{
 171        if (from_stdin) {
 172                input_fd = 0;
 173                if (!pack_name) {
 174                        static char tmpfile[PATH_MAX];
 175                        output_fd = odb_mkstemp(tmpfile, sizeof(tmpfile),
 176                                                "pack/tmp_pack_XXXXXX");
 177                        pack_name = xstrdup(tmpfile);
 178                } else
 179                        output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 180                if (output_fd < 0)
 181                        die_errno("unable to create '%s'", pack_name);
 182                pack_fd = output_fd;
 183        } else {
 184                input_fd = open(pack_name, O_RDONLY);
 185                if (input_fd < 0)
 186                        die_errno("cannot open packfile '%s'", pack_name);
 187                output_fd = -1;
 188                pack_fd = input_fd;
 189        }
 190        git_SHA1_Init(&input_ctx);
 191        return pack_name;
 192}
 193
 194static void parse_pack_header(void)
 195{
 196        struct pack_header *hdr = fill(sizeof(struct pack_header));
 197
 198        /* Header consistency check */
 199        if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 200                die("pack signature mismatch");
 201        if (!pack_version_ok(hdr->hdr_version))
 202                die("pack version %"PRIu32" unsupported",
 203                        ntohl(hdr->hdr_version));
 204
 205        nr_objects = ntohl(hdr->hdr_entries);
 206        use(sizeof(struct pack_header));
 207}
 208
 209static NORETURN void bad_object(unsigned long offset, const char *format,
 210                       ...) __attribute__((format (printf, 2, 3)));
 211
 212static void bad_object(unsigned long offset, const char *format, ...)
 213{
 214        va_list params;
 215        char buf[1024];
 216
 217        va_start(params, format);
 218        vsnprintf(buf, sizeof(buf), format, params);
 219        va_end(params);
 220        die("pack has bad object at offset %lu: %s", offset, buf);
 221}
 222
 223static void free_base_data(struct base_data *c)
 224{
 225        if (c->data) {
 226                free(c->data);
 227                c->data = NULL;
 228                base_cache_used -= c->size;
 229        }
 230}
 231
 232static void prune_base_data(struct base_data *retain)
 233{
 234        struct base_data *b;
 235        for (b = base_cache;
 236             base_cache_used > delta_base_cache_limit && b;
 237             b = b->child) {
 238                if (b->data && b != retain)
 239                        free_base_data(b);
 240        }
 241}
 242
 243static void link_base_data(struct base_data *base, struct base_data *c)
 244{
 245        if (base)
 246                base->child = c;
 247        else
 248                base_cache = c;
 249
 250        c->base = base;
 251        c->child = NULL;
 252        if (c->data)
 253                base_cache_used += c->size;
 254        prune_base_data(c);
 255}
 256
 257static void unlink_base_data(struct base_data *c)
 258{
 259        struct base_data *base = c->base;
 260        if (base)
 261                base->child = NULL;
 262        else
 263                base_cache = NULL;
 264        free_base_data(c);
 265}
 266
 267static void *unpack_entry_data(unsigned long offset, unsigned long size)
 268{
 269        z_stream stream;
 270        void *buf = xmalloc(size);
 271
 272        memset(&stream, 0, sizeof(stream));
 273        stream.next_out = buf;
 274        stream.avail_out = size;
 275        stream.next_in = fill(1);
 276        stream.avail_in = input_len;
 277        git_inflate_init(&stream);
 278
 279        for (;;) {
 280                int ret = git_inflate(&stream, 0);
 281                use(input_len - stream.avail_in);
 282                if (stream.total_out == size && ret == Z_STREAM_END)
 283                        break;
 284                if (ret != Z_OK)
 285                        bad_object(offset, "inflate returned %d", ret);
 286                stream.next_in = fill(1);
 287                stream.avail_in = input_len;
 288        }
 289        git_inflate_end(&stream);
 290        return buf;
 291}
 292
 293static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 294{
 295        unsigned char *p;
 296        unsigned long size, c;
 297        off_t base_offset;
 298        unsigned shift;
 299        void *data;
 300
 301        obj->idx.offset = consumed_bytes;
 302        input_crc32 = crc32(0, Z_NULL, 0);
 303
 304        p = fill(1);
 305        c = *p;
 306        use(1);
 307        obj->type = (c >> 4) & 7;
 308        size = (c & 15);
 309        shift = 4;
 310        while (c & 0x80) {
 311                p = fill(1);
 312                c = *p;
 313                use(1);
 314                size += (c & 0x7f) << shift;
 315                shift += 7;
 316        }
 317        obj->size = size;
 318
 319        switch (obj->type) {
 320        case OBJ_REF_DELTA:
 321                hashcpy(delta_base->sha1, fill(20));
 322                use(20);
 323                break;
 324        case OBJ_OFS_DELTA:
 325                memset(delta_base, 0, sizeof(*delta_base));
 326                p = fill(1);
 327                c = *p;
 328                use(1);
 329                base_offset = c & 127;
 330                while (c & 128) {
 331                        base_offset += 1;
 332                        if (!base_offset || MSB(base_offset, 7))
 333                                bad_object(obj->idx.offset, "offset value overflow for delta base object");
 334                        p = fill(1);
 335                        c = *p;
 336                        use(1);
 337                        base_offset = (base_offset << 7) + (c & 127);
 338                }
 339                delta_base->offset = obj->idx.offset - base_offset;
 340                if (delta_base->offset <= 0 || delta_base->offset >= obj->idx.offset)
 341                        bad_object(obj->idx.offset, "delta base offset is out of bound");
 342                break;
 343        case OBJ_COMMIT:
 344        case OBJ_TREE:
 345        case OBJ_BLOB:
 346        case OBJ_TAG:
 347                break;
 348        default:
 349                bad_object(obj->idx.offset, "unknown object type %d", obj->type);
 350        }
 351        obj->hdr_size = consumed_bytes - obj->idx.offset;
 352
 353        data = unpack_entry_data(obj->idx.offset, obj->size);
 354        obj->idx.crc32 = input_crc32;
 355        return data;
 356}
 357
 358static void *get_data_from_pack(struct object_entry *obj)
 359{
 360        off_t from = obj[0].idx.offset + obj[0].hdr_size;
 361        unsigned long len = obj[1].idx.offset - from;
 362        unsigned long rdy = 0;
 363        unsigned char *src, *data;
 364        z_stream stream;
 365        int st;
 366
 367        src = xmalloc(len);
 368        data = src;
 369        do {
 370                ssize_t n = pread(pack_fd, data + rdy, len - rdy, from + rdy);
 371                if (n < 0)
 372                        die_errno("cannot pread pack file");
 373                if (!n)
 374                        die("premature end of pack file, %lu bytes missing",
 375                            len - rdy);
 376                rdy += n;
 377        } while (rdy < len);
 378        data = xmalloc(obj->size);
 379        memset(&stream, 0, sizeof(stream));
 380        stream.next_out = data;
 381        stream.avail_out = obj->size;
 382        stream.next_in = src;
 383        stream.avail_in = len;
 384        git_inflate_init(&stream);
 385        while ((st = git_inflate(&stream, Z_FINISH)) == Z_OK);
 386        git_inflate_end(&stream);
 387        if (st != Z_STREAM_END || stream.total_out != obj->size)
 388                die("serious inflate inconsistency");
 389        free(src);
 390        return data;
 391}
 392
 393static int find_delta(const union delta_base *base)
 394{
 395        int first = 0, last = nr_deltas;
 396
 397        while (first < last) {
 398                int next = (first + last) / 2;
 399                struct delta_entry *delta = &deltas[next];
 400                int cmp;
 401
 402                cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
 403                if (!cmp)
 404                        return next;
 405                if (cmp < 0) {
 406                        last = next;
 407                        continue;
 408                }
 409                first = next+1;
 410        }
 411        return -first-1;
 412}
 413
 414static void find_delta_children(const union delta_base *base,
 415                                int *first_index, int *last_index)
 416{
 417        int first = find_delta(base);
 418        int last = first;
 419        int end = nr_deltas - 1;
 420
 421        if (first < 0) {
 422                *first_index = 0;
 423                *last_index = -1;
 424                return;
 425        }
 426        while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 427                --first;
 428        while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 429                ++last;
 430        *first_index = first;
 431        *last_index = last;
 432}
 433
 434static void sha1_object(const void *data, unsigned long size,
 435                        enum object_type type, unsigned char *sha1)
 436{
 437        hash_sha1_file(data, size, typename(type), sha1);
 438        if (has_sha1_file(sha1)) {
 439                void *has_data;
 440                enum object_type has_type;
 441                unsigned long has_size;
 442                has_data = read_sha1_file(sha1, &has_type, &has_size);
 443                if (!has_data)
 444                        die("cannot read existing object %s", sha1_to_hex(sha1));
 445                if (size != has_size || type != has_type ||
 446                    memcmp(data, has_data, size) != 0)
 447                        die("SHA1 COLLISION FOUND WITH %s !", sha1_to_hex(sha1));
 448                free(has_data);
 449        }
 450        if (strict) {
 451                if (type == OBJ_BLOB) {
 452                        struct blob *blob = lookup_blob(sha1);
 453                        if (blob)
 454                                blob->object.flags |= FLAG_CHECKED;
 455                        else
 456                                die("invalid blob object %s", sha1_to_hex(sha1));
 457                } else {
 458                        struct object *obj;
 459                        int eaten;
 460                        void *buf = (void *) data;
 461
 462                        /*
 463                         * we do not need to free the memory here, as the
 464                         * buf is deleted by the caller.
 465                         */
 466                        obj = parse_object_buffer(sha1, type, size, buf, &eaten);
 467                        if (!obj)
 468                                die("invalid %s", typename(type));
 469                        if (fsck_object(obj, 1, fsck_error_function))
 470                                die("Error in object");
 471                        if (fsck_walk(obj, mark_link, NULL))
 472                                die("Not all child objects of %s are reachable", sha1_to_hex(obj->sha1));
 473
 474                        if (obj->type == OBJ_TREE) {
 475                                struct tree *item = (struct tree *) obj;
 476                                item->buffer = NULL;
 477                        }
 478                        if (obj->type == OBJ_COMMIT) {
 479                                struct commit *commit = (struct commit *) obj;
 480                                commit->buffer = NULL;
 481                        }
 482                        obj->flags |= FLAG_CHECKED;
 483                }
 484        }
 485}
 486
 487static void *get_base_data(struct base_data *c)
 488{
 489        if (!c->data) {
 490                struct object_entry *obj = c->obj;
 491
 492                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 493                        void *base = get_base_data(c->base);
 494                        void *raw = get_data_from_pack(obj);
 495                        c->data = patch_delta(
 496                                base, c->base->size,
 497                                raw, obj->size,
 498                                &c->size);
 499                        free(raw);
 500                        if (!c->data)
 501                                bad_object(obj->idx.offset, "failed to apply delta");
 502                } else {
 503                        c->data = get_data_from_pack(obj);
 504                        c->size = obj->size;
 505                }
 506
 507                base_cache_used += c->size;
 508                prune_base_data(c);
 509        }
 510        return c->data;
 511}
 512
 513static void resolve_delta(struct object_entry *delta_obj,
 514                          struct base_data *base, struct base_data *result)
 515{
 516        void *base_data, *delta_data;
 517
 518        delta_obj->real_type = base->obj->real_type;
 519        delta_data = get_data_from_pack(delta_obj);
 520        base_data = get_base_data(base);
 521        result->obj = delta_obj;
 522        result->data = patch_delta(base_data, base->size,
 523                                   delta_data, delta_obj->size, &result->size);
 524        free(delta_data);
 525        if (!result->data)
 526                bad_object(delta_obj->idx.offset, "failed to apply delta");
 527        sha1_object(result->data, result->size, delta_obj->real_type,
 528                    delta_obj->idx.sha1);
 529        nr_resolved_deltas++;
 530}
 531
 532static void find_unresolved_deltas(struct base_data *base,
 533                                   struct base_data *prev_base)
 534{
 535        int i, ref_first, ref_last, ofs_first, ofs_last;
 536
 537        /*
 538         * This is a recursive function. Those brackets should help reducing
 539         * stack usage by limiting the scope of the delta_base union.
 540         */
 541        {
 542                union delta_base base_spec;
 543
 544                hashcpy(base_spec.sha1, base->obj->idx.sha1);
 545                find_delta_children(&base_spec, &ref_first, &ref_last);
 546
 547                memset(&base_spec, 0, sizeof(base_spec));
 548                base_spec.offset = base->obj->idx.offset;
 549                find_delta_children(&base_spec, &ofs_first, &ofs_last);
 550        }
 551
 552        if (ref_last == -1 && ofs_last == -1) {
 553                free(base->data);
 554                return;
 555        }
 556
 557        link_base_data(prev_base, base);
 558
 559        for (i = ref_first; i <= ref_last; i++) {
 560                struct object_entry *child = objects + deltas[i].obj_no;
 561                if (child->real_type == OBJ_REF_DELTA) {
 562                        struct base_data result;
 563                        resolve_delta(child, base, &result);
 564                        if (i == ref_last && ofs_last == -1)
 565                                free_base_data(base);
 566                        find_unresolved_deltas(&result, base);
 567                }
 568        }
 569
 570        for (i = ofs_first; i <= ofs_last; i++) {
 571                struct object_entry *child = objects + deltas[i].obj_no;
 572                if (child->real_type == OBJ_OFS_DELTA) {
 573                        struct base_data result;
 574                        resolve_delta(child, base, &result);
 575                        if (i == ofs_last)
 576                                free_base_data(base);
 577                        find_unresolved_deltas(&result, base);
 578                }
 579        }
 580
 581        unlink_base_data(base);
 582}
 583
 584static int compare_delta_entry(const void *a, const void *b)
 585{
 586        const struct delta_entry *delta_a = a;
 587        const struct delta_entry *delta_b = b;
 588        return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
 589}
 590
 591/* Parse all objects and return the pack content SHA1 hash */
 592static void parse_pack_objects(unsigned char *sha1)
 593{
 594        int i;
 595        struct delta_entry *delta = deltas;
 596        struct stat st;
 597
 598        /*
 599         * First pass:
 600         * - find locations of all objects;
 601         * - calculate SHA1 of all non-delta objects;
 602         * - remember base (SHA1 or offset) for all deltas.
 603         */
 604        if (verbose)
 605                progress = start_progress(
 606                                from_stdin ? "Receiving objects" : "Indexing objects",
 607                                nr_objects);
 608        for (i = 0; i < nr_objects; i++) {
 609                struct object_entry *obj = &objects[i];
 610                void *data = unpack_raw_entry(obj, &delta->base);
 611                obj->real_type = obj->type;
 612                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 613                        nr_deltas++;
 614                        delta->obj_no = i;
 615                        delta++;
 616                } else
 617                        sha1_object(data, obj->size, obj->type, obj->idx.sha1);
 618                free(data);
 619                display_progress(progress, i+1);
 620        }
 621        objects[i].idx.offset = consumed_bytes;
 622        stop_progress(&progress);
 623
 624        /* Check pack integrity */
 625        flush();
 626        git_SHA1_Final(sha1, &input_ctx);
 627        if (hashcmp(fill(20), sha1))
 628                die("pack is corrupted (SHA1 mismatch)");
 629        use(20);
 630
 631        /* If input_fd is a file, we should have reached its end now. */
 632        if (fstat(input_fd, &st))
 633                die_errno("cannot fstat packfile");
 634        if (S_ISREG(st.st_mode) &&
 635                        lseek(input_fd, 0, SEEK_CUR) - input_len != st.st_size)
 636                die("pack has junk at the end");
 637
 638        if (!nr_deltas)
 639                return;
 640
 641        /* Sort deltas by base SHA1/offset for fast searching */
 642        qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 643              compare_delta_entry);
 644
 645        /*
 646         * Second pass:
 647         * - for all non-delta objects, look if it is used as a base for
 648         *   deltas;
 649         * - if used as a base, uncompress the object and apply all deltas,
 650         *   recursively checking if the resulting object is used as a base
 651         *   for some more deltas.
 652         */
 653        if (verbose)
 654                progress = start_progress("Resolving deltas", nr_deltas);
 655        for (i = 0; i < nr_objects; i++) {
 656                struct object_entry *obj = &objects[i];
 657                struct base_data base_obj;
 658
 659                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
 660                        continue;
 661                base_obj.obj = obj;
 662                base_obj.data = NULL;
 663                find_unresolved_deltas(&base_obj, NULL);
 664                display_progress(progress, nr_resolved_deltas);
 665        }
 666}
 667
 668static int write_compressed(struct sha1file *f, void *in, unsigned int size)
 669{
 670        z_stream stream;
 671        unsigned long maxsize;
 672        void *out;
 673
 674        memset(&stream, 0, sizeof(stream));
 675        deflateInit(&stream, zlib_compression_level);
 676        maxsize = deflateBound(&stream, size);
 677        out = xmalloc(maxsize);
 678
 679        /* Compress it */
 680        stream.next_in = in;
 681        stream.avail_in = size;
 682        stream.next_out = out;
 683        stream.avail_out = maxsize;
 684        while (deflate(&stream, Z_FINISH) == Z_OK);
 685        deflateEnd(&stream);
 686
 687        size = stream.total_out;
 688        sha1write(f, out, size);
 689        free(out);
 690        return size;
 691}
 692
 693static struct object_entry *append_obj_to_pack(struct sha1file *f,
 694                               const unsigned char *sha1, void *buf,
 695                               unsigned long size, enum object_type type)
 696{
 697        struct object_entry *obj = &objects[nr_objects++];
 698        unsigned char header[10];
 699        unsigned long s = size;
 700        int n = 0;
 701        unsigned char c = (type << 4) | (s & 15);
 702        s >>= 4;
 703        while (s) {
 704                header[n++] = c | 0x80;
 705                c = s & 0x7f;
 706                s >>= 7;
 707        }
 708        header[n++] = c;
 709        crc32_begin(f);
 710        sha1write(f, header, n);
 711        obj[0].size = size;
 712        obj[0].hdr_size = n;
 713        obj[0].type = type;
 714        obj[0].real_type = type;
 715        obj[1].idx.offset = obj[0].idx.offset + n;
 716        obj[1].idx.offset += write_compressed(f, buf, size);
 717        obj[0].idx.crc32 = crc32_end(f);
 718        sha1flush(f);
 719        hashcpy(obj->idx.sha1, sha1);
 720        return obj;
 721}
 722
 723static int delta_pos_compare(const void *_a, const void *_b)
 724{
 725        struct delta_entry *a = *(struct delta_entry **)_a;
 726        struct delta_entry *b = *(struct delta_entry **)_b;
 727        return a->obj_no - b->obj_no;
 728}
 729
 730static void fix_unresolved_deltas(struct sha1file *f, int nr_unresolved)
 731{
 732        struct delta_entry **sorted_by_pos;
 733        int i, n = 0;
 734
 735        /*
 736         * Since many unresolved deltas may well be themselves base objects
 737         * for more unresolved deltas, we really want to include the
 738         * smallest number of base objects that would cover as much delta
 739         * as possible by picking the
 740         * trunc deltas first, allowing for other deltas to resolve without
 741         * additional base objects.  Since most base objects are to be found
 742         * before deltas depending on them, a good heuristic is to start
 743         * resolving deltas in the same order as their position in the pack.
 744         */
 745        sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 746        for (i = 0; i < nr_deltas; i++) {
 747                if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 748                        continue;
 749                sorted_by_pos[n++] = &deltas[i];
 750        }
 751        qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 752
 753        for (i = 0; i < n; i++) {
 754                struct delta_entry *d = sorted_by_pos[i];
 755                enum object_type type;
 756                struct base_data base_obj;
 757
 758                if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 759                        continue;
 760                base_obj.data = read_sha1_file(d->base.sha1, &type, &base_obj.size);
 761                if (!base_obj.data)
 762                        continue;
 763
 764                if (check_sha1_signature(d->base.sha1, base_obj.data,
 765                                base_obj.size, typename(type)))
 766                        die("local object %s is corrupt", sha1_to_hex(d->base.sha1));
 767                base_obj.obj = append_obj_to_pack(f, d->base.sha1,
 768                                        base_obj.data, base_obj.size, type);
 769                find_unresolved_deltas(&base_obj, NULL);
 770                display_progress(progress, nr_resolved_deltas);
 771        }
 772        free(sorted_by_pos);
 773}
 774
 775static void final(const char *final_pack_name, const char *curr_pack_name,
 776                  const char *final_index_name, const char *curr_index_name,
 777                  const char *keep_name, const char *keep_msg,
 778                  unsigned char *sha1)
 779{
 780        const char *report = "pack";
 781        char name[PATH_MAX];
 782        int err;
 783
 784        if (!from_stdin) {
 785                close(input_fd);
 786        } else {
 787                fsync_or_die(output_fd, curr_pack_name);
 788                err = close(output_fd);
 789                if (err)
 790                        die_errno("error while closing pack file");
 791        }
 792
 793        if (keep_msg) {
 794                int keep_fd, keep_msg_len = strlen(keep_msg);
 795
 796                if (!keep_name)
 797                        keep_fd = odb_pack_keep(name, sizeof(name), sha1);
 798                else
 799                        keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 800
 801                if (keep_fd < 0) {
 802                        if (errno != EEXIST)
 803                                die_errno("cannot write keep file '%s'",
 804                                          keep_name);
 805                } else {
 806                        if (keep_msg_len > 0) {
 807                                write_or_die(keep_fd, keep_msg, keep_msg_len);
 808                                write_or_die(keep_fd, "\n", 1);
 809                        }
 810                        if (close(keep_fd) != 0)
 811                                die_errno("cannot close written keep file '%s'",
 812                                    keep_name);
 813                        report = "keep";
 814                }
 815        }
 816
 817        if (final_pack_name != curr_pack_name) {
 818                if (!final_pack_name) {
 819                        snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 820                                 get_object_directory(), sha1_to_hex(sha1));
 821                        final_pack_name = name;
 822                }
 823                if (move_temp_to_file(curr_pack_name, final_pack_name))
 824                        die("cannot store pack file");
 825        } else if (from_stdin)
 826                chmod(final_pack_name, 0444);
 827
 828        if (final_index_name != curr_index_name) {
 829                if (!final_index_name) {
 830                        snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 831                                 get_object_directory(), sha1_to_hex(sha1));
 832                        final_index_name = name;
 833                }
 834                if (move_temp_to_file(curr_index_name, final_index_name))
 835                        die("cannot store index file");
 836        } else
 837                chmod(final_index_name, 0444);
 838
 839        if (!from_stdin) {
 840                printf("%s\n", sha1_to_hex(sha1));
 841        } else {
 842                char buf[48];
 843                int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 844                                   report, sha1_to_hex(sha1));
 845                write_or_die(1, buf, len);
 846
 847                /*
 848                 * Let's just mimic git-unpack-objects here and write
 849                 * the last part of the input buffer to stdout.
 850                 */
 851                while (input_len) {
 852                        err = xwrite(1, input_buffer + input_offset, input_len);
 853                        if (err <= 0)
 854                                break;
 855                        input_len -= err;
 856                        input_offset += err;
 857                }
 858        }
 859}
 860
 861static int git_index_pack_config(const char *k, const char *v, void *cb)
 862{
 863        if (!strcmp(k, "pack.indexversion")) {
 864                pack_idx_default_version = git_config_int(k, v);
 865                if (pack_idx_default_version > 2)
 866                        die("bad pack.indexversion=%"PRIu32,
 867                                pack_idx_default_version);
 868                return 0;
 869        }
 870        return git_default_config(k, v, cb);
 871}
 872
 873int cmd_index_pack(int argc, const char **argv, const char *prefix)
 874{
 875        int i, fix_thin_pack = 0;
 876        const char *curr_pack, *curr_index;
 877        const char *index_name = NULL, *pack_name = NULL;
 878        const char *keep_name = NULL, *keep_msg = NULL;
 879        char *index_name_buf = NULL, *keep_name_buf = NULL;
 880        struct pack_idx_entry **idx_objects;
 881        unsigned char pack_sha1[20];
 882
 883        if (argc == 2 && !strcmp(argv[1], "-h"))
 884                usage(index_pack_usage);
 885
 886        /*
 887         * We wish to read the repository's config file if any, and
 888         * for that it is necessary to call setup_git_directory_gently().
 889         * However if the cwd was inside .git/objects/pack/ then we need
 890         * to go back there or all the pack name arguments will be wrong.
 891         * And in that case we cannot rely on any prefix returned by
 892         * setup_git_directory_gently() either.
 893         */
 894        {
 895                char cwd[PATH_MAX+1];
 896                int nongit;
 897
 898                if (!getcwd(cwd, sizeof(cwd)-1))
 899                        die("Unable to get current working directory");
 900                setup_git_directory_gently(&nongit);
 901                git_config(git_index_pack_config, NULL);
 902                if (chdir(cwd))
 903                        die("Cannot come back to cwd");
 904        }
 905
 906        for (i = 1; i < argc; i++) {
 907                const char *arg = argv[i];
 908
 909                if (*arg == '-') {
 910                        if (!strcmp(arg, "--stdin")) {
 911                                from_stdin = 1;
 912                        } else if (!strcmp(arg, "--fix-thin")) {
 913                                fix_thin_pack = 1;
 914                        } else if (!strcmp(arg, "--strict")) {
 915                                strict = 1;
 916                        } else if (!strcmp(arg, "--keep")) {
 917                                keep_msg = "";
 918                        } else if (!prefixcmp(arg, "--keep=")) {
 919                                keep_msg = arg + 7;
 920                        } else if (!prefixcmp(arg, "--pack_header=")) {
 921                                struct pack_header *hdr;
 922                                char *c;
 923
 924                                hdr = (struct pack_header *)input_buffer;
 925                                hdr->hdr_signature = htonl(PACK_SIGNATURE);
 926                                hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 927                                if (*c != ',')
 928                                        die("bad %s", arg);
 929                                hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 930                                if (*c)
 931                                        die("bad %s", arg);
 932                                input_len = sizeof(*hdr);
 933                        } else if (!strcmp(arg, "-v")) {
 934                                verbose = 1;
 935                        } else if (!strcmp(arg, "-o")) {
 936                                if (index_name || (i+1) >= argc)
 937                                        usage(index_pack_usage);
 938                                index_name = argv[++i];
 939                        } else if (!prefixcmp(arg, "--index-version=")) {
 940                                char *c;
 941                                pack_idx_default_version = strtoul(arg + 16, &c, 10);
 942                                if (pack_idx_default_version > 2)
 943                                        die("bad %s", arg);
 944                                if (*c == ',')
 945                                        pack_idx_off32_limit = strtoul(c+1, &c, 0);
 946                                if (*c || pack_idx_off32_limit & 0x80000000)
 947                                        die("bad %s", arg);
 948                        } else
 949                                usage(index_pack_usage);
 950                        continue;
 951                }
 952
 953                if (pack_name)
 954                        usage(index_pack_usage);
 955                pack_name = arg;
 956        }
 957
 958        if (!pack_name && !from_stdin)
 959                usage(index_pack_usage);
 960        if (fix_thin_pack && !from_stdin)
 961                die("--fix-thin cannot be used without --stdin");
 962        if (!index_name && pack_name) {
 963                int len = strlen(pack_name);
 964                if (!has_extension(pack_name, ".pack"))
 965                        die("packfile name '%s' does not end with '.pack'",
 966                            pack_name);
 967                index_name_buf = xmalloc(len);
 968                memcpy(index_name_buf, pack_name, len - 5);
 969                strcpy(index_name_buf + len - 5, ".idx");
 970                index_name = index_name_buf;
 971        }
 972        if (keep_msg && !keep_name && pack_name) {
 973                int len = strlen(pack_name);
 974                if (!has_extension(pack_name, ".pack"))
 975                        die("packfile name '%s' does not end with '.pack'",
 976                            pack_name);
 977                keep_name_buf = xmalloc(len);
 978                memcpy(keep_name_buf, pack_name, len - 5);
 979                strcpy(keep_name_buf + len - 5, ".keep");
 980                keep_name = keep_name_buf;
 981        }
 982
 983        curr_pack = open_pack_file(pack_name);
 984        parse_pack_header();
 985        objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
 986        deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
 987        parse_pack_objects(pack_sha1);
 988        if (nr_deltas == nr_resolved_deltas) {
 989                stop_progress(&progress);
 990                /* Flush remaining pack final 20-byte SHA1. */
 991                flush();
 992        } else {
 993                if (fix_thin_pack) {
 994                        struct sha1file *f;
 995                        unsigned char read_sha1[20], tail_sha1[20];
 996                        char msg[48];
 997                        int nr_unresolved = nr_deltas - nr_resolved_deltas;
 998                        int nr_objects_initial = nr_objects;
 999                        if (nr_unresolved <= 0)
1000                                die("confusion beyond insanity");
1001                        objects = xrealloc(objects,
1002                                           (nr_objects + nr_unresolved + 1)
1003                                           * sizeof(*objects));
1004                        f = sha1fd(output_fd, curr_pack);
1005                        fix_unresolved_deltas(f, nr_unresolved);
1006                        sprintf(msg, "completed with %d local objects",
1007                                nr_objects - nr_objects_initial);
1008                        stop_progress_msg(&progress, msg);
1009                        sha1close(f, tail_sha1, 0);
1010                        hashcpy(read_sha1, pack_sha1);
1011                        fixup_pack_header_footer(output_fd, pack_sha1,
1012                                                 curr_pack, nr_objects,
1013                                                 read_sha1, consumed_bytes-20);
1014                        if (hashcmp(read_sha1, tail_sha1) != 0)
1015                                die("Unexpected tail checksum for %s "
1016                                    "(disk corruption?)", curr_pack);
1017                }
1018                if (nr_deltas != nr_resolved_deltas)
1019                        die("pack has %d unresolved deltas",
1020                            nr_deltas - nr_resolved_deltas);
1021        }
1022        free(deltas);
1023        if (strict)
1024                check_objects();
1025
1026        idx_objects = xmalloc((nr_objects) * sizeof(struct pack_idx_entry *));
1027        for (i = 0; i < nr_objects; i++)
1028                idx_objects[i] = &objects[i].idx;
1029        curr_index = write_idx_file(index_name, idx_objects, nr_objects, pack_sha1);
1030        free(idx_objects);
1031
1032        final(pack_name, curr_pack,
1033                index_name, curr_index,
1034                keep_name, keep_msg,
1035                pack_sha1);
1036        free(objects);
1037        free(index_name_buf);
1038        free(keep_name_buf);
1039        if (pack_name == NULL)
1040                free((void *) curr_pack);
1041        if (index_name == NULL)
1042                free((void *) curr_index);
1043
1044        return 0;
1045}