Andrew's git / gitweb.git / index-pack.c
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index-pack.con commit Allow the user to control the verbosity of merge-recursive. (8c3275a)
   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
  10static const char index_pack_usage[] =
  11"git-index-pack [-v] [-o <index-file>] [{ ---keep | --keep=<msg> }] { <pack-file> | --stdin [--fix-thin] [<pack-file>] }";
  12
  13struct object_entry
  14{
  15        unsigned long offset;
  16        unsigned long size;
  17        unsigned int hdr_size;
  18        enum object_type type;
  19        enum object_type real_type;
  20        unsigned char sha1[20];
  21};
  22
  23union delta_base {
  24        unsigned char sha1[20];
  25        unsigned long offset;
  26};
  27
  28/*
  29 * Even if sizeof(union delta_base) == 24 on 64-bit archs, we really want
  30 * to memcmp() only the first 20 bytes.
  31 */
  32#define UNION_BASE_SZ   20
  33
  34struct delta_entry
  35{
  36        union delta_base base;
  37        int obj_no;
  38};
  39
  40static struct object_entry *objects;
  41static struct delta_entry *deltas;
  42static int nr_objects;
  43static int nr_deltas;
  44static int nr_resolved_deltas;
  45
  46static int from_stdin;
  47static int verbose;
  48
  49static volatile sig_atomic_t progress_update;
  50
  51static void progress_interval(int signum)
  52{
  53        progress_update = 1;
  54}
  55
  56static void setup_progress_signal(void)
  57{
  58        struct sigaction sa;
  59        struct itimerval v;
  60
  61        memset(&sa, 0, sizeof(sa));
  62        sa.sa_handler = progress_interval;
  63        sigemptyset(&sa.sa_mask);
  64        sa.sa_flags = SA_RESTART;
  65        sigaction(SIGALRM, &sa, NULL);
  66
  67        v.it_interval.tv_sec = 1;
  68        v.it_interval.tv_usec = 0;
  69        v.it_value = v.it_interval;
  70        setitimer(ITIMER_REAL, &v, NULL);
  71
  72}
  73
  74static unsigned display_progress(unsigned n, unsigned total, unsigned last_pc)
  75{
  76        unsigned percent = n * 100 / total;
  77        if (percent != last_pc || progress_update) {
  78                fprintf(stderr, "%4u%% (%u/%u) done\r", percent, n, total);
  79                progress_update = 0;
  80        }
  81        return percent;
  82}
  83
  84/* We always read in 4kB chunks. */
  85static unsigned char input_buffer[4096];
  86static unsigned long input_offset, input_len, consumed_bytes;
  87static SHA_CTX input_ctx;
  88static int input_fd, output_fd, pack_fd;
  89
  90/* Discard current buffer used content. */
  91static void flush(void)
  92{
  93        if (input_offset) {
  94                if (output_fd >= 0)
  95                        write_or_die(output_fd, input_buffer, input_offset);
  96                SHA1_Update(&input_ctx, input_buffer, input_offset);
  97                memmove(input_buffer, input_buffer + input_offset, input_len);
  98                input_offset = 0;
  99        }
 100}
 101
 102/*
 103 * Make sure at least "min" bytes are available in the buffer, and
 104 * return the pointer to the buffer.
 105 */
 106static void *fill(int min)
 107{
 108        if (min <= input_len)
 109                return input_buffer + input_offset;
 110        if (min > sizeof(input_buffer))
 111                die("cannot fill %d bytes", min);
 112        flush();
 113        do {
 114                int ret = xread(input_fd, input_buffer + input_len,
 115                                sizeof(input_buffer) - input_len);
 116                if (ret <= 0) {
 117                        if (!ret)
 118                                die("early EOF");
 119                        die("read error on input: %s", strerror(errno));
 120                }
 121                input_len += ret;
 122        } while (input_len < min);
 123        return input_buffer;
 124}
 125
 126static void use(int bytes)
 127{
 128        if (bytes > input_len)
 129                die("used more bytes than were available");
 130        input_len -= bytes;
 131        input_offset += bytes;
 132        consumed_bytes += bytes;
 133}
 134
 135static const char *open_pack_file(const char *pack_name)
 136{
 137        if (from_stdin) {
 138                input_fd = 0;
 139                if (!pack_name) {
 140                        static char tmpfile[PATH_MAX];
 141                        snprintf(tmpfile, sizeof(tmpfile),
 142                                 "%s/pack_XXXXXX", get_object_directory());
 143                        output_fd = mkstemp(tmpfile);
 144                        pack_name = xstrdup(tmpfile);
 145                } else
 146                        output_fd = open(pack_name, O_CREAT|O_EXCL|O_RDWR, 0600);
 147                if (output_fd < 0)
 148                        die("unable to create %s: %s\n", pack_name, strerror(errno));
 149                pack_fd = output_fd;
 150        } else {
 151                input_fd = open(pack_name, O_RDONLY);
 152                if (input_fd < 0)
 153                        die("cannot open packfile '%s': %s",
 154                            pack_name, strerror(errno));
 155                output_fd = -1;
 156                pack_fd = input_fd;
 157        }
 158        SHA1_Init(&input_ctx);
 159        return pack_name;
 160}
 161
 162static void parse_pack_header(void)
 163{
 164        struct pack_header *hdr = fill(sizeof(struct pack_header));
 165
 166        /* Header consistency check */
 167        if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
 168                die("pack signature mismatch");
 169        if (!pack_version_ok(hdr->hdr_version))
 170                die("pack version %d unsupported", ntohl(hdr->hdr_version));
 171
 172        nr_objects = ntohl(hdr->hdr_entries);
 173        use(sizeof(struct pack_header));
 174}
 175
 176static void bad_object(unsigned long offset, const char *format,
 177                       ...) NORETURN __attribute__((format (printf, 2, 3)));
 178
 179static void bad_object(unsigned long offset, const char *format, ...)
 180{
 181        va_list params;
 182        char buf[1024];
 183
 184        va_start(params, format);
 185        vsnprintf(buf, sizeof(buf), format, params);
 186        va_end(params);
 187        die("pack has bad object at offset %lu: %s", offset, buf);
 188}
 189
 190static void *unpack_entry_data(unsigned long offset, unsigned long size)
 191{
 192        z_stream stream;
 193        void *buf = xmalloc(size);
 194
 195        memset(&stream, 0, sizeof(stream));
 196        stream.next_out = buf;
 197        stream.avail_out = size;
 198        stream.next_in = fill(1);
 199        stream.avail_in = input_len;
 200        inflateInit(&stream);
 201
 202        for (;;) {
 203                int ret = inflate(&stream, 0);
 204                use(input_len - stream.avail_in);
 205                if (stream.total_out == size && ret == Z_STREAM_END)
 206                        break;
 207                if (ret != Z_OK)
 208                        bad_object(offset, "inflate returned %d", ret);
 209                stream.next_in = fill(1);
 210                stream.avail_in = input_len;
 211        }
 212        inflateEnd(&stream);
 213        return buf;
 214}
 215
 216static void *unpack_raw_entry(struct object_entry *obj, union delta_base *delta_base)
 217{
 218        unsigned char *p, c;
 219        unsigned long size, base_offset;
 220        unsigned shift;
 221
 222        obj->offset = consumed_bytes;
 223
 224        p = fill(1);
 225        c = *p;
 226        use(1);
 227        obj->type = (c >> 4) & 7;
 228        size = (c & 15);
 229        shift = 4;
 230        while (c & 0x80) {
 231                p = fill(1);
 232                c = *p;
 233                use(1);
 234                size += (c & 0x7fUL) << shift;
 235                shift += 7;
 236        }
 237        obj->size = size;
 238
 239        switch (obj->type) {
 240        case OBJ_REF_DELTA:
 241                hashcpy(delta_base->sha1, fill(20));
 242                use(20);
 243                break;
 244        case OBJ_OFS_DELTA:
 245                memset(delta_base, 0, sizeof(*delta_base));
 246                p = fill(1);
 247                c = *p;
 248                use(1);
 249                base_offset = c & 127;
 250                while (c & 128) {
 251                        base_offset += 1;
 252                        if (!base_offset || base_offset & ~(~0UL >> 7))
 253                                bad_object(obj->offset, "offset value overflow for delta base object");
 254                        p = fill(1);
 255                        c = *p;
 256                        use(1);
 257                        base_offset = (base_offset << 7) + (c & 127);
 258                }
 259                delta_base->offset = obj->offset - base_offset;
 260                if (delta_base->offset >= obj->offset)
 261                        bad_object(obj->offset, "delta base offset is out of bound");
 262                break;
 263        case OBJ_COMMIT:
 264        case OBJ_TREE:
 265        case OBJ_BLOB:
 266        case OBJ_TAG:
 267                break;
 268        default:
 269                bad_object(obj->offset, "unknown object type %d", obj->type);
 270        }
 271        obj->hdr_size = consumed_bytes - obj->offset;
 272
 273        return unpack_entry_data(obj->offset, obj->size);
 274}
 275
 276static void *get_data_from_pack(struct object_entry *obj)
 277{
 278        unsigned long from = obj[0].offset + obj[0].hdr_size;
 279        unsigned long len = obj[1].offset - from;
 280        unsigned char *src, *data;
 281        z_stream stream;
 282        int st;
 283
 284        src = xmalloc(len);
 285        if (pread(pack_fd, src, len, from) != len)
 286                die("cannot pread pack file: %s", strerror(errno));
 287        data = xmalloc(obj->size);
 288        memset(&stream, 0, sizeof(stream));
 289        stream.next_out = data;
 290        stream.avail_out = obj->size;
 291        stream.next_in = src;
 292        stream.avail_in = len;
 293        inflateInit(&stream);
 294        while ((st = inflate(&stream, Z_FINISH)) == Z_OK);
 295        inflateEnd(&stream);
 296        if (st != Z_STREAM_END || stream.total_out != obj->size)
 297                die("serious inflate inconsistency");
 298        free(src);
 299        return data;
 300}
 301
 302static int find_delta(const union delta_base *base)
 303{
 304        int first = 0, last = nr_deltas;
 305
 306        while (first < last) {
 307                int next = (first + last) / 2;
 308                struct delta_entry *delta = &deltas[next];
 309                int cmp;
 310
 311                cmp = memcmp(base, &delta->base, UNION_BASE_SZ);
 312                if (!cmp)
 313                        return next;
 314                if (cmp < 0) {
 315                        last = next;
 316                        continue;
 317                }
 318                first = next+1;
 319        }
 320        return -first-1;
 321}
 322
 323static int find_delta_children(const union delta_base *base,
 324                               int *first_index, int *last_index)
 325{
 326        int first = find_delta(base);
 327        int last = first;
 328        int end = nr_deltas - 1;
 329
 330        if (first < 0)
 331                return -1;
 332        while (first > 0 && !memcmp(&deltas[first - 1].base, base, UNION_BASE_SZ))
 333                --first;
 334        while (last < end && !memcmp(&deltas[last + 1].base, base, UNION_BASE_SZ))
 335                ++last;
 336        *first_index = first;
 337        *last_index = last;
 338        return 0;
 339}
 340
 341static void sha1_object(const void *data, unsigned long size,
 342                        enum object_type type, unsigned char *sha1)
 343{
 344        SHA_CTX ctx;
 345        char header[50];
 346        int header_size;
 347        const char *type_str;
 348
 349        switch (type) {
 350        case OBJ_COMMIT: type_str = commit_type; break;
 351        case OBJ_TREE:   type_str = tree_type; break;
 352        case OBJ_BLOB:   type_str = blob_type; break;
 353        case OBJ_TAG:    type_str = tag_type; break;
 354        default:
 355                die("bad type %d", type);
 356        }
 357
 358        header_size = sprintf(header, "%s %lu", type_str, size) + 1;
 359
 360        SHA1_Init(&ctx);
 361        SHA1_Update(&ctx, header, header_size);
 362        SHA1_Update(&ctx, data, size);
 363        SHA1_Final(sha1, &ctx);
 364}
 365
 366static void resolve_delta(struct object_entry *delta_obj, void *base_data,
 367                          unsigned long base_size, enum object_type type)
 368{
 369        void *delta_data;
 370        unsigned long delta_size;
 371        void *result;
 372        unsigned long result_size;
 373        union delta_base delta_base;
 374        int j, first, last;
 375
 376        delta_obj->real_type = type;
 377        delta_data = get_data_from_pack(delta_obj);
 378        delta_size = delta_obj->size;
 379        result = patch_delta(base_data, base_size, delta_data, delta_size,
 380                             &result_size);
 381        free(delta_data);
 382        if (!result)
 383                bad_object(delta_obj->offset, "failed to apply delta");
 384        sha1_object(result, result_size, type, delta_obj->sha1);
 385        nr_resolved_deltas++;
 386
 387        hashcpy(delta_base.sha1, delta_obj->sha1);
 388        if (!find_delta_children(&delta_base, &first, &last)) {
 389                for (j = first; j <= last; j++) {
 390                        struct object_entry *child = objects + deltas[j].obj_no;
 391                        if (child->real_type == OBJ_REF_DELTA)
 392                                resolve_delta(child, result, result_size, type);
 393                }
 394        }
 395
 396        memset(&delta_base, 0, sizeof(delta_base));
 397        delta_base.offset = delta_obj->offset;
 398        if (!find_delta_children(&delta_base, &first, &last)) {
 399                for (j = first; j <= last; j++) {
 400                        struct object_entry *child = objects + deltas[j].obj_no;
 401                        if (child->real_type == OBJ_OFS_DELTA)
 402                                resolve_delta(child, result, result_size, type);
 403                }
 404        }
 405
 406        free(result);
 407}
 408
 409static int compare_delta_entry(const void *a, const void *b)
 410{
 411        const struct delta_entry *delta_a = a;
 412        const struct delta_entry *delta_b = b;
 413        return memcmp(&delta_a->base, &delta_b->base, UNION_BASE_SZ);
 414}
 415
 416/* Parse all objects and return the pack content SHA1 hash */
 417static void parse_pack_objects(unsigned char *sha1)
 418{
 419        int i, percent = -1;
 420        struct delta_entry *delta = deltas;
 421        void *data;
 422        struct stat st;
 423
 424        /*
 425         * First pass:
 426         * - find locations of all objects;
 427         * - calculate SHA1 of all non-delta objects;
 428         * - remember base (SHA1 or offset) for all deltas.
 429         */
 430        if (verbose)
 431                fprintf(stderr, "Indexing %d objects.\n", nr_objects);
 432        for (i = 0; i < nr_objects; i++) {
 433                struct object_entry *obj = &objects[i];
 434                data = unpack_raw_entry(obj, &delta->base);
 435                obj->real_type = obj->type;
 436                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA) {
 437                        nr_deltas++;
 438                        delta->obj_no = i;
 439                        delta++;
 440                } else
 441                        sha1_object(data, obj->size, obj->type, obj->sha1);
 442                free(data);
 443                if (verbose)
 444                        percent = display_progress(i+1, nr_objects, percent);
 445        }
 446        objects[i].offset = consumed_bytes;
 447        if (verbose)
 448                fputc('\n', stderr);
 449
 450        /* Check pack integrity */
 451        flush();
 452        SHA1_Final(sha1, &input_ctx);
 453        if (hashcmp(fill(20), sha1))
 454                die("pack is corrupted (SHA1 mismatch)");
 455        use(20);
 456
 457        /* If input_fd is a file, we should have reached its end now. */
 458        if (fstat(input_fd, &st))
 459                die("cannot fstat packfile: %s", strerror(errno));
 460        if (S_ISREG(st.st_mode) && st.st_size != consumed_bytes)
 461                die("pack has junk at the end");
 462
 463        if (!nr_deltas)
 464                return;
 465
 466        /* Sort deltas by base SHA1/offset for fast searching */
 467        qsort(deltas, nr_deltas, sizeof(struct delta_entry),
 468              compare_delta_entry);
 469
 470        /*
 471         * Second pass:
 472         * - for all non-delta objects, look if it is used as a base for
 473         *   deltas;
 474         * - if used as a base, uncompress the object and apply all deltas,
 475         *   recursively checking if the resulting object is used as a base
 476         *   for some more deltas.
 477         */
 478        if (verbose)
 479                fprintf(stderr, "Resolving %d deltas.\n", nr_deltas);
 480        for (i = 0; i < nr_objects; i++) {
 481                struct object_entry *obj = &objects[i];
 482                union delta_base base;
 483                int j, ref, ref_first, ref_last, ofs, ofs_first, ofs_last;
 484
 485                if (obj->type == OBJ_REF_DELTA || obj->type == OBJ_OFS_DELTA)
 486                        continue;
 487                hashcpy(base.sha1, obj->sha1);
 488                ref = !find_delta_children(&base, &ref_first, &ref_last);
 489                memset(&base, 0, sizeof(base));
 490                base.offset = obj->offset;
 491                ofs = !find_delta_children(&base, &ofs_first, &ofs_last);
 492                if (!ref && !ofs)
 493                        continue;
 494                data = get_data_from_pack(obj);
 495                if (ref)
 496                        for (j = ref_first; j <= ref_last; j++) {
 497                                struct object_entry *child = objects + deltas[j].obj_no;
 498                                if (child->real_type == OBJ_REF_DELTA)
 499                                        resolve_delta(child, data,
 500                                                      obj->size, obj->type);
 501                        }
 502                if (ofs)
 503                        for (j = ofs_first; j <= ofs_last; j++) {
 504                                struct object_entry *child = objects + deltas[j].obj_no;
 505                                if (child->real_type == OBJ_OFS_DELTA)
 506                                        resolve_delta(child, data,
 507                                                      obj->size, obj->type);
 508                        }
 509                free(data);
 510                if (verbose)
 511                        percent = display_progress(nr_resolved_deltas,
 512                                                   nr_deltas, percent);
 513        }
 514        if (verbose && nr_resolved_deltas == nr_deltas)
 515                fputc('\n', stderr);
 516}
 517
 518static int write_compressed(int fd, void *in, unsigned int size)
 519{
 520        z_stream stream;
 521        unsigned long maxsize;
 522        void *out;
 523
 524        memset(&stream, 0, sizeof(stream));
 525        deflateInit(&stream, zlib_compression_level);
 526        maxsize = deflateBound(&stream, size);
 527        out = xmalloc(maxsize);
 528
 529        /* Compress it */
 530        stream.next_in = in;
 531        stream.avail_in = size;
 532        stream.next_out = out;
 533        stream.avail_out = maxsize;
 534        while (deflate(&stream, Z_FINISH) == Z_OK);
 535        deflateEnd(&stream);
 536
 537        size = stream.total_out;
 538        write_or_die(fd, out, size);
 539        free(out);
 540        return size;
 541}
 542
 543static void append_obj_to_pack(void *buf,
 544                               unsigned long size, enum object_type type)
 545{
 546        struct object_entry *obj = &objects[nr_objects++];
 547        unsigned char header[10];
 548        unsigned long s = size;
 549        int n = 0;
 550        unsigned char c = (type << 4) | (s & 15);
 551        s >>= 4;
 552        while (s) {
 553                header[n++] = c | 0x80;
 554                c = s & 0x7f;
 555                s >>= 7;
 556        }
 557        header[n++] = c;
 558        write_or_die(output_fd, header, n);
 559        obj[1].offset = obj[0].offset + n;
 560        obj[1].offset += write_compressed(output_fd, buf, size);
 561        sha1_object(buf, size, type, obj->sha1);
 562}
 563
 564static int delta_pos_compare(const void *_a, const void *_b)
 565{
 566        struct delta_entry *a = *(struct delta_entry **)_a;
 567        struct delta_entry *b = *(struct delta_entry **)_b;
 568        return a->obj_no - b->obj_no;
 569}
 570
 571static void fix_unresolved_deltas(int nr_unresolved)
 572{
 573        struct delta_entry **sorted_by_pos;
 574        int i, n = 0, percent = -1;
 575
 576        /*
 577         * Since many unresolved deltas may well be themselves base objects
 578         * for more unresolved deltas, we really want to include the
 579         * smallest number of base objects that would cover as much delta
 580         * as possible by picking the
 581         * trunc deltas first, allowing for other deltas to resolve without
 582         * additional base objects.  Since most base objects are to be found
 583         * before deltas depending on them, a good heuristic is to start
 584         * resolving deltas in the same order as their position in the pack.
 585         */
 586        sorted_by_pos = xmalloc(nr_unresolved * sizeof(*sorted_by_pos));
 587        for (i = 0; i < nr_deltas; i++) {
 588                if (objects[deltas[i].obj_no].real_type != OBJ_REF_DELTA)
 589                        continue;
 590                sorted_by_pos[n++] = &deltas[i];
 591        }
 592        qsort(sorted_by_pos, n, sizeof(*sorted_by_pos), delta_pos_compare);
 593
 594        for (i = 0; i < n; i++) {
 595                struct delta_entry *d = sorted_by_pos[i];
 596                void *data;
 597                unsigned long size;
 598                char type[10];
 599                enum object_type obj_type;
 600                int j, first, last;
 601
 602                if (objects[d->obj_no].real_type != OBJ_REF_DELTA)
 603                        continue;
 604                data = read_sha1_file(d->base.sha1, type, &size);
 605                if (!data)
 606                        continue;
 607                if      (!strcmp(type, blob_type))   obj_type = OBJ_BLOB;
 608                else if (!strcmp(type, tree_type))   obj_type = OBJ_TREE;
 609                else if (!strcmp(type, commit_type)) obj_type = OBJ_COMMIT;
 610                else if (!strcmp(type, tag_type))    obj_type = OBJ_TAG;
 611                else die("base object %s is of type '%s'",
 612                         sha1_to_hex(d->base.sha1), type);
 613
 614                find_delta_children(&d->base, &first, &last);
 615                for (j = first; j <= last; j++) {
 616                        struct object_entry *child = objects + deltas[j].obj_no;
 617                        if (child->real_type == OBJ_REF_DELTA)
 618                                resolve_delta(child, data, size, obj_type);
 619                }
 620
 621                append_obj_to_pack(data, size, obj_type);
 622                free(data);
 623                if (verbose)
 624                        percent = display_progress(nr_resolved_deltas,
 625                                                   nr_deltas, percent);
 626        }
 627        free(sorted_by_pos);
 628        if (verbose)
 629                fputc('\n', stderr);
 630}
 631
 632static void readjust_pack_header_and_sha1(unsigned char *sha1)
 633{
 634        struct pack_header hdr;
 635        SHA_CTX ctx;
 636        int size;
 637
 638        /* Rewrite pack header with updated object number */
 639        if (lseek(output_fd, 0, SEEK_SET) != 0)
 640                die("cannot seek back: %s", strerror(errno));
 641        if (read_in_full(output_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
 642                die("cannot read pack header back: %s", strerror(errno));
 643        hdr.hdr_entries = htonl(nr_objects);
 644        if (lseek(output_fd, 0, SEEK_SET) != 0)
 645                die("cannot seek back: %s", strerror(errno));
 646        write_or_die(output_fd, &hdr, sizeof(hdr));
 647        if (lseek(output_fd, 0, SEEK_SET) != 0)
 648                die("cannot seek back: %s", strerror(errno));
 649
 650        /* Recompute and store the new pack's SHA1 */
 651        SHA1_Init(&ctx);
 652        do {
 653                unsigned char *buf[4096];
 654                size = xread(output_fd, buf, sizeof(buf));
 655                if (size < 0)
 656                        die("cannot read pack data back: %s", strerror(errno));
 657                SHA1_Update(&ctx, buf, size);
 658        } while (size > 0);
 659        SHA1_Final(sha1, &ctx);
 660        write_or_die(output_fd, sha1, 20);
 661}
 662
 663static int sha1_compare(const void *_a, const void *_b)
 664{
 665        struct object_entry *a = *(struct object_entry **)_a;
 666        struct object_entry *b = *(struct object_entry **)_b;
 667        return hashcmp(a->sha1, b->sha1);
 668}
 669
 670/*
 671 * On entry *sha1 contains the pack content SHA1 hash, on exit it is
 672 * the SHA1 hash of sorted object names.
 673 */
 674static const char *write_index_file(const char *index_name, unsigned char *sha1)
 675{
 676        struct sha1file *f;
 677        struct object_entry **sorted_by_sha, **list, **last;
 678        unsigned int array[256];
 679        int i, fd;
 680        SHA_CTX ctx;
 681
 682        if (nr_objects) {
 683                sorted_by_sha =
 684                        xcalloc(nr_objects, sizeof(struct object_entry *));
 685                list = sorted_by_sha;
 686                last = sorted_by_sha + nr_objects;
 687                for (i = 0; i < nr_objects; ++i)
 688                        sorted_by_sha[i] = &objects[i];
 689                qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]),
 690                      sha1_compare);
 691
 692        }
 693        else
 694                sorted_by_sha = list = last = NULL;
 695
 696        if (!index_name) {
 697                static char tmpfile[PATH_MAX];
 698                snprintf(tmpfile, sizeof(tmpfile),
 699                         "%s/index_XXXXXX", get_object_directory());
 700                fd = mkstemp(tmpfile);
 701                index_name = xstrdup(tmpfile);
 702        } else {
 703                unlink(index_name);
 704                fd = open(index_name, O_CREAT|O_EXCL|O_WRONLY, 0600);
 705        }
 706        if (fd < 0)
 707                die("unable to create %s: %s", index_name, strerror(errno));
 708        f = sha1fd(fd, index_name);
 709
 710        /*
 711         * Write the first-level table (the list is sorted,
 712         * but we use a 256-entry lookup to be able to avoid
 713         * having to do eight extra binary search iterations).
 714         */
 715        for (i = 0; i < 256; i++) {
 716                struct object_entry **next = list;
 717                while (next < last) {
 718                        struct object_entry *obj = *next;
 719                        if (obj->sha1[0] != i)
 720                                break;
 721                        next++;
 722                }
 723                array[i] = htonl(next - sorted_by_sha);
 724                list = next;
 725        }
 726        sha1write(f, array, 256 * sizeof(int));
 727
 728        /* recompute the SHA1 hash of sorted object names.
 729         * currently pack-objects does not do this, but that
 730         * can be fixed.
 731         */
 732        SHA1_Init(&ctx);
 733        /*
 734         * Write the actual SHA1 entries..
 735         */
 736        list = sorted_by_sha;
 737        for (i = 0; i < nr_objects; i++) {
 738                struct object_entry *obj = *list++;
 739                unsigned int offset = htonl(obj->offset);
 740                sha1write(f, &offset, 4);
 741                sha1write(f, obj->sha1, 20);
 742                SHA1_Update(&ctx, obj->sha1, 20);
 743        }
 744        sha1write(f, sha1, 20);
 745        sha1close(f, NULL, 1);
 746        free(sorted_by_sha);
 747        SHA1_Final(sha1, &ctx);
 748        return index_name;
 749}
 750
 751static void final(const char *final_pack_name, const char *curr_pack_name,
 752                  const char *final_index_name, const char *curr_index_name,
 753                  const char *keep_name, const char *keep_msg,
 754                  unsigned char *sha1)
 755{
 756        char *report = "pack";
 757        char name[PATH_MAX];
 758        int err;
 759
 760        if (!from_stdin) {
 761                close(input_fd);
 762        } else {
 763                err = close(output_fd);
 764                if (err)
 765                        die("error while closing pack file: %s", strerror(errno));
 766                chmod(curr_pack_name, 0444);
 767        }
 768
 769        if (keep_msg) {
 770                int keep_fd, keep_msg_len = strlen(keep_msg);
 771                if (!keep_name) {
 772                        snprintf(name, sizeof(name), "%s/pack/pack-%s.keep",
 773                                 get_object_directory(), sha1_to_hex(sha1));
 774                        keep_name = name;
 775                }
 776                keep_fd = open(keep_name, O_RDWR|O_CREAT|O_EXCL, 0600);
 777                if (keep_fd < 0) {
 778                        if (errno != EEXIST)
 779                                die("cannot write keep file");
 780                } else {
 781                        if (keep_msg_len > 0) {
 782                                write_or_die(keep_fd, keep_msg, keep_msg_len);
 783                                write_or_die(keep_fd, "\n", 1);
 784                        }
 785                        close(keep_fd);
 786                        report = "keep";
 787                }
 788        }
 789
 790        if (final_pack_name != curr_pack_name) {
 791                if (!final_pack_name) {
 792                        snprintf(name, sizeof(name), "%s/pack/pack-%s.pack",
 793                                 get_object_directory(), sha1_to_hex(sha1));
 794                        final_pack_name = name;
 795                }
 796                if (move_temp_to_file(curr_pack_name, final_pack_name))
 797                        die("cannot store pack file");
 798        }
 799
 800        chmod(curr_index_name, 0444);
 801        if (final_index_name != curr_index_name) {
 802                if (!final_index_name) {
 803                        snprintf(name, sizeof(name), "%s/pack/pack-%s.idx",
 804                                 get_object_directory(), sha1_to_hex(sha1));
 805                        final_index_name = name;
 806                }
 807                if (move_temp_to_file(curr_index_name, final_index_name))
 808                        die("cannot store index file");
 809        }
 810
 811        if (!from_stdin) {
 812                printf("%s\n", sha1_to_hex(sha1));
 813        } else {
 814                char buf[48];
 815                int len = snprintf(buf, sizeof(buf), "%s\t%s\n",
 816                                   report, sha1_to_hex(sha1));
 817                write_or_die(1, buf, len);
 818
 819                /*
 820                 * Let's just mimic git-unpack-objects here and write
 821                 * the last part of the input buffer to stdout.
 822                 */
 823                while (input_len) {
 824                        err = xwrite(1, input_buffer + input_offset, input_len);
 825                        if (err <= 0)
 826                                break;
 827                        input_len -= err;
 828                        input_offset += err;
 829                }
 830        }
 831}
 832
 833int main(int argc, char **argv)
 834{
 835        int i, fix_thin_pack = 0;
 836        const char *curr_pack, *pack_name = NULL;
 837        const char *curr_index, *index_name = NULL;
 838        const char *keep_name = NULL, *keep_msg = NULL;
 839        char *index_name_buf = NULL, *keep_name_buf = NULL;
 840        unsigned char sha1[20];
 841
 842        for (i = 1; i < argc; i++) {
 843                const char *arg = argv[i];
 844
 845                if (*arg == '-') {
 846                        if (!strcmp(arg, "--stdin")) {
 847                                from_stdin = 1;
 848                        } else if (!strcmp(arg, "--fix-thin")) {
 849                                fix_thin_pack = 1;
 850                        } else if (!strcmp(arg, "--keep")) {
 851                                keep_msg = "";
 852                        } else if (!strncmp(arg, "--keep=", 7)) {
 853                                keep_msg = arg + 7;
 854                        } else if (!strncmp(arg, "--pack_header=", 14)) {
 855                                struct pack_header *hdr;
 856                                char *c;
 857
 858                                hdr = (struct pack_header *)input_buffer;
 859                                hdr->hdr_signature = htonl(PACK_SIGNATURE);
 860                                hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
 861                                if (*c != ',')
 862                                        die("bad %s", arg);
 863                                hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
 864                                if (*c)
 865                                        die("bad %s", arg);
 866                                input_len = sizeof(*hdr);
 867                        } else if (!strcmp(arg, "-v")) {
 868                                verbose = 1;
 869                        } else if (!strcmp(arg, "-o")) {
 870                                if (index_name || (i+1) >= argc)
 871                                        usage(index_pack_usage);
 872                                index_name = argv[++i];
 873                        } else
 874                                usage(index_pack_usage);
 875                        continue;
 876                }
 877
 878                if (pack_name)
 879                        usage(index_pack_usage);
 880                pack_name = arg;
 881        }
 882
 883        if (!pack_name && !from_stdin)
 884                usage(index_pack_usage);
 885        if (fix_thin_pack && !from_stdin)
 886                die("--fix-thin cannot be used without --stdin");
 887        if (!index_name && pack_name) {
 888                int len = strlen(pack_name);
 889                if (!has_extension(pack_name, ".pack"))
 890                        die("packfile name '%s' does not end with '.pack'",
 891                            pack_name);
 892                index_name_buf = xmalloc(len);
 893                memcpy(index_name_buf, pack_name, len - 5);
 894                strcpy(index_name_buf + len - 5, ".idx");
 895                index_name = index_name_buf;
 896        }
 897        if (keep_msg && !keep_name && pack_name) {
 898                int len = strlen(pack_name);
 899                if (!has_extension(pack_name, ".pack"))
 900                        die("packfile name '%s' does not end with '.pack'",
 901                            pack_name);
 902                keep_name_buf = xmalloc(len);
 903                memcpy(keep_name_buf, pack_name, len - 5);
 904                strcpy(keep_name_buf + len - 5, ".keep");
 905                keep_name = keep_name_buf;
 906        }
 907
 908        curr_pack = open_pack_file(pack_name);
 909        parse_pack_header();
 910        objects = xmalloc((nr_objects + 1) * sizeof(struct object_entry));
 911        deltas = xmalloc(nr_objects * sizeof(struct delta_entry));
 912        if (verbose)
 913                setup_progress_signal();
 914        parse_pack_objects(sha1);
 915        if (nr_deltas != nr_resolved_deltas) {
 916                if (fix_thin_pack) {
 917                        int nr_unresolved = nr_deltas - nr_resolved_deltas;
 918                        int nr_objects_initial = nr_objects;
 919                        if (nr_unresolved <= 0)
 920                                die("confusion beyond insanity");
 921                        objects = xrealloc(objects,
 922                                           (nr_objects + nr_unresolved + 1)
 923                                           * sizeof(*objects));
 924                        fix_unresolved_deltas(nr_unresolved);
 925                        if (verbose)
 926                                fprintf(stderr, "%d objects were added to complete this thin pack.\n",
 927                                        nr_objects - nr_objects_initial);
 928                        readjust_pack_header_and_sha1(sha1);
 929                }
 930                if (nr_deltas != nr_resolved_deltas)
 931                        die("pack has %d unresolved deltas",
 932                            nr_deltas - nr_resolved_deltas);
 933        } else {
 934                /* Flush remaining pack final 20-byte SHA1. */
 935                flush();
 936        }
 937        free(deltas);
 938        curr_index = write_index_file(index_name, sha1);
 939        final(pack_name, curr_pack,
 940                index_name, curr_index,
 941                keep_name, keep_msg,
 942                sha1);
 943        free(objects);
 944        free(index_name_buf);
 945        free(keep_name_buf);
 946
 947        return 0;
 948}