Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "object.h"
   3
   4static int dry_run;
   5static int nr_entries;
   6static const char *base_name;
   7static const char unpack_usage[] = "git-unpack-objects basename";
   8
   9struct pack_entry {
  10        unsigned int offset;
  11        unsigned char sha1[20];
  12};
  13
  14static void *pack_base;
  15static unsigned long pack_size;
  16
  17static struct pack_entry **pack_list;
  18
  19static void *map_file(const char *suffix, unsigned long *sizep)
  20{
  21        static char pathname[PATH_MAX];
  22        unsigned long len;
  23        int fd;
  24        struct stat st;
  25        void *map;
  26
  27        len = snprintf(pathname, PATH_MAX, "%s.%s", base_name, suffix);
  28        if (len >= PATH_MAX)
  29                die("bad pack base-name");
  30        fd = open(pathname, O_RDONLY);
  31        if (fd < 0 || fstat(fd, &st))
  32                die("unable to open '%s'", pathname);
  33        len = st.st_size;
  34        if (!len)
  35                die("bad pack file '%s'", pathname);
  36        map = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
  37        if (-1 == (int)(long)map)
  38                die("unable to mmap '%s'", pathname);
  39        close(fd);
  40        *sizep = len;
  41        return map;
  42}
  43
  44static int sort_by_offset(const void *_a, const void *_b)
  45{
  46        struct pack_entry *a = *(struct pack_entry **)_a;
  47        struct pack_entry *b = *(struct pack_entry **)_b;
  48        unsigned int o1, o2;
  49
  50        o1 = ntohl(a->offset);
  51        o2 = ntohl(b->offset);
  52        return o1 < o2 ? -1 : 1;
  53}
  54
  55static int check_index(void *index, unsigned long idx_size)
  56{
  57        unsigned int *array = index;
  58        unsigned int nr;
  59        int i;
  60
  61        if (idx_size < 4*256)
  62                return error("index file too small");
  63        nr = 0;
  64        for (i = 0; i < 256; i++) {
  65                unsigned int n = ntohl(array[i]);
  66                if (n < nr)
  67                        return error("non-monotonic index");
  68                nr = n;
  69        }
  70        if (idx_size != 4*256 + nr * 24) {
  71                printf("idx_size=%lu, expected %u (%u)\n", idx_size, 4*256 + nr * 24, nr);
  72                return error("wrong index file size");
  73        }
  74
  75        nr_entries = nr;
  76        pack_list = xmalloc(nr * sizeof(struct pack_entry *));
  77        for (i = 0; i < nr; i++)
  78                pack_list[i] = index + 4*256 + i*24;
  79
  80        qsort(pack_list, nr, sizeof(*pack_list), sort_by_offset);
  81
  82        printf("%d entries\n", nr);
  83        return 0;
  84}
  85
  86static void unpack_entry(struct pack_entry *entry)
  87{
  88        unsigned long size;
  89        unsigned long offset;
  90        unsigned char *pack;
  91
  92        /* Have we done this one already due to deltas based on it? */
  93        if (lookup_object(entry->sha1))
  94                return;
  95
  96        offset = ntohl(entry->offset);
  97        if (offset > pack_size - 5)
  98                die("object offset outside of pack file");
  99        pack = pack_base + offset;
 100        offset = pack_size - offset;
 101        switch (*pack) {
 102        case 'C': case 'T': case 'B':
 103                size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4];
 104                printf("%s %c %lu\n", sha1_to_hex(entry->sha1), *pack, size);
 105                break;
 106        case 'D':
 107                printf("%s D", sha1_to_hex(entry->sha1));
 108                printf(" %s\n", sha1_to_hex(pack+1));
 109                break;
 110        default:
 111                die("corrupted pack file");
 112        }
 113}
 114
 115/*
 116 * We unpack from the end, older files first. Now, usually
 117 * there are deltas etc, so we'll not actually write the
 118 * objects in that order, but we might as well try..
 119 */
 120static void unpack_all(void)
 121{
 122        int i = nr_entries;
 123
 124        while (--i >= 0) {
 125                struct pack_entry *entry = pack_list[i];
 126                unpack_entry(entry);
 127        }
 128}
 129
 130int main(int argc, char **argv)
 131{
 132        int i;
 133        unsigned long idx_size;
 134        void *index;
 135
 136        for (i = 1 ; i < argc; i++) {
 137                const char *arg = argv[i];
 138
 139                if (*arg == '-') {
 140                        if (!strcmp(arg, "-n")) {
 141                                dry_run = 1;
 142                                continue;
 143                        }
 144                        usage(unpack_usage);
 145                }
 146                if (base_name)
 147                        usage(unpack_usage);
 148                base_name = arg;
 149        }
 150        if (!base_name)
 151                usage(unpack_usage);
 152        index = map_file("idx", &idx_size);
 153        pack_base = map_file("pack", &pack_size);
 154        if (check_index(index, idx_size) < 0)
 155                die("bad index file");
 156        unpack_all();
 157        return 0;
 158}