Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "object.h"
   3#include "delta.h"
   4#include "pack.h"
   5
   6#include <sys/time.h>
   7
   8static int dry_run, quiet;
   9static const char unpack_usage[] = "git-unpack-objects [-q] < pack-file";
  10
  11/* We always read in 4kB chunks. */
  12static unsigned char buffer[4096];
  13static unsigned long offset, len, eof;
  14static SHA_CTX ctx;
  15
  16/*
  17 * Make sure at least "min" bytes are available in the buffer, and
  18 * return the pointer to the buffer.
  19 */
  20static void * fill(int min)
  21{
  22        if (min <= len)
  23                return buffer + offset;
  24        if (eof)
  25                die("unable to fill input");
  26        if (min > sizeof(buffer))
  27                die("cannot fill %d bytes", min);
  28        if (offset) {
  29                SHA1_Update(&ctx, buffer, offset);
  30                memcpy(buffer, buffer + offset, len);
  31                offset = 0;
  32        }
  33        do {
  34                int ret = read(0, buffer + len, sizeof(buffer) - len);
  35                if (ret <= 0) {
  36                        if (!ret)
  37                                die("early EOF");
  38                        if (errno == EAGAIN || errno == EINTR)
  39                                continue;
  40                        die("read error on input: %s", strerror(errno));
  41                }
  42                len += ret;
  43        } while (len < min);
  44        return buffer;
  45}
  46
  47static void use(int bytes)
  48{
  49        if (bytes > len)
  50                die("used more bytes than were available");
  51        len -= bytes;
  52        offset += bytes;
  53}
  54
  55static void *get_data(unsigned long size)
  56{
  57        z_stream stream;
  58        void *buf = xmalloc(size);
  59
  60        memset(&stream, 0, sizeof(stream));
  61
  62        stream.next_out = buf;
  63        stream.avail_out = size;
  64        stream.next_in = fill(1);
  65        stream.avail_in = len;
  66        inflateInit(&stream);
  67
  68        for (;;) {
  69                int ret = inflate(&stream, 0);
  70                use(len - stream.avail_in);
  71                if (stream.total_out == size && ret == Z_STREAM_END)
  72                        break;
  73                if (ret != Z_OK)
  74                        die("inflate returned %d\n", ret);
  75                stream.next_in = fill(1);
  76                stream.avail_in = len;
  77        }
  78        inflateEnd(&stream);
  79        return buf;
  80}
  81
  82struct delta_info {
  83        unsigned char base_sha1[20];
  84        unsigned long size;
  85        void *delta;
  86        struct delta_info *next;
  87};
  88
  89static struct delta_info *delta_list;
  90
  91static void add_delta_to_list(unsigned char *base_sha1, void *delta, unsigned long size)
  92{
  93        struct delta_info *info = xmalloc(sizeof(*info));
  94
  95        memcpy(info->base_sha1, base_sha1, 20);
  96        info->size = size;
  97        info->delta = delta;
  98        info->next = delta_list;
  99        delta_list = info;
 100}
 101
 102static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size);
 103
 104static void write_object(void *buf, unsigned long size, const char *type)
 105{
 106        unsigned char sha1[20];
 107        if (write_sha1_file(buf, size, type, sha1) < 0)
 108                die("failed to write object");
 109        added_object(sha1, type, buf, size);
 110}
 111
 112static int resolve_delta(const char *type,
 113        void *base, unsigned long base_size, 
 114        void *delta, unsigned long delta_size)
 115{
 116        void *result;
 117        unsigned long result_size;
 118
 119        result = patch_delta(base, base_size,
 120                             delta, delta_size,
 121                             &result_size);
 122        if (!result)
 123                die("failed to apply delta");
 124        free(delta);
 125        write_object(result, result_size, type);
 126        free(result);
 127        return 0;
 128}
 129
 130static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size)
 131{
 132        struct delta_info **p = &delta_list;
 133        struct delta_info *info;
 134
 135        while ((info = *p) != NULL) {
 136                if (!memcmp(info->base_sha1, sha1, 20)) {
 137                        *p = info->next;
 138                        p = &delta_list;
 139                        resolve_delta(type, data, size, info->delta, info->size);
 140                        free(info);
 141                        continue;
 142                }
 143                p = &info->next;
 144        }
 145}
 146
 147static int unpack_non_delta_entry(enum object_type kind, unsigned long size)
 148{
 149        void *buf = get_data(size);
 150        const char *type;
 151
 152        switch (kind) {
 153        case OBJ_COMMIT: type = "commit"; break;
 154        case OBJ_TREE:   type = "tree"; break;
 155        case OBJ_BLOB:   type = "blob"; break;
 156        case OBJ_TAG:    type = "tag"; break;
 157        default: die("bad type %d", kind);
 158        }
 159        if (!dry_run)
 160                write_object(buf, size, type);
 161        free(buf);
 162        return 0;
 163}
 164
 165static int unpack_delta_entry(unsigned long delta_size)
 166{
 167        void *delta_data, *base;
 168        unsigned long base_size;
 169        char type[20];
 170        unsigned char base_sha1[20];
 171        int result;
 172
 173        memcpy(base_sha1, fill(20), 20);
 174        use(20);
 175
 176        delta_data = get_data(delta_size);
 177        if (dry_run) {
 178                free(delta_data);
 179                return 0;
 180        }
 181
 182        if (!has_sha1_file(base_sha1)) {
 183                add_delta_to_list(base_sha1, delta_data, delta_size);
 184                return 0;
 185        }
 186        base = read_sha1_file(base_sha1, type, &base_size);
 187        if (!base)
 188                die("failed to read delta-pack base object %s", sha1_to_hex(base_sha1));
 189        result = resolve_delta(type, base, base_size, delta_data, delta_size);
 190        free(base);
 191        return result;
 192}
 193
 194static void unpack_one(unsigned nr, unsigned total)
 195{
 196        unsigned shift;
 197        unsigned char *pack, c;
 198        unsigned long size;
 199        enum object_type type;
 200
 201        pack = fill(1);
 202        c = *pack;
 203        use(1);
 204        type = (c >> 4) & 7;
 205        size = (c & 15);
 206        shift = 4;
 207        while (c & 0x80) {
 208                pack = fill(1);
 209                c = *pack++;
 210                use(1);
 211                size += (c & 0x7f) << shift;
 212                shift += 7;
 213        }
 214        if (!quiet) {
 215                static unsigned long last_sec;
 216                static unsigned last_percent;
 217                struct timeval now;
 218                unsigned percentage = (nr * 100) / total;
 219
 220                gettimeofday(&now, NULL);
 221                if (percentage != last_percent || now.tv_sec != last_sec) {
 222                        last_sec = now.tv_sec;
 223                        last_percent = percentage;
 224                        fprintf(stderr, "%4u%% (%u/%u) done\r", percentage, nr, total);
 225                }
 226        }
 227        switch (type) {
 228        case OBJ_COMMIT:
 229        case OBJ_TREE:
 230        case OBJ_BLOB:
 231        case OBJ_TAG:
 232                unpack_non_delta_entry(type, size);
 233                return;
 234        case OBJ_DELTA:
 235                unpack_delta_entry(size);
 236                return;
 237        default:
 238                die("bad object type %d", type);
 239        }
 240}
 241
 242/*
 243 * We unpack from the end, older files first. Now, usually
 244 * there are deltas etc, so we'll not actually write the
 245 * objects in that order, but we might as well try..
 246 */
 247static void unpack_all(void)
 248{
 249        int i;
 250        struct pack_header *hdr = fill(sizeof(struct pack_header));
 251        unsigned version = ntohl(hdr->hdr_version);
 252        unsigned nr_objects = ntohl(hdr->hdr_entries);
 253
 254        if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
 255                die("bad pack file");
 256        if (version != PACK_VERSION)
 257                die("unable to handle pack file version %d", version);
 258        fprintf(stderr, "Unpacking %d objects\n", nr_objects);
 259
 260        use(sizeof(struct pack_header));
 261        for (i = 0; i < nr_objects; i++)
 262                unpack_one(i+1, nr_objects);
 263        if (delta_list)
 264                die("unresolved deltas left after unpacking");
 265}
 266
 267int main(int argc, char **argv)
 268{
 269        int i;
 270        unsigned char sha1[20];
 271
 272        for (i = 1 ; i < argc; i++) {
 273                const char *arg = argv[i];
 274
 275                if (*arg == '-') {
 276                        if (!strcmp(arg, "-n")) {
 277                                dry_run = 1;
 278                                continue;
 279                        }
 280                        if (!strcmp(arg, "-q")) {
 281                                quiet = 1;
 282                                continue;
 283                        }
 284                        usage(unpack_usage);
 285                }
 286
 287                /* We don't take any non-flag arguments now.. Maybe some day */
 288                usage(unpack_usage);
 289        }
 290        SHA1_Init(&ctx);
 291        unpack_all();
 292        SHA1_Update(&ctx, buffer, offset);
 293        SHA1_Final(sha1, &ctx);
 294        if (memcmp(fill(20), sha1, 20))
 295                die("final sha1 did not match");
 296        use(20);
 297
 298        /* Write the last part of the buffer to stdout */
 299        while (len) {
 300                int ret = write(1, buffer + offset, len);
 301                if (!ret)
 302                        break;
 303                if (ret < 0) {
 304                        if (errno == EAGAIN || errno == EINTR)
 305                                continue;
 306                        break;
 307                }
 308                len -= ret;
 309                offset += ret;
 310        }
 311
 312        /* All done */
 313        if (!quiet)
 314                fprintf(stderr, "\n");
 315        return 0;
 316}