Andrew's git - gitweb.git/blob

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