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