[PATCH] git-cat-file: '-s' to find out object size.

[git.git] / sha1_file.c

diff --git a/sha1_file.c b/sha1_file.c
index 7e4a3df3ad9f7be666256e3219651a5296da7aca..5695c962fe20a60940a5203bc3c33c0a201241e0 100644 (file)
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -601,9 +601,70 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l
        return unpack_sha1_rest(&stream, hdr, *size);
 }
 
-/* Returns 0 on fast-path success, returns 1 on deltified
- * and need to unpack to see info.
- */
+static int packed_delta_info(unsigned char *base_sha1,
+                            unsigned long delta_size,
+                            unsigned long left,
+                            char *type,
+                            unsigned long *sizep)
+{
+       unsigned char *data;
+       unsigned char delta_head[64];
+       int i;
+       unsigned char cmd;
+       unsigned long data_size, result_size, base_size, verify_base_size;
+       z_stream stream;
+       int st;
+
+       if (left < 20)
+               die("truncated pack file");
+       if (sha1_object_info(base_sha1, type, &base_size))
+               die("cannot get info for delta-pack base");
+
+       data = base_sha1 + 20;
+       data_size = left - 20;
+
+       memset(&stream, 0, sizeof(stream));
+
+       stream.next_in = data;
+       stream.avail_in = data_size;
+       stream.next_out = delta_head;
+       stream.avail_out = sizeof(delta_head);
+
+       inflateInit(&stream);
+       st = inflate(&stream, Z_FINISH);
+       inflateEnd(&stream);
+       if ((st != Z_STREAM_END) && stream.total_out != sizeof(delta_head))
+               die("delta data unpack-initial failed");
+
+       /* Examine the initial part of the delta to figure out
+        * the result size.  Verify the base size while we are at it.
+        */
+       data = delta_head;
+       verify_base_size = i = 0;
+       cmd = *data++;
+       while (cmd) {
+               if (cmd & 1)
+                       verify_base_size |= *data++ << i;
+               i += 8;
+               cmd >>= 1;
+       }
+
+       /* Read the result size */
+       result_size = i = 0;
+       cmd = *data++;
+       while (cmd) {
+               if (cmd & 1)
+                       result_size |= *data++ << i;
+               i += 8;
+               cmd >>= 1;
+       }
+       if (verify_base_size != base_size)
+               die("delta base size mismatch");
+
+       *sizep = result_size;
+       return 0;
+}
+
 static int packed_object_info(struct pack_entry *entry,
                              char *type, unsigned long *sizep)
 {
@@ -614,12 +675,16 @@ static int packed_object_info(struct pack_entry *entry,
        offset = entry->offset;
        if (p->pack_size - 5 < offset)
                die("object offset outside of pack file");
+
+       if (use_packed_git(p))
+               die("cannot map packed file");
+
        pack = p->pack_base + offset;
        size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4];
        left = p->pack_size - offset - 5;
        switch (*pack) {
        case 'D':
-               return 1;
+               return packed_delta_info(pack+5, size, left, type, sizep);
                break;
        case 'C':
                strcpy(type, "commit");
@@ -891,31 +956,46 @@ void *read_object_with_reference(const unsigned char *sha1,
        }
 }
 
+static char *write_sha1_file_prepare(void *buf,
+                                    unsigned long len,
+                                    const char *type,
+                                    unsigned char *sha1,
+                                    unsigned char *hdr,
+                                    int *hdrlen)
+{
+       SHA_CTX c;
+
+       /* Generate the header */
+       *hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
+
+       /* Sha1.. */
+       SHA1_Init(&c);
+       SHA1_Update(&c, hdr, *hdrlen);
+       SHA1_Update(&c, buf, len);
+       SHA1_Final(sha1, &c);
+
+       return sha1_file_name(sha1);
+}
+
 int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
 {
        int size;
        unsigned char *compressed;
        z_stream stream;
        unsigned char sha1[20];
-       SHA_CTX c;
        char *filename;
        static char tmpfile[PATH_MAX];
        unsigned char hdr[50];
        int fd, hdrlen, ret;
 
-       /* Generate the header */
-       hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
-
-       /* Sha1.. */
-       SHA1_Init(&c);
-       SHA1_Update(&c, hdr, hdrlen);
-       SHA1_Update(&c, buf, len);
-       SHA1_Final(sha1, &c);
-
+       /* Normally if we have it in the pack then we do not bother writing
+        * it out into .git/objects/??/?{38} file.
+        */
+       filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
        if (returnsha1)
                memcpy(returnsha1, sha1, 20);
-
-       filename = sha1_file_name(sha1);
+       if (has_sha1_file(sha1))
+               return 0;
        fd = open(filename, O_RDONLY);
        if (fd >= 0) {
                /*