[PATCH] Obtain sha1_file_info() for deltified pack entry properly.
The initial one was not doing enough to figure things out
without uncompressing too much. It also fixes a potential
segfault resulting from missing use_packed_git() call.
We would need to introduce unuse_packed_git() call and do proper
use counting to figure out when it is safe to unmap, but
currently we do not unmap packed file yet.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/sha1_file.c b/sha1_file.c
index 698b43c..5695c96 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -601,9 +601,70 @@
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 @@
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");
