blob: add repository argument to lookup_blob

Add a repository argument to allow the callers of lookup_blob
to be more specific about which repository to act on. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

blob.h

@@ -9,7 +9,8 @@ struct blob {
 	struct object object;
 };
 
-struct blob *lookup_blob(const struct object_id *oid);
+#define lookup_blob(r, o) lookup_blob_##r(o)
+struct blob *lookup_blob_the_repository(const struct object_id *oid);
 
 int parse_blob_buffer(struct blob *item, void *buffer, unsigned long size);