sha1_file: introduce has_object_file helper.

Add has_object_file, which is a wrapper around has_sha1_file, but for
struct object_id.
Signed-off-by: Nbrian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: NJeff King <peff@peff.net>

cache.h

@@ -1030,6 +1030,9 @@ static inline int has_sha1_file(const unsigned char *sha1)
 	return has_sha1_file_with_flags(sha1, 0);
 }
 
+/* Same as the above, except for struct object_id. */
+extern int has_object_file(const struct object_id *oid);
+
 /*
  * Return true iff an alternate object database has a loose object
  * with the specified name.  This function does not respect replace

sha1_file.c

@@ -3216,6 +3216,11 @@ int has_sha1_file_with_flags(const unsigned char *sha1, int flags)
 	return find_pack_entry(sha1, &e);
 }
 
+int has_object_file(const struct object_id *oid)
+{
+	return has_sha1_file(oid->hash);
+}
+
 static void check_tree(const void *buf, size_t size)
 {
 	struct tree_desc desc;