Merge branch 'bc/object-id'

Conversion from uchar[20] to struct object_id continues.

* bc/object-id: (36 commits)
  convert: convert to struct object_id
  sha1_file: introduce a constant for max header length
  Convert lookup_replace_object to struct object_id
  sha1_file: convert read_sha1_file to struct object_id
  sha1_file: convert read_object_with_reference to object_id
  tree-walk: convert tree entry functions to object_id
  streaming: convert istream internals to struct object_id
  tree-walk: convert get_tree_entry_follow_symlinks internals to object_id
  builtin/notes: convert static functions to object_id
  builtin/fmt-merge-msg: convert remaining code to object_id
  sha1_file: convert sha1_object_info* to object_id
  Convert remaining callers of sha1_object_info_extended to object_id
  packfile: convert unpack_entry to struct object_id
  sha1_file: convert retry_bad_packed_offset to struct object_id
  sha1_file: convert assert_sha1_type to object_id
  builtin/mktree: convert to struct object_id
  streaming: convert open_istream to use struct object_id
  sha1_file: convert check_sha1_signature to struct object_id
  sha1_file: convert read_loose_object to use struct object_id
  builtin/index-pack: convert struct ref_delta_entry to object_id
  ...

rerere.c

@@ -979,8 +979,8 @@ static int handle_cache(const char *path, unsigned char *sha1, const char *outpu
 			break;
 		i = ce_stage(ce) - 1;
 		if (!mmfile[i].ptr) {
-			mmfile[i].ptr = read_sha1_file(ce->oid.hash, &type,
-						       &size);
+			mmfile[i].ptr = read_object_file(&ce->oid, &type,
+							 &size);
 			mmfile[i].size = size;
 		}
 	}