merge-ort: add basic data structures for handling renames

This will grow later, but we only need a few fields for basic rename
handling.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge-ort.c

@@ -46,6 +46,25 @@ enum merge_side {
 	MERGE_SIDE2 = 2
 };
 
+struct rename_info {
+	/*
+	 * pairs: pairing of filenames from diffcore_rename()
+	 *
+	 * Index 1 and 2 correspond to sides 1 & 2 as used in
+	 * conflict_info.stages.  Index 0 unused.
+	 */
+	struct diff_queue_struct pairs[3];
+
+	/*
+	 * needed_limit: value needed for inexact rename detection to run
+	 *
+	 * If the current rename limit wasn't high enough for inexact
+	 * rename detection to run, this records the limit needed.  Otherwise,
+	 * this value remains 0.
+	 */
+	int needed_limit;
+};
+
 struct merge_options_internal {
 	/*
 	 * paths: primary data structure in all of merge ort.
@@ -113,6 +132,11 @@ struct merge_options_internal {
 	 */
 	struct strmap output;
 
+	/*
+	 * renames: various data relating to rename detection
+	 */
+	struct rename_info renames;
+
 	/*
 	 * current_dir_name: temporary var used in collect_merge_info_callback()
 	 *