merge-ort: add new data structures for directory rename detection

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

diff --git a/merge-ort.c b/merge-ort.c
index d36a92b59b76fe49424ae97e4cd2777badb7e318..652ff730afa7d17f8b1dfa69220aa6caac486060 100644 (file)
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -49,14 +49,42 @@ enum merge_side {
 };
 
 struct rename_info {
+       /*
+        * All variables that are arrays of size 3 correspond to data tracked
+        * for the sides in enum merge_side.  Index 0 is almost always unused
+        * because we often only need to track information for MERGE_SIDE1 and
+        * MERGE_SIDE2 (MERGE_BASE can't have rename information since renames
+        * are determined relative to what changed since the MERGE_BASE).
+        */
+
        /*
         * 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];
 
+       /*
+        * dirs_removed: directories removed on a given side of history.
+        */
+       struct strset dirs_removed[3];
+
+       /*
+        * dir_rename_count: tracking where parts of a directory were renamed to
+        *
+        * When files in a directory are renamed, they may not all go to the
+        * same location.  Each strmap here tracks:
+        *      old_dir => {new_dir => int}
+        * That is, dir_rename_count[side] is a strmap to a strintmap.
+        */
+       struct strmap dir_rename_count[3];
+
+       /*
+        * dir_renames: computed directory renames
+        *
+        * This is a map of old_dir => new_dir and is derived in part from
+        * dir_rename_count.
+        */
+       struct strmap dir_renames[3];
+
        /*
         * needed_limit: value needed for inexact rename detection to run
         *