[meld] tree: Move previous/next path finding logic to SearchableTreeStore

[Kai Willadsen <kaiw src gnome org>]

commit bf9d0903f4619830f228c3b0b1bfb1763a318d0e
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Oct 23 07:43:05 2016 +1000

    tree: Move previous/next path finding logic to SearchableTreeStore

 meld/tree.py | 43 ++++++++++++++++++++++++-------------------
 1 file changed, 24 insertions(+), 19 deletions(-)
---
diff --git a/meld/tree.py b/meld/tree.py
index 1706d5c3..bf39748d 100644
--- a/meld/tree.py
+++ b/meld/tree.py
@@ -78,6 +78,26 @@ class SearchableTreeStore(Gtk.TreeStore):
                     raise StopIteration()
             yield it
 
+    def get_previous_next_paths(self, path, match_func):
+        prev_path, next_path = None, None
+        try:
+            start_iter = self.get_iter(path)
+        except ValueError:
+            # Invalid tree path
+            return None, None
+
+        for it in self.inorder_search_up(start_iter):
+            if match_func(it):
+                prev_path = self.get_path(it)
+                break
+
+        for it in self.inorder_search_down(start_iter):
+            if match_func(it):
+                next_path = self.get_path(it)
+                break
+
+        return prev_path, next_path
+
 
 class DiffTreeStore(SearchableTreeStore):
 
@@ -207,26 +227,11 @@ class DiffTreeStore(SearchableTreeStore):
             return None
 
     def _find_next_prev_diff(self, start_path):
-        prev_path, next_path = None, None
-        try:
-            start_iter = self.get_iter(start_path)
-        except ValueError:
-            # Invalid tree path
-            return None, None
-
-        for it in self.inorder_search_up(start_iter):
-            state = self.get_state(it, 0)
-            if state not in (STATE_NORMAL, STATE_EMPTY):
-                prev_path = self.get_path(it)
-                break
-
-        for it in self.inorder_search_down(start_iter):
-            state = self.get_state(it, 0)
-            if state not in (STATE_NORMAL, STATE_EMPTY):
-                next_path = self.get_path(it)
-                break
+        def match_func(it):
+            # TODO: It works, but matching on the first pane only is very poor
+            return self.get_state(it, 0) not in (STATE_NORMAL, STATE_EMPTY)
 
-        return prev_path, next_path
+        return self.get_previous_next_paths(start_path, match_func)
 
     def state_rows(self, states):
         """Generator of rows in one of the given states