Make update code on playing a stone much more efficient

lib/goban.py

@@ -67,19 +67,33 @@ class Goban:
         self.hover = None
         
 
+    # For performance reasons (to help with drawing code)
+    # any modified positions are returned in a list.
+    # This is self._changed, which is modified by this
+    # function and by _delete_group_r().
+    # This list will *also* contain the last move and any
+    # previous or new ko positions.
     def play_move(self, pos, color=None):
         if color is None:
             color = self.to_move
 
         if self.to_move == Goban.EMPTY:
-            return
+            return None
 
         rpos = self._real_pos(pos)
         
         if not self._valid_move(rpos, color):
-            return
+            return None
 
         self.board[rpos] = color
+        self._changed = []
+        self._changed.append(rpos)
+
+        if self.ko is not None:
+            self._changed.append(self.ko)
+        if self.last_move is not None:
+            self._changed.append(self.last_move)
+
         self._capture(rpos)
         self.last_move = rpos
         self.passed_last = False
@@ -87,6 +101,12 @@ class Goban:
         self.to_move = self._other_color(color)
         self.clear_hover()
 
+        # If there is a new ko, send that back too
+        if self.ko is not None:
+            self._changed.append(self.ko)
+
+        return self._changed
+
 
 
     # fixme: need to handle post-game stuff here... scoring code
@@ -94,6 +114,12 @@ class Goban:
         if color is None:
             color = self.to_move
 
+        self._changed = []
+        if self.ko is not None:
+            self._changed.append(self.ko)
+        if self.last_move is not None:
+            self._changed.append(self.last_move)
+
         if self.passed_last:
             self.to_move = Goban.EMPTY
         else:
@@ -103,17 +129,27 @@ class Goban:
         self.last_move = None
         self.ko = None
 
+        return self._changed
+
 
     def resign(self, color=None):
         if color is None:
             color = self.to_move
 
+        self._changed = []
+        if self.ko is not None:
+            self._changed.append(self.ko)
+        if self.last_move is not None:
+            self._changed.append(self.last_move)
+
         self.passed_last = False
         self.last_move = None
         self.ko = None
         self.winner = self._other_color(color)
         self.to_move = Goban.EMPTY
 
+        return self._changed
+
 
     def _capture(self, pos, color=None):
         """Look for stones captured on the 4 sides of pos, remove them and increment
@@ -232,12 +268,6 @@ class Goban:
 
         return self._delete_group_r(pos, who)
 
-        if who == Goban.EMPTY:
-            return 0
-
-        self.board[x][y].state = Goban.EMPTY
-
-
 
     def _delete_group_r(self, pos, who):
         if not self._on_board(pos):
@@ -247,6 +277,7 @@ class Goban:
             return 0
 
         self.board[pos] = Goban.EMPTY
+        self._changed.append(pos)
 
         num_deleted = 1