Generate a unique cid for each (event_type, func) pair.

Author: mdboom

lib/matplotlib/cbook.py

@@ -243,22 +243,21 @@ def __init__(self, *args):
                 DeprecationWarning)
         self.callbacks = dict()
         self._cid = 0
-        self._func_cid_map = WeakKeyDictionary()
+        self._func_cid_map = {}
 
     def connect(self, s, func):
         """
         register *func* to be called when a signal *s* is generated
         func will be called
         """
-        if func in self._func_cid_map:
-            cid = self._func_cid_map[func]
-        else:
-            self._cid += 1
-            cid = self._cid
-            self._func_cid_map[func] = cid
+        self._func_cid_map.setdefault(s, WeakKeyDictionary())
+        if func in self._func_cid_map[s]:
+            return self._func_cid_map[s][func]
+
+        self._cid += 1
+        cid = self._cid
+        self._func_cid_map[s][func] = cid
         self.callbacks.setdefault(s, dict())
-        if cid in self.callbacks[s]:
-            return cid
         proxy = self.BoundMethodProxy(func)
         self.callbacks[s][cid] = proxy
         return cid
@@ -272,6 +271,8 @@ def disconnect(self, cid):
                 del callbackd[cid]
             except KeyError:
                 continue
+            else:
+                return
 
     def process(self, s, *args, **kwargs):
         """