[core/input] Add callback deregistration

Enable components to unregister callbacks (i.e. for dynamic widgets).

see #23

bumblebee/input.py

@@ -18,6 +18,7 @@ def read_input(inp):
         try:
             event = json.loads(line)
             inp.callback(event)
+            inp.redraw()
         except ValueError:
             pass
     inp.has_event = True
@@ -32,18 +33,28 @@ class I3BarInput(object):
         self.global_id = str(uuid.uuid4())
         self.need_event = False
         self.has_event = False
+        self._condition = threading.Condition()
 
     def start(self):
         """Start asynchronous input processing"""
         self.has_event = False
         self.running = True
+        self._condition.acquire()
         self._thread = threading.Thread(target=read_input, args=(self,))
         self._thread.start()
 
+    def redraw(self):
+        self._condition.acquire()
+        self._condition.notify()
+        self._condition.release()
+
     def alive(self):
         """Check whether the input processing is still active"""
         return self._thread.is_alive()
 
+    def wait(self, timeout):
+        self._condition.wait(timeout)
+
     def _wait(self):
         while not self.has_event:
             time.sleep(0.1)
@@ -51,18 +62,27 @@ class I3BarInput(object):
 
     def stop(self):
         """Stop asynchronous input processing"""
+        self._condition.release()
         if self.need_event:
             self._wait()
         self.running = False
         self._thread.join()
         return self.clean_exit
 
-    def register_callback(self, obj, button, cmd):
-        """Register a callback function or system call"""
+    def _uid(self, obj):
         uid = self.global_id
         if obj:
             uid = obj.id
+        return uid
 
+    def deregister_callbacks(self, obj):
+        uid = self._uid(obj)
+        if uid in self._callbacks:
+            del self._callbacks[uid]
+
+    def register_callback(self, obj, button, cmd):
+        """Register a callback function or system call"""
+        uid = self._uid(obj)
         if uid not in self._callbacks:
             self._callbacks[uid] = {}
         self._callbacks[uid][button] = cmd