bitbake: event: Always use threadlock

With the move to a server idle thread, we always need threading. The
existing accessor functions could end up turning this off!

I was going to hold the lock whilst changing it, check if the value
was already set, cache the result and also fix the event code to always
release the lock with a try/finally.

Instead, disable the existing functions and use a with: block
to handle the lock, keeping things much simpler.

(Bitbake rev: 645c9d3b50e55f69b222cc338373cdfd91d524ce)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/event.py

@@ -68,16 +68,15 @@ _catchall_handlers = {}
 _eventfilter = None
 _uiready = False
 _thread_lock = threading.Lock()
-_thread_lock_enabled = False
 _heartbeat_enabled = False
 
 def enable_threadlock():
-    global _thread_lock_enabled
-    _thread_lock_enabled = True
+    # Always needed now
+    return
 
 def disable_threadlock():
-    global _thread_lock_enabled
-    _thread_lock_enabled = False
+    # Always needed now
+    return
 
 def enable_heartbeat():
     global _heartbeat_enabled
@@ -179,36 +178,30 @@ def print_ui_queue():
 
 def fire_ui_handlers(event, d):
     global _thread_lock
-    global _thread_lock_enabled
 
     if not _uiready:
         # No UI handlers registered yet, queue up the messages
         ui_queue.append(event)
         return
 
-    if _thread_lock_enabled:
-        _thread_lock.acquire()
-
-    errors = []
-    for h in _ui_handlers:
-        #print "Sending event %s" % event
-        try:
-             if not _ui_logfilters[h].filter(event):
-                 continue
-             # We use pickle here since it better handles object instances
-             # which xmlrpc's marshaller does not. Events *must* be serializable
-             # by pickle.
-             if hasattr(_ui_handlers[h].event, "sendpickle"):
-                _ui_handlers[h].event.sendpickle((pickle.dumps(event)))
-             else:
-                _ui_handlers[h].event.send(event)
-        except:
-            errors.append(h)
-    for h in errors:
-        del _ui_handlers[h]
-
-    if _thread_lock_enabled:
-        _thread_lock.release()
+    with _thread_lock:
+        errors = []
+        for h in _ui_handlers:
+            #print "Sending event %s" % event
+            try:
+                 if not _ui_logfilters[h].filter(event):
+                     continue
+                 # We use pickle here since it better handles object instances
+                 # which xmlrpc's marshaller does not. Events *must* be serializable
+                 # by pickle.
+                 if hasattr(_ui_handlers[h].event, "sendpickle"):
+                    _ui_handlers[h].event.sendpickle((pickle.dumps(event)))
+                 else:
+                    _ui_handlers[h].event.send(event)
+            except:
+                errors.append(h)
+        for h in errors:
+            del _ui_handlers[h]
 
 def fire(event, d):
     """Fire off an Event"""
@@ -322,21 +315,23 @@ def set_eventfilter(func):
     _eventfilter = func
 
 def register_UIHhandler(handler, mainui=False):
-    bb.event._ui_handler_seq = bb.event._ui_handler_seq + 1
-    _ui_handlers[_ui_handler_seq] = handler
-    level, debug_domains = bb.msg.constructLogOptions()
-    _ui_logfilters[_ui_handler_seq] = UIEventFilter(level, debug_domains)
-    if mainui:
-        global _uiready
-        _uiready = _ui_handler_seq
-    return _ui_handler_seq
+    with _thread_lock:
+        bb.event._ui_handler_seq = bb.event._ui_handler_seq + 1
+        _ui_handlers[_ui_handler_seq] = handler
+        level, debug_domains = bb.msg.constructLogOptions()
+        _ui_logfilters[_ui_handler_seq] = UIEventFilter(level, debug_domains)
+        if mainui:
+            global _uiready
+            _uiready = _ui_handler_seq
+        return _ui_handler_seq
 
 def unregister_UIHhandler(handlerNum, mainui=False):
     if mainui:
         global _uiready
         _uiready = False
-    if handlerNum in _ui_handlers:
-        del _ui_handlers[handlerNum]
+    with _thread_lock:
+        if handlerNum in _ui_handlers:
+            del _ui_handlers[handlerNum]
     return
 
 def get_uihandler():

bitbake/lib/bb/tests/event.py

@@ -451,10 +451,9 @@ class EventHandlingTest(unittest.TestCase):
             and disable threadlocks tests """
         bb.event.fire(bb.event.OperationStarted(), None)
 
-    def test_enable_threadlock(self):
+    def test_event_threadlock(self):
         """ Test enable_threadlock method """
         self._set_threadlock_test_mockups()
-        bb.event.enable_threadlock()
         self._set_and_run_threadlock_test_workers()
         # Calls to UI handlers should be in order as all the registered
         # handlers for the event coming from the first worker should be
@@ -462,20 +461,6 @@ class EventHandlingTest(unittest.TestCase):
         self.assertEqual(self._threadlock_test_calls,
                          ["w1_ui1", "w1_ui2", "w2_ui1", "w2_ui2"])
 
-
-    def test_disable_threadlock(self):
-        """ Test disable_threadlock method """
-        self._set_threadlock_test_mockups()
-        bb.event.disable_threadlock()
-        self._set_and_run_threadlock_test_workers()
-        # Calls to UI handlers should be intertwined together. Thanks to the
-        # delay in the registered handlers for the event coming from the first
-        # worker, the event coming from the second worker starts being
-        # processed before finishing handling the first worker event.
-        self.assertEqual(self._threadlock_test_calls,
-                         ["w1_ui1", "w2_ui1", "w1_ui2", "w2_ui2"])
-
-
 class EventClassesTest(unittest.TestCase):
     """ Event classes test class """