Allow run_in_gui_thread to wait for the function to finish

blink/util.py

@@ -3,6 +3,9 @@ from PyQt4.QtCore import QObject, QThread, QTimer
 from PyQt4.QtGui import QApplication
 from application.python.decorator import decorator, preserve_signature
 from application.python.types import Singleton
+from functools import partial
+from threading import Event
+from sys import exc_info
 
 from blink.event import CallFunctionEvent
 
@@ -17,7 +20,7 @@ class QSingleton(Singleton, type(QObject)):
 def call_in_gui_thread(function, *args, **kw):
     application = QApplication.instance()
     if application.thread() is QThread.currentThread():
-        function(*args, **kw)
+        return function(*args, **kw)
     else:
         application.postEvent(application, CallFunctionEvent(function, args, kw))
 
@@ -26,15 +29,49 @@ def call_later(interval, function, *args, **kw):
     QTimer.singleShot(int(interval*1000), lambda: function(*args, **kw))
 
 
+class FunctionExecutor(object):
+    __slots__ = 'function', 'event', 'result', 'exception', 'traceback'
+
+    def __init__(self, function):
+        self.function = function
+        self.event = Event()
+        self.result = None
+        self.exception = None
+        self.traceback = None
+
+    def __call__(self, *args, **kw):
+        try:
+            self.result = self.function(*args, **kw)
+        except BaseException as exception:
+            self.exception = exception
+            self.traceback = exc_info()[2]
+        finally:
+            self.event.set()
+
+    def wait(self):
+        self.event.wait()
+        if self.exception is not None:
+            raise type(self.exception), self.exception, self.traceback
+        else:
+            return self.result
+
+
 @decorator
-def run_in_gui_thread(function):
+def run_in_gui_thread(function=None, wait=False):
+    if function is not None:
         @preserve_signature(function)
-    def wrapper(*args, **kw):
+        def function_wrapper(*args, **kw):
             application = QApplication.instance()
             if application.thread() is QThread.currentThread():
-            function(*args, **kw)
+                return function(*args, **kw)
+            else:
+                if wait:
+                    executor = FunctionExecutor(function)
+                    application.postEvent(application, CallFunctionEvent(executor, args, kw))
+                    return executor.wait()
                 else:
                     application.postEvent(application, CallFunctionEvent(function, args, kw))
-    return wrapper
-
+        return function_wrapper
+    else:
+        return partial(run_in_gui_thread, wait=wait)