Optionally raise a timeout exception when waiting for the clipboard to change times out under context manager.

Author: gkuegler

dragonfly/windows/win32_clipboard.py

@@ -217,7 +217,7 @@ def wait_for_change(cls, timeout, step=0.001, formats=None,
     @classmethod
     @contextlib.contextmanager
     def synchronized_changes(cls, timeout, step=0.001, formats=None,
-                             initial_clipboard=None):
+                             initial_clipboard=None, raise_exception_on_timeout=False):
         seq_no = win32clipboard.GetClipboardSequenceNumber()
         if formats and not initial_clipboard:
             initial_clipboard = cls(from_system=True)
@@ -226,8 +226,9 @@ def synchronized_changes(cls, timeout, step=0.001, formats=None,
             yield
         finally:
             # Wait for the system clipboard to change.
-            cls._wait_for_change(timeout, step, formats, initial_clipboard,
-                                 seq_no)
+            if not cls._wait_for_change(timeout, step, formats, initial_clipboard,
+                                 seq_no) and raise_exception_on_timeout:
+                raise TimeoutError("Timed out waiting for clipboard to change.")
 
     #-----------------------------------------------------------------------