Merge 7316138 into 9a4074b

michaelDCurran · web-flow · commit 07d6218bd8a1 · 2020-08-31T17:11:17.000+10:00
diff --git a/source/IAccessibleHandler/__init__.py b/source/IAccessibleHandler/__init__.py
@@ -4,6 +4,7 @@
 # This file is covered by the GNU General Public License.
 # See the file COPYING for more details.
 
+from typing import Tuple
 import struct
 import weakref
 # Kept for backwards compatibility
@@ -100,6 +101,12 @@
 	IA2_ROLE_MARK,
 )
 
+IAccessibleObjectIdentifierType = Tuple[
+	int,  # windowHandle
+	int,  # objectID
+	int,  # childID
+]
+
 from . import internalWinEventHandler
 # Imported for backwards compat
 from .internalWinEventHandler import (  # noqa: F401
@@ -126,8 +133,6 @@
 
 from .orderedWinEventLimiter import MENU_EVENTIDS
 
-MAX_WINEVENTS = 500
-
 # Special Mozilla gecko MSAA constant additions
 NAVRELATION_LABEL_FOR = 0x1002
 NAVRELATION_LABELLED_BY = 0x1003
@@ -857,9 +862,14 @@ def pumpAll():  # noqa: C901
 	fakeFocusEvent = None
 	focus = eventHandler.lastQueuedFocusObject
 
+	alwaysAllowedObjects = []
+	# winEvents for the currently focused object are special,
+	# and should be never filtered out.
+	if isinstance(focus, NVDAObjects.IAccessible.IAccessible) and focus.event_objectID is not None:
+		alwaysAllowedObjects.append((focus.event_windowHandle, focus.event_objectID, focus.event_childID))
+
 	# Receive all the winEvents from the limiter for this cycle
-	winEvents = winEventLimiter.flushEvents()
-	winEvents = winEvents[0 - MAX_WINEVENTS:]
+	winEvents = winEventLimiter.flushEvents(alwaysAllowedObjects)
 
 	for winEvent in winEvents:
 		isEventOnCaret = winEvent[2] == winUser.OBJID_CARET
diff --git a/source/IAccessibleHandler/orderedWinEventLimiter.py b/source/IAccessibleHandler/orderedWinEventLimiter.py
@@ -1,7 +1,10 @@
+from typing import Optional, List
 import heapq
 import itertools
 
 import winUser
+from . import IAccessibleObjectIdentifierType
+
 
 MAX_WINEVENTS_PER_THREAD = 10
 
@@ -75,10 +78,15 @@ def addEvent(
 		self._genericEventCache[(eventID, window, objectID, childID, threadID)] = next(self._eventCounter)
 		return True
 
-	def flushEvents(self):
+	def flushEvents(
+			self,
+			alwaysAllowedObjects: Optional[List[IAccessibleObjectIdentifierType]] = None
+	):
 		"""Returns a list of winEvents that have been added.
 		Due to limiting, it will not necessarily be all the winEvents that were originally added.
 		They are definitely guaranteed to be in the correct order though.
+		winEvents for objects listed in alwaysAllowedObjects will always be emitted,
+		Even if the winEvent limit for that thread has been exceeded.
 		@return Tuple[eventID,window,objectID,childID]
 		"""
 		if self._lastMenuEvent is not None:
@@ -88,11 +96,17 @@ def flushEvents(self):
 		self._genericEventCache = {}
 		threadCounters = {}
 		for k, v in sorted(g.items(), key=lambda item: item[1], reverse=True):
+			# Increase the event count for this thread by 1.
 			threadCount = threadCounters.get(k[-1], 0)
-			if threadCount > MAX_WINEVENTS_PER_THREAD:
+			threadCount += 1
+			threadCounters[k[-1]] = threadCount
+			# Find out if this event is for an object whos events are always allowed.
+			eventsForObjectAlwaysAllowed = alwaysAllowedObjects and k[1:-1] in alwaysAllowedObjects
+			if threadCount > MAX_WINEVENTS_PER_THREAD and not eventsForObjectAlwaysAllowed:
+				# Skip this event if too many events have already been emitted for this thread
+				# and this event is not for an object whos events are always allowed.
 				continue
 			heapq.heappush(self._eventHeap, (v,) + k)
-			threadCounters[k[-1]] = threadCount + 1
 		f = self._focusEventCache
 		self._focusEventCache = {}
 		for k, v in sorted(f.items(), key=lambda item: item[1])[0 - self.maxFocusItems:]:
