Support UI Automation within a Windows Defender Application Guard process

source/NVDAObjects/UIA/__init__.py

@@ -817,8 +817,6 @@ def __init__(self,windowHandle=None,UIAElement=None,initialUIACachedPropertyIDs=
 
 		UIACachedWindowHandle=UIAElement.cachedNativeWindowHandle
 		self.UIAIsWindowElement=bool(UIACachedWindowHandle)
-		if UIACachedWindowHandle:
-			windowHandle=UIACachedWindowHandle
 		if not windowHandle:
 			windowHandle=UIAHandler.handler.getNearestWindowHandle(UIAElement)
 		if not windowHandle:
@@ -1136,7 +1134,7 @@ def _get_children(self):
 			return children
 		for index in xrange(cachedChildren.length):
 			e=cachedChildren.getElement(index)
-			windowHandle=e.cachedNativeWindowHandle or self.windowHandle
+			windowHandle=self.windowHandle
 			children.append(self.correctAPIForRelation(UIA(windowHandle=windowHandle,UIAElement=e)))
 		return children
 

source/_UIAHandler.py

@@ -21,6 +21,7 @@
 import winUser
 import eventHandler
 from logHandler import log
+import UIAUtils
 
 from comtypes.gen.UIAutomationClient import *
 
@@ -45,7 +46,10 @@
 HorizontalTextAlignment_Centered=1
 HorizontalTextAlignment_Right=2
 HorizontalTextAlignment_Justified=3
-
+
+# The name of the WDAG (Windows Defender Application Guard) process
+WDAG_PROCESS_NAME=u'hvsirdpclient'
+
 badUIAWindowClassNames=[
 	"SysTreeView32",
 	"WuDuiListView",
@@ -291,6 +295,9 @@ def _isUIAWindowHelper(self,hwnd):
 			return False
 		import NVDAObjects.window
 		windowClass=NVDAObjects.window.Window.normalizeWindowClassName(winUser.getClassName(hwnd))
+		# A WDAG (Windows Defender Application Guard) Window is always native UIA, even if it doesn't report as such.
+		if windowClass=='RAIL_WINDOW':
+			return True
 		# There are certain window classes that just had bad UIA implementations
 		if windowClass in badUIAWindowClassNames:
 			return False
@@ -320,19 +327,26 @@ def getNearestWindowHandle(self,UIAElement):
 			# Called previously. Use cached result.
 			return UIAElement._nearestWindowHandle
 		try:
-			window=UIAElement.cachedNativeWindowHandle
+			processID=UIAElement.cachedProcessID
+		except COMError:
+			return None
+		appModule=appModuleHandler.getAppModuleFromProcessID(processID)
+		# WDAG (Windows Defender application Guard) UIA elements should be treated as being from a remote machine, and therefore their window handles are completely invalid on this machine.
+		# Therefore, jump all the way up to the root of the WDAG process and use that window handle as it is local to this machine.
+		if appModule.appName==WDAG_PROCESS_NAME:
+			condition=UIAUtils.createUIAMultiPropertyCondition({UIA_ClassNamePropertyId:[u'ApplicationFrameWindow',u'CabinetWClass']})
+			walker=self.clientObject.createTreeWalker(condition)
+		else:
+			# Not WDAG, just walk up to the nearest valid windowHandle
+			walker=self.windowTreeWalker
+		try:
+			new=walker.NormalizeElementBuildCache(UIAElement,self.windowCacheRequest)
+		except COMError:
+			return None
+		try:
+			window=new.cachedNativeWindowHandle
 		except COMError:
 			window=None
-		if not window:
-			# This element reports no window handle, so use the nearest ancestor window handle.
-			try:
-				new=self.windowTreeWalker.NormalizeElementBuildCache(UIAElement,self.windowCacheRequest)
-			except COMError:
-				return None
-			try:
-				window=new.cachedNativeWindowHandle
-			except COMError:
-				window=None
 		# Cache for future use to improve performance.
 		UIAElement._nearestWindowHandle=window
 		return window