_UIAHandler

98 _com_interfaces_=[IUIAutomationEventHandler,IUIAutomationFocusChangedEventHandler,IUIAutomationPropertyChangedEventHandler] 99

100 - def __init__(self):

101 super(UIAHandler,self).__init__() 102 self.MTAThreadInitEvent=threading.Event() 103 self.MTAThreadStopEvent=threading.Event() 104 self.MTAThreadInitException=None 105 self.MTAThread=threading.Thread(target=self.MTAThreadFunc) 106 self.MTAThread.daemon=True 107 self.MTAThread.start() 108 self.MTAThreadInitEvent.wait(2) 109 if self.MTAThreadInitException: 110 raise self.MTAThreadInitException

111

112 - def terminate(self):

113 MTAThreadHandle=HANDLE(windll.kernel32.OpenThread(self.MTAThread.ident,False,winKernel.SYNCHRONIZE)) 114 self.MTAThreadStopEvent.set() 115 index=c_int() 116 #Wait for the MTAA thread to die (while still message pumping) 117 windll.user32.MsgWaitForMultipleObjects(1,byref(MTAThreadHandle),False,5000,0) 118 windll.kernel32.CloseHandle(MTAThreadHandle) 119 del self.MTAThread

120

121 - def MTAThreadFunc(self):

122 try: 123 oledll.ole32.CoInitializeEx(None,comtypes.COINIT_MULTITHREADED) 124 self.clientObject=CoCreateInstance(CUIAutomation._reg_clsid_,interface=IUIAutomation,clsctx=CLSCTX_INPROC_SERVER) 125 self.windowTreeWalker=self.clientObject.createTreeWalker(self.clientObject.CreateNotCondition(self.clientObject.CreatePropertyCondition(UIA_NativeWindowHandlePropertyId,0))) 126 self.windowCacheRequest=self.clientObject.CreateCacheRequest() 127 self.windowCacheRequest.AddProperty(UIA_NativeWindowHandlePropertyId) 128 self.UIAWindowHandleCache={} 129 self.baseTreeWalker=self.clientObject.RawViewWalker 130 self.baseCacheRequest=self.windowCacheRequest.Clone() 131 for propertyId in (UIA_ClassNamePropertyId,UIA_ControlTypePropertyId,UIA_IsKeyboardFocusablePropertyId,UIA_IsPasswordPropertyId,UIA_ProviderDescriptionPropertyId,UIA_ProcessIdPropertyId,UIA_IsSelectionItemPatternAvailablePropertyId,UIA_IsTextPatternAvailablePropertyId): 132 self.baseCacheRequest.addProperty(propertyId) 133 self.rootElement=self.clientObject.getRootElementBuildCache(self.baseCacheRequest) 134 self.reservedNotSupportedValue=self.clientObject.ReservedNotSupportedValue 135 self.clientObject.AddFocusChangedEventHandler(self.baseCacheRequest,self) 136 self.clientObject.AddPropertyChangedEventHandler(self.rootElement,TreeScope_Subtree,self.baseCacheRequest,self,UIAPropertyIdsToNVDAEventNames.keys()) 137 for x in UIAEventIdsToNVDAEventNames.iterkeys(): 138 self.clientObject.addAutomationEventHandler(x,self.rootElement,TreeScope_Subtree,self.baseCacheRequest,self) 139 except Exception as e: 140 self.MTAThreadInitException=e 141 finally: 142 self.MTAThreadInitEvent.set() 143 self.MTAThreadStopEvent.wait() 144 self.clientObject.RemoveAllEventHandlers()

145

146 - def IUIAutomationEventHandler_HandleAutomationEvent(self,sender,eventID):

147 if not self.MTAThreadInitEvent.isSet: 148 # UIAHandler hasn't finished initialising yet, so just ignore this event. 149 return 150 NVDAEventName=UIAEventIdsToNVDAEventNames.get(eventID,None) 151 if not NVDAEventName: 152 return 153 if not self.isNativeUIAElement(sender): 154 return 155 import NVDAObjects.UIA 156 obj=NVDAObjects.UIA.UIA(UIAElement=sender) 157 if not obj: 158 return 159 eventHandler.queueEvent(NVDAEventName,obj)

160

161 - def IUIAutomationFocusChangedEventHandler_HandleFocusChangedEvent(self,sender):

162 if not self.MTAThreadInitEvent.isSet: 163 # UIAHandler hasn't finished initialising yet, so just ignore this event. 164 return 165 if not self.isNativeUIAElement(sender): 166 return 167 try: 168 hasFocus=sender.currentHasKeyboardFocus 169 except COMError: 170 return 171 if not hasFocus: 172 return 173 import NVDAObjects.UIA 174 if isinstance(eventHandler.lastQueuedFocusObject,NVDAObjects.UIA.UIA): 175 lastFocus=eventHandler.lastQueuedFocusObject.UIAElement 176 # Ignore duplicate focus events. 177 # It seems that it is possible for compareElements to return True, even though the objects are different. 178 # Therefore, don't ignore the event if the last focus object has lost its hasKeyboardFocus state. 179 if self.clientObject.compareElements(sender,lastFocus) and lastFocus.currentHasKeyboardFocus: 180 return 181 obj=NVDAObjects.UIA.UIA(UIAElement=sender) 182 if not obj: 183 return 184 eventHandler.queueEvent("gainFocus",obj)

185

186 - def IUIAutomationPropertyChangedEventHandler_HandlePropertyChangedEvent(self,sender,propertyId,newValue):

187 if not self.MTAThreadInitEvent.isSet: 188 # UIAHandler hasn't finished initialising yet, so just ignore this event. 189 return 190 NVDAEventName=UIAPropertyIdsToNVDAEventNames.get(propertyId,None) 191 if not NVDAEventName: 192 return 193 if not self.isNativeUIAElement(sender): 194 return 195 import NVDAObjects.UIA 196 obj=NVDAObjects.UIA.UIA(UIAElement=sender) 197 if not obj: 198 return 199 eventHandler.queueEvent(NVDAEventName,obj)

200

201 - def isUIAWindow(self,hwnd):

202 now=time.time() 203 v=self.UIAWindowHandleCache.get(hwnd,None) 204 if not v or (now-v[1])>0.5: 205 if windll.kernel32.GetCurrentProcessId()==winUser.getWindowThreadProcessID(hwnd)[0]: 206 isUIA=False 207 elif winUser.getClassName(hwnd) in badUIAWindowClassNames: 208 isUIA=False 209 else: 210 isUIA=windll.UIAutomationCore.UiaHasServerSideProvider(hwnd) 211 self.UIAWindowHandleCache[hwnd]=(isUIA,now) 212 return isUIA 213 return v[0]

214

215 - def getNearestWindowHandle(self,UIAElement):

216 try: 217 UIAElement=self.windowTreeWalker.NormalizeElementBuildCache(UIAElement,self.windowCacheRequest) 218 except COMError: 219 return None 220 try: 221 return UIAElement.cachedNativeWindowHandle 222 except COMError: 223 return None

224

225 - def isNativeUIAElement(self,UIAElement):

226 #Due to issues dealing with UIA elements coming from the same process, we do not class these UIA elements as usable. 227 #It seems to be safe enough to retreave the cached processID, but using tree walkers or fetching other properties causes a freeze. 228 try: 229 processID=UIAElement.cachedProcessId 230 except COMError: 231 return False 232 if processID==windll.kernel32.GetCurrentProcessId(): 233 return False 234 #If the element has a window handle, whether it is a native element depends on whether the window natively supports UIA. 235 try: 236 windowHandle=UIAElement.cachedNativeWindowHandle 237 except COMError: 238 windowHandle=None 239 if windowHandle: 240 return self.isUIAWindow(windowHandle) 241 try: 242 providerDescription=UIAElement.cachedProviderDescription 243 except COMError: 244 return True 245 if re_MSAAProxyProviderDescription.search(providerDescription): 246 # This is an MSAA proxy. 247 # Whether this is a native element depends on whether the nearest window handle natively supports UIA. 248 windowHandle=self.getNearestWindowHandle(UIAElement) 249 if not windowHandle: 250 return False 251 return self.isUIAWindow(windowHandle) 252 return True

Source Code for Module _UIAHandler