Merge fbd37d1 into c4ca763

source/braille.py

@@ -19,6 +19,7 @@
 	Tuple,
 	Union,
 	Type,
+	Callable,
 )
 from locale import strxfrm
 
@@ -53,6 +54,7 @@
 import re
 import scriptHandler
 import collections
+from collections import deque
 import extensionPoints
 import hwPortUtils
 import bdDetect
@@ -1569,6 +1571,7 @@ def bufferPosToRegionPos(self, bufferPos):
 		raise LookupError("No such position")
 
 	def regionPosToBufferPos(self, region, pos, allowNearest=False):
+		start: int = 0
 		for testRegion, start, end in self.regionsWithPositions:
 			if region == testRegion:
 				if pos < end - start:
@@ -2003,6 +2006,46 @@ def formatCellsForLog(cells: List[int]) -> str:
 """
 
 
+class RepeatedTimer:
+	"""Repeating timer.
+	Timer is used to try to ensure that display content is always up to date.
+	"""
+
+	def __init__(
+			self,
+			interval: float,
+			updateFunction: Callable[[], None]
+	):
+		"""Constructor.
+		@param interval: Checking frequency
+		@param updateFunction: Update display
+		"""
+		self._interval = interval
+		self._timer = threading.Timer(self._interval, self._run)
+		self._updateFunction = updateFunction
+		self.is_running = False
+		self.start()
+
+	def _run(self):
+		self.is_running = False
+		self.start()
+		self._updateFunction()
+
+	def start(self):
+		if not self.is_running:
+			self._timer = threading.Timer(self._interval, self._run)
+			self._timer.start()
+			self.is_running = True
+
+	def stop(self):
+		self._timer.cancel()
+		self.is_running = False
+
+
+UPDATE_DISPLAY_PERIODICALLY_INTERVAL: float = 0.5
+"""Timer interval for L{BrailleHandler._updateDisplayPeriodically}."""
+
+
 class BrailleHandler(baseObject.AutoPropertyObject):
 	# TETHER_AUTO, TETHER_FOCUS, TETHER_REVIEW and tetherValues
 	# are deprecated, but remain to retain API backwards compatibility
@@ -2042,6 +2085,13 @@ def __init__(self):
 		self._cursorPos = None
 		self._cursorBlinkUp = True
 		self._cells = []
+		self._oldCells: List[int] = []
+		self._handleUpdateQueue = deque(maxlen=1)
+		self._updateTimer = RepeatedTimer(
+			UPDATE_DISPLAY_PERIODICALLY_INTERVAL,
+			self._updateDisplayPeriodically
+		)
+		self._updateTimer.start()
 		self._cursorBlinkTimer = None
 		config.post_configProfileSwitch.register(self.handlePostConfigProfileSwitch)
 		if config.conf["braille"]["tetherTo"] == TetherTo.AUTO.value:
@@ -2064,6 +2114,9 @@ def terminate(self):
 		if self._cursorBlinkTimer:
 			self._cursorBlinkTimer.Stop()
 			self._cursorBlinkTimer = None
+		if self._updateTimer:
+			self._updateTimer.stop()
+			self._updateTimer = None
 		config.post_configProfileSwitch.unregister(self.handlePostConfigProfileSwitch)
 		if self.display:
 			self.display.terminate()
@@ -2468,6 +2521,12 @@ def handleCaretMove(
 		if shouldAutoTether:
 			self.setTether(TetherTo.FOCUS.value, auto=True)
 		if self._tether != TetherTo.FOCUS.value:
+			# Braille display content is updated in case where:
+			# braille is tethered to review, review cursor does not follow system caret,
+			# and focus object is navigator object.
+			if not config.conf["reviewCursor"]["followCaret"]:
+				if obj == api.getNavigatorObject():
+					self.handleUpdate(obj)
 			return
 		region = self.mainBuffer.regions[-1] if self.mainBuffer.regions else None
 		if region and region.obj==obj:
@@ -2526,7 +2585,7 @@ def _handleProgressBarUpdate(
 				self.handleUpdate(obj)
 				return
 
-	def handleUpdate(self, obj: "NVDAObject") -> None:
+	def handleUpdate(self, obj: "NVDAObject", fromTimer: bool = False) -> None:
 		if not self.enabled:
 			return
 		if objectBelowLockScreenAndWindowsIsLocked(obj):
@@ -2553,7 +2612,10 @@ def handleUpdate(self, obj: "NVDAObject") -> None:
 		self.mainBuffer.update()
 		self.mainBuffer.restoreWindow()
 		if self.buffer is self.mainBuffer:
+			if fromTimer and self._oldCells == self.buffer.windowBrailleCells:
+				return
 			self.update()
+			self._oldCells = self.buffer.windowBrailleCells.copy()
 		elif self.buffer is self.messageBuffer and keyboardHandler.keyCounter>self._keyCountForLastMessage:
 			self._dismissMessage()
 
@@ -2686,6 +2748,19 @@ def _ackTimeoutResetter(self, param: int):
 			self.display._awaitingAck = False
 			self._writeCellsInBackground()
 
+	def _updateDisplayPeriodically(self):
+		"""Timer runs this function periodically to ensure content is up to date."""
+		if self.buffer is not self.mainBuffer:
+			return
+		obj: NVDAObject
+		if api.isObjectInActiveTreeInterceptor(api.getNavigatorObject()):
+			obj = api.getCaretObject()
+		elif handler.getTether() == TetherTo.FOCUS.value:
+			obj = api.getFocusObject()
+		else:
+			obj = api.getNavigatorObject()
+		self._handleUpdateQueue.append(obj)
+
 
 # Maps old braille display driver names to new drivers that supersede old drivers.
 # Ensure that if a user has set a preferred driver which has changed name, the new
@@ -2720,14 +2795,17 @@ def initialize():
 	handler.setDisplayByName(config.conf["braille"]["display"])
 
 def pumpAll():
-	"""Runs tasks at the end of each core cycle. For now just caret updates."""
+	"""Runs tasks at the end of each core cycle."""
+	if len(handler._handleUpdateQueue):
+		handler.handleUpdate(handler._handleUpdateQueue.popleft(), True)
 	handler.handlePendingCaretUpdate()
 
 def terminate():
 	global handler
 	handler.terminate()
 	handler = None
 
+
 class BrailleDisplayDriver(driverHandler.Driver):
 	"""Abstract base braille display driver.
 	Each braille display driver should be a separate Python module in the root brailleDisplayDrivers directory