eSpeak synth driver: reset lastIndex to None when speech is canceldd.…

… Also move some code in the eSpeak callback so that if speech has been stopped the callback will return as soon as possible. This is partly to make sure that no last indexes accidentily get set after the last index was reset to None.

source/synthDrivers/_espeak.py

@@ -119,6 +119,8 @@ def __eq__(self, other):
 def callback(wav,numsamples,event):
 	try:
 		global player, isSpeaking, lastIndex
+		if not isSpeaking:
+			return 1
 		for e in event:
 			if e.type==espeakEVENT_MARK:
 				lastIndex=int(e.id.name)
@@ -128,8 +130,6 @@ def callback(wav,numsamples,event):
 			player.idle()
 			isSpeaking = False
 			return 0
-		if not isSpeaking:
-			return 1
 		if numsamples > 0:
 			try:
 				player.feed(string_at(wav, numsamples * sizeof(c_short)))
@@ -179,7 +179,7 @@ def speak(text):
 	_execWhenDone(_speak, text, mustBeAsync=True)
 
 def stop():
-	global isSpeaking, bgQueue
+	global isSpeaking, bgQueue, lastIndex
 	# Kill all speech from now.
 	# We still want parameter changes to occur, so requeue them.
 	params = []
@@ -196,6 +196,7 @@ def stop():
 		bgQueue.put(item)
 	isSpeaking = False
 	player.stop()
+	lastIndex=None
 
 def pause(switch):
 	global player