Merge "logd: correct duplicate message state machine" (9fa0215e) · Commits · e / os / android_system_core

logd/LogBuffer.cpp

+70 −6

Original line number	Diff line number	Diff line
		@@ -206,6 +206,68 @@ int LogBuffer::log(log_id_t log_id, log_time realtime,
		if (currentLast) {
		LogBufferElement *dropped = droppedElements[log_id];
		unsigned short count = dropped ? dropped->getDropped() : 0;
		//
		// State Init
		// incoming:
		// dropped = NULL
		// currentLast = NULL;
		// elem = incoming message
		// outgoing:
		// dropped = NULL -> State 0
		// currentLast = copy of elem
		// log elem
		// State 0
		// incoming:
		// count = 0
		// dropped = NULL
		// currentLast = copy of last message
		// elem = incoming message
		// outgoing: (if elem == currentLast)
		// dropped = copy of first identical message -> State 1
		// currentLast = reference to elem
		// break: (if elem != currentLast)
		// dropped = NULL -> State 0
		// delete copy of last message (incoming currentLast)
		// currentLast = copy of elem
		// log elem
		// State 1
		// incoming:
		// count = 0
		// dropped = copy of first identical message
		// currentLast = reference to last held-back incoming
		// message
		// elem = incoming message
		// outgoing: (if elem == currentLast)
		// delete copy of first identical message (dropped)
		// dropped = reference to last held-back incoming
		// message set to chatty count of 1 -> State 2
		// currentLast = reference to elem
		// break:
		// delete dropped
		// dropped = NULL -> State 0
		// log reference to last held-back (currentLast)
		// currentLast = copy of elem
		// log elem
		// State 2
		// incoming:
		// count = chatty count
		// dropped = chatty message holding count
		// currentLast = reference to last held-back incoming
		// message.
		// dropped = chatty message holding count
		// elem = incoming message
		// outgoing: (if elem == currentLast)
		// delete chatty message holding count
		// dropped = reference to last held-back incoming
		// message, set to chatty count + 1
		// currentLast = reference to elem
		// break:
		// log dropped (chatty message)
		// dropped = NULL -> State 0
		// log reference to last held-back (currentLast)
		// currentLast = copy of elem
		// log elem
		//
		if (identical(elem, currentLast)) {
		if (dropped) {
		if (count == USHRT_MAX) {
		@@ -226,13 +288,15 @@ int LogBuffer::log(log_id_t log_id, log_time realtime,
		pthread_mutex_unlock(&mLogElementsLock);
		return len;
		}
		if (dropped) {
		log(dropped);
		droppedElements[log_id] = NULL;
		if (dropped) { // State 1 or 2
		if (count) { // State 2
		log(dropped); // report chatty
		} else { // State 1
		delete dropped;
		}
		if (count) {
		log(currentLast);
		} else {
		droppedElements[log_id] = NULL;
		log(currentLast); // report last message in the series
		} else { // State 0
		delete currentLast;
		}
		}