Comments to indicate which locks guard which variables.

briar-core/src/org/briarproject/reliability/Receiver.java

@@ -21,15 +21,17 @@ class Receiver implements ReadHandler {
 
 	private final Clock clock;
 	private final Sender sender;
-	private final SortedSet<Data> dataFrames;
+	private final Lock windowLock = new ReentrantLock();
+	private final Condition dataFrameAvailable = windowLock.newCondition();
 
+	// The following are locking: windowLock
+	private final SortedSet<Data> dataFrames;
 	private int windowSize = MAX_WINDOW_SIZE;
+
 	private long finalSequenceNumber = Long.MAX_VALUE;
 	private long nextSequenceNumber = 1;
 
 	private volatile boolean valid = true;
-	private Lock synchLock = new ReentrantLock();
-	private Condition dataFrameAvailable = synchLock.newCondition();
 
 	Receiver(Clock clock, Sender sender) {
 		this.sender = sender;
@@ -38,7 +40,7 @@ class Receiver implements ReadHandler {
 	}
 
 	Data read() throws IOException, InterruptedException {
-		synchLock.lock();
+		windowLock.lock();
 		try {
 			long now = clock.currentTimeMillis(), end = now + READ_TIMEOUT;
 			while(now < end && valid) {
@@ -64,17 +66,17 @@ class Receiver implements ReadHandler {
 			if(valid) throw new IOException("Read timed out");
 			throw new IOException("Connection closed");
 		} finally {
-			synchLock.unlock();
+			windowLock.unlock();
 		}
 	}
 
 	void invalidate() {
 		valid = false;
-		synchLock.lock();
+		windowLock.lock();
 		try {
 			dataFrameAvailable.signalAll();
 		} finally {
-			synchLock.unlock();
+			windowLock.unlock();
 		}
 	}
 
@@ -95,7 +97,7 @@ class Receiver implements ReadHandler {
 	}
 
 	private void handleData(byte[] b) throws IOException {
-		synchLock.lock();
+		windowLock.lock();
 		try {
 			if(b.length < Data.MIN_LENGTH || b.length > Data.MAX_LENGTH) {
 				// Ignore data frame with invalid length
@@ -134,7 +136,7 @@ class Receiver implements ReadHandler {
 			// Acknowledge the data frame even if it's a duplicate
 			sender.sendAck(sequenceNumber, windowSize);
 		} finally {
-			synchLock.unlock();
+			windowLock.unlock();
 		}
 	}
 

briar-core/src/org/briarproject/reliability/Sender.java

@@ -26,8 +26,11 @@ class Sender {
 
 	private final Clock clock;
 	private final WriteHandler writeHandler;
-	private final LinkedList<Outstanding> outstanding;
+	private final Lock windowLock = new ReentrantLock();
+	private final Condition sendWindowAvailable = windowLock.newCondition();
 
+	// The following are locking: windowLock
+	private final LinkedList<Outstanding> outstanding;
 	private int outstandingBytes = 0;
 	private int windowSize = Data.MAX_PAYLOAD_LENGTH;
 	private int rtt = INITIAL_RTT, rttVar = INITIAL_RTT_VAR;
@@ -35,9 +38,6 @@ class Sender {
 	private long lastWindowUpdateOrProbe = Long.MAX_VALUE;
 	private boolean dataWaiting = false;
 
-	private Lock synchLock = new ReentrantLock();
-	private Condition sendWindowAvailable = synchLock.newCondition();
-
 	Sender(Clock clock, WriteHandler writeHandler) {
 		this.clock = clock;
 		this.writeHandler = writeHandler;
@@ -65,7 +65,7 @@ class Sender {
 		long sequenceNumber = a.getSequenceNumber();
 		long now = clock.currentTimeMillis();
 		Outstanding fastRetransmit = null;
-		synchLock.lock();
+		windowLock.lock();
 		try {
 			// Remove the acked data frame if it's outstanding
 			int foundIndex = -1;
@@ -105,7 +105,7 @@ class Sender {
 			if(windowSize > oldWindowSize || foundIndex != -1)
 				sendWindowAvailable.signalAll();
 		} finally {
-			synchLock.unlock();
+			windowLock.unlock();
 		}
 		// Fast retransmission
 		if(fastRetransmit != null)
@@ -116,7 +116,7 @@ class Sender {
 		long now = clock.currentTimeMillis();
 		List<Outstanding> retransmit = null;
 		boolean sendProbe = false;
-		synchLock.lock();
+		windowLock.lock();
 		try {
 			if(outstanding.isEmpty()) {
 				if(dataWaiting && now - lastWindowUpdateOrProbe > rto) {
@@ -147,7 +147,7 @@ class Sender {
 				}
 			}
 		} finally {
-			synchLock.unlock();
+			windowLock.unlock();
 		}
 		// Send a window probe if necessary
 		if(sendProbe) {
@@ -165,7 +165,7 @@ class Sender {
 
 	void write(Data d) throws IOException, InterruptedException {
 		int payloadLength = d.getPayloadLength();
-		synchLock.lock();
+		windowLock.lock();
 		try {
 			// Wait for space in the window
 			long now = clock.currentTimeMillis(), end = now + WRITE_TIMEOUT;
@@ -180,18 +180,18 @@ class Sender {
 			outstandingBytes += payloadLength;
 			dataWaiting = false;
 		} finally {
-			synchLock.unlock();
+			windowLock.unlock();
 		}
 		writeHandler.handleWrite(d.getBuffer());
 	}
 
 	void flush() throws IOException, InterruptedException {
-		synchLock.lock();
+		windowLock.lock();
 		try {
 			while(dataWaiting || !outstanding.isEmpty())
 				sendWindowAvailable.await();
 		} finally {
-			synchLock.unlock();
+			windowLock.unlock();
 		}
 	}