Read the tag on a connection recogniser thread, don't block the

plugin.

api/net/sf/briar/api/ExceptionHandler.java

@@ -1,6 +0,0 @@
-package net.sf.briar.api;
-
-public interface ExceptionHandler<E extends Exception> {
-
-	void handleException(E exception);
-}

api/net/sf/briar/api/transport/ConnectionRecogniser.java

@@ -1,6 +1,5 @@
 package net.sf.briar.api.transport;
 
-import net.sf.briar.api.ExceptionHandler;
 import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.protocol.TransportId;
 
@@ -11,15 +10,9 @@ import net.sf.briar.api.protocol.TransportId;
 public interface ConnectionRecogniser {
 
 	/**
-	 * Asynchronously calls one of the callback's connectionAccepted(),
-	 * connectionRejected() or handleException() methods.
+	 * Returns the context for the given connection if the connection was
+	 * expected, or null if the connection was not expected.
 	 */
-	void acceptConnection(TransportId t, byte[] tag, Callback c);
-
-	interface Callback extends ExceptionHandler<DbException> {
-
-		void connectionAccepted(ConnectionContext ctx);
-
-		void connectionRejected();
-	}
+	ConnectionContext acceptConnection(TransportId t, byte[] tag)
+	throws DbException;
 }

components/net/sf/briar/transport/ConnectionDispatcherImpl.java

@@ -1,7 +1,9 @@
 package net.sf.briar.transport;
 
+import java.io.EOFException;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.concurrent.Executor;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -16,7 +18,7 @@ import net.sf.briar.api.transport.BatchTransportWriter;
 import net.sf.briar.api.transport.ConnectionContext;
 import net.sf.briar.api.transport.ConnectionDispatcher;
 import net.sf.briar.api.transport.ConnectionRecogniser;
-import net.sf.briar.api.transport.ConnectionRecogniser.Callback;
+import net.sf.briar.api.transport.ConnectionRecogniserExecutor;
 import net.sf.briar.api.transport.StreamTransportConnection;
 import net.sf.briar.api.transport.TransportConstants;
 
@@ -27,56 +29,24 @@ class ConnectionDispatcherImpl implements ConnectionDispatcher {
 	private static final Logger LOG =
 		Logger.getLogger(ConnectionDispatcherImpl.class.getName());
 
+	private final Executor executor;
 	private final ConnectionRecogniser recogniser;
 	private final BatchConnectionFactory batchConnFactory;
 	private final StreamConnectionFactory streamConnFactory;
 
 	@Inject
-	ConnectionDispatcherImpl(ConnectionRecogniser recogniser,
+	ConnectionDispatcherImpl(@ConnectionRecogniserExecutor Executor executor,
+			ConnectionRecogniser recogniser,
 			BatchConnectionFactory batchConnFactory,
 			StreamConnectionFactory streamConnFactory) {
+		this.executor = executor;
 		this.recogniser = recogniser;
 		this.batchConnFactory = batchConnFactory;
 		this.streamConnFactory = streamConnFactory;
 	}
 
-	public void dispatchReader(TransportId t, final BatchTransportReader r) {
-		// Read the tag
-		final byte[] tag;
-		try {
-			tag = readTag(r.getInputStream());
-		} catch(IOException e) {
-			if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
-			r.dispose(false);
-			return;
-		}
-		// Get the connection context asynchronously
-		recogniser.acceptConnection(t, tag, new Callback() {
-
-			public void connectionAccepted(ConnectionContext ctx) {
-				batchConnFactory.createIncomingConnection(ctx, r, tag);
-			}
-
-			public void connectionRejected() {
-				r.dispose(true);
-			}
-
-			public void handleException(DbException e) {
-				if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
-				r.dispose(false);
-			}
-		});
-	}
-
-	private byte[] readTag(InputStream in) throws IOException {
-		byte[] b = new byte[TransportConstants.TAG_LENGTH];
-		int offset = 0;
-		while(offset < b.length) {
-			int read = in.read(b, offset, b.length - offset);
-			if(read == -1) throw new IOException();
-			offset += read;
-		}
-		return b;
+	public void dispatchReader(TransportId t, BatchTransportReader r) {
+		executor.execute(new DispatchBatchConnection(t, r));
 	}
 
 	public void dispatchWriter(ContactId c, TransportIndex i,
@@ -85,36 +55,76 @@ class ConnectionDispatcherImpl implements ConnectionDispatcher {
 	}
 
 	public void dispatchIncomingConnection(TransportId t,
-			final StreamTransportConnection s) {
-		// Read the tag
-		final byte[] tag;
-		try {
-			tag = readTag(s.getInputStream());
-		} catch(IOException e) {
-			if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
-			s.dispose(false);
-			return;
-		}
-		// Get the connection context asynchronously
-		recogniser.acceptConnection(t, tag, new Callback() {
-
-			public void connectionAccepted(ConnectionContext ctx) {
-				streamConnFactory.createIncomingConnection(ctx, s, tag);
-			}
-
-			public void connectionRejected() {
-				s.dispose(true);
-			}
-
-			public void handleException(DbException e) {
-				if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
-				s.dispose(false);
-			}
-		});
+			StreamTransportConnection s) {
+		executor.execute(new DispatchStreamConnection(t, s));
 	}
 
 	public void dispatchOutgoingConnection(ContactId c, TransportIndex i,
 			StreamTransportConnection s) {
 		streamConnFactory.createOutgoingConnection(c, i, s);
 	}
-}
+
+	private byte[] readTag(InputStream in) throws IOException {
+		byte[] b = new byte[TransportConstants.TAG_LENGTH];
+		int offset = 0;
+		while(offset < b.length) {
+			int read = in.read(b, offset, b.length - offset);
+			if(read == -1) throw new EOFException();
+			offset += read;
+		}
+		return b;
+	}
+
+	private class DispatchBatchConnection implements Runnable {
+
+		private final TransportId t;
+		private final BatchTransportReader r;
+
+		private DispatchBatchConnection(TransportId t, BatchTransportReader r) {
+			this.t = t;
+			this.r = r;
+		}
+
+		public void run() {
+			try {
+				byte[] tag = readTag(r.getInputStream());
+				ConnectionContext ctx = recogniser.acceptConnection(t, tag);
+				if(ctx == null) r.dispose(true);
+				else batchConnFactory.createIncomingConnection(ctx, r, tag);
+			} catch(DbException e) {
+				if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
+				r.dispose(false);
+			} catch(IOException e) {
+				if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
+				r.dispose(false);
+			}
+		}
+	}
+
+	private class DispatchStreamConnection implements Runnable {
+
+		private final TransportId t;
+		private final StreamTransportConnection s;
+
+		private DispatchStreamConnection(TransportId t,
+				StreamTransportConnection s) {
+			this.t = t;
+			this.s = s;
+		}
+
+		public void run() {
+			try {
+				byte[] tag = readTag(s.getInputStream());
+				ConnectionContext ctx = recogniser.acceptConnection(t, tag);
+				if(ctx == null) s.dispose(true);
+				else streamConnFactory.createIncomingConnection(ctx, s, tag);
+			} catch(DbException e) {
+				if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
+				s.dispose(false);
+			} catch(IOException e) {
+				if(LOG.isLoggable(Level.WARNING)) LOG.warning(e.getMessage());
+				s.dispose(false);
+			}
+		}
+	}
+}

components/net/sf/briar/transport/ConnectionRecogniserImpl.java

@@ -107,23 +107,7 @@ DatabaseListener {
 		return new Bytes(tag);
 	}
 
-	public void acceptConnection(final TransportId t, final byte[] tag,
-			final Callback callback) {
-		executor.execute(new Runnable() {
-			public void run() {
-				try {
-					ConnectionContext ctx = acceptConnection(t, tag);
-					if(ctx == null) callback.connectionRejected();
-					else callback.connectionAccepted(ctx);
-				} catch(DbException e) {
-					callback.handleException(e);
-				}
-			}
-		});
-	}
-
-	// Package access for testing
-	ConnectionContext acceptConnection(TransportId t, byte[] tag)
+	public ConnectionContext acceptConnection(TransportId t, byte[] tag)
 	throws DbException {
 		if(tag.length != TAG_LENGTH)
 			throw new IllegalArgumentException();

components/net/sf/briar/transport/TransportModule.java

@@ -12,7 +12,6 @@ import net.sf.briar.api.transport.ConnectionWindowFactory;
 import net.sf.briar.api.transport.ConnectionWriterFactory;
 
 import com.google.inject.AbstractModule;
-import com.google.inject.Singleton;
 
 public class TransportModule extends AbstractModule {
 
@@ -23,8 +22,7 @@ public class TransportModule extends AbstractModule {
 		bind(ConnectionDispatcher.class).to(ConnectionDispatcherImpl.class);
 		bind(ConnectionReaderFactory.class).to(
 				ConnectionReaderFactoryImpl.class);
-		bind(ConnectionRecogniser.class).to(ConnectionRecogniserImpl.class).in(
-				Singleton.class);
+		bind(ConnectionRecogniser.class).to(ConnectionRecogniserImpl.class);
 		bind(ConnectionWindowFactory.class).to(
 				ConnectionWindowFactoryImpl.class);
 		bind(ConnectionWriterFactory.class).to(

test/net/sf/briar/protocol/batch/BatchConnectionReadWriteTest.java

@@ -8,14 +8,12 @@ import java.io.File;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Random;
-import java.util.concurrent.CountDownLatch;
 
 import junit.framework.TestCase;
 import net.sf.briar.TestDatabaseModule;
 import net.sf.briar.TestUtils;
 import net.sf.briar.api.ContactId;
 import net.sf.briar.api.db.DatabaseComponent;
-import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.db.event.DatabaseEvent;
 import net.sf.briar.api.db.event.DatabaseListener;
 import net.sf.briar.api.db.event.MessagesAddedEvent;
@@ -30,7 +28,6 @@ import net.sf.briar.api.protocol.TransportUpdate;
 import net.sf.briar.api.transport.ConnectionContext;
 import net.sf.briar.api.transport.ConnectionReaderFactory;
 import net.sf.briar.api.transport.ConnectionRecogniser;
-import net.sf.briar.api.transport.ConnectionRecogniser.Callback;
 import net.sf.briar.api.transport.ConnectionWriterFactory;
 import net.sf.briar.crypto.CryptoModule;
 import net.sf.briar.db.DatabaseModule;
@@ -158,10 +155,7 @@ public class BatchConnectionReadWriteTest extends TestCase {
 		byte[] tag = new byte[TAG_LENGTH];
 		int read = in.read(tag);
 		assertEquals(tag.length, read);
-		TestCallback callback = new TestCallback();
-		rec.acceptConnection(transportId, tag, callback);
-		callback.latch.await();
-		ConnectionContext ctx = callback.ctx;
+		ConnectionContext ctx = rec.acceptConnection(transportId, tag);
 		assertNotNull(ctx);
 		assertEquals(contactId, ctx.getContactId());
 		assertEquals(transportIndex, ctx.getTransportIndex());
@@ -198,25 +192,4 @@ public class BatchConnectionReadWriteTest extends TestCase {
 			if(e instanceof MessagesAddedEvent) messagesAdded = true;
 		}
 	}
-
-	private static class TestCallback implements Callback {
-
-		private final CountDownLatch latch = new CountDownLatch(1);
-		private ConnectionContext ctx = null;
-
-		public void connectionAccepted(ConnectionContext ctx) {
-			this.ctx = ctx;
-			latch.countDown();
-		}
-
-		public void connectionRejected() {
-			fail();
-			latch.countDown();
-		}
-
-		public void handleException(DbException e) {
-			fail();
-			latch.countDown();
-		}
-	}
 }