Bypass ConnectionSemaphore when no connection limit is set, close AsyncHttpClient#1467

Motivation:

AsyncHttpClient#1379 introduced ConnectionSemaphore to deal with connection limits.
When no such limit is set, which is the default, we could bypass all
this code.

Modification:

Don’t create ConnectionSemaphore when no limit is set and bypass all
related code when it’s null.

Result:

More simple code path and possibly better performance

Author: slandelle

client/src/main/java/org/asynchttpclient/DefaultAsyncHttpClient.java

@@ -44,16 +44,13 @@ public class DefaultAsyncHttpClient implements AsyncHttpClient {
     private final AsyncHttpClientConfig config;
     private final AtomicBoolean closed = new AtomicBoolean(false);
     private final ChannelManager channelManager;
-    private final ConnectionSemaphore connectionSemaphore;
     private final NettyRequestSender requestSender;
     private final boolean allowStopNettyTimer;
     private final Timer nettyTimer;
 
     /**
      * Default signature calculator to use for all requests constructed by this
      * client instance.
-     *
-     * @since 1.1
      */
     protected SignatureCalculator signatureCalculator;
 
@@ -86,7 +83,7 @@ public DefaultAsyncHttpClient(AsyncHttpClientConfig config) {
         nettyTimer = allowStopNettyTimer ? newNettyTimer() : config.getNettyTimer();
 
         channelManager = new ChannelManager(config, nettyTimer);
-        connectionSemaphore = new ConnectionSemaphore(config);
+        ConnectionSemaphore connectionSemaphore = ConnectionSemaphore.newConnectionSemaphore(config);
         requestSender = new NettyRequestSender(config, channelManager, connectionSemaphore, nettyTimer, new AsyncHttpClientState(closed));
         channelManager.configureBootstraps(requestSender);
     }

client/src/main/java/org/asynchttpclient/netty/NettyResponseFuture.java

@@ -90,11 +90,14 @@ public final class NettyResponseFuture<V> implements ListenableFuture<V> {
     @SuppressWarnings("rawtypes")
     private static final AtomicIntegerFieldUpdater<NettyResponseFuture> contentProcessedField = AtomicIntegerFieldUpdater.newUpdater(NettyResponseFuture.class, "contentProcessed");
     @SuppressWarnings("rawtypes")
-    private static final AtomicIntegerFieldUpdater<NettyResponseFuture> onThrowableCalledField = AtomicIntegerFieldUpdater.newUpdater(NettyResponseFuture.class, "onThrowableCalled");
+    private static final AtomicIntegerFieldUpdater<NettyResponseFuture> onThrowableCalledField = AtomicIntegerFieldUpdater.newUpdater(NettyResponseFuture.class,
+            "onThrowableCalled");
     @SuppressWarnings("rawtypes")
-    private static final AtomicReferenceFieldUpdater<NettyResponseFuture, TimeoutsHolder> timeoutsHolderField = AtomicReferenceFieldUpdater.newUpdater(NettyResponseFuture.class, TimeoutsHolder.class, "timeoutsHolder");
+    private static final AtomicReferenceFieldUpdater<NettyResponseFuture, TimeoutsHolder> timeoutsHolderField = AtomicReferenceFieldUpdater.newUpdater(NettyResponseFuture.class,
+            TimeoutsHolder.class, "timeoutsHolder");
     @SuppressWarnings("rawtypes")
-    private static final AtomicReferenceFieldUpdater<NettyResponseFuture, Object> partitionKeyLockField = AtomicReferenceFieldUpdater.newUpdater(NettyResponseFuture.class, Object.class, "partitionKeyLock");
+    private static final AtomicReferenceFieldUpdater<NettyResponseFuture, Object> partitionKeyLockField = AtomicReferenceFieldUpdater.newUpdater(NettyResponseFuture.class,
+            Object.class, "partitionKeyLock");
 
     // volatile where we need CAS ops
     private volatile int redirectCount = 0;
@@ -120,12 +123,12 @@ public final class NettyResponseFuture<V> implements ListenableFuture<V> {
     private Realm proxyRealm;
     public Throwable pendingException;
 
-    public NettyResponseFuture(Request originalRequest,//
-            AsyncHandler<V> asyncHandler,//
-            NettyRequest nettyRequest,//
-            int maxRetry,//
-            ChannelPoolPartitioning connectionPoolPartitioning,//
-            ConnectionSemaphore connectionSemaphore,//
+    public NettyResponseFuture(Request originalRequest, //
+            AsyncHandler<V> asyncHandler, //
+            NettyRequest nettyRequest, //
+            int maxRetry, //
+            ChannelPoolPartitioning connectionPoolPartitioning, //
+            ConnectionSemaphore connectionSemaphore, //
             ProxyServer proxyServer) {
 
         this.asyncHandler = asyncHandler;
@@ -138,6 +141,10 @@ public NettyResponseFuture(Request originalRequest,//
     }
 
     private void releasePartitionKeyLock() {
+        if (connectionSemaphore == null) {
+            return;
+        }
+
         Object partitionKey = takePartitionKeyLock();
         if (partitionKey != null) {
             connectionSemaphore.releaseChannelLock(partitionKey);
@@ -484,7 +491,7 @@ public Object getPartitionKey() {
     }
 
     public void acquirePartitionLockLazily() throws IOException {
-        if (partitionKeyLock != null) {
+        if (connectionSemaphore == null || partitionKeyLock != null) {
             return;
         }
 

client/src/main/java/org/asynchttpclient/netty/channel/ConnectionSemaphore.java

@@ -29,6 +29,10 @@
  */
 public class ConnectionSemaphore {
 
+    public static ConnectionSemaphore newConnectionSemaphore(AsyncHttpClientConfig config) {
+        return config.getMaxConnections() > 0 || config.getMaxConnectionsPerHost() > 0 ? new ConnectionSemaphore(config) : null;
+    }
+
     private final int maxTotalConnections;
     private final NonBlockingSemaphoreLike freeChannels;
     private final int maxConnectionsPerHost;
@@ -37,7 +41,7 @@ public class ConnectionSemaphore {
     private final IOException tooManyConnections;
     private final IOException tooManyConnectionsPerHost;
 
-    public ConnectionSemaphore(AsyncHttpClientConfig config) {
+    private ConnectionSemaphore(AsyncHttpClientConfig config) {
         tooManyConnections = unknownStackTrace(new TooManyConnectionsException(config.getMaxConnections()), ConnectionSemaphore.class, "acquireChannelLock");
         tooManyConnectionsPerHost = unknownStackTrace(new TooManyConnectionsPerHostException(config.getMaxConnectionsPerHost()), ConnectionSemaphore.class, "acquireChannelLock");
         maxTotalConnections = config.getMaxConnections();

client/src/main/java/org/asynchttpclient/netty/channel/NettyConnectListener.java

@@ -89,7 +89,7 @@ private void writeRequest(Channel channel) {
 
     public void onSuccess(Channel channel, InetSocketAddress remoteAddress) {
 
-        {
+        if (connectionSemaphore != null) {
             // transfer lock from future to channel
             Object partitionKeyLock = future.takePartitionKeyLock();