Fixes #12687 - Buffer reusal in the BufferingResponseListener.

documentation/jetty/modules/code/examples/src/main/java/org/eclipse/jetty/docs/programming/client/http/HTTPClientDocs.java

@@ -35,7 +35,6 @@
 import org.eclipse.jetty.client.Authentication;
 import org.eclipse.jetty.client.AuthenticationStore;
 import org.eclipse.jetty.client.BasicAuthentication;
-import org.eclipse.jetty.client.BufferingResponseListener;
 import org.eclipse.jetty.client.BytesRequestContent;
 import org.eclipse.jetty.client.CompletableResponseListener;
 import org.eclipse.jetty.client.Connection;
@@ -55,6 +54,7 @@
 import org.eclipse.jetty.client.Request;
 import org.eclipse.jetty.client.Response;
 import org.eclipse.jetty.client.Result;
+import org.eclipse.jetty.client.RetainingResponseListener;
 import org.eclipse.jetty.client.RoundRobinConnectionPool;
 import org.eclipse.jetty.client.Socks5;
 import org.eclipse.jetty.client.Socks5Proxy;
@@ -460,15 +460,15 @@ public void futureResponseListener() throws Exception
         // end::completableResponseListener[]
     }
 
-    public void bufferingResponseListener() throws Exception
+    public void retainingResponseListener() throws Exception
     {
         HttpClient httpClient = new HttpClient();
         httpClient.start();
 
-        // tag::bufferingResponseListener[]
+        // tag::retainingResponseListener[]
         httpClient.newRequest("http://domain.com/path")
-            // Buffer response content up to 8 MiB
-            .send(new BufferingResponseListener(8 * 1024 * 1024)
+            // Accumulate response content up to 8 MiB.
+            .send(new RetainingResponseListener(8 * 1024 * 1024)
             {
                 @Override
                 public void onComplete(Result result)
@@ -480,7 +480,7 @@ public void onComplete(Result result)
                     }
                 }
             });
-        // end::bufferingResponseListener[]
+        // end::retainingResponseListener[]
     }
 
     public void inputStreamResponseListener() throws Exception

documentation/jetty/modules/programming-guide/pages/client/http.adoc

@@ -497,14 +497,14 @@ include::code:example$src/main/java/org/eclipse/jetty/docs/programming/client/ht
 
 If the response content length is exceeded, the response will be aborted, and an exception will be thrown by method `get(\...)`.
 
-You can buffer the response content in memory also using the <<non-blocking,non-blocking APIs>>, via the `BufferingResponseListener` utility class:
+You can accumulate the response content in memory also using the <<non-blocking,non-blocking APIs>>, via the `RetainingResponseListener` utility class:
 
 [,java,indent=0]
 ----
-include::code:example$src/main/java/org/eclipse/jetty/docs/programming/client/http/HTTPClientDocs.java[tags=bufferingResponseListener]
+include::code:example$src/main/java/org/eclipse/jetty/docs/programming/client/http/HTTPClientDocs.java[tags=retainingResponseListener]
 ----
 
-If you want to avoid buffering, you can wait for the response and then stream the content using the `InputStreamResponseListener` utility class:
+If you want to avoid accumulation, you can wait for the response and then stream the content using the `InputStreamResponseListener` utility class:
 
 [,java,indent=0]
 ----

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/AbstractResponseListener.java

@@ -0,0 +1,97 @@
+//
+// ========================================================================
+// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.client;
+
+import java.util.Locale;
+
+import org.eclipse.jetty.http.HttpFields;
+import org.eclipse.jetty.http.HttpHeader;
+import org.eclipse.jetty.http.HttpMethod;
+
+public abstract class AbstractResponseListener implements Response.Listener
+{
+    private final int maxLength;
+    private String encoding;
+    private String mediaType;
+
+    public AbstractResponseListener()
+    {
+        this(2 * 1024 * 1024);
+    }
+
+    public AbstractResponseListener(int maxLength)
+    {
+        if (maxLength < 0)
+            throw new IllegalArgumentException("Invalid max length " + maxLength);
+        this.maxLength = maxLength;
+    }
+
+    public String getEncoding()
+    {
+        return encoding;
+    }
+
+    public int getMaxLength()
+    {
+        return maxLength;
+    }
+
+    public String getMediaType()
+    {
+        return mediaType;
+    }
+
+    @Override
+    public void onHeaders(Response response)
+    {
+        Request request = response.getRequest();
+        HttpFields headers = response.getHeaders();
+        long length = headers.getLongField(HttpHeader.CONTENT_LENGTH);
+        if (HttpMethod.HEAD.is(request.getMethod()))
+            length = 0;
+        if (length > maxLength)
+        {
+            response.abort(new IllegalArgumentException("Buffering capacity " + maxLength + " exceeded"));
+            return;
+        }
+
+        String contentType = headers.get(HttpHeader.CONTENT_TYPE);
+        if (contentType != null)
+        {
+            String media = contentType;
+
+            String charset = "charset=";
+            int index = contentType.toLowerCase(Locale.ENGLISH).indexOf(charset);
+            if (index > 0)
+            {
+                media = contentType.substring(0, index);
+                String encoding = contentType.substring(index + charset.length());
+                // Sometimes charsets arrive with an ending semicolon.
+                int semicolon = encoding.indexOf(';');
+                if (semicolon > 0)
+                    encoding = encoding.substring(0, semicolon).trim();
+                // Sometimes charsets are quoted.
+                int lastIndex = encoding.length() - 1;
+                if (encoding.charAt(0) == '"' && encoding.charAt(lastIndex) == '"')
+                    encoding = encoding.substring(1, lastIndex).trim();
+                this.encoding = encoding;
+            }
+
+            int semicolon = media.indexOf(';');
+            if (semicolon > 0)
+                media = media.substring(0, semicolon).trim();
+            this.mediaType = media;
+        }
+    }
+}

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/AuthenticationProtocolHandler.java

@@ -115,7 +115,7 @@ else if (m.group("token68") != null)
         return headerInfos;
     }
 
-    private class AuthenticationListener extends BufferingResponseListener
+    private class AuthenticationListener extends RetainingResponseListener
     {
         private AuthenticationListener()
         {
@@ -125,6 +125,7 @@ private AuthenticationListener()
         @Override
         public void onSuccess(Response response)
         {
+            super.onSuccess(response);
             // The request may still be sending content, stop it.
             Request request = response.getRequest();
             if (request.getBody() != null)

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/BufferingResponseListener.java

@@ -18,12 +18,8 @@
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
-import java.util.Locale;
 
 import org.eclipse.jetty.client.Response.Listener;
-import org.eclipse.jetty.http.HttpFields;
-import org.eclipse.jetty.http.HttpHeader;
-import org.eclipse.jetty.http.HttpMethod;
 import org.eclipse.jetty.util.BufferUtil;
 
 /**
@@ -32,13 +28,16 @@
  * <p>The content may be retrieved from {@link #onSuccess(Response)} or {@link #onComplete(Result)}
  * via {@link #getContent()} or {@link #getContentAsString()}.</p>
  * <p>Instances of this class are not reusable, so one must be allocated for each request.</p>
+ * <p>The implementation is not very efficient, as it copies (possibly multiple times)
+ * the response content into a buffer.
+ * Use {@link RetainingResponseListener} for a more efficient implementation.</p>
+ *
+ * @deprecated use {@link RetainingResponseListener} instead
  */
-public abstract class BufferingResponseListener implements Listener
+@Deprecated(since = "12.1.0", forRemoval = true)
+public abstract class BufferingResponseListener extends AbstractResponseListener
 {
-    private final int maxLength;
     private ByteBuffer buffer;
-    private String mediaType;
-    private String encoding;
 
     /**
      * Creates an instance with a default maximum length of 2 MiB.
@@ -55,52 +54,7 @@ public BufferingResponseListener()
      */
     public BufferingResponseListener(int maxLength)
     {
-        if (maxLength < 0)
-            throw new IllegalArgumentException("Invalid max length " + maxLength);
-        this.maxLength = maxLength;
-    }
-
-    @Override
-    public void onHeaders(Response response)
-    {
-        Request request = response.getRequest();
-        HttpFields headers = response.getHeaders();
-        long length = headers.getLongField(HttpHeader.CONTENT_LENGTH);
-        if (HttpMethod.HEAD.is(request.getMethod()))
-            length = 0;
-        if (length > maxLength)
-        {
-            response.abort(new IllegalArgumentException("Buffering capacity " + maxLength + " exceeded"));
-            return;
-        }
-
-        String contentType = headers.get(HttpHeader.CONTENT_TYPE);
-        if (contentType != null)
-        {
-            String media = contentType;
-
-            String charset = "charset=";
-            int index = contentType.toLowerCase(Locale.ENGLISH).indexOf(charset);
-            if (index > 0)
-            {
-                media = contentType.substring(0, index);
-                String encoding = contentType.substring(index + charset.length());
-                // Sometimes charsets arrive with an ending semicolon.
-                int semicolon = encoding.indexOf(';');
-                if (semicolon > 0)
-                    encoding = encoding.substring(0, semicolon).trim();
-                // Sometimes charsets are quoted.
-                int lastIndex = encoding.length() - 1;
-                if (encoding.charAt(0) == '"' && encoding.charAt(lastIndex) == '"')
-                    encoding = encoding.substring(1, lastIndex).trim();
-                this.encoding = encoding;
-            }
-
-            int semicolon = media.indexOf(';');
-            if (semicolon > 0)
-                media = media.substring(0, semicolon).trim();
-            this.mediaType = media;
-        }
+        super(maxLength);
     }
 
     @Override
@@ -112,6 +66,7 @@ public void onContent(Response response, ByteBuffer content)
         if (length > BufferUtil.space(buffer))
         {
             int remaining = buffer == null ? 0 : buffer.remaining();
+            int maxLength = getMaxLength();
             if (remaining + length > maxLength)
                 response.abort(new IllegalArgumentException("Buffering capacity " + maxLength + " exceeded"));
             int requiredCapacity = buffer == null ? length : buffer.capacity() + length;
@@ -124,24 +79,14 @@ public void onContent(Response response, ByteBuffer content)
     @Override
     public abstract void onComplete(Result result);
 
-    public String getMediaType()
-    {
-        return mediaType;
-    }
-
-    public String getEncoding()
-    {
-        return encoding;
-    }
-
     /**
      * @return the content as bytes
      * @see #getContentAsString()
      */
     public byte[] getContent()
     {
         if (buffer == null)
-            return new byte[0];
+            return BufferUtil.EMPTY_BYTES;
         return BufferUtil.toArray(buffer);
     }
 
@@ -152,7 +97,7 @@ public byte[] getContent()
      */
     public String getContentAsString()
     {
-        String encoding = this.encoding;
+        String encoding = getEncoding();
         if (encoding == null)
             return getContentAsString(StandardCharsets.UTF_8);
         return getContentAsString(encoding);

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/CompletableResponseListener.java

@@ -18,7 +18,7 @@
 import org.eclipse.jetty.client.internal.HttpContentResponse;
 
 /**
- * <p>A {@link BufferingResponseListener} that sends a {@link Request}
+ * <p>A {@link RetainingResponseListener} that sends a {@link Request}
  * and returns a {@link CompletableFuture} that is completed when
  * {@link #onComplete(Result)} is called.</p>
  * <p>Typical usage:</p>
@@ -34,7 +34,7 @@
  * ContentResponse response = completable.get(5, TimeUnit.SECONDS);
  * }</pre>
  */
-public class CompletableResponseListener extends BufferingResponseListener
+public class CompletableResponseListener extends RetainingResponseListener
 {
     private final CompletableFuture<ContentResponse> completable = new CompletableFuture<>();
     private final Request request;

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/ContinueProtocolHandler.java

@@ -61,11 +61,13 @@ protected Runnable onContinue(Request request)
         return null;
     }
 
-    protected class ContinueListener extends BufferingResponseListener
+    protected class ContinueListener extends RetainingResponseListener
     {
         @Override
         public void onSuccess(Response response)
         {
+            super.onSuccess(response);
+
             // Handling of success must be done here and not from onComplete(),
             // since the onComplete() is not invoked because the request is not completed yet.
 
@@ -104,6 +106,8 @@ public void onSuccess(Response response)
         @Override
         public void onFailure(Response response, Throwable failure)
         {
+            super.onFailure(response, failure);
+
             HttpConversation conversation = ((HttpRequest)response.getRequest()).getConversation();
             // Mark the 100 Continue response as handled
             conversation.setAttribute(ATTRIBUTE, Boolean.TRUE);

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/EarlyHintsProtocolHandler.java

@@ -50,11 +50,13 @@ protected void onEarlyHints(Request request, HttpFields responseHeaders)
     {
     }
 
-    private class EarlyHintsListener extends BufferingResponseListener
+    private class EarlyHintsListener extends RetainingResponseListener
     {
         @Override
         public void onSuccess(Response response)
         {
+            super.onSuccess(response);
+
             Request request = response.getRequest();
             HttpConversation conversation = ((HttpRequest)request).getConversation();
 
@@ -72,6 +74,8 @@ public void onSuccess(Response response)
         @Override
         public void onFailure(Response response, Throwable failure)
         {
+            super.onFailure(response, failure);
+
             HttpConversation conversation = ((HttpRequest)response.getRequest()).getConversation();
             // Reset the conversation listeners to allow the conversation to be completed.
             conversation.updateResponseListeners(null);

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/HttpClient.java

@@ -233,6 +233,7 @@ protected void doStart() throws Exception
         if (decoderFactories.isEmpty())
         {
             TypeUtil.serviceStream(ServiceLoader.load(Compression.class))
+                .peek(c -> c.setByteBufferPool(getByteBufferPool()))
                 .forEach(c -> decoderFactories.put(new CompressionContentDecoderFactory(c)));
         }
 

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/HttpRedirector.java

@@ -107,7 +107,7 @@ public Result redirect(Request request, Response response) throws InterruptedExc
     {
         AtomicReference<Result> resultRef = new AtomicReference<>();
         CountDownLatch latch = new CountDownLatch(1);
-        Request redirect = redirect(request, response, new BufferingResponseListener()
+        Request redirect = redirect(request, response, new RetainingResponseListener()
         {
             @Override
             public void onComplete(Result result)