Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / io / MappedByteBufferPool.java

diff --git a/lib/jetty/org/eclipse/jetty/io/MappedByteBufferPool.java b/lib/jetty/org/eclipse/jetty/io/MappedByteBufferPool.java
new file mode 100644 (file)
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+++ b/lib/jetty/org/eclipse/jetty/io/MappedByteBufferPool.java
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+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.io;
+
+import java.nio.ByteBuffer;
+import java.util.Queue;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.ConcurrentMap;
+
+import org.eclipse.jetty.util.BufferUtil;
+
+public class MappedByteBufferPool implements ByteBufferPool
+{
+    private final ConcurrentMap<Integer, Queue<ByteBuffer>> directBuffers = new ConcurrentHashMap<>();
+    private final ConcurrentMap<Integer, Queue<ByteBuffer>> heapBuffers = new ConcurrentHashMap<>();
+    private final int factor;
+
+    public MappedByteBufferPool()
+    {
+        this(1024);
+    }
+
+    public MappedByteBufferPool(int factor)
+    {
+        this.factor = factor;
+    }
+
+    @Override
+    public ByteBuffer acquire(int size, boolean direct)
+    {
+        int bucket = bucketFor(size);
+        ConcurrentMap<Integer, Queue<ByteBuffer>> buffers = buffersFor(direct);
+
+        ByteBuffer result = null;
+        Queue<ByteBuffer> byteBuffers = buffers.get(bucket);
+        if (byteBuffers != null)
+            result = byteBuffers.poll();
+
+        if (result == null)
+        {
+            int capacity = bucket * factor;
+            result = direct ? BufferUtil.allocateDirect(capacity) : BufferUtil.allocate(capacity);
+        }
+
+        BufferUtil.clear(result);
+        return result;
+    }
+
+    @Override
+    public void release(ByteBuffer buffer)
+    {
+        if (buffer == null)
+            return; // nothing to do
+        
+        // validate that this buffer is from this pool
+        assert((buffer.capacity() % factor) == 0);
+        
+        int bucket = bucketFor(buffer.capacity());
+        ConcurrentMap<Integer, Queue<ByteBuffer>> buffers = buffersFor(buffer.isDirect());
+
+        // Avoid to create a new queue every time, just to be discarded immediately
+        Queue<ByteBuffer> byteBuffers = buffers.get(bucket);
+        if (byteBuffers == null)
+        {
+            byteBuffers = new ConcurrentLinkedQueue<>();
+            Queue<ByteBuffer> existing = buffers.putIfAbsent(bucket, byteBuffers);
+            if (existing != null)
+                byteBuffers = existing;
+        }
+
+        BufferUtil.clear(buffer);
+        byteBuffers.offer(buffer);
+    }
+
+    public void clear()
+    {
+        directBuffers.clear();
+        heapBuffers.clear();
+    }
+
+    private int bucketFor(int size)
+    {
+        int bucket = size / factor;
+        if (size % factor > 0)
+            ++bucket;
+        return bucket;
+    }
+
+    // Package local for testing
+    ConcurrentMap<Integer, Queue<ByteBuffer>> buffersFor(boolean direct)
+    {
+        return direct ? directBuffers : heapBuffers;
+    }
+}