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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2014 Red Hat, Inc., and individual contributors
 * as indicated by the @author tags.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package io.undertow.server;

import io.undertow.UndertowMessages;
import io.undertow.connector.ByteBufferPool;
import io.undertow.connector.PooledByteBuffer;

import java.lang.ref.WeakReference;
import java.nio.ByteBuffer;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;

/**
 * A byte buffer pool that supports reference counted pools.
 *
 * @author Stuart Douglas
 */
// TODO: move this somewhere more appropriate
public class DefaultByteBufferPool implements ByteBufferPool {

    private final ThreadLocalCache threadLocalCache = new ThreadLocalCache();
    // Access requires synchronization on the threadLocalDataList instance
    private final List> threadLocalDataList = new ArrayList<>();
    private final ConcurrentLinkedQueue queue = new ConcurrentLinkedQueue<>();

    private final boolean direct;
    private final int bufferSize;
    private final int maximumPoolSize;
    private final int threadLocalCacheSize;
    private final int leakDectionPercent;
    private int count; //racily updated count used in leak detection

    @SuppressWarnings({"unused", "FieldCanBeLocal"})
    private volatile int currentQueueLength = 0;
    private static final AtomicIntegerFieldUpdater currentQueueLengthUpdater = AtomicIntegerFieldUpdater.newUpdater(DefaultByteBufferPool.class, "currentQueueLength");

    @SuppressWarnings({"unused", "FieldCanBeLocal"})
    private volatile int reclaimedThreadLocals = 0;
    private static final AtomicIntegerFieldUpdater reclaimedThreadLocalsUpdater = AtomicIntegerFieldUpdater.newUpdater(DefaultByteBufferPool.class, "reclaimedThreadLocals");

    private volatile boolean closed;

    private final DefaultByteBufferPool arrayBackedPool;


    /**
     * @param direct               If this implementation should use direct buffers
     * @param bufferSize           The buffer size to use
     */
    public DefaultByteBufferPool(boolean direct, int bufferSize) {
        this(direct, bufferSize, -1, 12, 0);
    }
    /**
     * @param direct               If this implementation should use direct buffers
     * @param bufferSize           The buffer size to use
     * @param maximumPoolSize      The maximum pool size, in number of buffers, it does not include buffers in thread local caches
     * @param threadLocalCacheSize The maximum number of buffers that can be stored in a thread local cache
     */
    public DefaultByteBufferPool(boolean direct, int bufferSize, int maximumPoolSize, int threadLocalCacheSize, int leakDecetionPercent) {
        this.direct = direct;
        this.bufferSize = bufferSize;
        this.maximumPoolSize = maximumPoolSize;
        this.threadLocalCacheSize = threadLocalCacheSize;
        this.leakDectionPercent = leakDecetionPercent;
        if(direct) {
            arrayBackedPool = new DefaultByteBufferPool(false, bufferSize, maximumPoolSize, 0, leakDecetionPercent);
        } else {
            arrayBackedPool = this;
        }
    }


    /**
     * @param direct               If this implementation should use direct buffers
     * @param bufferSize           The buffer size to use
     * @param maximumPoolSize      The maximum pool size, in number of buffers, it does not include buffers in thread local caches
     * @param threadLocalCacheSize The maximum number of buffers that can be stored in a thread local cache
     */
    public DefaultByteBufferPool(boolean direct, int bufferSize, int maximumPoolSize, int threadLocalCacheSize) {
        this(direct, bufferSize, maximumPoolSize, threadLocalCacheSize, 0);
    }

    @Override
    public int getBufferSize() {
        return bufferSize;
    }

    @Override
    public boolean isDirect() {
        return direct;
    }

    @Override
    public PooledByteBuffer allocate() {
        if (closed) {
            throw UndertowMessages.MESSAGES.poolIsClosed();
        }
        ByteBuffer buffer = null;
        ThreadLocalData local = null;
        if(threadLocalCacheSize > 0) {
            local = threadLocalCache.get();
            if (local != null) {
                buffer = local.buffers.poll();
            } else {
                local = new ThreadLocalData();
                synchronized (threadLocalDataList) {
                    if (closed) {
                        throw UndertowMessages.MESSAGES.poolIsClosed();
                    }
                    cleanupThreadLocalData();
                    threadLocalDataList.add(new WeakReference<>(local));
                    threadLocalCache.set(local);
                }

            }
        }
        if (buffer == null) {
            buffer = queue.poll();
            if (buffer != null) {
                currentQueueLengthUpdater.decrementAndGet(this);
                //buffer.clear();
            }
        }
        if (buffer == null) {
            if (direct) {
                buffer = ByteBuffer.allocateDirect(bufferSize);
            } else {
                buffer = ByteBuffer.allocate(bufferSize);
            }
        }
        if(local != null) {
            if(local.allocationDepth < threadLocalCacheSize) { //prevent overflow if the thread only allocates and never frees
                local.allocationDepth++;
            }
        }
        buffer.clear();
        return new DefaultPooledBuffer(this, buffer, leakDectionPercent == 0 ? false : (++count % 100 < leakDectionPercent));
    }

    @Override
    public ByteBufferPool getArrayBackedPool() {
        return arrayBackedPool;
    }

    private void cleanupThreadLocalData() {
        // Called under lock, and only when at least quarter of the capacity has been collected.

        final int size = threadLocalDataList.size();

        if (reclaimedThreadLocals > (size / 4)) {
            int j = 0;
            for (int i = 0; i < size; i++) {
                WeakReference ref = threadLocalDataList.get(i);
                if (ref.get() != null) {
                    threadLocalDataList.set(j++, ref);
                }
            }
            for (int i = size - 1; i >= j; i--) {
                // A tail remove is inlined to a range change check and a decrement
                threadLocalDataList.remove(i);
            }
            reclaimedThreadLocalsUpdater.addAndGet(this, -1 * (size - j));
        }
    }

    private void freeInternal(ByteBuffer buffer) {
        if (closed) {
            DirectByteBufferDeallocator.free(buffer);
            return; //GC will take care of it
        }
        final ThreadLocalData local = threadLocalCache.get();
        if(local != null) {
            if(local.allocationDepth > 0) {
                local.allocationDepth--;
                if (local.buffers.size() < threadLocalCacheSize) {
                    local.buffers.add(buffer);
                    return;
                }
            }
        }
        queueIfUnderMax(buffer);
    }

    private void queueIfUnderMax(ByteBuffer buffer) {
        int size;
        do {
            size = currentQueueLength;
            if(size > maximumPoolSize) {
                DirectByteBufferDeallocator.free(buffer);
                return;
            }
        } while (!currentQueueLengthUpdater.compareAndSet(this, size, size + 1));
        queue.add(buffer);
    }

    @Override
    public void close() {
        if (closed) {
            return;
        }
        closed = true;
        queue.clear();

        synchronized (threadLocalDataList) {
            for (WeakReference ref : threadLocalDataList) {
                final ThreadLocalData local = ref.get();
                ref.clear();
                if (local != null) {
                    local.buffers.clear();
                    threadLocalCache.remove(local);
                }
            }
            threadLocalDataList.clear();
        }
    }

    @Override
    protected void finalize() throws Throwable {
        try {
            close();
        } finally {
            super.finalize();
        }
    }

    private static class DefaultPooledBuffer implements PooledByteBuffer {

        private final DefaultByteBufferPool pool;
        private final LeakDetector leakDetector;
        private ByteBuffer buffer;

        private volatile int referenceCount = 1;
        private static final AtomicIntegerFieldUpdater referenceCountUpdater = AtomicIntegerFieldUpdater.newUpdater(DefaultPooledBuffer.class, "referenceCount");

        DefaultPooledBuffer(DefaultByteBufferPool pool, ByteBuffer buffer, boolean detectLeaks) {
            this.pool = pool;
            this.buffer = buffer;
            this.leakDetector = detectLeaks ? new LeakDetector() : null;
        }

        @Override
        public ByteBuffer getBuffer() {
            final ByteBuffer tmp = this.buffer;
            //UNDERTOW-2072
            if (referenceCount == 0 || tmp == null) {
                throw UndertowMessages.MESSAGES.bufferAlreadyFreed();
            }
            return tmp;
        }

        @Override
        public void close() {
            final ByteBuffer tmp = this.buffer;
            if (referenceCountUpdater.compareAndSet(this, 1, 0)) {
                this.buffer = null;
                if (leakDetector != null) {
                    leakDetector.closed = true;
                }
                pool.freeInternal(tmp);
            }
        }

        @Override
        public boolean isOpen() {
            return referenceCount > 0;
        }

        @Override
        public String toString() {
            return "DefaultPooledBuffer{" +
                    "buffer=" + buffer +
                    ", referenceCount=" + referenceCount +
                    '}';
        }
    }

    private class ThreadLocalData {
        final ArrayDeque buffers = new ArrayDeque<>(threadLocalCacheSize);
        int allocationDepth = 0;

        @Override
        protected void finalize() throws Throwable {
            try {
                reclaimedThreadLocalsUpdater.incrementAndGet(DefaultByteBufferPool.this);
                if (buffers != null) {
                    // Recycle them
                    ByteBuffer buffer;
                    while ((buffer = buffers.poll()) != null) {
                        queueIfUnderMax(buffer);
                    }
                }
            } finally {
                super.finalize();
            }
        }
    }

    private static class LeakDetector {

        volatile boolean closed = false;
        private final Throwable allocationPoint;

        private LeakDetector() {
            this.allocationPoint = new Throwable("Buffer leak detected");
        }

        @Override
        protected void finalize() throws Throwable {
            try {
                if(!closed) {
                    allocationPoint.printStackTrace();
                }
            } finally {
                super.finalize();
            }
        }
    }

    // This is used instead of Java ThreadLocal class. Unlike in the ThreadLocal class, the remove() method in this
    // class can be called by a different thread than the one that initialized the data.
    private static class ThreadLocalCache {

        final Map localsByThread = Collections.synchronizedMap(new WeakHashMap<>());

        ThreadLocalData get() {
            return localsByThread.get(Thread.currentThread());
        }

        void set(ThreadLocalData threadLocalData) {
            localsByThread.put(Thread.currentThread(), threadLocalData);
        }

        void remove(ThreadLocalData threadLocalData) {
            // Find the entry containing given data instance and remove it from the map.
            for (Map.Entry entry: localsByThread.entrySet()) {
                if (threadLocalData.equals(entry.getValue())) {
                    localsByThread.remove(entry.getKey(), entry.getValue());
                    break;
                }
            }
        }
    }

}




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