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// 
// ========================================================================
// Copyright (c) 1995-2022 Mort Bay Consulting Pty Ltd and others.
// ------------------------------------------------------------------------
// 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.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.IntConsumer;
import org.eclipse.jetty.util.BufferUtil;

/**
 *  A {@link ByteBuffer} pool.
 *  Acquired buffers may be {@link #release(ByteBuffer) released} but they do not need to;
 *  if they are released, they may be recycled and reused, otherwise they will be garbage
 *  collected as usual.
 *
 * @deprecated The Eclipse Jetty and Apache Felix Http Jetty packages are no longer supported.
 */
@Deprecated(since = "2021-05-27")
public interface ByteBufferPool {

    /**
     * Requests a {@link ByteBuffer} of the given size.
     * The returned buffer may have a bigger capacity than the size being
     * requested but it will have the limit set to the given size.
     *
     * @param size the size of the buffer
     * @param direct whether the buffer must be direct or not
     * @return the requested buffer
     * @see #release(ByteBuffer)
     */
    ByteBuffer acquire(int size, boolean direct);

    /**
     * Returns a {@link ByteBuffer}, usually obtained with {@link #acquire(int, boolean)}
     * (but not necessarily), making it available for recycling and reuse.
     *
     * @param buffer the buffer to return
     * @see #acquire(int, boolean)
     */
    void release(ByteBuffer buffer);

    /**
     * Removes a {@link ByteBuffer} that was previously obtained with {@link #acquire(int, boolean)}.
     * The buffer will not be available for further reuse.
     *
     * @param buffer the buffer to remove
     * @see #acquire(int, boolean)
     * @see #release(ByteBuffer)
     */
    default void remove(ByteBuffer buffer) {
    }

    /**
     * Creates a new ByteBuffer of the given capacity and the given directness.
     *
     * @param capacity the ByteBuffer capacity
     * @param direct the ByteBuffer directness
     * @return a newly allocated ByteBuffer
     */
    default ByteBuffer newByteBuffer(int capacity, boolean direct) {
        return direct ? BufferUtil.allocateDirect(capacity) : BufferUtil.allocate(capacity);
    }

    // @deprecated The Eclipse Jetty and Apache Felix Http Jetty packages are no longer supported.
    @Deprecated(since = "2021-05-27")
    class Lease {

        private final ByteBufferPool byteBufferPool;

        private final List buffers;

        private final List recycles;

        public Lease(ByteBufferPool byteBufferPool) {
            this.byteBufferPool = byteBufferPool;
            this.buffers = new ArrayList<>();
            this.recycles = new ArrayList<>();
        }

        public ByteBuffer acquire(int capacity, boolean direct) {
            ByteBuffer buffer = byteBufferPool.acquire(capacity, direct);
            BufferUtil.clearToFill(buffer);
            return buffer;
        }

        public void append(ByteBuffer buffer, boolean recycle) {
            buffers.add(buffer);
            recycles.add(recycle);
        }

        public void insert(int index, ByteBuffer buffer, boolean recycle) {
            buffers.add(index, buffer);
            recycles.add(index, recycle);
        }

        public List getByteBuffers() {
            return buffers;
        }

        public long getTotalLength() {
            long length = 0;
            for (ByteBuffer buffer : buffers) {
                length += buffer.remaining();
            }
            return length;
        }

        public int getSize() {
            return buffers.size();
        }

        public void recycle() {
            for (int i = 0; i < buffers.size(); ++i) {
                ByteBuffer buffer = buffers.get(i);
                if (recycles.get(i))
                    release(buffer);
            }
            buffers.clear();
            recycles.clear();
        }

        public void release(ByteBuffer buffer) {
            byteBufferPool.release(buffer);
        }
    }

    // @deprecated The Eclipse Jetty and Apache Felix Http Jetty packages are no longer supported.
    @Deprecated(since = "2021-05-27")
    class Bucket {

        private final Queue _queue = new ConcurrentLinkedQueue<>();

        private final ByteBufferPool _pool;

        private final int _capacity;

        private final int _maxSize;

        private final AtomicInteger _size;

        private final AtomicLong _lastUpdate = new AtomicLong(System.nanoTime());

        private final IntConsumer _memoryFunction;

        @Deprecated
        public Bucket(ByteBufferPool pool, int capacity, int maxSize) {
            this(pool, capacity, maxSize, i -> {
            });
        }

        public Bucket(ByteBufferPool pool, int capacity, int maxSize, IntConsumer memoryFunction) {
            _pool = pool;
            _capacity = capacity;
            _maxSize = maxSize;
            _size = maxSize > 0 ? new AtomicInteger() : null;
            _memoryFunction = Objects.requireNonNull(memoryFunction);
        }

        public ByteBuffer acquire() {
            ByteBuffer buffer = _queue.poll();
            if (buffer != null) {
                if (_size != null)
                    _size.decrementAndGet();
                _memoryFunction.accept(-buffer.capacity());
            }
            return buffer;
        }

        /**
         * @param direct whether to create a direct buffer when none is available
         * @return a ByteBuffer
         * @deprecated use {@link #acquire()} instead
         */
        @Deprecated
        public ByteBuffer acquire(boolean direct) {
            ByteBuffer buffer = acquire();
            if (buffer == null)
                return _pool.newByteBuffer(_capacity, direct);
            return buffer;
        }

        public void release(ByteBuffer buffer) {
            resetUpdateTime();
            BufferUtil.reset(buffer);
            if (_size == null || _size.incrementAndGet() <= _maxSize) {
                _queue.offer(buffer);
                _memoryFunction.accept(buffer.capacity());
            } else {
                _size.decrementAndGet();
            }
        }

        void resetUpdateTime() {
            _lastUpdate.lazySet(System.nanoTime());
        }

        public void clear() {
            int size = _size == null ? 0 : _size.get() - 1;
            while (size >= 0) {
                ByteBuffer buffer = acquire();
                if (buffer == null)
                    break;
                if (_size != null)
                    --size;
            }
        }

        boolean isEmpty() {
            return _queue.isEmpty();
        }

        int size() {
            return _queue.size();
        }

        long getLastUpdate() {
            return _lastUpdate.get();
        }

        @Override
        public String toString() {
            return String.format("%s@%x{capacity=%d, size=%d, maxSize=%d}", getClass().getSimpleName(), hashCode(), _capacity, size(), _maxSize);
        }
    }
}