netty5/buffer/src/main/java/io/netty/buffer/UnpooledUnsafeDirectByteBuf.java

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you 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.netty.buffer;

import io.netty.util.ResourceLeak;
import io.netty.util.internal.PlatformDependent;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.GatheringByteChannel;
import java.nio.channels.ScatteringByteChannel;
import java.util.ArrayDeque;
import java.util.Queue;

/**
 * A NIO {@link ByteBuffer} based buffer.  It is recommended to use {@link Unpooled#directBuffer(int)}
 * and {@link Unpooled#wrappedBuffer(ByteBuffer)} instead of calling the
 * constructor explicitly.
 */
final class UnpooledUnsafeDirectByteBuf extends AbstractReferenceCountedByteBuf {

    private static final boolean NATIVE_ORDER = ByteOrder.nativeOrder() == ByteOrder.BIG_ENDIAN;

    private final ResourceLeak leak = leakDetector.open(this);
    private final ByteBufAllocator alloc;

    private long memoryAddress;
    private ByteBuffer buffer;
    private ByteBuffer tmpNioBuf;
    private int capacity;
    private boolean doNotFree;
    private Queue<ByteBuffer> suspendedDeallocations;

    /**
     * Creates a new direct buffer.
     *
     * @param initialCapacity the initial capacity of the underlying direct buffer
     * @param maxCapacity     the maximum capacity of the underlying direct buffer
     */
    UnpooledUnsafeDirectByteBuf(ByteBufAllocator alloc, int initialCapacity, int maxCapacity) {
        super(maxCapacity);
        if (alloc == null) {
            throw new NullPointerException("alloc");
        }
        if (initialCapacity < 0) {
            throw new IllegalArgumentException("initialCapacity: " + initialCapacity);
        }
        if (maxCapacity < 0) {
            throw new IllegalArgumentException("maxCapacity: " + maxCapacity);
        }
        if (initialCapacity > maxCapacity) {
            throw new IllegalArgumentException(String.format(
                    "initialCapacity(%d) > maxCapacity(%d)", initialCapacity, maxCapacity));
        }

        this.alloc = alloc;
        setByteBuffer(ByteBuffer.allocateDirect(initialCapacity));
    }

    /**
     * Creates a new direct buffer by wrapping the specified initial buffer.
     *
     * @param maxCapacity the maximum capacity of the underlying direct buffer
     */
    UnpooledUnsafeDirectByteBuf(ByteBufAllocator alloc, ByteBuffer initialBuffer, int maxCapacity) {
        super(maxCapacity);
        if (alloc == null) {
            throw new NullPointerException("alloc");
        }
        if (initialBuffer == null) {
            throw new NullPointerException("initialBuffer");
        }
        if (!initialBuffer.isDirect()) {
            throw new IllegalArgumentException("initialBuffer is not a direct buffer.");
        }
        if (initialBuffer.isReadOnly()) {
            throw new IllegalArgumentException("initialBuffer is a read-only buffer.");
        }

        int initialCapacity = initialBuffer.remaining();
        if (initialCapacity > maxCapacity) {
            throw new IllegalArgumentException(String.format(
                    "initialCapacity(%d) > maxCapacity(%d)", initialCapacity, maxCapacity));
        }

        this.alloc = alloc;
        doNotFree = true;
        setByteBuffer(initialBuffer.slice().order(ByteOrder.BIG_ENDIAN));
        writerIndex(initialCapacity);
    }

    private void setByteBuffer(ByteBuffer buffer) {
        ByteBuffer oldBuffer = this.buffer;
        if (oldBuffer != null) {
            if (doNotFree) {
                doNotFree = false;
            } else {
                if (suspendedDeallocations == null) {
                    PlatformDependent.freeDirectBuffer(oldBuffer);
                } else {
                    suspendedDeallocations.add(oldBuffer);
                }
            }
        }

        this.buffer = buffer;
        memoryAddress = PlatformDependent.directBufferAddress(buffer);
        tmpNioBuf = null;
        capacity = buffer.remaining();
    }

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

    @Override
    public int capacity() {
        return capacity;
    }

    @Override
    public ByteBuf capacity(int newCapacity) {
        ensureAccessible();
        if (newCapacity < 0 || newCapacity > maxCapacity()) {
            throw new IllegalArgumentException("newCapacity: " + newCapacity);
        }

        int readerIndex = readerIndex();
        int writerIndex = writerIndex();

        int oldCapacity = capacity;
        if (newCapacity > oldCapacity) {
            ByteBuffer oldBuffer = buffer;
            ByteBuffer newBuffer = ByteBuffer.allocateDirect(newCapacity);
            oldBuffer.position(readerIndex).limit(writerIndex);
            newBuffer.position(readerIndex).limit(writerIndex);
            newBuffer.put(oldBuffer);
            newBuffer.clear();
            setByteBuffer(newBuffer);
        } else if (newCapacity < oldCapacity) {
            ByteBuffer oldBuffer = buffer;
            ByteBuffer newBuffer = ByteBuffer.allocateDirect(newCapacity);
            if (readerIndex < newCapacity) {
                if (writerIndex > newCapacity) {
                    writerIndex(writerIndex = newCapacity);
                }
                oldBuffer.position(readerIndex).limit(writerIndex);
                newBuffer.position(readerIndex).limit(writerIndex);
                newBuffer.put(oldBuffer);
                newBuffer.clear();
            } else {
                setIndex(newCapacity, newCapacity);
            }
            setByteBuffer(newBuffer);
        }
        return this;
    }

    @Override
    public ByteBufAllocator alloc() {
        return alloc;
    }

    @Override
    public ByteOrder order() {
        return ByteOrder.BIG_ENDIAN;
    }

    @Override
    public boolean hasArray() {
        return false;
    }

    @Override
    public byte[] array() {
        throw new UnsupportedOperationException("direct buffer");
    }

    @Override
    public int arrayOffset() {
        throw new UnsupportedOperationException("direct buffer");
    }

    @Override
    protected byte _getByte(int index) {
        return PlatformDependent.getByte(addr(index));
    }

    @Override
    protected short _getShort(int index) {
        short v = PlatformDependent.getShort(addr(index));
        return NATIVE_ORDER? v : Short.reverseBytes(v);
    }

    @Override
    protected int _getUnsignedMedium(int index) {
        long addr = addr(index);
        return (PlatformDependent.getByte(addr) & 0xff) << 16 |
                (PlatformDependent.getByte(addr + 1) & 0xff) << 8 |
                PlatformDependent.getByte(addr + 2) & 0xff;
    }

    @Override
    protected int _getInt(int index) {
        int v = PlatformDependent.getInt(addr(index));
        return NATIVE_ORDER? v : Integer.reverseBytes(v);
    }

    @Override
    protected long _getLong(int index) {
        long v = PlatformDependent.getLong(addr(index));
        return NATIVE_ORDER? v : Long.reverseBytes(v);
    }

    @Override
    public ByteBuf getBytes(int index, ByteBuf dst, int dstIndex, int length) {
        ensureAccessible();
        if (dst instanceof UnpooledUnsafeDirectByteBuf) {
            UnpooledUnsafeDirectByteBuf bbdst = (UnpooledUnsafeDirectByteBuf) dst;
            PlatformDependent.copyMemory(addr(index), bbdst.addr(dstIndex), length);
        } else if (dst.hasArray()) {
            PlatformDependent.copyMemory(addr(index), dst.array(), dst.arrayOffset() + dstIndex, length);
        } else {
            dst.setBytes(dstIndex, this, index, length);
        }
        return this;
    }

    @Override
    public ByteBuf getBytes(int index, byte[] dst, int dstIndex, int length) {
        checkIndex(index, length);
        if (dst == null) {
            throw new NullPointerException("dst");
        }
        if (dstIndex < 0 || dstIndex > dst.length - length) {
            throw new IndexOutOfBoundsException(String.format(
                    "dstIndex: %d, length: %d (expected: range(0, %d))", dstIndex, length, dst.length));
        }

        if (length != 0) {
            PlatformDependent.copyMemory(addr(index), dst, dstIndex, length);
        }
        return this;
    }

    @Override
    public ByteBuf getBytes(int index, ByteBuffer dst) {
        checkIndex(index);
        if (dst == null) {
            throw new NullPointerException("dst");
        }

        int bytesToCopy = Math.min(capacity() - index, dst.remaining());
        ByteBuffer tmpBuf = internalNioBuffer();
        tmpBuf.clear().position(index).limit(index + bytesToCopy);
        dst.put(tmpBuf);
        return this;
    }

    @Override
    protected void _setByte(int index, int value) {
        PlatformDependent.putByte(addr(index), (byte) value);
    }

    @Override
    protected void _setShort(int index, int value) {
        PlatformDependent.putShort(addr(index), NATIVE_ORDER ? (short) value : Short.reverseBytes((short) value));
    }

    @Override
    protected void _setMedium(int index, int value) {
        long addr = addr(index);
        PlatformDependent.putByte(addr, (byte) (value >>> 16));
        PlatformDependent.putByte(addr + 1, (byte) (value >>> 8));
        PlatformDependent.putByte(addr + 2, (byte) value);
    }

    @Override
    protected void _setInt(int index, int value) {
        PlatformDependent.putInt(addr(index), NATIVE_ORDER ? value : Integer.reverseBytes(value));
    }

    @Override
    protected void _setLong(int index, long value) {
        PlatformDependent.putLong(addr(index), NATIVE_ORDER ? value : Long.reverseBytes(value));
    }

    @Override
    public ByteBuf setBytes(int index, ByteBuf src, int srcIndex, int length) {
        ensureAccessible();
        if (src instanceof UnpooledUnsafeDirectByteBuf) {
            UnpooledUnsafeDirectByteBuf bbsrc = (UnpooledUnsafeDirectByteBuf) src;
            PlatformDependent.copyMemory(bbsrc.addr(srcIndex), addr(index), length);
        } else if (buffer.hasArray()) {
            PlatformDependent.copyMemory(src.array(), src.arrayOffset() + srcIndex, addr(index), length);
        } else {
            src.getBytes(srcIndex, this, index, length);
        }
        return this;
    }

    @Override
    public ByteBuf setBytes(int index, byte[] src, int srcIndex, int length) {
        checkIndex(index, length);
        if (length != 0) {
            PlatformDependent.copyMemory(src, srcIndex, addr(index), length);
        }
        return this;
    }

    @Override
    public ByteBuf setBytes(int index, ByteBuffer src) {
        ensureAccessible();
        ByteBuffer tmpBuf = internalNioBuffer();
        if (src == tmpBuf) {
            src = src.duplicate();
        }

        tmpBuf.clear().position(index).limit(index + src.remaining());
        tmpBuf.put(src);
        return this;
    }

    @Override
    public ByteBuf getBytes(int index, OutputStream out, int length) throws IOException {
        ensureAccessible();
        if (length != 0) {
            byte[] tmp = new byte[length];
            PlatformDependent.copyMemory(addr(index), tmp, 0, length);
            out.write(tmp);
        }
        return this;
    }

    @Override
    public int getBytes(int index, GatheringByteChannel out, int length) throws IOException {
        ensureAccessible();
        if (length == 0) {
            return 0;
        }

        ByteBuffer tmpBuf = internalNioBuffer();
        tmpBuf.clear().position(index).limit(index + length);
        return out.write(tmpBuf);
    }

    @Override
    public int setBytes(int index, InputStream in, int length) throws IOException {
        checkIndex(index, length);
        byte[] tmp = new byte[length];
        int readBytes = in.read(tmp);
        if (readBytes > 0) {
            PlatformDependent.copyMemory(tmp, 0, addr(index), readBytes);
        }
        return readBytes;
    }

    @Override
    public int setBytes(int index, ScatteringByteChannel in, int length) throws IOException {
        ensureAccessible();
        ByteBuffer tmpNioBuf = internalNioBuffer();
        tmpNioBuf.clear().position(index).limit(index + length);
        try {
            return in.read(tmpNioBuf);
        } catch (ClosedChannelException e) {
            return -1;
        }
    }

    @Override
    public int nioBufferCount() {
        return 1;
    }

    @Override
    public ByteBuffer nioBuffer(int index, int length) {
        ensureAccessible();
        if (index == 0 && length == capacity()) {
            return buffer.duplicate();
        } else {
            return ((ByteBuffer) internalNioBuffer().clear().position(index).limit(index + length)).slice();
        }
    }

    @Override
    public ByteBuffer[] nioBuffers(int index, int length) {
        return new ByteBuffer[] { nioBuffer(index, length) };
    }

    @Override
    public ByteBuf copy(int index, int length) {
        checkIndex(index, length);
        UnpooledUnsafeDirectByteBuf copy =
                (UnpooledUnsafeDirectByteBuf) alloc().directBuffer(capacity(), maxCapacity());
        if (length != 0) {
            PlatformDependent.copyMemory(addr(index), copy.addr(index), length);
            copy.setIndex(index, index + length);
        }
        return copy;
    }

    private ByteBuffer internalNioBuffer() {
        ByteBuffer tmpNioBuf = this.tmpNioBuf;
        if (tmpNioBuf == null) {
            this.tmpNioBuf = tmpNioBuf = buffer.duplicate();
        }
        return tmpNioBuf;
    }

    @Override
    protected void deallocate() {
        ByteBuffer buffer = this.buffer;
        if (buffer == null) {
            return;
        }

        this.buffer = null;

        resumeIntermediaryDeallocations();
        if (!doNotFree) {
            PlatformDependent.freeDirectBuffer(buffer);
        }
        leak.close();
    }

    @Override
    public ByteBuf suspendIntermediaryDeallocations() {
        ensureAccessible();
        if (suspendedDeallocations == null) {
            suspendedDeallocations = new ArrayDeque<ByteBuffer>(2);
        }
        return this;
    }

    @Override
    public ByteBuf resumeIntermediaryDeallocations() {
        if (suspendedDeallocations == null) {
            return this;
        }

        Queue<ByteBuffer> suspendedDeallocations = this.suspendedDeallocations;
        this.suspendedDeallocations = null;

        for (ByteBuffer buf: suspendedDeallocations) {
            PlatformDependent.freeDirectBuffer(buf);
        }
        return this;
    }

    @Override
    public ByteBuf unwrap() {
        return null;
    }

    private long addr(int index) {
        return memoryAddress + index;
    }
}