/*
 * 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 java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.ReadOnlyBufferException;
import java.nio.channels.GatheringByteChannel;
import java.nio.channels.ScatteringByteChannel;

/**
 * A derived buffer which forbids any write requests to its parent.  It is
 * recommended to use {@link Unpooled#unmodifiableBuffer(ByteBuf)}
 * instead of calling the constructor explicitly.
 */
public class ReadOnlyByteBuf extends AbstractDerivedByteBuf {

    private final ByteBuf buffer;

    public ReadOnlyByteBuf(ByteBuf buffer) {
        super(buffer.maxCapacity());

        if (buffer instanceof ReadOnlyByteBuf || buffer instanceof DuplicatedByteBuf) {
            this.buffer = buffer.unwrap();
        } else {
            this.buffer = buffer;
        }
        setIndex(buffer.readerIndex(), buffer.writerIndex());
    }

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

    @Override
    public boolean isWritable(int numBytes) {
        return false;
    }

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

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

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

    @Override
    public boolean isDirect() {
        return buffer.isDirect();
    }

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

    @Override
    public byte[] array() {
        throw new ReadOnlyBufferException();
    }

    @Override
    public int arrayOffset() {
        throw new ReadOnlyBufferException();
    }

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

    @Override
    public long memoryAddress() {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf discardReadBytes() {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setBytes(int index, ByteBuf src, int srcIndex, int length) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setBytes(int index, byte[] src, int srcIndex, int length) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setBytes(int index, ByteBuffer src) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setByte(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    protected void _setByte(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setShort(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    protected void _setShort(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setMedium(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    protected void _setMedium(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setInt(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    protected void _setInt(int index, int value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public ByteBuf setLong(int index, long value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    protected void _setLong(int index, long value) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public int setBytes(int index, InputStream in, int length) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public int setBytes(int index, ScatteringByteChannel in, int length) {
        throw new ReadOnlyBufferException();
    }

    @Override
    public int getBytes(int index, GatheringByteChannel out, int length)
            throws IOException {
        return buffer.getBytes(index, out, length);
    }

    @Override
    public ByteBuf getBytes(int index, OutputStream out, int length)
            throws IOException {
        buffer.getBytes(index, out, length);
        return this;
    }

    @Override
    public ByteBuf getBytes(int index, byte[] dst, int dstIndex, int length) {
        buffer.getBytes(index, dst, dstIndex, length);
        return this;
    }

    @Override
    public ByteBuf getBytes(int index, ByteBuf dst, int dstIndex, int length) {
        buffer.getBytes(index, dst, dstIndex, length);
        return this;
    }

    @Override
    public ByteBuf getBytes(int index, ByteBuffer dst) {
        buffer.getBytes(index, dst);
        return this;
    }

    @Override
    public ByteBuf duplicate() {
        return new ReadOnlyByteBuf(this);
    }

    @Override
    public ByteBuf copy(int index, int length) {
        return buffer.copy(index, length);
    }

    @Override
    public ByteBuf slice(int index, int length) {
        return Unpooled.unmodifiableBuffer(buffer.slice(index, length));
    }

    @Override
    public byte getByte(int index) {
        return _getByte(index);
    }

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

    @Override
    public short getShort(int index) {
        return _getShort(index);
    }

    @Override
    protected short _getShort(int index) {
        return buffer.getShort(index);
    }

    @Override
    public int getUnsignedMedium(int index) {
        return _getUnsignedMedium(index);
    }

    @Override
    protected int _getUnsignedMedium(int index) {
        return buffer.getUnsignedMedium(index);
    }

    @Override
    public int getInt(int index) {
        return _getInt(index);
    }

    @Override
    protected int _getInt(int index) {
        return buffer.getInt(index);
    }

    @Override
    public long getLong(int index) {
        return _getLong(index);
    }

    @Override
    protected long _getLong(int index) {
        return buffer.getLong(index);
    }

    @Override
    public int nioBufferCount() {
        return buffer.nioBufferCount();
    }

    @Override
    public ByteBuffer nioBuffer(int index, int length) {
        return buffer.nioBuffer(index, length).asReadOnlyBuffer();
    }

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

    @Override
    public ByteBuffer internalNioBuffer(int index, int length) {
        return nioBuffer(index, length);
    }

    @Override
    public int forEachByte(int index, int length, ByteBufProcessor processor) {
        return buffer.forEachByte(index, length, processor);
    }

    @Override
    public int forEachByteDesc(int index, int length, ByteBufProcessor processor) {
        return buffer.forEachByteDesc(index, length, processor);
    }

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

    @Override
    public ByteBuf capacity(int newCapacity) {
        throw new ReadOnlyBufferException();
    }
}
