ChunkedNioFile.java — netty Source File

Source Code

/*
 * 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:
 *
 *   https://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.handler.stream;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.FileRegion;
import io.netty.util.internal.ObjectUtil;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.FileChannel;

/**
 * A {@link ChunkedInput} that fetches data from a file chunk by chunk using
 * NIO {@link FileChannel}.
 * <p>
 * If your operating system supports
 * <a href="https://en.wikipedia.org/wiki/Zero-copy">zero-copy file transfer</a>
 * such as {@code sendfile()}, you might want to use {@link FileRegion} instead.
 */
public class ChunkedNioFile implements ChunkedInput<ByteBuf> {

    private final FileChannel in;
    private final long startOffset;
    private final long endOffset;
    private final int chunkSize;
    private long offset;

    /**
     * Creates a new instance that fetches data from the specified file.
     */
    public ChunkedNioFile(File in) throws IOException {
        this(new RandomAccessFile(in, "r").getChannel());
    }

    /**
     * Creates a new instance that fetches data from the specified file.
     *
     * @param chunkSize the number of bytes to fetch on each
     *                  {@link #readChunk(ChannelHandlerContext)} call
     */
    public ChunkedNioFile(File in, int chunkSize) throws IOException {
        this(new RandomAccessFile(in, "r").getChannel(), chunkSize);
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