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/*
 * 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.handler.stream;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.FileRegion;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;

/**
 * A {@link ChunkedInput} that fetches data from a file chunk by chunk.
 * 

* If your operating system supports * zero-copy file transfer * such as {@code sendfile()}, you might want to use {@link FileRegion} instead. */ public class ChunkedFile implements ChunkedInput { private final RandomAccessFile file; 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 ChunkedFile(File file) throws IOException { this(file, ChunkedStream.DEFAULT_CHUNK_SIZE); } /** * 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 ChunkedFile(File file, int chunkSize) throws IOException { this(new RandomAccessFile(file, "r"), chunkSize); } /** * Creates a new instance that fetches data from the specified file. */ public ChunkedFile(RandomAccessFile file) throws IOException { this(file, ChunkedStream.DEFAULT_CHUNK_SIZE); } /** * 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 ChunkedFile(RandomAccessFile file, int chunkSize) throws IOException { this(file, 0, file.length(), chunkSize); } /** * Creates a new instance that fetches data from the specified file. * * @param offset the offset of the file where the transfer begins * @param length the number of bytes to transfer * @param chunkSize the number of bytes to fetch on each * {@link #readChunk(ChannelHandlerContext)} call */ public ChunkedFile(RandomAccessFile file, long offset, long length, int chunkSize) throws IOException { if (file == null) { throw new NullPointerException("file"); } if (offset < 0) { throw new IllegalArgumentException( "offset: " + offset + " (expected: 0 or greater)"); } if (length < 0) { throw new IllegalArgumentException( "length: " + length + " (expected: 0 or greater)"); } if (chunkSize <= 0) { throw new IllegalArgumentException( "chunkSize: " + chunkSize + " (expected: a positive integer)"); } this.file = file; this.offset = startOffset = offset; endOffset = offset + length; this.chunkSize = chunkSize; file.seek(offset); } /** * Returns the offset in the file where the transfer began. */ public long startOffset() { return startOffset; } /** * Returns the offset in the file where the transfer will end. */ public long endOffset() { return endOffset; } /** * Returns the offset in the file where the transfer is happening currently. */ public long currentOffset() { return offset; } @Override public boolean isEndOfInput() throws Exception { return !(offset < endOffset && file.getChannel().isOpen()); } @Override public void close() throws Exception { file.close(); } @Deprecated @Override public ByteBuf readChunk(ChannelHandlerContext ctx) throws Exception { return readChunk(ctx.alloc()); } @Override public ByteBuf readChunk(ByteBufAllocator allocator) throws Exception { long offset = this.offset; if (offset >= endOffset) { return null; } int chunkSize = (int) Math.min(this.chunkSize, endOffset - offset); // Check if the buffer is backed by an byte array. If so we can optimize it a bit an safe a copy ByteBuf buf = allocator.heapBuffer(chunkSize); boolean release = true; try { file.readFully(buf.array(), buf.arrayOffset(), chunkSize); buf.writerIndex(chunkSize); this.offset = offset + chunkSize; release = false; return buf; } finally { if (release) { buf.release(); } } } @Override public long length() { return endOffset - startOffset; } @Override public long progress() { return offset - startOffset; } }





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