/*
* 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.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.
* <p>
* If your operating system supports
* <a href="http://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 ChunkedFile implements ChunkedInput<ByteBuf> {
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();
}
@Override
public ByteBuf readChunk(ChannelHandlerContext ctx) 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 = ctx.alloc().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();
}
}
}
}