org.glowroot.shaded.netty.channel.DefaultFileRegion Maven / Gradle / Ivy
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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 org.glowroot.shaded.netty.channel;
import org.glowroot.shaded.netty.util.AbstractReferenceCounted;
import org.glowroot.shaded.netty.util.IllegalReferenceCountException;
import org.glowroot.shaded.netty.util.internal.logging.InternalLogger;
import org.glowroot.shaded.netty.util.internal.logging.InternalLoggerFactory;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import java.nio.channels.WritableByteChannel;
/**
* Default {@link FileRegion} implementation which transfer data from a {@link FileChannel} or {@link File}.
*
* Be aware that the {@link FileChannel} will be automatically closed once {@link #refCnt()} returns
* {@code 0}.
*/
public class DefaultFileRegion extends AbstractReferenceCounted implements FileRegion {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(DefaultFileRegion.class);
private final File f;
private final long position;
private final long count;
private long transfered;
private FileChannel file;
/**
* Create a new instance
*
* @param file the {@link FileChannel} which should be transfered
* @param position the position from which the transfer should start
* @param count the number of bytes to transfer
*/
public DefaultFileRegion(FileChannel file, long position, long count) {
if (file == null) {
throw new NullPointerException("file");
}
if (position < 0) {
throw new IllegalArgumentException("position must be >= 0 but was " + position);
}
if (count < 0) {
throw new IllegalArgumentException("count must be >= 0 but was " + count);
}
this.file = file;
this.position = position;
this.count = count;
f = null;
}
/**
* Create a new instance using the given {@link File}. The {@link File} will be opened lazily or
* explicitly via {@link #open()}.
*
* @param f the {@link File} which should be transfered
* @param position the position from which the transfer should start
* @param count the number of bytes to transfer
*/
public DefaultFileRegion(File f, long position, long count) {
if (f == null) {
throw new NullPointerException("f");
}
if (position < 0) {
throw new IllegalArgumentException("position must be >= 0 but was " + position);
}
if (count < 0) {
throw new IllegalArgumentException("count must be >= 0 but was " + count);
}
this.position = position;
this.count = count;
this.f = f;
}
/**
* Returns {@code true} if the {@link FileRegion} has a open file-descriptor
*/
public boolean isOpen() {
return file != null;
}
/**
* Explicitly open the underlying file-descriptor if not done yet.
*/
public void open() throws IOException {
if (!isOpen() && refCnt() > 0) {
// Only open if this DefaultFileRegion was not released yet.
file = new RandomAccessFile(f, "r").getChannel();
}
}
@Override
public long position() {
return position;
}
@Override
public long count() {
return count;
}
@Override
public long transfered() {
return transfered;
}
@Override
public long transferTo(WritableByteChannel target, long position) throws IOException {
long count = this.count - position;
if (count < 0 || position < 0) {
throw new IllegalArgumentException(
"position out of range: " + position +
" (expected: 0 - " + (this.count - 1) + ')');
}
if (count == 0) {
return 0L;
}
if (refCnt() == 0) {
throw new IllegalReferenceCountException(0);
}
// Call open to make sure fc is initialized. This is a no-oop if we called it before.
open();
long written = file.transferTo(this.position + position, count, target);
if (written > 0) {
transfered += written;
}
return written;
}
@Override
protected void deallocate() {
FileChannel file = this.file;
if (file == null) {
return;
}
this.file = null;
try {
file.close();
} catch (IOException e) {
if (logger.isWarnEnabled()) {
logger.warn("Failed to close a file.", e);
}
}
}
}