/*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apach3.http.nio.util;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import org.apach3.http.annotation.ThreadSafe;
import org.apach3.http.nio.ContentEncoder;
import org.apach3.http.nio.IOControl;
/**
* Implementation of the {@link ContentOutputBuffer} interface that can be
* shared by multiple threads, usually the I/O dispatch of an I/O reactor and
* a worker thread.
* <p>
* The I/O dispatch thread is expected to transfer data from the buffer to
* {@link ContentEncoder} by calling {@link #produceContent(ContentEncoder)}.
* <p>
* The worker thread is expected to write data to the buffer by calling
* {@link #write(int)}, {@link #write(byte[], int, int)} or {@link #writeCompleted()}
* <p>
* In case of an abnormal situation or when no longer needed the buffer must be
* shut down using {@link #shutdown()} method.
*
* @since 4.0
*/
@ThreadSafe
public class SharedOutputBuffer extends ExpandableBuffer implements ContentOutputBuffer {
private final IOControl ioctrl;
private final ReentrantLock lock;
private final Condition condition;
private volatile boolean shutdown = false;
private volatile boolean endOfStream = false;
public SharedOutputBuffer(int buffersize, final IOControl ioctrl, final ByteBufferAllocator allocator) {
super(buffersize, allocator);
if (ioctrl == null) {
throw new IllegalArgumentException("I/O content control may not be null");
}
this.ioctrl = ioctrl;
this.lock = new ReentrantLock();
this.condition = this.lock.newCondition();
}
public void reset() {
if (this.shutdown) {
return;
}
this.lock.lock();
try {
clear();
this.endOfStream = false;
} finally {
this.lock.unlock();
}
}
@Override
public boolean hasData() {
this.lock.lock();
try {
return super.hasData();
} finally {
this.lock.unlock();
}
}
@Override
public int available() {
this.lock.lock();
try {
return super.available();
} finally {
this.lock.unlock();
}
}
@Override
public int capacity() {
this.lock.lock();
try {
return super.capacity();
} finally {
this.lock.unlock();
}
}
@Override
public int length() {
this.lock.lock();
try {
return super.length();
} finally {
this.lock.unlock();
}
}
public int produceContent(final ContentEncoder encoder) throws IOException {
if (this.shutdown) {
return -1;
}
this.lock.lock();
try {
setOutputMode();
int bytesWritten = 0;
if (super.hasData()) {
bytesWritten = encoder.write(this.buffer);
if (encoder.isCompleted()) {
this.endOfStream = true;
}
}
if (!super.hasData()) {
// No more buffered content
// If at the end of the stream, terminate
if (this.endOfStream && !encoder.isCompleted()) {
encoder.complete();
}
if (!this.endOfStream) {
// suspend output events
this.ioctrl.suspendOutput();
}
}
this.condition.signalAll();
return bytesWritten;
} finally {
this.lock.unlock();
}
}
public void close() {
shutdown();
}
public void shutdown() {
if (this.shutdown) {
return;
}
this.shutdown = true;
this.lock.lock();
try {
this.condition.signalAll();
} finally {
this.lock.unlock();
}
}
public void write(final byte[] b, int off, int len) throws IOException {
if (b == null) {
return;
}
this.lock.lock();
try {
if (this.shutdown || this.endOfStream) {
throw new IllegalStateException("Buffer already closed for writing");
}
setInputMode();
int remaining = len;
while (remaining > 0) {
if (!this.buffer.hasRemaining()) {
flushContent();
setInputMode();
}
int chunk = Math.min(remaining, this.buffer.remaining());
this.buffer.put(b, off, chunk);
remaining -= chunk;
off += chunk;
}
} finally {
this.lock.unlock();
}
}
public void write(final byte[] b) throws IOException {
if (b == null) {
return;
}
write(b, 0, b.length);
}
public void write(int b) throws IOException {
this.lock.lock();
try {
if (this.shutdown || this.endOfStream) {
throw new IllegalStateException("Buffer already closed for writing");
}
setInputMode();
if (!this.buffer.hasRemaining()) {
flushContent();
setInputMode();
}
this.buffer.put((byte)b);
} finally {
this.lock.unlock();
}
}
public void flush() throws IOException {
}
private void flushContent() throws IOException {
this.lock.lock();
try {
try {
while (super.hasData()) {
if (this.shutdown) {
throw new InterruptedIOException("Output operation aborted");
}
this.ioctrl.requestOutput();
this.condition.await();
}
} catch (InterruptedException ex) {
throw new IOException("Interrupted while flushing the content buffer");
}
} finally {
this.lock.unlock();
}
}
public void writeCompleted() throws IOException {
this.lock.lock();
try {
if (this.endOfStream) {
return;
}
this.endOfStream = true;
this.ioctrl.requestOutput();
} finally {
this.lock.unlock();
}
}
}