SharedInputBuffer.java
/**
* 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.
*/
package org.apache.cxf.transport.http.asyncclient.hc5;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.nio.ByteBuffer;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.hc.core5.http.impl.nio.ExpandableBuffer;
/**
* Content buffer 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 expect to transfer data from {@link ByteBuffer} to the buffer
* by calling {@link #consumeContent(ByteBuffer)}.
* <p/>
* The worker thread is expected to read the data from the buffer by calling
* {@link #read()} or {@link #read(byte[], int, int)} methods.
* <p/>
* In case of an abnormal situation or when no longer needed the buffer must be shut down
* using {@link #shutdown()} method.
*/
public class SharedInputBuffer extends ExpandableBuffer {
private final ReentrantLock lock;
private final Condition condition;
private final Condition suspendInput;
private volatile boolean shutdown;
private volatile boolean endOfStream;
private volatile ByteBuffer waitingBuffer;
public SharedInputBuffer(int buffersize) {
super(buffersize);
this.lock = new ReentrantLock();
this.condition = this.lock.newCondition();
this.suspendInput = this.lock.newCondition();
}
public void reset() {
if (this.shutdown) {
return;
}
this.lock.lock();
try {
clear();
this.endOfStream = false;
} finally {
this.lock.unlock();
}
}
public int consumeContent(final ByteBuffer buffer, boolean last) throws IOException {
if (this.shutdown) {
return -1;
}
this.lock.lock();
try {
setInputMode();
int totalRead = 0;
int bytesRead;
if (waitingBuffer != null && buffer().position() == 0) {
while ((bytesRead = transfer(buffer, this.waitingBuffer)) > 0) {
totalRead += bytesRead;
}
}
//read more
while ((bytesRead = transfer(buffer)) > 0) {
totalRead += bytesRead;
}
if (last) {
this.endOfStream = true;
}
if (!buffer().hasRemaining() && !this.endOfStream) {
try {
suspendInput.await();
} catch (InterruptedException ex) {
throw new IOException("Interrupted while waiting buffer to be drained ");
}
}
this.condition.signalAll();
if (totalRead > 0) {
return totalRead;
}
if (this.endOfStream) {
return -1;
}
return 0;
} finally {
this.lock.unlock();
}
}
@Override
public boolean hasData() {
this.lock.lock();
try {
return super.hasData();
} 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();
}
}
protected void waitForData(int waitPos) throws IOException {
this.lock.lock();
try {
try {
while (true) {
if (this.waitingBuffer != null && this.waitingBuffer.position() > waitPos) {
return;
}
if (super.hasData()) {
return;
}
if (this.endOfStream) {
return;
}
if (this.shutdown) {
throw new InterruptedIOException("Input operation aborted");
}
this.suspendInput.signalAll();
this.condition.await();
}
} catch (InterruptedException ex) {
throw new IOException("Interrupted while waiting for more data");
}
} finally {
this.lock.unlock();
}
}
public void close() {
if (this.shutdown) {
return;
}
this.endOfStream = true;
this.lock.lock();
try {
this.condition.signalAll();
} finally {
this.lock.unlock();
}
}
public void shutdown() {
if (this.shutdown) {
return;
}
this.shutdown = true;
this.lock.lock();
try {
this.condition.signalAll();
} finally {
this.lock.unlock();
}
}
protected boolean isShutdown() {
return this.shutdown;
}
protected boolean isEndOfStream() {
return this.shutdown || (!hasData() && this.endOfStream);
}
public int read() throws IOException {
if (this.shutdown) {
return -1;
}
this.lock.lock();
try {
if (!super.hasData()) {
waitForData(0);
}
if (isEndOfStream()) {
return -1;
}
setOutputMode();
return buffer().get() & 0xff;
} finally {
this.lock.unlock();
}
}
public int read(final byte[] b, int off, int len) throws IOException {
if (this.shutdown) {
return -1;
}
if (b == null) {
return 0;
}
this.lock.lock();
try {
if (!hasData()) {
this.waitingBuffer = ByteBuffer.wrap(b, off, len);
waitForData(off);
int i = waitingBuffer.position() - off;
waitingBuffer = null;
if (i > 0) {
//++waitCnt;
return i;
}
}
if (isEndOfStream()) {
return -1;
}
setOutputMode();
int chunk = len;
if (chunk > buffer().remaining()) {
chunk = buffer().remaining();
}
buffer().get(b, off, chunk);
return chunk;
} finally {
this.lock.unlock();
}
}
public int read(final byte[] b) throws IOException {
if (this.shutdown) {
return -1;
}
if (b == null) {
return 0;
}
return read(b, 0, b.length);
}
private int transfer(ByteBuffer from, ByteBuffer to) {
int transfer = Math.min(to.remaining(), from.remaining());
if (from.remaining() == 0) {
return -1;
}
if (transfer == 0) {
return transfer;
}
// use a duplicated buffer so we don't disrupt the limit of the original buffer
final ByteBuffer tmp = from.duplicate();
tmp.limit(tmp.position() + transfer);
to.put(tmp);
// now discard the data we've copied from the original source (optional)
from.position(from.position() + transfer);
return transfer;
}
private int transfer(ByteBuffer from) {
ensureCapacity(from);
return transfer(from, buffer());
}
private void ensureCapacity(ByteBuffer source) {
if (buffer().remaining() >= source.remaining()) {
return;
} else {
final int adjustment = source.remaining() - buffer().remaining();
ensureCapacity(buffer().capacity() + adjustment);
}
}
}