org.xnio.streams.BufferPipeInputStream Maven / Gradle / Ivy
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* Copyright 2010, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.xnio.streams;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InterruptedIOException;
import java.nio.ByteBuffer;
import java.util.ArrayDeque;
import java.util.Queue;
import java.util.concurrent.Semaphore;
import org.xnio.Buffers;
import org.xnio.Pooled;
/**
* An {@code InputStream} implementation which is populated asynchronously with {@link ByteBuffer} instances.
*/
public class BufferPipeInputStream extends InputStream {
private final Queue> queue;
private final InputHandler inputHandler;
// protected by "this"
private boolean eof;
private IOException failure;
/**
* Construct a new instance. The given {@code inputHandler} will
* be invoked after each buffer is fully read and when the stream is closed.
*
* @param inputHandler the input events handler
*/
public BufferPipeInputStream(final InputHandler inputHandler) {
this.inputHandler = inputHandler;
queue = new ArrayDeque>();
}
/**
* Push a buffer into the queue. There is no mechanism to limit the number of pushed buffers; if such a mechanism
* is desired, it must be implemented externally, for example maybe using a {@link Semaphore}.
*
* @param buffer the buffer from which more data should be read
*/
public void push(final ByteBuffer buffer) {
synchronized (this) {
if (buffer.hasRemaining() && !eof && failure == null) {
queue.add(Buffers.pooledWrapper(buffer));
notifyAll();
}
}
}
/**
* Push a buffer into the queue. There is no mechanism to limit the number of pushed buffers; if such a mechanism
* is desired, it must be implemented externally, for example maybe using a {@link Semaphore}.
*
* @param pooledBuffer the buffer from which more data should be read
*/
public void push(final Pooled pooledBuffer) {
synchronized (this) {
if (pooledBuffer.getResource().hasRemaining() && !eof && failure == null) {
queue.add(pooledBuffer);
notifyAll();
} else {
pooledBuffer.free();
}
}
}
/**
* Push an exception condition into the queue. After this method is called, no further buffers may be pushed into this
* instance.
*
* @param e the exception to push
*/
public void pushException(IOException e) {
synchronized (this) {
if (! eof) {
failure = e;
notifyAll();
}
}
}
/**
* Push the EOF condition into the queue. After this method is called, no further buffers may be pushed into this
* instance.
*/
public void pushEof() {
synchronized (this) {
eof = true;
notifyAll();
}
}
/** {@inheritDoc} */
public int read() throws IOException {
final Queue> queue = this.queue;
synchronized (this) {
while (queue.isEmpty()) {
if (eof) {
return -1;
}
checkFailure();
try {
wait();
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new InterruptedIOException("Interrupted on read()");
}
}
final Pooled entry = queue.peek();
final ByteBuffer buf = entry.getResource();
final int v = buf.get() & 0xff;
if (buf.remaining() == 0) {
queue.poll();
try {
inputHandler.acknowledge(entry);
} catch (IOException e) {
// no operation!
} finally {
entry.free();
}
}
return v;
}
}
private void clearQueue() {
synchronized (this) {
Pooled entry;
while ((entry = queue.poll()) != null) {
entry.free();
}
}
}
/** {@inheritDoc} */
public int read(final byte[] b, int off, int len) throws IOException {
if (len == 0) {
return 0;
}
final Queue> queue = this.queue;
synchronized (this) {
while (queue.isEmpty()) {
if (eof) {
return -1;
}
checkFailure();
try {
wait();
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new InterruptedIOException("Interrupted on read()");
}
}
int total = 0;
while (len > 0) {
final Pooled entry = queue.peek();
if (entry == null) {
break;
}
final ByteBuffer buffer = entry.getResource();
final int byteCnt = Math.min(buffer.remaining(), len);
buffer.get(b, off, byteCnt);
off += byteCnt;
total += byteCnt;
len -= byteCnt;
if (buffer.remaining() == 0) {
queue.poll();
try {
inputHandler.acknowledge(entry);
} catch (IOException e) {
// no operation!
} finally {
entry.free();
}
}
}
return total;
}
}
/** {@inheritDoc} */
public int available() throws IOException {
synchronized (this) {
int total = 0;
for (Pooled entry : queue) {
total += entry.getResource().remaining();
if (total < 0) {
return Integer.MAX_VALUE;
}
}
return total;
}
}
public long skip(long qty) throws IOException {
final Queue> queue = this.queue;
synchronized (this) {
while (queue.isEmpty()) {
if (eof) {
return 0L;
}
checkFailure();
try {
wait();
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new InterruptedIOException("Interrupted on read()");
}
}
long skipped = 0L;
while (qty > 0L) {
final Pooled entry = queue.peek();
if (entry == null) {
break;
}
final ByteBuffer buffer = entry.getResource();
final int byteCnt = Math.min(buffer.remaining(), (int) Math.max((long)Integer.MAX_VALUE, qty));
buffer.position(buffer.position() + byteCnt);
skipped += byteCnt;
qty -= byteCnt;
if (buffer.remaining() == 0) {
queue.poll();
try {
inputHandler.acknowledge(entry);
} catch (IOException e) {
// no operation!
} finally {
entry.free();
}
}
}
return skipped;
}
}
/** {@inheritDoc} */
public void close() throws IOException {
synchronized (this) {
if (! eof) {
clearQueue();
eof = true;
notifyAll();
inputHandler.close();
}
}
}
private void checkFailure() throws IOException {
assert Thread.holdsLock(this);
final IOException failure = this.failure;
if (failure != null) {
failure.fillInStackTrace();
try {
throw failure;
} finally {
eof = true;
clearQueue();
notifyAll();
this.failure = null;
}
}
}
/**
* A handler for events relating to the consumption of data from a {@link BufferPipeInputStream} instance.
*/
public interface InputHandler extends Closeable {
/**
* Acknowledges the successful processing of an input buffer. Though this method may throw an exception,
* it is not acted upon. The acknowledged resource is passed in, with its position set to the number of
* bytes consumed.
*
* @param pooled the pooled resource which was consumed
* @throws IOException if an I/O error occurs sending the acknowledgement
*/
void acknowledge(Pooled pooled) throws IOException;
/**
* Signifies that the user of the enclosing {@link BufferPipeInputStream} has called the {@code close()} method
* explicitly. Any thrown exception is propagated up to the caller of {@link BufferPipeInputStream#close() NioByteInput.close()}.
*
* @throws IOException if an I/O error occurs
*/
void close() throws IOException;
}
}
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