io.undertow.channels.GatedStreamSourceChannel Maven / Gradle / Ivy
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* JBoss, Home of Professional Open Source.
* Copyright 2014 Red Hat, Inc., and individual contributors
* as indicated by the @author tags.
*
* Licensed 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.undertow.channels;
import org.xnio.ChannelListener;
import org.xnio.ChannelListeners;
import org.xnio.Option;
import org.xnio.XnioExecutor;
import org.xnio.XnioIoThread;
import org.xnio.XnioWorker;
import org.xnio.channels.StreamSinkChannel;
import org.xnio.channels.StreamSourceChannel;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.concurrent.TimeUnit;
import static org.xnio.Bits.allAreClear;
import static org.xnio.Bits.allAreSet;
import static org.xnio.Bits.anyAreClear;
import static org.xnio.Bits.anyAreSet;
/**
* A 'gated' stream source channel.
*
* This channel has a gate which starts of closed. When the gate is closed reads will return 0. When the gate is opened
* reads will resume as normal.
*
* @author David M. Lloyd
*/
public final class GatedStreamSourceChannel implements StreamSourceChannel {
private final StreamSourceChannel delegate;
private final ChannelListener.SimpleSetter readSetter = new ChannelListener.SimpleSetter<>();
private final ChannelListener.SimpleSetter closeSetter = new ChannelListener.SimpleSetter<>();
/**
* Construct a new instance.
*
* @param delegate the channel to wrap
*/
public GatedStreamSourceChannel(final StreamSourceChannel delegate) {
this.delegate = delegate;
}
@SuppressWarnings("unused")
private int state;
private static final int FLAG_GATE_OPEN = 1 << 0;
private static final int FLAG_READS_RESUMED = 1 << 1;
private static final int FLAG_CLOSE_REQUESTED = 1 << 2;
private static final int FLAG_CLOSED = 1 << 3;
/**
* Open the gate and allow data to flow. Once opened, the gate cannot be closed other than closing the channel.
*
* If the shutdownReads() or close() method has already been called this will result it in being invoked on the
* delegate.
*/
public void openGate() throws IOException {
int val = state;
if (allAreSet(val, FLAG_GATE_OPEN)) {
return;
}
state |= FLAG_GATE_OPEN;
if (allAreSet(val, FLAG_CLOSED)) {
delegate.close();
} else {
if (allAreSet(val, FLAG_CLOSE_REQUESTED)) {
delegate.shutdownReads();
}
if (allAreSet(val, FLAG_READS_RESUMED)) {
delegate.wakeupReads();
}
}
}
public boolean isGateOpen() {
return allAreSet(state, FLAG_GATE_OPEN);
}
public XnioWorker getWorker() {
return delegate.getWorker();
}
@Override
public XnioIoThread getIoThread() {
return delegate.getIoThread();
}
@Override
public long transferTo(long position, long count, FileChannel target) throws IOException {
int val = state;
if (anyAreSet(val, FLAG_CLOSE_REQUESTED)) {
return -1;
}
if (anyAreClear(val, FLAG_GATE_OPEN)) {
return 0;
}
return delegate.transferTo(position, count, target);
}
@Override
public long transferTo(long count, ByteBuffer throughBuffer, StreamSinkChannel target) throws IOException {
int val = state;
if (anyAreSet(val, FLAG_CLOSE_REQUESTED)) {
return -1;
}
if (anyAreClear(val, FLAG_GATE_OPEN)) {
return 0;
}
return delegate.transferTo(count, throughBuffer, target);
}
@Override
public long read(ByteBuffer[] dsts, int offset, int length) throws IOException {
int val = state;
if (anyAreSet(val, FLAG_CLOSE_REQUESTED)) {
return -1;
}
if (anyAreClear(val, FLAG_GATE_OPEN)) {
return 0;
}
return delegate.read(dsts, offset, length);
}
@Override
public long read(ByteBuffer[] dsts) throws IOException {
int val = state;
if (anyAreSet(val, FLAG_CLOSE_REQUESTED)) {
return -1;
}
if (anyAreClear(val, FLAG_GATE_OPEN)) {
return 0;
}
return delegate.read(dsts);
}
@Override
public int read(ByteBuffer dst) throws IOException {
int val = state;
if (anyAreSet(val, FLAG_CLOSE_REQUESTED)) {
return -1;
}
if (anyAreClear(val, FLAG_GATE_OPEN)) {
return 0;
}
return delegate.read(dst);
}
@Override
public void suspendReads() {
if (anyAreSet(state, FLAG_GATE_OPEN)) {
delegate.suspendReads();
} else {
state &= ~FLAG_READS_RESUMED;
}
}
@Override
public void resumeReads() {
if (anyAreSet(state, FLAG_GATE_OPEN)) {
delegate.resumeReads();
} else {
state |= FLAG_READS_RESUMED;
}
}
@Override
public boolean isReadResumed() {
if (anyAreSet(state, FLAG_GATE_OPEN)) {
return delegate.isReadResumed();
} else {
return anyAreSet(state, FLAG_READS_RESUMED);
}
}
@Override
public void wakeupReads() {
if (anyAreSet(state, FLAG_GATE_OPEN)) {
delegate.resumeReads();
} else {
state |= FLAG_READS_RESUMED;
getIoThread().execute(new Runnable() {
@Override
public void run() {
ChannelListeners.invokeChannelListener(GatedStreamSourceChannel.this, readSetter.get());
}
});
}
}
@Override
public void shutdownReads() throws IOException {
if (anyAreSet(state, FLAG_GATE_OPEN)) {
delegate.shutdownReads();
} else {
state |= FLAG_CLOSE_REQUESTED;
}
}
@Override
public void awaitReadable() throws IOException {
if (anyAreSet(state, FLAG_GATE_OPEN)) {
delegate.awaitReadable();
} else {
throw new IllegalStateException();
}
}
@Override
public void awaitReadable(long time, TimeUnit timeUnit) throws IOException {
if (anyAreSet(state, FLAG_GATE_OPEN)) {
delegate.awaitReadable(time, timeUnit);
} else {
throw new IllegalStateException();
}
}
@Override
public XnioExecutor getReadThread() {
return delegate.getIoThread();
}
@Override
public ChannelListener.Setter getReadSetter() {
return readSetter;
}
public ChannelListener.Setter getCloseSetter() {
return closeSetter;
}
public void close() throws IOException {
if (allAreSet(state, FLAG_CLOSED)) {
return;
}
state |= FLAG_CLOSED;
if (anyAreSet(state, FLAG_GATE_OPEN)) {
delegate.close();
}
}
public boolean isOpen() {
return allAreClear(state, FLAG_CLOSED);
}
public boolean supportsOption(final Option option) {
return false;
}
public T getOption(final Option option) throws IOException {
return null;
}
public T setOption(final Option option, final T value) throws IllegalArgumentException, IOException {
return null;
}
/**
* Get the underlying channel if the gate is open, else return this channel.
*
* @return the underlying channel, or this channel if the gate is not open
*/
public StreamSourceChannel getChannel() {
return allAreSet(state, FLAG_GATE_OPEN) ? delegate : this;
}
}