/*
* Copyright 2013 the original author or authors.
*
* 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 org.gradle.cache.internal.locklistener;
import org.gradle.api.logging.Logger;
import org.gradle.api.logging.Logging;
import org.gradle.cache.internal.FileLockCommunicator;
import org.gradle.cache.internal.GracefullyStoppedException;
import org.gradle.internal.concurrent.ExecutorFactory;
import org.gradle.internal.concurrent.Stoppable;
import org.gradle.internal.concurrent.StoppableExecutor;
import org.gradle.internal.remote.internal.inet.InetAddressFactory;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
public class DefaultFileLockContentionHandler implements FileLockContentionHandler, Stoppable {
private static final Logger LOGGER = Logging.getLogger(DefaultFileLockContentionHandler.class);
private final Lock lock = new ReentrantLock();
private final Map<Long, Runnable> contendedActions = new HashMap<Long, Runnable>();
private final ExecutorFactory executorFactory;
private final InetAddressFactory addressFactory;
private FileLockCommunicator communicator;
private StoppableExecutor executor;
private boolean stopped;
public DefaultFileLockContentionHandler(ExecutorFactory executorFactory, InetAddressFactory addressFactory) {
this.executorFactory = executorFactory;
this.addressFactory = addressFactory;
}
private Runnable listener() {
return new Runnable() {
public void run() {
try {
LOGGER.debug("Starting file lock listener thread.");
doRun();
} catch (Throwable t) {
//Logging exception here is only needed because by default Gradle does not show the stack trace
LOGGER.error("Problems handling incoming cache access requests.", t);
} finally {
LOGGER.debug("File lock listener thread completed.");
}
}
private void doRun() {
while (true) {
long lockId;
try {
lockId = communicator.receive();
} catch (GracefullyStoppedException e) {
return;
}
lock.lock();
Runnable action;
try {
action = contendedActions.get(lockId);
if (action == null) {
//received access request for lock that is already closed
continue;
}
} finally {
lock.unlock();
}
action.run();
}
}
};
}
public void start(long lockId, Runnable whenContended) {
lock.lock();
try {
assertNotStopped();
if (communicator == null) {
throw new IllegalStateException("Must initialize the handler by reserving the port first.");
}
if (executor == null) {
executor = executorFactory.create("File lock request listener");
executor.execute(listener());
}
if (contendedActions.containsKey(lockId)) {
throw new UnsupportedOperationException("Multiple contention actions for a given lock are currently not supported.");
}
contendedActions.put(lockId, whenContended);
} finally {
lock.unlock();
}
}
public void pingOwner(int port, long lockId, String displayName) {
getCommunicator().pingOwner(port, lockId, displayName);
}
private void assertNotStopped() {
if (stopped) {
throw new IllegalStateException(
"Cannot start managing file contention because this handler has been closed.");
}
}
public void stop(long lockId) {
lock.lock();
try {
contendedActions.remove(lockId);
} finally {
lock.unlock();
}
}
public void stop() {
lock.lock();
try {
stopped = true;
contendedActions.clear();
if (communicator != null) {
communicator.stop();
}
} finally {
lock.unlock();
}
if (executor != null) {
executor.stop();
}
}
public int reservePort() {
return getCommunicator().getPort();
}
private FileLockCommunicator getCommunicator() {
lock.lock();
try {
assertNotStopped();
if (communicator == null) {
communicator = new FileLockCommunicator(addressFactory);
}
return communicator;
} finally {
lock.unlock();
}
}
}