tech.ydb.shaded.grpc.internal.SerializeReentrantCallsDirectExecutor Maven / Gradle / Ivy
/*
* Copyright 2015 The gRPC 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 io.grpc.internal;
import com.google.common.base.Preconditions;
import java.util.ArrayDeque;
import java.util.concurrent.Executor;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Executes a task directly in the calling thread, unless it's a reentrant call in which case the
* task is enqueued and executed once the calling task completes.
*
* The {@code Executor} assumes that reentrant calls are rare and its fast path is thus
* optimized for that - avoiding queuing and additional object creation altogether.
*
*
This class is not thread-safe.
*/
class SerializeReentrantCallsDirectExecutor implements Executor {
private static final Logger log =
Logger.getLogger(SerializeReentrantCallsDirectExecutor.class.getName());
private boolean executing;
// Lazily initialized if a reentrant call is detected.
private ArrayDeque taskQueue;
@Override
public void execute(Runnable task) {
Preconditions.checkNotNull(task, "'task' must not be null.");
if (!executing) {
executing = true;
try {
task.run();
} catch (Throwable t) {
log.log(Level.SEVERE, "Exception while executing runnable " + task, t);
} finally {
if (taskQueue != null) {
completeQueuedTasks();
}
executing = false;
}
} else {
enqueue(task);
}
}
private void completeQueuedTasks() {
Runnable task = null;
while ((task = taskQueue.poll()) != null) {
try {
task.run();
} catch (Throwable t) {
// Log it and keep going
log.log(Level.SEVERE, "Exception while executing runnable " + task, t);
}
}
}
private void enqueue(Runnable r) {
if (taskQueue == null) {
taskQueue = new ArrayDeque<>(4);
}
taskQueue.add(r);
}
}