100 lines
2.5 KiB
C++
100 lines
2.5 KiB
C++
/*
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* AsyncTaskThread.h
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef __ASYNC_TASK_THREAD_H__
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#define __ASYNC_TASK_THREAD_H__
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#include <thread>
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#include <memory>
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#include <mutex>
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#include "flow/network.h"
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#include "flow/ThreadHelper.actor.h"
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#include "flow/ThreadSafeQueue.h"
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class IAsyncTask {
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public:
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virtual void operator()() = 0;
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virtual ~IAsyncTask() = default;
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virtual bool isTerminate() const = 0;
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};
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template <class F>
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class AsyncTask final : public IAsyncTask {
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F func;
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public:
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AsyncTask(const F& func) : func(func) {}
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void operator()() override { func(); }
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bool isTerminate() const override { return false; }
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};
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class AsyncTaskThread {
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ThreadSafeQueue<std::unique_ptr<IAsyncTask>> queue;
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std::condition_variable cv;
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std::mutex m;
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std::thread thread;
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static void run(AsyncTaskThread* self);
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template <class F>
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void addTask(const F& func) {
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bool wakeUp = false;
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{
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std::lock_guard<std::mutex> g(m);
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wakeUp = queue.push(std::make_unique<AsyncTask<F>>(func));
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}
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if (wakeUp) {
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cv.notify_one();
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}
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}
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static const double meanDelay;
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public:
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AsyncTaskThread();
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// Warning: This destructor can hang if a task hangs, so it is
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// up to the caller to prevent tasks from hanging indefinitely
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~AsyncTaskThread();
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template <class F>
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auto execAsync(const F& func, TaskPriority priority = TaskPriority::DefaultOnMainThread)
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-> Future<decltype(func())> {
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if (g_network->isSimulated()) {
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return map(delayJittered(meanDelay), [func](Void _) { return func(); });
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}
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Promise<decltype(func())> promise;
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addTask([promise, func, priority] {
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try {
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auto funcResult = func();
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onMainThreadVoid([promise, funcResult] { promise.send(funcResult); }, nullptr, priority);
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} catch (Error& e) {
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TraceEvent("ErrorExecutingAsyncTask").error(e);
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onMainThreadVoid([promise, e] { promise.sendError(e); }, nullptr, priority);
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}
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});
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return promise.getFuture();
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}
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};
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#endif
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