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/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD+Patents license found in the
* LICENSE file in the root directory of this source tree.
*/
// Copyright 2004-present Facebook. All Rights Reserved.
#pragma once
#include <condition_variable>
#include <future>
#include <deque>
#include <thread>
namespace faiss { namespace gpu {
class WorkerThread {
public:
WorkerThread();
/// Stops and waits for the worker thread to exit, flushing all
/// pending lambdas
~WorkerThread();
/// Request that the worker thread stop itself
void stop();
/// Blocking waits in the current thread for the worker thread to
/// stop
void waitForThreadExit();
/// Adds a lambda to run on the worker thread; returns a future that
/// can be used to block on its completion.
/// Future status is `true` if the lambda was run in the worker
/// thread; `false` if it was not run, because the worker thread is
/// exiting or has exited.
std::future<bool> add(std::function<void()> f);
private:
void startThread();
void threadMain();
void threadLoop();
/// Thread that all queued lambdas are run on
std::thread thread_;
/// Mutex for the queue and exit status
std::mutex mutex_;
/// Monitor for the exit status and the queue
std::condition_variable monitor_;
/// Whether or not we want the thread to exit
bool wantStop_;
/// Queue of pending lambdas to call
std::deque<std::pair<std::function<void()>, std::promise<bool>>> queue_;
};
} } // namespace