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libdatachannel/src/processor.hpp

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2.5 KiB
C++

/**
* Copyright (c) 2020 Paul-Louis Ageneau
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef RTC_PROCESSOR_H
#define RTC_PROCESSOR_H
#include "include.hpp"
#include "init.hpp"
#include "threadpool.hpp"
#include <condition_variable>
#include <future>
#include <memory>
#include <mutex>
#include <queue>
namespace rtc {
// Processed tasks in order by delegating them to the thread pool
class Processor final {
public:
Processor() = default;
~Processor();
Processor(const Processor &) = delete;
Processor &operator=(const Processor &) = delete;
Processor(Processor &&) = delete;
Processor &operator=(Processor &&) = delete;
void join();
template <class F, class... Args>
auto enqueue(F &&f, Args &&... args) -> invoke_future_t<F, Args...>;
protected:
void schedule();
// Keep an init token
const init_token mInitToken = Init::Token();
std::queue<std::function<void()>> mTasks;
bool mPending = false; // true iff a task is pending in the thread pool
mutable std::mutex mMutex;
std::condition_variable mCondition;
};
template <class F, class... Args>
auto Processor::enqueue(F &&f, Args &&... args) -> invoke_future_t<F, Args...> {
std::unique_lock lock(mMutex);
using R = std::invoke_result_t<std::decay_t<F>, std::decay_t<Args>...>;
auto task = std::make_shared<std::packaged_task<R()>>(
std::bind(std::forward<F>(f), std::forward<Args>(args)...));
std::future<R> result = task->get_future();
auto bundle = [this, task = std::move(task)]() {
try {
(*task)();
} catch (const std::exception &e) {
PLOG_WARNING << "Unhandled exception in task: " << e.what();
}
schedule(); // chain the next task
};
if (!mPending) {
ThreadPool::Instance().enqueue(std::move(bundle));
mPending = true;
} else {
mTasks.emplace(std::move(bundle));
}
return result;
}
} // namespace rtc
#endif