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// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <atomic>
#include <condition_variable>
#include <functional>
#include <mutex>
#include <string>
#include <thread>
#include <type_traits>
#include <vector>
#include <queue>
#include "common/polyfill_thread.h"
#include "common/thread.h"
#include "common/unique_function.h"
namespace Common {
template <class StateType = void>
class StatefulThreadWorker {
static constexpr bool with_state = !std::is_same_v<StateType, void>;
struct DummyCallable {
int operator()(std::size_t) const noexcept {
return 0;
}
};
using Task =
std::conditional_t<with_state, UniqueFunction<void, StateType*>, UniqueFunction<void>>;
using StateMaker =
std::conditional_t<with_state, std::function<StateType(std::size_t)>, DummyCallable>;
public:
explicit StatefulThreadWorker(std::size_t num_workers, std::string_view name,
StateMaker func = {})
: workers_queued{num_workers}, thread_name{name} {
const auto lambda = [this, func](std::stop_token stop_token, std::size_t index) {
Common::SetCurrentThreadName(thread_name.data());
{
[[maybe_unused]] std::conditional_t<with_state, StateType, int> state{func(index)};
while (!stop_token.stop_requested()) {
Task task;
{
std::unique_lock lock{queue_mutex};
if (requests.empty()) {
wait_condition.notify_all();
}
Common::CondvarWait(condition, lock, stop_token,
[this] { return !requests.empty(); });
if (stop_token.stop_requested()) {
break;
}
task = std::move(requests.front());
requests.pop();
}
if constexpr (with_state) {
task(&state);
} else {
task();
}
++work_done;
}
}
++workers_stopped;
wait_condition.notify_all();
};
threads.reserve(num_workers);
for (std::size_t i = 0; i < num_workers; ++i) {
threads.emplace_back(lambda, i);
}
}
StatefulThreadWorker& operator=(const StatefulThreadWorker&) = delete;
StatefulThreadWorker(const StatefulThreadWorker&) = delete;
StatefulThreadWorker& operator=(StatefulThreadWorker&&) = delete;
StatefulThreadWorker(StatefulThreadWorker&&) = delete;
void QueueWork(Task work) {
{
std::unique_lock lock{queue_mutex};
requests.emplace(std::move(work));
++work_scheduled;
}
condition.notify_one();
}
void WaitForRequests(std::stop_token stop_token = {}) {
std::stop_callback callback(stop_token, [this] {
for (auto& thread : threads) {
thread.request_stop();
}
});
std::unique_lock lock{queue_mutex};
wait_condition.wait(lock, [this] {
return workers_stopped >= workers_queued || work_done >= work_scheduled;
});
}
const std::size_t NumWorkers() const noexcept {
return threads.size();
}
private:
std::queue<Task> requests;
std::mutex queue_mutex;
std::condition_variable_any condition;
std::condition_variable wait_condition;
std::atomic<std::size_t> work_scheduled{};
std::atomic<std::size_t> work_done{};
std::atomic<std::size_t> workers_stopped{};
std::atomic<std::size_t> workers_queued{};
std::string_view thread_name;
std::vector<std::jthread> threads;
};
using ThreadWorker = StatefulThreadWorker<>;
} // namespace Common
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