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// Copyright 2023 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 <cstddef>
#include <memory>
#include <mutex>
#include <new>
#include "common/polyfill_thread.h"
namespace Common {
namespace detail {
constexpr std::size_t DefaultCapacity = 0x1000;
} // namespace detail
template <typename T, std::size_t Capacity = detail::DefaultCapacity>
class SPSCQueue {
static_assert((Capacity & (Capacity - 1)) == 0, "Capacity must be a power of two.");
public:
template <typename... Args>
bool TryEmplace(Args&&... args) {
return Emplace<PushMode::Try>(std::forward<Args>(args)...);
}
template <typename... Args>
void EmplaceWait(Args&&... args) {
Emplace<PushMode::Wait>(std::forward<Args>(args)...);
}
bool TryPop(T& t) {
return Pop<PopMode::Try>(t);
}
void PopWait(T& t) {
Pop<PopMode::Wait>(t);
}
void PopWait(T& t, std::stop_token stop_token) {
Pop<PopMode::WaitWithStopToken>(t, stop_token);
}
T PopWait() {
T t;
Pop<PopMode::Wait>(t);
return t;
}
T PopWait(std::stop_token stop_token) {
T t;
Pop<PopMode::WaitWithStopToken>(t, stop_token);
return t;
}
private:
enum class PushMode {
Try,
Wait,
Count,
};
enum class PopMode {
Try,
Wait,
WaitWithStopToken,
Count,
};
template <PushMode Mode, typename... Args>
bool Emplace(Args&&... args) {
const std::size_t write_index = m_write_index.load(std::memory_order::relaxed);
if constexpr (Mode == PushMode::Try) {
// Check if we have free slots to write to.
if ((write_index - m_read_index.load(std::memory_order::acquire)) == Capacity) {
return false;
}
} else if constexpr (Mode == PushMode::Wait) {
// Wait until we have free slots to write to.
std::unique_lock lock{producer_cv_mutex};
producer_cv.wait(lock, [this, write_index] {
return (write_index - m_read_index.load(std::memory_order::acquire)) < Capacity;
});
} else {
static_assert(Mode < PushMode::Count, "Invalid PushMode.");
}
// Determine the position to write to.
const std::size_t pos = write_index % Capacity;
// Emplace into the queue.
new (std::addressof(m_data[pos])) T(std::forward<Args>(args)...);
// Increment the write index.
++m_write_index;
// Notify the consumer that we have pushed into the queue.
std::scoped_lock lock{consumer_cv_mutex};
consumer_cv.notify_one();
return true;
}
template <PopMode Mode>
bool Pop(T& t, [[maybe_unused]] std::stop_token stop_token = {}) {
const std::size_t read_index = m_read_index.load(std::memory_order::relaxed);
if constexpr (Mode == PopMode::Try) {
// Check if the queue is empty.
if (read_index == m_write_index.load(std::memory_order::acquire)) {
return false;
}
} else if constexpr (Mode == PopMode::Wait) {
// Wait until the queue is not empty.
std::unique_lock lock{consumer_cv_mutex};
consumer_cv.wait(lock, [this, read_index] {
return read_index != m_write_index.load(std::memory_order::acquire);
});
} else if constexpr (Mode == PopMode::WaitWithStopToken) {
// Wait until the queue is not empty.
std::unique_lock lock{consumer_cv_mutex};
Common::CondvarWait(consumer_cv, lock, stop_token, [this, read_index] {
return read_index != m_write_index.load(std::memory_order::acquire);
});
if (stop_token.stop_requested()) {
return false;
}
} else {
static_assert(Mode < PopMode::Count, "Invalid PopMode.");
}
// Determine the position to read from.
const std::size_t pos = read_index % Capacity;
// Pop the data off the queue, moving it.
t = std::move(m_data[pos]);
// Increment the read index.
++m_read_index;
// Notify the producer that we have popped off the queue.
std::scoped_lock lock{producer_cv_mutex};
producer_cv.notify_one();
return true;
}
alignas(128) std::atomic_size_t m_read_index{0};
alignas(128) std::atomic_size_t m_write_index{0};
std::array<T, Capacity> m_data;
std::condition_variable_any producer_cv;
std::mutex producer_cv_mutex;
std::condition_variable_any consumer_cv;
std::mutex consumer_cv_mutex;
};
template <typename T, std::size_t Capacity = detail::DefaultCapacity>
class MPSCQueue {
public:
template <typename... Args>
bool TryEmplace(Args&&... args) {
std::scoped_lock lock{write_mutex};
return spsc_queue.TryEmplace(std::forward<Args>(args)...);
}
template <typename... Args>
void EmplaceWait(Args&&... args) {
std::scoped_lock lock{write_mutex};
spsc_queue.EmplaceWait(std::forward<Args>(args)...);
}
bool TryPop(T& t) {
return spsc_queue.TryPop(t);
}
void PopWait(T& t) {
spsc_queue.PopWait(t);
}
void PopWait(T& t, std::stop_token stop_token) {
spsc_queue.PopWait(t, stop_token);
}
T PopWait() {
return spsc_queue.PopWait();
}
T PopWait(std::stop_token stop_token) {
return spsc_queue.PopWait(stop_token);
}
private:
SPSCQueue<T, Capacity> spsc_queue;
std::mutex write_mutex;
};
template <typename T, std::size_t Capacity = detail::DefaultCapacity>
class MPMCQueue {
public:
template <typename... Args>
bool TryEmplace(Args&&... args) {
std::scoped_lock lock{write_mutex};
return spsc_queue.TryEmplace(std::forward<Args>(args)...);
}
template <typename... Args>
void EmplaceWait(Args&&... args) {
std::scoped_lock lock{write_mutex};
spsc_queue.EmplaceWait(std::forward<Args>(args)...);
}
bool TryPop(T& t) {
std::scoped_lock lock{read_mutex};
return spsc_queue.TryPop(t);
}
void PopWait(T& t) {
std::scoped_lock lock{read_mutex};
spsc_queue.PopWait(t);
}
void PopWait(T& t, std::stop_token stop_token) {
std::scoped_lock lock{read_mutex};
spsc_queue.PopWait(t, stop_token);
}
T PopWait() {
std::scoped_lock lock{read_mutex};
return spsc_queue.PopWait();
}
T PopWait(std::stop_token stop_token) {
std::scoped_lock lock{read_mutex};
return spsc_queue.PopWait(stop_token);
}
private:
SPSCQueue<T, Capacity> spsc_queue;
std::mutex write_mutex;
std::mutex read_mutex;
};
} // namespace Common
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