1 files changed, 323 insertions, 0 deletions
diff --git a/src/common/polyfill_thread.h b/src/common/polyfill_thread.h
new file mode 100644
index 000000000..5a8d1ce08
--- /dev/null
+++ b/src/common/polyfill_thread.h
@@ -0,0 +1,323 @@
+// SPDX-FileCopyrightText: 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//
+// TODO: remove this file when jthread is supported by all compilation targets
+//
+
+#pragma once
+
+#include <version>
+
+#ifdef __cpp_lib_jthread
+
+#include <stop_token>
+#include <thread>
+
+namespace Common {
+
+template <typename Condvar, typename Lock, typename Pred>
+void CondvarWait(Condvar& cv, Lock& lock, std::stop_token token, Pred&& pred) {
+    cv.wait(lock, token, std::move(pred));
+}
+
+} // namespace Common
+
+#else
+
+#include <atomic>
+#include <functional>
+#include <list>
+#include <memory>
+#include <mutex>
+#include <optional>
+#include <thread>
+#include <type_traits>
+
+namespace std {
+namespace polyfill {
+
+using stop_state_callbacks = list<function<void()>>;
+
+class stop_state {
+public:
+    stop_state() = default;
+    ~stop_state() = default;
+
+    bool request_stop() {
+        stop_state_callbacks callbacks;
+
+        {
+            scoped_lock lk{m_lock};
+
+            if (m_stop_requested.load()) {
+                // Already set, nothing to do
+                return false;
+            }
+
+            // Set as requested
+            m_stop_requested = true;
+
+            // Copy callback list
+            callbacks = m_callbacks;
+        }
+
+        for (auto callback : callbacks) {
+            callback();
+        }
+
+        return true;
+    }
+
+    bool stop_requested() const {
+        return m_stop_requested.load();
+    }
+
+    stop_state_callbacks::const_iterator insert_callback(function<void()> f) {
+        stop_state_callbacks::const_iterator ret{};
+        bool should_run{};
+
+        {
+            scoped_lock lk{m_lock};
+            should_run = m_stop_requested.load();
+            m_callbacks.push_front(f);
+            ret = m_callbacks.begin();
+        }
+
+        if (should_run) {
+            f();
+        }
+
+        return ret;
+    }
+
+    void remove_callback(stop_state_callbacks::const_iterator it) {
+        scoped_lock lk{m_lock};
+        m_callbacks.erase(it);
+    }
+
+private:
+    mutex m_lock;
+    atomic<bool> m_stop_requested;
+    stop_state_callbacks m_callbacks;
+};
+
+} // namespace polyfill
+
+class stop_token;
+class stop_source;
+struct nostopstate_t {
+    explicit nostopstate_t() = default;
+};
+inline constexpr nostopstate_t nostopstate{};
+
+template <class Callback>
+class stop_callback;
+
+class stop_token {
+public:
+    stop_token() noexcept = default;
+
+    stop_token(const stop_token&) noexcept = default;
+    stop_token(stop_token&&) noexcept = default;
+    stop_token& operator=(const stop_token&) noexcept = default;
+    stop_token& operator=(stop_token&&) noexcept = default;
+    ~stop_token() = default;
+
+    void swap(stop_token& other) noexcept {
+        m_stop_state.swap(other.m_stop_state);
+    }
+
+    [[nodiscard]] bool stop_requested() const noexcept {
+        return m_stop_state && m_stop_state->stop_requested();
+    }
+    [[nodiscard]] bool stop_possible() const noexcept {
+        return m_stop_state != nullptr;
+    }
+
+private:
+    friend class stop_source;
+    template <typename Callback>
+    friend class stop_callback;
+    stop_token(shared_ptr<polyfill::stop_state> stop_state) : m_stop_state(move(stop_state)) {}
+
+private:
+    shared_ptr<polyfill::stop_state> m_stop_state;
+};
+
+class stop_source {
+public:
+    stop_source() : m_stop_state(make_shared<polyfill::stop_state>()) {}
+    explicit stop_source(nostopstate_t) noexcept {}
+
+    stop_source(const stop_source&) noexcept = default;
+    stop_source(stop_source&&) noexcept = default;
+    stop_source& operator=(const stop_source&) noexcept = default;
+    stop_source& operator=(stop_source&&) noexcept = default;
+    ~stop_source() = default;
+    void swap(stop_source& other) noexcept {
+        m_stop_state.swap(other.m_stop_state);
+    }
+
+    [[nodiscard]] stop_token get_token() const noexcept {
+        return stop_token(m_stop_state);
+    }
+    [[nodiscard]] bool stop_possible() const noexcept {
+        return m_stop_state != nullptr;
+    }
+    [[nodiscard]] bool stop_requested() const noexcept {
+        return m_stop_state && m_stop_state->stop_requested();
+    }
+    bool request_stop() noexcept {
+        return m_stop_state && m_stop_state->request_stop();
+    }
+
+private:
+    friend class jthread;
+    explicit stop_source(shared_ptr<polyfill::stop_state> stop_state)
+        : m_stop_state(move(stop_state)) {}
+
+private:
+    shared_ptr<polyfill::stop_state> m_stop_state;
+};
+
+template <typename Callback>
+class stop_callback {
+    static_assert(is_nothrow_destructible_v<Callback>);
+    static_assert(is_invocable_v<Callback>);
+
+public:
+    using callback_type = Callback;
+
+    template <typename C>
+    requires constructible_from<Callback, C>
+    explicit stop_callback(const stop_token& st,
+                           C&& cb) noexcept(is_nothrow_constructible_v<Callback, C>)
+        : m_stop_state(st.m_stop_state) {
+        if (m_stop_state) {
+            m_callback = m_stop_state->insert_callback(move(cb));
+        }
+    }
+    template <typename C>
+    requires constructible_from<Callback, C>
+    explicit stop_callback(stop_token&& st,
+                           C&& cb) noexcept(is_nothrow_constructible_v<Callback, C>)
+        : m_stop_state(move(st.m_stop_state)) {
+        if (m_stop_state) {
+            m_callback = m_stop_state->insert_callback(move(cb));
+        }
+    }
+    ~stop_callback() {
+        if (m_stop_state && m_callback) {
+            m_stop_state->remove_callback(*m_callback);
+        }
+    }
+
+    stop_callback(const stop_callback&) = delete;
+    stop_callback(stop_callback&&) = delete;
+    stop_callback& operator=(const stop_callback&) = delete;
+    stop_callback& operator=(stop_callback&&) = delete;
+
+private:
+    shared_ptr<polyfill::stop_state> m_stop_state;
+    optional<polyfill::stop_state_callbacks::const_iterator> m_callback;
+};
+
+template <typename Callback>
+stop_callback(stop_token, Callback) -> stop_callback<Callback>;
+
+class jthread {
+public:
+    using id = thread::id;
+    using native_handle_type = thread::native_handle_type;
+
+    jthread() noexcept = default;
+
+    template <typename F, typename... Args,
+              typename = enable_if_t<!is_same_v<remove_cvref_t<F>, jthread>>>
+    explicit jthread(F&& f, Args&&... args)
+        : m_stop_state(make_shared<polyfill::stop_state>()),
+          m_thread(make_thread(move(f), move(args)...)) {}
+
+    ~jthread() {
+        if (joinable()) {
+            request_stop();
+            join();
+        }
+    }
+
+    jthread(const jthread&) = delete;
+    jthread(jthread&&) noexcept = default;
+    jthread& operator=(const jthread&) = delete;
+
+    jthread& operator=(jthread&& other) noexcept {
+        m_thread.swap(other.m_thread);
+        m_stop_state.swap(other.m_stop_state);
+        return *this;
+    }
+
+    void swap(jthread& other) noexcept {
+        m_thread.swap(other.m_thread);
+        m_stop_state.swap(other.m_stop_state);
+    }
+    [[nodiscard]] bool joinable() const noexcept {
+        return m_thread.joinable();
+    }
+    void join() {
+        m_thread.join();
+    }
+    void detach() {
+        m_thread.detach();
+        m_stop_state.reset();
+    }
+
+    [[nodiscard]] id get_id() const noexcept {
+        return m_thread.get_id();
+    }
+    [[nodiscard]] native_handle_type native_handle() {
+        return m_thread.native_handle();
+    }
+    [[nodiscard]] stop_source get_stop_source() noexcept {
+        return stop_source(m_stop_state);
+    }
+    [[nodiscard]] stop_token get_stop_token() const noexcept {
+        return stop_source(m_stop_state).get_token();
+    }
+    bool request_stop() noexcept {
+        return get_stop_source().request_stop();
+    }
+    [[nodiscard]] static unsigned int hardware_concurrency() noexcept {
+        return thread::hardware_concurrency();
+    }
+
+private:
+    template <typename F, typename... Args>
+    thread make_thread(F&& f, Args&&... args) {
+        if constexpr (is_invocable_v<decay_t<F>, stop_token, decay_t<Args>...>) {
+            return thread(move(f), get_stop_token(), move(args)...);
+        } else {
+            return thread(move(f), move(args)...);
+        }
+    }
+
+    shared_ptr<polyfill::stop_state> m_stop_state;
+    thread m_thread;
+};
+
+} // namespace std
+
+namespace Common {
+
+template <typename Condvar, typename Lock, typename Pred>
+void CondvarWait(Condvar& cv, Lock& lock, std::stop_token token, Pred pred) {
+    if (token.stop_requested()) {
+        return;
+    }
+
+    std::stop_callback callback(token, [&] { cv.notify_all(); });
+    cv.wait(lock, [&] { return pred() || token.stop_requested(); });
+}
+
+} // namespace Common
+
+#endif