77 lines
2.0 KiB
C++
77 lines
2.0 KiB
C++
// Copyright 2017 Dolphin Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#pragma once
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#include <QCoreApplication>
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#include <QEvent>
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#include <QPointer>
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#include <QThread>
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#include <optional>
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#include <type_traits>
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#include <utility>
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#include "Common/Event.h"
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#include "DolphinQt/QtUtils/QueueOnObject.h"
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class QObject;
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// QWidget and subclasses are not thread-safe! This helper takes arbitrary code from any thread,
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// safely runs it on the appropriate GUI thread, waits for it to finish, and returns the result.
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//
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// If the target object is destructed before the code gets to run, the QPointer will be nulled and
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// the function will return nullopt.
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template <typename F>
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auto RunOnObject(QObject* object, F&& functor)
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{
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using OptionalResultT = std::optional<std::invoke_result_t<F>>;
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// If we queue up a functor on the current thread, it won't run until we return to the event loop,
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// which means waiting for it to finish will never complete. Instead, run it immediately.
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if (object->thread() == QThread::currentThread())
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return OptionalResultT(functor());
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class FnInvokeEvent : public QEvent
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{
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public:
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FnInvokeEvent(F&& functor, QObject* obj, Common::Event& event, OptionalResultT& result)
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: QEvent(QEvent::None), m_func(std::move(functor)), m_obj(obj), m_event(event),
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m_result(result)
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{
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}
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~FnInvokeEvent()
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{
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if (m_obj)
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{
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m_result = m_func();
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}
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else
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{
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// is already nullopt
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}
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m_event.Set();
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}
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private:
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F m_func;
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QPointer<QObject> m_obj;
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Common::Event& m_event;
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OptionalResultT& m_result;
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};
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Common::Event event{};
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OptionalResultT result = std::nullopt;
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QCoreApplication::postEvent(object,
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new FnInvokeEvent(std::forward<F>(functor), object, event, result));
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event.Wait();
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return result;
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}
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template <typename Base, typename Type, typename Receiver>
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auto RunOnObject(Receiver* obj, Type Base::*func)
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{
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return RunOnObject(obj, [obj, func] { return (obj->*func)(); });
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}
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