ladybird/Ladybird/EventLoopImplementationQt.h
Zaggy1024 78e1defbfe Ladybird: Allow posting events to the Qt event loop from other threads
Previously, a QTimer was used to start processing of our event queue in
the main Qt event loop. Unfortunately, QTimers are not thread-safe, and
disallow starting of a timer from a different thread than it was
created in.

Instead, use a dummy QObject to post a custom QEvent to the main loop
from whatever thread we like, and process our event queue when it is
received by our dummy object.
2023-08-04 13:49:36 -06:00

89 lines
2.7 KiB
C++

/*
* Copyright (c) 2022-2023, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Badge.h>
#include <AK/HashMap.h>
#include <AK/NonnullOwnPtr.h>
#include <AK/OwnPtr.h>
#include <LibCore/EventLoopImplementation.h>
#include <QEvent>
#include <QEventLoop>
#include <QSocketNotifier>
#include <QTimer>
namespace Ladybird {
class EventLoopImplementationQtEventTarget;
class EventLoopManagerQt final : public Core::EventLoopManager {
public:
EventLoopManagerQt();
virtual ~EventLoopManagerQt() override;
virtual NonnullOwnPtr<Core::EventLoopImplementation> make_implementation() override;
virtual int register_timer(Core::Object&, int milliseconds, bool should_reload, Core::TimerShouldFireWhenNotVisible) override;
virtual bool unregister_timer(int timer_id) override;
virtual void register_notifier(Core::Notifier&) override;
virtual void unregister_notifier(Core::Notifier&) override;
virtual void did_post_event() override;
static bool event_target_received_event(Badge<EventLoopImplementationQtEventTarget>, QEvent* event);
// FIXME: These APIs only exist for obscure use-cases inside SerenityOS. Try to get rid of them.
virtual int register_signal(int, Function<void(int)>) override { return 0; }
virtual void unregister_signal(int) override { }
private:
NonnullOwnPtr<EventLoopImplementationQtEventTarget> m_main_thread_event_target;
};
class QtEventLoopManagerEvent final : public QEvent {
public:
static QEvent::Type process_event_queue_event_type()
{
static auto const type = static_cast<QEvent::Type>(QEvent::registerEventType());
return type;
}
QtEventLoopManagerEvent(QEvent::Type type)
: QEvent(type)
{
}
};
class EventLoopImplementationQt final : public Core::EventLoopImplementation {
public:
static NonnullOwnPtr<EventLoopImplementationQt> create() { return adopt_own(*new EventLoopImplementationQt); }
virtual ~EventLoopImplementationQt() override;
virtual int exec() override;
virtual size_t pump(PumpMode) override;
virtual void quit(int) override;
virtual void wake() override;
virtual void post_event(Core::Object& receiver, NonnullOwnPtr<Core::Event>&&) override;
// FIXME: These APIs only exist for obscure use-cases inside SerenityOS. Try to get rid of them.
virtual void unquit() override { }
virtual bool was_exit_requested() const override { return false; }
virtual void notify_forked_and_in_child() override { }
void set_main_loop() { m_main_loop = true; }
private:
friend class EventLoopManagerQt;
EventLoopImplementationQt();
bool is_main_loop() const { return m_main_loop; }
QEventLoop m_event_loop;
bool m_main_loop { false };
};
}