ladybird/Libraries/LibCore/CEventLoop.h
Andreas Kling 17ee548bcd CEventLoop: Add wake(), a mechanism for waking up when blocked in select().
This patch generalizes the concept used in Piano to wake up the event loop
so it can react to something happening on a secondary thread.
Basically, there's a pipe who is always part of the file descriptor set we
pass to select(), and calling wake() simply writes a little to that pipe.
2019-07-14 10:20:57 +02:00

93 lines
2.2 KiB
C++

#pragma once
#include <AK/Badge.h>
#include <AK/HashMap.h>
#include <AK/OwnPtr.h>
#include <AK/Vector.h>
#include <AK/WeakPtr.h>
#include <LibCore/CLock.h>
#include <LibCore/CEvent.h>
#include <sys/select.h>
#include <sys/time.h>
#include <time.h>
class CObject;
class CNotifier;
class CEventLoop {
public:
CEventLoop();
virtual ~CEventLoop();
int exec();
enum class WaitMode {
WaitForEvents,
PollForEvents,
};
// processe events, generally called by exec() in a loop.
// this should really only be used for integrating with other event loops
void pump(WaitMode = WaitMode::WaitForEvents);
void post_event(CObject& receiver, OwnPtr<CEvent>&&);
static CEventLoop& main();
static CEventLoop& current();
bool was_exit_requested() const { return m_exit_requested; }
static int register_timer(CObject&, int milliseconds, bool should_reload);
static bool unregister_timer(int timer_id);
static void register_notifier(Badge<CNotifier>, CNotifier&);
static void unregister_notifier(Badge<CNotifier>, CNotifier&);
void quit(int);
virtual void take_pending_events_from(CEventLoop& other)
{
m_queued_events.append(move(other.m_queued_events));
}
static void wake();
protected:
virtual void add_file_descriptors_for_select(fd_set&, int& max_fd) { UNUSED_PARAM(max_fd); }
virtual void process_file_descriptors_after_select(const fd_set&) {}
virtual void do_processing() {}
private:
void wait_for_event(WaitMode);
void get_next_timer_expiration(timeval&);
struct QueuedEvent {
WeakPtr<CObject> receiver;
OwnPtr<CEvent> event;
};
Vector<QueuedEvent, 64> m_queued_events;
bool m_exit_requested { false };
int m_exit_code { 0 };
static int s_wake_pipe_fds[2];
CLock m_lock;
struct EventLoopTimer {
int timer_id { 0 };
int interval { 0 };
timeval fire_time;
bool should_reload { false };
WeakPtr<CObject> owner;
void reload(const timeval& now);
bool has_expired(const timeval& now) const;
};
static HashMap<int, OwnPtr<EventLoopTimer>>* s_timers;
static int s_next_timer_id;
static HashTable<CNotifier*>* s_notifiers;
};