EventLoop.h

/*
 * Copyright (C) 2006-2013 Marc Boris Duerner
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * As a special exception, you may use this file as part of a free
 * software library without restriction. Specifically, if other files
 * instantiate templates or use macros or inline functions from this
 * file, or you compile this file and link it with other files to
 * produce an executable, this file does not by itself cause the
 * resulting executable to be covered by the GNU General Public
 * License. This exception does not however invalidate any other
 * reasons why the executable file might be covered by the GNU Library
 * General Public License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
 
#ifndef PT_SYSTEM_EVENTLOOP_H
#define PT_SYSTEM_EVENTLOOP_H
 
#include <Pt/Event.h>
#include <Pt/Signal.h>
#include <Pt/Timespan.h>
#include <Pt/Allocator.h>
#include <Pt/Connectable.h>
#include <Pt/System/Api.h>
#include <Pt/System/Mutex.h>
#include <Pt/System/Timer.h>
#include <Pt/System/EventSink.h>
#include <map>
#include <deque>
 
#if __cplusplus >= 202002L
#include <Pt/Coroutine.h>
#include <Pt/System/Selectable.h>
#endif
 
namespace Pt {
 
namespace System {
 
class Timer;
class Selectable;
class Selector;
 
#if __cplusplus >= 202002L
class AsyncYield;
#endif

class PT_SYSTEM_API EventLoop : public Connectable
                              , public EventSink
{
    friend class Selectable;
    friend class Timer;
 
    public:
        static const std::size_t WaitInfinite = static_cast<const std::size_t>(-1);

        static const std::size_t WaitMax = WaitInfinite - 1;

        virtual ~EventLoop();

        void run();

        void exit();

        void processEvents();

        Signal<const Event&>& eventReceived()
        { return _event; }

        Signal<>& exited()
        { return _exited; }
 
#if __cplusplus >= 202002L
        AsyncYield yieldAsync();
#endif

        void post(Selectable& s)
        {
            onReady(s);
            wake();
        }

        void setReady(Selectable& s)
        {
            onReady(s);
        }

        virtual Selector& selector() = 0;
 
    protected:
        EventLoop();

        virtual void onRun() = 0;

        virtual void onExit() = 0;

        virtual void onCommitEvent(const Event& ev) = 0;

        virtual void onQueueEvent(const Event& ev) = 0;

        virtual void onWake() = 0;

        virtual void onProcessEvents() = 0;

        virtual void onAttachTimer(Timer& timer) = 0;

        virtual void onDetachTimer(Timer& timer) = 0;

        virtual void onAttachSelectable(Selectable&) = 0;

        virtual void onDetachSelectable(Selectable&) = 0;

        virtual void onReady(Selectable&) = 0;

        virtual void onCancel(Selectable&) = 0;
 
    private:
        Signal<> _exited;
        Signal<const Event&> _event;
};

class PT_SYSTEM_API EventQueue
{
    public:
        EventQueue();
 
        EventQueue(Allocator& a);
 
        virtual ~EventQueue();
 
        Allocator& allocator()
        { return *_usedalloc; }
 
        void exit();
 
        void pushEvent(const Event& event);
 
        bool processEvents(Signal<const Event&>& eventSignal);
 
    private:
        Mutex _mutex;
        Allocator _allocator;
        Allocator* _usedalloc;
        std::deque<Event*> _eventQueue;
        bool _exited;
};

class PT_SYSTEM_API TimerQueue
{
    typedef std::multimap<Timespan, Timer*> TimerMap;
 
    public:
        TimerQueue();
 
        virtual ~TimerQueue();
 
        void addTimer(Timer& timer);
 
        void removeTimer(Timer& timer);
 
        std::size_t processTimers();
 
    private:
        TimerMap _timers;
};
 
#if __cplusplus >= 202002L

class PT_SYSTEM_API AsyncYield : public Pt::Awaiter
                               , private Pt::System::Selectable
{
    public:
        explicit AsyncYield(EventLoop& loop)
        {
            this->setActive(loop);
        }
 
        virtual ~AsyncYield()
        {
            Selectable::cancel();
        }
 
        void await_resume() noexcept
        {}
 
    protected:
        void onBegin() override
        {
            this->post();
        }
 
        void cancel() override
        {
            Selectable::cancel();
        }
 
        void onCancel() override
        {
            _handle = nullptr;
        }
 
        void onAttach(Pt::System::EventLoop&) override
        {}
 
        void onDetach(Pt::System::EventLoop&) override
        {}
 
        bool onRun() override
        {
            this->setReady();
            return true;
        }
};
 
inline AsyncYield EventLoop::yieldAsync()
{
    return AsyncYield(*this);
}
 
#endif // __cplusplus >= 202002L
 
} // namespace System
 
} // namespace Pt
 
#endif // PT_SYSTEM_EVENTLOOP_H