wegen/FrOSCon26/examples/demo-uring.cpp

/*
  demo-uring.cpp  -  async file IO with io_uring

   Copyright (C)
     2026,            Hermann Vosseler <Ichthyostega@web.de>

  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU GPL version 2+ See the LICENSE file for details.

* ************************************************************************/


#include "commons.hpp"
#include "egl-display.hpp"
#include "gtk-uring-app.hpp"

#include <iostream>
#include <memory>
#include <thread>

using std::unique_ptr;

//-----------------hard-coded-config--
const size_t RING_SIZ = 5;

const uint VIDEO_WIDTH  = 320;
const uint VIDEO_HEIGHT = 240;
//-----------------hard-coded-config--


class UringVideoPlayer
  {
    using VideoDisplay = EglDisplay<uint8_t, VIDEO_WIDTH,VIDEO_HEIGHT>;
    using Buffer = VideoDisplay::Buffer;

    Glib::Dispatcher dispatchFrame_;
    VideoDisplay  videoDisplayer_;
    std::thread proactorThread_;

  public:
    UringVideoPlayer (Gtk::Window& appWindow)
      : videoDisplayer_{appWindow, dispatchFrame_, [this]{ return retrieveCurrFrame(); }}
      , proactorThread_{[this]{ playVideo(); }}
      { }

    void terminate();

  private:
    void
    playVideo()
      {
        // allocate buffer data structure
        // initialise URing
        // ++ proactor-loop ++
      }

    Buffer*
    retrieveCurrFrame()
      {
        ///////OOO threadsafe hand-over of current frame data
      }
  };


unique_ptr<UringVideoPlayer>
launchPlayer (Gtk::Window& appWindow)
{
  appWindow.resize (VIDEO_WIDTH, VIDEO_HEIGHT);

  auto player = std::make_unique<UringVideoPlayer> (appWindow);

  return player;
}



void
UringVideoPlayer::terminate()
{
  ///// signal stop to proactor
  videoDisplayer_.cleanUp();
}



int
main (int, const char*[])
{
    return GtkUringApp<UringVideoPlayer>{"io-uring-demo"}
            .onClick (launchPlayer)
            .onClose ([](auto& player){ player.terminate();})
            .run();
}