src/Event/Notify.hpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #ifndef XCSOAR_EVENT_NOTIFY_HPP
  25 #define XCSOAR_EVENT_NOTIFY_HPP
  26
  27 #include "Util/NonCopyable.hpp"
  28
  29 #ifdef USE_GDI
  30 #include "Screen/Window.hpp"
  31 #endif
  32
  33 #include <atomic>
  34
  35 /**
  36  * This class implements message passing from any thread to the main
  37  * thread.  To use it, subclass it and implement the abstract method
  38  * OnNotification().
  39  */
  40 class Notify : private
  41 #ifndef USE_GDI
  42                NonCopyable
  43 #else
  44                Window
  45 #endif
  46 {
  47   std::atomic<bool> pending;
  48
  49 #if defined(ANDROID) || defined(USE_EGL)
  50   friend class EventLoop;
  51 #elif defined(ENABLE_SDL)
  52   friend class EventLoop;
  53 #endif
  54
  55 public:
  56   Notify();
  57   ~Notify();
  58
  59   /**
  60    * Send a notification to this object.  This method can be called
  61    * from any thread.
  62    */
  63   void SendNotification();
  64
  65   /**
  66    * Clear any pending notification.
  67    */
  68   void ClearNotification();
  69
  70 private:
  71   void RunNotification();
  72
  73   /**
  74    * Called by the event loop when the "notify" message is received.
  75    */
  76   static void Callback(void *ctx);
  77
  78 protected:
  79   /**
  80    * Called after SendNotification() has been called at least once.
  81    * This method runs in the main thread.
  82    */
  83   virtual void OnNotification() = 0;
  84
  85 #ifdef USE_GDI
  86   virtual bool OnUser(unsigned id) override;
  87 #endif
  88 };
  89
  90 #endif