src/PageState.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_PAGE_STATE_HPP
  25 #define XCSOAR_PAGE_STATE_HPP
  26
  27 #include "PageSettings.hpp"
  28
  29 #include <type_traits>
  30
  31 /**
  32  * Keeps track of the state of the "pages" subsystem.
  33  */
  34 struct PagesState {
  35   /**
  36    * The index of the current page in the list of configured pages,
  37    * see #PageSettings.
  38    *
  39    * This setting is only active if #special_page is not defined.
  40    * Otherwise, it is the page that we will return to after the user
  41    * decides to leave the #special_page.
  42    */
  43   unsigned current_index;
  44
  45   /**
  46    * If this attribute is defined (see PageLayout::IsDefined()), then
  47    * the current page is not the one in #PageSettings, specified by
  48    * #page_index, but a page that was created automatically.  For
  49    * example, it could be a page that was created by clicking on the
  50    * FLARM radar.  Pressing left/right will return to the last
  51    * configured page.
  52    */
  53   PageLayout special_page;
  54
  55   void Clear();
  56 };
  57
  58 static_assert(std::is_trivial<PagesState>::value, "type is not trivial");
  59
  60 #endif