singletons.hxx

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/****************************************************************************
 * NxWidgets/libnxwidgets/include/singletons.hxx
 *
 *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX, NxWidgets, nor the names of its contributors
 *    me be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************
 *
 * Portions of this package derive from Woopsi (http://woopsi.org/) and
 * portions are original efforts.  It is difficult to determine at this
 * point what parts are original efforts and which parts derive from Woopsi.
 * However, in any event, the work of  Antony Dzeryn will be acknowledged
 * in most NxWidget files.  Thanks Antony!
 *
 *   Copyright (c) 2007-2011, Antony Dzeryn
 *   All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the names "Woopsi", "Simian Zombie" nor the
 *   names of its contributors may be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Antony Dzeryn ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL Antony Dzeryn BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

#ifndef __INCLUDE_SINGLETONS_HXX
#define __INCLUDE_SINGLETONS_HXX

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <stdbool.h>

#include <cnxtimer.hxx>

/****************************************************************************
 * Pre-Processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Implementation Classes
 ****************************************************************************/

#if defined(__cplusplus)

namespace NXWidgets
{
  /**
   * Forward References
   */

  class CWidgetStyle;
  class CNxString;

  /**
   * Global singleton instances
   */

  extern CWidgetStyle        *g_defaultWidgetStyle; /**< The default widget style */
  extern CNxString           *g_nullString;         /**< The reusable empty string */
  extern TNxArray<CNxTimer*> *g_nxTimers;           /**< An array of all timers */

  /**
   * Setup misc singleton instances.
   *
   * Q: Why is there here?
   * A: Because it needs to be done one time before any widgets are created.
   * Q: So why isn't it just the default style just a statically constructed class?
   * A: Because not all platforms will support static class constructions.
   * Q: Why isn't it part of CNxServer?
   * A: Because the singletons may be needed before the server is started.
   */

  void instantiateSingletons(void);

  /**
   * Free the singleton instances when the last NX server is destroyed.
   *
   * Q: Why is there here is it is only called as part of the CNxServer destructor?
   * A: Just for symmetry with instantiateSingletons().
   */

  void freeSingletons(void);
}

#endif // __cplusplus

#endif // __INCLUDE_SINGLETONS_HXX