Line data    Source code

       1             : /**********************************************************************
       2             :  * $Id$
       3             :  *
       4             :  * Name:     cpl_auto_close.h
       5             :  * Project:  CPL - Common Portability Library
       6             :  * Purpose:  CPL Auto Close handling
       7             :  * Author:   Liu Yimin, ymwh@foxmail.com
       8             :  *
       9             :  **********************************************************************
      10             :  * Copyright (c) 2018, Liu Yimin
      11             :  *
      12             :  * Permission is hereby granted, free of charge, to any person obtaining a
      13             :  * copy of this software and associated documentation files (the "Software"),
      14             :  * to deal in the Software without restriction, including without limitation
      15             :  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      16             :  * and/or sell copies of the Software, and to permit persons to whom the
      17             :  * Software is furnished to do so, subject to the following conditions:
      18             :  *
      19             :  * The above copyright notice and this permission notice shall be included
      20             :  * in all copies or substantial portions of the Software.
      21             :  *
      22             :  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
      23             :  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
      24             :  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
      25             :  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
      26             :  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
      27             :  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
      28             :  * DEALINGS IN THE SOFTWARE.
      29             :  ****************************************************************************/
      30             : 
      31             : #ifndef CPL_AUTO_CLOSE_H_INCLUDED
      32             : #define CPL_AUTO_CLOSE_H_INCLUDED
      33             : 
      34             : #if defined(__cplusplus)
      35             : #include <type_traits>
      36             : 
      37             : /************************************************************************/
      38             : /*                           CPLAutoClose                               */
      39             : /************************************************************************/
      40             : 
      41             : /**
      42             :  * The class use the destructor to automatically close the resource.
      43             :  * Example:
      44             :  *     GDALDatasetH hDset = GDALOpen(path,GA_ReadOnly);
      45             :  *     CPLAutoClose<GDALDatasetH,void(*)(void*)>
      46             :  * autoclosehDset(hDset,GDALClose); Or: GDALDatasetH hDset =
      47             :  * GDALOpen(path,GA_ReadOnly); CPL_AUTO_CLOSE_WARP(hDset,GDALClose);
      48             :  */
      49             : template <typename _Ty, typename _Dx> class CPLAutoClose
      50             : {
      51             :     static_assert(!std::is_const<_Ty>::value && std::is_pointer<_Ty>::value,
      52             :                   "_Ty must is pointer type,_Dx must is function type");
      53             : 
      54             :   private:
      55             :     _Ty &m_ResourcePtr;
      56             :     _Dx m_CloseFunc;
      57             : 
      58             :   private:
      59             :     CPLAutoClose(const CPLAutoClose &) = delete;
      60             :     void operator=(const CPLAutoClose &) = delete;
      61             : 
      62             :   public:
      63             :     /**
      64             :      * @brief Constructor.
      65             :      * @param ptr Pointer to the resource object.
      66             :      * @param dt  Resource release(close) function.
      67             :      */
      68           2 :     explicit CPLAutoClose(_Ty &ptr, _Dx dt)
      69           2 :         : m_ResourcePtr(ptr), m_CloseFunc(dt)
      70             :     {
      71           2 :     }
      72             : 
      73             :     /**
      74             :      * @brief Destructor.
      75             :      */
      76           2 :     ~CPLAutoClose()
      77             :     {
      78           2 :         if (m_ResourcePtr && m_CloseFunc)
      79           2 :             m_CloseFunc(m_ResourcePtr);
      80           2 :     }
      81             : };
      82             : 
      83             : #define CPL_AUTO_CLOSE_WARP(hObject, closeFunc)                                \
      84             :     CPLAutoClose<decltype(hObject), decltype(closeFunc) *>                     \
      85             :         tAutoClose##hObject(hObject, closeFunc)
      86             : 
      87             : #endif /* __cplusplus */
      88             : 
      89             : #endif /* CPL_AUTO_CLOSE_H_INCLUDED */