Dogcows Code - chaz/yoink/blob - src/Moof/Library.hh

   1
   2 /*******************************************************************************
   3
   4  Copyright (c) 2009, Charles McGarvey
   5  All rights reserved.
   6
   7  Redistribution   and   use  in  source  and  binary  forms,  with  or  without
   8  modification, are permitted provided that the following conditions are met:
   9
  10    * Redistributions  of  source  code  must retain the above copyright notice,
  11      this list of conditions and the following disclaimer.
  12    * Redistributions  in binary form must reproduce the above copyright notice,
  13      this  list of conditions and the following disclaimer in the documentation
  14      and/or other materials provided with the distribution.
  15
  16  THIS  SOFTWARE  IS  PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  17  AND  ANY  EXPRESS  OR  IMPLIED  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  19  DISCLAIMED.  IN  NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  20  FOR  ANY  DIRECT,  INDIRECT,  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  DAMAGES  (INCLUDING,  BUT  NOT  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  22  SERVICES;  LOSS  OF  USE,  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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  24  OR  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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  27 *******************************************************************************/
  28
  29 #ifndef _MOOF_LIBRARY_HH_
  30 #define _MOOF_LIBRARY_HH_
  31
  32 /**
  33  * @file Library.hh
  34  * A library is a collection of named objects of the same type.  Libraries use
  35  * reference counting to automagically delete objects which no longer have any
  36  * interested code.
  37  */
  38
  39 #include <memory>
  40 #include <string>
  41
  42 #include <boost/shared_ptr.hpp>
  43
  44 #include <Moof/Hash.hh>
  45
  46
  47 namespace Mf {
  48
  49
  50 template <class T>
  51 class Library
  52 {
  53         typedef std::pair<unsigned,T*>                                                  PtrValue;
  54         typedef stlplus::hash<std::string,PtrValue,getHash>             PtrMap;
  55
  56         static PtrMap   mPtrMap;
  57         std::string             mName;
  58
  59         static T* retain(const std::string& name)
  60         {
  61                 typename PtrMap::iterator it = mPtrMap.find(name);
  62
  63                 if (it != mPtrMap.end())
  64                 {
  65                         ++((*it).second.first);
  66                         return (*it).second.second;
  67                 }
  68                 else
  69                 {
  70                         T* newObj(new T(name));
  71                         if (newObj)
  72                         {
  73                                 mPtrMap.insert(std::make_pair(name, std::make_pair(1, newObj)));
  74                         }
  75                         return newObj;
  76                 }
  77         }
  78
  79         static void release(T* obj)
  80         {
  81                 releaseByName(obj->mName);
  82         }
  83
  84         static void releaseByName(const std::string& name)
  85         {
  86                 typename PtrMap::iterator it;
  87
  88                 if ((it = mPtrMap.find(name)) != mPtrMap.end() &&
  89                                 --(*it).second.first == 0)
  90                 {
  91                         delete (*it).second.second;
  92                         mPtrMap.erase((*it).first);
  93                 }
  94         }
  95
  96 public:
  97
  98         explicit Library(const std::string& name) :
  99                 mName(name) {}
 100
 101         const std::string& getName() const
 102         {
 103                 return mName;
 104         }
 105
 106         static boost::shared_ptr<T> getInstance(const std::string& name)
 107         {
 108                 return boost::shared_ptr<T>(retain(name), &release);
 109         }
 110 };
 111
 112 template <class T>
 113 stlplus::hash< std::string,std::pair<unsigned,T*>,getHash >
 114         Library<T>::mPtrMap;
 115
 116
 117 } // namespace Mf
 118
 119 #endif // _MOOF_LIBRARY_HH_
 120
 121 /** vim: set ts=4 sw=4 tw=80: *************************************************/
 122