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

   1
   2 /*******************************************************************************
   3
   4  Copyright (c) 2009, Charles McGarvey
   5  All rights reserved.
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   7  Redistribution   and   use  in  source  and  binary  forms,  with  or  without
   8  modification, are permitted provided that the following conditions are met:
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  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.
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  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
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  27 *******************************************************************************/
  28
  29 #ifndef _MOOF_MIPPLETON_HH_
  30 #define _MOOF_MIPPLETON_HH_
  31
  32 /**
  33  * @file Mippleton.hh
  34  * Related to singletons, a mippleton is an object which can be obtained
  35  * globally using a unique name.  Unlike singletons, there can be multiple
  36  * mippletons per class, each with a different name or identifier.  Mippletons
  37  * are create automatically when they are first requested (retained) and deleted
  38  * after the last interested code releases its hold on the object.
  39  */
  40
  41 #include <string>
  42
  43 #include <boost/shared_ptr.hpp>
  44
  45 #include <Moof/Hash.hh>
  46
  47
  48 namespace Mf {
  49
  50
  51 template <class T>
  52 class Mippleton
  53 {
  54         typedef std::pair<unsigned,T*>                                                          PtrValue;
  55         typedef stlplus::hash<std::string,PtrValue,getHash>     PtrMap;
  56
  57         static PtrMap   ptrs_;
  58         std::string             name_;
  59
  60         inline static T* retain(const std::string& name)
  61         {
  62                 typename PtrMap::iterator it = ptrs_.find(name);
  63
  64                 if (it != ptrs_.end())
  65                 {
  66                         ++((*it).second.first);
  67                         return (*it).second.second;
  68                 }
  69                 else
  70                 {
  71                         T* newObj = new T(name);
  72                         ptrs_.insert(std::make_pair(name, std::make_pair(1, newObj)));
  73                         return newObj;
  74                 }
  75         }
  76
  77         inline static void release(T* obj)
  78         {
  79                 releaseByName(obj->name_);
  80         }
  81
  82         inline static void releaseByName(const std::string& name)
  83         {
  84                 typename PtrMap::iterator it;
  85
  86                 if ((it = ptrs_.find(name)) != ptrs_.end() && --(*it).second.first == 0)
  87                 {
  88                         delete (*it).second.second;
  89                         ptrs_.erase((*it).first);
  90                 }
  91         }
  92
  93 public:
  94         explicit Mippleton(const std::string& name) :
  95                 name_(name) {}
  96
  97         inline const std::string& getName() const
  98         {
  99                 return name_;
 100         }
 101
 102         inline static boost::shared_ptr<T> getInstance(const std::string& name)
 103         {
 104                 return boost::shared_ptr<T>(retain(name), &release);
 105         }
 106 };
 107
 108 template <class T>
 109 stlplus::hash< std::string,std::pair<unsigned,T*>,getHash >
 110         Mippleton<T>::ptrs_;
 111
 112
 113 } // namespace Mf
 114
 115 #endif // _MOOF_MIPPLETON_HH_
 116
 117 /** vim: set ts=4 sw=4 tw=80: *************************************************/
 118