Dogcows Code - chaz/yoink/blob - src/moof/manager.hh

   1
   2 /*]  Copyright (c) 2009-2010, Charles McGarvey  [**************************
   3 **]  All rights reserved.
   4 *
   5 * vi:ts=4 sw=4 tw=75
   6 *
   7 * Distributable under the terms and conditions of the 2-clause BSD license;
   8 * see the file COPYING for a complete text of the license.
   9 *
  10 **************************************************************************/
  11
  12 #ifndef _MOOF_MANAGER_HH_
  13 #define _MOOF_MANAGER_HH_
  14
  15 /**
  16  * \file manager.hh
  17  * A manager is a collection of named objects of the same type.  Libraries
  18  * use reference counting to automagically delete objects which no longer
  19  * have any interested code.
  20  */
  21
  22 #include <string>
  23
  24 #include <boost/shared_ptr.hpp>
  25
  26 #include <moof/hash.hh>
  27
  28
  29 namespace moof {
  30
  31
  32 template <class T>
  33 class manager
  34 {
  35 public:
  36
  37         manager() :
  38                 retain_count_(1) {}
  39
  40         const std::string& name() const
  41         {
  42                 return name_;
  43         }
  44
  45         static boost::shared_ptr<T> instance(const std::string& name)
  46         {
  47                 return boost::shared_ptr<T>(retain(name), &release);
  48         }
  49
  50
  51 private:
  52
  53         typedef stlplus::hash<std::string,T*,hash_function> ptr_lookup;
  54
  55         static T* retain(const std::string& name)
  56         {
  57                 typename ptr_lookup::iterator it = ptr_lookup_.find(name);
  58
  59                 if (it != ptr_lookup_.end())
  60                 {
  61                         ++((*it).second->retain_count_);
  62                         return (*it).second;
  63                 }
  64                 else
  65                 {
  66                         T* new_object(new T);
  67                         if (new_object)
  68                         {
  69                                 new_object->name_ = name;
  70                                 new_object->init(name);
  71                                 ptr_lookup_.insert(std::make_pair(name, new_object));
  72                         }
  73                         return new_object;
  74                 }
  75         }
  76
  77         static void release(T* obj)
  78         {
  79                 if (--(obj->retain_count_) == 0)
  80                 {
  81                         ptr_lookup_.erase(obj->name_);
  82                         delete obj;
  83                 }
  84         }
  85
  86
  87         static ptr_lookup       ptr_lookup_;
  88         std::string                     name_;
  89         unsigned                        retain_count_;
  90 };
  91
  92 template <class T>
  93 hash<std::string,T*,hash_function> manager<T>::ptr_lookup_;
  94
  95
  96 } // namespace moof
  97
  98 #endif // _MOOF_MANAGER_HH_
  99