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

   1
   2 /*]  Copyright (c) 2009-2011, Charles McGarvey  [*****************************
   3 **]  All rights reserved.
   4 *
   5 * Distributable under the terms and conditions of the 2-clause BSD license;
   6 * see the file COPYING for a complete text of the license.
   7 *
   8 *****************************************************************************/
   9
  10 #ifndef _MOOF_MANAGER_HH_
  11 #define _MOOF_MANAGER_HH_
  12
  13 #include <string>
  14 #include <boost/shared_ptr.hpp>
  15
  16 #include <moof/hash.hh>
  17
  18
  19 /**
  20  * \file manager.hh
  21  * A manager is a collection of named objects of the same type.  Libraries
  22  * use reference counting to automagically delete objects which no longer
  23  * have any interested code.
  24  */
  25
  26 namespace moof {
  27
  28
  29 template <class T>
  30 class manager
  31 {
  32 public:
  33
  34         manager() :
  35                 retain_count_(1) {}
  36
  37         const std::string& name() const
  38         {
  39                 return name_;
  40         }
  41
  42         static boost::shared_ptr<T> instance(const std::string& name)
  43         {
  44                 return boost::shared_ptr<T>(retain(name), &release);
  45         }
  46
  47 private:
  48
  49         typedef stlplus::hash<std::string,T*,hash_function> ptr_lookup;
  50
  51         static T* retain(const std::string& name)
  52         {
  53                 typename ptr_lookup::iterator it = ptr_lookup_.find(name);
  54
  55                 if (it != ptr_lookup_.end())
  56                 {
  57                         ++((*it).second->retain_count_);
  58                         return (*it).second;
  59                 }
  60                 else
  61                 {
  62                         T* new_object(new T);
  63                         if (new_object)
  64                         {
  65                                 new_object->name_ = name;
  66                                 new_object->init(name);
  67                                 ptr_lookup_.insert(std::make_pair(name,
  68                                                         new_object));
  69                         }
  70                         return new_object;
  71                 }
  72         }
  73
  74         static void release(T* obj)
  75         {
  76                 if (--(obj->retain_count_) == 0)
  77                 {
  78                         ptr_lookup_.erase(obj->name_);
  79                         delete obj;
  80                 }
  81         }
  82
  83
  84         static ptr_lookup       ptr_lookup_;
  85         std::string             name_;
  86         unsigned                retain_count_;
  87 };
  88
  89 template <class T>
  90 hash<std::string,T*,hash_function> manager<T>::ptr_lookup_;
  91
  92
  93 } // namespace moof
  94
  95 #endif // _MOOF_MANAGER_HH_
  96