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