OpenMesh
SingletonT.hh
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41 
42 
43 
44 
45 //=============================================================================
46 //
47 // Implements a simple singleton template
48 //
49 //=============================================================================
50 
51 
52 #ifndef __SINGLETON_HH__
53 #define __SINGLETON_HH__
54 
55 
56 //=== INCLUDES ================================================================
57 
58 // OpenMesh
59 #include <OpenMesh/Core/System/config.h>
60 
61 // STL
62 #include <stdexcept>
63 
64 
65 //== NAMESPACES ===============================================================
66 
67 
68 namespace OpenMesh {
69 
70 
71 //=== IMPLEMENTATION ==========================================================
72 
73 
78 template <typename T>
80 {
81 public:
82 
89  static T& Instance()
90  {
91  if (!pInstance__)
92  {
93  // check if singleton alive
94  if (destroyed__)
95  {
96  OnDeadReference();
97  }
98  // first time request -> initialize
99  else
100  {
101  Create();
102  }
103  }
104  return *pInstance__;
105  }
106 
107 
108 private:
109 
110  // Disable constructors/assignment to enforce uniqueness
111  SingletonT();
112  SingletonT(const SingletonT&);
113  SingletonT& operator=(const SingletonT&);
114 
115  // Create a new singleton and store its pointer
116  static void Create()
117  {
118  static T theInstance;
119  pInstance__ = &theInstance;
120  }
121 
122  // Will be called if instance is accessed after its lifetime has expired
123  static void OnDeadReference()
124  {
125  throw std::runtime_error("[Singelton error] - Dead reference detected!\n");
126  }
127 
128  virtual ~SingletonT()
129  {
130  pInstance__ = 0;
131  destroyed__ = true;
132  }
133 
134  static T* pInstance__;
135  static bool destroyed__;
136 };
137 
138 
139 
140 //=============================================================================
141 } // namespace OpenMesh
142 //=============================================================================
143 #if defined(OM_INCLUDE_TEMPLATES) && !defined(OPENMESH_SINGLETON_C)
144 # define OPENMESH_SINGLETON_TEMPLATES
145 # include "SingletonT_impl.hh"
146 #endif
147 //=============================================================================
148 #endif // __SINGLETON_HH__
149 //=============================================================================
A simple singleton template.
Definition: SingletonT.hh:79
Contains all the mesh ingredients like the polygonal mesh, the triangle mesh, different mesh kernels ...
Definition: MeshItems.hh:59
static T & Instance()
Singleton access function.
Definition: SingletonT.hh:89

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