Developer Documentation

SingletonT.hh
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40 * ========================================================================= */
41
42
43
44
45 //=============================================================================
46 //
47 // Implements a simple singleton template
48 //
49 //=============================================================================
50
51 #pragma once
52
53 //=== INCLUDES ================================================================
54
55 // OpenMesh
56 #include <OpenMesh/Core/System/config.h>
57
58 // STL
59 #include <stdexcept>
60
61
62 //== NAMESPACES ===============================================================
63
64
65 namespace OpenMesh {
66
67
68 //=== IMPLEMENTATION ==========================================================
69
70
75 template <typename T>
76 class SingletonT
77 {
78 public:
79
86 static T& Instance()
87 {
88 if (!pInstance__)
89 {
90 // check if singleton alive
91 if (destroyed__)
92 {
93 OnDeadReference();
94 }
95 // first time request -> initialize
96 else
97 {
98 Create();
99 }
100 }
101 return *pInstance__;
102 }
103
104
105 private:
106
107 // Disable constructors/assignment to enforce uniqueness
108 SingletonT();
109 SingletonT(const SingletonT&);
110 SingletonT& operator=(const SingletonT&);
111
112 // Create a new singleton and store its pointer
113 static void Create()
114 {
115 static T theInstance;
116 pInstance__ = &theInstance;
117 }
118
119 // Will be called if instance is accessed after its lifetime has expired
120 static void OnDeadReference()
121 {
122 throw std::runtime_error("[Singelton error] - Dead reference detected!\n");
123 }
124
125 virtual ~SingletonT()
126 {
127 pInstance__ = 0;
128 destroyed__ = true;
129 }
130
131 static T* pInstance__;
132 static bool destroyed__;
133 };
134
135
136
137 //=============================================================================
138 } // namespace OpenMesh
139 //=============================================================================
140 #if defined(OM_INCLUDE_TEMPLATES) && !defined(OPENMESH_SINGLETON_C)
141 # define OPENMESH_SINGLETON_TEMPLATES
142 # include "SingletonT_impl.hh"
143 #endif
144 //=============================================================================
config.h
OpenMesh::SingletonT
Definition: SingletonT.hh:76
OpenMesh
Definition: MeshItems.hh:59
OpenMesh::SingletonT::Instance
static T & Instance()
Definition: SingletonT.hh:86