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singletonref.hxx
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19 
20 #ifndef INCLUDED_SALHELPER_SINGLETONREF_HXX
21 #define INCLUDED_SALHELPER_SINGLETONREF_HXX
22 
23 #include <sal/config.h>
24 
25 #include <cstddef>
26 
27 #include <osl/mutex.hxx>
28 #include <rtl/instance.hxx>
29 #include <osl/diagnose.h>
30 #include <osl/getglobalmutex.hxx>
31 
32 
33 namespace salhelper{
34 
35 
68 template< class SingletonClass >
70 {
71 
72  // member
73 
74  private:
75 
77  static SingletonClass* m_pInstance;
78 
80  static sal_Int32 m_nRef;
81 
82 
83  // interface
84 
85  public:
86 
87 
96  {
97  // GLOBAL SAFE ->
98  ::osl::MutexGuard aLock(SingletonRef::ownStaticLock());
99 
100  // must be increased before(!) the check is done.
101  // Otherwise this check can fail inside the same thread ...
102  ++m_nRef;
103  if (m_nRef == 1)
104  m_pInstance = new SingletonClass();
105 
106  OSL_ENSURE(m_nRef>0 && m_pInstance, "Race? Ref count of singleton >0, but instance is NULL!");
107  // <- GLOBAL SAFE
108  }
109 
110 
119  {
120  // GLOBAL SAFE ->
121  ::osl::MutexGuard aLock(SingletonRef::ownStaticLock());
122 
123  // must be decreased before(!) the check is done.
124  // Otherwise this check can fail inside the same thread ...
125  --m_nRef;
126  if (m_nRef == 0)
127  {
128  delete m_pInstance;
129  m_pInstance = NULL;
130  }
131  // <- GLOBAL SAFE
132  }
133 
134 
137  SingletonClass* operator->() const
138  {
139  // GLOBAL SAFE ->
140  ::osl::MutexGuard aLock(SingletonRef::ownStaticLock());
141  return m_pInstance;
142  // <- GLOBAL SAFE
143  }
144 
145 
148  SingletonClass& operator*() const
149  {
150  // GLOBAL SAFE ->
151  ::osl::MutexGuard aLock(SingletonRef::ownStaticLock());
152  return *m_pInstance;
153  // <- GLOBAL SAFE
154  }
155 
156 
157  // helper
158 
159  private:
160 
161 
168  struct SingletonLockInit
169  {
170  ::osl::Mutex* operator()()
171  {
172  static ::osl::Mutex aInstance;
173  return &aInstance;
174  }
175  };
176 
177  ::osl::Mutex& ownStaticLock() const
178  {
179  return *rtl_Instance< ::osl::Mutex,
180  SingletonLockInit,
182  ::osl::GetGlobalMutex >::create(SingletonLockInit(), ::osl::GetGlobalMutex());
183  }
184 };
185 
186 template< class SingletonClass >
187 SingletonClass* SingletonRef< SingletonClass >::m_pInstance = NULL;
188 
189 template< class SingletonClass >
190 sal_Int32 SingletonRef< SingletonClass >::m_nRef = 0;
191 
192 } // namespace salhelper
193 
194 #endif // INCLUDED_SALHELPER_SINGLETONREF_HXX
195 
196 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
A helper functor for the rtl_Instance template.
Definition: getglobalmutex.hxx:31
A mutual exclusion synchronization object.
Definition: mutex.hxx:30
SingletonRef()
standard ctor.
Definition: singletonref.hxx:95
template for implementing singleton classes.
Definition: singletonref.hxx:69
Guard< Mutex > MutexGuard
Definition: mutex.hxx:224
SingletonClass & operator*() const
Allows (*rSingle).someBodyOp().
Definition: singletonref.hxx:148
~SingletonRef()
standard dtor.
Definition: singletonref.hxx:118
#define OSL_ENSURE(c, m)
Definition: diagnose.h:101
SingletonClass * operator->() const
Allows rSingle-&gt;someBodyOp().
Definition: singletonref.hxx:137
A helper class for mutex objects and interfaces.
Definition: mutex.hxx:108