include/osl/mutex.hxx

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  19
  20 #ifndef INCLUDED_OSL_MUTEX_HXX
  21 #define INCLUDED_OSL_MUTEX_HXX
  22
  23 #include <osl/mutex.h>
  24
  25
  26 namespace osl
  27 {
  28     /** A mutual exclusion synchronization object
  29     */
  30     class SAL_WARN_UNUSED Mutex {
  31
  32     public:
  33         /** Create a mutex.
  34             @return 0 if the mutex could not be created, otherwise a handle to the mutex.
  35             @see ::osl_createMutex()
  36         */
  37         Mutex()
  38         {
  39             mutex = osl_createMutex();
  40         }
  41
  42         /** Release the OS-structures and free mutex data-structure.
  43             @see ::osl_destroyMutex()
  44         */
  45         ~Mutex()
  46         {
  47             osl_destroyMutex(mutex);
  48         }
  49
  50         /** Acquire the mutex, block if already acquired by another thread.
  51             @return false if system-call fails.
  52             @see ::osl_acquireMutex()
  53         */
  54         bool acquire()
  55         {
  56             return osl_acquireMutex(mutex);
  57         }
  58
  59         /** Try to acquire the mutex without blocking.
  60             @return false if it could not be acquired.
  61             @see ::osl_tryToAcquireMutex()
  62         */
  63         bool tryToAcquire()
  64         {
  65             return osl_tryToAcquireMutex(mutex);
  66         }
  67
  68         /** Release the mutex.
  69             @return false if system-call fails.
  70             @see ::osl_releaseMutex()
  71         */
  72         bool release()
  73         {
  74             return osl_releaseMutex(mutex);
  75         }
  76
  77         /** Returns a global static mutex object.
  78             The global and static mutex object can be used to initialize other
  79             static objects in a thread safe manner.
  80             @return the global mutex object
  81             @see ::osl_getGlobalMutex()
  82         */
  83         static Mutex * getGlobalMutex()
  84         {
  85             return reinterpret_cast<Mutex *>(osl_getGlobalMutex());
  86         }
  87
  88     private:
  89         oslMutex mutex;
  90
  91         /** The underlying oslMutex has no reference count.
  92
  93         Since the underlying oslMutex is not a reference counted object, copy
  94         constructed Mutex may work on an already destructed oslMutex object.
  95
  96         */
  97         Mutex(const Mutex&) SAL_DELETED_FUNCTION;
  98
  99         /** This assignment operator is deleted for the same reason as
 100             the copy constructor.
 101         */
 102         Mutex& operator= (const Mutex&) SAL_DELETED_FUNCTION;
 103     };
 104
 105     /** A helper class for mutex objects and interfaces.
 106     */
 107     template<class T>
 108     class Guard
 109     {
 110     private:
 111         Guard( const Guard& ) SAL_DELETED_FUNCTION;
 112         const Guard& operator = ( const Guard& ) SAL_DELETED_FUNCTION;
 113
 114     protected:
 115         T * pT;
 116     public:
 117
 118         /** Acquires the object specified as parameter.
 119         */
 120         Guard(T * pT_) : pT(pT_)
 121         {
 122             pT->acquire();
 123         }
 124
 125         /** Acquires the object specified as parameter.
 126         */
 127         Guard(T & t) : pT(&t)
 128         {
 129             pT->acquire();
 130         }
 131
 132         /** Releases the mutex or interface. */
 133         ~Guard()
 134         {
 135             pT->release();
 136         }
 137     };
 138
 139     /** A helper class for mutex objects and interfaces.
 140     */
 141     template<class T>
 142     class ClearableGuard
 143     {
 144     private:
 145         ClearableGuard( const ClearableGuard& ) SAL_DELETED_FUNCTION;
 146         const ClearableGuard& operator = ( const ClearableGuard& )
 147             SAL_DELETED_FUNCTION;
 148     protected:
 149         T * pT;
 150     public:
 151
 152         /** Acquires the object specified as parameter.
 153         */
 154         ClearableGuard(T * pT_) : pT(pT_)
 155         {
 156             pT->acquire();
 157         }
 158
 159         /** Acquires the object specified as parameter.
 160         */
 161         ClearableGuard(T & t) : pT(&t)
 162         {
 163             pT->acquire();
 164         }
 165
 166         /** Releases the mutex or interface if not already released by clear().
 167         */
 168         ~ClearableGuard()
 169         {
 170             if (pT)
 171                 pT->release();
 172         }
 173
 174         /** Releases the mutex or interface.
 175         */
 176         void clear()
 177         {
 178             if(pT)
 179             {
 180                 pT->release();
 181                 pT = NULL;
 182             }
 183         }
 184     };
 185
 186     /** A helper class for mutex objects and interfaces.
 187     */
 188     template< class T >
 189     class ResettableGuard : public ClearableGuard< T >
 190     {
 191     private:
 192         ResettableGuard(ResettableGuard &) SAL_DELETED_FUNCTION;
 193         void operator =(ResettableGuard &) SAL_DELETED_FUNCTION;
 194
 195     protected:
 196         T* pResetT;
 197     public:
 198         /** Acquires the object specified as parameter.
 199         */
 200         ResettableGuard( T* pT_ ) :
 201                 ClearableGuard<T>( pT_ ),
 202                 pResetT( pT_ )
 203         {}
 204
 205         /** Acquires the object specified as parameter.
 206         */
 207         ResettableGuard( T& rT ) :
 208                 ClearableGuard<T>( rT ),
 209                 pResetT( &rT )
 210         {}
 211
 212         /** Re-acquires the mutex or interface.
 213         */
 214         void reset()
 215         {
 216             if( pResetT )
 217             {
 218                 this->pT = pResetT;
 219                 this->pT->acquire();
 220             }
 221         }
 222     };
 223
 224     typedef Guard<Mutex> MutexGuard;
 225     typedef ClearableGuard<Mutex> ClearableMutexGuard;
 226     typedef ResettableGuard< Mutex > ResettableMutexGuard;
 227 }
 228
 229 #endif // INCLUDED_OSL_MUTEX_HXX
 230
 231 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */