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27*cdf0e10cSrcweir 
28*cdf0e10cSrcweir #ifndef DBACCESS_CONNECTION_DEPENDENT_HXX
29*cdf0e10cSrcweir #define DBACCESS_CONNECTION_DEPENDENT_HXX
30*cdf0e10cSrcweir 
31*cdf0e10cSrcweir /** === begin UNO includes === **/
32*cdf0e10cSrcweir #include <com/sun/star/sdbc/XConnection.hpp>
33*cdf0e10cSrcweir #include <com/sun/star/lang/DisposedException.hpp>
34*cdf0e10cSrcweir /** === end UNO includes === **/
35*cdf0e10cSrcweir 
36*cdf0e10cSrcweir #include <comphelper/componentcontext.hxx>
37*cdf0e10cSrcweir #include <cppuhelper/weakref.hxx>
38*cdf0e10cSrcweir #include <osl/mutex.hxx>
39*cdf0e10cSrcweir 
40*cdf0e10cSrcweir //........................................................................
41*cdf0e10cSrcweir namespace sdbtools
42*cdf0e10cSrcweir {
43*cdf0e10cSrcweir //........................................................................
44*cdf0e10cSrcweir 
45*cdf0e10cSrcweir 	//====================================================================
46*cdf0e10cSrcweir 	//= ConnectionDependentComponent
47*cdf0e10cSrcweir 	//====================================================================
48*cdf0e10cSrcweir     class ConnectionDependentComponent
49*cdf0e10cSrcweir     {
50*cdf0e10cSrcweir     private:
51*cdf0e10cSrcweir         mutable ::osl::Mutex    m_aMutex;
52*cdf0e10cSrcweir         ::com::sun::star::uno::WeakReference< ::com::sun::star::sdbc::XConnection >
53*cdf0e10cSrcweir                                 m_aConnection;
54*cdf0e10cSrcweir         ::comphelper::ComponentContext
55*cdf0e10cSrcweir                                 m_aContext;
56*cdf0e10cSrcweir 
57*cdf0e10cSrcweir         /** a hard reference to the connection we're working for
58*cdf0e10cSrcweir 
59*cdf0e10cSrcweir             This member is only valid as long as a EntryGuard is on the stack.
60*cdf0e10cSrcweir             The guard will, in its constructor, set the member, and reset it in its destructor.
61*cdf0e10cSrcweir             This ensures that the connection is only held hard when it's needed, and weak otherwise.
62*cdf0e10cSrcweir         */
63*cdf0e10cSrcweir         ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >
64*cdf0e10cSrcweir                                 m_xConnection;
65*cdf0e10cSrcweir 
66*cdf0e10cSrcweir     protected:
67*cdf0e10cSrcweir         ::osl::Mutex&   getMutex() const { return m_aMutex; }
68*cdf0e10cSrcweir 
69*cdf0e10cSrcweir         const ::comphelper::ComponentContext&
70*cdf0e10cSrcweir                         getContext() const { return m_aContext; }
71*cdf0e10cSrcweir 
72*cdf0e10cSrcweir     protected:
73*cdf0e10cSrcweir         class EntryGuard;
74*cdf0e10cSrcweir 
75*cdf0e10cSrcweir     protected:
76*cdf0e10cSrcweir         ConnectionDependentComponent( const ::comphelper::ComponentContext& _rContext )
77*cdf0e10cSrcweir             :m_aContext( _rContext )
78*cdf0e10cSrcweir         {
79*cdf0e10cSrcweir         }
80*cdf0e10cSrcweir 
81*cdf0e10cSrcweir         /** sets the connection we depend on.
82*cdf0e10cSrcweir 
83*cdf0e10cSrcweir             To be called exactly once.
84*cdf0e10cSrcweir 
85*cdf0e10cSrcweir             @param  _rxConnection
86*cdf0e10cSrcweir                 the connection to set
87*cdf0e10cSrcweir         */
88*cdf0e10cSrcweir         void    setWeakConnection( const ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >& _rxConnection )
89*cdf0e10cSrcweir         {
90*cdf0e10cSrcweir             m_aConnection = _rxConnection;
91*cdf0e10cSrcweir         }
92*cdf0e10cSrcweir 
93*cdf0e10cSrcweir         const ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >&
94*cdf0e10cSrcweir                 getConnection() const { return m_xConnection; }
95*cdf0e10cSrcweir 
96*cdf0e10cSrcweir     public:
97*cdf0e10cSrcweir 	struct GuardAccess;
98*cdf0e10cSrcweir 	friend struct GuardAccess;
99*cdf0e10cSrcweir         /** helper for granting exclusive access to various other methods
100*cdf0e10cSrcweir         */
101*cdf0e10cSrcweir         struct GuardAccess { friend class EntryGuard; private: GuardAccess() { } };
102*cdf0e10cSrcweir 
103*cdf0e10cSrcweir         ::osl::Mutex&   getMutex( GuardAccess ) const { return m_aMutex; }
104*cdf0e10cSrcweir 
105*cdf0e10cSrcweir         inline bool acquireConnection( GuardAccess )
106*cdf0e10cSrcweir         {
107*cdf0e10cSrcweir             m_xConnection = (::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >)m_aConnection;
108*cdf0e10cSrcweir             return m_xConnection.is();
109*cdf0e10cSrcweir         }
110*cdf0e10cSrcweir         inline void releaseConnection( GuardAccess )
111*cdf0e10cSrcweir         {
112*cdf0e10cSrcweir             m_xConnection.clear();
113*cdf0e10cSrcweir         }
114*cdf0e10cSrcweir     };
115*cdf0e10cSrcweir 
116*cdf0e10cSrcweir 	//====================================================================
117*cdf0e10cSrcweir 	//= ConnectionDependentComponent::EntryGuard
118*cdf0e10cSrcweir 	//====================================================================
119*cdf0e10cSrcweir     /** a class for guarding methods of a connection-dependent component
120*cdf0e10cSrcweir 
121*cdf0e10cSrcweir         This class serves multiple purposes:
122*cdf0e10cSrcweir         <ul><li>It ensures multi-threading safety by guarding the component's mutex
123*cdf0e10cSrcweir                 as long as it lives.</li>
124*cdf0e10cSrcweir             <li>It ensures that the component's connection is alive. The constructor
125*cdf0e10cSrcweir                 throws a DisposedException if no hard reference to the connection can
126*cdf0e10cSrcweir                 be obtained.</li>
127*cdf0e10cSrcweir         </ul>
128*cdf0e10cSrcweir     */
129*cdf0e10cSrcweir     class ConnectionDependentComponent::EntryGuard
130*cdf0e10cSrcweir     {
131*cdf0e10cSrcweir     private:
132*cdf0e10cSrcweir         ::osl::MutexGuard               m_aMutexGuard;
133*cdf0e10cSrcweir         ConnectionDependentComponent&   m_rComponent;
134*cdf0e10cSrcweir 
135*cdf0e10cSrcweir     public:
136*cdf0e10cSrcweir         EntryGuard( ConnectionDependentComponent& _rComponent )
137*cdf0e10cSrcweir             :m_aMutexGuard( _rComponent.getMutex( ConnectionDependentComponent::GuardAccess() ) )
138*cdf0e10cSrcweir             ,m_rComponent( _rComponent )
139*cdf0e10cSrcweir         {
140*cdf0e10cSrcweir             if ( !m_rComponent.acquireConnection( ConnectionDependentComponent::GuardAccess() ) )
141*cdf0e10cSrcweir                 throw ::com::sun::star::lang::DisposedException();
142*cdf0e10cSrcweir         }
143*cdf0e10cSrcweir 
144*cdf0e10cSrcweir         ~EntryGuard()
145*cdf0e10cSrcweir         {
146*cdf0e10cSrcweir             m_rComponent.releaseConnection( ConnectionDependentComponent::GuardAccess() );
147*cdf0e10cSrcweir         }
148*cdf0e10cSrcweir     };
149*cdf0e10cSrcweir 
150*cdf0e10cSrcweir 
151*cdf0e10cSrcweir //........................................................................
152*cdf0e10cSrcweir } // namespace sdbtools
153*cdf0e10cSrcweir //........................................................................
154*cdf0e10cSrcweir 
155*cdf0e10cSrcweir #endif // DBACCESS_CONNECTION_DEPENDENT_HXX
156*cdf0e10cSrcweir 
157