office-gobmx/dbaccess/source/sdbtools/connection/connectiondependent.hxx

156 lines
5.7 KiB
C++

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*
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*
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License version 3 for more details
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*
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#ifndef DBACCESS_CONNECTION_DEPENDENT_HXX
#define DBACCESS_CONNECTION_DEPENDENT_HXX
/** === begin UNO includes === **/
#include <com/sun/star/sdbc/XConnection.hpp>
#include <com/sun/star/lang/DisposedException.hpp>
/** === end UNO includes === **/
#include <comphelper/componentcontext.hxx>
#include <cppuhelper/weakref.hxx>
#include <osl/mutex.hxx>
//........................................................................
namespace sdbtools
{
//........................................................................
//====================================================================
//= ConnectionDependentComponent
//====================================================================
class ConnectionDependentComponent
{
private:
mutable ::osl::Mutex m_aMutex;
::com::sun::star::uno::WeakReference< ::com::sun::star::sdbc::XConnection >
m_aConnection;
::comphelper::ComponentContext
m_aContext;
/** a hard reference to the connection we're working for
This member is only valid as long as a EntryGuard is on the stack.
The guard will, in its constructor, set the member, and reset it in its destructor.
This ensures that the connection is only held hard when it's needed, and weak otherwise.
*/
::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >
m_xConnection;
protected:
::osl::Mutex& getMutex() const { return m_aMutex; }
const ::comphelper::ComponentContext&
getContext() const { return m_aContext; }
protected:
class EntryGuard;
protected:
ConnectionDependentComponent( const ::comphelper::ComponentContext& _rContext )
:m_aContext( _rContext )
{
}
/** sets the connection we depend on.
To be called exactly once.
@param _rxConnection
the connection to set
*/
void setWeakConnection( const ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >& _rxConnection )
{
m_aConnection = _rxConnection;
}
const ::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >&
getConnection() const { return m_xConnection; }
public:
struct GuardAccess;
friend struct GuardAccess;
/** helper for granting exclusive access to various other methods
*/
struct GuardAccess { friend class EntryGuard; private: GuardAccess() { } };
::osl::Mutex& getMutex( GuardAccess ) const { return m_aMutex; }
inline bool acquireConnection( GuardAccess )
{
m_xConnection = (::com::sun::star::uno::Reference< ::com::sun::star::sdbc::XConnection >)m_aConnection;
return m_xConnection.is();
}
inline void releaseConnection( GuardAccess )
{
m_xConnection.clear();
}
};
//====================================================================
//= ConnectionDependentComponent::EntryGuard
//====================================================================
/** a class for guarding methods of a connection-dependent component
This class serves multiple purposes:
<ul><li>It ensures multi-threading safety by guarding the component's mutex
as long as it lives.</li>
<li>It ensures that the component's connection is alive. The constructor
throws a DisposedException if no hard reference to the connection can
be obtained.</li>
</ul>
*/
class ConnectionDependentComponent::EntryGuard
{
private:
::osl::MutexGuard m_aMutexGuard;
ConnectionDependentComponent& m_rComponent;
public:
EntryGuard( ConnectionDependentComponent& _rComponent )
:m_aMutexGuard( _rComponent.getMutex( ConnectionDependentComponent::GuardAccess() ) )
,m_rComponent( _rComponent )
{
if ( !m_rComponent.acquireConnection( ConnectionDependentComponent::GuardAccess() ) )
throw ::com::sun::star::lang::DisposedException();
}
~EntryGuard()
{
m_rComponent.releaseConnection( ConnectionDependentComponent::GuardAccess() );
}
};
//........................................................................
} // namespace sdbtools
//........................................................................
#endif // DBACCESS_CONNECTION_DEPENDENT_HXX