office-gobmx/dbaccess/source/ui/browser/AsyncronousLink.cxx

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// MARKER(update_precomp.py): autogen include statement, do not remove
#include "precompiled_dbaccess.hxx"
#ifndef DBAUI_ASYNCRONOUSLINK_HXX
#include "AsyncronousLink.hxx"
#endif
#ifndef _SV_SVAPP_HXX
#include <vcl/svapp.hxx>
#endif
#ifndef _TOOLS_DEBUG_HXX
#include <tools/debug.hxx>
#endif

//==================================================================
//= OAsyncronousLink
//==================================================================
using namespace dbaui;
DBG_NAME(OAsyncronousLink)
//------------------------------------------------------------------
OAsyncronousLink::OAsyncronousLink( const Link& _rHandler )
    :m_aHandler(_rHandler)
    ,m_aEventSafety()
    ,m_aDestructionSafety()
    ,m_nEventId(0)
{
    DBG_CTOR(OAsyncronousLink,NULL);
}

//------------------------------------------------------------------
OAsyncronousLink::~OAsyncronousLink()
{
    {
        ::osl::MutexGuard aEventGuard( m_aEventSafety );
        if ( m_nEventId )
            Application::RemoveUserEvent(m_nEventId);
        m_nEventId = 0;
    }

    {
        ::osl::MutexGuard aDestructionGuard( m_aDestructionSafety );
        // this is just for the case we're deleted while another thread just handled the event :
        // if this other thread called our link while we were deleting the event here, the
        // link handler blocked. With leaving the above block it continued, but now we are prevented
        // to leave this destructor 'til the link handler recognizes that nEvent == 0 and leaves.
    }
    DBG_DTOR(OAsyncronousLink,NULL);
}


//------------------------------------------------------------------
void OAsyncronousLink::Call( void* _pArgument )
{
    ::osl::MutexGuard aEventGuard( m_aEventSafety );
    if (m_nEventId)
        Application::RemoveUserEvent(m_nEventId);
    m_nEventId = Application::PostUserEvent( LINK( this, OAsyncronousLink, OnAsyncCall ), _pArgument );
}

//------------------------------------------------------------------
void OAsyncronousLink::CancelCall()
{
    ::osl::MutexGuard aEventGuard( m_aEventSafety );
    if ( m_nEventId )
        Application::RemoveUserEvent( m_nEventId );
    m_nEventId = 0;
}

//------------------------------------------------------------------
IMPL_LINK(OAsyncronousLink, OnAsyncCall, void*, _pArg)
{
    {
        ::osl::MutexGuard aDestructionGuard( m_aDestructionSafety );
        {
            ::osl::MutexGuard aEventGuard( m_aEventSafety );
            if (!m_nEventId)
                // our destructor deleted the event just while we we're waiting for m_aEventSafety
                // -> get outta here
                return 0;
            m_nEventId = 0;
        }
    }
    if (m_aHandler.IsSet())
        return m_aHandler.Call(_pArg);

    return 0L;
}