dbaccess/source/ui/browser/AsynchronousLink.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #include <dbaccess/AsynchronousLink.hxx>
  21 #include <vcl/svapp.hxx>
  22 #include <tools/debug.hxx>
  23
  24 // OAsynchronousLink
  25 using namespace dbaui;
  26 OAsynchronousLink::OAsynchronousLink( const Link<>& _rHandler )
  27     :m_aHandler(_rHandler)
  28     ,m_aEventSafety()
  29     ,m_aDestructionSafety()
  30     ,m_nEventId(0)
  31 {
  32 }
  33
  34 OAsynchronousLink::~OAsynchronousLink()
  35 {
  36     {
  37         ::osl::MutexGuard aEventGuard( m_aEventSafety );
  38         if ( m_nEventId )
  39             Application::RemoveUserEvent(m_nEventId);
  40         m_nEventId = 0;
  41     }
  42
  43     {
  44         ::osl::MutexGuard aDestructionGuard( m_aDestructionSafety );
  45         // this is just for the case we're deleted while another thread just handled the event :
  46         // if this other thread called our link while we were deleting the event here, the
  47         // link handler blocked. With leaving the above block it continued, but now we are prevented
  48         // to leave this destructor 'til the link handler recognizes that nEvent == 0 and leaves.
  49     }
  50 }
  51
  52 void OAsynchronousLink::Call( void* _pArgument )
  53 {
  54     ::osl::MutexGuard aEventGuard( m_aEventSafety );
  55     if (m_nEventId)
  56         Application::RemoveUserEvent(m_nEventId);
  57     m_nEventId = Application::PostUserEvent( LINK( this, OAsynchronousLink, OnAsyncCall ), _pArgument );
  58 }
  59
  60 void OAsynchronousLink::CancelCall()
  61 {
  62     ::osl::MutexGuard aEventGuard( m_aEventSafety );
  63     if ( m_nEventId )
  64         Application::RemoveUserEvent( m_nEventId );
  65     m_nEventId = 0;
  66 }
  67
  68 IMPL_LINK(OAsynchronousLink, OnAsyncCall, void*, _pArg)
  69 {
  70     {
  71         ::osl::MutexGuard aDestructionGuard( m_aDestructionSafety );
  72         {
  73             ::osl::MutexGuard aEventGuard( m_aEventSafety );
  74             if (!m_nEventId)
  75                 // our destructor deleted the event just while we are waiting for m_aEventSafety
  76                 // -> get outta here
  77                 return 0;
  78             m_nEventId = 0;
  79         }
  80     }
  81     if (m_aHandler.IsSet())
  82         return m_aHandler.Call(_pArg);
  83
  84     return 0L;
  85 }
  86
  87 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */