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
  23 // OAsynchronousLink
  24 using namespace dbaui;
  25 OAsynchronousLink::OAsynchronousLink(const Link<void*, void>& _rHandler)
  26     : m_aHandler(_rHandler)
  27     , m_nEventId(nullptr)
  28 {
  29 }
  30
  31 OAsynchronousLink::~OAsynchronousLink()
  32 {
  33     {
  34         std::unique_lock aEventGuard(m_aEventSafety);
  35         if (m_nEventId)
  36             Application::RemoveUserEvent(m_nEventId);
  37         m_nEventId = nullptr;
  38     }
  39
  40     {
  41         std::unique_lock aDestructionGuard(m_aDestructionSafety);
  42         // this is just for the case we're deleted while another thread just handled the event :
  43         // if this other thread called our link while we were deleting the event here, the
  44         // link handler blocked. With leaving the above block it continued, but now we are prevented
  45         // to leave this destructor 'til the link handler recognizes that nEvent == 0 and leaves.
  46     }
  47 }
  48
  49 void OAsynchronousLink::Call(void* _pArgument)
  50 {
  51     std::unique_lock aEventGuard(m_aEventSafety);
  52     if (m_nEventId)
  53         Application::RemoveUserEvent(m_nEventId);
  54     m_nEventId = Application::PostUserEvent(LINK(this, OAsynchronousLink, OnAsyncCall), _pArgument);
  55 }
  56
  57 void OAsynchronousLink::CancelCall()
  58 {
  59     std::unique_lock aEventGuard(m_aEventSafety);
  60     if (m_nEventId)
  61         Application::RemoveUserEvent(m_nEventId);
  62     m_nEventId = nullptr;
  63 }
  64
  65 IMPL_LINK(OAsynchronousLink, OnAsyncCall, void*, _pArg, void)
  66 {
  67     {
  68         std::unique_lock aDestructionGuard(m_aDestructionSafety);
  69         {
  70             std::unique_lock aEventGuard(m_aEventSafety);
  71             if (!m_nEventId)
  72                 // our destructor deleted the event just while we are waiting for m_aEventSafety
  73                 // -> get outta here
  74                 return;
  75             m_nEventId = nullptr;
  76         }
  77     }
  78     m_aHandler.Call(_pArg);
  79 }
  80
  81 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */