framework/source/inc/loadenv/actionlockguard.hxx

   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 #pragma once
  21
  22 #include <com/sun/star/document/XActionLockable.hpp>
  23 #include <mutex>
  24
  25 namespace framework{
  26
  27 /** @short  implements a guard, which can use the interface
  28             <type scope="css::document">XActionLockable</type>.
  29
  30     @descr  This guard should be used to be sure, that any lock will be
  31             released. Otherwise the locked document can hinder the office on shutdown!
  32 */
  33 class ActionLockGuard final
  34 {
  35
  36     // member
  37
  38     private:
  39         std::mutex m_mutex;
  40
  41         /** @short  points to the object, which can be locked from outside. */
  42         css::uno::Reference< css::document::XActionLockable > m_xActionLock;
  43
  44         /** @short  knows if a lock exists on the internal lock object
  45                     forced by this guard instance. */
  46         bool m_bActionLocked;
  47
  48     // interface
  49
  50     public:
  51
  52         /** @short  default ctor to initialize a "non working guard".
  53
  54             @descr  That can be useful in cases, where no resource still exists,
  55                     but will be available next time. Then this guard can be used
  56                     in a mode "use guard for more than one resources".
  57          */
  58         ActionLockGuard()
  59             : m_bActionLocked(false)
  60         {
  61         }
  62
  63         /** @short  release this guard instance and make sure, that no lock
  64                     will exist afterwards on the internal wrapped resource.
  65          */
  66         ~ActionLockGuard()
  67         {
  68             unlock();
  69         }
  70
  71         /** @short  set a new resource for locking at this guard.
  72
  73             @descr  This call will fail, if an internal resource already exists
  74                     and is currently locked.
  75
  76             @param  xLock
  77                     points to the outside resource, which should be locked.
  78
  79             @return sal_True, if new resource could be set and locked.
  80                     sal_False otherwise.
  81          */
  82         bool setResource(const css::uno::Reference< css::document::XActionLockable >& xLock)
  83         {
  84             std::unique_lock g(m_mutex);
  85
  86             if (m_bActionLocked || !xLock.is())
  87                 return false;
  88
  89             m_xActionLock = xLock;
  90             m_xActionLock->addActionLock();
  91             m_bActionLocked = m_xActionLock->isActionLocked();
  92
  93             return true;
  94         }
  95
  96         /** @short  set a new resource for locking at this guard.
  97
  98             @descr  This call will fail, if an internal resource already exists
  99                     and is currently locked.
 100
 101             @param  xLock
 102                     points to the outside resource, which should be locked.
 103
 104             @return sal_True, if new resource could be set and locked.
 105                     sal_False otherwise.
 106          */
 107         void freeResource()
 108         {
 109             // SAFE -> ..........................
 110             std::unique_lock aMutexLock(m_mutex);
 111
 112             css::uno::Reference< css::document::XActionLockable > xLock   = m_xActionLock;
 113             bool                                                  bLocked = m_bActionLocked;
 114
 115             m_xActionLock.clear();
 116             m_bActionLocked = false;
 117
 118             aMutexLock.unlock();
 119             // <- SAFE ..........................
 120
 121             if (bLocked && xLock.is())
 122                 xLock->removeActionLock();
 123         }
 124
 125         /** @short  unlock the internal wrapped resource, if it's not already done. */
 126         void unlock()
 127         {
 128             std::unique_lock g(m_mutex);
 129             if (m_bActionLocked && m_xActionLock.is())
 130             {
 131                 m_xActionLock->removeActionLock();
 132                 // don't check for any locks here ...
 133                 // May another guard use the same lock object :-(
 134                 m_bActionLocked = false;
 135             }
 136         }
 137 };
 138
 139 } // namespace framework
 140
 141 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */