include/unotools/weakref.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 /*
  21  * This file is part of LibreOffice published API.
  22  */
  23 #pragma once
  24
  25 #include <sal/config.h>
  26
  27 #include <com/sun/star/uno/Reference.hxx>
  28 #include <com/sun/star/uno/XInterface.hpp>
  29 #include <cppuhelper/weakref.hxx>
  30 #include <cppuhelper/weak.hxx>
  31 #include <rtl/ref.hxx>
  32
  33 namespace cppu
  34 {
  35 class OWeakObject;
  36 }
  37
  38 namespace unotools
  39 {
  40 /** The WeakReference<> holds a weak reference to an object.
  41
  42     That object must implement the css::uno::XWeak interface.
  43
  44     The WeakReference itself is *not* thread safe, just as
  45     Reference itself isn't, but the implementation of the listeners etc.
  46     behind it *is* thread-safe, so multiple threads can have their own
  47     WeakReferences to the same XWeak object.
  48
  49     @tparam interface_type type of interface
  50 */
  51 template <class interface_type>
  52 class SAL_WARN_UNUSED WeakReference : public com::sun::star::uno::WeakReferenceHelper
  53 {
  54 public:
  55     /** Default ctor.  Creates an empty weak reference.
  56     */
  57     WeakReference()
  58         : WeakReferenceHelper()
  59     {
  60     }
  61
  62     /** Copy ctor.  Initialize this reference with a hard reference.
  63
  64         @param rRef another hard ref
  65     */
  66     WeakReference(const rtl::Reference<interface_type>& rRef)
  67         : WeakReferenceHelper(rRef)
  68     {
  69     }
  70
  71     /** Copy ctor.  Initialize this reference with a hard reference.
  72
  73         @param rRef another hard ref
  74     */
  75     WeakReference(interface_type& rRef)
  76         : WeakReferenceHelper(&rRef)
  77     {
  78     }
  79
  80     /** Copy ctor.  Initialize this reference with a hard reference.
  81
  82         @param rRef another hard ref
  83     */
  84     WeakReference(interface_type* pRef)
  85         : WeakReferenceHelper(static_cast<cppu::OWeakObject*>(pRef))
  86     {
  87     }
  88
  89     /** Releases this reference and takes over hard reference xInt.
  90         If the implementation behind xInt does not support XWeak
  91         or XInt is null, then this reference is null.
  92
  93         @param xInt another hard reference
  94     */
  95     WeakReference& operator=(const rtl::Reference<interface_type>& xInt)
  96     {
  97         WeakReferenceHelper::operator=(xInt);
  98         return *this;
  99     }
 100
 101     WeakReference& operator=(rtl::Reference<interface_type>&& xInt)
 102     {
 103         WeakReferenceHelper::operator=(std::move(xInt));
 104         return *this;
 105     }
 106
 107     WeakReference& operator=(interface_type* pInt)
 108     {
 109         WeakReferenceHelper::operator=(static_cast<::cppu::OWeakObject*>(pInt));
 110         return *this;
 111     }
 112
 113     /**  Gets a hard reference to the object.
 114
 115          @return hard reference or null, if the weakly referenced interface has gone
 116     */
 117     rtl::Reference<interface_type> SAL_CALL get() const
 118     {
 119         css::uno::Reference<css::uno::XInterface> xInterface = WeakReferenceHelper::get();
 120         return dynamic_cast<interface_type*>(xInterface.get());
 121     }
 122
 123     /**  Gets a hard reference to the object.
 124
 125          @return hard reference or null, if the weakly referenced interface has gone
 126     */
 127     operator ::rtl::Reference<interface_type>() const { return get(); }
 128 };
 129 }
 130
 131 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */