include/cppuhelper/weak.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.
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   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/.
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   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
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  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 #ifndef INCLUDED_CPPUHELPER_WEAK_HXX
  24 #define INCLUDED_CPPUHELPER_WEAK_HXX
  25
  26 #include <cassert>
  27 #include <cstddef>
  28 #include "osl/interlck.h"
  29 #include "rtl/alloc.h"
  30 #include "com/sun/star/uno/XWeak.hpp"
  31 #include "cppuhelper/cppuhelperdllapi.h"
  32
  33
  34 namespace cppu
  35 {
  36
  37 class OWeakConnectionPoint;
  38
  39 /** Base class to implement a UNO object supporting weak references, i.e. the object can be held
  40     weakly (by a css::uno::WeakReference).
  41     This implementation copes with reference counting.  Upon last release(), the virtual dtor
  42     is called.
  43
  44     @derive
  45     Inherit from this class and delegate acquire()/ release() calls.
  46 */
  47 class CPPUHELPER_DLLPUBLIC OWeakObject : public css::uno::XWeak
  48 {
  49     friend class OWeakConnectionPoint;
  50
  51 protected:
  52     /** Virtual dtor.
  53
  54         @attention
  55         Despite the fact that a RuntimeException is allowed to be thrown, you must not throw any
  56         exception upon destruction!
  57     */
  58     virtual ~OWeakObject() COVERITY_NOEXCEPT_FALSE;
  59
  60     /** disposes and resets m_pWeakConnectionPoint
  61         @pre
  62             m_refCount equals 0
  63     */
  64     void    disposeWeakConnectionPoint();
  65
  66     /** reference count.
  67
  68         @attention
  69         Don't modify manually!  Use acquire() and release().
  70     */
  71     oslInterlockedCount m_refCount;
  72
  73     /// @cond INTERNAL
  74
  75     /** Container of all weak reference listeners and the connection point from the weak reference.
  76     */
  77     OWeakConnectionPoint * m_pWeakConnectionPoint;
  78
  79     /** reserved for future use. do not use.
  80     */
  81     void * m_pReserved;
  82
  83     /// @endcond
  84
  85 public:
  86     /// @cond INTERNAL
  87     // these are here to force memory de/allocation to sal lib.
  88     static void * SAL_CALL operator new( size_t nSize )
  89         { return ::rtl_allocateMemory( nSize ); }
  90     static void SAL_CALL operator delete( void * pMem )
  91         { ::rtl_freeMemory( pMem ); }
  92     static void * SAL_CALL operator new( size_t, void * pMem )
  93         { return pMem; }
  94     static void SAL_CALL operator delete( void *, void * )
  95         {}
  96     /// @endcond
  97
  98     /** Default Constructor.  Sets the reference count to zero.
  99     */
 100     OWeakObject()
 101         : m_refCount( 0 )
 102         , m_pWeakConnectionPoint( NULL )
 103         , m_pReserved(NULL)
 104         {}
 105
 106     /** Dummy copy constructor.  Set the reference count to zero.
 107     */
 108     OWeakObject( const OWeakObject & )
 109         : css::uno::XWeak()
 110         , m_refCount( 0 )
 111         , m_pWeakConnectionPoint( NULL )
 112         , m_pReserved(NULL)
 113         {}
 114     /** Dummy assignment operator. Does not affect reference count.
 115
 116         @return this OWeakObject
 117     */
 118     OWeakObject & SAL_CALL operator = ( const OWeakObject &)
 119         { return *this; }
 120
 121     /** Basic queryInterface() implementation supporting com::sun::star::uno::XWeak and
 122         com::sun::star::uno::XInterface.
 123
 124         @param rType demanded type
 125         @return demanded type or empty any
 126     */
 127     virtual css::uno::Any SAL_CALL queryInterface(
 128         const css::uno::Type & rType ) SAL_OVERRIDE;
 129     /** increasing m_refCount
 130     */
 131     virtual void SAL_CALL acquire()
 132         SAL_NOEXCEPT SAL_OVERRIDE;
 133     /** decreasing m_refCount
 134     */
 135     virtual void SAL_CALL release()
 136         SAL_NOEXCEPT SAL_OVERRIDE;
 137
 138     /** XWeak::queryAdapter() implementation
 139
 140         @return a com::sun::star::uno::XAdapter reference
 141     */
 142     virtual css::uno::Reference< css::uno::XAdapter > SAL_CALL queryAdapter() SAL_OVERRIDE;
 143
 144     /** Cast operator to XInterface reference.
 145
 146         @return XInterface reference
 147     */
 148     SAL_CALL operator css::uno::Reference< css::uno::XInterface > ()
 149         { return this; }
 150
 151 #if defined LIBO_INTERNAL_ONLY
 152     css::uno::XWeak* getXWeak() { return this; }
 153 #endif
 154 };
 155
 156 /// @cond INTERNAL
 157 /** Convenience function for constructor-based service implementations.
 158
 159     To be used like:
 160
 161     css::uno::XInterface * FOO_constructor_function(...) {
 162         return cppu::acquire(new FOO(...));
 163     }
 164
 165     @param instance
 166     Newly created instance that should be acquired.
 167 */
 168 static inline css::uno::XInterface * acquire(OWeakObject * instance)
 169 {
 170     assert(instance != NULL);
 171     instance->acquire();
 172     return instance;
 173 }
 174
 175 #if defined LIBO_INTERNAL_ONLY
 176 static inline css::uno::XWeak* getXWeak(OWeakObject* instance) { return instance; }
 177 #endif
 178 /// @endcond
 179
 180 }
 181
 182 #endif
 183
 184 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */