include/cppuhelper/weak.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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  19 #ifndef INCLUDED_CPPUHELPER_WEAK_HXX
  20 #define INCLUDED_CPPUHELPER_WEAK_HXX
  21
  22 #include <cassert>
  23 #include <cstddef>
  24 #include "osl/interlck.h"
  25 #include "rtl/alloc.h"
  26 #include "com/sun/star/uno/XWeak.hpp"
  27 #include "cppuhelper/cppuhelperdllapi.h"
  28
  29
  30 namespace cppu
  31 {
  32
  33 class OWeakConnectionPoint;
  34
  35 /** Base class to implement a UNO object supporting weak references, i.e. the object can be held
  36     weakly (by a css::uno::WeakReference).
  37     This implementation copes with reference counting.  Upon last release(), the virtual dtor
  38     is called.
  39
  40     @derive
  41     Inherit from this class and delegate acquire()/ release() calls.
  42 */
  43 class CPPUHELPER_DLLPUBLIC OWeakObject : public css::uno::XWeak
  44 {
  45     friend class OWeakConnectionPoint;
  46
  47 protected:
  48     /** Virtual dtor.
  49
  50         @attention
  51         Despite the fact that a RuntimeException is allowed to be thrown, you must not throw any
  52         exception upon destruction!
  53     */
  54     virtual ~OWeakObject() COVERITY_NOEXCEPT_FALSE;
  55
  56     /** disposes and resets m_pWeakConnectionPoint
  57         @pre
  58             m_refCount equals 0
  59     */
  60     void    disposeWeakConnectionPoint();
  61
  62     /** reference count.
  63
  64         @attention
  65         Don't modify manually!  Use acquire() and release().
  66     */
  67     oslInterlockedCount m_refCount;
  68
  69     /// @cond INTERNAL
  70
  71     /** Container of all weak reference listeners and the connection point from the weak reference.
  72     */
  73     OWeakConnectionPoint * m_pWeakConnectionPoint;
  74
  75     /** reserved for future use. do not use.
  76     */
  77     void * m_pReserved;
  78
  79     /// @endcond
  80
  81 public:
  82     /// @cond INTERNAL
  83     // these are here to force memory de/allocation to sal lib.
  84     static void * SAL_CALL operator new( size_t nSize )
  85         { return ::rtl_allocateMemory( nSize ); }
  86     static void SAL_CALL operator delete( void * pMem )
  87         { ::rtl_freeMemory( pMem ); }
  88     static void * SAL_CALL operator new( size_t, void * pMem )
  89         { return pMem; }
  90     static void SAL_CALL operator delete( void *, void * )
  91         {}
  92     /// @endcond
  93
  94 #ifdef _MSC_VER
  95     /** Default Constructor.  Sets the reference count to zero.
  96         Accidentally occurs in msvc mapfile = > had to be outlined.
  97     */
  98     OWeakObject();
  99 #else
 100     /** Default Constructor.  Sets the reference count to zero.
 101     */
 102     OWeakObject()
 103         : m_refCount( 0 )
 104         , m_pWeakConnectionPoint( NULL )
 105         , m_pReserved(NULL)
 106         {}
 107 #endif
 108     /** Dummy copy constructor.  Set the reference count to zero.
 109     */
 110     OWeakObject( const OWeakObject & )
 111         : css::uno::XWeak()
 112         , m_refCount( 0 )
 113         , m_pWeakConnectionPoint( NULL )
 114         , m_pReserved(NULL)
 115         {}
 116     /** Dummy assignment operator. Does not affect reference count.
 117
 118         @return this OWeakObject
 119     */
 120     OWeakObject & SAL_CALL operator = ( const OWeakObject &)
 121         { return *this; }
 122
 123     /** Basic queryInterface() implementation supporting com::sun::star::uno::XWeak and
 124         com::sun::star::uno::XInterface.
 125
 126         @param rType demanded type
 127         @return demanded type or empty any
 128     */
 129     virtual css::uno::Any SAL_CALL queryInterface(
 130         const css::uno::Type & rType ) SAL_OVERRIDE;
 131     /** increasing m_refCount
 132     */
 133     virtual void SAL_CALL acquire()
 134         throw () SAL_OVERRIDE;
 135     /** decreasing m_refCount
 136     */
 137     virtual void SAL_CALL release()
 138         throw () SAL_OVERRIDE;
 139
 140     /** XWeak::queryAdapter() implementation
 141
 142         @return a com::sun::star::uno::XAdapter reference
 143     */
 144     virtual css::uno::Reference< css::uno::XAdapter > SAL_CALL queryAdapter() SAL_OVERRIDE;
 145
 146     /** Cast operator to XInterface reference.
 147
 148         @return XInterface reference
 149     */
 150     SAL_CALL operator css::uno::Reference< css::uno::XInterface > ()
 151         { return this; }
 152 };
 153
 154 /// @cond INTERNAL
 155 /** Convenience function for constructor-based service implementations.
 156
 157     To be used like:
 158
 159     css::uno::XInterface * FOO_constructor_function(...) {
 160         return cppu::acquire(new FOO(...));
 161     }
 162
 163     @param instance
 164     Newly created instance that should be acquired.
 165 */
 166 static inline css::uno::XInterface * acquire(OWeakObject * instance)
 167 {
 168     assert(instance != NULL);
 169     instance->acquire();
 170     return instance;
 171 }
 172 /// @endcond
 173
 174 }
 175
 176 #endif
 177
 178 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */