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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 : : #ifndef _SALHELPER_SIMPLEREFERENCEOBJECT_HXX_
21 : : #define _SALHELPER_SIMPLEREFERENCEOBJECT_HXX_
22 : :
23 : : #include "osl/interlck.h"
24 : : #include "sal/types.h"
25 : : #include "salhelperdllapi.h"
26 : :
27 : : #include <cstddef>
28 : : #include <new>
29 : :
30 : : namespace salhelper {
31 : :
32 : : /** A simple base implementation for reference-counted objects.
33 : :
34 : : Classes that want to implement a reference-counting mechanism based on the
35 : : acquire()/release() interface should derive from this class.
36 : :
37 : : The reason to have class local operators new and delete here is technical.
38 : : Imagine a class D derived from SimpleReferenceObject, but implemented in
39 : : another shared library that happens to use different global operators new
40 : : and delete from those used in this shared library (which, sadly, seems to
41 : : be possible with shared libraries). Now, without the class local
42 : : operators new and delete here, a code sequence like "new D" would use the
43 : : global operator new as found in the other shared library, while the code
44 : : sequence "delete this" in release() would use the global operator delete
45 : : as found in this shared library---and these two operators would not be
46 : : guaranteed to match.
47 : :
48 : : There are no overloaded operators new and delete for placement new here,
49 : : because it is felt that the concept of placement new does not work well
50 : : with the concept of reference-counted objects; so it seems best to simply
51 : : leave those operators out.
52 : :
53 : : The same problem as with operators new and delete would also be there with
54 : : operators new[] and delete[]. But since arrays of reference-counted
55 : : objects are of no use, anyway, it seems best to simply declare and not
56 : : define (private) operators new[] and delete[].
57 : : */
58 : : class SALHELPER_DLLPUBLIC SimpleReferenceObject
59 : : {
60 : : public:
61 : 16145727 : inline SimpleReferenceObject() SAL_THROW(()): m_nCount(0) {}
62 : :
63 : : /** @attention
64 : : The results are undefined if, for any individual instance of
65 : : SimpleReferenceObject, the total number of calls to acquire() exceeds
66 : : the total number of calls to release() by a platform dependent amount
67 : : (which, hopefully, is quite large).
68 : : */
69 : 108347055 : inline void acquire() SAL_THROW(())
70 : 108347055 : { osl_incrementInterlockedCount(&m_nCount); }
71 : :
72 : 108277585 : inline void release() SAL_THROW(())
73 [ + + ][ + - ]: 108277585 : { if (osl_decrementInterlockedCount(&m_nCount) == 0) delete this; }
74 : :
75 : : /** see general class documentation
76 : : */
77 : : static void * operator new(std::size_t nSize) SAL_THROW((std::bad_alloc));
78 : :
79 : : /** see general class documentation
80 : : */
81 : : static void * operator new(std::size_t nSize,
82 : : std::nothrow_t const & rNothrow)
83 : : SAL_THROW(());
84 : :
85 : : /** see general class documentation
86 : : */
87 : : static void operator delete(void * pPtr) SAL_THROW(());
88 : :
89 : : /** see general class documentation
90 : : */
91 : : static void operator delete(void * pPtr, std::nothrow_t const & rNothrow)
92 : : SAL_THROW(());
93 : :
94 : : protected:
95 : : virtual ~SimpleReferenceObject() SAL_THROW(());
96 : :
97 : : private:
98 : : oslInterlockedCount m_nCount;
99 : :
100 : : /** not implemented
101 : : */
102 : : SALHELPER_DLLPRIVATE SimpleReferenceObject(SimpleReferenceObject &);
103 : :
104 : : /** not implemented
105 : : */
106 : : SALHELPER_DLLPRIVATE void operator =(SimpleReferenceObject);
107 : :
108 : : /// @cond INTERNAL
109 : :
110 : : #ifdef _MSC_VER
111 : : /* We can't now have these private with MSVC2008 at least, it leads to
112 : : compilation errors in xmloff and other places.
113 : : */
114 : : protected:
115 : : #endif
116 : : /** not implemented (see general class documentation)
117 : : */
118 : : static void * operator new[](std::size_t);
119 : :
120 : : /** not implemented (see general class documentation)
121 : : */
122 : : static void operator delete[](void * pPtr);
123 : :
124 : : /// @endcond
125 : : };
126 : :
127 : : }
128 : :
129 : : #endif // _SALHELPER_SIMPLEREFERENCEOBJECT_HXX_
130 : :
131 : : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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