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Qore Programming Language - C/C++ Library 1.19.2
ReferenceHolder.h
1 /* -*- mode: c++; indent-tabs-mode: nil -*- */
2 /*
3  ReferenceHolder.h
4 
5  Smart pointer like class that dereferences
6  obtained pointer to a QoreReferenceCounter in its destructor.
7 
8  Qore Programming Language
9 
10  Copyright (C) 2006 - 2023 Qore Technologies
11 
12  Permission is hereby granted, free of charge, to any person obtaining a
13  copy of this software and associated documentation files (the "Software"),
14  to deal in the Software without restriction, including without limitation
15  the rights to use, copy, modify, merge, publish, distribute, sublicense,
16  and/or sell copies of the Software, and to permit persons to whom the
17  Software is furnished to do so, subject to the following conditions:
18 
19  The above copyright notice and this permission notice shall be included in
20  all copies or substantial portions of the Software.
21 
22  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
28  DEALINGS IN THE SOFTWARE.
29 
30  Note that the Qore library is released under a choice of three open-source
31  licenses: MIT (as above), LGPL 2+, or GPL 2+; see README-LICENSE for more
32  information.
33 */
34 
35 #ifndef QORE_REFERENCE_HOLDER_H_
36 #define QORE_REFERENCE_HOLDER_H_
37 
38 #include <cstdlib>
39 #include <utility>
40 
42 
51 template<typename T = class AbstractQoreNode>
53 public:
55  DLLLOCAL ReferenceHolder(ExceptionSink* xsink_) : xsink(xsink_) {}
56 
58  DLLLOCAL ReferenceHolder(T* p_, ExceptionSink* xsink_) : p(p_), xsink(xsink_) {}
59 
61  DLLLOCAL ~ReferenceHolder() { if (p) p->deref(xsink);}
62 
64  DLLLOCAL T* operator->() { return p; }
65 
67  DLLLOCAL T* operator*() { return p; }
68 
70  DLLLOCAL const T* operator->() const { return p; }
71 
73  DLLLOCAL const T* operator*() const { return p; }
74 
76  DLLLOCAL void operator=(T *nv) {
77  if (p)
78  p->deref(xsink);
79  p = nv;
80  }
81 
83  DLLLOCAL T* release() {
84  T* rv = p;
85  p = nullptr;
86  return rv;
87  }
88 
90 
92  DLLLOCAL T* swap(T* val) {
93  T* rv = p;
94  p = val;
95  return rv;
96  }
97 
99  DLLLOCAL operator bool() const { return p != nullptr; }
100 
102  DLLLOCAL T** getPtrPtr() { return &p; }
103 
105  DLLLOCAL T*& getRef() { return p; }
106 
107 protected:
108  T* p = nullptr;
109  ExceptionSink* xsink;
110 
111 private:
112  ReferenceHolder(const ReferenceHolder&) = delete;
113  ReferenceHolder& operator=(const ReferenceHolder&) = delete;
114  void* operator new(size_t) = delete;
115 };
116 
118 
126 template<typename T = class SimpleQoreNode>
128 public:
129  DLLLOCAL SimpleRefHolder() {}
130  DLLLOCAL SimpleRefHolder(T* p_) : p(p_) {}
131 
133 
135  DLLLOCAL SimpleRefHolder(SimpleRefHolder&& old) : p(std::move(old.p)) {
136  old.p = nullptr;
137  }
138 
139  DLLLOCAL ~SimpleRefHolder() { if (p) p->deref(); }
140 
141  DLLLOCAL T* operator->() { return p; }
142  DLLLOCAL T* operator*() { return p; }
143  DLLLOCAL const T* operator->() const { return p; }
144  DLLLOCAL const T* operator*() const { return p; }
145  DLLLOCAL void operator=(T* nv) {
146  if (p)
147  p->deref();
148  p = nv;
149  }
150  DLLLOCAL T *release() {
151  T* rv = p;
152  p = nullptr;
153  return rv;
154  }
155 
157 
159  DLLLOCAL T* swap(T* val) {
160  T* rv = p;
161  p = val;
162  return rv;
163  }
164 
165  DLLLOCAL operator bool() const { return p != 0; }
166 
167 protected:
168  T* p = nullptr;
169 
170 private:
171  SimpleRefHolder(const SimpleRefHolder&) = delete;
172  SimpleRefHolder& operator=(const SimpleRefHolder&) = delete;
173  void* operator new(size_t) = delete;
174 };
175 
176 #endif
177 // EOF
container for holding Qore-language exception information and also for registering a "thread_exit" ca...
Definition: ExceptionSink.h:50
a templated class to manage a reference count of an object that can throw a Qore-language exception w...
Definition: ReferenceHolder.h:52
DLLLOCAL T * release()
releases the pointer to the caller
Definition: ReferenceHolder.h:83
DLLLOCAL ~ReferenceHolder()
calls deref(ExceptionSink *) on the pointer being managed if not 0
Definition: ReferenceHolder.h:61
DLLLOCAL T *& getRef()
returns a reference to the ptr being managed
Definition: ReferenceHolder.h:105
DLLLOCAL ReferenceHolder(ExceptionSink *xsink_)
creates an empty ReferenceHolder
Definition: ReferenceHolder.h:55
DLLLOCAL T * operator->()
returns the pointer being managed
Definition: ReferenceHolder.h:64
DLLLOCAL T ** getPtrPtr()
returns a pointer to the pointer being managed
Definition: ReferenceHolder.h:102
DLLLOCAL void operator=(T *nv)
assigns a new pointer to the holder, dereferences the current pointer if any
Definition: ReferenceHolder.h:76
DLLLOCAL T * swap(T *val)
swaps the current value for a new one
Definition: ReferenceHolder.h:92
DLLLOCAL T * operator*()
returns the pointer being managed
Definition: ReferenceHolder.h:67
manages a reference count of a pointer to a class that takes a simple "deref()" call with no argument...
Definition: ReferenceHolder.h:127
DLLLOCAL T * swap(T *val)
swaps the current value for a new one
Definition: ReferenceHolder.h:159