| Qore Programming Language - C/C++ Library 1.0.8

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 - 2020 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>
52 class ReferenceHolder {
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 DLLLOCAL operator bool() const { return p != nullptr; }
91
93 DLLLOCAL T** getPtrPtr() { return &p; }
94
96 DLLLOCAL T*& getRef() { return p; }
97
98 protected:
99 T* p = nullptr;
100 ExceptionSink* xsink;
101
102 private:
103 ReferenceHolder(const ReferenceHolder&) = delete;
104 ReferenceHolder& operator=(const ReferenceHolder&) = delete;
105 void* operator new(size_t) = delete;
106 };
107
109
117 template<typename T = class SimpleQoreNode>
118 class SimpleRefHolder {
119 public:
120 DLLLOCAL SimpleRefHolder() {}
121 DLLLOCAL SimpleRefHolder(T* p_) : p(p_) {}
122
124
126 DLLLOCAL SimpleRefHolder(SimpleRefHolder&& old) : p(std::move(old.p)) {
127 old.p = nullptr;
128 }
129
130 DLLLOCAL ~SimpleRefHolder() { if (p) p->deref(); }
131
132 DLLLOCAL T* operator->() { return p; }
133 DLLLOCAL T* operator*() { return p; }
134 DLLLOCAL const T* operator->() const { return p; }
135 DLLLOCAL const T* operator*() const { return p; }
136 DLLLOCAL void operator=(T* nv) {
137 if (p)
138 p->deref();
139 p = nv;
140 }
141 DLLLOCAL T *release() {
142 T* rv = p;
143 p = nullptr;
144 return rv;
145 }
146 DLLLOCAL operator bool() const { return p != 0; }
147
148 protected:
149 T* p = nullptr;
150
151 private:
152 SimpleRefHolder(const SimpleRefHolder&) = delete;
153 SimpleRefHolder& operator=(const SimpleRefHolder&) = delete;
154 void* operator new(size_t) = delete;
155 };
156
157 #endif
158 // EOF
ReferenceHolder::getPtrPtr
DLLLOCAL T ** getPtrPtr()
returns a pointer to the pointer being managed
Definition: ReferenceHolder.h:93
std
STL namespace.
ReferenceHolder::release
DLLLOCAL T * release()
releases the pointer to the caller
Definition: ReferenceHolder.h:83
ReferenceHolder::operator*
DLLLOCAL T * operator*()
returns the pointer being managed
Definition: ReferenceHolder.h:67
ReferenceHolder::~ReferenceHolder
DLLLOCAL ~ReferenceHolder()
calls deref(ExceptionSink *) on the pointer being managed if not 0
Definition: ReferenceHolder.h:61
ReferenceHolder::getRef
DLLLOCAL T *& getRef()
returns a reference to the ptr being managed
Definition: ReferenceHolder.h:96
ExceptionSink
container for holding Qore-language exception information and also for registering a "thread_exit" ca...
Definition: ExceptionSink.h:48
SimpleRefHolder
manages a reference count of a pointer to a class that takes a simple "deref()" call with no argument...
Definition: ReferenceHolder.h:118
ReferenceHolder::operator->
DLLLOCAL T * operator->()
returns the pointer being managed
Definition: ReferenceHolder.h:64
ReferenceHolder::ReferenceHolder
DLLLOCAL ReferenceHolder(ExceptionSink *xsink_)
creates an empty ReferenceHolder
Definition: ReferenceHolder.h:55
ReferenceHolder::operator=
DLLLOCAL void operator=(T *nv)
assigns a new pointer to the holder, dereferences the current pointer if any
Definition: ReferenceHolder.h:76
ReferenceHolder
a templated class to manage a reference count of an object that can throw a Qore-language exception w...
Definition: ReferenceHolder.h:52