Qore Programming Language  1.9.1
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 - 2022 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  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>
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
container for holding Qore-language exception information and also for registering a "thread_exit" ca...
Definition: ExceptionSink.h:48
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:96
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:93
DLLLOCAL void operator=(T *nv)
assigns a new pointer to the holder, dereferences the current pointer if any
Definition: ReferenceHolder.h:76
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:118