vsg: include/vsg/core/observer_ptr.h Source File

vsg 1.1.10 VulkanSceneGraph library |

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observer_ptr.h
1#pragma once
2
3/* <editor-fold desc="MIT License">
4
5Copyright(c) 2018 Robert Osfield
6
7Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
8
9The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
10
11THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
12
13</editor-fold> */
14
15#include <vsg/core/Auxiliary.h>
16
17namespace vsg
18{
19
22 template<class T>
23 class observer_ptr
24 {
25 public:
26 using element_type = T;
27
28 observer_ptr() :
29 _ptr(nullptr) {}
30
31 observer_ptr(const observer_ptr& rhs) :
32 _ptr(rhs._ptr),
33 _auxiliary(rhs._auxiliary)
34 {
35 }
36
37 template<class R>
38 explicit observer_ptr(R* ptr) :
39 _ptr(ptr),
40 _auxiliary(ptr ? ptr->getOrCreateAuxiliary() : nullptr)
41 {
42 }
43
44 template<class R>
45 explicit observer_ptr(const observer_ptr<R>& ptr) :
46 _ptr(ptr._ptr),
47 _auxiliary(ptr._auxiliary)
48 {
49 }
50
51 template<class R>
52 explicit observer_ptr(const vsg::ref_ptr<R>& ptr) :
53 _ptr(ptr.get()),
54 _auxiliary(ptr.valid() ? ptr->getOrCreateAuxiliary() : nullptr)
55 {
56 }
57
58 ~observer_ptr()
59 {
60 }
61
62 void reset()
63 {
64 _ptr = nullptr;
65 _auxiliary.reset();
66 }
67
68 template<class R>
69 observer_ptr& operator=(R* ptr)
70 {
71 _ptr = ptr;
72 _auxiliary = ptr ? ptr->getOrCreateAuxiliary() : nullptr;
73 return *this;
74 }
75
76 observer_ptr& operator=(const observer_ptr& rhs)
77 {
78 _ptr = rhs._ptr;
79 _auxiliary = rhs._auxiliary;
80 return *this;
81 }
82
83 template<class R>
84 observer_ptr& operator=(const observer_ptr<R>& rhs)
85 {
86 _ptr = rhs._ptr;
87 _auxiliary = rhs._auxiliary;
88 return *this;
89 }
90
91 template<class R>
92 observer_ptr& operator=(const vsg::ref_ptr<R>& rhs)
93 {
94 _ptr = rhs.get();
95 _auxiliary = rhs.valid() ? rhs->getOrCreateAuxiliary() : nullptr;
96 return *this;
97 }
98
99 template<class R>
100 bool operator<(const observer_ptr<R>& rhs) const { return (rhs._ptr < _ptr); }
101
102 template<class R>
103 bool operator==(const observer_ptr<R>& rhs) const { return (rhs._ptr == _ptr); }
104
105 template<class R>
106 bool operator!=(const observer_ptr<R>& rhs) const { return (rhs._ptr != _ptr); }
107
108 template<class R>
109 bool operator<(const R* rhs) const { return (rhs < _ptr); }
110
111 template<class R>
112 bool operator==(const R* rhs) const { return (rhs == _ptr); }
113
114 template<class R>
115 bool operator!=(const R* rhs) const { return (rhs != _ptr); }
116
117 bool valid() const noexcept { return _auxiliary.valid() && _auxiliary->getConnectedObject() != nullptr; }
118
119 explicit operator bool() const noexcept { return valid(); }
120
122 vsg::ref_ptr<T> ref_ptr() const { return vsg::ref_ptr<T>(*this); }
123
125 template<class R>
126 operator vsg::ref_ptr<R>() const
127 {
128 if (!_auxiliary) return vsg::ref_ptr<R>();
129
130 std::scoped_lock<std::mutex> guard(_auxiliary->getMutex());
131 if (_auxiliary->getConnectedObject() != nullptr)
132 return vsg::ref_ptr<R>(_ptr);
133 else
134 return {};
135 }
136
137 protected:
138 template<class R>
139 friend class observer_ptr;
140
141 T* _ptr;
142 vsg::ref_ptr<Auxiliary> _auxiliary;
143 };
144
145} // namespace vsg
vsg::observer_ptr
Definition observer_ptr.h:24
vsg::observer_ptr::ref_ptr
vsg::ref_ptr< T > ref_ptr() const
convert observer_ptr into a ref_ptr so that Object pointed to can be safely accessed.
Definition observer_ptr.h:122
vsg::ref_ptr
Definition ref_ptr.h:22