All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Macros Groups Pages
refCount.h
Go to the documentation of this file.
1 //
2 // Copyright 2016 Pixar
3 //
4 // Licensed under the Apache License, Version 2.0 (the "Apache License")
5 // with the following modification; you may not use this file except in
6 // compliance with the Apache License and the following modification to it:
7 // Section 6. Trademarks. is deleted and replaced with:
8 //
9 // 6. Trademarks. This License does not grant permission to use the trade
10 // names, trademarks, service marks, or product names of the Licensor
11 // and its affiliates, except as required to comply with Section 4(c) of
12 // the License and to reproduce the content of the NOTICE file.
13 //
14 // You may obtain a copy of the Apache License at
15 //
16 // http://www.apache.org/licenses/LICENSE-2.0
17 //
18 // Unless required by applicable law or agreed to in writing, software
19 // distributed under the Apache License with the above modification is
20 // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
21 // KIND, either express or implied. See the Apache License for the specific
22 // language governing permissions and limitations under the Apache License.
23 //
24 #ifndef TF_REFCOUNT_H
25 #define TF_REFCOUNT_H
26 
29 
30 #include "pxr/pxr.h"
31 
32 #include "pxr/base/arch/inttypes.h"
33 #include "pxr/base/tf/api.h"
34 #include <atomic>
35 
36 PXR_NAMESPACE_OPEN_SCOPE
37 
38 template <typename T> class TfRefPtr;
39 
71 class TfRefCount {
72 public:
74  TfRefCount() : _counter(1) {
75  }
76 
81  TfRefCount(const TfRefCount&) : _counter(1) {
82  }
83 
85  int Get() const {
86  return _counter;
87  }
88 
90  const TfRefCount& operator=(const TfRefCount&) const {
91  return *this;
92  }
93 private:
95  bool _DecrementAndTestIfZero() const {
96  return (--_counter == 0);
97  }
98 
100  int _FetchAndAdd(int amount) const {
101  return _counter.fetch_add(amount);
102  }
103 
104 private:
105  mutable std::atomic<int> _counter;
106  template <typename T> friend class TfRefPtr;
107  friend struct Tf_RefPtr_UniqueChangedCounter;
108  friend struct Tf_RefPtr_Counter;
109 };
110 
111 PXR_NAMESPACE_CLOSE_SCOPE
112 
113 #endif // TF_REFCOUNT_H
const TfRefCount & operator=(const TfRefCount &) const
Assignment to a reference counter has no effect.
Definition: refCount.h:90
int Get() const
Returns counter&#39;s value.
Definition: refCount.h:85
Reference counter class.
Definition: refCount.h:71
TfRefCount()
Initialize counter to one.
Definition: refCount.h:74
TfRefCount(const TfRefCount &)
Initialize counter to one.
Definition: refCount.h:81
Reference-counted smart pointer utility class.
Definition: hash.h:45