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refBase.h
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2 // Copyright 2016 Pixar
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5 // with the following modification; you may not use this file except in
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24 #ifndef PXR_BASE_TF_REF_BASE_H
25 #define PXR_BASE_TF_REF_BASE_H
26 
27 /// \file tf/refBase.h
28 /// \ingroup group_tf_Memory
29 
30 #include "pxr/pxr.h"
31 
32 #include "pxr/base/tf/refCount.h"
33 #include "pxr/base/tf/api.h"
34 
36 
37 template <class T> class TfRefPtr;
38 template <class T> class TfWeakPtr;
39 
40 /// \class TfRefBase
41 /// \ingroup group_tf_Memory
42 ///
43 /// Enable a concrete base class for use with \c TfRefPtr.
44 ///
45 /// You should be familiar with the \c TfRefPtr type before reading further.
46 ///
47 /// A class (but not an interface class) is enabled for reference
48 /// counting via the \c TfRefPtr type by publicly deriving from \c
49 /// TfRefBase.
50 ///
51 /// For example,
52 /// \code
53 /// #include "pxr/base/tf/refPtr.h"
54 ///
55 /// class Simple : public TfRefBase {
56 /// public:
57 /// TfRefPtr<Simple> New() {
58 /// return TfCreateRefPtr(new Simple);
59 /// }
60 /// private:
61 /// Simple();
62 /// };
63 /// \endcode
64 ///
65 /// The class \c Simple can now only be manipulated in terms of
66 /// a \c TfRefPtr<Simple>.
67 ///
68 /// To disable the cost of the "unique changed" system, derive
69 /// from TfSimpleRefBase instead.
70 ///
71 class TfRefBase {
72 public:
73 
74  typedef void (*UniqueChangedFuncPtr)(TfRefBase const *, bool);
76  void (*lock)();
78  void (*unlock)();
79  };
80 
81  TfRefBase() : _shouldInvokeUniqueChangedListener(false) { }
82 
83  /// Return the current reference count of this object.
84  size_t GetCurrentCount() const {
85  return GetRefCount().Get();
86  }
87 
88  /// Return true if only one \c TfRefPtr points to this object.
89  bool IsUnique() const {
90  return GetRefCount().Get() == 1;
91  }
92 
93  const TfRefCount& GetRefCount() const {
94  return _refCount;
95  }
96 
97  void SetShouldInvokeUniqueChangedListener(bool shouldCall) {
98  _shouldInvokeUniqueChangedListener = shouldCall;
99  }
100 
101  TF_API static void SetUniqueChangedListener(UniqueChangedListener listener);
102 
103 protected:
104  /*
105  * Prohibit deletion through a TfRefBase pointer.
106  */
107  TF_API virtual ~TfRefBase();
108 
109 private:
110  TfRefCount _refCount;
111  bool _shouldInvokeUniqueChangedListener;
112 
113  static UniqueChangedListener _uniqueChangedListener;
114  template <typename T> friend class TfRefPtr;
116  friend struct Tf_RefPtr_Counter;
117 
118  template <typename T> friend TfRefPtr<T>
120 };
121 
122 /// \class TfSimpleRefBase
123 /// \ingroup group_tf_Memory
124 ///
125 /// Enable a concrete base class for use with \c TfRefPtr that inhibits the
126 /// "unique changed" facility of TfRefPtr.
127 ///
128 /// Derive from this class if you don't plan on wrapping your
129 /// reference-counted object via hboost::python.
130 ///
131 class TfSimpleRefBase : public TfRefBase {
132 public:
133  TF_API virtual ~TfSimpleRefBase();
134 };
135 
137 
138 #endif // PXR_BASE_TF_REF_BASE_H
bool IsUnique() const
Return true if only one TfRefPtr points to this object.
Definition: refBase.h:89
#define TF_API
Definition: api.h:40
const TfRefCount & GetRefCount() const
Definition: refBase.h:93
friend TfRefPtr< T > TfCreateRefPtrFromProtectedWeakPtr(TfWeakPtr< T > const &)
Definition: weakPtr.h:262
virtual TF_API ~TfRefBase()
void(* UniqueChangedFuncPtr)(TfRefBase const *, bool)
Definition: refBase.h:74
virtual TF_API ~TfSimpleRefBase()
void
Definition: png.h:1083
UniqueChangedFuncPtr func
Definition: refBase.h:77
static TF_API void SetUniqueChangedListener(UniqueChangedListener listener)
size_t GetCurrentCount() const
Return the current reference count of this object.
Definition: refBase.h:84
PXR_NAMESPACE_CLOSE_SCOPE PXR_NAMESPACE_OPEN_SCOPE
Definition: path.h:1346
#define PXR_NAMESPACE_CLOSE_SCOPE
Definition: pxr.h:91
int Get() const
Returns counter's value.
Definition: refCount.h:85
void SetShouldInvokeUniqueChangedListener(bool shouldCall)
Definition: refBase.h:97
TfRefBase()
Definition: refBase.h:81