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pyOverride.h
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2 // Copyright 2016 Pixar
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24 #ifndef TF_PYOVERRIDE_H
25 #define TF_PYOVERRIDE_H
26 
27 #include "pxr/pxr.h"
28 
29 #include "pxr/base/tf/pyLock.h"
30 #include "pxr/base/tf/pyObjWrapper.h"
31 
32 #include <boost/python/override.hpp>
33 
34 PXR_NAMESPACE_OPEN_SCOPE
35 
46 {
47 private:
49  friend class TfPyOverride;
50  explicit TfPyMethodResult(PyObject* x)
51  : m_obj(x)
52  {}
53 
54 public:
56  TfPyMethodResult(TfPyMethodResult const &other);
57 
60 
63 
64  template <class T>
65  operator T()
66  {
67  TfPyLock lock;
68  boost::python::converter::return_from_python<T> converter;
69  return converter(m_obj.release());
70  }
71 
72  template <class T>
73  operator T&() const
74  {
75  TfPyLock lock;
76  boost::python::converter::return_from_python<T&> converter;
77  return converter(
78  const_cast<boost::python::handle<>&>(m_obj).release());
79  }
80 
81  template <class T>
82  T as(boost::type<T>* = 0)
83  {
84  TfPyLock lock;
85  boost::python::converter::return_from_python<T> converter;
86  return converter(m_obj.release());
87  }
88 
89  template <class T>
90  T unchecked(boost::type<T>* = 0)
91  {
92  TfPyLock lock;
93  return boost::python::extract<T>(m_obj)();
94  }
95 
96 private:
97  mutable boost::python::handle<> m_obj;
98 };
99 
115 {
116  // Helper to generate Py_BuildValue-style format strings at compile time.
117  template <typename Arg>
118  constexpr static char _PyObjArg()
119  {
120  return 'O';
121  }
122 
123 public:
125  TfPyOverride(boost::python::handle<> callable)
126  : TfPyObjWrapper(boost::python::object(callable))
127  {}
128 
131  template <typename... Args>
133  operator()(Args const&... args) const
134  {
135  TfPyLock lock;
136  // Use the Args parameter pack together with the _PyObjArg helper to
137  // unpack the right number of 'O' elements into the format string.
138  static const char pyCallFormat[] =
139  { '(', _PyObjArg<Args>()..., ')', '\0' };
140 
142  PyEval_CallFunction(
143  this->ptr(),
144  const_cast<char*>(pyCallFormat),
145  boost::python::converter::arg_to_python<Args>(args).get()...));
146  return x;
147  }
148 };
149 
150 PXR_NAMESPACE_CLOSE_SCOPE
151 
152 #endif // TF_PYOVERRIDE_H
TF_API PyObject * ptr() const
Underlying PyObject* access.
TfPyMethodResult & operator=(TfPyMethodResult const &other)
Implement assign to do python refcounting while holding the GIL.
TfPyMethodResult operator()(Args const &...args) const
Call the override.
Definition: pyOverride.h:133
TfPyOverride(boost::python::handle<> callable)
Clients must hold the GIL to construct.
Definition: pyOverride.h:125
A reimplementation of boost::python::override.
Definition: pyOverride.h:114
~TfPyMethodResult()
Implement dtor to do python refcounting while holding the GIL.
Boost Python object wrapper.
Definition: pyObjWrapper.h:66
A reimplementation of boost::python::detail::method_result.
Definition: pyOverride.h:45