lsst.log  22.0.0-5-gd2b0f3e+782b3b5ca8
PyObjectPtr.h
1 /*
2  * This file is part of log.
3  *
4  * Developed for the LSST Data Management System.
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6  * (https://www.lsst.org).
7  * See the COPYRIGHT file at the top-level directory of this distribution
8  * for details of code ownership.
9  *
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22  */
23 
24 #ifndef LSST_LOG_PYOBJECTPTR_H
25 #define LSST_LOG_PYOBJECTPTR_H
26 
27 // Python header has to be first to avoid compilation warnings
28 #include "Python.h"
29 
30 #include <cstddef>
31 
32 namespace lsst::log::detail {
33 
37 class PyObjectPtr {
38 public:
39 
43  static PyObjectPtr from_borrowed(PyObject* object) {
44  Py_XINCREF(object);
45  return PyObjectPtr(object);
46  }
47 
51  explicit PyObjectPtr(PyObject* object = nullptr) : m_object(object) {}
52 
53  // copy constructor, increments ref. counter
54  PyObjectPtr(PyObjectPtr const& other) : m_object(other.m_object) {
55  Py_XINCREF(m_object);
56  }
57 
58  // move constructor, steals reference
59  PyObjectPtr(PyObjectPtr&& other) : m_object(other.m_object) {
60  other.m_object = nullptr;
61  }
62 
63  // Decrement ref. counter
64  ~PyObjectPtr() { Py_CLEAR(m_object); }
65 
66  PyObjectPtr& operator=(PyObjectPtr const& other) {
67  Py_CLEAR(m_object);
68  m_object = other.m_object;
69  Py_XINCREF(m_object);
70  return *this;
71  }
72 
73  PyObjectPtr& operator=(PyObjectPtr&& other) {
74  Py_CLEAR(m_object);
75  m_object = other.m_object;
76  other.m_object = nullptr;
77  return *this;
78  }
79 
80  PyObjectPtr& operator=(PyObject* object) {
81  Py_CLEAR(m_object);
82  m_object = object;
83  Py_XINCREF(m_object);
84  return *this;
85  }
86 
87  // can be converted to regular pointer
88  operator PyObject*() const { return m_object; }
89 
90  // release ownership
91  PyObject* release() {
92  auto object = m_object;
93  m_object = nullptr;
94  return object;
95  }
96 
97  // This returns a reference so you can take a pointer of a pointer, needed
98  // for some API methods.
99  PyObject*& get() { return m_object; }
100 
101  // compare to nullptr
102  bool operator==(nullptr_t) const { return m_object == nullptr; }
103  bool operator!=(nullptr_t) const { return m_object != nullptr; }
104 
105 private:
106 
107  PyObject* m_object = nullptr;
108 };
109 
110 } // namespace lsst::log::detail
111 
112 #endif // LSST_LOG_PYOBJECTPTR_H
Definition: PyObjectPtr.h:37
static PyObjectPtr from_borrowed(PyObject *object)
Definition: PyObjectPtr.h:43
PyObjectPtr(PyObject *object=nullptr)
Definition: PyObjectPtr.h:51