lsst::utils::python::PySharedPtr< T > Class Template Reference

A shared pointer that tracks both a C++ object and its associated PyObject. More...

#include <PySharedPtr.h>

Public Types
using	element_type = T

Public Member Functions
	PySharedPtr (T *const ptr)
	Create a pointer that counts as an extra reference in the Python environment. More...
	PySharedPtr (PySharedPtr const &) noexcept=default
	PySharedPtr (PySharedPtr &&) noexcept=default
PySharedPtr &	operator= (PySharedPtr const &) noexcept=default
PySharedPtr &	operator= (PySharedPtr &&) noexcept=default
	~PySharedPtr () noexcept=default
	PySharedPtr (std::shared_ptr< T > r) noexcept
	operator std::shared_ptr< T > () noexcept
T *	get () const noexcept

Detailed Description

template<typename T>
class lsst::utils::python::PySharedPtr< T >

A shared pointer that tracks both a C++ object and its associated PyObject.

Each group of PySharedPtr for a given object collectively counts as one reference to that object for the purpose of Python garbage collection.

A PySharedPtr is implicitly convertible to and from a std::shared_ptr to minimize API impact. Any shared_ptr created this way will (I think) keep the Python reference alive, as described above.

Definition at line 49 of file PySharedPtr.h.

Member Typedef Documentation

element_type

template<typename T >

using lsst::utils::python::PySharedPtr< T >::element_type = T

Definition at line 51 of file PySharedPtr.h.

Constructor & Destructor Documentation

PySharedPtr() [1/4]

template<typename T >

lsst::utils::python::PySharedPtr< T >::PySharedPtr ( T *const  ptr )

inlineexplicit

Create a pointer that counts as an extra reference in the Python environment.

Parameters

ptr	a pointer to a pybind11-managed object.

Definition at line 59 of file PySharedPtr.h.

                                       : _impl() {
        if (ptr != nullptr) {
            // `cast` returns new PyObject only if `*ptr` not yet associated with one
            PyObject* pyObj = pybind11::cast(ptr).ptr();
            Py_INCREF(pyObj);
            // if any operation with shared_ptr fails, pyObj will get decremented correctly
            std::shared_ptr<PyObject> manager(pyObj, [](PyObject* const obj) noexcept {
                if (obj != nullptr) Py_DECREF(obj);
            });
            _impl = std::shared_ptr<T>(manager, ptr);
        }
    }

PySharedPtr() [2/4]

template<typename T >

lsst::utils::python::PySharedPtr< T >::PySharedPtr ( PySharedPtr< T > const &  )

defaultnoexcept

PySharedPtr() [3/4]

template<typename T >

lsst::utils::python::PySharedPtr< T >::PySharedPtr ( PySharedPtr< T > &&  )

defaultnoexcept

~PySharedPtr()

template<typename T >

lsst::utils::python::PySharedPtr< T >::~PySharedPtr ( )

defaultnoexcept

PySharedPtr() [4/4]

template<typename T >

lsst::utils::python::PySharedPtr< T >::PySharedPtr ( std::shared_ptr< T >  r )

inlinenoexcept

Definition at line 78 of file PySharedPtr.h.

: _impl(std::move(r)) {}

Member Function Documentation

get()

template<typename T >

T* lsst::utils::python::PySharedPtr< T >::get ( ) const

inlinenoexcept

Definition at line 81 of file PySharedPtr.h.

{ return _impl.get(); }

operator std::shared_ptr< T >()

template<typename T >

lsst::utils::python::PySharedPtr< T >::operator std::shared_ptr< T > ( )

inlinenoexcept

Definition at line 79 of file PySharedPtr.h.

{ return _impl; }

operator=() [1/2]

template<typename T >

PySharedPtr& lsst::utils::python::PySharedPtr< T >::operator= ( PySharedPtr< T > const &  )

defaultnoexcept

operator=() [2/2]

template<typename T >

PySharedPtr& lsst::utils::python::PySharedPtr< T >::operator= ( PySharedPtr< T > &&  )

defaultnoexcept

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The documentation for this class was generated from the following file:

• /j/snowflake/release/lsstsw/stack/Linux64/utils/19.0.0-3-g2d13df8/include/lsst/utils/python/PySharedPtr.h