shlublu::Python::ObjectHandler Class Reference

Handler of CPython object pointers used by Python to handle references counts. More...

#include <Python_ObjectHandler.h>

Classes
class	Hasher
	Key hasher to be used with unordered containers such as std::unordered_map or std::unordered_set. More...

Public Member Functions
	ObjectHandler ()
	Empty constructor. More...
	ObjectHandler (ObjectHandler const &src)
	Copy constructor. More...
	ObjectHandler (ObjectHandler &&src) noexcept
	Move constructor. More...
	ObjectHandler (PyObject *pyObj)
	PyObject* constructor. More...
ObjectHandler &	operator= (ObjectHandler src) noexcept
	Assignment operator. More...
void	swap (ObjectHandler &other) noexcept
	Exchanges two instances. More...
PyObject *	get () const
	Returns the object pointer this handler encapsulates. More...
uint64_t	id () const
	Returns the ID of the use case represented by this handler. More...
	operator PyObject * () const
	PyObject* cast operator. More...

Detailed Description

Handler of CPython object pointers used by Python to handle references counts.

An instance represents a specific use of a given CPython object and is identified by an ID unique to this use case.

A given CPython object can be involved in several instances should it have several use cases at a given point of time.

Two copies of a same handler have the same object pointers and the same ID as they refer to the same use case.

ID is never zero but for empty instances.

Conversion from and to PyObject * is silent.

See also

PyObject

Typical examples of use

#include <iostream>
 
#include <shlublu/binding/Python.h>
 
using namespace shlublu;
 
int main(int, char* argv[])
{
    int retCode(0);
 
    try
    {
        Python::init(*argv);
        Python::execute("myFloat = 5.5");
        Python::ObjectHandler const& myFloat(Python::object(Python::moduleMain, "myFloat")); // Type 'Python::ObjectHandler const&' is explicit for this example though it is best to use `const auto`
 
        std::cout << PyFloat_AsDouble(myFloat) << std::endl; // 'Python::ObjectHandler' converts silently to CPython's 'PyObject *'
 
        const double anotherFloat(3.3);
 
        Python::controlArgument(PyFloat_FromDouble(anotherFloat)); // 'Python::ObjectHandler' is created silently from the CPython's 'PyObject *'
 
        // Python::shutdown() will dispose of this reference to the Python object created from anotherFloat
    }
    catch (Python::BindingException const& e)
    {
        std::cerr << "ERROR: " << e.what() << std::endl;
        retCode = -1;
    }
 
    return retCode;
}

Constructor & Destructor Documentation

ObjectHandler() [1/4]

shlublu::Python::ObjectHandler::ObjectHandler

(

)

Empty constructor.

Sets both object pointer and ID to zero.

ObjectHandler() [2/4]

shlublu::Python::ObjectHandler::ObjectHandler

(

ObjectHandler const &

src

)

Copy constructor.

Both object pointer and ID are copied.

Parameters

src	the instance to be copied.

ObjectHandler() [3/4]

shlublu::Python::ObjectHandler::ObjectHandler ( ObjectHandler &&  src )

noexcept

Move constructor.

Both object pointer and ID are moved.

Parameters

src	the instance to move in.

ObjectHandler() [4/4]

shlublu::Python::ObjectHandler::ObjectHandler

(

PyObject *

pyObj

)

PyObject* constructor.

Typically used as an implicit constructor for objects returned by the CPython API. An ID is allocated automatically at creation time.

Parameters

pyObj

the CPython object pointer this instance will be assigned.

See also

PyObject

Member Function Documentation

operator=()

ObjectHandler& shlublu::Python::ObjectHandler::operator= ( ObjectHandler  src )

noexcept

Assignment operator.

Should src be another instance, both object pointer and ID are copied. Should src be an object pointer, this pointer is copied and an ID is allocated automatically by an implied ObjectHandler.

Parameters

src	other instance or PyObject *

Returns

a reference to *this

swap()

void shlublu::Python::ObjectHandler::swap ( ObjectHandler &  other )

noexcept

Exchanges two instances.

Both object pointer and ID are swaped. Should src be an object pointer, an implied ObjectHandler is created and assigned an ID.

Parameters

other

other instance to swap with

get()

PyObject* shlublu::Python::ObjectHandler::get

(

)

const

Returns the object pointer this handler encapsulates.

Returns

a CPython object pointer

id()

uint64_t shlublu::Python::ObjectHandler::id

(

)

const

Returns the ID of the use case represented by this handler.

Returns

a use case ID

operator PyObject *()

shlublu::Python::ObjectHandler::operator PyObject *

(

)

const

PyObject* cast operator.

Typically used as an implicit cast operator to pass instances of ObjectHandler to functions of the CPython API.

Returns

the CPython object pointer this handler encapsulates.

See also

PyObject

---

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

• include/shlublu/binding/Python_ObjectHandler.h