Python::Reference Class Reference

Wrapper class for python objects. More...

#include <dune/fufem/python/reference.hh>

Inheritance diagram for Python::Reference:

Public Member Functions
	Reference ()
	Construct empty Reference.
	Reference (PyObject *p)
	Construct Reference from PyObject*.
	Reference (const Reference &other)
	Copy constructor.
virtual	~Reference ()
	Destructor.
virtual Reference &	operator= (const Reference &other)
	Assignment.
	operator PyObject * () const
	Access to stored reference.
template<class T >
void	toC (T &t) const
	Convert to C object.
template<class T >
std::enable_if< Conversion< T >::useDefaultConstructorConversion, T >::type	toC () const
	Convert to C object.
template<class T >
std::enable_if< Conversion< T >::useCustomConstructorConversion, T >::type	toC () const
	Convert to C object.
bool	hasAttr (const std::string &name) const
	Check if object has attribute of given name.
Reference	get (const std::string &name) const
	Query attribute of given name.
template<class V >
void	set (const std::string &name, const V &value)
	Set attribute of given name.
std::string	str () const
	String representation of this object.

Protected Member Functions
void	assertPyObject (const std::string &origin) const
	Assert that internal PyObject* is not NULL and raise exception otherwise.

Protected Attributes
PyObject *	p_

Detailed Description

Wrapper class for python objects.

This class wraps all python objects accessed or generated by the dune python interface. It hides all manual reference counting required by the python api from the user.

Since the internal reference counting is interesting if you want to extend the interface, e.g., by introducing conversions for new types, the details about the internal reference counting are documented where necessary. To avoid confusing the user this is marked 'For implementors:'

For implementors:

This class wraps a PyObject* in order to automate reference counting. Most methods of the python api return a PyObject* representing a new reference that is already counted internally. If you want to dispose such a reference you have to call Py_DECREF manually.

This class takes over ownership of such a new reference represented by PyObject* and calls Py_DECREF automatically on destruction. You can simply use Reference instead of PyObject* in all cases where new references are returned.

Furthermore it wraps some global python api methods as member functions.

A note about constness: We can in general not control constness from C correctly. Since the python api only uses non-const pointers we need to store a mutable pointer internally. Constness of the methods of this class is in general only a reasonable indicator. As obvious exception the call() method is marked const, while the python object might change. Even the get() method might change the python object if getattr is overloaded in python.

Constructor & Destructor Documentation

Reference() [1/3]

Python::Reference::Reference ( )

inline

Construct empty Reference.

Reference() [2/3]

Python::Reference::Reference ( PyObject *  p )

inline

Construct Reference from PyObject*.

Only to be used if you want to extend the interface using the python api.

For implementors:

Parameters

p	The pointer that will be owned by the Reference

Reference(p) steals a reference, i.e., it does always assume that the PyObject* p is a new reference as returned by most api methods. The Reference will take ownership i.e. the reference count will not be incremented but decremented on destruction.

Some api methods return borrowed references. In this case use Reference(Imp::inc(p)) to increment the reference count manually before wrapping.

Reference() [3/3]

Python::Reference::Reference ( const Reference &  other )

inline

Copy constructor.

For implementors:

This will increment the count for the stored reference.

~Reference()

virtual Python::Reference::~Reference ( )

inlinevirtual

Destructor.

For implementors:

This will decrement the count for the stored reference.

Member Function Documentation

assertPyObject()

void Python::Reference::assertPyObject ( const std::string &  origin ) const

inlineprotected

Assert that internal PyObject* is not NULL and raise exception otherwise.

Parameters

origin

A string describing the origin of the error

get()

Reference Python::Reference::get ( const std::string &  name ) const

inline

Query attribute of given name.

Parameters

name	Name of attribute

Returns

The attributes value as Reference

For implementors:

The count for the returned Reference is incremented.

hasAttr()

bool Python::Reference::hasAttr ( const std::string &  name ) const

inline

Check if object has attribute of given name.

Parameters

name	Name of attribute

operator PyObject *()

Python::Reference::operator PyObject * ( ) const

inline

Access to stored reference.

Return stored reference without changing its count. You can use this with all api methods that do not steal references.

Returns

A PyObject* representing a borrowed reference

operator=()

virtual Reference & Python::Reference::operator= ( const Reference &  other )

inlinevirtual

Assignment.

For implementors:

Decrements count for old reference and increments count for new reference.

Reimplemented in Python::Callable, and Python::Module.

set()

template<class V >

void Python::Reference::set ( const std::string &  name, const V &  value  )

inline

Set attribute of given name.

Parameters

name	Name of attribute
value	New value of attribute

For implementors:

This will not decrease the reference count for the Reference used as argument.

str()

std::string Python::Reference::str ( ) const

inline

String representation of this object.

toC() [1/3]

template<class T >

std::enable_if< Conversion< T >::useDefaultConstructorConversion, T >::type Python::Reference::toC ( ) const

inline

Convert to C object.

This does not change the reference count. This method uses the default constructor of T.

Template Parameters

T	C type for conversion

toC() [2/3]

template<class T >

std::enable_if< Conversion< T >::useCustomConstructorConversion, T >::type Python::Reference::toC ( ) const

inline

Convert to C object.

This does not change the reference count. This method uses a type dependent custom construct.

Template Parameters

T	C type for conversion

toC() [3/3]

template<class T >

void Python::Reference::toC ( T &  t ) const

inline

Convert to C object.

This does not change the reference count.

Template Parameters

T	C type for conversion

Parameters

t	Reference to store the result

Member Data Documentation

p_

PyObject* Python::Reference::p_

mutableprotected

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

• reference.hh