Current File : //usr/lib/python3/dist-packages/gi/types.py
# -*- Mode: Python; py-indent-offset: 4 -*-
# vim: tabstop=4 shiftwidth=4 expandtab
#
# Copyright (C) 2005-2009 Johan Dahlin <johan@gnome.org>
#
# types.py: base types for introspected items.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
# USA
import re
from ._constants import TYPE_INVALID
from .docstring import generate_doc_string
from ._gi import \
InterfaceInfo, \
ObjectInfo, \
StructInfo, \
VFuncInfo, \
register_interface_info, \
hook_up_vfunc_implementation, \
GInterface
from . import _gi
StructInfo, GInterface # pyflakes
from . import _propertyhelper as propertyhelper
from . import _signalhelper as signalhelper
def snake_case(name):
s1 = re.sub('(.)([A-Z][a-z]+)', r'\1_\2', name)
return re.sub('([a-z0-9])([A-Z])', r'\1_\2', s1).lower()
class MetaClassHelper(object):
def _setup_methods(cls):
for method_info in cls.__info__.get_methods():
setattr(cls, method_info.__name__, method_info)
def _setup_class_methods(cls):
info = cls.__info__
class_struct = info.get_class_struct()
if class_struct is None:
return
for method_info in class_struct.get_methods():
name = method_info.__name__
# Don't mask regular methods or base class methods with TypeClass methods.
if not hasattr(cls, name):
setattr(cls, name, classmethod(method_info))
def _setup_fields(cls):
for field_info in cls.__info__.get_fields():
name = field_info.get_name().replace('-', '_')
setattr(cls, name, property(field_info.get_value, field_info.set_value))
def _setup_constants(cls):
for constant_info in cls.__info__.get_constants():
name = constant_info.get_name()
value = constant_info.get_value()
setattr(cls, name, value)
def _setup_vfuncs(cls):
for vfunc_name, py_vfunc in cls.__dict__.items():
if not vfunc_name.startswith("do_") or not callable(py_vfunc):
continue
skip_ambiguity_check = False
# If a method name starts with "do_" assume it is a vfunc, and search
# in the base classes for a method with the same name to override.
# Recursion is necessary as overriden methods in most immediate parent
# classes may shadow vfuncs from classes higher in the hierarchy.
vfunc_info = None
for base in cls.__mro__:
method = getattr(base, vfunc_name, None)
if method is not None and isinstance(method, VFuncInfo):
vfunc_info = method
break
if not hasattr(base, '__info__') or not hasattr(base.__info__, 'get_vfuncs'):
continue
base_name = snake_case(base.__info__.get_type_name())
for v in base.__info__.get_vfuncs():
if vfunc_name == 'do_%s_%s' % (base_name, v.get_name()):
vfunc_info = v
skip_ambiguity_check = True
break
if vfunc_info:
break
# If we did not find a matching method name in the bases, we might
# be overriding an interface virtual method. Since interfaces do not
# provide implementations, there will be no method attribute installed
# on the object. Instead we have to search through
# InterfaceInfo.get_vfuncs(). Note that the infos returned by
# get_vfuncs() use the C vfunc name (ie. there is no "do_" prefix).
if vfunc_info is None:
vfunc_info = find_vfunc_info_in_interface(cls.__bases__, vfunc_name[len("do_"):])
if vfunc_info is not None:
# Check to see if there are vfuncs with the same name in the bases.
# We have no way of specifying which one we are supposed to override.
if not skip_ambiguity_check:
ambiguous_base = find_vfunc_conflict_in_bases(vfunc_info, cls.__bases__)
if ambiguous_base is not None:
base_info = vfunc_info.get_container()
raise TypeError('Method %s() on class %s.%s is ambiguous '
'with methods in base classes %s.%s and %s.%s' %
(vfunc_name,
cls.__info__.get_namespace(),
cls.__info__.get_name(),
base_info.get_namespace(),
base_info.get_name(),
ambiguous_base.__info__.get_namespace(),
ambiguous_base.__info__.get_name()
))
hook_up_vfunc_implementation(vfunc_info, cls.__gtype__,
py_vfunc)
def _setup_native_vfuncs(cls):
# Only InterfaceInfo and ObjectInfo have the get_vfuncs() method.
# We skip InterfaceInfo because interfaces have no implementations for vfuncs.
# Also check if __info__ in __dict__, not hasattr('__info__', ...)
# because we do not want to accidentally retrieve __info__ from a base class.
class_info = cls.__dict__.get('__info__')
if class_info is None or not isinstance(class_info, ObjectInfo):
return
# Special case skipping of vfuncs for GObject.Object because they will break
# the static bindings which will try to use them.
if cls.__module__ == 'gi.repository.GObject' and cls.__name__ == 'Object':
return
for vfunc_info in class_info.get_vfuncs():
name = 'do_%s' % vfunc_info.__name__
setattr(cls, name, vfunc_info)
def find_vfunc_info_in_interface(bases, vfunc_name):
for base in bases:
# All wrapped interfaces inherit from GInterface.
# This can be seen in IntrospectionModule.__getattr__() in module.py.
# We do not need to search regular classes here, only wrapped interfaces.
# We also skip GInterface, because it is not wrapped and has no __info__ attr.
# Skip bases without __info__ (static _gi.GObject)
if base is GInterface or\
not issubclass(base, GInterface) or\
not hasattr(base, '__info__'):
continue
# Only look at this classes vfuncs if it is an interface.
if isinstance(base.__info__, InterfaceInfo):
for vfunc in base.__info__.get_vfuncs():
if vfunc.get_name() == vfunc_name:
return vfunc
# Recurse into the parent classes
vfunc = find_vfunc_info_in_interface(base.__bases__, vfunc_name)
if vfunc is not None:
return vfunc
return None
def find_vfunc_conflict_in_bases(vfunc, bases):
for klass in bases:
if not hasattr(klass, '__info__') or \
not hasattr(klass.__info__, 'get_vfuncs'):
continue
vfuncs = klass.__info__.get_vfuncs()
vfunc_name = vfunc.get_name()
for v in vfuncs:
if v.get_name() == vfunc_name and v != vfunc:
return klass
aklass = find_vfunc_conflict_in_bases(vfunc, klass.__bases__)
if aklass is not None:
return aklass
return None
class _GObjectMetaBase(type):
"""Metaclass for automatically registering GObject classes."""
def __init__(cls, name, bases, dict_):
type.__init__(cls, name, bases, dict_)
propertyhelper.install_properties(cls)
signalhelper.install_signals(cls)
cls._type_register(cls.__dict__)
def _type_register(cls, namespace):
# don't register the class if already registered
if '__gtype__' in namespace:
return
# Do not register a new GType for the overrides, as this would sort of
# defeat the purpose of overrides...
if cls.__module__.startswith('gi.overrides.'):
return
_gi.type_register(cls, namespace.get('__gtype_name__'))
_gi._install_metaclass(_GObjectMetaBase)
class GObjectMeta(_GObjectMetaBase, MetaClassHelper):
"""Meta class used for GI GObject based types."""
def __init__(cls, name, bases, dict_):
super(GObjectMeta, cls).__init__(name, bases, dict_)
is_gi_defined = False
if cls.__module__ == 'gi.repository.' + cls.__info__.get_namespace():
is_gi_defined = True
is_python_defined = False
if not is_gi_defined and cls.__module__ != GObjectMeta.__module__:
is_python_defined = True
if is_python_defined:
cls._setup_vfuncs()
elif is_gi_defined:
if isinstance(cls.__info__, ObjectInfo):
cls._setup_class_methods()
cls._setup_methods()
cls._setup_constants()
cls._setup_native_vfuncs()
if isinstance(cls.__info__, ObjectInfo):
cls._setup_fields()
elif isinstance(cls.__info__, InterfaceInfo):
register_interface_info(cls.__info__.get_g_type())
def mro(cls):
return mro(cls)
@property
def __doc__(cls):
"""Meta class property which shows up on any class using this meta-class."""
if cls == GObjectMeta:
return ''
doc = cls.__dict__.get('__doc__', None)
if doc is not None:
return doc
# For repository classes, dynamically generate a doc string if it wasn't overridden.
if cls.__module__.startswith(('gi.repository.', 'gi.overrides')):
return generate_doc_string(cls.__info__)
return None
def mro(C):
"""Compute the class precedence list (mro) according to C3, with GObject
interface considerations.
We override Python's MRO calculation to account for the fact that
GObject classes are not affected by the diamond problem:
http://en.wikipedia.org/wiki/Diamond_problem
Based on http://www.python.org/download/releases/2.3/mro/
"""
# TODO: If this turns out being too slow, consider using generators
bases = []
bases_of_subclasses = [[C]]
if C.__bases__:
for base in C.__bases__:
# Python causes MRO's to be calculated starting with the lowest
# base class and working towards the descendant, storing the result
# in __mro__ at each point. Therefore at this point we know that
# we already have our base class MRO's available to us, there is
# no need for us to (re)calculate them.
bases_of_subclasses += [list(base.__mro__)]
bases_of_subclasses += [list(C.__bases__)]
while bases_of_subclasses:
for subclass_bases in bases_of_subclasses:
candidate = subclass_bases[0]
not_head = [s for s in bases_of_subclasses if candidate in s[1:]]
if not_head and GInterface not in candidate.__bases__:
candidate = None # conflict, reject candidate
else:
break
if candidate is None:
raise TypeError('Cannot create a consistent method resolution '
'order (MRO)')
bases.append(candidate)
for subclass_bases in bases_of_subclasses[:]: # remove candidate
if subclass_bases and subclass_bases[0] == candidate:
del subclass_bases[0]
if not subclass_bases:
bases_of_subclasses.remove(subclass_bases)
return bases
def nothing(*args, **kwargs):
pass
class StructMeta(type, MetaClassHelper):
"""Meta class used for GI Struct based types."""
def __init__(cls, name, bases, dict_):
super(StructMeta, cls).__init__(name, bases, dict_)
# Avoid touching anything else than the base class.
g_type = cls.__info__.get_g_type()
if g_type != TYPE_INVALID and g_type.pytype is not None:
return
cls._setup_fields()
cls._setup_methods()
for method_info in cls.__info__.get_methods():
if method_info.is_constructor() and \
method_info.__name__ == 'new' and \
(not method_info.get_arguments() or
cls.__info__.get_size() == 0):
cls.__new__ = staticmethod(method_info)
# Boxed will raise an exception
# if arguments are given to __init__
cls.__init__ = nothing
break
@property
def __doc__(cls):
if cls == StructMeta:
return ''
return generate_doc_string(cls.__info__)
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