有时我需要调用一个只存在于C语言中的gtk/gobject函数,但返回一个具有Python包装器的对象。 以前我使用了一个基于ctypes的解决方案,效果很好:http://faq.pygtk.org/index.py?req=show&file=faq23.041.htp。现在我已经从PyGtk(“import gtk”)转换到GObject-introspection(“from gi.repository import Gtk”),我应该使用什么替代方法?
_PyGObject_API
接口已经发生了变化。我需要删除register_sinkfunc
函数。以下是可以使用的代码:
from gi.repository import Gio, GLib
import gi
import ctypes
class _PyGObject_Functions(ctypes.Structure):
_fields_ = [
('register_class',
ctypes.PYFUNCTYPE(ctypes.c_void_p, ctypes.c_char_p,
ctypes.c_int, ctypes.py_object,
ctypes.py_object)),
('register_wrapper',
ctypes.PYFUNCTYPE(ctypes.c_void_p, ctypes.py_object)),
('lookup_class',
ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_int)),
('newgobj',
ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)),
]
class PyGObjectCPAI(object):
def __init__(self):
PyCObject_AsVoidPtr = ctypes.pythonapi.PyCObject_AsVoidPtr
PyCObject_AsVoidPtr.restype = ctypes.c_void_p
PyCObject_AsVoidPtr.argtypes = [ctypes.py_object]
addr = PyCObject_AsVoidPtr(ctypes.py_object(
gi._gobject._PyGObject_API))
self._api = _PyGObject_Functions.from_address(addr)
def pygobject_new(self, addr):
return self._api.newgobj(addr)
capi = PyGObjectCPAI()
obj = capi.pygobject_new(pointer)
从(g)对象获取一个指针的方法:
pointer = hash(obj)
我必须提醒的是,对于我的实际问题来说这并没有帮助我解决。我正在尝试与dconf接口,但是dconf返回的值是GVariant类型,它不继承自GObject。看起来PyGI/GObject不幸地没有暴露将C(* GVariant)转换为Python GLib.Variant所需的函数。我想这是那种时候,你必须放弃初始的方法,尝试一些不同的方法。
CObject
在Python 2.7和3.1中已被弃用,并且自3.2开始删除,我调整了代码以使用Capsule
(自2.7以来可用)。import ctypes, gi
class _PyGObject_Functions(ctypes.Structure):
_fields_ = [
('register_class',
ctypes.PYFUNCTYPE(ctypes.c_void_p, ctypes.c_char_p,
ctypes.c_int, ctypes.py_object, ctypes.py_object)),
('register_wrapper',
ctypes.PYFUNCTYPE(ctypes.c_void_p, ctypes.py_object)),
('lookup_class',
ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_int)),
('newgobj',
ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)),
]
class PyGObjectCAPI(object):
def __init__(self):
self._as_void_ptr.restype = ctypes.c_void_p
self._as_void_ptr.argtypes = [ctypes.py_object]
addr = self._as_void_ptr(ctypes.py_object(
gi._gobject._PyGObject_API))
self._api = _PyGObject_Functions.from_address(addr)
@staticmethod
def _as_void_ptr(obj):
name = ctypes.pythonapi.PyCapsule_GetName(obj)
return ctypes.pythonapi.PyCapsule_GetPointer(obj, name)
def pygobject_new(self, addr):
return self._api.newgobj(addr)
capi = PyGObjectCAPI()
我还将其重命名为PyGobjectC API--不确定CPAI代表什么,但这样对我来说更有意义。
自AlliedEnvy的更新以来,PyGOject API已发生变化。
import gi
import ctypes
from ctypes import pythonapi
class _PyGObject_Functions(ctypes.Structure):
_fields_ = [
('pygobject_register_class',
ctypes.PYFUNCTYPE(ctypes.c_void_p)),
('pygobject_register_wrapper',
ctypes.PYFUNCTYPE(ctypes.c_void_p)),
('pygobject_lookup_class',
ctypes.PYFUNCTYPE(ctypes.c_void_p)),
('pygobject_new',
ctypes.PYFUNCTYPE(ctypes.py_object, ctypes.c_void_p)),
]
class PyGObjectCAPI(object):
def __init__(self):
addr = self._as_void_ptr(gi._gobject._PyGObject_API)
self._api = _PyGObject_Functions.from_address(addr)
@classmethod
def _capsule_name(cls, capsule):
pythonapi.PyCapsule_GetName.restype = ctypes.c_char_p
pythonapi.PyCapsule_GetName.argtypes = [ctypes.py_object]
return pythonapi.PyCapsule_GetName(capsule)
@classmethod
def _as_void_ptr(cls, capsule):
name = cls._capsule_name(capsule)
pythonapi.PyCapsule_GetPointer.restype = ctypes.c_void_p
pythonapi.PyCapsule_GetPointer.argtypes = [
ctypes.py_object, ctypes.c_char_p]
return pythonapi.PyCapsule_GetPointer(capsule, name)
def to_object(self, addr):
return self._api.pygobject_new(addr)
capi = PyGObjectCAPI()
.typelib
,.gir
)的出现,无论使用哪种语言,相同的API都应该可用。也就是说,如果您正在使用不在API中的C函数,则可能正在使用仅供内部使用的函数。