name : introspection.py # -*- coding: utf-8 -*- # slip.dbus.introspection -- access dbus introspection data # # Copyright © 2011 Red Hat, Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program 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 General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. # # Authors: # Nils Philippsen <nils@redhat.com> """Classes and functions to easily access DBus introspection data.""" from __future__ import absolute_import from xml.etree.ElementTree import ElementTree from io import StringIO from six import with_metaclass class IElemMeta(type): """Metaclass for introspection elements. Sets elemname class member automatically from class name if not set explicitly. Registers classes for their element names.""" elemnames_to_classes = {} @classmethod def clsname_to_elemname(cls, clsname): elemname = "" for c in clsname: c_lower = c.lower() if c_lower != c: if len(elemname): elemname += "_" elemname += c_lower return elemname def __new__(cls, name, bases, dct): if name == "IElem": return type.__new__(cls, name, bases, dct) if 'elemname' not in dct: if not name.startswith("IElem"): raise TypeError( "Class '%s' needs to set elemname (or be called " "'IElem...'))" % name) dct['elemname'] = IElemMeta.clsname_to_elemname(name[5:]) elemname = dct['elemname'] if elemname in IElemMeta.elemnames_to_classes: raise TypeError( "Class '%s' tries to register duplicate elemname '%s'" % (name, elemname)) kls = type.__new__(cls, name, bases, dct) IElemMeta.elemnames_to_classes[elemname] = kls return kls class IElem(with_metaclass(IElemMeta, object)): """Base class for introspection elements.""" def __new__(cls, elem, parent=None): kls = IElemMeta.elemnames_to_classes.get( elem.tag, IElemMeta.elemnames_to_classes[None]) return super(IElem, cls).__new__(kls, elem, parent) def __init__(self, elem, parent=None): self.elem = elem self.parent = parent self.child_elements = [IElem(c, parent=self) for c in elem] def __str__(self): s = "%s %r" % (self.elemname if self.elemname else "unknown:%s" % self.elem.tag, self.attrib) for c in self.child_elements: for cc in str(c).split("\n"): s += "\n %s" % (cc) return s @property def attrib(self): return self.elem.attrib class IElemUnknown(IElem): """Catch-all for unknown introspection elements.""" elemname = None class IElemNameMixin(object): """Mixin for introspection elements with names.""" @property def name(self): return self.attrib['name'] class IElemNode(IElem, IElemNameMixin): """Introspection node.""" def __init__(self, elem, parent=None): super(IElemNode, self).__init__(elem, parent) self.child_nodes = [ c for c in self.child_elements if isinstance(c, IElemNode)] class IElemInterface(IElem): """Introspection interface.""" class IElemMethod(IElem): """Introspection interface method.""" class IElemArg(IElem): """Introspection method argument.""" class IElemSignal(IElem, IElemNameMixin): """Introspection interface signal.""" def introspect(string_or_file): tree = ElementTree() # assume string if read() method doesn't exist, works for string, unicode, # dbus.String if not hasattr(string_or_file, "read"): string_or_file = StringIO(string_or_file) xml_root = tree.parse(string_or_file) elem_root = IElem(xml_root) return elem_root