From 0cb26ef3ec68739a888f4295103210d301c2f9a8 Mon Sep 17 00:00:00 2001 From: Jason Gerard DeRose Date: Sun, 20 Jul 2008 07:09:28 +0000 Subject: [PATCH] 15: Added ipalib.base2 module where I'm experimenting with a 3rd approach that is a hybrid of the first two: a decoupled late binding OO strategy --- ipalib/base2.py | 102 ++++++++++++++++++++++++++ ipalib/exceptions.py | 4 ++ ipalib/tests/test_base2.py | 142 +++++++++++++++++++++++++++++++++++++ 3 files changed, 248 insertions(+) create mode 100644 ipalib/base2.py create mode 100644 ipalib/tests/test_base2.py diff --git a/ipalib/base2.py b/ipalib/base2.py new file mode 100644 index 000000000..fa5536bd0 --- /dev/null +++ b/ipalib/base2.py @@ -0,0 +1,102 @@ +# Authors: +# Jason Gerard DeRose +# +# Copyright (C) 2008 Red Hat +# see file 'COPYING' for use and warranty information +# +# 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; version 2 only +# +# 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, write to the Free Software +# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + +""" +Base classes for plug-in architecture and generative API. +""" + +import inspect +import exceptions +from base import NameSpace + + +class Named(object): + def __get_name(self): + return self.__class__.__name__ + name = property(__get_name) + + +class WithObj(Named): + _obj = None + __obj = None + + def __get_obj(self): + return self.__obj + def __set_obj(self, obj): + if self.__obj is not None: + raise exceptions.TwiceSetError(self.__class__.__name__, 'obj') + assert isinstance(obj, Named) + assert isinstance(self._obj, str) + assert obj.name == self._obj + self.__obj = obj + assert self.obj is obj + obj = property(__get_obj, __set_obj) + + +class Command(WithObj): + pass + +class Property(WithObj): + pass + +class Object(Named): + pass + + +class Registrar(object): + __object = None + __commands = None + __properties = None + + def __init__(self): + self.__tmp_objects = {} + self.__tmp_commands = {} + self.__tmp_properties = {} + + def __get_objects(self): + return self.__objects + objects = property(__get_objects) + + def __get_commands(self): + return self.__commands + commands = property(__get_commands) + + def __get_target(self, i): + if isinstance(i, Object): + return (self.__tmp_objects, i.name) + if isinstance(i, Command): + return (self.__tmp_commands, i.name) + assert isinstance(i, Property) + + + def register(self, cls): + assert inspect.isclass(cls) + assert issubclass(cls, Named) + i = cls() + (target, key) = self.__get_target(i) + target[key] = i + + def finalize(self): + for cmd in self.__tmp_commands.values(): + if cmd._obj is None: + continue + obj = self.__tmp_objects[cmd._obj] + cmd.obj = obj + self.__objects = NameSpace(self.__tmp_objects) + self.__commands = NameSpace(self.__tmp_commands) diff --git a/ipalib/exceptions.py b/ipalib/exceptions.py index 4584c1eea..76c7da8c2 100644 --- a/ipalib/exceptions.py +++ b/ipalib/exceptions.py @@ -63,3 +63,7 @@ class RegistrationError(IPAError): class PrefixError(IPAError): msg = 'class name %r must start with %r' + + +class TwiceSetError(IPAError): + msg = '%s.%s cannot be set twice' diff --git a/ipalib/tests/test_base2.py b/ipalib/tests/test_base2.py new file mode 100644 index 000000000..cdf96bdb3 --- /dev/null +++ b/ipalib/tests/test_base2.py @@ -0,0 +1,142 @@ +# Authors: +# Jason Gerard DeRose +# +# Copyright (C) 2008 Red Hat +# see file 'COPYING' for use and warranty information +# +# 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; version 2 only +# +# 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, write to the Free Software +# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + +""" +Unit tests for `ipalib.base` module. +""" + +from ipalib import base2 as base +from ipalib import exceptions + + +def read_only(obj, name): + """ + Check that a given property is read-only. + Returns the value of the property. + """ + assert isinstance(obj, object) + assert hasattr(obj, name) + raised = False + try: + setattr(obj, name, 'some new obj') + except AttributeError: + raised = True + assert raised + return getattr(obj, name) + + +class ClassChecker(object): + cls = None # Override this is subclasses + + def new(self, *args, **kw): + return self.cls(*args, **kw) + + def args(self): + return [] + + def kw(self): + return {} + + def std(self): + return self.new(*self.args(), **self.kw()) + + + +def test_Named(): + class named_class(base.Named): + pass + + i = named_class() + assert i.name == 'named_class' + + +def test_WithObj(): + class some_object(base.Named): + pass + + class another_object(base.Named): + pass + + class some_command(base.WithObj): + _obj = 'some_object' + + obj = some_object() + cmd = some_command() + + # Test that it can be set: + assert cmd.obj is None + cmd.obj = obj + assert cmd.obj is obj + + # Test that it cannot be set twice: + raised = False + try: + cmd.obj = obj + except exceptions.TwiceSetError: + raised = True + assert raised + + # Test that it can't be set with the wrong name: + obj = another_object() + cmd = some_command() + raised = False + try: + cmd.obj = obj + except AssertionError: + raised = True + assert raised + + +def test_Registar(): + class adduser(base.Command): + _obj = 'user' + class moduser(base.Command): + _obj = 'user' + class deluser(base.Command): + _obj = 'user' + class finduser(base.Command): + _obj = 'user' + class kinit(base.Command): + pass + class user(base.Object): + pass + class group(base.Object): + pass + + r = base.Registrar() + r.register(adduser) + r.register(moduser) + r.register(deluser) + r.register(finduser) + r.register(kinit) + r.register(user) + r.register(group) + + r.finalize() + assert len(r.commands) == 5 + assert len(r.objects) == 2 + + obj = r.objects.user + assert type(obj) is user + for name in ['adduser', 'moduser', 'deluser', 'finduser']: + cmd = r.commands[name] + assert type(cmd) is locals()[name] + assert cmd.obj is obj + + assert r.commands.kinit.obj is None