[Cvsshell-devel] CVS: cvsshell/src oo_tools.py,NONE,1.1

[Stefan H. <ste...@us...>]

Update of /cvsroot/cvsshell/cvsshell/src
In directory usw-pr-cvs1:/tmp/cvs-serv32725

Added Files:
	oo_tools.py 
Log Message:
initial checkin


--- NEW FILE: oo_tools.py ---
###############################################################################
# This file is part of CvsShell  
# 
# CvsShell 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.
# 
# CvsShell 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 CvsShell; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
# 
# Copyright 2002 by Stefan Heimann
# Website: http://cvsshell.sourceforge.net/
###############################################################################


# This class is not thread-safe! Prior to python 2.2 it is not possible
# to write something like:
# def foo():
#     x = 5
#     def bar():
#         print x
#     bar()
# and so all communication between the inner and the outer function
# has to be done with global variables.
#
# To make it thread-safe, one must lock all access-points of the variable
# GetSetProvider.__storage.

AccessError = 'AccessError'

class GetSetProvider:
    """Classes which are derived from GetSetProvider have implicit
    get/set methods for all their variables.
    """

    def __init__(self):
        self.__readonly = []
        self.__private = []
        
    def __getattr__(self, name):
        if len(name) > 3:
            pre, attr = name[:3], name[3].lower() + name[4:]
            if attr[0] == '_':
                self.__raiseAccessError(attr, 'private')
            if pre == 'get':
                if attr in self.__private:
                    self.__raiseAccessError(attr, 'private')
                GetSetProvider.__storage = eval('self.' + attr)
                return lambda : GetSetProvider.__storage
            if pre == 'set':
                if attr in self.__private:
                    self.__raiseAccessError(attr, 'private')
                elif attr in self.__readonly:
                    self.__raiseAccessError(attr, 'readonly')
                GetSetProvider.__storage = (self.__dict__, attr)
                def __set(val):
                    dict, name = GetSetProvider.__storage
                    dict[name] = val
                return __set
        raise AttributeError, "class %s has no attribute '%s'" % \
              (self.__class__.__name__, name)

    def _GetSetProvider__raiseAccessError(self, attr, access):
        raise AccessError, \
              'attribute %s in class %s has %s access' % \
              (attr, self.__class__.__name__, access)

    def _setReadonly_(self, name):
        self.__readonly.append(name)

    def _setPrivate_(self, name):
        self.__private.append(name)



##############################
# TestCases
##############################
if __name__ == '__main__':

    import unittest

    class Test(GetSetProvider):
        def __init__(self, name):
            GetSetProvider.__init__(self)
            self.name = name
            self.private = None
            self._setPrivate_('private')
            self.readonly = 'readonly'
            self._setReadonly_('readonly')
            
    class GetSetProviderTestCase(unittest.TestCase):
        def setUp(self):
            self.t = Test('Stefan')
        def tearDown(self):
            del self.t
        def testGet(self):
            self.assertEqual(self.t.getName(), 'Stefan')
            try:
                self.t.getAge()
                self.fail('should raise exception here.')
            except AttributeError: pass
        def testSet(self):
            self.t.setName('Heimann')
            self.assertEqual(self.t.getName(), 'Heimann')
            self.t.setAge(23)
            self.assertEqual(self.t.getAge(), 23)
        def testAccess(self):
            self.assertEqual(self.t.getReadonly(), 'readonly')
            try:
                self.t.setReadonly(None)
                fail('should raise exception here.')
            except AccessError: pass
            try:
                self.t.getPrivate()
                fail('should raise exception here.')
            except AccessError: pass
            try:
                self.t.setPrivate(None)
                fail('should raise exception here.')
            except AccessError: pass
                

    unittest.main()