[Zope-Checkins] CVS: Zope2 - SafeMapping.py:1.1

[evan@serenade.digicool.com]

Update of /cvs-repository/Zope2/lib/python/RestrictedPython
In directory serenade.digicool.com:/home/evan/Zope/trunk/lib/python/RestrictedPython

Added Files:
	SafeMapping.py 
Log Message:
Add SafeMapping class, for use when mappings (or MultiMappings) need to be exposed to restricted code.



--- Added File SafeMapping.py in package Zope2 ---
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__doc__='''Read-only Mapping class based on MultiMapping

$Id: SafeMapping.py,v 1.1 2001/05/08 18:15:36 evan Exp $'''
__version__='$Revision: 1.1 $'[11:-2]

from MultiMapping import MultiMapping

_marker = []

class SafeMapping(MultiMapping):
    '''Mapping with security declarations and limited method exposure.

    Since it subclasses MultiMapping, this class can be used to wrap
    one or more mapping objects.  Restricted Python code will not be
    able to mutate the SafeMapping or the wrapped mappings, but will be
    able to read any value.
    '''
    __allow_access_to_unprotected_subobjects__ = 1
    push = pop = None
    def _push(self, ob):
        MultiMapping.push(self, ob)
    def _pop(self, *args):
        if args:
            return apply(MultiMapping.pop, (self,) + args)
        else:
            return MultiMapping.pop(self)
    def has_get(self, key):
        v = self.get(key, _marker)
        if v is _marker:
            return 0, None
        else:
            return 1, v