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'''This module implements a mix-in for traversable objects.

$Id: Traversable.py,v 1.8 2001/05/21 19:47:28 evan Exp $'''
__version__='$Revision: 1.8 $'[11:-2]


import Acquisition
from AccessControl import getSecurityManager
from string import split, join
from urllib import quote

_marker=[]
StringType=type('')

class Traversable:

    absolute_url__roles__=None # Public
    def absolute_url(self, relative=0):
        try:
            req = self.REQUEST
        except AttributeError:
            req = {}
        rpp = req.get('VirtualRootPhysicalPath', ('',))
        spp = self.getPhysicalPath()
        i = 0
        for name in rpp[:len(spp)]:
            if spp[i] == name:
                i = i + 1
            else:
                break
        path = map(quote, spp[i:])
        if relative:
            # This is useful for physical path relative to a VirtualRoot
            return join(path, '/')
        return join([req['SERVER_URL']] + req._script + path, '/')

    getPhysicalRoot=Acquisition.Acquired
    getPhysicalRoot__roles__=() # Private

    getPhysicalPath__roles__=None # Public
    def getPhysicalPath(self):
        '''Returns a path (an immutable sequence of strings)
        that can be used to access this object again
        later, for example in a copy/paste operation.  getPhysicalRoot()
        and getPhysicalPath() are designed to operate together.
        '''
        path = (self.getId(),)
        
        p = getattr(self,'aq_inner', None)
        if p is not None: 
            path = p.aq_parent.getPhysicalPath() + path

        return path

    unrestrictedTraverse__roles__=() # Private
    def unrestrictedTraverse(self, path, default=_marker, restricted=0):

        if not path: return self

        get=getattr
        N=None
        M=_marker

        if type(path) is StringType: path = split(path,'/')
        else: path=list(path)

        REQUEST={'TraversalRequestNameStack': path}
        path.reverse()
        pop=path.pop

        if len(path) > 1 and not path[0]:
            # Remove trailing slash
            path.pop(0)

        if restricted: securityManager=getSecurityManager()
        else: securityManager=None

        if not path[-1]:
            # If the path starts with an empty string, go to the root first.
            pop()
            self=self.getPhysicalRoot()
            if (restricted and not securityManager.validateValue(self)):
                raise 'Unauthorized', name
                    
        try:
            object = self
            while path:
                name=pop()

                if name[0] == '_':
                    # Never allowed in a URL.
                    raise 'NotFound', name

                if name=='..':
                    o=getattr(object, 'aq_parent', M)
                    if o is not M:
                        if (restricted and not securityManager.validate(
                            object, object,name, o)):
                            raise 'Unauthorized', name
                        object=o
                        continue

                t=get(object, '__bobo_traverse__', N)
                if t is not N:
                    o=t(REQUEST, name)
                    
                    # Note we pass no container, because we have no
                    # way of knowing what it is
                    if (restricted and not securityManager.validate(
                        object, None, name, o)):
                        raise 'Unauthorized', name
                      
                else:
                    o=get(object, name, M)
                    if o is not M:
                        if restricted:
                            # waaaa
                            if hasattr(get(object,'aq_base',object), name):
                                # value wasn't acquired
                                if not securityManager.validate(
                                    object, object, name, o):
                                    raise 'Unauthorized', name
                            else:
                                if not securityManager.validate(
                                    object, None, name, o):
                                    raise 'Unauthorized', name
                        
                    else:
                        o=object[name]
                        if (restricted and not securityManager.validate(
                            object, object, None, o)):
                            raise 'Unauthorized', name

                object=o

            return object

        except:
            if default==_marker: raise
            return default

    restrictedTraverse__roles__=None # Public
    def restrictedTraverse(self, path, default=_marker):
        return self.unrestrictedTraverse(path, default, restricted=1)
