Current File : //lib/python3/dist-packages/zope/component/hooks.py
##############################################################################
#
# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Hooks for getting and setting a site in the thread global namespace.
"""
__docformat__ = 'restructuredtext'
import contextlib
import threading
try:
from zope.security.proxy import removeSecurityProxy
except ImportError: #pragma NO COVER
def removeSecurityProxy(x):
return x
from zope.component.globalregistry import getGlobalSiteManager
from zope.component.interfaces import ComponentLookupError
from zope.component.interfaces import IComponentLookup
class read_property(object):
"""Descriptor for property-like computed attributes.
Unlike the standard 'property', this descriptor allows assigning a
value to the instance, shadowing the property getter function.
"""
def __init__(self, func):
self.func = func
def __get__(self, inst, cls):
if inst is None:
return self
return self.func(inst)
class SiteInfo(threading.local):
site = None
sm = getGlobalSiteManager()
@read_property
def adapter_hook(self):
adapter_hook = self.sm.adapters.adapter_hook
self.adapter_hook = adapter_hook
return adapter_hook
siteinfo = SiteInfo()
def setSite(site=None):
if site is None:
sm = getGlobalSiteManager()
else:
# We remove the security proxy because there's no way for
# untrusted code to get at it without it being proxied again.
# We should really look look at this again though, especially
# once site managers do less. There's probably no good reason why
# they can't be proxied. Well, except maybe for performance.
site = removeSecurityProxy(site)
# The getSiteManager method is defined by IPossibleSite.
sm = site.getSiteManager()
siteinfo.site = site
siteinfo.sm = sm
try:
del siteinfo.adapter_hook
except AttributeError:
pass
def getSite():
return siteinfo.site
@contextlib.contextmanager
def site(site):
old_site = getSite()
setSite(site)
try:
yield
finally:
setSite(old_site)
def getSiteManager(context=None):
"""A special hook for getting the site manager.
Here we take the currently set site into account to find the appropriate
site manager.
"""
if context is None:
return siteinfo.sm
# We remove the security proxy because there's no way for
# untrusted code to get at it without it being proxied again.
# We should really look look at this again though, especially
# once site managers do less. There's probably no good reason why
# they can't be proxied. Well, except maybe for performance.
sm = IComponentLookup(
context, getGlobalSiteManager())
sm = removeSecurityProxy(sm)
return sm
def adapter_hook(interface, object, name='', default=None):
try:
return siteinfo.adapter_hook(interface, object, name, default)
except ComponentLookupError:
return default
def setHooks():
from zope.component import _api
_api.adapter_hook.sethook(adapter_hook)
_api.getSiteManager.sethook(getSiteManager)
def resetHooks():
# Reset hookable functions to original implementation.
from zope.component import _api
_api.adapter_hook.reset()
_api.getSiteManager.reset()
# be sure the old adapter hook isn't cached, since
# it is derived from the SiteManager
try:
del siteinfo.adapter_hook
except AttributeError:
pass
# Clear the site thread global
clearSite = setSite
try:
from zope.testing.cleanup import addCleanUp
except ImportError: #pragma NO COVER
pass
else:
addCleanUp(resetHooks)
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