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# -*- test-case-name: nevow.test.test_context -*-
# Copyright (c) 2004 Divmod.
# See LICENSE for details.
from __future__ import generators
import warnings
from nevow import stan
from nevow.inevow import IData, IRequest
from nevow.stan import Unset
from nevow.util import qual
from zope.interface import providedBy
# TTT: Move to web2.context
def megaGetInterfaces(adapter):
return [qual(x) for x in providedBy(adapter)]
dataqual = qual(IData)
class WebContext(object):
_remembrances = None
tag = None
_slotData = None
parent = None
locateHook = None
# XXX: can we get rid of these somehow?
isAttrib = property(lambda self: False)
inURL = property(lambda self: False)
inJS = property(lambda self: False)
inJSSingleQuoteString = property(lambda self: False)
precompile = property(lambda self: False)
def arg(self, get, default=None):
"""Placeholder until I can find Jerub's implementation of this
Return a single named argument from the request arguments
"""
req = self.locate(IRequest)
return req.args.get(get, [default])[0]
def __init__(self, parent=None, tag=None, remembrances=None):
self.tag = tag
sd = getattr(tag, 'slotData', None)
if sd is not None:
self._slotData = sd
self.parent = parent
self._remembrances = remembrances
def remember(self, adapter, interface=None):
"""Remember an object that implements some interfaces.
Later, calls to .locate which are passed an interface implemented
by this object will return this object.
If the 'interface' argument is supplied, this object will only
be remembered for this interface, and not any of
the other interfaces it implements.
"""
if interface is None:
interfaceList = megaGetInterfaces(adapter)
if not interfaceList:
interfaceList = [dataqual]
else:
interfaceList = [qual(interface)]
if self._remembrances is None:
self._remembrances = {}
for interface in interfaceList:
self._remembrances[interface] = adapter
return self
def locate(self, interface, depth=1, _default=object()):
"""Locate an object which implements a given interface.
Objects will be searched through the context stack top
down.
"""
key = qual(interface)
currentContext = self
while True:
if depth < 0:
full = []
while True:
try:
full.append(self.locate(interface, len(full)+1))
except KeyError:
break
#print "full", full, depth
if full:
return full[depth]
return None
_remembrances = currentContext._remembrances
if _remembrances is not None:
rememberedValue = _remembrances.get(key, _default)
if rememberedValue is not _default:
depth -= 1
if not depth:
return rememberedValue
# Hook for FactoryContext and other implementations of complex locating
locateHook = currentContext.locateHook
if locateHook is not None:
result = locateHook(interface)
if result is not None:
currentContext.remember(result, interface)
return result
contextParent = currentContext.parent
if contextParent is None:
raise KeyError, "Interface %s was not remembered." % key
currentContext = contextParent
def chain(self, context):
"""For nevow machinery use only.
Go to the top of this context's context chain, and make
the given context the parent, thus continuing the chain
into the given context's chain.
"""
top = self
while top.parent is not None:
if top.parent.tag is None:
## If top.parent.tag is None, that means this context (top)
## is just a marker. We want to insert the current context
## (context) as the parent of this context (top) to chain properly.
break
top = top.parent
if top is context: # this context is already in the chain; don't create a cycle
return
top.parent = context
def fillSlots(self, name, stan):
"""Set 'stan' as the stan tree to replace all slots with name 'name'.
"""
if self._slotData is None:
self._slotData = {}
self._slotData[name] = stan
def locateSlotData(self, name):
"""For use by nevow machinery only, or for some fancy cases.
Find previously remembered slot filler data.
For use by flatstan.SlotRenderer"""
currentContext = self
while True:
if currentContext._slotData:
data = currentContext._slotData.get(name, Unset)
if data is not Unset:
return data
if currentContext.parent is None:
raise KeyError, "Slot named '%s' was not filled." % name
currentContext = currentContext.parent
def clone(self, deep=True, cloneTags=True):
## don't clone the tags of parent contexts. I *hope* code won't be
## trying to modify parent tags so this should not be necessary. We
## used to also clone parent contexts, but that is insanely expensive.
## The only code that actually required that behavior is
## ContextSerializer, which is the only caller of context.chain. So
## instead of doing the clone here, now we do it there.
if self.parent is not None:
if deep:
parent = self.parent.clone(cloneTags=False)
else:
parent = self.parent
else:
parent = None
if cloneTags:
tag = self.tag.clone(deep=deep)
else:
tag = self.tag
if self._remembrances is not None:
remembrances = self._remembrances.copy()
else:
remembrances = None
return type(self)(
parent=parent,
tag=tag,
remembrances=remembrances,
)
def __conform__(self, interface):
"""Support IFoo(ctx) syntax.
"""
try:
return self.locate(interface)
except KeyError:
return None
def __repr__(self):
rstr = ''
if self._remembrances:
rstr = ', remembrances=%r' % self._remembrances
return "%s(tag=%r%s)" % (self.__class__.__name__, self.tag, rstr)
class FactoryContext(WebContext):
"""A context which allows adapters to be registered against it so that an object
can be lazily created and returned at render time. When ctx.locate is called
with an interface for which an adapter is registered, that adapter will be used
and the result returned.
"""
inLocate = 0
def locateHook(self, interface):
## Prevent infinite recursion from interface(self) calling self.getComponent calling self.locate
self.inLocate += 1
adapter = interface(self, None)
self.inLocate -= 1
return adapter
def __conform__(self, interface):
if self.inLocate:
return None
return WebContext.__conform__(self, interface)
class SiteContext(FactoryContext):
"""A SiteContext is created and installed on a NevowSite upon initialization.
It will always be used as the root context, and can be used as a place to remember
things sitewide.
"""
pass
class RequestContext(FactoryContext):
"""A RequestContext has adapters for the following interfaces:
ISession
IFormDefaults
IFormErrors
IHand
IStatusMessage
"""
pass
def getRequestContext(self):
top = self.parent
while not isinstance(top, RequestContext):
top = top.parent
return top
class PageContext(FactoryContext):
"""A PageContext has adapters for the following interfaces:
IRenderer
IRendererFactory
IData
"""
def __init__(self, *args, **kw):
FactoryContext.__init__(self, *args, **kw)
if self.tag is not None and hasattr(self.tag, 'toremember'):
for i in self.tag.toremember:
self.remember(*i)
# TTT: To stay here.
NodeNotFound = stan.NodeNotFound # XXX: DeprecationWarning?
TooManyNodes = stan.TooManyNodes # XXX: DeprecationWarning?
class WovenContext(WebContext):
key = None
isAttrib = False
inURL = False
precompile = False
inJS = False
inJSSingleQuoteString = False
def __init__(self, parent=None, tag=None, precompile=None, remembrances=None, key=None, isAttrib=None, inURL=None, inJS=None, inJSSingleQuoteString=None):
WebContext.__init__(self, parent, tag, remembrances)
if self.parent:
self.precompile = parent.precompile
self.isAttrib = parent.isAttrib
self.inURL = parent.inURL
self.inJS = parent.inJS
self.inJSSingleQuoteString = parent.inJSSingleQuoteString
if self.tag is not None:
if self.tag.remember is not Unset:
self.remember(tag.remember)
if key is None:
key = self.tag.key
if key is not None and key is not Unset:
if self.parent is not None and getattr(self.parent, 'key', None):
self.key = '.'.join((self.parent.key, key))
else:
self.key = key
#print "KEY", `self.key`
else:
## Bubble the value down to the bottom so it's always immediately accessible
if self.parent is not None:
self.key = getattr(self.parent, 'key', '')
if precompile is not None: self.precompile = precompile
if isAttrib is not None: self.isAttrib = isAttrib
if inURL is not None: self.inURL = inURL
if inJS is not None: self.inJS = inJS
if inJSSingleQuoteString is not None: self.inJSSingleQuoteString = inJSSingleQuoteString
def __repr__(self):
rstr = ''
if self._remembrances:
rstr = ', remembrances=%r' % self._remembrances
attribstr=''
if self.isAttrib:
attribstr=", isAttrib=True"
urlStr = ''
if self.inURL:
urlStr = ', inURL=True'
return "%s(tag=%r%s%s%s)" % (self.__class__.__name__, self.tag, rstr,attribstr,urlStr)
def patternGenerator(self, pattern, default=None):
warnings.warn("use Tag.patternGenerator instead", DeprecationWarning, stacklevel=2)
return self.tag.patternGenerator(pattern, default)
def allPatterns(self, pattern):
warnings.warn("use Tag.allPatterns instead", DeprecationWarning, stacklevel=2)
return self.tag.allPatterns(pattern)
def onePattern(self, pattern):
warnings.warn("use Tag.onePattern instead", DeprecationWarning, stacklevel=2)
return self.tag.onePattern(pattern)
def clone(self, deep=True, cloneTags=True):
cloned = WebContext.clone(self, deep, cloneTags)
cloned.isAttrib = self.isAttrib
cloned.inURL = self.inURL
return cloned
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