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Diffstat (limited to 'src/zope/interface/adapter.py')
| -rw-r--r-- | src/zope/interface/adapter.py | 692 |
1 files changed, 692 insertions, 0 deletions
diff --git a/src/zope/interface/adapter.py b/src/zope/interface/adapter.py new file mode 100644 index 0000000..2ad145b --- /dev/null +++ b/src/zope/interface/adapter.py @@ -0,0 +1,692 @@ +############################################################################## +# +# Copyright (c) 2004 Zope Foundation and Contributors. +# All Rights Reserved. +# +# This software is subject to the provisions of the Zope Public License, +# Version 2.0 (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. +# +############################################################################## +"""Adapter management +""" + +import weakref +from zope.interface import providedBy, Interface, ro + +_marker = object +class BaseAdapterRegistry(object): + + # List of methods copied from lookup sub-objects: + _delegated = ('lookup', 'queryMultiAdapter', 'lookup1', 'queryAdapter', + 'adapter_hook', 'lookupAll', 'names', + 'subscriptions', 'subscribers') + + # All registries maintain a generation that can be used by verifying + # registries + _generation = 0 + + def __init__(self, bases=()): + + # The comments here could be improved. Possibly this bit needs + # explaining in a separate document, as the comments here can + # be quite confusing. /regebro + + # {order -> {required -> {provided -> {name -> value}}}} + # Here "order" is actually an index in a list, "required" and + # "provided" are interfaces, and "required" is really a nested + # key. So, for example: + # for order == 0 (that is, self._adapters[0]), we have: + # {provided -> {name -> value}} + # but for order == 2 (that is, self._adapters[2]), we have: + # {r1 -> {r2 -> {provided -> {name -> value}}}} + # + self._adapters = [] + + # {order -> {required -> {provided -> {name -> [value]}}}} + # where the remarks about adapters above apply + self._subscribers = [] + + # Set, with a reference count, keeping track of the interfaces + # for which we have provided components: + self._provided = {} + + # Create ``_v_lookup`` object to perform lookup. We make this a + # separate object to to make it easier to implement just the + # lookup functionality in C. This object keeps track of cache + # invalidation data in two kinds of registries. + + # Invalidating registries have caches that are invalidated + # when they or their base registies change. An invalidating + # registry can only have invalidating registries as bases. + # See LookupBasePy below for the pertinent logic. + + # Verifying registies can't rely on getting invalidation messages, + # so have to check the generations of base registries to determine + # if their cache data are current. See VerifyingBasePy below + # for the pertinent object. + self._createLookup() + + # Setting the bases causes the registries described above + # to be initialized (self._setBases -> self.changed -> + # self._v_lookup.changed). + + self.__bases__ = bases + + def _setBases(self, bases): + self.__dict__['__bases__'] = bases + self.ro = ro.ro(self) + self.changed(self) + + __bases__ = property(lambda self: self.__dict__['__bases__'], + lambda self, bases: self._setBases(bases), + ) + + def _createLookup(self): + self._v_lookup = self.LookupClass(self) + for name in self._delegated: + self.__dict__[name] = getattr(self._v_lookup, name) + + def changed(self, originally_changed): + self._generation += 1 + self._v_lookup.changed(originally_changed) + + def register(self, required, provided, name, value): + if value is None: + self.unregister(required, provided, name, value) + return + + required = tuple(map(_convert_None_to_Interface, required)) + name = _normalize_name(name) + order = len(required) + byorder = self._adapters + while len(byorder) <= order: + byorder.append({}) + components = byorder[order] + key = required + (provided,) + + for k in key: + d = components.get(k) + if d is None: + d = {} + components[k] = d + components = d + + if components.get(name) is value: + return + + components[name] = value + + n = self._provided.get(provided, 0) + 1 + self._provided[provided] = n + if n == 1: + self._v_lookup.add_extendor(provided) + + self.changed(self) + + def registered(self, required, provided, name=u''): + required = tuple(map(_convert_None_to_Interface, required)) + name = _normalize_name(name) + order = len(required) + byorder = self._adapters + if len(byorder) <= order: + return None + + components = byorder[order] + key = required + (provided,) + + for k in key: + d = components.get(k) + if d is None: + return None + components = d + + return components.get(name) + + def unregister(self, required, provided, name, value=None): + required = tuple(map(_convert_None_to_Interface, required)) + order = len(required) + byorder = self._adapters + if order >= len(byorder): + return False + components = byorder[order] + key = required + (provided,) + + # Keep track of how we got to `components`: + lookups = [] + # Keep track of how we got to `components`: + lookups = [] + for k in key: + d = components.get(k) + if d is None: + return + lookups.append((components, k)) + components = d + + old = components.get(name) + if old is None: + return + if (value is not None) and (old is not value): + return + + del components[name] + if not components: + # Clean out empty containers, since we don't want our keys + # to reference global objects (interfaces) unnecessarily. + # This is often a problem when an interface is slated for + # removal; a hold-over entry in the registry can make it + # difficult to remove such interfaces. + for comp, k in reversed(lookups): + d = comp[k] + if d: + break + else: + del comp[k] + while byorder and not byorder[-1]: + del byorder[-1] + n = self._provided[provided] - 1 + if n == 0: + del self._provided[provided] + self._v_lookup.remove_extendor(provided) + else: + self._provided[provided] = n + + self.changed(self) + + def subscribe(self, required, provided, value): + required = tuple(map(_convert_None_to_Interface, required)) + name = u'' + order = len(required) + byorder = self._subscribers + while len(byorder) <= order: + byorder.append({}) + components = byorder[order] + key = required + (provided,) + + for k in key: + d = components.get(k) + if d is None: + d = {} + components[k] = d + components = d + + components[name] = components.get(name, ()) + (value, ) + + if provided is not None: + n = self._provided.get(provided, 0) + 1 + self._provided[provided] = n + if n == 1: + self._v_lookup.add_extendor(provided) + + self.changed(self) + + def unsubscribe(self, required, provided, value=None): + required = tuple(map(_convert_None_to_Interface, required)) + order = len(required) + byorder = self._subscribers + if order >= len(byorder): + return + components = byorder[order] + key = required + (provided,) + + # Keep track of how we got to `components`: + lookups = [] + # Keep track of how we got to `components`: + lookups = [] + for k in key: + d = components.get(k) + if d is None: + return + lookups.append((components, k)) + components = d + + old = components.get(u'') + if not old: + return + + if value is None: + new = () + else: + new = tuple([v for v in old if v is not value]) + + if new == old: + return + + if new: + components[u''] = new + else: + # Instead of setting components[u''] = new, we clean out + # empty containers, since we don't want our keys to + # reference global objects (interfaces) unnecessarily. This + # is often a problem when an interface is slated for + # removal; a hold-over entry in the registry can make it + # difficult to remove such interfaces. + if u'' in components: + del components[u''] + for comp, k in reversed(lookups): + d = comp[k] + if d: + break + else: + del comp[k] + while byorder and not byorder[-1]: + del byorder[-1] + + if provided is not None: + n = self._provided[provided] + len(new) - len(old) + if n == 0: + del self._provided[provided] + self._v_lookup.remove_extendor(provided) + + self.changed(self) + + # XXX hack to fake out twisted's use of a private api. We need to get them + # to use the new registed method. + def get(self, _): + class XXXTwistedFakeOut: + selfImplied = {} + return XXXTwistedFakeOut + + +_not_in_mapping = object() +class LookupBasePy(object): + + def __init__(self): + self._cache = {} + self._mcache = {} + self._scache = {} + + def changed(self, ignored=None): + self._cache.clear() + self._mcache.clear() + self._scache.clear() + + def _getcache(self, provided, name): + cache = self._cache.get(provided) + if cache is None: + cache = {} + self._cache[provided] = cache + if name: + c = cache.get(name) + if c is None: + c = {} + cache[name] = c + cache = c + return cache + + def lookup(self, required, provided, name=u'', default=None): + cache = self._getcache(provided, name) + if len(required) == 1: + result = cache.get(required[0], _not_in_mapping) + else: + result = cache.get(tuple(required), _not_in_mapping) + + if result is _not_in_mapping: + result = self._uncached_lookup(required, provided, name) + if len(required) == 1: + cache[required[0]] = result + else: + cache[tuple(required)] = result + + if result is None: + return default + + return result + + def lookup1(self, required, provided, name=u'', default=None): + cache = self._getcache(provided, name) + result = cache.get(required, _not_in_mapping) + if result is _not_in_mapping: + return self.lookup((required, ), provided, name, default) + + if result is None: + return default + + return result + + def queryAdapter(self, object, provided, name=u'', default=None): + return self.adapter_hook(provided, object, name, default) + + def adapter_hook(self, provided, object, name=u'', default=None): + required = providedBy(object) + cache = self._getcache(provided, name) + factory = cache.get(required, _not_in_mapping) + if factory is _not_in_mapping: + factory = self.lookup((required, ), provided, name) + + if factory is not None: + result = factory(object) + if result is not None: + return result + + return default + + def lookupAll(self, required, provided): + cache = self._mcache.get(provided) + if cache is None: + cache = {} + self._mcache[provided] = cache + + required = tuple(required) + result = cache.get(required, _not_in_mapping) + if result is _not_in_mapping: + result = self._uncached_lookupAll(required, provided) + cache[required] = result + + return result + + + def subscriptions(self, required, provided): + cache = self._scache.get(provided) + if cache is None: + cache = {} + self._scache[provided] = cache + + required = tuple(required) + result = cache.get(required, _not_in_mapping) + if result is _not_in_mapping: + result = self._uncached_subscriptions(required, provided) + cache[required] = result + + return result + +LookupBase = LookupBasePy + +class VerifyingBasePy(LookupBasePy): + + def changed(self, originally_changed): + LookupBasePy.changed(self, originally_changed) + self._verify_ro = self._registry.ro[1:] + self._verify_generations = [r._generation for r in self._verify_ro] + + def _verify(self): + if ([r._generation for r in self._verify_ro] + != self._verify_generations): + self.changed(None) + + def _getcache(self, provided, name): + self._verify() + return LookupBasePy._getcache(self, provided, name) + + def lookupAll(self, required, provided): + self._verify() + return LookupBasePy.lookupAll(self, required, provided) + + def subscriptions(self, required, provided): + self._verify() + return LookupBasePy.subscriptions(self, required, provided) + +VerifyingBase = VerifyingBasePy + + +try: + import _zope_interface_coptimizations +except ImportError: + pass +else: + from _zope_interface_coptimizations import LookupBase, VerifyingBase + +class AdapterLookupBase(object): + + def __init__(self, registry): + self._registry = registry + self._required = {} + self.init_extendors() + super(AdapterLookupBase, self).__init__() + + def changed(self, ignored=None): + super(AdapterLookupBase, self).changed(None) + for r in self._required.keys(): + r = r() + if r is not None: + r.unsubscribe(self) + self._required.clear() + + + # Extendors + # --------- + + # When given an target interface for an adapter lookup, we need to consider + # adapters for interfaces that extend the target interface. This is + # what the extendors dictionary is about. It tells us all of the + # interfaces that extend an interface for which there are adapters + # registered. + + # We could separate this by order and name, thus reducing the + # number of provided interfaces to search at run time. The tradeoff, + # however, is that we have to store more information. For example, + # is the same interface is provided for multiple names and if the + # interface extends many interfaces, we'll have to keep track of + # a fair bit of information for each name. It's better to + # be space efficient here and be time efficient in the cache + # implementation. + + # TODO: add invalidation when a provided interface changes, in case + # the interface's __iro__ has changed. This is unlikely enough that + # we'll take our chances for now. + + def init_extendors(self): + self._extendors = {} + for p in self._registry._provided: + self.add_extendor(p) + + def add_extendor(self, provided): + _extendors = self._extendors + for i in provided.__iro__: + extendors = _extendors.get(i, ()) + _extendors[i] = ( + [e for e in extendors if provided.isOrExtends(e)] + + + [provided] + + + [e for e in extendors if not provided.isOrExtends(e)] + ) + + def remove_extendor(self, provided): + _extendors = self._extendors + for i in provided.__iro__: + _extendors[i] = [e for e in _extendors.get(i, ()) + if e != provided] + + + def _subscribe(self, *required): + _refs = self._required + for r in required: + ref = r.weakref() + if ref not in _refs: + r.subscribe(self) + _refs[ref] = 1 + + def _uncached_lookup(self, required, provided, name=u''): + result = None + order = len(required) + for registry in self._registry.ro: + byorder = registry._adapters + if order >= len(byorder): + continue + + extendors = registry._v_lookup._extendors.get(provided) + if not extendors: + continue + + components = byorder[order] + result = _lookup(components, required, extendors, name, 0, + order) + if result is not None: + break + + self._subscribe(*required) + + return result + + def queryMultiAdapter(self, objects, provided, name=u'', default=None): + factory = self.lookup(map(providedBy, objects), provided, name) + if factory is None: + return default + + result = factory(*objects) + if result is None: + return default + + return result + + def _uncached_lookupAll(self, required, provided): + order = len(required) + result = {} + for registry in reversed(self._registry.ro): + byorder = registry._adapters + if order >= len(byorder): + continue + extendors = registry._v_lookup._extendors.get(provided) + if not extendors: + continue + components = byorder[order] + _lookupAll(components, required, extendors, result, 0, order) + + self._subscribe(*required) + + return tuple(result.iteritems()) + + def names(self, required, provided): + return [c[0] for c in self.lookupAll(required, provided)] + + def _uncached_subscriptions(self, required, provided): + order = len(required) + result = [] + for registry in reversed(self._registry.ro): + byorder = registry._subscribers + if order >= len(byorder): + continue + + if provided is None: + extendors = (provided, ) + else: + extendors = registry._v_lookup._extendors.get(provided) + if extendors is None: + continue + + _subscriptions(byorder[order], required, extendors, u'', + result, 0, order) + + self._subscribe(*required) + + return result + + def subscribers(self, objects, provided): + subscriptions = self.subscriptions(map(providedBy, objects), provided) + if provided is None: + result = () + for subscription in subscriptions: + subscription(*objects) + else: + result = [] + for subscription in subscriptions: + subscriber = subscription(*objects) + if subscriber is not None: + result.append(subscriber) + return result + +class AdapterLookup(AdapterLookupBase, LookupBase): + pass + +class AdapterRegistry(BaseAdapterRegistry): + + LookupClass = AdapterLookup + + def __init__(self, bases=()): + # AdapterRegisties are invalidating registries, so + # we need to keep track of out invalidating subregistries. + self._v_subregistries = weakref.WeakKeyDictionary() + + super(AdapterRegistry, self).__init__(bases) + + def _addSubregistry(self, r): + self._v_subregistries[r] = 1 + + def _removeSubregistry(self, r): + if r in self._v_subregistries: + del self._v_subregistries[r] + + def _setBases(self, bases): + old = self.__dict__.get('__bases__', ()) + for r in old: + if r not in bases: + r._removeSubregistry(self) + for r in bases: + if r not in old: + r._addSubregistry(self) + + super(AdapterRegistry, self)._setBases(bases) + + def changed(self, originally_changed): + super(AdapterRegistry, self).changed(originally_changed) + + for sub in self._v_subregistries.keys(): + sub.changed(originally_changed) + + +class VerifyingAdapterLookup(AdapterLookupBase, VerifyingBase): + pass + +class VerifyingAdapterRegistry(BaseAdapterRegistry): + + LookupClass = VerifyingAdapterLookup + +def _convert_None_to_Interface(x): + if x is None: + return Interface + else: + return x + +def _normalize_name(name): + if isinstance(name, basestring): + return unicode(name) + + raise TypeError("name must be a regular or unicode string") + +def _lookup(components, specs, provided, name, i, l): + if i < l: + for spec in specs[i].__sro__: + comps = components.get(spec) + if comps: + r = _lookup(comps, specs, provided, name, i+1, l) + if r is not None: + return r + else: + for iface in provided: + comps = components.get(iface) + if comps: + r = comps.get(name) + if r is not None: + return r + + return None + +def _lookupAll(components, specs, provided, result, i, l): + if i < l: + for spec in reversed(specs[i].__sro__): + comps = components.get(spec) + if comps: + _lookupAll(comps, specs, provided, result, i+1, l) + else: + for iface in reversed(provided): + comps = components.get(iface) + if comps: + result.update(comps) + +def _subscriptions(components, specs, provided, name, result, i, l): + if i < l: + for spec in reversed(specs[i].__sro__): + comps = components.get(spec) + if comps: + _subscriptions(comps, specs, provided, name, result, i+1, l) + else: + for iface in reversed(provided): + comps = components.get(iface) + if comps: + comps = comps.get(name) + if comps: + result.extend(comps) |