# This Source Code Form is subject to the terms of the Mozilla Public # License, v. 2.0. If a copy of the MPL was not distributed with this file, # You can obtain one at http://mozilla.org/MPL/2.0/. from WebIDL import IDLImplementsStatement import os from collections import defaultdict autogenerated_comment = "/* THIS FILE IS AUTOGENERATED - DO NOT EDIT */\n" class DescriptorProvider: """ A way of getting descriptors for interface names. Subclasses must have a getDescriptor method callable with the interface name only. """ def __init__(self): pass class Configuration(DescriptorProvider): """ Represents global configuration state based on IDL parse data and the configuration file. """ def __init__(self, filename, parseData, generatedEvents=[]): DescriptorProvider.__init__(self) # Read the configuration file. glbl = {} execfile(filename, glbl) config = glbl['DOMInterfaces'] # Build descriptors for all the interfaces we have in the parse data. # This allows callers to specify a subset of interfaces by filtering # |parseData|. self.descriptors = [] self.interfaces = {} self.descriptorsByName = {} self.optimizedOutDescriptorNames = set() self.generatedEvents = generatedEvents self.maxProtoChainLength = 0 for thing in parseData: if isinstance(thing, IDLImplementsStatement): # Our build system doesn't support dep build involving # addition/removal of "implements" statements that appear in a # different .webidl file than their LHS interface. Make sure we # don't have any of those. # # But whitelist a RHS that is LegacyQueryInterface, # since people shouldn't be adding any of those. if (thing.implementor.filename() != thing.filename() and thing.implementee.identifier.name != "LegacyQueryInterface"): raise TypeError( "The binding build system doesn't really support " "'implements' statements which don't appear in the " "file in which the left-hand side of the statement is " "defined. Don't do this unless your right-hand side " "is LegacyQueryInterface.\n" "%s\n" "%s" % (thing.location, thing.implementor.location)) assert not thing.isType() if not thing.isInterface() and not thing.isNamespace(): continue iface = thing self.interfaces[iface.identifier.name] = iface if iface.identifier.name not in config: # Completely skip consequential interfaces with no descriptor # if they have no interface object because chances are we # don't need to do anything interesting with them. if iface.isConsequential() and not iface.hasInterfaceObject(): self.optimizedOutDescriptorNames.add(iface.identifier.name) continue entry = {} else: entry = config[iface.identifier.name] assert not isinstance(entry, list) desc = Descriptor(self, iface, entry) self.descriptors.append(desc) # Setting up descriptorsByName while iterating through interfaces # means we can get the nativeType of iterable interfaces without # having to do multiple loops. assert desc.interface.identifier.name not in self.descriptorsByName self.descriptorsByName[desc.interface.identifier.name] = desc # Keep the descriptor list sorted for determinism. self.descriptors.sort(lambda x, y: cmp(x.name, y.name)) self.descriptorsByFile = {} for d in self.descriptors: self.descriptorsByFile.setdefault(d.interface.filename(), []).append(d) self.enums = [e for e in parseData if e.isEnum()] self.dictionaries = [d for d in parseData if d.isDictionary()] self.callbacks = [c for c in parseData if c.isCallback() and not c.isInterface()] # Dictionary mapping from a union type name to a set of filenames where # union types with that name are used. self.filenamesPerUnion = defaultdict(set) # Dictionary mapping from a filename to a list of types for # the union types used in that file. If a union type is used # in multiple files then it will be added to the list for the # None key. Note that the list contains a type for every use # of a union type, so there can be multiple entries with union # types that have the same name. self.unionsPerFilename = defaultdict(list) for (t, _) in getAllTypes(self.descriptors, self.dictionaries, self.callbacks): while True: if t.isMozMap(): t = t.inner elif t.unroll() != t: t = t.unroll() elif t.isPromise(): t = t.promiseInnerType() else: break if t.isUnion(): filenamesForUnion = self.filenamesPerUnion[t.name] if t.filename() not in filenamesForUnion: # We have a to be a bit careful: some of our built-in # typedefs are for unions, and those unions end up with # "<unknown>" as the filename. If that happens, we don't # want to try associating this union with one particular # filename, since there isn't one to associate it with, # really. if t.filename() == "<unknown>": uniqueFilenameForUnion = None elif len(filenamesForUnion) == 0: # This is the first file that we found a union with this # name in, record the union as part of the file. uniqueFilenameForUnion = t.filename() else: # We already found a file that contains a union with # this name. if len(filenamesForUnion) == 1: # This is the first time we found a union with this # name in another file. for f in filenamesForUnion: # Filter out unions with this name from the # unions for the file where we previously found # them. unionsForFilename = self.unionsPerFilename[f] unionsForFilename = filter(lambda u: u.name != t.name, unionsForFilename) if len(unionsForFilename) == 0: del self.unionsPerFilename[f] else: self.unionsPerFilename[f] = unionsForFilename # Unions with this name appear in multiple files, record # the filename as None, so that we can detect that. uniqueFilenameForUnion = None self.unionsPerFilename[uniqueFilenameForUnion].append(t) filenamesForUnion.add(t.filename()) def getInterface(self, ifname): return self.interfaces[ifname] def getDescriptors(self, **filters): """Gets the descriptors that match the given filters.""" curr = self.descriptors # Collect up our filters, because we may have a webIDLFile filter that # we always want to apply first. tofilter = [] for key, val in filters.iteritems(): if key == 'webIDLFile': # Special-case this part to make it fast, since most of our # getDescriptors calls are conditioned on a webIDLFile. We may # not have this key, in which case we have no descriptors # either. curr = self.descriptorsByFile.get(val, []) continue elif key == 'hasInterfaceObject': getter = lambda x: (not x.interface.isExternal() and x.interface.hasInterfaceObject()) elif key == 'hasInterfacePrototypeObject': getter = lambda x: (not x.interface.isExternal() and x.interface.hasInterfacePrototypeObject()) elif key == 'hasInterfaceOrInterfacePrototypeObject': getter = lambda x: x.hasInterfaceOrInterfacePrototypeObject() elif key == 'isCallback': getter = lambda x: x.interface.isCallback() elif key == 'isExternal': getter = lambda x: x.interface.isExternal() elif key == 'isJSImplemented': getter = lambda x: x.interface.isJSImplemented() elif key == 'isNavigatorProperty': getter = lambda x: x.interface.isNavigatorProperty() elif key == 'isExposedInAnyWorker': getter = lambda x: x.interface.isExposedInAnyWorker() elif key == 'isExposedInWorkerDebugger': getter = lambda x: x.interface.isExposedInWorkerDebugger() elif key == 'isExposedInAnyWorklet': getter = lambda x: x.interface.isExposedInAnyWorklet() elif key == 'isExposedInSystemGlobals': getter = lambda x: x.interface.isExposedInSystemGlobals() elif key == 'isExposedInWindow': getter = lambda x: x.interface.isExposedInWindow() else: # Have to watch out: just closing over "key" is not enough, # since we're about to mutate its value getter = (lambda attrName: lambda x: getattr(x, attrName))(key) tofilter.append((getter, val)) for f in tofilter: curr = filter(lambda x: f[0](x) == f[1], curr) return curr def getEnums(self, webIDLFile): return filter(lambda e: e.filename() == webIDLFile, self.enums) def getDictionaries(self, webIDLFile): return filter(lambda d: d.filename() == webIDLFile, self.dictionaries) def getCallbacks(self, webIDLFile): return filter(lambda c: c.filename() == webIDLFile, self.callbacks) def getDescriptor(self, interfaceName): """ Gets the appropriate descriptor for the given interface name. """ # We may have optimized out this descriptor, but the chances of anyone # asking about it are then slim. Put the check for that _after_ we've # done our normal lookup. But that means we have to do our normal # lookup in a way that will not throw if it fails. d = self.descriptorsByName.get(interfaceName, None) if d: return d if interfaceName in self.optimizedOutDescriptorNames: raise NoSuchDescriptorError( "No descriptor for '%s', which is a mixin ([NoInterfaceObject] " "and a consequential interface) without an explicit " "Bindings.conf annotation." % interfaceName) raise NoSuchDescriptorError("For " + interfaceName + " found no matches") class NoSuchDescriptorError(TypeError): def __init__(self, str): TypeError.__init__(self, str) def methodReturnsJSObject(method): assert method.isMethod() if method.returnsPromise(): return True for signature in method.signatures(): returnType = signature[0] if returnType.isObject() or returnType.isSpiderMonkeyInterface(): return True return False def MemberIsUnforgeable(member, descriptor): # Note: "or" and "and" return either their LHS or RHS, not # necessarily booleans. Make sure to return a boolean from this # method, because callers will compare its return value to # booleans. return bool((member.isAttr() or member.isMethod()) and not member.isStatic() and (member.isUnforgeable() or descriptor.interface.getExtendedAttribute("Unforgeable"))) class Descriptor(DescriptorProvider): """ Represents a single descriptor for an interface. See Bindings.conf. """ def __init__(self, config, interface, desc): DescriptorProvider.__init__(self) self.config = config self.interface = interface self.wantsXrays = (not interface.isExternal() and interface.isExposedInWindow()) if self.wantsXrays: # We could try to restrict self.wantsXrayExpandoClass further. For # example, we could set it to false if all of our slots store # Gecko-interface-typed things, because we don't use Xray expando # slots for those. But note that we would need to check the types # of not only the members of "interface" but also of all its # ancestors, because those can have members living in our slots too. # For now, do the simple thing. self.wantsXrayExpandoClass = (interface.totalMembersInSlots != 0) # Read the desc, and fill in the relevant defaults. ifaceName = self.interface.identifier.name # For generated iterator interfaces for other iterable interfaces, we # just use IterableIterator as the native type, templated on the # nativeType of the iterable interface. That way we can have a # templated implementation for all the duplicated iterator # functionality. if self.interface.isIteratorInterface(): itrName = self.interface.iterableInterface.identifier.name itrDesc = self.getDescriptor(itrName) nativeTypeDefault = iteratorNativeType(itrDesc) elif self.interface.isExternal(): nativeTypeDefault = "nsIDOM" + ifaceName else: nativeTypeDefault = "mozilla::dom::" + ifaceName self.nativeType = desc.get('nativeType', nativeTypeDefault) # Now create a version of nativeType that doesn't have extra # mozilla::dom:: at the beginning. prettyNativeType = self.nativeType.split("::") if prettyNativeType[0] == "mozilla": prettyNativeType.pop(0) if prettyNativeType[0] == "dom": prettyNativeType.pop(0) self.prettyNativeType = "::".join(prettyNativeType) self.jsImplParent = desc.get('jsImplParent', self.nativeType) # Do something sane for JSObject if self.nativeType == "JSObject": headerDefault = "js/TypeDecls.h" elif self.interface.isCallback() or self.interface.isJSImplemented(): # A copy of CGHeaders.getDeclarationFilename; we can't # import it here, sadly. # Use our local version of the header, not the exported one, so that # test bindings, which don't export, will work correctly. basename = os.path.basename(self.interface.filename()) headerDefault = basename.replace('.webidl', 'Binding.h') else: if not self.interface.isExternal() and self.interface.getExtendedAttribute("HeaderFile"): headerDefault = self.interface.getExtendedAttribute("HeaderFile")[0] elif self.interface.isIteratorInterface(): headerDefault = "mozilla/dom/IterableIterator.h" else: headerDefault = self.nativeType headerDefault = headerDefault.replace("::", "/") + ".h" self.headerFile = desc.get('headerFile', headerDefault) self.headerIsDefault = self.headerFile == headerDefault if self.jsImplParent == self.nativeType: self.jsImplParentHeader = self.headerFile else: self.jsImplParentHeader = self.jsImplParent.replace("::", "/") + ".h" self.notflattened = desc.get('notflattened', False) self.register = desc.get('register', True) self.hasXPConnectImpls = desc.get('hasXPConnectImpls', False) # If we're concrete, we need to crawl our ancestor interfaces and mark # them as having a concrete descendant. self.concrete = (not self.interface.isExternal() and not self.interface.isCallback() and not self.interface.isNamespace() and desc.get('concrete', True)) self.hasUnforgeableMembers = (self.concrete and any(MemberIsUnforgeable(m, self) for m in self.interface.members)) self.operations = { 'IndexedGetter': None, 'IndexedSetter': None, 'IndexedCreator': None, 'IndexedDeleter': None, 'NamedGetter': None, 'NamedSetter': None, 'NamedCreator': None, 'NamedDeleter': None, 'Stringifier': None, 'LegacyCaller': None, 'Jsonifier': None } # Stringifiers and jsonifiers need to be set up whether an interface is # concrete or not, because they're actually prototype methods and hence # can apply to instances of descendant interfaces. Legacy callers and # named/indexed operations only need to be set up on concrete # interfaces, since they affect the JSClass we end up using, not the # prototype object. def addOperation(operation, m): if not self.operations[operation]: self.operations[operation] = m # Since stringifiers go on the prototype, we only need to worry # about our own stringifier, not those of our ancestor interfaces. if not self.interface.isExternal(): for m in self.interface.members: if m.isMethod() and m.isStringifier(): addOperation('Stringifier', m) if m.isMethod() and m.isJsonifier(): addOperation('Jsonifier', m) if self.concrete: self.proxy = False iface = self.interface for m in iface.members: # Don't worry about inheriting legacycallers either: in # practice these are on most-derived prototypes. if m.isMethod() and m.isLegacycaller(): if not m.isIdentifierLess(): raise TypeError("We don't support legacycaller with " "identifier.\n%s" % m.location) if len(m.signatures()) != 1: raise TypeError("We don't support overloaded " "legacycaller.\n%s" % m.location) addOperation('LegacyCaller', m) while iface: for m in iface.members: if not m.isMethod(): continue def addIndexedOrNamedOperation(operation, m): if m.isIndexed(): operation = 'Indexed' + operation else: assert m.isNamed() operation = 'Named' + operation addOperation(operation, m) if m.isGetter(): addIndexedOrNamedOperation('Getter', m) if m.isSetter(): addIndexedOrNamedOperation('Setter', m) if m.isCreator(): addIndexedOrNamedOperation('Creator', m) if m.isDeleter(): addIndexedOrNamedOperation('Deleter', m) if m.isLegacycaller() and iface != self.interface: raise TypeError("We don't support legacycaller on " "non-leaf interface %s.\n%s" % (iface, iface.location)) iface.setUserData('hasConcreteDescendant', True) iface = iface.parent self.proxy = (self.supportsIndexedProperties() or (self.supportsNamedProperties() and not self.hasNamedPropertiesObject) or self.hasNonOrdinaryGetPrototypeOf()) if self.proxy: if (not self.operations['IndexedGetter'] and (self.operations['IndexedSetter'] or self.operations['IndexedDeleter'] or self.operations['IndexedCreator'])): raise SyntaxError("%s supports indexed properties but does " "not have an indexed getter.\n%s" % (self.interface, self.interface.location)) if (not self.operations['NamedGetter'] and (self.operations['NamedSetter'] or self.operations['NamedDeleter'] or self.operations['NamedCreator'])): raise SyntaxError("%s supports named properties but does " "not have a named getter.\n%s" % (self.interface, self.interface.location)) iface = self.interface while iface: iface.setUserData('hasProxyDescendant', True) iface = iface.parent if desc.get('wantsQI', None) is not None: self._wantsQI = desc.get('wantsQI', None) self.wrapperCache = (not self.interface.isCallback() and not self.interface.isIteratorInterface() and desc.get('wrapperCache', True)) # Nasty temporary hack for supporting both DOM and SpiderMonkey promises # without too much pain if self.interface.identifier.name == "Promise": assert self.wrapperCache # But really, we're only wrappercached if we have an interface # object (that is, when we're not using SpiderMonkey promises). self.wrapperCache = self.interface.hasInterfaceObject() self.name = interface.identifier.name # self.extendedAttributes is a dict of dicts, keyed on # all/getterOnly/setterOnly and then on member name. Values are an # array of extended attributes. self.extendedAttributes = {'all': {}, 'getterOnly': {}, 'setterOnly': {}} def addExtendedAttribute(attribute, config): def add(key, members, attribute): for member in members: self.extendedAttributes[key].setdefault(member, []).append(attribute) if isinstance(config, dict): for key in ['all', 'getterOnly', 'setterOnly']: add(key, config.get(key, []), attribute) elif isinstance(config, list): add('all', config, attribute) else: assert isinstance(config, str) if config == '*': iface = self.interface while iface: add('all', map(lambda m: m.name, iface.members), attribute) iface = iface.parent else: add('all', [config], attribute) if self.interface.isJSImplemented(): addExtendedAttribute('implicitJSContext', ['constructor']) else: for attribute in ['implicitJSContext']: addExtendedAttribute(attribute, desc.get(attribute, {})) if self.interface.identifier.name == 'Navigator': for m in self.interface.members: if m.isAttr() and m.navigatorObjectGetter: # These getters call ConstructNavigatorObject to construct # the value, and ConstructNavigatorObject needs a JSContext. self.extendedAttributes['all'].setdefault(m.identifier.name, []).append('implicitJSContext') self._binaryNames = desc.get('binaryNames', {}) self._binaryNames.setdefault('__legacycaller', 'LegacyCall') self._binaryNames.setdefault('__stringifier', 'Stringify') if not self.interface.isExternal(): def isTestInterface(iface): return (iface.identifier.name in ["TestInterface", "TestJSImplInterface", "TestRenamedInterface"]) for member in self.interface.members: if not member.isAttr() and not member.isMethod(): continue binaryName = member.getExtendedAttribute("BinaryName") if binaryName: assert isinstance(binaryName, list) assert len(binaryName) == 1 self._binaryNames.setdefault(member.identifier.name, binaryName[0]) # Build the prototype chain. self.prototypeChain = [] parent = interface while parent: self.prototypeChain.insert(0, parent.identifier.name) parent = parent.parent config.maxProtoChainLength = max(config.maxProtoChainLength, len(self.prototypeChain)) def binaryNameFor(self, name): return self._binaryNames.get(name, name) @property def prototypeNameChain(self): return map(lambda p: self.getDescriptor(p).name, self.prototypeChain) @property def parentPrototypeName(self): if len(self.prototypeChain) == 1: return None return self.getDescriptor(self.prototypeChain[-2]).name def hasInterfaceOrInterfacePrototypeObject(self): # Forward-declared interfaces don't need either interface object or # interface prototype object as they're going to use QI. if self.interface.isExternal(): return False return self.interface.hasInterfaceObject() or self.interface.hasInterfacePrototypeObject() @property def hasNamedPropertiesObject(self): if self.interface.isExternal(): return False return self.isGlobal() and self.supportsNamedProperties() def getExtendedAttributes(self, member, getter=False, setter=False): def ensureValidThrowsExtendedAttribute(attr): if (attr is not None and attr is not True): raise TypeError("Unknown value for 'Throws': " + attr[0]) def maybeAppendInfallibleToAttrs(attrs, throws): ensureValidThrowsExtendedAttribute(throws) if throws is None: attrs.append("infallible") name = member.identifier.name throws = self.interface.isJSImplemented() or member.getExtendedAttribute("Throws") if member.isMethod(): # JSObject-returning [NewObject] methods must be fallible, # since they have to (fallibly) allocate the new JSObject. if (member.getExtendedAttribute("NewObject") and methodReturnsJSObject(member)): throws = True attrs = self.extendedAttributes['all'].get(name, []) maybeAppendInfallibleToAttrs(attrs, throws) return attrs assert member.isAttr() assert bool(getter) != bool(setter) key = 'getterOnly' if getter else 'setterOnly' attrs = self.extendedAttributes['all'].get(name, []) + self.extendedAttributes[key].get(name, []) if throws is None: throwsAttr = "GetterThrows" if getter else "SetterThrows" throws = member.getExtendedAttribute(throwsAttr) maybeAppendInfallibleToAttrs(attrs, throws) return attrs def supportsIndexedProperties(self): return self.operations['IndexedGetter'] is not None def supportsNamedProperties(self): return self.operations['NamedGetter'] is not None def hasNonOrdinaryGetPrototypeOf(self): return self.interface.getExtendedAttribute("NonOrdinaryGetPrototypeOf") def needsHeaderInclude(self): """ An interface doesn't need a header file if it is not concrete, not pref-controlled, has no prototype object, has no static methods or attributes and has no parent. The parent matters because we assert things about refcounting that depend on the actual underlying type if we have a parent. """ return (self.interface.isExternal() or self.concrete or self.interface.hasInterfacePrototypeObject() or any((m.isAttr() or m.isMethod()) and m.isStatic() for m in self.interface.members) or self.interface.parent) def hasThreadChecks(self): # isExposedConditionally does not necessarily imply thread checks # (since at least [SecureContext] is independent of them), but we're # only used to decide whether to include nsThreadUtils.h, so we don't # worry about that. return ((self.isExposedConditionally() and not self.interface.isExposedInWindow()) or self.interface.isExposedInSomeButNotAllWorkers()) def isExposedConditionally(self): return (self.interface.isExposedConditionally() or self.interface.isExposedInSomeButNotAllWorkers()) def needsXrayResolveHooks(self): """ Generally, any interface with NeedResolve needs Xray resolveOwnProperty and enumerateOwnProperties hooks. But for the special case of plugin-loading elements, we do NOT want those, because we don't want to instantiate plug-ins simply due to chrome touching them and that's all those hooks do on those elements. So we special-case those here. """ return (self.interface.getExtendedAttribute("NeedResolve") and self.interface.identifier.name not in ["HTMLObjectElement", "HTMLEmbedElement", "HTMLAppletElement"]) def needsXrayNamedDeleterHook(self): return self.operations["NamedDeleter"] is not None def needsSpecialGenericOps(self): """ Returns true if this descriptor requires generic ops other than GenericBindingMethod/GenericBindingGetter/GenericBindingSetter. In practice we need to do this if our this value might be an XPConnect object or if we need to coerce null/undefined to the global. """ return self.hasXPConnectImpls or self.interface.isOnGlobalProtoChain() def isGlobal(self): """ Returns true if this is the primary interface for a global object of some sort. """ return (self.interface.getExtendedAttribute("Global") or self.interface.getExtendedAttribute("PrimaryGlobal")) @property def namedPropertiesEnumerable(self): """ Returns whether this interface should have enumerable named properties """ assert self.proxy assert self.supportsNamedProperties() iface = self.interface while iface: if iface.getExtendedAttribute("LegacyUnenumerableNamedProperties"): return False iface = iface.parent return True @property def registersGlobalNamesOnWindow(self): return (not self.interface.isExternal() and self.interface.hasInterfaceObject() and self.interface.isExposedInWindow() and self.register) def getDescriptor(self, interfaceName): """ Gets the appropriate descriptor for the given interface name. """ return self.config.getDescriptor(interfaceName) # Some utility methods def getTypesFromDescriptor(descriptor): """ Get all argument and return types for all members of the descriptor """ members = [m for m in descriptor.interface.members] if descriptor.interface.ctor(): members.append(descriptor.interface.ctor()) members.extend(descriptor.interface.namedConstructors) signatures = [s for m in members if m.isMethod() for s in m.signatures()] types = [] for s in signatures: assert len(s) == 2 (returnType, arguments) = s types.append(returnType) types.extend(a.type for a in arguments) types.extend(a.type for a in members if a.isAttr()) if descriptor.interface.maplikeOrSetlikeOrIterable: maplikeOrSetlikeOrIterable = descriptor.interface.maplikeOrSetlikeOrIterable if maplikeOrSetlikeOrIterable.hasKeyType(): types.append(maplikeOrSetlikeOrIterable.keyType) if maplikeOrSetlikeOrIterable.hasValueType(): types.append(maplikeOrSetlikeOrIterable.valueType) return types def getFlatTypes(types): retval = set() for type in types: type = type.unroll() if type.isUnion(): retval |= set(type.flatMemberTypes) else: retval.add(type) return retval def getTypesFromDictionary(dictionary): """ Get all member types for this dictionary """ types = [] curDict = dictionary while curDict: types.extend([m.type for m in curDict.members]) curDict = curDict.parent return types def getTypesFromCallback(callback): """ Get the types this callback depends on: its return type and the types of its arguments. """ sig = callback.signatures()[0] types = [sig[0]] # Return type types.extend(arg.type for arg in sig[1]) # Arguments return types def getAllTypes(descriptors, dictionaries, callbacks): """ Generate all the types we're dealing with. For each type, a tuple containing type, dictionary is yielded. The dictionary can be None if the type does not come from a dictionary. """ for d in descriptors: if d.interface.isExternal(): continue for t in getTypesFromDescriptor(d): yield (t, None) for dictionary in dictionaries: for t in getTypesFromDictionary(dictionary): yield (t, dictionary) for callback in callbacks: for t in getTypesFromCallback(callback): yield (t, None) def iteratorNativeType(descriptor): assert descriptor.interface.isIterable() iterableDecl = descriptor.interface.maplikeOrSetlikeOrIterable assert iterableDecl.isPairIterator() return "mozilla::dom::IterableIterator<%s>" % descriptor.nativeType