Add a new bindings2/scripts directory for Dart bindings

sky/engine/bindings2/scripts/dart_types.py

Index: sky/engine/bindings2/scripts/dart_types.py
diff --git a/sky/engine/bindings2/scripts/dart_types.py b/sky/engine/bindings2/scripts/dart_types.py
new file mode 100644
index 0000000000000000000000000000000000000000..caaf17a47977afe573640f127aca17ab63b213a7
--- /dev/null
+++ b/sky/engine/bindings2/scripts/dart_types.py
@@ -0,0 +1,874 @@
+# Copyright (C) 2013 Google Inc. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Functions for type handling and type conversion (Blink/C++ <-> Dart:HTML).
+
+Extends IdlType and IdlUnionType with C++-specific properties, methods, and
+class methods.
+
+Spec:
+http://www.w3.org/TR/WebIDL/#es-type-mapping
+
+Design doc: http://www.chromium.org/developers/design-documents/idl-compiler
+"""
+
+import posixpath
+from idl_types import IdlTypeBase, IdlType, IdlUnionType, TYPE_NAMES, IdlArrayOrSequenceType
+
+import dart_attributes
+from dart_utilities import DartUtilities
+from v8_globals import includes
+
+
+################################################################################
+# CPP -specific handling of IDL types for Dart:Blink
+################################################################################
+
+NON_WRAPPER_TYPES = frozenset([
+    'CompareHow',
+    'EventHandler',
+    'EventListener',
+    'MediaQueryListListener',
+    'NodeFilter',
+    'SerializedScriptValue',
+])
+TYPED_ARRAYS = {
+    # (cpp_type, dart_type), used by constructor templates
+    'ArrayBuffer': (None, 'ByteBuffer'),
+    'ArrayBufferView': (None, 'ByteData'),
+    'Float32Array': ('float', 'Float32List'),
+    'Float64Array': ('double', 'Float64List'),
+    'Int8Array': ('signed char', 'Int8List'),
+    'Int16Array': ('short', 'Int16List'),
+    'Int32Array': ('int', 'Int32List'),
+    'Uint8Array': ('unsigned char', 'Uint8List'),
+    'Uint8ClampedArray': ('unsigned char', 'Uint8ClampedList'),
+    'Uint16Array': ('unsigned short', 'Uint16List'),
+    'Uint32Array': ('unsigned int', 'Uint32List'),
+}
+
+
+IdlTypeBase.is_typed_array_type = property(
+    lambda self: self.base_type in TYPED_ARRAYS)
+
+
+IdlType.is_wrapper_type = property(
+    lambda self: (self.is_interface_type and
+                  self.base_type not in NON_WRAPPER_TYPES))
+
+
+################################################################################
+# C++ types
+################################################################################
+
+CPP_TYPE_SAME_AS_IDL_TYPE = set([
+    'double',
+    'float',
+    'long long',
+    'unsigned long long',
+])
+CPP_INT_TYPES = set([
+    'byte',
+    'long',
+    'short',
+])
+CPP_UNSIGNED_TYPES = set([
+    'octet',
+    'unsigned int',
+    'unsigned long',
+    'unsigned short',
+])
+CPP_SPECIAL_CONVERSION_RULES = {
+    'CompareHow': 'Range::CompareHow',
+    'Date': 'double',
+    'EventHandler': 'EventListener*',
+    'MediaQueryListListener': 'RefPtrWillBeRawPtr<MediaQueryListListener>',
+    'Promise': 'ScriptPromise',
+    'ScriptValue': 'ScriptValue',
+    # FIXME: Eliminate custom bindings for XPathNSResolver  http://crbug.com/345529
+    'XPathNSResolver': 'RefPtrWillBeRawPtr<XPathNSResolver>',
+    'boolean': 'bool',
+    'unrestricted double': 'double',
+    'unrestricted float': 'float',
+}
+
+
+def cpp_type(idl_type, extended_attributes=None, raw_type=False, used_as_rvalue_type=False, used_as_variadic_argument=False, used_in_cpp_sequence=False):
+    """Returns C++ type corresponding to IDL type.
+
+    |idl_type| argument is of type IdlType, while return value is a string
+
+    Args:
+        idl_type:
+            IdlType
+        raw_type:
+            bool, True if idl_type's raw/primitive C++ type should be returned.
+        used_as_rvalue_type:
+            bool, True if the C++ type is used as an argument or the return
+            type of a method.
+        used_as_variadic_argument:
+            bool, True if the C++ type is used as a variadic argument of a method.
+        used_in_cpp_sequence:
+            bool, True if the C++ type is used as an element of a container.
+            Containers can be an array, a sequence or a dictionary.
+    """
+    extended_attributes = extended_attributes or {}
+    idl_type = idl_type.preprocessed_type
+
+    # Composite types
+    native_array_element_type = idl_type.native_array_element_type
+    if native_array_element_type:
+        return cpp_template_type('Vector', native_array_element_type.cpp_type_args(used_in_cpp_sequence=True))
+
+    # Simple types
+    base_idl_type = idl_type.base_type
+
+    if base_idl_type in CPP_TYPE_SAME_AS_IDL_TYPE:
+        return base_idl_type
+    if base_idl_type in CPP_INT_TYPES:
+        return 'int'
+    if base_idl_type in CPP_UNSIGNED_TYPES:
+        return 'unsigned'
+    if base_idl_type in CPP_SPECIAL_CONVERSION_RULES:
+        return CPP_SPECIAL_CONVERSION_RULES[base_idl_type]
+
+    if base_idl_type in NON_WRAPPER_TYPES:
+        return ('PassRefPtr<%s>' if used_as_rvalue_type else 'RefPtr<%s>') % base_idl_type
+    if base_idl_type in ('DOMString', 'ByteString', 'ScalarValueString'):
+        return 'String'
+
+    if idl_type.is_typed_array_type and raw_type:
+        return 'RefPtr<%s>' % base_idl_type
+    if idl_type.is_callback_interface:
+        return 'OwnPtr<%s>' % base_idl_type
+    if idl_type.is_interface_type:
+        implemented_as_class = idl_type.implemented_as
+        if raw_type:
+            return implemented_as_class + '*'
+        new_type = 'Member' if used_in_cpp_sequence else 'RawPtr'
+        ptr_type = 'PassRefPtr' if used_as_rvalue_type else 'RefPtr'
+        return cpp_template_type(ptr_type, implemented_as_class)
+
+    # Default, assume native type is a pointer with same type name as idl type
+    return base_idl_type + '*'
+
+
+def cpp_type_union(idl_type, extended_attributes=None, used_as_rvalue_type=False, will_be_in_heap_object=False):
+    return (member_type.cpp_type for member_type in idl_type.member_types)
+
+
+# Allow access as idl_type.cpp_type if no arguments
+IdlTypeBase.cpp_type = property(cpp_type)
+IdlTypeBase.cpp_type_args = cpp_type
+IdlUnionType.cpp_type = property(cpp_type_union)
+IdlUnionType.cpp_type_args = cpp_type_union
+
+
+IdlTypeBase.native_array_element_type = None
+IdlArrayOrSequenceType.native_array_element_type = property(
+    lambda self: self.element_type)
+
+
+def cpp_template_type(template, inner_type):
+    """Returns C++ template specialized to type, with space added if needed."""
+    if inner_type.endswith('>'):
+        format_string = '{template}<{inner_type} >'
+    else:
+        format_string = '{template}<{inner_type}>'
+    return format_string.format(template=template, inner_type=inner_type)
+
+
+def dart_type(interface_name):
+    return 'Dart' + str(interface_name)
+
+
+# [ImplementedAs]
+# This handles [ImplementedAs] on interface types, not [ImplementedAs] in the
+# interface being generated. e.g., given:
+#   Foo.idl: interface Foo {attribute Bar bar};
+#   Bar.idl: [ImplementedAs=Zork] interface Bar {};
+# when generating bindings for Foo, the [ImplementedAs] on Bar is needed.
+# This data is external to Foo.idl, and hence computed as global information in
+# compute_interfaces_info.py to avoid having to parse IDLs of all used interfaces.
+IdlType.implemented_as_interfaces = {}
+
+
+def implemented_as(idl_type):
+    base_idl_type = idl_type.base_type
+    if base_idl_type in IdlType.implemented_as_interfaces:
+        return IdlType.implemented_as_interfaces[base_idl_type]
+    return base_idl_type
+
+
+IdlType.implemented_as = property(implemented_as)
+
+IdlType.set_implemented_as_interfaces = classmethod(
+    lambda cls, new_implemented_as_interfaces:
+        cls.implemented_as_interfaces.update(new_implemented_as_interfaces))
+
+
+
+################################################################################
+# Includes
+################################################################################
+
+def includes_for_cpp_class(class_name, relative_dir_posix):
+    return set([posixpath.join('bindings', relative_dir_posix, class_name + '.h')])
+
+# TODO(terry): Will we need this group header for dart:blink?
+INCLUDES_FOR_TYPE = {
+    'object': set(),
+    'CompareHow': set(),
+    'EventHandler': set(),
+    'EventListener': set(),
+    'MediaQueryListListener': set(['sky/engine/core/css/MediaQueryListListener.h']),
+    'NodeList': set(['sky/engine/core/dom/NodeList.h',
+                     'sky/engine/core/dom/StaticNodeList.h']),
+    'ScriptValue': set(['sky/engine/tonic/dart_value.h']),
+}
+
+
+def includes_for_type(idl_type):
+    idl_type = idl_type.preprocessed_type
+
+    # Composite types
+    if idl_type.native_array_element_type:
+        return includes_for_type(idl_type)
+
+    # Simple types
+    base_idl_type = idl_type.base_type
+    if base_idl_type in INCLUDES_FOR_TYPE:
+        return INCLUDES_FOR_TYPE[base_idl_type]
+    if idl_type.is_basic_type:
+        return set()
+    if idl_type.is_typed_array_type:
+        # Typed array factory methods are already provided by DartUtilities.h.
+        return set([])
+    if base_idl_type.endswith('ConstructorConstructor'):
+        # FIXME: rename to NamedConstructor
+        # FIXME: replace with a [NamedConstructorAttribute] extended attribute
+        # Ending with 'ConstructorConstructor' indicates a named constructor,
+        # and these do not have header files, as they are part of the generated
+        # bindings for the interface
+        return set()
+    if base_idl_type.endswith('Constructor'):
+        # FIXME: replace with a [ConstructorAttribute] extended attribute
+        base_idl_type = idl_type.constructor_type_name
+    if base_idl_type not in component_dir:
+        return set()
+    return set(['gen/sky/bindings/Dart%s.h' % base_idl_type])
+
+IdlType.includes_for_type = property(includes_for_type)
+IdlUnionType.includes_for_type = property(
+    lambda self: set.union(*[includes_for_type(member_type)
+                             for member_type in self.member_types]))
+
+
+def add_includes_for_type(idl_type):
+    includes.update(idl_type.includes_for_type)
+
+IdlTypeBase.add_includes_for_type = add_includes_for_type
+IdlUnionType.add_includes_for_type = add_includes_for_type
+
+
+def includes_for_interface(interface_name):
+    return IdlType(interface_name).includes_for_type
+
+
+def add_includes_for_interface(interface_name):
+    includes.update(includes_for_interface(interface_name))
+
+
+component_dir = {}
+
+
+def set_component_dirs(new_component_dirs):
+    component_dir.update(new_component_dirs)
+
+
+################################################################################
+# Dart -> C++
+################################################################################
+
+# TODO(terry): Need to fix to handle getter/setters for onEvent.
+DART_FIX_ME = 'DART_UNIMPLEMENTED(/* Conversion unimplemented*/);'
+
+# For a given IDL type, the DartHandle to C++ conversion.
+DART_TO_CPP_VALUE = {
+    # Basic
+    'Date': 'DartUtilities::dartToDate(args, {index}, exception)',
+    'DOMString': 'DartConverter<String>::FromArguments{null_check}(args, {index}, exception, {auto_scope})',
+    'ByteString': 'DartUtilities::dartToByteString{null_check}(args, {index}, exception, {auto_scope})',
+    'ScalarValueString': 'DartUtilities::dartToScalarValueString{null_check}(args, {index}, exception, {auto_scope})',
+    'boolean': 'DartConverter<bool>::FromArguments(args, {index}, exception)',
+    'float': 'static_cast<float>(DartConverter<double>::FromArguments(args, {index}, exception))',
+    'unrestricted float': 'static_cast<float>(DartConverter<double>::FromArguments(args, {index}, exception))',
+    'double': 'DartConverter<double>::FromArguments(args, {index}, exception)',
+    'unrestricted double': 'DartConverter<double>::FromArguments(args, {index}, exception)',
+    # FIXME(vsm): Inconsistent with V8.
+    'byte': 'DartConverter<unsigned>::FromArguments(args, {index}, exception)',
+    'octet': 'DartConverter<unsigned>::FromArguments(args, {index}, exception)',
+    'short': 'DartConverter<int>::FromArguments(args, {index}, exception)',
+    'unsigned short': 'DartConverter<unsigned>::FromArguments(args, {index}, exception)',
+    'long': 'DartConverter<int>::FromArguments(args, {index}, exception)',
+    'unsigned long': 'DartConverter<unsigned>::FromArguments(args, {index}, exception)',
+    'long long': 'DartConverter<long long>::FromArguments(args, {index}, exception)',
+    'unsigned long long': 'DartConverter<unsigned long long>::FromArguments(args, {index}, exception)',
+    # Interface types
+    'CompareHow': 'static_cast<Range::CompareHow>(0) /* FIXME, DART_TO_CPP_VALUE[CompareHow] */',
+    'EventTarget': '0 /* FIXME, DART_TO_CPP_VALUE[EventTarget] */',
+    'MediaQueryListListener': 'nullptr /* FIXME, DART_TO_CPP_VALUE[MediaQueryListener] */',
+    'NodeFilter': 'nullptr /* FIXME, DART_TO_CPP_VALUE[NodeFilter] */',
+    'Promise': 'DartUtilities::dartToScriptPromise{null_check}(args, {index})',
+    'SerializedScriptValue': 'nullptr /* FIXME, DART_TO_CPP_VALUE[SerializedScriptValue] */',
+    'ScriptValue': 'DartUtilities::dartToScriptValue{null_check}(args, {index})',
+    # FIXME(vsm): Why don't we have an entry for Window? V8 does.
+    # I think I removed this as the Window object is more special in V8 - it's the
+    # global context as well.  Do we need to special case it?
+    'XPathNSResolver': 'nullptr /* FIXME, DART_TO_CPP_VALUE[XPathNSResolver] */',
+    # FIXME(vsm): This is an enum type (defined in StorageQuota.idl).
+    # We should handle it automatically, but map to a String for now.
+    'StorageType': 'DartUtilities::dartToString(args, {index}, exception, {auto_scope})',
+}
+
+
+def dart_value_to_cpp_value(idl_type, extended_attributes, variable_name,
+                            null_check, has_type_checking_interface,
+                            index, auto_scope=True):
+    # Composite types
+    native_array_element_type = idl_type.native_array_element_type
+    if native_array_element_type:
+        return dart_value_to_cpp_value_array_or_sequence(native_array_element_type, variable_name, index)
+
+    # Simple types
+    idl_type = idl_type.preprocessed_type
+    add_includes_for_type(idl_type)
+    base_idl_type = idl_type.base_type
+
+    if 'EnforceRange' in extended_attributes:
+        arguments = ', '.join([variable_name, 'EnforceRange', 'exceptionState'])
+    elif idl_type.is_integer_type:  # NormalConversion
+        arguments = ', '.join([variable_name, 'es'])
+    else:
+        arguments = variable_name
+
+    if base_idl_type in DART_TO_CPP_VALUE:
+        cpp_expression_format = DART_TO_CPP_VALUE[base_idl_type]
+    elif idl_type.is_typed_array_type:
+        # FIXME(vsm): V8 generates a type check here as well. Do we need one?
+        # FIXME(vsm): When do we call the externalized version? E.g., see
+        # bindings/dart/custom/DartWaveShaperNodeCustom.cpp - it calls
+        # DartUtilities::dartToExternalizedArrayBufferView instead.
+        # V8 always converts null here
+        cpp_expression_format = ('DartUtilities::dartTo{idl_type}WithNullCheck(args, {index}, exception)')
+    elif idl_type.is_callback_interface:
+        cpp_expression_format = ('Dart{idl_type}::create{null_check}(args, {index}, exception)')
+    else:
+        cpp_expression_format = ('DartConverter<{implemented_as}*>::FromArguments{null_check}(args, {index}, exception)')
+
+    # We allow the calling context to force a null check to handle
+    # some cases that require calling context info.  V8 handles all
+    # of this differently, and we may wish to reconsider this approach
+    check_string = ''
+    if null_check or allow_null(idl_type, extended_attributes,
+                                has_type_checking_interface):
+        check_string = 'WithNullCheck'
+    elif allow_empty(idl_type, extended_attributes):
+        check_string = 'WithEmptyCheck'
+    return cpp_expression_format.format(null_check=check_string,
+                                        arguments=arguments,
+                                        index=index,
+                                        idl_type=base_idl_type,
+                                        implemented_as=idl_type.implemented_as,
+                                        auto_scope=DartUtilities.bool_to_cpp(auto_scope))
+
+
+def dart_value_to_cpp_value_array_or_sequence(native_array_element_type, variable_name, index):
+    # Index is None for setters, index (starting at 0) for method arguments,
+    # and is used to provide a human-readable exception message
+    if index is None:
+        index = 0  # special case, meaning "setter"
+#    else:
+#        index += 1  # human-readable index
+    if (native_array_element_type.is_interface_type):
+        this_cpp_type = None
+        ref_ptr_type = 'RefPtr'
+        # FIXME(vsm): We're not using ref_ptr_type....
+        expression_format = '{variable_name} = DartConverter<Vector<{native_array_element_type}>>::FromArguments(args, {index}, exception)'
+        add_includes_for_type(native_array_element_type)
+    else:
+        ref_ptr_type = None
+        this_cpp_type = native_array_element_type.cpp_type
+        expression_format = '{variable_name} = DartConverter<Vector<{cpp_type}>>::FromArguments(args, {index}, exception)'
+
+    expression = expression_format.format(native_array_element_type=native_array_element_type.name,
+                                          cpp_type=this_cpp_type, index=index, ref_ptr_type=ref_ptr_type,
+                                          variable_name=variable_name)
+    return expression
+
+
+def dart_value_to_local_cpp_value(idl_type, extended_attributes, variable_name,
+                                  null_check, has_type_checking_interface,
+                                  index=None, auto_scope=True):
+    """Returns an expression that converts a Dart value to a C++ value as a local value."""
+    idl_type = idl_type.preprocessed_type
+
+    cpp_value = dart_value_to_cpp_value(
+        idl_type, extended_attributes, variable_name,
+        null_check, has_type_checking_interface,
+        index, auto_scope)
+
+    return cpp_value
+
+IdlTypeBase.dart_value_to_local_cpp_value = dart_value_to_local_cpp_value
+#IdlUnionType.dart_value_to_local_cpp_value = dart_value_to_local_cpp_value
+
+
+# Insure that we don't use C++ reserved names.  Today on default is a problem.
+def check_reserved_name(name):
+    return 'default_value' if (name == 'default') else name
+
+
+################################################################################
+# C++ -> V8
+################################################################################
+
+def preprocess_idl_type(idl_type):
+    if idl_type.is_enum:
+        # Enumerations are internally DOMStrings
+        return IdlType('DOMString')
+    if (idl_type.name == 'Any' or idl_type.is_callback_function):
+        return IdlType('ScriptValue')
+    return idl_type
+
+IdlTypeBase.preprocessed_type = property(preprocess_idl_type)
+IdlUnionType.preprocessed_type = property(preprocess_idl_type)
+
+
+def preprocess_idl_type_and_value(idl_type, cpp_value, extended_attributes):
+    """Returns IDL type and value, with preliminary type conversions applied."""
+    idl_type = idl_type.preprocessed_type
+    if idl_type.name == 'Promise':
+        idl_type = IdlType('ScriptPromise')
+
+    # FIXME(vsm): V8 maps 'long long' and 'unsigned long long' to double
+    # as they are not representable in ECMAScript.  Should we do the same?
+
+    # HTML5 says that unsigned reflected attributes should be in the range
+    # [0, 2^31). When a value isn't in this range, a default value (or 0)
+    # should be returned instead.
+    extended_attributes = extended_attributes or {}
+    if ('Reflect' in extended_attributes and
+        idl_type.base_type in ['unsigned long', 'unsigned short']):
+        cpp_value = cpp_value.replace('getUnsignedIntegralAttribute',
+                                      'getIntegralAttribute')
+        cpp_value = 'std::max(0, %s)' % cpp_value
+    return idl_type, cpp_value
+
+
+IDL_TO_DART_TYPE = {
+    'DOMString': 'String',
+    'void': 'void',
+    'boolean': 'bool',
+}
+
+def idl_type_to_dart_type(idl_type):
+    preprocessed_type = str(idl_type.preprocessed_type)
+    dart_type = IDL_TO_DART_TYPE.get(preprocessed_type)
+    if dart_type:
+        return dart_type
+    if idl_type.is_integer_type:
+        return 'int'
+    if idl_type.is_numeric_type:
+        return 'double'
+    native_array_element_type = idl_type.native_array_element_type
+    if native_array_element_type:
+        return 'List<%s>' % native_array_element_type
+    assert preprocessed_type
+    assert idl_type.is_interface_type, "Missing dart type mapping for '%s'" % preprocessed_type
+    return preprocessed_type
+
+
+DART_DEFAULT_VALUES_BY_TYPE = {
+    'String': '""',
+    'int': '0',
+    'double': '0',
+    'bool': 'false',
+}
+
+def dart_default_value(dart_type, argument=None):
+    # TODO(eseidel): Maybe take the idl_type instead?
+    # if argument.default_value:
+    #     return argument.default_value
+    default_value = DART_DEFAULT_VALUES_BY_TYPE.get(dart_type)
+    if default_value:
+        return default_value
+    idl_type = argument.idl_type
+    if idl_type.is_interface_type:
+        return 'null'
+    if idl_type.native_array_element_type:
+        return 'null'
+    assert default_value, "Missing default value mapping for '%s'" % dart_type
+
+
+def dart_conversion_type(idl_type, extended_attributes):
+    """Returns Dart conversion type, adding any additional includes.
+
+    The Dart conversion type is used to select the C++ -> Dart conversion function
+    or setDart*ReturnValue function; it can be an idl_type, a cpp_type, or a
+    separate name for the type of conversion (e.g., 'DOMWrapper').
+    """
+    extended_attributes = extended_attributes or {}
+
+    # Composite types
+    native_array_element_type = idl_type.native_array_element_type
+    if native_array_element_type:
+        if native_array_element_type.is_interface_type:
+            add_includes_for_type(native_array_element_type)
+        return 'array'
+
+    # Simple types
+    base_idl_type = idl_type.base_type
+    # Basic types, without additional includes
+    if base_idl_type in CPP_INT_TYPES or base_idl_type == 'long long':
+        return 'int'
+    if base_idl_type in CPP_UNSIGNED_TYPES or base_idl_type == 'unsigned long long':
+        return 'unsigned'
+    if idl_type.is_string_type:
+        if idl_type.is_nullable:
+            return 'StringOrNull'
+        if 'TreatReturnedNullStringAs' not in extended_attributes:
+            return 'DOMString'
+        treat_returned_null_string_as = extended_attributes['TreatReturnedNullStringAs']
+        if treat_returned_null_string_as == 'Null':
+            return 'StringOrNull'
+        if treat_returned_null_string_as == 'Undefined':
+            return 'StringOrUndefined'
+        raise 'Unrecognized TreatReturnNullStringAs value: "%s"' % treat_returned_null_string_as
+    if idl_type.is_basic_type or base_idl_type == 'ScriptValue':
+        return base_idl_type
+
+    # Data type with potential additional includes
+    add_includes_for_type(idl_type)
+    if base_idl_type in DART_SET_RETURN_VALUE:  # Special dartSetReturnValue treatment
+        return base_idl_type
+
+    # Typed arrays don't have special Dart* classes for Dart.
+    if idl_type.is_typed_array_type:
+        if base_idl_type == 'ArrayBuffer':
+            return 'ArrayBuffer'
+        else:
+            return 'TypedList'
+
+    # Pointer type
+    return 'DOMWrapper'
+
+IdlTypeBase.dart_conversion_type = dart_conversion_type
+
+
+DART_SET_RETURN_VALUE = {
+    'boolean': 'DartConverter<bool>::SetReturnValue(args, {cpp_value})',
+    'int': 'DartConverter<int>::SetReturnValue(args, {cpp_value})',
+    'unsigned': 'DartConverter<unsigned>::SetReturnValue(args, {cpp_value})',
+    'DOMString': 'DartConverter<String>::SetReturnValue(args, {cpp_value}, {auto_scope})',
+    # FIXME(terry): Need to handle checking to byte values > 255 throwing exception.
+    'ByteString': 'DartUtilities::setDartByteStringReturnValue(args, {cpp_value}, {auto_scope})',
+    # FIXME(terry):  Need to make valid unicode; match UTF-16 to U+FFFD REPLACEMENT CHARACTER.
+    'ScalarValueString': 'DartUtilities::setDartScalarValueStringReturnValue(args, {cpp_value}, {auto_scope})',
+    # [TreatNullReturnValueAs]
+    'StringOrNull': 'DartConverter<String>::SetReturnValueWithNullCheck(args, {cpp_value}, {auto_scope})',
+    # FIXME(vsm): How should we handle undefined?
+    'StringOrUndefined': 'DartConverter<String>::SetReturnValueWithNullCheck(args, {cpp_value}, {auto_scope})',
+    'void': '',
+    # We specialize these as well in Dart.
+    'float': 'DartConverter<double>::SetReturnValue(args, {cpp_value})',
+    'unrestricted float': 'DartConverter<double>::SetReturnValue(args, {cpp_value})',
+    'double': 'DartConverter<double>::SetReturnValue(args, {cpp_value})',
+    'unrestricted double': 'DartConverter<double>::SetReturnValue(args, {cpp_value})',
+    # No special function, but instead convert value to Dart_Handle
+    # and then use general Dart_SetReturnValue.
+    'array': 'Dart_SetReturnValue(args, {cpp_value})',
+    'Date': 'Dart_SetReturnValue(args, {cpp_value})',
+    'EventHandler': DART_FIX_ME,
+    'ScriptPromise': 'Dart_SetReturnValue(args, {cpp_value})',
+    'ScriptValue': 'Dart_SetReturnValue(args, {cpp_value})',
+    'SerializedScriptValue': DART_FIX_ME,
+    # DOMWrapper
+    # TODO(terry): Remove ForMainWorld stuff.
+    'DOMWrapperForMainWorld': DART_FIX_ME,
+    # FIXME(vsm): V8 has a fast path. Do we?
+    'DOMWrapperFast': 'DartConverter<{implemented_as}*>::SetReturnValue(args, WTF::getPtr({cpp_value}), {auto_scope})',
+    'DOMWrapperDefault': 'DartConverter<{implemented_as}*>::SetReturnValue(args, WTF::getPtr({cpp_value}), {auto_scope})',
+    # Typed arrays don't have special Dart* classes for Dart.
+    'ArrayBuffer': 'Dart_SetReturnValue(args, DartUtilities::arrayBufferToDart({cpp_value}))',
+    'TypedList': 'Dart_SetReturnValue(args, DartUtilities::arrayBufferViewToDart({cpp_value}))',
+}
+
+
+def dart_set_return_value(idl_type, cpp_value,
+                          extended_attributes=None, script_wrappable='',
+                          release=False, for_main_world=False,
+                          auto_scope=True):
+    """Returns a statement that converts a C++ value to a Dart value and sets it as a return value.
+
+    """
+    def dom_wrapper_conversion_type():
+        if not script_wrappable:
+            return 'DOMWrapperDefault'
+        if for_main_world:
+            return 'DOMWrapperForMainWorld'
+        return 'DOMWrapperFast'
+
+    idl_type, cpp_value = preprocess_idl_type_and_value(idl_type, cpp_value, extended_attributes)
+    this_dart_conversion_type = idl_type.dart_conversion_type(extended_attributes)
+    # SetReturn-specific overrides
+    if this_dart_conversion_type in ['Date', 'EventHandler', 'ScriptPromise', 'ScriptValue', 'SerializedScriptValue', 'array']:
+        # Convert value to Dart and then use general Dart_SetReturnValue
+        # FIXME(vsm): Why do we differ from V8 here? It doesn't have a
+        # creation_context.
+        creation_context = ''
+        if this_dart_conversion_type == 'array':
+            # FIXME: This is not right if the base type is a primitive, DOMString, etc.
+            # What is the right check for base type?
+            base_type = str(idl_type.element_type)
+            if base_type not in DART_TO_CPP_VALUE:
+                if base_type == 'None':
+                    raise Exception('Unknown base type for ' + str(idl_type))
+                creation_context = '<Dart%s>' % base_type
+            if idl_type.is_nullable:
+                creation_context = 'Nullable' + creation_context
+
+        cpp_value = idl_type.cpp_value_to_dart_value(cpp_value, creation_context=creation_context,
+                                                     extended_attributes=extended_attributes)
+    if this_dart_conversion_type == 'DOMWrapper':
+        this_dart_conversion_type = dom_wrapper_conversion_type()
+
+    format_string = DART_SET_RETURN_VALUE[this_dart_conversion_type]
+
+    if release:
+        cpp_value = '%s.release()' % cpp_value
+    statement = format_string.format(cpp_value=cpp_value,
+                                     implemented_as=idl_type.implemented_as,
+                                     type_name=idl_type.name,
+                                     script_wrappable=script_wrappable,
+                                     auto_scope=DartUtilities.bool_to_cpp(auto_scope))
+    return statement
+
+
+def dart_set_return_value_union(idl_type, cpp_value, extended_attributes=None,
+                              script_wrappable='', release=False, for_main_world=False,
+                              auto_scope=True):
+    """
+    release: can be either False (False for all member types) or
+             a sequence (list or tuple) of booleans (if specified individually).
+    """
+
+    return [
+        # FIXME(vsm): Why do we use 'result' instead of cpp_value as V8?
+        member_type.dart_set_return_value('result' + str(i),
+                                        extended_attributes,
+                                        script_wrappable,
+                                        release and release[i],
+                                        for_main_world,
+                                        auto_scope)
+            for i, member_type in
+            enumerate(idl_type.member_types)]
+
+IdlTypeBase.dart_set_return_value = dart_set_return_value
+IdlUnionType.dart_set_return_value = dart_set_return_value_union
+
+IdlType.release = property(lambda self: self.is_interface_type)
+IdlUnionType.release = property(
+    lambda self: [member_type.is_interface_type
+                  for member_type in self.member_types])
+
+
+CPP_VALUE_TO_DART_VALUE = {
+    # Built-in types
+    # FIXME(vsm): V8 uses DateOrNull - do we need a null check?
+    'Date': 'DartUtilities::dateToDart({cpp_value})',
+    'DOMString': 'DartConverter<String>::ToDart(DartState::Current(), {cpp_value})',
+    'boolean': 'DartConverter<bool>::ToDart({cpp_value})',
+    'int': 'DartConverter<int>::ToDart({cpp_value})',
+    'unsigned': 'DartConverter<unsigned>::ToDart({cpp_value})',
+    'float': 'DartConverter<double>::ToDart({cpp_value})',
+    'unrestricted float': 'DartConverter<double>::ToDart({cpp_value})',
+    'double': 'DartConverter<double>::ToDart({cpp_value})',
+    'unrestricted double': 'DartConverter<double>::ToDart({cpp_value})',
+    # FIXME(vsm): Dart_Null?
+    'void': '',
+    # Special cases
+    'EventHandler': '-----OOPS TO DART-EVENT---',
+    # We need to generate the NullCheck version in some cases.
+    'ScriptPromise': 'DartUtilities::scriptPromiseToDart({cpp_value})',
+    'ScriptValue': 'DartUtilities::scriptValueToDart({cpp_value})',
+    'SerializedScriptValue': 'DartUtilities::serializedScriptValueToDart({cpp_value})',
+    # General
+    'array': 'VectorToDart({cpp_value})',
+    'DOMWrapper': 'Dart{idl_type}::toDart({cpp_value})',
+}
+
+
+def cpp_value_to_dart_value(idl_type, cpp_value, creation_context='', extended_attributes=None):
+    """Returns an expression that converts a C++ value to a Dart value."""
+    # the isolate parameter is needed for callback interfaces
+    idl_type, cpp_value = preprocess_idl_type_and_value(idl_type, cpp_value, extended_attributes)
+    this_dart_conversion_type = idl_type.dart_conversion_type(extended_attributes)
+    format_string = CPP_VALUE_TO_DART_VALUE[this_dart_conversion_type]
+    statement = format_string.format(cpp_value=cpp_value, idl_type=idl_type.base_type)
+    return statement
+
+IdlTypeBase.cpp_value_to_dart_value = cpp_value_to_dart_value
+
+# FIXME(leafp) This is horrible, we should do better, but currently this is hard to do
+# in a nice way.  Best solution might be to extend DartStringAdapter to accomodate
+# initialization from constant strings, but better to do that once we're stable
+# on the bots so we can track any performance regression
+CPP_LITERAL_TO_DART_VALUE = {
+    'DOMString': {'nullptr': 'String()',
+                  'String("")': 'String(StringImpl::empty())',
+                  '*': 'DartUtilities::dartToString(DartUtilities::stringToDart({cpp_literal}), exception)'},
+    'ScalarValueString': {'nullptr': 'DartStringAdapter(DartStringPeer::nullString())',
+                          'String("")': 'DartStringAdapter(DartStringPeer::emptyString())',
+                          '*': 'DartUtilities::dartToScalarValueString(DartUtilities::stringToDart({cpp_literal}), exception)'},
+}
+
+
+def literal_cpp_value(idl_type, idl_literal):
+    """Converts an expression that is a valid C++ literal for this type."""
+    # FIXME: add validation that idl_type and idl_literal are compatible
+    literal_value = str(idl_literal)
+    base_type = idl_type.preprocessed_type.base_type
+    if base_type in CPP_UNSIGNED_TYPES:
+        return literal_value + 'u'
+    if base_type in CPP_LITERAL_TO_DART_VALUE:
+        if literal_value in CPP_LITERAL_TO_DART_VALUE[base_type]:
+            format_string = CPP_LITERAL_TO_DART_VALUE[base_type][literal_value]
+        else:
+            format_string = CPP_LITERAL_TO_DART_VALUE[base_type]['*']
+        return format_string.format(cpp_literal=literal_value)
+    return literal_value
+
+IdlType.literal_cpp_value = literal_cpp_value
+
+
+CPP_DEFAULT_VALUE_FOR_CPP_TYPE = {
+    'DOMString': 'String()',
+    'ByteString': 'String()',
+    'ScalarValueString': 'String()',
+    'boolean': 'false',
+    'float': '0.0f',
+    'unrestricted float': '0.0f',
+    'double': '0.0',
+    'unrestricted double': '0.0',
+    'byte': '0',
+    'octet': '0',
+    'short': '0',
+    'unsigned short': '0',
+    'long': '0',
+    'unsigned long': '0',
+    'long long': '0',
+    'unsigned long long': '0',
+}
+
+
+def default_cpp_value_for_cpp_type(idl_type):
+    idl_type = idl_type.preprocessed_type
+    add_includes_for_type(idl_type)
+    base_idl_type = idl_type.base_type
+    if base_idl_type in CPP_DEFAULT_VALUE_FOR_CPP_TYPE:
+        return CPP_DEFAULT_VALUE_FOR_CPP_TYPE[base_idl_type]
+    return 'nullptr'
+
+
+# Override idl_type.name to not suffix orNull to the name, in Dart we always
+# test for null e.g.,
+#
+#      bool isNull = false;
+#      TYPE* result = receiver->GETTER(isNull);
+#      if (isNull)
+#          return;
+#
+def dart_name(idl_type):
+    """Return type name.
+
+    http://heycam.github.io/webidl/#dfn-type-name
+    """
+    base_type = idl_type.base_type
+    base_type_name = TYPE_NAMES.get(base_type, base_type)
+    if idl_type.native_array_element_type:
+        return idl_type.inner_name()
+    return base_type_name
+
+IdlType.name = property(dart_name)
+IdlUnionType.name = property(dart_name)
+
+
+# If True use the WithNullCheck version when converting.
+def allow_null(idl_type, extended_attributes, has_type_checking_interface):
+    if idl_type.base_type in ('DOMString', 'ByteString', 'ScalarValueString'):
+        # This logic is in cpp_types in v8_types.py, since they handle
+        # this using the V8StringResource type.  We handle it here
+        if (extended_attributes.get('TreatNullAs') == 'NullString' or
+            extended_attributes.get('TreatUndefinedAs') == 'NullString'):
+            return True
+
+        if extended_attributes.get('Default') == 'NullString':
+            return True
+
+        if extended_attributes.get('Default') == 'Undefined':
+            return True
+
+        if idl_type.is_nullable:
+            return True
+
+        return False
+    else:
+        # This logic is implemented in the methods.cpp template in V8
+        if (idl_type.is_nullable or not has_type_checking_interface):
+            return True
+
+        if extended_attributes.get('Default') == 'Undefined':
+            return True
+
+        return False
+
+
+# If True use the WithEmptyCheck version when converting.
+def allow_empty(idl_type, extended_attributes):
+    if idl_type.base_type in ('DOMString', 'ByteString', 'ScalarValueString'):
+        # This logic is in cpp_types in v8_types.py, since they handle
+        # this using the V8StringResource type.  We handle it here
+        if (extended_attributes.get('TreatNullAs') == 'EmptyString' or
+            extended_attributes.get('TreatUndefinedAs') == 'EmptyString'):
+            return True
+
+        if extended_attributes.get('Default') == 'EmptyString':
+            return True
+
+    return False