Introduce SmallTypedArray IDL type and use it for bufferSubData

Source/bindings/scripts/v8_types.py

 # 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
@@ skipping 36 matching lines @@
 ################################################################################
 # V8-specific handling of IDL types
 ################################################################################
 
 NON_WRAPPER_TYPES = frozenset([
     'Dictionary',
     'EventHandler',
     'EventListener',
     'NodeFilter',
     'SerializedScriptValue',
+    'SmallTypedArray',
 ])
 TYPED_ARRAY_TYPES = frozenset([
     'Float32Array',
     'Float64Array',
     'Int8Array',
     'Int16Array',
     'Int32Array',
     'Uint8Array',
     'Uint8ClampedArray',
     'Uint16Array',
@@ skipping 37 matching lines @@
     'unsigned long',
     'unsigned short',
 ])
 CPP_SPECIAL_CONVERSION_RULES = {
     'Date': 'double',
     'Dictionary': 'Dictionary',
     'EventHandler': 'EventListener*',
     'NodeFilter': 'RefPtrWillBeRawPtr<NodeFilter>',
     'Promise': 'ScriptPromise',
     'ScriptValue': 'ScriptValue',
+    'SmallTypedArray': 'std::pair<void*, size_t>',
     # 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.
@@ skipping 361 matching lines @@
     'unsigned long': 'toUInt32({isolate}, {arguments})',
     'long long': 'toInt64({isolate}, {arguments})',
     'unsigned long long': 'toUInt64({isolate}, {arguments})',
     # Interface types
     'Dictionary': 'Dictionary({v8_value}, {isolate}, exceptionState)',
     'EventTarget': 'toEventTarget({isolate}, {v8_value})',
     'NodeFilter': 'toNodeFilter({v8_value}, info.Holder(), ScriptState::current({isolate}))',
     'Promise': 'ScriptPromise::cast(ScriptState::current({isolate}), {v8_value})',
     'SerializedScriptValue': 'SerializedScriptValueFactory::instance().create({v8_value}, 0, 0, exceptionState, {isolate})',
     'ScriptValue': 'ScriptValue(ScriptState::current({isolate}), {v8_value})',
+    'SmallTypedArray': '{v8_value}->IsArrayBufferView() ? {variable_name} = std::make_pair(alloca(v8::ArrayBufferView::Cast(*{v8_value})->ByteLength()), v8::ArrayBufferView::Cast(*{v8_value})->ByteLength()), v8::ArrayBufferView::Cast(*{v8_value})->CopyContents({variable_name}.first, {variable_name}.second), {variable_name} : std::make_pair(nullptr, 0)',

[Ken Russell (switch to Gerrit), 2015/04/14 01:40:26]

Is there any way to split this up into multiple expressions to make it more
readable and maintainable?

[Jens Widell, 2015/04/14 09:18:18]

I think we should make a helper function out of it, if we end up with this
approach. We have such helpers (V8XXX::toImpl() typically) for most object
types.

     'Window': 'toDOMWindow({isolate}, {v8_value})',
     'XPathNSResolver': 'toXPathNSResolver({isolate}, {v8_value})',
 }
 
 
 def v8_conversion_needs_exception_state(idl_type):
     return (idl_type.is_numeric_type or
             idl_type.is_enum or
             idl_type.is_dictionary or
             idl_type.name in ('ByteString', 'Dictionary', 'USVString', 'SerializedScriptValue'))
 
 IdlType.v8_conversion_needs_exception_state = property(v8_conversion_needs_exception_state)
 IdlArrayOrSequenceType.v8_conversion_needs_exception_state = True
 IdlUnionType.v8_conversion_needs_exception_state = True
 
 
 TRIVIAL_CONVERSIONS = frozenset([
     'any',
     'boolean',
     'Date',
     'Dictionary',
     'NodeFilter',
+    'SmallTypedArray',
     'XPathNSResolver',
     'Promise'
 ])
 
 
 def v8_conversion_is_trivial(idl_type):
     # The conversion is a simple expression that returns the converted value and
     # cannot raise an exception.
     return (idl_type.base_type in TRIVIAL_CONVERSIONS or
             idl_type.is_wrapper_type)
@@ skipping 443 matching lines @@
     number_of_nullable_member_types_union)
 
 
 def includes_nullable_type_union(idl_type):
     # http://heycam.github.io/webidl/#dfn-includes-a-nullable-type
     return idl_type.number_of_nullable_member_types == 1
 
 IdlTypeBase.includes_nullable_type = False
 IdlNullableType.includes_nullable_type = True
 IdlUnionType.includes_nullable_type = property(includes_nullable_type_union)