Refactor callback emission.

lib/dom/scripts/systemnative.py

 #!/usr/bin/python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """This module provides shared functionality for the systems to generate
 native binding from the IDL database."""
 
 import emitter
 import os
@@ skipping 227 matching lines @@
 
     ext_attrs = self._interface.ext_attrs
 
     if 'CustomConstructor' in ext_attrs:
       # We have a custom implementation for it.
       self._cpp_declarations_emitter.Emit(
           '\n'
           'void constructorCallback(Dart_NativeArguments);\n')
       return
 
-    raises_dom_exceptions = 'ConstructorRaisesException' in ext_attrs
-    raises_exceptions = raises_dom_exceptions or len(constructor_info.idl_args) > 0
-    arguments = []
-    parameter_definitions_emitter = emitter.Emitter()
     create_function = 'create'
     if 'NamedConstructor' in ext_attrs:
-      raises_exceptions = True
-      self._cpp_impl_includes.add('"DOMWindow.h"')
-      parameter_definitions_emitter.Emit(
-            '        DOMWindow* domWindow = DartUtilities::domWindowForCurrentIsolate();\n'
-            '        if (!domWindow) {\n'
-            '            exception = Dart_NewString("Failed to fetch domWindow");\n'
-            '            goto fail;\n'
-            '        }\n'
-            '        Document* document = domWindow->document();\n')
-      arguments.append('document')
       create_function = 'createForJSConstructor'
-    if 'CallWith' in ext_attrs:
-      call_with = ext_attrs['CallWith']
-      if call_with == 'ScriptExecutionContext':
-        raises_exceptions = True
-        parameter_definitions_emitter.Emit(
-            '        ScriptExecutionContext* context = DartUtilities::scriptExecutionContext();\n'
-            '        if (!context) {\n'
-            '            exception = Dart_NewString("Failed to create an object");\n'
-            '            goto fail;\n'
-            '        }\n')
-        arguments.append('context')
-      else:
-        raise Exception('Unsupported CallWith=%s attribute' % call_with)
-
-    # Process constructor arguments.
-    for (i, argument) in enumerate(constructor_info.idl_args):
-      argument_expression = self._GenerateToNative(
-          parameter_definitions_emitter, argument, i)
-      arguments.append(argument_expression)
-
     function_expression = '%s::%s' % (self._interface_type_info.native_type(), create_function)
-    invocation = self._GenerateWebCoreInvocation(function_expression, arguments,
-        self._interface.id, ext_attrs, raises_dom_exceptions)
-
-    runtime_check = None
-    database = self._database
-    assert (not (
-      'synthesizedV8EnabledPerContext' in ext_attrs and
-      'synthesizedV8EnabledAtRuntime' in ext_attrs))
-    if 'synthesizedV8EnabledPerContext' in ext_attrs:
-      raises_exceptions = True
-      self._cpp_impl_includes.add('"ContextFeatures.h"')
-      self._cpp_impl_includes.add('"DOMWindow.h"')
-      runtime_check = emitter.Format(
-          '        if (!ContextFeatures::$(FEATURE)Enabled(DartUtilities::domWindowForCurrentIsolate()->document())) {\n'
-          '            exception = Dart_NewString("Feature $FEATURE is not enabled");\n'
-          '            goto fail;\n'
-          '        }',
-          FEATURE=ext_attrs['synthesizedV8EnabledPerContext'])
-
-    if 'synthesizedV8EnabledAtRuntime' in ext_attrs:
-      raises_exceptions = True
-      self._cpp_impl_includes.add('"RuntimeEnabledFeatures.h"')
-      runtime_check = emitter.Format(
-          '        if (!RuntimeEnabledFeatures::$(FEATURE)Enabled()) {\n'
-          '            exception = Dart_NewString("Feature $FEATURE is not enabled");\n'
-          '            goto fail;\n'
-          '        }',
-          FEATURE=_ToWebKitName(ext_attrs['synthesizedV8EnabledAtRuntime']))
-
-    self._GenerateNativeCallback(callback_name='constructorCallback',
-        parameter_definitions=parameter_definitions_emitter.Fragments(),
-        needs_receiver=False, invocation=invocation,
-        raises_exceptions=raises_exceptions,
-        runtime_check=runtime_check,
-        requires_v8_scope=self._RequiresV8Scope(ext_attrs, constructor_info.idl_args))
-
+    self._GenerateNativeCallback(
+        'constructorCallback',
+        False,
+        function_expression,
+        self._interface,
+        constructor_info.idl_args,
+        self._interface.id,
+        'ConstructorRaisesException' in ext_attrs)
 
   def _ImplClassName(self, interface_name):
     return '_%sImpl' % interface_name
 
   def _BaseClassName(self):
     root_class = 'NativeFieldWrapperClass1'
 
     if not self._interface.parents:
       return root_class
 
@@ skipping 100 matching lines @@
         INTERFACE=self._interface.id,
         WEBCORE_INCLUDES=webcore_includes,
         WEBCORE_CLASS_NAME=self._interface_type_info.native_type(),
         DECLARATIONS=self._cpp_declarations_emitter.Fragments(),
         IS_NODE=TypeCheckHelper(is_node_test),
         IS_ACTIVE=TypeCheckHelper(is_active_test),
         IS_EVENT_TARGET=TypeCheckHelper(is_event_target_test),
         TO_NATIVE=to_native_emitter.Fragments(),
         TO_DART=to_dart_emitter.Fragments())
 
-  def _GenerateCallWithHandling(self, node, parameter_definitions_emitter, arguments):
-    if 'CallWith' not in node.ext_attrs:
-      return False
-
-    call_with = node.ext_attrs['CallWith']
-    if call_with == 'ScriptExecutionContext':
-      parameter_definitions_emitter.Emit(
-          '\n'
-          '        ScriptExecutionContext* context = DartUtilities::scriptExecutionContext();\n'
-          '        if (!context)\n'
-          '            return;\n')
-      arguments.append('context')
-      return False
-
-    if call_with == 'ScriptArguments|CallStack':
-      self._cpp_impl_includes.add('"ScriptArguments.h"')
-      self._cpp_impl_includes.add('"ScriptCallStack.h"')
-      parameter_definitions_emitter.Emit(
-          '\n'
-          '        Dart_Handle customArgument = Dart_GetNativeArgument(args, $INDEX);\n'
-          '        RefPtr<ScriptArguments> scriptArguments(DartUtilities::createScriptArguments(customArgument, exception));\n'
-          '        if (!scriptArguments)\n'
-          '            goto fail;\n'
-          '        RefPtr<ScriptCallStack> scriptCallStack(DartUtilities::createScriptCallStack());\n'
-          '        if (!scriptCallStack->size())\n'
-          '            return;\n',
-          INDEX=len(node.arguments))
-      arguments.extend(['scriptArguments', 'scriptCallStack'])
-      return True
-
-    return False
-
   def AddAttribute(self, attribute, html_name, read_only):
     if 'CheckSecurityForNode' in attribute.ext_attrs:
       # FIXME: exclude from interface as well.
       return
 
     self._AddGetter(attribute, html_name)
     if not read_only:
       self._AddSetter(attribute, html_name)
 
   def _AddGetter(self, attr, html_name):
     type_info = self._TypeInfo(attr.type.id)
     dart_declaration = '%s get %s()' % (self._DartType(attr.type.id), html_name)
     is_custom = 'Custom' in attr.ext_attrs or 'CustomGetter' in attr.ext_attrs
     cpp_callback_name = self._GenerateNativeBinding(attr.id, 1,
         dart_declaration, 'Getter', is_custom)
     if is_custom:
       return
 
-    arguments = []
-    parameter_definitions_emitter = emitter.Emitter()
-    raises_exceptions = self._GenerateCallWithHandling(
-        attr, parameter_definitions_emitter, arguments)
-    raises_exceptions = raises_exceptions or attr.get_raises
-
     if 'Reflect' in attr.ext_attrs:
       webcore_function_name = self._TypeInfo(attr.type.id).webcore_getter_name()
       if 'URL' in attr.ext_attrs:
         if 'NonEmpty' in attr.ext_attrs:
           webcore_function_name = 'getNonEmptyURLAttribute'
         else:
           webcore_function_name = 'getURLAttribute'
-      arguments.append(self._GenerateWebCoreReflectionAttributeName(attr))
     else:
       if attr.id == 'operator':
         webcore_function_name = '_operator'
       elif attr.id == 'target' and attr.type.id == 'SVGAnimatedString':
         webcore_function_name = 'svgTarget'
       else:
         webcore_function_name = _ToWebKitName(attr.id)
       if attr.type.id.startswith('SVGAnimated'):
         webcore_function_name += 'Animated'
 
     function_expression = self._GenerateWebCoreFunctionExpression(webcore_function_name, attr)
-    invocation = self._GenerateWebCoreInvocation(function_expression,
-        arguments, attr.type.id, attr.ext_attrs, attr.get_raises)
-    self._GenerateNativeCallback(cpp_callback_name, parameter_definitions_emitter.Fragments(),
-        True, invocation, raises_exceptions=raises_exceptions,
-        runtime_check=None,
-        requires_v8_scope=self._RequiresV8Scope(attr.ext_attrs, []))
+    self._GenerateNativeCallback(
+        cpp_callback_name,
+        True,
+        function_expression,
+        attr,
+        [],
+        attr.type.id,
+        attr.get_raises)
 
   def _AddSetter(self, attr, html_name):
     type_info = self._TypeInfo(attr.type.id)
     dart_declaration = 'void set %s(%s)' % (html_name, self._DartType(attr.type.id))
     is_custom = set(['Custom', 'CustomSetter', 'V8CustomSetter']) & set(attr.ext_attrs)
     cpp_callback_name = self._GenerateNativeBinding(attr.id, 2,
         dart_declaration, 'Setter', is_custom)
     if is_custom:
       return
 
-    arguments = []
-    parameter_definitions_emitter = emitter.Emitter()
-    self._GenerateCallWithHandling(attr, parameter_definitions_emitter, arguments)
-
     if 'Reflect' in attr.ext_attrs:
       webcore_function_name = self._TypeInfo(attr.type.id).webcore_setter_name()
-      arguments.append(self._GenerateWebCoreReflectionAttributeName(attr))
     else:
       webcore_function_name = re.sub(r'^(xml(?=[A-Z])|\w)',
                                      lambda s: s.group(1).upper(),
                                      attr.id)
       webcore_function_name = 'set%s' % webcore_function_name
       if attr.type.id.startswith('SVGAnimated'):
         webcore_function_name += 'Animated'
 
-    argument_expression = self._GenerateToNative(
-        parameter_definitions_emitter, attr, 1, argument_name='value')
-    arguments.append(argument_expression)
-
-    parameter_definitions = parameter_definitions_emitter.Fragments()
     function_expression = self._GenerateWebCoreFunctionExpression(webcore_function_name, attr)
-    invocation = self._GenerateWebCoreInvocation(function_expression,
-        arguments, 'void', attr.ext_attrs, attr.set_raises)
-
-    self._GenerateNativeCallback(cpp_callback_name, parameter_definitions_emitter.Fragments(),
-        True, invocation, raises_exceptions=True,
-        runtime_check=None,
-        requires_v8_scope=self._RequiresV8Scope(attr.ext_attrs, [attr]))
+    self._GenerateNativeCallback(
+        cpp_callback_name,
+        True,
+        function_expression,
+        attr,
+        [attr],
+        'void',
+        attr.set_raises)
 
   def AddIndexer(self, element_type):
     """Adds all the methods required to complete implementation of List."""
     # We would like to simply inherit the implementation of everything except
     # get length(), [], and maybe []=.  It is possible to extend from a base
     # array implementation class only when there is no other implementation
     # inheritance.  There might be no implementation inheritance other than
     # DOMBaseWrapper for many classes, but there might be some where the
     # array-ness is introduced by a non-root interface:
     #
@@ skipping 171 matching lines @@
         if _IsArgumentOptionalInWebCore(argument):
           check = '%s === _null' % argument_names[position]
           GenerateCall(operation, position, [check])
       GenerateCall(operation, len(operation.arguments), [])
 
   def SecondaryContext(self, interface):
     pass
 
   def _GenerateOperationNativeCallback(self, operation, arguments, cpp_callback_name):
     webcore_function_name = operation.ext_attrs.get('ImplementedAs', operation.id)
+    function_expression = self._GenerateWebCoreFunctionExpression(webcore_function_name, operation)
+    self._GenerateNativeCallback(
+        cpp_callback_name,
+        not operation.is_static,
+        function_expression,
+        operation,
+        arguments,
+        operation.type.id,
+        operation.raises)
+
+  def _GenerateNativeCallback(self,
+      callback_name,
+      needs_receiver,
+      function_expression,
+      node,
+      arguments,
+      return_type,
+      raises_dom_exception):
+    ext_attrs = node.ext_attrs
+    cpp_arguments = []
+
+    requires_v8_scope = False
+    runtime_check = None
+    raises_exceptions = False
+    requires_script_execution_context = False
+    requires_dom_window = False
+    requires_stack_info = False

[podivilov1, 2012/08/21 10:28:53]

There is too many flags coming from different places. Would be nice to cleanup
this list, e.g. separate flags that affect c++ parameter list from flags
affecting native callback code structure.

[Anton Muhin, 2012/08/21 12:09:49]

Agree.  BTW, please, have a look at the latest version, it looks readable enough
for me, but YMMV.

On 2012/08/21 10:28:53, podivilov1 wrote:

+
+    if raises_dom_exception or arguments:
+      raises_exceptions = True
+
+    if ext_attrs.get('CallWith') == 'ScriptArguments|CallStack':
+      raises_exceptions = True
+      requires_v8_scope = True
+      requires_stack_info = True
+      self._cpp_impl_includes.add('"ScriptArguments.h"')
+      self._cpp_impl_includes.add('"ScriptCallStack.h"')
+      cpp_arguments = ['scriptArguments', 'scriptCallStack']
+
+    if ext_attrs.get('CallWith') == 'ScriptExecutionContext':
+      raises_exceptions = True
+      requires_script_execution_context = True
+
+    if 'NamedConstructor' in ext_attrs:
+      raises_exceptions = True
+      requires_dom_window = True
+      self._cpp_impl_includes.add('"DOMWindow.h"')
+      cpp_arguments = ['document']
+
+    if 'Reflect' in ext_attrs:
+      cpp_arguments = [self._GenerateWebCoreReflectionAttributeName(node)]
+
+    for argument in arguments:
+      if self._TypeInfo(argument.type.id).requires_v8_scope():
+        requires_v8_scope = True
 
     parameter_definitions_emitter = emitter.Emitter()
-    cpp_arguments = []
-    raises_exceptions = self._GenerateCallWithHandling(
-        operation, parameter_definitions_emitter, cpp_arguments)
-    raises_exceptions = raises_exceptions or len(arguments) > 0 or operation.raises
-
     # Process Dart cpp_arguments.
-    start_index = 1
-    if operation.is_static:
-      start_index = 0
+    start_index = 0
+    if needs_receiver:
+      start_index = 1
     for (i, argument) in enumerate(arguments):
       if (i == len(arguments) - 1 and
           self._interface.id == 'Console' and
           argument.id == 'arg'):
         # FIXME: we are skipping last argument here because it was added in
         # supplemental dart.idl. Cleanup dart.idl and remove this check.
         break
       argument_expression = self._GenerateToNative(
           parameter_definitions_emitter, argument, start_index + i)
       cpp_arguments.append(argument_expression)
 
-    if operation.id in ['addEventListener', 'removeEventListener']:
+    # FIXME: rework in IDLs.
+    if node.id in ['addEventListener', 'removeEventListener']:
       # addEventListener's and removeEventListener's last argument is marked
       # as optional in idl, but is not optional in webcore implementation.
       if len(arguments) == 2:
         cpp_arguments.append('false')
 
-    if self._interface.id == 'CSSStyleDeclaration' and operation.id == 'setProperty':
+    if self._interface.id == 'CSSStyleDeclaration' and node.id == 'setProperty':
       # CSSStyleDeclaration.setProperty priority parameter is optional in Dart
       # idl, but is not optional in webcore implementation.
       if len(arguments) == 2:
         cpp_arguments.append('String()')
 
-    if 'NeedsUserGestureCheck' in operation.ext_attrs:
-      cpp_arguments.append('DartUtilities::processingUserGesture')
+    if 'NeedsUserGestureCheck' in ext_attrs:
+      cpp_arguments.append('DartUtilities::processingUserGesture');

[podivilov1, 2012/08/21 10:28:53]

semicolon :)

[Anton Muhin, 2012/08/21 12:09:49]

Oops.

On 2012/08/21 10:28:53, podivilov1 wrote:

 
-    function_expression = self._GenerateWebCoreFunctionExpression(webcore_function_name, operation)
-    invocation = self._GenerateWebCoreInvocation(function_expression, cpp_arguments,
-        operation.type.id, operation.ext_attrs, operation.raises)
-    self._GenerateNativeCallback(cpp_callback_name,
-        parameter_definitions=parameter_definitions_emitter.Fragments(),
-        needs_receiver=not operation.is_static, invocation=invocation,
-        raises_exceptions=raises_exceptions,
-        runtime_check=None,
-        requires_v8_scope=self._RequiresV8Scope(operation.ext_attrs, arguments))
+    assert (not (
+      'synthesizedV8EnabledPerContext' in ext_attrs and
+      'synthesizedV8EnabledAtRuntime' in ext_attrs))
+    if 'synthesizedV8EnabledPerContext' in ext_attrs:
+      raises_exceptions = True
+      self._cpp_impl_includes.add('"ContextFeatures.h"')
+      self._cpp_impl_includes.add('"DOMWindow.h"')
+      runtime_check = emitter.Format(
+          '        if (!ContextFeatures::$(FEATURE)Enabled(DartUtilities::domWindowForCurrentIsolate()->document())) {\n'
+          '            exception = Dart_NewString("Feature $FEATURE is not enabled");\n'
+          '            goto fail;\n'
+          '        }',
+          FEATURE=ext_attrs['synthesizedV8EnabledPerContext'])
 
-  def _GenerateNativeCallback(self, callback_name, parameter_definitions,
-      needs_receiver, invocation, raises_exceptions, runtime_check,
-      requires_v8_scope):
+    if 'synthesizedV8EnabledAtRuntime' in ext_attrs:
+      raises_exceptions = True
+      self._cpp_impl_includes.add('"RuntimeEnabledFeatures.h"')
+      runtime_check = emitter.Format(
+          '        if (!RuntimeEnabledFeatures::$(FEATURE)Enabled()) {\n'
+          '            exception = Dart_NewString("Feature $FEATURE is not enabled");\n'
+          '            goto fail;\n'
+          '        }',
+          FEATURE=_ToWebKitName(ext_attrs['synthesizedV8EnabledAtRuntime']))
+
+    invocation = self._GenerateWebCoreInvocation(
+        function_expression, cpp_arguments, return_type, ext_attrs, raises_dom_exception)
 
     head_emitter = emitter.Emitter()
 
     if requires_v8_scope:
       head_emitter.Emit(
           '        V8Scope v8scope;\n\n')
 
     if runtime_check:
       head_emitter.Emit(
           '$RUNTIME_CHECK\n',
           RUNTIME_CHECK=runtime_check)
 
+    if requires_script_execution_context:
+      head_emitter.Emit(
+          '        ScriptExecutionContext* context = DartUtilities::scriptExecutionContext();\n'
+          '        if (!context) {\n'
+          '            exception = Dart_NewString("Failed to retrieve a context");\n'
+          '            goto fail;\n'
+          '        }\n\n')
+
+    if requires_dom_window:
+      head_emitter.Emit(
+          '        DOMWindow* domWindow = DartUtilities::domWindowForCurrentIsolate();\n'
+          '        if (!domWindow) {\n'
+          '            exception = Dart_NewString("Failed to fetch domWindow");\n'
+          '            goto fail;\n'
+          '        }\n'
+          '        Document* document = domWindow->document();\n')

[podivilov1, 2012/08/21 10:28:53]

Personally, I don't like splitting c++ parameter definitions generation from
parameter list building. Maybe introduce a builder class as discussed
previously?

[Anton Muhin, 2012/08/21 12:09:49]

I overall agree, but there were some unpleasant changes which make it somewhat
hard to place document/scriptExecution context into the correct place, hence the
split logic.

On 2012/08/21 10:28:53, podivilov1 wrote:

+
     if needs_receiver:
       head_emitter.Emit(
           '        $WEBCORE_CLASS_NAME* receiver = DartDOMWrapper::receiver< $WEBCORE_CLASS_NAME >(args);\n',
           WEBCORE_CLASS_NAME=self._interface_type_info.native_type())
 
+    if requires_stack_info:
+      head_emitter.Emit(
+          '\n'
+          '        Dart_Handle customArgument = Dart_GetNativeArgument(args, $INDEX);\n'
+          '        RefPtr<ScriptArguments> scriptArguments(DartUtilities::createScriptArguments(customArgument, exception));\n'
+          '        if (!scriptArguments)\n'
+          '            goto fail;\n'
+          '        RefPtr<ScriptCallStack> scriptCallStack(DartUtilities::createScriptCallStack());\n'
+          '        if (!scriptCallStack->size())\n'
+          '            return;\n',
+          INDEX=len(arguments))
+
     head_emitter.Emit(
         '$PARAMETE_DEFINITIONS\n',
-        PARAMETE_DEFINITIONS=parameter_definitions)
+        PARAMETE_DEFINITIONS=parameter_definitions_emitter.Fragments())
 
     body = emitter.Format(
         '    {\n'
         '$HEAD'
         '$INVOCATION'
         '        return;\n'
         '    }\n',
         HEAD=head_emitter.Fragments(),
         INVOCATION=invocation)
 
@@ skipping 10 matching lines @@
     self._cpp_definitions_emitter.Emit(
         '\n'
         'static void $CALLBACK_NAME(Dart_NativeArguments args)\n'
         '{\n'
         '    DartApiScope dartApiScope;\n'
         '$BODY'
         '}\n',
         CALLBACK_NAME=callback_name,
         BODY=body)
 
-  def _GenerateToNative(self, emitter, idl_node, index, argument_name=None):
+  def _GenerateToNative(self, emitter, idl_node, index):
     """idl_node is IDLArgument or IDLAttribute."""
     type_info = self._TypeInfo(idl_node.type.id)
     self._cpp_impl_includes |= set(type_info.to_native_includes())
-    argument_name = argument_name or idl_node.id
+    argument_name = idl_node.id
+    # Rename to get rid of conflicts with C++ keywords.
+    if argument_name == 'default':

[podivilov1, 2012/08/21 10:28:53]

This is fragile because it differs from what v8 generator does. Setter argument
name should always be 'value'.

[Anton Muhin, 2012/08/21 12:09:49]

I don't think it's a big problem to be different from v8 here, anything I am
missing?

On 2012/08/21 10:28:53, podivilov1 wrote:

+      argument_name = 'value'
     handle = 'Dart_GetNativeArgument(args, %i)' % index
     argument_expression = type_info.emit_to_native(
         emitter, idl_node, argument_name, handle, self._interface.id)
     return argument_expression
 
-  def _RequiresV8Scope(self, ext_attrs, arguments):
-    if 'CallWith' in ext_attrs and ext_attrs['CallWith'] == 'ScriptArguments|CallStack':
-      return True
-    for argument in arguments:
-      if self._TypeInfo(argument.type.id).requires_v8_scope():
-        return True
-    return False
-
   def _GenerateNativeBinding(self, idl_name, argument_count, dart_declaration,
       native_suffix, is_custom):
     native_binding = '%s_%s_%s' % (self._interface.id, idl_name, native_suffix)
     self._members_emitter.Emit(
         '\n'
         '  $DART_DECLARATION native "$NATIVE_BINDING";\n',
         DART_DECLARATION=dart_declaration, NATIVE_BINDING=native_binding)
 
     cpp_callback_name = '%s%s' % (idl_name, native_suffix)
     self._cpp_resolver_emitter.Emit(
@@ skipping 52 matching lines @@
       invocation_template = emitter.Format(
           '        ExceptionCode ec = 0;\n'
           '$INVOCATION'
           '        if (UNLIKELY(ec)) {\n'
           '            exception = DartDOMWrapper::exceptionCodeToDartException(ec);\n'
           '            goto fail;\n'
           '        }\n',
           INVOCATION=invocation_template)
 
     if 'ImplementedBy' in attributes:
-      # FIXME: rather ugly way to solve the problem.
-      index = 1 if 'ScriptExecutionContext' == attributes.get('CallWith') else 0
-      arguments.insert(index, 'receiver')
+      arguments.insert(0, 'receiver')
       self._cpp_impl_includes.add('"%s.h"' % attributes['ImplementedBy'])
 
+    if attributes.get('CallWith') == 'ScriptExecutionContext':
+      arguments.insert(0, 'context')
+
     return emitter.Format(invocation_template,
         FUNCTION_CALL='%s(%s)' % (function_expression, ', '.join(arguments)))
 
   def _TypeInfo(self, type_name):
     return self._system._type_registry.TypeInfo(type_name)
 
 
 def _GenerateCPPIncludes(includes):
   return ''.join(['#include %s\n' % include for include in sorted(includes)])
 
@@ skipping 11 matching lines @@
 
 def _IsArgumentOptionalInWebCore(argument):
   return IsOptional(argument) and not 'Callback' in argument.ext_attrs
 
 def _ToWebKitName(name):
   name = name[0].lower() + name[1:]
   name = re.sub(r'^(hTML|uRL|jS|xML|xSLT)', lambda s: s.group(1).lower(),
                 name)
   return re.sub(r'^(create|exclusive)', lambda s: 'is' + s.group(1).capitalize(),
                 name)