IDL: Drop value conversion (V8 -> C++) macros from generated code

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 576 matching lines @@
         add_includes_for_type(native_array_element_type)
     else:
         ref_ptr_type = None
         this_cpp_type = native_array_element_type.cpp_type
         expression_format = 'toImplArray<{cpp_type}>({v8_value}, {index}, {isolate}, exceptionState)'
     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, v8_value=v8_value, isolate=isolate)
     return expression
 
 
 # FIXME: this function should be refactored, as this takes too many flags.
-def v8_value_to_local_cpp_value(idl_type, extended_attributes, v8_value, variable_name=None, index=None, declare_variable=True, isolate='info.GetIsolate()', used_in_private_script=False, return_promise=False, needs_exception_state_for_string=False, restricted_float=False):
+def v8_value_to_local_cpp_value(idl_type, extended_attributes, v8_value, variable_name, index=None, declare_variable=True, isolate='info.GetIsolate()', bailout_return_value=None, use_exception_state=False, restricted_float=False):
     """Returns an expression that converts a V8 value to a C++ value and stores it as a local value."""
 
     this_cpp_type = idl_type.cpp_type_args(extended_attributes=extended_attributes, raw_type=True)
     idl_type = idl_type.preprocessed_type
 
     if idl_type.base_type in ('void', 'object', 'EventHandler', 'EventListener'):
         return '/* no V8 -> C++ conversion for IDL type: %s */' % idl_type.name
 
     cpp_value = v8_value_to_cpp_value(idl_type, extended_attributes, v8_value, variable_name, index, isolate, restricted_float=restricted_float)
 
-    if idl_type.is_dictionary or idl_type.is_union_type:
-        return 'TONATIVE_VOID_EXCEPTIONSTATE_ARGINTERNAL(%s, exceptionState)' % cpp_value
-
     if idl_type.is_string_type or idl_type.v8_conversion_needs_exception_state:
         # Types that need error handling and use one of a group of (C++) macros
         # to take care of this.
 
-        args = [variable_name, cpp_value]
-
-        if idl_type.v8_conversion_needs_exception_state:
-            macro = 'TONATIVE_DEFAULT_EXCEPTIONSTATE' if used_in_private_script else 'TONATIVE_VOID_EXCEPTIONSTATE'
-        elif return_promise or needs_exception_state_for_string:
-            macro = 'TOSTRING_VOID_EXCEPTIONSTATE'
-        else:
-            macro = 'TOSTRING_DEFAULT' if used_in_private_script else 'TOSTRING_VOID'
-
-        if macro.endswith('_EXCEPTIONSTATE'):
-            args.append('exceptionState')
-
-        if used_in_private_script:
-            args.append('false')
-
-        suffix = ''
-
-        if return_promise:
-            suffix += '_PROMISE'
-            args.append('info')
-            if macro.endswith('_EXCEPTIONSTATE'):
-                args.append('ScriptState::current(%s)' % isolate)
+        arguments = []
 
         if declare_variable:
-            args.insert(0, this_cpp_type)
+            macro = 'TONATIVE_DECLARE'
+            arguments.extend([this_cpp_type, variable_name])
         else:
-            suffix += '_INTERNAL'
+            macro = 'TONATIVE_CONVERT'
 
-        return '%s(%s)' % (macro + suffix, ', '.join(args))
+        if idl_type.is_dictionary or idl_type.is_union_type:
+            arguments.append(cpp_value)
+            if not use_exception_state:

[bashi, 2015/02/23 23:44:06]

When could |use_exception_state| be False for dictionary and union types?

[Jens Widell, 2015/02/24 07:31:43]

(Sorry about the poor documentation.)

Here, 'idl_type' talks about the thing we're converting, and
'use_exception_state' talks about the context in which the conversion code
executes.

Specifically, use_exception_state=True means "report exception (only) in the
ExceptionState" while use_exception_state=False means "throw exceptions to V8".

When converting the members of dictionaries and unions, use_exception_state is
true, and when converting arguments to methods it is false (unless the method
returns a promise.)

+                bailout_return_value = 'exceptionState.throwException()'
+        elif idl_type.v8_conversion_needs_exception_state:
+            if use_exception_state:
+                helper = 'convertAndCheck'
+            else:
+                helper = 'convertAndThrow'
+            arguments.append('%s(%s = %s, exceptionState)' % (helper, variable_name, cpp_value))
+        else:  # idl_type.is_string_type
+            if use_exception_state:
+                arguments.append('(%s = %s).prepare(exceptionState)' % (variable_name, v8_value))
+            else:
+                arguments.append('(%s = %s).prepare()' % (variable_name, v8_value))
+
+        if bailout_return_value:
+            arguments.append('return ' + bailout_return_value)
+        else:
+            arguments.append('return')
+
+        return '%s(%s)' % (macro, ', '.join(arguments))
 
     # Types that don't need error handling, and simply assign a value to the
     # local variable.
 
     if not idl_type.v8_conversion_is_trivial:
         raise Exception('unclassified V8 -> C++ conversion for IDL type: %s' % idl_type.name)
 
     assignment = '%s = %s' % (variable_name, cpp_value)
     if declare_variable:
         return '%s %s' % (this_cpp_type, assignment)
@@ skipping 312 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)