API functions returning Promises should not throw exceptions.

Source/bindings/scripts/v8_methods.py

Index: Source/bindings/scripts/v8_methods.py
diff --git a/Source/bindings/scripts/v8_methods.py b/Source/bindings/scripts/v8_methods.py
index 94f22f33814e7d2d9871f4d72c35767929293390..f373ebb1b2ca0ecbb23690e9d41cca953b3bfc86 100644
--- a/Source/bindings/scripts/v8_methods.py
+++ b/Source/bindings/scripts/v8_methods.py
@@ -173,6 +173,7 @@ def generate_argument(interface, method, argument, index):
         'v8_set_return_value_for_main_world': v8_set_return_value(interface.name, method, this_cpp_value, for_main_world=True),
         'v8_set_return_value': v8_set_return_value(interface.name, method, this_cpp_value),
         'v8_value_to_local_cpp_value': v8_value_to_local_cpp_value(argument, index),
+        'v8_value_to_local_cpp_value_async': v8_value_to_local_cpp_value_async(argument, index),
     }
 
 
@@ -262,6 +263,25 @@ def v8_value_to_local_cpp_value(argument, index):
                                                 name, index=index)
 
 
+def v8_value_to_local_cpp_value_async(argument, index):

[Nils Barth (inactive), 2014/04/11 10:26:39]

Could you merge this with above, only adding an async=False argument?
The only difference is the macro name in the variadic case, right?
So for the variadic case you can put:
macro = 'TONATIVE_VOID_ASYNC' if async else 'TONATIVE_VOID'
and then have the return expression be something like:
        return '{macro}({vector_type}<{cpp_type}>, {name},
toNativeArguments<{cpp_type}>(info, {index}), info)'.format(
            macro=macro, vector_type=vector_type, cpp_type=idl_type.cpp_type,
            name=name, index=index)

[yhirano, 2014/04/11 10:54:22]

Done. I split the variadic case to another function.

+    extended_attributes = argument.extended_attributes
+    idl_type = argument.idl_type
+    name = argument.name
+    if argument.is_variadic:
+        vector_type = v8_types.cpp_ptr_type('Vector', 'HeapVector', idl_type.gc_type)
+        return 'TONATIVE_VOID_ASYNC({vector_type}<{cpp_type}>, {name}, toNativeArguments<{cpp_type}>(info, {index}), info)'.format(
+            vector_type=vector_type, cpp_type=idl_type.cpp_type, name=name,
+            index=index)
+    # [Default=NullString]
+    if (argument.is_optional and idl_type.name == 'String' and
+        extended_attributes.get('Default') == 'NullString'):
+        v8_value = 'argumentOrNull(info, %s)' % index
+    else:
+        v8_value = 'info[%s]' % index
+    return idl_type.v8_value_to_local_cpp_value(extended_attributes, v8_value,
+                                                name, index=index, async=True)
+
+
 ################################################################################
 # Auxiliary functions
 ################################################################################