Make NodeFilter a legacy callback interface.

third_party/WebKit/Source/bindings/scripts/v8_callback_interface.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 17 matching lines @@
 
 """Generate template values for a callback interface.
 
 Extends IdlTypeBase with property |callback_cpp_type|.
 
 Design doc: http://www.chromium.org/developers/design-documents/idl-compiler
 """
 
 from idl_types import IdlTypeBase
 from v8_globals import includes
+from v8_interface import constant_context
 import v8_types
 import v8_utilities
 
 CALLBACK_INTERFACE_H_INCLUDES = frozenset([
     'bindings/core/v8/DOMWrapperWorld.h',
     'bindings/core/v8/ScopedPersistent.h',
 ])
 CALLBACK_INTERFACE_CPP_INCLUDES = frozenset([
     'bindings/core/v8/ScriptController.h',
     'bindings/core/v8/V8BindingForCore.h',
+    'bindings/core/v8/V8DOMConfiguration.h',
     'core/dom/ExecutionContext.h',
     'platform/wtf/Assertions.h',
     'platform/wtf/GetPtr.h',
     'platform/wtf/RefPtr.h',
 ])
 
 
 def cpp_type(idl_type):
     # FIXME: remove this function by making callback types consistent
     # (always use usual v8_types.cpp_type)
     idl_type_name = idl_type.name
     if idl_type_name == 'String':
         return 'const String&'
     if idl_type_name == 'void':
         return 'void'
     # Callbacks use raw pointers, so raw_type=True
     raw_cpp_type = idl_type.cpp_type_args(raw_type=True)
     # Pass containers and dictionaries to callback method by const reference rather than by value
     if raw_cpp_type.startswith(('Vector', 'HeapVector')) or idl_type.is_dictionary:
         return 'const %s&' % raw_cpp_type
     return raw_cpp_type
 
 IdlTypeBase.callback_cpp_type = property(cpp_type)
 
 
 def callback_interface_context(callback_interface, _):
     includes.clear()
     includes.update(CALLBACK_INTERFACE_CPP_INCLUDES)
+    is_legacy = len(callback_interface.constants) > 0
     return {
         'cpp_class': callback_interface.name,
         'v8_class': v8_utilities.v8_class_name(callback_interface),
         'header_includes': set(CALLBACK_INTERFACE_H_INCLUDES),
-        'methods': [method_context(operation)
-                    for operation in callback_interface.operations],
+        'methods': [] if is_legacy else [method_context(operation)

[bashi, 2017/04/27 08:49:49]

nit: We use alphabetical ordering in dicts.

[bashi, 2017/04/27 08:49:49]

Why do we need to set an empty list when |is_legacy| is true?

[tkent, 2017/04/27 09:15:12]

Because method_context() crashes due to unsupported 'unsigned short' return
value in NodeFilter.idl.

[bashi, 2017/04/27 23:12:32]

Could you put the error log here? I'd prefer fixing method_context() rather than
adding a workaround here.

[tkent, 2017/04/28 00:09:43]

Obviously, it's an intentional exception.

def method_context(operation):
    ....
    if idl_type_str not in ['boolean', 'void']:
        raise Exception('We only support callbacks that return boolean or void
values.')

If we add 'unsigned short' here, the method generation part of
callback_interface.cpp.tmpl generates non-buildable cpp files though NodeFilter
doesn't use this code path.

[bashi, 2017/04/28 00:59:09]

I see. Thank you for the explanation. Given that we don't need to use 'methods'
and need extra info like constants for legacy callback interface (IIUC
NodeFilter is the only instance of legacy callback interface), it would make
sense to have legacy_callback_interface_context() instead of modifying
callback_interface_context().

+                                         for operation in callback_interface.operations],
+        'is_legacy': is_legacy,
+        # For legacy callback interface
+        'interface_name': callback_interface.name,
+        'constants': [constant_context(constant, callback_interface)
+                      for constant in callback_interface.constants],
     }
 
 
 def add_includes_for_operation(operation):
     operation.idl_type.add_includes_for_type()
     for argument in operation.arguments:
         argument.idl_type.add_includes_for_type()
 
 
 def method_context(operation):
@@ skipping 29 matching lines @@
         }
 
     argument_declarations = ['ScriptValue thisValue'] if call_with_this_handle else []
     argument_declarations.extend(
         '%s %s' % (argument.idl_type.callback_cpp_type, argument.name)
         for argument in arguments)
     return  {
         'argument_declarations': argument_declarations,
         'arguments': [argument_context(argument) for argument in arguments],
     }