Generated bindings for IDL callback functions

third_party/WebKit/Source/bindings/scripts/v8_callback_function.py

Index: third_party/WebKit/Source/bindings/scripts/v8_callback_function.py
diff --git a/third_party/WebKit/Source/bindings/scripts/v8_callback_function.py b/third_party/WebKit/Source/bindings/scripts/v8_callback_function.py
new file mode 100644
index 0000000000000000000000000000000000000000..4c1bab5b527e22fa5ecd483c7b6ed3020d91a899
--- /dev/null
+++ b/third_party/WebKit/Source/bindings/scripts/v8_callback_function.py
@@ -0,0 +1,69 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Generate template values for a callback function.
+
+Design doc: http://www.chromium.org/developers/design-documents/idl-compiler
+"""
+
+from v8_globals import includes
+import v8_types
+import v8_utilities
+
+CALLBACK_FUNCTION_H_INCLUDES = frozenset([
+    'bindings/core/v8/ScopedPersistent.h',
+    'platform/heap/Handle.h',
+    'wtf/text/WTFString.h',
+])
+CALLBACK_FUNCTION_CPP_INCLUDES = frozenset([
+    'bindings/core/v8/ScriptState.h',
+    'bindings/core/v8/V8Binding.h',
+    'wtf/Assertions.h',
+])
+
+
+def callback_function_context(callback_function):
+    includes.clear()
+    includes.update(CALLBACK_FUNCTION_CPP_INCLUDES)
+    idl_type = callback_function.idl_type
+    idl_type_str = str(idl_type)
+
+    def member_cpp_type():

[bashi, 2016/09/13 00:35:06]

Why does this need to be a function?

[lkawai, 2016/09/16 05:05:50]

Done.

+        member_cpp_type = idl_type.cpp_type_args(used_in_cpp_sequence=True)
+        if idl_type.impl_should_use_nullable_container:
+            return v8_types.cpp_template_type('Nullable', member_cpp_type)
+        return member_cpp_type
+    context = {
+        'cpp_class': callback_function.name,
+        'v8_class': v8_utilities.v8_class_name(callback_function),
+        'header_includes': set(CALLBACK_FUNCTION_H_INCLUDES),
+        'cpp_includes': set(CALLBACK_FUNCTION_CPP_INCLUDES),
+        'rvalue_cpp_type': idl_type.callback_cpp_type,
+        'idl_type': idl_type_str,
+        'member_cpp_type': member_cpp_type(),

[bashi, 2016/09/13 00:35:06]

It's not clear what 'member_cpp_type' means here. There is no 'member' in the
spec description.

http://heycam.github.io/webidl/#dfn-callback-function

[lkawai, 2016/09/16 05:05:50]

Done.

+        'v8_value_to_local_cpp_value_dict': idl_type.v8_value_to_local_cpp_value(

[bashi, 2016/09/13 00:35:06]

Also, please consider better naming for |v8_value_to_local_cpp_value_dict|

[lkawai, 2016/09/16 05:05:50]

Done.

+            callback_function.extended_attributes, 'currentValue', 'cppValue', bailout_return_value="false"),
+    }
+    context.update(arguments_context(callback_function.arguments, member_cpp_type()))
+    return context
+
+
+def arguments_context(arguments, member_cpp_type):
+    def argument_context(argument):
+        return {
+            'handle': '%sHandle' % argument.name,

[bashi, 2016/09/13 00:35:06]

What does 'handle' mean here?

[lkawai, 2016/09/16 05:05:50]

Done.

+            'cpp_value_to_v8_value': argument.idl_type.cpp_value_to_v8_value(
+                argument.name, isolate='scriptState->isolate()',
+                creation_context='scriptState->context()->Global()'),
+        }
+
+    argument_declarations = ['ScriptState* scriptState', 'ScriptWrappable* scriptWrappable']
+    argument_declarations.extend(
+        '%s %s' % (argument.idl_type.callback_cpp_type, argument.name)
+        for argument in arguments)
+    argument_declarations.append('%s& returnValue' % member_cpp_type)
+    return {
+        'argument_declarations': argument_declarations,
+        'arguments': [argument_context(argument) for argument in arguments],
+    }