[CachedAccessor] for window.document.

third_party/WebKit/Source/bindings/templates/attributes.cpp.tmpl

 {% from 'utilities.cpp.tmpl' import declare_enum_validation_variable, v8_value_to_local_cpp_value %}
 
 {##############################################################################}
 {% macro attribute_getter(attribute, world_suffix) %}
 static void {{attribute.name}}AttributeGetter{{world_suffix}}(
 {%- if attribute.is_data_type_property %}
 const v8::PropertyCallbackInfo<v8::Value>& info
 {%- else %}
 const v8::FunctionCallbackInfo<v8::Value>& info
 {%- endif %})
@@ skipping 218 matching lines @@
     {% if attribute.has_custom_getter %}
     {{v8_class}}::{{attribute.name}}AttributeGetterCustom(info);
     {% else %}
     {{cpp_class_or_partial}}V8Internal::{{attribute.name}}AttributeGetter{{world_suffix}}(info);
     {% endif %}
 }
 {% endmacro %}
 
 
 {##############################################################################}
+{% macro attribute_cache_property_callback(attribute) %}
+static v8::Local<v8::Private> {{attribute.name}}CachedAccessorCallback(v8::Isolate* isolate)

[haraken, 2016/10/24 12:55:43]

I'm just curious, but when is the CachedAccessorCallback called? Is it called
back only at the first time the accessor is accessed? Or is it called back every
time the accessor is accessed?

+{
+    return V8PrivateProperty::get{{attribute.cached_accessor_name}}(isolate).getPrivate();
+}
+{% endmacro %}
+
+
+{##############################################################################}
 {% macro constructor_getter_callback(attribute, world_suffix) %}
 void {{attribute.name}}ConstructorGetterCallback{{world_suffix}}(v8::Local<v8::Name> property, const v8::PropertyCallbackInfo<v8::Value>& info)
 {
     {% if attribute.deprecate_as %}
     Deprecation::countDeprecationIfNotPrivateScript(info.GetIsolate(), currentExecutionContext(info.GetIsolate()), UseCounter::{{attribute.deprecate_as}});
     {% endif %}
 
     {% if attribute.measure_as %}
     UseCounter::countIfNotPrivateScript(info.GetIsolate(), currentExecutionContext(info.GetIsolate()), UseCounter::{{attribute.measure_as('ConstructorGetter')}});
     {% endif %}
@@ skipping 255 matching lines @@
                         ' | '.join(attribute.access_control_list) %}
 {% else %}
 {% set access_control = 'v8::DEFAULT' %}
 {% endif %}
 {% set property_attribute = 'static_cast<v8::PropertyAttribute>(%s)' %
                             ' | '.join(attribute.property_attributes) %}
 {% set only_exposed_to_private_script =
        'V8DOMConfiguration::OnlyExposedToPrivateScript'
        if attribute.only_exposed_to_private_script else
        'V8DOMConfiguration::ExposedToAllScripts' %}
+{% set cached_accessor_callback =
+       '%sV8Internal::%sCachedAccessorCallback' % (cpp_class_or_partial, attribute.name)
+       if attribute.is_cached_accessor else
+       'nullptr' %}
 {% set holder_check = 'V8DOMConfiguration::DoNotCheckHolder'
        if attribute.is_lenient_this else 'V8DOMConfiguration::CheckHolder' %}
 {% set attribute_configuration_list = [
        '"%s"' % attribute.name,
        getter_callback,
        setter_callback,
        getter_callback_for_main_world,
        setter_callback_for_main_world,
+       cached_accessor_callback,
        wrapper_type_info,
        access_control,
        property_attribute,
        only_exposed_to_private_script,
        property_location(attribute),
        holder_check,
    ] %}
 {{'{'}}{{attribute_configuration_list | join(', ')}}{{'}'}}
 {%- endmacro %}