bindings: Reduces the binary size by reducing # of callback functions.

Source/bindings/templates/interface_base.cpp

 // Copyright 2014 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.
 
 // This file has been auto-generated by {{code_generator}}. DO NOT MODIFY!
 
 #include "config.h"
 {% filter conditional(conditional_string) %}
 #include "{{v8_class_or_partial}}.h"
 
 {% for filename in cpp_includes if filename != '%s.h' % cpp_class_or_partial %}
 #include "{{filename}}"
 {% endfor %}
 
 namespace blink {
 {% set to_active_dom_object = '%s::toActiveDOMObject' % v8_class
                               if is_active_dom_object else '0' %}
 {% set visit_dom_wrapper = '%s::visitDOMWrapper' % v8_class
                            if has_visit_dom_wrapper else '0' %}
 {% set parent_wrapper_type_info = '&V8%s::wrapperTypeInfo' % parent_interface
                                   if parent_interface else '0' %}
 {% set wrapper_type_prototype = 'WrapperTypeExceptionPrototype' if is_exception else
                                 'WrapperTypeObjectPrototype' %}
 {% set dom_template = '%s::domTemplate' % v8_class if not is_array_buffer_or_view else '0' %}
 
 {% set wrapper_type_info_const = '' if has_partial_interface else 'const ' %}
 {% if not is_partial %}
-{{wrapper_type_info_const}}WrapperTypeInfo {{v8_class}}::wrapperTypeInfo = { gin::kEmbedderBlink, {{dom_template}}, {{v8_class}}::refObject, {{v8_class}}::derefObject, {{v8_class}}::trace, {{to_active_dom_object}}, {{visit_dom_wrapper}}, {{v8_class}}::installConditionallyEnabledMethods, {{v8_class}}::installConditionallyEnabledProperties, {{parent_wrapper_type_info}}, WrapperTypeInfo::{{wrapper_type_prototype}}, WrapperTypeInfo::{{wrapper_class_id}}, WrapperTypeInfo::{{event_target_inheritance}}, WrapperTypeInfo::{{lifetime}}, WrapperTypeInfo::{{gc_type}} };
+{{wrapper_type_info_const}}WrapperTypeInfo {{v8_class}}::wrapperTypeInfo = { gin::kEmbedderBlink, {{dom_template}}, {{v8_class}}::refObject, {{v8_class}}::derefObject, {{v8_class}}::trace, {{to_active_dom_object}}, {{visit_dom_wrapper}}, {{v8_class}}::installConditionallyEnabledMethods, {{v8_class}}::installConditionallyEnabledProperties, "{{interface_name}}", {{parent_wrapper_type_info}}, WrapperTypeInfo::{{wrapper_type_prototype}}, WrapperTypeInfo::{{wrapper_class_id}}, WrapperTypeInfo::{{event_target_inheritance}}, WrapperTypeInfo::{{lifetime}}, WrapperTypeInfo::{{gc_type}} };
 
 // This static member must be declared by DEFINE_WRAPPERTYPEINFO in {{cpp_class}}.h.
 // For details, see the comment of DEFINE_WRAPPERTYPEINFO in
 // bindings/core/v8/ScriptWrappable.h.
 {% if is_typed_array_type %}
 template<>
 {% endif %}
 const WrapperTypeInfo& {{cpp_class}}::s_wrapperTypeInfo = {{v8_class}}::wrapperTypeInfo;
 
 {% endif %}
@@ skipping 23 matching lines @@
     ExceptionState exceptionState(ExceptionState::SetterContext, *attributeName, "{{interface_name}}", info.Holder(), info.GetIsolate());
     if (!BindingSecurity::shouldAllowAccessToFrame(info.GetIsolate(), impl->frame(), exceptionState)) {
         exceptionState.throwIfNeeded();
         return;
     }
     {% endif %}
     ASSERT(info.This()->IsObject());
     v8::Local<v8::Object>::Cast(info.This())->ForceSet(name, v8Value);
 }
 
+{% for attribute in attributes
+       if (attribute.constructor_type and
+           attribute.name == attribute.constructor_type and
+           not attribute.is_expose_js_accessors) %}
+{% if loop.first %}

[haraken, 2015/03/17 00:06:07]

Instead of using loop.first, can we introduce
has_constructor_attribute_setter_for_properties? (We normally introduce has_xxx
variables like this.)

[Yuki, 2015/03/17 08:35:19]

Done.

+static void {{cpp_class}}ConstructorAttributeSetterCallbackAsProperty(v8::Local<v8::String>, v8::Local<v8::Value> v8Value, const v8::PropertyCallbackInfo<void>& info)

[haraken, 2015/03/17 00:06:07]

I'm just curious, but how many constructor attributes still need the
PropertyCallbackInfo version?

[Yuki, 2015/03/17 08:35:19]

We've not yet moved any of constructor attribute to prototype chains.  I've
removed accessor version in this CL to make it look simple.

+{
+    TRACE_EVENT_SET_SAMPLING_STATE("blink", "DOMSetter");
+    do {

[haraken, 2015/03/17 00:06:08]

What is the do...while for?

[Yuki, 2015/03/17 08:35:19]

Added a comment.  It's for use of 'break'.
We need to call TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8Execution") at the end.

+        v8::Local<v8::Value> data = info.Data();

[haraken, 2015/03/17 00:06:08]

Not related to your CL, we want to deprecate info.Data(). It would be great if
there is a way to remove info.Data() from the constructor attribute setter.

[Yuki, 2015/03/17 08:35:19]

We could use "hidden value" instead of info.Data(), but it doesn't help much
since hidden values are also discouraged...  I'll keep it in mind.

+        ASSERT(data->IsExternal());
+        V8PerContextData* perContextData = V8PerContextData::from(info.Holder()->CreationContext());
+        if (!perContextData)
+            break;
+        const WrapperTypeInfo* wrapperTypeInfo = WrapperTypeInfo::unwrap(data);
+        if (!wrapperTypeInfo)
+            break;
+        {{cpp_class}}ForceSetAttributeOnThis(v8String(info.GetIsolate(), wrapperTypeInfo->interfaceName), v8Value, info);

[haraken, 2015/03/17 00:06:07]

Not related to your CL, I want to understand why this is ForceSet (which is
discouraged) instead of Set. Can we change the ForceSet to Set and see what
tests fail?

[Yuki, 2015/03/17 08:35:19]

My understanding is:
  Set = regular assignment, which means named/indexed properties are supported.
  ForceSet = bypass interceptors such as named/indexed properties.

We shouldn't use regular Set inside a setter callback, which may cause an
infinite loop.  Since we know 1) the attribute is a replaceable attribute or
constructor attribute, and 2) V8 (JS) found this is the proper setter callback,
thus we should simply set the value without looking for a setter again.

+    } while (false);
+    TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8Execution");
+}
+
+{% endif %}
+{% endfor %}
+{% for attribute in attributes
+       if (attribute.constructor_type and
+           attribute.name == attribute.constructor_type and
+           attribute.is_expose_js_accessors) %}
+{% if loop.first %}

[haraken, 2015/03/17 00:06:08]

Ditto. I'd prefer has_constructor_attribute_setter_for_accessors.

[Yuki, 2015/03/17 08:35:19]

Done.

+static void {{cpp_class}}ConstructorAttributeSetterCallbackAsAccessor(const v8::FunctionCallbackInfo<v8::Value>& info)
+{
+    TRACE_EVENT_SET_SAMPLING_STATE("blink", "DOMSetter");
+    do {

[haraken, 2015/03/17 00:06:07]

What is the do...while for?

[Yuki, 2015/03/17 08:35:19]

Done.

+        v8::Local<v8::Value> v8Value = info[0];
+        v8::Local<v8::Value> data = info.Data();
+        ASSERT(data->IsExternal());
+        V8PerContextData* perContextData = V8PerContextData::from(info.Holder()->CreationContext());
+        if (!perContextData)
+            break;
+        const WrapperTypeInfo* wrapperTypeInfo = WrapperTypeInfo::unwrap(data);
+        if (!wrapperTypeInfo)
+            break;
+        {{cpp_class}}ForceSetAttributeOnThis(v8String(info.GetIsolate(), wrapperTypeInfo->interfaceName), v8Value, info);
+    } while (false);
+    TRACE_EVENT_SET_SAMPLING_STATE("v8", "V8Execution");
+}
+
+{% endif %}
+{% endfor %}
 {% endif %}
 {% endblock %}
 {##############################################################################}
 {% from 'attributes.cpp' import constructor_getter_callback,
        attribute_getter, attribute_getter_callback,
        attribute_setter, attribute_setter_callback,
        attribute_getter_implemented_in_private_script,
        attribute_setter_implemented_in_private_script
        with context %}
 {% for attribute in attributes if attribute.should_be_exposed_to_script %}
 {% for world_suffix in attribute.world_suffixes %}
 {% if not attribute.constructor_type %}
 {% if not attribute.has_custom_getter %}
 {{attribute_getter(attribute, world_suffix)}}
 {% endif %}
 {{attribute_getter_callback(attribute, world_suffix)}}
 {% endif %}
 {% if attribute.has_setter %}
-{% if not attribute.has_custom_setter %}
+{% if not (attribute.has_custom_setter or
+           (attribute.constructor_type and attribute.name == attribute.constructor_type)) %}

[haraken, 2015/03/17 00:06:08]

Maybe I'm wrong, but can we avoid introducing the 'attribute.name ==
attribute.constructor_type' check by storing a "proper" interface name (e.g., a
"WebKit"-prefixed name) on wrapperTypeInfo->interfaceName?

[Yuki, 2015/03/17 08:35:19]

No, we cannot.  At least there is case that 1) the proper interface name is
unprefixed name, and 2) we have both of prefixed and unprefixed constructor
attributes.

For example, we have
  "WebKitTransitionEvent" attribute to create a TransitionEvent, and
  "TransitionEvent" attribute, too, to create a TransitionEvent.

It's better for compatibility.

 {{attribute_setter(attribute, world_suffix)}}
 {% endif %}
+{% if not (attribute.constructor_type and attribute.name == attribute.constructor_type) %}
 {{attribute_setter_callback(attribute, world_suffix)}}
 {% endif %}
+{% endif %}
 {% endfor %}
 {% endfor %}
 {##############################################################################}
 {% for attribute in attributes if attribute.needs_constructor_getter_callback %}
 {% for world_suffix in attribute.world_suffixes %}
 {{constructor_getter_callback(attribute, world_suffix)}}
 {% endfor %}
 {% endfor %}
 {##############################################################################}
 {% block security_check_functions %}
@@ skipping 372 matching lines @@
 {% endfor %}
 {% for attribute in attributes if attribute.is_implemented_in_private_script %}
 {{attribute_getter_implemented_in_private_script(attribute)}}
 {% if attribute.has_setter %}
 {{attribute_setter_implemented_in_private_script(attribute)}}
 {% endif %}
 {% endfor %}
 {% block partial_interface %}{% endblock %}
 } // namespace blink
 {% endfilter %}