[CachedAccessor] for window.document.

third_party/WebKit/Source/bindings/core/v8/V8DOMConfiguration.cpp

 /*
  * Copyright (C) 2012 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 105 matching lines @@
             static_cast<v8::PropertyAttribute>(attribute.attribute))
         .ToChecked();
   if (attribute.propertyLocationConfiguration & V8DOMConfiguration::OnInterface)
     NOTREACHED();
 }
 
 template <class FunctionOrTemplate>
 v8::Local<FunctionOrTemplate> createAccessorFunctionOrTemplate(
     v8::Isolate*,
     v8::FunctionCallback,
+    V8DOMConfiguration::CachedAccessorCallback,
     v8::Local<v8::Value> data,
     v8::Local<v8::Signature>,
     int length);
 
 template <>
 v8::Local<v8::FunctionTemplate>
 createAccessorFunctionOrTemplate<v8::FunctionTemplate>(
     v8::Isolate* isolate,
     v8::FunctionCallback callback,
+    V8DOMConfiguration::CachedAccessorCallback cachedAccessorCallback,
     v8::Local<v8::Value> data,
     v8::Local<v8::Signature> signature,
     int length) {
   v8::Local<v8::FunctionTemplate> functionTemplate;
   if (callback) {
-    functionTemplate =
-        v8::FunctionTemplate::New(isolate, callback, data, signature, length);
+    if (cachedAccessorCallback) {
+      functionTemplate = v8::FunctionTemplate::NewWithCache(
+          isolate, callback, cachedAccessorCallback(isolate), data, signature,
+          length);
+    } else {
+      functionTemplate =
+          v8::FunctionTemplate::New(isolate, callback, data, signature, length);
+    }
+
     if (!functionTemplate.IsEmpty()) {
       functionTemplate->RemovePrototype();
       functionTemplate->SetAcceptAnyReceiver(false);
     }
   }
   return functionTemplate;
 }
 
 template <>
 v8::Local<v8::Function> createAccessorFunctionOrTemplate<v8::Function>(
     v8::Isolate* isolate,
     v8::FunctionCallback callback,
+    V8DOMConfiguration::CachedAccessorCallback,
     v8::Local<v8::Value> data,
     v8::Local<v8::Signature> signature,
     int length) {
   if (!callback)
     return v8::Local<v8::Function>();
 
   v8::Local<v8::FunctionTemplate> functionTemplate =
       createAccessorFunctionOrTemplate<v8::FunctionTemplate>(
-          isolate, callback, data, signature, length);
+          isolate, callback, nullptr, data, signature, length);
   if (functionTemplate.IsEmpty())
     return v8::Local<v8::Function>();
 
   v8::Local<v8::Context> context = isolate->GetCurrentContext();
   v8::Local<v8::Function> function;
   if (!functionTemplate->GetFunction(context).ToLocal(&function))
     return v8::Local<v8::Function>();
   return function;
 }
 
 template <class ObjectOrTemplate, class FunctionOrTemplate>
 void installAccessorInternal(
     v8::Isolate* isolate,
     v8::Local<ObjectOrTemplate> instanceOrTemplate,
     v8::Local<ObjectOrTemplate> prototypeOrTemplate,
     v8::Local<FunctionOrTemplate> interfaceOrTemplate,
     v8::Local<v8::Signature> signature,
     const V8DOMConfiguration::AccessorConfiguration& accessor,
     const DOMWrapperWorld& world) {
   if (accessor.exposeConfiguration ==
           V8DOMConfiguration::OnlyExposedToPrivateScript &&
       !world.isPrivateScriptIsolatedWorld())
     return;
 
   v8::Local<v8::Name> name = v8AtomicString(isolate, accessor.name);
   v8::FunctionCallback getterCallback = accessor.getter;
   v8::FunctionCallback setterCallback = accessor.setter;
+  V8DOMConfiguration::CachedAccessorCallback cachedAccessorCallback = nullptr;
   if (world.isMainWorld()) {
     if (accessor.getterForMainWorld)
       getterCallback = accessor.getterForMainWorld;
     if (accessor.setterForMainWorld)
       setterCallback = accessor.setterForMainWorld;
+    cachedAccessorCallback = accessor.cachedAccessorCallback;
   }
+
   // Support [LenientThis] by not specifying the signature.  V8 does not do
   // the type checking against holder if no signature is specified.  Note that
   // info.Holder() passed to callbacks will be *unsafe*.
   if (accessor.holderCheckConfiguration == V8DOMConfiguration::DoNotCheckHolder)
     signature = v8::Local<v8::Signature>();
   v8::Local<v8::Value> data =
       v8::External::New(isolate, const_cast<WrapperTypeInfo*>(accessor.data));
 
   DCHECK(accessor.propertyLocationConfiguration);
   if (accessor.propertyLocationConfiguration &
       (V8DOMConfiguration::OnInstance | V8DOMConfiguration::OnPrototype)) {
     v8::Local<FunctionOrTemplate> getter =
         createAccessorFunctionOrTemplate<FunctionOrTemplate>(
-            isolate, getterCallback, data, signature, 0);
+            isolate, getterCallback, cachedAccessorCallback, data, signature,
+            0);
     v8::Local<FunctionOrTemplate> setter =
         createAccessorFunctionOrTemplate<FunctionOrTemplate>(
-            isolate, setterCallback, data, signature, 1);
+            isolate, setterCallback, nullptr, data, signature, 1);
     if (accessor.propertyLocationConfiguration & V8DOMConfiguration::OnInstance)
       instanceOrTemplate->SetAccessorProperty(
           name, getter, setter,
           static_cast<v8::PropertyAttribute>(accessor.attribute),
           static_cast<v8::AccessControl>(accessor.settings));
     if (accessor.propertyLocationConfiguration &
         V8DOMConfiguration::OnPrototype)
       prototypeOrTemplate->SetAccessorProperty(
           name, getter, setter,
           static_cast<v8::PropertyAttribute>(accessor.attribute),
           static_cast<v8::AccessControl>(accessor.settings));
   }
   if (accessor.propertyLocationConfiguration &
       V8DOMConfiguration::OnInterface) {
     // Attributes installed on the interface object must be static
     // attributes, so no need to specify a signature, i.e. no need to do
     // type check against a holder.
     v8::Local<FunctionOrTemplate> getter =
         createAccessorFunctionOrTemplate<FunctionOrTemplate>(
-            isolate, getterCallback, data, v8::Local<v8::Signature>(), 0);
+            isolate, getterCallback, nullptr, data, v8::Local<v8::Signature>(),

[haraken, 2016/10/20 08:22:23]

nullptr => cachedAccessorCallback?

[vogelheim, 2016/10/20 13:27:59]

Well... not sure. :-/

Since this is case is presently not used (and thus also untested), I'd prefer to
not add the 'cache' here until we actually have a use for. There's no 'hard'
reason, I'm just trying to be careful since there've been several somewhat
subtle bugs with this functionality so far.

Does this make sense?

[haraken, 2016/10/20 13:40:33]

OK, let's keep nullptr here.

+            0);
     v8::Local<FunctionOrTemplate> setter =
         createAccessorFunctionOrTemplate<FunctionOrTemplate>(
-            isolate, setterCallback, data, v8::Local<v8::Signature>(), 1);
+            isolate, setterCallback, nullptr, data, v8::Local<v8::Signature>(),
+            1);
     interfaceOrTemplate->SetAccessorProperty(
         name, getter, setter,
         static_cast<v8::PropertyAttribute>(accessor.attribute),
         static_cast<v8::AccessControl>(accessor.settings));
   }
 }
 
 v8::Local<v8::Primitive> valueForConstant(
     v8::Isolate* isolate,
     const V8DOMConfiguration::ConstantConfiguration& constant) {
@@ skipping 356 matching lines @@
 void V8DOMConfiguration::setClassString(
     v8::Isolate* isolate,
     v8::Local<v8::ObjectTemplate> objectTemplate,
     const char* classString) {
   objectTemplate->Set(
       v8::Symbol::GetToStringTag(isolate), v8AtomicString(isolate, classString),
       static_cast<v8::PropertyAttribute>(v8::ReadOnly | v8::DontEnum));
 }
 
 }  // namespace blink