[gin] Introduce Wrappable::GetObjectTemplate

gin/wrappable.h

Index: gin/wrappable.h
diff --git a/gin/wrappable.h b/gin/wrappable.h
index 755707166bb3c39fa19e4365eda69239d860f07c..649c5ff601a5e2527585c6f8c4af08f3a1a9bcd1 100644
--- a/gin/wrappable.h
+++ b/gin/wrappable.h
@@ -27,11 +27,23 @@ GIN_EXPORT void* FromV8Impl(v8::Isolate* isolate,
 // USAGE:
 // // my_class.h
 // class MyClass : Wrappable<MyClass> {
+//  public:
+//   static WrapperInfo kWrapperInfo;
+//
+//  private:
+//   friend class Wrappable<MyClass>;
+//   static v8::Local<v8::ObjectTemplate> GetObjectTemplate(

[Aaron Boodman, 2013/12/16 16:44:26]

It's ok for this to be public now (I think before what was bothering me was that
the responsibility for calling it was with the user).

[Aaron Boodman, 2013/12/16 16:50:35]

Some classes don't want to have any methods or properties on the JS object --
they just use the JS wrapper for lifetime management.

For those cases it would be nice to have a default implementation of
GetObjectTemplate(). Can this be achieved without making GetObjectTemplate()
virtual by having an impl in WrapperBase? I forget how resolution would work in
that case.

[jochen (gone - plz use gerrit), 2013/12/17 14:32:31]

Done.

+//       v8::Isolate* isolate);
 //   ...
 // };
 //
 // // my_class.cc
-// INIT_WRAPABLE(MyClass);
+// WrapperInfo MyClass::kWrapperInfo = { kEmbedderNativeGin };
+//
+// v8::Local<v8::ObjectTemplate> MyClass::GetObjectTemplate(
+//     v8::Isolate* isolate) {
+//   return ObjectTemplateBuilder(isolate, &kWrapperInfo).Build();
+// }
 //
 // Subclasses should also typically have private constructors and expose a
 // static Create function that returns a gin::Handle. Forcing creators through
@@ -46,18 +58,25 @@ class Wrappable;
 // Non-template base class to share code between templates instances.
 class GIN_EXPORT WrappableBase {
  protected:
+  typedef v8::Local<v8::ObjectTemplate> (*TemplateBuilder)(v8::Isolate*);

[Aaron Boodman, 2013/12/16 16:44:26]

Confusing name since we also have ObjectTemplateBuilder. How about just
*GetObjectTemplateFunction

[jochen (gone - plz use gerrit), 2013/12/17 14:32:31]

Done.

+
   WrappableBase();
   virtual ~WrappableBase();
+
   v8::Handle<v8::Object> GetWrapperImpl(v8::Isolate* isolate,
-                                        WrapperInfo* wrapper_info);
-  v8::Handle<v8::Object> CreateWrapper(v8::Isolate* isolate,
-                                       WrapperInfo* wrapper_info);
-  v8::Persistent<v8::Object> wrapper_;  // Weak
+                                        WrapperInfo* wrapper_info,
+                                        TemplateBuilder builder);
 
  private:
   static void WeakCallback(
       const v8::WeakCallbackData<v8::Object, WrappableBase>& data);
 
+  v8::Handle<v8::Object> CreateWrapper(v8::Isolate* isolate,
+                                       WrapperInfo* wrapper_info,
+                                       TemplateBuilder builder);
+
+  v8::Persistent<v8::Object> wrapper_;  // Weak
+
   DISALLOW_COPY_AND_ASSIGN(WrappableBase);
 };
 
@@ -69,7 +88,7 @@ class Wrappable : public WrappableBase {
   // To customize the wrapper created for a subclass, override GetWrapperInfo()
   // instead of overriding this function.
   v8::Handle<v8::Object> GetWrapper(v8::Isolate* isolate) {
-    return GetWrapperImpl(isolate, &T::kWrapperInfo);
+    return GetWrapperImpl(isolate, &T::kWrapperInfo, &T::GetObjectTemplate);
   }
 
  protected: