Allow collection of DOM objects in minor GC cycles.

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index c4a54a46ed712f3d41dedce76f7d42dcc75a8502..3cd079516bef8ed8b3c9d604cab9b973dd88ed00 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -402,6 +402,16 @@ template <class T> class Persistent : public Handle<T> {
    */
   inline void MarkIndependent();
 
+  /**
+     Marks the reference to this object externally unreachable.
+     Scavenger GC treats this object unreachable if all objects
+     in the object group which this object belongs to are neither
+     strongly reachable nor weakly reachable. This mark is cleared
+     after each scavenger GC.  If this object is not in the new
+     space, this API has no effect.
+   */

[Michael Starzinger, 2012/10/26 14:16:48]

Nit of the day: can we add asterisks to the beginning of each comment line?

[haraken, 2012/10/30 08:51:17]

Done.

+  inline void MarkExternallyUnreachable();
+
   /** Returns true if this handle was previously marked as independent. */
   inline bool IsIndependent() const;
 
@@ -3493,6 +3503,7 @@ class V8EXPORT V8 {
                        WeakReferenceCallback);
   static void ClearWeak(internal::Object** global_handle);
   static void MarkIndependent(internal::Object** global_handle);
+  static void MarkExternallyUnreachable(internal::Object** global_handle);
   static bool IsGlobalIndependent(internal::Object** global_handle);
   static bool IsGlobalNearDeath(internal::Object** global_handle);
   static bool IsGlobalWeak(internal::Object** global_handle);
@@ -4264,6 +4275,11 @@ void Persistent<T>::MarkIndependent() {
 }
 
 template <class T>
+void Persistent<T>::MarkExternallyUnreachable() {
+  V8::MarkExternallyUnreachable(reinterpret_cast<internal::Object**>(**this));
+}
+
+template <class T>
 void Persistent<T>::SetWrapperClassId(uint16_t class_id) {
   V8::SetWrapperClassId(reinterpret_cast<internal::Object**>(**this), class_id);
 }