Keep a persistent handle for the bindings classes to avoid repeated lookups that involve performing…

Source/bindings/dart/DartDOMWrapper.cpp

Index: Source/bindings/dart/DartDOMWrapper.cpp
diff --git a/Source/bindings/dart/DartDOMWrapper.cpp b/Source/bindings/dart/DartDOMWrapper.cpp
index e26835cefbe34bf556f794747cc6993e17885756..dcaa874fa9f4fab1672441f8cee777647e1ff4d4 100644
--- a/Source/bindings/dart/DartDOMWrapper.cpp
+++ b/Source/bindings/dart/DartDOMWrapper.cpp
@@ -57,23 +57,32 @@ Dart_Handle DartDOMWrapper::instantiateWrapper(const char* className, const char
     return instance;
 }
 
-bool DartDOMWrapper::instanceOf(const char* className, const char* libraryName, Dart_Handle wrapper)
+Dart_Handle DartDOMWrapper::dartClass(const char* className, const char* libraryName, intptr_t index)
 {
-    // FIXME(rmacnak): Cache classes in the corresponding bindings class. Requires persistent handles.
-    Dart_Handle library = DartUtilities::libraryForCurrentIsolate(libraryName);
-    ASSERT(!Dart_IsError(library));
+    Vector<Dart_PersistentHandle> *map = DartDOMData::current()->classHandleCache();
 
-    Dart_Handle type = Dart_GetType(library, Dart_NewStringFromCString(className), 0, 0);
-    ASSERT(!Dart_IsError(type));
-    if (Dart_IsError(type))
-        return false;
-
-    bool isInstanceOf = false;
-    Dart_Handle result = Dart_ObjectIsType(wrapper, type, &isInstanceOf);
-    ASSERT(!Dart_IsError(result));
-    if (Dart_IsError(result))
-        return false;
-    return isInstanceOf;
+    Dart_Handle type;
+    Dart_PersistentHandle persistentType;
+
+    while (map->size() <= index) {
+        map->append(reinterpret_cast<Dart_PersistentHandle>(0));

[siva, 2013/09/10 00:18:50]

Might be more efficient to do:

if (map->size() <= index) {
    intptr_t begin = map->size();
    map->expandCapacity(index + 1);
    for (intptr_t i = begin; i <= index; i++) {
        map->at(i) = reinterpret_cast<Dart_PersistentHandle>(0);
    }
}

[rmacnak, 2013/09/10 20:09:51]

expandCapacity is private, but grow works

+    }
+
+    if (map->at(index)) {
+        persistentType = map->at(index);
+        type = Dart_HandleFromPersistent(persistentType);
+    } else {
+        Dart_Handle library = DartUtilities::libraryForCurrentIsolate(libraryName);
+        ASSERT(!Dart_IsError(library));
+
+        type = Dart_GetType(library, Dart_NewStringFromCString(className), 0, 0);
+        ASSERT(!Dart_IsError(type));
+
+        persistentType = Dart_NewPersistentHandle(type);
+        map->insert(index, persistentType);

[siva, 2013/09/10 00:18:50]

insert here in the implementation of Vector seems to insert this element at the
index moving all elements out by 1. This will cause errors as previously added
elements would get shifted.

I wonder if you are supposed to do
map->at(index) = persistentType;

[rmacnak, 2013/09/10 20:09:51]

map->data()[index] = persistentType seems to do the right thing

+    }
+
+    return type;
 }
 
 Dart_Handle DartDOMWrapper::exceptionCodeToDartException(ExceptionCode exceptionCode)