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

Source/bindings/dart/DartDOMWrapper.cpp

 // Copyright 2011, 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:
 //
 //    * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //    * Redistributions in binary form must reproduce the above
@@ skipping 39 matching lines @@
 
     Dart_Handle type = Dart_GetType(library, Dart_NewStringFromCString(className), 0, 0);
     ASSERT(!Dart_IsError(type));
 
     Dart_Handle instance = Dart_Allocate(type);
     ASSERT(!Dart_IsError(instance));
 
     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;
+    Dart_Handle type;
+    Dart_PersistentHandle persistentType;
 
-    bool isInstanceOf = false;
-    Dart_Handle result = Dart_ObjectIsType(wrapper, type, &isInstanceOf);
-    ASSERT(!Dart_IsError(result));
-    if (Dart_IsError(result))
-        return false;
-    return isInstanceOf;
+    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)
 {
     ASSERT(exceptionCode > 0);
 
     // FIXME: Get a better exception message here.
     RefPtr<DOMException> domException = DOMException::create(exceptionCode, "Internal Dartium Exception");
 
     return DartDOMException::toDart(domException);
 }
 
 Dart_Handle DartDOMWrapper::exceptionCodeToDartException(DartExceptionState& exceptionState)
 {
     return exceptionCodeToDartException(exceptionState.code());
 }
 
 }