Encapsulate element handling into a class keyed on ElementsKind

src/elements.h

+// Copyright 2011 the V8 project authors. 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
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_ELEMENTS_H_
+#define V8_ELEMENTS_H_
+
+#include "objects.h"
+
+namespace v8 {
+namespace internal {
+
+// Abstract base class for handles that can operate on objects with differing
+// ElementsKinds.
+class ElementsAccessor {
+ public:
+  ElementsAccessor() { }
+  virtual ~ElementsAccessor() { }
+  virtual MaybeObject* GetWithReceiver(JSObject* obj,
+                                       Object* receiver,
+                                       uint32_t index) = 0;
+
+  // Returns a shared ElementsAccessor for the specified ElementsKind.
+  static ElementsAccessor* ForKind(JSObject::ElementsKind elements_kind) {
+    ASSERT(elements_kind < JSObject::kElementsKindCount);
+    return elements_accessors_[elements_kind];
+  }
+
+  static void InitializeOncePerProcess();
+
+ private:
+  static ElementsAccessor** elements_accessors_;
+
+  DISALLOW_COPY_AND_ASSIGN(ElementsAccessor);
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_ELEMENTS_H_