Adding ElementsAccessor::Slice

src/elements.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ELEMENTS_H_
 #define V8_ELEMENTS_H_
 
 #include "src/elements-kind.h"
 #include "src/heap/heap.h"
 #include "src/isolate.h"
@@ skipping 20 matching lines @@
   // in the backing store to use for the check, which must be compatible with
   // the ElementsKind of the ElementsAccessor. If backing_store is NULL, the
   // holder->elements() is used as the backing store.
   virtual bool HasElement(Handle<JSObject> holder, uint32_t index,
                           Handle<FixedArrayBase> backing_store) = 0;
 
   inline bool HasElement(Handle<JSObject> holder, uint32_t index) {
     return HasElement(holder, index, handle(holder->elements()));
   }
 
+  // Returns true if the backing store is compact in the given range
+  virtual bool IsPacked(Handle<JSObject> holder,
+                        Handle<FixedArrayBase> backing_store, uint32_t start,
+                        uint32_t end) = 0;
+
   virtual Handle<Object> Get(Handle<FixedArrayBase> backing_store,
                              uint32_t entry) = 0;
 
   // Modifies the length data property as specified for JSArrays and resizes the
   // underlying backing store accordingly. The method honors the semantics of
   // changing array sizes as defined in EcmaScript 5.1 15.4.5.2, i.e. array that
   // have non-deletable elements can only be shrunk to the size of highest
   // element that is non-deletable.
   virtual void SetLength(Handle<JSArray> holder, uint32_t new_length) = 0;
 
@@ skipping 73 matching lines @@
   virtual void Add(Handle<JSObject> object, uint32_t index,
                    Handle<Object> value, PropertyAttributes attributes,
                    uint32_t new_capacity) = 0;
 
   // TODO(cbruni): Consider passing Arguments* instead of Object** depending on
   // the requirements of future callers.
   virtual uint32_t Push(Handle<JSArray> receiver,
                         Handle<FixedArrayBase> backing_store, Object** objects,
                         uint32_t start, int direction) = 0;
 
+  virtual Handle<JSArray> Slice(Handle<JSObject> receiver,
+                                Handle<FixedArrayBase> backing_store,
+                                uint32_t start, uint32_t end) = 0;
+
   virtual Handle<JSArray> Splice(Handle<JSArray> receiver,
                                  Handle<FixedArrayBase> backing_store,
                                  uint32_t start, uint32_t delete_count,
                                  Arguments args, uint32_t add_count) = 0;
 
  protected:
   friend class LookupIterator;
 
   static ElementsAccessor* ForArray(FixedArrayBase* array);
 
@@ skipping 24 matching lines @@
 void CheckArrayAbuse(Handle<JSObject> obj, const char* op, uint32_t index,
                      bool allow_appending = false);
 
 MUST_USE_RESULT MaybeHandle<Object> ArrayConstructInitializeElements(
     Handle<JSArray> array,
     Arguments* args);
 
 } }  // namespace v8::internal
 
 #endif  // V8_ELEMENTS_H_