Add Object::IsNullOrUndefined(Isolate*) helper method

include/v8.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.
 
 /** \mainpage V8 API Reference Guide
  *
  * V8 is Google's open source JavaScript engine.
  *
  * This set of documents provides reference material generated from the
  * V8 header file, include/v8.h.
@@ skipping 1903 matching lines @@
    * 4.3.10.
    */
   V8_INLINE bool IsUndefined() const;
 
   /**
    * Returns true if this value is the null value.  See ECMA-262
    * 4.3.11.
    */
   V8_INLINE bool IsNull() const;
 
-   /**
-   * Returns true if this value is true.
+  /**
+   * Returns true if this value is either the null or the undefined value.
+   * See ECMA-262
+   * 4.3.11. and 4.3.12
    */
+  V8_INLINE bool IsNullOrUndefined() const;
+
+  /**
+  * Returns true if this value is true.
+  */
   bool IsTrue() const;
 
   /**
    * Returns true if this value is false.
    */
   bool IsFalse() const;
 
   /**
    * Returns true if this value is a symbol or a string.
    */
@@ skipping 299 matching lines @@
   bool StrictEquals(Local<Value> that) const;
   bool SameValue(Local<Value> that) const;
 
   template <class T> V8_INLINE static Value* Cast(T* value);
 
   Local<String> TypeOf(Isolate*);
 
  private:
   V8_INLINE bool QuickIsUndefined() const;
   V8_INLINE bool QuickIsNull() const;
+  V8_INLINE bool QuickIsNullOrUndefined() const;
   V8_INLINE bool QuickIsString() const;
   bool FullIsUndefined() const;
   bool FullIsNull() const;
   bool FullIsString() const;
 };
 
 
 /**
  * The superclass of primitive values.  See ECMA-262 4.3.2.
  */
@@ skipping 6881 matching lines @@
 
 bool Value::QuickIsNull() const {
   typedef internal::Object O;
   typedef internal::Internals I;
   O* obj = *reinterpret_cast<O* const*>(this);
   if (!I::HasHeapObjectTag(obj)) return false;
   if (I::GetInstanceType(obj) != I::kOddballType) return false;
   return (I::GetOddballKind(obj) == I::kNullOddballKind);
 }
 
+bool Value::IsNullOrUndefined() const {
+#ifdef V8_ENABLE_CHECKS
+  return FullIsNull() || FullIsUndefined();
+#else
+  return QuickIsNullOrUndefined();
+#endif
+}
+
+bool Value::QuickIsNullOrUndefined() const {
+  typedef internal::Object O;
+  typedef internal::Internals I;
+  O* obj = *reinterpret_cast<O* const*>(this);
+  if (!I::HasHeapObjectTag(obj)) return false;
+  if (I::GetInstanceType(obj) != I::kOddballType) return false;
+  int kind = I::GetOddballKind(obj);
+  return kind == I::kNullOddballKind || kind == I::kUndefinedOddballKind;
+}
 
 bool Value::IsString() const {
 #ifdef V8_ENABLE_CHECKS
   return FullIsString();
 #else
   return QuickIsString();
 #endif
 }
 
 bool Value::QuickIsString() const {
@@ skipping 618 matching lines @@
  */
 
 
 }  // namespace v8
 
 
 #undef TYPE_CHECK
 
 
 #endif  // INCLUDE_V8_H_