ES6 symbols: extend V8 API to support symbols

include/v8.h

Index: include/v8.h
diff --git a/include/v8.h b/include/v8.h
index 9adb1c041cf20bd2ed12d7a04dfe07c53cd1712b..d0c4f5409c3503b1c02f58e97fb8fc38f8c2d3df 100644
--- a/include/v8.h
+++ b/include/v8.h
@@ -127,6 +127,8 @@ class StackFrame;
 class StackTrace;
 class String;
 class StringObject;
+class Symbol;
+class SymbolObject;
 class Uint32;
 class Utils;
 class Value;
@@ -973,6 +975,12 @@ class V8EXPORT Value : public Data {
   V8_INLINE(bool IsString() const);
 
   /**
+   * Returns true if this value is a symbol.
+   * This is an experimental feature.
+   */
+  bool IsSymbol() const;
+
+  /**
    * Returns true if this value is a function.
    */
   bool IsFunction() const;
@@ -1033,6 +1041,12 @@ class V8EXPORT Value : public Data {
   bool IsStringObject() const;
 
   /**
+   * Returns true if this value is a Symbol object.
+   * This is an experimental feature.
+   */
+  bool IsSymbolObject() const;
+
+  /**
    * Returns true if this value is a NativeError.
    */
   bool IsNativeError() const;
@@ -1311,7 +1325,11 @@ class V8EXPORT String : public Primitive {
   /** Allocates a new string from 16-bit character codes.*/
   static Local<String> New(const uint16_t* data, int length = -1);
 
-  /** Creates a symbol. Returns one if it exists already.*/
+  /**
+   * Creates an internalized string (historically called a "symbol",
+   * not to be confused with ES6 symbols). Returns one if it exists already.
+   * TODO(rossberg): Deprecate me when the new string API is here.
+   */
   static Local<String> NewSymbol(const char* data, int length = -1);
 
   /**
@@ -1450,6 +1468,29 @@ class V8EXPORT String : public Primitive {
 
 
 /**
+ * A JavaScript symbol (ECMA-262 edition 6)
+ *
+ * This is an experimental feature. Use at your own risk.
+ */
+class V8EXPORT Symbol : public Primitive {
+ public:
+  // Returns the print name string of the symbol, or undefined if none.
+  Local<Value> Name() const;
+
+  // Create a symbol without a print name.
+  static Local<Symbol> New(Isolate* isolate);
+
+  // Create a symbol with a print name.
+  static Local<Symbol> New(Isolate *isolate, const char* data, int length = -1);
+
+  V8_INLINE(static Symbol* Cast(v8::Value* obj));
+ private:
+  Symbol();
+  static void CheckCast(v8::Value* obj);
+};
+
+
+/**
  * A JavaScript number value (ECMA-262, 4.3.20)
  */
 class V8EXPORT Number : public Primitive {
@@ -1590,11 +1631,9 @@ class V8EXPORT Object : public Value {
    */
   PropertyAttribute GetPropertyAttributes(Handle<Value> key);
 
-  // TODO(1245389): Replace the type-specific versions of these
-  // functions with generic ones that accept a Handle<Value> key.
-  bool Has(Handle<String> key);
+  bool Has(Handle<Value> key);
 
-  bool Delete(Handle<String> key);
+  bool Delete(Handle<Value> key);
 
   // Delete a property on this object bypassing interceptors and
   // ignoring dont-delete attributes.
@@ -1982,6 +2021,27 @@ class V8EXPORT StringObject : public Object {
 
 
 /**
+ * A Symbol object (ECMA-262 edition 6).
+ *
+ * This is an experimental feature. Use at your own risk.
+ */
+class V8EXPORT SymbolObject : public Object {
+ public:
+  static Local<Value> New(Isolate* isolate, Handle<Symbol> value);
+
+  /**
+   * Returns the Symbol held by the object.
+   */
+  Local<Symbol> SymbolValue() const;
+
+  V8_INLINE(static SymbolObject* Cast(v8::Value* obj));
+
+ private:
+  static void CheckCast(v8::Value* obj);
+};
+
+
+/**
  * An instance of the built-in RegExp constructor (ECMA-262, 15.10).
  */
 class V8EXPORT RegExp : public Object {
@@ -4847,6 +4907,14 @@ bool Value::QuickIsString() const {
 }
 
 
+Symbol* Symbol::Cast(v8::Value* value) {
+#ifdef V8_ENABLE_CHECKS
+  CheckCast(value);
+#endif
+  return static_cast<Symbol*>(value);
+}
+
+
 Number* Number::Cast(v8::Value* value) {
 #ifdef V8_ENABLE_CHECKS
   CheckCast(value);
@@ -4879,6 +4947,14 @@ StringObject* StringObject::Cast(v8::Value* value) {
 }
 
 
+SymbolObject* SymbolObject::Cast(v8::Value* value) {
+#ifdef V8_ENABLE_CHECKS
+  CheckCast(value);
+#endif
+  return static_cast<SymbolObject*>(value);
+}
+
+
 NumberObject* NumberObject::Cast(v8::Value* value) {
 #ifdef V8_ENABLE_CHECKS
   CheckCast(value);