Bug 645416, part 16 - Implement Symbol.prototype.valueOf. r=sfink.

--HG--
extra : rebase_source : 12dfad71e0933ccc3e553854f44bdf0f85eccf64

js/src/builtin/SymbolObject.cpp

@@ -44,6 +44,7 @@ const JSPropertySpec SymbolObject::properties[] = {
 
 const JSFunctionSpec SymbolObject::methods[] = {
     JS_FN(js_toString_str, toString, 0, 0),
+    JS_FN(js_valueOf_str, valueOf, 0, 0),
     JS_FS_END
 };
 
@@ -183,6 +184,27 @@ SymbolObject::toString(JSContext *cx, unsigned argc, Value *vp)
     return CallNonGenericMethod<IsSymbol, toString_impl>(cx, args);
 }
 
+//ES6 rev 24 (2014 Apr 27) 19.4.3.3
+bool
+SymbolObject::valueOf_impl(JSContext *cx, CallArgs args)
+{
+    // Step 3, the error case, is handled by CallNonGenericMethod.
+    HandleValue thisv = args.thisv();
+    MOZ_ASSERT(IsSymbol(thisv));
+    if (thisv.isSymbol())
+        args.rval().set(thisv);
+    else
+        args.rval().setSymbol(thisv.toObject().as<SymbolObject>().unbox());
+    return true;
+}
+
+bool
+SymbolObject::valueOf(JSContext *cx, unsigned argc, Value *vp)
+{
+    CallArgs args = CallArgsFromVp(argc, vp);
+    return CallNonGenericMethod<IsSymbol, valueOf_impl>(cx, args);
+}
+
 JSObject *
 js_InitSymbolClass(JSContext *cx, HandleObject obj)
 {

js/src/builtin/SymbolObject.h

@@ -48,6 +48,8 @@ class SymbolObject : public JSObject
     // Methods defined on Symbol.prototype.
     static bool toString_impl(JSContext *cx, CallArgs args);
     static bool toString(JSContext *cx, unsigned argc, Value *vp);
+    static bool valueOf_impl(JSContext *cx, CallArgs args);
+    static bool valueOf(JSContext *cx, unsigned argc, Value *vp);
 
     static const JSPropertySpec properties[];
     static const JSFunctionSpec methods[];

js/src/tests/ecma_6/Symbol/as-base-value.js

@@ -22,6 +22,7 @@ Object.defineProperty(Symbol.prototype, "prop", {
         gets++;
         assertEq(typeof this, "object");
         assertEq(this instanceof Symbol, true);
+        assertEq(this.valueOf(), sym);
         return "got";
     },
     set: function (v) {
@@ -29,6 +30,7 @@ Object.defineProperty(Symbol.prototype, "prop", {
         sets++;
         assertEq(typeof this, "object");
         assertEq(this instanceof Symbol, true);
+        assertEq(this.valueOf(), sym);
         assertEq(v, "newvalue");
     }
 });
@@ -44,6 +46,7 @@ for (var sym of symbols) {
     Symbol.prototype.nonStrictMethod = function (arg) {
         assertEq(arg, "ok");
         assertEq(this instanceof Symbol, true);
+        assertEq(this.valueOf(), sym);
         return 13;
     };
     assertEq(sym.nonStrictMethod("ok"), 13);

js/src/tests/ecma_6/Symbol/constructor.js

@@ -26,5 +26,8 @@ assertEq(hits, 1);
 
 assertEq(Object.getPrototypeOf(Symbol.prototype), Object.prototype);
 
+// Symbol.prototype is not itself a Symbol object.
+assertThrowsInstanceOf(() => Symbol.prototype.valueOf(), TypeError);
+
 if (typeof reportCompare === "function")
     reportCompare(0, 0);

js/src/tests/ecma_6/Symbol/surfaces.js

@@ -23,6 +23,7 @@ assertEq(desc.writable, true);
 
 assertEq(Symbol.for.length, 1);
 assertEq(Symbol.prototype.toString.length, 0);
+assertEq(Symbol.prototype.valueOf.length, 0);
 
 if (typeof reportCompare === "function")
     reportCompare(0, 0);

js/src/tests/ecma_6/Symbol/valueOf.js

@@ -0,0 +1,22 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/ */
+
+var symbols = [
+    Symbol(),
+    Symbol("ok"),
+    Symbol.for("dummies"),
+    Symbol.iterator
+];
+
+for (var sym of symbols) {
+    assertEq(sym.valueOf(), sym);
+    assertEq(Object(sym).valueOf(), sym);
+}
+
+// Any other value throws.
+var nonsymbols = [undefined, null, NaN, {}, Symbol.prototype];
+for (var nonsym of nonsymbols)
+    assertThrowsInstanceOf(() => Symbol.prototype.valueOf.call(nonsym), TypeError);
+
+if (typeof reportCompare === "function")
+    reportCompare(0, 0);