Implement .forEach() on typed arrays

src/harmony-typedarray.js

Index: src/harmony-typedarray.js
diff --git a/src/harmony-typedarray.js b/src/harmony-typedarray.js
new file mode 100644
index 0000000000000000000000000000000000000000..0b334b57b1540269130e431636a35289da8236be
--- /dev/null
+++ b/src/harmony-typedarray.js
@@ -0,0 +1,78 @@
+// Copyright 2014 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.
+
+'use strict';
+
+// This file relies on the fact that the following declaration has been made
+// in runtime.js:
+// var $Array = global.Array;
+
+// -------------------------------------------------------------------
+
+macro TYPED_ARRAYS(FUNCTION)
+// arrayIds below should be synchronized with Runtime_TypedArrayInitialize.
+FUNCTION(1, Uint8Array, 1)
+FUNCTION(2, Int8Array, 1)
+FUNCTION(3, Uint16Array, 2)
+FUNCTION(4, Int16Array, 2)
+FUNCTION(5, Uint32Array, 4)
+FUNCTION(6, Int32Array, 4)
+FUNCTION(7, Float32Array, 4)
+FUNCTION(8, Float64Array, 8)
+FUNCTION(9, Uint8ClampedArray, 1)
+endmacro
+
+
+macro TYPED_ARRAY_CONSTRUCTOR(ARRAY_ID, NAME, ELEMENT_SIZE)
+
+// ES6 draft 08-24-14, section 22.2.3.12
+function NAMEForEach(f /* thisArg */) {  // length == 1
+  if (!(%_ClassOf(this) === 'NAME')) {

[wingo, 2014/09/23 18:11:25]

Not sure this is right; although the function isn't generic, as specified it
would seem to work on any kind of typedarray.

+    throw MakeTypeError('incompatible_method_receiver',
+        ['NAME.forEach', this]);
+  }

[wingo, 2014/09/23 18:11:25]

Also what about the text that says "A TypeError exception is also immediately
thrown if the this value is detached or if its [[ViewedArrayBuffer]] is." ?

+  if (!IS_SPEC_FUNCTION(f)) {
+    throw MakeTypeError('called_non_callable', [ f ]);
+  }
+
+  var length = %_TypedArrayGetLength(this);
+  var receiver;
+
+  if (%_ArgumentsLength() > 1) {
+    receiver = %_Arguments(1);
+  }
+
+  if (IS_NULL_OR_UNDEFINED(receiver)) {
+    receiver = %GetDefaultReceiver(f) || receiver;
+  }
+  var needs_wrapper = SHOULD_CREATE_WRAPPER(f, receiver);
+
+  var stepping = DEBUG_IS_ACTIVE && %DebugCallbackSupportsStepping(f);
+  for (var i = 0; i < length; i++) {
+    var element = this[i];
+    // Prepare break slots for debugger step in.
+    if (stepping) %DebugPrepareStepInIfStepping(f);
+    var new_receiver = needs_wrapper ? ToObject(receiver) : receiver;
+    %_CallFunction(new_receiver, TO_OBJECT_INLINE(element), i, this, f);
+  }
+}
+endmacro
+
+TYPED_ARRAYS(TYPED_ARRAY_CONSTRUCTOR)
+
+
+function HarmonyTypedArrayExtendPrototypes() {
+macro EXTEND_TYPED_ARRAY(ARRAY_ID, NAME, ELEMENT_SIZE)
+  %CheckIsBootstrapping();
+
+  // Set up non-enumerable functions on the prototype object.
+  InstallFunctions(global.NAME.prototype, DONT_ENUM, $Array(
+    "forEach", NAMEForEach
+  ));
+endmacro
+
+  TYPED_ARRAYS(EXTEND_TYPED_ARRAY)
+}
+
+HarmonyTypedArrayExtendPrototypes();