Implement .forEach() on typed arrays

test/mjsunit/harmony/typedarrays-foreach.js

+// 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.
+
+// Flags: --harmony-arrays --allow-natives-syntax
+
+var typedArrayConstructors = [
+  Uint8Array,
+  Int8Array,
+  Uint16Array,
+  Int16Array,
+  Uint32Array,
+  Int32Array,
+  Uint8ClampedArray,
+  Float32Array,
+  Float64Array];
+
+function TestTypedArrayForEach(constructor) {
+  assertEquals(1, constructor.prototype.forEach.length);
+
+  var a = new constructor(2);
+  a[0] = 0;
+  a[1] = 1;
+
+  var count = 0;
+  a.forEach(function (n) { count++; });
+  assertEquals(2, count);
+
+  // Use specified object as this object when calling the function.
+  var o = { value: 42 };
+  var result = [];
+  a.forEach(function (n, index, array) { result.push(this.value); }, o);
+  assertArrayEquals([42, 42], result);
+
+  // Modify the original array.
+  count = 0;
+  a.forEach(function (n, index, array) { array[index] = n + 1; count++ });
+  assertEquals(2, count);
+  assertArrayEquals([1, 2], a);
+
+  // Throw before completing iteration, only the first element
+  // should be modified when thorwing mid-way.
+  count = 0;
+  a[0] = 42;
+  a[1] = 42;
+  try {
+    a.forEach(function (n, index, array) {
+      if (count > 0) throw "meh";
+      array[index] = n + 1;
+      count++;
+    });
+  } catch (e) {
+  }
+  assertEquals(1, count);
+  assertEquals(43, a[0]);
+  assertEquals(42, a[1]);
+
+  // Neutering the buffer backing the typed array mid-way should
+  // still make .forEach() finish, and the array should keep being
+  // empty after neutering it.
+  count = 0;
+  a.forEach(function (n, index, array) {
+    if (count > 0) %ArrayBufferNeuter(array.buffer);
+    array[index] = n + 1;
+    count++;
+  });
+  assertEquals(0, a.length);
+  assertEquals(undefined, a[0]);

[Dmitry Lomov (no reviews), 2014/10/14 16:10:25]

Assert how many times you have executed the function.
Assert that the array you see after neutering is actually neutered

[aperez, 2014/10/15 15:54:48]

Acknowledged.

+
+  // The method must work for typed arrays created from ArrayBuffer.
+  // The length of the ArrayBuffer is chosen so it is a multiple of
+  // all lengths of the typed array items.
+  a = new constructor(new ArrayBuffer(64));
+  count = 0;
+  a.forEach(function (n) { count++ });
+  assertEquals(a.length, count);
+
+  // Externalizing the array mid-way accessing the .buffer property
+  // should work.
+  a = new constructor(2);
+  count = 0;
+  var buffer = undefined;
+  a.forEach(function (n, index, array) {
+    if (count++ > 0)
+      buffer = array.buffer;
+  });
+  assertEquals(2, count);
+  assertTrue(!!buffer);
+  assertEquals("ArrayBuffer", %_ClassOf(buffer));
+  assertSame(buffer, a.buffer);
+
+  // The %TypedArray%.forEach() method should not work when
+  // transplanted to objects that are not typed arrays.
+  assertThrows(function () { constructor.prototype.forEach.call([1, 2, 3], function (x) {}) }, TypeError);
+  assertThrows(function () { constructor.prototype.forEach.call("abc", function (x) {}) }, TypeError);
+  assertThrows(function () { constructor.prototype.forEach.call({}, function (x) {}) }, TypeError);
+  assertThrows(function () { constructor.prototype.forEach.call(0, function (x) {}) }, TypeError);
+
+  // Method must be useable on instances of other typed arrays.
+  for (var i = 0; i < typedArrayConstructors.length; i++) {
+    count = 0;
+    a = new typedArrayConstructors[i](4);
+    constructor.prototype.forEach.call(a, function (x) { count++ });
+    assertEquals(a.length, count);
+  }
+}
+
+for (i = 0; i < typedArrayConstructors.length; i++) {
+  TestTypedArrayForEach(typedArrayConstructors[i]);
+}