Resizable ArrayBuffer: DataView accessors (#3022)

* Add "feature" for "Resizable ArrayBuffer" proposal

* Resizable ArrayBuffer: DataView accessors

test/built-ins/DataView/prototype/byteLength/resizable-array-buffer-auto.js

@@ -0,0 +1,47 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-dataview.prototype.bytelength
+description: |
+  throws a TypeError if the underlying ArrayBuffer is resized beyond the
+  boundary of the dynamically-sized DataView instance
+features: [resizable-arraybuffer]
+---*/
+
+// If the host chooses to throw as allowed by the specification, the observed
+// behavior will be identical to the case where `ArrayBuffer.prototype.resize`
+// has not been implemented. The following assertion prevents this test from
+// passing in runtimes which have not implemented the method.
+assert.sameValue(typeof ArrayBuffer.prototype.resize, "function");
+
+var ab = new ArrayBuffer(4, {maxByteLength: 5});
+var dataView = new DataView(ab, 1);
+var expected = 3;
+
+assert.sameValue(dataView.byteLength, expected);
+
+try {
+  ab.resize(5);
+  expected = 4;
+} catch (_) {}
+
+assert.sameValue(dataView.byteLength, expected, "following grow");
+
+try {
+  ab.resize(3);
+  expected = 2;
+} catch (_) {}
+
+assert.sameValue(dataView.byteLength, expected, "following shrink (within bounds)");
+
+try {
+  ab.resize(1);
+  expected = TypeError;
+} catch (_) {
+  expected = Test262Error;
+}
+
+assert.throws(expected, function() {
+  dataView.byteLength;
+  throw new Test262Error('the operation completed successfully');
+});

test/built-ins/DataView/prototype/byteLength/resizable-array-buffer-fixed.js

@@ -0,0 +1,45 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-dataview.prototype.bytelength
+description: |
+  throws a TypeError if the underlying ArrayBuffer is resized beyond the
+  boundary of the fixed-sized DataView instance
+features: [resizable-arraybuffer]
+---*/
+
+// If the host chooses to throw as allowed by the specification, the observed
+// behavior will be identical to the case where `ArrayBuffer.prototype.resize`
+// has not been implemented. The following assertion prevents this test from
+// passing in runtimes which have not implemented the method.
+assert.sameValue(typeof ArrayBuffer.prototype.resize, "function");
+
+var ab = new ArrayBuffer(4, {maxByteLength: 5});
+var dataView = new DataView(ab, 1, 2);
+
+assert.sameValue(dataView.byteLength, 2);
+
+try {
+  ab.resize(5);
+} catch (_) {}
+
+assert.sameValue(dataView.byteLength, 2, "following grow");
+
+try {
+  ab.resize(3);
+} catch (_) {}
+
+assert.sameValue(dataView.byteLength, 2, "following shrink (within bounds)");
+
+var expectedError;
+try {
+  ab.resize(2);
+  expectedError = TypeError;
+} catch (_) {
+  expectedError = Test262Error;
+}
+
+assert.throws(expectedError, function() {
+  dataView.byteLength;
+  throw new Test262Error('the operation completed successfully');
+});

test/built-ins/DataView/prototype/byteOffset/resizable-array-buffer-auto.js

@@ -0,0 +1,45 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-dataview.prototype.byteoffset
+description: |
+  throws a TypeError if the underlying ArrayBuffer is resized beyond the
+  boundary of the dynamically-sized DataView instance
+features: [resizable-arraybuffer]
+---*/
+
+// If the host chooses to throw as allowed by the specification, the observed
+// behavior will be identical to the case where `ArrayBuffer.prototype.resize`
+// has not been implemented. The following assertion prevents this test from
+// passing in runtimes which have not implemented the method.
+assert.sameValue(typeof ArrayBuffer.prototype.resize, "function");
+
+var ab = new ArrayBuffer(4, {maxByteLength: 5});
+var dataView = new DataView(ab, 1);
+
+assert.sameValue(dataView.byteOffset, 1);
+
+try {
+  ab.resize(5);
+} catch (_) {}
+
+assert.sameValue(dataView.byteOffset, 1, "following grow");
+
+try {
+  ab.resize(3);
+} catch (_) {}
+
+assert.sameValue(dataView.byteOffset, 1, "following shrink (within bounds)");
+
+var expectedError;
+try {
+  ab.resize(1);
+  expectedError = TypeError;
+} catch (_) {
+  expectedError = Test262Error;
+}
+
+assert.throws(expectedError, function() {
+  dataView.byteOffset;
+  throw new Test262Error('the operation completed successfully');
+});

test/built-ins/DataView/prototype/byteOffset/resizable-array-buffer-fixed.js

@@ -0,0 +1,45 @@
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-get-dataview.prototype.byteoffset
+description: |
+  throws a TypeError if the underlying ArrayBuffer is resized beyond the
+  boundary of the fixed-sized DataView instance
+features: [resizable-arraybuffer]
+---*/
+
+// If the host chooses to throw as allowed by the specification, the observed
+// behavior will be identical to the case where `ArrayBuffer.prototype.resize`
+// has not been implemented. The following assertion prevents this test from
+// passing in runtimes which have not implemented the method.
+assert.sameValue(typeof ArrayBuffer.prototype.resize, "function");
+
+var ab = new ArrayBuffer(4, {maxByteLength: 5});
+var dataView = new DataView(ab, 1, 2);
+
+assert.sameValue(dataView.byteOffset, 1);
+
+try {
+  ab.resize(5);
+} catch (_) {}
+
+assert.sameValue(dataView.byteOffset, 1, "following grow");
+
+try {
+  ab.resize(BPE * 3);
+} catch (_) {}
+
+assert.sameValue(dataView.byteOffset, 1, "following shrink (within bounds)");
+
+var expectedError;
+try {
+  ab.resize(2);
+  expectedError = TypeError;
+} catch (_) {
+  expectedError = Test262Error;
+}
+
+assert.throws(expectedError, function() {
+  dataView.byteOffset;
+  throw new Test262Error('the operation completed successfully');
+});