shared-string.js

// Copyright 2021 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-struct --shared-string-table --allow-natives-syntax

if (this.Worker) {

(function TestSharedStringPostMessage() {
  let workerScript =
      `let Box = new SharedStructType(['payload']);
       let b1 = new Box();
       b1.payload = "started";
       postMessage(b1);
       onmessage = function({data:box}) {
         if (!%IsSharedString(box.payload)) {
           throw new Error("str isn't shared");
         }
         let b2 = new Box();
         b2.payload = box.payload;
         postMessage(b2);
       };`;

  // Strings referenced in shared structs are serialized by sharing.

  let worker = new Worker(workerScript, { type: 'string' });
  let started = worker.getMessage();
  assertTrue(%IsSharedString(started.payload));
  assertEquals("started", started.payload);

  // The string literal appears in source and is internalized, so should
  // already be shared.
  let Box = new SharedStructType(['payload']);
  let box_to_send = new Box();
  box_to_send.payload = 'foo';
  assertTrue(%IsSharedString(box_to_send.payload));
  worker.postMessage(box_to_send);
  let box_received = worker.getMessage();
  assertTrue(%IsSharedString(box_received.payload));
  assertFalse(box_to_send === box_received);
  // Object.is and === won't check pointer equality of Strings.
  assertTrue(%IsSameHeapObject(box_to_send.payload, box_received.payload));

  worker.terminate();
})();

}