1 files changed, 80 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/infrastructure/safe-passing-of-structured-data/shared-array-buffers/resources/test-incrementer.js b/testing/web-platform/tests/html/infrastructure/safe-passing-of-structured-data/shared-array-buffers/resources/test-incrementer.js
new file mode 100644
index 0000000000..9c3fb813ae
--- /dev/null
+++ b/testing/web-platform/tests/html/infrastructure/safe-passing-of-structured-data/shared-array-buffers/resources/test-incrementer.js
@@ -0,0 +1,80 @@
+"use strict";
+
+self.getViewValue = (view, index) => {
+  if(view instanceof DataView) {
+    return view.getInt8(index);
+  }
+  return view[index];
+};
+
+self.setViewValue = (view, index, value) => {
+  if(view instanceof DataView) {
+    view.setInt8(index, value);
+  } else {
+    view[index] = value;
+  }
+};
+
+self.maybeBigInt = (view, value) => {
+  if (view.constructor.name === "BigInt64Array" || view.constructor.name === "BigUint64Array") {
+    return BigInt(value);
+  }
+  return value;
+};
+
+self.testSharingViaIncrementerScript = (t, whereToListen, whereToListenLabel, whereToSend, whereToSendLabel, origin, type = "Int32Array") => {
+  return new Promise(resolve => {
+    const sab = new SharedArrayBuffer(8);
+    const view = new self[type](sab);
+    setViewValue(view, 0, maybeBigInt(view, 1));
+
+    whereToListen.onmessage = t.step_func(({ data }) => {
+      switch (data.message) {
+        case "initial payload received": {
+          assert_equals(data.value, maybeBigInt(view, 1), `The ${whereToSendLabel} must see the same value in the SharedArrayBuffer`);
+          break;
+        }
+
+        case "changed to 2": {
+          assert_equals(getViewValue(view, 0), maybeBigInt(view, 2), `The ${whereToListenLabel} must see changes made in the ${whereToSendLabel}`);
+
+          setViewValue(view, 0, maybeBigInt(view, 3));
+          whereToSend.postMessage({ message: "changed to 3" }, origin);
+
+          break;
+        }
+
+        case "changed to 3 received": {
+          assert_equals(data.value, maybeBigInt(view, 3), `The ${whereToSendLabel} must see changes made in the ${whereToListenLabel}`);
+          resolve();
+          break;
+        }
+      }
+    });
+
+    whereToSend.postMessage({ message: "initial payload", view }, origin);
+  });
+};
+
+self.setupDestinationIncrementer = (whereToListen, whereToSendBackTo, origin) => {
+  let view;
+  whereToListen.onmessage = ({ data }) => {
+    switch (data.message) {
+      case "initial payload": {
+        view = data.view;
+        whereToSendBackTo.postMessage({ message: "initial payload received", value: getViewValue(view, 0) }, origin);
+
+        setViewValue(view, 0, maybeBigInt(view, 2));
+        whereToSendBackTo.postMessage({ message: "changed to 2" }, origin);
+
+        break;
+      }
+
+      case "changed to 3": {
+        whereToSendBackTo.postMessage({ message: "changed to 3 received", value: getViewValue(view, 0) }, origin);
+
+        break;
+      }
+    }
+  };
+};