1 files changed, 59 insertions, 0 deletions
diff --git a/toolkit/components/contentprefs/tests/unit_cps2/AsyncRunner.sys.mjs b/toolkit/components/contentprefs/tests/unit_cps2/AsyncRunner.sys.mjs
new file mode 100644
index 0000000000..3fab7c981f
--- /dev/null
+++ b/toolkit/components/contentprefs/tests/unit_cps2/AsyncRunner.sys.mjs
@@ -0,0 +1,59 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+export function AsyncRunner(callbacks) {
+  this._callbacks = callbacks;
+  this._iteratorQueue = [];
+
+  // This catches errors reported to the console, e.g., via Cu.reportError.
+  Services.console.registerListener(this);
+}
+
+AsyncRunner.prototype = {
+  appendIterator: function AR_appendIterator(iter) {
+    this._iteratorQueue.push(iter);
+  },
+
+  next: function AR_next(arg) {
+    if (!this._iteratorQueue.length) {
+      this.destroy();
+      this._callbacks.done();
+      return;
+    }
+
+    try {
+      var { done, value } = this._iteratorQueue[0].next(arg);
+      if (done) {
+        this._iteratorQueue.shift();
+        this.next();
+        return;
+      }
+    } catch (err) {
+      this._callbacks.error(err);
+    }
+
+    // val is truthy => call next
+    // val is an iterator => prepend it to the queue and start on it
+    if (value) {
+      if (typeof value != "boolean") {
+        this._iteratorQueue.unshift(value);
+      }
+      this.next();
+    }
+  },
+
+  destroy: function AR_destroy() {
+    Services.console.unregisterListener(this);
+    this.destroy = function AR_alreadyDestroyed() {};
+  },
+
+  observe: function AR_consoleServiceListener(msg) {
+    if (
+      msg instanceof Ci.nsIScriptError &&
+      !(msg.flags & Ci.nsIScriptError.warningFlag)
+    ) {
+      this._callbacks.consoleError(msg);
+    }
+  },
+};