1 files changed, 82 insertions, 0 deletions
diff --git a/browser/components/backup/actors/BackupUIParent.sys.mjs b/browser/components/backup/actors/BackupUIParent.sys.mjs
new file mode 100644
index 0000000000..e4d0f3aace
--- /dev/null
+++ b/browser/components/backup/actors/BackupUIParent.sys.mjs
@@ -0,0 +1,82 @@
+/* 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/. */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  BackupService: "resource:///modules/backup/BackupService.sys.mjs",
+});
+
+/**
+ * A JSWindowActor that is responsible for marshalling information between
+ * the BackupService singleton and any registered UI widgets that need to
+ * represent data from that service.
+ */
+export class BackupUIParent extends JSWindowActorParent {
+  /**
+   * A reference to the BackupService singleton instance.
+   *
+   * @type {BackupService}
+   */
+  #bs;
+
+  /**
+   * Create a BackupUIParent instance. If a BackupUIParent is instantiated
+   * before BrowserGlue has a chance to initialize the BackupService, this
+   * constructor will cause it to initialize first.
+   */
+  constructor() {
+    super();
+    // We use init() rather than get(), since it's possible to load
+    // about:preferences before the service has had a chance to init itself
+    // via BrowserGlue.
+    this.#bs = lazy.BackupService.init();
+  }
+
+  /**
+   * Called once the BackupUIParent/BackupUIChild pair have been connected.
+   */
+  actorCreated() {
+    this.#bs.addEventListener("BackupService:StateUpdate", this);
+  }
+
+  /**
+   * Called once the BackupUIParent/BackupUIChild pair have been disconnected.
+   */
+  didDestroy() {
+    this.#bs.removeEventListener("BackupService:StateUpdate", this);
+  }
+
+  /**
+   * Handles events fired by the BackupService.
+   *
+   * @param {Event} event
+   *   The event that the BackupService emitted.
+   */
+  handleEvent(event) {
+    if (event.type == "BackupService:StateUpdate") {
+      this.sendState();
+    }
+  }
+
+  /**
+   * Handles messages sent by BackupUIChild.
+   *
+   * @param {ReceiveMessageArgument} message
+   *   The message received from the BackupUIChild.
+   */
+  receiveMessage(message) {
+    if (message.name == "RequestState") {
+      this.sendState();
+    }
+  }
+
+  /**
+   * Sends the StateUpdate message to the BackupUIChild, along with the most
+   * recent state object from BackupService.
+   */
+  sendState() {
+    this.sendAsyncMessage("StateUpdate", { state: this.#bs.state });
+  }
+}