1 files changed, 68 insertions, 0 deletions
diff --git a/devtools/server/actors/resources/extensions-backgroundscript-status.js b/devtools/server/actors/resources/extensions-backgroundscript-status.js
new file mode 100644
index 0000000000..08f51a23f5
--- /dev/null
+++ b/devtools/server/actors/resources/extensions-backgroundscript-status.js
@@ -0,0 +1,68 @@
+/* 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/. */
+
+"use strict";
+
+const {
+  TYPES: { EXTENSIONS_BGSCRIPT_STATUS },
+} = require("resource://devtools/server/actors/resources/index.js");
+
+class ExtensionsBackgroundScriptStatusWatcher {
+  /**
+   * Start watching for the status updates related to a background
+   * scripts extension context (either an event page or a background
+   * service worker).
+   *
+   * This is used in about:debugging to update the background script
+   * row updated visible in Extensions details cards (only for extensions
+   * with a non persistent background script defined in the manifest)
+   * when the background contex is terminated on idle or started back
+   * to handle a persistent WebExtensions API event.
+   *
+   * @param RootActor rootActor
+   *        The root actor in the parent process from which we should
+   *        observe root resources.
+   * @param Object options
+   *        Dictionary object with following attributes:
+   *        - onAvailable: mandatory function
+   *          This will be called for each resource.
+   */
+  async watch(rootActor, { onAvailable }) {
+    this.rootActor = rootActor;
+    this.onAvailable = onAvailable;
+
+    Services.obs.addObserver(this, "extension:background-script-status");
+  }
+
+  observe(subject, topic, data) {
+    switch (topic) {
+      case "extension:background-script-status": {
+        const { addonId, isRunning } = subject.wrappedJSObject;
+        this.onBackgroundScriptStatus(addonId, isRunning);
+        break;
+      }
+    }
+  }
+
+  onBackgroundScriptStatus(addonId, isRunning) {
+    this.onAvailable([
+      {
+        resourceType: EXTENSIONS_BGSCRIPT_STATUS,
+        payload: {
+          addonId,
+          isRunning,
+        },
+      },
+    ]);
+  }
+
+  destroy() {
+    if (this.onAvailable) {
+      this.onAvailable = null;
+      Services.obs.removeObserver(this, "extension:background-script-status");
+    }
+  }
+}
+
+module.exports = ExtensionsBackgroundScriptStatusWatcher;