1 files changed, 119 insertions, 0 deletions
diff --git a/toolkit/components/terminator/TerminatorTelemetry.sys.mjs b/toolkit/components/terminator/TerminatorTelemetry.sys.mjs
new file mode 100644
index 0000000000..9903027436
--- /dev/null
+++ b/toolkit/components/terminator/TerminatorTelemetry.sys.mjs
@@ -0,0 +1,119 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80 filetype=javascript: */
+/* 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/. */
+
+/**
+ * Read the data saved by nsTerminator during shutdown and feed it to the
+ * relevant telemetry histograms.
+ */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  setTimeout: "resource://gre/modules/Timer.sys.mjs",
+});
+
+export function nsTerminatorTelemetry() {
+  this._wasNotified = false;
+  this._deferred = Promise.withResolvers();
+
+  IOUtils.sendTelemetry.addBlocker(
+    "TerminatoryTelemetry: Waiting to submit telemetry",
+    this._deferred.promise,
+    () => ({
+      wasNotified: this._wasNotified,
+    })
+  );
+}
+
+var HISTOGRAMS = {
+  "quit-application": "SHUTDOWN_PHASE_DURATION_TICKS_QUIT_APPLICATION",
+  "profile-change-net-teardown":
+    "SHUTDOWN_PHASE_DURATION_TICKS_PROFILE_CHANGE_NET_TEARDOWN",
+  "profile-change-teardown":
+    "SHUTDOWN_PHASE_DURATION_TICKS_PROFILE_CHANGE_TEARDOWN",
+  "profile-before-change":
+    "SHUTDOWN_PHASE_DURATION_TICKS_PROFILE_BEFORE_CHANGE",
+  "profile-before-change-qm":
+    "SHUTDOWN_PHASE_DURATION_TICKS_PROFILE_BEFORE_CHANGE_QM",
+  "xpcom-will-shutdown": "SHUTDOWN_PHASE_DURATION_TICKS_XPCOM_WILL_SHUTDOWN",
+  "xpcom-shutdown": "SHUTDOWN_PHASE_DURATION_TICKS_XPCOM_SHUTDOWN",
+
+  // The following keys appear in the JSON, but do not have associated
+  // histograms.
+  "xpcom-shutdown-threads": null,
+  XPCOMShutdownFinal: null,
+  CCPostLastCycleCollection: null,
+};
+
+nsTerminatorTelemetry.prototype = {
+  classID: Components.ID("{3f78ada1-cba2-442a-82dd-d5fb300ddea7}"),
+
+  // nsISupports
+
+  QueryInterface: ChromeUtils.generateQI(["nsIObserver"]),
+
+  // nsIObserver
+
+  observe: function DS_observe(aSubject, aTopic, aData) {
+    this._wasNotified = true;
+
+    (async () => {
+      try {
+        //
+        // This data is hardly critical, reading it can wait for a few seconds.
+        //
+        await new Promise(resolve => lazy.setTimeout(resolve, 3000));
+
+        let PATH = PathUtils.join(
+          Services.dirsvc.get("ProfLD", Ci.nsIFile).path,
+          "ShutdownDuration.json"
+        );
+        let data;
+        try {
+          data = await IOUtils.readJSON(PATH);
+        } catch (ex) {
+          if (DOMException.isInstance(ex) && ex.name == "NotFoundError") {
+            return;
+          }
+          // Let other errors be reported by Promise's error-reporting.
+          throw ex;
+        }
+
+        // Clean up
+        await IOUtils.remove(PATH);
+        await IOUtils.remove(PATH + ".tmp");
+
+        for (let k of Object.keys(data)) {
+          let id = HISTOGRAMS[k];
+          if (id === null) {
+            // No histogram associated with this entry.
+            continue;
+          }
+
+          try {
+            let histogram = Services.telemetry.getHistogramById(id);
+            histogram.add(Number.parseInt(data[k]));
+          } catch (ex) {
+            // Make sure that the error is reported and causes test failures,
+            // but otherwise, ignore it.
+            Promise.reject(ex);
+            continue;
+          }
+        }
+
+        // Inform observers that we are done.
+        Services.obs.notifyObservers(
+          null,
+          "shutdown-terminator-telemetry-updated"
+        );
+      } finally {
+        this._deferred.resolve();
+      }
+    })();
+  },
+};
+
+// Module