function clearMetrics()

in glean/src/core/glean.ts [131:182]
21 lines of code
2 McCabe index (conditional complexity)

  function clearMetrics(): void {
    // Clear enqueued upload jobs and clear pending pings queue.
    //
    // The only job that will still be sent is the deletion-request ping.
    pingUploader.clearPendingPingsQueue();

    // There is only one metric that we want to survive after clearing all
    // metrics: first_run_date. Here, we store its value
    // so we can restore it after clearing the metrics.
    //
    // Note: This will throw in case the stored metric is incorrect or inexistent.
    // The most likely is that it throws if the metrics hasn't been set,
    // e.g. we start Glean for the first with upload disabled.
    let firstRunDate: Date;
    try {
      firstRunDate = new DatetimeMetric(
        Context.metricsDatabase.getMetric(
          CLIENT_INFO_STORAGE,
          Context.coreMetrics.firstRunDate
        )
      ).date;
    } catch {
      firstRunDate = new Date();
    }

    // Clear the databases.
    Context.eventsDatabase.clearAll();
    Context.metricsDatabase.clearAll();
    Context.pingsDatabase.clearAll();

    // We need to briefly set upload_enabled to true here so that `set`
    // is not a no-op.
    //
    // This is safe.
    //
    // `clearMetrics` is either called on `initialize` or `setUploadEnabled`.
    // Both are dispatched tasks, which means that any other dispatched task
    // called after them will only be executed after they are done.
    // Since all external API calls are dispatched, it is not possible
    // for any other API call to be execute concurrently with this one.
    Context.uploadEnabled = true;

    // Store a "dummy" KNOWN_CLIENT_ID in the client_id metric. This will
    // make it easier to detect if pings were unintentionally sent after
    // uploading is disabled.
    Context.coreMetrics.clientId.set(KNOWN_CLIENT_ID);

    // Restore the first_run_date.
    Context.coreMetrics.firstRunDate.set(firstRunDate);

    Context.uploadEnabled = false;
  }