Bug 1440421 part 2. Mirror https://github.com/mozilla/activity-stream repository layout in browser/extensions/activity-stream. r=k88hudson

MozReview-Commit-ID: HyAUvAgOVEV
2018-06-06 10:44:53 -07:00
parent 8eb412b37e
commit 98c73af634
219 changed files with 44883 additions and 16 deletions
--- a/browser/extensions/activity-stream/content-src/lib/detect-user-session-start.js
+++ b/browser/extensions/activity-stream/content-src/lib/detect-user-session-start.js
@@ -0,0 +1,65 @@
+import {actionCreators as ac, actionTypes as at} from "common/Actions.jsm";
+import {perfService as perfSvc} from "common/PerfService.jsm";
+
+const VISIBLE = "visible";
+const VISIBILITY_CHANGE_EVENT = "visibilitychange";
+
+export class DetectUserSessionStart {
+  constructor(store, options = {}) {
+    this._store = store;
+    // Overrides for testing
+    this.document = options.document || global.document;
+    this._perfService = options.perfService || perfSvc;
+    this._onVisibilityChange = this._onVisibilityChange.bind(this);
+  }
+
+  /**
+   * sendEventOrAddListener - Notify immediately if the page is already visible,
+   *                    or else set up a listener for when visibility changes.
+   *                    This is needed for accurate session tracking for telemetry,
+   *                    because tabs are pre-loaded.
+   */
+  sendEventOrAddListener() {
+    if (this.document.visibilityState === VISIBLE) {
+      // If the document is already visible, to the user, send a notification
+      // immediately that a session has started.
+      this._sendEvent();
+    } else {
+      // If the document is not visible, listen for when it does become visible.
+      this.document.addEventListener(VISIBILITY_CHANGE_EVENT, this._onVisibilityChange);
+    }
+  }
+
+  /**
+   * _sendEvent - Sends a message to the main process to indicate the current
+   *              tab is now visible to the user, includes the
+   *              visibility_event_rcvd_ts time in ms from the UNIX epoch.
+   */
+  _sendEvent() {
+    this._perfService.mark("visibility_event_rcvd_ts");
+
+    try {
+      let visibility_event_rcvd_ts = this._perfService
+        .getMostRecentAbsMarkStartByName("visibility_event_rcvd_ts");
+
+      this._store.dispatch(ac.AlsoToMain({
+        type: at.SAVE_SESSION_PERF_DATA,
+        data: {visibility_event_rcvd_ts}
+      }));
+    } catch (ex) {
+      // If this failed, it's likely because the `privacy.resistFingerprinting`
+      // pref is true.  We should at least not blow up.
+    }
+  }
+
+  /**
+   * _onVisibilityChange - If the visibility has changed to visible, sends a notification
+   *                      and removes the event listener. This should only be called once per tab.
+   */
+  _onVisibilityChange() {
+    if (this.document.visibilityState === VISIBLE) {
+      this._sendEvent();
+      this.document.removeEventListener(VISIBILITY_CHANGE_EVENT, this._onVisibilityChange);
+    }
+  }
+}