1 files changed, 194 insertions, 0 deletions
diff --git a/toolkit/modules/BrowserTelemetryUtils.sys.mjs b/toolkit/modules/BrowserTelemetryUtils.sys.mjs
new file mode 100644
index 0000000000..bacd32686d
--- /dev/null
+++ b/toolkit/modules/BrowserTelemetryUtils.sys.mjs
@@ -0,0 +1,194 @@
+/* -*- mode: js; indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* 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/. */
+
+import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
+
+const lazy = {};
+
+// The maximum number of concurrently-loaded origins allowed in order to
+// qualify for the Fission rollout experiment.
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "fissionExperimentMaxOrigins",
+  "fission.experiment.max-origins.origin-cap",
+  30
+);
+// The length of the sliding window during which a user must stay below
+// the max origin cap. If the last time a user passed the max origin cap
+// fell outside of this window, they will requalify for the experiment.
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "fissionExperimentSlidingWindowMS",
+  "fission.experiment.max-origins.sliding-window-ms",
+  7 * 24 * 60 * 60 * 1000
+);
+// The pref holding the current qaualification state of the user. If
+// true, the user is currently qualified from the experiment.
+const FISSION_EXPERIMENT_PREF_QUALIFIED =
+  "fission.experiment.max-origins.qualified";
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "fissionExperimentQualified",
+  FISSION_EXPERIMENT_PREF_QUALIFIED,
+  false
+);
+// The pref holding the timestamp of the last time we saw an origin
+// count below the cap while the user was not currently marked as
+// qualified.
+const FISSION_EXPERIMENT_PREF_LAST_QUALIFIED =
+  "fission.experiment.max-origins.last-qualified";
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "fissionExperimentLastQualified",
+  FISSION_EXPERIMENT_PREF_LAST_QUALIFIED,
+  0
+);
+// The pref holding the timestamp of the last time we saw an origin
+// count exceeding the cap.
+const FISSION_EXPERIMENT_PREF_LAST_DISQUALIFIED =
+  "fission.experiment.max-origins.last-disqualified";
+XPCOMUtils.defineLazyPreferenceGetter(
+  lazy,
+  "fissionExperimentLastDisqualified",
+  FISSION_EXPERIMENT_PREF_LAST_DISQUALIFIED,
+  0
+);
+
+export var BrowserTelemetryUtils = {
+  recordSiteOriginTelemetry(aWindows, aIsGeckoView) {
+    Services.tm.idleDispatchToMainThread(() => {
+      this._recordSiteOriginTelemetry(aWindows, aIsGeckoView);
+    });
+  },
+
+  computeSiteOriginCount(aWindows, aIsGeckoView) {
+    // Geckoview and Desktop work differently. On desktop, aBrowser objects
+    // holds an array of tabs which we can use to get the <browser> objects.
+    // In Geckoview, it is apps' responsibility to keep track of the tabs, so
+    // there isn't an easy way for us to get the tabs.
+    let tabs = [];
+    if (aIsGeckoView) {
+      // To get all active windows; Each tab has its own window
+      tabs = aWindows;
+    } else {
+      for (const win of aWindows) {
+        tabs = tabs.concat(win.gBrowser.tabs);
+      }
+    }
+
+    let topLevelBCs = [];
+
+    for (const tab of tabs) {
+      let browser;
+      if (aIsGeckoView) {
+        browser = tab.browser;
+      } else {
+        browser = tab.linkedBrowser;
+      }
+
+      if (browser.browsingContext) {
+        // This is the top level browsingContext
+        topLevelBCs.push(browser.browsingContext);
+      }
+    }
+
+    return CanonicalBrowsingContext.countSiteOrigins(topLevelBCs);
+  },
+
+  _recordSiteOriginTelemetry(aWindows, aIsGeckoView) {
+    let currentTime = Date.now();
+
+    // default is 5 minutes
+    if (!this.min_interval) {
+      this.min_interval = Services.prefs.getIntPref(
+        "telemetry.number_of_site_origin.min_interval",
+        300000
+      );
+    }
+
+    let originCount = this.computeSiteOriginCount(aWindows, aIsGeckoView);
+    let histogram = Services.telemetry.getHistogramById(
+      "FX_NUMBER_OF_UNIQUE_SITE_ORIGINS_ALL_TABS"
+    );
+
+    // Discard the first load because most of the time the first load only has 1
+    // tab and 1 window open, so it is useless to report it.
+    if (!this._lastRecordSiteOrigin) {
+      this._lastRecordSiteOrigin = currentTime;
+    } else if (currentTime >= this._lastRecordSiteOrigin + this.min_interval) {
+      this._lastRecordSiteOrigin = currentTime;
+
+      histogram.add(originCount);
+    }
+
+    // Update the Fission experiment qualification state based on the
+    // current origin count:
+
+    // If we don't already have a last disqualification timestamp, look
+    // through the existing histogram values, and use the existing
+    // maximum value as the initial count. This will prevent us from
+    // enrolling users in the experiment if they have a history of
+    // exceeding our origin cap.
+    if (!this._checkedInitialExperimentQualification) {
+      this._checkedInitialExperimentQualification = true;
+      if (
+        !Services.prefs.prefHasUserValue(
+          FISSION_EXPERIMENT_PREF_LAST_DISQUALIFIED
+        )
+      ) {
+        for (let [bucketStr, entryCount] of Object.entries(
+          histogram.snapshot().values
+        )) {
+          let bucket = Number(bucketStr);
+          if (bucket > originCount && entryCount > 0) {
+            originCount = bucket;
+          }
+        }
+        Services.prefs.setIntPref(FISSION_EXPERIMENT_PREF_LAST_DISQUALIFIED, 0);
+      }
+    }
+
+    let currentTimeSec = currentTime / 1000;
+    if (originCount < lazy.fissionExperimentMaxOrigins) {
+      let lastDisqualified = lazy.fissionExperimentLastDisqualified;
+      let lastQualified = lazy.fissionExperimentLastQualified;
+
+      // If the last time we saw a qualifying origin count was earlier
+      // than the last time we say a disqualifying count, update any
+      // existing last disqualified timestamp to just before now, on the
+      // basis that our origin count has probably just fallen below the
+      // cap.
+      if (lastDisqualified > 0 && lastQualified <= lastDisqualified) {
+        Services.prefs.setIntPref(
+          FISSION_EXPERIMENT_PREF_LAST_DISQUALIFIED,
+          currentTimeSec - 1
+        );
+      }
+
+      if (!lazy.fissionExperimentQualified) {
+        Services.prefs.setIntPref(
+          FISSION_EXPERIMENT_PREF_LAST_QUALIFIED,
+          currentTimeSec
+        );
+
+        // We have a qualifying origin count now. If the last time we were
+        // disqualified was prior to the start of our current sliding
+        // window, re-qualify the user.
+        if (
+          currentTimeSec - lastDisqualified >=
+          lazy.fissionExperimentSlidingWindowMS / 1000
+        ) {
+          Services.prefs.setBoolPref(FISSION_EXPERIMENT_PREF_QUALIFIED, true);
+        }
+      }
+    } else {
+      Services.prefs.setIntPref(
+        FISSION_EXPERIMENT_PREF_LAST_DISQUALIFIED,
+        currentTimeSec
+      );
+      Services.prefs.setBoolPref(FISSION_EXPERIMENT_PREF_QUALIFIED, false);
+    }
+  },
+};