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diff --git a/toolkit/components/normandy/lib/PreferenceRollouts.sys.mjs b/toolkit/components/normandy/lib/PreferenceRollouts.sys.mjs
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+/* 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 { LogManager } from "resource://normandy/lib/LogManager.sys.mjs";
+
+const lazy = {};
+ChromeUtils.defineESModuleGetters(lazy, {
+  CleanupManager: "resource://normandy/lib/CleanupManager.sys.mjs",
+  IndexedDB: "resource://gre/modules/IndexedDB.sys.mjs",
+  PrefUtils: "resource://normandy/lib/PrefUtils.sys.mjs",
+  TelemetryEnvironment: "resource://gre/modules/TelemetryEnvironment.sys.mjs",
+  TelemetryEvents: "resource://normandy/lib/TelemetryEvents.sys.mjs",
+});
+
+const log = LogManager.getLogger("recipe-runner");
+
+/**
+ * PreferenceRollouts store info about an active or expired preference rollout.
+ * @typedef {object} PreferenceRollout
+ * @property {string} slug
+ *   Unique slug of the experiment
+ * @property {string} state
+ *   The current state of the rollout: "active", "rolled-back", "graduated".
+ *   Active means that Normandy is actively managing therollout. Rolled-back
+ *   means that the rollout was previously active, but has been rolled back for
+ *   this user. Graduated means that the built-in default now matches the
+ *   rollout value, and so Normandy is no longer managing the preference.
+ * @property {Array<PreferenceSpec>} preferences
+ *   An array of preferences specifications involved in the rollout.
+ */
+
+/**
+ * PreferenceSpec describe how a preference should change during a rollout.
+ * @typedef {object} PreferenceSpec
+ * @property {string} preferenceName
+ *   The preference to modify.
+ * @property {string} preferenceType
+ *   Type of the preference being set.
+ * @property {string|integer|boolean} value
+ *   The value to change the preference to.
+ * @property {string|integer|boolean} previousValue
+ *   The value the preference would have on the default branch if this rollout
+ *   were not active.
+ */
+
+const STARTUP_PREFS_BRANCH = "app.normandy.startupRolloutPrefs.";
+const DB_NAME = "normandy-preference-rollout";
+const STORE_NAME = "preference-rollouts";
+const DB_VERSION = 1;
+
+/**
+ * Create a new connection to the database.
+ */
+function openDatabase() {
+  return lazy.IndexedDB.open(DB_NAME, DB_VERSION, db => {
+    db.createObjectStore(STORE_NAME, {
+      keyPath: "slug",
+    });
+  });
+}
+
+/**
+ * Cache the database connection so that it is shared among multiple operations.
+ */
+let databasePromise;
+function getDatabase() {
+  if (!databasePromise) {
+    databasePromise = openDatabase();
+  }
+  return databasePromise;
+}
+
+/**
+ * Get a transaction for interacting with the rollout store.
+ *
+ * @param {IDBDatabase} db
+ * @param {String} mode Either "readonly" or "readwrite"
+ *
+ * NOTE: Methods on the store returned by this function MUST be called
+ * synchronously, otherwise the transaction with the store will expire.
+ * This is why the helper takes a database as an argument; if we fetched the
+ * database in the helper directly, the helper would be async and the
+ * transaction would expire before methods on the store were called.
+ */
+function getStore(db, mode) {
+  if (!mode) {
+    throw new Error("mode is required");
+  }
+  return db.objectStore(STORE_NAME, mode);
+}
+
+export var PreferenceRollouts = {
+  STATE_ACTIVE: "active",
+  STATE_ROLLED_BACK: "rolled-back",
+  STATE_GRADUATED: "graduated",
+
+  // A set of rollout slugs that are obsolete based on the code in this build of
+  // Firefox. This may include things like the preference no longer being
+  // applicable, or the feature changing in such a way that Normandy's automatic
+  // graduation system cannot detect that the rollout should hand off to the
+  // built-in code.
+  GRADUATION_SET: new Set([
+    "pref-webrender-intel-rollout-70-release",
+    "bug-1703186-rollout-http3-support-release-88-89",
+    "rollout-doh-nightly-rollout-to-all-us-desktop-users-nightly-74-80-bug-1613481",
+    "rollout-doh-beta-rollout-to-all-us-desktop-users-v2-beta-74-80-bug-1613489",
+    "rollout-doh-us-staged-rollout-to-all-us-desktop-users-release-73-77-bug-1586331",
+    "bug-1648229-rollout-comcast-steering-rollout-release-78-80",
+    "bug-1732206-rollout-fission-release-rollout-release-94-95",
+    "bug-1745237-rollout-fission-beta-96-97-rollout-beta-96-97",
+    "bug-1750601-rollout-doh-steering-in-canada-staggered-starting-for-release-97-98",
+    "bug-1758988-rollout-doh-enablment-to-new-countries-staggered-st-release-98-100",
+    "bug-1758818-rollout-enabling-doh-in-new-countries-staggered-sta-release-98-100",
+  ]),
+
+  /**
+   * Update the rollout database with changes that happened during early startup.
+   * @param {object} rolloutPrefsChanged Map from pref name to previous pref value
+   */
+  async recordOriginalValues(originalPreferences) {
+    for (const rollout of await this.getAllActive()) {
+      let shouldSaveRollout = false;
+
+      // Count the number of preferences in this rollout that are now redundant.
+      let prefMatchingDefaultCount = 0;
+
+      for (const prefSpec of rollout.preferences) {
+        const builtInDefault = originalPreferences[prefSpec.preferenceName];
+        if (prefSpec.value === builtInDefault) {
+          prefMatchingDefaultCount++;
+        }
+        // Store the current built-in default. That way, if the preference is
+        // rolled back during the current session (ie, until the browser is
+        // shut down), the correct value will be used.
+        if (prefSpec.previousValue !== builtInDefault) {
+          prefSpec.previousValue = builtInDefault;
+          shouldSaveRollout = true;
+        }
+      }
+
+      if (prefMatchingDefaultCount === rollout.preferences.length) {
+        // Firefox's builtin defaults have caught up to the rollout, making all
+        // of the rollout's changes redundant, so graduate the rollout.
+        await this.graduate(rollout, "all-prefs-match");
+        // `this.graduate` writes the rollout to the db, so we don't need to do it anymore.
+        shouldSaveRollout = false;
+      }
+
+      if (shouldSaveRollout) {
+        const db = await getDatabase();
+        await getStore(db, "readwrite").put(rollout);
+      }
+    }
+  },
+
+  async init() {
+    lazy.CleanupManager.addCleanupHandler(() => this.saveStartupPrefs());
+
+    for (const rollout of await this.getAllActive()) {
+      if (this.GRADUATION_SET.has(rollout.slug)) {
+        await this.graduate(rollout, "in-graduation-set");
+        continue;
+      }
+      lazy.TelemetryEnvironment.setExperimentActive(
+        rollout.slug,
+        rollout.state,
+        {
+          type: "normandy-prefrollout",
+        }
+      );
+    }
+  },
+
+  /**
+   * Test wrapper that temporarily replaces the stored rollout data with fake
+   * data for testing.
+   */
+  withTestMock({
+    graduationSet = new Set(),
+    rollouts: prefRollouts = [],
+  } = {}) {
+    return testFunction => {
+      return async args => {
+        let db = await getDatabase();
+        const oldData = await getStore(db, "readonly").getAll();
+        await getStore(db, "readwrite").clear();
+        await Promise.all(prefRollouts.map(r => this.add(r)));
+        const oldGraduationSet = this.GRADUATION_SET;
+        this.GRADUATION_SET = graduationSet;
+
+        try {
+          await testFunction({ ...args, prefRollouts });
+        } finally {
+          this.GRADUATION_SET = oldGraduationSet;
+          db = await getDatabase();
+          await getStore(db, "readwrite").clear();
+          const store = getStore(db, "readwrite");
+          await Promise.all(oldData.map(d => store.add(d)));
+        }
+      };
+    };
+  },
+
+  /**
+   * Add a new rollout
+   * @param {PreferenceRollout} rollout
+   */
+  async add(rollout) {
+    const db = await getDatabase();
+    return getStore(db, "readwrite").add(rollout);
+  },
+
+  /**
+   * Update an existing rollout
+   * @param {PreferenceRollout} rollout
+   * @throws If a matching rollout does not exist.
+   */
+  async update(rollout) {
+    if (!(await this.has(rollout.slug))) {
+      throw new Error(
+        `Tried to update ${rollout.slug}, but it doesn't already exist.`
+      );
+    }
+    const db = await getDatabase();
+    return getStore(db, "readwrite").put(rollout);
+  },
+
+  /**
+   * Update many existing rollouts. More efficient than calling `update` many
+   * times in a row.
+   * @param {Array<PreferenceRollout>} rollouts
+   * @throws If any of the passed rollouts have a slug that doesn't exist in the database already.
+   */
+  async updateMany(rollouts) {
+    // Don't touch the database if there is nothing to do
+    if (!rollouts.length) {
+      return;
+    }
+
+    // Both of the below operations use .map() instead of a normal loop becaues
+    // once we get the object store, we can't let it expire by spinning the
+    // event loop. This approach queues up all the interactions with the store
+    // immediately, preventing it from expiring too soon.
+
+    const db = await getDatabase();
+    let store = await getStore(db, "readonly");
+    await Promise.all(
+      rollouts.map(async ({ slug }) => {
+        let existingRollout = await store.get(slug);
+        if (!existingRollout) {
+          throw new Error(`Tried to update ${slug}, but it doesn't exist.`);
+        }
+      })
+    );
+
+    // awaiting spun the event loop, so the store is now invalid. Get a new
+    // store. This is also a chance to get it in readwrite mode.
+    store = await getStore(db, "readwrite");
+    await Promise.all(rollouts.map(rollout => store.put(rollout)));
+  },
+
+  /**
+   * Test whether there is a rollout in storage with the given slug.
+   * @param {string} slug
+   * @returns {boolean}
+   */
+  async has(slug) {
+    const db = await getDatabase();
+    const rollout = await getStore(db, "readonly").get(slug);
+    return !!rollout;
+  },
+
+  /**
+   * Get a rollout by slug
+   * @param {string} slug
+   */
+  async get(slug) {
+    const db = await getDatabase();
+    return getStore(db, "readonly").get(slug);
+  },
+
+  /** Get all rollouts in the database. */
+  async getAll() {
+    const db = await getDatabase();
+    return getStore(db, "readonly").getAll();
+  },
+
+  /** Get all rollouts in the "active" state. */
+  async getAllActive() {
+    const rollouts = await this.getAll();
+    return rollouts.filter(rollout => rollout.state === this.STATE_ACTIVE);
+  },
+
+  /**
+   * Save in-progress preference rollouts in a sub-branch of the normandy prefs.
+   * On startup, we read these to set the rollout values.
+   */
+  async saveStartupPrefs() {
+    const prefBranch = Services.prefs.getBranch(STARTUP_PREFS_BRANCH);
+    for (const pref of prefBranch.getChildList("")) {
+      prefBranch.clearUserPref(pref);
+    }
+
+    for (const rollout of await this.getAllActive()) {
+      for (const prefSpec of rollout.preferences) {
+        lazy.PrefUtils.setPref(
+          STARTUP_PREFS_BRANCH + prefSpec.preferenceName,
+          prefSpec.value
+        );
+      }
+    }
+  },
+
+  async graduate(rollout, reason) {
+    log.debug(`Graduating rollout: ${rollout.slug}`);
+    rollout.state = this.STATE_GRADUATED;
+    const db = await getDatabase();
+    await getStore(db, "readwrite").put(rollout);
+    lazy.TelemetryEvents.sendEvent(
+      "graduate",
+      "preference_rollout",
+      rollout.slug,
+      {
+        reason,
+      }
+    );
+  },
+};