fixup! Lox integration

Bug 42489: Require a loxId argument for most methods.

This ensures that a method only works on the credentials of the
*expected* loxId, rather than the newest `TorSettings.bridges.lox_id`
value which may change during a session.

We also add `#activeLoxId` to stay in sync with
`TorSettings.brigdes.lox_id`. We merge `clearInvites` into its updater.

toolkit/components/lox/Lox.sys.mjs

@@ -91,6 +91,40 @@ class LoxImpl {
   #events = [];
   #backgroundInterval = null;
 
+  /**
+   * The lox ID that is currently active.
+   *
+   * Stays in sync with TorSettings.bridges.lox_id. null when uninitialized.
+   *
+   * @type {string?}
+   */
+  #activeLoxId = null;
+
+  /**
+   * Update the active lox id.
+   */
+  #updateActiveLoxId() {
+    const loxId = lazy.TorSettings.bridges.lox_id;
+    if (loxId === this.#activeLoxId) {
+      return;
+    }
+    lazy.logger.debug(
+      `#activeLoxId switching from "${this.#activeLoxId}" to "${loxId}"`
+    );
+    if (this.#activeLoxId !== null) {
+      lazy.logger.debug(
+        `Clearing event data and invites for "${this.#activeLoxId}"`
+      );
+      // If not initializing clear the metadata for the old lox ID when it
+      // changes.
+      this.clearEventData(this.#activeLoxId);
+      // TODO: Do we want to keep invites? See tor-browser#42453
+      this.#invites = [];
+      this.#store();
+    }
+    this.#activeLoxId = loxId;
+  }
+
   observe(subject, topic, data) {
     switch (topic) {
       case lazy.TorSettingsTopics.SettingsChanged:
@@ -100,11 +134,8 @@ class LoxImpl {
           changes.includes("bridges.source") ||
           changes.includes("bridges.lox_id")
         ) {
-          // if lox_id has changed, clear event and invite queues
-          if (changes.includes("bridges.lox_id")) {
-            this.clearEventData();
-            this.clearInvites();
-          }
+          // The lox_id may have changed.
+          this.#updateActiveLoxId();
 
           // Only run background tasks if Lox is enabled
           if (this.#inuse) {
@@ -121,6 +152,8 @@ class LoxImpl {
         }
         break;
       case lazy.TorSettingsTopics.Ready:
+        // Set the initial #activeLoxId.
+        this.#updateActiveLoxId();
         // Run background tasks every 12 hours if Lox is enabled
         if (this.#inuse) {
           this.#backgroundInterval = setInterval(
@@ -134,9 +167,9 @@ class LoxImpl {
 
   get #inuse() {
     return (
+      Boolean(this.#activeLoxId) &&
       lazy.TorSettings.bridges.enabled === true &&
-      lazy.TorSettings.bridges.source === lazy.TorBridgeSource.Lox &&
-      lazy.TorSettings.bridges.lox_id
+      lazy.TorSettings.bridges.source === lazy.TorBridgeSource.Lox
     );
   }
 
@@ -318,7 +351,12 @@ class LoxImpl {
     if (!this.#initialized) {
       throw new LoxError(LoxErrors.NotInitialized);
     }
-    const loxId = lazy.TorSettings.bridges.lox_id;
+    // Only run background tasks for the active lox ID.
+    const loxId = this.#activeLoxId;
+    if (!loxId) {
+      lazy.logger.warn("No loxId for the background task");
+      return;
+    }
     try {
       const levelup = await this.#attemptUpgrade(loxId);
       if (levelup) {
@@ -490,14 +528,14 @@ class LoxImpl {
    *  - there is no saved Lox credential, or
    *  - the saved credential does not have any invitations available.
    *
+   * @param {string} loxId - The ID to generate an invite for.
    * @returns {string} A valid Lox invitation.
    */
-  async generateInvite() {
+  async generateInvite(loxId) {
     if (!this.#initialized) {
       throw new LoxError(LoxErrors.NotInitialized);
     }
-    const loxId = lazy.TorSettings.bridges.lox_id;
-    if (!loxId || !this.#credentials[loxId]) {
+    if (!this.#credentials[loxId]) {
       throw new LoxError(LoxErrors.MissingCredential);
     }
     await this.#getPubKeys();
@@ -538,15 +576,15 @@ class LoxImpl {
   /**
    * Get the number of invites that a user has remaining.
    *
+   * @param {string} loxId - The ID to check.
    * @returns {int} The number of invites that can still be generated by a
    *   user's credential.
    */
-  getRemainingInviteCount() {
+  getRemainingInviteCount(loxId) {
     if (!this.#initialized) {
       throw new LoxError(LoxErrors.NotInitialized);
     }
-    const loxId = lazy.TorSettings.bridges.lox_id;
-    if (!loxId || !this.#credentials[loxId]) {
+    if (!this.#credentials[loxId]) {
       throw new LoxError(LoxErrors.MissingCredential);
     }
     return parseInt(lazy.get_invites_remaining(this.#credentials[loxId]));
@@ -610,7 +648,7 @@ class LoxImpl {
     if (level < 1) {
       // attempt trust promotion instead
       try {
-        success = await this.#trustMigration();
+        success = await this.#trustMigration(loxId);
       } catch (err) {
         lazy.logger.error(err);
         return false;
@@ -640,14 +678,11 @@ class LoxImpl {
   /**
    * Attempt to migrate from an untrusted to a trusted Lox credential
    *
+   * @param {string} loxId - The ID to use.
    * @returns {Promise<bool>} A bool value indicated whether the credential
    *    was successfully migrated.
    */
-  async #trustMigration() {
-    const loxId = lazy.TorSettings.bridges.lox_id;
-    if (!loxId || !this.#credentials[loxId]) {
-      throw new LoxError(LoxErrors.MissingCredential);
-    }
+  async #trustMigration(loxId) {
     await this.#getPubKeys();
     return new Promise((resolve, reject) => {
       let request = "";
@@ -715,61 +750,68 @@ class LoxImpl {
   /**
    * Get a list of accumulated events.
    *
+   * @param {string} loxId - The ID to get events for.
    * @returns {EventData[]} A list of the accumulated, unacknowledged events
    *   associated with a user's credential.
    */
-  getEventData() {
+  getEventData(loxId) {
     if (!this.#initialized) {
       throw new LoxError(LoxErrors.NotInitialized);
     }
-    const loxId = lazy.TorSettings.bridges.lox_id;
-    if (!loxId || !this.#credentials[loxId]) {
-      throw new LoxError(LoxErrors.MissingCredential);
+    if (loxId !== this.#activeLoxId) {
+      lazy.logger.warn(
+        `No event data for loxId ${loxId} since it was replaced by ${
+          this.#activeLoxId
+        }`
+      );
+      return [];
     }
     return this.#events;
   }
 
   /**
    * Clears accumulated event data.
+   *
+   * Should be called whenever the user acknowledges the existing events.
+   *
+   * @param {string} loxId - The ID to clear events for.
    */
-  clearEventData() {
+  clearEventData(loxId) {
     if (!this.#initialized) {
       throw new LoxError(LoxErrors.NotInitialized);
     }
-    this.#events = [];
-    this.#store();
-  }
-
-  /**
-   * Clears accumulated invitations.
-   */
-  clearInvites() {
-    if (!this.#initialized) {
-      throw new LoxError(LoxErrors.NotInitialized);
+    if (loxId !== this.#activeLoxId) {
+      lazy.logger.warn(
+        `Not clearing event data for loxId ${loxId} since it was replaced by ${
+          this.#activeLoxId
+        }`
+      );
+      return;
     }
-    this.#invites = [];
+    this.#events = [];
     this.#store();
   }
 
   /**
    * @typedef {object} UnlockData
    *
-   * @property {string} date - The date-time for the next level up, formatted as YYYY-MM-DDTHH:mm:ssZ.
-   * @property {integer} nextLevel - The next level. Levels count from 0, so this will be 1 or greater.
-   *
+   * @property {string} date - The date-time for the next level up, formatted as
+   *   YYYY-MM-DDTHH:mm:ssZ.
+   * @property {integer} nextLevel - The next level. Levels count from 0, so
+   *   this will be 1 or greater.
    */
 
   /**
    * Get details about the next feature unlock.
    *
+   * @param {string} loxId - The ID to get the unlock for.
    * @returns {UnlockData} - Details about the next unlock.
    */
-  async getNextUnlock() {
+  async getNextUnlock(loxId) {
     if (!this.#initialized) {
       throw new LoxError(LoxErrors.NotInitialized);
     }
-    const loxId = lazy.TorSettings.bridges.lox_id;
-    if (!loxId || !this.#credentials[loxId]) {
+    if (!this.#credentials[loxId]) {
       throw new LoxError(LoxErrors.MissingCredential);
     }
     await this.#getConstants();