fixup! TB 40933: Add tor-launcher functionality

TB 42300: Store TorProvider log messages in TorProviderBuilder to be
used between instances and to be available whilst a provider is not
available.

toolkit/components/tor-launcher/TorProvider.sys.mjs

@@ -45,12 +45,6 @@ const logger = console.createInstance({
  * @property {string} [host] The host to connect for a TCP proxy
  * @property {number} [port] The port number to use for a TCP proxy
  */
-/**
- * @typedef {object} LogEntry An object with a log message
- * @property {string} timestamp The local date-time stamp at which we received the message
- * @property {string} type The message level
- * @property {string} msg The message
- */
 /**
  * Stores the data associated with a circuit node.
  *
@@ -69,7 +63,6 @@ const Preferences = Object.freeze({
   ControlUseIpc: "extensions.torlauncher.control_port_use_ipc",
   ControlHost: "extensions.torlauncher.control_host",
   ControlPort: "extensions.torlauncher.control_port",
-  MaxLogEntries: "extensions.torlauncher.max_tor_log_entries",
 });
 
 /* Config Keys used to configure tor daemon */
@@ -141,15 +134,6 @@ export class TorProvider {
    */
   #socksSettings = null;
 
-  /**
-   * The logs we received over the control port.
-   * We store a finite number of log entries which can be configured with
-   * extensions.torlauncher.max_tor_log_entries.
-   *
-   * @type {LogEntry[]}
-   */
-  #logs = [];
-
   #isBootstrapDone = false;
   /**
    * Keep the last warning to avoid broadcasting an async warning if it is the
@@ -511,15 +495,6 @@ export class TorProvider {
     return this.#controller.onionAuthViewKeys();
   }
 
-  /**
-   * Returns captured log messages.
-   *
-   * @returns {LogEntry[]} The logs we collected from the tor daemon so far.
-   */
-  getLog() {
-    return structuredClone(this.#logs);
-  }
-
   /**
    * @returns {boolean} true if we launched and control tor, false if we are
    * using system tor.
@@ -1033,15 +1008,6 @@ export class TorProvider {
       TorProviderTopics.TorLog
     );
 
-    const maxEntries = Services.prefs.getIntPref(
-      Preferences.MaxLogEntries,
-      1000
-    );
-    if (maxEntries > 0 && this.#logs.length >= maxEntries) {
-      this.#logs.splice(0, 1);
-    }
-
-    this.#logs.push({ type, msg, timestamp });
     switch (type) {
       case "ERR":
         logger.error(`[Tor error] ${msg}`);

toolkit/components/tor-launcher/TorProviderBuilder.sys.mjs

@@ -23,6 +23,13 @@ export const TorProviders = Object.freeze({
   tor: 1,
 });
 
+/**
+ * @typedef {object} LogEntry An object with a log message
+ * @property {string} timestamp The local date-time stamp at which we received the message
+ * @property {string} type The message level
+ * @property {string} msg The message
+ */
+
 /**
  * The factory to get a Tor provider.
  * Currently we support only TorProvider, i.e., the one that interacts with
@@ -36,6 +43,48 @@ export class TorProviderBuilder {
    */
   static #provider = null;
 
+  /**
+   * A record of the log messages from all TorProvider instances.
+   *
+   * @type {LogEntry[]}
+   */
+  static #log = [];
+
+  /**
+   * Get a record of historic log entries.
+   *
+   * @returns {LogEntry[]} - The record of entries.
+   */
+  static getLog() {
+    return structuredClone(this.#log);
+  }
+
+  /**
+   * The limit on the number of log entries we should store.
+   *
+   * @type {integer}
+   */
+  static #logLimit;
+
+  /**
+   * The observer that checks for new TorLog messages.
+   *
+   * @type {Function}
+   */
+  static #logObserver;
+
+  /**
+   * Add a new log message.
+   *
+   * @param {LogEntry} logEntry - The log entry to add.
+   */
+  static #addLogEntry(logEntry) {
+    if (this.#logLimit > 0 && this.#log.length >= this.#logLimit) {
+      this.#log.splice(0, 1);
+    }
+    this.#log.push(logEntry);
+  }
+
   /**
    * The observer that checks when the tor process exits, and reinitializes the
    * provider.
@@ -56,6 +105,15 @@ export class TorProviderBuilder {
    * Initialize the provider of choice.
    */
   static init() {
+    this.#logLimit = Services.prefs.getIntPref(
+      "extensions.torlauncher.max_tor_log_entries",
+      1000
+    );
+    this.#logObserver = subject => {
+      this.#addLogEntry(subject.wrappedJSObject);
+    };
+    Services.obs.addObserver(this.#logObserver, TorProviderTopics.TorLog);
+
     switch (this.providerType) {
       case TorProviders.tor:
         // Even though initialization of the initial TorProvider is
@@ -136,6 +194,7 @@ export class TorProviderBuilder {
       );
       this.#exitObserver = null;
     }
+    Services.obs.removeObserver(this.#logObserver, TorProviderTopics.TorLog);
   }
 
   /**