Bug 1191912 - Part 1 - Move client id caching to ClientID.jsm. r=rvitillo

toolkit/components/telemetry/TelemetryController.jsm

@@ -678,7 +678,7 @@ let Impl = {
     // id from disk.
     // We try to cache it in prefs to avoid this, even though this may
     // lead to some stale client ids.
-    this._clientID = Preferences.get(PREF_CACHED_CLIENTID, null);
+    this._clientID = ClientID.getCachedClientID();
 
     // Delay full telemetry initialization to give the browser time to
     // run various late initializers. Otherwise our gathered memory
@@ -691,9 +691,8 @@ let Impl = {
 
         yield TelemetrySend.setup(this._testMode);
 
-        // Load the ClientID and update the cache.
+        // Load the ClientID.
         this._clientID = yield ClientID.getClientID();
-        Preferences.set(PREF_CACHED_CLIENTID, this._clientID);
 
         // Purge the pings archive by removing outdated pings. We don't wait for this
         // task to complete, but TelemetryStorage blocks on it during shutdown.

toolkit/modules/ClientID.jsm

@@ -11,6 +11,7 @@ const {classes: Cc, interfaces: Ci, results: Cr, utils: Cu} = Components;
 Cu.import("resource://gre/modules/osfile.jsm");
 Cu.import("resource://gre/modules/Task.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Preferences.jsm");
 
 XPCOMUtils.defineLazyModuleGetter(this, "CommonUtils",
                                   "resource://services-common/utils.js");
@@ -23,6 +24,8 @@ XPCOMUtils.defineLazyGetter(this, "gStateFilePath", () => {
   return OS.Path.join(gDatareportingPath, "state.json");
 });
 
+const PREF_CACHED_CLIENTID = "toolkit.telemetry.cachedClientID";
+
 this.ClientID = Object.freeze({
   /**
    * This returns a promise resolving to the the stable client ID we use for
@@ -35,6 +38,17 @@ this.ClientID = Object.freeze({
     return ClientIDImpl.getClientID();
   },
 
+/**
+   * Get the client id synchronously without hitting the disk.
+   * This returns:
+   *  - the current on-disk client id if it was already loaded
+   *  - the client id that we cached into preferences (if any)
+   *  - null otherwise
+   */
+  getCachedClientID: function() {
+    return ClientIDImpl.getCachedClientID();
+  },
+
   /**
    * Only used for testing. Invalidates the client ID so that it gets read
    * again from file.
@@ -71,6 +85,7 @@ let ClientIDImpl = {
       let state = yield CommonUtils.readJSON(gStateFilePath);
       if (state && 'clientID' in state && typeof(state.clientID) == 'string') {
         this._clientID = state.clientID;
+        Preferences.set(PREF_CACHED_CLIENTID, this._clientID);
         return this._clientID;
       }
     } catch (e) {
@@ -83,6 +98,7 @@ let ClientIDImpl = {
       let state = yield CommonUtils.readJSON(fhrStatePath);
       if (state && 'clientID' in state && typeof(state.clientID) == 'string') {
         this._clientID = state.clientID;
+        Preferences.set(PREF_CACHED_CLIENTID, this._clientID);
         this._saveClientID();
         return this._clientID;
       }
@@ -92,6 +108,7 @@ let ClientIDImpl = {
 
     // We dont have an id from FHR yet, generate a new ID.
     this._clientID = CommonUtils.generateUUID();
+    Preferences.set(PREF_CACHED_CLIENTID, this._clientID);
     this._saveClientIdTask = this._saveClientID();
 
     // Wait on persisting the id. Otherwise failure to save the ID would result in
@@ -130,6 +147,23 @@ let ClientIDImpl = {
     return Promise.resolve(this._clientID);
   },
 
+  /**
+   * Get the client id synchronously without hitting the disk.
+   * This returns:
+   *  - the current on-disk client id if it was already loaded
+   *  - the client id that we cached into preferences (if any)
+   *  - null otherwise
+   */
+  getCachedClientID: function() {
+    if (this._clientID) {
+      // Already loaded the client id from disk.
+      return this._clientID;
+    }
+
+    // Not yet loaded, return the cached client id if we have one.
+    return Preferences.get(PREF_CACHED_CLIENTID, null);
+  },
+
   /*
    * Resets the provider. This is for testing only.
    */