improved performance and battery usage on older devices

lib/model/account_data.dart

@@ -228,16 +228,25 @@ class AccountData {
   Future<void> _migrateAndLoad() async {
     await _migrateFromLegacyStorage();
     await _migrateKeychainAccessibility();
-    _username = await _secureStorage.read(key: _usernameField);
-    _password = await _secureStorage.read(key: _passwordField);
-    _isDemo = (await _secureStorage.read(key: _demoField)) == 'true';
-    _usesLoginFlow =
-        (await _secureStorage.read(key: _loginFlowField)) == 'true';
+    // Independent keystore reads, each a platform-channel round trip with
+    // decryption: issued together since this gates the first frame.
+    final (username, password, demo, loginFlow) = await (
+      _secureStorage.read(key: _usernameField),
+      _secureStorage.read(key: _passwordField),
+      _secureStorage.read(key: _demoField),
+      _secureStorage.read(key: _loginFlowField),
+    ).wait;
+    _username = username;
+    _password = password;
+    _isDemo = demo == 'true';
+    _usesLoginFlow = loginFlow == 'true';
     try {
-      _appPassword = await pushSecureStorage.read(key: _appPasswordField);
-      _appPasswordTalk = await pushSecureStorage.read(
-        key: _appPasswordTalkField,
-      );
+      final (appPassword, appPasswordTalk) = await (
+        pushSecureStorage.read(key: _appPasswordField),
+        pushSecureStorage.read(key: _appPasswordTalkField),
+      ).wait;
+      _appPassword = appPassword;
+      _appPasswordTalk = appPasswordTalk;
     } on Object {
       _appPassword = null;
       _appPasswordTalk = null;

lib/model/data_cleaner.dart

@@ -1,24 +1,8 @@
-import 'package:localstore/localstore.dart';
-
-import '../api/request_cache.dart';
+import '../api/cache_store.dart';
 
 class DataCleaner {
   static Future<void> cleanOldCache() async {
-    final cacheData = await Localstore.instance
-        .collection(RequestCache.collection)
-        .get();
-    cacheData?.forEach((key, value) async {
-      final lastUpdate = DateTime.fromMillisecondsSinceEpoch(
-        ((value['lastupdate'] as num?) ?? 0).toInt(),
-      );
-      if (DateTime.now()
-          .subtract(const Duration(days: 200))
-          .isAfter(lastUpdate)) {
-        await Localstore.instance
-            .collection(RequestCache.collection)
-            .doc(key.split('/').last)
-            .delete();
-      }
-    });
+    await CacheStore.deleteLegacyLocalstoreCache();
+    await CacheStore.instance.deleteOlderThan(const Duration(days: 200));
   }
 }

lib/model/session_wipe.dart

@@ -8,6 +8,7 @@ import 'package:hydrated_bloc/hydrated_bloc.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
+import '../api/cache_store.dart';
 import '../api/marianumcloud/talk/share_files_to_chat.dart';
 import '../background/widget_background_task.dart';
 import '../notification/notification_service.dart';
@@ -26,7 +27,6 @@ import '../state/app/modules/timetable/bloc/timetable_bloc.dart';
 import '../utils/app_paths.dart';
 import '../utils/downloads/download_manager.dart';
 import '../utils/file_clipboard.dart';
-import '../widget/debug/cache_view.dart';
 import '../widget_data/widget_sync.dart';
 
 /// Removes everything the signed-out account left on the device. Every step
@@ -98,7 +98,7 @@ abstract final class SessionWipe {
       await (await SharedPreferences.getInstance()).clear();
     });
     await _stepAsync('hydrated storage', HydratedBloc.storage.clear);
-    await _stepAsync('request cache', const CacheView().clear);
+    await _stepAsync('request cache', CacheStore.instance.clear);
     await _stepAsync('chat background', () async {
       final image = File(AppPaths.chatBackgroundImage);
       if (image.existsSync()) await image.delete();