improved performance and battery usage on older devices

lib/view/pages/files/search/files_search_controller.dart

@@ -26,6 +26,14 @@ class FilesSearchController extends ChangeNotifier {
   Object? _serverError;
   int _serverEpoch = 0;
   bool _disposed = false;
+  Future<List<CacheableFile>>? _localIndex;
+
+  Future<List<CacheableFile>> _searchLocal(List<String> pathScope) async =>
+      searchLocalCacheIndex(
+        await (_localIndex ??= loadLocalCacheIndex()),
+        _query,
+        pathScope: pathScope,
+      );
 
   /// Guards against the race where the search delegate is closed (and the
   /// controller disposed) while a debounced cache scan or server call is
@@ -80,7 +88,7 @@ class FilesSearchController extends ChangeNotifier {
     _serverError = null;
     _safeNotify();
 
-    final cacheHits = await searchLocalCaches(_query, pathScope: _pathScope);
+    final cacheHits = await _searchLocal(_pathScope);
     if (epoch != _serverEpoch) return;
     _cacheResults = cacheHits;
     _safeNotify();
@@ -101,7 +109,7 @@ class FilesSearchController extends ChangeNotifier {
     _serverError = null;
     _safeNotify();
 
-    final cacheHits = await searchLocalCaches(_query);
+    final cacheHits = await _searchLocal(const []);
     if (epoch != _serverEpoch) return;
     _cacheResults = cacheHits;
     _safeNotify();