Add support to ObjectBox backend for root statistics

Removed v6 -> v7 migrator
Removed `RootManagement`

lib/flutter_map_tile_caching.dart

@@ -29,7 +29,6 @@ import 'package:isar/isar.dart';
 import 'package:latlong2/latlong.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
-import 'package:path_provider/path_provider.dart';
 import 'package:stream_transform/stream_transform.dart';
 import 'package:watcher/watcher.dart';
 
@@ -38,7 +37,6 @@ import 'src/bulk_download/instance.dart';
 import 'src/bulk_download/rate_limited_stream.dart';
 import 'src/bulk_download/tile_loops/shared.dart';
 import 'src/errors/browsing.dart';
-import 'src/misc/exts.dart';
 import 'src/misc/int_extremes.dart';
 import 'src/misc/obscure_query_params.dart';
 import 'src/providers/image_provider.dart';
@@ -64,7 +62,6 @@ part 'src/regions/recovered_region.dart';
 part 'src/regions/rectangle.dart';
 part 'src/root/directory.dart';
 part 'src/root/import.dart';
-part 'src/root/manage.dart';
 part 'src/root/migrator.dart';
 part 'src/root/recovery.dart';
 part 'src/root/statistics.dart';

lib/src/backend/impls/objectbox/backend.dart

@@ -89,7 +89,7 @@ class _ObjectBoxBackendImpl implements FMTCObjectBoxBackendInternal {
 
   Future<Map<String, dynamic>?> _sendCmd({
     required _WorkerCmdType type,
-    required Map<String, dynamic> args,
+    Map<String, dynamic> args = const {},
   }) async {
     expectInitialised;
 
@@ -199,6 +199,18 @@ class _ObjectBoxBackendImpl implements FMTCObjectBoxBackendInternal {
     FMTCBackendAccess.internal = null;
   }
 
+  @override
+  Future<List<String>> listStores() async =>
+      (await _sendCmd(type: _WorkerCmdType.storeExists))!['stores'];
+
+  @override
+  Future<double> rootSize() async =>
+      (await _sendCmd(type: _WorkerCmdType.rootSize))!['size'];
+
+  @override
+  Future<int> rootLength() async =>
+      (await _sendCmd(type: _WorkerCmdType.rootLength))!['length'];
+
   @override
   Future<bool> storeExists({
     required String storeName,

lib/src/backend/impls/objectbox/worker.dart

@@ -6,6 +6,9 @@ part of 'backend.dart';
 enum _WorkerCmdType {
   initialise_, // Only valid as a response
   destroy_, // Only valid as a request
+  listStores,
+  rootSize,
+  rootLength,
   storeExists,
   createStore,
   resetStore,
@@ -132,6 +135,41 @@ Future<void> _worker(
 
           // TODO: Consider final message
           Isolate.exit();
+        case _WorkerCmdType.listStores:
+          final query = root
+              .box<ObjectBoxStore>()
+              .query()
+              .build()
+              .property(ObjectBoxStore_.name);
+
+          sendRes(id: cmd.id, data: {'stores': query.find()});
+
+          query.close();
+
+          break;
+        case _WorkerCmdType.rootSize:
+          final query = root
+              .box<ObjectBoxStore>()
+              .query()
+              .build()
+              .property(ObjectBoxStore_.size);
+
+          sendRes(
+            id: cmd.id,
+            data: {'size': query.find().sum / 1024}, // Convert to KiB
+          );
+
+          query.close();
+
+          break;
+        case _WorkerCmdType.rootLength:
+          final query = root.box<ObjectBoxTile>().query().build();
+
+          sendRes(id: cmd.id, data: {'length': query.count()});
+
+          query.close();
+
+          break;
         case _WorkerCmdType.storeExists:
           final query = root
               .box<ObjectBoxStore>()

lib/src/backend/interfaces/backend.dart

@@ -70,6 +70,22 @@ abstract interface class FMTCBackendInternal with FMTCBackendAccess {
   /// initialised.
   Directory? get rootDirectory;
 
+  /// {@template fmtc.backend.listStores}
+  /// List all the available stores
+  /// {@endtemplate}
+  Future<List<String>> listStores();
+
+  /// {@template fmtc.backend.rootSize}
+  /// Retrieve the total number of KiBs of all tiles' bytes (not 'real total'
+  /// size) from all stores
+  /// {@endtemplate}
+  Future<double> rootSize();
+
+  /// {@template fmtc.backend.rootLength}
+  /// Retrieve the total number of tiles in all stores
+  /// {@endtemplate}
+  Future<int> rootLength();
+
   /// {@template fmtc.backend.storeExists}
   /// Check whether the specified store currently exists
   /// {@endtemplate}

lib/src/root/directory.dart

@@ -18,19 +18,16 @@ only. It will be removed in a future version.
 )
 typedef RootDirectory = FMTCRoot;
 
-/// Provides access to management, statistics, recovery, migration (and the
-/// import functionality) on the intitialised root.
+/// Provides access to statistics, recovery, migration (and the import
+/// functionality) on the intitialised root.
+///
+/// Management services are not provided here, instead use methods on the backend
+/// directly.
 ///
 /// Note that this does not provide direct access to any [FMTCStore]s.
 abstract class FMTCRoot {
   const FMTCRoot._();
 
-  /// Manage the root's representation on the filesystem
-  ///
-  /// To create, initialise FMTC. Assume that FMTC is ready after initialisation
-  /// and before [RootManagement.delete] is called.
-  static RootManagement get manage => const RootManagement._();
-
   /// Get statistics about this root (and all sub-stores)
   static RootStats get stats => const RootStats._();