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lib/13/02/route/route_state.dart

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+// Copyright 2021, the Flutter project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:flutter/widgets.dart';
+
+import 'parsed_route.dart';
+import 'parser.dart';
+
+/// The current route state. To change the current route, call obtain the state
+/// using `RouteStateScope.of(context)` and call `go()`:
+///
+/// ```
+/// RouteStateScope.of(context).go('/book/2');
+/// ```
+class RouteState extends ChangeNotifier {
+  final AppRouteParser _parser;
+  ParsedRoute _route;
+
+  RouteState(this._parser) : _route = _parser.initialRoute;
+
+  ParsedRoute get route => _route;
+
+  set route(ParsedRoute route) {
+    // Don't notify listeners if the path hasn't changed.
+    if (_route == route) return;
+
+    _route = route;
+    notifyListeners();
+  }
+
+  Future<void> update(String route) async {
+    this.route = await _parser
+        .parseRouteInformation(RouteInformation(uri: Uri.parse(route)));
+  }
+}
+
+/// Provides the current [RouteState] to descendant widgets in the tree.
+class RouteStateScope extends InheritedNotifier<RouteState> {
+  const RouteStateScope({
+    required super.notifier,
+    required super.child,
+    super.key,
+  });
+
+  static RouteState of(BuildContext context) =>
+      context.dependOnInheritedWidgetOfExactType<RouteStateScope>()!.notifier!;
+}