packages/go_router/lib/src/configuration.dart - mirrors/packages - Git at Google

 // Copyright 2013 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:async';

 import 'package:flutter/widgets.dart';

 import 'configuration.dart';
 import 'logging.dart';
 import 'match.dart';
 import 'misc/errors.dart';
 import 'path_utils.dart';
 import 'typedefs.dart';
 export 'route.dart';
 export 'state.dart';

 /// The route configuration for GoRouter configured by the app.
 class RouteConfiguration {
   /// Constructs a [RouteConfiguration].
   RouteConfiguration({
     required this.routes,
     required this.redirectLimit,
     required this.topRedirect,
     required this.navigatorKey,
   })  : assert(_debugCheckPath(routes, true)),
         assert(
             _debugVerifyNoDuplicatePathParameter(routes, <String, GoRoute>{})),
         assert(_debugCheckParentNavigatorKeys(
             routes, <GlobalKey<NavigatorState>>[navigatorKey])) {
     assert(_debugCheckStatefulShellBranchDefaultLocations(routes));
     _cacheNameToPath('', routes);
     log.info(debugKnownRoutes());
   }

   static bool _debugCheckPath(List<RouteBase> routes, bool isTopLevel) {
     for (final RouteBase route in routes) {
       late bool subRouteIsTopLevel;
       if (route is GoRoute) {
         if (isTopLevel) {
           if (!route.path.startsWith('/')) {
             throw GoError('top-level path must start with "/": $route');
           }
         } else {
           if (route.path.startsWith('/') || route.path.endsWith('/')) {
             throw GoError('sub-route path may not start or end with /: $route');
           }
         }
         subRouteIsTopLevel = false;
       } else if (route is ShellRouteBase) {
         subRouteIsTopLevel = isTopLevel;
       }
       _debugCheckPath(route.routes, subRouteIsTopLevel);
     }
     return true;
   }

   // Check that each parentNavigatorKey refers to either a ShellRoute's
   // navigatorKey or the root navigator key.
   static bool _debugCheckParentNavigatorKeys(
       List<RouteBase> routes, List<GlobalKey<NavigatorState>> allowedKeys) {
     for (final RouteBase route in routes) {
       if (route is GoRoute) {
         final GlobalKey<NavigatorState>? parentKey = route.parentNavigatorKey;
         if (parentKey != null) {
           // Verify that the root navigator or a ShellRoute ancestor has a
           // matching navigator key.
           if (!allowedKeys.contains(parentKey)) {
             throw GoError('parentNavigatorKey $parentKey must refer to'
                 " an ancestor ShellRoute's navigatorKey or GoRouter's"
                 ' navigatorKey');
           }

           _debugCheckParentNavigatorKeys(
             route.routes,
             <GlobalKey<NavigatorState>>[
               // Once a parentNavigatorKey is used, only that navigator key
               // or keys above it can be used.
               ...allowedKeys.sublist(0, allowedKeys.indexOf(parentKey) + 1),
             ],
           );
         } else {
           _debugCheckParentNavigatorKeys(
             route.routes,
             <GlobalKey<NavigatorState>>[
               ...allowedKeys,
             ],
           );
         }
       } else if (route is ShellRoute) {
         _debugCheckParentNavigatorKeys(
           route.routes,
           <GlobalKey<NavigatorState>>[...allowedKeys..add(route.navigatorKey)],
         );
       } else if (route is StatefulShellRoute) {
         for (final StatefulShellBranch branch in route.branches) {
           if (allowedKeys.contains(branch.navigatorKey)) {
             throw GoError(
                 'StatefulShellBranch must not reuse an ancestor navigatorKey '
                 '(${branch.navigatorKey})');
           }

           _debugCheckParentNavigatorKeys(
             branch.routes,
             <GlobalKey<NavigatorState>>[
               ...allowedKeys,
               branch.navigatorKey,
             ],
           );
         }
       }
     }
     return true;
   }

   static bool _debugVerifyNoDuplicatePathParameter(
       List<RouteBase> routes, Map<String, GoRoute> usedPathParams) {
     for (final RouteBase route in routes) {
       if (route is! GoRoute) {
         continue;
       }
       for (final String pathParam in route.pathParameters) {
         if (usedPathParams.containsKey(pathParam)) {
           final bool sameRoute = usedPathParams[pathParam] == route;
           throw GoError(
               "duplicate path parameter, '$pathParam' found in ${sameRoute ? '$route' : '${usedPathParams[pathParam]}, and $route'}");
         }
         usedPathParams[pathParam] = route;
       }
       _debugVerifyNoDuplicatePathParameter(route.routes, usedPathParams);
       route.pathParameters.forEach(usedPathParams.remove);
     }
     return true;
   }

   // Check to see that the configured initialLocation of StatefulShellBranches
   // points to a descendant route of the route branch.
   bool _debugCheckStatefulShellBranchDefaultLocations(List<RouteBase> routes) {
     for (final RouteBase route in routes) {
       if (route is StatefulShellRoute) {
         for (final StatefulShellBranch branch in route.branches) {
           if (branch.initialLocation == null) {
             // Recursively search for the first GoRoute descendant. Will
             // throw assertion error if not found.
             final GoRoute? route = branch.defaultRoute;
             final String? initialLocation =
                 route != null ? locationForRoute(route) : null;
             if (initialLocation == null) {
               throw GoError(
                   'The default location of a StatefulShellBranch must be '
                   'derivable from GoRoute descendant');
             }
             if (route!.pathParameters.isNotEmpty) {
               throw GoError(
                   'The default location of a StatefulShellBranch cannot be '
                   'a parameterized route');
             }
           } else {
             final RouteMatchList matchList = findMatch(branch.initialLocation!);
             if (matchList.isError) {
               throw GoError(
                   'initialLocation (${matchList.uri}) of StatefulShellBranch must '
                   'be a valid location');
             }
             final List<RouteBase> matchRoutes = matchList.routes;
             final int shellIndex = matchRoutes.indexOf(route);
             bool matchFound = false;
             if (shellIndex >= 0 && (shellIndex + 1) < matchRoutes.length) {
               final RouteBase branchRoot = matchRoutes[shellIndex + 1];
               matchFound = branch.routes.contains(branchRoot);
             }
             if (!matchFound) {
               throw GoError(
                   'The initialLocation (${branch.initialLocation}) of '
                   'StatefulShellBranch must match a descendant route of the '
                   'branch');
             }
           }
         }
       }
       _debugCheckStatefulShellBranchDefaultLocations(route.routes);
     }
     return true;
   }

   /// The match used when there is an error during parsing.
   static RouteMatchList _errorRouteMatchList(Uri uri, String errorMessage) {
     final Exception error = Exception(errorMessage);
     return RouteMatchList(
       matches: const <RouteMatch>[],
       error: error,
       uri: uri,
       pathParameters: const <String, String>{},
     );
   }

   /// The list of top level routes used by [GoRouterDelegate].
   final List<RouteBase> routes;

   /// The limit for the number of consecutive redirects.
   final int redirectLimit;

   /// The global key for top level navigator.
   final GlobalKey<NavigatorState> navigatorKey;

   /// Top level page redirect.
   final GoRouterRedirect topRedirect;

   final Map<String, String> _nameToPath = <String, String>{};

   /// Looks up the url location by a [GoRoute]'s name.
   String namedLocation(
     String name, {
     Map<String, String> pathParameters = const <String, String>{},
     Map<String, dynamic> queryParameters = const <String, dynamic>{},
   }) {
     assert(() {
       log.info('getting location for name: '
           '"$name"'
           '${pathParameters.isEmpty ? '' : ', pathParameters: $pathParameters'}'
           '${queryParameters.isEmpty ? '' : ', queryParameters: $queryParameters'}');
       return true;
     }());
     final String keyName = name.toLowerCase();
     assert(_nameToPath.containsKey(keyName), 'unknown route name: $name');
     final String path = _nameToPath[keyName]!;
     assert(() {
       // Check that all required params are present
       final List<String> paramNames = <String>[];
       patternToRegExp(path, paramNames);
       for (final String paramName in paramNames) {
         assert(pathParameters.containsKey(paramName),
             'missing param "$paramName" for $path');
       }

       // Check that there are no extra params
       for (final String key in pathParameters.keys) {
         assert(paramNames.contains(key), 'unknown param "$key" for $path');
       }
       return true;
     }());
     final Map<String, String> encodedParams = <String, String>{
       for (final MapEntry<String, String> param in pathParameters.entries)
         param.key: Uri.encodeComponent(param.value)
     };
     final String location = patternToPath(path, encodedParams);
     return Uri(
             path: location,
             queryParameters: queryParameters.isEmpty ? null : queryParameters)
         .toString();
   }

   /// Finds the routes that matched the given URL.
   RouteMatchList findMatch(String location, {Object? extra}) {
     final Uri uri = Uri.parse(canonicalUri(location));

     final Map<String, String> pathParameters = <String, String>{};
     final List<RouteMatch>? matches = _getLocRouteMatches(uri, pathParameters);

     if (matches == null) {
       return _errorRouteMatchList(uri, 'no routes for location: $uri');
     }
     return RouteMatchList(
         matches: matches,
         uri: uri,
         pathParameters: pathParameters,
         extra: extra);
   }

   List<RouteMatch>? _getLocRouteMatches(
       Uri uri, Map<String, String> pathParameters) {
     final List<RouteMatch>? result = _getLocRouteRecursively(
       location: uri.path,
       remainingLocation: uri.path,
       matchedLocation: '',
       pathParameters: pathParameters,
       routes: routes,
     );
     return result;
   }

   List<RouteMatch>? _getLocRouteRecursively({
     required String location,
     required String remainingLocation,
     required String matchedLocation,
     required Map<String, String> pathParameters,
     required List<RouteBase> routes,
   }) {
     List<RouteMatch>? result;
     late Map<String, String> subPathParameters;
     // find the set of matches at this level of the tree
     for (final RouteBase route in routes) {
       subPathParameters = <String, String>{};

       final RouteMatch? match = RouteMatch.match(
         route: route,
         remainingLocation: remainingLocation,
         matchedLocation: matchedLocation,
         pathParameters: subPathParameters,
       );

       if (match == null) {
         continue;
       }

       if (match.route is GoRoute &&
           match.matchedLocation.toLowerCase() == location.toLowerCase()) {
         // If it is a complete match, then return the matched route
         // NOTE: need a lower case match because matchedLocation is canonicalized to match
         // the path case whereas the location can be of any case and still match
         result = <RouteMatch>[match];
       } else if (route.routes.isEmpty) {
         // If it is partial match but no sub-routes, bail.
         continue;
       } else {
         // Otherwise, recurse
         final String childRestLoc;
         final String newParentSubLoc;
         if (match.route is ShellRouteBase) {
           childRestLoc = remainingLocation;
           newParentSubLoc = matchedLocation;
         } else {
           assert(location.startsWith(match.matchedLocation));
           assert(remainingLocation.isNotEmpty);

           childRestLoc = location.substring(match.matchedLocation.length +
               (match.matchedLocation == '/' ? 0 : 1));
           newParentSubLoc = match.matchedLocation;
         }

         final List<RouteMatch>? subRouteMatch = _getLocRouteRecursively(
           location: location,
           remainingLocation: childRestLoc,
           matchedLocation: newParentSubLoc,
           pathParameters: subPathParameters,
           routes: route.routes,
         );

         // If there's no sub-route matches, there is no match for this location
         if (subRouteMatch == null) {
           continue;
         }
         result = <RouteMatch>[match, ...subRouteMatch];
       }
       // Should only reach here if there is a match.
       break;
     }
     if (result != null) {
       pathParameters.addAll(subPathParameters);
     }
     return result;
   }

   /// Processes redirects by returning a new [RouteMatchList] representing the new
   /// location.
   FutureOr<RouteMatchList> redirect(
       BuildContext context, FutureOr<RouteMatchList> prevMatchListFuture,
       {required List<RouteMatchList> redirectHistory}) {
     FutureOr<RouteMatchList> processRedirect(RouteMatchList prevMatchList) {
       final String prevLocation = prevMatchList.uri.toString();
       FutureOr<RouteMatchList> processTopLevelRedirect(
           String? topRedirectLocation) {
         if (topRedirectLocation != null &&
             topRedirectLocation != prevLocation) {
           final RouteMatchList newMatch = _getNewMatches(
             topRedirectLocation,
             prevMatchList.uri,
             redirectHistory,
           );
           if (newMatch.isError) {
             return newMatch;
           }
           return redirect(
             context,
             newMatch,
             redirectHistory: redirectHistory,
           );
         }

         FutureOr<RouteMatchList> processRouteLevelRedirect(
             String? routeRedirectLocation) {
           if (routeRedirectLocation != null &&
               routeRedirectLocation != prevLocation) {
             final RouteMatchList newMatch = _getNewMatches(
               routeRedirectLocation,
               prevMatchList.uri,
               redirectHistory,
             );

             if (newMatch.isError) {
               return newMatch;
             }
             return redirect(
               context,
               newMatch,
               redirectHistory: redirectHistory,
             );
           }
           return prevMatchList;
         }

         final FutureOr<String?> routeLevelRedirectResult =
             _getRouteLevelRedirect(context, prevMatchList, 0);
         if (routeLevelRedirectResult is String?) {
           return processRouteLevelRedirect(routeLevelRedirectResult);
         }
         return routeLevelRedirectResult
             .then<RouteMatchList>(processRouteLevelRedirect);
       }

       redirectHistory.add(prevMatchList);
       // Check for top-level redirect
       final FutureOr<String?> topRedirectResult = topRedirect(
         context,
         GoRouterState(
           this,
           location: prevLocation,
           name: null,
           // No name available at the top level trim the query params off the
           // sub-location to match route.redirect
           matchedLocation: prevMatchList.uri.path,
           queryParameters: prevMatchList.uri.queryParameters,
           queryParametersAll: prevMatchList.uri.queryParametersAll,
           extra: prevMatchList.extra,
           pageKey: const ValueKey<String>('topLevel'),
         ),
       );

       if (topRedirectResult is String?) {
         return processTopLevelRedirect(topRedirectResult);
       }
       return topRedirectResult.then<RouteMatchList>(processTopLevelRedirect);
     }

     if (prevMatchListFuture is RouteMatchList) {
       return processRedirect(prevMatchListFuture);
     }
     return prevMatchListFuture.then<RouteMatchList>(processRedirect);
   }

   FutureOr<String?> _getRouteLevelRedirect(
     BuildContext context,
     RouteMatchList matchList,
     int currentCheckIndex,
   ) {
     if (currentCheckIndex >= matchList.matches.length) {
       return null;
     }
     final RouteMatch match = matchList.matches[currentCheckIndex];
     FutureOr<String?> processRouteRedirect(String? newLocation) =>
         newLocation ??
         _getRouteLevelRedirect(context, matchList, currentCheckIndex + 1);
     final RouteBase route = match.route;
     FutureOr<String?> routeRedirectResult;
     if (route is GoRoute && route.redirect != null) {
       routeRedirectResult = route.redirect!(
         context,
         GoRouterState(
           this,
           location: matchList.uri.toString(),
           matchedLocation: match.matchedLocation,
           name: route.name,
           path: route.path,
           fullPath: matchList.fullPath,
           extra: matchList.extra,
           pathParameters: matchList.pathParameters,
           queryParameters: matchList.uri.queryParameters,
           queryParametersAll: matchList.uri.queryParametersAll,
           pageKey: match.pageKey,
         ),
       );
     }
     if (routeRedirectResult is String?) {
       return processRouteRedirect(routeRedirectResult);
     }
     return routeRedirectResult.then<String?>(processRouteRedirect);
   }

   RouteMatchList _getNewMatches(
     String newLocation,
     Uri previousLocation,
     List<RouteMatchList> redirectHistory,
   ) {
     try {
       final RouteMatchList newMatch = findMatch(newLocation);
       _addRedirect(redirectHistory, newMatch, previousLocation);
       return newMatch;
     } on RedirectionError catch (e) {
       log.info('Redirection error: ${e.message}');
       return _errorRouteMatchList(e.location, e.message);
     }
   }

   /// Adds the redirect to [redirects] if it is valid.
   ///
   /// Throws if a loop is detected or the redirection limit is reached.
   void _addRedirect(
     List<RouteMatchList> redirects,
     RouteMatchList newMatch,
     Uri prevLocation,
   ) {
     if (redirects.contains(newMatch)) {
       throw RedirectionError('redirect loop detected',
           <RouteMatchList>[...redirects, newMatch], prevLocation);
     }
     if (redirects.length > redirectLimit) {
       throw RedirectionError('too many redirects',
           <RouteMatchList>[...redirects, newMatch], prevLocation);
     }

     redirects.add(newMatch);

     log.info('redirecting to $newMatch');
   }

   /// Get the location for the provided route.
   ///
   /// Builds the absolute path for the route, by concatenating the paths of the
   /// route and all its ancestors.
   String? locationForRoute(RouteBase route) =>
       fullPathForRoute(route, '', routes);

   @override
   String toString() {
     return 'RouterConfiguration: $routes';
   }

   /// Returns the full path of [routes].
   ///
   /// Each path is indented based depth of the hierarchy, and its `name`
   /// is also appended if not null
   @visibleForTesting
   String debugKnownRoutes() {
     final StringBuffer sb = StringBuffer();
     sb.writeln('Full paths for routes:');
     _debugFullPathsFor(routes, '', 0, sb);

     if (_nameToPath.isNotEmpty) {
       sb.writeln('known full paths for route names:');
       for (final MapEntry<String, String> e in _nameToPath.entries) {
         sb.writeln('  ${e.key} => ${e.value}');
       }
     }

     return sb.toString();
   }

   void _debugFullPathsFor(List<RouteBase> routes, String parentFullpath,
       int depth, StringBuffer sb) {
     for (final RouteBase route in routes) {
       if (route is GoRoute) {
         final String fullPath = concatenatePaths(parentFullpath, route.path);
         sb.writeln('  => ${''.padLeft(depth * 2)}$fullPath');
         _debugFullPathsFor(route.routes, fullPath, depth + 1, sb);
       } else if (route is ShellRoute) {
         _debugFullPathsFor(route.routes, parentFullpath, depth, sb);
       }
     }
   }

   void _cacheNameToPath(String parentFullPath, List<RouteBase> childRoutes) {
     for (final RouteBase route in childRoutes) {
       if (route is GoRoute) {
         final String fullPath = concatenatePaths(parentFullPath, route.path);

         if (route.name != null) {
           final String name = route.name!.toLowerCase();
           assert(
               !_nameToPath.containsKey(name),
               'duplication fullpaths for name '
               '"$name":${_nameToPath[name]}, $fullPath');
           _nameToPath[name] = fullPath;
         }

         if (route.routes.isNotEmpty) {
           _cacheNameToPath(fullPath, route.routes);
         }
       } else if (route is ShellRouteBase) {
         if (route.routes.isNotEmpty) {
           _cacheNameToPath(parentFullPath, route.routes);
         }
       }
     }
   }
 }
	// Copyright 2013 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:async';

	import 'package:flutter/widgets.dart';

	import 'configuration.dart';
	import 'logging.dart';
	import 'match.dart';
	import 'misc/errors.dart';
	import 'path_utils.dart';
	import 'typedefs.dart';
	export 'route.dart';
	export 'state.dart';

	/// The route configuration for GoRouter configured by the app.
	class RouteConfiguration {
	/// Constructs a [RouteConfiguration].
	RouteConfiguration({
	required this.routes,
	required this.redirectLimit,
	required this.topRedirect,
	required this.navigatorKey,
	}) : assert(_debugCheckPath(routes, true)),
	assert(
	_debugVerifyNoDuplicatePathParameter(routes, <String, GoRoute>{})),
	assert(_debugCheckParentNavigatorKeys(
	routes, <GlobalKey<NavigatorState>>[navigatorKey])) {
	assert(_debugCheckStatefulShellBranchDefaultLocations(routes));
	_cacheNameToPath('', routes);
	log.info(debugKnownRoutes());
	}

	static bool _debugCheckPath(List<RouteBase> routes, bool isTopLevel) {
	for (final RouteBase route in routes) {
	late bool subRouteIsTopLevel;
	if (route is GoRoute) {
	if (isTopLevel) {
	if (!route.path.startsWith('/')) {
	throw GoError('top-level path must start with "/": $route');
	}
	} else {
	if (route.path.startsWith('/') \|\| route.path.endsWith('/')) {
	throw GoError('sub-route path may not start or end with /: $route');
	}
	}
	subRouteIsTopLevel = false;
	} else if (route is ShellRouteBase) {
	subRouteIsTopLevel = isTopLevel;
	}
	_debugCheckPath(route.routes, subRouteIsTopLevel);
	}
	return true;
	}

	// Check that each parentNavigatorKey refers to either a ShellRoute's
	// navigatorKey or the root navigator key.
	static bool _debugCheckParentNavigatorKeys(
	List<RouteBase> routes, List<GlobalKey<NavigatorState>> allowedKeys) {
	for (final RouteBase route in routes) {
	if (route is GoRoute) {
	final GlobalKey<NavigatorState>? parentKey = route.parentNavigatorKey;
	if (parentKey != null) {
	// Verify that the root navigator or a ShellRoute ancestor has a
	// matching navigator key.
	if (!allowedKeys.contains(parentKey)) {
	throw GoError('parentNavigatorKey $parentKey must refer to'
	" an ancestor ShellRoute's navigatorKey or GoRouter's"
	' navigatorKey');
	}

	_debugCheckParentNavigatorKeys(
	route.routes,
	<GlobalKey<NavigatorState>>[
	// Once a parentNavigatorKey is used, only that navigator key
	// or keys above it can be used.
	...allowedKeys.sublist(0, allowedKeys.indexOf(parentKey) + 1),
	],
	);
	} else {
	_debugCheckParentNavigatorKeys(
	route.routes,
	<GlobalKey<NavigatorState>>[
	...allowedKeys,
	],
	);
	}
	} else if (route is ShellRoute) {
	_debugCheckParentNavigatorKeys(
	route.routes,
	<GlobalKey<NavigatorState>>[...allowedKeys..add(route.navigatorKey)],
	);
	} else if (route is StatefulShellRoute) {
	for (final StatefulShellBranch branch in route.branches) {
	if (allowedKeys.contains(branch.navigatorKey)) {
	throw GoError(
	'StatefulShellBranch must not reuse an ancestor navigatorKey '
	'(${branch.navigatorKey})');
	}

	_debugCheckParentNavigatorKeys(
	branch.routes,
	<GlobalKey<NavigatorState>>[
	...allowedKeys,
	branch.navigatorKey,
	],
	);
	}
	}
	}
	return true;
	}

	static bool _debugVerifyNoDuplicatePathParameter(
	List<RouteBase> routes, Map<String, GoRoute> usedPathParams) {
	for (final RouteBase route in routes) {
	if (route is! GoRoute) {
	continue;
	}
	for (final String pathParam in route.pathParameters) {
	if (usedPathParams.containsKey(pathParam)) {
	final bool sameRoute = usedPathParams[pathParam] == route;
	throw GoError(
	"duplicate path parameter, '$pathParam' found in ${sameRoute ? '$route' : '${usedPathParams[pathParam]}, and $route'}");
	}
	usedPathParams[pathParam] = route;
	}
	_debugVerifyNoDuplicatePathParameter(route.routes, usedPathParams);
	route.pathParameters.forEach(usedPathParams.remove);
	}
	return true;
	}

	// Check to see that the configured initialLocation of StatefulShellBranches
	// points to a descendant route of the route branch.
	bool _debugCheckStatefulShellBranchDefaultLocations(List<RouteBase> routes) {
	for (final RouteBase route in routes) {
	if (route is StatefulShellRoute) {
	for (final StatefulShellBranch branch in route.branches) {
	if (branch.initialLocation == null) {
	// Recursively search for the first GoRoute descendant. Will
	// throw assertion error if not found.
	final GoRoute? route = branch.defaultRoute;
	final String? initialLocation =
	route != null ? locationForRoute(route) : null;
	if (initialLocation == null) {
	throw GoError(
	'The default location of a StatefulShellBranch must be '
	'derivable from GoRoute descendant');
	}
	if (route!.pathParameters.isNotEmpty) {
	throw GoError(
	'The default location of a StatefulShellBranch cannot be '
	'a parameterized route');
	}
	} else {
	final RouteMatchList matchList = findMatch(branch.initialLocation!);
	if (matchList.isError) {
	throw GoError(
	'initialLocation (${matchList.uri}) of StatefulShellBranch must '
	'be a valid location');
	}
	final List<RouteBase> matchRoutes = matchList.routes;
	final int shellIndex = matchRoutes.indexOf(route);
	bool matchFound = false;
	if (shellIndex >= 0 && (shellIndex + 1) < matchRoutes.length) {
	final RouteBase branchRoot = matchRoutes[shellIndex + 1];
	matchFound = branch.routes.contains(branchRoot);
	}
	if (!matchFound) {
	throw GoError(
	'The initialLocation (${branch.initialLocation}) of '
	'StatefulShellBranch must match a descendant route of the '
	'branch');
	}
	}
	}
	}
	_debugCheckStatefulShellBranchDefaultLocations(route.routes);
	}
	return true;
	}

	/// The match used when there is an error during parsing.
	static RouteMatchList _errorRouteMatchList(Uri uri, String errorMessage) {
	final Exception error = Exception(errorMessage);
	return RouteMatchList(
	matches: const <RouteMatch>[],
	error: error,
	uri: uri,
	pathParameters: const <String, String>{},
	);
	}

	/// The list of top level routes used by [GoRouterDelegate].
	final List<RouteBase> routes;

	/// The limit for the number of consecutive redirects.
	final int redirectLimit;

	/// The global key for top level navigator.
	final GlobalKey<NavigatorState> navigatorKey;

	/// Top level page redirect.
	final GoRouterRedirect topRedirect;

	final Map<String, String> _nameToPath = <String, String>{};

	/// Looks up the url location by a [GoRoute]'s name.
	String namedLocation(
	String name, {
	Map<String, String> pathParameters = const <String, String>{},
	Map<String, dynamic> queryParameters = const <String, dynamic>{},
	}) {
	assert(() {
	log.info('getting location for name: '
	'"$name"'
	'${pathParameters.isEmpty ? '' : ', pathParameters: $pathParameters'}'
	'${queryParameters.isEmpty ? '' : ', queryParameters: $queryParameters'}');
	return true;
	}());
	final String keyName = name.toLowerCase();
	assert(_nameToPath.containsKey(keyName), 'unknown route name: $name');
	final String path = _nameToPath[keyName]!;
	assert(() {
	// Check that all required params are present
	final List<String> paramNames = <String>[];
	patternToRegExp(path, paramNames);
	for (final String paramName in paramNames) {
	assert(pathParameters.containsKey(paramName),
	'missing param "$paramName" for $path');
	}

	// Check that there are no extra params
	for (final String key in pathParameters.keys) {
	assert(paramNames.contains(key), 'unknown param "$key" for $path');
	}
	return true;
	}());
	final Map<String, String> encodedParams = <String, String>{
	for (final MapEntry<String, String> param in pathParameters.entries)
	param.key: Uri.encodeComponent(param.value)
	};
	final String location = patternToPath(path, encodedParams);
	return Uri(
	path: location,
	queryParameters: queryParameters.isEmpty ? null : queryParameters)
	.toString();
	}

	/// Finds the routes that matched the given URL.
	RouteMatchList findMatch(String location, {Object? extra}) {
	final Uri uri = Uri.parse(canonicalUri(location));

	final Map<String, String> pathParameters = <String, String>{};
	final List<RouteMatch>? matches = _getLocRouteMatches(uri, pathParameters);

	if (matches == null) {
	return _errorRouteMatchList(uri, 'no routes for location: $uri');
	}
	return RouteMatchList(
	matches: matches,
	uri: uri,
	pathParameters: pathParameters,
	extra: extra);
	}

	List<RouteMatch>? _getLocRouteMatches(
	Uri uri, Map<String, String> pathParameters) {
	final List<RouteMatch>? result = _getLocRouteRecursively(
	location: uri.path,
	remainingLocation: uri.path,
	matchedLocation: '',
	pathParameters: pathParameters,
	routes: routes,
	);
	return result;
	}

	List<RouteMatch>? _getLocRouteRecursively({
	required String location,
	required String remainingLocation,
	required String matchedLocation,
	required Map<String, String> pathParameters,
	required List<RouteBase> routes,
	}) {
	List<RouteMatch>? result;
	late Map<String, String> subPathParameters;
	// find the set of matches at this level of the tree
	for (final RouteBase route in routes) {
	subPathParameters = <String, String>{};

	final RouteMatch? match = RouteMatch.match(
	route: route,
	remainingLocation: remainingLocation,
	matchedLocation: matchedLocation,
	pathParameters: subPathParameters,
	);

	if (match == null) {
	continue;
	}

	if (match.route is GoRoute &&
	match.matchedLocation.toLowerCase() == location.toLowerCase()) {
	// If it is a complete match, then return the matched route
	// NOTE: need a lower case match because matchedLocation is canonicalized to match
	// the path case whereas the location can be of any case and still match
	result = <RouteMatch>[match];
	} else if (route.routes.isEmpty) {
	// If it is partial match but no sub-routes, bail.
	continue;
	} else {
	// Otherwise, recurse
	final String childRestLoc;
	final String newParentSubLoc;
	if (match.route is ShellRouteBase) {
	childRestLoc = remainingLocation;
	newParentSubLoc = matchedLocation;
	} else {
	assert(location.startsWith(match.matchedLocation));
	assert(remainingLocation.isNotEmpty);

	childRestLoc = location.substring(match.matchedLocation.length +
	(match.matchedLocation == '/' ? 0 : 1));
	newParentSubLoc = match.matchedLocation;
	}

	final List<RouteMatch>? subRouteMatch = _getLocRouteRecursively(
	location: location,
	remainingLocation: childRestLoc,
	matchedLocation: newParentSubLoc,
	pathParameters: subPathParameters,
	routes: route.routes,
	);

	// If there's no sub-route matches, there is no match for this location
	if (subRouteMatch == null) {
	continue;
	}
	result = <RouteMatch>[match, ...subRouteMatch];
	}
	// Should only reach here if there is a match.
	break;
	}
	if (result != null) {
	pathParameters.addAll(subPathParameters);
	}
	return result;
	}

	/// Processes redirects by returning a new [RouteMatchList] representing the new
	/// location.
	FutureOr<RouteMatchList> redirect(
	BuildContext context, FutureOr<RouteMatchList> prevMatchListFuture,
	{required List<RouteMatchList> redirectHistory}) {
	FutureOr<RouteMatchList> processRedirect(RouteMatchList prevMatchList) {
	final String prevLocation = prevMatchList.uri.toString();
	FutureOr<RouteMatchList> processTopLevelRedirect(
	String? topRedirectLocation) {
	if (topRedirectLocation != null &&
	topRedirectLocation != prevLocation) {
	final RouteMatchList newMatch = _getNewMatches(
	topRedirectLocation,
	prevMatchList.uri,
	redirectHistory,
	);
	if (newMatch.isError) {
	return newMatch;
	}
	return redirect(
	context,
	newMatch,
	redirectHistory: redirectHistory,
	);
	}

	FutureOr<RouteMatchList> processRouteLevelRedirect(
	String? routeRedirectLocation) {
	if (routeRedirectLocation != null &&
	routeRedirectLocation != prevLocation) {
	final RouteMatchList newMatch = _getNewMatches(
	routeRedirectLocation,
	prevMatchList.uri,
	redirectHistory,
	);

	if (newMatch.isError) {
	return newMatch;
	}
	return redirect(
	context,
	newMatch,
	redirectHistory: redirectHistory,
	);
	}
	return prevMatchList;
	}

	final FutureOr<String?> routeLevelRedirectResult =
	_getRouteLevelRedirect(context, prevMatchList, 0);
	if (routeLevelRedirectResult is String?) {
	return processRouteLevelRedirect(routeLevelRedirectResult);
	}
	return routeLevelRedirectResult
	.then<RouteMatchList>(processRouteLevelRedirect);
	}

	redirectHistory.add(prevMatchList);
	// Check for top-level redirect
	final FutureOr<String?> topRedirectResult = topRedirect(
	context,
	GoRouterState(
	this,
	location: prevLocation,
	name: null,
	// No name available at the top level trim the query params off the
	// sub-location to match route.redirect
	matchedLocation: prevMatchList.uri.path,
	queryParameters: prevMatchList.uri.queryParameters,
	queryParametersAll: prevMatchList.uri.queryParametersAll,
	extra: prevMatchList.extra,
	pageKey: const ValueKey<String>('topLevel'),
	),
	);

	if (topRedirectResult is String?) {
	return processTopLevelRedirect(topRedirectResult);
	}
	return topRedirectResult.then<RouteMatchList>(processTopLevelRedirect);
	}

	if (prevMatchListFuture is RouteMatchList) {
	return processRedirect(prevMatchListFuture);
	}
	return prevMatchListFuture.then<RouteMatchList>(processRedirect);
	}

	FutureOr<String?> _getRouteLevelRedirect(
	BuildContext context,
	RouteMatchList matchList,
	int currentCheckIndex,
	) {
	if (currentCheckIndex >= matchList.matches.length) {
	return null;
	}
	final RouteMatch match = matchList.matches[currentCheckIndex];
	FutureOr<String?> processRouteRedirect(String? newLocation) =>
	newLocation ??
	_getRouteLevelRedirect(context, matchList, currentCheckIndex + 1);
	final RouteBase route = match.route;
	FutureOr<String?> routeRedirectResult;
	if (route is GoRoute && route.redirect != null) {
	routeRedirectResult = route.redirect!(
	context,
	GoRouterState(
	this,
	location: matchList.uri.toString(),
	matchedLocation: match.matchedLocation,
	name: route.name,
	path: route.path,
	fullPath: matchList.fullPath,
	extra: matchList.extra,
	pathParameters: matchList.pathParameters,
	queryParameters: matchList.uri.queryParameters,
	queryParametersAll: matchList.uri.queryParametersAll,
	pageKey: match.pageKey,
	),
	);
	}
	if (routeRedirectResult is String?) {
	return processRouteRedirect(routeRedirectResult);
	}
	return routeRedirectResult.then<String?>(processRouteRedirect);
	}

	RouteMatchList _getNewMatches(
	String newLocation,
	Uri previousLocation,
	List<RouteMatchList> redirectHistory,
	) {
	try {
	final RouteMatchList newMatch = findMatch(newLocation);
	_addRedirect(redirectHistory, newMatch, previousLocation);
	return newMatch;
	} on RedirectionError catch (e) {
	log.info('Redirection error: ${e.message}');
	return _errorRouteMatchList(e.location, e.message);
	}
	}

	/// Adds the redirect to [redirects] if it is valid.
	///
	/// Throws if a loop is detected or the redirection limit is reached.
	void _addRedirect(
	List<RouteMatchList> redirects,
	RouteMatchList newMatch,
	Uri prevLocation,
	) {
	if (redirects.contains(newMatch)) {
	throw RedirectionError('redirect loop detected',
	<RouteMatchList>[...redirects, newMatch], prevLocation);
	}
	if (redirects.length > redirectLimit) {
	throw RedirectionError('too many redirects',
	<RouteMatchList>[...redirects, newMatch], prevLocation);
	}

	redirects.add(newMatch);

	log.info('redirecting to $newMatch');
	}

	/// Get the location for the provided route.
	///
	/// Builds the absolute path for the route, by concatenating the paths of the
	/// route and all its ancestors.
	String? locationForRoute(RouteBase route) =>
	fullPathForRoute(route, '', routes);

	@override
	String toString() {
	return 'RouterConfiguration: $routes';
	}

	/// Returns the full path of [routes].
	///
	/// Each path is indented based depth of the hierarchy, and its `name`
	/// is also appended if not null
	@visibleForTesting
	String debugKnownRoutes() {
	final StringBuffer sb = StringBuffer();
	sb.writeln('Full paths for routes:');
	_debugFullPathsFor(routes, '', 0, sb);

	if (_nameToPath.isNotEmpty) {
	sb.writeln('known full paths for route names:');
	for (final MapEntry<String, String> e in _nameToPath.entries) {
	sb.writeln(' ${e.key} => ${e.value}');
	}
	}

	return sb.toString();
	}

	void _debugFullPathsFor(List<RouteBase> routes, String parentFullpath,
	int depth, StringBuffer sb) {
	for (final RouteBase route in routes) {
	if (route is GoRoute) {
	final String fullPath = concatenatePaths(parentFullpath, route.path);
	sb.writeln(' => ${''.padLeft(depth * 2)}$fullPath');
	_debugFullPathsFor(route.routes, fullPath, depth + 1, sb);
	} else if (route is ShellRoute) {
	_debugFullPathsFor(route.routes, parentFullpath, depth, sb);
	}
	}
	}

	void _cacheNameToPath(String parentFullPath, List<RouteBase> childRoutes) {
	for (final RouteBase route in childRoutes) {
	if (route is GoRoute) {
	final String fullPath = concatenatePaths(parentFullPath, route.path);

	if (route.name != null) {
	final String name = route.name!.toLowerCase();
	assert(
	!_nameToPath.containsKey(name),
	'duplication fullpaths for name '
	'"$name":${_nameToPath[name]}, $fullPath');
	_nameToPath[name] = fullPath;
	}

	if (route.routes.isNotEmpty) {
	_cacheNameToPath(fullPath, route.routes);
	}
	} else if (route is ShellRouteBase) {
	if (route.routes.isNotEmpty) {
	_cacheNameToPath(parentFullPath, route.routes);
	}
	}
	}
	}
	}