packages/go_router/lib/src/go_route_information_parser.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 'package:flutter/foundation.dart';
 import 'package:flutter/widgets.dart';
 import 'package:go_router/src/go_route_information_provider.dart';

 import 'go_route.dart';
 import 'go_route_match.dart';
 import 'go_router_state.dart';
 import 'logging.dart';
 import 'path_parser.dart';
 import 'typedefs.dart';

 class _ParserError extends Error implements UnsupportedError {
   _ParserError(this.message);

   @override
   final String? message;
 }

 /// GoRouter implementation of the RouteInformationParser base class
 class GoRouteInformationParser
     extends RouteInformationParser<List<GoRouteMatch>> {
   /// Creates a [GoRouteInformationParser].
   GoRouteInformationParser({
     required this.routes,
     required this.redirectLimit,
     required this.topRedirect,
     this.debugRequireGoRouteInformationProvider = false,
   }) : assert(() {
           // check top-level route paths are valid
           for (final GoRoute route in routes) {
             assert(route.path.startsWith('/'),
                 'top-level path must start with "/": ${route.path}');
           }
           return true;
         }()) {
     _cacheNameToPath('', routes);
     assert(() {
       _debugLogKnownRoutes();
       return true;
     }());
   }

   /// List of top level routes used by the go router delegate.
   final List<GoRoute> routes;

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

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

   /// A debug property to assert [GoRouteInformationProvider] is in use along
   /// with this parser.
   ///
   /// An assertion error will be thrown if this property set to true and the
   /// [GoRouteInformationProvider] is not in use.
   ///
   /// Defaults to false.
   final bool debugRequireGoRouteInformationProvider;

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

   void _cacheNameToPath(String parentFullPath, List<GoRoute> childRoutes) {
     for (final GoRoute route in childRoutes) {
       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);
       }
     }
   }

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

       // Check that there are no extra params
       for (final String key in params.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 params.entries)
         param.key: Uri.encodeComponent(param.value)
     };
     final String location = patternToPath(path, encodedParams);
     return Uri(path: location, queryParameters: queryParams).toString();
   }

   /// Concatenates two paths.
   ///
   /// e.g: pathA = /a, pathB = c/d,  concatenatePaths(pathA, pathB) = /a/c/d.
   static String concatenatePaths(String parentPath, String childPath) {
     // at the root, just return the path
     if (parentPath.isEmpty) {
       assert(childPath.startsWith('/'));
       assert(childPath == '/' || !childPath.endsWith('/'));
       return childPath;
     }

     // not at the root, so append the parent path
     assert(childPath.isNotEmpty);
     assert(!childPath.startsWith('/'));
     assert(!childPath.endsWith('/'));
     return '${parentPath == '/' ? '' : parentPath}/$childPath';
   }

   /// for use by the Router architecture as part of the RouteInformationParser
   @override
   Future<List<GoRouteMatch>> parseRouteInformation(
     RouteInformation routeInformation,
   ) {
     assert(() {
       if (debugRequireGoRouteInformationProvider) {
         assert(
             routeInformation is DebugGoRouteInformation,
             'This GoRouteInformationParser needs to be used with '
             'GoRouteInformationProvider, did you forget to pass in '
             'GoRouter.routeInformationProvider to the Router constructor?');
       }
       return true;
     }());
     final List<GoRouteMatch> matches =
         _getLocRouteMatchesWithRedirects(routeInformation);
     // Use [SynchronousFuture] so that the initial url is processed
     // synchronously and remove unwanted initial animations on deep-linking
     return SynchronousFuture<List<GoRouteMatch>>(matches);
   }

   List<GoRouteMatch> _getLocRouteMatchesWithRedirects(
       RouteInformation routeInformation) {
     // start redirecting from the initial location
     List<GoRouteMatch> matches;
     final String location = routeInformation.location!;
     try {
       // watch redirects for loops
       final List<String> redirects = <String>[_canonicalUri(location)];
       bool redirected(String? redir) {
         if (redir == null) {
           return false;
         }

         assert(() {
           if (Uri.tryParse(redir) == null) {
             throw _ParserError('invalid redirect: $redir');
           }
           if (redirects.contains(redir)) {
             throw _ParserError('redirect loop detected: ${<String>[
               ...redirects,
               redir
             ].join(' => ')}');
           }
           if (redirects.length > redirectLimit) {
             throw _ParserError('too many redirects: ${<String>[
               ...redirects,
               redir
             ].join(' => ')}');
           }
           return true;
         }());

         redirects.add(redir);
         assert(() {
           log.info('redirecting to $redir');
           return true;
         }());
         return true;
       }

       // keep looping till we're done redirecting
       while (true) {
         final String loc = redirects.last;

         // check for top-level redirect
         final Uri uri = Uri.parse(loc);
         if (redirected(
           topRedirect(
             GoRouterState(
               this,
               location: loc,
               name: null, // no name available at the top level
               // trim the query params off the subloc to match route.redirect
               subloc: uri.path,
               // pass along the query params 'cuz that's all we have right now
               queryParams: uri.queryParameters,
               extra: routeInformation.state,
             ),
           ),
         )) {
           continue;
         }

         // get stack of route matches
         matches = _getLocRouteMatches(loc, routeInformation.state);

         // merge new params to keep params from previously matched paths, e.g.
         // /family/:fid/person/:pid provides fid and pid to person/:pid
         Map<String, String> previouslyMatchedParams = <String, String>{};
         for (final GoRouteMatch match in matches) {
           assert(
             !previouslyMatchedParams.keys.any(match.encodedParams.containsKey),
             'Duplicated parameter names',
           );
           match.encodedParams.addAll(previouslyMatchedParams);
           previouslyMatchedParams = match.encodedParams;
         }

         // check top route for redirect
         final GoRouteMatch top = matches.last;
         if (redirected(
           top.route.redirect(
             GoRouterState(
               this,
               location: loc,
               subloc: top.subloc,
               name: top.route.name,
               path: top.route.path,
               fullpath: top.fullpath,
               params: top.decodedParams,
               queryParams: top.queryParams,
             ),
           ),
         )) {
           continue;
         }

         // no more redirects!
         break;
       }

       // note that we need to catch it this way to get all the info, e.g. the
       // file/line info for an error in an inline function impl, e.g. an inline
       // `redirect` impl
       // ignore: avoid_catches_without_on_clauses
     } on _ParserError catch (err) {
       // create a match that routes to the error page
       final Exception error = Exception(err.message);
       final Uri uri = Uri.parse(location);
       matches = <GoRouteMatch>[
         GoRouteMatch(
           subloc: uri.path,
           fullpath: uri.path,
           encodedParams: <String, String>{},
           queryParams: uri.queryParameters,
           extra: null,
           error: error,
           route: GoRoute(
               path: location,
               pageBuilder: (BuildContext context, GoRouterState state) {
                 throw UnimplementedError();
               }),
         ),
       ];
     }
     assert(matches.isNotEmpty);
     return matches;
   }

   List<GoRouteMatch> _getLocRouteMatches(String location, Object? extra) {
     final Uri uri = Uri.parse(location);
     final List<GoRouteMatch> result = _getLocRouteRecursively(
       loc: uri.path,
       restLoc: uri.path,
       routes: routes,
       parentFullpath: '',
       parentSubloc: '',
       queryParams: uri.queryParameters,
       extra: extra,
     );

     if (result.isEmpty) {
       throw _ParserError('no routes for location: $location');
     }

     return result;
   }

   static List<GoRouteMatch> _getLocRouteRecursively({
     required String loc,
     required String restLoc,
     required String parentSubloc,
     required List<GoRoute> routes,
     required String parentFullpath,
     required Map<String, String> queryParams,
     required Object? extra,
   }) {
     bool debugGatherAllMatches = false;
     assert(() {
       debugGatherAllMatches = true;
       return true;
     }());
     final List<List<GoRouteMatch>> result = <List<GoRouteMatch>>[];
     // find the set of matches at this level of the tree
     for (final GoRoute route in routes) {
       final String fullpath = concatenatePaths(parentFullpath, route.path);
       final GoRouteMatch? match = GoRouteMatch.match(
         route: route,
         restLoc: restLoc,
         parentSubloc: parentSubloc,
         fullpath: fullpath,
         queryParams: queryParams,
         extra: extra,
       );

       if (match == null) {
         continue;
       }
       if (match.subloc.toLowerCase() == loc.toLowerCase()) {
         // If it is a complete match, then return the matched route
         // NOTE: need a lower case match because subloc is canonicalized to match
         // the path case whereas the location can be of any case and still match
         result.add(<GoRouteMatch>[match]);
       } else if (route.routes.isEmpty) {
         // If it is partial match but no sub-routes, bail.
         continue;
       } else {
         // otherwise recurse
         final String childRestLoc =
             loc.substring(match.subloc.length + (match.subloc == '/' ? 0 : 1));
         assert(loc.startsWith(match.subloc));
         assert(restLoc.isNotEmpty);

         final List<GoRouteMatch> subRouteMatch = _getLocRouteRecursively(
           loc: loc,
           restLoc: childRestLoc,
           parentSubloc: match.subloc,
           routes: route.routes,
           parentFullpath: fullpath,
           queryParams: queryParams,
           extra: extra,
         ).toList();

         // if there's no sub-route matches, there is no match for this
         // location
         if (subRouteMatch.isEmpty) {
           continue;
         }
         result.add(<GoRouteMatch>[match, ...subRouteMatch]);
       }
       // Should only reach here if there is a match.
       if (debugGatherAllMatches) {
         continue;
       } else {
         break;
       }
     }

     if (result.isEmpty) {
       return <GoRouteMatch>[];
     }

     // If there are multiple routes that match the location, returning the first one.
     // To make predefined routes to take precedence over dynamic routes eg. '/:id'
     // consider adding the dynamic route at the end of the routes
     return result.first;
   }

   void _debugLogKnownRoutes() {
     log.info('known full paths for routes:');
     _debugLogFullPathsFor(routes, '', 0);

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

   void _debugLogFullPathsFor(
     List<GoRoute> routes,
     String parentFullpath,
     int depth,
   ) {
     for (final GoRoute route in routes) {
       final String fullpath = concatenatePaths(parentFullpath, route.path);
       assert(() {
         log.info('  => ${''.padLeft(depth * 2)}$fullpath');
         return true;
       }());
       _debugLogFullPathsFor(route.routes, fullpath, depth + 1);
     }
   }

   /// for use by the Router architecture as part of the RouteInformationParser
   @override
   RouteInformation restoreRouteInformation(List<GoRouteMatch> configuration) {
     return RouteInformation(
         location: configuration.last.fullUriString,
         state: configuration.last.extra);
   }
 }

 /// Normalizes the location string.
 String _canonicalUri(String loc) {
   String canon = Uri.parse(loc).toString();
   canon = canon.endsWith('?') ? canon.substring(0, canon.length - 1) : canon;

   // remove trailing slash except for when you shouldn't, e.g.
   // /profile/ => /profile
   // / => /
   // /login?from=/ => login?from=/
   canon = canon.endsWith('/') && canon != '/' && !canon.contains('?')
       ? canon.substring(0, canon.length - 1)
       : canon;

   // /login/?from=/ => /login?from=/
   // /?from=/ => /?from=/
   canon = canon.replaceFirst('/?', '?', 1);

   return canon;
 }
	// 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 'package:flutter/foundation.dart';
	import 'package:flutter/widgets.dart';
	import 'package:go_router/src/go_route_information_provider.dart';

	import 'go_route.dart';
	import 'go_route_match.dart';
	import 'go_router_state.dart';
	import 'logging.dart';
	import 'path_parser.dart';
	import 'typedefs.dart';

	class _ParserError extends Error implements UnsupportedError {
	_ParserError(this.message);

	@override
	final String? message;
	}

	/// GoRouter implementation of the RouteInformationParser base class
	class GoRouteInformationParser
	extends RouteInformationParser<List<GoRouteMatch>> {
	/// Creates a [GoRouteInformationParser].
	GoRouteInformationParser({
	required this.routes,
	required this.redirectLimit,
	required this.topRedirect,
	this.debugRequireGoRouteInformationProvider = false,
	}) : assert(() {
	// check top-level route paths are valid
	for (final GoRoute route in routes) {
	assert(route.path.startsWith('/'),
	'top-level path must start with "/": ${route.path}');
	}
	return true;
	}()) {
	_cacheNameToPath('', routes);
	assert(() {
	_debugLogKnownRoutes();
	return true;
	}());
	}

	/// List of top level routes used by the go router delegate.
	final List<GoRoute> routes;

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

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

	/// A debug property to assert [GoRouteInformationProvider] is in use along
	/// with this parser.
	///
	/// An assertion error will be thrown if this property set to true and the
	/// [GoRouteInformationProvider] is not in use.
	///
	/// Defaults to false.
	final bool debugRequireGoRouteInformationProvider;

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

	void _cacheNameToPath(String parentFullPath, List<GoRoute> childRoutes) {
	for (final GoRoute route in childRoutes) {
	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);
	}
	}
	}

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

	// Check that there are no extra params
	for (final String key in params.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 params.entries)
	param.key: Uri.encodeComponent(param.value)
	};
	final String location = patternToPath(path, encodedParams);
	return Uri(path: location, queryParameters: queryParams).toString();
	}

	/// Concatenates two paths.
	///
	/// e.g: pathA = /a, pathB = c/d, concatenatePaths(pathA, pathB) = /a/c/d.
	static String concatenatePaths(String parentPath, String childPath) {
	// at the root, just return the path
	if (parentPath.isEmpty) {
	assert(childPath.startsWith('/'));
	assert(childPath == '/' \|\| !childPath.endsWith('/'));
	return childPath;
	}

	// not at the root, so append the parent path
	assert(childPath.isNotEmpty);
	assert(!childPath.startsWith('/'));
	assert(!childPath.endsWith('/'));
	return '${parentPath == '/' ? '' : parentPath}/$childPath';
	}

	/// for use by the Router architecture as part of the RouteInformationParser
	@override
	Future<List<GoRouteMatch>> parseRouteInformation(
	RouteInformation routeInformation,
	) {
	assert(() {
	if (debugRequireGoRouteInformationProvider) {
	assert(
	routeInformation is DebugGoRouteInformation,
	'This GoRouteInformationParser needs to be used with '
	'GoRouteInformationProvider, did you forget to pass in '
	'GoRouter.routeInformationProvider to the Router constructor?');
	}
	return true;
	}());
	final List<GoRouteMatch> matches =
	_getLocRouteMatchesWithRedirects(routeInformation);
	// Use [SynchronousFuture] so that the initial url is processed
	// synchronously and remove unwanted initial animations on deep-linking
	return SynchronousFuture<List<GoRouteMatch>>(matches);
	}

	List<GoRouteMatch> _getLocRouteMatchesWithRedirects(
	RouteInformation routeInformation) {
	// start redirecting from the initial location
	List<GoRouteMatch> matches;
	final String location = routeInformation.location!;
	try {
	// watch redirects for loops
	final List<String> redirects = <String>[_canonicalUri(location)];
	bool redirected(String? redir) {
	if (redir == null) {
	return false;
	}

	assert(() {
	if (Uri.tryParse(redir) == null) {
	throw _ParserError('invalid redirect: $redir');
	}
	if (redirects.contains(redir)) {
	throw _ParserError('redirect loop detected: ${<String>[
	...redirects,
	redir
	].join(' => ')}');
	}
	if (redirects.length > redirectLimit) {
	throw _ParserError('too many redirects: ${<String>[
	...redirects,
	redir
	].join(' => ')}');
	}
	return true;
	}());

	redirects.add(redir);
	assert(() {
	log.info('redirecting to $redir');
	return true;
	}());
	return true;
	}

	// keep looping till we're done redirecting
	while (true) {
	final String loc = redirects.last;

	// check for top-level redirect
	final Uri uri = Uri.parse(loc);
	if (redirected(
	topRedirect(
	GoRouterState(
	this,
	location: loc,
	name: null, // no name available at the top level
	// trim the query params off the subloc to match route.redirect
	subloc: uri.path,
	// pass along the query params 'cuz that's all we have right now
	queryParams: uri.queryParameters,
	extra: routeInformation.state,
	),
	),
	)) {
	continue;
	}

	// get stack of route matches
	matches = _getLocRouteMatches(loc, routeInformation.state);

	// merge new params to keep params from previously matched paths, e.g.
	// /family/:fid/person/:pid provides fid and pid to person/:pid
	Map<String, String> previouslyMatchedParams = <String, String>{};
	for (final GoRouteMatch match in matches) {
	assert(
	!previouslyMatchedParams.keys.any(match.encodedParams.containsKey),
	'Duplicated parameter names',
	);
	match.encodedParams.addAll(previouslyMatchedParams);
	previouslyMatchedParams = match.encodedParams;
	}

	// check top route for redirect
	final GoRouteMatch top = matches.last;
	if (redirected(
	top.route.redirect(
	GoRouterState(
	this,
	location: loc,
	subloc: top.subloc,
	name: top.route.name,
	path: top.route.path,
	fullpath: top.fullpath,
	params: top.decodedParams,
	queryParams: top.queryParams,
	),
	),
	)) {
	continue;
	}

	// no more redirects!
	break;
	}

	// note that we need to catch it this way to get all the info, e.g. the
	// file/line info for an error in an inline function impl, e.g. an inline
	// `redirect` impl
	// ignore: avoid_catches_without_on_clauses
	} on _ParserError catch (err) {
	// create a match that routes to the error page
	final Exception error = Exception(err.message);
	final Uri uri = Uri.parse(location);
	matches = <GoRouteMatch>[
	GoRouteMatch(
	subloc: uri.path,
	fullpath: uri.path,
	encodedParams: <String, String>{},
	queryParams: uri.queryParameters,
	extra: null,
	error: error,
	route: GoRoute(
	path: location,
	pageBuilder: (BuildContext context, GoRouterState state) {
	throw UnimplementedError();
	}),
	),
	];
	}
	assert(matches.isNotEmpty);
	return matches;
	}

	List<GoRouteMatch> _getLocRouteMatches(String location, Object? extra) {
	final Uri uri = Uri.parse(location);
	final List<GoRouteMatch> result = _getLocRouteRecursively(
	loc: uri.path,
	restLoc: uri.path,
	routes: routes,
	parentFullpath: '',
	parentSubloc: '',
	queryParams: uri.queryParameters,
	extra: extra,
	);

	if (result.isEmpty) {
	throw _ParserError('no routes for location: $location');
	}

	return result;
	}

	static List<GoRouteMatch> _getLocRouteRecursively({
	required String loc,
	required String restLoc,
	required String parentSubloc,
	required List<GoRoute> routes,
	required String parentFullpath,
	required Map<String, String> queryParams,
	required Object? extra,
	}) {
	bool debugGatherAllMatches = false;
	assert(() {
	debugGatherAllMatches = true;
	return true;
	}());
	final List<List<GoRouteMatch>> result = <List<GoRouteMatch>>[];
	// find the set of matches at this level of the tree
	for (final GoRoute route in routes) {
	final String fullpath = concatenatePaths(parentFullpath, route.path);
	final GoRouteMatch? match = GoRouteMatch.match(
	route: route,
	restLoc: restLoc,
	parentSubloc: parentSubloc,
	fullpath: fullpath,
	queryParams: queryParams,
	extra: extra,
	);

	if (match == null) {
	continue;
	}
	if (match.subloc.toLowerCase() == loc.toLowerCase()) {
	// If it is a complete match, then return the matched route
	// NOTE: need a lower case match because subloc is canonicalized to match
	// the path case whereas the location can be of any case and still match
	result.add(<GoRouteMatch>[match]);
	} else if (route.routes.isEmpty) {
	// If it is partial match but no sub-routes, bail.
	continue;
	} else {
	// otherwise recurse
	final String childRestLoc =
	loc.substring(match.subloc.length + (match.subloc == '/' ? 0 : 1));
	assert(loc.startsWith(match.subloc));
	assert(restLoc.isNotEmpty);

	final List<GoRouteMatch> subRouteMatch = _getLocRouteRecursively(
	loc: loc,
	restLoc: childRestLoc,
	parentSubloc: match.subloc,
	routes: route.routes,
	parentFullpath: fullpath,
	queryParams: queryParams,
	extra: extra,
	).toList();

	// if there's no sub-route matches, there is no match for this
	// location
	if (subRouteMatch.isEmpty) {
	continue;
	}
	result.add(<GoRouteMatch>[match, ...subRouteMatch]);
	}
	// Should only reach here if there is a match.
	if (debugGatherAllMatches) {
	continue;
	} else {
	break;
	}
	}

	if (result.isEmpty) {
	return <GoRouteMatch>[];
	}

	// If there are multiple routes that match the location, returning the first one.
	// To make predefined routes to take precedence over dynamic routes eg. '/:id'
	// consider adding the dynamic route at the end of the routes
	return result.first;
	}

	void _debugLogKnownRoutes() {
	log.info('known full paths for routes:');
	_debugLogFullPathsFor(routes, '', 0);

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

	void _debugLogFullPathsFor(
	List<GoRoute> routes,
	String parentFullpath,
	int depth,
	) {
	for (final GoRoute route in routes) {
	final String fullpath = concatenatePaths(parentFullpath, route.path);
	assert(() {
	log.info(' => ${''.padLeft(depth * 2)}$fullpath');
	return true;
	}());
	_debugLogFullPathsFor(route.routes, fullpath, depth + 1);
	}
	}

	/// for use by the Router architecture as part of the RouteInformationParser
	@override
	RouteInformation restoreRouteInformation(List<GoRouteMatch> configuration) {
	return RouteInformation(
	location: configuration.last.fullUriString,
	state: configuration.last.extra);
	}
	}

	/// Normalizes the location string.
	String _canonicalUri(String loc) {
	String canon = Uri.parse(loc).toString();
	canon = canon.endsWith('?') ? canon.substring(0, canon.length - 1) : canon;

	// remove trailing slash except for when you shouldn't, e.g.
	// /profile/ => /profile
	// / => /
	// /login?from=/ => login?from=/
	canon = canon.endsWith('/') && canon != '/' && !canon.contains('?')
	? canon.substring(0, canon.length - 1)
	: canon;

	// /login/?from=/ => /login?from=/
	// /?from=/ => /?from=/
	canon = canon.replaceFirst('/?', '?', 1);

	return canon;
	}