chore: Copy path_utils.dart from go_router

packages/go_router_builder/lib/src/path_utils.dart

@@ -0,0 +1,160 @@
+// 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 'route.dart';
+
+final RegExp _parameterRegExp = RegExp(r':(\w+)(\((?:\\.|[^\\()])+\))?');
+
+/// Converts a [pattern] such as `/user/:id` into [RegExp].
+///
+/// The path parameters can be specified by prefixing them with `:`. The
+/// `parameters` are used for storing path parameter names.
+///
+///
+/// For example:
+///
+///  `pattern` = `/user/:id/book/:bookId`
+///
+///  The `parameters` would contain `['id', 'bookId']` as a result of calling
+///  this method.
+///
+/// To extract the path parameter values from a [RegExpMatch], pass the
+/// [RegExpMatch] into [extractPathParameters] with the `parameters` that are
+/// used for generating the [RegExp].
+RegExp patternToRegExp(String pattern, List<String> parameters) {
+  final StringBuffer buffer = StringBuffer('^');
+  int start = 0;
+  for (final RegExpMatch match in _parameterRegExp.allMatches(pattern)) {
+    if (match.start > start) {
+      buffer.write(RegExp.escape(pattern.substring(start, match.start)));
+    }
+    final String name = match[1]!;
+    final String? optionalPattern = match[2];
+    final String regex = optionalPattern != null
+        ? _escapeGroup(optionalPattern, name)
+        : '(?<$name>[^/]+)';
+    buffer.write(regex);
+    parameters.add(name);
+    start = match.end;
+  }
+
+  if (start < pattern.length) {
+    buffer.write(RegExp.escape(pattern.substring(start)));
+  }
+
+  if (!pattern.endsWith('/')) {
+    buffer.write(r'(?=/|$)');
+  }
+  return RegExp(buffer.toString(), caseSensitive: false);
+}
+
+String _escapeGroup(String group, [String? name]) {
+  final String escapedGroup = group.replaceFirstMapped(
+      RegExp(r'[:=!]'), (Match match) => '\\${match[0]}');
+  if (name != null) {
+    return '(?<$name>$escapedGroup)';
+  }
+  return escapedGroup;
+}
+
+/// Reconstructs the full path from a [pattern] and path parameters.
+///
+/// This is useful for restoring the original path from a [RegExpMatch].
+///
+/// For example, A path matched a [RegExp] returned from [patternToRegExp] and
+/// produced a [RegExpMatch]. To reconstruct the path from the match, one
+/// can follow these steps:
+///
+/// 1. Get the `pathParameters` by calling [extractPathParameters] with the
+///    [RegExpMatch] and the parameters used for generating the [RegExp].
+/// 2. Call [patternToPath] with the `pathParameters` from the first step and
+///    the original `pattern` used for generating the [RegExp].
+String patternToPath(String pattern, Map<String, String> pathParameters) {
+  final StringBuffer buffer = StringBuffer();
+  int start = 0;
+  for (final RegExpMatch match in _parameterRegExp.allMatches(pattern)) {
+    if (match.start > start) {
+      buffer.write(pattern.substring(start, match.start));
+    }
+    final String name = match[1]!;
+    buffer.write(pathParameters[name]);
+    start = match.end;
+  }
+
+  if (start < pattern.length) {
+    buffer.write(pattern.substring(start));
+  }
+  return buffer.toString();
+}
+
+/// Extracts arguments from the `match` and maps them by parameter name.
+///
+/// The [parameters] should originate from the call to [patternToRegExp] that
+/// creates the [RegExp].
+Map<String, String> extractPathParameters(
+    List<String> parameters, RegExpMatch match) {
+  return <String, String>{
+    for (int i = 0; i < parameters.length; ++i)
+      parameters[i]: match.namedGroup(parameters[i])!
+  };
+}
+
+/// Concatenates two paths.
+///
+/// e.g: pathA = /a, pathB = c/d,  concatenatePaths(pathA, pathB) = /a/c/d.
+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';
+}
+
+/// 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;
+}
+
+/// Builds an absolute path for the provided route.
+String? fullPathForRoute(
+    RouteBase targetRoute, String parentFullpath, List<RouteBase> routes) {
+  for (final RouteBase route in routes) {
+    final String fullPath = (route is GoRoute)
+        ? concatenatePaths(parentFullpath, route.path)
+        : parentFullpath;
+
+    if (route == targetRoute) {
+      return fullPath;
+    } else {
+      final String? subRoutePath =
+          fullPathForRoute(targetRoute, fullPath, route.routes);
+      if (subRoutePath != null) {
+        return subRoutePath;
+      }
+    }
+  }
+  return null;
+}