Revert "[web] Support custom url strategies"

ci/licenses_golden/licenses_flutter

@@ -426,6 +426,7 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/alarm_clock.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/assets.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/bitmap_canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/browser_detection.dart
+FILE: ../../../flutter/lib/web_ui/lib/src/engine/browser_location.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/canvas_pool.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/canvaskit/canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/canvaskit/canvaskit_api.dart
@@ -462,9 +463,7 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/dom_canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/dom_renderer.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/engine_canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/frame_reference.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/engine/history/history.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/engine/history/js_url_strategy.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/engine/history/url_strategy.dart
+FILE: ../../../flutter/lib/web_ui/lib/src/engine/history.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/html/backdrop_filter.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/html/canvas.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/html/clip.dart

lib/web_ui/lib/src/engine.dart

@@ -26,6 +26,7 @@ part 'engine/alarm_clock.dart';
 part 'engine/assets.dart';
 part 'engine/bitmap_canvas.dart';
 part 'engine/browser_detection.dart';
+part 'engine/browser_location.dart';
 part 'engine/canvaskit/canvas.dart';
 part 'engine/canvaskit/canvaskit_canvas.dart';
 part 'engine/canvaskit/canvaskit_api.dart';
@@ -62,9 +63,7 @@ part 'engine/dom_canvas.dart';
 part 'engine/dom_renderer.dart';
 part 'engine/engine_canvas.dart';
 part 'engine/frame_reference.dart';
-part 'engine/navigation/history.dart';
-part 'engine/navigation/js_url_strategy.dart';
-part 'engine/navigation/url_strategy.dart';
+part 'engine/history.dart';
 part 'engine/html/backdrop_filter.dart';
 part 'engine/html/canvas.dart';
 part 'engine/html/clip.dart';

lib/web_ui/lib/src/engine/browser_location.dart

@@ -0,0 +1,211 @@
+// 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.
+
+// @dart = 2.10
+part of engine;
+
+// TODO(mdebbar): add other strategies.
+
+// Some parts of this file were inspired/copied from the AngularDart router.
+
+/// [LocationStrategy] is responsible for representing and reading route state
+/// from the browser's URL.
+///
+/// At the moment, only one strategy is implemented: [HashLocationStrategy].
+///
+/// This is used by [BrowserHistory] to interact with browser history APIs.
+abstract class LocationStrategy {
+  const LocationStrategy();
+
+  /// Subscribes to popstate events and returns a function that could be used to
+  /// unsubscribe from popstate events.
+  ui.VoidCallback onPopState(html.EventListener fn);
+
+  /// The active path in the browser history.
+  String get path;
+
+  /// The state of the current browser history entry.
+  dynamic get state;
+
+  /// Given a path that's internal to the app, create the external url that
+  /// will be used in the browser.
+  String prepareExternalUrl(String internalUrl);
+
+  /// Push a new history entry.
+  void pushState(dynamic state, String title, String url);
+
+  /// Replace the currently active history entry.
+  void replaceState(dynamic state, String title, String url);
+
+  /// Go to the previous history entry.
+  Future<void> back({int count = 1});
+}
+
+/// This is an implementation of [LocationStrategy] that uses the browser URL's
+/// [hash fragments](https://en.wikipedia.org/wiki/Uniform_Resource_Locator#Syntax)
+/// to represent its state.
+///
+/// In order to use this [LocationStrategy] for an app, it needs to be set in
+/// [ui.window.locationStrategy]:
+///
+/// ```dart
+/// import 'package:flutter_web/material.dart';
+/// import 'package:flutter_web/ui.dart' as ui;
+///
+/// void main() {
+///   ui.window.locationStrategy = const ui.HashLocationStrategy();
+///   runApp(MyApp());
+/// }
+/// ```
+class HashLocationStrategy extends LocationStrategy {
+  final PlatformLocation _platformLocation;
+
+  const HashLocationStrategy(
+      [this._platformLocation = const BrowserPlatformLocation()]);
+
+  @override
+  ui.VoidCallback onPopState(html.EventListener fn) {
+    _platformLocation.onPopState(fn);
+    return () => _platformLocation.offPopState(fn);
+  }
+
+  @override
+  String get path {
+    // the hash value is always prefixed with a `#`
+    // and if it is empty then it will stay empty
+    String path = _platformLocation.hash ?? '';
+    assert(path.isEmpty || path.startsWith('#'));
+
+    // We don't want to return an empty string as a path. Instead we default to "/".
+    if (path.isEmpty || path == '#') {
+      return '/';
+    }
+    // At this point, we know [path] starts with "#" and isn't empty.
+    return path.substring(1);
+  }
+
+  @override
+  dynamic get state => _platformLocation.state;
+
+  @override
+  String prepareExternalUrl(String internalUrl) {
+    // It's convention that if the hash path is empty, we omit the `#`; however,
+    // if the empty URL is pushed it won't replace any existing fragment. So
+    // when the hash path is empty, we instead return the location's path and
+    // query.
+    return internalUrl.isEmpty
+        ? '${_platformLocation.pathname}${_platformLocation.search}'
+        : '#$internalUrl';
+  }
+
+  @override
+  void pushState(dynamic state, String title, String url) {
+    _platformLocation.pushState(state, title, prepareExternalUrl(url));
+  }
+
+  @override
+  void replaceState(dynamic state, String title, String url) {
+    _platformLocation.replaceState(state, title, prepareExternalUrl(url));
+  }
+
+  @override
+  Future<void> back({int count = 1}) {
+    _platformLocation.back(count);
+    return _waitForPopState();
+  }
+
+  /// Waits until the next popstate event is fired.
+  ///
+  /// This is useful for example to wait until the browser has handled the
+  /// `history.back` transition.
+  Future<void> _waitForPopState() {
+    final Completer<void> completer = Completer<void>();
+    late ui.VoidCallback unsubscribe;
+    unsubscribe = onPopState((_) {
+      unsubscribe();
+      completer.complete();
+    });
+    return completer.future;
+  }
+}
+
+/// [PlatformLocation] encapsulates all calls to DOM apis, which allows the
+/// [LocationStrategy] classes to be platform agnostic and testable.
+///
+/// The [PlatformLocation] class is used directly by all implementations of
+/// [LocationStrategy] when they need to interact with the DOM apis like
+/// pushState, popState, etc...
+abstract class PlatformLocation {
+  const PlatformLocation();
+
+  void onPopState(html.EventListener fn);
+  void offPopState(html.EventListener fn);
+
+  void onHashChange(html.EventListener fn);
+  void offHashChange(html.EventListener fn);
+
+  String get pathname;
+  String get search;
+  String? get hash;
+  dynamic get state;
+
+  void pushState(dynamic state, String title, String url);
+  void replaceState(dynamic state, String title, String url);
+  void back(int count);
+}
+
+/// An implementation of [PlatformLocation] for the browser.
+class BrowserPlatformLocation extends PlatformLocation {
+  html.Location get _location => html.window.location;
+  html.History get _history => html.window.history;
+
+  const BrowserPlatformLocation();
+
+  @override
+  void onPopState(html.EventListener fn) {
+    html.window.addEventListener('popstate', fn);
+  }
+
+  @override
+  void offPopState(html.EventListener fn) {
+    html.window.removeEventListener('popstate', fn);
+  }
+
+  @override
+  void onHashChange(html.EventListener fn) {
+    html.window.addEventListener('hashchange', fn);
+  }
+
+  @override
+  void offHashChange(html.EventListener fn) {
+    html.window.removeEventListener('hashchange', fn);
+  }
+
+  @override
+  String get pathname => _location.pathname!;
+
+  @override
+  String get search => _location.search!;
+
+  @override
+  String get hash => _location.hash;
+
+  @override
+  dynamic get state => _history.state;
+
+  @override
+  void pushState(dynamic state, String title, String url) {
+    _history.pushState(state, title, url);
+  }
+
+  @override
+  void replaceState(dynamic state, String title, String url) {
+    _history.replaceState(state, title, url);
+  }
+
+  @override
+  void back(int count) {
+    _history.go(-count);
+  }
+}