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runtime/observatory/lib/src/app/location_manager.dart

 // Copyright (c) 2013, the Dart 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.
 
 part of app;
 
-abstract class LocationManager extends Observable {
-  final _initialPath = '/vm';
+/// Utility class to decode and encode the fragment (starts with '#') portion
+/// of a url, including any query parameters.
+class FragmentUri {

[turnidge, 2015/04/07 21:24:31]

Do we need to introduce this class?  What if we just stored the fragment as a
Uri?

[Cutch, 2015/04/14 21:45:15]

I've redone this part of the CL.

+  String _path;
+  String get path => _path;
+  final Map<String, String> parameters = new Map<String, String>();
+
+  FragmentUri(String url) {
+    // Chop off leading '#'.
+    if (url.startsWith('#')) {
+      url = url.substring(1);
+    }
+    var queryStringIndex = url.indexOf('?');
+    if (queryStringIndex == -1) {
+      _path = url;
+    } else {
+      _path = url.substring(0, queryStringIndex);
+      parameters.addAll(
+          Uri.splitQueryString(url.substring(queryStringIndex + 1)));
+    }
+  }
+
+  FragmentUri.from(FragmentUri other) {
+    _path = other._path;
+    parameters.addAll(other.parameters);
+  }
+
+  String toString() {
+    if (parameters.isEmpty) {
+      return '#$_path';
+    }
+    var encodedParameters = new Uri(queryParameters: parameters).query;
+    return '#${_path}?${encodedParameters}';
+  }
+}
+
+class LocationManager extends Observable {
+  final _defaultPath = '/vm';
   ObservatoryApplication _app;
-
-  String _lastUrl;
+  FragmentUri _fragment;
+  FragmentUri get fragment => _fragment;
+  String _url;
 
   void _init(ObservatoryApplication app) {
     // Called once.
     assert(_app == null);
     _app = app;
     // Register for history events.
     window.onPopState.listen(_onLocationChange);
-    _onStartup();
+
+    var applicationPath = '${window.location.hash}';
+    if ((window.location.hash == '') || (window.location.hash == '#')) {
+      // Observatory has loaded but no application path has been specified,
+      // use the default.
+      applicationPath = '#${_defaultPath}';
+    }
+    // Update current application path.
+    window.history.replaceState(applicationPath,
+                                document.title,
+                                applicationPath);
+    _updateCurrent(applicationPath);
+    _go(applicationPath);
   }
 
-  void _onStartup();
-  void _onLocationChange(PopStateEvent event);
+  void _updateCurrent(String url) {
+    _url = url;
+    _fragment = new FragmentUri(url);
+  }
 
   void _pushUrl(String url) {
-    if (_lastUrl != url) {
+    if (_url != url) {
       Logger.root.info('Navigated to ${url}');
       window.history.pushState(url, document.title, url);
-      _lastUrl = url;
+      _updateCurrent(url);
     }
   }
 
-  /// Go to a specific url.
-  void go(String url) {
-    if ((url != makeLink('/vm-connect/')) && _app.vm == null) {
-      if (!window.confirm('Connection with VM has been lost. '
-                          'Proceeding will lose current page.')) {
-        return;
-      }
-      url = makeLink('/vm-connect/');
-    }
-    _pushUrl(url);
-    _go(url);
-  }
-
   void _go(String url) {
     // Chop off leading '#'.
     if (url.startsWith('#')) {
       url = url.substring(1);
     }
     // Fall through handles '#/'
     // Chop off leading '/'.
     if (url.startsWith('/')) {
       url = url.substring(1);
     }
     var args;
     // Parse out arguments.
     if (url.contains('---')) {
       var chunks = url.split('---');
       url = chunks[0];
       if ((chunks.length > 1) && (chunks[1] != '')) {
         args = chunks[1];
       }
     }
     _app._visit(url, args);
   }
 
-  /// Go back.
-  void back() {
-    window.history.go(-1);
+  /// Go to a specific url.
+  void go(String url) {
+    if ((url != makeLink('/vm-connect/')) && _app.vm == null) {
+      if (!window.confirm('Connection with VM has been lost. '
+                          'Proceeding will lose current page.')) {
+        return;
+      }
+      url = makeLink('/vm-connect/');
+    }
+    _pushUrl(url);
+    _go(url);
   }
 
-  /// Go forward.
-  void forward() {
-    window.history.go(1);
+  /// Starting with the current url, update all parameters present in
+  /// [updatedParameters], then generate a new url and navigate to that.
+  goParameter(Map updatedParameters) {
+    var fragment = new FragmentUri.from(_fragment);
+    updatedParameters.forEach((k, v) {
+      fragment.parameters[k] = v;
+    });
+    go(fragment.toString());
   }
 
   /// Handle clicking on an application url link.
   void onGoto(MouseEvent event) {
     var target = event.target;
     var href = target.attributes['href'];
     if (event.button > 0 || event.metaKey || event.ctrlKey ||
         event.shiftKey || event.altKey) {
       // Not a left-click or a left-click with a modifier key:
       // Let browser handle.
       return;
     }
     go(href);
     event.preventDefault();
   }
 
-  /// Given an application url, generate a link.
-  String makeLink(String url);
-}
-
-/// Uses location.hash to encode application urls.
-class HashLocationManager extends LocationManager {
-  void _onStartup() {
-    String initialPath = '${window.location.hash}';
-    if ((window.location.hash == '') || (window.location.hash == '#')) {
-      initialPath = '#${_initialPath}';
-    }
-    window.history.pushState(initialPath, document.title, initialPath);
+  /// Called whenever the browser changes the location bar (e.g. back button).
+  void _onLocationChange(PopStateEvent event) {
+    _updateCurrent(window.location.hash);
     _go(window.location.hash);
   }
 
-  void _onLocationChange(PopStateEvent _) {
-    _go(window.location.hash);
-  }
-
-  /// Given an application url, generate a link for an anchor tag.
-  String makeLink(String url) {
-    return '#$url';
-  }
+  /// Given an application url, generate a link.
+  String makeLink(String url) => '#$url';
 }
-
-/// Uses location.pathname to encode application urls. Requires server side
-/// rewriting to support copy and paste linking. pub serve makes this hard.
-/// STATUS: Work in progress.
-class LinkLocationManager extends LocationManager {
-  void _onStartup() {
-    Logger.root.warning('Using untested LinkLocationManager');
-    String initialPath = window.location.pathname;
-    if ((window.location.pathname == '/index.html') ||
-        (window.location.pathname == '/')) {
-      initialPath = '/vm';
-    }
-    window.history.replaceState(initialPath, document.title, initialPath);
-    _go(window.location.pathname);
-  }
-
-  void _onLocationChange(PopStateEvent _) {
-    _go(window.location.pathname);
-  }
-
-  /// Given an application url, generate a link for an anchor tag.
-  String makeLink(String url) => url;
-}