Factor out the anchor prefix to easily allow switching to #!

client/lib/location.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.
 
 library location;
 
 import 'package:observe/observe.dart';
 
 // These regular expressions are not strictly accurate for picking Dart
 // identifiers out of arbitrary text, e.g. identifiers must start with an
@@ skipping 20 matching lines @@
 /// link which is to a method on the same page as its class. So, e.g.
 /// in `dart-core.Object@id_noSuchMethod,invocation` this separates
 /// the method `noSuchMethod` from the parameter `invocation`.
 const PARAMETER_SEPARATOR = ",";
 
 /// The character used to separate the class name from the constructor
 /// name, e.g. `Future.Future-delayed`. Will occur by itself for
 /// an unnamed constructor. e.g. `Future.Future-`
 const CONSTRUCTOR_SEPARATOR = "-";
 
+/// The prefix to be used for anchors. This is here so that we can easily
+/// factor it out into being #! and use the _escaped_fragment_ scheme
+/// for providing static versions of pages if we get them. See
+/// https://developers.google.com/webmasters/ajax-crawling/
+const AJAX_LOCATION_PREFIX = "#!";
+const BASIC_LOCATION_PREFIX = "#";
+
+// Prefix the string with the separator we are using between the main
+// URL and the location.
+locationPrefixed(String s) => "$BASIC_LOCATION_PREFIX$s";
+
+// Remove the anchor prefix from [s] if it's present.
+locationDeprefixed(String s) {
+  if (s.startsWith(AJAX_LOCATION_PREFIX)) {
+    return s.substring(AJAX_LOCATION_PREFIX.length, s.length);
+  } else if (s.startsWith(BASIC_LOCATION_PREFIX)) {
+    return s.substring(BASIC_LOCATION_PREFIX.length, s.length);
+  } else {
+    return s;
+  }
+}
+
 // This represents a component described by a URI and can give us
 // the URI given the component or vice versa.
 class DocsLocation {
   String packageName;
   String libraryName;
   String memberName;
   String subMemberName;
   String anchor;
 
   // TODO(alanknight): These might be nicer to work with as immutable value
@@ skipping 30 matching lines @@
   }
 
   /// This isn't a particularly good hash code, but we don't really hash
   /// these very much. Just XOR together all the fields.
   int get hashCode => packageName.hashCode ^ libraryName.hashCode ^
       memberName.hashCode ^ subMemberName.hashCode ^ anchor.hashCode;
 
   void _extractPieces(String uri) {
 
     if (uri == null || uri.length == 0) return;
-    var position = (uri[0] == "#") ? 1 : 0;
+    var position = uri.startsWith(AJAX_LOCATION_PREFIX) ?
+        AJAX_LOCATION_PREFIX.length : 0;
 
     _check(regex) {
       var match = regex.matchAsPrefix(uri, position);
       if (match != null) {
         var matchedString = match.group(1);
         position = position + match.group(0).length;
         return matchedString;
       }
     }
 
     packageName = _check(packageMatch);
     libraryName = _check(libraryMatch);
     memberName = _check(memberMatch);
     subMemberName = _check(subMemberMatch);
     anchor = _check(anchorMatch);
     if (position < uri.length && anchor == null) {
       // allow an anchor that's just dotted, not @ if we don't find an @
       // form and we haven't reached the end.
       anchor = uri.substring(position + 1, uri.length);
     }
   }
 
   /// The URI hash string without its leading hash
   /// and without any trailing anchor portion, e.g. for
-  /// http://site/#args/args.ArgParser#id_== it would return args/argsArgParser
+  /// http://site/#args/args.ArgParser@id_== it would return args/argsArgParser
   @reflectable String get withoutAnchor =>
       [packagePlus, libraryPlus, memberPlus, subMemberPlus].join("");
 
   /// The URI hash for just the library portion of this location.
   @reflectable String get libraryQualifiedName => "$packagePlus$libraryPlus";
 
   /// The full URI hash string without the leading hash character.
   /// e.g. for
-  /// http://site/#args/args.ArgParser#id_==
-  /// it would return args/argsArgParser#id_==
+  /// http://site/#args/args.ArgParser@id_==
+  /// it would return args/argsArgParser@id_==
   @reflectable String get withAnchor => withoutAnchor + anchorPlus;
 
   @reflectable DocsLocation get locationWithoutAnchor =>
       new DocsLocation.clone(this)..anchor = null;
 
   /// The package name with the trailing / separator, or the empty
   /// string if the package name is not set.
   @reflectable get packagePlus => packageName == null
       ? ''
       : libraryName == null
@@ skipping 195 matching lines @@
     if (anchor != null) return anchor;
     if (subMemberName != null) return subMemberName;
     if (memberName != null) return memberName;
     if (libraryName != null) return libraryName;
     if (packageName != null) return packageName;
     return null;
   }
 
   @reflectable toString() => 'DocsLocation($withAnchor)';
 }