First pass at asynchronous input loading in dart2js.

sdk/lib/_internal/compiler/implementation/util/link.dart

 // Copyright (c) 2011, 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 org_dartlang_compiler_util;
 
-class Link<T> {
+class Link<T> extends IterableBase<T> implements Iterable<T> {

[Bob Nystrom, 2013/06/26 01:03:24]

I added this because I'm passing a Link<T> to Future.forEach(), which expects an
Iterable. Is this OK?

If not, I can manually copy the Link to a list instead.

[ahe, 2013/06/26 07:02:00]

Nope, we don't support length.
You can say link.toList(), but I've filed http://dartbug.com/11523.

[Bob Nystrom, 2013/06/27 00:38:18]

Ah, that makes sense.
OK, changed it to use that and added TODOs mentioning that bug.

   T get head => null;
   Link<T> get tail => null;
 
   factory Link.fromList(List<T> list) {
     switch (list.length) {
       case 0:
         return new Link<T>();
       case 1:
         return new LinkEntry<T>(list[0]);
       case 2:
@@ skipping 93 matching lines @@
    * Prepends all elements added to the builder to [tail]. The resulting list is
    * returned and the builder is cleared.
    */
   Link<T> toLink([Link<T> tail = const Link()]);
 
   void addLast(T t);
 
   final int length;
   final bool isEmpty;
 }