Add Resource package.

lib/src/loader.dart

+// Copyright (c) 2015, 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 resource.loader;
+
+import "dart:async" show Future, Stream;
+import "dart:convert" show Encoding;
+import "io.dart" as io;  // TODO: make this import configuration dependent.
+
+/// Resource loading strategy.
+///
+/// An abstraction of the functionality needed to load resources.
+///
+/// An implementation decides which URI schemes it supports.
+abstract class ResourceLoader {
+  /// Reads the file located by [uri] as a stream of bytes.

[floitsch, 2015/10/13 12:47:50]

I wouldn't use the term "file".

+  Stream<List<int>> openRead(Uri uri);
+
+  /// Reads the file located by [uri] as a list of bytes.
+  Future<List<int>> readAsBytes(Uri uri);
+
+  /// Reads the file located by [uri] as a [String].
+  ///
+  /// The file bytes are decoded using [encoding].
+  /// If [encoding] is omittted, it defaults to UTF-8.

[floitsch, 2015/10/13 12:47:50]

omitted

+  Future<String> readAsString(Uri uri, { Encoding encoding });
+}
+
+/// Default implementation of [ResourceLoader].
+///
+/// Uses the system's available loading functionality to implement the
+/// loading functions.
+class DefaultLoader implements ResourceLoader {
+  const DefaultLoader();
+
+  Stream<List<int>> openRead(Uri uri) => io.readAsStream(uri);
+
+  Future<List<int>> readAsBytes(Uri uri) => io.readAsBytes(uri);
+
+  Future<String> readAsString(Uri uri, { Encoding encoding }) =>
+      io.readAsString(uri, encoding);
+}