add LibraryIdentifier

lib/src/initializer.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.
 part of initialize;
 
 /// Implement this class to create your own initializer.
 ///
 /// Hello world example:
 ///
 ///   class Print implements Initializer<Type> {
 ///     final String message;
 ///     const Print(this.message);
 ///
 ///     @override
 ///     initialize(Type t) => print('$t says `$message`');
 ///   }
 ///
 ///   @Print('hello world!')
 ///   class Foo {}
 ///
 /// Call [run] from your main and this will print 'Foo says `hello world!`'
 ///
 abstract class Initializer<T> {
   dynamic initialize(T target);
 }
 
 /// Typedef for a custom filter function.
 typedef bool InitializerFilter(Initializer initializer);
+
+/// When annotating libraries, this is passed to the initializer.
+class LibraryIdentifier {
+  // The qualified name of the library.
+  final Symbol name;
+
+  // The package this library lives in. May be null if its the same as the root
+  // package.
+  final String package;
+
+  // The path to the library.
+  final String path;
+
+  const LibraryIdentifier(this.name, this.package, this.path);
+
+  bool operator ==(LibraryIdentifier other) =>
+      name == other.name && package == other.package && path == other.path;
+
+  String toString() => '$name: $package:$path';
+}