Create and test source mapping for invocations.

pkg/compiler/lib/src/io/code_output.dart

 // Copyright (c) 2012, 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 dart2js.code_output;
 
 import 'dart:async';
 
 import 'source_information.dart';
 
+/// Listener interface for [CodeOutput] activity.
 abstract class CodeOutputListener {
+  /// Called when [text] is added to the output.
   void onText(String text);
+
+  /// Called when the output is closed with a final length of [length].
   void onDone(int length);
 }
 
-abstract class CodeOutput {
+/// Interface for a mapping of target offsets to source locations.
+abstract class SourceLocations {
+  /// Adds a [sourceLocation] at the specified [targetOffset].
+  void addSourceLocation(int targetOffset, SourceLocation sourcePosition);
+
+  /// Applies [f] to every target offset and associated source location.
+  void forEachSourceLocation(void f(int targetOffset,
+                                    SourceLocation sourceLocation));
+}
+
+abstract class CodeOutput implements SourceLocations {
   /// Write [text] to this output.
   ///
   /// If the output is closed, a [StateError] is thrown.
   void add(String text);
 
   /// Adds the content of [buffer] to the output and adds its markers to
   /// [markers].
   ///
   /// If the output is closed, a [StateError] is thrown.
   void addBuffer(CodeBuffer buffer);
 
   /// Returns the number of characters currently write to this output.
   int get length;
 
   /// Returns `true` if this output has been closed.
   bool get isClosed;
 
   /// Closes the output. Further writes will cause a [StateError].
   void close();
-
-  /// Adds a [sourceLocation] at the specified [targetOffset] in the buffer.
-  void addSourceLocation(int targetOffset, SourceLocation sourcePosition);
-
-  /// Applies [f] to every marker in this output.
-  void forEachSourceLocation(void f(int targetOffset,
-                                    SourceLocation sourceLocation));
 }
 
 abstract class AbstractCodeOutput extends CodeOutput {
   Map<int, List<SourceLocation>> markers = <int, List<SourceLocation>>{};
   bool isClosed = false;
 
   void _addInternal(String text);
 
   @override
   void add(String text) {
@@ skipping 81 matching lines @@
   }
 
   void close() {
     output.close();
     super.close();
     if (_listeners != null) {
       _listeners.forEach((listener) => listener.onDone(length));
     }
   }
 }