Index: pkg/compiler/lib/src/io/line_column_provider.dart |
diff --git a/pkg/compiler/lib/src/io/line_column_provider.dart b/pkg/compiler/lib/src/io/line_column_provider.dart |
new file mode 100644 |
index 0000000000000000000000000000000000000000..5aa700cca4a738e5a909b00bf1e7e1c7070a678a |
--- /dev/null |
+++ b/pkg/compiler/lib/src/io/line_column_provider.dart |
@@ -0,0 +1,73 @@ |
+// 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.io.line_column; |
+ |
+import 'code_output.dart'; |
+ |
+/// Interface for providing line/column information. |
+abstract class LineColumnProvider { |
+ /// Returns the line number (0-based) for [offset]. |
+ int getLine(int offset); |
+ |
+ /// Returns the column number (0-based) for [offset] at the given [line]. |
+ int getColumn(int line, int offset); |
+} |
+ |
+/// [CodeOutputListener] that collects line information. |
+class LineColumnCollector extends CodeOutputListener |
+ implements LineColumnProvider { |
+ int lastLineStart = 0; |
+ List<int> lineStarts = <int>[0]; |
+ |
+ void _collect(String text) { |
+ int offset = lastLineStart; |
+ int index = 0; |
+ while (index < text.length) { |
+ // Unix uses '\n' and Windows uses '\r\n', so this algorithm works for |
+ // both platforms. |
+ index = text.indexOf('\n', index) + 1; |
+ if (index <= 0) break; |
+ lastLineStart = offset + index; |
+ lineStarts.add(lastLineStart); |
+ } |
+ } |
+ |
+ @override |
+ void onText(String text) { |
+ _collect(text); |
+ } |
+ |
+ @override |
+ int getLine(int offset) { |
+ List<int> starts = lineStarts; |
+ if (offset < 0 || starts.last <= offset) { |
+ throw 'bad position #$offset in buffer with length ${lineStarts.last}.'; |
+ } |
+ int first = 0; |
+ int count = starts.length; |
+ while (count > 1) { |
+ int step = count ~/ 2; |
+ int middle = first + step; |
+ int lineStart = starts[middle]; |
+ if (offset < lineStart) { |
+ count = step; |
+ } else { |
+ first = middle; |
+ count -= step; |
+ } |
+ } |
+ return first; |
+ } |
+ |
+ @override |
+ int getColumn(int line, int offset) { |
+ return offset - lineStarts[line]; |
+ } |
+ |
+ @override |
+ void onDone(int length) { |
+ lineStarts.add(length); |
+ } |
+} |