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// Copyright (c) 2014, 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.
import 'location.dart';
import 'span.dart';
import 'utils.dart';
/// A class that describes a segment of source text with additional context.
class SourceSpanWithContext extends SourceSpanBase {
// This is a getter so that subclasses can override it.
/// Text around the span, which includes the line containing this span.
String get context => _context;
final String _context;
/// Creates a new span from [start] to [end] (exclusive) containing [text], in
/// the given [context].
/// [start] and [end] must have the same source URL and [start] must come
/// before [end]. [text] must have a number of characters equal to the
/// distance between [start] and [end]. [context] must contain [text], and
/// [text] should start at `start.column` from the beginning of a line in
/// [context].
SourceLocation start, SourceLocation end, String text, this._context)
: super(start, end, text) {
if (!context.contains(text)) {
throw new ArgumentError(
'The context line "$context" must contain "$text".');
if (findLineStart(context, text, start.column) == null) {
throw new ArgumentError('The span text "$text" must start at '
'column ${start.column + 1} in a line within "$context".');