Roll Observatory packages and add a roll script

source_span/lib/src/span_mixin.dart

-// 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.
-
-library source_span.span_mixin;
-
-import 'dart:math' as math;
-import 'package:path/path.dart' as p;
-
-import 'colors.dart' as colors;
-import 'span.dart';
-import 'span_with_context.dart';
-import 'utils.dart';
-
-/// A mixin for easily implementing [SourceSpan].
-///
-/// This implements the [SourceSpan] methods in terms of [start], [end], and
-/// [text]. This assumes that [start] and [end] have the same source URL, that
-/// [start] comes before [end], and that [text] has a number of characters equal
-/// to the distance between [start] and [end].
-abstract class SourceSpanMixin implements SourceSpan {
-  Uri get sourceUrl => start.sourceUrl;
-  int get length => end.offset - start.offset;
-
-  int compareTo(SourceSpan other) {
-    var result = start.compareTo(other.start);
-    return result == 0 ? end.compareTo(other.end) : result;
-  }
-
-  SourceSpan union(SourceSpan other) {
-    if (sourceUrl != other.sourceUrl) {
-      throw new ArgumentError("Source URLs \"${sourceUrl}\" and "
-          " \"${other.sourceUrl}\" don't match.");
-    }
-
-    var start = min(this.start, other.start);
-    var end = max(this.end, other.end);
-    var beginSpan = start == this.start ? this : other;
-    var endSpan = end == this.end ? this : other;
-
-    if (beginSpan.end.compareTo(endSpan.start) < 0) {
-      throw new ArgumentError("Spans $this and $other are disjoint.");
-    }
-
-    var text = beginSpan.text +
-        endSpan.text.substring(beginSpan.end.distance(endSpan.start));
-    return new SourceSpan(start, end, text);
-  }
-
-  String message(String message, {color}) {
-    if (color == true) color = colors.RED;
-    if (color == false) color = null;
-
-    var line = start.line;
-    var column = start.column;
-
-    var buffer = new StringBuffer();
-    buffer.write('line ${line + 1}, column ${column + 1}');
-    if (sourceUrl != null) buffer.write(' of ${p.prettyUri(sourceUrl)}');
-    buffer.write(': $message');
-
-    if (length == 0 && this is! SourceSpanWithContext) return buffer.toString();
-    buffer.write("\n");
-
-    var textLine;
-    if (this is SourceSpanWithContext) {
-      var context = (this as SourceSpanWithContext).context;
-      var lineStart = findLineStart(context, text, column);
-      if (lineStart != null && lineStart > 0) {
-        buffer.write(context.substring(0, lineStart));
-        context = context.substring(lineStart);
-      }
-      var endIndex = context.indexOf('\n');
-      textLine = endIndex == -1 ? context : context.substring(0, endIndex + 1);
-      column = math.min(column, textLine.length - 1);
-    } else {
-      textLine = text.split("\n").first;
-      column = 0;
-    }
-
-    var toColumn =
-        math.min(column + end.offset - start.offset, textLine.length);
-    if (color != null) {
-      buffer.write(textLine.substring(0, column));
-      buffer.write(color);
-      buffer.write(textLine.substring(column, toColumn));
-      buffer.write(colors.NONE);
-      buffer.write(textLine.substring(toColumn));
-    } else {
-      buffer.write(textLine);
-    }
-    if (!textLine.endsWith('\n')) buffer.write('\n');
-    buffer.write(' ' * column);
-    if (color != null) buffer.write(color);
-    buffer.write('^' * math.max(toColumn - column, 1));
-    if (color != null) buffer.write(colors.NONE);
-    return buffer.toString();
-  }
-
-  bool operator ==(other) => other is SourceSpan &&
-      start == other.start && end == other.end;
-
-  int get hashCode => start.hashCode + (31 * end.hashCode);
-
-  String toString() => '<$runtimeType: from $start to $end "$text">';
-}