// 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.diagnostics.source_span;

import '../tokens/token.dart' show
    Token;
import '../tree/tree.dart' show
    Node;
import 'spannable.dart' show
    Spannable;

class SourceSpan implements Spannable {
  final Uri uri;
  final int begin;
  final int end;

  const SourceSpan(this.uri, this.begin, this.end);

  factory SourceSpan.fromNode(Uri uri, Node node) {
    return new SourceSpan.fromTokens(
        uri, node.getBeginToken(), node.getEndToken());
  }

  factory SourceSpan.fromTokens(Uri uri, Token begin, Token end) {
    final beginOffset = begin.charOffset;
    final endOffset = end.charOffset + end.charCount;

    // [begin] and [end] might be the same for the same empty token. This
    // happens for instance when scanning '$$'.
    assert(endOffset >= beginOffset);
    return new SourceSpan(uri, beginOffset, endOffset);
  }

  int get hashCode {
    return 13 * uri.hashCode +
           17 * begin.hashCode +
           19 * end.hashCode;
  }

  bool operator ==(other) {
    if (identical(this, other)) return true;
    if (other is! SourceSpan) return false;
    return uri == other.uri &&
           begin == other.begin &&
           end == other.end;
  }

  String toString() => 'SourceSpan($uri, $begin, $end)';
}