| Index: mojo/public/dart/third_party/string_scanner/lib/src/span_scanner.dart
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| diff --git a/mojo/public/dart/third_party/string_scanner/lib/src/span_scanner.dart b/mojo/public/dart/third_party/string_scanner/lib/src/span_scanner.dart
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| new file mode 100644
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| index 0000000000000000000000000000000000000000..ebe230d8a70bb93bd2eb16e41da73167555a17c6
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| --- /dev/null
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| +++ b/mojo/public/dart/third_party/string_scanner/lib/src/span_scanner.dart
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| @@ -0,0 +1,115 @@
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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.
|
| +
|
| +library string_scanner.span_scanner;
|
| +
|
| +import 'package:source_span/source_span.dart';
|
| +
|
| +import 'eager_span_scanner.dart';
|
| +import 'exception.dart';
|
| +import 'line_scanner.dart';
|
| +import 'string_scanner.dart';
|
| +import 'utils.dart';
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| +
|
| +/// A subclass of [LineScanner] that exposes matched ranges as source map
|
| +/// [Span]s.
|
| +class SpanScanner extends StringScanner implements LineScanner {
|
| + /// The source of the scanner.
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| + ///
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| + /// This caches line break information and is used to generate [Span]s.
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| + final SourceFile _sourceFile;
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| +
|
| + int get line => _sourceFile.getLine(position);
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| + int get column => _sourceFile.getColumn(position);
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| +
|
| + LineScannerState get state => new _SpanScannerState(this, position);
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| +
|
| + set state(LineScannerState state) {
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| + if (state is! _SpanScannerState ||
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| + !identical((state as _SpanScannerState)._scanner, this)) {
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| + throw new ArgumentError("The given LineScannerState was not returned by "
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| + "this LineScanner.");
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| + }
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| +
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| + this.position = state.position;
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| + }
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| +
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| + /// The [FileSpan] for [lastMatch].
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| + ///
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| + /// This is the span for the entire match. There's no way to get spans for
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| + /// subgroups since [Match] exposes no information about their positions.
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| + FileSpan get lastSpan => _lastSpan;
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| + FileSpan _lastSpan;
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| +
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| + /// The current location of the scanner.
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| + FileLocation get location => _sourceFile.location(position);
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| +
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| + /// Returns an empty span at the current location.
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| + FileSpan get emptySpan => location.pointSpan();
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| +
|
| + /// Creates a new [SpanScanner] that starts scanning from [position].
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| + ///
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| + /// [sourceUrl] is used as [SourceLocation.sourceUrl] for the returned
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| + /// [FileSpan]s as well as for error reporting. It can be a [String], a
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| + /// [Uri], or `null`.
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| + SpanScanner(String string, {sourceUrl, int position})
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| + : _sourceFile = new SourceFile(string, url: sourceUrl),
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| + super(string, sourceUrl: sourceUrl, position: position);
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| +
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| + /// Creates a new [SpanScanner] that eagerly computes line and column numbers.
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| + ///
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| + /// In general [new SpanScanner] will be more efficient, since it avoids extra
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| + /// computation on every scan. However, eager scanning can be useful for
|
| + /// situations where the normal course of parsing frequently involves
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| + /// accessing the current line and column numbers.
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| + ///
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| + /// Note that *only* the `line` and `column` fields on the `SpanScanner`
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| + /// itself and its `LineScannerState` are eagerly computed. To limit their
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| + /// memory footprint, returned spans and locations will still lazily compute
|
| + /// their line and column numbers.
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| + factory SpanScanner.eager(String string, {sourceUrl, int position}) =
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| + EagerSpanScanner;
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| +
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| + /// Creates a [FileSpan] representing the source range between [startState]
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| + /// and the current position.
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| + FileSpan spanFrom(LineScannerState startState, [LineScannerState endState]) {
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| + var endPosition = endState == null ? position : endState.position;
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| + return _sourceFile.span(startState.position, endPosition);
|
| + }
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| +
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| + bool matches(Pattern pattern) {
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| + if (!super.matches(pattern)) {
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| + _lastSpan = null;
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| + return false;
|
| + }
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| +
|
| + _lastSpan = _sourceFile.span(position, lastMatch.end);
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| + return true;
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| + }
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| +
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| + void error(String message, {Match match, int position, int length}) {
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| + validateErrorArgs(string, match, position, length);
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| +
|
| + if (match == null && position == null && length == null) match = lastMatch;
|
| + if (position == null) {
|
| + position = match == null ? this.position : match.start;
|
| + }
|
| + if (length == null) length = match == null ? 1 : match.end - match.start;
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| +
|
| + var span = _sourceFile.span(position, position + length);
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| + throw new StringScannerException(message, span, string);
|
| + }
|
| +}
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| +
|
| +/// A class representing the state of a [SpanScanner].
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| +class _SpanScannerState implements LineScannerState {
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| + /// The [SpanScanner] that created this.
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| + final SpanScanner _scanner;
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| +
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| + final int position;
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| + int get line => _scanner._sourceFile.getLine(position);
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| + int get column => _scanner._sourceFile.getColumn(position);
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| +
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| + _SpanScannerState(this._scanner, this.position);
|
| +}
|
|
|