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