Index: pkg/string_scanner/lib/src/span_scanner.dart |
diff --git a/pkg/string_scanner/lib/src/span_scanner.dart b/pkg/string_scanner/lib/src/span_scanner.dart |
new file mode 100644 |
index 0000000000000000000000000000000000000000..9060e62f0d3d28a3f416f16912e0af4881ba58b4 |
--- /dev/null |
+++ b/pkg/string_scanner/lib/src/span_scanner.dart |
@@ -0,0 +1,95 @@ |
+// 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_maps/source_maps.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(line, 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 [Span] 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. |
+ Span get lastSpan => _lastSpan; |
+ Span _lastSpan; |
+ |
+ /// Returns an empty span at the current location. |
+ Span get emptySpan => _sourceFile.span(position); |
+ |
+ /// Creates a new [SpanScanner] that starts scanning from [position]. |
+ /// |
+ /// [sourceUrl] is used as [Location.sourceUrl] for the returned [Span]s as |
+ /// well as for error reporting. |
+ SpanScanner(String string, sourceUrl, {int position}) |
+ : _sourceFile = new SourceFile.text( |
+ sourceUrl is Uri ? sourceUrl.toString() : sourceUrl, string), |
+ super(string, sourceUrl: sourceUrl, position: position); |
+ |
+ /// Creates a [Span] representing the source range between [startState] and |
+ /// the current position. |
+ Span spanFrom(LineScannerState startState) => |
+ _sourceFile.span(startState.position, position); |
+ |
+ 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, string, sourceUrl, span); |
+ } |
+} |
+ |
+/// 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(line, position); |
+ |
+ _SpanScannerState(this._scanner, this.position); |
+} |