| Index: mojo/public/dart/third_party/string_scanner/lib/src/string_scanner.dart
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| diff --git a/mojo/public/dart/third_party/string_scanner/lib/src/string_scanner.dart b/mojo/public/dart/third_party/string_scanner/lib/src/string_scanner.dart
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| new file mode 100644
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| index 0000000000000000000000000000000000000000..d9c1c2fd3c109c692671508a2e514a6bd5e9ec16
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| --- /dev/null
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| +++ b/mojo/public/dart/third_party/string_scanner/lib/src/string_scanner.dart
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| @@ -0,0 +1,176 @@
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| +// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
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| +// for details. All rights reserved. Use of this source code is governed by a
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| +// BSD-style license that can be found in the LICENSE file.
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| +
|
| +library string_scanner.string_scanner;
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| +
|
| +import 'package:source_span/source_span.dart';
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| +
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| +import 'exception.dart';
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| +import 'utils.dart';
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| +
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| +/// When compiled to JS, forward slashes are always escaped in [RegExp.pattern].
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| +///
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| +/// See issue 17998.
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| +final _slashAutoEscape = new RegExp("/").pattern == "\\/";
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| +
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| +/// A class that scans through a string using [Pattern]s.
|
| +class StringScanner {
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| + /// The URL of the source of the string being scanned.
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| + ///
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| + /// This is used for error reporting. It may be `null`, indicating that the
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| + /// source URL is unknown or unavailable.
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| + final Uri sourceUrl;
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| +
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| + /// The string being scanned through.
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| + final String string;
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| +
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| + /// The current position of the scanner in the string, in characters.
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| + int get position => _position;
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| + set position(int position) {
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| + if (position < 0 || position > string.length) {
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| + throw new ArgumentError("Invalid position $position");
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| + }
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| +
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| + _position = position;
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| + }
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| + int _position = 0;
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| +
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| + /// The data about the previous match made by the scanner.
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| + ///
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| + /// If the last match failed, this will be `null`.
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| + Match get lastMatch => _lastMatch;
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| + Match _lastMatch;
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| +
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| + /// The portion of the string that hasn't yet been scanned.
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| + String get rest => string.substring(position);
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| +
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| + /// Whether the scanner has completely consumed [string].
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| + bool get isDone => position == string.length;
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| +
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| + /// Creates a new [StringScanner] that starts scanning from [position].
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| + ///
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| + /// [position] defaults to 0, the beginning of the string. [sourceUrl] is the
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| + /// URL of the source of the string being scanned, if available. It can be
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| + /// a [String], a [Uri], or `null`.
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| + StringScanner(this.string, {sourceUrl, int position})
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| + : sourceUrl = sourceUrl is String ? Uri.parse(sourceUrl) : sourceUrl {
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| + if (position != null) this.position = position;
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| + }
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| +
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| + /// Consumes a single character and returns its character code.
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| + ///
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| + /// This throws a [FormatException] if the string has been fully consumed. It
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| + /// doesn't affect [lastMatch].
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| + int readChar() {
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| + if (isDone) _fail("more input");
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| + return string.codeUnitAt(_position++);
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| + }
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| +
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| + /// Returns the character code of the character [offset] away from [position].
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| + ///
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| + /// [offset] defaults to zero, and may be negative to inspect already-consumed
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| + /// characters.
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| + ///
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| + /// This returns `null` if [offset] points outside the string. It doesn't
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| + /// affect [lastMatch].
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| + int peekChar([int offset]) {
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| + if (offset == null) offset = 0;
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| + var index = position + offset;
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| + if (index < 0 || index >= string.length) return null;
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| + return string.codeUnitAt(index);
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| + }
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| +
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| + /// If [pattern] matches at the current position of the string, scans forward
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| + /// until the end of the match.
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| + ///
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| + /// Returns whether or not [pattern] matched.
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| + bool scan(Pattern pattern) {
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| + var success = matches(pattern);
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| + if (success) _position = _lastMatch.end;
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| + return success;
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| + }
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| +
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| + /// If [pattern] matches at the current position of the string, scans forward
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| + /// until the end of the match.
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| + ///
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| + /// If [pattern] did not match, throws a [FormatException] describing the
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| + /// position of the failure. [name] is used in this error as the expected name
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| + /// of the pattern being matched; if it's `null`, the pattern itself is used
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| + /// instead.
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| + void expect(Pattern pattern, {String name}) {
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| + if (scan(pattern)) return;
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| +
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| + if (name == null) {
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| + if (pattern is RegExp) {
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| + var source = pattern.pattern;
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| + if (!_slashAutoEscape) source = source.replaceAll("/", "\\/");
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| + name = "/$source/";
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| + } else {
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| + name =
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| + pattern.toString().replaceAll("\\", "\\\\").replaceAll('"', '\\"');
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| + name = '"$name"';
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| + }
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| + }
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| + _fail(name);
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| + }
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| +
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| + /// If the string has not been fully consumed, this throws a
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| + /// [FormatException].
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| + void expectDone() {
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| + if (isDone) return;
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| + _fail("no more input");
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| + }
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| +
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| + /// Returns whether or not [pattern] matches at the current position of the
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| + /// string.
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| + ///
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| + /// This doesn't move the scan pointer forward.
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| + bool matches(Pattern pattern) {
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| + _lastMatch = pattern.matchAsPrefix(string, position);
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| + return _lastMatch != null;
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| + }
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| +
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| + /// Returns the substring of [string] between [start] and [end].
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| + ///
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| + /// Unlike [String.substring], [end] defaults to [position] rather than the
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| + /// end of the string.
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| + String substring(int start, [int end]) {
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| + if (end == null) end = position;
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| + return string.substring(start, end);
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| + }
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| +
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| + /// Throws a [FormatException] with [message] as well as a detailed
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| + /// description of the location of the error in the string.
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| + ///
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| + /// [match] is the match information for the span of the string with which the
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| + /// error is associated. This should be a match returned by this scanner's
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| + /// [lastMatch] property. By default, the error is associated with the last
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| + /// match.
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| + ///
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| + /// If [position] and/or [length] are passed, they are used as the error span
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| + /// instead. If only [length] is passed, [position] defaults to the current
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| + /// position; if only [position] is passed, [length] defaults to 1.
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| + ///
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| + /// It's an error to pass [match] at the same time as [position] or [length].
|
| + 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) {
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| + position = match == null ? this.position : match.start;
|
| + }
|
| + if (length == null) length = match == null ? 1 : match.end - match.start;
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| +
|
| + var sourceFile = new SourceFile(string, url: sourceUrl);
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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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| + }
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| +
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| + // TODO(nweiz): Make this handle long lines more gracefully.
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| + /// Throws a [FormatException] describing that [name] is expected at the
|
| + /// current position in the string.
|
| + void _fail(String name) {
|
| + error("expected $name.", position: this.position, length: 0);
|
| + }
|
| +}
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|
|