Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/string_scanner/lib/src/string_scanner.dart

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