Extract an http_parser package from shelf.

pkg/shelf/lib/src/media_type.dart

Index: pkg/shelf/lib/src/media_type.dart
diff --git a/pkg/shelf/lib/src/media_type.dart b/pkg/shelf/lib/src/media_type.dart
deleted file mode 100644
index a1f5ed260e7fb96c7729b2c0c04e912abc8bdf46..0000000000000000000000000000000000000000
--- a/pkg/shelf/lib/src/media_type.dart
+++ /dev/null
@@ -1,158 +0,0 @@
-// 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 shelf.media_type;
-
-import 'package:collection/collection.dart';
-import 'package:string_scanner/string_scanner.dart';
-
-// All of the following regular expressions come from section 2.2 of the HTTP
-// spec: http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html
-final _lws = new RegExp(r"(?:\r\n)?[ \t]+");
-final _token = new RegExp(r'[^()<>@,;:"\\/[\]?={} \t\x00-\x1F\x7F]+');
-final _quotedString = new RegExp(r'"(?:[^"\x00-\x1F\x7F]|\\.)*"');
-final _quotedPair = new RegExp(r'\\(.)');
-
-/// A regular expression matching any number of [_lws] productions in a row.
-final _whitespace = new RegExp("(?:${_lws.pattern})*");
-
-/// A regular expression matching a character that is not a valid HTTP token.
-final _nonToken = new RegExp(r'[()<>@,;:"\\/\[\]?={} \t\x00-\x1F\x7F]');
-
-/// A regular expression matching a character that needs to be backslash-escaped
-/// in a quoted string.
-final _escapedChar = new RegExp(r'["\x00-\x1F\x7F]');
-
-/// A class representing an HTTP media type, as used in Accept and Content-Type
-/// headers.
-class MediaType {
-  /// The primary identifier of the MIME type.
-  final String type;
-
-  /// The secondary identifier of the MIME type.
-  final String subtype;
-
-  /// The parameters to the media type.
-  ///
-  /// This map is immutable.
-  final Map<String, String> parameters;
-
-  /// The media type's MIME type.
-  String get mimeType => "$type/$subtype";
-
-  /// Parses a media type.
-  ///
-  /// This will throw a FormatError if the media type is invalid.
-  factory MediaType.parse(String mediaType) {
-    // This parsing is based on sections 3.6 and 3.7 of the HTTP spec:
-    // http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html.
-    try {
-      var scanner = new StringScanner(mediaType);
-      scanner.scan(_whitespace);
-      scanner.expect(_token);
-      var type = scanner.lastMatch[0];
-      scanner.expect('/');
-      scanner.expect(_token);
-      var subtype = scanner.lastMatch[0];
-      scanner.scan(_whitespace);
-
-      var parameters = {};
-      while (scanner.scan(';')) {
-        scanner.scan(_whitespace);
-        scanner.expect(_token);
-        var attribute = scanner.lastMatch[0];
-        scanner.expect('=');
-
-        var value;
-        if (scanner.scan(_token)) {
-          value = scanner.lastMatch[0];
-        } else {
-          scanner.expect(_quotedString);
-          var quotedString = scanner.lastMatch[0];
-          value = quotedString.substring(1, quotedString.length - 1).
-              replaceAllMapped(_quotedPair, (match) => match[1]);
-        }
-
-        scanner.scan(_whitespace);
-        parameters[attribute] = value;
-      }
-
-      scanner.expectDone();
-      return new MediaType(type, subtype, parameters);
-    } on FormatException catch (error) {
-      throw new FormatException(
-          'Invalid media type "$mediaType": ${error.message}');
-    }
-  }
-
-  MediaType(this.type, this.subtype, [Map<String, String> parameters])
-      : this.parameters = new UnmodifiableMapView(
-          parameters == null ? {} : new Map.from(parameters));
-
-  /// Returns a copy of this [MediaType] with some fields altered.
-  ///
-  /// [type] and [subtype] alter the corresponding fields. [mimeType] is parsed
-  /// and alters both the [type] and [subtype] fields; it cannot be passed along
-  /// with [type] or [subtype].
-  ///
-  /// [parameters] overwrites and adds to the corresponding field. If
-  /// [clearParameters] is passed, it replaces the corresponding field entirely
-  /// instead.
-  MediaType change({String type, String subtype, String mimeType,
-      Map<String, String> parameters, bool clearParameters: false}) {
-    if (mimeType != null) {
-      if (type != null) {
-        throw new ArgumentError("You may not pass both [type] and [mimeType].");
-      } else if (subtype != null) {
-        throw new ArgumentError("You may not pass both [subtype] and "
-            "[mimeType].");
-      }
-
-      var segments = mimeType.split('/');
-      if (segments.length != 2) {
-        throw new FormatException('Invalid mime type "$mimeType".');
-      }
-
-      type = segments[0];
-      subtype = segments[1];
-    }
-
-    if (type == null) type = this.type;
-    if (subtype == null) subtype = this.subtype;
-    if (parameters == null) parameters = {};
-
-    if (!clearParameters) {
-      var newParameters = parameters;
-      parameters = new Map.from(this.parameters);
-      parameters.addAll(newParameters);
-    }
-
-    return new MediaType(type, subtype, parameters);
-  }
-
-  /// Converts the media type to a string.
-  ///
-  /// This will produce a valid HTTP media type.
-  String toString() {
-    var buffer = new StringBuffer()
-        ..write(type)
-        ..write("/")
-        ..write(subtype);
-
-    parameters.forEach((attribute, value) {
-      buffer.write("; $attribute=");
-      if (_nonToken.hasMatch(value)) {
-        buffer
-          ..write('"')
-          ..write(value.replaceAllMapped(
-              _escapedChar, (match) => "\\" + match[0]))
-          ..write('"');
-      } else {
-        buffer.write(value);
-      }
-    });
-
-    return buffer.toString();
-  }
-}