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1 : // Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
2 : // for details. All rights reserved. Use of this source code is governed by a
3 : // BSD-style license that can be found in the LICENSE file.
4 :
5 : /// A library for broadly-useful functions and regular expressions for scanning
6 : /// HTTP entities.
7 : ///
8 : /// Many of the regular expressions come from [section 2.2 of the HTTP
9 : /// spec][spec].
10 : ///
11 : /// [spec]: http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html
12 : import 'package:string_scanner/string_scanner.dart';
13 :
14 : /// An HTTP token.
15 : final token = new RegExp(r'[^()<>@,;:"\\/[\]?={} \t\x00-\x1F\x7F]+');
16 :
17 : /// Linear whitespace.
18 : final _lws = new RegExp(r"(?:\r\n)?[ \t]+");
19 :
20 : /// A quoted string.
21 : final _quotedString = new RegExp(r'"(?:[^"\x00-\x1F\x7F]|\\.)*"');
22 :
23 : /// A quoted pair.
24 : final _quotedPair = new RegExp(r'\\(.)');
25 :
26 : /// A character that is *not* a valid HTTP token.
27 : final nonToken = new RegExp(r'[()<>@,;:"\\/\[\]?={} \t\x00-\x1F\x7F]');
28 :
29 : /// A regular expression matching any number of [_lws] productions in a row.
30 : final whitespace = new RegExp("(?:${_lws.pattern})*");
31 :
32 : /// Parses a list of elements, as in `1#element` in the HTTP spec.
33 : ///
34 : /// [scanner] is used to parse the elements, and [parseElement] is used to parse
35 : /// each one individually. The values returned by [parseElement] are collected
36 : /// in a list and returned.
37 : ///
38 : /// Once this is finished, [scanner] will be at the next non-LWS character in
39 : /// the string, or the end of the string.
40 : List/*<T>*/ parseList/*<T>*/(StringScanner scanner, /*=T*/ parseElement()) {
41 0 : var result = /*<T>*/[];
42 :
43 : // Consume initial empty values.
44 0 : while (scanner.scan(",")) {
45 0 : scanner.scan(whitespace);
46 : }
47 :
48 0 : result.add(parseElement());
49 0 : scanner.scan(whitespace);
50 :
51 0 : while (scanner.scan(",")) {
52 0 : scanner.scan(whitespace);
53 :
54 : // Empty elements are allowed, but excluded from the results.
55 0 : if (scanner.matches(",") || scanner.isDone) continue;
56 :
57 0 : result.add(parseElement());
58 0 : scanner.scan(whitespace);
59 : }
60 :
61 : return result;
62 : }
63 :
64 : /// Parses a single quoted string, and returns its contents.
65 : ///
66 : /// If [name] is passed, it's used to describe the expected value if it's not
67 : /// found.
68 : String expectQuotedString(StringScanner scanner, {String name}) {
69 : if (name == null) name = "quoted string";
70 0 : scanner.expect(_quotedString, name: name);
71 0 : var string = scanner.lastMatch[0];
72 : return string
73 0 : .substring(1, string.length - 1)
74 0 : .replaceAllMapped(_quotedPair, (match) => match[1]);
75 : }
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