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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef NET_BASE_ESCAPE_H_
6 #define NET_BASE_ESCAPE_H_
7 
8 #include <string>
9 #include <vector>
10 
11 #include "base/basictypes.h"
12 #include "base/strings/string16.h"
13 #include "base/strings/utf_offset_string_conversions.h"
14 #include "net/base/net_export.h"
15 
16 namespace net {
17 
18 // Escaping --------------------------------------------------------------------
19 
20 // Escapes characters in text suitable for use as a query parameter value.
21 // We %XX everything except alphanumerics and -_.!~*'()
22 // Spaces change to "+" unless you pass usePlus=false.
23 // This is basically the same as encodeURIComponent in javascript.
24 NET_EXPORT std::string EscapeQueryParamValue(const std::string& text,
25                                              bool use_plus);
26 
27 // Escapes a partial or complete file/pathname.  This includes:
28 // non-printable, non-7bit, and (including space)  "#%:<>?[\]^`{|}
29 // For the base::string16 version, we attempt a conversion to |codepage| before
30 // encoding the string.  If this conversion fails, we return false.
31 NET_EXPORT std::string EscapePath(const std::string& path);
32 
33 // Escapes application/x-www-form-urlencoded content.  This includes:
34 // non-printable, non-7bit, and (including space)  ?>=<;+'&%$#"![\]^`{|}
35 // Space is escaped as + (if use_plus is true) and other special characters
36 // as %XX (hex).
37 NET_EXPORT std::string EscapeUrlEncodedData(const std::string& path,
38                                             bool use_plus);
39 
40 // Escapes all non-ASCII input.
41 NET_EXPORT std::string EscapeNonASCII(const std::string& input);
42 
43 // Escapes characters in text suitable for use as an external protocol handler
44 // command.
45 // We %XX everything except alphanumerics and %-_.!~*'() and the restricted
46 // chracters (;/?:@&=+$,).
47 NET_EXPORT std::string EscapeExternalHandlerValue(const std::string& text);
48 
49 // Appends the given character to the output string, escaping the character if
50 // the character would be interpretted as an HTML delimiter.
51 NET_EXPORT void AppendEscapedCharForHTML(char c, std::string* output);
52 
53 // Escapes chars that might cause this text to be interpretted as HTML tags.
54 NET_EXPORT std::string EscapeForHTML(const std::string& text);
55 NET_EXPORT base::string16 EscapeForHTML(const base::string16& text);
56 
57 // Unescaping ------------------------------------------------------------------
58 
59 class UnescapeRule {
60  public:
61   // A combination of the following flags that is passed to the unescaping
62   // functions.
63   typedef uint32 Type;
64 
65   enum {
66     // Don't unescape anything at all.
67     NONE = 0,
68 
69     // Don't unescape anything special, but all normal unescaping will happen.
70     // This is a placeholder and can't be combined with other flags (since it's
71     // just the absence of them). All other unescape rules imply "normal" in
72     // addition to their special meaning. Things like escaped letters, digits,
73     // and most symbols will get unescaped with this mode.
74     NORMAL = 1,
75 
76     // Convert %20 to spaces. In some places where we're showing URLs, we may
77     // want this. In places where the URL may be copied and pasted out, then
78     // you wouldn't want this since it might not be interpreted in one piece
79     // by other applications.
80     SPACES = 2,
81 
82     // Unescapes various characters that will change the meaning of URLs,
83     // including '%', '+', '&', '/', '#'. If we unescaped these characters, the
84     // resulting URL won't be the same as the source one. This flag is used when
85     // generating final output like filenames for URLs where we won't be
86     // interpreting as a URL and want to do as much unescaping as possible.
87     URL_SPECIAL_CHARS = 4,
88 
89     // Unescapes control characters such as %01. This INCLUDES NULLs. This is
90     // used for rare cases such as data: URL decoding where the result is binary
91     // data. You should not use this for normal URLs!
92     CONTROL_CHARS = 8,
93 
94     // URL queries use "+" for space. This flag controls that replacement.
95     REPLACE_PLUS_WITH_SPACE = 16,
96   };
97 };
98 
99 // Unescapes |escaped_text| and returns the result.
100 // Unescaping consists of looking for the exact pattern "%XX", where each X is
101 // a hex digit, and converting to the character with the numerical value of
102 // those digits. Thus "i%20=%203%3b" unescapes to "i = 3;".
103 //
104 // Watch out: this doesn't necessarily result in the correct final result,
105 // because the encoding may be unknown. For example, the input might be ASCII,
106 // which, after unescaping, is supposed to be interpreted as UTF-8, and then
107 // converted into full UTF-16 chars. This function won't tell you if any
108 // conversions need to take place, it only unescapes.
109 NET_EXPORT std::string UnescapeURLComponent(const std::string& escaped_text,
110                                             UnescapeRule::Type rules);
111 NET_EXPORT base::string16 UnescapeURLComponent(
112     const base::string16& escaped_text,
113     UnescapeRule::Type rules);
114 
115 // Unescapes the given substring as a URL, and then tries to interpret the
116 // result as being encoded as UTF-8. If the result is convertable into UTF-8, it
117 // will be returned as converted. If it is not, the original escaped string will
118 // be converted into a base::string16 and returned.  |adjustments| provides
119 // information on how the original string was adjusted to get the string
120 // returned.
121 NET_EXPORT base::string16 UnescapeAndDecodeUTF8URLComponent(
122     const std::string& text,
123     UnescapeRule::Type rules);
124 NET_EXPORT base::string16 UnescapeAndDecodeUTF8URLComponentWithAdjustments(
125     const std::string& text,
126     UnescapeRule::Type rules,
127     base::OffsetAdjuster::Adjustments* adjustments);
128 
129 // Unescapes the following ampersand character codes from |text|:
130 // &lt; &gt; &amp; &quot; &#39;
131 NET_EXPORT base::string16 UnescapeForHTML(const base::string16& text);
132 
133 }  // namespace net
134 
135 #endif  // NET_BASE_ESCAPE_H_
136