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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