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1 // Copyright (c) 2009 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 
10 #include "base/basictypes.h"
11 #include "base/string16.h"
12 
13 // Escaping --------------------------------------------------------------------
14 
15 // Escape a file.  This includes:
16 // non-printable, non-7bit, and (including space)  "#%:<>?[\]^`{|}
17 std::string EscapePath(const std::string& path);
18 
19 // Escape application/x-www-form-urlencoded content.  This includes:
20 // non-printable, non-7bit, and (including space)  ?>=<;+'&%$#"![\]^`{|}
21 // Space is escaped as + and other special characters as %XX (hex).
22 std::string EscapeUrlEncodedData(const std::string& path);
23 
24 // Escape all non-ASCII input.
25 std::string EscapeNonASCII(const std::string& input);
26 
27 // Escapes characters in text suitable for use as an external protocol handler
28 // command.
29 // We %XX everything except alphanumerics and %-_.!~*'() and the restricted
30 // chracters (;/?:@&=+$,).
31 std::string EscapeExternalHandlerValue(const std::string& text);
32 
33 // Append the given character to the output string, escaping the character if
34 // the character would be interpretted as an HTML delimiter.
35 void AppendEscapedCharForHTML(char c, std::string* output);
36 
37 // Escape chars that might cause this text to be interpretted as HTML tags.
38 std::string EscapeForHTML(const std::string& text);
39 string16 EscapeForHTML(const string16& text);
40 
41 // Unescaping ------------------------------------------------------------------
42 
43 class UnescapeRule {
44  public:
45   // A combination of the following flags that is passed to the unescaping
46   // functions.
47   typedef uint32 Type;
48 
49   enum {
50     // Don't unescape anything at all.
51     NONE = 0,
52 
53     // Don't unescape anything special, but all normal unescaping will happen.
54     // This is a placeholder and can't be combined with other flags (since it's
55     // just the absence of them). All other unescape rules imply "normal" in
56     // addition to their special meaning. Things like escaped letters, digits,
57     // and most symbols will get unescaped with this mode.
58     NORMAL = 1,
59 
60     // Convert %20 to spaces. In some places where we're showing URLs, we may
61     // want this. In places where the URL may be copied and pasted out, then
62     // you wouldn't want this since it might not be interpreted in one piece
63     // by other applications.
64     SPACES = 2,
65 
66     // Unescapes various characters that will change the meaning of URLs,
67     // including '%', '+', '&', '/', '#'. If we unescaped these characters, the
68     // resulting URL won't be the same as the source one. This flag is used when
69     // generating final output like filenames for URLs where we won't be
70     // interpreting as a URL and want to do as much unescaping as possible.
71     URL_SPECIAL_CHARS = 4,
72 
73     // Unescapes control characters such as %01. This INCLUDES NULLs. This is
74     // used for rare cases such as data: URL decoding where the result is binary
75     // data. You should not use this for normal URLs!
76     CONTROL_CHARS = 8,
77 
78     // URL queries use "+" for space. This flag controls that replacement.
79     REPLACE_PLUS_WITH_SPACE = 16,
80   };
81 };
82 
83 // Unescapes |escaped_text| and returns the result.
84 // Unescaping consists of looking for the exact pattern "%XX", where each X is
85 // a hex digit, and converting to the character with the numerical value of
86 // those digits. Thus "i%20=%203%3b" unescapes to "i = 3;".
87 //
88 // Watch out: this doesn't necessarily result in the correct final result,
89 // because the encoding may be unknown. For example, the input might be ASCII,
90 // which, after unescaping, is supposed to be interpreted as UTF-8, and then
91 // converted into full wide chars. This function won't tell you if any
92 // conversions need to take place, it only unescapes.
93 std::string UnescapeURLComponent(const std::string& escaped_text,
94                                  UnescapeRule::Type rules);
95 string16 UnescapeURLComponent(const string16& escaped_text,
96                               UnescapeRule::Type rules);
97 
98 // Unescapes the given substring as a URL, and then tries to interpret the
99 // result as being encoded as UTF-8. If the result is convertable into UTF-8, it
100 // will be returned as converted. If it is not, the original escaped string will
101 // be converted into a string16 and returned.
102 //
103 // |offset_for_adjustment| may be NULL; if not, it is an offset into |text| that
104 // will be adjusted to point at the same logical place in the result string.  If
105 // this isn't possible because it points into the middle of an escape sequence
106 // or past the end of the string, it will be set to string16::npos.
107 string16 UnescapeAndDecodeUTF8URLComponent(const std::string& text,
108                                            UnescapeRule::Type rules,
109                                            size_t* offset_for_adjustment);
110 
111 // Unescape the following ampersand character codes from |text|:
112 // &lt; &gt; &amp; &quot; &#39;
113 string16 UnescapeForHTML(const string16& text);
114 
115 // Deprecated ------------------------------------------------------------------
116 
117 // Escapes characters in text suitable for use as a query parameter value.
118 // We %XX everything except alphanumerics and -_.!~*'()
119 // Spaces change to "+" unless you pass usePlus=false.
120 // This is basically the same as encodeURIComponent in javascript.
121 // For the string16 version, we do a conversion to charset before encoding the
122 // string.  If the charset doesn't exist, we return false.
123 //
124 // TODO(brettw) bug 1201094: This function should be removed. See the bug for
125 // why and what callers should do instead.
126 std::string EscapeQueryParamValue(const std::string& text, bool use_plus);
127 bool EscapeQueryParamValue(const string16& text, const char* codepage,
128                            bool use_plus, string16* escaped);
129 
130 // A specialized version of EscapeQueryParamValue for wide strings that
131 // assumes the codepage is UTF8.  This is provided as a convenience.
132 //
133 // TODO(brettw) bug 1201094: This function should be removed. See the bug for
134 // why and what callers should do instead.
135 std::wstring EscapeQueryParamValueUTF8(const std::wstring& text, bool use_plus);
136 
137 #endif  // NET_BASE_ESCAPE_H_
138