net/base/escape.h

   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 (;/?:@&=+$,#[]) and a valid percent escape sequence (%XX).
  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. This flag also unescapes BiDi control characters.
  92     //
  93     // DO NOT use CONTROL_CHARS if the URL is going to be displayed in the UI
  94     // for security reasons.
  95     CONTROL_CHARS = 8,
  96
  97     // URL queries use "+" for space. This flag controls that replacement.
  98     REPLACE_PLUS_WITH_SPACE = 16,
  99   };
 100 };
 101
 102 // Unescapes |escaped_text| and returns the result.
 103 // Unescaping consists of looking for the exact pattern "%XX", where each X is
 104 // a hex digit, and converting to the character with the numerical value of
 105 // those digits. Thus "i%20=%203%3b" unescapes to "i = 3;".
 106 //
 107 // Watch out: this doesn't necessarily result in the correct final result,
 108 // because the encoding may be unknown. For example, the input might be ASCII,
 109 // which, after unescaping, is supposed to be interpreted as UTF-8, and then
 110 // converted into full UTF-16 chars. This function won't tell you if any
 111 // conversions need to take place, it only unescapes.
 112 NET_EXPORT std::string UnescapeURLComponent(const std::string& escaped_text,
 113                                             UnescapeRule::Type rules);
 114 NET_EXPORT base::string16 UnescapeURLComponent(
 115     const base::string16& escaped_text,
 116     UnescapeRule::Type rules);
 117
 118 // Unescapes the given substring as a URL, and then tries to interpret the
 119 // result as being encoded as UTF-8. If the result is convertable into UTF-8, it
 120 // will be returned as converted. If it is not, the original escaped string will
 121 // be converted into a base::string16 and returned.  |adjustments| provides
 122 // information on how the original string was adjusted to get the string
 123 // returned.
 124 NET_EXPORT base::string16 UnescapeAndDecodeUTF8URLComponent(
 125     const std::string& text,
 126     UnescapeRule::Type rules);
 127 NET_EXPORT base::string16 UnescapeAndDecodeUTF8URLComponentWithAdjustments(
 128     const std::string& text,
 129     UnescapeRule::Type rules,
 130     base::OffsetAdjuster::Adjustments* adjustments);
 131
 132 // Unescapes the following ampersand character codes from |text|:
 133 // &lt; &gt; &amp; &quot; &#39;
 134 NET_EXPORT base::string16 UnescapeForHTML(const base::string16& text);
 135
 136 }  // namespace net
 137
 138 #endif  // NET_BASE_ESCAPE_H_