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1 // Copyright 2014 The Chromium Authors
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_FILENAME_UTIL_H_
6 #define NET_BASE_FILENAME_UTIL_H_
7 
8 #include <string>
9 
10 #include "base/files/file_path.h"
11 #include "net/base/net_export.h"
12 
13 class GURL;
14 
15 namespace base {
16 class FilePath;
17 }
18 
19 namespace net {
20 
21 // Given the full path to a file name, creates a file: URL. The returned URL
22 // may not be valid if the input is malformed.
23 NET_EXPORT GURL FilePathToFileURL(const base::FilePath& path);
24 
25 // Converts a file: URL back to a filename that can be passed to the OS. The
26 // file URL must be well-formed (GURL::is_valid() must return true); we don't
27 // handle degenerate cases here. Returns true on success, false if |url| is
28 // invalid or the file path cannot be extracted from |url|.
29 // On failure, *file_path will be empty.
30 //
31 // Do not call this with a |url| that doesn't have a file:// scheme.
32 // The implementation is specific to the platform filesystem, and not
33 // applicable to other schemes.
34 NET_EXPORT bool FileURLToFilePath(const GURL& url, base::FilePath* file_path);
35 
36 // Generates a filename using the first successful method from the following (in
37 // order):
38 //
39 // 1) The raw Content-Disposition header in |content_disposition| as read from
40 //    the network.  |referrer_charset| is used to decode non-ASCII strings.
41 // 2) |suggested_name| if specified.  |suggested_name| is assumed to be in
42 //    UTF-8.
43 // 3) The filename extracted from the |url|.  |referrer_charset| will be used to
44 //    interpret the URL if there are non-ascii characters.The file extension for
45 //    filenames extracted from the URL are considered unreliable if the URL
46 //    contains a query string. If a MIME type is available (i.e. |mime_type| is
47 //    not empty) and that MIME type has a preferred extension, then the
48 //    resulting filename will have that preferred extension.
49 // 4) |default_name|.  If non-empty, |default_name| is assumed to be a filename
50 //    and shouldn't contain a path.  |default_name| is not subject to validation
51 //    or sanitization, and therefore shouldn't be a user supplied string.
52 // 5) The hostname portion from the |url|
53 //
54 // Then, leading and trailing '.'s will be removed.  On Windows, trailing spaces
55 // are also removed.  The string "download" is the final fallback if no filename
56 // is found or the filename is empty.
57 //
58 // Any illegal characters in the filename will be replaced by '-'.  If the
59 // filename doesn't contain an extension, and a |mime_type| is specified, the
60 // preferred extension for the |mime_type| will be appended to the filename.
61 // The resulting filename is then checked against a list of reserved names on
62 // Windows.  If the name is reserved, an underscore will be prepended to the
63 // filename.
64 //
65 // Note: |mime_type| should only be specified if this function is called from a
66 // thread that allows IO.
67 NET_EXPORT std::u16string GetSuggestedFilename(
68     const GURL& url,
69     const std::string& content_disposition,
70     const std::string& referrer_charset,
71     const std::string& suggested_name,
72     const std::string& mime_type,
73     const std::string& default_name);
74 
75 // Similar to GetSuggestedFilename(), but returns a FilePath.
76 NET_EXPORT base::FilePath GenerateFileName(
77     const GURL& url,
78     const std::string& content_disposition,
79     const std::string& referrer_charset,
80     const std::string& suggested_name,
81     const std::string& mime_type,
82     const std::string& default_name);
83 
84 // Similar to GetSuggestedFilename(). If |should_replace_extension| is true, the
85 // file extension extracted from a URL will always be considered unreliable and
86 // the file extension will be determined by |mime_type|.
87 NET_EXPORT base::FilePath GenerateFileName(
88     const GURL& url,
89     const std::string& content_disposition,
90     const std::string& referrer_charset,
91     const std::string& suggested_name,
92     const std::string& mime_type,
93     const std::string& default_name,
94     bool should_replace_extension);
95 
96 // Valid components:
97 // * are not empty
98 // * are not Windows reserved names (CON, NUL.zip, etc.)
99 // * do not have trailing separators
100 // * do not equal kCurrentDirectory
101 // * do not reference the parent directory
102 // * do not contain illegal characters
103 // * do not end with Windows shell-integrated extensions (even on posix)
104 // * do not begin with '.' (which would hide them in most file managers)
105 // * do not end with ' ' or '.'
106 NET_EXPORT bool IsSafePortablePathComponent(const base::FilePath& component);
107 
108 // Basenames of valid relative paths are IsSafePortableBasename(), and internal
109 // path components of valid relative paths are valid path components as
110 // described above IsSafePortableBasename(). Valid relative paths are not
111 // absolute paths.
112 NET_EXPORT bool IsSafePortableRelativePath(const base::FilePath& path);
113 
114 // Ensures that the filename and extension is safe to use in the filesystem.
115 //
116 // Assumes that |file_path| already contains a valid path or file name.  On
117 // Windows if the extension causes the file to have an unsafe interaction with
118 // the shell (see net_util::IsShellIntegratedExtension()), then it will be
119 // replaced by the string 'download'.  If |file_path| doesn't contain an
120 // extension or |ignore_extension| is true then the preferred extension, if one
121 // exists, for |mime_type| will be used as the extension.
122 //
123 // On Windows, the filename will be checked against a set of reserved names, and
124 // if so, an underscore will be prepended to the name.
125 //
126 // |file_name| can either be just the file name or it can be a full path to a
127 // file.
128 //
129 // Note: |mime_type| should only be non-empty if this function is called from a
130 // thread that allows IO.
131 NET_EXPORT void GenerateSafeFileName(const std::string& mime_type,
132                                      bool ignore_extension,
133                                      base::FilePath* file_path);
134 
135 // Returns whether the specified file name is a reserved name on Windows.
136 // This includes names like "com2.zip" (which correspond to devices) and
137 // desktop.ini and thumbs.db which have special meaning to the Windows shell.
138 // Even on other platforms, this will return whether or not a file name is
139 // reserved on Windows.
140 NET_EXPORT bool IsReservedNameOnWindows(
141     const base::FilePath::StringType& filename);
142 
143 }  // namespace net
144 
145 #endif  // NET_BASE_FILENAME_UTIL_H_
146