dirs_sys/
xdg_user_dirs.rs

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1use std::collections::HashMap;
2use std::ffi::OsString;
3use std::fs;
4use std::io::{self, Read};
5use std::os::unix::ffi::OsStringExt;
6use std::path::{Path, PathBuf};
7use std::str;
8
9use option_ext::OptionExt;
10
11/// Returns all XDG user directories obtained from $(XDG_CONFIG_HOME)/user-dirs.dirs.
12pub fn all(home_dir_path: &Path, user_dir_file_path: &Path) -> HashMap<String, PathBuf> {
13    let bytes = read_all(user_dir_file_path).unwrap_or(Vec::new());
14    parse_user_dirs(home_dir_path, None, &bytes)
15}
16
17/// Returns a single XDG user directory obtained from $(XDG_CONFIG_HOME)/user-dirs.dirs.
18pub fn single(home_dir_path: &Path, user_dir_file_path: &Path, user_dir_name: &str) -> HashMap<String, PathBuf> {
19    let bytes = read_all(user_dir_file_path).unwrap_or(Vec::new());
20    parse_user_dirs(home_dir_path, Some(user_dir_name), &bytes)
21}
22
23fn parse_user_dirs(home_dir: &Path, user_dir: Option<&str>, bytes: &[u8]) -> HashMap<String, PathBuf> {
24    let mut user_dirs = HashMap::new();
25
26    for line in bytes.split(|b| *b == b'\n') {
27        let mut single_dir_found = false;
28        let (key, value) = match split_once(line, b'=') {
29            Some(kv) => kv,
30            None => continue,
31        };
32
33        let key = trim_blank(key);
34        let key = if key.starts_with(b"XDG_") && key.ends_with(b"_DIR") {
35            match str::from_utf8(&key[4..key.len()-4]) {
36                Ok(key) =>
37                    if user_dir.contains(&key) {
38                        single_dir_found = true;
39                        key
40                    } else if user_dir.is_none() {
41                        key
42                    } else {
43                        continue
44                    },
45                Err(_)  => continue,
46            }
47        } else {
48            continue
49        };
50
51        // xdg-user-dirs-update uses double quotes and we don't support anything else.
52        let value = trim_blank(value);
53        let mut value = if value.starts_with(b"\"") && value.ends_with(b"\"") {
54            &value[1..value.len()-1]
55        } else {
56            continue
57        };
58
59        // Path should be either relative to the home directory or absolute.
60        let is_relative = if value == b"$HOME/" {
61            // "Note: To disable a directory, point it to the homedir."
62            // Source: https://www.freedesktop.org/wiki/Software/xdg-user-dirs/
63            // Additionally directory is reassigned to homedir when removed.
64            continue
65        } else if value.starts_with(b"$HOME/") {
66            value = &value[b"$HOME/".len()..];
67            true
68        } else if value.starts_with(b"/") {
69            false
70        } else {
71            continue
72        };
73
74        let value = OsString::from_vec(shell_unescape(value));
75
76        let path = if is_relative {
77            let mut path = PathBuf::from(&home_dir);
78            path.push(value);
79            path
80        } else {
81            PathBuf::from(value)
82        };
83
84        user_dirs.insert(key.to_owned(), path);
85        if single_dir_found {
86            break;
87        }
88    }
89
90    user_dirs
91}
92
93/// Reads the entire contents of a file into a byte vector.
94fn read_all(path: &Path) -> io::Result<Vec<u8>> {
95    let mut file = fs::File::open(path)?;
96    let mut bytes = Vec::with_capacity(1024);
97    file.read_to_end(&mut bytes)?;
98    Ok(bytes)
99}
100
101/// Returns bytes before and after first occurrence of separator.
102fn split_once(bytes: &[u8], separator: u8) -> Option<(&[u8], &[u8])> {
103    bytes.iter().position(|b| *b == separator).map(|i| {
104        (&bytes[..i], &bytes[i+1..])
105    })
106}
107
108/// Returns a slice with leading and trailing <blank> characters removed.
109fn trim_blank(bytes: &[u8]) -> &[u8] {
110    // Trim leading <blank> characters.
111    let i = bytes.iter().cloned().take_while(|b| *b == b' ' || *b == b'\t').count();
112    let bytes = &bytes[i..];
113
114    // Trim trailing <blank> characters.
115    let i = bytes.iter().cloned().rev().take_while(|b| *b == b' ' || *b == b'\t').count();
116    &bytes[..bytes.len()-i]
117}
118
119/// Unescape bytes escaped with POSIX shell double-quotes rules (as used by xdg-user-dirs-update).
120fn shell_unescape(escaped: &[u8]) -> Vec<u8> {
121    // We assume that byte string was created by xdg-user-dirs-update which
122    // escapes all characters that might potentially have special meaning,
123    // so there is no need to check if backslash is actually followed by
124    // $ ` " \ or a <newline>.
125
126    let mut unescaped: Vec<u8> = Vec::with_capacity(escaped.len());
127    let mut i = escaped.iter().cloned();
128
129    while let Some(b) = i.next() {
130        if b == b'\\' {
131            if let Some(b) = i.next() {
132                unescaped.push(b);
133            }
134        } else {
135            unescaped.push(b);
136        }
137    }
138
139    unescaped
140}
141
142#[cfg(test)]
143mod tests {
144    use std::collections::HashMap;
145    use std::path::{Path, PathBuf};
146
147    use super::{parse_user_dirs, shell_unescape, split_once, trim_blank};
148
149    #[test]
150    fn test_trim_blank() {
151        assert_eq!(b"x", trim_blank(b"x"));
152        assert_eq!(b"", trim_blank(b" \t  "));
153        assert_eq!(b"hello there", trim_blank(b" \t hello there \t "));
154        assert_eq!(b"\r\n", trim_blank(b"\r\n"));
155    }
156
157    #[test]
158    fn test_split_once() {
159        assert_eq!(None, split_once(b"a b c", b'='));
160        assert_eq!(Some((b"before".as_ref(), b"after".as_ref())), split_once(b"before=after", b'='));
161    }
162
163    #[test]
164    fn test_shell_unescape() {
165        assert_eq!(b"abc", shell_unescape(b"abc").as_slice());
166        assert_eq!(b"x\\y$z`", shell_unescape(b"x\\\\y\\$z\\`").as_slice());
167    }
168
169    #[test]
170    fn test_parse_empty() {
171        assert_eq!(HashMap::new(), parse_user_dirs(Path::new("/root/"), None, b""));
172        assert_eq!(HashMap::new(), parse_user_dirs(Path::new("/root/"), Some("MUSIC"), b""));
173    }
174
175    #[test]
176    fn test_absolute_path_is_accepted() {
177        let mut dirs = HashMap::new();
178        dirs.insert("MUSIC".to_owned(), PathBuf::from("/media/music"));
179        let bytes = br#"XDG_MUSIC_DIR="/media/music""#;
180        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
181        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
182    }
183
184    #[test]
185    fn test_relative_path_is_rejected() {
186        let dirs = HashMap::new();
187        let bytes = br#"XDG_MUSIC_DIR="music""#;
188        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
189        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
190    }
191
192    #[test]
193    fn test_relative_to_home() {
194        let mut dirs = HashMap::new();
195        dirs.insert("MUSIC".to_owned(), PathBuf::from("/home/john/Music"));
196        let bytes = br#"XDG_MUSIC_DIR="$HOME/Music""#;
197        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
198        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
199    }
200
201    #[test]
202    fn test_disabled_directory() {
203        let dirs = HashMap::new();
204        let bytes = br#"XDG_MUSIC_DIR="$HOME/""#;
205        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
206        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
207    }
208
209    #[test]
210    fn test_parse_user_dirs() {
211        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
212        dirs.insert("DESKTOP".to_string(), PathBuf::from("/home/bob/Desktop"));
213        dirs.insert("DOWNLOAD".to_string(), PathBuf::from("/home/bob/Downloads"));
214        dirs.insert("PICTURES".to_string(), PathBuf::from("/home/eve/pics"));
215
216        let bytes = br#"
217# This file is written by xdg-user-dirs-update
218# If you want to change or add directories, just edit the line you're
219# interested in. All local changes will be retained on the next run.
220# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
221# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
222# absolute path. No other format is supported.
223XDG_DESKTOP_DIR="$HOME/Desktop"
224XDG_DOWNLOAD_DIR="$HOME/Downloads"
225XDG_TEMPLATES_DIR=""
226XDG_PUBLICSHARE_DIR="$HOME"
227XDG_DOCUMENTS_DIR="$HOME/"
228XDG_PICTURES_DIR="/home/eve/pics"
229XDG_VIDEOS_DIR="$HOxyzME/Videos"
230"#;
231
232        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), None, bytes));
233
234        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
235        dirs.insert("DESKTOP".to_string(), PathBuf::from("/home/bob/Desktop"));
236        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("DESKTOP"), bytes));
237
238        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
239        dirs.insert("PICTURES".to_string(), PathBuf::from("/home/eve/pics"));
240        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("PICTURES"), bytes));
241
242        let dirs: HashMap<String, PathBuf> = HashMap::new();
243        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("TEMPLATES"), bytes));
244        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("PUBLICSHARE"), bytes));
245        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("DOCUMENTS"), bytes));
246        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("VIDEOS"), bytes));
247    }
248}
dirs_sys/xdg_user_dirs.rs

dirs_sys/
xdg_user_dirs.rs
