dirs_sys/
xdg_user_dirs.rs

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
9/// Returns all XDG user directories obtained from $(XDG_CONFIG_HOME)/user-dirs.dirs.
10pub fn all(home_dir_path: &Path, user_dir_file_path: &Path) -> HashMap<String, PathBuf> {
11    let bytes = read_all(user_dir_file_path).unwrap_or(Vec::new());
12    parse_user_dirs(home_dir_path, None, &bytes)
13}
14
15/// Returns a single XDG user directory obtained from $(XDG_CONFIG_HOME)/user-dirs.dirs.
16pub fn single(home_dir_path: &Path, user_dir_file_path: &Path, user_dir_name: &str) -> HashMap<String, PathBuf> {
17    let bytes = read_all(user_dir_file_path).unwrap_or(Vec::new());
18    parse_user_dirs(home_dir_path, Some(user_dir_name), &bytes)
19}
20
21fn parse_user_dirs(home_dir: &Path, user_dir: Option<&str>, bytes: &[u8]) -> HashMap<String, PathBuf> {
22    let mut user_dirs = HashMap::new();
23
24    for line in bytes.split(|b| *b == b'\n') {
25        let mut single_dir_found = false;
26        let (key, value) = match split_once(line, b'=') {
27            Some(kv) => kv,
28            None => continue,
29        };
30
31        let key = trim_blank(key);
32        let key = if key.starts_with(b"XDG_") && key.ends_with(b"_DIR") {
33            match str::from_utf8(&key[4..key.len()-4]) {
34                Ok(key) =>
35                    if user_dir.is_some() && option_contains(user_dir, key) {
36                        single_dir_found = true;
37                        key
38                    } else if user_dir.is_none() {
39                        key
40                    } else {
41                        continue
42                    },
43                Err(_)  => continue,
44            }
45        } else {
46            continue
47        };
48
49        // xdg-user-dirs-update uses double quotes and we don't support anything else.
50        let value = trim_blank(value);
51        let mut value = if value.starts_with(b"\"") && value.ends_with(b"\"") {
52            &value[1..value.len()-1]
53        } else {
54            continue
55        };
56
57        // Path should be either relative to the home directory or absolute.
58        let is_relative = if value == b"$HOME/" {
59            // "Note: To disable a directory, point it to the homedir."
60            // Source: https://www.freedesktop.org/wiki/Software/xdg-user-dirs/
61            // Additionally directory is reassigned to homedir when removed.
62            continue
63        } else if value.starts_with(b"$HOME/") {
64            value = &value[b"$HOME/".len()..];
65            true
66        } else if value.starts_with(b"/") {
67            false
68        } else {
69            continue
70        };
71
72        let value = OsString::from_vec(shell_unescape(value));
73
74        let path = if is_relative {
75            let mut path = PathBuf::from(&home_dir);
76            path.push(value);
77            path
78        } else {
79            PathBuf::from(value)
80        };
81
82        user_dirs.insert(key.to_owned(), path);
83        if single_dir_found {
84            break;
85        }
86    }
87
88    user_dirs
89}
90
91/// Reads the entire contents of a file into a byte vector.
92fn read_all(path: &Path) -> io::Result<Vec<u8>> {
93    let mut file = fs::File::open(path)?;
94    let mut bytes = Vec::with_capacity(1024);
95    file.read_to_end(&mut bytes)?;
96    Ok(bytes)
97}
98
99/// Returns bytes before and after first occurrence of separator.
100fn split_once(bytes: &[u8], separator: u8) -> Option<(&[u8], &[u8])> {
101    bytes.iter().position(|b| *b == separator).map(|i| {
102        (&bytes[..i], &bytes[i+1..])
103    })
104}
105
106/// Returns a slice with leading and trailing <blank> characters removed.
107fn trim_blank(bytes: &[u8]) -> &[u8] {
108    // Trim leading <blank> characters.
109    let i = bytes.iter().cloned().take_while(|b| *b == b' ' || *b == b'\t').count();
110    let bytes = &bytes[i..];
111
112    // Trim trailing <blank> characters.
113    let i = bytes.iter().cloned().rev().take_while(|b| *b == b' ' || *b == b'\t').count();
114    &bytes[..bytes.len()-i]
115}
116
117/// Unescape bytes escaped with POSIX shell double-quotes rules (as used by xdg-user-dirs-update).
118fn shell_unescape(escaped: &[u8]) -> Vec<u8> {
119    // We assume that byte string was created by xdg-user-dirs-update which
120    // escapes all characters that might potentially have special meaning,
121    // so there is no need to check if backslash is actually followed by
122    // $ ` " \ or a <newline>.
123
124    let mut unescaped: Vec<u8> = Vec::with_capacity(escaped.len());
125    let mut i = escaped.iter().cloned();
126
127    while let Some(b) = i.next() {
128        if b == b'\\' {
129            if let Some(b) = i.next() {
130                unescaped.push(b);
131            }
132        } else {
133            unescaped.push(b);
134        }
135    }
136
137    unescaped
138}
139
140fn option_contains<T : PartialEq>(option: Option<T>, value: T) -> bool {
141    match option {
142        Some(val) => val == value,
143        None => false
144    }
145}
146
147#[cfg(test)]
148mod tests {
149    use std::collections::HashMap;
150    use std::path::{Path, PathBuf};
151    use super::{trim_blank, shell_unescape, split_once, parse_user_dirs};
152
153    #[test]
154    fn test_trim_blank() {
155        assert_eq!(b"x", trim_blank(b"x"));
156        assert_eq!(b"", trim_blank(b" \t  "));
157        assert_eq!(b"hello there", trim_blank(b" \t hello there \t "));
158        assert_eq!(b"\r\n", trim_blank(b"\r\n"));
159    }
160
161    #[test]
162    fn test_split_once() {
163        assert_eq!(None, split_once(b"a b c", b'='));
164        assert_eq!(Some((b"before".as_ref(), b"after".as_ref())), split_once(b"before=after", b'='));
165    }
166
167    #[test]
168    fn test_shell_unescape() {
169        assert_eq!(b"abc", shell_unescape(b"abc").as_slice());
170        assert_eq!(b"x\\y$z`", shell_unescape(b"x\\\\y\\$z\\`").as_slice());
171    }
172
173    #[test]
174    fn test_parse_empty() {
175        assert_eq!(HashMap::new(), parse_user_dirs(Path::new("/root/"), None, b""));
176        assert_eq!(HashMap::new(), parse_user_dirs(Path::new("/root/"), Some("MUSIC"), b""));
177    }
178
179    #[test]
180    fn test_absolute_path_is_accepted() {
181        let mut dirs = HashMap::new();
182        dirs.insert("MUSIC".to_owned(), PathBuf::from("/media/music"));
183        let bytes = br#"XDG_MUSIC_DIR="/media/music""#;
184        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
185        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
186    }
187
188    #[test]
189    fn test_relative_path_is_rejected() {
190        let dirs = HashMap::new();
191        let bytes = br#"XDG_MUSIC_DIR="music""#;
192        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
193        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
194    }
195
196    #[test]
197    fn test_relative_to_home() {
198        let mut dirs = HashMap::new();
199        dirs.insert("MUSIC".to_owned(), PathBuf::from("/home/john/Music"));
200        let bytes = br#"XDG_MUSIC_DIR="$HOME/Music""#;
201        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
202        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
203    }
204
205    #[test]
206    fn test_disabled_directory() {
207        let dirs = HashMap::new();
208        let bytes = br#"XDG_MUSIC_DIR="$HOME/""#;
209        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
210        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
211    }
212
213    #[test]
214    fn test_parse_user_dirs() {
215        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
216        dirs.insert("DESKTOP".to_string(), PathBuf::from("/home/bob/Desktop"));
217        dirs.insert("DOWNLOAD".to_string(), PathBuf::from("/home/bob/Downloads"));
218        dirs.insert("PICTURES".to_string(), PathBuf::from("/home/eve/pics"));
219
220        let bytes = br#"
221# This file is written by xdg-user-dirs-update
222# If you want to change or add directories, just edit the line you're
223# interested in. All local changes will be retained on the next run.
224# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
225# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
226# absolute path. No other format is supported.
227XDG_DESKTOP_DIR="$HOME/Desktop"
228XDG_DOWNLOAD_DIR="$HOME/Downloads"
229XDG_TEMPLATES_DIR=""
230XDG_PUBLICSHARE_DIR="$HOME"
231XDG_DOCUMENTS_DIR="$HOME/"
232XDG_PICTURES_DIR="/home/eve/pics"
233XDG_VIDEOS_DIR="$HOxyzME/Videos"
234"#;
235
236        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), None, bytes));
237
238        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
239        dirs.insert("DESKTOP".to_string(), PathBuf::from("/home/bob/Desktop"));
240        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("DESKTOP"), bytes));
241
242        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
243        dirs.insert("PICTURES".to_string(), PathBuf::from("/home/eve/pics"));
244        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("PICTURES"), bytes));
245
246        let dirs: HashMap<String, PathBuf> = HashMap::new();
247        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("TEMPLATES"), bytes));
248        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("PUBLICSHARE"), bytes));
249        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("DOCUMENTS"), bytes));
250        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("VIDEOS"), bytes));
251    }
252}
dirs_sys/xdg_user_dirs.rs

dirs_sys/
xdg_user_dirs.rs
