Files
abomonation
abomonation_derive
ansi_term
async_trait
atty
bincode
bitflags
byteorder
bytes
cfg_if
chrono
clap
dirs
dirs_sys
erdos
fixedbitset
fnv
futures
futures_channel
futures_core
futures_executor
futures_io
futures_macro
futures_sink
futures_task
futures_util
async_await
future
io
lock
sink
stream
task
indexmap
iovec
lazy_static
libc
log
memchr
mio
net2
num_cpus
num_integer
num_traits
petgraph
pin_project_lite
pin_utils
proc_macro2
proc_macro_hack
proc_macro_nested
quote
rand
rand_chacha
rand_core
rand_hc
rand_isaac
rand_jitter
rand_os
rand_pcg
rand_xorshift
serde
serde_derive
sha1
slab
slog
slog_term
strsim
syn
synstructure
term
textwrap
thread_local
time
tokio
future
io
loom
macros
net
park
runtime
stream
sync
task
time
util
tokio_macros
tokio_serde
tokio_serde_bincode
tokio_util
unicode_width
unicode_xid
uuid
vec_map
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
use std::collections::HashMap;
use std::ffi::OsString;
use std::fs;
use std::io::{self, Read};
use std::os::unix::ffi::OsStringExt;
use std::path::{Path, PathBuf};
use std::str;

/// Returns all XDG user directories obtained from $(XDG_CONFIG_HOME)/user-dirs.dirs.
pub fn all(home_dir_path: &Path, user_dir_file_path: &Path) -> HashMap<String, PathBuf> {
    let bytes = read_all(user_dir_file_path).unwrap_or(Vec::new());
    parse_user_dirs(home_dir_path, None, &bytes)
}

/// Returns a single XDG user directory obtained from $(XDG_CONFIG_HOME)/user-dirs.dirs.
pub fn single(home_dir_path: &Path, user_dir_file_path: &Path, user_dir_name: &str) -> HashMap<String, PathBuf> {
    let bytes = read_all(user_dir_file_path).unwrap_or(Vec::new());
    parse_user_dirs(home_dir_path, Some(user_dir_name), &bytes)
}

fn parse_user_dirs(home_dir: &Path, user_dir: Option<&str>, bytes: &[u8]) -> HashMap<String, PathBuf> {
    let mut user_dirs = HashMap::new();

    for line in bytes.split(|b| *b == b'\n') {
        let mut single_dir_found = false;
        let (key, value) = match split_once(line, b'=') {
            Some(kv) => kv,
            None => continue,
        };

        let key = trim_blank(key);
        let key = if key.starts_with(b"XDG_") && key.ends_with(b"_DIR") {
            match str::from_utf8(&key[4..key.len()-4]) {
                Ok(key) =>
                    if user_dir.is_some() && option_contains(user_dir, key) {
                        single_dir_found = true;
                        key
                    } else if user_dir.is_none() {
                        key
                    } else {
                        continue
                    },
                Err(_)  => continue,
            }
        } else {
            continue
        };

        // xdg-user-dirs-update uses double quotes and we don't support anything else.
        let value = trim_blank(value);
        let mut value = if value.starts_with(b"\"") && value.ends_with(b"\"") {
            &value[1..value.len()-1]
        } else {
            continue
        };

        // Path should be either relative to the home directory or absolute.
        let is_relative = if value == b"$HOME/" {
            // "Note: To disable a directory, point it to the homedir."
            // Source: https://www.freedesktop.org/wiki/Software/xdg-user-dirs/
            // Additionally directory is reassigned to homedir when removed.
            continue
        } else if value.starts_with(b"$HOME/") {
            value = &value[b"$HOME/".len()..];
            true
        } else if value.starts_with(b"/") {
            false
        } else {
            continue
        };

        let value = OsString::from_vec(shell_unescape(value));

        let path = if is_relative {
            let mut path = PathBuf::from(&home_dir);
            path.push(value);
            path
        } else {
            PathBuf::from(value)
        };

        user_dirs.insert(key.to_owned(), path);
        if single_dir_found {
            break;
        }
    }

    user_dirs
}

/// Reads the entire contents of a file into a byte vector.
fn read_all(path: &Path) -> io::Result<Vec<u8>> {
    let mut file = fs::File::open(path)?;
    let mut bytes = Vec::with_capacity(1024);
    file.read_to_end(&mut bytes)?;
    Ok(bytes)
}

/// Returns bytes before and after first occurrence of separator.
fn split_once(bytes: &[u8], separator: u8) -> Option<(&[u8], &[u8])> {
    bytes.iter().position(|b| *b == separator).map(|i| {
        (&bytes[..i], &bytes[i+1..])
    })
}

/// Returns a slice with leading and trailing <blank> characters removed.
fn trim_blank(bytes: &[u8]) -> &[u8] {
    // Trim leading <blank> characters.
    let i = bytes.iter().cloned().take_while(|b| *b == b' ' || *b == b'\t').count();
    let bytes = &bytes[i..];

    // Trim trailing <blank> characters.
    let i = bytes.iter().cloned().rev().take_while(|b| *b == b' ' || *b == b'\t').count();
    &bytes[..bytes.len()-i]
}

/// Unescape bytes escaped with POSIX shell double-quotes rules (as used by xdg-user-dirs-update).
fn shell_unescape(escaped: &[u8]) -> Vec<u8> {
    // We assume that byte string was created by xdg-user-dirs-update which
    // escapes all characters that might potentially have special meaning,
    // so there is no need to check if backslash is actually followed by
    // $ ` " \ or a <newline>.

    let mut unescaped: Vec<u8> = Vec::with_capacity(escaped.len());
    let mut i = escaped.iter().cloned();

    while let Some(b) = i.next() {
        if b == b'\\' {
            if let Some(b) = i.next() {
                unescaped.push(b);
            }
        } else {
            unescaped.push(b);
        }
    }

    unescaped
}

fn option_contains<T : PartialEq>(option: Option<T>, value: T) -> bool {
    match option {
        Some(val) => val == value,
        None => false
    }
}

#[cfg(test)]
mod tests {
    use std::collections::HashMap;
    use std::path::{Path, PathBuf};
    use super::{trim_blank, shell_unescape, split_once, parse_user_dirs};

    #[test]
    fn test_trim_blank() {
        assert_eq!(b"x", trim_blank(b"x"));
        assert_eq!(b"", trim_blank(b" \t  "));
        assert_eq!(b"hello there", trim_blank(b" \t hello there \t "));
        assert_eq!(b"\r\n", trim_blank(b"\r\n"));
    }

    #[test]
    fn test_split_once() {
        assert_eq!(None, split_once(b"a b c", b'='));
        assert_eq!(Some((b"before".as_ref(), b"after".as_ref())), split_once(b"before=after", b'='));
    }

    #[test]
    fn test_shell_unescape() {
        assert_eq!(b"abc", shell_unescape(b"abc").as_slice());
        assert_eq!(b"x\\y$z`", shell_unescape(b"x\\\\y\\$z\\`").as_slice());
    }

    #[test]
    fn test_parse_empty() {
        assert_eq!(HashMap::new(), parse_user_dirs(Path::new("/root/"), None, b""));
        assert_eq!(HashMap::new(), parse_user_dirs(Path::new("/root/"), Some("MUSIC"), b""));
    }

    #[test]
    fn test_absolute_path_is_accepted() {
        let mut dirs = HashMap::new();
        dirs.insert("MUSIC".to_owned(), PathBuf::from("/media/music"));
        let bytes = br#"XDG_MUSIC_DIR="/media/music""#;
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
    }

    #[test]
    fn test_relative_path_is_rejected() {
        let dirs = HashMap::new();
        let bytes = br#"XDG_MUSIC_DIR="music""#;
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
    }

    #[test]
    fn test_relative_to_home() {
        let mut dirs = HashMap::new();
        dirs.insert("MUSIC".to_owned(), PathBuf::from("/home/john/Music"));
        let bytes = br#"XDG_MUSIC_DIR="$HOME/Music""#;
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
    }

    #[test]
    fn test_disabled_directory() {
        let dirs = HashMap::new();
        let bytes = br#"XDG_MUSIC_DIR="$HOME/""#;
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), None, bytes));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/john"), Some("MUSIC"), bytes));
    }

    #[test]
    fn test_parse_user_dirs() {
        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
        dirs.insert("DESKTOP".to_string(), PathBuf::from("/home/bob/Desktop"));
        dirs.insert("DOWNLOAD".to_string(), PathBuf::from("/home/bob/Downloads"));
        dirs.insert("PICTURES".to_string(), PathBuf::from("/home/eve/pics"));

        let bytes = br#"
# This file is written by xdg-user-dirs-update
# If you want to change or add directories, just edit the line you're
# interested in. All local changes will be retained on the next run.
# Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped
# homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an
# absolute path. No other format is supported.
XDG_DESKTOP_DIR="$HOME/Desktop"
XDG_DOWNLOAD_DIR="$HOME/Downloads"
XDG_TEMPLATES_DIR=""
XDG_PUBLICSHARE_DIR="$HOME"
XDG_DOCUMENTS_DIR="$HOME/"
XDG_PICTURES_DIR="/home/eve/pics"
XDG_VIDEOS_DIR="$HOxyzME/Videos"
"#;

        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), None, bytes));

        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
        dirs.insert("DESKTOP".to_string(), PathBuf::from("/home/bob/Desktop"));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("DESKTOP"), bytes));

        let mut dirs: HashMap<String, PathBuf> = HashMap::new();
        dirs.insert("PICTURES".to_string(), PathBuf::from("/home/eve/pics"));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("PICTURES"), bytes));

        let dirs: HashMap<String, PathBuf> = HashMap::new();
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("TEMPLATES"), bytes));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("PUBLICSHARE"), bytes));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("DOCUMENTS"), bytes));
        assert_eq!(dirs, parse_user_dirs(Path::new("/home/bob"), Some("VIDEOS"), bytes));
    }
}