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

#[macro_use] extern crate lazy_static;
extern crate pwd;
extern crate dirs;

use std::{
    io,
    path::{PathBuf, MAIN_SEPARATOR}
};

use pwd::Passwd;

lazy_static! {
static ref PREFIX: String = format!("~{}", MAIN_SEPARATOR);
}

/// Takes a string-like thing and tries to turn it into a PathBuf while expanding `~`'s and `~user`'s
/// into the user's home directory
///
/// # Example
///
/// ```rust
/// extern crate expanduser;
///
/// use expanduser::expanduser;
///
/// # fn main() -> Result<(), ::std::io::Error> {
/// # let old_home = ::std::env::var("HOME").expect("no HOME set");
/// # ::std::env::set_var("HOME", "/home/foo");
/// let path = expanduser("~/path/to/directory")?;
/// # ::std::env::set_var("HOME", &old_home);
/// assert_eq!(path.display().to_string(), "/home/foo/path/to/directory");
/// #   Ok(())
/// # }
/// ```
pub fn expanduser<S: AsRef<str>>(s: S) -> io::Result<PathBuf> {
    Ok(match s.as_ref() {
        // matches paths that start with `~/`
        s if s.starts_with(&*PREFIX) => {
            let home = match dirs::home_dir() {
                Some(home) => home,
                None => return Err(io::Error::new(io::ErrorKind::Other, "no home directory was set")),
            };
            home.join(&s[2..])
        },
        // matches paths that start with `~username/`
        s if s.starts_with("~") => {
            let mut parts = s[1..].splitn(2, MAIN_SEPARATOR);
            let user = match parts.next() {
                Some(user) => user,
                None => return Err(io::Error::new(io::ErrorKind::Other, "malformed path")),
            };
            let path = match parts.next() {
                Some(path) => path,
                None => return Err(io::Error::new(io::ErrorKind::Other, "malformed path")),
            };
            let user = match Passwd::from_name(&user).map_err(|_| io::Error::new(io::ErrorKind::Other, "error searching for user"))? {
                Some(user) => user,
                None => return Err(io::Error::new(io::ErrorKind::Other, "user does not exist")),
            };
            PathBuf::from(user.dir).join(&path)
        },
        s => PathBuf::from(s)
    })
}

#[cfg(test)]
mod tests {
    use std::env;
    use super::*;

    // Until I figure out a better to way to test this stuff in isolation, it is necessary to run
    // this using `cargo test -- --test-threads 1`, otherwise you will probably get race conditions
    // from the HOME manipulation

    #[test]
    fn test_success() {
        let old_home = env::var("HOME").expect("no home dir set");
        let new_home = "/home/foo";
        env::set_var("HOME", new_home);
        let path = expanduser("~/path/to/directory");
        env::set_var("HOME", old_home);
        assert_eq!(path.expect("io error"), PathBuf::from("/home/foo/path/to/directory"));
    }

    #[test]
    fn test_user() {
        let user = env::var("USER").expect("no user set");
        if user.len() < 1 {
            panic!("user is empty");
        }
        let home = dirs::home_dir().expect("no home directory set");
        let pathstr = format!("~{}/path/to/directory", &user);
        let path = expanduser(&pathstr).expect("io error");
        assert_eq!(path, home.join("path/to/directory"));
    }

    #[test]
    #[should_panic]
    fn test_user_does_not_exist() {
        expanduser("~user_that_should_not_exist/path/to/directory")
                        .expect("user does not exist");
    }
}