Betriebssysteme/hw6/task2/src/command.rs

use std::ffi::OsString;
use std::str::FromStr;
use std::env;

pub enum Command {
    Empty,
    Exit,
    Cd(Option<OsString>),
}

pub struct CommandNotFoundError;

impl FromStr for Command {
    type Err = CommandNotFoundError;
    fn from_str(s: &str) -> Result<Self, Self::Err> {

        let mut parts = s.split_whitespace();

        match parts.next() {
            Some("exit") => {
                Ok(Command::Exit)
            },
            Some("cd") => {
                Ok(Command::parse_cd(parts.next()))
            },
            Some(cmd) => {
                //For use in next homework, to execute programs.
                let _ = cmd;
                Err(CommandNotFoundError)
            },
            None => {
                Ok(Command::Empty)
            },
        }
    }

}


impl Command {

    /// If the passed String exists, set the path of the Cd in the enum
    pub fn parse_cd(cmd: Option<&str>) -> Self {
        match cmd {
            None => Command::Cd(None),
            Some(dest) => Command::Cd(Some(OsString::from(dest))),
        }
    }

    pub fn exec_cd(&self) {
        if let Command::Cd(None) = *self  {
            let possible_home = env::home_dir();

            if let Some(home) = possible_home {
                let home_path = home.as_path();
                let _ = env::set_current_dir(home_path);
            }

        }

        if let Command::Cd(Some(ref path)) = *self {
            match path.to_str() {
                Some(_) => {
                    let _ = env::set_current_dir(path);
                },
                None => {},
            }

        }
    }
}