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use std::error::Error;
use std::ffi::{OsStr, OsString};
use std::fmt;
use std::env;
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum VarError {
NotPresent(String),
NotUnicode(OsString),
}
impl fmt::Display for VarError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
VarError::NotPresent(ref s) => write!(f, "environment variable \"{}\" not found", s),
VarError::NotUnicode(ref s) => {
write!(f, "environment variable was not valid unicode: {:?}", s)
}
}
}
}
impl Error for VarError {
fn description(&self) -> &str {
match *self {
VarError::NotPresent(..) => "environment variable not found",
VarError::NotUnicode(..) => "environment variable was not valid unicode",
}
}
}
pub fn var<K:AsRef<OsStr>>(key: K) -> Result<String, VarError> {
match env::var_os(&key) {
Some(s) => s.into_string().map_err(VarError::NotUnicode),
None => Err(VarError::NotPresent(key.as_ref().to_str().unwrap().to_owned())),
}
}