use std::fmt;
use std::error;
pub enum Error<E> {
Permanent(E),
Transient(E),
}
impl<E> fmt::Display for Error<E>
where E: fmt::Display
{
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match *self {
Error::Permanent(ref err) |
Error::Transient(ref err) => err.fmt(f),
}
}
}
impl<E> fmt::Debug for Error<E>
where E: fmt::Debug
{
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
let (name, err) = match *self {
Error::Permanent(ref err) => ("Permanent", err as &dyn fmt::Debug),
Error::Transient(ref err) => ("Transient", err as &dyn fmt::Debug),
};
f.debug_tuple(name).field(err).finish()
}
}
impl<E> error::Error for Error<E>
where E: error::Error
{
fn description(&self) -> &str {
match *self {
Error::Permanent(_) => "permanent error",
Error::Transient(_) => "transient error",
}
}
fn source(&self) -> Option<&(dyn error::Error + 'static)> {
match *self {
Error::Permanent(ref err) |
Error::Transient(ref err) => err.source(),
}
}
fn cause(&self) -> Option<&dyn error::Error> {
self.source()
}
}
impl<E> From<E> for Error<E> {
fn from(err: E) -> Error<E> {
Error::Transient(err)
}
}