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use std::error::Error as StdError;
use std::fmt;
/// The different types of errors that can occur while manipulating control groups.
#[derive(Debug, Eq, PartialEq)]
pub enum ErrorKind {
/// An error occured while writing to a control group file.
WriteFailed,
/// An error occured while trying to read from a control group file.
ReadFailed,
/// An error occured while trying to parse a value from a control group file.
///
/// In the future, there will be some information attached to this field.
ParseError,
/// You tried to do something invalid.
///
/// This could be because you tried to set a value in a control group that is not a root
/// control group. Or, when using unified hierarchy, you tried to add a task in a leaf node.
InvalidOperation,
/// The path of the control group was invalid.
///
/// This could be caused by trying to escape the control group filesystem via a string of "..".
/// This crate checks against this and operations will fail with this error.
InvalidPath,
/// An unknown error has occured.
Other,
}
#[derive(Debug)]
pub struct Error {
kind: ErrorKind,
cause: Option<Box<StdError + Send>>,
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let msg = match self.kind {
ErrorKind::WriteFailed => "unable to write to a control group file",
ErrorKind::ReadFailed => "unable to read a control group file",
ErrorKind::ParseError => "unable to parse control group file",
ErrorKind::InvalidOperation => "the requested operation is invalid",
ErrorKind::InvalidPath => "the given path is invalid",
ErrorKind::Other => "an unknown error",
};
write!(f, "{}", msg)
}
}
impl StdError for Error {
fn cause(&self) -> Option<&StdError> {
match self.cause {
Some(ref x) => Some(&**x),
None => None,
}
}
}
impl Error {
pub(crate) fn new(kind: ErrorKind) -> Self {
Self {
kind,
cause: None,
}
}
pub(crate) fn with_cause<E>(kind: ErrorKind, cause: E) -> Self
where
E: 'static + Send + StdError,
{
Self {
kind,
cause: Some(Box::new(cause)),
}
}
pub fn kind(&self) -> &ErrorKind {
&self.kind
}
}
pub type Result<T> = ::std::result::Result<T, Error>;