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use std;
use std::ffi::NulError;
use std::fmt::{self, Formatter};
use std::sync::{mpsc, Arc};
use try_from::TryFromIntError;
pub type Result<T> = std::result::Result<T, Error>;
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum ErrorKind {
BadTypeCast,
ConnectionFailed,
EncodingError,
FormatError,
IncompatibleResource,
InvalidArgument,
InvalidOperation,
LibraryError,
LockedDisplay,
NoMatch,
RequestFailed,
ResourceExpired,
SynchronizationError,
Unimplemented,
Unsupported,
}
impl ErrorKind {
pub fn description (self) -> &'static str {
match self {
ErrorKind::BadTypeCast => "bad type cast",
ErrorKind::ConnectionFailed => "connection failed",
ErrorKind::EncodingError => "encoding error",
ErrorKind::FormatError => "format error",
ErrorKind::IncompatibleResource => "incompatible resource",
ErrorKind::InvalidArgument => "invalid argument",
ErrorKind::InvalidOperation => "invalid operation",
ErrorKind::LibraryError => "library error",
ErrorKind::LockedDisplay => "locked display",
ErrorKind::NoMatch => "no match",
ErrorKind::RequestFailed => "request failed",
ErrorKind::ResourceExpired => "resource expired",
ErrorKind::SynchronizationError => "synchronization error",
ErrorKind::Unimplemented => "unimplemented",
ErrorKind::Unsupported => "unsupported",
}
}
}
#[derive(Clone, Debug)]
enum Detail {
Static(&'static str),
Owned(String),
}
impl AsRef<str> for Detail {
fn as_ref (&self) -> &str {
match *self {
Detail::Static(s) => s,
Detail::Owned(ref s) => s.as_str(),
}
}
}
#[derive(Clone, Debug)]
pub struct Error {
kind: ErrorKind,
detail: Option<Detail>,
cause: Option<Arc<std::error::Error + Send + Sync>>,
}
impl Error {
pub fn new (kind: ErrorKind) -> Error {
Error {
kind: kind,
detail: None,
cause: None,
}
}
pub fn with_cause<E> (mut self, cause: E) -> Error
where E: std::error::Error + Send + Sync + 'static
{
self.cause = Some(Arc::new(cause));
self
}
pub fn with_detail<T> (mut self, detail: T) -> Error
where T: std::fmt::Display
{
self.detail = Some(Detail::Owned(detail.to_string()));
self
}
pub fn with_str (mut self, detail: &'static str) -> Error {
self.detail = Some(Detail::Static(detail));
self
}
}
impl fmt::Display for Error {
fn fmt (&self, f: &mut Formatter) -> fmt::Result {
f.write_str(self.kind.description())?;
if let Some(ref detail) = self.detail {
f.write_str(" (")?;
f.write_str(detail.as_ref())?;
f.write_str(")")?;
}
if let Some(ref cause) = self.cause {
f.write_str(": ")?;
fmt::Display::fmt(cause, f)?;
}
Ok(())
}
}
impl std::error::Error for Error {
fn cause (&self) -> Option<&std::error::Error> {
self.cause.as_ref().map(|e| &**e as &std::error::Error)
}
fn description (&self) -> &str { self.kind.description() }
}
macro_rules! err {
($kind:ident) => {
$crate::error::Error::new($crate::error::ErrorKind::$kind)
};
}
impl From<NulError> for Error {
fn from (err: NulError) -> Error { err!(EncodingError).with_cause(err) }
}
impl From<TryFromIntError> for Error {
fn from (err: TryFromIntError) -> Error { err!(BadTypeCast).with_cause(err) }
}
impl<T> From<mpsc::SendError<T>> for Error {
fn from (err: mpsc::SendError<T>) -> Error { err!(SynchronizationError).with_detail(err) }
}