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use core::fmt::{self, Display, Debug};
use Fail;
without_std! {
pub struct Context<D: Display + Send + Sync + 'static> {
context: D,
}
impl<D: Display + Send + Sync + 'static> Context<D> {
pub fn new(context: D) -> Context<D> {
Context { context }
}
pub fn get_context(&self) -> &D {
&self.context
}
pub(crate) fn with_err<E: Fail>(context: D, _: E) -> Context<D> {
Context { context }
}
}
impl<D: Display + Send + Sync + 'static> Fail for Context<D> { }
impl<D: Display + Send + Sync + 'static> Debug for Context<D> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.context)
}
}
impl<D: Display + Send + Sync + 'static> Display for Context<D> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.context)
}
}
}
with_std! {
use {Error, Backtrace};
pub struct Context<D: Display + Send + Sync + 'static> {
context: D,
failure: Either<Backtrace, Error>,
}
impl<D: Display + Send + Sync + 'static> Context<D> {
pub fn new(context: D) -> Context<D> {
let failure = Either::This(Backtrace::new());
Context { context, failure }
}
pub fn get_context(&self) -> &D {
&self.context
}
pub(crate) fn with_err<E: Into<Error>>(context: D, error: E) -> Context<D> {
let failure = Either::That(error.into());
Context { context, failure }
}
}
impl<D: Display + Send + Sync + 'static> Fail for Context<D> {
fn cause(&self) -> Option<&Fail> {
self.failure.cause()
}
fn backtrace(&self) -> Option<&Backtrace> {
Some(self.failure.backtrace())
}
}
impl<D: Display + Send + Sync + 'static> Debug for Context<D> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:?}\n\n{}", self.failure, self.context)
}
}
impl<D: Display + Send + Sync + 'static> Display for Context<D> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.context)
}
}
enum Either<A, B> {
This(A),
That(B),
}
impl Either<Backtrace, Error> {
fn backtrace(&self) -> &Backtrace {
match *self {
Either::This(ref backtrace) => backtrace,
Either::That(ref error) => error.backtrace(),
}
}
fn cause(&self) -> Option<&Fail> {
match *self {
Either::This(_) => None,
Either::That(ref error) => Some(error.cause())
}
}
}
impl Debug for Either<Backtrace, Error> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match *self {
Either::This(ref backtrace) => write!(f, "{:?}", backtrace),
Either::That(ref error) => write!(f, "{:?}", error),
}
}
}
}
impl<D> From<D> for Context<D> where
D: Display + Send + Sync + 'static
{
fn from(display: D) -> Context<D> {
Context::new(display)
}
}