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use super::{Body, SizeHint};
use bytes::Buf;
use http::HeaderMap;
use std::{
convert::Infallible,
fmt,
marker::PhantomData,
pin::Pin,
task::{Context, Poll},
};
/// A body that is always empty.
pub struct Empty<D> {
_marker: PhantomData<fn() -> D>,
}
impl<D> Empty<D> {
/// Create a new `Empty`.
pub fn new() -> Self {
Self::default()
}
}
impl<D: Buf> Body for Empty<D> {
type Data = D;
type Error = Infallible;
#[inline]
fn poll_data(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
Poll::Ready(None)
}
#[inline]
fn poll_trailers(
self: Pin<&mut Self>,
_cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
Poll::Ready(Ok(None))
}
fn is_end_stream(&self) -> bool {
true
}
fn size_hint(&self) -> SizeHint {
SizeHint::with_exact(0)
}
}
impl<D> fmt::Debug for Empty<D> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Empty").finish()
}
}
impl<D> Default for Empty<D> {
fn default() -> Self {
Self {
_marker: PhantomData,
}
}
}
impl<D> Clone for Empty<D> {
fn clone(&self) -> Self {
Self {
_marker: PhantomData,
}
}
}
impl<D> Copy for Empty<D> {}