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#![deny(
missing_debug_implementations,
missing_docs,
unreachable_pub,
broken_intra_doc_links
)]
#![cfg_attr(test, deny(warnings))]
//! Asynchronous HTTP request or response body.
//!
//! See [`Body`] for more details.
//!
//! [`Body`]: trait.Body.html
mod empty;
mod full;
mod limited;
mod next;
mod size_hint;
pub mod combinators;
pub use self::empty::Empty;
pub use self::full::Full;
pub use self::limited::{LengthLimitError, Limited};
pub use self::next::{Data, Trailers};
pub use self::size_hint::SizeHint;
use self::combinators::{BoxBody, MapData, MapErr, UnsyncBoxBody};
use bytes::{Buf, Bytes};
use http::HeaderMap;
use std::convert::Infallible;
use std::ops;
use std::pin::Pin;
use std::task::{Context, Poll};
/// Trait representing a streaming body of a Request or Response.
///
/// Data is streamed via the `poll_data` function, which asynchronously yields `T: Buf` values. The
/// `size_hint` function provides insight into the total number of bytes that will be streamed.
///
/// The `poll_trailers` function returns an optional set of trailers used to finalize the request /
/// response exchange. This is mostly used when using the HTTP/2.0 protocol.
///
pub trait Body {
/// Values yielded by the `Body`.
type Data: Buf;
/// The error type this `Body` might generate.
type Error;
/// Attempt to pull out the next data buffer of this stream.
fn poll_data(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>>;
/// Poll for an optional **single** `HeaderMap` of trailers.
///
/// This function should only be called once `poll_data` returns `None`.
fn poll_trailers(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>>;
/// Returns `true` when the end of stream has been reached.
///
/// An end of stream means that both `poll_data` and `poll_trailers` will
/// return `None`.
///
/// A return value of `false` **does not** guarantee that a value will be
/// returned from `poll_stream` or `poll_trailers`.
fn is_end_stream(&self) -> bool {
false
}
/// Returns the bounds on the remaining length of the stream.
///
/// When the **exact** remaining length of the stream is known, the upper bound will be set and
/// will equal the lower bound.
fn size_hint(&self) -> SizeHint {
SizeHint::default()
}
/// Returns future that resolves to next data chunk, if any.
fn data(&mut self) -> Data<'_, Self>
where
Self: Unpin + Sized,
{
Data(self)
}
/// Returns future that resolves to trailers, if any.
fn trailers(&mut self) -> Trailers<'_, Self>
where
Self: Unpin + Sized,
{
Trailers(self)
}
/// Maps this body's data value to a different value.
fn map_data<F, B>(self, f: F) -> MapData<Self, F>
where
Self: Sized,
F: FnMut(Self::Data) -> B,
B: Buf,
{
MapData::new(self, f)
}
/// Maps this body's error value to a different value.
fn map_err<F, E>(self, f: F) -> MapErr<Self, F>
where
Self: Sized,
F: FnMut(Self::Error) -> E,
{
MapErr::new(self, f)
}
/// Turn this body into a boxed trait object.
fn boxed(self) -> BoxBody<Self::Data, Self::Error>
where
Self: Sized + Send + Sync + 'static,
{
BoxBody::new(self)
}
/// Turn this body into a boxed trait object that is !Sync.
fn boxed_unsync(self) -> UnsyncBoxBody<Self::Data, Self::Error>
where
Self: Sized + Send + 'static,
{
UnsyncBoxBody::new(self)
}
}
impl<T: Body + Unpin + ?Sized> Body for &mut T {
type Data = T::Data;
type Error = T::Error;
fn poll_data(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
Pin::new(&mut **self).poll_data(cx)
}
fn poll_trailers(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
Pin::new(&mut **self).poll_trailers(cx)
}
fn is_end_stream(&self) -> bool {
Pin::new(&**self).is_end_stream()
}
fn size_hint(&self) -> SizeHint {
Pin::new(&**self).size_hint()
}
}
impl<P> Body for Pin<P>
where
P: Unpin + ops::DerefMut,
P::Target: Body,
{
type Data = <<P as ops::Deref>::Target as Body>::Data;
type Error = <<P as ops::Deref>::Target as Body>::Error;
fn poll_data(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
Pin::get_mut(self).as_mut().poll_data(cx)
}
fn poll_trailers(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
Pin::get_mut(self).as_mut().poll_trailers(cx)
}
fn is_end_stream(&self) -> bool {
self.as_ref().is_end_stream()
}
fn size_hint(&self) -> SizeHint {
self.as_ref().size_hint()
}
}
impl<T: Body + Unpin + ?Sized> Body for Box<T> {
type Data = T::Data;
type Error = T::Error;
fn poll_data(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
Pin::new(&mut **self).poll_data(cx)
}
fn poll_trailers(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
Pin::new(&mut **self).poll_trailers(cx)
}
fn is_end_stream(&self) -> bool {
self.as_ref().is_end_stream()
}
fn size_hint(&self) -> SizeHint {
self.as_ref().size_hint()
}
}
impl<B: Body> Body for http::Request<B> {
type Data = B::Data;
type Error = B::Error;
fn poll_data(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
unsafe {
self.map_unchecked_mut(http::Request::body_mut)
.poll_data(cx)
}
}
fn poll_trailers(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
unsafe {
self.map_unchecked_mut(http::Request::body_mut)
.poll_trailers(cx)
}
}
fn is_end_stream(&self) -> bool {
self.body().is_end_stream()
}
fn size_hint(&self) -> SizeHint {
self.body().size_hint()
}
}
impl<B: Body> Body for http::Response<B> {
type Data = B::Data;
type Error = B::Error;
fn poll_data(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
unsafe {
self.map_unchecked_mut(http::Response::body_mut)
.poll_data(cx)
}
}
fn poll_trailers(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<Result<Option<HeaderMap>, Self::Error>> {
unsafe {
self.map_unchecked_mut(http::Response::body_mut)
.poll_trailers(cx)
}
}
fn is_end_stream(&self) -> bool {
self.body().is_end_stream()
}
fn size_hint(&self) -> SizeHint {
self.body().size_hint()
}
}
impl Body for String {
type Data = Bytes;
type Error = Infallible;
fn poll_data(
mut self: Pin<&mut Self>,
_cx: &mut Context<'_>,
) -> Poll<Option<Result<Self::Data, Self::Error>>> {
if !self.is_empty() {
let s = std::mem::take(&mut *self);
Poll::Ready(Some(Ok(s.into_bytes().into())))
} else {
Poll::Ready(None)
}
}
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 {
self.is_empty()
}
fn size_hint(&self) -> SizeHint {
SizeHint::with_exact(self.len() as u64)
}
}
#[cfg(test)]
fn _assert_bounds() {
fn can_be_trait_object(_: &dyn Body<Data = std::io::Cursor<Vec<u8>>, Error = std::io::Error>) {}
}