1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
#![doc(html_root_url = "https://docs.rs/http-body/0.4.1")]
#![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 next;
mod size_hint;

pub mod combinators;

pub use self::empty::Empty;
pub use self::next::{Data, Trailers};
pub use self::size_hint::SizeHint;

use self::combinators::{BoxBody, MapData, MapErr};
use bytes::Buf;
use http::HeaderMap;
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)
    }
}

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()
    }
}

#[cfg(test)]
fn _assert_bounds() {
    fn can_be_trait_object(_: &dyn Body<Data = std::io::Cursor<Vec<u8>>, Error = std::io::Error>) {}
}