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//! An asynchronous, HTTP/2.0 server and client implementation.
//!
//! This library implements the [HTTP/2.0] specification. The implementation is
//! asynchronous, using [futures] as the basis for the API. The implementation
//! is also decoupled from TCP or TLS details. The user must handle ALPN and
//! HTTP/1.1 upgrades themselves.
//!
//! # Getting started
//!
//! Add the following to your `Cargo.toml` file:
//!
//! ```toml
//! [dependencies]
//! h2 = "0.3"
//! ```
//!
//! # Layout
//!
//! The crate is split into [`client`] and [`server`] modules. Types that are
//! common to both clients and servers are located at the root of the crate.
//!
//! See module level documentation for more details on how to use `h2`.
//!
//! # Handshake
//!
//! Both the client and the server require a connection to already be in a state
//! ready to start the HTTP/2.0 handshake. This library does not provide
//! facilities to do this.
//!
//! There are three ways to reach an appropriate state to start the HTTP/2.0
//! handshake.
//!
//! * Opening an HTTP/1.1 connection and performing an [upgrade].
//! * Opening a connection with TLS and use ALPN to negotiate the protocol.
//! * Open a connection with prior knowledge, i.e. both the client and the
//! server assume that the connection is immediately ready to start the
//! HTTP/2.0 handshake once opened.
//!
//! Once the connection is ready to start the HTTP/2.0 handshake, it can be
//! passed to [`server::handshake`] or [`client::handshake`]. At this point, the
//! library will start the handshake process, which consists of:
//!
//! * The client sends the connection preface (a predefined sequence of 24
//! octets).
//! * Both the client and the server sending a SETTINGS frame.
//!
//! See the [Starting HTTP/2] in the specification for more details.
//!
//! # Flow control
//!
//! [Flow control] is a fundamental feature of HTTP/2.0. The `h2` library
//! exposes flow control to the user.
//!
//! An HTTP/2.0 client or server may not send unlimited data to the peer. When a
//! stream is initiated, both the client and the server are provided with an
//! initial window size for that stream. A window size is the number of bytes
//! the endpoint can send to the peer. At any point in time, the peer may
//! increase this window size by sending a `WINDOW_UPDATE` frame. Once a client
//! or server has sent data filling the window for a stream, no further data may
//! be sent on that stream until the peer increases the window.
//!
//! There is also a **connection level** window governing data sent across all
//! streams.
//!
//! Managing flow control for inbound data is done through [`FlowControl`].
//! Managing flow control for outbound data is done through [`SendStream`]. See
//! the struct level documentation for those two types for more details.
//!
//! [HTTP/2.0]: https://http2.github.io/
//! [futures]: https://docs.rs/futures/
//! [`client`]: client/index.html
//! [`server`]: server/index.html
//! [Flow control]: http://httpwg.org/specs/rfc7540.html#FlowControl
//! [`FlowControl`]: struct.FlowControl.html
//! [`SendStream`]: struct.SendStream.html
//! [Starting HTTP/2]: http://httpwg.org/specs/rfc7540.html#starting
//! [upgrade]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Protocol_upgrade_mechanism
//! [`server::handshake`]: server/fn.handshake.html
//! [`client::handshake`]: client/fn.handshake.html
#![doc(html_root_url = "https://docs.rs/h2/0.3.6")]
#![deny(missing_debug_implementations, missing_docs)]
#![cfg_attr(test, deny(warnings))]
macro_rules! proto_err {
(conn: $($msg:tt)+) => {
tracing::debug!("connection error PROTOCOL_ERROR -- {};", format_args!($($msg)+))
};
(stream: $($msg:tt)+) => {
tracing::debug!("stream error PROTOCOL_ERROR -- {};", format_args!($($msg)+))
};
}
macro_rules! ready {
($e:expr) => {
match $e {
::std::task::Poll::Ready(r) => r,
::std::task::Poll::Pending => return ::std::task::Poll::Pending,
}
};
}
#[cfg_attr(feature = "unstable", allow(missing_docs))]
mod codec;
mod error;
mod hpack;
#[cfg(not(feature = "unstable"))]
mod proto;
#[cfg(feature = "unstable")]
#[allow(missing_docs)]
pub mod proto;
#[cfg(not(feature = "unstable"))]
mod frame;
#[cfg(feature = "unstable")]
#[allow(missing_docs)]
pub mod frame;
pub mod client;
pub mod server;
mod share;
#[cfg(fuzzing)]
#[cfg_attr(feature = "unstable", allow(missing_docs))]
pub mod fuzz_bridge;
pub use crate::error::{Error, Reason};
pub use crate::share::{FlowControl, Ping, PingPong, Pong, RecvStream, SendStream, StreamId};
#[cfg(feature = "unstable")]
pub use codec::{Codec, SendError, UserError};
use std::task::Poll;
// TODO: Get rid of this trait once https://github.com/rust-lang/rust/pull/63512
// is stabilized.
trait PollExt<T, E> {
/// Changes the success value of this `Poll` with the closure provided.
fn map_ok_<U, F>(self, f: F) -> Poll<Option<Result<U, E>>>
where
F: FnOnce(T) -> U;
/// Changes the error value of this `Poll` with the closure provided.
fn map_err_<U, F>(self, f: F) -> Poll<Option<Result<T, U>>>
where
F: FnOnce(E) -> U;
}
impl<T, E> PollExt<T, E> for Poll<Option<Result<T, E>>> {
fn map_ok_<U, F>(self, f: F) -> Poll<Option<Result<U, E>>>
where
F: FnOnce(T) -> U,
{
match self {
Poll::Ready(Some(Ok(t))) => Poll::Ready(Some(Ok(f(t)))),
Poll::Ready(Some(Err(e))) => Poll::Ready(Some(Err(e))),
Poll::Ready(None) => Poll::Ready(None),
Poll::Pending => Poll::Pending,
}
}
fn map_err_<U, F>(self, f: F) -> Poll<Option<Result<T, U>>>
where
F: FnOnce(E) -> U,
{
match self {
Poll::Ready(Some(Ok(t))) => Poll::Ready(Some(Ok(t))),
Poll::Ready(Some(Err(e))) => Poll::Ready(Some(Err(f(e)))),
Poll::Ready(None) => Poll::Ready(None),
Poll::Pending => Poll::Pending,
}
}
}