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use bytes::{Buf, BufMut, IntoBuf};
use frame::{Error, Frame, Head, Kind, StreamId};
const ACK_FLAG: u8 = 0x1;
pub type Payload = [u8; 8];
#[derive(Debug, Eq, PartialEq)]
pub struct Ping {
ack: bool,
payload: Payload,
}
// This was just 8 randomly generated bytes. We use something besides just
// zeroes to distinguish this specific PING from any other.
const SHUTDOWN_PAYLOAD: Payload = [0x0b, 0x7b, 0xa2, 0xf0, 0x8b, 0x9b, 0xfe, 0x54];
impl Ping {
#[cfg(feature = "unstable")]
pub const SHUTDOWN: Payload = SHUTDOWN_PAYLOAD;
#[cfg(not(feature = "unstable"))]
pub(crate) const SHUTDOWN: Payload = SHUTDOWN_PAYLOAD;
pub fn new(payload: Payload) -> Ping {
Ping {
ack: false,
payload,
}
}
pub fn pong(payload: Payload) -> Ping {
Ping {
ack: true,
payload,
}
}
pub fn is_ack(&self) -> bool {
self.ack
}
pub fn payload(&self) -> &Payload {
&self.payload
}
pub fn into_payload(self) -> Payload {
self.payload
}
/// Builds a `Ping` frame from a raw frame.
pub fn load(head: Head, bytes: &[u8]) -> Result<Ping, Error> {
debug_assert_eq!(head.kind(), ::frame::Kind::Ping);
// PING frames are not associated with any individual stream. If a PING
// frame is received with a stream identifier field value other than
// 0x0, the recipient MUST respond with a connection error
// (Section 5.4.1) of type PROTOCOL_ERROR.
if !head.stream_id().is_zero() {
return Err(Error::InvalidStreamId);
}
// In addition to the frame header, PING frames MUST contain 8 octets of opaque
// data in the payload.
if bytes.len() != 8 {
return Err(Error::BadFrameSize);
}
let mut payload = [0; 8];
bytes.into_buf().copy_to_slice(&mut payload);
// The PING frame defines the following flags:
//
// ACK (0x1): When set, bit 0 indicates that this PING frame is a PING
// response. An endpoint MUST set this flag in PING responses. An
// endpoint MUST NOT respond to PING frames containing this flag.
let ack = head.flag() & ACK_FLAG != 0;
Ok(Ping {
ack,
payload,
})
}
pub fn encode<B: BufMut>(&self, dst: &mut B) {
let sz = self.payload.len();
trace!("encoding PING; ack={} len={}", self.ack, sz);
let flags = if self.ack { ACK_FLAG } else { 0 };
let head = Head::new(Kind::Ping, flags, StreamId::zero());
head.encode(sz, dst);
dst.put_slice(&self.payload);
}
}
impl<T> From<Ping> for Frame<T> {
fn from(src: Ping) -> Frame<T> {
Frame::Ping(src)
}
}