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use crate::frame::{self, Error, Head, Kind, StreamId};
use bytes::BufMut;
const SIZE_INCREMENT_MASK: u32 = 1 << 31;
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub struct WindowUpdate {
stream_id: StreamId,
size_increment: u32,
}
impl WindowUpdate {
pub fn new(stream_id: StreamId, size_increment: u32) -> WindowUpdate {
WindowUpdate {
stream_id,
size_increment,
}
}
pub fn stream_id(&self) -> StreamId {
self.stream_id
}
pub fn size_increment(&self) -> u32 {
self.size_increment
}
/// Builds a `WindowUpdate` frame from a raw frame.
pub fn load(head: Head, payload: &[u8]) -> Result<WindowUpdate, Error> {
debug_assert_eq!(head.kind(), crate::frame::Kind::WindowUpdate);
if payload.len() != 4 {
return Err(Error::BadFrameSize);
}
// Clear the most significant bit, as that is reserved and MUST be ignored
// when received.
let size_increment = unpack_octets_4!(payload, 0, u32) & !SIZE_INCREMENT_MASK;
if size_increment == 0 {
return Err(Error::InvalidWindowUpdateValue);
}
Ok(WindowUpdate {
stream_id: head.stream_id(),
size_increment,
})
}
pub fn encode<B: BufMut>(&self, dst: &mut B) {
tracing::trace!("encoding WINDOW_UPDATE; id={:?}", self.stream_id);
let head = Head::new(Kind::WindowUpdate, 0, self.stream_id);
head.encode(4, dst);
dst.put_u32(self.size_increment);
}
}
impl<B> From<WindowUpdate> for frame::Frame<B> {
fn from(src: WindowUpdate) -> Self {
frame::Frame::WindowUpdate(src)
}
}