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use crate::message::{EncodeError, Encoder, Frame}; use crate::noise::{Cipher, HandshakeResult}; use futures_lite::{ready, AsyncWrite}; use std::collections::VecDeque; use std::fmt; use std::io::Result; use std::pin::Pin; use std::task::{Context, Poll}; const BUF_SIZE: usize = 1024 * 64; #[derive(Debug)] pub enum Step { Flushing, Writing, Processing, } pub struct WriteState { queue: VecDeque<Frame>, buf: Vec<u8>, current_frame: Option<Frame>, start: usize, end: usize, cipher: Option<Cipher>, step: Step, } impl fmt::Debug for WriteState { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct("WriteState") .field("queue (len)", &self.queue.len()) .field("step", &self.step) .field("buf (len)", &self.buf.len()) .field("current_frame", &self.current_frame) .field("start", &self.start) .field("end", &self.end) .field("cipher", &self.cipher.is_some()) .finish() } } impl WriteState { pub fn new() -> Self { Self { queue: VecDeque::new(), buf: vec![0u8; BUF_SIZE], current_frame: None, start: 0, end: 0, cipher: None, step: Step::Processing, } } pub fn queue_frame<F>(&mut self, frame: F) where F: Into<Frame>, { self.queue.push_back(frame.into()) } pub fn try_queue_direct<T: Encoder>( &mut self, frame: &T, ) -> std::result::Result<bool, EncodeError> { let len = frame.encoded_len(); if self.buf.len() < len { self.buf.resize(len, 0u8); } if len > self.remaining() { return Ok(false); } let len = frame.encode(&mut self.buf[self.end..])?; self.advance(len); Ok(true) } pub fn can_park_frame(&self) -> bool { self.current_frame.is_none() } pub fn park_frame<F>(&mut self, frame: F) where F: Into<Frame>, { if self.current_frame.is_none() { self.current_frame = Some(frame.into()) } } fn advance(&mut self, n: usize) { let end = self.end + n; if let Some(ref mut cipher) = self.cipher { cipher.apply(&mut self.buf[self.end..end]); } self.end = end; } pub fn upgrade_with_handshake(&mut self, handshake: &HandshakeResult) -> Result<()> { let cipher = Cipher::from_handshake_tx(handshake)?; self.cipher = Some(cipher); Ok(()) } fn remaining(&self) -> usize { self.buf.len() - self.end } fn pending(&self) -> usize { self.end - self.start } pub fn poll_send<W>(&mut self, cx: &mut Context<'_>, mut writer: &mut W) -> Poll<Result<()>> where W: AsyncWrite + Unpin, { loop { self.step = match self.step { Step::Processing => { if self.current_frame.is_none() && !self.queue.is_empty() { self.current_frame = self.queue.pop_front(); } if let Some(frame) = self.current_frame.take() { if !self.try_queue_direct(&frame)? { self.current_frame = Some(frame); } } if self.pending() == 0 { return Poll::Ready(Ok(())); } Step::Writing } Step::Writing => { let n = ready!( Pin::new(&mut writer).poll_write(cx, &self.buf[self.start..self.end]) )?; self.start += n; if self.start == self.end { self.start = 0; self.end = 0; } Step::Flushing } Step::Flushing => { ready!(Pin::new(&mut writer).poll_flush(cx))?; Step::Processing } } } } }