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|
use crate::prelude::*;
use std::convert::TryFrom as _;
use tokio::io::{AsyncRead as _, AsyncWrite as _};
pub struct Frame {
pub time: std::time::Instant,
pub data: Vec<u8>,
}
impl Frame {
fn as_bytes(&self, base: std::time::Instant) -> Vec<u8> {
let dur = self.time - base;
let secs = u32::try_from(dur.as_secs()).unwrap();
let micros = dur.subsec_micros();
let len = u32::try_from(self.data.len()).unwrap();
let mut bytes = vec![];
bytes.extend(secs.to_le_bytes().iter());
bytes.extend(micros.to_le_bytes().iter());
bytes.extend(len.to_le_bytes().iter());
bytes.extend(self.data.iter());
bytes
}
}
pub struct File {
file: tokio::fs::File,
base_time: Option<std::time::Instant>,
waiting: usize,
wframe: futures::sink::Wait<tokio::sync::mpsc::UnboundedSender<Frame>>,
rframe: tokio::sync::mpsc::UnboundedReceiver<Frame>,
writing: std::collections::VecDeque<u8>,
read_buf: [u8; 4096],
reading: std::collections::VecDeque<u8>,
read_state: Option<(u32, u32, u32)>,
read: std::collections::VecDeque<Frame>,
}
impl File {
pub fn new(file: tokio::fs::File) -> Self {
let (wframe, rframe) = tokio::sync::mpsc::unbounded_channel();
Self {
file,
base_time: None,
waiting: 0,
wframe: wframe.wait(),
rframe,
writing: std::collections::VecDeque::new(),
read_buf: [0; 4096],
reading: std::collections::VecDeque::new(),
read_state: None,
read: std::collections::VecDeque::new(),
}
}
pub fn write_frame(&mut self, data: &[u8]) -> Result<()> {
let now = std::time::Instant::now();
if self.base_time.is_none() {
self.base_time = Some(now);
}
self.waiting += 1;
self.wframe
.send(Frame {
time: now,
data: data.to_vec(),
})
.context(crate::error::WriteChannel)
}
pub fn poll_write(
&mut self,
) -> std::result::Result<futures::Async<()>, Error> {
loop {
if self.writing.is_empty() {
match self.rframe.poll().context(crate::error::ReadChannel)? {
futures::Async::Ready(Some(frame)) => {
self.writing.extend(
frame.as_bytes(self.base_time.unwrap()).iter(),
);
self.waiting -= 1;
}
futures::Async::Ready(None) => unreachable!(),
futures::Async::NotReady => {
return Ok(futures::Async::NotReady);
}
}
}
let (a, b) = self.writing.as_slices();
let buf = if a.is_empty() { b } else { a };
match self
.file
.poll_write(buf)
.context(crate::error::WriteFile)?
{
futures::Async::Ready(n) => {
for _ in 0..n {
self.writing.pop_front();
}
}
futures::Async::NotReady => {
return Ok(futures::Async::NotReady);
}
}
}
}
pub fn poll_read(
&mut self,
) -> std::result::Result<futures::Async<Option<Frame>>, Error> {
loop {
if let Some(frame) = self.read.pop_front() {
return Ok(futures::Async::Ready(Some(frame)));
}
match self
.file
.poll_read(&mut self.read_buf)
.context(crate::error::ReadFile)?
{
futures::Async::Ready(n) => {
if n > 0 {
self.reading.extend(self.read_buf[..n].iter());
self.parse_frames();
} else {
return Ok(futures::Async::Ready(None));
}
}
futures::Async::NotReady => {
return Ok(futures::Async::NotReady);
}
}
}
}
pub fn is_empty(&self) -> bool {
self.writing.is_empty() && self.waiting == 0
}
fn parse_frames(&mut self) {
loop {
match self.read_state {
Some((secs, usecs, len)) => {
if self.reading.len() < len as usize {
break;
}
let mut data = vec![];
for _ in 0..len {
data.push(self.reading.pop_front().unwrap());
}
if self.base_time.is_none() {
self.base_time = Some(std::time::Instant::now());
}
let dur = std::time::Duration::from_micros(u64::from(
secs * 1_000_000 + usecs,
));
let time = self.base_time.unwrap() + dur;
self.read.push_back(Frame { time, data });
self.read_state = None;
}
None => {
if self.reading.len() < 12 {
break;
}
let secs1 = self.reading.pop_front().unwrap();
let secs2 = self.reading.pop_front().unwrap();
let secs3 = self.reading.pop_front().unwrap();
let secs4 = self.reading.pop_front().unwrap();
let secs =
u32::from_le_bytes([secs1, secs2, secs3, secs4]);
let usecs1 = self.reading.pop_front().unwrap();
let usecs2 = self.reading.pop_front().unwrap();
let usecs3 = self.reading.pop_front().unwrap();
let usecs4 = self.reading.pop_front().unwrap();
let usecs =
u32::from_le_bytes([usecs1, usecs2, usecs3, usecs4]);
let len1 = self.reading.pop_front().unwrap();
let len2 = self.reading.pop_front().unwrap();
let len3 = self.reading.pop_front().unwrap();
let len4 = self.reading.pop_front().unwrap();
let len = u32::from_le_bytes([len1, len2, len3, len4]);
self.read_state = Some((secs, usecs, len));
}
}
}
}
}
|
