85 lines
2.3 KiB
Rust
85 lines
2.3 KiB
Rust
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use anyhow::{bail, Result};
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use tokio::io::{AsyncRead, AsyncReadExt as _};
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#[derive(Clone, Copy, Debug, PartialEq, Eq)]
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pub enum RequestKind {
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Signal,
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Command,
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}
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#[derive(Debug)]
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pub struct Request<'a> {
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pub kind: RequestKind,
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body: &'a str,
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}
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impl<'a> Request<'a> {
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pub async fn read<R: AsyncRead + Unpin>(
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reader: &mut R,
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buffer: &'a mut Vec<u8>,
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) -> Result<Self> {
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buffer.clear();
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let mut char = reader.read_u8().await?;
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while char == b'+' {
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// just ignore positive acks
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char = reader.read_u8().await?;
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}
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if char == b'-' {
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bail!("no support for negative acks");
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}
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if char == 0x03 {
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// This is how the client "cancels an in-flight request"
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buffer.push(char);
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let body = std::str::from_utf8(buffer)?;
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return Ok(Self {
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kind: RequestKind::Signal,
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body,
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});
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}
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if char != b'$' {
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// Messages are supposed to start with a dollar sign
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bail!("malformed message");
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}
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// now read the body
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let mut checksum = 0u8;
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char = reader.read_u8().await?;
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while char != b'#' {
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if char == b'}' {
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// escape character
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checksum = checksum.wrapping_add(char);
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char = reader.read_u8().await?;
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checksum = checksum.wrapping_add(char);
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buffer.push(char ^ 0x20);
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} else {
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checksum = checksum.wrapping_add(char);
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buffer.push(char);
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}
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char = reader.read_u8().await?;
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}
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let mut checksum_bytes = [b'0'; 2];
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reader.read_exact(&mut checksum_bytes).await?;
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let checksum_str = std::str::from_utf8(&checksum_bytes)?;
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let real_checksum = u8::from_str_radix(checksum_str, 16)?;
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if checksum != real_checksum {
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bail!("invalid checksum");
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}
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let body = std::str::from_utf8(buffer)?;
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Ok(Self {
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kind: RequestKind::Command,
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body,
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})
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}
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pub fn match_str(&mut self, prefix: &str) -> bool {
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if let Some(new_body) = self.body.strip_prefix(prefix) {
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self.body = new_body;
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return true;
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}
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false
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}
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}
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