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use super::parser::Error as ParserError;
use super::parser::Parser;
use super::parser::State as ParserState;
use crate::common::db::Database;
use crate::common::expr::Expr;
use crate::common::query::Error as QueryError;
use crate::common::query::Query;
use crate::common::sized_buffer::SizedBuffer;
use crate::server::CONN_BUFLEN;
use log::debug;
use log::error;
use mio::net::TcpStream;
use mio::Token;
use std::fmt;
use std::fmt::Display;
use std::fmt::Formatter;
use std::io::ErrorKind;
use std::io::Read;
use std::io::Write;
#[derive(Debug)]
pub enum Error {
IO(std::io::Error),
Parser(ParserError),
Query(QueryError),
Fatal,
}
#[derive(Eq, PartialEq, Debug)]
#[repr(u8)]
pub enum State {
PendingExec = 0b100,
ReadReady = 0b010,
WriteReady = 0b001,
}
pub struct Conn {
pub flags: u8,
socket: TcpStream,
token: Token,
parser: Parser,
buf_in: SizedBuffer<[u8; CONN_BUFLEN]>,
buf_out: Vec<u8>,
}
impl Conn {
pub fn new(socket: TcpStream, token: Token) -> Self {
Self {
flags: State::ReadReady as u8,
socket,
token,
parser: Parser::new(),
buf_in: SizedBuffer::new(),
buf_out: Vec::new(),
}
}
pub fn handle_pending(&mut self, db: &mut Database) -> Result<(), Error> {
self.handle_msg(db, &[])
}
pub fn handle_msg(&mut self, db: &mut Database, msg: &[u8]) -> Result<(), Error> {
if let Err(err) = self.buf_in.append(&mut msg.to_vec()) {
error!("[{self}] ! Error while writing to the buffer: {err:?}");
return Err(Error::Fatal);
}
match self.parser.parse(&mut self.buf_in) {
Ok(ParserState::Wait) => Ok(()),
Ok(ParserState::Done(argv)) => {
Query::from_expr(Expr::Array(
argv.iter().map(|x| Expr::Blob(x.to_vec())).collect(),
))
.map(|query| {
debug!("[{self}] < {query}");
let resp = query.exec(db);
self.draft(&resp.encode());
if self.buf_in.empty() {
self.buf_in.reset();
self.flags &= !(State::PendingExec as u8);
} else {
self.flags &= !(State::ReadReady as u8);
self.flags |= State::PendingExec as u8;
}
debug!("[{self}] > {resp}");
})
.map_err(|e| {
debug!("[{self}] ! {e:?}");
let wrapped_err = Error::Query(e);
let resp = Expr::Error {
code: error_code(&wrapped_err),
msg: format!("{}", wrapped_err).into_bytes(),
};
self.draft(&resp.encode());
if self.buf_in.empty() {
self.buf_in.reset();
self.flags &= !(State::PendingExec as u8);
} else {
self.flags &= !(State::ReadReady as u8);
self.flags |= State::PendingExec as u8;
}
wrapped_err
})?;
Ok(())
}
Err(err) => {
let wrapped_err = Error::Parser(err);
debug!("[{self}] ! {wrapped_err}");
let resp = Expr::Error {
code: error_code(&wrapped_err),
msg: format!("{}", wrapped_err).into_bytes(),
};
self.draft(&resp.encode());
/* If there's a parsing error, we throw away the entire buffer. This means
* potentially throwing away valid commands appearing later in the buffer */
self.buf_in.reset();
self.flags &= !(State::PendingExec as u8);
Err(wrapped_err)
}
}
}
fn draft(&mut self, msg: &[u8]) {
self.buf_out = msg.to_vec();
self.flags = State::WriteReady as u8;
}
pub fn reply(&mut self) -> Result<(), Error> {
assert!(self.write_ready());
match self.socket.write(&self.buf_out) {
Ok(wrote_len) if wrote_len == self.buf_out.len() => {
self.flags &= !(State::WriteReady as u8);
/* Full write, we're ready to accept more data. If there are still queries waiting
* to be processed in the buffer, wait until these are processed first. */
if !self.pending_exec() {
self.flags |= State::ReadReady as u8;
}
if let Err(e) = self.socket.flush() {
return Err(Error::IO(e));
}
Ok(())
}
Ok(_wrote_len) => {
/* Partial write, track the remaining length */
self.flags |= State::WriteReady as u8;
Ok(())
}
Err(e) if e.kind() == ErrorKind::BrokenPipe => Err(Error::IO(e)),
Err(e) if e.kind() == ErrorKind::ConnectionReset => Err(Error::IO(e)),
Err(e) => panic!("FATAL | Unexpected error: {e:?}"),
}
}
pub fn pending_exec(&self) -> bool {
self.flags & State::PendingExec as u8 > 0
}
pub fn read_ready(&self) -> bool {
self.flags & State::ReadReady as u8 > 0
}
pub fn write_ready(&self) -> bool {
self.flags & State::WriteReady as u8 > 0
}
}
impl Read for Conn {
fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
assert!(self.read_ready());
self.socket.read(buf)
}
}
impl Write for Conn {
fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {
self.socket.write(buf)
}
fn flush(&mut self) -> Result<(), std::io::Error> {
self.socket.flush()
}
}
impl Display for Conn {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
match self.socket.peer_addr() {
Ok(addr) => write!(f, "{addr} #{}", self.token.0),
Err(_) => write!(f, "unknown-addr #{}", self.token.0),
}
}
}
// Errors
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let res = match self {
Error::IO(err) => format!("IO error: {err:?}"),
Error::Parser(err) => err.to_string(),
Error::Query(err) => err.to_string(),
Error::Fatal => "Fatal error".to_string(),
};
write!(f, "{}", res)
}
}
fn error_code(error: &Error) -> Vec<u8> {
let code = match error {
Error::IO(_) => "SERVER",
Error::Parser(_) => "PROTOCOL",
Error::Query(_) => "QUERY",
Error::Fatal => "SERVER",
};
code.as_bytes().to_vec()
}
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