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use std::collections::VecDeque;
use std::{cell::RefCell, fmt, future::Future, pin::Pin, rc::Rc, task::Context, task::Poll};
use ntex::io::{IoBoxed, IoRef, OnDisconnect};
use ntex::util::{poll_fn, ready, Either, Ready};
use ntex::{channel::pool, service::Service};
use super::cmd::Command;
use super::codec::{Codec, Request, Response};
use super::errors::{CommandError, Error};
type Queue = Rc<RefCell<VecDeque<pool::Sender<Result<Response, Error>>>>>;
#[derive(Clone)]
pub struct Client {
io: IoRef,
queue: Queue,
disconnect: OnDisconnect,
pool: pool::Pool<Result<Response, Error>>,
}
impl Client {
pub(crate) fn new(io: IoBoxed) -> Self {
let queue: Queue = Rc::new(RefCell::new(VecDeque::new()));
let io_ref = io.get_ref();
let queue2 = queue.clone();
ntex::rt::spawn(async move {
poll_fn(|cx| loop {
match ready!(io.poll_read_next(&Codec, cx)) {
Some(Ok(item)) => {
if let Some(tx) = queue2.borrow_mut().pop_front() {
let _ = tx.send(Ok(item));
} else {
log::error!("Unexpected redis response: {:?}", item);
}
continue;
}
Some(Err(Either::Left(e))) => {
if let Some(tx) = queue2.borrow_mut().pop_front() {
let _ = tx.send(Err(e));
}
queue2.borrow_mut().clear();
let _ = ready!(io.poll_shutdown(cx));
return Poll::Ready(());
}
Some(Err(Either::Right(e))) => {
if let Some(tx) = queue2.borrow_mut().pop_front() {
let _ = tx.send(Err(e.into()));
}
queue2.borrow_mut().clear();
let _ = ready!(io.poll_shutdown(cx));
return Poll::Ready(());
}
None => return Poll::Ready(()),
}
})
.await
});
let disconnect = io_ref.on_disconnect();
Client {
queue,
disconnect,
io: io_ref,
pool: pool::new(),
}
}
pub fn exec<T>(&self, cmd: T) -> impl Future<Output = Result<T::Output, CommandError>>
where
T: Command,
{
let is_open = !self.io.is_closed();
let fut = self.call(cmd.to_request());
async move {
if !is_open {
Err(CommandError::Protocol(Error::Disconnected))
} else {
fut.await
.map_err(CommandError::Protocol)
.and_then(|res| T::to_output(res.into_result().map_err(CommandError::Error)?))
}
}
}
pub async fn flushdb(&self) -> Result<(), Error> {
self.call("FLUSHDB".into()).await?;
Ok(())
}
pub fn is_connected(&self) -> bool {
!self.io.is_closed()
}
}
impl Service for Client {
type Request = Request;
type Response = Response;
type Error = Error;
type Future = Either<CommandResult, Ready<Response, Error>>;
fn poll_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
if self.disconnect.poll_ready(cx).is_ready() {
Poll::Ready(Err(Error::Disconnected))
} else {
Poll::Ready(Ok(()))
}
}
fn call(&self, req: Request) -> Self::Future {
if let Err(e) = self.io.encode(req, &Codec) {
Either::Right(Ready::Err(e))
} else {
let (tx, rx) = self.pool.channel();
self.queue.borrow_mut().push_back(tx);
Either::Left(CommandResult { rx })
}
}
}
impl fmt::Debug for Client {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Client")
.field("connected", &!self.io.is_closed())
.finish()
}
}
pub struct CommandResult {
rx: pool::Receiver<Result<Response, Error>>,
}
impl Future for CommandResult {
type Output = Result<Response, Error>;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
match Pin::new(&mut self.rx).poll(cx) {
Poll::Ready(Ok(res)) => Poll::Ready(res),
Poll::Ready(Err(_)) => Poll::Ready(Err(Error::Disconnected)),
Poll::Pending => Poll::Pending,
}
}
}