stop using tokio::select!

3 files changed, 106 insertions, 54 deletions

diff --git a/src/bin/rbw-agent/agent.rs b/src/bin/rbw-agent/agent.rs
index b36fbb7..8fa6768 100644
--- a/src/bin/rbw-agent/agent.rs
+++ b/src/bin/rbw-agent/agent.rs
@@ -1,16 +1,12 @@
 use anyhow::Context as _;
-
-#[derive(Debug)]
-pub enum TimeoutEvent {
-    Set,
-    Clear,
-}
+use futures_util::StreamExt as _;
 
 pub struct State {
     pub priv_key: Option<rbw::locked::Keys>,
     pub org_keys:
         Option<std::collections::HashMap<String, rbw::locked::Keys>>,
-    pub timeout_chan: tokio::sync::mpsc::UnboundedSender<TimeoutEvent>,
+    pub timeout: crate::timeout::Timeout,
+    pub timeout_duration: std::time::Duration,
 }
 
 impl State {
@@ -25,22 +21,18 @@ impl State {
     }
 
     pub fn set_timeout(&mut self) {
-        // no real better option to unwrap here
-        self.timeout_chan.send(TimeoutEvent::Set).unwrap();
+        self.timeout.set(self.timeout_duration);
     }
 
     pub fn clear(&mut self) {
         self.priv_key = None;
         self.org_keys = None;
-        // no real better option to unwrap here
-        self.timeout_chan.send(TimeoutEvent::Clear).unwrap();
+        self.timeout.clear();
     }
 }
 
 pub struct Agent {
-    timeout_duration: tokio::time::Duration,
-    timeout: Option<std::pin::Pin<Box<tokio::time::Sleep>>>,
-    timeout_chan: tokio::sync::mpsc::UnboundedReceiver<TimeoutEvent>,
+    timer_r: tokio::sync::mpsc::UnboundedReceiver<()>,
     state: std::sync::Arc<tokio::sync::RwLock<State>>,
 }
 
@@ -48,70 +40,63 @@ impl Agent {
     pub fn new() -> anyhow::Result<Self> {
         let config = rbw::config::Config::load()?;
         let timeout_duration =
-            tokio::time::Duration::from_secs(config.lock_timeout);
-        let (w, r) = tokio::sync::mpsc::unbounded_channel();
+            std::time::Duration::from_secs(config.lock_timeout);
+        let (timeout, timer_r) = crate::timeout::Timeout::new();
         Ok(Self {
-            timeout_duration,
-            timeout: None,
-            timeout_chan: r,
+            timer_r,
             state: std::sync::Arc::new(tokio::sync::RwLock::new(State {
                 priv_key: None,
                 org_keys: None,
-                timeout_chan: w,
+                timeout,
+                timeout_duration,
             })),
         })
     }
 
-    fn set_timeout(&mut self) {
-        self.timeout =
-            Some(Box::pin(tokio::time::sleep(self.timeout_duration)));
-    }
-
-    fn clear_timeout(&mut self) {
-        self.timeout = None;
-    }
-
     pub async fn run(
-        &mut self,
+        self,
         listener: tokio::net::UnixListener,
     ) -> anyhow::Result<()> {
-        // tokio only supports timeouts up to 2^36 milliseconds
-        let mut forever = Box::pin(tokio::time::sleep(
-            tokio::time::Duration::from_secs(60 * 60 * 24 * 365 * 2),
-        ));
-        loop {
-            let timeout = self.timeout.as_mut().unwrap_or(&mut forever);
-            tokio::select! {
-                sock = listener.accept() => {
+        enum Event {
+            Request(std::io::Result<tokio::net::UnixStream>),
+            Timeout(()),
+        }
+        let mut stream = futures_util::stream::select_all([
+            tokio_stream::wrappers::UnixListenerStream::new(listener)
+                .map(Event::Request)
+                .boxed(),
+            tokio_stream::wrappers::UnboundedReceiverStream::new(
+                self.timer_r,
+            )
+            .map(Event::Timeout)
+            .boxed(),
+        ]);
+        while let Some(event) = stream.next().await {
+            match event {
+                Event::Request(res) => {
                     let mut sock = crate::sock::Sock::new(
-                        sock.context("failed to accept incoming connection")?.0
+                        res.context("failed to accept incoming connection")?,
                     );
                     let state = self.state.clone();
                     tokio::spawn(async move {
-                        let res
-                            = handle_request(&mut sock, state.clone()).await;
+                        let res =
+                            handle_request(&mut sock, state.clone()).await;
                         if let Err(e) = res {
                             // unwrap is the only option here
                             sock.send(&rbw::protocol::Response::Error {
                                 error: format!("{e:#}"),
-                            }).await.unwrap();
+                            })
+                            .await
+                            .unwrap();
                         }
                     });
                 }
-                _ = timeout => {
-                    let state = self.state.clone();
-                    tokio::spawn(async move{
-                        state.write().await.clear();
-                    });
-                }
-                Some(ev) = self.timeout_chan.recv() => {
-                    match ev {
-                        TimeoutEvent::Set => self.set_timeout(),
-                        TimeoutEvent::Clear => self.clear_timeout(),
-                    }
+                Event::Timeout(()) => {
+                    self.state.write().await.clear();
                 }
             }
         }
+        Ok(())
     }
 }
 
diff --git a/src/bin/rbw-agent/main.rs b/src/bin/rbw-agent/main.rs
index ad1fe80..81eee3a 100644
--- a/src/bin/rbw-agent/main.rs
+++ b/src/bin/rbw-agent/main.rs
@@ -20,6 +20,7 @@ mod agent;
 mod daemon;
 mod debugger;
 mod sock;
+mod timeout;
 
 async fn tokio_main(
     startup_ack: Option<crate::daemon::StartupAck>,
@@ -30,7 +31,7 @@ async fn tokio_main(
         startup_ack.ack()?;
     }
 
-    let mut agent = crate::agent::Agent::new()?;
+    let agent = crate::agent::Agent::new()?;
     agent.run(listener).await?;
 
     Ok(())
diff --git a/src/bin/rbw-agent/timeout.rs b/src/bin/rbw-agent/timeout.rs
new file mode 100644
index 0000000..e613ff0
--- /dev/null
+++ b/src/bin/rbw-agent/timeout.rs
@@ -0,0 +1,66 @@
+use futures_util::StreamExt as _;
+
+#[derive(Debug, Hash, Eq, PartialEq, Copy, Clone)]
+enum Streams {
+    Requests,
+    Timer,
+}
+
+#[derive(Debug)]
+enum Action {
+    Set(std::time::Duration),
+    Clear,
+}
+
+pub struct Timeout {
+    req_w: tokio::sync::mpsc::UnboundedSender<Action>,
+}
+
+impl Timeout {
+    pub fn new() -> (Self, tokio::sync::mpsc::UnboundedReceiver<()>) {
+        let (req_w, req_r) = tokio::sync::mpsc::unbounded_channel();
+        let (timer_w, timer_r) = tokio::sync::mpsc::unbounded_channel();
+        tokio::spawn(async move {
+            enum Event {
+                Request(Action),
+                Timer,
+            }
+            let mut stream = tokio_stream::StreamMap::new();
+            stream.insert(
+                Streams::Requests,
+                tokio_stream::wrappers::UnboundedReceiverStream::new(req_r)
+                    .map(Event::Request)
+                    .boxed(),
+            );
+            while let Some(event) = stream.next().await {
+                match event {
+                    (_, Event::Request(Action::Set(dur))) => {
+                        stream.insert(
+                            Streams::Timer,
+                            futures_util::stream::once(tokio::time::sleep(
+                                dur,
+                            ))
+                            .map(|_| Event::Timer)
+                            .boxed(),
+                        );
+                    }
+                    (_, Event::Request(Action::Clear)) => {
+                        stream.remove(&Streams::Timer);
+                    }
+                    (_, Event::Timer) => {
+                        timer_w.send(()).unwrap();
+                    }
+                }
+            }
+        });
+        (Self { req_w }, timer_r)
+    }
+
+    pub fn set(&self, dur: std::time::Duration) {
+        self.req_w.send(Action::Set(dur)).unwrap();
+    }
+
+    pub fn clear(&self) {
+        self.req_w.send(Action::Clear).unwrap();
+    }
+}