From c47f2139a33973dcdd5d76eedbd41dabb359a288 Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Fri, 19 Aug 2022 20:31:36 +0200
Subject: [PATCH] Use a Parker instead of a channel in JACK backend
---
src/wrapper/standalone/backend/jack.rs | 28 ++++++++------------------
1 file changed, 8 insertions(+), 20 deletions(-)
diff --git a/src/wrapper/standalone/backend/jack.rs b/src/wrapper/standalone/backend/jack.rs
index aef9b8fd..5f56571c 100644
--- a/src/wrapper/standalone/backend/jack.rs
+++ b/src/wrapper/standalone/backend/jack.rs
@@ -1,7 +1,7 @@
use std::sync::Arc;
use anyhow::{Context, Result};
-use crossbeam::channel;
+use crossbeam::sync::Parker;
use jack::{
AsyncClient, AudioIn, AudioOut, Client, ClientOptions, ClosureProcessHandler, Control, MidiIn,
MidiOut, Port,
@@ -28,12 +28,6 @@ pub struct Jack {
midi_output: Option<Arc<Mutex<Port<MidiOut>>>>,
}
-/// A simple message to tell the audio thread to shut down, since the actual processing happens in
-/// these callbacks.
-enum Task {
- Shutdown,
-}
-
impl Backend for Jack {
fn run(
&mut self,
@@ -54,7 +48,10 @@ impl Backend for Jack {
let mut input_events = Vec::with_capacity(2048);
let mut output_events = Vec::with_capacity(2048);
- let (control_sender, control_receiver) = channel::bounded(32);
+ // This thread needs to be blocked until processing is finished
+ let parker = Parker::new();
+ let unparker = parker.unparker().clone();
+
let config = self.config.clone();
let inputs = self.inputs.clone();
let outputs = self.outputs.clone();
@@ -69,7 +66,7 @@ impl Backend for Jack {
"Buffer size changed from {buffer_size} to {num_frames}. Buffer size changes \
are currently not supported, aborting..."
);
- control_sender.send(Task::Shutdown).unwrap();
+ unparker.unpark();
return Control::Quit;
}
@@ -153,7 +150,7 @@ impl Backend for Jack {
Control::Continue
} else {
- control_sender.send(Task::Shutdown).unwrap();
+ unparker.unpark();
Control::Quit
}
});
@@ -168,16 +165,7 @@ impl Backend for Jack {
// The process callback happens on another thread, so we need to block this thread until we
// get the request to shut down or until the process callback runs into an error
- #[allow(clippy::never_loop)]
- loop {
- match control_receiver.recv() {
- Ok(Task::Shutdown) => break,
- Err(err) => {
- nih_debug_assert_failure!("Error reading from channel: {}", err);
- break;
- }
- }
- }
+ parker.park();
// And put the client back where it belongs in case this function is called a second time
let (client, _, _) = async_client.deactivate().unwrap();