wip: connect devices

src/core.rs

@@ -24,14 +24,14 @@ pub trait Component: Render + Handle {}
 impl<T: Render + Handle> Component for T {}
 
 /// A UI component that may have presence on the JACK grap.
-pub trait Device: Render + Handle + Ports + Send + Sync {
+pub trait Device: Render + Handle + Process + Ports + Send + Sync {
     fn boxed (self) -> Box<dyn Device> where Self: Sized + 'static {
         Box::new(self)
     }
 }
 
 /// All things that implement the required traits can be treated as `Device`.
-impl<T: Render + Handle + Ports + Send + Sync> Device for T {}
+impl<T: Render + Handle + Process + Ports + Send + Sync> Device for T {}
 
 // Reexport macros:
 pub use crate::{

src/core/jack.rs

@@ -1,5 +1,114 @@
 use crate::core::*;
 
+pub struct Jack {
+    pub client: JackClient,
+    pub ports:  JackPorts,
+}
+
+pub enum JackClient {
+    Active(DynamicAsyncClient),
+    Inactive(Client),
+}
+
+#[derive(Default)]
+pub struct JackPorts {
+    pub audio_ins:  BTreeMap<String, Port<AudioIn>>,
+    pub midi_ins:   BTreeMap<String, Port<MidiIn>>,
+    pub audio_outs: BTreeMap<String, Port<AudioOut>>,
+    pub midi_outs:  BTreeMap<String, Port<MidiOut>>,
+}
+
+ports!(Jack {
+    audio: {
+        ins:  |s|Ok(s.ports.audio_ins.values().collect()),
+        outs: |s|Ok(s.ports.audio_outs.values().collect()),
+    }
+    midi: {
+        ins:  |s|Ok(s.ports.midi_ins.values().collect()),
+        outs: |s|Ok(s.ports.midi_outs.values().collect()),
+    }
+});
+
+impl Jack {
+    pub fn new (name: &str) -> Usually<Self> {
+        let (client, _) = Client::new(name, ClientOptions::NO_START_SERVER)?;
+        Ok(Self { client: JackClient::Inactive(client), ports: JackPorts::default(), })
+    }
+    pub fn ports_from_lv2 (self, plugin: &::livi::Plugin) -> Usually<Self> {
+        let counts = plugin.port_counts();
+        let mut jack = self;
+        for i in 0..counts.atom_sequence_inputs {
+            jack = jack.register_midi_in(&format!("midi-in-{i}"))?
+        }
+        for i in 0..counts.atom_sequence_outputs {
+            jack = jack.register_midi_out(&format!("midi-out-{i}"))?;
+        }
+        for i in 0..counts.audio_inputs {
+            jack = jack.register_audio_in(&format!("audio-in-{i}"))?
+        }
+        for i in 0..counts.audio_outputs {
+            jack = jack.register_audio_out(&format!("audio-out-{i}"))?;
+        }
+        Ok(jack)
+    }
+    pub fn register_midi_out (mut self, name: &str) -> Usually<Self> {
+        self.ports.midi_outs.insert(name.to_string(), match &self.client {
+            JackClient::Inactive(c) => c.register_port(name, MidiOut::default())?,
+            JackClient::Active(c) => c.as_client().register_port(name, MidiOut::default())?,
+        });
+        Ok(self)
+    }
+    pub fn register_midi_in (mut self, name: &str) -> Usually<Self> {
+        self.ports.midi_ins.insert(name.to_string(), match &self.client {
+            JackClient::Inactive(c) => c.register_port(name, MidiIn::default())?,
+            JackClient::Active(c) => c.as_client().register_port(name, MidiIn::default())?,
+        });
+        Ok(self)
+    }
+    pub fn register_audio_out (mut self, name: &str) -> Usually<Self> {
+        self.ports.audio_outs.insert(name.to_string(), match &self.client {
+            JackClient::Inactive(c) => c.register_port(name, AudioOut::default())?,
+            JackClient::Active(c) => c.as_client().register_port(name, AudioOut::default())?,
+        });
+        Ok(self)
+    }
+    pub fn register_audio_in (mut self, name: &str) -> Usually<Self> {
+        self.ports.audio_ins.insert(name.to_string(), match &self.client {
+            JackClient::Inactive(c) => c.register_port(name, AudioIn::default())?,
+            JackClient::Active(c) => c.as_client().register_port(name, AudioIn::default())?,
+        });
+        Ok(self)
+    }
+    pub fn run <T> (
+        mut self, state: impl FnOnce(JackPorts)->Box<T>
+    ) -> Usually<Arc<Mutex<Box<dyn Device>>>>  where
+        T: Device + Process + Sized + 'static
+    {
+        let mut ports = JackPorts::default();
+        std::mem::swap(&mut self.ports, &mut ports);
+        let state = Arc::new(Mutex::new(state(ports) as Box<dyn Device>));
+        self.client = match self.client {
+            JackClient::Active(_) => panic!("already running"),
+            JackClient::Inactive(client) => JackClient::Active(client.activate_async(
+                Notifications(Box::new({
+                    let _state = state.clone();
+                    move|_event|{
+                        // FIXME: this deadlocks
+                        //state.lock().unwrap().handle(&event).unwrap();
+                    }
+                }) as Box<dyn Fn(AppEvent) + Send + Sync>),
+                ClosureProcessHandler::new(Box::new({
+                    let state = state.clone();
+                    move|c: &Client, s: &ProcessScope|{
+                        state.lock().unwrap().process(c, s)
+                    }
+                }) as BoxedProcessHandler)
+            )?)
+        };
+        Ok(state)
+    }
+}
+
 pub fn jack_run <T> (name: &str, app: &Arc<Mutex<T>>) -> Usually<DynamicAsyncClient>
     where T: Handle + Process + Send + 'static
 {

src/core/port.rs

@@ -2,10 +2,10 @@ use crate::core::*;
 
 /// Trait for things that may expose JACK ports.
 pub trait Ports {
-    fn audio_ins  (&self) -> Usually<Vec<&Port<AudioIn>>> {
+    fn audio_ins  <'a> (&'a self) -> Usually<Vec<&'a Port<AudioIn>>> {
         Ok(vec![])
     }
-    fn audio_outs (&self) -> Usually<Vec<&Port<AudioOut>>> {
+    fn audio_outs <'a> (&'a self) -> Usually<Vec<&'a Port<AudioOut>>> {
         Ok(vec![])
     }
     fn midi_ins  <'a> (&'a self) -> Usually<Vec<&'a Port<MidiIn>>> {

src/core/render.rs

@@ -1,6 +1,19 @@
 use crate::core::*;
 use ratatui::widgets::WidgetRef;
 
+pub trait Blit {
+    // Render something to X, Y coordinates in a buffer, ignoring width/height.
+    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>);
+}
+
+impl<T: AsRef<str>> Blit for T {
+    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) {
+        if x < buf.area.width && y < buf.area.height {
+            buf.set_string(x, y, self.as_ref(), style.unwrap_or(Style::default()))
+        }
+    }
+}
+
 /// Trait for things that render to the display.
 pub trait Render: Send {
     // Render something to an area of the buffer.
@@ -43,6 +56,12 @@ impl Render for Box<dyn Device> {
     }
 }
 
+impl<T: Render> Render for Arc<Mutex<T>> {
+    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
+        self.lock().unwrap().render(b, a)
+    }
+}
+
 impl WidgetRef for &dyn Render {
     fn render_ref (&self, area: Rect, buf: &mut Buffer) {
         Render::render(*self, buf, area).expect("Failed to render device.");
@@ -54,16 +73,3 @@ impl WidgetRef for dyn Render {
         Render::render(self, buf, area).expect("Failed to render device.");
     }
 }
-
-pub trait Blit {
-    // Render something to X, Y coordinates in a buffer, ignoring width/height.
-    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>);
-}
-
-impl<T: AsRef<str>> Blit for T {
-    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) {
-        if x < buf.area.width && y < buf.area.height {
-            buf.set_string(x, y, self.as_ref(), style.unwrap_or(Style::default()))
-        }
-    }
-}

src/main.rs

@@ -24,36 +24,39 @@ pub fn main () -> Usually<()> {
             state.modal = Some(Box::new(crate::config::SetupModal(Some(xdg.clone()))));
         }
         state.scenes = vec![
-            Scene::new("Intro", vec![None,    Some(0), None, None]),
-            Scene::new("Hook",  vec![Some(0), Some(0), None, None]),
+            Scene::new("Intro",  vec![None,    Some(0), None, None]),
+            Scene::new("Hook",   vec![Some(0), Some(0), None, None]),
+            Scene::new("Verse",  vec![None,    Some(0), None, None]),
+            Scene::new("Chorus", vec![None,    Some(0), None, None]),
+            Scene::new("Bridge", vec![None,    Some(0), None, None]),
+            Scene::new("Outro",  vec![None,    Some(0), None, None]),
         ];
-        let jack = jack_run("tek", &app)?;
+        let jack     = jack_run("tek", &app)?;
+        let client   = jack.as_client();
         let timebase = &state.timebase;
-        let ppq = timebase.ppq() as usize;
+        let ppq      = timebase.ppq() as usize;
         state.tracks = vec![
 
             Track::new("Drums", &jack.as_client(), Some(vec![
-                Sampler::new("Sampler", Some(BTreeMap::from([
-                    sample!(36, "Kick",  "/home/user/Lab/Music/pak/kik.wav"),
-                    sample!(40, "Snare", "/home/user/Lab/Music/pak/sna.wav"),
-                    sample!(44, "Hihat", "/home/user/Lab/Music/pak/chh.wav"),
-                ])))?.boxed(),
-                Plugin::lv2(
-                    "Panagement",
-                    "file:///home/user/.lv2/Auburn Sounds Panagement 2.lv2"
-                )?.boxed(),
-            ]), Some(vec![
                 Phrase::new("4 kicks", ppq * 4, Some(phrase! {
                     00 * ppq/4 => MidiMessage::NoteOn { key: 36.into(), vel: 100.into() },
                     04 * ppq/4 => MidiMessage::NoteOn { key: 36.into(), vel: 100.into() },
                     08 * ppq/4 => MidiMessage::NoteOn { key: 36.into(), vel: 100.into() },
                     12 * ppq/4 => MidiMessage::NoteOn { key: 36.into(), vel: 100.into() },
                 })),
-            ]))?,
+            ]), Some(vec![
+                Sampler::new("Sampler", Some(BTreeMap::from([
+                    sample!(36, "Kick",  "/home/user/Lab/Music/pak/kik.wav"),
+                    sample!(40, "Snare", "/home/user/Lab/Music/pak/sna.wav"),
+                    sample!(44, "Hihat", "/home/user/Lab/Music/pak/chh.wav"),
+                ])))?,
+                Plugin::lv2(
+                    "Panagement",
+                    "file:///home/user/.lv2/Auburn Sounds Panagement 2.lv2"
+                )?,
+            ]),)?,
 
             Track::new("Bass", &jack.as_client(), Some(vec![
-                Plugin::lv2("Odin2", "file:///home/user/.lv2/Odin2.lv2")?.boxed(),
-            ]), Some(vec![
                 Phrase::new("Offbeat", ppq * 4, Some(phrase! {
                     00 * ppq/4 => MidiMessage::NoteOff { key: 40.into(), vel: 100.into() },
                     02 * ppq/4 => MidiMessage::NoteOn  { key: 40.into(), vel: 100.into() },
@@ -64,6 +67,8 @@ pub fn main () -> Usually<()> {
                     12 * ppq/4 => MidiMessage::NoteOff { key: 40.into(), vel: 100.into() },
                     14 * ppq/4 => MidiMessage::NoteOn  { key: 40.into(), vel: 100.into() },
                 })),
+            ]), Some(vec![
+                Plugin::lv2("Odin2", "file:///home/user/.lv2/Odin2.lv2")?,
             ]))?,
 
         ];
@@ -72,7 +77,6 @@ pub fn main () -> Usually<()> {
         state.track_cursor = 1;
         state.scene_cursor = 1;
         state.note_start   = 12;
-        let client = jack.as_client();
         //for track in state.tracks.iter() {
             //if let Some(port) = track.midi_ins()?.get(0) {
                 //client.connect_ports(&track.midi_out, port)?;

src/model/plugin.rs

@@ -7,28 +7,24 @@ pub mod vst3;
 use self::lv2::*;
 
 pub struct Plugin {
-    pub name:       String,
-    pub path:       Option<String>,
-    pub plugin:     Option<PluginKind>,
-    pub selected:   usize,
-    pub mapping:    bool,
-    pub midi_ins:   Vec<Port<MidiIn>>,
-    pub midi_outs:  Vec<Port<MidiOut>>,
-    pub audio_ins:  Vec<Port<AudioIn>>,
-    pub audio_outs: Vec<Port<AudioOut>>,
-    pub jack:       Client,
+    pub name:     String,
+    pub path:     Option<String>,
+    pub plugin:   Option<PluginKind>,
+    pub selected: usize,
+    pub mapping:  bool,
+    pub ports:    JackPorts,
 }
 render!(Plugin = crate::view::plugin::render);
 handle!(Plugin = crate::control::plugin::handle);
 process!(Plugin = Plugin::process);
 ports!(Plugin {
     audio: {
-        ins:  |track|Ok(track.audio_ins.iter().collect()),
-        outs: |track|Ok(track.audio_outs.iter().collect()),
+        ins:  |p|Ok(p.ports.audio_ins.values().collect()),
+        outs: |p|Ok(p.ports.audio_outs.values().collect()),
     }
     midi: {
-        ins:  |track|Ok(track.midi_ins.iter().collect()),
-        outs: |track|Ok(track.midi_outs.iter().collect()),
+        ins:  |p|Ok(p.ports.midi_ins.values().collect()),
+        outs: |p|Ok(p.ports.midi_outs.values().collect()),
     }
 });
 
@@ -41,20 +37,15 @@ pub enum PluginKind {
 }
 
 impl Plugin {
-    /// Load a LV2 plugin.
+    /// Create a plugin host device.
     pub fn new (name: &str) -> Usually<Self> {
-        let (jack, _) = Client::new(name, ClientOptions::NO_START_SERVER)?;
         Ok(Self {
             name:       name.into(),
             path:       None,
             plugin:     None,
             selected:   0,
             mapping:    false,
-            midi_ins:   vec![],
-            midi_outs:  vec![],
-            audio_ins:  vec![],
-            audio_outs: vec![],
-            jack,
+            ports:      JackPorts::default()
         })
     }
     pub fn process (&mut self, _: &Client, scope: &ProcessScope) -> Control {
@@ -62,7 +53,7 @@ impl Plugin {
             Some(PluginKind::LV2(LV2Plugin { features, ref mut instance, .. })) => {
                 let urid = features.midi_urid();
                 let mut inputs = vec![];
-                for port in self.midi_ins.iter() {
+                for port in self.ports.midi_ins.values() {
                     let mut atom = ::livi::event::LV2AtomSequence::new(
                         &features,
                         scope.n_frames() as usize
@@ -80,7 +71,7 @@ impl Plugin {
                     inputs.push(atom);
                 }
                 let mut outputs = vec![];
-                for _ in self.midi_outs.iter() {
+                for _ in self.ports.midi_outs.iter() {
                     outputs.push(::livi::event::LV2AtomSequence::new(
                         &features,
                         scope.n_frames() as usize
@@ -94,10 +85,10 @@ impl Plugin {
                         outputs.iter_mut()
                     )
                     .with_audio_inputs(
-                        self.audio_ins.iter().map(|o|o.as_slice(scope))
+                        self.ports.audio_ins.values().map(|o|o.as_slice(scope))
                     )
                     .with_audio_outputs(
-                        self.audio_outs.iter_mut().map(|o|o.as_mut_slice(scope))
+                        self.ports.audio_outs.values_mut().map(|o|o.as_mut_slice(scope))
                     );
                 unsafe {
                     instance.run(scope.n_frames() as usize, ports).unwrap()

src/model/plugin/lv2.rs

@@ -41,46 +41,17 @@ impl LV2Plugin {
 }
 
 impl super::Plugin {
-    pub fn lv2 (name: &str, path: &str) -> Usually<Self> {
-        let mut host = Self::new(name)?;
+    pub fn lv2 (name: &str, path: &str) -> Usually<Arc<Mutex<Box<dyn Device>>>> {
         let plugin = LV2Plugin::new(path)?;
-        let client = &host.jack;
-        let (midi_ins, midi_outs, audio_ins, audio_outs) = (
-            plugin.plugin.port_counts().atom_sequence_inputs,
-            plugin.plugin.port_counts().atom_sequence_outputs,
-            plugin.plugin.port_counts().audio_inputs,
-            plugin.plugin.port_counts().audio_outputs,
-        );
-        host.midi_ins = {
-            let mut ports = vec![];
-            for i in 0..midi_ins {
-                ports.push(client.register_port(&format!("midi-in-{i}"), MidiIn::default())?)
-            }
-            ports
-        };
-        host.midi_outs = {
-            let mut ports = vec![];
-            for i in 0..midi_outs {
-                ports.push(client.register_port(&format!("midi-out-{i}"), MidiOut::default())?)
-            }
-            ports
-        };
-        host.audio_ins = {
-            let mut ports = vec![];
-            for i in 0..audio_ins {
-                ports.push(client.register_port(&format!("audio-in-{i}"), AudioIn::default())?)
-            }
-            ports
-        };
-        host.audio_outs = {
-            let mut ports = vec![];
-            for i in 0..audio_outs {
-                ports.push(client.register_port(&format!("audio-out-{i}"), AudioOut::default())?)
-            }
-            ports
-        };
-        host.plugin = Some(super::PluginKind::LV2(plugin));
-        host.path   = Some(String::from(path));
-        Ok(host)
+        Jack::new(name)?
+            .ports_from_lv2(&plugin.plugin)?
+            .run(|ports|Box::new(Self {
+                name:       name.into(),
+                path:       Some(String::from(path)),
+                plugin:     Some(super::PluginKind::LV2(plugin)),
+                selected:   0,
+                mapping:    false,
+                ports
+            }))
     }
 }

src/model/sampler.rs

@@ -13,17 +13,6 @@ pub struct Sample {
     pub channels: Vec<Vec<f32>>,
 }
 
-pub struct Sampler {
-    pub name:       String,
-    pub jack:       Client,
-    pub cursor:     (usize, usize),
-    pub samples:    BTreeMap<u7, Arc<Sample>>,
-    pub voices:     Vec<Voice>,
-    pub midi_in:    Port<MidiIn>,
-    pub audio_ins:  Vec<Port<AudioIn>>,
-    pub audio_outs: Vec<Port<AudioOut>>,
-}
-
 impl Voice {
     pub fn chunk (&mut self, mut frames: usize) -> Option<Vec<Vec<f32>>> {
         // Create output buffer for each channel
@@ -62,46 +51,65 @@ impl Sample {
         Voice { sample: self.clone(), after, position: self.start }
     }
 }
+
+pub struct Sampler {
+    pub name:    String,
+    pub cursor:  (usize, usize),
+    pub samples: BTreeMap<u7, Arc<Sample>>,
+    pub voices:  Vec<Voice>,
+    pub ports:   JackPorts,
+}
+
 render!(Sampler = crate::view::sampler::render);
 handle!(Sampler = crate::control::sampler::handle);
+//jack!(Sampler {
+    //process = Sampler::process,
+    //audio = {
+        //ins  = |s|Ok(s.jack.audio_ins.values().collect()),
+        //outs = |s|Ok(s.jack.audio_outs.values().collect()),
+    //}
+    //midi = {
+        //ins  = |s|Ok(s.jack.midi_ins.values().collect()),
+        //outs = |s|Ok(s.jack.midi_outs.values().collect()),
+    //}
+//});
 process!(Sampler = Sampler::process);
 ports!(Sampler {
     audio: {
-        ins:  |s|Ok(s.audio_ins.iter().collect()),
-        outs: |s|Ok(s.audio_outs.iter().collect()),
+        ins:  |s|Ok(s.ports.audio_ins.values().collect()),
+        outs: |s|Ok(s.ports.audio_outs.values().collect()),
+    }
+    midi: {
+        ins:  |s|Ok(s.ports.midi_ins.values().collect()),
+        outs: |s|Ok(s.ports.midi_outs.values().collect()),
     }
-    midi: { ins: |s|Ok(vec![&s.midi_in]), }
 });
 
 impl Sampler {
     pub fn new (
         name: &str, samples: Option<BTreeMap<u7, Arc<Sample>>>,
-    ) -> Usually<Self> {
-        let (jack, _) = Client::new(name, ClientOptions::NO_START_SERVER)?;
-        Ok(Self {
-            name: name.into(),
-            cursor: (0, 0),
-            samples: samples.unwrap_or(BTreeMap::new()),
-            voices: vec![],
-            midi_in: jack.register_port("midi", MidiIn::default())?,
-            audio_ins: vec![
-                jack.register_port("recL", AudioIn::default())?,
-                jack.register_port("recR", AudioIn::default())?,
-            ],
-            audio_outs: vec![
-                jack.register_port("outL", AudioOut::default())?,
-                jack.register_port("outR", AudioOut::default())?,
-            ],
-            jack
-        })
+    ) -> Usually<Arc<Mutex<Box<dyn Device>>>> {
+        Jack::new(name)?
+            .register_midi_in("midi")?
+            .register_audio_in("recL")?
+            .register_audio_in("recR")?
+            .register_audio_out("outL")?
+            .register_audio_out("outR")?
+            .run(|ports|Box::new(Self {
+                name:    name.into(),
+                cursor:  (0, 0),
+                samples: samples.unwrap_or(BTreeMap::new()),
+                voices:  vec![],
+                ports
+            }))
     }
 
     pub fn process (&mut self, _: &Client, scope:  &ProcessScope) -> Control {
         // Output buffer: this will be copied to the audio outs.
-        let channel_count = self.audio_outs.len();
+        let channel_count = self.ports.audio_outs.len();
         let mut mixed = vec![vec![0.0;scope.n_frames() as usize];channel_count];
         // Process MIDI input to add new voices.
-        for RawMidi { time, bytes } in self.midi_in.iter(scope) {
+        for RawMidi { time, bytes } in self.ports.midi_ins.get("midi").unwrap().iter(scope) {
             if let LiveEvent::Midi { message, .. } = LiveEvent::parse(bytes).unwrap() {
                 if let MidiMessage::NoteOn { ref key, .. } = message {
                     if let Some(sample) = self.samples.get(key) {
@@ -130,7 +138,7 @@ impl Sampler {
             }
         }
         // Write output buffer to output ports.
-        for (i, port) in self.audio_outs.iter_mut().enumerate() {
+        for (i, port) in self.ports.audio_outs.values_mut().enumerate() {
             let buffer = &mixed[i];
             for (i, value) in port.as_mut_slice(scope).iter_mut().enumerate() {
                 *value = *buffer.get(i).unwrap_or(&0.0);

src/model/track.rs

@@ -18,7 +18,7 @@ pub struct Track {
     /// Red keys on piano roll.
     pub notes_on:   Vec<bool>,
     /// Device chain
-    pub devices:    Vec<Box<dyn Device>>,
+    pub devices:    Vec<Arc<Mutex<Box<dyn Device>>>>,
     /// Device selector
     pub device:     usize,
 }
@@ -27,8 +27,8 @@ impl Track {
     pub fn new (
         name:    &str,
         jack:    &Client,
-        devices: Option<Vec<Box<dyn Device>>>,
         phrases: Option<Vec<Phrase>>,
+        devices: Option<Vec<Arc<Mutex<Box<dyn Device>>>>>,
     ) -> Usually<Self> {
         Ok(Self {
             name:       name.to_string(),
@@ -43,17 +43,17 @@ impl Track {
             device:     0,
         })
     }
-    pub fn device (&self) -> Option<&Box<dyn Device>> {
-        self.devices.get(self.device)
+    pub fn device (&self, i: usize) -> Option<MutexGuard<Box<dyn Device>>> {
+        self.devices.get(i).map(|d|d.lock().unwrap())
     }
-    pub fn device_mut (&mut self) -> Option<&mut Box<dyn Device>> {
-        self.devices.get_mut(self.device)
+    pub fn active_device (&self) -> Option<MutexGuard<Box<dyn Device>>> {
+        self.device(self.device)
     }
-    pub fn first_device (&self) -> Option<&Box<dyn Device>> {
-        self.devices.get(0)
+    pub fn first_device (&self) -> Option<MutexGuard<Box<dyn Device>>> {
+        self.device(0)
     }
-    pub fn last_device (&self) -> Option<&Box<dyn Device>> {
-        self.devices.get(self.devices.len().saturating_sub(1))
+    pub fn last_device (&self) -> Option<MutexGuard<Box<dyn Device>>> {
+        self.device(self.devices.len().saturating_sub(1))
     }
     pub fn phrase (&self) -> Option<&Phrase> {
         if let Some(phrase) = self.sequence {

src/view/chain.rs

@@ -145,6 +145,7 @@ pub fn draw_as_column (
     let mut w = 0u16;
     let mut frames = vec![];
     for device in state.devices.iter() {
+        let device      = device.lock().unwrap();
         let style_midi  = Style::default().black().bold().on_green();
         let style_audio = Style::default().black().bold().on_red();
         let midi_ins    = device.midi_ins()?;