Add a standalone cli arg to connect JACK inputs

src/wrapper/standalone/backend/jack.rs

@@ -125,7 +125,25 @@ impl Jack {
             outputs.push(port);
         }
 
-        // TODO: Command line argument to connect the inputs?
+        // This option can either be set to a single port all inputs should be connected to, or a
+        // comma separated list of ports
+        if let Some(port_name) = config.connect_jack_inputs {
+            if port_name.contains(',') {
+                for (port_name, input) in port_name.split(',').zip(&inputs) {
+                    if let Err(err) = client.connect_ports_by_name(port_name, &input.name()?) {
+                        nih_error!("Could not connect to '{port_name}': {err}");
+                        break;
+                    }
+                }
+            } else {
+                for input in &inputs {
+                    if let Err(err) = client.connect_ports_by_name(&port_name, &input.name()?) {
+                        nih_error!("Could not connect to '{port_name}': {err}");
+                        break;
+                    }
+                }
+            }
+        }
 
         Ok(Self {
             client: Some(client),

src/wrapper/standalone/config.rs

@@ -28,6 +28,15 @@ pub struct WrapperConfig {
     #[clap(value_parser, short = 'p', long, default_value = "512")]
     pub period_size: u32,
 
+    /// If set to a port name ('foo:bar_1'), then all all inputs will be connected to that port. If
+    /// the option is set to a comma separated list of port names ('foo:bar_1,foo:bar_2') then the
+    /// input ports will be connected in that order. No inputs will be connected if the port option
+    /// is not set.
+    ///
+    /// This option is only used with the JACK backend.
+    #[clap(value_parser, long)]
+    pub connect_jack_inputs: Option<String>,
+
     /// The editor's DPI scaling factor.
     ///
     /// This option is ignored on macOS.