Handle device disconnect

src/service.rs

@@ -8,15 +8,30 @@ use service_specific::*;
 use shared::config::{Config, COMMAND_COUNT, COMMAND_PAUSE};
 
 fn main() -> Result<()> {
+    // azdelivery usart device
+    // let usb_device = UsbId {
+    //     vendor_id: 0x0403,
+    //     product_id: 0x6001,
+    // };
+
+    // default arduino uno device
+    let usb_device = UsbId {
+        vendor_id: 0x2341,
+        product_id: 0x0043,
+    };
+
     // create serial port
-    let mut port = Port::open(SerialPortSettings {
+    let mut port = Port::open(
+        usb_device,
+        SerialPortSettings {
             baud_rate: 57600,
             data_bits: DataBits::Eight,
             parity: Parity::None,
             stop_bits: StopBits::One,
             flow_control: FlowControl::None,
             timeout: Duration::from_millis(2500),
-    })?;
+        },
+    )?;
 
     let mut message_builder = MessageBuilder::default();
     let mut button_infos = [Duration::default(); COMMAND_COUNT];
@@ -24,10 +39,8 @@ fn main() -> Result<()> {
 
     // loop forever
     loop {
-        // check if port could be read
-        if let Ok(r) = port.read() {
         // handle incoming message
-            match r {
+        match port.read()? {
             SerialReadResult::Message(msg) => {
                 // create message out of stream
                 // discard remaining for now
@@ -47,7 +60,6 @@ fn main() -> Result<()> {
             SerialReadResult::Timeout => (),
         }
     }
-    }
 }
 
 fn execute_button_press(

src/service_specific/port.rs

@@ -19,13 +19,18 @@ pub struct SerialPortSettings {
     pub timeout: Duration,
 }
 
+pub struct UsbId {
+    pub vendor_id: u16,
+    pub product_id: u16,
+}
+
 pub struct Port {
     serial_port: Box<dyn SerialPort>,
 }
 
 impl Port {
-    pub fn open(settings: SerialPortSettings) -> Result<Self> {
-        let port_path = Self::find_macroboard()?;
+    pub fn open(usb_device: UsbId, settings: SerialPortSettings) -> Result<Self> {
+        let port_path = Self::loop_usb_devices(usb_device)?;
 
         let port = serialport::new(port_path, settings.baud_rate)
             .data_bits(settings.data_bits)
@@ -61,20 +66,29 @@ impl Port {
         Ok(())
     }
 
-    fn find_macroboard() -> Result<String> {
+    fn loop_usb_devices(usb_device: UsbId) -> Result<String> {
+        loop {
+            if let Some(device) = Self::find_macroboard(&usb_device)? {
+                return Ok(device);
+            }
+
+            std::thread::sleep(Duration::from_secs(2));
+        }
+    }
+
+    fn find_macroboard(usb_device: &UsbId) -> Result<Option<String>> {
         let available_ports = serialport::available_ports()
             .map_err(|err| anyhow!("error querying serial ports ( {})", err))?;
 
         for available_port in available_ports.iter() {
             if let serialport::SerialPortType::UsbPort(usb_info) = &available_port.port_type {
                 // check for the correct device
-                // if usb_info.vid == 0x0403 && usb_info.pid == 0x6001 {
-                if usb_info.vid == 0x2341 && usb_info.pid == 0x0043 {
-                    return Ok(available_port.port_name.clone());
+                if usb_info.vid == usb_device.vendor_id && usb_info.pid == usb_device.product_id {
+                    return Ok(Some(available_port.port_name.clone()));
                 }
             }
         }
 
-        return Err(anyhow!("macro board not found on usb bus".to_string()));
+        return Ok(None);
     }
 }