Fine tune reading

macroboard.ino

@@ -65,7 +65,7 @@ void loop() {
   // debug
   Serial.println("test");
 
-  delay(1000);
+  delay(2000);
 }
 
 void check_pin(byte pin, byte index) {

src/port.rs

@@ -4,6 +4,7 @@ use serialport::prelude::*;
 use utilities::prelude::*;
 
 use std::cell::RefCell;
+use std::io;
 
 pub use serialport::{DataBits, FlowControl, Parity, SerialPortSettings, StopBits};
 pub use std::time::Duration;
@@ -33,13 +34,12 @@ impl Port {
     pub fn read(&self) -> VerboseResult<String> {
         let mut buf: Vec<u8> = (0..255).collect();
 
-        self.serial_port
-            .try_borrow_mut()?
-            .read(&mut buf[..])
-            .map_err(|err| format!("failed reading serial port ({})", err))?;
-
-        Ok(String::from_utf8(buf)
-            .map_err(|err| format!("failed converting utf8 buffer ({})", err))?)
+        match self.serial_port.try_borrow_mut()?.read(&mut buf[..]) {
+            Ok(t) => Ok(String::from_utf8(buf[0..t].to_vec())
+                .map_err(|err| format!("failed converting utf8 buffer ({})", err))?),
+            Err(ref e) if e.kind() == io::ErrorKind::TimedOut => Ok(String::new()),
+            Err(err) => create_error!(format!("failed reading serial port ({})", err)),
+        }
     }
 
     pub fn write(&self, msg: &str) -> VerboseResult<()> {

src/service.rs

@@ -17,8 +17,9 @@ fn main() -> VerboseResult<()> {
     let port = Port::open(settings)?;
 
     loop {
-        if let Ok(msg) = port.read() {
-            println!("{}", msg);
+        match port.read() {
+            Ok(msg) => println!("{}", msg),
+            Err(err) => println!("{}", err),
         }
     }
 }