Expose errors

Cargo.lock

@@ -75,6 +75,7 @@ dependencies = [
 name = "localdeck-keyboard"
 version = "0.1.0"
 dependencies = [
+ "once_cell",
  "regex",
  "serialport",
 ]
@@ -105,6 +106,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.30"

Cargo.toml

@@ -4,5 +4,6 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+once_cell = "1.19.0"
 regex = "1.10.6"
 serialport = "4.5.1"

src/main.rs

@@ -1,10 +1,12 @@
+use once_cell::sync::Lazy;
 use regex::Regex;
 use serialport::{SerialPort, SerialPortInfo, SerialPortType};
-use std::io::{BufRead, BufReader};
+use std::io::{BufRead, BufReader, ErrorKind as IOErrorKind, Result as IOResult};
 use std::time::Duration;
 
 // My dev board - final might be different
 const VID_PID: (u16, u16) = (0x303a, 0x1001);
+static KEY_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"key '(?P<key>[A-Z])' pressed").unwrap());
 
 fn get_board_port() -> Option<SerialPortInfo> {
     let ports = serialport::available_ports().expect("No ports found!");
@@ -19,18 +21,23 @@ fn get_board_port() -> Option<SerialPortInfo> {
     None
 }
 
-fn get_keys(conn: Box<dyn SerialPort>) -> impl Iterator<Item = String> {
-    let reader = BufReader::new(conn);
-    let key_re = Regex::new(r"key '(?P<key>[A-Z])' pressed").unwrap();
-
-    reader.lines().filter_map(move |l| {
-        if let Ok(msg) = l {
-            return key_re
-                .captures(&msg)
+fn key_from_line(line: String) -> Option<String> {
+    KEY_RE
+        .captures(&line)
         .and_then(|captures| captures.name("key"))
-                .map(|k| String::from(k.as_str()));
+        .map(|k| String::from(k.as_str()))
 }
-        None
+
+fn get_keys(conn: Box<dyn SerialPort>) -> impl Iterator<Item = IOResult<String>> {
+    let reader = BufReader::new(conn);
+
+    reader.lines().filter_map(|l| match l {
+        // Discard timeouts
+        Err(e) if e.kind() == IOErrorKind::TimedOut => None,
+
+        Err(_) => Some(l),
+
+        Ok(s) => key_from_line(s).map(Ok),
     })
 }
 
@@ -49,7 +56,10 @@ fn main() {
         .open()
         .unwrap();
 
-    for key in get_keys(conn) {
-        println!("Key pressed: {}", key);
+    for maybe_key in get_keys(conn) {
+        match maybe_key {
+            Ok(key) => println!("Key pressed: {}", key),
+            Err(e) => println!("Error: {:?}", e),
+        }
     }
 }