Better error handling

src/main.rs

@@ -1,7 +1,10 @@
 use std::fs::File;
 use std::io::Write;
+use std::io::Result;
+use std::process::Command;
 use std::time::{Duration, Instant};
 use std::thread::sleep;
+
 use evdev_rs::Device;
 use evdev_rs::InputEvent;
 use evdev_rs::ReadFlag;
@@ -9,7 +12,7 @@ use evdev_rs::enums::EventCode;
 use evdev_rs::enums::EV_KEY;
 
 #[derive(Default)]
-struct Controller {
+struct ControllerState {
     power: u8,
     brake: u8,
     button_sl: bool,
@@ -31,58 +34,67 @@ enum ControllerModel {
     TYPE2,
 }
 
-fn main() {
-    let d1 = Device::new_from_path("/dev/input/event1").unwrap();
-    let d2 = Device::new_from_path("/dev/input/event2").unwrap();
+fn main() -> Result<()> {
+    let d1 = Device::new_from_path("/dev/input/event1");
+    let d2 = Device::new_from_path("/dev/input/event2");
 
-    let mut controller: Controller = Default::default();
-    let mut controller_model: ControllerModel = ControllerModel::NONE;
+    match (d1, d2) {
+        (Ok(d1), Ok(d2)) => {
+            let mut controller_state: ControllerState = Default::default();
+            let mut controller_model: ControllerModel = ControllerModel::NONE;
+        
+            // Save current time and 5 seconds in the future to check for pressed buttons later
+            let start_time = Instant::now();
+            let init_time = start_time + Duration::from_secs(5);
+        
+            // Turn on door light to indicate selection mode 
+            set_lamp(true);
+            println!("Hold a button to select the controller model...");
 
-    // Save current time and 5 seconds in the future to check for pressed buttons later
-    let start_time = Instant::now();
-    let init_time = start_time + Duration::from_secs(5);
+            loop {
+                // Process events from both input devices
+                for device in [&d1, &d2] {
+                    let ev = device.next_event(ReadFlag::NORMAL);
+                    match ev {
+                        Ok(ev) => read_input(ev.1, &mut controller_state),
+                        Err(_e) => (),
+                    }
+                }
+        
+                // If init time has passed, try to select model or quit
+                if controller_model == ControllerModel::NONE && Instant::now() >= init_time {
+                    if controller_state.button_right {
+                        controller_model = ControllerModel::DGOC44U;
+                        println!("Selected controller DGOC44-U, starting gadget...");
+                    }
+                    else if controller_state.button_left {
+                        controller_model = ControllerModel::TYPE2;
+                        println!("Selected controller TCPP-20009, starting gadget...");
+                    }
+                    else
+                    {
+                        // Turn off door light and quit
+                        set_lamp(false);
+                        println!("No controller selected, exiting...");
+                        break;
+                    }
+                    // Turn off door light and vibrate to end selection mode
+                    set_lamp(false);
+                    set_rumble(true);
+                    sleep(Duration::from_millis(500));
+                    set_rumble(false);
 
-    // Turn on door light to indicate selection mode 
-    set_door(true);
-    println!("Hold a button to select the controller model...");
-
-    loop {
-        // Process events from both input devices
-        for device in [&d1, &d2] {
-            let ev = device.next_event(ReadFlag::NORMAL).map(|val| val.1);
-            match ev {
-                Ok(ev) => read_input(ev, &mut controller),
-                Err(_e) => (),
+                    // Stop main game
+                    stop_game();
+                }
             }
-        }
-
-        // If init time has passed, try to select model or quit
-        if controller_model == ControllerModel::NONE && Instant::now() >= init_time {
-            if controller.button_right {
-                controller_model = ControllerModel::DGOC44U;
-                println!("Selected controller DGOC44-U, starting gadget...");
-            }
-            else if controller.button_left {
-                controller_model = ControllerModel::TYPE2;
-                println!("Selected controller TCPP-20009, starting gadget...");
-            }
-            else
-            {
-                // Turn off door light and quit
-                set_door(false);
-                println!("No controller selected, exiting...");
-                break;
-            }
-            // Turn off door light and vibrate to end selection mode
-            set_door(false);
-            set_rumble(true);
-            sleep(Duration::from_millis(500));
-            set_rumble(false);
-        }
+        },
+        _ => println!("ERROR: Could not read input devices! Stopping..."),
     }
+    Ok(())
 }
 
-fn read_input(event: InputEvent, controller: &mut Controller) {
+fn read_input(event: InputEvent, controller: &mut ControllerState) {
     // Save input status to object for easier processing
     match event.event_code{
         EventCode::EV_KEY(EV_KEY::KEY_0)=>if event.value == 1 {controller.power = 0},
@@ -115,14 +127,24 @@ fn read_input(event: InputEvent, controller: &mut Controller) {
     }
 }
 
-fn set_door(status: bool) -> std::io::Result<()> {
-    let mut out = File::create("/sys/class/leds/led2/brightness")?;
-    out.write(if status {b"1"} else {b"0"})?;
-    Ok(())
+fn set_lamp(status: bool) {
+    if let Ok(mut out) = File::create("/sys/class/leds/led2/brightness") {
+        out.write(if status {b"1"} else {b"0"}).ok(); 
+    }
+    else {
+        println!("WARNING: Could not set door lamp status!")
+    }
 }
 
-fn set_rumble(status: bool) -> std::io::Result<()> {
-    let mut out = File::create("/sys/class/leds/led1/brightness")?;
-    out.write(if status {b"1"} else {b"0"})?;
-    Ok(())
+fn set_rumble(status: bool) {
+    if let Ok(mut out) = File::create("/sys/class/leds/led1/brightness") {
+        out.write(if status {b"1"} else {b"0"}).ok(); 
+    }
+    else {
+        println!("WARNING: Could not set rumble motor status!")
+    }
 }
+
+fn stop_game() {
+    Command::new("/etc/init.d/S99dgtype3").arg("stop").output().ok();
+}