refactoring -> add error handling

smart-house/src/bin/mocks_example.rs

@@ -7,7 +7,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let dev = house.get_room_mut("Main").unwrap().get_device_mut("PSocA").unwrap();
     if let Device::PowerSocket(psoc) = dev {
-        psoc.set_on(!psoc.is_on());
+        psoc.set_on(!psoc.is_on().unwrap()).unwrap();
     }
 
     house.print_status();

smart-house/src/bin/power_socket_client.rs

@@ -10,7 +10,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     println!("{}", power_socket.display());
 
     std::thread::sleep(Duration::from_secs(2));
-    power_socket.set_on(!power_socket.is_on());
+    power_socket.set_on(!power_socket.is_on().unwrap()).unwrap();
 
     println!("{}", power_socket0.display());
     println!("{}", power_socket.display());

smart-house/src/bin/stubs_example.rs

@@ -60,7 +60,7 @@ fn switch_off_power_socket_in_hall_demo(house: &mut House) {
         println!("FAILED!");
         return;
     };
-    power_socket.set_on(false);
+    power_socket.set_on(false).unwrap();
     println!("SUCCESS");
     house.print_status();
 }

smart-house/src/house.rs

@@ -108,7 +108,7 @@ mod tests {
         let Device::PowerSocket(powers_socket) = house.get_room_mut("main").unwrap().get_device_mut("PSocA").unwrap() else {
             unreachable!()
         };
-        powers_socket.set_on(true);
+        powers_socket.set_on(true).unwrap();
 
         assert_eq!(
             format!("{}", house.get_room("main").unwrap().get_device("PSocA").unwrap().display()),

smart-house/src/power_socket.rs

@@ -1,6 +1,5 @@
 use std::cell::RefCell;
 use std::fmt::{Debug, Display};
-use std::io;
 use std::io::{Read, Write};
 use std::net::{SocketAddr, TcpStream};
 use std::time::Duration;
@@ -17,35 +16,50 @@ impl PowerSocket {
         }
     }
 
-    pub fn connect(addr: &str) -> Result<Self, io::Error> {
+    pub fn connect(addr: &str) -> Result<Self, std::io::Error> {
         let handle = PowerSocketClient::new(addr)?;
         Ok(Self { handle: Box::new(handle) })
     }
 
-    pub fn is_on(&self) -> bool {
+    pub fn is_on(&self) -> Result<bool, std::io::Error> {
         self.handle.is_on()
     }
 
-    pub fn set_on(&mut self, on: bool) {
+    pub fn set_on(&mut self, on: bool) -> Result<(), std::io::Error> {
         self.handle.set_on(on)
     }
 
-    pub fn get_power(&self) -> f32 {
+    pub fn get_power(&self) -> Result<f32, std::io::Error> {
         self.handle.get_power()
     }
 
     pub fn display(&self) -> impl Display {
-        let state = if self.is_on() { "ON" } else { "OFF" };
+        const ERR: &str = "PowerSocket[ ERR ]";
-        format!("PowerSocket[ {} : {:02.1} ]", state, self.get_power())
+        let power = match self.get_power() {
+            Ok(power) => power,
+            Err(e) => {
+                eprintln!("error on get power: {:?}", e);
+                return ERR.to_string();
+            }
+        };
+        let on = match self.is_on() {
+            Ok(state) => state,
+            Err(e) => {
+                eprintln!("error on get state: {:?}", e);
+                return ERR.to_string();
+            }
+        };
+        let state = if on { "ON" } else { "OFF" };
+        format!("PowerSocket[ {} : {:02.1} ]", state, power)
     }
 }
 
 trait PowerSocketHandle: Debug {
-    fn is_on(&self) -> bool;
+    fn is_on(&self) -> Result<bool, std::io::Error>;
 
-    fn set_on(&mut self, on: bool);
+    fn set_on(&mut self, on: bool) -> Result<(), std::io::Error>;
 
-    fn get_power(&self) -> f32;
+    fn get_power(&self) -> Result<f32, std::io::Error>;
 }
 
 #[derive(Debug)]
@@ -61,16 +75,17 @@ impl PowerSocketStub {
 }
 
 impl PowerSocketHandle for PowerSocketStub {
-    fn is_on(&self) -> bool {
+    fn is_on(&self) -> Result<bool, std::io::Error> {
-        self.on
+        Ok(self.on)
     }
 
-    fn set_on(&mut self, on: bool) {
+    fn set_on(&mut self, on: bool) -> Result<(), std::io::Error> {
-        self.on = on
+        self.on = on;
+        Ok(())
     }
 
-    fn get_power(&self) -> f32 {
+    fn get_power(&self) -> Result<f32, std::io::Error> {
-        if self.on { self.power_rate } else { 0.0 }
+        Ok(if self.on { self.power_rate } else { 0.0 })
     }
 }
 
@@ -82,8 +97,8 @@ struct PowerSocketClient {
 }
 
 impl PowerSocketClient {
-    fn new(addr: &str) -> Result<Self, io::Error> {
+    fn new(addr: &str) -> Result<Self, std::io::Error> {
-        let addr: SocketAddr = addr.parse().map_err(io::Error::other)?;
+        let addr: SocketAddr = addr.parse().map_err(std::io::Error::other)?;
         let stream = TcpStream::connect_timeout(&addr, TIMEOUT)?;
         stream.set_write_timeout(Some(TIMEOUT))?;
         stream.set_read_timeout(Some(TIMEOUT))?;
@@ -97,28 +112,44 @@ const CMD_TURN_OFF: u8 = 3;
 const CMD_GET_POWER: u8 = 4;
 
 impl PowerSocketHandle for PowerSocketClient {
-    fn is_on(&self) -> bool {
+    fn is_on(&self) -> Result<bool, std::io::Error> {
         let mut buf = [CMD_GET_ON; 1];
-        self.stream.borrow_mut().write_all(&buf).expect("CMD_GET_ON request should be sent");
+        self.stream
-        self.stream.borrow_mut().read_exact(&mut buf).expect("CMD_GET_ON response should be received");
+            .borrow_mut()
-        !matches!(buf, [0])
+            .write_all(&buf)
-    }
+            .map_err(|e| std::io::Error::other(format!("CMD_GET_ON request error: {:?}", e)))?;
-
-    fn set_on(&mut self, on: bool) {
-        let cmd = if on { CMD_TURN_ON } else { CMD_TURN_OFF };
-        let mut buf = [cmd; 1];
-        self.stream.borrow_mut().write_all(&buf).expect("change state request should be sent");
-        self.stream.borrow_mut().read_exact(&mut buf).expect("change state response should be received");
-    }
-
-    fn get_power(&self) -> f32 {
-        let mut buf = [CMD_GET_POWER; 4];
-        self.stream.borrow_mut().write_all(&buf[0..1]).expect("CMD_GET_POWER request should be sent");
         self.stream
             .borrow_mut()
             .read_exact(&mut buf)
-            .expect("CMD_GET_POWER response should be received");
+            .map_err(|e| std::io::Error::other(format!("CMD_GET_ON response error: {:?}", e)))?;
-        f32::from_le_bytes(buf)
+        Ok(!matches!(buf, [0]))
+    }
+
+    fn set_on(&mut self, on: bool) -> Result<(), std::io::Error> {
+        let cmd = if on { CMD_TURN_ON } else { CMD_TURN_OFF };
+        let mut buf = [cmd; 1];
+        self.stream
+            .borrow_mut()
+            .write_all(&buf)
+            .map_err(|e| std::io::Error::other(format!("change state request error: {:?}", e)))?;
+        self.stream
+            .borrow_mut()
+            .read_exact(&mut buf)
+            .map_err(|e| std::io::Error::other(format!("change state response error: {:?}", e)))?;
+        Ok(())
+    }
+
+    fn get_power(&self) -> Result<f32, std::io::Error> {
+        let mut buf = [CMD_GET_POWER; 4];
+        self.stream
+            .borrow_mut()
+            .write_all(&buf[0..1])
+            .map_err(|e| std::io::Error::other(format!("CMD_GET_POWER request error: {:?}", e)))?;
+        self.stream
+            .borrow_mut()
+            .read_exact(&mut buf)
+            .map_err(|e| std::io::Error::other(format!("CMD_GET_POWER response error: {:?}", e)))?;
+        Ok(f32::from_le_bytes(buf))
     }
 }
 
@@ -129,12 +160,12 @@ mod tests {
     #[test]
     fn smoke_test() {
         let mut power_socket = PowerSocket::stub(12.4, false);
-        assert!(!power_socket.is_on());
+        assert!(!power_socket.is_on().unwrap());
-        assert_eq!(power_socket.get_power(), 0.0);
+        assert_eq!(power_socket.get_power().unwrap(), 0.0);
 
-        power_socket.set_on(true);
+        power_socket.set_on(true).unwrap();
-        assert!(power_socket.is_on());
+        assert!(power_socket.is_on().unwrap());
-        assert_eq!(power_socket.get_power(), 12.4);
+        assert_eq!(power_socket.get_power().unwrap(), 12.4);
     }
 
     #[test]

smart-house/src/room.rs

@@ -70,7 +70,7 @@ mod tests {
         let Device::PowerSocket(power_socket) = room.get_device_mut("PSoc").unwrap() else {
             unreachable!()
         };
-        power_socket.set_on(true);
+        power_socket.set_on(true).unwrap();
 
         assert_eq!(format!("{}", room.get_device("PSoc").unwrap().display()), "DEV:PowerSocket[ ON : 12.3 ]");
         assert_eq!(format!("{}", room.get_device("Therm").unwrap().display()), "DEV:Thermometer[ 21.6 ]");
@@ -92,7 +92,7 @@ mod tests {
         let Some(Device::Thermometer(removed)) = room.remove_device("Therm") else {
             unreachable!()
         };
-        assert_eq!(removed.get_temperature(), 21.56);
+        assert_eq!(removed.get_temperature().unwrap(), 21.56);
         assert_eq!(room.devices.len(), 2);
     }
 }

smart-house/src/thermometer.rs

@@ -21,17 +21,24 @@ impl Thermometer {
         Ok(Self { handle: Box::new(handle) })
     }
 
-    pub fn get_temperature(&self) -> f32 {
+    pub fn get_temperature(&self) -> Result<f32, std::io::Error> {
         self.handle.get_temperature()
     }
 
     pub fn display(&self) -> impl Display {
-        format!("Thermometer[ {:02.1} ]", self.get_temperature())
+        let output = self.get_temperature();
+        match output {
+            Ok(v) => format!("Thermometer[ {:02.1} ]", v),
+            Err(e) => {
+                eprintln!("error fetching temperature: {:?}", e);
+                "Thermometer[ ERR ]".to_string()
+            }
+        }
     }
 }
 
 trait ThermometerHandle: Debug {
-    fn get_temperature(&self) -> f32;
+    fn get_temperature(&self) -> Result<f32, std::io::Error>;
 }
 
 #[derive(Debug)]
@@ -46,8 +53,8 @@ impl ThermometerHandleStub {
 }
 
 impl ThermometerHandle for ThermometerHandleStub {
-    fn get_temperature(&self) -> f32 {
+    fn get_temperature(&self) -> Result<f32, std::io::Error> {
-        self.temperature
+        Ok(self.temperature)
     }
 }
 
@@ -91,8 +98,8 @@ impl ThermometerClient {
 }
 
 impl ThermometerHandle for ThermometerClient {
-    fn get_temperature(&self) -> f32 {
+    fn get_temperature(&self) -> Result<f32, std::io::Error> {
-        f32::from_le_bytes(self.value.load(Ordering::Relaxed).to_le_bytes())
+        Ok(f32::from_le_bytes(self.value.load(Ordering::Relaxed).to_le_bytes()))
     }
 }
 
@@ -103,7 +110,7 @@ mod tests {
     #[test]
     fn smoke_test() {
         let thermometer = Thermometer::stub(20.0);
-        assert_eq!(thermometer.get_temperature(), 20.0);
+        assert_eq!(thermometer.get_temperature().unwrap(), 20.0);
     }
 
     #[test]