Update the error management of the temperatures mod

Try to remove the unwrap

src/fan/hysteresis.rs

@@ -1,5 +1,4 @@
 use crate::fan::Fan;
-use crate::temperatures::Temperatures;
 
 use rppal::gpio::{Gpio, OutputPin};
 
@@ -25,13 +24,11 @@ impl Hysteresis {
 }
 
 impl Fan for Hysteresis {
-    fn update_temperature(&mut self, temperatures: &Temperatures) {
-        if temperatures.cpu > self.max_temperature {
+    fn update_temperature(&mut self, temperature: f64) {
+        if temperature > self.max_temperature {
             self.pin.set_high();
-        } else {
-            if temperatures.cpu < self.max_temperature - self.hysteresis {
-                self.pin.set_low();
-            }
+        } else if temperature < self.max_temperature - self.hysteresis {
+            self.pin.set_low();
         }
     }
 

src/fan/mod.rs

@@ -1,9 +1,7 @@
 pub mod hysteresis;
 pub mod pwm;
 
-use crate::temperatures::Temperatures;
-
 pub trait Fan {
-    fn update_temperature(&mut self, _: &Temperatures);
+    fn update_temperature(&mut self, temperature: f64);
     fn percentage(&self) -> f64;
 }

src/fan/pwm.rs

@@ -1,5 +1,4 @@
 use crate::fan::Fan;
-use crate::temperatures::Temperatures;
 
 use rppal::pwm::{Channel, Polarity, Pwm as Pwm_rpi};
 
@@ -23,16 +22,16 @@ impl Pwm {
 }
 
 impl Fan for Pwm {
-    fn update_temperature(&mut self, temperatures: &Temperatures) {
-        let percentage = (temperatures.cpu - self.min_temperature)
-            / (self.max_temperature - self.min_temperature);
+    fn update_temperature(&mut self, temperature: f64) {
+        let percentage =
+            (temperature - self.min_temperature) / (self.max_temperature - self.min_temperature);
         let percentage = if percentage > 1_f64 {
             1_f64
         } else {
             percentage
         };
 
-        if temperatures.cpu > self.min_temperature {
+        if temperature > self.min_temperature {
             self.pwm.enable().unwrap();
             self.pwm.set_duty_cycle(percentage).unwrap();
         } else {

src/main.rs

@@ -6,11 +6,12 @@ use fan::pwm::Pwm;
 use fan::Fan;
 
 use rppal::pwm::Channel;
+use std::error::Error;
 use std::thread;
 use std::time::Duration;
 
-fn main() {
-    let mut temps = temperatures::Temperatures::default();
+fn main() -> Result<(), Box<dyn Error>> {
+    let mut temps = temperatures::Temperatures::new()?;
 
     let mut fan: Box<dyn Fan> = if true {
         Box::new(Hysteresis::new(52.0, 5.0, 18))
@@ -20,12 +21,21 @@ fn main() {
 
     loop {
         temps.update();
-        fan.update_temperature(&temps);
-        println!(
-            "CPU: {:.1}°C, fan is at {:.1}%",
-            temps.cpu,
-            fan.percentage() * 100_f64
-        );
+
+        match temps.max() {
+            Some(t) => {
+                fan.update_temperature(t);
+
+                println!(
+                    "CPU: {:.1}°C, fan is at {:.1}%",
+                    t,
+                    fan.percentage() * 100_f64
+                );
+            }
+            None => {
+                eprintln!("Recuring problem while getting the temperature");
+            }
+        }
 
         thread::sleep(Duration::from_secs(5));
     }

src/temperatures.rs

@@ -1,28 +1,45 @@
+use std::error::Error;
 use std::fs::File;
 use std::io::prelude::*;
 
 pub struct Temperatures {
-    pub cpu: f64,
+    cpu: f64,
+    cpu_error_count: i32,
 }
 
-impl Default for Temperatures {
-    fn default() -> Self {
-        Temperatures {
-            cpu: get_cpu_temp(),
+impl Temperatures {
+    pub fn new() -> Result<Self, Box<dyn Error>> {
+        Ok(Temperatures {
+            cpu: cpu()?,
+            cpu_error_count: 0,
+        })
+    }
+
+    pub fn update(&mut self) {
+        match cpu() {
+            Ok(t) => {
+                self.cpu = t;
+                self.cpu_error_count = 0;
+            }
+            Err(_) => {
+                self.cpu_error_count += 1;
+            }
+        }
+    }
+
+    pub fn max(&self) -> Option<f64> {
+        if self.cpu_error_count < 5 {
+            Some(self.cpu)
+        } else {
+            None
         }
     }
 }
 
-impl Temperatures {
-    pub fn update(&mut self) {
-        self.cpu = get_cpu_temp();
-    }
-}
-
-fn get_cpu_temp() -> f64 {
-    let mut f = File::open("/sys/class/thermal/thermal_zone0/temp").unwrap();
+fn cpu() -> Result<f64, Box<dyn Error>> {
+    let mut f = File::open("/sys/class/thermal/thermal_zone0/temp")?;
     let mut buffer = String::new();
-    f.read_to_string(&mut buffer).unwrap();
+    f.read_to_string(&mut buffer)?;
 
-    buffer.trim().parse::<f64>().unwrap() / 1_000_f64
+    Ok(buffer.trim().parse::<f64>()? / 1_000_f64)
 }