extract file source

src/gpu/mod.rs

@@ -1,8 +1,7 @@
 use crate::sensors::Memory;
+use crate::FileSource;
 use std::fmt::Write;
-use std::fs::{read_to_string, File};
-use std::io::{Read, Seek};
-use std::path::Path;
+use std::fs::read_to_string;
 use std::str::FromStr;
 use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::Mutex;
@@ -91,10 +90,6 @@ pub fn utilization() -> impl Iterator<Item = GpuUsage> {
 static GPU_POWER_UJ: AtomicU64 = AtomicU64::new(0);
 static GPU_POWER_LAST_READ: Mutex<Option<Instant>> = Mutex::new(None);
 
-fn read_gpu_power() -> Option<u64> {
-    read_num("/sys/class/drm/card0/device/hwmon/hwmon0/power1_average")
-}
-
 fn get_gpu_power_elapsed() -> Option<Duration> {
     let mut last_read = GPU_POWER_LAST_READ.lock().unwrap();
     let now = Instant::now();
@@ -104,14 +99,13 @@ fn get_gpu_power_elapsed() -> Option<Duration> {
 }
 
 pub fn update_gpu_power() {
-    let mut buff = String::with_capacity(16);
-    if let Ok(mut file) = File::open("/sys/class/drm/card0/device/hwmon/hwmon0/power1_average") {
+    if let Ok(mut file) =
+        FileSource::open("/sys/class/drm/card0/device/hwmon/hwmon0/power1_average")
+    {
         loop {
             if let Some(elapsed) = get_gpu_power_elapsed() {
-                buff.clear();
-                file.rewind().ok();
-                let current_power: u64 = match file.read_to_string(&mut buff) {
-                    Ok(_) => buff.trim().parse().unwrap_or_default(),
+                let current_power: u64 = match file.read() {
+                    Ok(current_power) => current_power,
                     Err(_) => {
                         return;
                     }

src/lib.rs

@@ -10,6 +10,10 @@ use crate::disk::*;
 use crate::sensors::*;
 use color_eyre::Result;
 use std::fmt::Write;
+use std::fs::File;
+use std::io::{ErrorKind, Read, Seek};
+use std::path::Path;
+use std::str::FromStr;
 
 pub fn get_metrics() -> Result<String> {
     let disk_usage = disk_usage()?;
@@ -115,3 +119,31 @@ pub fn get_metrics() -> Result<String> {
     }
     Ok(result)
 }
+
+pub struct FileSource {
+    buff: String,
+    file: File,
+}
+
+impl FileSource {
+    pub fn open<P: AsRef<Path>>(path: P) -> std::io::Result<FileSource> {
+        Ok(FileSource {
+            buff: String::with_capacity(32),
+            file: File::open(path)?,
+        })
+    }
+
+    pub fn read<T>(&mut self) -> std::io::Result<T>
+    where
+        T: FromStr,
+        <T as FromStr>::Err: std::error::Error + Send + Sync + 'static,
+    {
+        self.buff.clear();
+        self.file.rewind()?;
+        self.file.read_to_string(&mut self.buff)?;
+        self.buff
+            .trim()
+            .parse()
+            .map_err(|e| std::io::Error::new(ErrorKind::InvalidData, e))
+    }
+}