cpu&power: share fs impls

src/cpu.rs

@@ -1,33 +1,9 @@
 use anyhow::{Context, bail};
 use yansi::Paint as _;
 
-use std::{fmt, fs, path::Path, string::ToString};
+use std::{fmt, string::ToString};
 
-fn exists(path: impl AsRef<Path>) -> bool {
-    let path = path.as_ref();
-
-    path.exists()
-}
-
-// Not doing any anyhow stuff here as all the calls of this ignore errors.
-fn read_u64(path: impl AsRef<Path>) -> anyhow::Result<u64> {
-    let path = path.as_ref();
-
-    let content = fs::read_to_string(path)?;
-
-    Ok(content.trim().parse()?)
-}
-
-fn write(path: impl AsRef<Path>, value: &str) -> anyhow::Result<()> {
-    let path = path.as_ref();
-
-    fs::write(path, value).with_context(|| {
-        format!(
-            "failed to write '{value}' to '{path}'",
-            path = path.display(),
-        )
-    })
-}
+use crate::fs;
 
 #[derive(Debug, Clone, Copy)]
 pub struct Cpu {
@@ -96,11 +72,11 @@ impl Cpu {
     pub fn rescan(&mut self) -> anyhow::Result<()> {
         let Self { number, .. } = self;
 
-        if !exists(format!("/sys/devices/system/cpu/cpu{number}")) {
+        if !fs::exists(format!("/sys/devices/system/cpu/cpu{number}")) {
             bail!("{self} does not exist");
         }
 
-        let has_cpufreq = exists(format!("/sys/devices/system/cpu/cpu{number}/cpufreq"));
+        let has_cpufreq = fs::exists(format!("/sys/devices/system/cpu/cpu{number}/cpufreq"));
 
         self.has_cpufreq = has_cpufreq;
 
@@ -110,7 +86,7 @@ impl Cpu {
     pub fn get_available_governors(&self) -> Vec<String> {
         let Self { number, .. } = self;
 
-        let Ok(content) = fs::read_to_string(format!(
+        let Ok(Some(content)) = fs::read(format!(
             "/sys/devices/system/cpu/cpu{number}/cpufreq/scaling_available_governors"
         )) else {
             return Vec::new();
@@ -137,7 +113,7 @@ impl Cpu {
             );
         }
 
-        write(
+        fs::write(
             format!("/sys/devices/system/cpu/cpu{number}/cpufreq/scaling_governor"),
             governor,
         )
@@ -151,7 +127,7 @@ impl Cpu {
     pub fn get_available_epps(&self) -> Vec<String> {
         let Self { number, .. } = self;
 
-        let Ok(content) = fs::read_to_string(format!(
+        let Ok(Some(content)) = fs::read(format!(
             "/sys/devices/system/cpu/cpu{number}/cpufreq/energy_performance_available_preferences"
         )) else {
             return Vec::new();
@@ -175,7 +151,7 @@ impl Cpu {
             );
         }
 
-        write(
+        fs::write(
             format!("/sys/devices/system/cpu/cpu{number}/cpufreq/energy_performance_preference"),
             epp,
         )
@@ -226,7 +202,7 @@ impl Cpu {
             );
         }
 
-        write(
+        fs::write(
             format!("/sys/devices/system/cpu/cpu{number}/cpufreq/energy_performance_bias"),
             epb,
         )
@@ -244,7 +220,7 @@ impl Cpu {
         let frequency_khz = frequency_mhz * 1000;
         let frequency_khz = frequency_khz.to_string();
 
-        write(
+        fs::write(
             format!("/sys/devices/system/cpu/cpu{number}/cpufreq/scaling_min_freq"),
             &frequency_khz,
         )
@@ -256,7 +232,7 @@ impl Cpu {
     fn validate_frequency_minimum(&self, new_frequency_mhz: u64) -> anyhow::Result<()> {
         let Self { number, .. } = self;
 
-        let Ok(minimum_frequency_khz) = read_u64(format!(
+        let Ok(minimum_frequency_khz) = fs::read_u64(format!(
             "/sys/devices/system/cpu/cpu{number}/cpufreq/scaling_min_freq"
         )) else {
             // Just let it pass if we can't find anything.
@@ -282,7 +258,7 @@ impl Cpu {
         let frequency_khz = frequency_mhz * 1000;
         let frequency_khz = frequency_khz.to_string();
 
-        write(
+        fs::write(
             format!("/sys/devices/system/cpu/cpu{number}/cpufreq/scaling_max_freq"),
             &frequency_khz,
         )
@@ -294,7 +270,7 @@ impl Cpu {
     fn validate_frequency_maximum(&self, new_frequency_mhz: u64) -> anyhow::Result<()> {
         let Self { number, .. } = self;
 
-        let Ok(maximum_frequency_khz) = read_u64(format!(
+        let Ok(maximum_frequency_khz) = fs::read_u64(format!(
             "/sys/devices/system/cpu/cpu{number}/cpufreq/scaling_min_freq"
         )) else {
             // Just let it pass if we can't find anything.
@@ -331,16 +307,16 @@ impl Cpu {
         let generic_boost_path = "/sys/devices/system/cpu/cpufreq/boost";
 
         // Try each boost control path in order of specificity
-        if write(intel_boost_path_negated, value_boost_negated).is_ok() {
+        if fs::write(intel_boost_path_negated, value_boost_negated).is_ok() {
             return Ok(());
         }
-        if write(amd_boost_path, value_boost).is_ok() {
+        if fs::write(amd_boost_path, value_boost).is_ok() {
             return Ok(());
         }
-        if write(msr_boost_path, value_boost).is_ok() {
+        if fs::write(msr_boost_path, value_boost).is_ok() {
             return Ok(());
         }
-        if write(generic_boost_path, value_boost).is_ok() {
+        if fs::write(generic_boost_path, value_boost).is_ok() {
             return Ok(());
         }
 
@@ -348,7 +324,7 @@ impl Cpu {
         if Self::all()?.iter().any(|cpu| {
             let Cpu { number, .. } = cpu;
 
-            write(
+            fs::write(
                 format!("/sys/devices/system/cpu/cpu{number}/cpufreq/boost"),
                 value_boost,
             )

src/fs.rs

@@ -0,0 +1,55 @@
+use std::{fs, io, path::Path};
+
+use anyhow::Context;
+
+pub fn exists(path: impl AsRef<Path>) -> bool {
+    let path = path.as_ref();
+
+    path.exists()
+}
+
+pub fn read_dir(path: impl AsRef<Path>) -> anyhow::Result<fs::ReadDir> {
+    let path = path.as_ref();
+
+    fs::read_dir(path)
+        .with_context(|| format!("failed to read directory '{path}'", path = path.display()))
+}
+
+pub fn read(path: impl AsRef<Path>) -> anyhow::Result<Option<String>> {
+    let path = path.as_ref();
+
+    match fs::read_to_string(path) {
+        Ok(string) => Ok(Some(string)),
+
+        Err(error) if error.kind() == io::ErrorKind::NotFound => Ok(None),
+
+        Err(error) => {
+            Err(error).with_context(|| format!("failed to read '{path}", path = path.display()))
+        }
+    }
+}
+
+pub fn read_u64(path: impl AsRef<Path>) -> anyhow::Result<u64> {
+    let path = path.as_ref();
+
+    let content = fs::read_to_string(path)
+        .with_context(|| format!("failed to read '{path}'", path = path.display()))?;
+
+    Ok(content.trim().parse().with_context(|| {
+        format!(
+            "failed to parse contents of '{path}' as a unsigned number",
+            path = path.display(),
+        )
+    })?)
+}
+
+pub fn write(path: impl AsRef<Path>, value: &str) -> anyhow::Result<()> {
+    let path = path.as_ref();
+
+    fs::write(path, value).with_context(|| {
+        format!(
+            "failed to write '{value}' to '{path}'",
+            path = path.display(),
+        )
+    })
+}

src/main.rs

@@ -1,10 +1,14 @@
+mod cpu;
+mod power_supply;
+mod system;
+
+mod fs;
+
 mod config;
 // mod core;
-mod cpu;
 mod daemon;
 // mod engine;
 // mod monitor;
-mod power_supply;
 
 use anyhow::Context;
 use clap::Parser as _;

src/power_supply.rs

@@ -1,22 +1,12 @@
-use anyhow::{Context, bail};
+use anyhow::{Context, anyhow, bail};
 use yansi::Paint as _;
 
 use std::{
-    fmt, fs,
+    fmt,
     path::{Path, PathBuf},
 };
 
-// TODO: Migrate to central utils file. Same exists in cpu.rs.
-fn write(path: impl AsRef<Path>, value: &str) -> anyhow::Result<()> {
-    let path = path.as_ref();
-
-    fs::write(path, value).with_context(|| {
-        format!(
-            "failed to write '{value}' to '{path}'",
-            path = path.display(),
-        )
-    })
-}
+use crate::fs;
 
 /// Represents a pattern of path suffixes used to control charge thresholds
 /// for different device vendors.
@@ -136,10 +126,10 @@ impl PowerSupply {
     fn get_type(&self) -> anyhow::Result<String> {
         let type_path = self.path.join("type");
 
-        let type_ = fs::read_to_string(&type_path)
+        let type_ = fs::read(&type_path)
             .with_context(|| format!("failed to read '{path}'", path = type_path.display()))?;
 
-        Ok(type_)
+        type_.ok_or_else(|| anyhow!("'{path}' doesn't exist", path = type_path.display()))
     }
 
     pub fn rescan(&mut self) -> anyhow::Result<()> {
@@ -180,9 +170,9 @@ impl PowerSupply {
     }
 
     pub fn set_charge_threshold_start(&self, charge_threshold_start: u8) -> anyhow::Result<()> {
-        write(
+        fs::write(
             &self.charge_threshold_path_start().ok_or_else(|| {
-                anyhow::anyhow!(
+                anyhow!(
                     "power supply '{name}' does not support changing charge threshold levels",
                     name = self.name,
                 )
@@ -197,9 +187,9 @@ impl PowerSupply {
     }
 
     pub fn set_charge_threshold_end(&self, charge_threshold_end: u8) -> anyhow::Result<()> {
-        write(
+        fs::write(
             &self.charge_threshold_path_end().ok_or_else(|| {
-                anyhow::anyhow!(
+                anyhow!(
                     "power supply '{name}' does not support changing charge threshold levels",
                     name = self.name,
                 )
@@ -216,7 +206,7 @@ impl PowerSupply {
     pub fn get_available_platform_profiles() -> Vec<String> {
         let path = "/sys/firmware/acpi/platform_profile_choices";
 
-        let Ok(content) = fs::read_to_string(path) else {
+        let Ok(Some(content)) = fs::read(path) else {
             return Vec::new();
         };
 
@@ -245,7 +235,7 @@ impl PowerSupply {
             );
         }
 
-        write("/sys/firmware/acpi/platform_profile", profile)
+        fs::write("/sys/firmware/acpi/platform_profile", profile)
             .context("this probably means that your system does not support changing ACPI profiles")
     }
 }

src/system.rs

@@ -0,0 +1,14 @@
+pub struct System {
+    pub is_desktop: bool,
+}
+
+impl System {
+    pub fn new() -> anyhow::Result<Self> {
+        let mut system = Self { is_desktop: false };
+        system.rescan()?;
+
+        Ok(system)
+    }
+
+    pub fn rescan(&mut self) -> anyhow::Result<()> {}
+}