42 lines
1.1 KiB
Rust
42 lines
1.1 KiB
Rust
|
use std::{
|
||
|
|
fs::{self, File},
|
||
|
|
io::{self, Read},
|
||
|
|
path::PathBuf,
|
||
|
|
str::FromStr,
|
||
|
|
};
|
||
|
|
|
||
|
|
struct Backlight(PathBuf);
|
||
|
|
|
||
|
|
impl Backlight {
|
||
|
|
fn brightness(&self) -> Option<i64> {
|
||
|
|
self.prop("brightness")
|
||
|
|
}
|
||
|
|
|
||
|
|
fn max_brightness(&self) -> Option<i64> {
|
||
|
|
self.prop("max_brightness")
|
||
|
|
}
|
||
|
|
|
||
|
|
fn prop<T: FromStr>(&self, name: &str) -> Option<T> {
|
||
|
|
let mut file = File::open(&self.0.join(name)).ok()?;
|
||
|
|
let mut s = String::new();
|
||
|
|
file.read_to_string(&mut s).ok()?;
|
||
|
|
s.parse().ok()
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Choose backlight with most "precision". This is what `light` does.
|
||
|
|
fn backlight() -> io::Result<Option<Backlight>> {
|
||
|
|
let mut best_backlight = None;
|
||
|
|
let mut best_max_brightness = 0;
|
||
|
|
for i in fs::read_dir("/sys/class/backlight")? {
|
||
|
|
let backlight = Backlight(i?.path());
|
||
|
|
if let Some(max_brightness) = backlight.max_brightness() {
|
||
|
|
if max_brightness > best_max_brightness {
|
||
|
|
best_backlight = Some(backlight);
|
||
|
|
best_max_brightness = max_brightness;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
Ok(best_backlight)
|
||
|
|
}
|