backlight: Add

src/widgets/backlight.rs

@@ -0,0 +1,69 @@
+use std::{
+    fs,
+    io::{ErrorKind, Error},
+    path::{Path, PathBuf},
+};
+
+use crate::{
+    color::Color,
+    widgets::bar_widget::{
+        BarWidget,
+        BarWidgetImpl,
+    },
+};
+
+fn read_file_as_u64(path: &Path) -> Result<u64, Error> {
+    let mut s = fs::read_to_string(path)?;
+    s.pop();
+    s.parse::<u64>()
+        .map_err(|_e| Error::new(ErrorKind::Other, "unable to parse value"))
+}
+
+pub struct Backlight {
+    device_path: PathBuf,
+    cur: u64,
+    max: u64,
+    dirty: bool,
+}
+
+impl Backlight {
+    fn update(&mut self) {
+        self.cur = read_file_as_u64(self.device_path.join("brightness").as_path()).unwrap();
+        self.max = read_file_as_u64(self.device_path.join("max_brightness").as_path()).unwrap();
+    }
+
+    pub fn new(path: &str) -> BarWidget {
+        let mut dev = Backlight{
+            device_path: Path::new("/sys/class/backlight").to_path_buf().join(path),
+            cur: 0,
+            max: 0,
+            dirty: false,
+        };
+
+        dev.update();
+        BarWidget::new(Box::new(dev))
+    }
+}
+
+impl BarWidgetImpl for Backlight {
+    fn get_dirty(&self) -> bool {
+        self.dirty
+    }
+    fn set_dirty(&mut self, dirty: bool) {
+        self.dirty = dirty
+    }
+    fn name(&self) -> &'static str {
+        "backlight"
+    }
+    fn value(&self) -> f32 {
+        if self.cur > self.max {
+            // what.
+            return 1.0;
+        }
+
+        self.cur as f32 / self.max as f32
+    }
+    fn color(&self) -> Color {
+        Color::new(1.0, 1.0, 1.0, 1.0)
+    }
+}

src/widgets/mod.rs

@@ -1,5 +1,6 @@
 mod bar_widget;
 mod battery;
+mod backlight;
 mod clock;
 mod date;
 mod launcher;
@@ -7,6 +8,7 @@ mod line;
 mod widget;
 
 pub use battery::Battery;
+pub use backlight::Backlight;
 pub use clock::Clock;
 pub use date::Date;
 pub use launcher::Interface;