Update touchbar active layer in real time as conf is modified

src/main.rs

@@ -1,10 +1,11 @@
 use std::{
-    fs::{File, OpenOptions, read_to_string},
+    fs::{File, OpenOptions, read_to_string, self},
     os::{
         fd::AsRawFd,
         unix::{io::OwnedFd, fs::OpenOptionsExt}
     },
     path::Path,
+    time::SystemTime,
     collections::HashMap,
     cmp::min,
     mem,
@@ -343,6 +344,13 @@ fn load_config() -> Config {
     }
 }
 
+fn get_file_modified_time(path: &str) -> Option<SystemTime> {
+    fs::metadata(path)
+        .ok()
+        .map(|metadata| metadata.modified().ok())
+        .flatten()
+}
+
 fn main() {
     let mut drm = DrmBackend::open_card().unwrap();
     let _ = panic::catch_unwind(AssertUnwindSafe(|| {
@@ -398,6 +406,8 @@ fn real_main(drm: &mut DrmBackend) {
     let pollfd_tb = PollFd::new(&fd_tb, PollFlags::POLLIN);
     let pollfd_main = PollFd::new(&fd_main, PollFlags::POLLIN);
     uinput.set_evbit(EventKind::Key).unwrap();
+    let config_path = "/etc/tiny-dfr/config.toml";
+    let mut last_modified_time = get_file_modified_time(config_path);
     let mut layers = mem::take(&mut cfg.layers);
     for layer in &layers {
         for button in &layer.buttons {
@@ -424,6 +434,15 @@ fn real_main(drm: &mut DrmBackend) {
     let mut digitizer: Option<InputDevice> = None;
     let mut touches = HashMap::new();
     loop {
+        let current_modified_time = get_file_modified_time(config_path);
+        if current_modified_time != last_modified_time {
+            cfg = load_config();
+            layers = mem::take(&mut cfg.layers);
+            active_layer = 0;
+            last_modified_time = current_modified_time;
+            needs_complete_redraw = true;
+        }
+
         let mut next_timeout_ms = TIMEOUT_MS;
 
         if cfg.enable_pixel_shift {