nuke spin_sleep dependency

We were only using it for one single function. We can simply copy that
function into the codebase and be done with it. With the added benefit
of constifying the accuracy duration value.

daemon/Cargo.toml

@@ -13,7 +13,6 @@ rustix = { version = "0.38", default-features = false, features = [ "event" ] }
 libc = "0.2"
 
 keyframe = "1.1"
-spin_sleep = "1.2"
 
 sd-notify = { version = "0.4.1" }
 

daemon/src/animations/mod.rs

@@ -168,7 +168,7 @@ impl Animator {
 
                     crate::wallpaper::attach_buffers_and_damange_surfaces(&wallpapers);
                     let timeout = duration.saturating_sub(now.elapsed());
-                    spin_sleep::sleep(timeout);
+                    crate::spin_sleep(timeout);
                     crate::wallpaper::commit_wallpapers(&wallpapers);
 
                     now = std::time::Instant::now();

daemon/src/animations/transitions.rs

@@ -92,7 +92,7 @@ impl<'a> Transition<'a> {
         }
         crate::wallpaper::attach_buffers_and_damange_surfaces(self.wallpapers);
         let timeout = self.fps.saturating_sub(now.elapsed());
-        spin_sleep::sleep(timeout);
+        crate::spin_sleep(timeout);
         crate::wallpaper::commit_wallpapers(self.wallpapers);
         *now = Instant::now();
     }

daemon/src/main.rs

@@ -663,3 +663,19 @@ pub fn is_daemon_running(addr: &PathBuf) -> Result<bool, String> {
         _ => Err("Daemon did not return Answer::Ping, as expected".to_string()),
     }
 }
+
+/// copy-pasted from the `spin_sleep` crate on crates.io
+///
+/// This will sleep for an amount of time we can roughly expected the OS to still be precise enough
+/// for frame timing (125 us, currently).
+fn spin_sleep(duration: std::time::Duration) {
+    const ACCURACY: std::time::Duration = std::time::Duration::new(0, 125_000);
+    let start = std::time::Instant::now();
+    if duration > ACCURACY {
+        std::thread::sleep(duration - ACCURACY);
+    }
+
+    while start.elapsed() < duration {
+        std::thread::yield_now();
+    }
+}