Fix embassy-time wasm build and fix a bug in wasm time driver

1 files changed, 12 insertions, 6 deletions

diff --git a/embassy-time/src/driver_wasm.rs b/embassy-time/src/driver_wasm.rs
index d7a6b0d8d..63d049897 100644
--- a/embassy-time/src/driver_wasm.rs
+++ b/embassy-time/src/driver_wasm.rs
@@ -81,26 +81,32 @@ impl Driver for TimeDriver {
         }
     }
 
-    fn set_alarm_callback(&self, alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) -> bool {
+    fn set_alarm_callback(&self, alarm: AlarmHandle, callback: fn(*mut ()), ctx: *mut ()) {
         self.init();
         let mut alarms = unsafe { self.alarms.as_ref() }.lock().unwrap();
         let alarm = &mut alarms[alarm.id() as usize];
         alarm.closure.replace(Closure::new(move || {
             callback(ctx);
         }));
-
-        true
     }
 
-    fn set_alarm(&self, alarm: AlarmHandle, timestamp: u64) {
+    fn set_alarm(&self, alarm: AlarmHandle, timestamp: u64) -> bool {
         self.init();
         let mut alarms = unsafe { self.alarms.as_ref() }.lock().unwrap();
         let alarm = &mut alarms[alarm.id() as usize];
-        let timeout = (timestamp - self.now()) as u32;
         if let Some(token) = alarm.token {
             clearTimeout(token);
         }
-        alarm.token = Some(setTimeout(alarm.closure.as_ref().unwrap(), timeout / 1000));
+
+        let now = self.now();
+        if timestamp <= now {
+            false
+        } else {
+            let timeout = (timestamp - now) as u32;
+            alarm.token = Some(setTimeout(alarm.closure.as_ref().unwrap(), timeout / 1000));
+
+            true
+        }
     }
 }