Optional cell enhancements

libraries/tock-cells/src/optional_cell.rs

@@ -44,6 +44,20 @@ impl<T: Copy> OptionalCell<T> {
         self.value.set(None);
     }
 
+    /// Replace the contents with the value from the supplied `Option`,
+    /// or empty this `OptionalCell` if the supplied `Option` is `None`.
+    pub fn replace(&self, option: Option<T>) {
+        match option {
+            Some(v) => self.set(v),
+            None => self.clear(),
+        }
+    }
+
+    /// Returns the contained value, or panics if contents is `None`.
+    pub fn expect(&self, msg: &str) -> T {
+        self.value.get().expect(msg)
+    }
+
     /// Return the contained value and replace it with None.
     pub fn take(&self) -> Option<T> {
         self.value.take()
@@ -80,4 +94,10 @@ impl<T: Copy> OptionalCell<T> {
             .get()
             .map_or_else(default, |mut val| closure(&mut val))
     }
+
+    /// If the cell is empty, return `None`. Otherwise, call a closure
+    /// with the value of the cell and return the result.
+    pub fn and_then<U, F: FnOnce(T) -> Option<U>>(&self, f: F) -> Option<U> {
+        self.value.get().and_then(f)
+    }
 }