popover: Use thread-safe reference

This reference will be modified from the screensaver thread.

src/actors/popover.rs

@@ -11,16 +11,21 @@ but it cannot get the user-selected overlay, because it's stored in state.
 To solve this, overlay will be cached in the popover actor,
 and updated by main state every time it changes.
 */
+use crate::logging;
+use std::borrow::BorrowMut;
 use super::Destination;
 
 pub mod c {
     use super::*;
-    use crate::util::c::Wrapped;
-    /// The mutable instance of state
-    pub type Actor = Wrapped<State>;
+    use crate::util::c::ArcWrapped;
+    /// The mutable instance of state.
+    /// Thread-safe because this actor does not get its own event loop,
+    /// and therefore can't have a channel to receive messages,
+    /// so instead messages will be passed directly to the mutexed actor.
+    pub type Actor = ArcWrapped<State>;
     /// It's the same because the state is a simple mutex-protected type.
     /// There are no channels involved.
-    pub type Destination = Wrapped<State>;
+    pub type Destination = ArcWrapped<State>;
 }
 
 pub enum Event {
@@ -32,8 +37,18 @@ impl Destination for c::Destination {
     type Event = Event;
     fn send(&self, event: Self::Event) {
         let actor = self.clone_ref();
-        let mut actor = actor.borrow_mut();
-        *actor = actor.clone().handle_event(event);
+        let actor = actor.lock();
+        match actor {
+            Ok(mut actor) => {
+                let actor = actor.borrow_mut();
+                **actor = actor.clone().handle_event(event);
+            },
+            Err(e) => log_print!(
+                logging::Level::Bug,
+                "Cannot lock popover state: {:?}",
+                e,
+            ),
+        }
     }
 }
 

src/main.rs

@@ -30,7 +30,7 @@ mod c {
     use crate::outputs::Outputs;
     use crate::state;
     use crate::submission::Submission;
-    use crate::util::c::Wrapped;
+    use crate::util::c::{ArcWrapped, Wrapped};
     use crate::vkeyboard::c::ZwpVirtualKeyboardV1;
     
     /// DbusHandler*
@@ -132,7 +132,7 @@ mod c {
             state_manager: Wrapped::new(state_manager),
             receiver: Wrapped::new(receiver),
             wayland: Box::into_raw(wayland),
-            popover: Wrapped::new(actors::popover::State::new(true)),
+            popover: ArcWrapped::new(actors::popover::State::new(true)),
         }
     }