backend-server-sys: wakeup when destructors are pending

HackedOS · Apr 19, 2023 · 443a61d · 443a61d
1 parent 04096e2
commit 443a61d
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diff --git a/wayland-backend/CHANGELOG.md b/wayland-backend/CHANGELOG.md
@@ -5,6 +5,8 @@
 #### Bugfixes
 
 - In the rust server backend, don't send `delete_id` messages for server-created objects.
+- In the system server backend, wakeup the event loop if there are pending destructors waiting
+  to be precessed.
 
 ## 0.1.1 -- 16/02/2023
 

diff --git a/wayland-backend/src/sys/server_impl/mod.rs b/wayland-backend/src/sys/server_impl/mod.rs
@@ -298,6 +298,7 @@ struct GlobalUserData<D> {
 pub struct State<D: 'static> {
     display: *mut wl_display,
     pending_destructors: Vec<PendingDestructor<D>>,
+    timer_source: *mut wl_event_source,
     _data: std::marker::PhantomData<fn(&mut D)>,
     known_globals: Vec<InnerGlobalId>,
 }
@@ -343,10 +344,28 @@ impl<D> InnerBackend<D> {
             );
         }
 
+        // Insert a timer we can use to force wakeups of the libwayland inner event loop
+        extern "C" fn timer_noop_cb(_: *mut c_void) -> i32 {
+            0
+        }
+
+        let timer_source = unsafe {
+            let evl = ffi_dispatch!(WAYLAND_SERVER_HANDLE, wl_display_get_event_loop, display);
+
+            ffi_dispatch!(
+                WAYLAND_SERVER_HANDLE,
+                wl_event_loop_add_timer,
+                evl,
+                timer_noop_cb,
+                std::ptr::null_mut()
+            )
+        };
+
         Ok(Self {
             state: Arc::new(Mutex::new(State {
                 display,
                 pending_destructors: Vec::new(),
+                timer_source,
                 _data: std::marker::PhantomData,
                 known_globals: Vec::new(),
             })),
@@ -369,6 +388,18 @@ impl<D> InnerBackend<D> {
                 },
             );
         }
+        if !state.pending_destructors.is_empty() {
+            // Arm the timer to trigger a wakeup of the inner event loop in 1ms, so that the user
+            // is indicated to call dispatch_clients() and have the destructors run
+            unsafe {
+                ffi_dispatch!(
+                    WAYLAND_SERVER_HANDLE,
+                    wl_event_source_timer_update,
+                    state.timer_source,
+                    1
+                )
+            };
+        }
         Ok(())
     }