backend: add DevicesEnumerated event

jay-config/src/_private/client.rs

@@ -42,6 +42,7 @@ pub(crate) struct Client {
     on_new_input_device: RefCell<Option<Rc<dyn Fn(InputDevice)>>>,
     on_connector_connected: RefCell<Option<Rc<dyn Fn(Connector)>>>,
     on_graphics_initialized: Cell<Option<Box<dyn FnOnce()>>>,
+    on_devices_enumerated: Cell<Option<Box<dyn FnOnce()>>>,
     on_new_connector: RefCell<Option<Rc<dyn Fn(Connector)>>>,
     on_new_drm_device: RefCell<Option<Rc<dyn Fn(DrmDevice)>>>,
     on_del_drm_device: RefCell<Option<Rc<dyn Fn(DrmDevice)>>>,
@@ -129,6 +130,7 @@ pub unsafe extern "C" fn init(
         on_new_input_device: Default::default(),
         on_connector_connected: Default::default(),
         on_graphics_initialized: Default::default(),
+        on_devices_enumerated: Default::default(),
         on_new_connector: Default::default(),
         on_new_drm_device: Default::default(),
         on_del_drm_device: Default::default(),
@@ -550,6 +552,10 @@ impl Client {
         self.on_graphics_initialized.set(Some(Box::new(f)));
     }
 
+    pub fn on_devices_enumerated<F: FnOnce() + 'static>(&self, f: F) {
+        self.on_devices_enumerated.set(Some(Box::new(f)));
+    }
+
     pub fn set_seat(&self, device: InputDevice, seat: Seat) {
         self.send(&ClientMessage::SetSeat { device, seat })
     }
@@ -734,6 +740,11 @@ impl Client {
                     handler();
                 }
             }
+            ServerMessage::DevicesEnumerated => {
+                if let Some(handler) = self.on_devices_enumerated.take() {
+                    handler();
+                }
+            }
         }
     }
 

jay-config/src/_private/ipc.rs

@@ -55,6 +55,7 @@ pub enum ServerMessage {
         device: DrmDevice,
     },
     Idle,
+    DevicesEnumerated,
 }
 
 #[derive(Encode, BorrowDecode, Debug)]

jay-config/src/lib.rs

@@ -139,3 +139,11 @@ impl Display for PciId {
 pub fn on_idle<F: Fn() + 'static>(f: F) {
     get!().on_idle(f)
 }
+
+/// Sets the callback to be called when all devices have been enumerated.
+///
+/// This callback is only invoked once during the lifetime of the compositor. This is a
+/// good place to select the DRM device used for rendering.
+pub fn on_devices_enumerated<F: FnOnce() + 'static>(f: F) {
+    get!().on_devices_enumerated(f)
+}