server: verify selection offer is still valid when handling clipboard

Should fix #170, fix #183

src/server/clientside.rs

@@ -3,7 +3,8 @@ use hecs::{Entity, World};
 use smithay_client_toolkit::{
     activation::{ActivationHandler, RequestData, RequestDataExt},
     data_device_manager::{
-        data_device::DataDeviceHandler, data_offer::DataOfferHandler,
+        data_device::{DataDeviceData, DataDeviceHandler},
+        data_offer::{DataOfferHandler, SelectionOffer},
         data_source::DataSourceHandler,
     },
     delegate_activation, delegate_data_device,
@@ -78,7 +79,7 @@ pub(super) struct MyWorld {
     pub new_globals: Vec<Global>,
     events: Vec<(Entity, ObjectEvent)>,
     queued_events: Vec<mpsc::Receiver<(Entity, ObjectEvent)>>,
-    pub selection: Option<wayland_client::protocol::wl_data_device::WlDataDevice>,
+    pub selection_offer: Option<SelectionOffer>,
     pub selection_requests: Vec<(
         String,
         smithay_client_toolkit::data_device_manager::WritePipe,
@@ -95,7 +96,7 @@ impl MyWorld {
             new_globals: Vec::new(),
             events: Vec::new(),
             queued_events: Vec::new(),
-            selection: None,
+            selection_offer: None,
             selection_requests: Vec::new(),
             selection_cancelled: false,
             pending_activations: Vec::new(),
@@ -385,7 +386,8 @@ impl DataDeviceHandler for MyWorld {
         _: &wayland_client::QueueHandle<Self>,
         data_device: &wayland_client::protocol::wl_data_device::WlDataDevice,
     ) {
-        self.selection = Some(data_device.clone());
+        let data: &DataDeviceData = data_device.data().unwrap();
+        self.selection_offer = data.selection_offer();
     }
 
     fn drop_performed(

src/server/mod.rs

@@ -1095,16 +1095,18 @@ impl<C: XConnection> ServerState<C> {
                 }
             }
 
-            if clipboard.source.is_none() || self.world.selection_cancelled {
-                if self.world.selection.take().is_some() {
-                    let device = clipboard.device.as_ref().unwrap();
-                    let offer = device.data().selection_offer().unwrap();
-                    let mime_types: Box<[String]> = offer.with_mime_types(|mimes| mimes.into());
-                    let foreign = ForeignSelection {
-                        mime_types,
-                        inner: offer,
-                    };
-                    clipboard.source = Some(CopyPasteData::Foreign(foreign));
+            if clipboard.source.is_none() {
+                if let Some(offer) = self.world.selection_offer.take() {
+                    if offer.inner().is_alive() {
+                        let mime_types: Box<[String]> = offer.with_mime_types(|mimes| mimes.into());
+                        let foreign = ForeignSelection {
+                            mime_types,
+                            inner: offer,
+                        };
+                        clipboard.source = Some(CopyPasteData::Foreign(foreign));
+                    } else {
+                        clipboard.source = None;
+                    }
                 }
                 self.world.selection_cancelled = false;
             }

src/server/tests.rs

@@ -2427,6 +2427,23 @@ fn output_updated_before_x_connection() {
     assert_eq!(data.dims.x, 0);
     assert_eq!(data.dims.y, 0);
 }
+
+#[test]
+fn quick_empty_data_offer() {
+    let (mut f, comp) = TestFixture::new_with_compositor();
+    TestObject::<WlKeyboard>::from_request(&comp.seat.obj, wl_seat::Request::GetKeyboard {});
+    let win = unsafe { Window::new(1) };
+    let (_surface, _id) = f.create_toplevel(&comp, win);
+    f.testwl.create_data_offer(vec![testwl::PasteData {
+        mime_type: "text".to_string(),
+        data: b"abc".to_vec(),
+    }]);
+    f.testwl.empty_data_offer();
+    f.run();
+
+    let selection = f.satellite.new_selection();
+    assert!(selection.is_none());
+}
 /// See Pointer::handle_event for an explanation.
 #[test]
 fn popup_pointer_motion_workaround() {}

testwl/src/lib.rs

@@ -695,6 +695,20 @@ impl Server {
         self.display.flush_clients().unwrap();
     }
 
+    #[track_caller]
+    pub fn empty_data_offer(&mut self) {
+        let Some(dev) = &self.state.data_device else {
+            panic!("No data device created");
+        };
+
+        if let Some(selection) = self.state.selection.take() {
+            selection.cancelled();
+        }
+
+        dev.selection(None);
+        self.display.flush_clients().unwrap();
+    }
+
     #[track_caller]
     pub fn move_pointer_to(&mut self, surface: SurfaceId, x: f64, y: f64) {
         let pointer = self.state.pointer.as_ref().expect("No pointer created");