wayland: register drag & drop events

examples/window.rs

@@ -540,12 +540,18 @@ impl ApplicationHandler for Application {
             WindowEvent::DoubleTapGesture { .. } => {
                 info!("Smart zoom");
             },
+            WindowEvent::HoveredFile(path) => {
+                info!("File hover initiated: {path:?}");
+            },
+            WindowEvent::HoveredFileCancelled => {
+                info!("File hover canceled");
+            },
+            WindowEvent::DroppedFile(path) => {
+                info!("File dropped: {path:?}");
+            },
             WindowEvent::TouchpadPressure { .. }
-            | WindowEvent::HoveredFileCancelled
             | WindowEvent::KeyboardInput { .. }
             | WindowEvent::PointerEntered { .. }
-            | WindowEvent::DroppedFile(_)
-            | WindowEvent::HoveredFile(_)
             | WindowEvent::Destroyed
             | WindowEvent::Moved(_) => (),
         }

src/platform_impl/linux/wayland/seat/data_device/mod.rs

@@ -0,0 +1,329 @@
+use std::io::{BufRead, BufReader};
+use std::os::fd::AsFd;
+use std::path::PathBuf;
+use std::sync::{Arc, Mutex};
+
+use calloop::{LoopHandle, PostAction, RegistrationToken};
+use rustix::pipe::{pipe_with, PipeFlags};
+use sctk::data_device_manager::data_source::DataSourceData;
+use sctk::data_device_manager::ReadPipe;
+use sctk::globals::GlobalData;
+use sctk::reexports::client::globals::{BindError, GlobalList};
+use sctk::reexports::client::protocol::wl_data_device::{Event as WlDataDeviceEvent, WlDataDevice};
+use sctk::reexports::client::protocol::wl_data_device_manager::{DndAction, WlDataDeviceManager};
+use sctk::reexports::client::protocol::wl_data_offer::{Event as WlDataOfferEvent, WlDataOffer};
+use sctk::reexports::client::protocol::wl_data_source::WlDataSource;
+use sctk::reexports::client::protocol::wl_seat::WlSeat;
+use sctk::reexports::client::{
+    delegate_dispatch, event_created_child, Connection, Dispatch, Proxy, QueueHandle,
+};
+use tracing::warn;
+
+use crate::event::WindowEvent;
+use crate::platform_impl::wayland;
+use crate::platform_impl::wayland::state::WinitState;
+use crate::window::WindowId;
+
+pub struct DataDeviceManager {
+    manager: WlDataDeviceManager,
+}
+
+impl DataDeviceManager {
+    pub fn new(
+        globals: &GlobalList,
+        queue_handle: &QueueHandle<WinitState>,
+    ) -> Result<Self, BindError> {
+        let manager = globals.bind(queue_handle, 1..=3, GlobalData)?;
+        Ok(Self { manager })
+    }
+
+    pub fn init_seat_data_device(&self, seat: &WlSeat, queue_handle: &QueueHandle<WinitState>) {
+        let data = DataDeviceData { seat: seat.clone() };
+        self.manager.get_data_device(seat, queue_handle, data);
+    }
+}
+
+impl Dispatch<WlDataDeviceManager, GlobalData, WinitState> for DataDeviceState {
+    fn event(
+        _state: &mut WinitState,
+        _proxy: &WlDataDeviceManager,
+        _event: <WlDataDeviceManager as Proxy>::Event,
+        _data: &GlobalData,
+        _conn: &Connection,
+        _qhandle: &QueueHandle<WinitState>,
+    ) {
+    }
+}
+
+struct DataDeviceData {
+    seat: WlSeat,
+}
+
+impl Dispatch<WlDataDevice, DataDeviceData, WinitState> for DataDeviceState {
+    event_created_child!(WinitState, WlDataDevice, [
+        0 => (WlDataOffer, Default::default())
+    ]);
+
+    fn event(
+        state: &mut WinitState,
+        wl_data_device: &WlDataDevice,
+        event: <WlDataDevice as Proxy>::Event,
+        data: &DataDeviceData,
+        _conn: &Connection,
+        _qhandle: &QueueHandle<WinitState>,
+    ) {
+        let seat_state = match state.seats.get_mut(&data.seat.id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received data device event {event:?} without seat");
+                return;
+            },
+        };
+
+        let data_device_state = match seat_state.data_device_state.as_mut() {
+            Some(data_device_state) => data_device_state,
+            None => {
+                warn!("Received data device event {event:?} without data device state");
+                return;
+            },
+        };
+
+        match event {
+            WlDataDeviceEvent::Enter { serial, surface, x: _, y: _, id } => {
+                let Some(wl_data_offer) = id else {
+                    warn!("Received data device enter event without id");
+                    return;
+                };
+
+                let Some(data_offer) = wl_data_offer.data::<DataOfferData>() else {
+                    warn!("Received data device enter event without data offer");
+                    return;
+                };
+
+                let Some(mime_type) = (match data_offer.mime_types.lock() {
+                    Ok(mime_types) => mime_types
+                        .iter()
+                        .find(|&mime| mime == FILE_TRANSFER_MIME_TYPE)
+                        .map(|mime| mime.clone()),
+                    Err(e) => {
+                        warn!("Failed to lock MIME type vector: {e}");
+                        None
+                    },
+                }) else {
+                    warn!("Data deviced entered with no valid MIME type");
+                    return;
+                };
+
+                wl_data_offer.set_actions(DndAction::Copy, DndAction::Copy);
+                wl_data_offer.accept(serial, Some(mime_type.clone()));
+
+                let (read_fd, write_fd) = match pipe_with(PipeFlags::CLOEXEC | PipeFlags::NONBLOCK)
+                {
+                    Ok((read_fd, write_fd)) => (read_fd, write_fd),
+                    Err(e) => {
+                        warn!("Failed to create pipe to read data offer from: {e}");
+                        return;
+                    },
+                };
+
+                wl_data_offer.receive(mime_type, write_fd.as_fd());
+                let read_pipe = ReadPipe::from(read_fd);
+
+                if let Some(token) = data_device_state.read_token.take() {
+                    warn!("Cancelling previous data device enter read");
+                    data_device_state.loop_handle.remove(token);
+                }
+
+                let window_id = wayland::make_wid(&surface);
+                data_device_state.hovered_window = Some(window_id);
+                data_device_state.offer = Some(wl_data_offer);
+                data_device_state.read_buffer.clear();
+
+                let wl_data_device = wl_data_device.clone();
+                data_device_state.read_token = data_device_state
+                    .loop_handle
+                    .insert_source(read_pipe, move |_, f, state| {
+                        state.dispatched_events = true;
+                        let data = wl_data_device.data::<DataDeviceData>().unwrap();
+
+                        let seat_state = match state.seats.get_mut(&data.seat.id()) {
+                            Some(seat_state) => seat_state,
+                            None => return PostAction::Remove,
+                        };
+
+                        let data_device_state = match seat_state.data_device_state.as_mut() {
+                            Some(data_device_state) => data_device_state,
+                            None => return PostAction::Remove,
+                        };
+
+                        let f: &mut std::fs::File = unsafe { f.get_mut() };
+                        let mut reader = BufReader::new(f);
+
+                        let consumed = match reader.fill_buf() {
+                            Ok(buf) => {
+                                if buf.is_empty() {
+                                    if let Some(hovered) = data_device_state.hovered_window {
+                                        data_device_state.with_file_paths(|paths| {
+                                            for path in paths {
+                                                state.events_sink.push_window_event(
+                                                    WindowEvent::HoveredFile(path),
+                                                    hovered,
+                                                );
+                                            }
+                                        });
+                                    } else {
+                                        warn!("No window specified to push HoveredFile to");
+                                    }
+                                    return PostAction::Remove;
+                                } else {
+                                    data_device_state.read_buffer.extend_from_slice(buf);
+                                }
+                                buf.len()
+                            },
+                            Err(e)
+                                if matches!(
+                                    e.kind(),
+                                    std::io::ErrorKind::Interrupted
+                                        | std::io::ErrorKind::WouldBlock
+                                ) =>
+                            {
+                                return PostAction::Continue;
+                            },
+                            Err(_) => {
+                                return PostAction::Remove;
+                            },
+                        };
+                        reader.consume(consumed);
+
+                        PostAction::Continue
+                    })
+                    .ok();
+            },
+            WlDataDeviceEvent::Motion { time: _, x: _, y: _ } => {},
+            WlDataDeviceEvent::Drop => {
+                if let Some(hovered_window) = data_device_state.hovered_window {
+                    data_device_state.with_file_paths(|paths| {
+                        for path in paths {
+                            state
+                                .events_sink
+                                .push_window_event(WindowEvent::DroppedFile(path), hovered_window);
+                        }
+                    });
+                    data_device_state.finish_offer();
+                }
+            },
+            WlDataDeviceEvent::Leave => {
+                if let Some(hovered_window) = data_device_state.hovered_window {
+                    state
+                        .events_sink
+                        .push_window_event(WindowEvent::HoveredFileCancelled, hovered_window);
+                    data_device_state.finish_offer();
+                }
+            },
+            WlDataDeviceEvent::DataOffer { id: _ } => {},
+            WlDataDeviceEvent::Selection { id: _ } => {},
+            _ => unreachable!(),
+        }
+    }
+}
+
+#[derive(Default)]
+struct DataOfferData {
+    pub mime_types: Arc<Mutex<Vec<String>>>,
+}
+
+impl Dispatch<WlDataOffer, DataOfferData, WinitState> for DataDeviceState {
+    fn event(
+        _state: &mut WinitState,
+        _wl_data_offer: &WlDataOffer,
+        event: <WlDataOffer as Proxy>::Event,
+        data: &DataOfferData,
+        _conn: &Connection,
+        _qhandle: &QueueHandle<WinitState>,
+    ) {
+        match event {
+            WlDataOfferEvent::SourceActions { source_actions: _ } => {},
+            WlDataOfferEvent::Action { dnd_action: _ } => {},
+            WlDataOfferEvent::Offer { mime_type } => match data.mime_types.lock() {
+                Ok(ref mut mime_types) => {
+                    mime_types.push(mime_type);
+                },
+                Err(e) => {
+                    warn!("Failed to lock data offer mime types: {e}");
+                },
+            },
+            _ => unreachable!(),
+        }
+    }
+}
+
+impl Dispatch<WlDataSource, DataSourceData, WinitState> for DataDeviceState {
+    fn event(
+        _state: &mut WinitState,
+        _proxy: &WlDataSource,
+        _event: <WlDataSource as Proxy>::Event,
+        _data: &DataSourceData,
+        _conn: &Connection,
+        _qhandle: &QueueHandle<WinitState>,
+    ) {
+    }
+}
+
+#[derive(Debug)]
+pub struct DataDeviceState {
+    pub loop_handle: LoopHandle<'static, WinitState>,
+    pub hovered_window: Option<WindowId>,
+    pub offer: Option<WlDataOffer>,
+    pub read_token: Option<RegistrationToken>,
+    pub read_buffer: Vec<u8>,
+}
+
+impl DataDeviceState {
+    pub fn new(loop_handle: LoopHandle<'static, WinitState>) -> Self {
+        Self {
+            loop_handle,
+            hovered_window: None,
+            offer: None,
+            read_token: None,
+            read_buffer: Vec::new(),
+        }
+    }
+
+    fn with_file_paths(&mut self, mut callback: impl FnMut(Vec<PathBuf>)) {
+        let mut paths = Vec::new();
+        if let Ok(uri_list) = String::from_utf8(self.read_buffer.clone()) {
+            for line in uri_list.lines() {
+                if line.starts_with("#") {
+                    continue;
+                }
+
+                if let Some(file) = line.strip_prefix("file://") {
+                    paths.push(PathBuf::from(file));
+                } else {
+                    warn!("Non-comment line in URI list missing prefix: '{line}'");
+                }
+            }
+        } else {
+            warn!("Failed to parse URI list from hovered file");
+        }
+        callback(paths);
+    }
+
+    fn finish_offer(&mut self) {
+        self.hovered_window = None;
+        if let Some(offer) = self.offer.take() {
+            offer.finish();
+            offer.destroy();
+        }
+        if let Some(token) = self.read_token.take() {
+            self.loop_handle.remove(token);
+        }
+    }
+}
+
+const FILE_TRANSFER_MIME_TYPE: &str = "text/uri-list";
+
+delegate_dispatch!(WinitState: [WlDataDeviceManager: GlobalData] => DataDeviceState);
+delegate_dispatch!(WinitState: [WlDataDevice: DataDeviceData] => DataDeviceState);
+delegate_dispatch!(WinitState: [WlDataOffer: DataOfferData] => DataDeviceState);
+delegate_dispatch!(WinitState: [WlDataSource: DataSourceData] => DataDeviceState);

src/platform_impl/linux/wayland/seat/mod.rs

@@ -17,11 +17,13 @@ use crate::event::WindowEvent;
 use crate::keyboard::ModifiersState;
 use crate::platform_impl::wayland::state::WinitState;
 
+pub mod data_device;
 mod keyboard;
 mod pointer;
 mod text_input;
 mod touch;
 
+use data_device::DataDeviceState;
 use keyboard::{KeyboardData, KeyboardState};
 pub use pointer::relative_pointer::RelativePointerState;
 pub use pointer::{PointerConstraintsState, WinitPointerData, WinitPointerDataExt};
@@ -52,6 +54,8 @@ pub struct WinitSeatState {
     /// The keyboard bound on the seat.
     keyboard_state: Option<KeyboardState>,
 
+    data_device_state: Option<DataDeviceState>,
+
     /// The current modifiers state on the seat.
     modifiers: ModifiersState,
 
@@ -85,6 +89,13 @@ impl SeatHandler for WinitState {
             },
         };
 
+        if seat_state.data_device_state.is_none() {
+            if let Some(data_device_manager) = &self.data_device_manager {
+                data_device_manager.init_seat_data_device(&seat, queue_handle);
+                seat_state.data_device_state = Some(DataDeviceState::new(self.loop_handle.clone()));
+            }
+        }
+
         match capability {
             SeatCapability::Touch if seat_state.touch.is_none() => {
                 seat_state.touch = self.seat_state.get_touch(queue_handle, &seat).ok();