Refine Window::set_cursor_grab API

This commit renames `Window::set_cursor_grab` to
`Window::set_cursor_grab_mode`. The new API now accepts enumeration
to control the way cursor grab is performed. The value could be: `lock`,
`confine`, or `none`.

This commit also implements `Window::set_cursor_position` for Wayland,
since it's tied to locked cursor.

Implements API from #1677.

src/platform_impl/linux/mod.rs

@@ -9,8 +9,6 @@
 #[cfg(all(not(feature = "x11"), not(feature = "wayland")))]
 compile_error!("Please select a feature to build for unix: `x11`, `wayland`");
 
-#[cfg(feature = "wayland")]
-use crate::window::Theme;
 #[cfg(feature = "wayland")]
 use std::error::Error;
 
@@ -28,6 +26,8 @@ use raw_window_handle::RawWindowHandle;
 pub use self::x11::XNotSupported;
 #[cfg(feature = "x11")]
 use self::x11::{ffi::XVisualInfo, util::WindowType as XWindowType, XConnection, XError};
+#[cfg(feature = "wayland")]
+use crate::window::Theme;
 use crate::{
     dpi::{PhysicalPosition, PhysicalSize, Position, Size},
     error::{ExternalError, NotSupportedError, OsError as RootOsError},
@@ -37,7 +37,7 @@ use crate::{
     },
     icon::Icon,
     monitor::{MonitorHandle as RootMonitorHandle, VideoMode as RootVideoMode},
-    window::{CursorIcon, Fullscreen, UserAttentionType, WindowAttributes},
+    window::{CursorGrabMode, CursorIcon, Fullscreen, UserAttentionType, WindowAttributes},
 };
 
 pub(crate) use crate::icon::RgbaIcon as PlatformIcon;
@@ -388,8 +388,8 @@ impl Window {
     }
 
     #[inline]
-    pub fn set_cursor_grab(&self, grab: bool) -> Result<(), ExternalError> {
-        x11_or_wayland!(match self; Window(window) => window.set_cursor_grab(grab))
+    pub fn set_cursor_grab(&self, mode: CursorGrabMode) -> Result<(), ExternalError> {
+        x11_or_wayland!(match self; Window(window) => window.set_cursor_grab(mode))
     }
 
     #[inline]

src/platform_impl/linux/wayland/env.rs

@@ -24,23 +24,23 @@ use sctk::shm::ShmHandler;
 /// Set of extra features that are supported by the compositor.
 #[derive(Debug, Clone, Copy)]
 pub struct WindowingFeatures {
-    cursor_grab: bool,
+    pointer_constraints: bool,
     xdg_activation: bool,
 }
 
 impl WindowingFeatures {
     /// Create `WindowingFeatures` based on the presented interfaces.
     pub fn new(env: &Environment<WinitEnv>) -> Self {
-        let cursor_grab = env.get_global::<ZwpPointerConstraintsV1>().is_some();
+        let pointer_constraints = env.get_global::<ZwpPointerConstraintsV1>().is_some();
         let xdg_activation = env.get_global::<XdgActivationV1>().is_some();
         Self {
-            cursor_grab,
+            pointer_constraints,
             xdg_activation,
         }
     }
 
-    pub fn cursor_grab(&self) -> bool {
-        self.cursor_grab
+    pub fn pointer_constraints(&self) -> bool {
+        self.pointer_constraints
     }
 
     pub fn xdg_activation(&self) -> bool {

src/platform_impl/linux/wayland/seat/pointer/data.rs

@@ -5,8 +5,9 @@ use std::rc::Rc;
 
 use sctk::reexports::client::protocol::wl_surface::WlSurface;
 use sctk::reexports::client::Attached;
-use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_pointer_constraints_v1::{ZwpPointerConstraintsV1};
+use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_pointer_constraints_v1::ZwpPointerConstraintsV1;
 use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_confined_pointer_v1::ZwpConfinedPointerV1;
+use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_locked_pointer_v1::ZwpLockedPointerV1;
 
 use crate::event::{ModifiersState, TouchPhase};
 
@@ -25,6 +26,7 @@ pub(super) struct PointerData {
     pub pointer_constraints: Option<Attached<ZwpPointerConstraintsV1>>,
 
     pub confined_pointer: Rc<RefCell<Option<ZwpConfinedPointerV1>>>,
+    pub locked_pointer: Rc<RefCell<Option<ZwpLockedPointerV1>>>,
 
     /// Latest observed serial in pointer events.
     pub latest_serial: Rc<Cell<u32>>,
@@ -39,6 +41,7 @@ pub(super) struct PointerData {
 impl PointerData {
     pub fn new(
         confined_pointer: Rc<RefCell<Option<ZwpConfinedPointerV1>>>,
+        locked_pointer: Rc<RefCell<Option<ZwpLockedPointerV1>>>,
         pointer_constraints: Option<Attached<ZwpPointerConstraintsV1>>,
         modifiers_state: Rc<RefCell<ModifiersState>>,
     ) -> Self {
@@ -47,6 +50,7 @@ impl PointerData {
             latest_serial: Rc::new(Cell::new(0)),
             latest_enter_serial: Rc::new(Cell::new(0)),
             confined_pointer,
+            locked_pointer,
             modifiers_state,
             pointer_constraints,
             axis_data: AxisData::new(),

src/platform_impl/linux/wayland/seat/pointer/handlers.rs

@@ -60,6 +60,7 @@ pub(super) fn handle_pointer(
             let winit_pointer = WinitPointer {
                 pointer,
                 confined_pointer: Rc::downgrade(&pointer_data.confined_pointer),
+                locked_pointer: Rc::downgrade(&pointer_data.locked_pointer),
                 pointer_constraints: pointer_data.pointer_constraints.clone(),
                 latest_serial: pointer_data.latest_serial.clone(),
                 latest_enter_serial: pointer_data.latest_enter_serial.clone(),
@@ -104,6 +105,7 @@ pub(super) fn handle_pointer(
             let winit_pointer = WinitPointer {
                 pointer,
                 confined_pointer: Rc::downgrade(&pointer_data.confined_pointer),
+                locked_pointer: Rc::downgrade(&pointer_data.locked_pointer),
                 pointer_constraints: pointer_data.pointer_constraints.clone(),
                 latest_serial: pointer_data.latest_serial.clone(),
                 latest_enter_serial: pointer_data.latest_enter_serial.clone(),

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

@@ -11,6 +11,7 @@ use sctk::reexports::protocols::unstable::relative_pointer::v1::client::zwp_rela
 use sctk::reexports::protocols::unstable::relative_pointer::v1::client::zwp_relative_pointer_v1::ZwpRelativePointerV1;
 use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_pointer_constraints_v1::{ZwpPointerConstraintsV1, Lifetime};
 use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_confined_pointer_v1::ZwpConfinedPointerV1;
+use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_locked_pointer_v1::ZwpLockedPointerV1;
 
 use sctk::seat::pointer::{ThemeManager, ThemedPointer};
 use sctk::window::Window;
@@ -35,9 +36,13 @@ pub struct WinitPointer {
     /// Cursor to handle confine requests.
     confined_pointer: Weak<RefCell<Option<ZwpConfinedPointerV1>>>,
 
+    /// Cursor to handle locked requests.
+    locked_pointer: Weak<RefCell<Option<ZwpLockedPointerV1>>>,
+
     /// Latest observed serial in pointer events.
     /// used by Window::start_interactive_move()
     latest_serial: Rc<Cell<u32>>,
+
     /// Latest observed serial in pointer enter events.
     /// used by Window::set_cursor()
     latest_enter_serial: Rc<Cell<u32>>,
@@ -157,6 +162,52 @@ impl WinitPointer {
         }
     }
 
+    pub fn lock(&self, surface: &WlSurface) {
+        let pointer_constraints = match &self.pointer_constraints {
+            Some(pointer_constraints) => pointer_constraints,
+            None => return,
+        };
+
+        let locked_pointer = match self.locked_pointer.upgrade() {
+            Some(locked_pointer) => locked_pointer,
+            // A pointer is gone.
+            None => return,
+        };
+
+        *locked_pointer.borrow_mut() = Some(init_locked_pointer(
+            pointer_constraints,
+            surface,
+            &*self.pointer,
+        ));
+    }
+
+    pub fn unlock(&self) {
+        let locked_pointer = match self.locked_pointer.upgrade() {
+            Some(locked_pointer) => locked_pointer,
+            // A pointer is gone.
+            None => return,
+        };
+
+        let mut locked_pointer = locked_pointer.borrow_mut();
+
+        if let Some(locked_pointer) = locked_pointer.take() {
+            locked_pointer.destroy();
+        }
+    }
+
+    pub fn set_cursor_position(&self, surface_x: u32, surface_y: u32) {
+        let locked_pointer = match self.locked_pointer.upgrade() {
+            Some(locked_pointer) => locked_pointer,
+            // A pointer is gone.
+            None => return,
+        };
+
+        let locked_pointer = locked_pointer.borrow_mut();
+        if let Some(locked_pointer) = locked_pointer.as_ref() {
+            locked_pointer.set_cursor_position_hint(surface_x.into(), surface_y.into());
+        }
+    }
+
     pub fn drag_window(&self, window: &Window<WinitFrame>) {
         // WlPointer::setart_interactive_move() expects the last serial of *any*
         // pointer event (compare to set_cursor()).
@@ -174,6 +225,9 @@ pub(super) struct Pointers {
 
     /// Confined pointer.
     confined_pointer: Rc<RefCell<Option<ZwpConfinedPointerV1>>>,
+
+    /// Locked pointer.
+    locked_pointer: Rc<RefCell<Option<ZwpLockedPointerV1>>>,
 }
 
 impl Pointers {
@@ -185,11 +239,15 @@ impl Pointers {
         modifiers_state: Rc<RefCell<ModifiersState>>,
     ) -> Self {
         let confined_pointer = Rc::new(RefCell::new(None));
+        let locked_pointer = Rc::new(RefCell::new(None));
+
         let pointer_data = Rc::new(RefCell::new(PointerData::new(
             confined_pointer.clone(),
+            locked_pointer.clone(),
             pointer_constraints.clone(),
             modifiers_state,
         )));
+
         let pointer_seat = seat.detach();
         let pointer = theme_manager.theme_pointer_with_impl(
             seat,
@@ -216,6 +274,7 @@ impl Pointers {
             pointer,
             relative_pointer,
             confined_pointer,
+            locked_pointer,
         }
     }
 }
@@ -232,6 +291,11 @@ impl Drop for Pointers {
             confined_pointer.destroy();
         }
 
+        // Drop lock ponter.
+        if let Some(locked_pointer) = self.locked_pointer.borrow_mut().take() {
+            locked_pointer.destroy();
+        }
+
         // Drop the pointer itself in case it's possible.
         if self.pointer.as_ref().version() >= 3 {
             self.pointer.release();
@@ -264,3 +328,16 @@ pub(super) fn init_confined_pointer(
 
     confined_pointer.detach()
 }
+
+pub(super) fn init_locked_pointer(
+    pointer_constraints: &Attached<ZwpPointerConstraintsV1>,
+    surface: &WlSurface,
+    pointer: &WlPointer,
+) -> ZwpLockedPointerV1 {
+    let locked_pointer =
+        pointer_constraints.lock_pointer(surface, pointer, None, Lifetime::Persistent);
+
+    locked_pointer.quick_assign(move |_, _, _| {});
+
+    locked_pointer.detach()
+}

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

@@ -17,7 +17,9 @@ use crate::platform_impl::{
     MonitorHandle as PlatformMonitorHandle, OsError,
     PlatformSpecificWindowBuilderAttributes as PlatformAttributes,
 };
-use crate::window::{CursorIcon, Fullscreen, Theme, UserAttentionType, WindowAttributes};
+use crate::window::{
+    CursorGrabMode, CursorIcon, Fullscreen, Theme, UserAttentionType, WindowAttributes,
+};
 
 use super::env::WindowingFeatures;
 use super::event_loop::WinitState;
@@ -72,6 +74,9 @@ pub struct Window {
 
     /// Whether the window is decorated.
     decorated: AtomicBool,
+
+    /// Grabbing mode.
+    cursor_grab_mode: Mutex<CursorGrabMode>,
 }
 
 impl Window {
@@ -285,6 +290,7 @@ impl Window {
             windowing_features,
             resizeable: AtomicBool::new(attributes.resizable),
             decorated: AtomicBool::new(attributes.decorations),
+            cursor_grab_mode: Mutex::new(CursorGrabMode::None),
         };
 
         Ok(window)
@@ -474,12 +480,17 @@ impl Window {
     }
 
     #[inline]
-    pub fn set_cursor_grab(&self, grab: bool) -> Result<(), ExternalError> {
-        if !self.windowing_features.cursor_grab() {
+    pub fn set_cursor_grab(&self, mode: CursorGrabMode) -> Result<(), ExternalError> {
+        if !self.windowing_features.pointer_constraints() {
+            if mode == CursorGrabMode::None {
+                return Ok(());
+            }
+
             return Err(ExternalError::NotSupported(NotSupportedError::new()));
         }
 
-        self.send_request(WindowRequest::GrabCursor(grab));
+        *self.cursor_grab_mode.lock().unwrap() = mode;
+        self.send_request(WindowRequest::SetCursorGrabMode(mode));
 
         Ok(())
     }
@@ -494,15 +505,19 @@ impl Window {
     }
 
     #[inline]
-    pub fn set_cursor_position(&self, _: Position) -> Result<(), ExternalError> {
-        // XXX This is possible if the locked pointer is being used. We don't have any
-        // API for that right now, but it could be added in
-        // https://github.com/rust-windowing/winit/issues/1677.
-        //
-        // This function is essential for the locked pointer API.
-        //
-        // See pointer-constraints-unstable-v1.xml.
-        Err(ExternalError::NotSupported(NotSupportedError::new()))
+    pub fn set_cursor_position(&self, position: Position) -> Result<(), ExternalError> {
+        // Positon can be set only for locked cursor.
+        if *self.cursor_grab_mode.lock().unwrap() != CursorGrabMode::Locked {
+            return Err(ExternalError::Os(os_error!(OsError::WaylandMisc(
+                "cursor position can be set only for locked cursor."
+            ))));
+        }
+
+        let scale_factor = self.scale_factor() as f64;
+        let position = position.to_logical(scale_factor);
+        self.send_request(WindowRequest::SetLockedCursorPosition(position));
+
+        Ok(())
     }
 
     #[inline]

src/platform_impl/linux/wayland/window/shim.rs

@@ -19,7 +19,7 @@ use crate::platform_impl::wayland::event_loop::{EventSink, WinitState};
 use crate::platform_impl::wayland::seat::pointer::WinitPointer;
 use crate::platform_impl::wayland::seat::text_input::TextInputHandler;
 use crate::platform_impl::wayland::WindowId;
-use crate::window::{CursorIcon, Theme, UserAttentionType};
+use crate::window::{CursorGrabMode, CursorIcon, Theme, UserAttentionType};
 
 use super::WinitFrame;
 
@@ -40,8 +40,11 @@ pub enum WindowRequest {
     /// Change the cursor icon.
     NewCursorIcon(CursorIcon),
 
-    /// Grab cursor.
-    GrabCursor(bool),
+    /// Change cursor grabbing mode.
+    SetCursorGrabMode(CursorGrabMode),
+
+    /// Set cursor position.
+    SetLockedCursorPosition(LogicalPosition<u32>),
 
     /// Drag window.
     DragWindow,
@@ -172,7 +175,7 @@ pub struct WindowHandle {
     cursor_visible: Cell<bool>,
 
     /// Cursor confined to the surface.
-    confined: Cell<bool>,
+    cursor_grab_mode: Cell<CursorGrabMode>,
 
     /// Pointers over the current surface.
     pointers: Vec<WinitPointer>,
@@ -208,7 +211,7 @@ impl WindowHandle {
             pending_window_requests,
             cursor_icon: Cell::new(CursorIcon::Default),
             is_resizable: Cell::new(true),
-            confined: Cell::new(false),
+            cursor_grab_mode: Cell::new(CursorGrabMode::None),
             cursor_visible: Cell::new(true),
             pointers: Vec::new(),
             text_inputs: Vec::new(),
@@ -219,24 +222,37 @@ impl WindowHandle {
         }
     }
 
-    pub fn set_cursor_grab(&self, grab: bool) {
+    pub fn set_cursor_grab(&self, mode: CursorGrabMode) {
         // The new requested state matches the current confine status, return.
-        if self.confined.get() == grab {
+        let old_mode = self.cursor_grab_mode.replace(mode);
+        if old_mode == mode {
             return;
         }
 
-        self.confined.replace(grab);
+        // Clear old pointer data.
+        match old_mode {
+            CursorGrabMode::None => (),
+            CursorGrabMode::Confined => self.pointers.iter().for_each(|p| p.unconfine()),
+            CursorGrabMode::Locked => self.pointers.iter().for_each(|p| p.unlock()),
+        }
 
-        for pointer in self.pointers.iter() {
-            if self.confined.get() {
-                let surface = self.window.surface();
-                pointer.confine(surface);
-            } else {
-                pointer.unconfine();
+        let surface = self.window.surface();
+        match mode {
+            CursorGrabMode::Locked => self.pointers.iter().for_each(|p| p.lock(surface)),
+            CursorGrabMode::Confined => self.pointers.iter().for_each(|p| p.confine(surface)),
+            CursorGrabMode::None => {
+                // Current lock/confine was already removed.
             }
         }
     }
 
+    pub fn set_locked_cursor_position(&self, position: LogicalPosition<u32>) {
+        // XXX the cursor locking is ensured inside `Window`.
+        self.pointers
+            .iter()
+            .for_each(|p| p.set_cursor_position(position.x, position.y));
+    }
+
     pub fn set_user_attention(&self, request_type: Option<UserAttentionType>) {
         let xdg_activation = match self.xdg_activation.as_ref() {
             None => return,
@@ -284,10 +300,13 @@ impl WindowHandle {
         let position = self.pointers.iter().position(|p| *p == pointer);
 
         if position.is_none() {
-            if self.confined.get() {
-                let surface = self.window.surface();
-                pointer.confine(surface);
+            let surface = self.window.surface();
+            match self.cursor_grab_mode.get() {
+                CursorGrabMode::None => (),
+                CursorGrabMode::Locked => pointer.lock(surface),
+                CursorGrabMode::Confined => pointer.confine(surface),
             }
+
             self.pointers.push(pointer);
         }
 
@@ -302,9 +321,11 @@ impl WindowHandle {
         if let Some(position) = position {
             let pointer = self.pointers.remove(position);
 
-            // Drop the confined pointer.
-            if self.confined.get() {
-                pointer.unconfine();
+            // Drop the grabbing mode.
+            match self.cursor_grab_mode.get() {
+                CursorGrabMode::None => (),
+                CursorGrabMode::Locked => pointer.unlock(),
+                CursorGrabMode::Confined => pointer.unconfine(),
             }
         }
     }
@@ -428,8 +449,11 @@ pub fn handle_window_requests(winit_state: &mut WinitState) {
                     let event_sink = &mut winit_state.event_sink;
                     window_handle.set_ime_allowed(allow, event_sink);
                 }
-                WindowRequest::GrabCursor(grab) => {
-                    window_handle.set_cursor_grab(grab);
+                WindowRequest::SetCursorGrabMode(mode) => {
+                    window_handle.set_cursor_grab(mode);
+                }
+                WindowRequest::SetLockedCursorPosition(position) => {
+                    window_handle.set_locked_cursor_position(position);
                 }
                 WindowRequest::DragWindow => {
                     window_handle.drag_window();

src/platform_impl/linux/x11/window.rs

@@ -22,7 +22,7 @@ use crate::{
         MonitorHandle as PlatformMonitorHandle, OsError, PlatformSpecificWindowBuilderAttributes,
         VideoMode as PlatformVideoMode,
     },
-    window::{CursorIcon, Fullscreen, Icon, UserAttentionType, WindowAttributes},
+    window::{CursorGrabMode, CursorIcon, Fullscreen, Icon, UserAttentionType, WindowAttributes},
 };
 
 use super::{
@@ -106,7 +106,7 @@ pub struct UnownedWindow {
     root: ffi::Window,           // never changes
     screen_id: i32,              // never changes
     cursor: Mutex<CursorIcon>,
-    cursor_grabbed: Mutex<bool>,
+    cursor_grabbed_mode: Mutex<CursorGrabMode>,
     cursor_visible: Mutex<bool>,
     ime_sender: Mutex<ImeSender>,
     pub shared_state: Mutex<SharedState>,
@@ -276,7 +276,7 @@ impl UnownedWindow {
             root,
             screen_id,
             cursor: Default::default(),
-            cursor_grabbed: Mutex::new(false),
+            cursor_grabbed_mode: Mutex::new(CursorGrabMode::None),
             cursor_visible: Mutex::new(true),
             ime_sender: Mutex::new(event_loop.ime_sender.clone()),
             shared_state: SharedState::new(guessed_monitor, &window_attrs),
@@ -1272,64 +1272,75 @@ impl UnownedWindow {
     }
 
     #[inline]
-    pub fn set_cursor_grab(&self, grab: bool) -> Result<(), ExternalError> {
-        let mut grabbed_lock = self.cursor_grabbed.lock();
-        if grab == *grabbed_lock {
+    pub fn set_cursor_grab(&self, mode: CursorGrabMode) -> Result<(), ExternalError> {
+        let mut grabbed_lock = self.cursor_grabbed_mode.lock();
+        if mode == *grabbed_lock {
             return Ok(());
         }
+
         unsafe {
             // We ungrab before grabbing to prevent passive grabs from causing `AlreadyGrabbed`.
             // Therefore, this is common to both codepaths.
             (self.xconn.xlib.XUngrabPointer)(self.xconn.display, ffi::CurrentTime);
         }
-        let result = if grab {
-            let result = unsafe {
-                (self.xconn.xlib.XGrabPointer)(
-                    self.xconn.display,
-                    self.xwindow,
-                    ffi::True,
-                    (ffi::ButtonPressMask
-                        | ffi::ButtonReleaseMask
-                        | ffi::EnterWindowMask
-                        | ffi::LeaveWindowMask
-                        | ffi::PointerMotionMask
-                        | ffi::PointerMotionHintMask
-                        | ffi::Button1MotionMask
-                        | ffi::Button2MotionMask
-                        | ffi::Button3MotionMask
-                        | ffi::Button4MotionMask
-                        | ffi::Button5MotionMask
-                        | ffi::ButtonMotionMask
-                        | ffi::KeymapStateMask) as c_uint,
-                    ffi::GrabModeAsync,
-                    ffi::GrabModeAsync,
-                    self.xwindow,
-                    0,
-                    ffi::CurrentTime,
-                )
-            };
 
-            match result {
-                ffi::GrabSuccess => Ok(()),
-                ffi::AlreadyGrabbed => {
-                    Err("Cursor could not be grabbed: already grabbed by another client")
-                }
-                ffi::GrabInvalidTime => Err("Cursor could not be grabbed: invalid time"),
-                ffi::GrabNotViewable => {
-                    Err("Cursor could not be grabbed: grab location not viewable")
-                }
-                ffi::GrabFrozen => Err("Cursor could not be grabbed: frozen by another client"),
-                _ => unreachable!(),
-            }
-            .map_err(|err| ExternalError::Os(os_error!(OsError::XMisc(err))))
-        } else {
-            self.xconn
+        let result = match mode {
+            CursorGrabMode::None => self
+                .xconn
                 .flush_requests()
-                .map_err(|err| ExternalError::Os(os_error!(OsError::XError(err))))
+                .map_err(|err| ExternalError::Os(os_error!(OsError::XError(err)))),
+            CursorGrabMode::Confined => {
+                let result = unsafe {
+                    (self.xconn.xlib.XGrabPointer)(
+                        self.xconn.display,
+                        self.xwindow,
+                        ffi::True,
+                        (ffi::ButtonPressMask
+                            | ffi::ButtonReleaseMask
+                            | ffi::EnterWindowMask
+                            | ffi::LeaveWindowMask
+                            | ffi::PointerMotionMask
+                            | ffi::PointerMotionHintMask
+                            | ffi::Button1MotionMask
+                            | ffi::Button2MotionMask
+                            | ffi::Button3MotionMask
+                            | ffi::Button4MotionMask
+                            | ffi::Button5MotionMask
+                            | ffi::ButtonMotionMask
+                            | ffi::KeymapStateMask) as c_uint,
+                        ffi::GrabModeAsync,
+                        ffi::GrabModeAsync,
+                        self.xwindow,
+                        0,
+                        ffi::CurrentTime,
+                    )
+                };
+
+                match result {
+                    ffi::GrabSuccess => Ok(()),
+                    ffi::AlreadyGrabbed => {
+                        Err("Cursor could not be confined: already confined by another client")
+                    }
+                    ffi::GrabInvalidTime => Err("Cursor could not be confined: invalid time"),
+                    ffi::GrabNotViewable => {
+                        Err("Cursor could not be confined: confine location not viewable")
+                    }
+                    ffi::GrabFrozen => {
+                        Err("Cursor could not be confined: frozen by another client")
+                    }
+                    _ => unreachable!(),
+                }
+                .map_err(|err| ExternalError::Os(os_error!(OsError::XMisc(err))))
+            }
+            CursorGrabMode::Locked => {
+                return Err(ExternalError::NotSupported(NotSupportedError::new()));
+            }
         };
+
         if result.is_ok() {
-            *grabbed_lock = grab;
+            *grabbed_lock = mode;
         }
+
         result
     }
 
@@ -1386,14 +1397,14 @@ impl UnownedWindow {
 
         // we can't use `set_cursor_grab(false)` here because it doesn't run `XUngrabPointer`
         // if the cursor isn't currently grabbed
-        let mut grabbed_lock = self.cursor_grabbed.lock();
+        let mut grabbed_lock = self.cursor_grabbed_mode.lock();
         unsafe {
             (self.xconn.xlib.XUngrabPointer)(self.xconn.display, ffi::CurrentTime);
         }
         self.xconn
             .flush_requests()
             .map_err(|err| ExternalError::Os(os_error!(OsError::XError(err))))?;
-        *grabbed_lock = false;
+        *grabbed_lock = CursorGrabMode::None;
 
         // we keep the lock until we are done
         self.xconn