input: remove `InputBackend::dispatch_new_events`

CHANGELOG.md

@@ -22,6 +22,8 @@
 - All winit backend internal event types now use `WinitInput` as the backend type.
 - `WinitEventLoop::dispatch_new_events` is now used to receive some `WinitEvent`s.
 - Added `TabletToolType::Unknown` as an option for tablet events
+- Remove `InputBackend::dispatch_new_events`, turning `InputBackend` into a definition of backend event types. Future input backends should be a `calloop::EventSource`.
+- Remove `InputBackend::EventError` associated type as it is unneeded since `dispatch_new_events` was removed.
 
 ### Additions
 

src/backend/input/mod.rs

@@ -1,6 +1,6 @@
 //! Common traits for input backends to receive input from.
 
-use std::{error::Error, path::PathBuf};
+use std::path::PathBuf;
 
 mod tablet;
 
@@ -507,9 +507,6 @@ impl<B: InputBackend> TouchFrameEvent<B> for UnusedEvent {}
 /// need to implement this and provide the same base guarantees about the precision of
 /// given events.
 pub trait InputBackend: Sized {
-    /// Type representing errors that may be returned when processing events
-    type EventError: Error;
-
     /// Type representing input devices
     type Device: Device;
     /// Type representing keyboard events
@@ -543,11 +540,6 @@ pub trait InputBackend: Sized {
 
     /// Special events that are custom to this backend
     type SpecialEvent;
-
-    /// Processes new events and calls the provided callback.
-    fn dispatch_new_events<F>(&mut self, callback: F) -> Result<(), Self::EventError>
-    where
-        F: FnMut(InputEvent<Self>);
 }
 
 /// Different events that can be generated by an input backend

src/backend/libinput/mod.rs

@@ -12,7 +12,6 @@ use input::event;
 #[cfg(feature = "backend_session")]
 use std::path::Path;
 use std::{
-    io::Error as IoError,
     os::unix::io::{AsRawFd, RawFd},
     path::PathBuf,
 };
@@ -355,8 +354,6 @@ impl backend::Event<LibinputInputBackend> for event::touch::TouchFrameEvent {
 impl backend::TouchFrameEvent<LibinputInputBackend> for event::touch::TouchFrameEvent {}
 
 impl InputBackend for LibinputInputBackend {
-    type EventError = IoError;
-
     type Device = libinput::Device;
     type KeyboardKeyEvent = event::keyboard::KeyboardKeyEvent;
     type PointerAxisEvent = event::pointer::PointerAxisEvent;
@@ -374,103 +371,6 @@ impl InputBackend for LibinputInputBackend {
     type TabletToolButtonEvent = event::tablet_tool::TabletToolButtonEvent;
 
     type SpecialEvent = backend::UnusedEvent;
-
-    fn dispatch_new_events<F>(&mut self, mut callback: F) -> Result<(), IoError>
-    where
-        F: FnMut(InputEvent<Self>),
-    {
-        self.context.dispatch()?;
-
-        for event in &mut self.context {
-            match event {
-                libinput::Event::Device(device_event) => match device_event {
-                    event::DeviceEvent::Added(device_added_event) => {
-                        let added = event::EventTrait::device(&device_added_event);
-
-                        info!(self.logger, "New device {:?}", added.sysname(),);
-
-                        callback(InputEvent::DeviceAdded { device: added });
-                    }
-                    event::DeviceEvent::Removed(device_removed_event) => {
-                        let removed = event::EventTrait::device(&device_removed_event);
-
-                        info!(self.logger, "Removed device {:?}", removed.sysname(),);
-
-                        callback(InputEvent::DeviceRemoved { device: removed });
-                    }
-                    _ => {
-                        trace!(self.logger, "Unknown libinput device event");
-                    }
-                },
-                libinput::Event::Touch(touch_event) => match touch_event {
-                    event::TouchEvent::Down(down_event) => {
-                        callback(InputEvent::TouchDown { event: down_event });
-                    }
-                    event::TouchEvent::Motion(motion_event) => {
-                        callback(InputEvent::TouchMotion { event: motion_event });
-                    }
-                    event::TouchEvent::Up(up_event) => {
-                        callback(InputEvent::TouchUp { event: up_event });
-                    }
-                    event::TouchEvent::Cancel(cancel_event) => {
-                        callback(InputEvent::TouchCancel { event: cancel_event });
-                    }
-                    event::TouchEvent::Frame(frame_event) => {
-                        callback(InputEvent::TouchFrame { event: frame_event });
-                    }
-                    _ => {
-                        trace!(self.logger, "Unknown libinput touch event");
-                    }
-                },
-                libinput::Event::Keyboard(keyboard_event) => match keyboard_event {
-                    event::KeyboardEvent::Key(key_event) => {
-                        callback(InputEvent::Keyboard { event: key_event });
-                    }
-                    _ => {
-                        trace!(self.logger, "Unknown libinput keyboard event");
-                    }
-                },
-                libinput::Event::Pointer(pointer_event) => match pointer_event {
-                    event::PointerEvent::Motion(motion_event) => {
-                        callback(InputEvent::PointerMotion { event: motion_event });
-                    }
-                    event::PointerEvent::MotionAbsolute(motion_abs_event) => {
-                        callback(InputEvent::PointerMotionAbsolute {
-                            event: motion_abs_event,
-                        });
-                    }
-                    event::PointerEvent::Axis(axis_event) => {
-                        callback(InputEvent::PointerAxis { event: axis_event });
-                    }
-                    event::PointerEvent::Button(button_event) => {
-                        callback(InputEvent::PointerButton { event: button_event });
-                    }
-                    _ => {
-                        trace!(self.logger, "Unknown libinput pointer event");
-                    }
-                },
-                libinput::Event::Tablet(tablet_event) => match tablet_event {
-                    event::TabletToolEvent::Axis(event) => {
-                        callback(InputEvent::TabletToolAxis { event });
-                    }
-                    event::TabletToolEvent::Proximity(event) => {
-                        callback(InputEvent::TabletToolProximity { event });
-                    }
-                    event::TabletToolEvent::Tip(event) => {
-                        callback(InputEvent::TabletToolTip { event });
-                    }
-                    event::TabletToolEvent::Button(event) => {
-                        callback(InputEvent::TabletToolButton { event });
-                    }
-                    _ => {
-                        trace!(self.logger, "Unknown libinput tablet event");
-                    }
-                },
-                _ => {} //FIXME: What to do with the rest.
-            }
-        }
-        Ok(())
-    }
 }
 
 impl From<event::keyboard::KeyState> for backend::KeyState {
@@ -568,8 +468,101 @@ impl EventSource for LibinputInputBackend {
         F: FnMut(Self::Event, &mut ()) -> Self::Ret,
     {
         if token == self.token {
-            self.dispatch_new_events(|evt| callback(evt, &mut ()))?;
+            self.context.dispatch()?;
+
+            for event in &mut self.context {
+                match event {
+                    libinput::Event::Device(device_event) => match device_event {
+                        event::DeviceEvent::Added(device_added_event) => {
+                            let added = event::EventTrait::device(&device_added_event);
+
+                            info!(self.logger, "New device {:?}", added.sysname(),);
+
+                            callback(InputEvent::DeviceAdded { device: added }, &mut ());
                         }
+                        event::DeviceEvent::Removed(device_removed_event) => {
+                            let removed = event::EventTrait::device(&device_removed_event);
+
+                            info!(self.logger, "Removed device {:?}", removed.sysname(),);
+
+                            callback(InputEvent::DeviceRemoved { device: removed }, &mut ());
+                        }
+                        _ => {
+                            trace!(self.logger, "Unknown libinput device event");
+                        }
+                    },
+                    libinput::Event::Touch(touch_event) => match touch_event {
+                        event::TouchEvent::Down(down_event) => {
+                            callback(InputEvent::TouchDown { event: down_event }, &mut ());
+                        }
+                        event::TouchEvent::Motion(motion_event) => {
+                            callback(InputEvent::TouchMotion { event: motion_event }, &mut ());
+                        }
+                        event::TouchEvent::Up(up_event) => {
+                            callback(InputEvent::TouchUp { event: up_event }, &mut ());
+                        }
+                        event::TouchEvent::Cancel(cancel_event) => {
+                            callback(InputEvent::TouchCancel { event: cancel_event }, &mut ());
+                        }
+                        event::TouchEvent::Frame(frame_event) => {
+                            callback(InputEvent::TouchFrame { event: frame_event }, &mut ());
+                        }
+                        _ => {
+                            trace!(self.logger, "Unknown libinput touch event");
+                        }
+                    },
+                    libinput::Event::Keyboard(keyboard_event) => match keyboard_event {
+                        event::KeyboardEvent::Key(key_event) => {
+                            callback(InputEvent::Keyboard { event: key_event }, &mut ());
+                        }
+                        _ => {
+                            trace!(self.logger, "Unknown libinput keyboard event");
+                        }
+                    },
+                    libinput::Event::Pointer(pointer_event) => match pointer_event {
+                        event::PointerEvent::Motion(motion_event) => {
+                            callback(InputEvent::PointerMotion { event: motion_event }, &mut ());
+                        }
+                        event::PointerEvent::MotionAbsolute(motion_abs_event) => {
+                            callback(
+                                InputEvent::PointerMotionAbsolute {
+                                    event: motion_abs_event,
+                                },
+                                &mut (),
+                            );
+                        }
+                        event::PointerEvent::Axis(axis_event) => {
+                            callback(InputEvent::PointerAxis { event: axis_event }, &mut ());
+                        }
+                        event::PointerEvent::Button(button_event) => {
+                            callback(InputEvent::PointerButton { event: button_event }, &mut ());
+                        }
+                        _ => {
+                            trace!(self.logger, "Unknown libinput pointer event");
+                        }
+                    },
+                    libinput::Event::Tablet(tablet_event) => match tablet_event {
+                        event::TabletToolEvent::Axis(event) => {
+                            callback(InputEvent::TabletToolAxis { event }, &mut ());
+                        }
+                        event::TabletToolEvent::Proximity(event) => {
+                            callback(InputEvent::TabletToolProximity { event }, &mut ());
+                        }
+                        event::TabletToolEvent::Tip(event) => {
+                            callback(InputEvent::TabletToolTip { event }, &mut ());
+                        }
+                        event::TabletToolEvent::Button(event) => {
+                            callback(InputEvent::TabletToolButton { event }, &mut ());
+                        }
+                        _ => {
+                            trace!(self.logger, "Unknown libinput tablet event");
+                        }
+                    },
+                    _ => {} //FIXME: What to do with the rest.
+                }
+            }
+        }
+
         Ok(PostAction::Continue)
     }
 

src/backend/winit/input.rs

@@ -6,12 +6,12 @@ use winit::{
 };
 
 use crate::backend::input::{
-    self, Axis, AxisSource, ButtonState, Device, DeviceCapability, Event, InputBackend, InputEvent, KeyState,
+    self, Axis, AxisSource, ButtonState, Device, DeviceCapability, Event, InputBackend, KeyState,
     KeyboardKeyEvent, PointerAxisEvent, PointerButtonEvent, PointerMotionAbsoluteEvent, TouchCancelEvent,
     TouchDownEvent, TouchMotionEvent, TouchSlot, TouchUpEvent, UnusedEvent,
 };
 
-use super::{WindowSize, WinitError};
+use super::WindowSize;
 
 /// Marker used to define the `InputBackend` types for the winit backend.
 #[derive(Debug)]
@@ -363,8 +363,6 @@ impl From<ElementState> for ButtonState {
 }
 
 impl InputBackend for WinitInput {
-    type EventError = WinitError;
-
     type Device = WinitVirtualDevice;
     type KeyboardKeyEvent = WinitKeyboardInputEvent;
     type PointerAxisEvent = WinitMouseWheelEvent;
@@ -382,11 +380,4 @@ impl InputBackend for WinitInput {
     type TabletToolButtonEvent = UnusedEvent;
 
     type SpecialEvent = UnusedEvent;
-
-    fn dispatch_new_events<F>(&mut self, _callback: F) -> Result<(), Self::EventError>
-    where
-        F: FnMut(InputEvent<Self>),
-    {
-        unreachable!()
-    }
 }

src/backend/x11/input.rs

@@ -1,9 +1,8 @@
 //! Input backend implementation for the X11 backend.
 
-use super::X11Error;
 use crate::{
     backend::input::{
-        self, Axis, AxisSource, ButtonState, Device, DeviceCapability, InputBackend, InputEvent, KeyState,
+        self, Axis, AxisSource, ButtonState, Device, DeviceCapability, InputBackend, KeyState,
         KeyboardKeyEvent, PointerAxisEvent, PointerButtonEvent, PointerMotionAbsoluteEvent, UnusedEvent,
     },
     utils::{Logical, Size},
@@ -182,8 +181,6 @@ impl PointerMotionAbsoluteEvent<X11Input> for X11MouseMovedEvent {
 }
 
 impl InputBackend for X11Input {
-    type EventError = X11Error;
-
     type Device = X11VirtualDevice;
     type KeyboardKeyEvent = X11KeyboardInputEvent;
     type PointerAxisEvent = X11MouseWheelEvent;
@@ -204,13 +201,4 @@ impl InputBackend for X11Input {
     type TabletToolButtonEvent = UnusedEvent;
 
     type SpecialEvent = UnusedEvent;
-
-    fn dispatch_new_events<F>(&mut self, _callback: F) -> Result<(), Self::EventError>
-    where
-        F: FnMut(InputEvent<Self>),
-    {
-        // The implementation of the trait here is exclusively for type definitions.
-        // See `X11Event::Input` to handle input events.
-        unreachable!()
-    }
 }