Merge pull request #510 from robertknight/x11_xinput2

Use XInput2 for event handling

5 files changed, 406 insertions, 91 deletions

diff --git a/src/api/x11/ffi.rs b/src/api/x11/ffi.rs
index 8c9a35d..3d4f0ed 100644
--- a/src/api/x11/ffi.rs
+++ b/src/api/x11/ffi.rs
@@ -2,6 +2,8 @@ pub use x11_dl::keysym::*;
 pub use x11_dl::xcursor::*;
 pub use x11_dl::xf86vmode::*;
 pub use x11_dl::xlib::*;
+pub use x11_dl::xinput::*;
+pub use x11_dl::xinput2::*;
 
 pub use self::glx::types::GLXContext;
 
diff --git a/src/api/x11/input.rs b/src/api/x11/input.rs
new file mode 100644
index 0000000..25add95
--- /dev/null
+++ b/src/api/x11/input.rs
@@ -0,0 +1,328 @@
+use std::sync::Arc;
+
+use libc;
+use std::{mem, ptr};
+use std::ffi::CString;
+use std::slice::from_raw_parts;
+
+use events::Event;
+
+use super::{events, ffi};
+use super::XConnection;
+
+#[derive(Debug)]
+enum AxisType {
+    HorizontalScroll,
+    VerticalScroll
+}
+
+#[derive(Debug)]
+struct Axis {
+    id: i32,
+    device_id: i32,
+    axis_number: i32,
+    axis_type: AxisType
+}
+
+#[derive(Debug)]
+struct AxisValue {
+    device_id: i32,
+    axis_number: i32,
+    value: f64
+}
+
+struct InputState {
+    /// Last-seen cursor position within a window in (x, y)
+    /// coordinates
+    cursor_pos: (f64, f64),
+    /// Last-seen positions of axes, used to report delta
+    /// movements when a new absolute axis value is received
+    axis_values: Vec<AxisValue>
+}
+
+pub struct XInputEventHandler {
+    display: Arc<XConnection>,
+    window: ffi::Window,
+    ic: ffi::XIC,
+    axis_list: Vec<Axis>,
+    current_state: InputState
+}
+
+impl XInputEventHandler {
+    pub fn new(display: &Arc<XConnection>, window: ffi::Window, ic: ffi::XIC) -> XInputEventHandler {
+        // query XInput support
+        let mut opcode: libc::c_int = 0;
+        let mut event: libc::c_int = 0;
+        let mut error: libc::c_int = 0;
+        let xinput_str = CString::new("XInputExtension").unwrap();
+
+        unsafe {
+            if (display.xlib.XQueryExtension)(display.display, xinput_str.as_ptr(), &mut opcode, &mut event, &mut error) == ffi::False {
+                panic!("XInput not available")
+            }
+        }
+
+        let mut xinput_major_ver = ffi::XI_2_Major;
+        let mut xinput_minor_ver = ffi::XI_2_Minor;
+
+        unsafe {
+            if (display.xinput2.XIQueryVersion)(display.display, &mut xinput_major_ver, &mut xinput_minor_ver) != ffi::Success as libc::c_int {
+                panic!("Unable to determine XInput version");
+            }
+        }
+
+        // specify the XInput events we want to receive.
+        // Button clicks and mouse events are handled via XInput
+        // events. Key presses are still handled via plain core
+        // X11 events.
+        let mut mask: [libc::c_uchar; 2] = [0, 0];
+        let mut input_event_mask = ffi::XIEventMask {
+            deviceid: ffi::XIAllDevices,
+            mask_len: mask.len() as i32,
+            mask: mask.as_mut_ptr()
+        };
+        let events = &[
+            ffi::XI_ButtonPress,
+            ffi::XI_ButtonRelease,
+            ffi::XI_Motion,
+            ffi::XI_Enter,
+            ffi::XI_Leave,
+            ffi::XI_FocusIn,
+            ffi::XI_FocusOut
+        ];
+        for event in events {
+            ffi::XISetMask(&mut mask, *event);
+        }
+
+        unsafe {
+            match (display.xinput2.XISelectEvents)(display.display, window, &mut input_event_mask, 1) {
+                status if status as u8 == ffi::Success => (),
+                err => panic!("Failed to select events {:?}", err)
+            }
+        }
+
+        XInputEventHandler {
+            display: display.clone(),
+            window: window,
+            ic: ic,
+            axis_list: read_input_axis_info(display),
+            current_state: InputState {
+                cursor_pos: (0.0, 0.0),
+                axis_values: Vec::new()
+            }
+        }
+    }
+
+    pub fn translate_key_event(&self, event: &mut ffi::XKeyEvent) -> Vec<Event> {
+        use events::Event::{KeyboardInput, ReceivedCharacter};
+        use events::ElementState::{Pressed, Released};
+
+        let mut translated_events = Vec::new();
+
+        let state;
+        if event.type_ == ffi::KeyPress {
+            let raw_ev: *mut ffi::XKeyEvent = event;
+            unsafe { (self.display.xlib.XFilterEvent)(mem::transmute(raw_ev), self.window) };
+            state = Pressed;
+        } else {
+            state = Released;
+        }
+
+        let mut kp_keysym = 0;
+
+        let written = unsafe {
+            use std::str;
+
+            let mut buffer: [u8; 16] = [mem::uninitialized(); 16];
+            let raw_ev: *mut ffi::XKeyEvent = event;
+            let count = (self.display.xlib.Xutf8LookupString)(self.ic, mem::transmute(raw_ev),
+            mem::transmute(buffer.as_mut_ptr()),
+            buffer.len() as libc::c_int, &mut kp_keysym, ptr::null_mut());
+
+            str::from_utf8(&buffer[..count as usize]).unwrap_or("").to_string()
+        };
+
+        for chr in written.chars() {
+            translated_events.push(ReceivedCharacter(chr));
+        }
+
+        let mut keysym = unsafe {
+            (self.display.xlib.XKeycodeToKeysym)(self.display.display, event.keycode as ffi::KeyCode, 0)
+        };
+
+        if (ffi::XK_KP_Space as libc::c_ulong <= keysym) && (keysym <= ffi::XK_KP_9 as libc::c_ulong) {
+            keysym = kp_keysym
+        };
+
+        let vkey = events::keycode_to_element(keysym as libc::c_uint);
+
+        translated_events.push(KeyboardInput(state, event.keycode as u8, vkey));
+        translated_events
+    }
+
+    pub fn translate_event(&mut self, cookie: &ffi::XGenericEventCookie) -> Option<Event> {
+        use events::Event::{Focused, MouseInput, MouseMoved, MouseWheel};
+        use events::ElementState::{Pressed, Released};
+        use events::MouseButton::{Left, Right, Middle};
+        use events::MouseScrollDelta::{PixelDelta, LineDelta};
+
+        match cookie.evtype {
+            ffi::XI_ButtonPress | ffi::XI_ButtonRelease => {
+                let event_data: &ffi::XIDeviceEvent = unsafe{mem::transmute(cookie.data)};
+                let state = if cookie.evtype == ffi::XI_ButtonPress {
+                    Pressed
+                } else {
+                    Released
+                };
+                match event_data.detail as u32 {
+                    ffi::Button1 => Some(MouseInput(state, Left)),
+                    ffi::Button2 => Some(MouseInput(state, Middle)),
+                    ffi::Button3 => Some(MouseInput(state, Right)),
+                    ffi::Button4 | ffi::Button5 => {
+                        if event_data.flags & ffi::XIPointerEmulated == 0 {
+                            // scroll event from a traditional wheel with
+                            // distinct 'clicks'
+                            let delta = if event_data.detail as u32 == ffi::Button4 {
+                                1.0
+                            } else {
+                                -1.0
+                            };
+                            Some(MouseWheel(LineDelta(0.0, delta)))
+                        } else {
+                            // emulated button event from a touch/smooth-scroll
+                            // event. Ignore these events and handle scrolling
+                            // via XI_Motion event handler instead
+                            None
+                        }
+                    }
+                    _ => None
+                }
+            },
+            ffi::XI_Motion => {
+                let event_data: &ffi::XIDeviceEvent = unsafe{mem::transmute(cookie.data)};
+                let axis_state = event_data.valuators;
+                let mask = unsafe{ from_raw_parts(axis_state.mask, axis_state.mask_len as usize) };
+                let mut axis_count = 0;
+
+                let mut scroll_delta = (0.0, 0.0);
+                for axis_id in 0..axis_state.mask_len {
+                    if ffi::XIMaskIsSet(&mask, axis_id) {
+                        let axis_value = unsafe{*axis_state.values.offset(axis_count)};
+                        let delta = calc_scroll_deltas(event_data, axis_id, axis_value, &self.axis_list, 
+                                                       &mut self.current_state.axis_values);
+                        scroll_delta.0 += delta.0;
+                        scroll_delta.1 += delta.1;
+                        axis_count += 1;
+                    }
+                }
+
+                if scroll_delta.0.abs() > 0.0 || scroll_delta.1.abs() > 0.0 {
+                    Some(MouseWheel(PixelDelta(scroll_delta.0 as f32, scroll_delta.1 as f32)))
+                } else {
+                    let new_cursor_pos = (event_data.event_x, event_data.event_y);
+                    if new_cursor_pos != self.current_state.cursor_pos {
+                        self.current_state.cursor_pos = new_cursor_pos;
+                        Some(MouseMoved((new_cursor_pos.0 as i32, new_cursor_pos.1 as i32)))
+                    } else {
+                        None
+                    }
+                }
+            },
+            ffi::XI_Enter => {
+                // axis movements whilst the cursor is outside the window
+                // will alter the absolute value of the axes. We only want to
+                // report changes in the axis value whilst the cursor is above
+                // our window however, so clear the previous axis state whenever
+                // the cursor re-enters the window
+                self.current_state.axis_values.clear();
+                None
+            },
+            ffi::XI_Leave => None,
+            ffi::XI_FocusIn => Some(Focused(true)),
+            ffi::XI_FocusOut => Some(Focused(false)),
+            _ => None
+        }
+    }
+}
+
+fn read_input_axis_info(display: &Arc<XConnection>) -> Vec<Axis> {
+    let mut axis_list = Vec::new();
+    let mut device_count = 0;
+
+    // only get events from the master devices which are 'attached'
+    // to the keyboard or cursor
+    let devices = unsafe{
+        (display.xinput2.XIQueryDevice)(display.display, ffi::XIAllMasterDevices, &mut device_count)
+    };
+    for i in 0..device_count {
+        let device = unsafe { *(devices.offset(i as isize)) };
+        for k in 0..device.num_classes {
+            let class = unsafe { *(device.classes.offset(k as isize)) };
+            match unsafe { (*class)._type } {
+                // Note that scroll axis
+                // are reported both as 'XIScrollClass' and 'XIValuatorClass'
+                // axes. For the moment we only care about scrolling axes.
+                ffi::XIScrollClass => {
+                    let scroll_class: &ffi::XIScrollClassInfo = unsafe{mem::transmute(class)};
+                    axis_list.push(Axis{
+                        id: scroll_class.sourceid,
+                        device_id: device.deviceid,
+                        axis_number: scroll_class.number,
+                        axis_type: match scroll_class.scroll_type {
+                            ffi::XIScrollTypeHorizontal => AxisType::HorizontalScroll,
+                            ffi::XIScrollTypeVertical => AxisType::VerticalScroll,
+                            _ => { unreachable!() }
+                        }
+                    })
+                },
+                _ => {}
+            }
+        }
+    }
+    
+    axis_list
+}
+
+/// Given an input motion event for an axis and the previous
+/// state of the axes, return the horizontal/vertical
+/// scroll deltas
+fn calc_scroll_deltas(event: &ffi::XIDeviceEvent,
+                     axis_id: i32,
+                     axis_value: f64,
+                     axis_list: &[Axis],
+                     prev_axis_values: &mut Vec<AxisValue>) -> (f64, f64) {
+    let prev_value_pos = prev_axis_values.iter().position(|prev_axis| {
+        prev_axis.device_id == event.sourceid &&
+            prev_axis.axis_number == axis_id
+    });
+    let delta = match prev_value_pos {
+        Some(idx) => axis_value - prev_axis_values[idx].value,
+        None => 0.0
+    };
+
+    let new_axis_value = AxisValue{
+        device_id: event.sourceid,
+        axis_number: axis_id,
+        value: axis_value
+    };
+
+    match prev_value_pos {
+        Some(idx) => prev_axis_values[idx] = new_axis_value,
+        None => prev_axis_values.push(new_axis_value)
+    }
+
+    let mut scroll_delta = (0.0, 0.0);
+
+    for axis in axis_list.iter() {
+        if axis.id == event.sourceid &&
+            axis.axis_number == axis_id {
+                match axis.axis_type {
+                    AxisType::HorizontalScroll => scroll_delta.0 = delta,
+                    AxisType::VerticalScroll => scroll_delta.1 = delta
+                }
+            }
+    }
+
+    scroll_delta
+}
+
diff --git a/src/api/x11/mod.rs b/src/api/x11/mod.rs
index e900583..1ba6bc7 100644
--- a/src/api/x11/mod.rs
+++ b/src/api/x11/mod.rs
@@ -7,6 +7,7 @@ pub use self::xdisplay::XConnection;
 pub mod ffi;
 
 mod events;
+mod input;
 mod monitor;
 mod window;
 mod xdisplay;
diff --git a/src/api/x11/window.rs b/src/api/x11/window.rs
index 15e27ce..b13a94a 100644
--- a/src/api/x11/window.rs
+++ b/src/api/x11/window.rs
@@ -2,6 +2,7 @@ use {Event, BuilderAttribs, MouseCursor};
 use CreationError;
 use CreationError::OsError;
 use libc;
+use std::borrow::Borrow;
 use std::{mem, ptr};
 use std::cell::Cell;
 use std::sync::atomic::AtomicBool;
@@ -20,7 +21,8 @@ use api::egl::Context as EglContext;
 
 use platform::MonitorID as PlatformMonitorID;
 
-use super::{events, ffi};
+use super::input::XInputEventHandler;
+use super::{ffi};
 use super::{MonitorID, XConnection};
 
 // XOpenIM doesn't seem to be thread-safe
@@ -106,33 +108,69 @@ impl WindowProxy {
     }
 }
 
+// XEvents of type GenericEvent store their actual data
+// in an XGenericEventCookie data structure. This is a wrapper
+// to extract the cookie from a GenericEvent XEvent and release
+// the cookie data once it has been processed
+struct GenericEventCookie<'a> {
+    display: &'a XConnection,
+    cookie: ffi::XGenericEventCookie
+}
+
+impl<'a> GenericEventCookie<'a> {
+    fn from_event<'b>(display: &'b XConnection, event: ffi::XEvent) -> Option<GenericEventCookie<'b>> {
+        unsafe {
+            let mut cookie: ffi::XGenericEventCookie = From::from(event);
+            if (display.xlib.XGetEventData)(display.display, &mut cookie) == ffi::True {
+                Some(GenericEventCookie{display: display, cookie: cookie})
+            } else {
+                None
+            }
+        }
+    }
+}
+
+impl<'a> Drop for GenericEventCookie<'a> {
+    fn drop(&mut self) {
+        unsafe {
+            let xlib = &self.display.xlib;
+            (xlib.XFreeEventData)(self.display.display, &mut self.cookie);
+        }
+    }
+}
+
 pub struct PollEventsIterator<'a> {
-    window: &'a Window,
+    window: &'a Window
 }
 
 impl<'a> Iterator for PollEventsIterator<'a> {
     type Item = Event;
 
     fn next(&mut self) -> Option<Event> {
-        if let Some(ev) = self.window.pending_events.lock().unwrap().pop_front() {
-            return Some(ev);
-        }
+        let xlib = &self.window.x.display.xlib;
 
         loop {
+            if let Some(ev) = self.window.pending_events.lock().unwrap().pop_front() {
+                return Some(ev);
+            }
+
             let mut xev = unsafe { mem::uninitialized() };
-            let res = unsafe { (self.window.x.display.xlib.XCheckMaskEvent)(self.window.x.display.display, -1, &mut xev) };
+            let res = unsafe { (xlib.XCheckMaskEvent)(self.window.x.display.display, -1, &mut xev) };
 
             if res == 0 {
-                let res = unsafe { (self.window.x.display.xlib.XCheckTypedEvent)(self.window.x.display.display, ffi::ClientMessage, &mut xev) };
+                let res = unsafe { (xlib.XCheckTypedEvent)(self.window.x.display.display, ffi::ClientMessage, &mut xev) };
 
                 if res == 0 {
-                    return None;
+                    let res = unsafe { (xlib.XCheckTypedEvent)(self.window.x.display.display, ffi::GenericEvent, &mut xev) };
+                    if res == 0 {
+                        return None;
+                    }
                 }
             }
 
             match xev.get_type() {
                 ffi::KeymapNotify => {
-                    unsafe { (self.window.x.display.xlib.XRefreshKeyboardMapping)(mem::transmute(&xev)); }
+                    unsafe { (xlib.XRefreshKeyboardMapping)(mem::transmute(&xev)); }
                 },
 
                 ffi::ClientMessage => {
@@ -164,93 +202,34 @@ impl<'a> Iterator for PollEventsIterator<'a> {
                     return Some(Refresh);
                 },
 
-                ffi::MotionNotify => {
-                    use events::Event::MouseMoved;
-                    let event: &ffi::XMotionEvent = unsafe { mem::transmute(&xev) };
-                    return Some(MouseMoved((event.x as i32, event.y as i32)));
-                },
-
-                ffi::KeyPress | ffi::KeyRelease => {
-                    use events::Event::{KeyboardInput, ReceivedCharacter};
-                    use events::ElementState::{Pressed, Released};
-                    let event: &mut ffi::XKeyEvent = unsafe { mem::transmute(&mut xev) };
-
-                    if event.type_ == ffi::KeyPress {
-                        let raw_ev: *mut ffi::XKeyEvent = event;
-                        unsafe { (self.window.x.display.xlib.XFilterEvent)(mem::transmute(raw_ev), self.window.x.window) };
-                    }
-
-                    let state = if xev.get_type() == ffi::KeyPress { Pressed } else { Released };
-
-                    let mut kp_keysym = 0;
-
-                    let written = unsafe {
-                        use std::str;
-
-                        let mut buffer: [u8; 16] = [mem::uninitialized(); 16];
-                        let raw_ev: *mut ffi::XKeyEvent = event;
-                        let count = (self.window.x.display.xlib.Xutf8LookupString)(self.window.x.ic, mem::transmute(raw_ev),
-                            mem::transmute(buffer.as_mut_ptr()),
-                            buffer.len() as libc::c_int, &mut kp_keysym, ptr::null_mut());
-
-                        str::from_utf8(&buffer[..count as usize]).unwrap_or("").to_string()
-                    };
-
-                    {
-                        let mut pending = self.window.pending_events.lock().unwrap();
-                        for chr in written.chars() {
-                            pending.push_back(ReceivedCharacter(chr));
-                        }
+                ffi::KeyPress | ffi::KeyRelease => { 
+                    let mut event: &mut ffi::XKeyEvent = unsafe { mem::transmute(&mut xev) };
+                    let events = self.window.input_handler.lock().unwrap().translate_key_event(&mut event);
+                    for event in events {
+                        self.window.pending_events.lock().unwrap().push_back(event);
                     }
-
-                    let mut keysym = unsafe {
-                        (self.window.x.display.xlib.XKeycodeToKeysym)(self.window.x.display.display, event.keycode as ffi::KeyCode, 0)
-                    };
-
-                    if (ffi::XK_KP_Space as libc::c_ulong <= keysym) && (keysym <= ffi::XK_KP_9 as libc::c_ulong) {
-                        keysym = kp_keysym
-                    };
-
-                    let vkey =  events::keycode_to_element(keysym as libc::c_uint);
-
-                    return Some(KeyboardInput(state, event.keycode as u8, vkey));
                 },
 
-                ffi::ButtonPress | ffi::ButtonRelease => {
-                    use events::Event::{MouseInput, MouseWheel};
-                    use events::ElementState::{Pressed, Released};
-                    use events::MouseButton::{Left, Right, Middle};
-                    use events::MouseScrollDelta::{LineDelta};
-
-                    let event: &ffi::XButtonEvent = unsafe { mem::transmute(&xev) };
-
-                    let state = if xev.get_type() == ffi::ButtonPress { Pressed } else { Released };
-
-                    let button = match event.button {
-                        ffi::Button1 => Some(Left),
-                        ffi::Button2 => Some(Middle),
-                        ffi::Button3 => Some(Right),
-                        ffi::Button4 => {
-                            let delta = LineDelta(0.0, 1.0);
-                            self.window.pending_events.lock().unwrap().push_back(MouseWheel(delta));
-                            None
-                        }
-                        ffi::Button5 => {
-                            let delta = LineDelta(0.0, -1.0);
-                            self.window.pending_events.lock().unwrap().push_back(MouseWheel(delta));
-                            None
+                ffi::GenericEvent => {
+                    if let Some(cookie) = GenericEventCookie::from_event(self.window.x.display.borrow(), xev) {
+                        match cookie.cookie.evtype {
+                            ffi::XI_DeviceChanged...ffi::XI_LASTEVENT => {
+                                match self.window.input_handler.lock() {
+                                    Ok(mut handler) => {
+                                        match handler.translate_event(&cookie.cookie) {
+                                            Some(event) => self.window.pending_events.lock().unwrap().push_back(event),
+                                            None => {}
+                                        }
+                                    },
+                                    Err(_) => {}
+                                }
+                            },
+                            _ => {}
                         }
-                        _ => None
-                    };
-
-                    match button {
-                        Some(button) =>
-                            return Some(MouseInput(state, button)),
-                        None => ()
-                    };
-                },
+                    }
+                }
 
-                _ => ()
+                _ => {}
             };
         }
     }
@@ -296,6 +275,7 @@ pub struct Window {
     /// Events that have been retreived with XLib but not dispatched with iterators yet
     pending_events: Mutex<VecDeque<Event>>,
     cursor_state: Mutex<CursorState>,
+    input_handler: Mutex<XInputEventHandler>
 }
 
 impl Window {
@@ -608,6 +588,7 @@ impl Window {
             pixel_format: pixel_format,
             pending_events: Mutex::new(VecDeque::new()),
             cursor_state: Mutex::new(CursorState::Normal),
+            input_handler: Mutex::new(XInputEventHandler::new(display, window, ic))
         };
 
         // returning
diff --git a/src/api/x11/xdisplay.rs b/src/api/x11/xdisplay.rs
index 9037155..2576b74 100644
--- a/src/api/x11/xdisplay.rs
+++ b/src/api/x11/xdisplay.rs
@@ -12,6 +12,7 @@ pub struct XConnection {
     pub xlib: ffi::Xlib,
     pub xf86vmode: ffi::Xf86vmode,
     pub xcursor: ffi::Xcursor,
+    pub xinput2: ffi::XInput2,
     pub glx: Option<ffi::glx::Glx>,
     pub egl: Option<Egl>,
     pub display: *mut ffi::Display,
@@ -30,6 +31,7 @@ impl XConnection {
         let xlib = try!(ffi::Xlib::open().map_err(|_| XNotSupported));
         let xcursor = try!(ffi::Xcursor::open().map_err(|_| XNotSupported));
         let xf86vmode = try!(ffi::Xf86vmode::open().map_err(|_| XNotSupported));
+        let xinput2 = try!(ffi::XInput2::open().map_err(|_| XNotSupported));
 
         unsafe extern "C" fn x_error_callback(_: *mut ffi::Display, event: *mut ffi::XErrorEvent)
                                               -> libc::c_int
@@ -86,6 +88,7 @@ impl XConnection {
             xlib: xlib,
             xf86vmode: xf86vmode,
             xcursor: xcursor,
+            xinput2: xinput2,
             glx: glx,
             egl: egl,
             display: display,