Add third button emulation.

New properties:
"Evdev Third Button Emulation" → switch on/off
"Evdev Third Button Emulation Timeout" → timeout until event is delivered
"Evdev Third Button Emulation Button" → phys button to be emulated
"Evdev Third Button Emulation Threshold" → move threshold before emulation
is cancelled

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Tested-by: Benjamin Tissoires <tissoire@cena.fr>

6 files changed, 492 insertions, 0 deletions

diff --git a/include/evdev-properties.h b/include/evdev-properties.h
index 7df2876..16f2af7 100644
--- a/include/evdev-properties.h
+++ b/include/evdev-properties.h
@@ -66,4 +66,13 @@
 /* BOOL */
 #define EVDEV_PROP_SWAP_AXES "Evdev Axes Swap"
 
+/* BOOL */
+#define EVDEV_PROP_THIRDBUTTON "Evdev Third Button Emulation"
+/* CARD32 */
+#define EVDEV_PROP_THIRDBUTTON_TIMEOUT "Evdev Third Button Emulation Timeout"
+/* CARD8 */
+#define EVDEV_PROP_THIRDBUTTON_BUTTON "Evdev Third Button Emulation Button"
+/* CARD32 */
+#define EVDEV_PROP_THIRDBUTTON_THRESHOLD "Evdev Third Button Emulation Threshold"
+
 #endif
diff --git a/man/evdev.man b/man/evdev.man
index adb3f8d..931e1a1 100644
--- a/man/evdev.man
+++ b/man/evdev.man
@@ -133,6 +133,31 @@ must be pressed before wheel emulation is started. If the
 is released before this timeout, the original button press/release event
 is sent.  Default: 200. Property: "Evdev Wheel Emulation Timeout".
 .TP 7
+.BI "Option \*qEmulateThirdButton\*q \*q" boolean \*q
+Enable third button emulation. Third button emulation emits a right button
+event (by default) by pressing and holding the first button. The first
+button must be held down for the configured timeout and must not move more
+than the configured threshold for the emulation to activate. Otherwise, the
+first button event is posted as normal. Default: off.  Property: "Evdev
+Third Button Emulation".
+.TP 7
+.BI "Option \*qEmulateThirdButtonTimeout\*q \*q" integer \*q
+Specifies the timeout in milliseconds between the initial button press and
+the generation of the emulated button event.
+Default: 1000. Property: "Evdev Third Button Emulation Timeout".
+.TP 7
+.BI "Option \*qEmulateThirdButtonButton\*q \*q" integer \*q
+Specifies the physical button number to be emitted if third button emulation
+is triggered.
+Default: 3.  Property: "Evdev Third Button Button".
+.TP 7
+.BI "Option \*qEmulateThirdButtonMoveThreshold\*q \*q" integer \*q
+Specifies the maximum move fuzz in device coordinates for third button
+emulation. If the device moves by more than this threshold before the third
+button emulation is triggered, the emulation is cancelled and a first button
+event is generated as normal.
+Default: 20. Property: "Evdev Third Button Emulation Threshold".
+.TP 7
 .BI "Option \*qGrabDevice\*q \*q" boolean \*q
 Force a grab on the event device. Doing so will ensure that no other driver
 can initialise the same device and it will also stop the device from sending
diff --git a/src/Makefile.am b/src/Makefile.am
index a5c89ac..d1efe53 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -35,6 +35,7 @@ AM_CPPFLAGS =-I$(top_srcdir)/include
 @DRIVER_NAME@_drv_la_SOURCES = @DRIVER_NAME@.c \
                                @DRIVER_NAME@.h \
                                emuMB.c \
+                               emuThird.c \
                                emuWheel.c \
                                draglock.c
 
diff --git a/src/emuThird.c b/src/emuThird.c
new file mode 100644
index 0000000..bdf133a
--- /dev/null
+++ b/src/emuThird.c
@@ -0,0 +1,415 @@
+/*
+ * Copyright © 2011 Red Hat, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of the authors
+ * not be used in advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.  The authors make no
+ * representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied
+ * warranty.
+ *
+ * THE AUTHORS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+ * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
+ * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+/* Right mouse button emulation code.
+ * Emulates a right button event if the first button is held down for a
+ * timeout. If the device moves more than a certain amount before the
+ * timeout is over, the emulation is cancelled and a normal button event is
+ * generated.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "evdev.h"
+
+#include <X11/Xatom.h>
+#include <xf86.h>
+#include <xf86Xinput.h>
+#include <exevents.h>
+
+#include <evdev-properties.h>
+
+/* Threshold (in device coordinates) for devices to cancel emulation */
+#define DEFAULT_MOVE_THRESHOLD 20
+
+static Atom prop_3bemu;         /* Right button emulation on/off property   */
+static Atom prop_3btimeout;     /* Right button timeout property            */
+static Atom prop_3bbutton;      /* Right button target physical button      */
+static Atom prop_3bthreshold;   /* Right button move cancellation threshold */
+
+/* State machine for 3rd button emulation */
+enum EmulationState {
+    EM3B_OFF,             /* no event      */
+    EM3B_PENDING,         /* timer pending */
+    EM3B_EMULATING        /* in emulation  */
+};
+
+static void
+Evdev3BEmuPostButtonEvent(InputInfoPtr pInfo, int button, int press)
+{
+    EvdevPtr          pEvdev   = pInfo->private;
+    struct emulate3B *emu3B    = &pEvdev->emulate3B;
+    int               absolute = 0;
+
+    /* if we cancel, emit the button down event at our start position,
+     * not at the current position. Only for absolute devices though. For
+     * relative events, this may be a bit iffy since pointer accel may shoot
+     * us back more than we moved and confuse the user.
+     */
+    if (emu3B->flags & EVDEV_ABSOLUTE_EVENTS)
+        absolute = 1;
+
+    xf86PostButtonEventP(pInfo->dev, absolute, button, press, 0,
+                         (absolute ? 2 : 0), emu3B->startpos);
+}
+
+
+/**
+ * Timer function. Post a button down event to the server.
+ *
+ * @param arg The InputInfoPtr for this device.
+ */
+CARD32
+Evdev3BEmuTimer(OsTimerPtr timer, CARD32 time, pointer arg)
+{
+    InputInfoPtr      pInfo    = (InputInfoPtr)arg;
+    EvdevPtr          pEvdev   = pInfo->private;
+    struct emulate3B *emu3B    = &pEvdev->emulate3B;
+    int               sigstate = 0;
+
+    sigstate = xf86BlockSIGIO ();
+    emu3B->state = EM3B_EMULATING;
+    Evdev3BEmuPostButtonEvent(pInfo, emu3B->button, 1);
+    xf86UnblockSIGIO (sigstate);
+    return 0;
+}
+
+
+/**
+ * Cancel all emulation, reset the timer and reset deltas.
+ */
+static void
+Evdev3BCancel(InputInfoPtr pInfo)
+{
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+
+    if (emu3B->state != EM3B_OFF)
+    {
+        TimerCancel(emu3B->timer);
+        emu3B->state = EM3B_OFF;
+        memset(emu3B->delta, 0, sizeof(emu3B->delta));
+    }
+
+    emu3B->flags = 0;
+}
+
+/**
+ * Emulate a third button on button press. Note that emulation only triggers
+ * on button 1.
+ *
+ * Return TRUE if event was swallowed by middle mouse button emulation,
+ * FALSE otherwise.
+ */
+BOOL
+Evdev3BEmuFilterEvent(InputInfoPtr pInfo, int button, BOOL press)
+{
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+    int               ret    = FALSE;
+
+    if (!emu3B->enabled)
+        goto out;
+
+    if (press)
+        emu3B->buttonstate |= button;
+    else
+        emu3B->buttonstate &= ~button;
+
+    /* Any other button pressed? Cancel timer */
+    if (button != 1)
+    {
+        switch (emu3B->state)
+        {
+            case EM3B_PENDING:
+                Evdev3BEmuPostButtonEvent(pInfo, 1, 1);
+                Evdev3BCancel(pInfo);
+                break;
+            case EM3B_EMULATING:
+                /* We're emulating and now the user pressed a different
+                 * button. Just release the emulating one, tell the user to
+                 * not do that and get on with life */
+                Evdev3BEmuPostButtonEvent(pInfo, emu3B->button, 0);
+                Evdev3BCancel(pInfo);
+                break;
+            default:
+                break;
+        }
+        goto out;
+    }
+
+    /* Don't emulate if any other button is down */
+    if ((emu3B->buttonstate & ~0x1) != 0)
+        goto out;
+
+    /* Release event → cancel, send press and release now. */
+    if (!press)
+    {
+        switch(emu3B->state)
+        {
+            case EM3B_PENDING:
+                Evdev3BEmuPostButtonEvent(pInfo, 1, 1);
+                Evdev3BCancel(pInfo);
+                break;
+            case EM3B_EMULATING:
+                Evdev3BEmuPostButtonEvent(pInfo, emu3B->button, 0);
+                Evdev3BCancel(pInfo);
+                ret = TRUE;
+                break;
+            default:
+                break;
+        }
+
+        goto out;
+    }
+
+    if (press && emu3B->state == EM3B_OFF)
+    {
+        emu3B->state = EM3B_PENDING;
+        emu3B->timer = TimerSet(emu3B->timer, 0, emu3B->timeout,
+                                Evdev3BEmuTimer, pInfo);
+        ret = TRUE;
+        goto out;
+    }
+
+out:
+    return ret;
+}
+
+/**
+ * Handle absolute x/y motion. If the motion is above the threshold, cancel
+ * emulation.
+ */
+void
+Evdev3BEmuProcessAbsMotion(InputInfoPtr pInfo, ValuatorMask *vals)
+{
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+    int               cancel = FALSE;
+    int               axis   = 0;
+
+    if (emu3B->state != EM3B_PENDING)
+    {
+        if (valuator_mask_isset(vals, 0))
+            emu3B->startpos[0] = valuator_mask_get(vals, 0);
+        if (valuator_mask_isset(vals, 1))
+            emu3B->startpos[1] = valuator_mask_get(vals, 1);
+
+        return;
+    }
+
+    if ((emu3B->flags & EVDEV_ABSOLUTE_EVENTS) == 0)
+        emu3B->flags |= EVDEV_ABSOLUTE_EVENTS;
+
+    while (axis <= 1 && !cancel)
+    {
+        if (valuator_mask_isset(vals, axis))
+        {
+            int delta = valuator_mask_get(vals, axis) - emu3B->startpos[axis];
+            if (abs(delta) > emu3B->threshold)
+                cancel = TRUE;
+        }
+        axis++;
+    }
+
+    if (cancel)
+    {
+        Evdev3BEmuPostButtonEvent(pInfo, 1, 1);
+        Evdev3BCancel(pInfo);
+    }
+}
+
+/**
+ * Handle relative x/y motion. If the motion is above the threshold, cancel
+ * emulation.
+ */
+void
+Evdev3BEmuProcessRelMotion(InputInfoPtr pInfo, int dx, int dy)
+{
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+
+    if (emu3B->state != EM3B_PENDING)
+        return;
+
+    emu3B->delta[0] += dx;
+    emu3B->delta[1] += dy;
+    emu3B->flags |= EVDEV_RELATIVE_EVENTS;
+
+    if (abs(emu3B->delta[0]) > emu3B->threshold ||
+        abs(emu3B->delta[1]) > emu3B->threshold)
+    {
+        Evdev3BEmuPostButtonEvent(pInfo, 1, 1);
+        Evdev3BCancel(pInfo);
+    }
+}
+
+void
+Evdev3BEmuPreInit(InputInfoPtr pInfo)
+{
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+
+    emu3B->enabled = xf86SetBoolOption(pInfo->options,
+                                       "EmulateThirdButton",
+                                       FALSE);
+    emu3B->timeout = xf86SetIntOption(pInfo->options,
+                                      "EmulateThirdButtonTimeout",
+                                      1000);
+    emu3B->button = xf86SetBoolOption(pInfo->options,
+                                      "EmulateThirdButtonButton",
+                                      3);
+    /* FIXME: this should be auto-configured based on axis ranges */
+    emu3B->threshold = xf86SetBoolOption(pInfo->options,
+                                         "EmulateThirdButtonMoveThreshold",
+                                         DEFAULT_MOVE_THRESHOLD);
+    /* allocate now so we don't allocate in the signal handler */
+    emu3B->timer = TimerSet(NULL, 0, 0, NULL, NULL);
+}
+
+void
+Evdev3BEmuOn(InputInfoPtr pInfo)
+{
+    /* This function just exists for symmetry in evdev.c */
+}
+
+void
+Evdev3BEmuFinalize(InputInfoPtr pInfo)
+{
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+
+    TimerFree(emu3B->timer);
+    emu3B->timer = NULL;
+}
+
+static int
+Evdev3BEmuSetProperty(DeviceIntPtr dev, Atom atom, XIPropertyValuePtr val,
+                      BOOL checkonly)
+{
+    InputInfoPtr      pInfo  = dev->public.devicePrivate;
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+
+    if (atom == prop_3bemu)
+    {
+        if (val->format != 8 || val->size != 1 || val->type != XA_INTEGER)
+            return BadMatch;
+
+        if (!checkonly)
+            emu3B->enabled = *((BOOL*)val->data);
+
+    } else if (atom == prop_3btimeout)
+    {
+        if (val->format != 32 || val->size != 1 || val->type != XA_INTEGER)
+            return BadMatch;
+
+        if (!checkonly)
+            emu3B->timeout = *((CARD32*)val->data);
+
+    } else if (atom == prop_3bbutton)
+    {
+        if (val->format != 8 || val->size != 1 || val->type != XA_INTEGER)
+            return BadMatch;
+
+        if (!checkonly)
+            emu3B->button = *((CARD8*)val->data);
+    } else if (atom == prop_3bthreshold)
+    {
+        if (val->format != 32 || val->size != 1 || val->type != XA_INTEGER)
+            return BadMatch;
+
+        if (!checkonly)
+            emu3B->threshold = *((CARD32*)val->data);
+    }
+
+
+    return Success;
+}
+
+/**
+ * Initialise properties for third button emulation
+ */
+void
+Evdev3BEmuInitProperty(DeviceIntPtr dev)
+{
+    InputInfoPtr      pInfo  = dev->public.devicePrivate;
+    EvdevPtr          pEvdev = pInfo->private;
+    struct emulate3B *emu3B  = &pEvdev->emulate3B;
+    int               rc;
+
+    if (!dev->button) /* don't init prop for keyboards */
+        return;
+
+    /* third button emulation on/off */
+    prop_3bemu = MakeAtom(EVDEV_PROP_THIRDBUTTON, strlen(EVDEV_PROP_THIRDBUTTON), TRUE);
+    rc = XIChangeDeviceProperty(dev, prop_3bemu, XA_INTEGER, 8,
+                                PropModeReplace, 1,
+                                &emu3B->enabled,
+                                FALSE);
+    if (rc != Success)
+        return;
+
+    XISetDevicePropertyDeletable(dev, prop_3bemu, FALSE);
+
+    /* third button emulation timeout */
+    prop_3btimeout = MakeAtom(EVDEV_PROP_THIRDBUTTON_TIMEOUT,
+                              strlen(EVDEV_PROP_THIRDBUTTON_TIMEOUT),
+                              TRUE);
+    rc = XIChangeDeviceProperty(dev, prop_3btimeout, XA_INTEGER, 32, PropModeReplace, 1,
+                                &emu3B->timeout, FALSE);
+
+    if (rc != Success)
+        return;
+
+    XISetDevicePropertyDeletable(dev, prop_3btimeout, FALSE);
+
+    /* third button emulation button to be triggered  */
+    prop_3bbutton = MakeAtom(EVDEV_PROP_THIRDBUTTON_BUTTON,
+                             strlen(EVDEV_PROP_THIRDBUTTON_BUTTON),
+                             TRUE);
+    rc = XIChangeDeviceProperty(dev, prop_3bbutton, XA_INTEGER, 8, PropModeReplace, 1,
+                                &emu3B->button, FALSE);
+
+    if (rc != Success)
+        return;
+
+    XISetDevicePropertyDeletable(dev, prop_3bbutton, FALSE);
+
+    /* third button emulation movement threshold */
+    prop_3bthreshold = MakeAtom(EVDEV_PROP_THIRDBUTTON_THRESHOLD,
+                                strlen(EVDEV_PROP_THIRDBUTTON_THRESHOLD),
+                                TRUE);
+    rc = XIChangeDeviceProperty(dev, prop_3bthreshold, XA_INTEGER, 32, PropModeReplace, 1,
+                                &emu3B->threshold, FALSE);
+
+    if (rc != Success)
+        return;
+
+    XISetDevicePropertyDeletable(dev, prop_3bthreshold, FALSE);
+
+    XIRegisterPropertyHandler(dev, Evdev3BEmuSetProperty, NULL, NULL);
+}
diff --git a/src/evdev.c b/src/evdev.c
index 74dd04d..bb30655 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -396,6 +396,11 @@ EvdevProcessValuators(InputInfoPtr pInfo)
         if (pEvdev->invert_y)
             pEvdev->delta[REL_Y] *= -1;
 
+
+        Evdev3BEmuProcessRelMotion(pInfo,
+                                   pEvdev->delta[REL_X],
+                                   pEvdev->delta[REL_Y]);
+
         for (i = 0; i < REL_CNT; i++)
         {
             int map = pEvdev->axis_map[i];
@@ -453,6 +458,7 @@ EvdevProcessValuators(InputInfoPtr pInfo)
 
             valuator_mask_set(pEvdev->vals, i, val);
         }
+        Evdev3BEmuProcessAbsMotion(pInfo, pEvdev->vals);
     }
 }
 
@@ -753,6 +759,11 @@ static void EvdevPostQueuedEvents(InputInfoPtr pInfo, int num_v, int first_v,
                                   pEvdev->queue[i].val);
             break;
         case EV_QUEUE_BTN:
+            if (Evdev3BEmuFilterEvent(pInfo,
+                                      pEvdev->queue[i].key,
+                                      pEvdev->queue[i].val))
+                break;
+
             if (pEvdev->abs_queued && pEvdev->in_proximity) {
                 xf86PostButtonEventP(pInfo->dev, 1, pEvdev->queue[i].key,
                                      pEvdev->queue[i].val, first_v, num_v,
@@ -844,6 +855,7 @@ EvdevReadInput(InputInfoPtr pInfo)
             if (errno == ENODEV) /* May happen after resume */
             {
                 EvdevMBEmuFinalize(pInfo);
+                Evdev3BEmuFinalize(pInfo);
                 xf86RemoveEnabledDevice(pInfo);
                 close(pInfo->fd);
                 pInfo->fd = -1;
@@ -1334,6 +1346,7 @@ EvdevInit(DeviceIntPtr device)
     EvdevInitProperty(device);
     XIRegisterPropertyHandler(device, EvdevSetProperty, NULL, NULL);
     EvdevMBEmuInitProperty(device);
+    Evdev3BEmuInitProperty(device);
     EvdevWheelEmuInitProperty(device);
     EvdevDragLockInitProperty(device);
 
@@ -1362,6 +1375,7 @@ EvdevOn(DeviceIntPtr device)
     xf86FlushInput(pInfo->fd);
     xf86AddEnabledDevice(pInfo);
     EvdevMBEmuOn(pInfo);
+    Evdev3BEmuOn(pInfo);
     pEvdev->flags |= EVDEV_INITIALIZED;
     device->public.on = TRUE;
 
@@ -1388,7 +1402,10 @@ EvdevProc(DeviceIntPtr device, int what)
 
     case DEVICE_OFF:
         if (pEvdev->flags & EVDEV_INITIALIZED)
+        {
             EvdevMBEmuFinalize(pInfo);
+            Evdev3BEmuFinalize(pInfo);
+        }
         if (pInfo->fd != -1)
         {
             EvdevGrabDevice(pInfo, 0, 1);
@@ -1862,6 +1879,7 @@ EvdevPreInit(InputDriverPtr drv, InputInfoPtr pInfo, int flags)
     if (pEvdev->flags & EVDEV_BUTTON_EVENTS)
     {
         EvdevMBEmuPreInit(pInfo);
+        Evdev3BEmuPreInit(pInfo);
         EvdevWheelEmuPreInit(pInfo);
         EvdevDragLockPreInit(pInfo);
     }
diff --git a/src/evdev.h b/src/evdev.h
index e68f7f2..5df7d3e 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -136,6 +136,19 @@ typedef struct {
         Time                expires;     /* time of expiry */
         Time                timeout;
     } emulateMB;
+    /* Third mouse button emulation */
+    struct emulate3B {
+        BOOL                enabled;
+        BOOL                state;       /* current state */
+        Time                timeout;     /* timeout until third button press */
+        int                 buttonstate; /* phys. button state */
+        int                 button;      /* phys button to emit */
+        int                 threshold;   /* move threshold in dev coords */
+        OsTimerPtr          timer;
+        int                 delta[2];    /* delta x/y, accumulating */
+        int                 startpos[2]; /* starting pos for abs devices */
+        int                 flags;       /* remember if we had rel or abs movement */
+    } emulate3B;
     struct {
 	int                 meta;           /* meta key to lock any button */
 	BOOL                meta_state;     /* meta_button state */
@@ -204,6 +217,16 @@ void EvdevMBEmuPreInit(InputInfoPtr);
 void EvdevMBEmuOn(InputInfoPtr);
 void EvdevMBEmuFinalize(InputInfoPtr);
 
+/* Third button emulation */
+CARD32 Evdev3BEmuTimer(OsTimerPtr timer, CARD32 time, pointer arg);
+BOOL Evdev3BEmuFilterEvent(InputInfoPtr, int, BOOL);
+void Evdev3BEmuPreInit(InputInfoPtr pInfo);
+void Evdev3BEmuPreInit(InputInfoPtr);
+void Evdev3BEmuOn(InputInfoPtr);
+void Evdev3BEmuFinalize(InputInfoPtr);
+void Evdev3BEmuProcessRelMotion(InputInfoPtr pInfo, int dx, int dy);
+void Evdev3BEmuProcessAbsMotion(InputInfoPtr pInfo, ValuatorMask *vals);
+
 /* Mouse Wheel emulation */
 void EvdevWheelEmuPreInit(InputInfoPtr pInfo);
 BOOL EvdevWheelEmuFilterButton(InputInfoPtr pInfo, unsigned int button, int value);
@@ -214,6 +237,7 @@ void EvdevDragLockPreInit(InputInfoPtr pInfo);
 BOOL EvdevDragLockFilterEvent(InputInfoPtr pInfo, unsigned int button, int value);
 
 void EvdevMBEmuInitProperty(DeviceIntPtr);
+void Evdev3BEmuInitProperty(DeviceIntPtr);
 void EvdevWheelEmuInitProperty(DeviceIntPtr);
 void EvdevDragLockInitProperty(DeviceIntPtr);
 #endif