Middle emulation - make the emulated button number configurable

Sometimes it may be desirable to remap physical middle button
to something else and use emulation instead. The emulation is
however hardcoded to emulate physical button 2, so the emulated
button gets remapped together with the physical one. This patch
adds the Emulate3Button configuration option to allow for user
selection of the emulated button number and a configuration
like this:

Section "InputClass"
    Identifier "Middle button emulation config"
    MatchProduct ".... some device ..."
    MatchDriver "evdev"
    Option "Emulate3Buttons" "on"
    Option "Emulate3Button" "9"
EndSection

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

include/evdev-properties.h

@@ -33,6 +33,8 @@
 #define EVDEV_PROP_MIDBUTTON "Evdev Middle Button Emulation"
 /* CARD32 */
 #define EVDEV_PROP_MIDBUTTON_TIMEOUT "Evdev Middle Button Timeout"
+/* CARD8 */
+#define EVDEV_PROP_MIDBUTTON_BUTTON "Evdev Middle Button Button"
 
 /* Wheel emulation */
 /* BOOL */

man/evdev.man

@@ -94,6 +94,11 @@ Sets the timeout (in milliseconds) that the driver waits before deciding
 if two buttons where pressed "simultaneously" when 3 button emulation is
 enabled.  Default: 50. Property: "Evdev Middle Button Timeout".
 .TP 7
+.BI "Option \*qEmulate3Button\*q \*q" integer \*q
+Specifies the physical button number to be emitted if middle button emulation
+is triggered.
+Default: 2.  Property: "Evdev Middle Button Button".
+.TP 7
 .BI "Option \*qEmulateWheel\*q \*q" boolean \*q
 Enable/disable "wheel" emulation.  Wheel emulation means emulating button
 press/release events when the mouse is moved while a specific real button
@@ -283,6 +288,9 @@ value.
 .BI "Evdev Middle Button Timeout"
 1 16-bit positive value.
 .TP 7
+.BI "Evdev Middle Button Button"
+1 8-bit value, allowed range 0-32, 0 disables the button.
+.TP 7
 .BI "Evdev Wheel Emulation"
 1 boolean value (8 bit, 0 or 1).
 .TP 7

src/emuMB.c

@@ -45,6 +45,7 @@
 
 static Atom prop_mbemu     = 0; /* Middle button emulation on/off property */
 static Atom prop_mbtimeout = 0; /* Middle button timeout property */
+static Atom prop_mbbuton   = 0; /* Middle button target button property */
 /*
  * Lets create a simple finite-state machine for 3 button emulation:
  *
@@ -185,6 +186,7 @@ EvdevMBEmuTimer(InputInfoPtr pInfo)
 {
     EvdevPtr pEvdev = pInfo->private;
     int id;
+    int mapped_id;
 
 #if HAVE_THREADED_INPUT
     input_lock();
@@ -194,7 +196,10 @@ EvdevMBEmuTimer(InputInfoPtr pInfo)
 
     pEvdev->emulateMB.pending = FALSE;
     if ((id = stateTab[pEvdev->emulateMB.state][4][0]) != 0) {
-        EvdevPostButtonEvent(pInfo, abs(id),
+        mapped_id = abs(id);
+        if (mapped_id == 2)
+            mapped_id = pEvdev->emulateMB.button;
+        EvdevPostButtonEvent(pInfo, mapped_id,
                              (id >= 0) ? BUTTON_PRESS : BUTTON_RELEASE);
         pEvdev->emulateMB.state =
             stateTab[pEvdev->emulateMB.state][4][2];
@@ -226,6 +231,7 @@ EvdevMBEmuFilterEvent(InputInfoPtr pInfo, int button, BOOL press)
 {
     EvdevPtr pEvdev = pInfo->private;
     int id;
+    int mapped_id;
     int *btstate;
     int ret = FALSE;
 
@@ -244,7 +250,10 @@ EvdevMBEmuFilterEvent(InputInfoPtr pInfo, int button, BOOL press)
 
     if ((id = stateTab[pEvdev->emulateMB.state][*btstate][0]) != 0)
     {
-        EvdevQueueButtonEvent(pInfo, abs(id), (id >= 0));
+        mapped_id = abs(id);
+        if (mapped_id == 2)
+            mapped_id = pEvdev->emulateMB.button;
+        EvdevQueueButtonEvent(pInfo, mapped_id, (id >= 0));
         ret = TRUE;
     }
     if ((id = stateTab[pEvdev->emulateMB.state][*btstate][1]) != 0)
@@ -301,12 +310,23 @@ void
 EvdevMBEmuPreInit(InputInfoPtr pInfo)
 {
     EvdevPtr pEvdev = (EvdevPtr)pInfo->private;
+    int bt;
 
     pEvdev->emulateMB.enabled = xf86SetBoolOption(pInfo->options,
                                                   "Emulate3Buttons",
                                                   FALSE);
     pEvdev->emulateMB.timeout = xf86SetIntOption(pInfo->options,
                                                  "Emulate3Timeout", 50);
+    bt = xf86SetIntOption(pInfo->options, "Emulate3Button", 2);
+    if (bt < 0 || bt > EVDEV_MAXBUTTONS) {
+        xf86IDrvMsg(pInfo, X_WARNING, "Invalid Emulate3Button value: %d\n",
+                    bt);
+        xf86IDrvMsg(pInfo, X_WARNING, "Middle button emulation disabled.\n");
+
+        pEvdev->emulateMB.enabled = FALSE;
+    }
+
+    pEvdev->emulateMB.button = bt;
 }
 
 void
@@ -338,6 +358,7 @@ EvdevMBEmuSetProperty(DeviceIntPtr dev, Atom atom, XIPropertyValuePtr val,
 {
     InputInfoPtr pInfo  = dev->public.devicePrivate;
     EvdevPtr     pEvdev = pInfo->private;
+    int bt;
 
     if (atom == prop_mbemu)
     {
@@ -353,6 +374,18 @@ EvdevMBEmuSetProperty(DeviceIntPtr dev, Atom atom, XIPropertyValuePtr val,
 
         if (!checkonly)
             pEvdev->emulateMB.timeout = *((CARD32*)val->data);
+    } else if (atom == prop_mbbuton)
+    {
+        if (val->format != 8 || val->size != 1 || val->type != XA_INTEGER)
+            return BadMatch;
+
+        bt = *((CARD8*)val->data);
+
+        if (bt < 0 || bt > EVDEV_MAXBUTTONS)
+            return BadValue;
+
+        if (!checkonly)
+            pEvdev->emulateMB.button = bt;
     }
 
     return Success;
@@ -390,5 +423,15 @@ EvdevMBEmuInitProperty(DeviceIntPtr dev)
         return;
     XISetDevicePropertyDeletable(dev, prop_mbtimeout, FALSE);
 
+    prop_mbbuton = MakeAtom(EVDEV_PROP_MIDBUTTON_BUTTON,
+                              strlen(EVDEV_PROP_MIDBUTTON_BUTTON),
+                              TRUE);
+    rc = XIChangeDeviceProperty(dev, prop_mbbuton, XA_INTEGER, 8, PropModeReplace, 1,
+                                &pEvdev->emulateMB.button, FALSE);
+
+    if (rc != Success)
+        return;
+    XISetDevicePropertyDeletable(dev, prop_mbbuton, FALSE);
+
     XIRegisterPropertyHandler(dev, EvdevMBEmuSetProperty, NULL, NULL);
 }

src/evdev.h

@@ -196,6 +196,7 @@ typedef struct {
         int                 state;       /* state machine (see bt3emu.c) */
         Time                expires;     /* time of expiry */
         Time                timeout;
+        uint8_t             button;      /* phys button to emit */
     } emulateMB;
     /* Third mouse button emulation */
     struct emulate3B {