Re: XInput 2 support

[Po Lu <luangruo@yahoo.com>]

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Po Lu <luangruo@yahoo.com> writes:

> Okay, I asked someone to test and he reported a problem with the menu
> bar.  This updated patch should fix it.

That didn't work either.  This should.


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From 7aa00bdcd92af89e5ff9f3c562e06e0ab40dc58a Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Sat, 16 Oct 2021 13:15:36 +0800
Subject: [PATCH] Add support for event processing via XInput 2

* configure.ac: Add an option to use XInput 2 if available
* src/Makefile.in (XINPUT_LIBS, XINPUT_CFLAGS): New variables
(EMACS_CFLAGS): Add Xinput CFLAGS
(LIBES): Add XInput libs
* src/xfns.c (x_window): Set XInput 2 event mask
* src/xterm.c (x_detect_focus_change): Handle XInput 2 GenericEvents
(handle_one_xevent): Handle XInput 2 events
(x_term_init): Ask the server for XInput 2 support and set xkb_desc if
available
(x_delete_terminal): Free XKB kb desc if it exists
(init_xterm): Don't tell GTK to only use Core Input when built with
XInput 2 support
* src/xterm.h (struct x_display_info): Add fields for XKB and XI2
support
* src/gtkutil.c (xg_event_is_for_menubar): Handle XIDeviceEvents
---
 configure.ac    |  22 ++
 src/Makefile.in |   7 +-
 src/gtkutil.c   |  23 +-
 src/xfns.c      |  56 ++++
 src/xterm.c     | 776 +++++++++++++++++++++++++++++++++++++++++++++++-
 src/xterm.h     |  14 +
 6 files changed, 891 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index 9ab0314428..0af8b65dd7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -485,6 +485,7 @@ AC_DEFUN
 OPTION_DEFAULT_ON([modules],[don't compile with dynamic modules support])
 OPTION_DEFAULT_ON([threads],[don't compile with elisp threading support])
 OPTION_DEFAULT_OFF([native-compilation],[compile with Emacs Lisp native compiler support])
+OPTION_DEFAULT_OFF([xinput2],[use version 2.0 the X Input Extension for input])
 
 AC_ARG_WITH([file-notification],[AS_HELP_STRING([--with-file-notification=LIB],
  [use a file notification library (LIB one of: yes, inotify, kqueue, gfile, w32, no)])],
@@ -4203,6 +4204,26 @@ AC_DEFUN
 AC_SUBST(XFIXES_CFLAGS)
 AC_SUBST(XFIXES_LIBS)
 
+## Use XInput 2.0 if available
+HAVE_XINPUT2=no
+if test "${HAVE_X11}" = "yes" && test "${with_xinput2}" != "no"; then
+   EMACS_CHECK_MODULES([XINPUT], [xi])
+   if test $HAVE_XINPUT = yes; then
+     # Now check for XInput2.h
+     AC_CHECK_HEADER(X11/extensions/XInput2.h,
+       [AC_CHECK_LIB(Xi, XIGrabButton, HAVE_XINPUT2=yes)])
+   fi
+   if test $HAVE_XINPUT2 = yes; then
+     AC_DEFINE(HAVE_XINPUT2, 1, [Define to 1 if the X Input Extension version 2.0 is present.])
+     if test "$USE_GTK_TOOLKIT" = "GTK2"; then
+       AC_MSG_WARN([You are building Emacs with GTK+ 2 and the X Input Extension version 2.
+This might lead to problems if your version of GTK+ is not built with support for XInput 2.])
+     fi
+   fi
+fi
+AC_SUBST(XINPUT_CFLAGS)
+AC_SUBST(XINPUT_LIBS)
+
 ### Use Xdbe (-lXdbe) if available
 HAVE_XDBE=no
 if test "${HAVE_X11}" = "yes"; then
@@ -5959,6 +5980,7 @@ AC_DEFUN
   Does Emacs support legacy unexec dumping?               ${with_unexec}
   Which dumping strategy does Emacs use?                  ${with_dumping}
   Does Emacs have native lisp compiler?                   ${HAVE_NATIVE_COMP}
+  Does Emacs use version 2 of the the X Input Extension?  ${HAVE_XINPUT2}
 "])
 
 if test -n "${EMACSDATA}"; then
diff --git a/src/Makefile.in b/src/Makefile.in
index 6d75e3537a..2b3e1f37e0 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -256,6 +256,9 @@ XINERAMA_CFLAGS =
 XFIXES_LIBS = @XFIXES_LIBS@
 XFIXES_CFLAGS = @XFIXES_CFLAGS@
 
+XINPUT_LIBS = @XINPUT_LIBS@
+XINPUT_CFLAGS = @XINPUT_CFLAGS@
+
 XDBE_LIBS = @XDBE_LIBS@
 XDBE_CFLAGS = @XDBE_CFLAGS@
 
@@ -372,7 +375,7 @@ EMACS_CFLAGS=
   $(GNUSTEP_CFLAGS) $(CFLAGS_SOUND) $(RSVG_CFLAGS) $(IMAGEMAGICK_CFLAGS) \
   $(PNG_CFLAGS) $(LIBXML2_CFLAGS) $(LIBGCCJIT_CFLAGS) $(DBUS_CFLAGS) \
   $(XRANDR_CFLAGS) $(XINERAMA_CFLAGS) $(XFIXES_CFLAGS) $(XDBE_CFLAGS) \
-  $(WEBKIT_CFLAGS) $(LCMS2_CFLAGS) \
+  $(XINPUT_CFLAGS) $(WEBKIT_CFLAGS) $(LCMS2_CFLAGS) \
   $(SETTINGS_CFLAGS) $(FREETYPE_CFLAGS) $(FONTCONFIG_CFLAGS) \
   $(HARFBUZZ_CFLAGS) $(LIBOTF_CFLAGS) $(M17N_FLT_CFLAGS) $(DEPFLAGS) \
   $(LIBSYSTEMD_CFLAGS) $(JSON_CFLAGS) \
@@ -522,7 +525,7 @@ LIBES =
    $(FREETYPE_LIBS) $(FONTCONFIG_LIBS) $(HARFBUZZ_LIBS) $(LIBOTF_LIBS) $(M17N_FLT_LIBS) \
    $(LIBGNUTLS_LIBS) $(LIB_PTHREAD) $(GETADDRINFO_A_LIBS) $(LCMS2_LIBS) \
    $(NOTIFY_LIBS) $(LIB_MATH) $(LIBZ) $(LIBMODULES) $(LIBSYSTEMD_LIBS) \
-   $(JSON_LIBS) $(LIBGMP) $(LIBGCCJIT_LIBS)
+   $(JSON_LIBS) $(LIBGMP) $(LIBGCCJIT_LIBS) $(XINPUT_LIBS)
 
 ## FORCE it so that admin/unidata can decide whether this file is
 ## up-to-date.  Although since charprop depends on bootstrap-emacs,
diff --git a/src/gtkutil.c b/src/gtkutil.c
index e87845caf7..0304f02434 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -47,6 +47,10 @@ Copyright (C) 2003-2021 Free Software Foundation, Inc.
 
 #include <gdk/gdkkeysyms.h>
 
+#ifdef HAVE_XINPUT2
+#include <X11/extensions/XInput2.h>
+#endif
+
 #ifdef HAVE_XFT
 #include <X11/Xft/Xft.h>
 #endif
@@ -3575,6 +3579,18 @@ xg_event_is_for_menubar (struct frame *f, const XEvent *event)
 
   if (! x->menubar_widget) return 0;
 
+#ifdef HAVE_XINPUT2
+  XIDeviceEvent *xev = (XIDeviceEvent *) event->xcookie.data;
+  if (event->type == GenericEvent) /* XI_ButtonPress or XI_ButtonRelease */
+    {
+      if (! (xev->event_x >= 0
+	     && xev->event_x < FRAME_PIXEL_WIDTH (f)
+	     && xev->event_y >= 0
+	     && xev->event_y < FRAME_MENUBAR_HEIGHT (f)))
+	return 0;
+    }
+  else
+#endif
   if (! (event->xbutton.x >= 0
          && event->xbutton.x < FRAME_PIXEL_WIDTH (f)
          && event->xbutton.y >= 0
@@ -3583,7 +3599,12 @@ xg_event_is_for_menubar (struct frame *f, const XEvent *event)
     return 0;
 
   gdpy = gdk_x11_lookup_xdisplay (FRAME_X_DISPLAY (f));
-  gw = gdk_x11_window_lookup_for_display (gdpy, event->xbutton.window);
+#ifdef HAVE_XINPUT2
+  if (event->type == GenericEvent)
+    gw = gdk_x11_window_lookup_for_display (gdpy, xev->event);
+  else
+#endif
+    gw = gdk_x11_window_lookup_for_display (gdpy, event->xbutton.window);
   if (! gw) return 0;
   gevent.any.window = gw;
   gevent.any.type = GDK_NOTHING;
diff --git a/src/xfns.c b/src/xfns.c
index 785ae3baca..4fef8005a0 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -57,6 +57,10 @@ Copyright (C) 1989, 1992-2021 Free Software Foundation, Inc.
 #include <X11/extensions/Xdbe.h>
 #endif
 
+#ifdef HAVE_XINPUT2
+#include <X11/extensions/XInput2.h>
+#endif
+
 #ifdef USE_X_TOOLKIT
 #include <X11/Shell.h>
 
@@ -3074,6 +3078,32 @@ x_window (struct frame *f, long window_prompting)
   class_hints.res_class = SSDATA (Vx_resource_class);
   XSetClassHint (FRAME_X_DISPLAY (f), XtWindow (shell_widget), &class_hints);
 
+#ifdef HAVE_XINPUT2
+  if (FRAME_DISPLAY_INFO (f)->supports_xi2)
+    {
+      XIEventMask mask;
+      ptrdiff_t l = XIMaskLen (XI_LASTEVENT);
+      unsigned char *m;
+      mask.mask = m = alloca (l);
+      memset (m, 0, l);
+      mask.mask_len = l;
+      mask.deviceid = XIAllMasterDevices;
+
+      XISetMask (m, XI_ButtonPress);
+      XISetMask (m, XI_ButtonRelease);
+      XISetMask (m, XI_KeyPress);
+      XISetMask (m, XI_KeyRelease);
+      XISetMask (m, XI_Motion);
+      XISetMask (m, XI_Enter);
+      XISetMask (m, XI_Leave);
+      XISetMask (m, XI_FocusIn);
+      XISetMask (m, XI_FocusOut);
+      XISelectEvents (FRAME_X_DISPLAY (f),
+		      FRAME_X_WINDOW (f),
+		      &mask, 1);
+    }
+#endif
+
 #ifdef HAVE_X_I18N
   FRAME_XIC (f) = NULL;
   if (use_xim)
@@ -3254,6 +3284,32 @@ x_window (struct frame *f)
     }
 #endif /* HAVE_X_I18N */
 
+#ifdef HAVE_XINPUT2
+  if (FRAME_DISPLAY_INFO (f)->supports_xi2)
+    {
+      XIEventMask mask;
+      ptrdiff_t l = XIMaskLen (XI_LASTEVENT);
+      unsigned char *m;
+      mask.mask = m = alloca (l);
+      memset (m, 0, l);
+      mask.mask_len = l;
+      mask.deviceid = XIAllMasterDevices;
+
+      XISetMask (m, XI_ButtonPress);
+      XISetMask (m, XI_ButtonRelease);
+      XISetMask (m, XI_KeyPress);
+      XISetMask (m, XI_KeyRelease);
+      XISetMask (m, XI_Motion);
+      XISetMask (m, XI_Enter);
+      XISetMask (m, XI_Leave);
+      XISetMask (m, XI_FocusIn);
+      XISetMask (m, XI_FocusOut);
+      XISelectEvents (FRAME_X_DISPLAY (f),
+		      FRAME_X_WINDOW (f),
+		      &mask, 1);
+    }
+#endif
+
   validate_x_resource_name ();
 
   class_hints.res_name = SSDATA (Vx_resource_name);
diff --git a/src/xterm.c b/src/xterm.c
index 961c61c245..0435ad341c 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -42,6 +42,10 @@ Copyright (C) 1989, 1993-2021 Free Software Foundation, Inc.
 #include <X11/extensions/Xdbe.h>
 #endif
 
+#ifdef HAVE_XINPUT2
+#include <X11/extensions/XInput2.h>
+#endif
+
 /* Load sys/types.h if not already loaded.
    In some systems loading it twice is suicidal.  */
 #ifndef makedev
@@ -223,9 +227,15 @@ #define XtNinitialState "initialState"
 static void x_check_fullscreen (struct frame *);
 static void x_check_expected_move (struct frame *, int, int);
 static void x_sync_with_move (struct frame *, int, int, bool);
+#ifndef HAVE_XINPUT2
 static int handle_one_xevent (struct x_display_info *,
 			      const XEvent *, int *,
 			      struct input_event *);
+#else
+static int handle_one_xevent (struct x_display_info *,
+			      XEvent *, int *,
+			      struct input_event *);
+#endif
 #if ! (defined USE_X_TOOLKIT || defined USE_MOTIF) && defined USE_GTK
 static int x_dispatch_event (XEvent *, Display *);
 #endif
@@ -4665,7 +4675,16 @@ x_any_window_to_frame (struct x_display_info *dpyinfo, int wdesc)
 x_menubar_window_to_frame (struct x_display_info *dpyinfo,
 			   const XEvent *event)
 {
-  Window wdesc = event->xany.window;
+  Window wdesc;
+#ifdef HAVE_XINPUT2
+  if (event->type == GenericEvent
+      && dpyinfo->supports_xi2
+      && (event->xcookie.evtype == XI_ButtonPress
+	  || event->xcookie.evtype == XI_ButtonRelease))
+    wdesc = ((XIDeviceEvent *) event->xcookie.data)->event;
+#endif
+  else
+    wdesc = event->xany.window;
   Lisp_Object tail, frame;
   struct frame *f;
   struct x_output *x;
@@ -4768,6 +4787,29 @@ x_detect_focus_change (struct x_display_info *dpyinfo, struct frame *frame,
       }
       break;
 
+#ifdef HAVE_XINPUT2
+    case GenericEvent:
+      {
+	XIEvent *xi_event = (XIEvent *) event;
+
+        struct frame *focus_frame = dpyinfo->x_focus_event_frame;
+        int focus_state
+          = focus_frame ? focus_frame->output_data.x->focus_state : 0;
+
+	if (!((xi_event->evtype == XI_Enter
+	       || xi_event->evtype == XI_Leave)
+	      && (focus_state & FOCUS_EXPLICIT)))
+	  x_focus_changed ((xi_event->evtype == XI_Enter
+			    || xi_event->evtype == XI_FocusIn
+			    ? FocusIn : FocusOut),
+			   (xi_event->evtype == XI_Enter
+			    || xi_event->evtype == XI_Leave
+			    ? FOCUS_IMPLICIT : FOCUS_EXPLICIT),
+			   dpyinfo, frame, bufp);
+	break;
+      }
+#endif
+
     case FocusIn:
     case FocusOut:
       /* Ignore transient focus events from hotkeys, window manager
@@ -7872,7 +7914,11 @@ mouse_or_wdesc_frame (struct x_display_info *dpyinfo, int wdesc)
 
 static int
 handle_one_xevent (struct x_display_info *dpyinfo,
+#ifndef HAVE_XINPUT2
 		   const XEvent *event,
+#else
+		   XEvent *event,
+#endif
 		   int *finish, struct input_event *hold_quit)
 {
   union buffered_input_event inev;
@@ -7898,7 +7944,14 @@ handle_one_xevent (struct x_display_info *dpyinfo,
   inev.ie.kind = NO_EVENT;
   inev.ie.arg = Qnil;
 
-  any = x_any_window_to_frame (dpyinfo, event->xany.window);
+#ifdef HAVE_XINPUT2
+  if (event->type != GenericEvent)
+#endif
+    any = x_any_window_to_frame (dpyinfo, event->xany.window);
+#ifdef HAVE_XINPUT2
+  else
+    any = NULL;
+#endif
 
   if (any && any->wait_event_type == event->type)
     any->wait_event_type = 0; /* Indicates we got it.  */
@@ -9343,6 +9396,685 @@ handle_one_xevent (struct x_display_info *dpyinfo,
     case DestroyNotify:
       xft_settings_event (dpyinfo, event);
       break;
+#ifdef HAVE_XINPUT2
+    case GenericEvent:
+      {
+	if (!dpyinfo->supports_xi2)
+	  goto OTHER;
+	if (event->xgeneric.extension != dpyinfo->xi2_opcode)
+	  /* Not an XI2 event. */
+	  goto OTHER;
+	bool must_free_data = false;
+	XIEvent *xi_event = (XIEvent *) event->xcookie.data;
+	/* Sometimes the event is already claimed by GTK, which
+	   will free its data in due course. */
+	if (!xi_event && XGetEventData (dpyinfo->display, &event->xcookie))
+	  {
+	    must_free_data = true;
+	    xi_event = (XIEvent *) event->xcookie.data;
+	  }
+
+	XIDeviceEvent *xev = (XIDeviceEvent *) xi_event;
+	XILeaveEvent *leave = (XILeaveEvent *) xi_event;
+	XIEnterEvent *enter = (XIEnterEvent *) xi_event;
+	XIFocusInEvent *focusin = (XIFocusInEvent *) xi_event;
+	XIFocusOutEvent *focusout = (XIFocusOutEvent *) xi_event;
+
+	/* A fake XMotionEvent for x_note_mouse_movement. */
+	XMotionEvent ev;
+	/* A fake XButtonEvent for x_construct_mouse_click. */
+	XButtonEvent bv;
+
+	if (!xi_event)
+	  {
+	    eassert (!must_free_data);
+	    goto OTHER;
+	  }
+
+	switch (event->xcookie.evtype)
+	  {
+	  case XI_FocusIn:
+	    any = x_any_window_to_frame (dpyinfo, focusin->event);
+#ifndef USE_GTK
+	    /* Some WMs (e.g. Mutter in Gnome Shell), don't unmap
+	       minimized/iconified windows; thus, for those WMs we won't get
+	       a MapNotify when unminimizing/deconifying.  Check here if we
+	       are deiconizing a window (Bug42655).
+
+	       But don't do that on GTK since it may cause a plain invisible
+	       frame get reported as iconified, compare
+	       https://lists.gnu.org/archive/html/emacs-devel/2017-02/msg00133.html.
+	       That is fixed above but bites us here again.  */
+	    f = any;
+	    if (f && FRAME_ICONIFIED_P (f))
+	      {
+		SET_FRAME_VISIBLE (f, 1);
+		SET_FRAME_ICONIFIED (f, false);
+		f->output_data.x->has_been_visible = true;
+		inev.ie.kind = DEICONIFY_EVENT;
+		XSETFRAME (inev.ie.frame_or_window, f);
+	      }
+#endif /* USE_GTK */
+	    x_detect_focus_change (dpyinfo, any, event, &inev.ie);
+	    goto XI_OTHER;
+	  case XI_FocusOut:
+	    any = x_any_window_to_frame (dpyinfo, focusout->event);
+	    x_detect_focus_change (dpyinfo, any, event, &inev.ie);
+	    goto XI_OTHER;
+	  case XI_Enter:
+	    any = x_any_window_to_frame (dpyinfo, enter->event);
+	    ev.x = lrint (enter->event_x);
+	    ev.y = lrint (enter->event_y);
+	    ev.window = leave->event;
+
+	    x_display_set_last_user_time (dpyinfo, xi_event->time);
+	    x_detect_focus_change (dpyinfo, any, event, &inev.ie);
+	    f = any;
+
+	    if (f && x_mouse_click_focus_ignore_position)
+	      ignore_next_mouse_click_timeout = xi_event->time + 200;
+
+	    /* EnterNotify counts as mouse movement,
+	       so update things that depend on mouse position.  */
+	    if (f && !f->output_data.x->hourglass_p)
+	      x_note_mouse_movement (f, &ev);
+#ifdef USE_GTK
+	    /* We may get an EnterNotify on the buttons in the toolbar.  In that
+	       case we moved out of any highlighted area and need to note this.  */
+	    if (!f && dpyinfo->last_mouse_glyph_frame)
+	      x_note_mouse_movement (dpyinfo->last_mouse_glyph_frame, &ev);
+#endif
+	    goto XI_OTHER;
+	  case XI_Leave:
+	    ev.x = lrint (leave->event_x);
+	    ev.y = lrint (leave->event_y);
+	    ev.window = leave->event;
+	    any = x_any_window_to_frame (dpyinfo, leave->event);
+
+	    x_display_set_last_user_time (dpyinfo, xi_event->time);
+	    x_detect_focus_change (dpyinfo, any, event, &inev.ie);
+
+	    f = x_top_window_to_frame (dpyinfo, leave->event);
+	    if (f)
+	      {
+		if (f == hlinfo->mouse_face_mouse_frame)
+		  {
+		    /* If we move outside the frame, then we're
+		       certainly no longer on any text in the frame.  */
+		    clear_mouse_face (hlinfo);
+		    hlinfo->mouse_face_mouse_frame = 0;
+		  }
+
+		/* Generate a nil HELP_EVENT to cancel a help-echo.
+		   Do it only if there's something to cancel.
+		   Otherwise, the startup message is cleared when
+		   the mouse leaves the frame.  */
+		if (any_help_event_p)
+		  do_help = -1;
+	      }
+#ifdef USE_GTK
+	    /* See comment in EnterNotify above */
+	    else if (dpyinfo->last_mouse_glyph_frame)
+	      x_note_mouse_movement (dpyinfo->last_mouse_glyph_frame, &ev);
+#endif
+	    goto XI_OTHER;
+	  case XI_Motion:
+	    ev.x = lrint (xev->event_x);
+	    ev.y = lrint (xev->event_y);
+	    ev.window = xev->event;
+
+	    x_display_set_last_user_time (dpyinfo, xi_event->time);
+	    previous_help_echo_string = help_echo_string;
+	    help_echo_string = Qnil;
+
+	    if (hlinfo->mouse_face_hidden)
+	      {
+		hlinfo->mouse_face_hidden = false;
+		clear_mouse_face (hlinfo);
+	      }
+
+	    f = mouse_or_wdesc_frame (dpyinfo, xev->event);
+
+#ifdef USE_GTK
+	    if (f && xg_event_is_for_scrollbar (f, event))
+	      f = 0;
+#endif
+	    if (f)
+	      {
+		/* Maybe generate a SELECT_WINDOW_EVENT for
+		   `mouse-autoselect-window' but don't let popup menus
+		   interfere with this (Bug#1261).  */
+		if (!NILP (Vmouse_autoselect_window)
+		    && !popup_activated ()
+		    /* Don't switch if we're currently in the minibuffer.
+		       This tries to work around problems where the
+		       minibuffer gets unselected unexpectedly, and where
+		       you then have to move your mouse all the way down to
+		       the minibuffer to select it.  */
+		    && !MINI_WINDOW_P (XWINDOW (selected_window))
+		    /* With `focus-follows-mouse' non-nil create an event
+		       also when the target window is on another frame.  */
+		    && (f == XFRAME (selected_frame)
+			|| !NILP (focus_follows_mouse)))
+		  {
+		    static Lisp_Object last_mouse_window;
+		    Lisp_Object window = window_from_coordinates (f, ev.x, ev.y, 0, false, false);
+
+		    /* A window will be autoselected only when it is not
+		       selected now and the last mouse movement event was
+		       not in it.  The remainder of the code is a bit vague
+		       wrt what a "window" is.  For immediate autoselection,
+		       the window is usually the entire window but for GTK
+		       where the scroll bars don't count.  For delayed
+		       autoselection the window is usually the window's text
+		       area including the margins.  */
+		    if (WINDOWP (window)
+			&& !EQ (window, last_mouse_window)
+			&& !EQ (window, selected_window))
+		      {
+			inev.ie.kind = SELECT_WINDOW_EVENT;
+			inev.ie.frame_or_window = window;
+		      }
+
+		    /* Remember the last window where we saw the mouse.  */
+		    last_mouse_window = window;
+		  }
+
+		if (!x_note_mouse_movement (f, &ev))
+		  help_echo_string = previous_help_echo_string;
+	      }
+	    else
+	      {
+#ifndef USE_TOOLKIT_SCROLL_BARS
+		struct scroll_bar *bar
+		  = x_window_to_scroll_bar (xi_event->display, xev->event, 2);
+
+		if (bar)
+		  x_scroll_bar_note_movement (bar, &ev);
+#endif /* USE_TOOLKIT_SCROLL_BARS */
+
+		/* If we move outside the frame, then we're
+		   certainly no longer on any text in the frame.  */
+		clear_mouse_face (hlinfo);
+	      }
+
+	    /* If the contents of the global variable help_echo_string
+	       has changed, generate a HELP_EVENT.  */
+	    if (!NILP (help_echo_string)
+		|| !NILP (previous_help_echo_string))
+	      do_help = 1;
+	    goto XI_OTHER;
+	  case XI_ButtonRelease:
+	  case XI_ButtonPress:
+	    {
+	      /* If we decide we want to generate an event to be seen
+		 by the rest of Emacs, we put it here.  */
+	      Lisp_Object tab_bar_arg = Qnil;
+	      bool tab_bar_p = false;
+	      bool tool_bar_p = false;
+
+	      bv.button = xev->detail;
+	      bv.type = xev->evtype == XI_ButtonPress ? ButtonPress : ButtonRelease;
+	      bv.x = lrint (xev->event_x);
+	      bv.y = lrint (xev->event_y);
+	      bv.window = xev->event;
+	      bv.state = xev->mods.base
+		| xev->mods.effective
+		| xev->mods.latched
+		| xev->mods.locked;
+
+	      memset (&compose_status, 0, sizeof (compose_status));
+	      dpyinfo->last_mouse_glyph_frame = NULL;
+	      x_display_set_last_user_time (dpyinfo, xev->time);
+
+	      f = mouse_or_wdesc_frame (dpyinfo, xev->event);
+
+	      if (f && xev->evtype == XI_ButtonPress
+		  && !popup_activated ()
+		  && !x_window_to_scroll_bar (xev->display, xev->event, 2)
+		  && !FRAME_NO_ACCEPT_FOCUS (f))
+		{
+		  /* When clicking into a child frame or when clicking
+		     into a parent frame with the child frame selected and
+		     `no-accept-focus' is not set, select the clicked
+		     frame.  */
+		  struct frame *hf = dpyinfo->highlight_frame;
+
+		  if (FRAME_PARENT_FRAME (f) || (hf && frame_ancestor_p (f, hf)))
+		    {
+		      block_input ();
+		      XSetInputFocus (FRAME_X_DISPLAY (f), FRAME_OUTER_WINDOW (f),
+				      RevertToParent, CurrentTime);
+		      if (FRAME_PARENT_FRAME (f))
+			XRaiseWindow (FRAME_X_DISPLAY (f), FRAME_OUTER_WINDOW (f));
+		      unblock_input ();
+		    }
+		}
+
+#ifdef USE_GTK
+	      if (f && xg_event_is_for_scrollbar (f, event))
+		f = 0;
+#endif
+
+	      if (f)
+		{
+		  /* Is this in the tab-bar?  */
+		  if (WINDOWP (f->tab_bar_window)
+		      && WINDOW_TOTAL_LINES (XWINDOW (f->tab_bar_window)))
+		    {
+		      Lisp_Object window;
+		      int x = bv.x;
+		      int y = bv.y;
+
+		      window = window_from_coordinates (f, x, y, 0, true, true);
+		      tab_bar_p = EQ (window, f->tab_bar_window);
+
+		      if (tab_bar_p)
+			tab_bar_arg = handle_tab_bar_click
+			  (f, x, y, xev->evtype == XI_ButtonPress,
+			   x_x_to_emacs_modifiers (dpyinfo, bv.state));
+		    }
+
+#if ! defined (USE_GTK)
+		  /* Is this in the tool-bar?  */
+		  if (WINDOWP (f->tool_bar_window)
+		      && WINDOW_TOTAL_LINES (XWINDOW (f->tool_bar_window)))
+		    {
+		      Lisp_Object window;
+		      int x = bv.x;
+		      int y = bv.y;
+
+		      window = window_from_coordinates (f, x, y, 0, true, true);
+		      tool_bar_p = EQ (window, f->tool_bar_window);
+
+		      if (tool_bar_p && xev->detail < 4)
+			handle_tool_bar_click
+			  (f, x, y, xev->evtype == XI_ButtonPress,
+			   x_x_to_emacs_modifiers (dpyinfo, bv.state));
+		    }
+#endif /* !USE_GTK */
+
+		  if (!(tab_bar_p && NILP (tab_bar_arg)) && !tool_bar_p)
+#if defined (USE_X_TOOLKIT) || defined (USE_GTK)
+		    if (! popup_activated ())
+#endif
+		      {
+			if (ignore_next_mouse_click_timeout)
+			  {
+			    if (xev->evtype == XI_ButtonPress
+				&& xev->time > ignore_next_mouse_click_timeout)
+			      {
+				ignore_next_mouse_click_timeout = 0;
+				x_construct_mouse_click (&inev.ie, &bv, f);
+			      }
+			    if (xev->evtype == XI_ButtonRelease)
+			      ignore_next_mouse_click_timeout = 0;
+			  }
+			else
+			  x_construct_mouse_click (&inev.ie, &bv, f);
+
+			if (!NILP (tab_bar_arg))
+			  inev.ie.arg = tab_bar_arg;
+		      }
+		  if (FRAME_X_EMBEDDED_P (f))
+		    xembed_send_message (f, xev->time,
+					 XEMBED_REQUEST_FOCUS, 0, 0, 0);
+		}
+
+	      if (xev->evtype == XI_ButtonPress)
+		{
+		  dpyinfo->grabbed |= (1 << xev->detail);
+		  dpyinfo->last_mouse_frame = f;
+		  if (f && !tab_bar_p)
+		    f->last_tab_bar_item = -1;
+#if ! defined (USE_GTK)
+		  if (f && !tool_bar_p)
+		    f->last_tool_bar_item = -1;
+#endif /* not USE_GTK */
+
+		}
+	      else
+		dpyinfo->grabbed &= ~(1 << xev->detail);
+
+	      if (f)
+		f->mouse_moved = false;
+
+#if defined (USE_GTK)
+	      /* No Xt toolkit currently available has support for XI2.
+	         So the code here assumes use of GTK.  */
+	      f = x_menubar_window_to_frame (dpyinfo, event);
+	      if (f /* Gtk+ menus only react to the first three buttons. */
+		  && xev->detail < 3)
+		{
+		  /* What is done with Core Input ButtonPressed is not
+		     possible here, because GenericEvents cannot be saved.  */
+		  bool was_waiting_for_input = waiting_for_input;
+		  /* This hack was adopted from the NS port.  Whether
+		     or not it is actually safe is a different story
+		     altogether.  */
+		  if (waiting_for_input)
+		    waiting_for_input = 0;
+		  set_frame_menubar (f, true);
+		  waiting_for_input = was_waiting_for_input;
+		}
+#endif
+	      goto XI_OTHER;
+	    }
+	  case XI_KeyPress:
+	    {
+	      int state = xev->mods.base
+		| xev->mods.effective
+		| xev->mods.latched
+		| xev->mods.locked;
+	      Lisp_Object c;
+#ifdef HAVE_XKB
+	      unsigned int mods_rtrn;
+#endif
+	      int keycode = xev->detail;
+	      KeySym keysym;
+	      char copy_buffer[81];
+	      char *copy_bufptr = copy_buffer;
+	      unsigned char *copy_ubufptr;
+#ifdef HAVE_XKB
+	      int copy_bufsiz = sizeof (copy_buffer);
+#endif
+	      ptrdiff_t i;
+	      int nchars, len;
+
+#ifdef HAVE_XKB
+	      if (dpyinfo->xkb_desc)
+		{
+		  if (!XkbTranslateKeyCode (dpyinfo->xkb_desc, keycode,
+					    state, &mods_rtrn, &keysym))
+		    goto XI_OTHER;
+		}
+	      else
+		{
+#endif
+		  int keysyms_per_keycode_return;
+		  KeySym *ksms = XGetKeyboardMapping (dpyinfo->display, keycode, 1,
+						      &keysyms_per_keycode_return);
+		  if (!(keysym = ksms[0]))
+		    {
+		      XFree (ksms);
+		      goto XI_OTHER;
+		    }
+		  XFree (ksms);
+#ifdef HAVE_XKB
+		}
+#endif
+
+	      if (keysym == NoSymbol)
+		goto XI_OTHER;
+
+	      x_display_set_last_user_time (dpyinfo, xev->time);
+	      ignore_next_mouse_click_timeout = 0;
+
+#if defined (USE_X_TOOLKIT) || defined (USE_GTK)
+	      /* Dispatch XI_KeyPress events when in menu.  */
+	      if (popup_activated ())
+		goto XI_OTHER;
+#endif
+
+	      f = x_any_window_to_frame (dpyinfo, xev->event);
+
+	      /* If mouse-highlight is an integer, input clears out
+		 mouse highlighting.  */
+	      if (!hlinfo->mouse_face_hidden && FIXNUMP (Vmouse_highlight)
+		  && (f == 0
+#if ! defined (USE_GTK)
+		      || !EQ (f->tool_bar_window, hlinfo->mouse_face_window)
+#endif
+		      || !EQ (f->tab_bar_window, hlinfo->mouse_face_window))
+		  )
+		{
+		  clear_mouse_face (hlinfo);
+		  hlinfo->mouse_face_hidden = true;
+		}
+
+	      if (f != 0)
+		{
+		  /* If not using XIM/XIC, and a compose sequence is in progress,
+		     we break here.  Otherwise, chars_matched is always 0.  */
+		  if (compose_status.chars_matched > 0 && nbytes == 0)
+		    goto XI_OTHER;
+
+		  memset (&compose_status, 0, sizeof (compose_status));
+
+		  XSETFRAME (inev.ie.frame_or_window, f);
+		  inev.ie.modifiers
+		    = x_x_to_emacs_modifiers (FRAME_DISPLAY_INFO (f), state);
+		  inev.ie.timestamp = xev->time;
+
+		  /* First deal with keysyms which have defined
+		     translations to characters.  */
+		  if (keysym >= 32 && keysym < 128)
+		    /* Avoid explicitly decoding each ASCII character.  */
+		    {
+		      inev.ie.kind = ASCII_KEYSTROKE_EVENT;
+		      inev.ie.code = keysym;
+
+		      goto xi_done_keysym;
+		    }
+
+		  /* Keysyms directly mapped to Unicode characters.  */
+		  if (keysym >= 0x01000000 && keysym <= 0x0110FFFF)
+		    {
+		      if (keysym < 0x01000080)
+			inev.ie.kind = ASCII_KEYSTROKE_EVENT;
+		      else
+			inev.ie.kind = MULTIBYTE_CHAR_KEYSTROKE_EVENT;
+		      inev.ie.code = keysym & 0xFFFFFF;
+		      goto xi_done_keysym;
+		    }
+
+		  /* Now non-ASCII.  */
+		  if (HASH_TABLE_P (Vx_keysym_table)
+		      && (c = Fgethash (make_fixnum (keysym),
+					Vx_keysym_table,
+					Qnil),
+			  FIXNATP (c)))
+		    {
+		      inev.ie.kind = (SINGLE_BYTE_CHAR_P (XFIXNAT (c))
+				      ? ASCII_KEYSTROKE_EVENT
+				      : MULTIBYTE_CHAR_KEYSTROKE_EVENT);
+		      inev.ie.code = XFIXNAT (c);
+		      goto xi_done_keysym;
+		    }
+
+		  /* Random non-modifier sorts of keysyms.  */
+		  if (((keysym >= XK_BackSpace && keysym <= XK_Escape)
+		       || keysym == XK_Delete
+#ifdef XK_ISO_Left_Tab
+		       || (keysym >= XK_ISO_Left_Tab
+			   && keysym <= XK_ISO_Enter)
+#endif
+		       || IsCursorKey (keysym) /* 0xff50 <= x < 0xff60 */
+		       || IsMiscFunctionKey (keysym) /* 0xff60 <= x < VARIES */
+#ifdef HPUX
+		       /* This recognizes the "extended function
+			  keys".  It seems there's no cleaner way.
+			  Test IsModifierKey to avoid handling
+			  mode_switch incorrectly.  */
+		       || (XK_Select <= keysym && keysym < XK_KP_Space)
+#endif
+#ifdef XK_dead_circumflex
+		       || keysym == XK_dead_circumflex
+#endif
+#ifdef XK_dead_grave
+		       || keysym == XK_dead_grave
+#endif
+#ifdef XK_dead_tilde
+		       || keysym == XK_dead_tilde
+#endif
+#ifdef XK_dead_diaeresis
+		       || keysym == XK_dead_diaeresis
+#endif
+#ifdef XK_dead_macron
+		       || keysym == XK_dead_macron
+#endif
+#ifdef XK_dead_degree
+		       || keysym == XK_dead_degree
+#endif
+#ifdef XK_dead_acute
+		       || keysym == XK_dead_acute
+#endif
+#ifdef XK_dead_cedilla
+		       || keysym == XK_dead_cedilla
+#endif
+#ifdef XK_dead_breve
+		       || keysym == XK_dead_breve
+#endif
+#ifdef XK_dead_ogonek
+		       || keysym == XK_dead_ogonek
+#endif
+#ifdef XK_dead_caron
+		       || keysym == XK_dead_caron
+#endif
+#ifdef XK_dead_doubleacute
+		       || keysym == XK_dead_doubleacute
+#endif
+#ifdef XK_dead_abovedot
+		       || keysym == XK_dead_abovedot
+#endif
+		       || IsKeypadKey (keysym) /* 0xff80 <= x < 0xffbe */
+		       || IsFunctionKey (keysym) /* 0xffbe <= x < 0xffe1 */
+		       /* Any "vendor-specific" key is ok.  */
+		       || (keysym & (1 << 28))
+		       || (keysym != NoSymbol && nbytes == 0))
+		      && ! (IsModifierKey (keysym)
+			    /* The symbols from XK_ISO_Lock
+			       to XK_ISO_Last_Group_Lock
+			       don't have real modifiers but
+			       should be treated similarly to
+			       Mode_switch by Emacs. */
+#if defined XK_ISO_Lock && defined XK_ISO_Last_Group_Lock
+			    || (XK_ISO_Lock <= keysym
+				&& keysym <= XK_ISO_Last_Group_Lock)
+#endif
+			    ))
+		    {
+		      STORE_KEYSYM_FOR_DEBUG (keysym);
+		      /* make_lispy_event will convert this to a symbolic
+			 key.  */
+		      inev.ie.kind = NON_ASCII_KEYSTROKE_EVENT;
+		      inev.ie.code = keysym;
+		      goto xi_done_keysym;
+		    }
+
+#ifdef HAVE_XKB
+		  int overflow = 0;
+		  KeySym sym = keysym;
+
+		  if (dpyinfo->xkb_desc)
+		    {
+		      if (!(nbytes = XkbTranslateKeySym (dpyinfo->display, &sym,
+							 state & ~mods_rtrn, copy_bufptr,
+							 copy_bufsiz, &overflow)))
+			goto XI_OTHER;
+		    }
+		  else
+#else
+		    {
+		      block_input ();
+		      char *str = XKeysymToString (keysym);
+		      if (!str)
+			{
+			  unblock_input ();
+			  goto XI_OTHER;
+			}
+		      nbytes = strlen (str) + 1;
+		      copy_bufptr = alloca (nbytes);
+		      strcpy (copy_bufptr, str);
+		      unblock_input ();
+		    }
+#endif
+#ifdef HAVE_XKB
+		  if (overflow)
+		    {
+		      overflow = 0;
+		      copy_bufptr = alloca (copy_bufsiz + overflow);
+		      keysym = sym;
+		      if (!(nbytes = XkbTranslateKeySym (dpyinfo->display, &sym,
+							 state & ~mods_rtrn, copy_bufptr,
+							 copy_bufsiz + overflow, &overflow)))
+			goto XI_OTHER;
+
+		      if (overflow)
+			goto XI_OTHER;
+		    }
+#endif
+
+		  for (i = 0, nchars = 0; i < nbytes; i++)
+		    {
+		      if (ASCII_CHAR_P (copy_bufptr[i]))
+			nchars++;
+		      STORE_KEYSYM_FOR_DEBUG (copy_bufptr[i]);
+		    }
+
+		  if (nchars < nbytes)
+		    {
+		      /* Decode the input data.  */
+
+		      setup_coding_system (Vlocale_coding_system, &coding);
+		      coding.src_multibyte = false;
+		      coding.dst_multibyte = true;
+		      /* The input is converted to events, thus we can't
+			 handle composition.  Anyway, there's no XIM that
+			 gives us composition information.  */
+		      coding.common_flags &= ~CODING_ANNOTATION_MASK;
+
+		      SAFE_NALLOCA (coding.destination, MAX_MULTIBYTE_LENGTH,
+				    nbytes);
+		      coding.dst_bytes = MAX_MULTIBYTE_LENGTH * nbytes;
+		      coding.mode |= CODING_MODE_LAST_BLOCK;
+		      decode_coding_c_string (&coding, (unsigned char *) copy_bufptr, nbytes, Qnil);
+		      nbytes = coding.produced;
+		      nchars = coding.produced_char;
+		      copy_bufptr = (char *) coding.destination;
+		    }
+
+		  copy_ubufptr = (unsigned char *) copy_bufptr;
+
+		  /* Convert the input data to a sequence of
+		     character events.  */
+		  for (i = 0; i < nbytes; i += len)
+		    {
+		      int ch;
+		      if (nchars == nbytes)
+			ch = copy_ubufptr[i], len = 1;
+		      else
+			ch = string_char_and_length (copy_ubufptr + i, &len);
+		      inev.ie.kind = (SINGLE_BYTE_CHAR_P (ch)
+				      ? ASCII_KEYSTROKE_EVENT
+				      : MULTIBYTE_CHAR_KEYSTROKE_EVENT);
+		      inev.ie.code = ch;
+		      kbd_buffer_store_buffered_event (&inev, hold_quit);
+		    }
+
+		  inev.ie.kind = NO_EVENT;
+		  goto xi_done_keysym;
+		}
+	      goto XI_OTHER;
+	    }
+	  case XI_KeyRelease:
+	    x_display_set_last_user_time (dpyinfo, xev->time);
+	    goto XI_OTHER;
+	  case XI_PropertyEvent:
+
+	  default:
+	    goto XI_OTHER;
+	  }
+      xi_done_keysym:
+	if (must_free_data)
+	  XFreeEventData (dpyinfo->display, &event->xcookie);
+	goto done_keysym;
+      XI_OTHER:
+	if (must_free_data)
+	  XFreeEventData (dpyinfo->display, &event->xcookie);
+	goto OTHER;
+      }
+#endif
 
     default:
     OTHER:
@@ -13013,6 +13745,35 @@ #define NUM_ARGV 10
     dpyinfo->supports_xdbe = true;
 #endif
 
+#ifdef HAVE_XINPUT2
+  dpyinfo->supports_xi2 = false;
+  int rc;
+  int major = 2;
+#ifdef XI_BarrierHit /* XInput 2.3 */
+  int minor = 3;
+#elif defined XI_TouchBegin /* XInput 2.2 */
+  int minor = 2;
+#else /* Some old version of XI2 we're not interested in. */
+  int minor = 0;
+#endif
+  int fer, fee;
+
+  if (XQueryExtension (dpyinfo->display, "XInputExtension",
+		       &dpyinfo->xi2_opcode, &fer, &fee))
+    {
+      rc = XIQueryVersion (dpyinfo->display, &major, &minor);
+      if (rc == Success)
+	dpyinfo->supports_xi2 = true;
+    }
+  dpyinfo->xi2_version = minor;
+#endif
+
+#ifdef HAVE_XKB
+  dpyinfo->xkb_desc = XkbGetMap (dpyinfo->display,
+				 XkbAllComponentsMask,
+				 XkbUseCoreKbd);
+#endif
+
 #if defined USE_CAIRO || defined HAVE_XFT
   {
     /* If we are using Xft, the following precautions should be made:
@@ -13445,6 +14206,10 @@ x_delete_terminal (struct terminal *terminal)
       XrmDestroyDatabase (dpyinfo->rdb);
 #endif
 
+#ifdef HAVE_XKB
+      if (dpyinfo->xkb_desc)
+	XkbFreeKeyboard (dpyinfo->xkb_desc, XkbAllComponentsMask, True);
+#endif
 #ifdef USE_GTK
       xg_display_close (dpyinfo->display);
 #else
@@ -13604,9 +14369,12 @@ x_initialize (void)
 void
 init_xterm (void)
 {
-  /* Emacs can handle only core input events, so make sure
-     Gtk doesn't use Xinput or Xinput2 extensions.  */
+#ifndef HAVE_XINPUT2
+  /* Emacs can handle only core input events when built without XI2
+     support, so make sure Gtk doesn't use Xinput or Xinput2
+     extensions.  */
   xputenv ("GDK_CORE_DEVICE_EVENTS=1");
+#endif
 }
 #endif
 
diff --git a/src/xterm.h b/src/xterm.h
index de6ea50385..6d5f28c76e 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -88,6 +88,10 @@ #define XSync(d, b) do { gdk_window_process_all_updates (); \
 #include <X11/Xlib-xcb.h>
 #endif
 
+#ifdef HAVE_XKB
+#include <X11/XKBlib.h>
+#endif
+
 #include "dispextern.h"
 #include "termhooks.h"
 
@@ -474,6 +478,16 @@ #define MAX_CLIP_RECTS 2
 #ifdef HAVE_XDBE
   bool supports_xdbe;
 #endif
+
+#ifdef HAVE_XINPUT2
+  bool supports_xi2;
+  int xi2_version;
+  int xi2_opcode;
+#endif
+
+#ifdef HAVE_XKB
+  XkbDescPtr xkb_desc;
+#endif
 };
 
 #ifdef HAVE_X_I18N
-- 
2.31.1