From bf5c75465f37ad45934f58287660f18ec0bcf7bf Mon Sep 17 00:00:00 2001
From: Po Lu <luangruo@yahoo.com>
Date: Fri, 24 Jun 2022 10:57:35 +0800
Subject: [PATCH] Improve grabbing detection with multiple master devices (MPX)

* src/frame.c (gui_mouse_grabbed): Respect any_grab_hook.
* src/termhooks.h (GCALIGNED_STRUCT): New hook `any_grab_hook'.
* src/xterm.c (x_have_any_grab): New function.
(x_create_terminal): Define hook on XI2 builds.
---
 src/frame.c     |  4 +++-
 src/termhooks.h |  7 +++++++
 src/xterm.c     | 22 ++++++++++++++++++++++
 3 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/src/frame.c b/src/frame.c
index c2f2f8e4642..02c90ea6519 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -5130,7 +5130,9 @@ gui_set_no_special_glyphs (struct frame *f, Lisp_Object new_value, Lisp_Object o
 bool
 gui_mouse_grabbed (Display_Info *dpyinfo)
 {
-  return (dpyinfo->grabbed
+  return ((dpyinfo->grabbed
+	   || (dpyinfo->terminal->any_grab_hook
+	       && dpyinfo->terminal->any_grab_hook (dpyinfo)))
 	  && dpyinfo->last_mouse_frame
 	  && FRAME_LIVE_P (dpyinfo->last_mouse_frame));
 }
diff --git a/src/termhooks.h b/src/termhooks.h
index d7190e77362..a1e3e2cde9a 100644
--- a/src/termhooks.h
+++ b/src/termhooks.h
@@ -877,6 +877,13 @@ struct terminal
      MENU_BAR_P if X and Y are in FRAME's toolkit menu bar, and true
      into TOOL_BAR_P if X and Y are in FRAME's toolkit tool bar.  */
   void (*toolkit_position_hook) (struct frame *, int, int, bool *, bool *);
+
+#ifdef HAVE_WINDOW_SYSTEM
+  /* Called to determine if the mouse is grabbed on the given display.
+     If either dpyinfo->grabbed or this returns true, then the display
+     will be considered as grabbed.  */
+  bool (*any_grab_hook) (Display_Info *);
+#endif
 } GCALIGNED_STRUCT;
 
 INLINE bool
diff --git a/src/xterm.c b/src/xterm.c
index 6375b71666b..414a9c0ebed 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -27320,6 +27320,25 @@ x_delete_terminal (struct terminal *terminal)
   unblock_input ();
 }
 
+#ifdef HAVE_XINPUT2
+static bool
+x_have_any_grab (struct x_display_info *dpyinfo)
+{
+  int i;
+
+  if (!dpyinfo->supports_xi2)
+    return false;
+
+  for (i = 0; i < dpyinfo->num_devices; ++i)
+    {
+      if (dpyinfo->devices[i].grab)
+	return true;
+    }
+
+  return false;
+}
+#endif
+
 /* Create a struct terminal, initialize it with the X11 specific
    functions and make DISPLAY->TERMINAL point to it.  */
 
@@ -27387,6 +27406,9 @@ x_create_terminal (struct x_display_info *dpyinfo)
   terminal->delete_frame_hook = x_destroy_window;
   terminal->delete_terminal_hook = x_delete_terminal;
   terminal->toolkit_position_hook = x_toolkit_position;
+#ifdef HAVE_XINPUT2
+  terminal->any_grab_hook = x_have_any_grab;
+#endif
   /* Other hooks are NULL by default.  */
 
   return terminal;
-- 
2.39.2