From 0219f8e1af24844189b6f3ac3af7f11379fd3a94 Mon Sep 17 00:00:00 2001
From: Jared Finder <jared@finder.org>
Date: Sat, 23 Jan 2021 16:53:43 -0800
Subject: [PATCH 2/3] Support 'mouse-autoselect-window' for GPM and xterm mouse

* src/dispnew.c (update_mouse_position): Generate SELECT_WINDOW_EVENT.
---
 src/dispnew.c  | 32 ++++++++++++++++++++++++++++++--
 src/msdos.c    |  1 +
 src/nsterm.m   |  1 +
 src/w32inevt.c |  1 +
 src/w32term.c  |  1 +
 src/xterm.c    |  1 +
 6 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/dispnew.c b/src/dispnew.c
index e603c67136..5dc4ac24db 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -3335,11 +3335,39 @@ update_frame_with_menu (struct frame *f, int row, int col)
 int
 update_mouse_position (struct frame *f, int x, int y)
 {
+  int event_count = 0;
+
   previous_help_echo_string = help_echo_string;
   help_echo_string = Qnil;
 
   note_mouse_highlight (f, x, y);
 
+  /* When the mouse moves over a new window, generate a
+     SELECT_WINDOW_EVENT.  */
+  if (!NILP (Vmouse_autoselect_window))
+    {
+      static Lisp_Object last_mouse_window;
+      Lisp_Object window = window_from_coordinates (f, x, y, 0, 0, 0);
+
+      /* Window will be selected only when it is not selected now and
+	 last mouse movement event was not in it.  Minibuffer window
+	 will be selected only when it is active.  */
+      if (WINDOWP (window)
+	  && !EQ (window, last_mouse_window)
+	  && !EQ (window, selected_window))
+	{
+	  struct input_event event;
+	  EVENT_INIT (event);
+	  event.kind = SELECT_WINDOW_EVENT;
+	  event.frame_or_window = window;
+	  kbd_buffer_store_event (&event);
+	  ++event_count;
+	}
+
+      /* Remember the last window where we saw the mouse.  */
+      last_mouse_window = window;
+    }
+
   /* If the contents of the global variable help_echo_string
      has changed, generate a HELP_EVENT.  */
   if (!NILP (help_echo_string)
@@ -3350,10 +3378,10 @@ update_mouse_position (struct frame *f, int x, int y)
 
       gen_help_event (help_echo_string, frame, help_echo_window,
                       help_echo_object, help_echo_pos);
-      return 1;
+      ++event_count;
     }
 
-  return 0;
+  return event_count;
 }
 
 DEFUN ("display--update-for-mouse-movement", Fdisplay__update_for_mouse_movement,
diff --git a/src/msdos.c b/src/msdos.c
index 5da01c9e7c..0dab89d9df 100644
--- a/src/msdos.c
+++ b/src/msdos.c
@@ -2639,6 +2639,7 @@ dos_rawgetc (void)
       /* Check for mouse movement *before* buttons.  */
       mouse_check_moved ();
 
+      /* FIXME: Combine this logic with update_mouse_position.  */
       /* If the mouse moved from the spot of its last sighting, we
          might need to update mouse highlight.  */
       if (mouse_last_x != mouse_prev_x || mouse_last_y != mouse_prev_y)
diff --git a/src/nsterm.m b/src/nsterm.m
index 1b2328628e..60acda1bcd 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -7037,6 +7037,7 @@ - (void) scrollWheel: (NSEvent *)theEvent
 }
 
 
+/* FIXME: Combine this logic with update_mouse_position.  */
 /* Tell emacs the mouse has moved.  */
 - (void)mouseMoved: (NSEvent *)e
 {
diff --git a/src/w32inevt.c b/src/w32inevt.c
index 1a80a00197..383169c3d1 100644
--- a/src/w32inevt.c
+++ b/src/w32inevt.c
@@ -473,6 +473,7 @@ do_mouse_event (MOUSE_EVENT_RECORD *event,
   switch (flags)
     {
     case MOUSE_MOVED:
+      /* FIXME: Combine this logic with update_mouse_position.  */
       {
 	struct frame *f = get_frame ();
 	Mouse_HLInfo *hlinfo = MOUSE_HL_INFO (f);
diff --git a/src/w32term.c b/src/w32term.c
index 0ee805a852..7e9b641414 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -5083,6 +5083,7 @@ w32_read_socket (struct terminal *terminal,
 	  break;
 
 	case WM_MOUSEMOVE:
+	  /* FIXME: Combine this logic with update_mouse_position.  */
 	  /* Ignore non-movement.  */
 	  {
 	    int x = LOWORD (msg.msg.lParam);
diff --git a/src/xterm.c b/src/xterm.c
index 744b80c68a..d9fb389f89 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -8830,6 +8830,7 @@ handle_one_xevent (struct x_display_info *dpyinfo,
       goto OTHER;
 
     case MotionNotify:
+      /* FIXME: Combine this logic with update_mouse_position.  */
       {
         x_display_set_last_user_time (dpyinfo, event->xmotion.time);
         previous_help_echo_string = help_echo_string;
-- 
2.20.1