RandR: handle monitor {dis,}connection better

configure.ac

@@ -86,7 +86,7 @@ if test ! x"$with_golang" = xno; then
 		sed -e 's/ .*$//')
 	    AC_MSG_CHECKING([whether go version is >= 1.14.x ($go_version)])
 	    case "$go_version" in
-	     1.14*|1.15*|1.16*|1.17*|1.18*|1.19*|1.20*|1.21*)
+	     1.14*|1.15*|1.16*|1.17*|1.18*|1.19*|1.20*|1.21*|1.22*|1.23*)
 	      AC_MSG_RESULT([yes - version is: $go_version])
 	      with_golang="yes"
 	      GO=

fvwm/builtins.c

@@ -165,6 +165,9 @@ status_send(void)
 		if ((desk_doc[d_count] = cJSON_CreateObject()) == NULL)
 			goto out;
 
+		if (m->Desktops == NULL)
+			goto out;
+
 		this_desktop = cJSON_AddObjectToObject(desk_doc[d_count],
 		    "desktops");
 

fvwm/events.c

@@ -1774,7 +1774,7 @@ static void _refocus_stolen_focus_win(const evh_args_t *ea)
 void monitor_update_ewmh(void)
 {
 	FvwmWindow	*t;
-	struct monitor	*m, *mref;
+	struct monitor	*m, *mref, *mo, *mo1;
 
 	fvwm_debug(__func__, "monitor debug...\n");
 	if (Scr.bo.do_debug_randr)
@@ -1785,6 +1785,23 @@ void monitor_update_ewmh(void)
 	mref = RB_MIN(monitors, &monitor_q);
 
 	RB_FOREACH(m, monitors, &monitor_q) {
+		if (m->flags & MONITOR_CHANGED) {
+			if (changed_monitor_count() == 1)
+				goto out;
+			TAILQ_FOREACH(mo, &monitorsold_q, oentry) {
+				if (strcmp(m->si->name, mo->si->name) != 0)
+					continue;
+				if (mo->Desktops == NULL)
+					continue;
+				for (t = Scr.FvwmRoot.next; t; t = t->next) {
+					if (t->m == mo) {
+						t->m = m;
+						update_fvwm_monitor(t);
+					}
+				}
+			}
+			continue;
+		}
 		if (m->flags & MONITOR_NEW) {
 			if (m->Desktops == NULL) {
 				int ewbs[4] = {0, 0, 0, 0};
@@ -1795,6 +1812,9 @@ void monitor_update_ewmh(void)
 				m->Desktops->desk = 0;
 				apply_desktops_monitor(m);
 
+				if (m->Desktops->next == mref->Desktops->next)
+					continue;
+
 				calculate_page_sizes(m, mref->dx, mref->dy);
 
 				fvwm_debug(__func__,
@@ -1813,6 +1833,14 @@ void monitor_update_ewmh(void)
 		EWMH_Init(m);
 	}
 
+out:
+	TAILQ_FOREACH_SAFE(mo, &monitorsold_q, oentry, mo1) {
+		TAILQ_REMOVE(&monitorsold_q, mo, oentry);
+		fvwm_debug(__func__, "Removed mo '%s' from processing",
+		    mo->si->name);
+	}
+
+
 	BroadcastMonitorList(NULL);
 
 	for (t = Scr.FvwmRoot.next; t; t = t->next) {
@@ -1861,6 +1889,7 @@ monitor_emit_broadcast(void)
 				break;
 
 			if (pm != mnew) {
+				fvwm_debug(__func__, "MONITOR PRIMARY");
 				execute_function_override_window(
 				    NULL, NULL, randrfunc, NULL, 0, NULL);
 			}
@@ -2266,6 +2295,12 @@ void HandleEnterNotify(const evh_args_t *ea)
 		pfm = monitor_resolve_name(prev_focused_monitor);
 		this_m = monitor_get_current();
 
+		/* Don't toggle the previous monitor if there isn't one, or
+		 * the two monitors are the same.
+		 */
+		if ((pfm == NULL) || (pfm == this_m))
+			return;
+
 		/* Send MX_MONITOR_FOCUS event. */
 		toggle_prev_monitor_state(this_m, pfm, NULL);
 

libs/FScreen.c

@@ -56,6 +56,7 @@ enum monitor_tracking monitor_mode;
 bool			 is_tracking_shared;
 struct screen_infos	 screen_info_q, screen_info_q_temp;
 struct monitors		 monitor_q;
+struct monitorsold	 monitorsold_q;
 int randr_event;
 const char *prev_focused_monitor;
 static struct monitor	*monitor_global = NULL;
@@ -338,6 +339,17 @@ monitor_by_last_primary(void)
 	return (m);
 }
 
+int changed_monitor_count(void)
+{
+	struct monitor	*m;
+	int c = 0;
+
+	TAILQ_FOREACH(m, &monitorsold_q, oentry)
+		c++;
+
+	return (c);
+}
+
 static void
 monitor_check_primary(void)
 {
@@ -431,8 +443,10 @@ monitor_output_change(Display *dpy, XRRScreenChangeNotifyEvent *e)
 
 			if (oinfo->connection == RR_Connected &&
 			    m->flags & MONITOR_ENABLED) {
-				if (m->flags & MONITOR_CHANGED)
+				if (m->flags & MONITOR_CHANGED) {
 					m->emit |= MONITOR_CHANGED;
+					TAILQ_INSERT_TAIL(&monitorsold_q, m, oentry);
+				}
 				continue;
 			}
 
@@ -600,6 +614,9 @@ void FScreenInit(Display *dpy)
 	if (TAILQ_EMPTY(&screen_info_q))
 		TAILQ_INIT(&screen_info_q);
 
+	if (TAILQ_EMPTY(&monitorsold_q))
+		TAILQ_INIT(&monitorsold_q);
+
 	if (!XRRQueryExtension(dpy, &randr_event, &err_base) ||
 	    !XRRQueryVersion (dpy, &major, &minor)) {
 		fvwm_debug(__func__, "RandR not present");

libs/FScreen.h

@@ -145,14 +145,18 @@ struct monitor {
 	bool pan_frames_mapped;
 
 	RB_ENTRY(monitor) entry;
+	TAILQ_ENTRY(monitor) oentry;
 };
 RB_HEAD(monitors, monitor);
+TAILQ_HEAD(monitorsold, monitor);
 
 extern struct monitors  monitors;
 extern struct monitors	monitor_q;
+extern struct monitorsold  monitorsold_q;
 int			monitor_compare(struct monitor *, struct monitor *);
 RB_PROTOTYPE(monitors, monitor, entry, monitor_compare);
 
+int		 changed_monitor_count(void);
 struct monitor	*monitor_resolve_name(const char *);
 struct monitor	*monitor_by_xy(int, int);
 struct monitor  *monitor_by_output(int);