interface/wlr_switch: rework destroy sequence

The destroy callback in wlr_switch_impl has been removed. The function
`wlr_switch_finish` has been introduced to clean up the resources owned by a
wlr_switch.

`wlr_input_device_destroy` no longer destroys the wlr_switch, attempting to
destroy a wlr_switch will result in a no-op.

The field `name` has been added to the wlr_switch_impl to be able to identify
a given wlr_switch device.

backend/libinput/events.c

@@ -21,7 +21,7 @@ void destroy_libinput_input_device(struct wlr_libinput_input_device *dev) {
 		wlr_pointer_finish(&dev->pointer);
 	}
 	if (dev->switch_device.impl) {
-		wlr_switch_destroy(&dev->switch_device);
+		wlr_switch_finish(&dev->switch_device);
 	}
 	if (dev->touch.impl) {
 		wlr_touch_destroy(&dev->touch);

backend/libinput/switch.c

@@ -4,12 +4,8 @@
 #include "backend/libinput.h"
 #include "util/signal.h"
 
-static void switch_destroy(struct wlr_switch *wlr_switch) {
-	/* wlr_switch belongs to the wlr_libinput_input_device */
-}
-
 const struct wlr_switch_impl libinput_switch_impl = {
-	.destroy = switch_destroy,
+	.name = "libinput-switch",
 };
 
 void init_device_switch(struct wlr_libinput_input_device *dev) {

backend/wayland/seat.c

@@ -12,6 +12,7 @@
 #include <wlr/interfaces/wlr_keyboard.h>
 #include <wlr/interfaces/wlr_output.h>
 #include <wlr/interfaces/wlr_pointer.h>
+#include <wlr/interfaces/wlr_switch.h>
 #include <wlr/interfaces/wlr_touch.h>
 #include <wlr/interfaces/wlr_tablet_tool.h>
 #include <wlr/interfaces/wlr_tablet_pad.h>
@@ -555,6 +556,9 @@ void destroy_wl_input_device(struct wlr_wl_input_device *dev) {
 			/* Owned by wlr_wl_pointer */
 			pointer_destroy(wlr_dev->pointer);
 			break;
+		case WLR_INPUT_DEVICE_SWITCH:
+			wlr_switch_finish(wlr_dev->switch_device);
+			break;
 		default:
 			wlr_input_device_destroy(wlr_dev);
 			break;

include/wlr/interfaces/wlr_switch.h

@@ -12,11 +12,11 @@
 #include <wlr/types/wlr_switch.h>
 
 struct wlr_switch_impl {
-	void (*destroy)(struct wlr_switch *switch_device);
+	const char *name;
 };
 
 void wlr_switch_init(struct wlr_switch *switch_device,
 	const struct wlr_switch_impl *impl, const char *name);
-void wlr_switch_destroy(struct wlr_switch *switch_device);
+void wlr_switch_finish(struct wlr_switch *switch_device);
 
 #endif

types/wlr_input_device.c

@@ -2,7 +2,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <wayland-server-core.h>
-#include <wlr/interfaces/wlr_switch.h>
 #include <wlr/interfaces/wlr_tablet_pad.h>
 #include <wlr/interfaces/wlr_tablet_tool.h>
 #include <wlr/interfaces/wlr_touch.h>
@@ -45,7 +44,7 @@ void wlr_input_device_destroy(struct wlr_input_device *dev) {
 			wlr_log(WLR_ERROR, "wlr_pointer will not be destroyed");
 			break;
 		case WLR_INPUT_DEVICE_SWITCH:
-			wlr_switch_destroy(dev->switch_device);
+			wlr_log(WLR_ERROR, "wlr_switch will not be destroyed");
 			break;
 		case WLR_INPUT_DEVICE_TOUCH:
 			wlr_touch_destroy(dev->touch);

types/wlr_switch.c

@@ -13,14 +13,6 @@ void wlr_switch_init(struct wlr_switch *switch_device,
 	wl_signal_init(&switch_device->events.toggle);
 }
 
-void wlr_switch_destroy(struct wlr_switch *switch_device) {
-	if (!switch_device) {
-		return;
-	}
+void wlr_switch_finish(struct wlr_switch *switch_device) {
 	wlr_input_device_finish(&switch_device->base);
-	if (switch_device->impl && switch_device->impl->destroy) {
-		switch_device->impl->destroy(switch_device);
-	} else {
-		free(switch_device);
-	}
 }