rootston: add arbitrary libinput config 'tap_enabled'

This ought to be enough to serve as an example for other compositors to
use.

include/rootston/config.h

@@ -21,6 +21,7 @@ struct roots_device_config {
 	char *name;
 	char *seat;
 	char *mapped_output;
+	bool tap_enabled;
 	struct wlr_box *mapped_box;
 	struct wl_list link;
 };

rootston/config.c

@@ -342,6 +342,16 @@ static int config_ini_handler(void *user, const char *section, const char *name,
 		} else if (strcmp(name, "seat") == 0) {
 			free(dc->seat);
 			dc->seat = strdup(value);
+		} else if (strcmp(name, "tap_enabled") == 0) {
+			if (strcasecmp(value, "true") == 0) {
+				dc->tap_enabled = true;
+			} else if (strcasecmp(value, "false") == 0) {
+				dc->tap_enabled = false;
+			} else {
+				wlr_log(L_ERROR,
+					"got unknown tap_enabled value: %s",
+					value);
+			}
 		} else {
 			wlr_log(L_ERROR, "got unknown device config: %s", name);
 		}

rootston/input.c

@@ -5,6 +5,7 @@
 #include <wlr/util/log.h>
 #include <wlr/xcursor.h>
 #include <wlr/xwayland.h>
+#include <wlr/backend/libinput.h>
 #include "rootston/server.h"
 #include "rootston/config.h"
 #include "rootston/input.h"
@@ -60,6 +61,17 @@ static void input_add_notify(struct wl_listener *listener, void *data) {
 			device->vendor, device->product, device_type(device->type), seat_name);
 
 	roots_seat_add_device(seat, device);
+
+	if (dc && wlr_input_device_is_libinput(device)) {
+		struct libinput_device *libinput_dev =
+			wlr_libinput_get_device_handle(device);
+
+		wlr_log(L_DEBUG, "input has config, tap_enabled: %d\n", dc->tap_enabled);
+		if (dc->tap_enabled) {
+			libinput_device_config_tap_set_enabled(libinput_dev,
+					LIBINPUT_CONFIG_TAP_ENABLED);
+		}
+	}
 }
 
 static void input_remove_notify(struct wl_listener *listener, void *data) {

rootston/rootston.ini.example

@@ -30,6 +30,7 @@ theme = default
 map-to-output = VGA-1
 # Restrict cursor movements for this mouse to concrete rectangle
 geometry = 2500x800
+# tap_enabled=true
 
 [keyboard]
 meta-key = Logo