text: #define _POSIX_C_SOURCE 200809L
  
  #include <assert.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <string.h>
  #include <time.h>
  #include <unistd.h>
  
  #include <wayland-client.h>
  
  #include <wlr/interfaces/wlr_input_device.h>
  #include <wlr/interfaces/wlr_keyboard.h>
  #include <wlr/interfaces/wlr_output.h>
  #include <wlr/interfaces/wlr_pointer.h>
  #include <wlr/interfaces/wlr_touch.h>
  #include <wlr/util/log.h>
  
  #include "pointer-gestures-unstable-v1-client-protocol.h"
  #include "relative-pointer-unstable-v1-client-protocol.h"
  #include "backend/wayland.h"
  #include "util/signal.h"
  #include "util/time.h"
  
  static struct wlr_wl_pointer *output_get_pointer(struct wlr_wl_output *output) {
  	struct wlr_input_device *wlr_dev;
  	wl_list_for_each(wlr_dev, &output->backend->devices, link) {
  		if (wlr_dev->type != WLR_INPUT_DEVICE_POINTER) {
  			continue;
  		}
  		struct wlr_wl_pointer *pointer = pointer_get_wl(wlr_dev->pointer);
  		if (pointer->output == output) {
  			return pointer;
  		}
  	}
  
  	return NULL;
  }
  
  static void pointer_handle_enter(void *data, struct wl_pointer *wl_pointer,
  		uint32_t serial, struct wl_surface *surface, wl_fixed_t sx,
  		wl_fixed_t sy) {
  	struct wlr_wl_backend *backend = data;
  	if (surface == NULL) {
  		return;
  	}
  
  	struct wlr_wl_output *output = wl_surface_get_user_data(surface);
  	assert(output);
  	struct wlr_wl_pointer *pointer = output_get_pointer(output);
  
  	output->enter_serial = serial;
  	backend->current_pointer = pointer;
  	update_wl_output_cursor(output);
  }
  
  static void pointer_handle_leave(void *data, struct wl_pointer *wl_pointer,
  		uint32_t serial, struct wl_surface *surface) {
  	struct wlr_wl_backend *backend = data;
  	if (surface == NULL) {
  		return;
  	}
  
  	struct wlr_wl_output *output = wl_surface_get_user_data(surface);
  	assert(output);
  	output->enter_serial = 0;
  
  	if (backend->current_pointer == NULL ||
  			backend->current_pointer->output != output) {
  		return;
  	}
  
  	backend->current_pointer = NULL;
  }
  
  static void pointer_handle_motion(void *data, struct wl_pointer *wl_pointer,
  		uint32_t time, wl_fixed_t sx, wl_fixed_t sy) {
  	struct wlr_wl_backend *backend = data;
  	struct wlr_wl_pointer *pointer = backend->current_pointer;
  	if (pointer == NULL) {
  		return;
  	}
  
  	struct wlr_output *wlr_output = &pointer->output->wlr_output;
  	struct wlr_event_pointer_motion_absolute event = {
  		.device = &pointer->input_device->wlr_input_device,
  		.time_msec = time,
  		.x = wl_fixed_to_double(sx) / wlr_output->width,
  		.y = wl_fixed_to_double(sy) / wlr_output->height,
  	};
  	wlr_signal_emit_safe(&pointer->wlr_pointer.events.motion_absolute, &event);
  }
  
  static void pointer_handle_button(void *data, struct wl_pointer *wl_pointer,
  		uint32_t serial, uint32_t time, uint32_t button, uint32_t state) {
  	struct wlr_wl_backend *backend = data;
  	struct wlr_wl_pointer *pointer = backend->current_pointer;
  	if (pointer == NULL) {
  		return;
  	}
  
  	struct wlr_event_pointer_button event = {
  		.device = &pointer->input_device->wlr_input_device,
  		.button = button,
  		.state = state,
  		.time_msec = time,
  	};
  	wlr_signal_emit_safe(&pointer->wlr_pointer.events.button, &event);
  }
  
  static void pointer_handle_axis(void *data, struct wl_pointer *wl_pointer,
  		uint32_t time, uint32_t axis, wl_fixed_t value) {
  	struct wlr_wl_backend *backend = data;
  	struct wlr_wl_pointer *pointer = backend->current_pointer;
  	if (pointer == NULL) {
  		return;
  	}
  
  	struct wlr_event_pointer_axis event = {
  		.device = &pointer->input_device->wlr_input_device,
  		.delta = wl_fixed_to_double(value),
  		.delta_discrete = pointer->axis_discrete,
  		.orientation = axis,
  		.time_msec = time,
  		.source = pointer->axis_source,
  	};
  	wlr_signal_emit_safe(&pointer->wlr_pointer.events.axis, &event);
  
  	pointer->axis_discrete = 0;
  }
  
  static void pointer_handle_frame(void *data, struct wl_pointer *wl_pointer) {
  	struct wlr_wl_backend *backend = data;
  	struct wlr_wl_pointer *pointer = backend->current_pointer;
  	if (pointer == NULL) {
  		return;
  	}
  
  	wlr_signal_emit_safe(&pointer->wlr_pointer.events.frame,
  		&pointer->wlr_pointer);
  }
  
  static void pointer_handle_axis_source(void *data,
  		struct wl_pointer *wl_pointer, uint32_t axis_source) {
  	struct wlr_wl_backend *backend = data;
  	struct wlr_wl_pointer *pointer = backend->current_pointer;
  	if (pointer == NULL) {
  		return;
  	}
  
  	pointer->axis_source = axis_source;
  }
  
  static void pointer_handle_axis_stop(void *data, struct wl_pointer *wl_pointer,
  		uint32_t time, uint32_t axis) {
  	struct wlr_wl_backend *backend = data;
  	struct wlr_wl_pointer *pointer = backend->current_pointer;
  	if (pointer == NULL) {
  		return;
  	}
  
  	struct wlr_event_pointer_axis event = {
  		.device = &pointer->input_device->wlr_input_device,
  		.delta = 0,
  		.delta_discrete = 0,
  		.orientation = axis,
  		.time_msec = time,
  		.source = pointer->axis_source,
  	};
  	wlr_signal_emit_safe(&pointer->wlr_pointer.events.axis, &event);
  }
  
  static void pointer_handle_axis_discrete(void *data,
  		struct wl_pointer *wl_pointer, uint32_t axis, int32_t discrete) {
  	struct wlr_wl_backend *backend = data;
  	struct wlr_wl_pointer *pointer = backend->current_pointer;
  	if (pointer == NULL) {
  		return;
  	}
  
  	pointer->axis_discrete = discrete;
  }
  
  static const struct wl_pointer_listener pointer_listener = {
  	.enter = pointer_handle_enter,
  	.leave = pointer_handle_leave,
  	.motion = pointer_handle_motion,
  	.button = pointer_handle_button,
  	.axis = pointer_handle_axis,
  	.frame = pointer_handle_frame,
  	.axis_source = pointer_handle_axis_source,
  	.axis_stop = pointer_handle_axis_stop,
  	.axis_discrete = pointer_handle_axis_discrete,
  };
  
  static void keyboard_handle_keymap(void *data, struct wl_keyboard *wl_keyboard,
  		uint32_t format, int32_t fd, uint32_t size) {
  	close(fd);
  }
  
  static void keyboard_handle_enter(void *data, struct wl_keyboard *wl_keyboard,
  		uint32_t serial, struct wl_surface *surface, struct wl_array *keys) {
  	struct wlr_input_device *dev = data;
  
  	uint32_t time = get_current_time_msec();
  
  	uint32_t *keycode_ptr;
  	wl_array_for_each(keycode_ptr, keys) {
  		struct wlr_event_keyboard_key event = {
  			.keycode = *keycode_ptr,
  			.state = WLR_KEY_PRESSED,
  			.time_msec = time,
  			.update_state = false,
  		};
  		wlr_keyboard_notify_key(dev->keyboard, &event);
  	}
  }
  
  static void keyboard_handle_leave(void *data, struct wl_keyboard *wl_keyboard,
  		uint32_t serial, struct wl_surface *surface) {
  	struct wlr_input_device *dev = data;
  
  	uint32_t time = get_current_time_msec();
  
  	uint32_t pressed[dev->keyboard->num_keycodes + 1];
  	memcpy(pressed, dev->keyboard->keycodes,
  		dev->keyboard->num_keycodes * sizeof(uint32_t));
  
  	for (size_t i = 0; i < sizeof(pressed)/sizeof(pressed[0]); ++i) {
  		uint32_t keycode = pressed[i];
  
  		struct wlr_event_keyboard_key event = {
  			.keycode = keycode,
  			.state = WLR_KEY_RELEASED,
  			.time_msec = time,
  			.update_state = false,
  		};
  		wlr_keyboard_notify_key(dev->keyboard, &event);
  	}
  }
  
  static void keyboard_handle_key(void *data, struct wl_keyboard *wl_keyboard,
  		uint32_t serial, uint32_t time, uint32_t key, uint32_t state) {
  	struct wlr_input_device *dev = data;
  	assert(dev && dev->keyboard);
  
  	struct wlr_event_keyboard_key wlr_event = {
  		.keycode = key,
  		.state = state,
  		.time_msec = time,
  		.update_state = false,
  	};
  	wlr_keyboard_notify_key(dev->keyboard, &wlr_event);
  }
  
  static void keyboard_handle_modifiers(void *data, struct wl_keyboard *wl_keyboard,
  		uint32_t serial, uint32_t mods_depressed, uint32_t mods_latched,
  		uint32_t mods_locked, uint32_t group) {
  	struct wlr_input_device *dev = data;
  	assert(dev && dev->keyboard);
  	wlr_keyboard_notify_modifiers(dev->keyboard, mods_depressed, mods_latched,
  		mods_locked, group);
  }
  
  static void keyboard_handle_repeat_info(void *data,
  		struct wl_keyboard *wl_keyboard, int32_t rate, int32_t delay) {
  	// This space is intentionally left blank
  }
  
  static struct wl_keyboard_listener keyboard_listener = {
  	.keymap = keyboard_handle_keymap,
  	.enter = keyboard_handle_enter,
  	.leave = keyboard_handle_leave,
  	.key = keyboard_handle_key,
  	.modifiers = keyboard_handle_modifiers,
  	.repeat_info = keyboard_handle_repeat_info
  };
  
  static struct wlr_wl_input_device *get_wl_input_device_from_input_device(
  		struct wlr_input_device *wlr_dev) {
  	assert(wlr_input_device_is_wl(wlr_dev));
  	return (struct wlr_wl_input_device *)wlr_dev;
  }
  
  static void input_device_destroy(struct wlr_input_device *wlr_dev) {
  	struct wlr_wl_input_device *dev =
  		get_wl_input_device_from_input_device(wlr_dev);
  	if (dev->wlr_input_device.type == WLR_INPUT_DEVICE_KEYBOARD) {
  		wl_keyboard_release(dev->backend->keyboard);
  		dev->backend->keyboard = NULL;
  	}
  	wl_list_remove(&dev->wlr_input_device.link);
  	free(dev);
  }
  
  static struct wlr_input_device_impl input_device_impl = {
  	.destroy = input_device_destroy,
  };
  
  bool wlr_input_device_is_wl(struct wlr_input_device *dev) {
  	return dev->impl == &input_device_impl;
  }
  
  struct wlr_wl_input_device *create_wl_input_device(
  		struct wlr_wl_backend *backend, enum wlr_input_device_type type) {
  	struct wlr_wl_input_device *dev =
  		calloc(1, sizeof(struct wlr_wl_input_device));
  	if (dev == NULL) {
  		wlr_log_errno(WLR_ERROR, "Allocation failed");
  		return NULL;
  	}
  	dev->backend = backend;
  
  	struct wlr_input_device *wlr_dev = &dev->wlr_input_device;
  
  	unsigned int vendor = 0, product = 0;
  	const char *name = "wayland";
  	wlr_input_device_init(wlr_dev, type, &input_device_impl, name, vendor,
  		product);
  	wl_list_insert(&backend->devices, &wlr_dev->link);
  	return dev;
  }
  
  static struct wlr_pointer_impl pointer_impl;
  
  struct wlr_wl_pointer *pointer_get_wl(struct wlr_pointer *wlr_pointer) {
  	assert(wlr_pointer->impl == &pointer_impl);
  	return (struct wlr_wl_pointer *)wlr_pointer;
  }
  
  static void pointer_destroy(struct wlr_pointer *wlr_pointer) {
  	struct wlr_wl_pointer *pointer = pointer_get_wl(wlr_pointer);
  
  	if (pointer->output->backend->current_pointer == pointer) {
  		pointer->output->backend->current_pointer = NULL;
  	}
  
  	wl_list_remove(&pointer->output_destroy.link);
  	free(pointer);
  }
  
  static struct wlr_pointer_impl pointer_impl = {
  	.destroy = pointer_destroy,
  };
  
  static void gesture_swipe_begin(void *data,
  		struct zwp_pointer_gesture_swipe_v1 *zwp_pointer_gesture_swipe_v1,
  		uint32_t serial, uint32_t time,
  		struct wl_surface *surface, uint32_t fingers) {
  	struct wlr_wl_input_device *input_device = (struct wlr_wl_input_device *)data;
  	struct wlr_input_device *wlr_dev = &input_device->wlr_input_device;
  	struct wlr_event_pointer_swipe_begin wlr_event = {
  		.device = wlr_dev,
  		.time_msec = time,
  		.fingers = fingers,
  	};
  	input_device->fingers = fingers;
  	wlr_signal_emit_safe(&wlr_dev->pointer->events.swipe_begin, &wlr_event);
  }
  
  static void gesture_swipe_update(void *data,
  		struct zwp_pointer_gesture_swipe_v1 *zwp_pointer_gesture_swipe_v1,
  		uint32_t time, wl_fixed_t dx, wl_fixed_t dy) {
  	struct wlr_wl_input_device *input_device = (struct wlr_wl_input_device *)data;
  	struct wlr_input_device *wlr_dev = &input_device->wlr_input_device;
  	struct wlr_event_pointer_swipe_update wlr_event = {
  		.device = wlr_dev,
  		.time_msec = time,
  		.fingers = input_device->fingers,
  		.dx = wl_fixed_to_double(dx),
  		.dy = wl_fixed_to_double(dy),
  	};
  	wlr_signal_emit_safe(&wlr_dev->pointer->events.swipe_update, &wlr_event);
  }
  
  static void gesture_swipe_end(void *data,
  		struct zwp_pointer_gesture_swipe_v1 *zwp_pointer_gesture_swipe_v1,
  		uint32_t serial, uint32_t time, int32_t cancelled) {
  	struct wlr_wl_input_device *input_device = (struct wlr_wl_input_device *)data;
  	struct wlr_input_device *wlr_dev = &input_device->wlr_input_device;
  	struct wlr_event_pointer_swipe_end wlr_event = {
  		.device = wlr_dev,
  		.time_msec = time,
  		.cancelled = cancelled,
  	};
  	wlr_signal_emit_safe(&wlr_dev->pointer->events.swipe_end, &wlr_event);
  }
  
  static struct zwp_pointer_gesture_swipe_v1_listener gesture_swipe_impl = {
  	.begin = gesture_swipe_begin,
  	.update = gesture_swipe_update,
  	.end = gesture_swipe_end,
  };
  
  static void gesture_pinch_begin(void *data,
  		struct zwp_pointer_gesture_pinch_v1 *zwp_pointer_gesture_pinch_v1,
  		uint32_t serial, uint32_t time,
  		struct wl_surface *surface, uint32_t fingers) {
  	struct wlr_wl_input_device *input_device = (struct wlr_wl_input_device *)data;
  	struct wlr_input_device *wlr_dev = &input_device->wlr_input_device;
  	struct wlr_event_pointer_pinch_begin wlr_event = {
  		.device = wlr_dev,
  		.time_msec = time,
  		.fingers = fingers,
  	};
  	input_device->fingers = fingers;
  	wlr_signal_emit_safe(&wlr_dev->pointer->events.pinch_begin, &wlr_event);
  }
  
  static void gesture_pinch_update(void *data,
  		struct zwp_pointer_gesture_pinch_v1 *zwp_pointer_gesture_pinch_v1,
  		uint32_t time, wl_fixed_t dx, wl_fixed_t dy, wl_fixed_t scale, wl_fixed_t rotation) {
  	struct wlr_wl_input_device *input_device = (struct wlr_wl_input_device *)data;
  	struct wlr_input_device *wlr_dev = &input_device->wlr_input_device;
  	struct wlr_event_pointer_pinch_update wlr_event = {
  		.device = wlr_dev,
  		.time_msec = time,
  		.fingers = input_device->fingers,
  		.dx = wl_fixed_to_double(dx),
  		.dy = wl_fixed_to_double(dy),
  		.scale = wl_fixed_to_double(scale),
  		.rotation = wl_fixed_to_double(rotation),
  	};
  	wlr_signal_emit_safe(&wlr_dev->pointer->events.pinch_update, &wlr_event);
  }
  
  static void gesture_pinch_end(void *data,
  		struct zwp_pointer_gesture_pinch_v1 *zwp_pointer_gesture_pinch_v1,
  		uint32_t serial, uint32_t time, int32_t cancelled) {
  	struct wlr_wl_input_device *input_device = (struct wlr_wl_input_device *)data;
  	struct wlr_input_device *wlr_dev = &input_device->wlr_input_device;
  	struct wlr_event_pointer_pinch_end wlr_event = {
  		.device = wlr_dev,
  		.time_msec = time,
  		.cancelled = cancelled,
  	};
  	wlr_signal_emit_safe(&wlr_dev->pointer->events.pinch_end, &wlr_event);
  }
  
  static struct zwp_pointer_gesture_pinch_v1_listener gesture_pinch_impl = {
  	.begin = gesture_pinch_begin,
  	.update = gesture_pinch_update,
  	.end = gesture_pinch_end,
  };
  
  
  static void relative_pointer_handle_relative_motion(void *data,
  		struct zwp_relative_pointer_v1 *relative_pointer, uint32_t utime_hi,
  		uint32_t utime_lo, wl_fixed_t dx, wl_fixed_t dy, wl_fixed_t dx_unaccel,
  		wl_fixed_t dy_unaccel) {
  	struct wlr_wl_input_device *input_device = data;
  	struct wlr_input_device *wlr_dev = &input_device->wlr_input_device;
  
  	uint64_t time_usec = (uint64_t)utime_hi << 32 | utime_lo;
  
  	struct wlr_event_pointer_motion wlr_event = {
  		.device = wlr_dev,
  		.time_msec = (uint32_t)(time_usec / 1000),
  		.delta_x = wl_fixed_to_double(dx),
  		.delta_y = wl_fixed_to_double(dy),
  		.unaccel_dx = wl_fixed_to_double(dx_unaccel),
  		.unaccel_dy = wl_fixed_to_double(dy_unaccel),
  	};
  	wlr_signal_emit_safe(&wlr_dev->pointer->events.motion, &wlr_event);
  }
  
  static const struct zwp_relative_pointer_v1_listener relative_pointer_listener = {
  	.relative_motion = relative_pointer_handle_relative_motion,
  };
  
  
  static void pointer_handle_output_destroy(struct wl_listener *listener,
  		void *data) {
  	struct wlr_wl_pointer *pointer =
  		wl_container_of(listener, pointer, output_destroy);
  	if (pointer->relative_pointer) {
  		zwp_relative_pointer_v1_destroy(pointer->relative_pointer);
  	}
  	wlr_input_device_destroy(&pointer->input_device->wlr_input_device);
  }
  
  void create_wl_pointer(struct wl_pointer *wl_pointer, struct wlr_wl_output *output) {
  	struct wlr_wl_backend *backend = output->backend;
  
  	struct wlr_input_device *wlr_dev;
  	wl_list_for_each(wlr_dev, &output->backend->devices, link) {
  		if (wlr_dev->type != WLR_INPUT_DEVICE_POINTER) {
  			continue;
  		}
  		struct wlr_wl_pointer *pointer = pointer_get_wl(wlr_dev->pointer);
  		if (pointer->output == output) {
  			return;
  		}
  	}
  
  	struct wlr_wl_pointer *pointer = calloc(1, sizeof(struct wlr_wl_pointer));
  	if (pointer == NULL) {
  		wlr_log(WLR_ERROR, "Allocation failed");
  		return;
  	}
  	pointer->wl_pointer = wl_pointer;
  	pointer->output = output;
  
  	wl_signal_add(&output->wlr_output.events.destroy, &pointer->output_destroy);
  	pointer->output_destroy.notify = pointer_handle_output_destroy;
  
  	struct wlr_wl_input_device *dev =
  		create_wl_input_device(backend, WLR_INPUT_DEVICE_POINTER);
  	if (dev == NULL) {
  		free(pointer);
  		wlr_log(WLR_ERROR, "Allocation failed");
  		return;
  	}
  	pointer->input_device = dev;
  
  	wlr_dev = &dev->wlr_input_device;
  	wlr_dev->pointer = &pointer->wlr_pointer;
  	wlr_dev->output_name = strdup(output->wlr_output.name);
  	wlr_pointer_init(wlr_dev->pointer, &pointer_impl);
  
  	if (backend->zwp_pointer_gestures_v1) {
  		pointer->gesture_swipe = zwp_pointer_gestures_v1_get_swipe_gesture(
  				backend->zwp_pointer_gestures_v1, wl_pointer);
  		zwp_pointer_gesture_swipe_v1_add_listener(pointer->gesture_swipe, &gesture_swipe_impl, dev);
  		pointer->gesture_pinch = zwp_pointer_gestures_v1_get_pinch_gesture(
  				backend->zwp_pointer_gestures_v1, wl_pointer);
  		zwp_pointer_gesture_pinch_v1_add_listener(pointer->gesture_pinch, &gesture_pinch_impl, dev);
  	}
  
  	if (backend->zwp_relative_pointer_manager_v1) {
  		pointer->relative_pointer =
  			zwp_relative_pointer_manager_v1_get_relative_pointer(
  			backend->zwp_relative_pointer_manager_v1, wl_pointer);
  		zwp_relative_pointer_v1_add_listener(pointer->relative_pointer,
  			&relative_pointer_listener, dev);
  	}
  
  	wl_pointer_add_listener(wl_pointer, &pointer_listener, backend);
  	wlr_signal_emit_safe(&backend->backend.events.new_input, wlr_dev);
  }
  
  void create_wl_keyboard(struct wl_keyboard *wl_keyboard, struct wlr_wl_backend *wl) {
  	struct wlr_wl_input_device *dev =
  		create_wl_input_device(wl, WLR_INPUT_DEVICE_KEYBOARD);
  	if (!dev) {
  		return;
  	}
  
  	struct wlr_input_device *wlr_dev = &dev->wlr_input_device;
  
  	wlr_dev->keyboard = calloc(1, sizeof(*wlr_dev->keyboard));
  	if (!wlr_dev->keyboard) {
  		wlr_log_errno(WLR_ERROR, "Allocation failed");
  		free(dev);
  		return;
  	}
  	wlr_keyboard_init(wlr_dev->keyboard, NULL);
  
  	wl_keyboard_add_listener(wl_keyboard, &keyboard_listener, wlr_dev);
  	wlr_signal_emit_safe(&wl->backend.events.new_input, wlr_dev);
  }
  
  static void seat_handle_capabilities(void *data, struct wl_seat *wl_seat,
  		enum wl_seat_capability caps) {
  	struct wlr_wl_backend *backend = data;
  	assert(backend->seat == wl_seat);
  
  	if ((caps & WL_SEAT_CAPABILITY_POINTER) && backend->pointer == NULL) {
  		wlr_log(WLR_DEBUG, "seat %p offered pointer", (void *)wl_seat);
  
  		struct wl_pointer *wl_pointer = wl_seat_get_pointer(wl_seat);
  		backend->pointer = wl_pointer;
  
  		struct wlr_wl_output *output;
  		wl_list_for_each(output, &backend->outputs, link) {
  			create_wl_pointer(wl_pointer, output);
  		}
  	}
  	if (!(caps & WL_SEAT_CAPABILITY_POINTER) && backend->pointer != NULL) {
  		wlr_log(WLR_DEBUG, "seat %p dropped pointer", (void *)wl_seat);
  
  		struct wlr_input_device *device, *tmp;
  		wl_list_for_each_safe(device, tmp, &backend->devices, link) {
  			if (device->type == WLR_INPUT_DEVICE_POINTER) {
  				wlr_input_device_destroy(device);
  			}
  		}
  
  		wl_pointer_release(backend->pointer);
  		backend->pointer = NULL;
  	}
  
  	if ((caps & WL_SEAT_CAPABILITY_KEYBOARD) && backend->keyboard == NULL) {
  		wlr_log(WLR_DEBUG, "seat %p offered keyboard", (void *)wl_seat);
  
  		struct wl_keyboard *wl_keyboard = wl_seat_get_keyboard(wl_seat);
  		backend->keyboard = wl_keyboard;
  
  		if (backend->started) {
  			create_wl_keyboard(wl_keyboard, backend);
  		}
  	}
  	if (!(caps & WL_SEAT_CAPABILITY_KEYBOARD) && backend->keyboard != NULL) {
  		wlr_log(WLR_DEBUG, "seat %p dropped keyboard", (void *)wl_seat);
  
  		struct wlr_input_device *device, *tmp;
  		wl_list_for_each_safe(device, tmp, &backend->devices, link) {
  			if (device->type == WLR_INPUT_DEVICE_KEYBOARD) {
  				wlr_input_device_destroy(device);
  			}
  		}
  		assert(backend->keyboard == NULL); // free'ed by input_device_destroy
  	}
  }
  
  static void seat_handle_name(void *data, struct wl_seat *wl_seat,
  		const char *name) {
  	struct wlr_wl_backend *backend = data;
  	assert(backend->seat == wl_seat);
  	// Do we need to check if seatName was previously set for name change?
  	free(backend->seat_name);
  	backend->seat_name = strdup(name);
  }
  
  const struct wl_seat_listener seat_listener = {
  	.capabilities = seat_handle_capabilities,
  	.name = seat_handle_name,
  };
  
  struct wl_seat *wlr_wl_input_device_get_seat(struct wlr_input_device *wlr_dev) {
  	struct wlr_wl_input_device *dev =
  		get_wl_input_device_from_input_device(wlr_dev);
  	return dev->backend->seat;
  }
  