Switch protocol to using serial numbers for ordering events and requests

The wayland protocol, as X, uses timestamps to match up certain
requests with input events.  The problem is that sometimes we need to
send out an event that doesn't have a corresponding timestamped input
event.  For example, the pointer focus surface goes away and new
surface needs to receive a pointer enter event.  These events are
normally timestamped with the evdev event timestamp, but in this case,
we don't have a evdev timestamp.  So we have to go to gettimeofday (or
clock_gettime()) and then we don't know if it's coming from the same
time source etc.

However for all these cases we don't need a real time timestamp, we
just need a serial number that encodes the order of events inside the
server.  So we introduce a serial number mechanism that we can use to
order events.  We still need real-time timestamps for actual input
device events (motion, buttons, keys, touch), to be able to reason
about double-click speed and movement speed so events that correspond to user input carry both a serial number and a timestamp.

The serial number also give us a mechanism to key together events that
are "logically the same" such as a unicode event and a keycode event,
or a motion event and a relative event from a raw device.

5 files changed, 112 insertions, 78 deletions

diff --git a/src/data-device.c b/src/data-device.c
index 03997f1..1d22a84 100644
--- a/src/data-device.c
+++ b/src/data-device.c
@@ -29,7 +29,7 @@
 
 static void
 data_offer_accept(struct wl_client *client, struct wl_resource *resource,
-		  uint32_t time, const char *mime_type)
+		  uint32_t serial, const char *mime_type)
 {
 	struct wl_data_offer *offer = resource->data;
 
@@ -58,7 +58,7 @@ data_offer_receive(struct wl_client *client, struct wl_resource *resource,
 static void
 data_offer_destroy(struct wl_client *client, struct wl_resource *resource)
 {
-	wl_resource_destroy(resource, 0);
+	wl_resource_destroy(resource);
 }
 
 static void
@@ -78,7 +78,7 @@ static const struct wl_data_offer_interface data_offer_interface = {
 
 static void
 destroy_offer_data_source(struct wl_listener *listener,
-			  struct wl_resource *resource, uint32_t time)
+			  struct wl_resource *resource)
 {
 	struct wl_data_offer *offer;
 
@@ -146,7 +146,7 @@ data_source_offer(struct wl_client *client,
 static void
 data_source_destroy(struct wl_client *client, struct wl_resource *resource)
 {
-	wl_resource_destroy(resource, 0);
+	wl_resource_destroy(resource);
 }
 
 static struct wl_data_source_interface data_source_interface = {
@@ -169,7 +169,7 @@ find_resource(struct wl_list *list, struct wl_client *client)
 
 static void
 destroy_drag_focus(struct wl_listener *listener,
-		   struct wl_resource *resource, uint32_t time)
+		   struct wl_resource *resource)
 {
 	struct wl_input_device *device =
 		container_of(listener, struct wl_input_device,
@@ -179,12 +179,14 @@ destroy_drag_focus(struct wl_listener *listener,
 }
 
 static void
-drag_grab_focus(struct wl_pointer_grab *grab, uint32_t time,
+drag_grab_focus(struct wl_pointer_grab *grab,
 		struct wl_surface *surface, int32_t x, int32_t y)
 {
 	struct wl_input_device *device =
 		container_of(grab, struct wl_input_device, drag_grab);
 	struct wl_resource *resource, *offer;
+	struct wl_display *display;
+	uint32_t serial;
 
 	if (device->drag_focus_resource) {
 		wl_data_device_send_leave(device->drag_focus_resource);
@@ -197,10 +199,13 @@ drag_grab_focus(struct wl_pointer_grab *grab, uint32_t time,
 		resource = find_resource(&device->drag_resource_list, 
 					 surface->resource.client);
 	if (surface && resource) {
+		display = wl_client_get_display(resource->client);
+		serial = wl_display_next_serial(display);
+
 		offer = wl_data_source_send_offer(device->drag_data_source,
 						  resource);
 
-		wl_data_device_send_enter(resource, time, &surface->resource,
+		wl_data_device_send_enter(resource, serial, &surface->resource,
 					  x, y, offer);
 
 		device->drag_focus = surface;
@@ -225,7 +230,7 @@ drag_grab_motion(struct wl_pointer_grab *grab,
 }
 
 static void
-data_device_end_drag_grab(struct wl_input_device *device, uint32_t time)
+data_device_end_drag_grab(struct wl_input_device *device)
 {
 	struct wl_resource *surface_resource;
 	struct wl_surface_interface *implementation;
@@ -240,7 +245,7 @@ data_device_end_drag_grab(struct wl_input_device *device, uint32_t time)
 		wl_list_remove(&device->drag_icon_listener.link);
 	}
 
-	wl_input_device_end_pointer_grab(device, time);
+	wl_input_device_end_pointer_grab(device);
 
 	device->drag_data_source = NULL;
 	device->drag_surface = NULL;
@@ -258,7 +263,7 @@ drag_grab_button(struct wl_pointer_grab *grab,
 		wl_data_device_send_drop(device->drag_focus_resource);
 
 	if (device->button_count == 0 && state == 0) {
-		data_device_end_drag_grab(device, time);
+		data_device_end_drag_grab(device);
 		wl_list_remove(&device->drag_data_source_listener.link);
 	}
 }
@@ -271,19 +276,19 @@ static const struct wl_pointer_grab_interface drag_grab_interface = {
 
 static void
 destroy_data_device_source(struct wl_listener *listener,
-			   struct wl_resource *resource, uint32_t time)
+			   struct wl_resource *resource)
 {
 	struct wl_input_device *device;
 
 	device = container_of(listener, struct wl_input_device,
 			      drag_data_source_listener);
 
-	data_device_end_drag_grab(device, time);
+	data_device_end_drag_grab(device);
 }
 
 static void
 destroy_data_device_icon(struct wl_listener *listener,
-			 struct wl_resource *resource, uint32_t time)
+			 struct wl_resource *resource)
 {
 	struct wl_input_device *device;
 
@@ -297,7 +302,7 @@ static void
 data_device_start_drag(struct wl_client *client, struct wl_resource *resource,
 		       struct wl_resource *source_resource,
 		       struct wl_resource *origin_resource,
-		       struct wl_resource *icon_resource, uint32_t time)
+		       struct wl_resource *icon_resource, uint32_t serial)
 {
 	struct wl_input_device *device = resource->data;
 	struct wl_listener *listener, *tmp;
@@ -322,15 +327,15 @@ data_device_start_drag(struct wl_client *client, struct wl_resource *resource,
 
 		wl_list_for_each_safe(listener, tmp,
 				      &device->drag_icon_listener_list, link)
-			listener->func(listener, icon_resource, time);
+			listener->func(listener, icon_resource);
 	}
 
-	wl_input_device_start_pointer_grab(device, &device->drag_grab, time);
+	wl_input_device_start_pointer_grab(device, &device->drag_grab);
 }
 
 static void
 destroy_selection_data_source(struct wl_listener *listener,
-			      struct wl_resource *resource, uint32_t time)
+			      struct wl_resource *resource)
 {
 	struct wl_input_device *device =
 		container_of(listener, struct wl_input_device,
@@ -349,7 +354,7 @@ destroy_selection_data_source(struct wl_listener *listener,
 
 WL_EXPORT void
 wl_input_device_set_selection(struct wl_input_device *device,
-			      struct wl_data_source *source, uint32_t time)
+			      struct wl_data_source *source)
 {
 	struct wl_resource *data_device, *focus, *offer;
 	struct wl_selection_listener *listener, *next;
@@ -386,13 +391,13 @@ wl_input_device_set_selection(struct wl_input_device *device,
 static void
 data_device_set_selection(struct wl_client *client,
 			  struct wl_resource *resource,
-			  struct wl_resource *source_resource, uint32_t time)
+			  struct wl_resource *source_resource, uint32_t serial)
 {
 	if (!source_resource)
 		return;
 
-	wl_input_device_set_selection(resource->data,
-				      source_resource->data, time);
+	/* FIXME: Store serial and check against incoming serial here. */
+	wl_input_device_set_selection(resource->data, source_resource->data);
 }
 
 static const struct wl_data_device_interface data_device_interface = {
diff --git a/src/wayland-client.c b/src/wayland-client.c
index 9057b4f..713c894 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -433,7 +433,7 @@ wl_display_get_fd(struct wl_display *display,
 }
 
 static void
-sync_callback(void *data, struct wl_callback *callback, uint32_t time)
+sync_callback(void *data, struct wl_callback *callback, uint32_t serial)
 {
    int *done = data;
 
diff --git a/src/wayland-server.c b/src/wayland-server.c
index a649d66..e6eccd6 100644
--- a/src/wayland-server.c
+++ b/src/wayland-server.c
@@ -72,6 +72,7 @@ struct wl_display {
 	int run;
 
 	uint32_t id;
+	uint32_t serial;
 
 	struct wl_list global_list;
 	struct wl_list socket_list;
@@ -382,23 +383,22 @@ destroy_resource(void *element, void *data)
 {
 	struct wl_resource *resource = element;
  	struct wl_listener *l, *next;
-	uint32_t *time = data;
 
 	wl_list_for_each_safe(l, next, &resource->destroy_listener_list, link)
-		l->func(l, resource, *time);
+		l->func(l, resource);
 
 	if (resource->destroy)
 		resource->destroy(resource);
 }
 
 WL_EXPORT void
-wl_resource_destroy(struct wl_resource *resource, uint32_t time)
+wl_resource_destroy(struct wl_resource *resource)
 {
 	struct wl_client *client = resource->client;
 	uint32_t id;
 
 	id = resource->object.id;
-	destroy_resource(resource, &time);
+	destroy_resource(resource, NULL);
 
 	if (id < WL_SERVER_ID_START) {
 		if (client->display_resource) {
@@ -414,12 +414,12 @@ wl_resource_destroy(struct wl_resource *resource, uint32_t time)
 WL_EXPORT void
 wl_client_destroy(struct wl_client *client)
 {
-	uint32_t time = 0;
+	uint32_t serial = 0;
 	
 	printf("disconnect from client %p\n", client);
 
 	wl_client_flush(client);
-	wl_map_for_each(&client->objects, destroy_resource, &time);
+	wl_map_for_each(&client->objects, destroy_resource, &serial);
 	wl_map_release(&client->objects);
 	wl_event_source_remove(client->source);
 	wl_connection_destroy(client->connection);
@@ -429,7 +429,7 @@ wl_client_destroy(struct wl_client *client)
 
 static void
 lose_pointer_focus(struct wl_listener *listener,
-		   struct wl_resource *resource, uint32_t time)
+		   struct wl_resource *resource)
 {
 	struct wl_input_device *device =
 		container_of(listener, struct wl_input_device,
@@ -440,7 +440,7 @@ lose_pointer_focus(struct wl_listener *listener,
 
 static void
 lose_keyboard_focus(struct wl_listener *listener,
-		    struct wl_resource *resource, uint32_t time)
+		    struct wl_resource *resource)
 {
 	struct wl_input_device *device =
 		container_of(listener, struct wl_input_device,
@@ -450,7 +450,7 @@ lose_keyboard_focus(struct wl_listener *listener,
 }
 
 static void
-default_grab_focus(struct wl_pointer_grab *grab, uint32_t time,
+default_grab_focus(struct wl_pointer_grab *grab,
 		   struct wl_surface *surface, int32_t x, int32_t y)
 {
 	struct wl_input_device *device = grab->input_device;
@@ -458,7 +458,7 @@ default_grab_focus(struct wl_pointer_grab *grab, uint32_t time,
 	if (device->button_count > 0)
 		return;
 
-	wl_input_device_set_pointer_focus(device, surface, time, x, y);
+	wl_input_device_set_pointer_focus(device, surface, x, y);
 }
 
 static void
@@ -478,14 +478,18 @@ default_grab_button(struct wl_pointer_grab *grab,
 {
 	struct wl_input_device *device = grab->input_device;
 	struct wl_resource *resource;
+	uint32_t serial;
 
 	resource = device->pointer_focus_resource;
-	if (resource)
-		wl_input_device_send_button(resource, time, button, state);
+	if (resource) {
+		serial = wl_display_next_serial(resource->client->display);
+		wl_input_device_send_button(resource, serial, time,
+					    button, state);
+	}
 
 	if (device->button_count == 0 && state == 0)
 		wl_input_device_set_pointer_focus(device,
-						  device->current, time,
+						  device->current,
 						  device->current_x,
 						  device->current_y);
 }
@@ -499,14 +503,17 @@ static const struct wl_pointer_grab_interface
 
 static void
 default_grab_key(struct wl_keyboard_grab *grab,
-		    uint32_t time, uint32_t key, int32_t state)
+		 uint32_t time, uint32_t key, int32_t state)
 {
 	struct wl_input_device *device = grab->input_device;
 	struct wl_resource *resource;
+	uint32_t serial;
 
 	resource = device->keyboard_focus_resource;
-	if (resource)
-		wl_input_device_send_key(resource, time, key, state);
+	if (resource) {
+		serial = wl_display_next_serial(resource->client->display);
+		wl_input_device_send_key(resource, serial, time, key, state);
+	}
 }
 
 static const struct wl_keyboard_grab_interface
@@ -574,70 +581,75 @@ find_resource_for_surface(struct wl_list *list, struct wl_surface *surface)
 WL_EXPORT void
 wl_input_device_set_pointer_focus(struct wl_input_device *device,
 				  struct wl_surface *surface,
-				  uint32_t time,
 				  int32_t sx, int32_t sy)
 {
 	struct wl_resource *resource;
+	uint32_t serial;
 
 	if (device->pointer_focus == surface)
 		return;
 
-	if (device->pointer_focus_resource) {
-		wl_input_device_send_pointer_leave(
-			device->pointer_focus_resource,
-			time, &device->pointer_focus->resource);
+	resource = device->pointer_focus_resource;
+	if (resource) {
+		serial = wl_display_next_serial(resource->client->display);
+		wl_input_device_send_pointer_leave(resource, serial,
+			&device->pointer_focus->resource);
 		wl_list_remove(&device->pointer_focus_listener.link);
 	}
 
+
 	resource = find_resource_for_surface(&device->resource_list, surface);
 	if (resource) {
-		wl_input_device_send_pointer_enter(resource, time,
+		serial = wl_display_next_serial(resource->client->display);
+		wl_input_device_send_pointer_enter(resource, serial,
 						   &surface->resource,
 						   sx, sy);
 		wl_list_insert(resource->destroy_listener_list.prev,
 			       &device->pointer_focus_listener.link);
+		device->pointer_focus_serial = serial;
 	}
 
 	device->pointer_focus_resource = resource;
 	device->pointer_focus = surface;
-	device->pointer_focus_time = time;
 	device->default_pointer_grab.focus = surface;
 }
 
 WL_EXPORT void
 wl_input_device_set_keyboard_focus(struct wl_input_device *device,
-				   struct wl_surface *surface,
-				   uint32_t time)
+				   struct wl_surface *surface)
 {
 	struct wl_resource *resource;
+	uint32_t serial;
 
 	if (device->keyboard_focus == surface)
 		return;
 
 	if (device->keyboard_focus_resource) {
-		wl_input_device_send_keyboard_leave(
-			device->keyboard_focus_resource,
-			time, &device->keyboard_focus->resource);
+		resource = device->keyboard_focus_resource;
+		serial = wl_display_next_serial(resource->client->display);
+		wl_input_device_send_keyboard_leave(resource, serial,
+						    &device->keyboard_focus->resource);
 		wl_list_remove(&device->keyboard_focus_listener.link);
 	}
 
 	resource = find_resource_for_surface(&device->resource_list, surface);
 	if (resource) {
-		wl_input_device_send_keyboard_enter(resource, time,
+		serial = wl_display_next_serial(resource->client->display);
+		wl_input_device_send_keyboard_enter(resource, serial,
 						    &surface->resource,
 						    &device->keys);
 		wl_list_insert(resource->destroy_listener_list.prev,
 			       &device->keyboard_focus_listener.link);
+		device->keyboard_focus_serial = serial;
 	}
 
 	device->keyboard_focus_resource = resource;
 	device->keyboard_focus = surface;
-	device->keyboard_focus_time = time;
 }
 
 WL_EXPORT void
 wl_input_device_start_keyboard_grab(struct wl_input_device *device,
-			   struct wl_keyboard_grab *grab, uint32_t time)
+				    struct wl_keyboard_grab *grab)
 {
 	device->keyboard_grab = grab;
 	grab->input_device = device;
@@ -645,14 +657,14 @@ wl_input_device_start_keyboard_grab(struct wl_input_device *device,
 }
 
 WL_EXPORT void
-wl_input_device_end_keyboard_grab(struct wl_input_device *device, uint32_t time)
+wl_input_device_end_keyboard_grab(struct wl_input_device *device)
 {
 	device->keyboard_grab = &device->default_keyboard_grab;
 }
 
 WL_EXPORT void
 wl_input_device_start_pointer_grab(struct wl_input_device *device,
-			   struct wl_pointer_grab *grab, uint32_t time)
+				   struct wl_pointer_grab *grab)
 {
 	const struct wl_pointer_grab_interface *interface;
 
@@ -661,18 +673,18 @@ wl_input_device_start_pointer_grab(struct wl_input_device *device,
 	grab->input_device = device;
 
 	if (device->current)
-		interface->focus(device->pointer_grab, time, device->current,
+		interface->focus(device->pointer_grab, device->current,
 				 device->current_x, device->current_y);
 }
 
 WL_EXPORT void
-wl_input_device_end_pointer_grab(struct wl_input_device *device, uint32_t time)
+wl_input_device_end_pointer_grab(struct wl_input_device *device)
 {
 	const struct wl_pointer_grab_interface *interface;
 
 	device->pointer_grab = &device->default_pointer_grab;
 	interface = device->pointer_grab->interface;
-	interface->focus(device->pointer_grab, time, device->current,
+	interface->focus(device->pointer_grab, device->current,
 			 device->current_x, device->current_y);
 }
 
@@ -701,11 +713,13 @@ display_sync(struct wl_client *client,
 	     struct wl_resource *resource, uint32_t id)
 {
 	struct wl_resource *callback;
+	uint32_t serial;
 
 	callback = wl_client_add_object(client,
 					&wl_callback_interface, NULL, id, NULL);
-	wl_callback_send_done(callback, 0);
-	wl_resource_destroy(callback, 0);
+	serial = wl_display_get_serial(client->display);
+	wl_callback_send_done(callback, serial);
+	wl_resource_destroy(callback);
 }
 
 struct wl_display_interface display_interface = {
@@ -830,6 +844,20 @@ wl_display_remove_global(struct wl_display *display, struct wl_global *global)
 	free(global);
 }
 
+WL_EXPORT uint32_t
+wl_display_get_serial(struct wl_display *display)
+{
+	return display->serial;
+}
+
+WL_EXPORT uint32_t
+wl_display_next_serial(struct wl_display *display)
+{
+	display->serial++;
+
+	return display->serial;
+}
+
 WL_EXPORT struct wl_event_loop *
 wl_display_get_event_loop(struct wl_display *display)
 {
diff --git a/src/wayland-server.h b/src/wayland-server.h
index 6d2ab7c..4b34547 100644
--- a/src/wayland-server.h
+++ b/src/wayland-server.h
@@ -96,6 +96,9 @@ struct wl_global *wl_display_add_global(struct wl_display *display,
 void wl_display_remove_global(struct wl_display *display,
 			      struct wl_global *global);
 
+uint32_t wl_display_get_serial(struct wl_display *display);
+uint32_t wl_display_next_serial(struct wl_display *display);
+
 struct wl_client *wl_client_create(struct wl_display *display, int fd);
 void wl_client_destroy(struct wl_client *client);
 void wl_client_flush(struct wl_client *client);
@@ -129,7 +132,7 @@ struct wl_buffer {
 struct wl_listener {
 	struct wl_list link;
 	void (*func)(struct wl_listener *listener,
-		     struct wl_resource *resource, uint32_t time);
+		     struct wl_resource *resource);
 };
 
 struct wl_surface {
@@ -138,7 +141,7 @@ struct wl_surface {
 
 struct wl_pointer_grab;
 struct wl_pointer_grab_interface {
-	void (*focus)(struct wl_pointer_grab *grab, uint32_t time,
+	void (*focus)(struct wl_pointer_grab *grab,
 		      struct wl_surface *surface, int32_t x, int32_t y);
 	void (*motion)(struct wl_pointer_grab *grab,
 		       uint32_t time, int32_t x, int32_t y);
@@ -155,8 +158,8 @@ struct wl_pointer_grab {
 
 struct wl_keyboard_grab;
 struct wl_keyboard_grab_interface {
-	void (*key)(struct wl_keyboard_grab *grab,
-		       uint32_t time, uint32_t key, int32_t state);
+	void (*key)(struct wl_keyboard_grab *grab, uint32_t time,
+		    uint32_t key, int32_t state);
 };
 
 struct wl_keyboard_grab {
@@ -193,8 +196,8 @@ struct wl_input_device {
 	struct wl_resource *keyboard_focus_resource;
 	struct wl_surface *keyboard_focus;
 	struct wl_array keys;
-	uint32_t pointer_focus_time;
-	uint32_t keyboard_focus_time;
+	uint32_t pointer_focus_serial;
+	uint32_t keyboard_focus_serial;
 	struct wl_listener pointer_focus_listener;
 	struct wl_listener keyboard_focus_listener;
 
@@ -208,6 +211,7 @@ struct wl_input_device {
 	struct wl_keyboard_grab default_keyboard_grab;
 	uint32_t button_count;
 	uint32_t grab_time;
+	uint32_t grab_serial;
 	int32_t grab_x, grab_y;
 	uint32_t grab_button;
 	uint32_t grab_key;
@@ -266,7 +270,7 @@ struct wl_display *
 wl_client_get_display(struct wl_client *client);
 
 void
-wl_resource_destroy(struct wl_resource *resource, uint32_t time);
+wl_resource_destroy(struct wl_resource *resource);
 
 void
 wl_input_device_init(struct wl_input_device *device);
@@ -277,13 +281,11 @@ wl_input_device_release(struct wl_input_device *device);
 void
 wl_input_device_set_pointer_focus(struct wl_input_device *device,
 				  struct wl_surface *surface,
-				  uint32_t time,
 				  int32_t sx, int32_t sy);
 
 void
 wl_input_device_set_keyboard_focus(struct wl_input_device *device,
-				   struct wl_surface *surface,
-				   uint32_t time);
+				   struct wl_surface *surface);
 void
 wl_data_device_set_keyboard_focus(struct wl_input_device *device);
 int
@@ -291,20 +293,19 @@ wl_data_device_manager_init(struct wl_display *display);
 
 void
 wl_input_device_start_keyboard_grab(struct wl_input_device *device,
-			   struct wl_keyboard_grab *grab, uint32_t time);
+				    struct wl_keyboard_grab *grab);
 void
-wl_input_device_end_keyboard_grab(struct wl_input_device *device, uint32_t time);
+wl_input_device_end_keyboard_grab(struct wl_input_device *device);
 
 void
 wl_input_device_start_pointer_grab(struct wl_input_device *device,
-			   struct wl_pointer_grab *grab, uint32_t time);
+				   struct wl_pointer_grab *grab);
 void
-wl_input_device_end_pointer_grab(struct wl_input_device *device, uint32_t time);
+wl_input_device_end_pointer_grab(struct wl_input_device *device);
 
 void
 wl_input_device_set_selection(struct wl_input_device *device,
-			      struct wl_data_source *source,
-			      uint32_t time);
+			      struct wl_data_source *source);
 
 
 void *
diff --git a/src/wayland-shm.c b/src/wayland-shm.c
index 8f026d5..7900ba1 100644
--- a/src/wayland-shm.c
+++ b/src/wayland-shm.c
@@ -73,7 +73,7 @@ destroy_buffer(struct wl_resource *resource)
 static void
 shm_buffer_destroy(struct wl_client *client, struct wl_resource *resource)
 {
-	wl_resource_destroy(resource, 0);
+	wl_resource_destroy(resource);
 }
 
 static const struct wl_buffer_interface shm_buffer_interface = {
@@ -147,7 +147,7 @@ destroy_pool(struct wl_resource *resource)
 static void
 shm_pool_destroy(struct wl_client *client, struct wl_resource *resource)
 {
-	wl_resource_destroy(resource, 0);
+	wl_resource_destroy(resource);
 }
 
 struct wl_shm_pool_interface shm_pool_interface = {