[PATCH 3/3] client: Queue display events on private queue and always dispatch

[Kristian Høgsberg]

The wl_display events (error and delete_id) need to be handled even
if the default queue doesn't get dispatched for a while.  For example,
a busy EGL rendering loop hits wl_display.sync every eglSwapBuffers()
and we need to process the delete_id events to maintain the object ID
data structure.

As it is, that doesn't happen, but with this change we special case
wl_display events.  We put them on a custom, private queue and when
dispatching events, we always dispatch display_queue events first.
The wl_display proxy should still be the default_queue, so that objects
created from wl_display requests get assigned to that.
---
 src/wayland-client.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/src/wayland-client.c b/src/wayland-client.c
index 04b5115..208bc9c 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -83,6 +83,7 @@ struct wl_display {
 	int fd;
 	pthread_t display_thread;
 	struct wl_map objects;
+	struct wl_event_queue display_queue;
 	struct wl_event_queue default_queue;
 	struct wl_list event_queue_list;
 	pthread_mutex_t mutex;
@@ -713,6 +714,7 @@ wl_display_connect_to_fd(int fd)
 	display->fd = fd;
 	wl_map_init(&display->objects, WL_MAP_CLIENT_SIDE);
 	wl_event_queue_init(&display->default_queue, display);
+	wl_event_queue_init(&display->display_queue, display);
 	wl_list_init(&display->event_queue_list);
 	pthread_mutex_init(&display->mutex, NULL);
 	pthread_cond_init(&display->reader_cond, NULL);
@@ -931,6 +933,7 @@ queue_event(struct wl_display *display, int len)
 	struct wl_proxy *proxy;
 	struct wl_closure *closure;
 	const struct wl_message *message;
+	struct wl_event_queue *queue;
 
 	wl_connection_copy(display->connection, p, sizeof p);
 	id = p[0];
@@ -968,9 +971,14 @@ queue_event(struct wl_display *display, int len)
 	proxy->refcount++;
 	closure->proxy = proxy;
 
-	if (wl_list_empty(&proxy->queue->event_list))
-		pthread_cond_signal(&proxy->queue->cond);
-	wl_list_insert(proxy->queue->event_list.prev, &closure->link);
+	if (proxy == &display->proxy)
+		queue = &display->display_queue;
+	else
+		queue = proxy->queue;
+
+	if (wl_list_empty(&queue->event_list))
+		pthread_cond_signal(&queue->cond);
+	wl_list_insert(queue->event_list.prev, &closure->link);
 
 	return size;
 }
@@ -1143,10 +1151,19 @@ dispatch_queue(struct wl_display *display, struct wl_event_queue *queue)
 	if (display->last_error)
 		goto err;
 
-	for (count = 0; !wl_list_empty(&queue->event_list); count++) {
+	count = 0;
+	while (!wl_list_empty(&display->display_queue.event_list)) {
+		dispatch_event(display, &display->display_queue);
+		if (display->last_error)
+			goto err;
+		count++;
+	}
+
+	while (!wl_list_empty(&queue->event_list)) {
 		dispatch_event(display, queue);
 		if (display->last_error)
 			goto err;
+		count++;
 	}
 
 	return count;
-- 
1.8.4.2