From 4cbd894803f239af3e320aece24521aeb325cbd2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Sat, 4 Jan 2020 23:27:59 +0100
Subject: [PATCH] wayland: use a low priority FDM hook to flush the wayland
 socket

This way, we don't have to manually insert flushes in code paths that
may execute outside of a wl_display_dispatch_pending().

(Those that execute inside a wl_display_dispatch_pending() are subject
to the flush performed at the end of the normal wayland FDM handler).
---
 render.c  |  2 --
 wayland.c | 15 ++++++++++++++-
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/render.c b/render.c
index 023b904c..1bbe2853 100644
--- a/render.c
+++ b/render.c
@@ -852,7 +852,6 @@ grid_render(struct terminal *term)
     }
 
     wl_surface_commit(term->window->surface);
-    wayl_flush(term->wl);
 
 #if TIME_FRAME_RENDERING
     struct timeval end_time;
@@ -1141,7 +1140,6 @@ render_xcursor_update(struct wayland *wayl, const struct terminal *term)
     wl_callback_add_listener(wayl->pointer.xcursor_callback, &xcursor_listener, wayl);
 
     wl_surface_commit(wayl->pointer.surface);
-    wayl_flush(wayl);
 }
 
 static void
diff --git a/wayland.c b/wayland.c
index b8edd505..ee304bd3 100644
--- a/wayland.c
+++ b/wayland.c
@@ -556,6 +556,13 @@ static const struct wl_registry_listener registry_listener = {
     .global_remove = &handle_global_remove,
 };
 
+static void
+fdm_hook(struct fdm *fdm, void *data)
+{
+    struct wayland *wayl = data;
+    wayl_flush(wayl);
+}
+
 static bool
 fdm_wayl(struct fdm *fdm, int fd, int events, void *data)
 {
@@ -574,7 +581,6 @@ fdm_wayl(struct fdm *fdm, int fd, int events, void *data)
         return false;
     }
 
-    wayl_flush(wayl);
     return event_count != -1;
 }
 
@@ -730,6 +736,11 @@ wayl_init(const struct config *conf, struct fdm *fdm)
         goto out;
     }
 
+    if (!fdm_hook_add(fdm, &fdm_hook, wayl, FDM_HOOK_PRIORITY_LOW)) {
+        LOG_ERR("failed to add FDM hook");
+        goto out;
+    }
+
     return wayl;
 
 out:
@@ -755,6 +766,8 @@ wayl_destroy(struct wayland *wayl)
 
     tll_free(wayl->terms);
 
+    fdm_hook_del(wayl->fdm, &fdm_hook, FDM_HOOK_PRIORITY_LOW);
+
     if (wayl->kbd.repeat.fd != -1)
         fdm_del(wayl->fdm, wayl->kbd.repeat.fd);