From 239705a6feefaddf90be9541a054ebd8c8c10d81 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Wed, 9 Mar 2016 10:31:58 +0100
Subject: [PATCH] xwayland: add a server sync before repeating keys

Key repeat is handled by the X server, but input events need to be
processed and forwarded by the Wayland compositor first.

Make sure the Wayland compositor is actually processing events, to
avoid repeating keys in Xwayland while the Wayland compositor cannot
deal with input events for whatever reason, thus not dispatching key
release events, leading to repeated keys while the user has already
released the key.

Bugzilla: https://bugzilla.gnome.org/show_bug.cgi?id=762618
Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
---
 hw/xwayland/xwayland-input.c | 76 +++++++++++++++++++++++++++++++++++-
 hw/xwayland/xwayland.h       |  2 +
 2 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
index d1866811a..20dd92b7f 100644
--- a/hw/xwayland/xwayland-input.c
+++ b/hw/xwayland/xwayland-input.c
@@ -41,6 +41,11 @@
         (miPointerPtr)dixLookupPrivate(&(dev)->devPrivates, miPointerPrivKey): \
         (miPointerPtr)dixLookupPrivate(&(GetMaster(dev, MASTER_POINTER))->devPrivates, miPointerPrivKey))
 
+struct sync_pending {
+    struct xorg_list l;
+    DeviceIntPtr pending_dev;
+};
+
 static void
 xwl_pointer_control(DeviceIntPtr device, PtrCtrl *ctrl)
 {
@@ -519,6 +524,61 @@ keyboard_handle_modifiers(void *data, struct wl_keyboard *keyboard,
     }
 }
 
+static void
+remove_sync_pending(DeviceIntPtr dev)
+{
+    struct xwl_seat *xwl_seat = dev->public.devicePrivate;
+    struct sync_pending *p, *npd;
+
+    xorg_list_for_each_entry_safe(p, npd, &xwl_seat->sync_pending, l) {
+        if (p->pending_dev == dev) {
+            xorg_list_del(&xwl_seat->sync_pending);
+            free (p);
+            return;
+        }
+    }
+}
+
+static void
+sync_callback(void *data, struct wl_callback *callback, uint32_t serial)
+{
+    DeviceIntPtr dev = (DeviceIntPtr) data;
+
+    remove_sync_pending(dev);
+    wl_callback_destroy(callback);
+}
+
+static const struct wl_callback_listener sync_listener = {
+   sync_callback
+};
+
+static Bool
+keyboard_check_repeat (DeviceIntPtr dev, XkbSrvInfoPtr xkbi, unsigned key)
+{
+    struct xwl_seat *xwl_seat = dev->public.devicePrivate;
+    struct xwl_screen *xwl_screen = xwl_seat->xwl_screen;
+    struct wl_callback *callback;
+    struct sync_pending *p;
+
+    xorg_list_for_each_entry(p, &xwl_seat->sync_pending, l) {
+        if (p->pending_dev == dev) {
+            ErrorF("Key repeat discarded, Wayland compositor doesn't "
+                   "seem to be processing events fast enough!\n");
+
+            return FALSE;
+        }
+    }
+
+    p = xnfalloc(sizeof(struct sync_pending));
+    p->pending_dev = dev;
+    callback = wl_display_sync (xwl_screen->display);
+    xorg_list_add(&p->l, &xwl_seat->sync_pending);
+
+    wl_callback_add_listener(callback, &sync_listener, dev);
+
+    return TRUE;
+}
+
 static void
 keyboard_handle_repeat_info (void *data, struct wl_keyboard *keyboard,
                              int32_t rate, int32_t delay)
@@ -709,6 +769,7 @@ seat_handle_capabilities(void *data, struct wl_seat *seat,
                          enum wl_seat_capability caps)
 {
     struct xwl_seat *xwl_seat = data;
+    DeviceIntPtr master;
 
     if (caps & WL_SEAT_CAPABILITY_POINTER && xwl_seat->wl_pointer == NULL) {
         xwl_seat->wl_pointer = wl_seat_get_pointer(seat);
@@ -741,12 +802,18 @@ seat_handle_capabilities(void *data, struct wl_seat *seat,
             ActivateDevice(xwl_seat->keyboard, TRUE);
         }
         EnableDevice(xwl_seat->keyboard, TRUE);
+        xwl_seat->keyboard->key->xkbInfo->checkRepeat = keyboard_check_repeat;
+        master = GetMaster(xwl_seat->keyboard, MASTER_KEYBOARD);
+        if (master)
+            master->key->xkbInfo->checkRepeat = keyboard_check_repeat;
     } else if (!(caps & WL_SEAT_CAPABILITY_KEYBOARD) && xwl_seat->wl_keyboard) {
         wl_keyboard_release(xwl_seat->wl_keyboard);
         xwl_seat->wl_keyboard = NULL;
 
-        if (xwl_seat->keyboard)
+        if (xwl_seat->keyboard) {
+            remove_sync_pending(xwl_seat->keyboard);
             DisableDevice(xwl_seat->keyboard, TRUE);
+        }
     }
 
     if (caps & WL_SEAT_CAPABILITY_TOUCH && xwl_seat->wl_touch == NULL) {
@@ -807,12 +874,14 @@ create_input_device(struct xwl_screen *xwl_screen, uint32_t id, uint32_t version
     wl_array_init(&xwl_seat->keys);
 
     xorg_list_init(&xwl_seat->touches);
+    xorg_list_init(&xwl_seat->sync_pending);
 }
 
 void
 xwl_seat_destroy(struct xwl_seat *xwl_seat)
 {
     struct xwl_touch *xwl_touch, *next_xwl_touch;
+    struct sync_pending *p, *npd;
 
     xorg_list_for_each_entry_safe(xwl_touch, next_xwl_touch,
                                   &xwl_seat->touches, link_touch) {
@@ -820,6 +889,11 @@ xwl_seat_destroy(struct xwl_seat *xwl_seat)
         free(xwl_touch);
     }
 
+    xorg_list_for_each_entry_safe(p, npd, &xwl_seat->sync_pending, l) {
+        xorg_list_del(&xwl_seat->sync_pending);
+        free (p);
+    }
+
     wl_seat_destroy(xwl_seat->seat);
     wl_surface_destroy(xwl_seat->cursor);
     if (xwl_seat->cursor_frame_cb)
diff --git a/hw/xwayland/xwayland.h b/hw/xwayland/xwayland.h
index 67b30cb94..5c053d912 100644
--- a/hw/xwayland/xwayland.h
+++ b/hw/xwayland/xwayland.h
@@ -138,6 +138,8 @@ struct xwl_seat {
     size_t keymap_size;
     char *keymap;
     struct wl_surface *keyboard_focus;
+
+    struct xorg_list sync_pending;
 };
 
 struct xwl_output {