[mutter] wayland: don't try to use seat devices that aren't (yet) present

[Ray Strode <halfline src gnome org>]

commit 2aa6dcd9d8d2b15d2716afa6017180cdf1cb1a7d
Author: Ray Strode <rstrode redhat com>
Date:   Wed Feb 18 10:43:42 2015 -0500

    wayland: don't try to use seat devices that aren't (yet) present
    
    Before commit ac448bd42be8cf8e46cadd7e1a209491e33b1693 the pointer,
    keyboard, and touch objects were initialized when the seat was created.
    Now they're initialized later, when the clutter device manager finds and
    loads them.
    
    This commit makes sure we don't try to access those objects if they
    aren't initialized.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=744640

 src/wayland/meta-wayland-seat.c |   46 ++++++++++++++++++++++++++++-----------
 1 files changed, 33 insertions(+), 13 deletions(-)
---
diff --git a/src/wayland/meta-wayland-seat.c b/src/wayland/meta-wayland-seat.c
index 87525ac..f455ad8 100644
--- a/src/wayland/meta-wayland-seat.c
+++ b/src/wayland/meta-wayland-seat.c
@@ -44,7 +44,8 @@ seat_get_pointer (struct wl_client *client,
   MetaWaylandSeat *seat = wl_resource_get_user_data (resource);
   MetaWaylandPointer *pointer = &seat->pointer;
 
-  meta_wayland_pointer_create_new_resource (pointer, client, resource, id);
+  if ((seat->capabilities & WL_SEAT_CAPABILITY_POINTER) != 0)
+    meta_wayland_pointer_create_new_resource (pointer, client, resource, id);
 }
 
 static void
@@ -55,7 +56,8 @@ seat_get_keyboard (struct wl_client *client,
   MetaWaylandSeat *seat = wl_resource_get_user_data (resource);
   MetaWaylandKeyboard *keyboard = &seat->keyboard;
 
-  meta_wayland_keyboard_create_new_resource (keyboard, client, resource, id);
+  if ((seat->capabilities & WL_SEAT_CAPABILITY_KEYBOARD) != 0)
+    meta_wayland_keyboard_create_new_resource (keyboard, client, resource, id);
 }
 
 static void
@@ -66,7 +68,8 @@ seat_get_touch (struct wl_client *client,
   MetaWaylandSeat *seat = wl_resource_get_user_data (resource);
   MetaWaylandTouch *touch = &seat->touch;
 
-  meta_wayland_touch_create_new_resource (touch, client, resource, id);
+  if ((seat->capabilities & WL_SEAT_CAPABILITY_TOUCH) != 0)
+    meta_wayland_touch_create_new_resource (touch, client, resource, id);
 }
 
 static const struct wl_seat_interface seat_interface = {
@@ -350,6 +353,9 @@ meta_wayland_seat_handle_event (MetaWaylandSeat *seat,
 void
 meta_wayland_seat_repick (MetaWaylandSeat *seat)
 {
+  if ((seat->capabilities & WL_SEAT_CAPABILITY_POINTER) == 0)
+    return;
+
   meta_wayland_pointer_repick (&seat->pointer);
 }
 
@@ -357,6 +363,9 @@ void
 meta_wayland_seat_set_input_focus (MetaWaylandSeat    *seat,
                                    MetaWaylandSurface *surface)
 {
+  if ((seat->capabilities & WL_SEAT_CAPABILITY_KEYBOARD) == 0)
+    return;
+
   meta_wayland_keyboard_set_focus (&seat->keyboard, surface);
   meta_wayland_data_device_set_keyboard_focus (&seat->data_device);
 }
@@ -364,6 +373,9 @@ meta_wayland_seat_set_input_focus (MetaWaylandSeat    *seat,
 void
 meta_wayland_seat_update_cursor_surface (MetaWaylandSeat *seat)
 {
+  if ((seat->capabilities & WL_SEAT_CAPABILITY_POINTER) == 0)
+    return;
+
   meta_wayland_pointer_update_cursor_surface (&seat->pointer);
 }
 
@@ -374,21 +386,29 @@ meta_wayland_seat_get_grab_info (MetaWaylandSeat    *seat,
                                 gfloat             *x,
                                 gfloat             *y)
 {
-  ClutterEventSequence *sequence;
+  ClutterEventSequence *sequence = NULL;
+  gboolean can_grab_surface = FALSE;
 
-  sequence = meta_wayland_touch_find_grab_sequence (&seat->touch, surface, serial);
+  if ((seat->capabilities & WL_SEAT_CAPABILITY_TOUCH) != 0)
+    sequence = meta_wayland_touch_find_grab_sequence (&seat->touch, surface, serial);
 
   if (sequence)
-    meta_wayland_touch_get_press_coords (&seat->touch, sequence, x, y);
-  else if (meta_wayland_pointer_can_grab_surface (&seat->pointer, surface, serial))
     {
-      if (x)
-        *x = seat->pointer.grab_x;
-      if (y)
-        *y = seat->pointer.grab_y;
+      meta_wayland_touch_get_press_coords (&seat->touch, sequence, x, y);
     }
   else
-    return FALSE;
+    {
+      if ((seat->capabilities & WL_SEAT_CAPABILITY_POINTER) != 0)
+        can_grab_surface = meta_wayland_pointer_can_grab_surface (&seat->pointer, surface, serial);
+
+      if (can_grab_surface)
+        {
+          if (x)
+            *x = seat->pointer.grab_x;
+          if (y)
+            *y = seat->pointer.grab_y;
+        }
+    }
 
-  return TRUE;
+  return sequence || can_grab_surface;
 }