[PATCH weston] input: Don't use uninitialized variables in default_grab_pointer_focus()

Derek Foreman derekf at osg.samsung.com
Wed Apr 8 13:18:41 PDT 2015

If we have no pointer focus and weston_compositor_pick_view() returns NULL
default_grab_pointer_focus() will test the unset sx, sy output parameters
from weston_compositor_pick_view().

Instead, assume that since both pointers are NULL focus hasn't changed and
we don't need to update pointer focus.

Signed-off-by: Derek Foreman <derekf at osg.samsung.com>

This fixes an error reported by valgrind.  I think the patch is correct but
it does stop pointer->focus_signal from being emitted when focus switches
from NULL to NULL.  I think that shouldn't have happened anyway?

Initializing sx, sy to wl_fixed_from_int(0) would silence the warning too,
but I think this way is more correct...

 src/input.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/input.c b/src/input.c
index 142c670..18d1262 100644
--- a/src/input.c
+++ b/src/input.c
@@ -157,6 +157,9 @@ default_grab_pointer_focus(struct weston_pointer_grab *grab)
 					   pointer->x, pointer->y,
 					   &sx, &sy);
+	if (!pointer->focus && !view)
+		return;
 	if (pointer->focus != view || pointer->sx != sx || pointer->sy != sy)
 		weston_pointer_set_focus(pointer, view, sx, sy);

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