Check for a found touch before attempting to paint it

Signed-off-by: Chase Douglas <chase.douglas@canonical.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/multitouch.c b/multitouch.c
index 53c52de..817de22 100644
--- a/multitouch.c
+++ b/multitouch.c
@@ -341,6 +341,12 @@ static void paint_touch_update(struct multitouch *mt, XIDeviceEvent *event)
 {
     struct touchpoint *t = find_touch(mt, event->detail);
 
+    if (!t)
+    {
+        error("Could not find touch in %s\n", __FUNCTION__);
+        return;
+    }
+
     cairo_save(mt->cr);
     cairo_set_source_rgba(mt->cr, 0, 0, 0, t->owned ? 1 : .5);
     cairo_move_to(mt->cr, t->x, t->y);
@@ -359,6 +365,12 @@ static void paint_touch_end(struct multitouch *mt, XIDeviceEvent *event)
     int rsize = 30;
     struct touchpoint *t = find_touch(mt, event->detail);
 
+    if (!t)
+    {
+        error("Could not find touch in %s\n", __FUNCTION__);
+        return;
+    }
+
     t->x = event->event_x;
     t->y = event->event_y;
     t->state = TSTATE_END;