clip: Fix clip-equal to handle one or the other being NULL/all-clipped

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/cairo-clip.c b/src/cairo-clip.c
index b01093efb..4058879fd 100644
--- a/src/cairo-clip.c
+++ b/src/cairo-clip.c
@@ -346,6 +346,16 @@ _cairo_clip_equal (const cairo_clip_t *clip_a,
     if (clip_a == clip_b)
 	return TRUE;
 
+    /* or just one of them? */
+    if (clip_a == NULL || clip_b == NULL ||
+	_cairo_clip_is_all_clipped (clip_a) ||
+	_cairo_clip_is_all_clipped (clip_b))
+    {
+	return FALSE;
+    }
+
+    /* We have a pair of normal clips, check their contents */
+
     if (clip_a->num_boxes != clip_b->num_boxes)
 	return FALSE;