[gtk+/wip/baedert/gl: 71/85] gl renderer: Avoid crashing tooltips

[Timm Bäder <baedert src gnome org>]

commit d747437bb6950a49c306d56d2ee1c6c444ddfd64
Author: Timm Bäder <mail baedert org>
Date:   Tue Dec 5 17:49:25 2017 +0100

    gl renderer: Avoid crashing tooltips

 gsk/gl/gskglrenderops.c |   27 +++++++++++++++------------
 1 files changed, 15 insertions(+), 12 deletions(-)
---
diff --git a/gsk/gl/gskglrenderops.c b/gsk/gl/gskglrenderops.c
index 0b5a7dc..8e96888 100644
--- a/gsk/gl/gskglrenderops.c
+++ b/gsk/gl/gskglrenderops.c
@@ -74,19 +74,22 @@ ops_set_clip (RenderOpBuilder      *builder,
   RenderOp *last_op;
   GskRoundedRect prev_clip;
 
-  last_op = &g_array_index (builder->render_ops, RenderOp, builder->render_ops->len - 1);
-
-  if (last_op->op == OP_CHANGE_CLIP)
-    {
-      last_op->clip = *clip;
-    }
-  else
+  if (builder->render_ops->len > 0)
     {
-      RenderOp op;
-
-      op.op = OP_CHANGE_CLIP;
-      op.clip = *clip;
-      g_array_append_val (builder->render_ops, op);
+      last_op = &g_array_index (builder->render_ops, RenderOp, builder->render_ops->len - 1);
+
+      if (last_op->op == OP_CHANGE_CLIP)
+        {
+          last_op->clip = *clip;
+        }
+      else
+        {
+          RenderOp op;
+
+          op.op = OP_CHANGE_CLIP;
+          op.clip = *clip;
+          g_array_append_val (builder->render_ops, op);
+        }
     }
 
   if (builder->current_program != NULL)