[librsvg: 26/30] Handle cairo errors when creating a mask

[Marge Bot <marge-bot src gnome org>]

commit 68c435b7e2afab9692c8827454887e1facc93e19
Author: Federico Mena Quintero <federico gnome org>
Date:   Mon Jun 21 20:56:59 2021 -0500

    Handle cairo errors when creating a mask
    
    Part-of: <https://gitlab.gnome.org/GNOME/librsvg/-/merge_requests/516>

 src/drawing_ctx.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/drawing_ctx.rs b/src/drawing_ctx.rs
index a196bc70..0da7acf1 100644
--- a/src/drawing_ctx.rs
+++ b/src/drawing_ctx.rs
@@ -809,10 +809,12 @@ impl DrawingCtx {
                             &bbox,
                             acquired_nodes,
                         )
-                        .map(|mask_surf| {
+                        .and_then(|mask_surf| {
                             if let Some(surf) = mask_surf {
                                 self.cr.set_matrix(affines.compositing.into());
-                                self.cr.mask_surface(&surf, 0.0, 0.0);
+                                Ok(self.cr.mask_surface(&surf, 0.0, 0.0)?)
+                            } else {
+                                Ok(())
                             }
                         })
                         .map(|_: ()| bbox)