[librsvg: 39/90] PathBuilder::to_cairo() - Check the cr.status after completing the path

[Federico Mena Quintero <federico src gnome org>]

commit 3ae3bb1cb3dbc19038017d20e17562692238ee2e
Author: Federico Mena Quintero <federico gnome org>
Date:   Thu Mar 14 13:42:44 2019 -0600

    PathBuilder::to_cairo() - Check the cr.status after completing the path
    
    Any of the individual path commands may cause the cr to enter an
    error state, for example, if they come with coordinates outside of Cairo's supported range.
    
    The *next* call to the cr will probably be something that actually
    checks the status (i.e. in cairo-rs), and we don't want to panic
    there.
    
    (In the worst case, Cairo will throw out-of-memory with a super-long
    path, but this is the correct place to catch that.)

 rsvg_internals/src/path_builder.rs | 18 +++++++++++++++++-
 rsvg_internals/src/shapes.rs       |  2 +-
 2 files changed, 18 insertions(+), 2 deletions(-)
---
diff --git a/rsvg_internals/src/path_builder.rs b/rsvg_internals/src/path_builder.rs
index 077f3e8f..db133bfc 100644
--- a/rsvg_internals/src/path_builder.rs
+++ b/rsvg_internals/src/path_builder.rs
@@ -355,10 +355,26 @@ impl PathBuilder {
         &self.path_commands
     }
 
-    pub fn to_cairo(&self, cr: &cairo::Context) {
+    pub fn to_cairo(&self, cr: &cairo::Context) -> Result<(), cairo::Status> {
         for s in &self.path_commands {
             s.to_cairo(cr);
         }
+
+        // We check the cr's status right after feeding it a new path for a few reasons:
+        //
+        // * Any of the individual path commands may cause the cr to enter an error state,
+        //   for example, if they come with coordinates outside of Cairo's supported range.
+        //
+        // * The *next* call to the cr will probably be something that actually checks
+        //   the status (i.e. in cairo-rs), and we don't want to panic there.
+
+        let status = cr.status();
+
+        if status == cairo::Status::Success {
+            Ok(())
+        } else {
+            Err(status)
+        }
     }
 }
 
diff --git a/rsvg_internals/src/shapes.rs b/rsvg_internals/src/shapes.rs
index a9ca0a8d..f7a9fd1d 100644
--- a/rsvg_internals/src/shapes.rs
+++ b/rsvg_internals/src/shapes.rs
@@ -27,7 +27,7 @@ fn render_path_builder(
     draw_ctx.with_discrete_layer(node, values, clipping, &mut |dc| {
         let cr = dc.get_cairo_context();
 
-        builder.to_cairo(&cr);
+        builder.to_cairo(&cr)?;
 
         if clipping {
             cr.set_fill_rule(cairo::FillRule::from(values.clip_rule));