[librsvg] NodeStop: validate "offset" using a validation function

[Federico Mena Quintero <federico src gnome org>]

commit f46c92493a95c6a223fef138e16400cfe9756a00
Author: Federico Mena Quintero <federico gnome org>
Date:   Tue Sep 5 09:21:17 2017 -0500

    NodeStop: validate "offset" using a validation function

 rust/src/stop.rs |   45 ++++++++++++++++++++++++++-------------------
 1 files changed, 26 insertions(+), 19 deletions(-)
---
diff --git a/rust/src/stop.rs b/rust/src/stop.rs
index fd51511..3d61f2f 100644
--- a/rust/src/stop.rs
+++ b/rust/src/stop.rs
@@ -12,6 +12,7 @@ use handle::RsvgHandle;
 use length::*;
 use node::*;
 use opacity::*;
+use parsers::Parse;
 use property_bag;
 use property_bag::*;
 use state::RsvgState;
@@ -38,27 +39,33 @@ impl NodeStop {
     }
 }
 
-impl NodeTrait for NodeStop {
-    fn set_atts (&self, node: &RsvgNode, handle: *const RsvgHandle, pbag: *const RsvgPropertyBag) -> 
NodeResult {
-        let offset_length: RsvgLength = property_bag::parse_or_default (pbag, "offset", LengthDir::Both, 
None)?;
-        match offset_length.unit {
-            LengthUnit::Default |
-            LengthUnit::Percent => {
-                let mut offset = offset_length.length;
-
-                if offset < 0.0 {
-                    offset = 0.0;
-                } else if offset > 1.0 {
-                    offset = 1.0;
-                }
+fn validate_offset(length: RsvgLength) -> Result<RsvgLength, AttributeError> {
+    match length.unit {
+        LengthUnit::Default |
+        LengthUnit::Percent => {
+            let mut offset = length.length;
 
-                self.offset.set (offset);
-            },
-
-            _ => {
-                return Err (NodeError::value_error ("offset", "stop offset must be in default or percent 
units"));
+            if offset < 0.0 {
+                offset = 0.0;
+            } else if offset > 1.0 {
+                offset = 1.0;
             }
+
+            Ok(RsvgLength::new(offset, LengthUnit::Default, LengthDir::Both))
+        },
+
+        _ => {
+            Err (AttributeError::Value ("stop offset must be in default or percent units".to_string()))
         }
+    }
+}
+
+impl NodeTrait for NodeStop {
+    fn set_atts (&self, node: &RsvgNode, handle: *const RsvgHandle, pbag: *const RsvgPropertyBag) -> 
NodeResult {
+        let length = property_bag::parse_or_default (pbag, "offset", LengthDir::Both,
+                                                     Some(validate_offset))?;
+        assert! (length.unit == LengthUnit::Default || length.unit == LengthUnit::Percent);
+        self.offset.set (length.length);
 
         let state = node.get_state ();