[librsvg] property_bag.rs: New functions lookup_and_parse(), lookup_length()

[Federico Mena Quintero <federico src gnome org>]

commit acbd87449144473ceddce8c419616e61cf25063d
Author: Federico Mena Quintero <federico gnome org>
Date:   Mon Feb 27 20:16:01 2017 -0600

    property_bag.rs: New functions lookup_and_parse(), lookup_length()
    
    The former does T::from_str() and uses T::default() for the parsing and
    default values.
    
    The latter parses an RsvgLength, and lets the caller specify a
    LengthDir.
    
    This makes the set_atts() functions a bit less verbose.

 rust/src/marker.rs       |   20 +++++-----------
 rust/src/property_bag.rs |   31 +++++++++++++++++++++++++
 rust/src/shapes.rs       |   56 ++++++++++++---------------------------------
 3 files changed, 52 insertions(+), 55 deletions(-)
---
diff --git a/rust/src/marker.rs b/rust/src/marker.rs
index b12a211..4f01b67 100644
--- a/rust/src/marker.rs
+++ b/rust/src/marker.rs
@@ -214,27 +214,19 @@ impl NodeMarker {
 
 impl NodeTrait for NodeMarker {
     fn set_atts (&self, _: &RsvgNode, _: *const RsvgHandle, pbag: *const RsvgPropertyBag) {
-        self.units.set (property_bag::lookup (pbag, "markerUnits").map_or (MarkerUnits::default (),
-                                                                           |v| MarkerUnits::from_str 
(&v).unwrap_or (MarkerUnits::default ())));
+        self.units.set (property_bag::lookup_and_parse (pbag, "markerUnits"));
 
-        self.ref_x.set (property_bag::lookup (pbag, "refX").map_or (RsvgLength::default (),
-                                                                    |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-        self.ref_y.set (property_bag::lookup (pbag, "refY").map_or (RsvgLength::default (),
-                                                                    |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
+        self.ref_x.set (property_bag::lookup_length (pbag, "refX", LengthDir::Horizontal));
+        self.ref_y.set (property_bag::lookup_length (pbag, "refY", LengthDir::Vertical));
 
         self.width.set (property_bag::lookup (pbag, "markerWidth").map_or (NodeMarker::get_default_size (),
                                                                            |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
         self.height.set (property_bag::lookup (pbag, "markerHeight").map_or (NodeMarker::get_default_size (),
                                                                              |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
 
-        self.orient.set (property_bag::lookup (pbag, "orient").map_or (MarkerOrient::default (),
-                                                                       |v| MarkerOrient::from_str 
(&v).unwrap_or (MarkerOrient::default ())));
-
-        self.aspect.set (property_bag::lookup (pbag, "preserveAspectRatio").map_or (AspectRatio::default (),
-                                                                                    |v| 
AspectRatio::from_str (&v).unwrap_or (AspectRatio::default ())));
-
-        self.vbox.set (property_bag::lookup (pbag, "viewBox").map_or (RsvgViewBox::default (),
-                                                                      |v| RsvgViewBox::from_str 
(&v).unwrap_or (RsvgViewBox::default ())));
+        self.orient.set (property_bag::lookup_and_parse (pbag, "orient"));
+        self.aspect.set (property_bag::lookup_and_parse (pbag, "preserveAspectRatio"));
+        self.vbox.set   (property_bag::lookup_and_parse (pbag, "viewBox"));
     }
 
     fn draw (&self, _: &RsvgNode, _: *const RsvgDrawingCtx, _: i32) {
diff --git a/rust/src/property_bag.rs b/rust/src/property_bag.rs
index 7a27383..1e296fd 100644
--- a/rust/src/property_bag.rs
+++ b/rust/src/property_bag.rs
@@ -1,8 +1,12 @@
 extern crate libc;
 extern crate glib;
 
+use std::str::FromStr;
+
 use self::glib::translate::*;
 
+use length::*;
+
 pub enum RsvgPropertyBag {}
 
 extern "C" {
@@ -20,3 +24,30 @@ pub fn lookup (pbag: *const RsvgPropertyBag, key: &str) -> Option<String> {
         from_glib_none (c_value)
     }
 }
+
+pub fn lookup_and_parse<T: Default + FromStr> (pbag: *const RsvgPropertyBag, key: &str) -> T {
+    let value = lookup (pbag, key);
+
+    if let Some (v) = value {
+        let result = T::from_str (&v);
+
+        if let Ok (r) = result {
+            r
+        } else {
+            // FIXME: Error is discarded here.  Figure out a way to propagate it upstream.
+            T::default ()
+        }
+    } else {
+        T::default ()
+    }
+}
+
+pub fn lookup_length (pbag: *const RsvgPropertyBag, key: &str, length_dir: LengthDir) -> RsvgLength {
+    let value = lookup (pbag, key);
+
+    if let Some (v) = value {
+        RsvgLength::parse (&v, length_dir)
+    } else {
+        RsvgLength::default ()
+    }
+}
diff --git a/rust/src/shapes.rs b/rust/src/shapes.rs
index 1176a48..14a4c07 100644
--- a/rust/src/shapes.rs
+++ b/rust/src/shapes.rs
@@ -195,17 +195,10 @@ impl NodeLine {
 
 impl NodeTrait for NodeLine {
     fn set_atts (&self, _: &RsvgNode, _: *const RsvgHandle, pbag: *const RsvgPropertyBag) {
-        self.x1.set (property_bag::lookup (pbag, "x1").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-
-        self.y1.set (property_bag::lookup (pbag, "y1").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
-
-        self.x2.set (property_bag::lookup (pbag, "x2").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-
-        self.y2.set (property_bag::lookup (pbag, "y2").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
+        self.x1.set (property_bag::lookup_length (pbag, "x1", LengthDir::Horizontal));
+        self.y1.set (property_bag::lookup_length (pbag, "y1", LengthDir::Vertical));
+        self.x2.set (property_bag::lookup_length (pbag, "x2", LengthDir::Horizontal));
+        self.y2.set (property_bag::lookup_length (pbag, "y2", LengthDir::Vertical));
     }
 
     fn draw (&self, node: &RsvgNode, draw_ctx: *const RsvgDrawingCtx, dominate: i32) {
@@ -257,17 +250,10 @@ impl NodeRect {
 
 impl NodeTrait for NodeRect {
     fn set_atts (&self, _: &RsvgNode, _: *const RsvgHandle, pbag: *const RsvgPropertyBag) {
-        self.x.set (property_bag::lookup (pbag, "x").map_or (RsvgLength::default (),
-                                                             |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-
-        self.y.set (property_bag::lookup (pbag, "y").map_or (RsvgLength::default (),
-                                                             |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
-
-        self.w.set (property_bag::lookup (pbag, "width").map_or (RsvgLength::default (),
-                                                                 |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-
-        self.h.set (property_bag::lookup (pbag, "height").map_or (RsvgLength::default (),
-                                                                  |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
+        self.x.set (property_bag::lookup_length (pbag, "x", LengthDir::Horizontal));
+        self.y.set (property_bag::lookup_length (pbag, "y", LengthDir::Vertical));
+        self.w.set (property_bag::lookup_length (pbag, "width", LengthDir::Horizontal));
+        self.h.set (property_bag::lookup_length (pbag, "height", LengthDir::Vertical));
 
         self.rx.set (property_bag::lookup (pbag, "rx").map_or (None,
                                                                |v| Some (RsvgLength::parse (&v, 
LengthDir::Horizontal))));
@@ -440,14 +426,9 @@ impl NodeCircle {
 
 impl NodeTrait for NodeCircle {
     fn set_atts (&self, _: &RsvgNode, _: *const RsvgHandle, pbag: *const RsvgPropertyBag) {
-        self.cx.set (property_bag::lookup (pbag, "cx").map_or (RsvgLength::default (),
-                                                              |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-
-        self.cy.set (property_bag::lookup (pbag, "cy").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
-
-        self.r.set (property_bag::lookup (pbag, "r").map_or (RsvgLength::default (),
-                                                             |v| RsvgLength::parse (&v, LengthDir::Both)));
+        self.cx.set (property_bag::lookup_length (pbag, "cx", LengthDir::Horizontal));
+        self.cy.set (property_bag::lookup_length (pbag, "cy", LengthDir::Vertical));
+        self.r.set  (property_bag::lookup_length (pbag, "r", LengthDir::Both));
     }
 
     fn draw (&self, node: &RsvgNode, draw_ctx: *const RsvgDrawingCtx, dominate: i32) {
@@ -485,17 +466,10 @@ impl NodeEllipse {
 
 impl NodeTrait for NodeEllipse {
     fn set_atts (&self, _: &RsvgNode, _: *const RsvgHandle, pbag: *const RsvgPropertyBag) {
-        self.cx.set (property_bag::lookup (pbag, "cx").map_or (RsvgLength::default (),
-                                                              |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-
-        self.cy.set (property_bag::lookup (pbag, "cy").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
-    
-        self.rx.set (property_bag::lookup (pbag, "rx").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Horizontal)));
-
-        self.ry.set (property_bag::lookup (pbag, "ry").map_or (RsvgLength::default (),
-                                                               |v| RsvgLength::parse (&v, 
LengthDir::Vertical)));
+        self.cx.set (property_bag::lookup_length (pbag, "cx", LengthDir::Horizontal));
+        self.cy.set (property_bag::lookup_length (pbag, "cy", LengthDir::Vertical));
+        self.rx.set (property_bag::lookup_length (pbag, "rx", LengthDir::Horizontal));
+        self.ry.set (property_bag::lookup_length (pbag, "ry", LengthDir::Vertical));
     }
 
     fn draw (&self, node: &RsvgNode, draw_ctx: *const RsvgDrawingCtx, dominate: i32) {