Merge #64

64: Support 'POINT EMPTY' conversion to geo_types r=michaelkirk a=rmanoka

- [x] I agree to follow the project's [code of conduct](https://github.com/georust/geo/blob/master/CODE_OF_CONDUCT.md).
- [x] I added an entry to `CHANGES.md` if knowledge of this change could be valuable to users.
---

closes  #61 

Co-authored-by: Rajsekar Manokaran <rajsekar@gmail.com>

CHANGES.md

@@ -3,6 +3,9 @@
 ## Unreleased
 
 * Add new entries here
+* Support `POINT EMPTY` in conversion to `geo_types`.
+  Converts to `MultiPoint([])`.
+  * <https://github.com/georust/wkt/pull/64>
 
 ## 0.9.1
 

benches/parse.rs

@@ -8,14 +8,14 @@ fn criterion_benchmark(c: &mut criterion::Criterion) {
     c.bench_function("parse small", |bencher| {
         let s = include_str!("./small.wkt");
         bencher.iter(|| {
-            let _ = wkt::Wkt::from_str(s).unwrap();
+            let _ = wkt::Wkt::<f64>::from_str(s).unwrap();
         });
     });
 
     c.bench_function("parse big", |bencher| {
         let s = include_str!("./big.wkt");
         bencher.iter(|| {
-            let _ = wkt::Wkt::from_str(s).unwrap();
+            let _ = wkt::Wkt::<f64>::from_str(s).unwrap();
         });
     });
 }

src/conversion.rs

@@ -288,7 +288,14 @@ where
 
     fn try_from(geometry: Geometry<T>) -> Result<Self, Self::Error> {
         Ok(match geometry {
-            Geometry::Point(g) => geo_types::Geometry::Point(g.try_into()?),
+            Geometry::Point(g) => {
+                // Special case as `geo::Point` can't be empty
+                if g.0.is_some() {
+                    geo_types::Point::try_from(g)?.into()
+                } else {
+                    geo_types::MultiPoint(vec![]).into()
+                }
+            }
             Geometry::LineString(g) => geo_types::Geometry::LineString(g.into()),
             Geometry::Polygon(g) => geo_types::Geometry::Polygon(g.into()),
             Geometry::MultiLineString(g) => geo_types::Geometry::MultiLineString(g.into()),
@@ -358,8 +365,8 @@ mod tests {
 
     #[test]
     fn convert_empty_point() {
-        let point = Point(None).as_item();
-        let res: Result<geo_types::Geometry<f64>, Error> = point.try_into();
+        let point = Point(None);
+        let res: Result<geo_types::Point<f64>, Error> = point.try_into();
         assert!(res.is_err());
     }
 

src/deserialize.rs

@@ -160,15 +160,17 @@ where
     use serde::Deserialize;
     Wkt::deserialize(deserializer).and_then(|wkt: Wkt<T>| {
         use std::convert::TryFrom;
-        geo_types::Point::try_from(wkt)
-            .map(|p| Some(p))
-            .or_else(|e| {
-                if let crate::conversion::Error::PointConversionError = e {
-                    // map a WKT: 'POINT EMPTY' to an `Option<geo_types::Point>::None`
-                    return Ok(None);
+        geo_types::Geometry::try_from(wkt)
+            .map_err(D::Error::custom)
+            .and_then(|geom| {
+                use geo_types::Geometry::*;
+                match geom {
+                    Point(p) => Ok(Some(p)),
+                    MultiPoint(mp) if mp.0.len() == 0 => Ok(None),
+                    _ => geo_types::Point::try_from(geom)
+                        .map(Some)
+                        .map_err(D::Error::custom),
                 }
-
-                Err(D::Error::custom(e))
             })
     })
 }