Merge #622

622: Add optional `arbitrary` integration in geo-types. r=michaelkirk a=frewsxcv

- [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.
---

Extracted from #532

If people feel this is too niche, this could also just be a separate crate that lives in this repo or a separate one 🤷🏻 


Co-authored-by: Corey Farwell <coreyf@rwell.org>

geo-types/CHANGES.md

@@ -11,6 +11,8 @@
   * <https://github.com/georust/geo/pull/616>
 * Add specific details about conversion failures in the newly public `geo_types::Error`
   * <https://github.com/georust/geo/pull/614>
+* Add optional `arbitrary` feature for integration with the [arbitrary](https://github.com/rust-fuzz/arbitrary) crate
+  * <https://github.com/georust/geo/pull/622>
 
 ## 0.7.0
 

geo-types/Cargo.toml

@@ -15,6 +15,7 @@ use-rstar = ["rstar", "approx"]
 
 [dependencies]
 approx = { version = "0.4.0", optional = true }
+arbitrary = { version = "1", optional = true }
 num-traits = "0.2"
 serde = { version = "1", optional = true, features = ["derive"] }
 # Prefer `use-rstar` feature rather than enabling rstar directly.

geo-types/src/arbitrary.rs

@@ -0,0 +1,108 @@
+use std::mem;
+use crate::{
+    CoordFloat, Coordinate, Geometry, GeometryCollection, LineString, MultiLineString, MultiPoint,
+    MultiPolygon, Point, Polygon, Rect, Triangle,
+};
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for Coordinate<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        let x = u.arbitrary::<T>()?;
+        let y = u.arbitrary::<T>()?;
+        Ok(Coordinate { x, y })
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for Point<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        u.arbitrary::<Coordinate<T>>().map(Point)
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for LineString<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        let coords = u.arbitrary::<Vec<Coordinate<T>>>()?;
+
+        if coords.len() < 2 {
+            return Err(arbitrary::Error::IncorrectFormat);
+        }
+
+        Ok(LineString(coords))
+    }
+
+    fn size_hint(_depth: usize) -> (usize, Option<usize>) {
+        (mem::size_of::<T>() * 2, None)
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for Polygon<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        Ok(Polygon::new(
+            u.arbitrary::<LineString<T>>()?,
+            u.arbitrary::<Vec<LineString<T>>>()?,
+        ))
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for MultiPoint<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        u.arbitrary::<Vec<Point<T>>>().map(MultiPoint)
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for MultiLineString<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        u.arbitrary::<Vec<LineString<T>>>().map(MultiLineString)
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for MultiPolygon<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        u.arbitrary::<Vec<Polygon<T>>>().map(MultiPolygon)
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a>
+    for GeometryCollection<T>
+{
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        u.arbitrary()
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for Rect<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        Ok(Rect::new(
+            u.arbitrary::<Coordinate<T>>()?,
+            u.arbitrary::<Coordinate<T>>()?,
+        ))
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for Triangle<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        Ok(Triangle(
+            u.arbitrary::<Coordinate<T>>()?,
+            u.arbitrary::<Coordinate<T>>()?,
+            u.arbitrary::<Coordinate<T>>()?,
+        ))
+    }
+}
+
+impl<'a, T: arbitrary::Arbitrary<'a> + CoordFloat> arbitrary::Arbitrary<'a> for Geometry<T> {
+    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
+        let n = u.int_in_range(0..=8)?;
+
+        Ok(match n {
+            0 => Geometry::Point(u.arbitrary()?),
+            1 => Geometry::LineString(u.arbitrary()?),
+            2 => Geometry::Polygon(u.arbitrary()?),
+            3 => Geometry::MultiPoint(u.arbitrary()?),
+            4 => Geometry::MultiLineString(u.arbitrary()?),
+            5 => Geometry::MultiPolygon(u.arbitrary()?),
+            6 => Geometry::GeometryCollection(u.arbitrary()?),
+            7 => Geometry::Triangle(u.arbitrary()?),
+            8 => Geometry::Rect(u.arbitrary()?),
+            _ => unreachable!(),
+        })
+    }
+}

geo-types/src/lib.rs

@@ -35,10 +35,12 @@
 //! The following optional [Cargo features] are available:
 //!
 //! - `approx`: Allows geometry types to be checked for approximate equality with [approx]
+//! - `arbitrary`: Allows geometry types to be created from unstructured input with [arbitrary]
 //! - `serde`: Allows geometry types to be serialized and deserialized with [Serde]
 //! - `use-rstar`: Allows geometry types to be inserted into [rstar] R*-trees
 //!
 //! [approx]: https://github.com/brendanzab/approx
+//! [arbitrary]: https://github.com/rust-fuzz/arbitrary
 //! [Cargo features]: https://doc.rust-lang.org/cargo/reference/features.html
 //! [GeoRust]: https://georust.org
 //! [GEOS]: https://trac.osgeo.org/geos
@@ -123,6 +125,9 @@ pub use error::Error;
 #[macro_use]
 mod macros;
 
+#[cfg(feature = "arbitrary")]
+mod arbitrary;
+
 #[cfg(feature = "rstar")]
 #[doc(hidden)]
 pub mod private_utils;