feat(mysql): add support for Geometry subtypes

sqlx-mysql/src/types/geometry.rs

@@ -1,6 +1,10 @@
-use geo_types::Geometry;
+use geo_types::{
+    Error, Geometry, GeometryCollection, Line, LineString, MultiLineString, MultiPoint,
+    MultiPolygon, Point, Polygon, Rect, Triangle,
+};
 use geozero::wkb::{FromWkb, WkbDialect};
 use geozero::{GeozeroGeometry, ToWkb};
+use std::any::type_name;
 
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
@@ -10,23 +14,26 @@ use crate::protocol::text::ColumnType;
 use crate::types::Type;
 use crate::{MySql, MySqlTypeInfo, MySqlValueRef};
 
-/// Define a type that can be used to represent a `GEOMETRY` field.
-///
-/// Note: Only `Geometry<f64>` is implemented with geozero::GeozeroGeometry.
-impl Type<MySql> for Geometry<f64> {
-    fn type_info() -> MySqlTypeInfo {
-        // MySQL does not allow to execute with a Geometry parameter for now.
-        // MySQL reports: 1210 (HY000): Incorrect arguments to mysqld_stmt_execute
-        // MariaDB does not report errors but does not work properly.
-        // So we use the `Blob` type to pass Geometry parameters.
-        MySqlTypeInfo::binary(ColumnType::Blob)
-    }
+macro_rules! impl_mysql_type {
+    ($name:ident) => {
+        impl Type<MySql> for $name<f64> {
+            fn type_info() -> MySqlTypeInfo {
+                // MySQL does not allow to execute with a Geometry parameter for now.
+                // MySQL reports: 1210 (HY000): Incorrect arguments to mysqld_stmt_execute
+                // MariaDB does not report errors but does not work properly.
+                // So we use the `Blob` type to pass Geometry parameters.
+                MySqlTypeInfo::binary(ColumnType::Blob)
+            }
 
-    fn compatible(ty: &MySqlTypeInfo) -> bool {
-        ty.r#type == ColumnType::Geometry || <&[u8] as Type<MySql>>::compatible(ty)
-    }
+            fn compatible(ty: &MySqlTypeInfo) -> bool {
+                ty.r#type == ColumnType::Geometry || <&[u8] as Type<MySql>>::compatible(ty)
+            }
+        }
+    };
 }
 
+impl_mysql_type!(Geometry);
+
 const ENCODE_ERR: &str = "failed to encode value as Geometry to WKB; the most likely cause is that the value is not a valid geometry";
 
 impl Encode<'_, MySql> for Geometry<f64> {
@@ -48,3 +55,81 @@ impl Decode<'_, MySql> for Geometry<f64> {
         Ok(FromWkb::from_wkb(&mut bytes, WkbDialect::MySQL)?)
     }
 }
+
+macro_rules! impl_encode_subtype {
+    ($name:ident) => {
+        impl Encode<'_, MySql> for $name<f64> {
+            fn encode_by_ref(&self, buf: &mut Vec<u8>) -> IsNull {
+                Geometry::<f64>::$name(self.clone()).encode(buf)
+            }
+        }
+    };
+}
+
+macro_rules! impl_decode_subtype {
+    ($name:ident) => {
+        impl Decode<'_, MySql> for $name<f64> {
+            fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError> {
+                Ok(<Geometry<f64> as Decode<'_, MySql>>::decode(value)?.try_into()?)
+            }
+        }
+    };
+}
+
+macro_rules! impls_subtype {
+    ($name:ident) => {
+        impl_mysql_type!($name);
+        impl_encode_subtype!($name);
+        impl_decode_subtype!($name);
+    };
+    ($name:ident, $n:ident<$decode:ident> => $($c:tt)+) => {
+        impl_mysql_type!($name);
+        impl_encode_subtype!($name);
+
+        impl Decode<'_, MySql> for $name<f64> {
+            fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError> {
+                let $n = <$decode<f64> as Decode<'_, MySql>>::decode(value)?;
+
+                $($c)+
+            }
+        }
+    };
+}
+
+// All geometry types in MySQL:
+// GEOMETRY, POINT, LINESTRING, POLYGON, MULTIPOINT, MULTILINESTRING, MULTIPOLYGON, GEOMETRYCOLLECTION.
+// Line, Rect, Triangle can be encoded, but MySQL has no corresponding types so their decoding is unreachable.
+
+impls_subtype!(Point);
+impls_subtype!(LineString);
+impls_subtype!(Polygon);
+impls_subtype!(MultiPoint);
+impls_subtype!(MultiLineString);
+impls_subtype!(MultiPolygon);
+
+// GeometryCollection is a special case
+// Deprecated GeometryCollection::from(single_geom) produces unexpected results
+// TODO: remove following when GeometryCollection::from(single_geom) is removed
+
+macro_rules! geometry_collection_mismatch {
+    ($name:ident) => {
+        Err(Error::MismatchedGeometry {
+            expected: type_name::<GeometryCollection<f64>>(),
+            found: type_name::<$name<f64>>(),
+        }
+        .into())
+    };
+}
+
+impls_subtype!(GeometryCollection, g<Geometry> => match g {
+    Geometry::GeometryCollection(gc) => Ok(gc),
+    Geometry::Point(_) => geometry_collection_mismatch!(Point),
+    Geometry::Line(_) => geometry_collection_mismatch!(Line),
+    Geometry::LineString(_) => geometry_collection_mismatch!(LineString),
+    Geometry::Polygon(_) => geometry_collection_mismatch!(Polygon),
+    Geometry::MultiPoint(_) => geometry_collection_mismatch!(MultiPoint),
+    Geometry::MultiLineString(_) => geometry_collection_mismatch!(MultiLineString),
+    Geometry::MultiPolygon(_) => geometry_collection_mismatch!(MultiPolygon),
+    Geometry::Rect(_) => geometry_collection_mismatch!(Rect),
+    Geometry::Triangle(_) => geometry_collection_mismatch!(Triangle),
+});