feat(types): add support for prost messages

Adds a wrapper type for prost messages to help deserialize bytea values
directly into the protobuf structure.

postgres-types/Cargo.toml

@@ -26,6 +26,7 @@ with-uuid-0_8 = ["uuid-08"]
 with-uuid-1 = ["uuid-1"]
 with-time-0_2 = ["time-02"]
 with-time-0_3 = ["time-03"]
+with-prost-0_12 = ["prost-012"]
 
 [dependencies]
 bytes = "1.0"
@@ -52,3 +53,4 @@ uuid-1 = { version = "1.0", package = "uuid", optional = true }
 time-02 = { version = "0.2", package = "time", optional = true }
 time-03 = { version = "0.3", package = "time", default-features = false, optional = true }
 smol_str-01 = { version = "0.1.23", package = "smol_str", default-features = false, optional = true }
+prost-012 = { version = "0.12", package = "prost", optional = true }

postgres-types/src/lib.rs

@@ -199,6 +199,10 @@ pub use postgres_derive::{FromSql, ToSql};
 
 #[cfg(feature = "with-serde_json-1")]
 pub use crate::serde_json_1::Json;
+
+#[cfg(feature = "with-prost-0_12")]
+pub use crate::prost_012::Protobuf;
+
 use crate::type_gen::{Inner, Other};
 
 #[doc(inline)]
@@ -276,6 +280,8 @@ mod eui48_1;
 mod geo_types_06;
 #[cfg(feature = "with-geo-types-0_7")]
 mod geo_types_07;
+#[cfg(feature = "with-prost-0_12")]
+mod prost_012;
 #[cfg(feature = "with-serde_json-1")]
 mod serde_json_1;
 #[cfg(feature = "with-smol_str-01")]

postgres-types/src/prost_012.rs

@@ -0,0 +1,28 @@
+use crate::{accepts, to_sql_checked, types, FromSql, IsNull, ToSql, Type};
+use bytes::BytesMut;
+use prost_012::Message;
+use std::error::Error;
+
+/// A wrapper type to allow for `prost::Message` types to convert to & from Postgres BYTEA values.
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+pub struct Protobuf<T>(pub T);
+
+impl<T: Message + Default> FromSql<'_> for Protobuf<T> {
+    fn from_sql(_ty: &Type, raw: &[u8]) -> Result<Self, Box<dyn Error + Sync + Send>> {
+        Ok(Self(T::decode(types::bytea_from_sql(raw))?))
+    }
+
+    accepts!(BYTEA);
+}
+
+impl<T: Message> ToSql for Protobuf<T> {
+    fn to_sql(&self, ty: &Type, w: &mut BytesMut) -> Result<IsNull, Box<dyn Error + Sync + Send>> {
+        <&[u8] as ToSql>::to_sql(&&*self.0.encode_to_vec(), ty, w)
+    }
+
+    fn accepts(ty: &Type) -> bool {
+        <&[u8] as ToSql>::accepts(ty)
+    }
+
+    to_sql_checked!();
+}