sqlx-core/src/encode.rs

@@ -176,7 +176,6 @@ impl<'q, T, DB: Database> Encode<'q, DB> for Cow<'_, T>
 where
     for<'a> &'a T: Encode<'q, DB>,
     T: ToOwned,
-    T: ?Sized,
 {
     #[inline]
     fn encode(self, buf: &mut <DB as Database>::ArgumentBuffer<'q>) -> Result<IsNull, BoxDynError> {

sqlx-mysql/src/types/str.rs

@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use crate::decode::Decode;
 use crate::encode::{Encode, IsNull};
 use crate::error::BoxDynError;
@@ -72,3 +74,18 @@ impl Decode<'_, MySql> for String {
         <&str as Decode<MySql>>::decode(value).map(ToOwned::to_owned)
     }
 }
+
+impl Encode<'_, MySql> for Cow<'_, str> {
+    fn encode_by_ref(&self, buf: &mut Vec<u8>) -> Result<IsNull, BoxDynError> {
+        match self {
+            Cow::Borrowed(str) => <&str as Encode<MySql>>::encode(*str, buf),
+            Cow::Owned(str) => <&str as Encode<MySql>>::encode(&**str, buf),
+        }
+    }
+}
+
+impl Encode<'_, MySql> for Cow<'_, [u8]> {
+    fn encode_by_ref(&self, buf: &mut Vec<u8>) -> Result<IsNull, BoxDynError> {
+        <&[u8] as Encode<MySql>>::encode(self.as_ref(), buf)
+    }
+}

sqlx-postgres/src/types/str.rs

@@ -105,3 +105,18 @@ impl Decode<'_, Postgres> for String {
         Ok(value.as_str()?.to_owned())
     }
 }
+
+impl Encode<'_, Postgres> for Cow<'_, str> {
+    fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> Result<IsNull, BoxDynError> {
+        match self {
+            Cow::Borrowed(str) => <&str as Encode<Postgres>>::encode(*str, buf),
+            Cow::Owned(str) => <&str as Encode<Postgres>>::encode(&**str, buf),
+        }
+    }
+}
+
+impl Encode<'_, Postgres> for Cow<'_, [u8]> {
+    fn encode_by_ref(&self, buf: &mut PgArgumentBuffer) -> Result<IsNull, BoxDynError> {
+        <&[u8] as Encode<Postgres>>::encode(self.as_ref(), buf)
+    }
+}

sqlx-sqlite/src/types/str.rs

@@ -77,3 +77,37 @@ impl<'r> Decode<'r, Sqlite> for String {
         value.text().map(ToOwned::to_owned)
     }
 }
+
+impl<'q> Encode<'q, Sqlite> for Cow<'q, str> {
+    fn encode(self, args: &mut Vec<SqliteArgumentValue<'q>>) -> Result<IsNull, BoxDynError> {
+        args.push(SqliteArgumentValue::Text(self));
+
+        Ok(IsNull::No)
+    }
+
+    fn encode_by_ref(
+        &self,
+        args: &mut Vec<SqliteArgumentValue<'q>>,
+    ) -> Result<IsNull, BoxDynError> {
+        args.push(SqliteArgumentValue::Text(self.clone()));
+
+        Ok(IsNull::No)
+    }
+}
+
+impl<'q> Encode<'q, Sqlite> for Cow<'q, [u8]> {
+    fn encode(self, args: &mut Vec<SqliteArgumentValue<'q>>) -> Result<IsNull, BoxDynError> {
+        args.push(SqliteArgumentValue::Blob(self));
+
+        Ok(IsNull::No)
+    }
+
+    fn encode_by_ref(
+        &self,
+        args: &mut Vec<SqliteArgumentValue<'q>>,
+    ) -> Result<IsNull, BoxDynError> {
+        args.push(SqliteArgumentValue::Blob(self.clone()));
+
+        Ok(IsNull::No)
+    }
+}