Uuid support for MySQL (#536)

* feat: uuid decoder for mysql, patterned on postgres

* feat: Add uuid on mysql encoding

* fix: encode after converting to bytes

* fix: use the byte decoder on uuids

* fix: remove unused import

* feat: Adds mysql encoding/decoding support for Hyphenated uuid

* fix: uncommented feature flag line

* fix: unresolved import

* fix: use sqlx string type for binary uuid

Co-authored-by: Ian Hume <Humeian@me.com>

sqlx-core/src/mysql/types/mod.rs

@@ -55,6 +55,15 @@
 //! |---------------------------------------|------------------------------------------------------|
 //! | `rust_decimal::Decimal`               | DECIMAL                                              |
 //!
+//! ### [`uuid`](https://crates.io/crates/uuid)
+//!
+//! Requires the `uuid` Cargo feature flag.
+//!
+//! | Rust type                             | MySQL type(s)                                        |
+//! |---------------------------------------|------------------------------------------------------|
+//! | `uuid::Uuid`                          | BYTE(16), VARCHAR, CHAR, TEXT                        |
+//! | `uuid::adapter::Hyphenated`           | CHAR(36)                                             |
+//!
 //! ### [`json`](https://crates.io/crates/json)
 //!
 //! Requires the `json` Cargo feature flag.
@@ -88,5 +97,8 @@ mod chrono;
 #[cfg(feature = "time")]
 mod time;
 
+#[cfg(feature = "uuid")]
+mod uuid;
+
 #[cfg(feature = "json")]
 mod json;

sqlx-core/src/mysql/types/uuid.rs

@@ -0,0 +1,58 @@
+use uuid::{adapter::Hyphenated, Uuid};
+
+use crate::decode::Decode;
+use crate::encode::{Encode, IsNull};
+use crate::error::BoxDynError;
+use crate::mysql::io::MySqlBufMutExt;
+use crate::mysql::protocol::text::{ColumnFlags, ColumnType};
+use crate::mysql::{MySql, MySqlTypeInfo, MySqlValueRef};
+use crate::types::Type;
+
+impl Type<MySql> for Uuid {
+    fn type_info() -> MySqlTypeInfo {
+        MySqlTypeInfo::binary(ColumnType::String)
+    }
+}
+
+impl Encode<'_, MySql> for Uuid {
+    fn encode_by_ref(&self, buf: &mut Vec<u8>) -> IsNull {
+        buf.put_bytes_lenenc(self.as_bytes());
+
+        IsNull::No
+    }
+}
+
+impl Decode<'_, MySql> for Uuid {
+    fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError> {
+        // delegate to the &[u8] type to decode from MySQL
+        let bytes = <&[u8] as Decode<MySql>>::decode(value)?;
+
+        // construct a Uuid from the returned bytes
+        Uuid::from_slice(bytes).map_err(Into::into)
+    }
+}
+
+impl Type<MySql> for Hyphenated {
+    fn type_info() -> MySqlTypeInfo {
+        MySqlTypeInfo {
+            r#type: ColumnType::String, // CHAR
+            char_set: 224,              // utf8mb4_unicode_ci
+            flags: ColumnFlags::empty(),
+        }
+    }
+}
+
+impl Encode<'_, MySql> for Hyphenated {
+    fn encode_by_ref(&self, buf: &mut Vec<u8>) -> IsNull {
+        buf.put_str_lenenc(&self.to_string());
+
+        IsNull::No
+    }
+}
+
+impl Decode<'_, MySql> for Hyphenated {
+    fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError> {
+        let uuid: Result<Uuid, BoxDynError> = Uuid::parse_str(value.as_str()?).map_err(Into::into);
+        Ok(uuid?.to_hyphenated())
+    }
+}