From 301665360c49930e20f4cad3b357dc5f4d30a2d0 Mon Sep 17 00:00:00 2001
From: Ryan Leckey <ryan@launchbadge.com>
Date: Fri, 19 Feb 2021 21:41:42 -0800
Subject: [PATCH] wip: plan out transaction options, to mirror connect options

---
 sqlx-core/src/isolation_level.rs | 24 ++++++++++++++++++++++++
 sqlx-core/src/lib.rs             |  2 ++
 sqlx-mysql/src/error.rs          |  2 +-
 sqlx-mysql/src/lib.rs            |  5 +++++
 sqlx-mysql/src/transaction.rs    | 31 +++++++++++++++++++++++++++++++
 5 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 sqlx-core/src/isolation_level.rs
 create mode 100644 sqlx-mysql/src/transaction.rs

diff --git a/sqlx-core/src/isolation_level.rs b/sqlx-core/src/isolation_level.rs
new file mode 100644
index 00000000..ecdb7b5f
--- /dev/null
+++ b/sqlx-core/src/isolation_level.rs
@@ -0,0 +1,24 @@
+/// Transaction isolation level; controls the degree of locking that occurs
+/// when selecting data.
+///
+/// See <https://en.wikipedia.org/wiki/Isolation_(database_systems)#Isolation_levels>.
+///
+pub enum IsolationLevel {
+    /// The lowest isolation level. Dirty reads are allowed, so one transaction
+    /// may see **not yet committed** changes made by other transactions.
+    ReadUncommitted,
+
+    /// A `SELECT` query will only see data that has been committed before the
+    /// query began.
+    ///
+    /// However, two successive `SELECT` queries can see different data,
+    /// even though they are within a single transaction, if a concurrent
+    /// transaction has committed in-between.
+    ReadCommitted,
+
+    /// A `SELECT` query will only see data committed before the transaction
+    /// began.
+    RepeatableRead,
+
+    Serializable,
+}
diff --git a/sqlx-core/src/lib.rs b/sqlx-core/src/lib.rs
index b75234a6..f3f8bd99 100644
--- a/sqlx-core/src/lib.rs
+++ b/sqlx-core/src/lib.rs
@@ -31,6 +31,7 @@ pub mod encode;
 mod error;
 mod execute;
 mod executor;
+mod isolation_level;
 mod options;
 mod query_result;
 pub mod row;
@@ -65,6 +66,7 @@ pub use encode::Encode;
 pub use error::{DatabaseError, Error, Result};
 pub use execute::Execute;
 pub use executor::Executor;
+pub use isolation_level::IsolationLevel;
 pub use options::ConnectOptions;
 pub use query_result::QueryResult;
 pub use r#type::{Type, TypeDecode, TypeEncode};
diff --git a/sqlx-mysql/src/error.rs b/sqlx-mysql/src/error.rs
index 4a9fbd6b..36560fb9 100644
--- a/sqlx-mysql/src/error.rs
+++ b/sqlx-mysql/src/error.rs
@@ -5,7 +5,7 @@ use sqlx_core::DatabaseError;
 
 use crate::protocol::ErrPacket;
 
-/// An error returned from the MySQL database server.
+/// An error returned from the MySQL database.
 #[allow(clippy::module_name_repetitions)]
 #[derive(Debug)]
 pub struct MySqlDatabaseError(pub(crate) ErrPacket);
diff --git a/sqlx-mysql/src/lib.rs b/sqlx-mysql/src/lib.rs
index c7a16e8c..f56551a3 100644
--- a/sqlx-mysql/src/lib.rs
+++ b/sqlx-mysql/src/lib.rs
@@ -20,6 +20,8 @@
 #![allow(clippy::missing_errors_doc)]
 #![allow(clippy::missing_panics_doc)]
 
+use sqlx_core::Arguments;
+
 #[macro_use]
 mod stream;
 
@@ -35,6 +37,7 @@ mod query_result;
 mod raw_statement;
 mod raw_value;
 mod row;
+mod transaction;
 mod type_id;
 mod type_info;
 pub mod types;
@@ -53,3 +56,5 @@ pub use raw_value::{MySqlRawValue, MySqlRawValueFormat};
 pub use row::MySqlRow;
 pub use type_id::MySqlTypeId;
 pub use type_info::MySqlTypeInfo;
+
+pub type MySqlArguments<'a> = Arguments<'a, MySql>;
diff --git a/sqlx-mysql/src/transaction.rs b/sqlx-mysql/src/transaction.rs
new file mode 100644
index 00000000..7d22573b
--- /dev/null
+++ b/sqlx-mysql/src/transaction.rs
@@ -0,0 +1,31 @@
+use sqlx_core::IsolationLevel;
+
+#[derive(Debug)]
+pub struct MySqlTransactionOptions {
+    with_consistent_snapshot: bool,
+    read_only: bool,
+    isolation_level: IsolationLevel,
+}
+
+impl MySqlTransactionOptions {
+    pub fn read_only(&mut self) -> &mut Self {
+        self.read_only = true;
+        self
+    }
+
+    pub fn with_consistent_snapshot(&mut self) -> &mut Self {
+        self.with_consistent_snapshot = true;
+        self
+    }
+
+    pub fn isolation(&mut self, level: IsolationLevel) -> &mut Self {
+        self.isolation_level = level;
+        self
+    }
+}
+
+// impl MySqlTransactionOptions {
+//     pub fn begin(&self) -> MySqlTransaction {
+//         // [..]
+//     }
+// }