replication: support SAVEPOINT

Now that we support savepoints in the server, let's also allow them
in the client library.

Refs tursodatabase/libsql-experimental-python#6

libsql/src/replication/connection.rs

@@ -57,6 +57,15 @@ impl State {
 
             (State::TxnReadOnly, StmtKind::TxnEnd) | (State::Txn, StmtKind::TxnEnd) => State::Init,
 
+            // Savepoint only makes sense within a transaction and doesn't change the transaction kind
+            (State::TxnReadOnly, StmtKind::Savepoint) => State::TxnReadOnly,
+            (State::Txn, StmtKind::Savepoint) => State::Txn,
+            (_, StmtKind::Savepoint) => State::Invalid,
+            // Releasing a savepoint only makes sense inside a transaction and it doesn't change its state
+            (State::TxnReadOnly, StmtKind::Release) => State::TxnReadOnly,
+            (State::Txn, StmtKind::Release) => State::Txn,
+            (_, StmtKind::Release) => State::Invalid,
+
             (state, StmtKind::Other | StmtKind::Write | StmtKind::Read) => state,
             (State::Invalid, _) => State::Invalid,
 

libsql/src/replication/parser.rs

@@ -26,6 +26,8 @@ pub enum StmtKind {
     TxnEnd,
     Read,
     Write,
+    Savepoint,
+    Release,
     Other,
 }
 
@@ -52,7 +54,13 @@ impl StmtKind {
                 Some(Self::TxnBeginReadOnly)
             }
             Cmd::Stmt(Stmt::Begin { .. }) => Some(Self::TxnBegin),
-            Cmd::Stmt(Stmt::Commit { .. } | Stmt::Rollback { .. }) => Some(Self::TxnEnd),
+            Cmd::Stmt(
+                Stmt::Commit { .. }
+                | Stmt::Rollback {
+                    savepoint_name: None,
+                    ..
+                },
+            ) => Some(Self::TxnEnd),
             Cmd::Stmt(
                 Stmt::CreateVirtualTable { tbl_name, .. }
                 | Stmt::CreateTable {
@@ -100,6 +108,12 @@ impl StmtKind {
                 temporary: false, ..
             }) => Some(Self::Write),
             Cmd::Stmt(Stmt::DropView { .. }) => Some(Self::Write),
+            Cmd::Stmt(Stmt::Savepoint(_)) => Some(Self::Savepoint),
+            Cmd::Stmt(Stmt::Release(_))
+            | Cmd::Stmt(Stmt::Rollback {
+                savepoint_name: Some(_),
+                ..
+            }) => Some(Self::Release),
             _ => None,
         }
     }
@@ -168,6 +182,22 @@ impl StmtKind {
             },
         }
     }
+
+    /// Returns `true` if the stmt kind is [`Savepoint`].
+    ///
+    /// [`Savepoint`]: StmtKind::Savepoint
+    #[must_use]
+    pub fn is_savepoint(&self) -> bool {
+        matches!(self, Self::Savepoint)
+    }
+
+    /// Returns `true` if the stmt kind is [`Release`].
+    ///
+    /// [`Release`]: StmtKind::Release
+    #[must_use]
+    pub fn is_release(&self) -> bool {
+        matches!(self, Self::Release)
+    }
 }
 
 impl Statement {