feat(python): add in-memory mode

bindings/python/build.rs

@@ -1,4 +1,3 @@
 fn main() {
     pyo3_build_config::use_pyo3_cfgs();
-    println!("cargo::rustc-check-cfg=cfg(allocator, values(\"default\", \"mimalloc\"))");
 }

bindings/python/src/lib.rs

@@ -4,6 +4,7 @@ use limbo_core::IO;
 use pyo3::prelude::*;
 use pyo3::types::PyList;
 use pyo3::types::PyTuple;
+use std::cell::RefCell;
 use std::rc::Rc;
 use std::sync::{Arc, Mutex};
 
@@ -78,7 +79,7 @@ pub struct Cursor {
     #[pyo3(get)]
     rowcount: i64,
 
-    smt: Option<Arc<Mutex<limbo_core::Statement>>>,
+    smt: Option<Rc<RefCell<limbo_core::Statement>>>,
 }
 
 // SAFETY: The limbo_core crate guarantees that `Cursor` is thread-safe.
@@ -90,26 +91,33 @@ impl Cursor {
     #[pyo3(signature = (sql, parameters=None))]
     pub fn execute(&mut self, sql: &str, parameters: Option<Py<PyTuple>>) -> Result<Self> {
         let stmt_is_dml = stmt_is_dml(sql);
+        let stmt_is_ddl = stmt_is_ddl(sql);
 
-        let conn_lock =
+        let statement = self.conn.conn.prepare(sql).map_err(|e| {
-            self.conn.conn.lock().map_err(|_| {
-                PyErr::new::<OperationalError, _>("Failed to acquire connection lock")
-            })?;
-
-        let statement = conn_lock.prepare(sql).map_err(|e| {
             PyErr::new::<ProgrammingError, _>(format!("Failed to prepare statement: {:?}", e))
         })?;
 
-        self.smt = Some(Arc::new(Mutex::new(statement)));
+        let stmt = Rc::new(RefCell::new(statement));
 
-        // TODO: use stmt_is_dml to set rowcount
+        // For DDL and DML statements,
-        if stmt_is_dml {
+        // we need to execute the statement immediately
-            return Err(PyErr::new::<NotSupportedError, _>(
+        if stmt_is_ddl || stmt_is_dml {
-                "DML statements (INSERT/UPDATE/DELETE) are not fully supported in this version",
+            loop {
-            )
+                match stmt.borrow_mut().step().map_err(|e| {
-            .into());
+                    PyErr::new::<OperationalError, _>(format!("Step error: {:?}", e))
+                })? {
+                    limbo_core::RowResult::IO => {
+                        self.conn.io.run_once().map_err(|e| {
+                            PyErr::new::<OperationalError, _>(format!("IO error: {:?}", e))
+                        })?;
+                    }
+                    _ => break,
+                }
+            }
         }
 
+        self.smt = Some(stmt);
+
         Ok(Cursor {
             smt: self.smt.clone(),
             conn: self.conn.clone(),
@@ -121,11 +129,8 @@ impl Cursor {
 
     pub fn fetchone(&mut self, py: Python) -> Result<Option<PyObject>> {
         if let Some(smt) = &self.smt {
-            let mut smt_lock = smt.lock().map_err(|_| {
-                PyErr::new::<OperationalError, _>("Failed to acquire statement lock")
-            })?;
             loop {
-                match smt_lock.step().map_err(|e| {
+                match smt.borrow_mut().step().map_err(|e| {
                     PyErr::new::<OperationalError, _>(format!("Step error: {:?}", e))
                 })? {
                     limbo_core::StepResult::Row(row) => {
@@ -157,14 +162,9 @@ impl Cursor {
 
     pub fn fetchall(&mut self, py: Python) -> Result<Vec<PyObject>> {
         let mut results = Vec::new();
-
         if let Some(smt) = &self.smt {
-            let mut smt_lock = smt.lock().map_err(|_| {
-                PyErr::new::<OperationalError, _>("Failed to acquire statement lock")
-            })?;
-
             loop {
-                match smt_lock.step().map_err(|e| {
+                match smt.borrow_mut().step().map_err(|e| {
                     PyErr::new::<OperationalError, _>(format!("Step error: {:?}", e))
                 })? {
                     limbo_core::StepResult::Row(row) => {
@@ -221,11 +221,17 @@ fn stmt_is_dml(sql: &str) -> bool {
     sql.starts_with("INSERT") || sql.starts_with("UPDATE") || sql.starts_with("DELETE")
 }
 
+fn stmt_is_ddl(sql: &str) -> bool {
+    let sql = sql.trim();
+    let sql = sql.to_uppercase();
+    sql.starts_with("CREATE") || sql.starts_with("ALTER") || sql.starts_with("DROP")
+}
+
 #[pyclass]
 #[derive(Clone)]
 pub struct Connection {
-    conn: Arc<Mutex<Rc<limbo_core::Connection>>>,
+    conn: Rc<limbo_core::Connection>,
-    io: Arc<limbo_core::PlatformIO>,
+    io: Arc<dyn limbo_core::IO>,
 }
 
 // SAFETY: The limbo_core crate guarantees that `Connection` is thread-safe.
@@ -263,16 +269,24 @@ impl Connection {
 #[allow(clippy::arc_with_non_send_sync)]
 #[pyfunction]
 pub fn connect(path: &str) -> Result<Connection> {
-    let io = Arc::new(limbo_core::PlatformIO::new().map_err(|e| {
+    match path {
-        PyErr::new::<InterfaceError, _>(format!("IO initialization failed: {:?}", e))
+        ":memory:" => {
-    })?);
+            let io: Arc<dyn limbo_core::IO> = Arc::new(limbo_core::MemoryIO::new()?);
-    let db = limbo_core::Database::open_file(io.clone(), path)
+            let db = limbo_core::Database::open_file(io.clone(), path).map_err(|e| {
-        .map_err(|e| PyErr::new::<DatabaseError, _>(format!("Failed to open database: {:?}", e)))?;
+                PyErr::new::<DatabaseError, _>(format!("Failed to open database: {:?}", e))
-    let conn: Rc<limbo_core::Connection> = db.connect();
+            })?;
-    Ok(Connection {
+            let conn: Rc<limbo_core::Connection> = db.connect();
-        conn: Arc::new(Mutex::new(conn)),
+            Ok(Connection { conn, io })
-        io,
+        }
-    })
+        path => {
+            let io: Arc<dyn limbo_core::IO> = Arc::new(limbo_core::PlatformIO::new()?);
+            let db = limbo_core::Database::open_file(io.clone(), path).map_err(|e| {
+                PyErr::new::<DatabaseError, _>(format!("Failed to open database: {:?}", e))
+            })?;
+            let conn: Rc<limbo_core::Connection> = db.connect();
+            Ok(Connection { conn, io })
+        }
+    }
 }
 
 fn row_to_py(py: Python, row: &limbo_core::Row) -> PyObject {

bindings/python/tests/test_database.py

@@ -27,6 +27,20 @@ def test_fetchall_select_user_ids(provider):
     assert user_ids == [(1,), (2,)]
 
 
+@pytest.mark.parametrize("provider", ["sqlite3", "limbo"])
+def test_in_memory_fetchone_select_all_users(provider):
+    conn = connect(provider, ":memory:")
+    cursor = conn.cursor()
+    cursor.execute("CREATE TABLE users (id INT PRIMARY KEY, username TEXT)")
+    cursor.execute("INSERT INTO users VALUES (1, 'alice')")
+ 
+    cursor.execute("SELECT * FROM users")
+
+    alice = cursor.fetchone()
+    assert alice
+    assert alice == (1, "alice")
+
+
 @pytest.mark.parametrize("provider", ["sqlite3", "limbo"])
 def test_fetchone_select_all_users(provider):
     conn = connect(provider, "tests/database.db")