implement raw WAL write api

tests/integration/functions/test_wal_api.rs

@@ -0,0 +1,57 @@
+use rusqlite::types::Value;
+
+use crate::common::{limbo_exec_rows, TempDatabase};
+
+#[test]
+fn test_wal_frame_count() {
+    let db = TempDatabase::new_empty(false);
+    let conn = db.connect_limbo();
+    assert_eq!(conn.wal_frame_count().unwrap(), 0);
+    conn.execute("CREATE TABLE t(x INTEGER PRIMARY KEY, y)")
+        .unwrap();
+    assert_eq!(conn.wal_frame_count().unwrap(), 2);
+    conn.execute("INSERT INTO t VALUES (10, 10), (5, 1)")
+        .unwrap();
+    assert_eq!(conn.wal_frame_count().unwrap(), 3);
+    conn.execute("INSERT INTO t VALUES (1024, randomblob(4096 * 10))")
+        .unwrap();
+    assert_eq!(conn.wal_frame_count().unwrap(), 15);
+}
+
+#[test]
+fn test_wal_frame_transfer_no_schema_changes() {
+    let db1 = TempDatabase::new_empty(false);
+    let conn1 = db1.connect_limbo();
+    let db2 = TempDatabase::new_empty(false);
+    let conn2 = db2.connect_limbo();
+    conn1
+        .execute("CREATE TABLE t(x INTEGER PRIMARY KEY, y)")
+        .unwrap();
+    conn2
+        .execute("CREATE TABLE t(x INTEGER PRIMARY KEY, y)")
+        .unwrap();
+    conn1
+        .execute("INSERT INTO t VALUES (10, 10), (5, 1)")
+        .unwrap();
+    conn1
+        .execute("INSERT INTO t VALUES (1024, randomblob(4096 * 10))")
+        .unwrap();
+    assert_eq!(conn1.wal_frame_count().unwrap(), 15);
+    let mut frame = [0u8; 24 + 4096];
+    conn2.wal_insert_begin().unwrap();
+    for frame_id in 1..=conn1.wal_frame_count().unwrap() as u32 {
+        let c = conn1.wal_get_frame(frame_id, &mut frame).unwrap();
+        db1.io.wait_for_completion(c).unwrap();
+        conn2.wal_insert_frame(frame_id, &frame).unwrap();
+    }
+    conn2.wal_insert_end().unwrap();
+    assert_eq!(conn2.wal_frame_count().unwrap(), 15);
+    assert_eq!(
+        limbo_exec_rows(&db2, &conn2, "SELECT x, length(y) FROM t"),
+        vec![
+            vec![Value::Integer(5), Value::Integer(1)],
+            vec![Value::Integer(10), Value::Integer(2)],
+            vec![Value::Integer(1024), Value::Integer(40960)],
+        ]
+    );
+}