sqlite: let ConnInitFunc use ExecScript

Got about 1 minute into using this before I figured out how to improve
it. :)

Signed-off-by: David Crawshaw <crawshaw@tailscale.com>

Author: crawshaw

sqlite.go

@@ -14,13 +14,7 @@
 // tracing, use the Connector function:
 //
 //	connInitFunc := func(ctx context.Context, conn driver.ConnPrepareContext) error {
-//		called++
-//		stmt, err := conn.PrepareContext(ctx, "PRAGMA journal_mode=WAL;")
-//		if err != nil {
-//			return err
-//		}
-//		_, err = stmt.(driver.StmtExecContext).ExecContext(ctx, nil)
-//		return err
+//		return sqlite.ExecScript(conn.(sqlite.SQLConn), "PRAGMA journal_mode=WAL;")
 //	}
 //	db, err = sql.OpenDB(sqlite.Connector(sqliteURI, connInitFunc, nil))
 //
@@ -112,7 +106,7 @@ type TraceFunc func(prepCtx context.Context, query string, duration time.Duratio
 
 // ConnInitFunc is a function called by the driver on new connections.
 //
-// The conn can be used to execute queries.
+// The conn can be used to execute queries, and implements SQLConn.
 // Any error return closes the conn and passes the error to database/sql.
 type ConnInitFunc func(ctx context.Context, conn driver.ConnPrepareContext) error
 
@@ -279,6 +273,9 @@ func (c *conn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, e
 	return &connTx{c: c}, nil
 }
 
+// Raw is so ConnInitFunc can cast to SQLConn.
+func (c *conn) Raw(fn func(interface{}) error) error { return fn(c) }
+
 type connTx struct {
 	c *conn
 }

sqlite_test.go

@@ -617,13 +617,7 @@ func TestConnInit(t *testing.T) {
 	uri := "file:" + t.TempDir() + "/test.db"
 	connInitFunc := func(ctx context.Context, conn driver.ConnPrepareContext) error {
 		called++
-		stmt, err := conn.PrepareContext(ctx, "PRAGMA journal_mode=WAL;")
-		if err != nil {
-			return err
-		}
-		_, err = stmt.(driver.StmtExecContext).ExecContext(ctx, nil)
-		stmt.Close()
-		return err
+		return ExecScript(conn.(SQLConn), "PRAGMA journal_mode=WAL;")
 	}
 	db := sql.OpenDB(Connector(uri, connInitFunc, nil))
 	conn, err := db.Conn(context.Background())