create udf utility file

scalar_udf.go

@@ -122,12 +122,6 @@ func RegisterScalarUDFSet(c *sql.Conn, name string, functions ...ScalarFunc) err
 	return err
 }
 
-func setFuncError(function_info C.duckdb_function_info, msg string) {
-	err := C.CString(msg)
-	C.duckdb_scalar_function_set_error(function_info, err)
-	C.duckdb_free(unsafe.Pointer(err))
-}
-
 //export scalar_udf_callback
 func scalar_udf_callback(function_info C.duckdb_function_info, input C.duckdb_data_chunk, output C.duckdb_vector) {
 	extraInfo := C.duckdb_scalar_function_get_extra_info(function_info)
@@ -198,10 +192,8 @@ func scalar_udf_callback(function_info C.duckdb_function_info, input C.duckdb_da
 }
 
 //export scalar_udf_delete_callback
-func scalar_udf_delete_callback(extraInfo unsafe.Pointer) {
-	h := (*cgo.Handle)(extraInfo)
-	h.Value().(unpinner).unpin()
-	h.Delete()
+func scalar_udf_delete_callback(info unsafe.Pointer) {
+	udf_delete_callback(info)
 }
 
 func registerInputParams(config ScalarFuncConfig, f C.duckdb_scalar_function) error {

udf_util.go

@@ -0,0 +1,37 @@
+package duckdb
+
+/*
+#include <duckdb.h>
+*/
+import "C"
+
+import (
+	"runtime"
+	"runtime/cgo"
+	"unsafe"
+)
+
+type pinnedValue[T any] struct {
+	pinner *runtime.Pinner
+	value  T
+}
+
+type unpinner interface {
+	unpin()
+}
+
+func (v pinnedValue[T]) unpin() {
+	v.pinner.Unpin()
+}
+
+func setFuncError(function_info C.duckdb_function_info, msg string) {
+	err := C.CString(msg)
+	C.duckdb_scalar_function_set_error(function_info, err)
+	C.duckdb_free(unsafe.Pointer(err))
+}
+
+func udf_delete_callback(info unsafe.Pointer) {
+	h := (*cgo.Handle)(info)
+	h.Value().(unpinner).unpin()
+	h.Delete()
+}