// driverArgs converts arguments from callers of Stmt.Exec and
// Stmt.Query into driver Values.
//
// The statement ds may be nil, if no statement is available.
func driverArgs(ds *driverStmt, args []interface{}) ([]driver.Value, error) {
dargs := make([]driver.Value, len(args))
var si driver.Stmt
if ds != nil {
si = ds.si
}
cc, ok := si.(driver.ColumnConverter)
// Normal path, for a driver.Stmt that is not a ColumnConverter.
if !ok {
for n, arg := range args {
var err error
dargs[n], err = driver.DefaultParameterConverter.ConvertValue(arg)
if err != nil {
return nil, fmt.Errorf("sql: converting Exec argument #%d's type: %v", n, err)
}
}
return dargs, nil
}
// Let the Stmt convert its own arguments.
for n, arg := range args {
// First, see if the value itself knows how to convert
// itself to a driver type. For example, a NullString
// struct changing into a string or nil.
if svi, ok := arg.(driver.Valuer); ok {
sv, err := svi.Value()
if err != nil {
return nil, fmt.Errorf("sql: argument index %d from Value: %v", n, err)
}
if !driver.IsValue(sv) {
return nil, fmt.Errorf("sql: argument index %d: non-subset type %T returned from Value", n, sv)
}
arg = sv
}
// Second, ask the column to sanity check itself. For
// example, drivers might use this to make sure that
// an int64 values being inserted into a 16-bit
// integer field is in range (before getting
// truncated), or that a nil can't go into a NOT NULL
// column before going across the network to get the
// same error.
var err error
ds.Lock()
dargs[n], err = cc.ColumnConverter(n).ConvertValue(arg)
ds.Unlock()
if err != nil {
return nil, fmt.Errorf("sql: converting argument #%d's type: %v", n, err)
}
if !driver.IsValue(dargs[n]) {
return nil, fmt.Errorf("sql: driver ColumnConverter error converted %T to unsupported type %T",
arg, dargs[n])
}
}
return dargs, nil
}
func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
if driver.IsValue(v) {
return v, nil
}
rv := reflect.ValueOf(v)
switch rv.Kind() {
case reflect.Ptr:
// indirect pointers
if rv.IsNil() {
return nil, nil
}
return c.ConvertValue(rv.Elem().Interface())
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return rv.Int(), nil
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32:
return int64(rv.Uint()), nil
case reflect.Uint64:
u64 := rv.Uint()
if u64 >= 1<<63 {
return strconv.FormatUint(u64, 10), nil
}
return int64(u64), nil
case reflect.Float32, reflect.Float64:
return rv.Float(), nil
}
return nil, fmt.Errorf("unsupported type %T, a %s", v, rv.Kind())
}