Beispiel #1
0
func baseType(t reflect.Type, expected reflect.Kind) (reflect.Type, error) {
	t = reflectx.Deref(t)
	if t.Kind() != expected {
		return nil, fmt.Errorf("expected %s but got %s", expected, t.Kind())
	}
	return t, nil
}
Beispiel #2
0
func (r *Row) scanAny(dest interface{}, structOnly bool) error {
	if r.err != nil {
		return r.err
	}
	defer r.rows.Close()

	v := reflect.ValueOf(dest)
	if v.Kind() != reflect.Ptr {
		return errors.New("must pass a pointer, not a value, to StructScan destination")
	}
	if v.IsNil() {
		return errors.New("nil pointer passed to StructScan destination")
	}

	base := reflectx.Deref(v.Type())
	scannable := isScannable(base)

	if structOnly && scannable {
		return structOnlyError(base)
	}

	columns, err := r.Columns()
	if err != nil {
		return err
	}

	if scannable && len(columns) > 1 {
		return fmt.Errorf("scannable dest type %s with >1 columns (%d) in result", base.Kind(), len(columns))
	}

	if scannable {
		return r.Scan(dest)
	}

	m := r.Mapper

	fields := m.TraversalsByName(v.Type(), columns)
	// if we are not unsafe and are missing fields, return an error
	if f, err := missingFields(fields); err != nil && !r.unsafe {
		return fmt.Errorf("missing destination name %s", columns[f])
	}
	values := make([]interface{}, len(columns))

	err = fieldsByTraversal(v, fields, values, true)
	if err != nil {
		return err
	}
	// scan into the struct field pointers and append to our results
	return r.Scan(values...)
}
Beispiel #3
0
// scanAll scans all rows into a destination, which must be a slice of any
// type.  If the destination slice type is a Struct, then StructScan will be
// used on each row.  If the destination is some other kind of base type, then
// each row must only have one column which can scan into that type.  This
// allows you to do something like:
//
//    rows, _ := db.Query("select id from people;")
//    var ids []int
//    scanAll(rows, &ids, false)
//
// and ids will be a list of the id results.  I realize that this is a desirable
// interface to expose to users, but for now it will only be exposed via changes
// to `Get` and `Select`.  The reason that this has been implemented like this is
// this is the only way to not duplicate reflect work in the new API while
// maintaining backwards compatibility.
func scanAll(rows rowsi, dest interface{}, structOnly bool) error {
	var v, vp reflect.Value

	value := reflect.ValueOf(dest)

	// json.Unmarshal returns errors for these
	if value.Kind() != reflect.Ptr {
		return errors.New("must pass a pointer, not a value, to StructScan destination")
	}
	if value.IsNil() {
		return errors.New("nil pointer passed to StructScan destination")
	}
	direct := reflect.Indirect(value)

	slice, err := baseType(value.Type(), reflect.Slice)
	if err != nil {
		return err
	}

	isPtr := slice.Elem().Kind() == reflect.Ptr
	base := reflectx.Deref(slice.Elem())
	scannable := isScannable(base)

	if structOnly && scannable {
		return structOnlyError(base)
	}

	columns, err := rows.Columns()
	if err != nil {
		return err
	}

	// if it's a base type make sure it only has 1 column;  if not return an error
	if scannable && len(columns) > 1 {
		return fmt.Errorf("non-struct dest type %s with >1 columns (%d)", base.Kind(), len(columns))
	}

	if !scannable {
		var values []interface{}
		var m *reflectx.Mapper

		switch rows.(type) {
		case *Rows:
			m = rows.(*Rows).Mapper
		default:
			m = mapper()
		}

		fields := m.TraversalsByName(base, columns)
		// if we are not unsafe and are missing fields, return an error
		if f, err := missingFields(fields); err != nil && !isUnsafe(rows) {
			return fmt.Errorf("missing destination name %s", columns[f])
		}
		values = make([]interface{}, len(columns))

		for rows.Next() {
			// create a new struct type (which returns PtrTo) and indirect it
			vp = reflect.New(base)
			v = reflect.Indirect(vp)

			err = fieldsByTraversal(v, fields, values, true)

			// scan into the struct field pointers and append to our results
			err = rows.Scan(values...)
			if err != nil {
				return err
			}

			if isPtr {
				direct.Set(reflect.Append(direct, vp))
			} else {
				direct.Set(reflect.Append(direct, v))
			}
		}
	} else {
		for rows.Next() {
			vp = reflect.New(base)
			err = rows.Scan(vp.Interface())
			// append
			if isPtr {
				direct.Set(reflect.Append(direct, vp))
			} else {
				direct.Set(reflect.Append(direct, reflect.Indirect(vp)))
			}
		}
	}

	return rows.Err()
}