82 lines
1.8 KiB
Go
82 lines
1.8 KiB
Go
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package column
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import (
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"fmt"
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"reflect"
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"time"
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"github.com/kshvakov/clickhouse/lib/binary"
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)
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type Nullable struct {
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base
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column Column
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}
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func (null *Nullable) ScanType() reflect.Type {
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return null.column.ScanType()
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}
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func (null *Nullable) Read(decoder *binary.Decoder) (interface{}, error) {
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return null.column.Read(decoder)
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}
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func (null *Nullable) Write(encoder *binary.Encoder, v interface{}) error {
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return nil
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}
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func (null *Nullable) ReadNull(decoder *binary.Decoder, rows int) (_ []interface{}, err error) {
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var (
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isNull byte
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value interface{}
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nulls = make([]byte, rows)
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values = make([]interface{}, rows)
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)
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for i := 0; i < rows; i++ {
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if isNull, err = decoder.ReadByte(); err != nil {
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return nil, err
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}
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nulls[i] = isNull
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}
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for i, isNull := range nulls {
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switch value, err = null.column.Read(decoder); true {
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case err != nil:
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return nil, err
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case isNull == 0:
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values[i] = value
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default:
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values[i] = nil
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}
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}
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return values, nil
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}
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func (null *Nullable) WriteNull(nulls, encoder *binary.Encoder, v interface{}) error {
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if value := reflect.ValueOf(v); v == nil || (value.Kind() == reflect.Ptr && value.IsNil()) {
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if _, err := nulls.Write([]byte{1}); err != nil {
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return err
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}
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return null.column.Write(encoder, null.column.defaultValue())
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}
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if _, err := nulls.Write([]byte{0}); err != nil {
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return err
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}
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return null.column.Write(encoder, v)
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}
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func parseNullable(name, chType string, timezone *time.Location) (*Nullable, error) {
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if len(chType) < 14 {
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return nil, fmt.Errorf("invalid Nullable column type: %s", chType)
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}
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column, err := Factory(name, chType[9:][:len(chType)-10], timezone)
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if err != nil {
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return nil, fmt.Errorf("Nullable(T): %v", err)
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}
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return &Nullable{
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base: base{
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name: name,
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chType: chType,
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},
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column: column,
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}, nil
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}
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