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743b98b298
Though this doesn't follow Go naming conventions exactly it makes names more consistent with PostgreSQL and it is easier to read. For example, TIDOID becomes TidOid. In addition this is one less breaking change in the move to V3.
105 lines
2.0 KiB
Go
105 lines
2.0 KiB
Go
package pgtype
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import (
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"encoding/binary"
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"fmt"
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"io"
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"strconv"
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"strings"
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"github.com/jackc/pgx/pgio"
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)
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// Tid is PostgreSQL's Tuple Identifier type.
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//
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// When one does
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//
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// select ctid, * from some_table;
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//
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// it is the data type of the ctid hidden system column.
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//
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// It is currently implemented as a pair unsigned two byte integers.
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// Its conversion functions can be found in src/backend/utils/adt/tid.c
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// in the PostgreSQL sources.
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type Tid struct {
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BlockNumber uint32
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OffsetNumber uint16
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Status Status
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}
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func (dst *Tid) DecodeText(src []byte) error {
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if src == nil {
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*dst = Tid{Status: Null}
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return nil
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}
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if len(src) < 5 {
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return fmt.Errorf("invalid length for tid: %v", len(src))
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}
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parts := strings.SplitN(string(src[1:len(src)-1]), ",", 2)
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if len(parts) < 2 {
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return fmt.Errorf("invalid format for tid")
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}
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blockNumber, err := strconv.ParseUint(parts[0], 10, 32)
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if err != nil {
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return err
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}
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offsetNumber, err := strconv.ParseUint(parts[1], 10, 16)
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if err != nil {
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return err
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}
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*dst = Tid{BlockNumber: uint32(blockNumber), OffsetNumber: uint16(offsetNumber), Status: Present}
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return nil
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}
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func (dst *Tid) DecodeBinary(src []byte) error {
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if src == nil {
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*dst = Tid{Status: Null}
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return nil
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}
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if len(src) != 6 {
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return fmt.Errorf("invalid length for tid: %v", len(src))
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}
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*dst = Tid{
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BlockNumber: binary.BigEndian.Uint32(src),
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OffsetNumber: binary.BigEndian.Uint16(src[4:]),
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Status: Present,
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}
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return nil
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}
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func (src Tid) EncodeText(w io.Writer) (bool, error) {
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switch src.Status {
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case Null:
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return true, nil
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case Undefined:
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return false, errUndefined
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}
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_, err := io.WriteString(w, fmt.Sprintf(`(%d,%d)`, src.BlockNumber, src.OffsetNumber))
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return false, err
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}
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func (src Tid) EncodeBinary(w io.Writer) (bool, error) {
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switch src.Status {
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case Null:
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return true, nil
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case Undefined:
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return false, errUndefined
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}
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_, err := pgio.WriteUint32(w, src.BlockNumber)
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if err != nil {
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return false, err
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}
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_, err = pgio.WriteUint16(w, src.OffsetNumber)
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return false, err
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}
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