68 lines
1.8 KiB
Go
68 lines
1.8 KiB
Go
package pgproto3
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import (
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"bytes"
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"encoding/binary"
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"encoding/json"
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"errors"
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"math"
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"github.com/jackc/pgx/v5/internal/pgio"
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)
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type ParameterDescription struct {
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ParameterOIDs []uint32
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}
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// Backend identifies this message as sendable by the PostgreSQL backend.
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func (*ParameterDescription) Backend() {}
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// Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message
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// type identifier and 4 byte message length.
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func (dst *ParameterDescription) Decode(src []byte) error {
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buf := bytes.NewBuffer(src)
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if buf.Len() < 2 {
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return &invalidMessageFormatErr{messageType: "ParameterDescription"}
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}
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// Reported parameter count will be incorrect when number of args is greater than uint16
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buf.Next(2)
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// Instead infer parameter count by remaining size of message
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parameterCount := buf.Len() / 4
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*dst = ParameterDescription{ParameterOIDs: make([]uint32, parameterCount)}
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for i := 0; i < parameterCount; i++ {
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dst.ParameterOIDs[i] = binary.BigEndian.Uint32(buf.Next(4))
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}
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return nil
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}
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// Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
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func (src *ParameterDescription) Encode(dst []byte) ([]byte, error) {
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dst, sp := beginMessage(dst, 't')
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if len(src.ParameterOIDs) > math.MaxUint16 {
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return nil, errors.New("too many parameter oids")
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}
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dst = pgio.AppendUint16(dst, uint16(len(src.ParameterOIDs)))
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for _, oid := range src.ParameterOIDs {
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dst = pgio.AppendUint32(dst, oid)
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}
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return finishMessage(dst, sp)
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}
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// MarshalJSON implements encoding/json.Marshaler.
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func (src ParameterDescription) MarshalJSON() ([]byte, error) {
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return json.Marshal(struct {
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Type string
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ParameterOIDs []uint32
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}{
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Type: "ParameterDescription",
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ParameterOIDs: src.ParameterOIDs,
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})
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}
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