gtsocial-umbx

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parameter_description.go (1763B)

      1 package pgproto3
      2 
      3 import (
      4 	"bytes"
      5 	"encoding/binary"
      6 	"encoding/json"
      7 
      8 	"github.com/jackc/pgio"
      9 )
     10 
     11 type ParameterDescription struct {
     12 	ParameterOIDs []uint32
     13 }
     14 
     15 // Backend identifies this message as sendable by the PostgreSQL backend.
     16 func (*ParameterDescription) Backend() {}
     17 
     18 // Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message
     19 // type identifier and 4 byte message length.
     20 func (dst *ParameterDescription) Decode(src []byte) error {
     21 	buf := bytes.NewBuffer(src)
     22 
     23 	if buf.Len() < 2 {
     24 		return &invalidMessageFormatErr{messageType: "ParameterDescription"}
     25 	}
     26 
     27 	// Reported parameter count will be incorrect when number of args is greater than uint16
     28 	buf.Next(2)
     29 	// Instead infer parameter count by remaining size of message
     30 	parameterCount := buf.Len() / 4
     31 
     32 	*dst = ParameterDescription{ParameterOIDs: make([]uint32, parameterCount)}
     33 
     34 	for i := 0; i < parameterCount; i++ {
     35 		dst.ParameterOIDs[i] = binary.BigEndian.Uint32(buf.Next(4))
     36 	}
     37 
     38 	return nil
     39 }
     40 
     41 // Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
     42 func (src *ParameterDescription) Encode(dst []byte) []byte {
     43 	dst = append(dst, 't')
     44 	sp := len(dst)
     45 	dst = pgio.AppendInt32(dst, -1)
     46 
     47 	dst = pgio.AppendUint16(dst, uint16(len(src.ParameterOIDs)))
     48 	for _, oid := range src.ParameterOIDs {
     49 		dst = pgio.AppendUint32(dst, oid)
     50 	}
     51 
     52 	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
     53 
     54 	return dst
     55 }
     56 
     57 // MarshalJSON implements encoding/json.Marshaler.
     58 func (src ParameterDescription) MarshalJSON() ([]byte, error) {
     59 	return json.Marshal(struct {
     60 		Type          string
     61 		ParameterOIDs []uint32
     62 	}{
     63 		Type:          "ParameterDescription",
     64 		ParameterOIDs: src.ParameterOIDs,
     65 	})
     66 }