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114 lines
2.8 KiB
Go
114 lines
2.8 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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"github.com/jackc/pgio"
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)
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const (
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TextFormat = 0
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BinaryFormat = 1
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)
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type FieldDescription struct {
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Name []byte
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TableOID uint32
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TableAttributeNumber uint16
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DataTypeOID uint32
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DataTypeSize int16
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TypeModifier int32
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Format int16
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}
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type RowDescription struct {
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Fields []FieldDescription
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}
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// Backend identifies this message as sendable by the PostgreSQL backend.
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func (*RowDescription) 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 *RowDescription) Decode(src []byte) error {
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if len(src) < 2 {
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return &invalidMessageFormatErr{messageType: "RowDescription"}
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}
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fieldCount := int(binary.BigEndian.Uint16(src))
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rp := 2
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dst.Fields = dst.Fields[0:0]
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for i := 0; i < fieldCount; i++ {
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var fd FieldDescription
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idx := bytes.IndexByte(src[rp:], 0)
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if idx < 0 {
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return &invalidMessageFormatErr{messageType: "RowDescription"}
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}
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fd.Name = src[rp : rp+idx]
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rp += idx + 1
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// Since buf.Next() doesn't return an error if we hit the end of the buffer
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// check Len ahead of time
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if len(src[rp:]) < 18 {
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return &invalidMessageFormatErr{messageType: "RowDescription"}
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}
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fd.TableOID = binary.BigEndian.Uint32(src[rp:])
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rp += 4
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fd.TableAttributeNumber = binary.BigEndian.Uint16(src[rp:])
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rp += 2
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fd.DataTypeOID = binary.BigEndian.Uint32(src[rp:])
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rp += 4
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fd.DataTypeSize = int16(binary.BigEndian.Uint16(src[rp:]))
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rp += 2
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fd.TypeModifier = int32(binary.BigEndian.Uint32(src[rp:]))
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rp += 4
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fd.Format = int16(binary.BigEndian.Uint16(src[rp:]))
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rp += 2
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dst.Fields = append(dst.Fields, fd)
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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 *RowDescription) Encode(dst []byte) []byte {
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dst = append(dst, 'T')
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sp := len(dst)
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dst = pgio.AppendInt32(dst, -1)
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dst = pgio.AppendUint16(dst, uint16(len(src.Fields)))
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for _, fd := range src.Fields {
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dst = append(dst, fd.Name...)
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dst = append(dst, 0)
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dst = pgio.AppendUint32(dst, fd.TableOID)
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dst = pgio.AppendUint16(dst, fd.TableAttributeNumber)
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dst = pgio.AppendUint32(dst, fd.DataTypeOID)
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dst = pgio.AppendInt16(dst, fd.DataTypeSize)
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dst = pgio.AppendInt32(dst, fd.TypeModifier)
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dst = pgio.AppendInt16(dst, fd.Format)
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}
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pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
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return dst
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}
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// MarshalJSON implements encoding/json.Marshaler.
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func (src RowDescription) MarshalJSON() ([]byte, error) {
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return json.Marshal(struct {
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Type string
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Fields []FieldDescription
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}{
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Type: "RowDescription",
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Fields: src.Fields,
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})
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}
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