143 lines
3.1 KiB
Go
143 lines
3.1 KiB
Go
package pgproto3
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import (
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"encoding/binary"
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"encoding/hex"
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"encoding/json"
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"github.com/jackc/pgio"
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)
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type DataRow struct {
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Values [][]byte
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}
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// Backend identifies this message as sendable by the PostgreSQL backend.
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func (*DataRow) 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 *DataRow) Decode(src []byte) error {
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if len(src) < 2 {
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return &invalidMessageFormatErr{messageType: "DataRow"}
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}
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rp := 0
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fieldCount := int(binary.BigEndian.Uint16(src[rp:]))
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rp += 2
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// If the capacity of the values slice is too small OR substantially too
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// large reallocate. This is too avoid one row with many columns from
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// permanently allocating memory.
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if cap(dst.Values) < fieldCount || cap(dst.Values)-fieldCount > 32 {
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newCap := 32
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if newCap < fieldCount {
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newCap = fieldCount
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}
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dst.Values = make([][]byte, fieldCount, newCap)
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} else {
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dst.Values = dst.Values[:fieldCount]
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}
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for i := 0; i < fieldCount; i++ {
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if len(src[rp:]) < 4 {
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return &invalidMessageFormatErr{messageType: "DataRow"}
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}
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msgSize := int(int32(binary.BigEndian.Uint32(src[rp:])))
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rp += 4
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// null
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if msgSize == -1 {
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dst.Values[i] = nil
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} else {
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if len(src[rp:]) < msgSize {
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return &invalidMessageFormatErr{messageType: "DataRow"}
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}
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dst.Values[i] = src[rp : rp+msgSize : rp+msgSize]
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rp += msgSize
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}
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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 *DataRow) Encode(dst []byte) []byte {
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dst = append(dst, 'D')
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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.Values)))
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for _, v := range src.Values {
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if v == nil {
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dst = pgio.AppendInt32(dst, -1)
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continue
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}
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dst = pgio.AppendInt32(dst, int32(len(v)))
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dst = append(dst, v...)
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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 DataRow) MarshalJSON() ([]byte, error) {
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formattedValues := make([]map[string]string, len(src.Values))
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for i, v := range src.Values {
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if v == nil {
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continue
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}
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var hasNonPrintable bool
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for _, b := range v {
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if b < 32 {
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hasNonPrintable = true
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break
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}
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}
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if hasNonPrintable {
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formattedValues[i] = map[string]string{"binary": hex.EncodeToString(v)}
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} else {
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formattedValues[i] = map[string]string{"text": string(v)}
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}
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}
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return json.Marshal(struct {
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Type string
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Values []map[string]string
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}{
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Type: "DataRow",
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Values: formattedValues,
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})
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}
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// UnmarshalJSON implements encoding/json.Unmarshaler.
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func (dst *DataRow) UnmarshalJSON(data []byte) error {
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// Ignore null, like in the main JSON package.
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if string(data) == "null" {
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return nil
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}
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var msg struct {
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Values []map[string]string
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}
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if err := json.Unmarshal(data, &msg); err != nil {
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return err
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}
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dst.Values = make([][]byte, len(msg.Values))
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for n, parameter := range msg.Values {
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var err error
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dst.Values[n], err = getValueFromJSON(parameter)
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if err != nil {
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return err
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}
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}
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return nil
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}
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