mirror of https://github.com/jackc/pgx.git
126 lines
2.6 KiB
Go
126 lines
2.6 KiB
Go
package pgproto3
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import (
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"encoding/binary"
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"io"
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"github.com/jackc/pgx/chunkreader"
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"github.com/pkg/errors"
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)
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type Frontend struct {
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cr *chunkreader.ChunkReader
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w io.Writer
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// Backend message flyweights
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authentication Authentication
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backendKeyData BackendKeyData
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bindComplete BindComplete
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closeComplete CloseComplete
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commandComplete CommandComplete
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copyBothResponse CopyBothResponse
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copyData CopyData
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copyInResponse CopyInResponse
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copyOutResponse CopyOutResponse
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copyDone CopyDone
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dataRow DataRow
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emptyQueryResponse EmptyQueryResponse
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errorResponse ErrorResponse
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functionCallResponse FunctionCallResponse
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noData NoData
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noticeResponse NoticeResponse
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notificationResponse NotificationResponse
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parameterDescription ParameterDescription
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parameterStatus ParameterStatus
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parseComplete ParseComplete
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readyForQuery ReadyForQuery
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rowDescription RowDescription
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bodyLen int
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msgType byte
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partialMsg bool
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}
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func NewFrontend(r io.Reader, w io.Writer) (*Frontend, error) {
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cr := chunkreader.NewChunkReader(r)
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return &Frontend{cr: cr, w: w}, nil
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}
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func (b *Frontend) Send(msg FrontendMessage) error {
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_, err := b.w.Write(msg.Encode(nil))
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return err
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}
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func (b *Frontend) Receive() (BackendMessage, error) {
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if !b.partialMsg {
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header, err := b.cr.Next(5)
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if err != nil {
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return nil, err
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}
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b.msgType = header[0]
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b.bodyLen = int(binary.BigEndian.Uint32(header[1:])) - 4
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b.partialMsg = true
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}
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var msg BackendMessage
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switch b.msgType {
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case '1':
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msg = &b.parseComplete
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case '2':
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msg = &b.bindComplete
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case '3':
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msg = &b.closeComplete
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case 'A':
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msg = &b.notificationResponse
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case 'c':
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msg = &b.copyDone
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case 'C':
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msg = &b.commandComplete
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case 'd':
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msg = &b.copyData
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case 'D':
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msg = &b.dataRow
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case 'E':
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msg = &b.errorResponse
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case 'G':
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msg = &b.copyInResponse
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case 'H':
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msg = &b.copyOutResponse
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case 'I':
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msg = &b.emptyQueryResponse
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case 'K':
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msg = &b.backendKeyData
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case 'n':
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msg = &b.noData
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case 'N':
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msg = &b.noticeResponse
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case 'R':
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msg = &b.authentication
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case 'S':
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msg = &b.parameterStatus
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case 't':
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msg = &b.parameterDescription
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case 'T':
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msg = &b.rowDescription
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case 'V':
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msg = &b.functionCallResponse
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case 'W':
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msg = &b.copyBothResponse
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case 'Z':
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msg = &b.readyForQuery
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default:
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return nil, errors.Errorf("unknown message type: %c", b.msgType)
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}
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msgBody, err := b.cr.Next(b.bodyLen)
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if err != nil {
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return nil, err
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}
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b.partialMsg = false
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err = msg.Decode(msgBody)
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return msg, err
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}
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