78 lines
2.2 KiB
Go
78 lines
2.2 KiB
Go
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package raft
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import (
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"encoding/binary"
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"io"
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)
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const requestVoteRequestHeaderSize = 4 + 8 + 8 + 8 + 4
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// The request sent to a server to vote for a candidate to become a leader.
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type RequestVoteRequest struct {
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peer *Peer
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Term uint64
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LastLogIndex uint64
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LastLogTerm uint64
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CandidateName string
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}
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// Creates a new RequestVote request.
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func newRequestVoteRequest(term uint64, candidateName string, lastLogIndex uint64, lastLogTerm uint64) *RequestVoteRequest {
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return &RequestVoteRequest{
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Term: term,
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LastLogIndex: lastLogIndex,
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LastLogTerm: lastLogTerm,
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CandidateName: candidateName,
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}
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}
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func (req *RequestVoteRequest) encode(w io.Writer) (int, error) {
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candidateNameSize := len(req.CandidateName)
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b := make([]byte, requestVoteRequestHeaderSize + candidateNameSize)
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// Write request.
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binary.BigEndian.PutUint32(b[0:4], protocolVersion)
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binary.BigEndian.PutUint64(b[4:12], req.Term)
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binary.BigEndian.PutUint64(b[12:20], req.LastLogIndex)
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binary.BigEndian.PutUint64(b[20:28], req.LastLogTerm)
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binary.BigEndian.PutUint32(b[28:32], uint32(candidateNameSize))
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copy(b[32:], []byte(req.CandidateName))
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return w.Write(b)
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}
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func (req *RequestVoteRequest) decode(r io.Reader) (int, error) {
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var eof error
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header := make([]byte, requestVoteRequestHeaderSize)
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if n, err := r.Read(header); err == io.EOF {
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return n, io.ErrUnexpectedEOF
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} else if err != nil {
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return n, err
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}
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// Read candidate name.
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candidateName := make([]byte, binary.BigEndian.Uint32(header[28:32]))
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if n, err := r.Read(candidateName); err == io.EOF {
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if err == io.EOF && n != len(candidateName) {
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return requestVoteRequestHeaderSize+n, io.ErrUnexpectedEOF
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} else {
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eof = io.EOF
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}
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} else if err != nil {
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return requestVoteRequestHeaderSize+n, err
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}
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totalBytes := requestVoteRequestHeaderSize + len(candidateName)
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// Verify that the encoding format can be read.
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if version := binary.BigEndian.Uint32(header[0:4]); version != protocolVersion {
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return totalBytes, errUnsupportedLogVersion
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}
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req.Term = binary.BigEndian.Uint64(header[4:12])
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req.LastLogIndex = binary.BigEndian.Uint64(header[12:20])
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req.LastLogTerm = binary.BigEndian.Uint64(header[20:28])
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req.CandidateName = string(candidateName)
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return totalBytes, eof
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}
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