84 lines
2.0 KiB
Go
84 lines
2.0 KiB
Go
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package packets
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import (
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"bytes"
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"fmt"
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"io"
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"github.com/winc-link/hummingbird/internal/pkg/codes"
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)
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// Disconnect represents the MQTT Disconnect packet
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type Disconnect struct {
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Version Version
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FixHeader *FixHeader
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// V5
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Code codes.Code
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Properties *Properties
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}
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func (d *Disconnect) String() string {
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return fmt.Sprintf("Disconnect, Version: %v, Code: %v, Properties: %s", d.Version, d.Code, d.Properties)
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}
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// Pack encodes the packet struct into bytes and writes it into io.Writer.
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func (d *Disconnect) Pack(w io.Writer) error {
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var err error
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d.FixHeader = &FixHeader{PacketType: DISCONNECT, Flags: FlagReserved}
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if IsVersion3X(d.Version) {
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d.FixHeader.RemainLength = 0
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return d.FixHeader.Pack(w)
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}
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bufw := &bytes.Buffer{}
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if d.Code != codes.Success || d.Properties != nil {
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bufw.WriteByte(d.Code)
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d.Properties.Pack(bufw, DISCONNECT)
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}
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d.FixHeader.RemainLength = bufw.Len()
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err = d.FixHeader.Pack(w)
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if err != nil {
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return err
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}
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_, err = bufw.WriteTo(w)
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return err
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}
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// Unpack read the packet bytes from io.Reader and decodes it into the packet struct.
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func (d *Disconnect) Unpack(r io.Reader) error {
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restBuffer := make([]byte, d.FixHeader.RemainLength)
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_, err := io.ReadFull(r, restBuffer)
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if err != nil {
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return codes.ErrMalformed
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}
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if d.Version == Version5 {
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d.Properties = &Properties{}
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bufr := bytes.NewBuffer(restBuffer)
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if d.FixHeader.RemainLength == 0 {
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d.Code = codes.Success
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return nil
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}
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d.Code, err = bufr.ReadByte()
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if err != nil {
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return codes.ErrMalformed
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}
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if !ValidateCode(DISCONNECT, d.Code) {
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return codes.ErrProtocol
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}
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return d.Properties.Unpack(bufr, DISCONNECT)
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}
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return nil
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}
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// NewDisConnectPackets returns a Disconnect instance by the given FixHeader and io.Reader
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func NewDisConnectPackets(fh *FixHeader, version Version, r io.Reader) (*Disconnect, error) {
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if fh.Flags != 0 {
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return nil, codes.ErrMalformed
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}
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p := &Disconnect{FixHeader: fh, Version: version}
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err := p.Unpack(r)
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if err != nil {
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return nil, err
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}
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return p, nil
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}
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