82 lines
1.7 KiB
Go
82 lines
1.7 KiB
Go
package payload
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import (
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"errors"
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"io"
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"github.com/CityOfZion/neo-go/pkg/wire/command"
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"github.com/CityOfZion/neo-go/pkg/wire/util"
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)
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// HeadersMessage represents a Header(s) Message on the neo-network
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type HeadersMessage struct {
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Headers []*BlockBase
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// Padding that is fixed to 0
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_ uint8
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}
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// Users can at most request 2k header
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const (
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maxHeadersAllowed = 2000
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)
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var (
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errMaxHeaders = errors.New("Maximum amount of headers allowed is 2000")
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)
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//NewHeadersMessage returns a HeadersMessage Object
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func NewHeadersMessage() (*HeadersMessage, error) {
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headers := &HeadersMessage{nil, 0}
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return headers, nil
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}
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// AddHeader adds a header into the list of Headers.
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// Since a header is just blockbase with padding, we use BlockBase
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func (h *HeadersMessage) AddHeader(head *BlockBase) error {
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if len(h.Headers)+1 > maxHeadersAllowed {
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return errMaxHeaders
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}
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h.Headers = append(h.Headers, head)
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return nil
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}
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// DecodePayload Implements Messager interface
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func (h *HeadersMessage) DecodePayload(r io.Reader) error {
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br := &util.BinReader{R: r}
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lenHeaders := br.VarUint()
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h.Headers = make([]*BlockBase, lenHeaders)
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for i := 0; i < int(lenHeaders); i++ {
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header := &BlockBase{}
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header.DecodePayload(br)
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var padding uint8
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br.Read(&padding)
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if padding != 0 {
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return errPadding
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}
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h.Headers[i] = header
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}
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return br.Err
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}
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// EncodePayload Implements messager interface
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func (h *HeadersMessage) EncodePayload(w io.Writer) error {
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bw := &util.BinWriter{W: w}
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bw.VarUint(uint64(len(h.Headers)))
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for _, header := range h.Headers {
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header.EncodePayload(bw)
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bw.Write(uint8(0))
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}
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return bw.Err
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}
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// Command Implements messager interface
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func (h *HeadersMessage) Command() command.Type {
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return command.Headers
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}
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