neoneo-go/pkg/wire/payload/mheaders.go
2019-02-25 22:44:14 +00:00

78 lines
1.4 KiB
Go

package payload
import (
"errors"
"io"
"github.com/CityOfZion/neo-go/pkg/wire/command"
"github.com/CityOfZion/neo-go/pkg/wire/util"
)
type HeadersMessage struct {
Headers []*BlockBase
// Padding that is fixed to 0
_ uint8
}
// Users can at most request 2k header
const (
maxHeadersAllowed = 2000
)
var (
ErrMaxHeaders = errors.New("Maximum amount of headers allowed is 2000")
)
func NewHeadersMessage() (*HeadersMessage, error) {
headers := &HeadersMessage{nil, 0}
return headers, nil
}
func (h *HeadersMessage) AddHeader(head *BlockBase) error {
if len(h.Headers)+1 > maxHeadersAllowed {
return ErrMaxHeaders
}
h.Headers = append(h.Headers, head)
return nil
}
// Implements Messager interface
func (v *HeadersMessage) DecodePayload(r io.Reader) error {
br := &util.BinReader{R: r}
lenHeaders := br.VarUint()
v.Headers = make([]*BlockBase, lenHeaders)
for i := 0; i < int(lenHeaders); i++ {
header := &BlockBase{}
header.DecodePayload(br)
var padding uint8
br.Read(&padding)
if padding != 0 {
return ErrPadding
}
v.Headers[i] = header
}
return br.Err
}
// Implements messager interface
func (v *HeadersMessage) EncodePayload(w io.Writer) error {
bw := &util.BinWriter{W: w}
bw.VarUint(uint64(len(v.Headers)))
for _, header := range v.Headers {
header.EncodePayload(bw)
bw.Write(uint8(0))
}
return bw.Err
}
// Implements messager interface
func (v *HeadersMessage) Command() command.Type {
return command.Headers
}