github.com/neatlab/neatio@v1.7.3-0.20220425043230-d903e92fcc75/network/p2p/message.go

package p2p

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"sync/atomic"
	"time"

	"github.com/neatlab/neatio/network/p2p/discover"
	"github.com/neatlab/neatio/utilities/event"
	"github.com/neatlab/neatio/utilities/rlp"
)

type Msg struct {
	Code       uint64
	Size       uint32
	Payload    io.Reader
	ReceivedAt time.Time
}

func (msg Msg) Decode(val interface{}) error {
	s := rlp.NewStream(msg.Payload, uint64(msg.Size))
	if err := s.Decode(val); err != nil {
		return newPeerError(errInvalidMsg, "(code %x) (size %d) %v", msg.Code, msg.Size, err)
	}
	return nil
}

func (msg Msg) String() string {
	return fmt.Sprintf("msg #%v (%v bytes)", msg.Code, msg.Size)
}

func (msg Msg) Discard() error {
	_, err := io.Copy(ioutil.Discard, msg.Payload)
	return err
}

type MsgReader interface {
	ReadMsg() (Msg, error)
}

type MsgWriter interface {
	WriteMsg(Msg) error
}

type MsgReadWriter interface {
	MsgReader
	MsgWriter
}

func Send(w MsgWriter, msgcode uint64, data interface{}) error {
	size, r, err := rlp.EncodeToReader(data)
	if err != nil {
		return err
	}
	return w.WriteMsg(Msg{Code: msgcode, Size: uint32(size), Payload: r})
}

func SendItems(w MsgWriter, msgcode uint64, elems ...interface{}) error {
	return Send(w, msgcode, elems)
}

type eofSignal struct {
	wrapped io.Reader
	count   uint32
	eof     chan<- struct{}
}

func (r *eofSignal) Read(buf []byte) (int, error) {
	if r.count == 0 {
		if r.eof != nil {
			r.eof <- struct{}{}
			r.eof = nil
		}
		return 0, io.EOF
	}

	max := len(buf)
	if int(r.count) < len(buf) {
		max = int(r.count)
	}
	n, err := r.wrapped.Read(buf[:max])
	r.count -= uint32(n)
	if (err != nil || r.count == 0) && r.eof != nil {
		r.eof <- struct{}{}
		r.eof = nil
	}
	return n, err
}

func MsgPipe() (*MsgPipeRW, *MsgPipeRW) {
	var (
		c1, c2  = make(chan Msg), make(chan Msg)
		closing = make(chan struct{})
		closed  = new(int32)
		rw1     = &MsgPipeRW{c1, c2, closing, closed}
		rw2     = &MsgPipeRW{c2, c1, closing, closed}
	)
	return rw1, rw2
}

var ErrPipeClosed = errors.New("p2p: read or write on closed message pipe")

type MsgPipeRW struct {
	w       chan<- Msg
	r       <-chan Msg
	closing chan struct{}
	closed  *int32
}

func (p *MsgPipeRW) WriteMsg(msg Msg) error {
	if atomic.LoadInt32(p.closed) == 0 {
		consumed := make(chan struct{}, 1)
		msg.Payload = &eofSignal{msg.Payload, msg.Size, consumed}
		select {
		case p.w <- msg:
			if msg.Size > 0 {

				select {
				case <-consumed:
				case <-p.closing:
				}
			}
			return nil
		case <-p.closing:
		}
	}
	return ErrPipeClosed
}

func (p *MsgPipeRW) ReadMsg() (Msg, error) {
	if atomic.LoadInt32(p.closed) == 0 {
		select {
		case msg := <-p.r:
			return msg, nil
		case <-p.closing:
		}
	}
	return Msg{}, ErrPipeClosed
}

func (p *MsgPipeRW) Close() error {
	if atomic.AddInt32(p.closed, 1) != 1 {

		atomic.StoreInt32(p.closed, 1)
		return nil
	}
	close(p.closing)
	return nil
}

func ExpectMsg(r MsgReader, code uint64, content interface{}) error {
	msg, err := r.ReadMsg()
	if err != nil {
		return err
	}
	if msg.Code != code {
		return fmt.Errorf("message code mismatch: got %d, expected %d", msg.Code, code)
	}
	if content == nil {
		return msg.Discard()
	} else {
		contentEnc, err := rlp.EncodeToBytes(content)
		if err != nil {
			panic("content encode error: " + err.Error())
		}
		if int(msg.Size) != len(contentEnc) {
			return fmt.Errorf("message size mismatch: got %d, want %d", msg.Size, len(contentEnc))
		}
		actualContent, err := ioutil.ReadAll(msg.Payload)
		if err != nil {
			return err
		}
		if !bytes.Equal(actualContent, contentEnc) {
			return fmt.Errorf("message payload mismatch:\ngot:  %x\nwant: %x", actualContent, contentEnc)
		}
	}
	return nil
}

type msgEventer struct {
	MsgReadWriter

	feed     *event.Feed
	peerID   discover.NodeID
	Protocol string
}

func newMsgEventer(rw MsgReadWriter, feed *event.Feed, peerID discover.NodeID, proto string) *msgEventer {
	return &msgEventer{
		MsgReadWriter: rw,
		feed:          feed,
		peerID:        peerID,
		Protocol:      proto,
	}
}

func (self *msgEventer) ReadMsg() (Msg, error) {
	msg, err := self.MsgReadWriter.ReadMsg()
	if err != nil {
		return msg, err
	}
	self.feed.Send(&PeerEvent{
		Type:     PeerEventTypeMsgRecv,
		Peer:     self.peerID,
		Protocol: self.Protocol,
		MsgCode:  &msg.Code,
		MsgSize:  &msg.Size,
	})
	return msg, nil
}

func (self *msgEventer) WriteMsg(msg Msg) error {
	err := self.MsgReadWriter.WriteMsg(msg)
	if err != nil {
		return err
	}
	self.feed.Send(&PeerEvent{
		Type:     PeerEventTypeMsgSend,
		Peer:     self.peerID,
		Protocol: self.Protocol,
		MsgCode:  &msg.Code,
		MsgSize:  &msg.Size,
	})
	return nil
}

func (self *msgEventer) Close() error {
	if v, ok := self.MsgReadWriter.(io.Closer); ok {
		return v.Close()
	}
	return nil
}