path: root/core/test/fake-transport.go

// Copyright 2018 The dexon-consensus Authors
// This file is part of the dexon-consensus library.
//
// The dexon-consensus library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus library. If not, see
// <http://www.gnu.org/licenses/>.

package test

import (
    "fmt"
    "time"

    "github.com/dexon-foundation/dexon-consensus/core/crypto"
    "github.com/dexon-foundation/dexon-consensus/core/types"
)

type fakePeerRecord struct {
    sendChannel chan<- *TransportEnvelope
    pubKey      crypto.PublicKey
}

type fakeHandshake struct {
    dMoment time.Time
    peers   map[types.NodeID]fakePeerRecord
}

// FakeTransport implement TransportServer and TransportClient interface
// by using golang channel.
type FakeTransport struct {
    peerType      TransportPeerType
    nID           types.NodeID
    pubKey        crypto.PublicKey
    recvChannel   chan *TransportEnvelope
    serverChannel chan<- *TransportEnvelope
    peers         map[types.NodeID]fakePeerRecord
    dMoment       time.Time
}

// NewFakeTransportServer constructs FakeTransport instance for peer server.
func NewFakeTransportServer() TransportServer {
    return &FakeTransport{
        peerType:    TransportPeerServer,
        recvChannel: make(chan *TransportEnvelope, 1000),
    }
}

// NewFakeTransportClient constructs FakeTransport instance for peer.
func NewFakeTransportClient(pubKey crypto.PublicKey) TransportClient {
    return &FakeTransport{
        peerType:    TransportPeer,
        recvChannel: make(chan *TransportEnvelope, 1000),
        nID:         types.NewNodeID(pubKey),
        pubKey:      pubKey,
    }
}

// Send implements Transport.Send method.
func (t *FakeTransport) Send(
    endpoint types.NodeID, msg interface{}) (err error) {
    rec, exists := t.peers[endpoint]
    if !exists {
        err = fmt.Errorf("the endpoint does not exists: %v", endpoint)
        return
    }
    go func(ch chan<- *TransportEnvelope) {
        ch <- &TransportEnvelope{
            PeerType: t.peerType,
            From:     t.nID,
            Msg:      msg,
        }
    }(rec.sendChannel)
    return
}

// Report implements Transport.Report method.
func (t *FakeTransport) Report(msg interface{}) (err error) {
    go func() {
        t.serverChannel <- &TransportEnvelope{
            PeerType: TransportPeer,
            From:     t.nID,
            Msg:      msg,
        }
    }()
    return
}

// Broadcast implements Transport.Broadcast method.
func (t *FakeTransport) Broadcast(endpoints map[types.NodeID]struct{},
    latency LatencyModel, msg interface{}) (err error) {
    for ID := range endpoints {
        if ID == t.nID {
            continue
        }
        go func(nID types.NodeID) {
            time.Sleep(latency.Delay())
            t.Send(nID, msg)
        }(ID)
    }
    return
}

// Close implements Transport.Close method.
func (t *FakeTransport) Close() (err error) {
    close(t.recvChannel)
    return
}

// Peers implements Transport.Peers method.
func (t *FakeTransport) Peers() (peers []crypto.PublicKey) {
    for _, rec := range t.peers {
        peers = append(peers, rec.pubKey)
    }
    return
}

// Join implements TransportClient.Join method.
func (t *FakeTransport) Join(
    serverEndpoint interface{}) (<-chan *TransportEnvelope, error) {

    var (
        envelopes = []*TransportEnvelope{}
        ok        bool
    )
    if t.serverChannel, ok = serverEndpoint.(chan *TransportEnvelope); !ok {
        return nil, fmt.Errorf("accept channel of *TransportEnvelope when join")
    }
    t.Report(t)
    // Wait for peers info.
    for {
        envelope := <-t.recvChannel
        if envelope.PeerType != TransportPeerServer {
            envelopes = append(envelopes, envelope)
            continue
        }
        if handShake, ok := envelope.Msg.(fakeHandshake); ok {
            t.dMoment = handShake.dMoment
            t.peers = handShake.peers
        } else {
            envelopes = append(envelopes, envelope)
            continue
        }
        for _, envelope := range envelopes {
            t.recvChannel <- envelope
        }
        break
    }
    return t.recvChannel, nil
}

// DMoment implments TrnansportClient.DMoment method.
func (t *FakeTransport) DMoment() time.Time {
    return t.dMoment
}

// Host implements TransportServer.Host method.
func (t *FakeTransport) Host() (chan *TransportEnvelope, error) {
    return t.recvChannel, nil
}

// SetDMoment implements TransportServer.SetDMoment method.
func (t *FakeTransport) SetDMoment(dMoment time.Time) {
    t.dMoment = dMoment
}

// WaitForPeers implements TransportServer.WaitForPeers method.
func (t *FakeTransport) WaitForPeers(numPeers uint32) (err error) {
    t.peers = make(map[types.NodeID]fakePeerRecord)
    for {
        envelope := <-t.recvChannel
        // Panic here if some peer send other stuffs before
        // receiving peer lists.
        newPeer := envelope.Msg.(*FakeTransport)
        t.peers[envelope.From] = fakePeerRecord{
            sendChannel: newPeer.recvChannel,
            pubKey:      newPeer.pubKey,
        }
        if uint32(len(t.peers)) == numPeers {
            break
        }
    }
    // The collected peer channels are shared for all peers.
    peers := make(map[types.NodeID]struct{})
    for ID := range t.peers {
        peers[ID] = struct{}{}
    }
    handShake := fakeHandshake{
        dMoment: t.dMoment,
        peers:   t.peers,
    }
    if err = t.Broadcast(peers, &FixedLatencyModel{}, handShake); err != nil {
        return
    }
    return
}