bitswap virtual test net code should send messages in order

License: MIT
Signed-off-by: Jeromy <jeromyj@gmail.com>

exchange/bitswap/testnet/virtual.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"sync"
+	"time"
 
 	bsmsg "github.com/ipfs/go-ipfs/exchange/bitswap/message"
 	bsnet "github.com/ipfs/go-ipfs/exchange/bitswap/network"
@@ -22,7 +23,7 @@ var log = logging.Logger("bstestnet")
 
 func VirtualNetwork(rs mockrouting.Server, d delay.D) Network {
 	return &network{
-		clients:       make(map[peer.ID]bsnet.Receiver),
+		clients:       make(map[peer.ID]*receiverQueue),
 		delay:         d,
 		routingserver: rs,
 		conns:         make(map[string]struct{}),
@@ -31,12 +32,28 @@ func VirtualNetwork(rs mockrouting.Server, d delay.D) Network {
 
 type network struct {
 	mu            sync.Mutex
-	clients       map[peer.ID]bsnet.Receiver
+	clients       map[peer.ID]*receiverQueue
 	routingserver mockrouting.Server
 	delay         delay.D
 	conns         map[string]struct{}
 }
 
+type message struct {
+	from       peer.ID
+	msg        bsmsg.BitSwapMessage
+	shouldSend time.Time
+}
+
+// receiverQueue queues up a set of messages to be sent, and sends them *in
+// order* with their delays respected as much as sending them in order allows
+// for
+type receiverQueue struct {
+	receiver bsnet.Receiver
+	queue    []*message
+	active   bool
+	lk       sync.Mutex
+}
+
 func (n *network) Adapter(p testutil.Identity) bsnet.BitSwapNetwork {
 	n.mu.Lock()
 	defer n.mu.Unlock()
@@ -46,7 +63,7 @@ func (n *network) Adapter(p testutil.Identity) bsnet.BitSwapNetwork {
 		network: n,
 		routing: n.routingserver.Client(p),
 	}
-	n.clients[p.ID()] = client
+	n.clients[p.ID()] = &receiverQueue{receiver: client}
 	return client
 }
 
@@ -64,7 +81,7 @@ func (n *network) SendMessage(
 	ctx context.Context,
 	from peer.ID,
 	to peer.ID,
-	message bsmsg.BitSwapMessage) error {
+	mes bsmsg.BitSwapMessage) error {
 
 	n.mu.Lock()
 	defer n.mu.Unlock()
@@ -77,7 +94,12 @@ func (n *network) SendMessage(
 	// nb: terminate the context since the context wouldn't actually be passed
 	// over the network in a real scenario
 
-	go n.deliver(receiver, from, message)
+	msg := &message{
+		from:       from,
+		msg:        mes,
+		shouldSend: time.Now().Add(n.delay.Get()),
+	}
+	receiver.enqueue(msg)
 
 	return nil
 }
@@ -191,11 +213,38 @@ func (nc *networkClient) ConnectTo(_ context.Context, p peer.ID) error {
 
 	// TODO: add handling for disconnects
 
-	otherClient.PeerConnected(nc.local)
+	otherClient.receiver.PeerConnected(nc.local)
 	nc.Receiver.PeerConnected(p)
 	return nil
 }
 
+func (rq *receiverQueue) enqueue(m *message) {
+	rq.lk.Lock()
+	defer rq.lk.Unlock()
+	rq.queue = append(rq.queue, m)
+	if !rq.active {
+		rq.active = true
+		go rq.process()
+	}
+}
+
+func (rq *receiverQueue) process() {
+	for {
+		rq.lk.Lock()
+		if len(rq.queue) == 0 {
+			rq.active = false
+			rq.lk.Unlock()
+			return
+		}
+		m := rq.queue[0]
+		rq.queue = rq.queue[1:]
+		rq.lk.Unlock()
+
+		time.Sleep(time.Until(m.shouldSend))
+		rq.receiver.ReceiveMessage(context.TODO(), m.from, m.msg)
+	}
+}
+
 func tagForPeers(a, b peer.ID) string {
 	if a < b {
 		return string(a + b)