Merge branch 'main' into tweaks-suggestions

swarmsim/codex/dhttracker.nim

@@ -13,13 +13,13 @@ type
   PeerDescriptor* = ref object of RootObj
     peerId*: int
     lastSeen*: uint64
-    expirationTimer: AwaitableHandle
+    peerExpiration: ScheduledEvent
 
 type ArrayShuffler = proc (arr: var seq[PeerDescriptor]): void
 
 type
   DHTTracker* = ref object of Protocol
-    expirationTimer*: Duration
+    peerExpiration*: Duration
     maxPeers*: uint
     peers: OrderedTable[int, PeerDescriptor]
     shuffler: ArrayShuffler
@@ -45,11 +45,11 @@ proc new*(
   T: type DHTTracker,
   maxPeers: uint,
   shuffler: ArrayShuffler = RandomShuffler,
-  expirationTimer: Duration = DHTTracker.defaultExpiry,
+  peerExpiration: Duration = DHTTracker.defaultExpiry,
 ): DHTTracker =
   DHTTracker(
     # This should in general be safe as those are always positive.
-    expirationTimer: expirationTimer,
+    peerExpiration: peerExpiration,
     maxPeers: maxPeers,
     shuffler: shuffler,
     peers: initOrderedTable[int, PeerDescriptor](),
@@ -59,17 +59,17 @@ proc new*(
 proc peers*(self: DHTTracker): seq[PeerDescriptor] = self.peers.values.toSeq()
 
 proc cancelExpiryTimer(self: DHTTracker, peerId: int) =
-  self.peers[peerId].expirationTimer.schedulable.cancel()
+  self.peers[peerId].peerExpiration.schedulable.cancel()
 
 proc createExpiryTimer(self: DHTTracker, peerId: int,
-    engine: EventDrivenEngine): AwaitableHandle =
+    engine: EventDrivenEngine): ScheduledEvent =
-  let expirationTimer = ExpirationTimer(
+  let peerExpiration = ExpirationTimer(
     peerId: peerId,
     tracker: self,
-    time: engine.currentTime + uint64(self.expirationTimer.inSeconds())
+    time: engine.currentTime + uint64(self.peerExpiration.inSeconds())
   )
 
-  engine.awaitableSchedule(expirationTimer)
+  engine.awaitableSchedule(peerExpiration)
 
 proc oldestInsertion(self: DHTTracker): int =
   # We maintain the invariant that the first element to have been inserted
@@ -78,23 +78,26 @@ proc oldestInsertion(self: DHTTracker): int =
   for peerId in self.peers.keys:
     return peerId
 
+proc removePeer(self: DHTTracker, peerId: int) =
+  self.cancelExpiryTimer(peerId)
+  self.peers.del(peerId)
+
 proc addPeer(self: DHTTracker, message: PeerAnnouncement,
     engine: EventDrivenEngine) =
 
   let peerId = message.peerId
 
   if peerId in self.peers:
-    self.cancelExpiryTimer(peerId)
+    # Makes sure that the most recently seen peer is always inserted last.
+    self.removePeer(peerId)
 
   elif uint(len(self.peers)) == self.maxPeers:
-    let oldest = self.oldestInsertion()
+    self.removePeer(self.oldestInsertion())
-    self.cancelExpiryTimer(oldest)
-    self.peers.del(oldest)
 
   self.peers[peerId] = PeerDescriptor(
     peerId: message.peerId,
     lastSeen: engine.currentTime,
-    expirationTimer: self.createExpiryTimer(peerId, engine)
+    peerExpiration: self.createExpiryTimer(peerId, engine)
   )
 
 method atScheduledTime*(self: ExpirationTimer, engine: EventDrivenEngine): void =

swarmsim/engine/eventdrivenengine.nim

@@ -10,7 +10,7 @@ export times
 export EventDrivenEngine
 
 type
-  AwaitableHandle* = object of RootObj
+  ScheduledEvent* = object of RootObj
     schedulable*: SchedulableEvent
     engine: EventDrivenEngine
 
@@ -24,9 +24,9 @@ proc schedule*(self: EventDrivenEngine, schedulable: SchedulableEvent): void =
   self.queue.push(schedulable)
 
 proc awaitableSchedule*(self: EventDrivenEngine,
-    schedulable: SchedulableEvent): AwaitableHandle =
+    schedulable: SchedulableEvent): ScheduledEvent =
   self.schedule(schedulable)
-  AwaitableHandle(schedulable: schedulable, engine: self)
+  ScheduledEvent(schedulable: schedulable, engine: self)
 
 proc scheduleAll*[T: SchedulableEvent](self: EventDrivenEngine,
     schedulables: seq[T]): void =
@@ -65,5 +65,5 @@ proc runUntil*(self: EventDrivenEngine, until: Duration): void =
 proc run*(self: EventDrivenEngine): void =
   self.runUntil(high(uint64))
 
-proc doAwait*(self: AwaitableHandle): void =
+proc doAwait*(self: ScheduledEvent): void =
   self.engine.runUntil(self.schedulable.time)

swarmsim/engine/network.nim

@@ -12,7 +12,7 @@ export eventdrivenengine
 export types
 
 type
-  ScheduledMessage = ref object of SchedulableEvent
+  MessageSend = ref object of SchedulableEvent
     network: Network
     message: Message
 
@@ -36,17 +36,17 @@ proc remove*(self: Network, peer: Peer) =
   self.peers.excl(peer)
 
 proc send*(self: Network, message: Message,
-  linkDelay: Option[uint64] = none(uint64)): AwaitableHandle =
+  linkDelay: Option[uint64] = none(uint64)): ScheduledEvent =
 
   let delay = linkDelay.get(self.defaultLinkDelay)
 
   self.engine.awaitableSchedule(
-    ScheduledMessage(
+    MessageSend(
       time: self.engine.currentTime + delay,
       message: message,
       network: self
     )
   )
 
-method atScheduledTime*(self: ScheduledMessage, engine: EventDrivenEngine) =
+method atScheduledTime*(self: MessageSend, engine: EventDrivenEngine) =
   self.message.receiver.deliver(self.message, engine, self.network)

tests/codex/tdhttracker.nim

@@ -78,7 +78,7 @@ suite "tracker node":
     engine.runUntil(2*DHTTracker.defaultExpiry + 1.dseconds)
     check(len(getPeerArray(trackerPeer)) == 0)
 
-  test "should drop oldest peers when table is full":
+  test "should drop least recently seen peer when table is full":
     announcePeer(network, trackerPeer, 25, delay = 0)
     announcePeer(network, trackerPeer, 35, delay = 1)
     announcePeer(network, trackerPeer, 45, delay = 2)
@@ -87,6 +87,7 @@ suite "tracker node":
 
     check(getPeerIdArray(trackerPeer).sorted == @[25, 35, 45, 55, 65])
 
+    announcePeer(network, trackerPeer, 25, delay = 1)
     announcePeer(network, trackerPeer, 75, delay = 1)
 
-    check(getPeerIdArray(trackerPeer).sorted == @[35, 45, 55, 65, 75])
+    check(getPeerIdArray(trackerPeer).sorted == @[25, 45, 55, 65, 75])