.

go/neo/connection.go

@@ -51,28 +51,26 @@ import (
 type NodeLink struct {
 	peerLink net.Conn		// raw conn to peer
 
-	connMu     sync.Mutex	// TODO -> RW ?
+	connMu     sync.Mutex
 	connTab    map[uint32]*Conn	// connId -> Conn associated with connId
 	nextConnId uint32		// next connId to use for Conn initiated by us
 
 	serveWg sync.WaitGroup		// for serve{Send,Recv}
 	acceptq chan *Conn		// queue of incoming connections for Accept
 					// = nil if NodeLink is not accepting connections
-
 	txq	chan txReq		// tx requests from Conns go via here
+					// (rx packets are routed to Conn.rxq)
 
-	errMu    sync.Mutex
-	errRecv	 error			// error got from recvPkt on shutdown
+	down     chan struct{}	// ready when NodeLink is marked as no longer operational
+	downOnce sync.Once	// shutdown may be due both Close and IO error
+	downWg   sync.WaitGroup	// for activities at shutdown
+	errClose error		// error got from peerLink.Close on shutdown
 
-	// once because: NodeLink has to be explicitly closed by user; it can also
-	// be "closed" by IO errors on peerLink
-	closeOnce sync.Once
+	errMu    sync.Mutex
+	errRecv	 error		// error got from recvPkt on shutdown
 
-	down      chan struct{}		// ready when NodeLink is marked as no longer operational
-	closeCalled uint32		// whether Close was called; ^^^ can be from IO error
+	closeCalled uint32	// whether Close was called
 
-	shutdownWg  sync.WaitGroup	// for activities at shutdown
-	errClose error			// error got from peerLink.Close
 
 }
 
@@ -188,16 +186,16 @@ func (nl *NodeLink) NewConn() (*Conn, error) {
 // shutdown closes peerLink and marks NodeLink as no longer operational
 // it also shutdowns and all active Conns.
 func (nl *NodeLink) shutdown() {
-	nl.closeOnce.Do(func() {
+	nl.downOnce.Do(func() {
 		close(nl.down)
 
 		// close actual link to peer. this will wakeup {send,recv}Pkt
 		// NOTE we need it here so that e.g. aborting on error in serveSend wakes up serveRecv
 		nl.errClose = nl.peerLink.Close()
 
-		nl.shutdownWg.Add(1)
+		nl.downWg.Add(1)
 		go func() {
-			defer nl.shutdownWg.Done()
+			defer nl.downWg.Done()
 
 			// wait for serve{Send,Recv} to complete before shutting connections down
 			//
@@ -207,11 +205,11 @@ func (nl *NodeLink) shutdown() {
 
 			nl.connMu.Lock()
 			for _, conn := range nl.connTab {
-				// NOTE anything waking up on Conn.closed must not lock
+				// NOTE anything waking up on Conn.down must not lock
 				// connMu - else it will deadlock.
 				conn.shutdown()
 			}
-			nl.connTab = nil	// clear + mark closed
+			nl.connTab = nil	// clear + mark down
 			nl.connMu.Unlock()
 		}()
 	})
@@ -222,7 +220,7 @@ func (nl *NodeLink) shutdown() {
 func (nl *NodeLink) Close() error {
 	atomic.StoreUint32(&nl.closeCalled, 1)
 	nl.shutdown()
-	nl.shutdownWg.Wait()
+	nl.downWg.Wait()
 	return nl.errClose
 }
 
@@ -268,7 +266,7 @@ func (nl *NodeLink) Accept() (*Conn, error) {
 	}
 }
 
-// errRecvShutdown returns appropriate error when c.closed is found ready in Recv
+// errRecvShutdown returns appropriate error when c.down is found ready in Recv
 func (c *Conn) errRecvShutdown() error {
 	switch {
 	case atomic.LoadUint32(&c.closeCalled) != 0:
@@ -335,8 +333,8 @@ func (nl *NodeLink) serveRecv() {
 			if nl.acceptq != nil {
 				// we are accepting new incoming connection
 				conn = nl.newConn(connId)
-				// XXX what if Accept exited because of just recently close(nl.closed)?
-				//     -> check nl.closed here too ?
+				// XXX what if Accept exited because of just recently close(nl.down)?
+				//     -> check nl.down here too ?
 				nl.acceptq <- conn
 			}
 		}
@@ -349,12 +347,12 @@ func (nl *NodeLink) serveRecv() {
 		}
 
 		// route packet to serving goroutine handler
-		// XXX what if Conn.Recv exited because of just recently close(nl.closed) ?
-		//     -> check nl.closed here too ?
+		// XXX what if Conn.Recv exited because of just recently close(nl.down) ?
+		//     -> check nl.down here too ?
 		conn.rxq <- pkt
 
 		// keep connMu locked until here: so that ^^^ `conn.rxq <- pkt` can be
-		// sure conn stays not closed e.g. by Conn.Close
+		// sure conn stays not down e.g. closed by Conn.Close
 		nl.connMu.Unlock()
 	}
 }