From 0db57db1f118b8c27d6e9407705ee0b1945b2ef6 Mon Sep 17 00:00:00 2001
From: Josh Baker <joshbaker77@gmail.com>
Date: Sat, 30 Sep 2017 07:34:08 -0700
Subject: [PATCH] moved follow counter to atomic

---
 controller/checksum.go   |  4 ++--
 controller/controller.go | 10 ++++------
 controller/follow.go     | 17 ++++++++---------
 3 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/controller/checksum.go b/controller/checksum.go
index e9c047dd..bca5100e 100644
--- a/controller/checksum.go
+++ b/controller/checksum.go
@@ -138,13 +138,13 @@ func getEndOfLastValuePositionInFile(fname string, startPos int64) (int64, error
 
 // followCheckSome is not a full checksum. It just "checks some" data.
 // We will do some various checksums on the leader until we find the correct position to start at.
-func (c *Controller) followCheckSome(addr string, followc uint64) (pos int64, err error) {
+func (c *Controller) followCheckSome(addr string, followc int) (pos int64, err error) {
 	if core.ShowDebugMessages {
 		log.Debug("follow:", addr, ":check some")
 	}
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	if c.followc != followc {
+	if c.followc.get() != followc {
 		return 0, errNoLongerFollowing
 	}
 	if c.aofsz < checksumsz {
diff --git a/controller/controller.go b/controller/controller.go
index e84ff733..7e658f40 100644
--- a/controller/controller.go
+++ b/controller/controller.go
@@ -78,7 +78,7 @@ type Controller struct {
 	aofsz     int
 	dir       string
 	config    *Config
-	followc   uint64 // counter increases when follow property changes
+	followc   aint // counter increases when follow property changes
 	follows   map[*bytes.Buffer]bool
 	fcond     *sync.Cond
 	lstack    []*commandDetailsT
@@ -183,12 +183,10 @@ func ListenAndServeEx(host string, port int, dir string, ln *net.Listener, http
 	}
 	c.fillExpiresList()
 	if c.config.followHost() != "" {
-		go c.follow(c.config.followHost(), c.config.followPort(), c.followc)
+		go c.follow(c.config.followHost(), c.config.followPort(), c.followc.get())
 	}
 	defer func() {
-		c.mu.Lock()
-		c.followc++ // this will force any follow communication to die
-		c.mu.Unlock()
+		c.followc.add(1) // this will force any follow communication to die
 	}()
 	go c.processLives()
 	go c.watchMemory()
@@ -204,8 +202,8 @@ func ListenAndServeEx(host string, port int, dir string, ln *net.Listener, http
 		if cc, ok := c.conns[conn]; ok {
 			cc.last = time.Now()
 		}
-		c.statsTotalCommands.add(1)
 		c.mu.Unlock()
+		c.statsTotalCommands.add(1)
 		err := c.handleInputCommand(conn, msg, w)
 		if err != nil {
 			if err.Error() == "going live" {
diff --git a/controller/follow.go b/controller/follow.go
index 901ec9f6..18827323 100644
--- a/controller/follow.go
+++ b/controller/follow.go
@@ -85,10 +85,10 @@ func (c *Controller) cmdFollow(msg *server.Message) (res string, err error) {
 	}
 	c.config.write(false)
 	if update {
-		c.followc++
+		c.followc.add(1)
 		if c.config.followHost() != "" {
 			log.Infof("following new host '%s' '%s'.", host, sport)
-			go c.follow(c.config.followHost(), c.config.followPort(), c.followc)
+			go c.follow(c.config.followHost(), c.config.followPort(), c.followc.get())
 		} else {
 			log.Infof("following no one")
 		}
@@ -112,10 +112,10 @@ func doServer(conn *Conn) (map[string]string, error) {
 	return m, err
 }
 
-func (c *Controller) followHandleCommand(values []resp.Value, followc uint64, w io.Writer) (int, error) {
+func (c *Controller) followHandleCommand(values []resp.Value, followc int, w io.Writer) (int, error) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-	if c.followc != followc {
+	if c.followc.get() != followc {
 		return c.aofsz, errNoLongerFollowing
 	}
 	msg := &server.Message{
@@ -148,12 +148,11 @@ func (c *Controller) followDoLeaderAuth(conn *Conn, auth string) error {
 	return nil
 }
 
-func (c *Controller) followStep(host string, port int, followc uint64) error {
-	c.mu.Lock()
-	if c.followc != followc {
-		c.mu.Unlock()
+func (c *Controller) followStep(host string, port int, followc int) error {
+	if c.followc.get() != followc {
 		return errNoLongerFollowing
 	}
+	c.mu.Lock()
 	c.fcup = false
 	auth := c.config.leaderAuth()
 	c.mu.Unlock()
@@ -247,7 +246,7 @@ func (c *Controller) followStep(host string, port int, followc uint64) error {
 	}
 }
 
-func (c *Controller) follow(host string, port int, followc uint64) {
+func (c *Controller) follow(host string, port int, followc int) {
 	for {
 		err := c.followStep(host, port, followc)
 		if err == errNoLongerFollowing {