From 45c44aee50db5991d468504be08c16a3a62207fb Mon Sep 17 00:00:00 2001
From: David Hill <dhill@mindcry.org>
Date: Mon, 5 Nov 2018 18:39:28 -0500
Subject: [PATCH] [slack]: cleanup previous commit

- move global vars to struct
- use defer, which fixes refreshInProgress being set while unlocked
---
 bridge/slack/helpers.go | 47 ++++++++++++++++++++---------------------
 bridge/slack/slack.go   | 20 ++++++++++++------
 2 files changed, 37 insertions(+), 30 deletions(-)

diff --git a/bridge/slack/helpers.go b/bridge/slack/helpers.go
index 4abe79cd..23d5816a 100644
--- a/bridge/slack/helpers.go
+++ b/bridge/slack/helpers.go
@@ -4,7 +4,6 @@ import (
 	"fmt"
 	"regexp"
 	"strings"
-	"sync"
 	"time"
 
 	"github.com/nlopes/slack"
@@ -61,22 +60,17 @@ func (b *Bslack) getChannelByID(ID string) (*slack.Channel, error) {
 
 const minimumRefreshInterval = 10 * time.Second
 
-var (
-	refreshMutex           sync.Mutex
-	refreshInProgress      bool
-	earliestChannelRefresh = time.Now()
-	earliestUserRefresh    = time.Now()
-)
-
 func (b *Bslack) populateUsers() {
-	refreshMutex.Lock()
-	if time.Now().Before(earliestUserRefresh) || refreshInProgress {
-		b.Log.Debugf("Not refreshing user list as it was done less than %d seconds ago.", int(minimumRefreshInterval.Seconds()))
-		refreshMutex.Unlock()
+	b.refreshMutex.Lock()
+	if time.Now().Before(b.earliestUserRefresh) || b.refreshInProgress {
+		b.Log.Debugf("Not refreshing user list as it was done less than %v ago.",
+			minimumRefreshInterval)
+		b.refreshMutex.Unlock()
+
 		return
 	}
-	refreshInProgress = true
-	refreshMutex.Unlock()
+	b.refreshInProgress = true
+	b.refreshMutex.Unlock()
 
 	users, err := b.sc.GetUsers()
 	if err != nil {
@@ -95,19 +89,22 @@ func (b *Bslack) populateUsers() {
 	defer b.usersMutex.Unlock()
 	b.users = newUsers
 
-	earliestUserRefresh = time.Now().Add(minimumRefreshInterval)
-	refreshInProgress = false
+	b.refreshMutex.Lock()
+	defer b.refreshMutex.Unlock()
+	b.earliestUserRefresh = time.Now().Add(minimumRefreshInterval)
+	b.refreshInProgress = false
 }
 
 func (b *Bslack) populateChannels() {
-	refreshMutex.Lock()
-	if time.Now().Before(earliestChannelRefresh) || refreshInProgress {
-		b.Log.Debugf("Not refreshing channel list as it was done less than %d seconds ago.", int(minimumRefreshInterval.Seconds()))
-		refreshMutex.Unlock()
+	b.refreshMutex.Lock()
+	if time.Now().Before(b.earliestChannelRefresh) || b.refreshInProgress {
+		b.Log.Debugf("Not refreshing channel list as it was done less than %v seconds ago.",
+			minimumRefreshInterval)
+		b.refreshMutex.Unlock()
 		return
 	}
-	refreshInProgress = true
-	refreshMutex.Unlock()
+	b.refreshInProgress = true
+	b.refreshMutex.Unlock()
 
 	newChannelsByID := map[string]*slack.Channel{}
 	newChannelsByName := map[string]*slack.Channel{}
@@ -139,8 +136,10 @@ func (b *Bslack) populateChannels() {
 	b.channelsByID = newChannelsByID
 	b.channelsByName = newChannelsByName
 
-	earliestChannelRefresh = time.Now().Add(minimumRefreshInterval)
-	refreshInProgress = false
+	b.refreshMutex.Lock()
+	defer b.refreshMutex.Unlock()
+	b.earliestChannelRefresh = time.Now().Add(minimumRefreshInterval)
+	b.refreshInProgress = false
 }
 
 var (
diff --git a/bridge/slack/slack.go b/bridge/slack/slack.go
index 924f4131..c1386a46 100644
--- a/bridge/slack/slack.go
+++ b/bridge/slack/slack.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/42wim/matterbridge/bridge"
 	"github.com/42wim/matterbridge/bridge/config"
@@ -34,6 +35,11 @@ type Bslack struct {
 	channelsByID   map[string]*slack.Channel
 	channelsByName map[string]*slack.Channel
 	channelsMutex  sync.RWMutex
+
+	refreshInProgress      bool
+	earliestChannelRefresh time.Time
+	earliestUserRefresh    time.Time
+	refreshMutex           sync.Mutex
 }
 
 const (
@@ -68,12 +74,14 @@ func New(cfg *bridge.Config) bridge.Bridger {
 		cfg.Log.Fatalf("Could not create LRU cache for Slack bridge: %v", err)
 	}
 	b := &Bslack{
-		Config:         cfg,
-		uuid:           xid.New().String(),
-		cache:          newCache,
-		users:          map[string]*slack.User{},
-		channelsByID:   map[string]*slack.Channel{},
-		channelsByName: map[string]*slack.Channel{},
+		Config:                 cfg,
+		uuid:                   xid.New().String(),
+		cache:                  newCache,
+		users:                  map[string]*slack.User{},
+		channelsByID:           map[string]*slack.Channel{},
+		channelsByName:         map[string]*slack.Channel{},
+		earliestChannelRefresh: time.Now(),
+		earliestUserRefresh:    time.Now(),
 	}
 	return b
 }