From 3f48f468acef1f5e44918b0ec37702095398d9bf Mon Sep 17 00:00:00 2001
From: Aarsh Shah <aarshkshah1992@gmail.com>
Date: Tue, 4 Feb 2020 20:05:16 +0530
Subject: [PATCH 1/3] replace lru cache blacklist implementation with a time
 cache

---
 blacklist.go      | 29 +++++++++++++----------------
 blacklist_test.go |  5 ++---
 2 files changed, 15 insertions(+), 19 deletions(-)

diff --git a/blacklist.go b/blacklist.go
index ba747d81..efc1420c 100644
--- a/blacklist.go
+++ b/blacklist.go
@@ -1,8 +1,10 @@
 package pubsub
 
 import (
-	lru "github.com/hashicorp/golang-lru"
+	"time"
+
 	"github.com/libp2p/go-libp2p-core/peer"
+	"github.com/whyrusleeping/timecache"
 )
 
 // Blacklist is an interface for peer blacklisting.
@@ -28,26 +30,21 @@ func (b MapBlacklist) Contains(p peer.ID) bool {
 	return ok
 }
 
-// LRUBlacklist is a blacklist implementation using an LRU cache
-type LRUBlacklist struct {
-	lru *lru.Cache
+// TimeCachedBlacklist is a blacklist implementation using a time cache
+type TimeCachedBlacklist struct {
+	tc *timecache.TimeCache
 }
 
-// NewLRUBlacklist creates a new LRUBlacklist with capacity cap
-func NewLRUBlacklist(cap int) (Blacklist, error) {
-	c, err := lru.New(cap)
-	if err != nil {
-		return nil, err
-	}
-
-	b := &LRUBlacklist{lru: c}
+// NewTimeCachedBlacklist creates a new TimeCachedBlacklist with the given expiry duration
+func NewTimeCachedBlacklist(expiry time.Duration) (Blacklist, error) {
+	b := &TimeCachedBlacklist{timecache.NewTimeCache(expiry)}
 	return b, nil
 }
 
-func (b LRUBlacklist) Add(p peer.ID) {
-	b.lru.Add(p, nil)
+func (b TimeCachedBlacklist) Add(p peer.ID) {
+	b.tc.Add(p.String())
 }
 
-func (b LRUBlacklist) Contains(p peer.ID) bool {
-	return b.lru.Contains(p)
+func (b TimeCachedBlacklist) Contains(p peer.ID) bool {
+	return b.tc.Has(p.String())
 }
diff --git a/blacklist_test.go b/blacklist_test.go
index b263b3ea..5b0bcc9f 100644
--- a/blacklist_test.go
+++ b/blacklist_test.go
@@ -20,8 +20,8 @@ func TestMapBlacklist(t *testing.T) {
 
 }
 
-func TestLRUBlacklist(t *testing.T) {
-	b, err := NewLRUBlacklist(10)
+func TestTimeCachedBlacklist(t *testing.T) {
+	b, err := NewTimeCachedBlacklist(10 * time.Minute)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -32,7 +32,6 @@ func TestLRUBlacklist(t *testing.T) {
 	if !b.Contains(p) {
 		t.Fatal("peer not in the blacklist")
 	}
-
 }
 
 func TestBlacklist(t *testing.T) {

From 677ca1025be681fcf9732ab5a0f456970c0a8fb8 Mon Sep 17 00:00:00 2001
From: Aarsh Shah <aarshkshah1992@gmail.com>
Date: Wed, 5 Feb 2020 14:13:21 +0530
Subject: [PATCH 2/3] added mutex to timecache

---
 blacklist.go | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/blacklist.go b/blacklist.go
index efc1420c..909a1ee9 100644
--- a/blacklist.go
+++ b/blacklist.go
@@ -1,6 +1,7 @@
 package pubsub
 
 import (
+	"sync"
 	"time"
 
 	"github.com/libp2p/go-libp2p-core/peer"
@@ -32,19 +33,25 @@ func (b MapBlacklist) Contains(p peer.ID) bool {
 
 // TimeCachedBlacklist is a blacklist implementation using a time cache
 type TimeCachedBlacklist struct {
+	sync.RWMutex
 	tc *timecache.TimeCache
 }
 
 // NewTimeCachedBlacklist creates a new TimeCachedBlacklist with the given expiry duration
 func NewTimeCachedBlacklist(expiry time.Duration) (Blacklist, error) {
-	b := &TimeCachedBlacklist{timecache.NewTimeCache(expiry)}
+	b := &TimeCachedBlacklist{tc: timecache.NewTimeCache(expiry)}
 	return b, nil
 }
 
-func (b TimeCachedBlacklist) Add(p peer.ID) {
+func (b *TimeCachedBlacklist) Add(p peer.ID) {
+	b.Lock()
 	b.tc.Add(p.String())
+	b.Unlock()
 }
 
-func (b TimeCachedBlacklist) Contains(p peer.ID) bool {
+func (b *TimeCachedBlacklist) Contains(p peer.ID) bool {
+	b.RLock()
+	defer b.RUnlock()
+
 	return b.tc.Has(p.String())
 }

From 6eeed58a50b5e2a62ccbb6bf299ec9efc3bf2955 Mon Sep 17 00:00:00 2001
From: Aarsh Shah <aarshkshah1992@gmail.com>
Date: Wed, 5 Feb 2020 14:33:20 +0530
Subject: [PATCH 3/3] defer unlocking

---
 blacklist.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/blacklist.go b/blacklist.go
index 909a1ee9..c8784b27 100644
--- a/blacklist.go
+++ b/blacklist.go
@@ -45,8 +45,9 @@ func NewTimeCachedBlacklist(expiry time.Duration) (Blacklist, error) {
 
 func (b *TimeCachedBlacklist) Add(p peer.ID) {
 	b.Lock()
+	defer b.Unlock()
+
 	b.tc.Add(p.String())
-	b.Unlock()
 }
 
 func (b *TimeCachedBlacklist) Contains(p peer.ID) bool {