From 00a49ab5774d43ee085450e16a2e5d6b6d54a978 Mon Sep 17 00:00:00 2001
From: wxing1292 <wxing1292@users.noreply.github.com>
Date: Wed, 12 Jan 2022 14:49:08 -0800
Subject: [PATCH] Remove removal function away from LRU cache for simplicity
 (#2372)

* Remove element removal function since this functionality is not used & brings complexity
---
 common/cache/cache.go    |  4 ---
 common/cache/lru.go      |  5 ---
 common/cache/lru_test.go | 71 +++-------------------------------------
 3 files changed, 4 insertions(+), 76 deletions(-)

diff --git a/common/cache/cache.go b/common/cache/cache.go
index 20a8c4c719c..77c51e82afe 100644
--- a/common/cache/cache.go
+++ b/common/cache/cache.go
@@ -66,10 +66,6 @@ type Options struct {
 
 	// Pin prevents in-use objects from getting evicted.
 	Pin bool
-
-	// RemovedFunc is an optional function called when an element
-	// is scheduled for deletion
-	RemovedFunc RemovedFunc
 }
 
 // SimpleOptions provides options that can be used to configure SimpleCache
diff --git a/common/cache/lru.go b/common/cache/lru.go
index ce3134fc969..c87cefe372f 100644
--- a/common/cache/lru.go
+++ b/common/cache/lru.go
@@ -45,7 +45,6 @@ type (
 		maxSize  int
 		ttl      time.Duration
 		pin      bool
-		rmFunc   RemovedFunc
 	}
 
 	iteratorImpl struct {
@@ -141,7 +140,6 @@ func New(maxSize int, opts *Options) Cache {
 		ttl:      opts.TTL,
 		maxSize:  maxSize,
 		pin:      opts.Pin,
-		rmFunc:   opts.RemovedFunc,
 	}
 }
 
@@ -308,9 +306,6 @@ func (c *lru) putInternal(key interface{}, value interface{}, allowUpdate bool)
 
 func (c *lru) deleteInternal(element *list.Element) {
 	entry := c.byAccess.Remove(element).(*entryImpl)
-	if c.rmFunc != nil {
-		go c.rmFunc(entry.value)
-	}
 	delete(c.byKey, entry.key)
 }
 
diff --git a/common/cache/lru_test.go b/common/cache/lru_test.go
index 7d0c4cf3415..4433bba23c5 100644
--- a/common/cache/lru_test.go
+++ b/common/cache/lru_test.go
@@ -156,64 +156,21 @@ func TestLRUCacheConcurrentAccess(t *testing.T) {
 	wg.Wait()
 }
 
-func TestRemoveFunc(t *testing.T) {
-	ch := make(chan bool)
-	cache := New(5, &Options{
-		RemovedFunc: func(i interface{}) {
-			_, ok := i.(*testing.T)
-			assert.True(t, ok)
-			ch <- true
-		},
-	})
-
-	cache.Put("testing", t)
-	cache.Delete("testing")
-	assert.Nil(t, cache.Get("testing"))
-
-	timeout := time.NewTimer(time.Millisecond * 300)
-	select {
-	case b := <-ch:
-		assert.True(t, b)
-	case <-timeout.C:
-		t.Error("RemovedFunc did not send true on channel ch")
-	}
-}
-
-func TestRemovedFuncWithTTL(t *testing.T) {
-	ch := make(chan bool)
+func TestTTL(t *testing.T) {
 	cache := New(5, &Options{
 		TTL: time.Millisecond * 50,
-		RemovedFunc: func(i interface{}) {
-			_, ok := i.(*testing.T)
-			assert.True(t, ok)
-			ch <- true
-		},
 	})
 
 	cache.Put("A", t)
 	assert.Equal(t, t, cache.Get("A"))
 	time.Sleep(time.Millisecond * 100)
 	assert.Nil(t, cache.Get("A"))
-
-	timeout := time.NewTimer(time.Millisecond * 300)
-	select {
-	case b := <-ch:
-		assert.True(t, b)
-	case <-timeout.C:
-		t.Error("RemovedFunc did not send true on channel ch")
-	}
 }
 
-func TestRemovedFuncWithTTL_Pin(t *testing.T) {
-	ch := make(chan bool)
+func TestTTLWithPin(t *testing.T) {
 	cache := New(5, &Options{
 		TTL: time.Millisecond * 50,
 		Pin: true,
-		RemovedFunc: func(i interface{}) {
-			_, ok := i.(*testing.T)
-			assert.True(t, ok)
-			ch <- true
-		},
 	})
 
 	_, err := cache.PutIfNotExist("A", t)
@@ -226,26 +183,12 @@ func TestRemovedFuncWithTTL_Pin(t *testing.T) {
 	cache.Release("A")
 	cache.Release("A")
 	assert.Nil(t, cache.Get("A"))
-
-	timeout := time.NewTimer(time.Millisecond * 300)
-	select {
-	case b := <-ch:
-		assert.True(t, b)
-	case <-timeout.C:
-		t.Error("RemovedFunc did not send true on channel ch")
-	}
 }
 
-func TestRemovedFuncMaxSize_Pin_MidItem(t *testing.T) {
-	ch := make(chan bool)
+func TestMaxSizeWithPin_MidItem(t *testing.T) {
 	cache := New(2, &Options{
 		TTL: time.Millisecond * 50,
 		Pin: true,
-		RemovedFunc: func(i interface{}) {
-			_, ok := i.(*testing.T)
-			assert.True(t, ok)
-			ch <- true
-		},
 	})
 
 	_, err := cache.PutIfNotExist("A", t)
@@ -277,16 +220,10 @@ func TestRemovedFuncMaxSize_Pin_MidItem(t *testing.T) {
 	assert.Nil(t, cache.Get("C"))
 }
 
-func TestRemovedFuncMaxSize_Pin_LastItem(t *testing.T) {
-	ch := make(chan bool)
+func TestMaxSizeWithPin_LastItem(t *testing.T) {
 	cache := New(2, &Options{
 		TTL: time.Millisecond * 50,
 		Pin: true,
-		RemovedFunc: func(i interface{}) {
-			_, ok := i.(*testing.T)
-			assert.True(t, ok)
-			ch <- true
-		},
 	})
 
 	_, err := cache.PutIfNotExist("A", t)