.github/workflows/ci.yml

@@ -0,0 +1,32 @@
+name: build
+
+on:
+  push:
+    branches:
+    tags:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: set up go 1.19
+        uses: actions/setup-go@v1
+        with:
+          go-version: 1.19
+        id: go
+
+      - name: checkout
+        uses: actions/checkout@v2
+
+      - name: build and test
+        run: |
+          go test -timeout=60s -race
+          go build -race
+
+      - name: install golangci-lint
+        run: curl -sfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh| sh -s -- -b $GITHUB_WORKSPACE v1.50.1
+
+      - name: run golangci-lint
+        run: $GITHUB_WORKSPACE/golangci-lint run --out-format=github-actions

.golangci.yml

@@ -0,0 +1,30 @@
+linters:
+  enable:
+    - megacheck
+    - revive
+    - govet
+    - unconvert
+    - megacheck
+    - gas
+    - gocyclo
+    - dupl
+    - misspell
+    - unparam
+    - unused
+    - typecheck
+    - ineffassign
+    - stylecheck
+    - exportloopref
+    - gocritic
+    - nakedret
+    - gosimple
+    - prealloc
+  fast: false
+  disable-all: true
+
+issues:
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - dupl
+  exclude-use-default: false

2q.go

@@ -44,7 +44,7 @@ func New2Q(size int) (*TwoQueueCache, error) {
 
 // New2QParams creates a new TwoQueueCache using the provided
 // parameter values.
-func New2QParams(size int, recentRatio float64, ghostRatio float64) (*TwoQueueCache, error) {
+func New2QParams(size int, recentRatio, ghostRatio float64) (*TwoQueueCache, error) {
 	if size <= 0 {
 		return nil, fmt.Errorf("invalid size")
 	}
@@ -138,7 +138,6 @@ func (c *TwoQueueCache) Add(key, value interface{}) {
 	// Add to the recently seen list
 	c.ensureSpace(false)
 	c.recent.Add(key, value)
-	return
 }
 
 // ensureSpace is used to ensure we have space in the cache

2q_test.go

@@ -1,7 +1,6 @@
 package lru
 
 import (
-	"math/rand"
 	"testing"
 )
 
@@ -13,7 +12,7 @@ func Benchmark2Q_Rand(b *testing.B) {
 
 	trace := make([]int64, b.N*2)
 	for i := 0; i < b.N*2; i++ {
-		trace[i] = rand.Int63() % 32768
+		trace[i] = getRand(b) % 32768
 	}
 
 	b.ResetTimer()
@@ -43,9 +42,9 @@ func Benchmark2Q_Freq(b *testing.B) {
 	trace := make([]int64, b.N*2)
 	for i := 0; i < b.N*2; i++ {
 		if i%2 == 0 {
-			trace[i] = rand.Int63() % 16384
+			trace[i] = getRand(b) % 16384
 		} else {
-			trace[i] = rand.Int63() % 32768
+			trace[i] = getRand(b) % 32768
 		}
 	}
 
@@ -75,8 +74,8 @@ func Test2Q_RandomOps(t *testing.T) {
 
 	n := 200000
 	for i := 0; i < n; i++ {
-		key := rand.Int63() % 512
-		r := rand.Int63()
+		key := getRand(t) % 512
+		r := getRand(t)
 		switch r % 3 {
 		case 0:
 			l.Add(key, key)

LICENSE

@@ -1,3 +1,5 @@
+Copyright (c) 2014 HashiCorp, Inc.
+
 Mozilla Public License, version 2.0
 
 1. Definitions

README.md

@@ -7,7 +7,7 @@ thread safe LRU cache. It is based on the cache in Groupcache.
 Documentation
 =============
 
-Full docs are available on [Godoc](http://godoc.org/github.com/hashicorp/golang-lru)
+Full docs are available on [Godoc](https://pkg.go.dev/github.com/hashicorp/golang-lru)
 
 Example
 =======

arc.go

@@ -173,7 +173,6 @@ func (c *ARCCache) Add(key, value interface{}) {
 
 	// Add to the recently seen list
 	c.t1.Add(key, value)
-	return
 }
 
 // replace is used to adaptively evict from either T1 or T2

arc_test.go

@@ -18,7 +18,7 @@ func BenchmarkARC_Rand(b *testing.B) {
 
 	trace := make([]int64, b.N*2)
 	for i := 0; i < b.N*2; i++ {
-		trace[i] = rand.Int63() % 32768
+		trace[i] = getRand(b) % 32768
 	}
 
 	b.ResetTimer()
@@ -48,9 +48,9 @@ func BenchmarkARC_Freq(b *testing.B) {
 	trace := make([]int64, b.N*2)
 	for i := 0; i < b.N*2; i++ {
 		if i%2 == 0 {
-			trace[i] = rand.Int63() % 16384
+			trace[i] = getRand(b) % 16384
 		} else {
-			trace[i] = rand.Int63() % 32768
+			trace[i] = getRand(b) % 32768
 		}
 	}
 
@@ -80,8 +80,8 @@ func TestARC_RandomOps(t *testing.T) {
 
 	n := 200000
 	for i := 0; i < n; i++ {
-		key := rand.Int63() % 512
-		r := rand.Int63()
+		key := getRand(t) % 512
+		r := getRand(t)
 		switch r % 3 {
 		case 0:
 			l.Add(key, key)

lru.go

@@ -6,10 +6,17 @@ import (
 	"github.com/hashicorp/golang-lru/simplelru"
 )
 
+const (
+	// DefaultEvictedBufferSize defines the default buffer size to store evicted key/val
+	DefaultEvictedBufferSize = 16
+)
+
 // Cache is a thread-safe fixed size LRU cache.
 type Cache struct {
-	lru  simplelru.LRUCache
-	lock sync.RWMutex
+	lru                      *simplelru.LRU
+	evictedKeys, evictedVals []interface{}
+	onEvictedCB              func(k, v interface{})
+	lock                     sync.RWMutex
 }
 
 // New creates an LRU of the given size.
@@ -19,30 +26,63 @@ func New(size int) (*Cache, error) {
 
 // NewWithEvict constructs a fixed size cache with the given eviction
 // callback.
-func NewWithEvict(size int, onEvicted func(key interface{}, value interface{})) (*Cache, error) {
-	lru, err := simplelru.NewLRU(size, simplelru.EvictCallback(onEvicted))
-	if err != nil {
-		return nil, err
+func NewWithEvict(size int, onEvicted func(key, value interface{})) (c *Cache, err error) {
+	// create a cache with default settings
+	c = &Cache{
+		onEvictedCB: onEvicted,
 	}
-	c := &Cache{
-		lru: lru,
+	if onEvicted != nil {
+		c.initEvictBuffers()
+		onEvicted = c.onEvicted
 	}
-	return c, nil
+	c.lru, err = simplelru.NewLRU(size, onEvicted)
+	return
+}
+
+func (c *Cache) initEvictBuffers() {
+	c.evictedKeys = make([]interface{}, 0, DefaultEvictedBufferSize)
+	c.evictedVals = make([]interface{}, 0, DefaultEvictedBufferSize)
+}
+
+// onEvicted save evicted key/val and sent in externally registered callback
+// outside of critical section
+func (c *Cache) onEvicted(k, v interface{}) {
+	c.evictedKeys = append(c.evictedKeys, k)
+	c.evictedVals = append(c.evictedVals, v)
 }
 
 // Purge is used to completely clear the cache.
 func (c *Cache) Purge() {
+	var ks, vs []interface{}
 	c.lock.Lock()
 	c.lru.Purge()
+	if c.onEvictedCB != nil && len(c.evictedKeys) > 0 {
+		ks, vs = c.evictedKeys, c.evictedVals
+		c.initEvictBuffers()
+	}
 	c.lock.Unlock()
+	// invoke callback outside of critical section
+	if c.onEvictedCB != nil {
+		for i := 0; i < len(ks); i++ {
+			c.onEvictedCB(ks[i], vs[i])
+		}
+	}
 }
 
 // Add adds a value to the cache. Returns true if an eviction occurred.
 func (c *Cache) Add(key, value interface{}) (evicted bool) {
+	var k, v interface{}
 	c.lock.Lock()
 	evicted = c.lru.Add(key, value)
+	if c.onEvictedCB != nil && evicted {
+		k, v = c.evictedKeys[0], c.evictedVals[0]
+		c.evictedKeys, c.evictedVals = c.evictedKeys[:0], c.evictedVals[:0]
+	}
 	c.lock.Unlock()
-	return evicted
+	if c.onEvictedCB != nil && evicted {
+		c.onEvictedCB(k, v)
+	}
+	return
 }
 
 // Get looks up a key's value from the cache.
@@ -75,61 +115,102 @@ func (c *Cache) Peek(key interface{}) (value interface{}, ok bool) {
 // recent-ness or deleting it for being stale, and if not, adds the value.
 // Returns whether found and whether an eviction occurred.
 func (c *Cache) ContainsOrAdd(key, value interface{}) (ok, evicted bool) {
+	var k, v interface{}
 	c.lock.Lock()
-	defer c.lock.Unlock()
-
 	if c.lru.Contains(key) {
+		c.lock.Unlock()
 		return true, false
 	}
 	evicted = c.lru.Add(key, value)
+	if c.onEvictedCB != nil && evicted {
+		k, v = c.evictedKeys[0], c.evictedVals[0]
+		c.evictedKeys, c.evictedVals = c.evictedKeys[:0], c.evictedVals[:0]
+	}
+	c.lock.Unlock()
+	if c.onEvictedCB != nil && evicted {
+		c.onEvictedCB(k, v)
+	}
 	return false, evicted
 }
 
 // PeekOrAdd checks if a key is in the cache without updating the
 // recent-ness or deleting it for being stale, and if not, adds the value.
 // Returns whether found and whether an eviction occurred.
 func (c *Cache) PeekOrAdd(key, value interface{}) (previous interface{}, ok, evicted bool) {
+	var k, v interface{}
 	c.lock.Lock()
-	defer c.lock.Unlock()
-
 	previous, ok = c.lru.Peek(key)
 	if ok {
+		c.lock.Unlock()
 		return previous, true, false
 	}
-
 	evicted = c.lru.Add(key, value)
+	if c.onEvictedCB != nil && evicted {
+		k, v = c.evictedKeys[0], c.evictedVals[0]
+		c.evictedKeys, c.evictedVals = c.evictedKeys[:0], c.evictedVals[:0]
+	}
+	c.lock.Unlock()
+	if c.onEvictedCB != nil && evicted {
+		c.onEvictedCB(k, v)
+	}
 	return nil, false, evicted
 }
 
 // Remove removes the provided key from the cache.
 func (c *Cache) Remove(key interface{}) (present bool) {
+	var k, v interface{}
 	c.lock.Lock()
 	present = c.lru.Remove(key)
+	if c.onEvictedCB != nil && present {
+		k, v = c.evictedKeys[0], c.evictedVals[0]
+		c.evictedKeys, c.evictedVals = c.evictedKeys[:0], c.evictedVals[:0]
+	}
 	c.lock.Unlock()
+	if c.onEvictedCB != nil && present {
+		c.onEvictedCB(k, v)
+	}
 	return
 }
 
 // Resize changes the cache size.
 func (c *Cache) Resize(size int) (evicted int) {
+	var ks, vs []interface{}
 	c.lock.Lock()
 	evicted = c.lru.Resize(size)
+	if c.onEvictedCB != nil && evicted > 0 {
+		ks, vs = c.evictedKeys, c.evictedVals
+		c.initEvictBuffers()
+	}
 	c.lock.Unlock()
+	if c.onEvictedCB != nil && evicted > 0 {
+		for i := 0; i < len(ks); i++ {
+			c.onEvictedCB(ks[i], vs[i])
+		}
+	}
 	return evicted
 }
 
 // RemoveOldest removes the oldest item from the cache.
-func (c *Cache) RemoveOldest() (key interface{}, value interface{}, ok bool) {
+func (c *Cache) RemoveOldest() (key, value interface{}, ok bool) {
+	var k, v interface{}
 	c.lock.Lock()
 	key, value, ok = c.lru.RemoveOldest()
+	if c.onEvictedCB != nil && ok {
+		k, v = c.evictedKeys[0], c.evictedVals[0]
+		c.evictedKeys, c.evictedVals = c.evictedKeys[:0], c.evictedVals[:0]
+	}
 	c.lock.Unlock()
+	if c.onEvictedCB != nil && ok {
+		c.onEvictedCB(k, v)
+	}
 	return
 }
 
 // GetOldest returns the oldest entry
-func (c *Cache) GetOldest() (key interface{}, value interface{}, ok bool) {
-	c.lock.Lock()
+func (c *Cache) GetOldest() (key, value interface{}, ok bool) {
+	c.lock.RLock()
 	key, value, ok = c.lru.GetOldest()
-	c.lock.Unlock()
+	c.lock.RUnlock()
 	return
 }