Code quality improvements (#67)

* add golangci-lint configuration, fix discovered issues

* add GitHub Actions test and build and linter run

.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 1.14
+        uses: actions/setup-go@v1
+        with:
+          go-version: 1.14
+        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 v1.26.0
+
+      - name: run golangci-lint
+        run: $GITHUB_WORKSPACE/golangci-lint run --out-format=github-actions

.golangci.yml

@@ -0,0 +1,33 @@
+linters:
+  enable:
+    - megacheck
+    - golint
+    - govet
+    - unconvert
+    - megacheck
+    - structcheck
+    - gas
+    - gocyclo
+    - dupl
+    - misspell
+    - unparam
+    - varcheck
+    - deadcode
+    - typecheck
+    - ineffassign
+    - varcheck
+    - stylecheck
+    - scopelint
+    - 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

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

lru.go

@@ -118,15 +118,15 @@ func (c *Cache) Resize(size int) (evicted int) {
 }
 
 // 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) {
 	c.lock.Lock()
 	key, value, ok = c.lru.RemoveOldest()
 	c.lock.Unlock()
 	return
 }
 
 // GetOldest returns the oldest entry
-func (c *Cache) GetOldest() (key interface{}, value interface{}, ok bool) {
+func (c *Cache) GetOldest() (key, value interface{}, ok bool) {
 	c.lock.Lock()
 	key, value, ok = c.lru.GetOldest()
 	c.lock.Unlock()

lru_test.go

@@ -267,7 +267,7 @@ func TestLRUResize(t *testing.T) {
 	// Downsize
 	l.Add(1, 1)
 	l.Add(2, 2)
-	evicted := l.Resize(1);
+	evicted := l.Resize(1)
 	if evicted != 1 {
 		t.Errorf("1 element should have been evicted: %v", evicted)
 	}
@@ -281,7 +281,7 @@ func TestLRUResize(t *testing.T) {
 	}
 
 	// Upsize
-	evicted = l.Resize(2);
+	evicted = l.Resize(2)
 	if evicted != 0 {
 		t.Errorf("0 elements should have been evicted: %v", evicted)
 	}

simplelru/lru.go

@@ -25,7 +25,7 @@ type entry struct {
 // NewLRU constructs an LRU of the given size
 func NewLRU(size int, onEvict EvictCallback) (*LRU, error) {
 	if size <= 0 {
-		return nil, errors.New("Must provide a positive size")
+		return nil, errors.New("must provide a positive size")
 	}
 	c := &LRU{
 		size:      size,
@@ -109,7 +109,7 @@ func (c *LRU) Remove(key interface{}) (present bool) {
 }
 
 // RemoveOldest removes the oldest item from the cache.
-func (c *LRU) RemoveOldest() (key interface{}, value interface{}, ok bool) {
+func (c *LRU) RemoveOldest() (key, value interface{}, ok bool) {
 	ent := c.evictList.Back()
 	if ent != nil {
 		c.removeElement(ent)
@@ -120,7 +120,7 @@ func (c *LRU) RemoveOldest() (key interface{}, value interface{}, ok bool) {
 }
 
 // GetOldest returns the oldest entry
-func (c *LRU) GetOldest() (key interface{}, value interface{}, ok bool) {
+func (c *LRU) GetOldest() (key, value interface{}, ok bool) {
 	ent := c.evictList.Back()
 	if ent != nil {
 		kv := ent.Value.(*entry)

simplelru/lru_interface.go

@@ -1,3 +1,4 @@
+// Package simplelru provides simple LRU implementation based on build-in container/list.
 package simplelru
 
 // LRUCache is the interface for simple LRU cache.
@@ -34,6 +35,6 @@ type LRUCache interface {
 	// Clears all cache entries.
 	Purge()
 
-  // Resizes cache, returning number evicted
-  Resize(int) int
+	// Resizes cache, returning number evicted
+	Resize(int) int
 }

simplelru/lru_test.go

@@ -180,7 +180,7 @@ func TestLRU_Resize(t *testing.T) {
 	// Downsize
 	l.Add(1, 1)
 	l.Add(2, 2)
-	evicted := l.Resize(1);
+	evicted := l.Resize(1)
 	if evicted != 1 {
 		t.Errorf("1 element should have been evicted: %v", evicted)
 	}
@@ -194,7 +194,7 @@ func TestLRU_Resize(t *testing.T) {
 	}
 
 	// Upsize
-	evicted = l.Resize(2);
+	evicted = l.Resize(2)
 	if evicted != 0 {
 		t.Errorf("0 elements should have been evicted: %v", evicted)
 	}