Change Set to accept time.Duration and move the original function to SetAbs

b

.github/workflows/test.yml

@@ -0,0 +1,14 @@
+on: [push, pull_request]
+name: Test
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [1.23.x]
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/setup-go@v5
+      with:
+        go-version: ${{ matrix.go-version }}
+    - uses: actions/checkout@v4
+    - run: go test ./...

cache.go

@@ -1,7 +1,6 @@
 package cache
 
 import (
-	"github.com/MrMelon54/rescheduler"
 	"sync"
 	"time"
 )
@@ -19,7 +18,6 @@ func timeUntil(t time.Time) time.Duration { return t.Sub(timeNow()) }
 type Cache[K comparable, V any] struct {
 	items    sync.Map
 	chain    *keyed[K] // linked list of to-expire keys
-	sched    *rescheduler.Rescheduler
 	close    chan struct{}
 	chainAdd chan keyed[K]
 	chainDel chan K
@@ -54,7 +52,7 @@ func New[K comparable, V any]() *Cache[K, V] {
 		chainAdd: make(chan keyed[K], 1),
 		chainDel: make(chan K, 1),
 	}
-	c.sched = rescheduler.NewRescheduler(c.cleaner)
+	go c.cleaner()
 	return c
 }
 
@@ -68,70 +66,33 @@ func (c *Cache[K, V]) Close() {
 // cleaner handles removing expired keys. The chainAdd and chainDel channels are
 // handled here to prevent race conditions. This ensures the expiry timer can be
 // stopped before modifying the chain.
-//
-// The cleaner is stopped whenever the chain is empty due to there being no chain
-// to manage.
 func (c *Cache[K, V]) cleaner() {
-	// cleaner is always called from Set or Delete methods with a value sent on chainAdd or chainDel
-	select {
-	case node := <-c.chainAdd:
-		c.chainInsert(node)
-	case key := <-c.chainDel:
-		c.chainSplice(key)
-	default:
-		// skip if chainAdd or chainDel isn't ready
-
-		println("Skip first select")
-	}
-
-	// at this point if the chain is empty then exit
-	if c.chain == nil {
-		return
-	}
-
-	// create a timer for the next expiry
-	t := time.NewTimer(timeUntil(c.chain.expires))
-
 	for {
 		select {
 		case <-c.close:
 			// exit the cleaner goroutine
 			return
 		case node := <-c.chainAdd:
-			// stop the timer safely
-			if !t.Stop() {
-				<-t.C
-			}
-			// the chain will not be empty after this insert so no check is required
 			c.chainInsert(node)
 		case key := <-c.chainDel:
-			// stop the timer safely
-			if !t.Stop() {
-				<-t.C
-			}
 			c.chainSplice(key)
-		case <-t.C:
+		case <-c.nextExpiry():
-			// if there is no chain then kill the expiry scheduler
-			if c.chain == nil {
-				return
-			}
-
 			// remove all expired entries
 			for c.chain != nil && c.chain.HasExpired() {
-				c.items.Delete(c.chain.data)
+				c.items.CompareAndDelete(c.chain.data, c.chain.item)
 				c.chain = c.chain.next
 			}
 		}
-
-		// if there is no chain then kill the expiry scheduler
-		if c.chain == nil {
-			return
-		}
-
-		t.Reset(timeUntil(c.chain.expires))
 	}
 }
 
+func (c *Cache[K, V]) nextExpiry() <-chan time.Time {
+	if c.chain == nil {
+		return make(chan time.Time)
+	}
+	return time.After(timeUntil(c.chain.expires))
+}
+
 func (c *Cache[K, V]) chainInsert(node keyed[K]) {
 	// quick path for an empty chain
 	if c.chain == nil {
@@ -232,10 +193,17 @@ func (c *Cache[K, V]) SetPermanent(key K, value V) {
 	c.items.Store(key, i)
 }
 
-// Set adds an item to the cache with an expiry date.
+// Set adds an item to the cache with an expiry duration.
 //
 // If an item is added with the same key then this item with be overwritten.
-func (c *Cache[K, V]) Set(key K, value V, expires time.Time) {
+func (c *Cache[K, V]) Set(key K, value V, expires time.Duration) {
+	c.SetAbs(key, value, timeNow().Add(expires))
+}
+
+// SetAbs adds an item to the cache with an expiry date.
+//
+// If an item is added with the same key then this item with be overwritten.
+func (c *Cache[K, V]) SetAbs(key K, value V, expires time.Time) {
 	// if the cache is closed then just return
 	select {
 	case <-c.close:
@@ -250,7 +218,6 @@ func (c *Cache[K, V]) Set(key K, value V, expires time.Time) {
 	i := &item[V]{data: value, expires: expires}
 	c.items.Store(key, i)
 	c.chainAdd <- keyed[K]{item: item[K]{data: key, expires: expires}}
-	c.sched.Run()
 }
 
 // Delete removes an item from the cache.
@@ -264,7 +231,6 @@ func (c *Cache[K, V]) Delete(key K) {
 
 	c.items.Delete(key)
 	c.chainDel <- key
-	c.sched.Run()
 }
 
 // Range calls f with every key-value pair, which has not expired, currently

cache_test.go

@@ -71,8 +71,26 @@ func TestCache_SetPermanent(t *testing.T) {
 }
 
 func TestCache_Set(t *testing.T) {
+	timeNow = func() time.Time { return time.Date(nextYear, time.January, 1, 0, 0, 0, 0, time.UTC) }
+
 	c := New[string, string]()
-	c.Set("a", "b", time.Date(nextYear, time.January, 1, 0, 0, 0, 0, time.UTC))
+	c.Set("a", "b", 5*time.Minute)
+
+	value, ok := c.items.Load("a")
+	v := value.(*item[string])
+	assert.Equal(t, item[string]{
+		data:    "b",
+		expires: timeNow().Add(5 * time.Minute),
+	}, *v)
+	assert.True(t, ok)
+
+	value, ok = c.items.Load("b")
+	assert.False(t, ok)
+}
+
+func TestCache_SetAbs(t *testing.T) {
+	c := New[string, string]()
+	c.SetAbs("a", "b", time.Date(nextYear, time.January, 1, 0, 0, 0, 0, time.UTC))
 
 	value, ok := c.items.Load("a")
 	v := value.(*item[string])
@@ -93,7 +111,7 @@ func TestCache_Delete(t *testing.T) {
 	c.Delete("a")
 
 	// scheduler should finish after deleting the item
-	c.sched.Wait()
+	time.Sleep(time.Second)
 	assert.Nil(t, c.chain)
 }
 
@@ -110,11 +128,10 @@ func TestCache_Range(t *testing.T) {
 }
 
 func TestCache_Cleaner(t *testing.T) {
-	timeNow = func() time.Time { return time.Now() }
+	timeNow = time.Now
 
-	n := time.Now().Add(2 * time.Second)
 	c := New[string, string]()
-	c.Set("a", "b", n)
+	c.Set("a", "b", 2*time.Second)
 
 	// check before expiry
 	time.Sleep(time.Second)
@@ -129,6 +146,44 @@ func TestCache_Cleaner(t *testing.T) {
 	assert.Equal(t, "", get)
 
 	// scheduler should finish after the chain is empty
-	c.sched.Wait()
+	time.Sleep(time.Second)
 	assert.Nil(t, c.chain)
 }
+
+func TestCache_UpdateExpiry(t *testing.T) {
+	timeNow = time.Now
+
+	c := New[string, string]()
+	c.Set("a", "b", 2*time.Second)
+
+	time.Sleep(time.Second)
+	get, b := c.Get("a")
+	assert.True(t, b)
+	assert.Equal(t, "b", get)
+
+	c.Set("a", "b", 5*time.Second)
+
+	// after expiry of the first set call
+	time.Sleep(2 * time.Second)
+	get, b = c.Get("a")
+	assert.True(t, b)
+	assert.Equal(t, "b", get)
+}
+
+func TestCache_ClearerDeath(t *testing.T) {
+	timeNow = time.Now
+
+	c := New[string, string]()
+
+	time.Sleep(10 * time.Millisecond)
+
+	var added bool
+	go func() {
+		c.chainAdd <- keyed[string]{item: item[string]{data: "a"}}
+		c.chainAdd <- keyed[string]{item: item[string]{data: "b"}}
+		added = true
+	}()
+
+	time.Sleep(10 * time.Millisecond)
+	assert.True(t, added)
+}

go.mod

@@ -1,11 +1,8 @@
 module github.com/1f349/cache
 
-go 1.21.1
+go 1.23
 
-require (
+require github.com/stretchr/testify v1.10.0
-	github.com/MrMelon54/rescheduler v0.0.2
-	github.com/stretchr/testify v1.8.4
-)
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect

go.sum

@@ -1,11 +1,9 @@
-github.com/MrMelon54/rescheduler v0.0.2 h1:efrRwr0BYlkaXFucZDjQqRyIawZiMEAnzjea46Bs9Oc=
-github.com/MrMelon54/rescheduler v0.0.2/go.mod h1:OQDFtZHdS4/qA/r7rtJUQA22/hbpnZ9MGQCXOPjhC6w=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=