[#108] Collect eviction statistics for expired entries

* [#108] Collect eviction statistics for expired entries

* [Chore] Fix issues from linter

cache_test.go

@@ -165,6 +165,7 @@ func TestCache_SetWithTTL(t *testing.T) {
  var mutex sync.Mutex
  m := make(map[DeletionCause]int)
  c, err := MustBuilder[int, int](size).
+ CollectStats().
  InitialCapacity(size).
  WithTTL(time.Second).
  DeletionListener(func(key int, value int, cause DeletionCause) {
@@ -199,6 +200,14 @@ func TestCache_SetWithTTL(t *testing.T) {
  mutex.Unlock()
  t.Fatalf("cache was supposed to expire %d, but expired %d entries", size, e)
  }
+ if c.Stats().EvictedCount() != int64(m[Expired]) {
+ mutex.Unlock()
+ t.Fatalf(
+ "Eviction statistics are not collected for expiration. EvictedCount: %d, expired entries: %d",
+ c.Stats().EvictedCount(),
+ m[Expired],
+ )
+ }
  mutex.Unlock()
 
  m = make(map[DeletionCause]int)
@@ -240,6 +249,14 @@ func TestCache_SetWithTTL(t *testing.T) {
  if len(m) != 1 || m[Expired] != size {
  t.Fatalf("cache was supposed to expire %d, but expired %d entries", size, m[Expired])
  }
+ if c.Stats().EvictedCount() != int64(m[Expired]) {
+ mutex.Unlock()
+ t.Fatalf(
+ "Eviction statistics are not collected for expiration. EvictedCount: %d, expired entries: %d",
+ c.Stats().EvictedCount(),
+ m[Expired],
+ )
+ }
 }
 
 func TestCache_Delete(t *testing.T) {

internal/core/cache.go

@@ -381,6 +381,8 @@ func (c *Cache[K, V]) deleteExpiredNode(n node.Node[K, V]) {
  if deleted != nil {
  n.Die()
  c.notifyDeletion(n.Key(), n.Value(), Expired)
+ c.stats.IncEvictedCount()
+ c.stats.AddEvictedCost(n.Cost())
  }
 }
 

internal/hashtable/map.go

@@ -83,11 +83,13 @@ type table[K comparable] struct {
 }
 
 func (t *table[K]) addSize(bucketIdx uint64, delta int) {
+ //nolint:gosec // there will never be an overflow
  counterIdx := uint64(len(t.size)-1) & bucketIdx
  atomic.AddInt64(&t.size[counterIdx].c, int64(delta))
 }
 
 func (t *table[K]) addSizePlain(bucketIdx uint64, delta int) {
+ //nolint:gosec // there will never be an overflow
  counterIdx := uint64(len(t.size)-1) & bucketIdx
  t.size[counterIdx].c += int64(delta)
 }
@@ -159,6 +161,7 @@ func newTable[K comparable](bucketCount int, prevHasher maphash.Hasher[K]) *tabl
  counterLength = maxCounterLength
  }
  counter := make([]paddedCounter, counterLength)
+ //nolint:gosec // there will never be an overflow
  mask := uint64(len(buckets) - 1)
  t := &table[K]{
  buckets: buckets,
@@ -435,6 +438,7 @@ func (m *Map[K, V]) resize(known *table[K], hint resizeHint) {
  if hint != clearHint {
  for i := 0; i < tableLen; i++ {
  copied := m.copyBuckets(&t.buckets[i], nt)
+ //nolint:gosec // there will never be an overflow
  nt.addSizePlain(uint64(i), copied)
  }
  }