feat: correct the way of handling expired cache

Signed-off-by: Rueian <[email protected]>

Author: rueian

cache.go

@@ -206,33 +206,42 @@ type flatentry struct {
 
 func (f *flatentry) insert(e *flatentry) {
 	f.size += e.size
+	f.ttl = e.ttl
 	f.mu.Lock()
 	e.ovfl = f.ovfl
 	f.ovfl = e
 	f.mu.Unlock()
 }
 
 func (f *flatentry) find(cmd string, ts int64) ([]byte, bool) {
-	for next := f; next != nil; {
-		if ts >= next.ttl {
-			return nil, true
-		}
+	if f == nil {
+		return nil, false
+	}
+	if ts >= f.ttl {
+		return nil, true
+	}
+	return f._find(cmd), false
+}
+
+func (f *flatentry) _find(cmd string) []byte {
+	for next := f; ; {
 		if cmd == next.cmd {
-			return next.val, false
+			return next.val
 		}
 		next.mu.RLock()
 		ovfl := next.ovfl
 		next.mu.RUnlock()
-		next = ovfl
+		if next = ovfl; next == nil {
+			return nil
+		}
 	}
-	return nil, false
 }
 
 const lrBatchSize = 64
 const flattEntrySize = unsafe.Sizeof(flatentry{})
 
 type lrBatch struct {
-	m map[*flatentry]bool
+	m map[*flatentry]struct{}
 }
 
 func NewFlattenCache(limit int) CacheStore {
@@ -247,7 +256,7 @@ func NewFlattenCache(limit int) CacheStore {
 	f.head.next = unsafe.Pointer(f.tail)
 	f.tail.prev = unsafe.Pointer(f.head)
 	f.lrup = sync.Pool{New: func() any {
-		b := &lrBatch{m: make(map[*flatentry]bool, lrBatchSize)}
+		b := &lrBatch{m: make(map[*flatentry]struct{}, lrBatchSize)}
 		runtime.SetFinalizer(b, func(b *lrBatch) {
 			if len(b.m) >= 0 {
 				f.mu.Lock()
@@ -292,13 +301,9 @@ func (f *flatten) llTail(e *flatentry) {
 }
 
 func (f *flatten) llTailBatch(b *lrBatch) {
-	for e, expired := range b.m {
+	for e := range b.m {
 		if e.mark == f.mark {
-			if expired {
-				f.remove(e)
-			} else {
-				f.llTail(e)
-			}
+			f.llTail(e)
 		}
 	}
 	clear(b.m)
@@ -315,20 +320,18 @@ func (f *flatten) Flight(key, cmd string, ttl time.Duration, now time.Time) (Red
 	e := f.cache[key]
 	f.mu.RUnlock()
 	ts := now.UnixMilli()
-	if v, expired := e.find(cmd, ts); v != nil || expired {
+	if v, _ := e.find(cmd, ts); v != nil {
 		batch := f.lrup.Get().(*lrBatch)
-		batch.m[e] = expired
+		batch.m[e] = struct{}{}
 		if len(batch.m) >= lrBatchSize {
 			f.mu.Lock()
 			f.llTailBatch(batch)
 			f.mu.Unlock()
 		}
 		f.lrup.Put(batch)
-		if v != nil {
-			var ret RedisMessage
-			_ = ret.CacheUnmarshalView(v)
-			return ret, nil
-		}
+		var ret RedisMessage
+		_ = ret.CacheUnmarshalView(v)
+		return ret, nil
 	}
 	fk := key + cmd
 	f.mu.RLock()
@@ -382,7 +385,12 @@ func (f *flatten) Update(key, cmd string, val RedisMessage) (sxat int64) {
 				f.remove(e)
 				ep = e.next
 			}
-			if e := f.cache[key]; e == nil {
+			e := f.cache[key]
+			if e != nil && e._find(cmd) != nil {
+				f.remove(e)
+				e = nil
+			}
+			if e == nil {
 				fe.key = key
 				f.cache[key] = fe
 				f.llAdd(fe)