优化MMAP相关功能

internal/caches/list_memory.go

@@ -89,21 +89,21 @@ func (this *MemoryList) Add(hash string, item *Item) error {
 	return nil
 }
 
-func (this *MemoryList) Exist(hash string) (bool, error) {
+func (this *MemoryList) Exist(hash string) (bool, int64, error) {
 	this.locker.RLock()
 	defer this.locker.RUnlock()
 
 	prefix := this.prefix(hash)
 	itemMap, ok := this.itemMaps[prefix]
 	if !ok {
-		return false, nil
+		return false, -1, nil
 	}
 	item, ok := itemMap[hash]
 	if !ok {
-		return false, nil
+		return false, -1, nil
 	}
 
-	return !item.IsExpired(), nil
+	return !item.IsExpired(), -1, nil
 }
 
 // CleanPrefix 根据前缀进行清除