优化缓存相关代码

internal/caches/open_file_pool.go

@@ -31,6 +31,7 @@ func (this *OpenFilePool) Filename() string {
 func (this *OpenFilePool) Get() (*OpenFile, bool) {
 	select {
 	case file := <-this.c:
+		if file != nil {
 			err := file.SeekStart()
 			if err != nil {
 				_ = file.Close()
@@ -39,6 +40,8 @@ func (this *OpenFilePool) Get() (*OpenFile, bool) {
 			file.version = this.version
 
 			return file, true
+		}
+		return nil, false
 	default:
 		return nil, false
 	}

internal/caches/storage_file.go

@@ -710,9 +710,6 @@ func (this *FileStorage) Delete(key string) error {
 		return nil
 	}
 
-	this.locker.Lock()
-	defer this.locker.Unlock()
-
 	// 先尝试内存缓存
 	this.runMemoryStorageSafety(func(memoryStorage *MemoryStorage) {
 		_ = memoryStorage.Delete(key)
@@ -733,9 +730,6 @@ func (this *FileStorage) Delete(key string) error {
 
 // Stat 统计
 func (this *FileStorage) Stat() (*Stat, error) {
-	this.locker.RLock()
-	defer this.locker.RUnlock()
-
 	return this.list.Stat(func(hash string) bool {
 		return true
 	})
@@ -834,9 +828,6 @@ func (this *FileStorage) Purge(keys []string, urlType string) error {
 		return nil
 	}
 
-	this.locker.Lock()
-	defer this.locker.Unlock()
-
 	// 先尝试内存缓存
 	this.runMemoryStorageSafety(func(memoryStorage *MemoryStorage) {
 		_ = memoryStorage.Purge(keys, urlType)