Method openWriter

internal/caches/storage_file.go:478–727

(key string, expiredAt int64, status int, headerSize int, bodySize int64, maxSize int64, isPartial bool, isFlushing bool)

}

func (this *FileStorage) openWriter(key string, expiredAt int64, status int, headerSize int, bodySize int64, maxSize int64, isPartial bool, isFlushing bool) (Writer, error) {
	// 是否正在退出
	if teaconst.IsQuiting {
		return nil, ErrWritingUnavailable
	}

	// 是否已忽略
	if maxSize > 0 && this.ignoreKeys.Has(types.String(maxSize)+"$"+key) {
		return nil, ErrEntityTooLarge
	}

	// 检查磁盘是否超出容量
	// 需要在内存缓存之前执行，避免成功写进到了内存缓存，但无法刷到磁盘
	var capacityBytes = this.diskCapacityBytes()
	if capacityBytes > 0 && capacityBytes <= this.TotalDiskSize()+(32<<20 /** 余量 **/) {
		return nil, NewCapacityError("write file cache failed: over disk size, current: " + types.String(this.TotalDiskSize()) + ", capacity: " + types.String(capacityBytes))
	}

	// 先尝试内存缓存
	// 我们限定仅小文件优先存在内存中
	var maxMemorySize = FileToMemoryMaxSize
	if maxSize > 0 && maxSize < maxMemorySize {
		maxMemorySize = maxSize
	}
	var memoryStorage = this.memoryStorage
	if !isFlushing && !isPartial && memoryStorage != nil && ((bodySize > 0 && bodySize < maxMemorySize) || bodySize < 0) {
		writer, err := memoryStorage.OpenWriter(key, expiredAt, status, headerSize, bodySize, maxMemorySize, false)
		if err == nil {
			return writer, nil
		}

		// 如果队列满了，则等待
		if errors.Is(err, ErrWritingQueueFull) {
			return nil, err
		}

		if IsCapacityError(err) && bodySize > 0 && memoryStorage.totalDirtySize > (128<<20) {
			return nil, err
		}
	}

	// 是否正在写入
	var isOk = false
	sharedWritingFileKeyLocker.Lock()
	_, ok := sharedWritingFileKeyMap[key]
	if ok {
		sharedWritingFileKeyLocker.Unlock()
		return nil, fmt.Errorf("%w(001)", ErrFileIsWriting)
	}

	sharedWritingFileKeyMap[key] = zero.New()
	sharedWritingFileKeyLocker.Unlock()
	defer func() {
		if !isOk {
			sharedWritingFileKeyLocker.Lock()
			delete(sharedWritingFileKeyMap, key)
			sharedWritingFileKeyLocker.Unlock()
		}