Method OpenFileReader

internal/utils/bfs/blocks_file.go:169–219

(fileHash string, isPartial bool)

}

func (this *BlocksFile) OpenFileReader(fileHash string, isPartial bool) (*FileReader, error) {
	err := CheckHashErr(fileHash)
	if err != nil {
		return nil, err
	}

	this.mu.RLock()
	err = this.checkStatus()
	this.mu.RUnlock()
	if err != nil {
		return nil, err
	}

	// 是否存在
	header, ok := this.mFile.CloneFileHeader(fileHash)
	if !ok {
		return nil, os.ErrNotExist
	}

	// TODO 对于partial content，需要传入ranges，用来判断是否有交集

	if header.IsWriting {
		return nil, ErrFileIsWriting
	}

	if !isPartial && !header.IsCompleted {
		return nil, os.ErrNotExist
	}

	// 先尝试从Pool中获取
	select {
	case reader := <-this.readerPool:
		if reader == nil {
			return nil, ErrClosed
		}
		reader.Reset(header)
		atomic.AddInt32(&this.countRefs, 1)
		return reader, nil
	default:
	}

	AckReadThread()
	fp, err := os.Open(this.fp.Name())
	ReleaseReadThread()
	if err != nil {
		return nil, err
	}

	atomic.AddInt32(&this.countRefs, 1)
	return NewFileReader(this, fp, header), nil
}

func (this *BlocksFile) CloseFileReader(reader *FileReader) error {
	defer atomic.AddInt32(&this.countRefs, -1)