package needle import ( "fmt" "github.com/chrislusf/seaweedfs/weed/glog" "github.com/chrislusf/seaweedfs/weed/storage/backend" . "github.com/chrislusf/seaweedfs/weed/storage/types" "github.com/chrislusf/seaweedfs/weed/util" "io" ) // ReadNeedleDataInto uses a needle without n.Data to read the content into an io.Writer func (n *Needle) ReadNeedleDataInto(r backend.BackendStorageFile, offset int64, buf []byte, writer io.Writer, expectedChecksumValue uint32) (err error) { crc := CRC(0) for x := 0; ; x += len(buf) { count, err := n.ReadNeedleData(r, offset, buf, int64(x)) if err != nil { if err == io.EOF { break } return fmt.Errorf("ReadNeedleData: %v", err) } if count > 0 { crc = crc.Update(buf[0:count]) if _, err = writer.Write(buf[0:count]); err != nil { return fmt.Errorf("ReadNeedleData write: %v", err) } } else { break } } if expectedChecksumValue != crc.Value() { return fmt.Errorf("ReadNeedleData checksum %v expected %v", crc.Value(), expectedChecksumValue) } return nil } // ReadNeedleData uses a needle without n.Data to read the content // volumeOffset: the offset within the volume // needleOffset: the offset within the needle Data func (n *Needle) ReadNeedleData(r backend.BackendStorageFile, volumeOffset int64, data []byte, needleOffset int64) (count int, err error) { sizeToRead := min(int64(len(data)), int64(n.DataSize)-needleOffset) if sizeToRead <= 0 { return 0, io.EOF } startOffset := volumeOffset + NeedleHeaderSize + DataSizeSize + needleOffset count, err = r.ReadAt(data[:sizeToRead], startOffset) if err != nil { fileSize, _, _ := r.GetStat() glog.Errorf("%s read %d %d size %d at offset %d fileSize %d: %v", r.Name(), n.Id, needleOffset, sizeToRead, volumeOffset, fileSize, err) } return } // ReadNeedleMeta fills all metadata except the n.Data func (n *Needle) ReadNeedleMeta(r backend.BackendStorageFile, offset int64, size Size, version Version) (checksumValue uint32, err error) { bytes := make([]byte, NeedleHeaderSize+DataSizeSize) count, err := r.ReadAt(bytes, offset) if count != NeedleHeaderSize+DataSizeSize || err != nil { return 0, err } n.ParseNeedleHeader(bytes) n.DataSize = util.BytesToUint32(bytes[NeedleHeaderSize : NeedleHeaderSize+DataSizeSize]) startOffset := offset + NeedleHeaderSize + DataSizeSize + int64(n.DataSize) dataSize := GetActualSize(size, version) stopOffset := offset + dataSize metaSize := stopOffset - startOffset fmt.Printf("offset %d dataSize %d\n", offset, dataSize) fmt.Printf("read needle meta [%d,%d) size %d\n", startOffset, stopOffset, metaSize) metaSlice := make([]byte, int(metaSize)) count, err = r.ReadAt(metaSlice, startOffset) if err != nil && int64(count) == metaSize { err = nil } if err != nil { return 0, err } var index int index, err = n.readNeedleDataVersion2NonData(metaSlice) checksumValue = util.BytesToUint32(metaSlice[index : index+NeedleChecksumSize]) if version == Version3 { n.AppendAtNs = util.BytesToUint64(metaSlice[index+NeedleChecksumSize : index+NeedleChecksumSize+TimestampSize]) } return checksumValue, err } func min(x, y int64) int64 { if x < y { return x } return y }