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package needle
import ( "fmt" "github.com/seaweedfs/seaweedfs/weed/glog" "github.com/seaweedfs/seaweedfs/weed/storage/backend" . "github.com/seaweedfs/seaweedfs/weed/storage/types" "github.com/seaweedfs/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, volumeOffset int64, buf []byte, writer io.Writer, needleOffset int64, size int64) (err error) { crc := CRC(0) for x := needleOffset; x < needleOffset+size; x += int64(len(buf)) { count, err := n.ReadNeedleData(r, volumeOffset, buf, x) toWrite := min(int64(count), needleOffset+size-x) if toWrite > 0 { crc = crc.Update(buf[0:toWrite]) if _, err = writer.Write(buf[0:toWrite]); err != nil { return fmt.Errorf("ReadNeedleData write: %v", err) } } if err != nil { if err == io.EOF { err = nil break } return fmt.Errorf("ReadNeedleData: %v", err) } if count <= 0 { break } } if needleOffset == 0 && size == int64(n.DataSize) && (n.Checksum != crc && uint32(n.Checksum) != crc.Value()) { // the crc.Value() function is to be deprecated. this double checking is for backward compatible.
return fmt.Errorf("ReadNeedleData checksum %v expected %v", crc, n.Checksum) } 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) (err error) {
bytes := make([]byte, NeedleHeaderSize+DataSizeSize)
count, err := r.ReadAt(bytes, offset) if count != NeedleHeaderSize+DataSizeSize || err != nil { return err } n.ParseNeedleHeader(bytes) if n.Size != size { if OffsetSize == 4 && offset < int64(MaxPossibleVolumeSize) { return ErrorSizeMismatch } }
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 metaSlice := make([]byte, int(metaSize))
count, err = r.ReadAt(metaSlice, startOffset) if err != nil && int64(count) == metaSize { err = nil } if err != nil { return err }
var index int index, err = n.readNeedleDataVersion2NonData(metaSlice)
n.Checksum = CRC(util.BytesToUint32(metaSlice[index : index+NeedleChecksumSize])) if version == Version3 { n.AppendAtNs = util.BytesToUint64(metaSlice[index+NeedleChecksumSize : index+NeedleChecksumSize+TimestampSize]) }
return err
}
func min(x, y int64) int64 { if x < y { return x } return y }
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