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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" )
// 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 == io.EOF && int64(count) == sizeToRead { err = nil } 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) { defer func() { if r := recover(); r != nil { err = fmt.Errorf("panic occurred: %+v", r) } }()
bytes := make([]byte, NeedleHeaderSize+DataSizeSize)
count, err := r.ReadAt(bytes, offset) if err == io.EOF && count == NeedleHeaderSize+DataSizeSize { err = nil } 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 if size.IsValid() { 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 if size.IsValid() { 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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