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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, 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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