mirror of
https://github.com/chrislusf/seaweedfs
synced 2024-05-20 02:10:20 +02:00
112 lines
3.3 KiB
Go
112 lines
3.3 KiB
Go
package needle
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import (
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"fmt"
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"github.com/chrislusf/seaweedfs/weed/glog"
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"github.com/chrislusf/seaweedfs/weed/storage/backend"
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. "github.com/chrislusf/seaweedfs/weed/storage/types"
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"github.com/chrislusf/seaweedfs/weed/util"
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"io"
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)
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// ReadNeedleDataInto uses a needle without n.Data to read the content into an io.Writer
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func (n *Needle) ReadNeedleDataInto(r backend.BackendStorageFile, volumeOffset int64, buf []byte, writer io.Writer, needleOffset int64, size int64) (err error) {
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crc := CRC(0)
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for x := needleOffset; x < needleOffset+size; x += int64(len(buf)) {
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count, err := n.ReadNeedleData(r, volumeOffset, buf, x)
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toWrite := min(int64(count), needleOffset+size-x)
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if toWrite > 0 {
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crc = crc.Update(buf[0:toWrite])
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if _, err = writer.Write(buf[0:toWrite]); err != nil {
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return fmt.Errorf("ReadNeedleData write: %v", err)
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}
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}
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if err != nil {
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if err == io.EOF {
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err = nil
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break
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}
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return fmt.Errorf("ReadNeedleData: %v", err)
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}
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if count <= 0 {
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break
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}
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}
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if needleOffset == 0 && size == int64(n.DataSize) && (n.Checksum != crc && uint32(n.Checksum) != crc.Value()) {
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// the crc.Value() function is to be deprecated. this double checking is for backward compatible.
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return fmt.Errorf("ReadNeedleData checksum %v expected %v", crc, n.Checksum)
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}
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return nil
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}
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// ReadNeedleData uses a needle without n.Data to read the content
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// volumeOffset: the offset within the volume
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// needleOffset: the offset within the needle Data
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func (n *Needle) ReadNeedleData(r backend.BackendStorageFile, volumeOffset int64, data []byte, needleOffset int64) (count int, err error) {
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sizeToRead := min(int64(len(data)), int64(n.DataSize)-needleOffset)
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if sizeToRead <= 0 {
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return 0, io.EOF
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}
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startOffset := volumeOffset + NeedleHeaderSize + DataSizeSize + needleOffset
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count, err = r.ReadAt(data[:sizeToRead], startOffset)
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if err != nil {
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fileSize, _, _ := r.GetStat()
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glog.Errorf("%s read %d %d size %d at offset %d fileSize %d: %v", r.Name(), n.Id, needleOffset, sizeToRead, volumeOffset, fileSize, err)
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}
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return
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}
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// ReadNeedleMeta fills all metadata except the n.Data
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func (n *Needle) ReadNeedleMeta(r backend.BackendStorageFile, offset int64, size Size, version Version) (err error) {
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bytes := make([]byte, NeedleHeaderSize+DataSizeSize)
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count, err := r.ReadAt(bytes, offset)
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if count != NeedleHeaderSize+DataSizeSize || err != nil {
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return err
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}
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n.ParseNeedleHeader(bytes)
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if n.Size != size {
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if OffsetSize == 4 && offset < int64(MaxPossibleVolumeSize) {
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return ErrorSizeMismatch
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}
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}
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n.DataSize = util.BytesToUint32(bytes[NeedleHeaderSize : NeedleHeaderSize+DataSizeSize])
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startOffset := offset + NeedleHeaderSize + DataSizeSize + int64(n.DataSize)
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dataSize := GetActualSize(size, version)
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stopOffset := offset + dataSize
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metaSize := stopOffset - startOffset
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metaSlice := make([]byte, int(metaSize))
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count, err = r.ReadAt(metaSlice, startOffset)
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if err != nil && int64(count) == metaSize {
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err = nil
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}
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if err != nil {
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return err
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}
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var index int
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index, err = n.readNeedleDataVersion2NonData(metaSlice)
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n.Checksum = CRC(util.BytesToUint32(metaSlice[index : index+NeedleChecksumSize]))
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if version == Version3 {
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n.AppendAtNs = util.BytesToUint64(metaSlice[index+NeedleChecksumSize : index+NeedleChecksumSize+TimestampSize])
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}
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return err
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}
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func min(x, y int64) int64 {
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if x < y {
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return x
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}
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return y
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}
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