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89 lines
2.5 KiB
Go
89 lines
2.5 KiB
Go
package needle
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import (
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"fmt"
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"github.com/seaweedfs/seaweedfs/weed/glog"
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"github.com/seaweedfs/seaweedfs/weed/storage/backend"
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. "github.com/seaweedfs/seaweedfs/weed/storage/types"
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"github.com/seaweedfs/seaweedfs/weed/util"
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"io"
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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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defer func() {
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if r := recover(); r != nil {
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err = fmt.Errorf("panic occurred: %+v", r)
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}
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}()
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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
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if size.IsValid() {
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startOffset = offset + NeedleHeaderSize + DataSizeSize + int64(n.DataSize)
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}
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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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if size.IsValid() {
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index, err = n.readNeedleDataVersion2NonData(metaSlice)
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}
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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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