mirror of
https://github.com/seaweedfs/seaweedfs.git
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105 lines
2.7 KiB
Go
105 lines
2.7 KiB
Go
package storage
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import (
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"bufio"
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"fmt"
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"github.com/chrislusf/seaweedfs/weed/util"
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"io"
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"time"
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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/needle"
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. "github.com/chrislusf/seaweedfs/weed/storage/types"
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)
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func (v *Volume) StreamWrite(n *needle.Needle, data io.Reader, dataSize uint32) (err error) {
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v.dataFileAccessLock.Lock()
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defer v.dataFileAccessLock.Unlock()
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df, ok := v.DataBackend.(*backend.DiskFile)
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if !ok {
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return fmt.Errorf("unexpected volume backend")
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}
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offset, _, _ := v.DataBackend.GetStat()
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header := make([]byte, NeedleHeaderSize+TimestampSize) // adding timestamp to reuse it and avoid extra allocation
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CookieToBytes(header[0:CookieSize], n.Cookie)
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NeedleIdToBytes(header[CookieSize:CookieSize+NeedleIdSize], n.Id)
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n.Size = 4 + Size(dataSize) + 1
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SizeToBytes(header[CookieSize+NeedleIdSize:CookieSize+NeedleIdSize+SizeSize], n.Size)
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n.DataSize = dataSize
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// needle header
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df.Write(header[0:NeedleHeaderSize])
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// data size and data
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util.Uint32toBytes(header[0:4], n.DataSize)
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df.Write(header[0:4])
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// write and calculate CRC
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crcWriter := needle.NewCRCwriter(df)
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io.Copy(crcWriter, io.LimitReader(data, int64(dataSize)))
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// flags
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util.Uint8toBytes(header[0:1], n.Flags)
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df.Write(header[0:1])
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// data checksum
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util.Uint32toBytes(header[0:needle.NeedleChecksumSize], crcWriter.Sum())
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// write timestamp, padding
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n.AppendAtNs = uint64(time.Now().UnixNano())
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util.Uint64toBytes(header[needle.NeedleChecksumSize:needle.NeedleChecksumSize+TimestampSize], n.AppendAtNs)
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padding := needle.PaddingLength(n.Size, needle.Version3)
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df.Write(header[0 : needle.NeedleChecksumSize+TimestampSize+padding])
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// add to needle map
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if err = v.nm.Put(n.Id, ToOffset(int64(offset)), n.Size); err != nil {
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glog.V(4).Infof("failed to save in needle map %d: %v", n.Id, err)
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}
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return
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}
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func (v *Volume) StreamRead(n *needle.Needle, writer io.Writer) (err error) {
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v.dataFileAccessLock.Lock()
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defer v.dataFileAccessLock.Unlock()
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nv, ok := v.nm.Get(n.Id)
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if !ok || nv.Offset.IsZero() {
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return ErrorNotFound
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}
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sr := &StreamReader{
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readerAt: v.DataBackend,
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offset: nv.Offset.ToActualOffset(),
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}
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bufReader := bufio.NewReader(sr)
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bufReader.Discard(NeedleHeaderSize)
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sizeBuf := make([]byte, 4)
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bufReader.Read(sizeBuf)
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if _, err = writer.Write(sizeBuf); err != nil {
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return err
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}
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dataSize := util.BytesToUint32(sizeBuf)
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_, err = io.Copy(writer, io.LimitReader(bufReader, int64(dataSize)))
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return
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}
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type StreamReader struct {
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offset int64
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readerAt io.ReaderAt
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}
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func (sr *StreamReader) Read(p []byte) (n int, err error) {
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n, err = sr.readerAt.ReadAt(p, sr.offset)
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if err != nil {
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return
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}
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sr.offset += int64(n)
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return
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}
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