seaweedfs/weed/filer2/stream.go

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package filer2
import (
"bytes"
"io"
"math"
"strings"
"github.com/chrislusf/seaweedfs/weed/glog"
"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
"github.com/chrislusf/seaweedfs/weed/util"
"github.com/chrislusf/seaweedfs/weed/wdclient"
)
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func StreamContent(masterClient *wdclient.MasterClient, w io.Writer, chunks []*filer_pb.FileChunk, offset int64, size int64) error {
chunkViews := ViewFromChunks(chunks, offset, size)
fileId2Url := make(map[string]string)
for _, chunkView := range chunkViews {
urlString, err := masterClient.LookupFileId(chunkView.FileId)
if err != nil {
glog.V(1).Infof("operation LookupFileId %s failed, err: %v", chunkView.FileId, err)
return err
}
fileId2Url[chunkView.FileId] = urlString
}
for _, chunkView := range chunkViews {
urlString := fileId2Url[chunkView.FileId]
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err := util.ReadUrlAsStream(urlString, chunkView.CipherKey, chunkView.IsGzipped, chunkView.IsFullChunk, chunkView.Offset, int(chunkView.Size), func(data []byte) {
w.Write(data)
})
if err != nil {
glog.V(1).Infof("read %s failed, err: %v", chunkView.FileId, err)
return err
}
}
return nil
}
type ChunkStreamReader struct {
masterClient *wdclient.MasterClient
chunkViews []*ChunkView
logicOffset int64
buffer []byte
bufferOffset int64
bufferPos int
chunkIndex int
lookupFileId func(fileId string) (targetUrl string, err error)
}
var _ = io.ReadSeeker(&ChunkStreamReader{})
func NewChunkStreamReaderFromFiler(masterClient *wdclient.MasterClient, chunks []*filer_pb.FileChunk) *ChunkStreamReader {
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chunkViews := ViewFromChunks(chunks, 0, math.MaxInt32)
return &ChunkStreamReader{
chunkViews: chunkViews,
lookupFileId: func(fileId string) (targetUrl string, err error) {
return masterClient.LookupFileId(fileId)
},
}
}
func (c *ChunkStreamReader) Read(p []byte) (n int, err error) {
if c.isBufferEmpty() {
if c.chunkIndex >= len(c.chunkViews) {
return 0, io.EOF
}
chunkView := c.chunkViews[c.chunkIndex]
c.fetchChunkToBuffer(chunkView)
c.chunkIndex++
}
n = copy(p, c.buffer[c.bufferPos:])
c.bufferPos += n
return
}
func (c *ChunkStreamReader) isBufferEmpty() bool {
return len(c.buffer) <= c.bufferPos
}
func (c *ChunkStreamReader) Seek(offset int64, whence int) (int64, error) {
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var totalSize int64
for _, chunk := range c.chunkViews {
totalSize += int64(chunk.Size)
}
var err error
switch whence {
case io.SeekStart:
case io.SeekCurrent:
offset += c.bufferOffset + int64(c.bufferPos)
case io.SeekEnd:
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offset = totalSize + offset
}
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if offset > totalSize {
err = io.ErrUnexpectedEOF
}
for i, chunk := range c.chunkViews {
if chunk.LogicOffset <= offset && offset < chunk.LogicOffset+int64(chunk.Size) {
if c.isBufferEmpty() || c.bufferOffset != chunk.LogicOffset {
c.fetchChunkToBuffer(chunk)
c.chunkIndex = i + 1
break
}
}
}
c.bufferPos = int(offset - c.bufferOffset)
return offset, err
}
func (c *ChunkStreamReader) fetchChunkToBuffer(chunkView *ChunkView) error {
urlString, err := c.lookupFileId(chunkView.FileId)
if err != nil {
glog.V(1).Infof("operation LookupFileId %s failed, err: %v", chunkView.FileId, err)
return err
}
var buffer bytes.Buffer
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err = util.ReadUrlAsStream(urlString, chunkView.CipherKey, chunkView.IsGzipped, chunkView.IsFullChunk, chunkView.Offset, int(chunkView.Size), func(data []byte) {
buffer.Write(data)
})
if err != nil {
glog.V(1).Infof("read %s failed, err: %v", chunkView.FileId, err)
return err
}
c.buffer = buffer.Bytes()
c.bufferPos = 0
c.bufferOffset = chunkView.LogicOffset
// glog.V(0).Infof("read %s [%d,%d)", chunkView.FileId, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size))
return nil
}
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func VolumeId(fileId string) string {
lastCommaIndex := strings.LastIndex(fileId, ",")
if lastCommaIndex > 0 {
return fileId[:lastCommaIndex]
}
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return fileId
}