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" ) 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] 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 { 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) { 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: offset = totalSize + offset } 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 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 } func VolumeId(fileId string) string { lastCommaIndex := strings.LastIndex(fileId, ",") if lastCommaIndex > 0 { return fileId[:lastCommaIndex] } return fileId }