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package filer2
import ( "context" "fmt" "io" "sync"
"github.com/chrislusf/seaweedfs/weed/glog" "github.com/chrislusf/seaweedfs/weed/pb/filer_pb" "github.com/chrislusf/seaweedfs/weed/util/chunk_cache" "github.com/chrislusf/seaweedfs/weed/wdclient" )
type ChunkReadAt struct { masterClient *wdclient.MasterClient chunkViews []*ChunkView lookupFileId func(fileId string) (targetUrl string, err error) readerLock sync.Mutex fileSize int64
chunkCache chunk_cache.ChunkCache }
// var _ = io.ReaderAt(&ChunkReadAt{})
type LookupFileIdFunctionType func(fileId string) (targetUrl string, err error)
func LookupFn(filerClient filer_pb.FilerClient) LookupFileIdFunctionType { return func(fileId string) (targetUrl string, err error) { err = filerClient.WithFilerClient(func(client filer_pb.SeaweedFilerClient) error { vid := VolumeId(fileId) resp, err := client.LookupVolume(context.Background(), &filer_pb.LookupVolumeRequest{ VolumeIds: []string{vid}, }) if err != nil { return err }
locations := resp.LocationsMap[vid] if locations == nil || len(locations.Locations) == 0 { glog.V(0).Infof("failed to locate %s", fileId) return fmt.Errorf("failed to locate %s", fileId) }
volumeServerAddress := filerClient.AdjustedUrl(locations.Locations[0].Url)
targetUrl = fmt.Sprintf("http://%s/%s", volumeServerAddress, fileId)
return nil }) return } }
func NewChunkReaderAtFromClient(filerClient filer_pb.FilerClient, chunkViews []*ChunkView, chunkCache chunk_cache.ChunkCache, fileSize int64) *ChunkReadAt {
return &ChunkReadAt{ chunkViews: chunkViews, lookupFileId: LookupFn(filerClient), chunkCache: chunkCache, fileSize: fileSize, } }
func (c *ChunkReadAt) ReadAt(p []byte, offset int64) (n int, err error) {
c.readerLock.Lock() defer c.readerLock.Unlock()
glog.V(4).Infof("ReadAt [%d,%d) of total file size %d bytes %d chunk views", offset, offset+int64(len(p)), c.fileSize, len(c.chunkViews)) return c.doReadAt(p[n:], offset+int64(n)) }
func (c *ChunkReadAt) doReadAt(p []byte, offset int64) (n int, err error) {
var buffer []byte startOffset, remaining := offset, int64(len(p)) for i, chunk := range c.chunkViews { if remaining <= 0 { break } if startOffset < chunk.LogicOffset { gap := int(chunk.LogicOffset - startOffset) glog.V(4).Infof("zero [%d,%d)", startOffset, startOffset+int64(gap)) n += int(min(int64(gap), remaining)) startOffset, remaining = chunk.LogicOffset, remaining-int64(gap) if remaining <= 0 { break } } // fmt.Printf(">>> doReadAt [%d,%d), chunk[%d,%d)\n", offset, offset+int64(len(p)), chunk.LogicOffset, chunk.LogicOffset+int64(chunk.Size))
chunkStart, chunkStop := max(chunk.LogicOffset, startOffset), min(chunk.LogicOffset+int64(chunk.Size), startOffset+remaining) if chunkStart >= chunkStop { continue } glog.V(4).Infof("read [%d,%d), %d/%d chunk %s [%d,%d)", chunkStart, chunkStop, i, len(c.chunkViews), chunk.FileId, chunk.LogicOffset-chunk.Offset, chunk.LogicOffset-chunk.Offset+int64(chunk.Size)) buffer, err = c.readFromWholeChunkData(chunk) if err != nil { glog.Errorf("fetching chunk %+v: %v\n", chunk, err) return } bufferOffset := chunkStart - chunk.LogicOffset + chunk.Offset copied := copy(p[startOffset-offset:chunkStop-chunkStart+startOffset-offset], buffer[bufferOffset:bufferOffset+chunkStop-chunkStart]) n += copied startOffset, remaining = startOffset+int64(copied), remaining-int64(copied) }
glog.V(4).Infof("doReadAt [%d,%d), n:%v, err:%v", offset, offset+int64(len(p)), n, err)
if err == nil && remaining > 0 && c.fileSize > startOffset { delta := int(min(remaining, c.fileSize-startOffset)) glog.V(4).Infof("zero2 [%d,%d) of file size %d bytes", startOffset, startOffset+int64(delta), c.fileSize) n += delta }
if err == nil && offset+int64(len(p)) > c.fileSize { err = io.EOF } // fmt.Printf("~~~ filled %d, err: %v\n\n", n, err)
return
}
func (c *ChunkReadAt) readFromWholeChunkData(chunkView *ChunkView) (chunkData []byte, err error) {
glog.V(4).Infof("readFromWholeChunkData %s offset %d [%d,%d) size at least %d", chunkView.FileId, chunkView.Offset, chunkView.LogicOffset, chunkView.LogicOffset+int64(chunkView.Size), chunkView.ChunkSize)
chunkData = c.chunkCache.GetChunk(chunkView.FileId, chunkView.ChunkSize) if chunkData != nil { glog.V(4).Infof("cache hit %s [%d,%d)", chunkView.FileId, chunkView.LogicOffset-chunkView.Offset, chunkView.LogicOffset-chunkView.Offset+int64(len(chunkData))) } else { glog.V(4).Infof("doFetchFullChunkData %s", chunkView.FileId) chunkData, err = c.doFetchFullChunkData(chunkView.FileId, chunkView.CipherKey, chunkView.IsGzipped) if err != nil { return } c.chunkCache.SetChunk(chunkView.FileId, chunkData) }
return }
func (c *ChunkReadAt) doFetchFullChunkData(fileId string, cipherKey []byte, isGzipped bool) ([]byte, error) {
return fetchChunk(c.lookupFileId, fileId, cipherKey, isGzipped)
}
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