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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 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 offset+int64(n) >= 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(5).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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