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package filer
import (
"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"sync"
)
const SectionSize = 2 * 1024 * 1024 * 128 // 256MiB
type SectionIndex int64
type FileChunkSection struct {
sectionIndex SectionIndex
chunks []*filer_pb.FileChunk
entryViewCache []VisibleInterval
chunkViews []*ChunkView
reader *ChunkReadAt
lock sync.Mutex
}
func (section *FileChunkSection) addChunk(chunk *filer_pb.FileChunk) error {
section.lock.Lock()
defer section.lock.Unlock()
section.chunks = append(section.chunks, chunk)
// FIXME: this can be improved to an incremental change
section.entryViewCache = nil
return nil
}
func (section *FileChunkSection) readDataAt(group *ChunkGroup, fileSize int64, buff []byte, offset int64) (n int, tsNs int64, err error) {
section.lock.Lock()
defer section.lock.Unlock()
section.setupForRead(group, fileSize)
return section.reader.ReadAtWithTime(buff, offset)
}
func (section *FileChunkSection) setupForRead(group *ChunkGroup, fileSize int64) {
if section.entryViewCache == nil {
section.entryViewCache = readResolvedChunks(section.chunks)
section.chunks, _ = SeparateGarbageChunks(section.entryViewCache, section.chunks)
if section.reader != nil {
_ = section.reader.Close()
section.reader = nil
}
}
if section.reader == nil {
chunkViews := ViewFromVisibleIntervals(section.entryViewCache, int64(section.sectionIndex)*SectionSize, (int64(section.sectionIndex)+1)*SectionSize)
section.reader = NewChunkReaderAtFromClient(group.lookupFn, chunkViews, group.chunkCache, min(int64(section.sectionIndex+1)*SectionSize, fileSize))
}
}
func (section *FileChunkSection) DataStartOffset(group *ChunkGroup, offset int64, fileSize int64) int64 {
section.lock.Lock()
defer section.lock.Unlock()
section.setupForRead(group, fileSize)
for _, visible := range section.entryViewCache {
if visible.stop <= offset {
continue
}
if offset < visible.start {
return offset
}
return offset
}
return -1
}
func (section *FileChunkSection) NextStopOffset(group *ChunkGroup, offset int64, fileSize int64) int64 {
section.lock.Lock()
defer section.lock.Unlock()
section.setupForRead(group, fileSize)
isAfterOffset := false
for _, visible := range section.entryViewCache {
if !isAfterOffset {
if visible.stop <= offset {
continue
}
isAfterOffset = true
}
if offset < visible.start {
return offset
}
// now visible.start <= offset
if offset < visible.stop {
offset = visible.stop
}
}
return offset
}