1 files changed, 119 insertions, 0 deletions
diff --git a/weed/filer/filechunk_section.go b/weed/filer/filechunk_section.go
new file mode 100644
index 000000000..60c919569
--- /dev/null
+++ b/weed/filer/filechunk_section.go
@@ -0,0 +1,119 @@
+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
+	visibleIntervals *IntervalList[*VisibleInterval]
+	chunkViews       *IntervalList[*ChunkView]
+	reader           *ChunkReadAt
+	lock             sync.Mutex
+}
+
+func NewFileChunkSection(si SectionIndex) *FileChunkSection {
+	return &FileChunkSection{
+		sectionIndex: si,
+	}
+}
+
+func (section *FileChunkSection) addChunk(chunk *filer_pb.FileChunk) error {
+	section.lock.Lock()
+	defer section.lock.Unlock()
+
+	start, stop := max(int64(section.sectionIndex)*SectionSize, chunk.Offset), min(((int64(section.sectionIndex)+1)*SectionSize), chunk.Offset+int64(chunk.Size))
+
+	section.chunks = append(section.chunks, chunk)
+
+	if section.visibleIntervals != nil {
+		MergeIntoVisibles(section.visibleIntervals, start, stop, chunk)
+	}
+
+	if section.visibleIntervals != nil {
+		section.chunks, _ = SeparateGarbageChunks(section.visibleIntervals, section.chunks)
+	}
+
+	if section.chunkViews != nil {
+		MergeIntoChunkViews(section.chunkViews, start, stop, chunk)
+	}
+
+	return nil
+}
+
+func (section *FileChunkSection) setupForRead(group *ChunkGroup, fileSize int64) {
+	if section.visibleIntervals == nil {
+		section.visibleIntervals = readResolvedChunks(section.chunks, int64(section.sectionIndex)*SectionSize, (int64(section.sectionIndex)+1)*SectionSize)
+		section.chunks, _ = SeparateGarbageChunks(section.visibleIntervals, section.chunks)
+		if section.reader != nil {
+			_ = section.reader.Close()
+			section.reader = nil
+		}
+	}
+	if section.chunkViews == nil {
+		section.chunkViews = ViewFromVisibleIntervals(section.visibleIntervals, int64(section.sectionIndex)*SectionSize, (int64(section.sectionIndex)+1)*SectionSize)
+	}
+
+	if section.reader == nil {
+		section.reader = NewChunkReaderAtFromClient(group.lookupFn, section.chunkViews, group.chunkCache, min(int64(section.sectionIndex+1)*SectionSize, fileSize))
+	}
+	section.reader.fileSize = fileSize
+}
+
+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) DataStartOffset(group *ChunkGroup, offset int64, fileSize int64) int64 {
+	section.lock.Lock()
+	defer section.lock.Unlock()
+
+	section.setupForRead(group, fileSize)
+
+	for x := section.visibleIntervals.Front(); x != nil; x = x.Next {
+		visible := x.Value
+		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 x := section.visibleIntervals.Front(); x != nil; x = x.Next {
+		visible := x.Value
+		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
+}