seaweedfs/weed/filer/filechunks_read.go
2023-09-18 16:12:50 -07:00

123 lines
2.9 KiB
Go

package filer
import (
"container/list"
"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"golang.org/x/exp/slices"
)
func readResolvedChunks(chunks []*filer_pb.FileChunk, startOffset int64, stopOffset int64) (visibles *IntervalList[*VisibleInterval]) {
var points []*Point
for _, chunk := range chunks {
if chunk.IsChunkManifest {
println("This should not happen! A manifest chunk found:", chunk.GetFileIdString())
}
start, stop := max(chunk.Offset, startOffset), min(chunk.Offset+int64(chunk.Size), stopOffset)
if start >= stop {
continue
}
points = append(points, &Point{
x: chunk.Offset,
ts: chunk.ModifiedTsNs,
chunk: chunk,
isStart: true,
})
points = append(points, &Point{
x: chunk.Offset + int64(chunk.Size),
ts: chunk.ModifiedTsNs,
chunk: chunk,
isStart: false,
})
}
slices.SortFunc(points, func(a, b *Point) bool {
if a.x != b.x {
return a.x < b.x
}
if a.ts != b.ts {
return a.ts < b.ts
}
return !a.isStart
})
var prevX int64
queue := list.New() // points with higher ts are at the tail
visibles = NewIntervalList[*VisibleInterval]()
var prevPoint *Point
for _, point := range points {
if queue.Len() > 0 {
prevPoint = queue.Back().Value.(*Point)
} else {
prevPoint = nil
}
if point.isStart {
if prevPoint != nil {
if point.x != prevX && prevPoint.ts < point.ts {
addToVisibles(visibles, prevX, prevPoint, point)
prevX = point.x
}
}
// insert into queue
if prevPoint == nil || prevPoint.ts < point.ts {
queue.PushBack(point)
prevX = point.x
} else {
for e := queue.Front(); e != nil; e = e.Next() {
if e.Value.(*Point).ts > point.ts {
queue.InsertBefore(point, e)
break
}
}
}
} else {
isLast := true
for e := queue.Back(); e != nil; e = e.Prev() {
if e.Value.(*Point).ts == point.ts {
queue.Remove(e)
break
}
isLast = false
}
if isLast && prevPoint != nil {
addToVisibles(visibles, prevX, prevPoint, point)
prevX = point.x
}
}
}
return
}
func addToVisibles(visibles *IntervalList[*VisibleInterval], prevX int64, startPoint *Point, point *Point) {
if prevX < point.x {
chunk := startPoint.chunk
visible := &VisibleInterval{
start: prevX,
stop: point.x,
fileId: chunk.GetFileIdString(),
modifiedTsNs: chunk.ModifiedTsNs,
offsetInChunk: prevX - chunk.Offset,
chunkSize: chunk.Size,
cipherKey: chunk.CipherKey,
isGzipped: chunk.IsCompressed,
}
appendVisibleInterfal(visibles, visible)
}
}
func appendVisibleInterfal(visibles *IntervalList[*VisibleInterval], visible *VisibleInterval) {
visibles.AppendInterval(&Interval[*VisibleInterval]{
StartOffset: visible.start,
StopOffset: visible.stop,
TsNs: visible.modifiedTsNs,
Value: visible,
})
}
type Point struct {
x int64
ts int64
chunk *filer_pb.FileChunk
isStart bool
}