.

wcfs/internal/xbtree/δbtail.go

@@ -210,7 +210,7 @@ func (δB *ΔTail) update() {
 /*
 	δbZ = {}
 	for δ in δZ:
-		.rootIdx[δ]:
+		.trackIdx[δ]:
 			ø	-> nothing
 			root	-> δbZ[root] += δ
 

wcfs/misc.go

@@ -676,6 +676,16 @@ type ΔFTail struct {
 	fileIdx map[*btree.LOBTree]SetBigFile	// root -> {} BigFile	XXX root -> oid?
 }
 
+type ΔFentry struct {
+	Rev     zodb.Tid
+	Changev []ΔFile
+}
+
+type ΔFile struct {
+	File *BigFile
+	Blkv []int64
+}
+
 func NewΔFTail(at0 zodb.Tid) *ΔFTail {
 	return &ΔFTail{
 		ΔTail:   xbtree.NewΔTail(at0),
@@ -694,6 +704,29 @@ func (δf *ΔFTail) Track(file *BigFile, path []btree.LONode) {
 	files.Add(file)
 }
 
+func (δf *ΔFTail) Update(δZ *zodb.EventCommit) ΔFentry {
+	δf.ΔTail.Update(δZ)
+	δB := xbtree.ΔRevEntry{} // XXX stub
+	var changev []ΔFile // δB.Changev root -> file (via .fileIdx)
+	for _, δ := range δB.Changev {
+		files := δf.fileIdx[δ.Root]
+		if len(files) == 0 {
+			panic(fmt.Sprintf("ΔFTail: root<%s> -> ø file", δ.Root.POid()))
+		}
+		for file := range files {
+			changev = append(changev, ΔFile{
+				File: file,
+				Blkv: δ.Keyv,
+			})
+		}
+	}
+
+	return ΔFentry{
+		Rev:     δB.Rev,
+		Changev: changev,
+	}
+}
+
 
 // ---- make df happy (else it complains "function not supported") ----