.

wcfs/δbtail.go

@@ -214,8 +214,42 @@ type δtrackIndex struct {
 //	panic("TODO")
 //}
 
-func (tidx trackIndex) ApplyΔ(δtidx *δtrackIndex) {
-	panic("TODO")
+// ApplyΔ applies δ to trackIdx.	XXX
+func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
+	// remove leafs and thier parents
+	for leaf := range δ.DelLeaf {
+		t, present := tidx[leaf]
+		if !present {
+			continue // leaf already not there
+		}
+
+		delete(tidx, leaf)
+		parent := t.parent
+		for parent != zodb.InvalidOid {
+			t := tidx[parent]
+			t.nchild--
+			if t.nchild > 0 {
+				break
+			}
+			delete(tidx, parent)
+			parent = t.parent
+		}
+	}
+
+	// process adds
+	δnchild := map[zodb.Oid]int{}
+	for oid, δt := range δ.Add {
+		_, already := tidx[oid]
+		if already {
+			continue // object already tracked
+		}
+
+		tidx[oid] = &nodeTrack{parent: δt.parent, nchild: 0}
+		δnchild[δt.parent] += 1 // remeber to nchild++ in parent
+	}
+	for parent, δnc := range δnchild {
+		tidx[parent].nchild += δnc
+	}
 }
 
 // treeSetKey represents ordered set of keys.
@@ -803,8 +837,12 @@ func diffX(ctx context.Context, a, b Node, δZTC SetOid, trackIdx trackIndex, ho
 	if isT {
 		return diffT(ctx, aT, bT, δZTC, trackIdx, holeIdx)
 	} else {
+		var δtrack *δtrackIndex
 		δ, err := diffB(ctx, aB, bB)
-		return δ, /*δtrack*/nil, err	// XXX ok?
+		if δ != nil {
+			δtrack = &δtrackIndex{}
+		}
+		return δ, δtrack, err
 	}
 }
 
@@ -823,6 +861,7 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackIdx trackIndex, h
 	if B == nil { panic("B is nil") }
 
 	δ = map[Key]ΔValue{}
+	δtrack = &δtrackIndex{DelLeaf: SetOid{}, Add: trackIndex{}}
 	defer tracef("  -> δ: %v\n", δ)
 
 	// initial split ranges for A and B