.

wcfs/δbtail.go

@@ -221,31 +221,42 @@ func (tidx trackIndex) gc1(oid zodb.Oid) {
 	}
 
 	delete(tidx, oid)
-	parent := t.parent
-	for parent != zodb.InvalidOid {
-		t := tidx[parent]
+	oid = t.parent
+	for oid != zodb.InvalidOid {
+		t := tidx[oid]
 		t.nchild--
-		if t.nchild > 0 {
+		if t.nchild > 0 || /* root node */t.parent == zodb.InvalidOid {
 			break
 		}
-		delete(tidx, parent)
-		parent = t.parent
+		delete(tidx, oid)
+		oid = t.parent
 	}
 }
 
 // ApplyΔ applies δ to trackIdx.	XXX
 func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
 	//fmt.Printf("\n\nApplyΔ\n")
+	//fmt.Printf("\ttidx:    %v\n", tidx)
 	//fmt.Printf("\tDelLeaf: %v\n", δ.DelLeaf)
 	//fmt.Printf("\tAdd:     %v\n", δ.Add)
+	//defer fmt.Printf("\n\t-> tidx: %v\n", tidx)
+
+	δnchild := map[zodb.Oid]int{}
 
 	// remove leafs and thier parents
 	for leaf := range δ.DelLeaf {
-		tidx.gc1(leaf)
+		t, present := tidx[leaf]
+		if !present {
+			continue // already not there
+		}
+
+		delete(tidx, leaf)
+		if t.parent != zodb.InvalidOid {
+			δnchild[t.parent] -= 1
+		}
 	}
 
 	// process adds
-	δnchild := map[zodb.Oid]int{}
 	for oid, δt := range δ.Add {
 		t, already := tidx[oid]
 		if already {
@@ -262,14 +273,18 @@ func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
 			δnchild[t.parent] += 1 // remeber to nchild++ in parent
 		}
 	}
+
+	// perform scheduled δnchild adjustment
 	gcq := []zodb.Oid{}
 	for oid, δnc := range δnchild {
-		t := tidx[oid]
+		t := tidx[oid]	// XXX t can be nil -> XXX no must be there as tidx is connected
 		t.nchild += δnc
-		if t.nchild == 0 {
+		if t.nchild == 0 && /* not root node */t.parent != zodb.InvalidOid {
 			gcq = append(gcq, oid)
 		}
 	}
+
+	// GC parents that became to have .nchild == 0
 	for _, oid := range gcq {
 		tidx.gc1(oid)
 	}
@@ -842,10 +857,15 @@ func treediff(ctx context.Context, root zodb.Oid, δtops SetOid, δZTC SetOid, t
 		}
 	}
 
-	// adjust trackIdx
-	for _, δtrack := range δtrackv {
-		trackIdx.ApplyΔ(δtrack)
+	// adjust trackIdx by merge(δtrackTops)
+	δtrack := &δtrackIndex{DelLeaf: SetOid{}, Add: trackIndex{}}
+	for _, δ := range δtrackv {
+		δtrack.DelLeaf.Update(δ.DelLeaf)
+		for oid, t := range δ.Add {
+			δtrack.Add[oid] = t // XXX verify changes from 2 δtrackTops are consistent
 		}
+	}
+	trackIdx.ApplyΔ(δtrack)
 
 	return δT, nil
 }
@@ -1504,7 +1524,7 @@ func pop(nodeStk *[]*nodeInRange) *nodeInRange {
 }
 
 
-const debug = true
+const debug = false
 func tracef(format string, argv ...interface{}) {
 	if debug {
 		fmt.Printf(format, argv...)