.

wcfs/δbtail.go

@@ -242,6 +242,8 @@ type nodeTrack struct {
 
 // δtrackIndex represents change to trackIndex.		XXX name
 //
+// XXX refer to trackIndex.ApplyΔ
+//
 // The result B of applying δ to A is:
 //
 //	B = A.xDifference(δ.Del).xUnion(δ.Add)		(*)
@@ -368,6 +370,11 @@ func (A trackIndex) DifferenceInplace(B trackIndex) {
 
 	δnchild := map[zodb.Oid]int{}
 
+	A.xDifferenceInplace(B, δnchild)
+	A.fixup(δnchild)
+}
+
+func (A trackIndex) xDifferenceInplace(B trackIndex, δnchild map[zodb.Oid]int) {
 	// remove B.leafs and thier parents
 	for oid, t2 := range B {
 		if t2.nchild != 0 {
@@ -386,18 +393,19 @@ func (A trackIndex) DifferenceInplace(B trackIndex) {
 			δnchild[t.parent] -= 1
 		}
 	}
+}
 
-/* XXX kill
-	// process adds
-	for oid, δt := range δ.Add {
+func (A trackIndex) xUnionInplace(B trackIndex, δnchild map[zodb.Oid]int) {
+	// process additions
+	for oid, t2 := range B {
 		t, already := A[oid]
 		if already {
 			if t.parent != zodb.InvalidOid {
 				δnchild[t.parent] -= 1
-				t.parent = δt.parent
+				t.parent = t2.parent
 			}
 		} else {
-			t = &nodeTrack{parent: δt.parent, nchild: 0}
+			t = &nodeTrack{parent: t2.parent, nchild: 0}
 			A[oid] = t
 		}
 
@@ -405,9 +413,11 @@ func (A trackIndex) DifferenceInplace(B trackIndex) {
 			δnchild[t.parent] += 1 // remeber to nchild++ in parent
 		}
 	}
-*/
+}
 
-	// perform scheduled δnchild adjustment
+// fixup performs scheduled δnchild adjustment.
+// XXX place
+func (A trackIndex) fixup(δnchild map[zodb.Oid]int) {
 	gcq := []zodb.Oid{}
 	for oid, δnc := range δnchild {
 		t := A[oid]	// XXX t can be nil -> XXX no must be there as A is connected
@@ -436,6 +446,10 @@ func (A trackIndex) UnionInplace(B trackIndex) {
 	B.verify()
 	defer A.verify()
 
+	δnchild := map[zodb.Oid]int{}
+	A.xUnionInplace(B, δnchild)
+	A.fixup(δnchild)
+/*
 	for oid, t2 := range B {
 		t, already := A[oid]
 		if !already {
@@ -460,6 +474,7 @@ func (A trackIndex) UnionInplace(B trackIndex) {
 			}
 		}
 	}
+*/
 }
 
 // ApplyΔ applies δ to trackIdx.	XXX
@@ -475,8 +490,12 @@ func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
 	δ.Add.verify()
 	defer tidx.verify()
 
-	tidx.DifferenceInplace(δ.Del)
-	tidx.UnionInplace(δ.Add)
+	δnchild := map[zodb.Oid]int{}
+
+	tidx.xDifferenceInplace(δ.Del, δnchild)
+	tidx.xUnionInplace(δ.Add, δnchild)
+
+	tidx.fixup(δnchild)
 }
 
 // treeSetKey represents ordered set of keys.