.

wcfs/δbtail.go

@@ -210,20 +210,17 @@ type δtrackIndex struct {
 	Add trackIndex
 }
 
-// ApplyΔ applies δ to trackIdx.	XXX
-func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
-	fmt.Printf("\n\nApplyΔ\n")
-	fmt.Printf("\tDelLeaf: %v\n", δ.DelLeaf)
-	fmt.Printf("\tAdd:     %v\n", δ.Add)
-
-	// remove leafs and thier parents
-	for leaf := range δ.DelLeaf {
-		t, present := tidx[leaf]
+// gc1 garbage-collects oid and cleans up its parent down-up.
+func (tidx trackIndex) gc1(oid zodb.Oid) {
+	t, present := tidx[oid]
 	if !present {
-			continue // leaf already not there
+		return // already not there
+	}
+	if t.nchild != 0 {
+		panicf("gc %v  (nchild != 0)", t)
 	}
 
-		delete(tidx, leaf)
+	delete(tidx, oid)
 	parent := t.parent
 	for parent != zodb.InvalidOid {
 		t := tidx[parent]
@@ -234,6 +231,17 @@ func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
 		delete(tidx, parent)
 		parent = t.parent
 	}
+}
+
+// ApplyΔ applies δ to trackIdx.	XXX
+func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
+	fmt.Printf("\n\nApplyΔ\n")
+	fmt.Printf("\tDelLeaf: %v\n", δ.DelLeaf)
+	fmt.Printf("\tAdd:     %v\n", δ.Add)
+
+	// remove leafs and thier parents
+	for leaf := range δ.DelLeaf {
+		tidx.gc1(leaf)
 	}
 
 	// process adds
@@ -254,9 +262,16 @@ func (tidx trackIndex) ApplyΔ(δ *δtrackIndex) {
 			δnchild[t.parent] += 1 // remeber to nchild++ in parent
 		}
 	}
+	gcq := []zodb.Oid{}
 	for parent, δnc := range δnchild {
-		tidx[parent].nchild += δnc
-		// XXX .nchild == 0 - remove ?
+		t := tidx[parent]
+		t.nchild += δnc
+		if t.nchild == 0 {
+			gcq = append(gcq, t.parent)
+		}
+	}
+	for _, oid := range gcq {
+		tidx.gc1(oid)
 	}
 }