.

wcfs/δbtail.go

@@ -797,7 +797,7 @@ func diffT(ctx context.Context, a, b *Tree, δZTC SetOid, trackIdx map[zodb.Oid]
 	tracef("  av: %s\n", av)
 	tracef("  bv: %s\n", bv)
 
-	// phase 2: iterate through keys queued for A and B, delve into
+	// XXX phase 2: iterate through keys queued for A and B, delve into
 	// corresponding nodes, and merge diff generated from them into δ.
 	// Each delve for A or B, potentially adds new keys to process on the
 	// other side.
@@ -813,8 +813,91 @@ func diffT(ctx context.Context, a, b *Tree, δZTC SetOid, trackIdx map[zodb.Oid]
 		// A queue
 //		Bqueue = SetKey{}
 		for len(Aqueue) > 0 {
-			Xa := pop(&Aqueue)
-			tracef("  A %v\n", Xa)
+			anode := pop(&Aqueue)
+			tracef("  A %v\n", anode)
+
+			// anode is a node from A.
+			// it can potentially contribute to -δA if
+			// - Xa ∈ Tracked  ∈ δZTC
+			// - Xa ∈ Tracked _and_ is no longer referenced
+
+			interesting := false
+			if δZTC.Has(anode.node.POid()) {
+				interesting = true
+			}
+			// XXX "no longer referenced"
+			if !interesting {
+				continue
+			}
+
+			// anode can potentially contribute to -δA
+			// - tree:   expand and queue its children
+			// - bucket: -δA += anode
+			switch node := anode.node.(type) {
+			case *Tree:
+				err = node.PActivate(ctx);  if err != nil { return nil, err }
+				defer node.PDeactivate()
+
+				// empty tree - do not expand into bucket - only process tracked holes
+				if len(node.Entryv()) == 0 {
+					// XXX dup wrt bucket processing?
+					δA := map[Key]ΔValue{}
+					track, ok := trackIdx[node.POid()]
+					if !ok {
+						panicf("%s ∈ δZTC, but ∉ trackIdx", vnode(node))
+					}
+					for k := range track.holes {
+						δA[k] = ΔValue{VDEL, VDEL} // ø->ø indicates hole
+					}
+					// δ <- δA
+					err = δMerge(δ, δA)
+					if err != nil {
+						return nil, err
+					}
+
+				/*
+					// Adone  <- δA
+					// Bqueue <- δA
+					for k := range δA {
+						Adone.Add(k)
+						Bqueue.Add(k)
+					}
+				*/
+
+					anode.done = true
+					continue
+				}
+
+				av.Expand(anode)
+
+			case *Bucket:
+				δA, err := diffB(ctx, node, nil)
+				if err != nil {
+					return nil, err
+				}
+				// XXX also extract holes
+
+				// δ <- δA
+				err = δMerge(δ, δA)
+				if err != nil {
+					return nil, err
+				}
+
+				/*
+				// Adone  <- δA
+				// Bqueue <- δA
+				for k_ := range δA {
+					Adone.Add(k_)
+					if !Bdone.Has(k_) {
+						Bqueue.Add(k_)
+					}
+				}
+				*/
+
+				anode.done = true
+			}
+
+
 
 /*
 			anode, ok, err := av.GetToLeaf(ctx, k)