.

wcfs/δbtail.go

@@ -285,7 +285,10 @@ func (δBtail *ΔBtail) Tail() zodb.Tid { return δBtail.δZtail.Tail() }
 // path[0] signifies tree root.
 // All path elements must be Tree except last one which must be Bucket.
 //
-// δBtail will also track all keys corresponding to added bucket nodes.		XXX
+// Besides key (which might point to value or hole), δBtail will also track all
+// keys residing in tracked leaf nodes. In particular after request for KeyMax or
+// KeyMin to be tracked, δBtail will keep on tracking changes to maximum or
+// minimum keys correspondingly.
 //
 // XXX objects in path must be with .PJar().At() == .head
 // XXX path -> []oid ?

wcfs/δbtail_test.go

@@ -270,11 +270,12 @@ func (tg *AllStructsSrv) AllStructs(kv1, kv2 map[Key]string, maxdepth, maxsplit,
 }
 
 
-// RBucket represents Bucket node covering [lo, hi) key range in its Tree.
+// RBucket represents Bucket node covering [lo, hi_] key range in its Tree.
+// NOTE it is not [lo,hi) but [lo,hi_] instead to avoid overflow at KeyMax.
 type RBucket struct {
 	// XXX +oid, +parent (RTree)
-	lo, hi Key
-	kv     map[Key]string // bucket's k->v; values were ZBlk objects whose data is loaded instead.
+	lo, hi_ Key
+	kv      map[Key]string // bucket's k->v; values were ZBlk objects whose data is loaded instead.
 }
 
 // RBucketSet represents set of buckets covering whole [-∞,∞) range.
@@ -284,15 +285,15 @@ type RBucketSet []*RBucket // k↑
 // Get returns RBucket which covers key k.
 func (rbs RBucketSet) Get(k Key) *RBucket {
 	i := sort.Search(len(rbs), func(i int) bool {
-		return k < rbs[i].hi
+		return k <= rbs[i].hi_
 	})
 	if i == len(rbs) {
 		panicf("BUG: key %v not covered;  coverage: %s", k, rbs.coverage())
 	}
 
 	rb := rbs[i]
-	if !(rb.lo <= k && k < rb.hi) {
-		panicf("BUG: get(%v) -> [%v, %v);  coverage: %s", k, rb.lo, rb.hi, rbs.coverage())
+	if !(rb.lo <= k && k <= rb.hi_) {
+		panicf("BUG: get(%v) -> [%v, %v];  coverage: %s", k, rb.lo, rb.hi_, rbs.coverage())
 	}
 
 	return rb
@@ -308,7 +309,7 @@ func (rbs RBucketSet) coverage() string {
 		if s != "" {
 			s += " "
 		}
-		s += fmt.Sprintf("[%v, %v)", rb.lo, rb.hi)
+		s += fmt.Sprintf("[%v, %v]", rb.lo, rb.hi_)
 	}
 	return s
 }
@@ -345,7 +346,7 @@ func XGetTree(db *zodb.DB, at zodb.Tid, root zodb.Oid) RBucketSet {
 }
 
 // xwalkDFS walks ztree in depth-first order emitting bvisit callback on visited bucket nodes.
-func xwalkDFS(ctx context.Context, lo, hi Key, ztree *Tree, bvisit func(*RBucket)) {
+func xwalkDFS(ctx context.Context, lo, hi_ Key, ztree *Tree, bvisit func(*RBucket)) {
 	X := exc.Raiseif
 
 	err := ztree.PActivate(ctx); X(err)
@@ -357,12 +358,12 @@ func xwalkDFS(ctx context.Context, lo, hi Key, ztree *Tree, bvisit func(*RBucket
 	// [len(ev)].Key = +∞ ; should be assumed so
 	ev := ztree.Entryv()
 	for i := range ev {
-		xlo := lo;  if i   > 0       { xlo = ev[i].Key() }
-		xhi := hi;  if i+1 < len(ev) { xhi = ev[i+1].Key() }
+		xlo  := lo;  if i   > 0       { xlo  = ev[i].Key() }
+		xhi_ := hi_; if i+1 < len(ev) { xhi_ = ev[i+1].Key() - 1 }
 
 		tchild, ok := ev[i].Child().(*Tree)
 		if ok {
-			xwalkDFS(ctx, xlo, xhi, tchild, bvisit)
+			xwalkDFS(ctx, xlo, xhi_, tchild, bvisit)
 			continue
 		}
 
@@ -386,7 +387,7 @@ func xwalkDFS(ctx context.Context, lo, hi Key, ztree *Tree, bvisit func(*RBucket
 		}
 
 
-		bvisit(&RBucket{xlo, xhi, bkv})
+		bvisit(&RBucket{xlo, xhi_, bkv})
 	}
 }
 
@@ -459,10 +460,12 @@ func xverifyΔBTail(t *testing.T, subj string, db *zodb.DB, treeRoot zodb.Oid, a
 
 		k1 := k
 		k2 := k
+		/*
 		if k == kInf {		// XXX not needed? - kill?
 			k1 = maxk1
 			k2 = maxk2
 		}
+		*/
 
 		q1 := []Key{k1}
 		q2 := []Key{k2}