.

wcfs/δbtail.go

@@ -99,8 +99,8 @@ type ΔBtail struct {
 	trackNew map[zodb.Oid]struct{}	// XXX SetOid
 }
 
-// Δ represents a change in BTrees space.
-type Δ struct {
+// ΔB represents a change in BTrees space.
+type ΔB struct {
 	Rev	zodb.Tid
 	Change	map[*Tree]map[Key]Value // {} root -> {}(key, value)
 }
@@ -206,7 +206,7 @@ func (δBtail *ΔBtail) Track(path []Node) {	// XXX Tree|Bucket; path[0] = root
 // only those keys, that correspond to tracked subset of δZ.
 //
 // δZ should include all objects changed by ZODB transaction.
-func (δBtail *ΔBtail) Update(δZ *zodb.EventCommit) Δ {
+func (δBtail *ΔBtail) Update(δZ *zodb.EventCommit) ΔB {
 	δBtail.δZtail.Append(δZ.Tid, δZ.Changev)
 
 	// {} root -> []oid changed under that root
@@ -221,7 +221,7 @@ func (δBtail *ΔBtail) Update(δZ *zodb.EventCommit) Δ {
 		}
 	}
 
-	δB := Δ{Rev: δZ.Tid, Change: make(map[*Tree]map[Key]Value)}
+	δB := ΔB{Rev: δZ.Tid, Change: make(map[*Tree]map[Key]Value)}
 
 	if len(δZByRoot) == 0 {
 		return δB // tracked set not changed
@@ -335,10 +335,17 @@ func (δΒtail *ΔBtail) Get(ctx context.Context, root *Tree, key Key, at zodb.T
 	return
 }
 
-// XXX SliceByRev
+// XXX
+func (δBtail *ΔBtail) SliceByRev(lo, hi zodb.Tid) /*readonly*/ []ΔB {
+	δassertSlice(δBtail, lo, hi)
+
+	panic("TODO")
+}
 
 // XXX
 func (δBtail *ΔBtail) SliceByRootRev(root *Tree, lo, hi zodb.Tid) /*readonly*/[]ΔTree {
+	δassertSlice(δBtail, lo, hi)
+
 	panic("TODO")
 }
 
@@ -388,3 +395,15 @@ func (δBtail *ΔBtail) SliceByRootRev(root *Tree, lo, hi zodb.Tid) /*readonly*/
 //
 // . -k(blk) -> invalidate #blk
 // . +k(blk) -> invalidate #blk (e.g. if blk was previously read as hole)
+
+
+// misc
+
+// δassertSlice asserts that δ.tail ≤ lo ≤ hi ≤ δ.head
+func δassertSlice(δ interface { Head() zodb.Tid; Tail() zodb.Tid }, lo, hi zodb.Tid) {
+	tail := δ.Tail()
+	head := δ.Head()
+	if !(tail <= lo && lo <= hi && hi <= head) {
+		panicf("invalid slice: (%s, %s];  (tail, head] = (%s, %s]", lo, hi, tail, head)
+	}
+}

wcfs/δftail.go

@@ -155,15 +155,16 @@ func (δFtail *ΔFtail) ForgetPast(revCut zodb.Tid) {
 	panic("TODO")
 }
 
-// XXX SliceByRev
+// XXX
+func (δFtail *ΔFtail) SliceByRev(lo, hi zodb.Tid) /*readonly*/ []ΔF {
+	δassertSlice(δFtail, lo, hi)
 
-// XXX SliceByFileRev
+	panic("TODO")
+}
+
+// XXX
 func (δFtail *ΔFtail) SliceByFileRev(f *BigFile, lo, hi zodb.Tid) /*readonly*/[]Δfile {
-        tail := δFtail.Tail()
-        head := δFtail.Head()
-        if !(tail <= lo && lo <= hi && hi <= head) {
-                panicf("δFtail.SliceByFileRev: invalid query: (%s, %s];  (tail, head] = (%s, %s]", lo, hi, tail, head)
-        }
+	δassertSlice(δFtail, lo, hi)
 
 	// XXX activate zfile?
 	vδT := δFtail.δBtail.SliceByRootRev(f.zfile.blktab, lo, hi)