.

wcfs/pptreesubset.go

@@ -26,6 +26,7 @@ import (
 	"lab.nexedi.com/kirr/neo/go/zodb"
 )
 
+const debugPPSet = false
 
 // PPTreeSubSet repesents PP-connected subset of tree node objects.
 //
@@ -55,66 +56,6 @@ type nodeInTree struct {
 	// XXX + [lo,hi) range this node is coming under in its parent
 }
 
-// ΔPPTreeSubSet represents a change to PPTreeSubSet.
-//
-// It can be applied via PPTreeSubSet.ApplyΔ .
-//
-// The result B of applying δ to A is:
-//
-//	B = A.xDifference(δ.Del).xUnion(δ.Add)		(*)
-//
-// (*) NOTE δ.Del and δ.Add might have their leafs starting from non-leaf nodes in A/B.
-//     This situation arises when δ represents a change in path to particular
-//     node, but that node itself does not change, for example:
-//
-//            c*             c
-//           / \            /
-//         41*  42         41
-//          |    |         | \
-//         22   43        46  43
-//               |         |   |
-//              44        22  44
-//
-//     Here nodes {c, 41} are changed, node 42 is unlinked, and node 46 is added.
-//     Nodes 43 and 44 stay unchanged.
-//
-//         δ.Del = c-42-43   | c-41-22
-//         δ.Add = c-41-43   | c-41-46-22
-//
-//     The second component with "-22" builds from leaf, but the first
-//     component with "-43" builds from non-leaf node.
-//
-//         δnchildNonLeafs = {43: +1}
-//
-//     Only complete result of applying all
-//
-//         - xfixup(-1, δnchildNonLeafs)
-//         - δ.Del,
-//         - δ.Add, and
-//         - xfixup(+1, δnchildNonLeafs)
-//
-//     produce correctly PP-connected set.
-type ΔPPTreeSubSet struct {
-	Del PPTreeSubSet
-	Add PPTreeSubSet
-	δnchildNonLeafs map[zodb.Oid]int
-}
-
-// Update updates δ to be combination of δ+δ2.
-func (δ *ΔPPTreeSubSet) Update(δ2 *ΔPPTreeSubSet) {
-	δ.Del.UnionInplace(δ2.Del)
-	δ.Add.UnionInplace(δ2.Add)
-	for oid, δnc := range δ2.δnchildNonLeafs {
-		δ.δnchildNonLeafs[oid] += δnc
-	}
-}
-
-// Reverse changes δ=diff(A->B) to δ'=diff(A<-B).
-func (δ *ΔPPTreeSubSet) Reverse() {
-	δ.Del, δ.Add = δ.Add, δ.Del
-	// δnchildNonLeafs stays the same
-}
-
 
 // verify checks internal consistency of S.
 func (S PPTreeSubSet) verify() {
@@ -316,29 +257,6 @@ func (A PPTreeSubSet) UnionInplace(B PPTreeSubSet) {
 	A.xUnionInplace(B)
 }
 
-// ApplyΔ applies δ to S.
-//
-// See ΔPPTreeSubSet documentation for details.
-func (S PPTreeSubSet) ApplyΔ(δ *ΔPPTreeSubSet) {
-	if debugPPSet {
-		fmt.Printf("\n\nApplyΔ\n")
-		fmt.Printf("  A: %s\n", S)
-		fmt.Printf("  -: %s\n", δ.Del)
-		fmt.Printf("  +: %s\n", δ.Add)
-		fmt.Printf("  x: %v\n", δ.δnchildNonLeafs)
-		defer fmt.Printf("\n->B: %s\n", S)
-	}
-
-	S.verify()
-	δ.Del.verify()
-	δ.Add.verify()
-	defer S.verify()
-
-	S.xfixup(-1, δ.δnchildNonLeafs)
-	S.xDifferenceInplace(δ.Del)
-	S.xUnionInplace(δ.Add)
-	S.xfixup(+1, δ.δnchildNonLeafs)
-}
 
 // Path returns path leading to node specified by oid.
 //
@@ -461,4 +379,91 @@ func (t nodeInTree) String() string {
 	return fmt.Sprintf("{p%s c%d}", t.parent, t.nchild)
 }
 
-const debugPPSet = false
+
+
+// ---- diff/patch ----
+
+// ΔPPTreeSubSet represents a change to PPTreeSubSet.
+//
+// It can be applied via PPTreeSubSet.ApplyΔ .
+//
+// The result B of applying δ to A is:
+//
+//	B = A.xDifference(δ.Del).xUnion(δ.Add)		(*)
+//
+// (*) NOTE δ.Del and δ.Add might have their leafs starting from non-leaf nodes in A/B.
+//     This situation arises when δ represents a change in path to particular
+//     node, but that node itself does not change, for example:
+//
+//            c*             c
+//           / \            /
+//         41*  42         41
+//          |    |         | \
+//         22   43        46  43
+//               |         |   |
+//              44        22  44
+//
+//     Here nodes {c, 41} are changed, node 42 is unlinked, and node 46 is added.
+//     Nodes 43 and 44 stay unchanged.
+//
+//         δ.Del = c-42-43   | c-41-22
+//         δ.Add = c-41-43   | c-41-46-22
+//
+//     The second component with "-22" builds from leaf, but the first
+//     component with "-43" builds from non-leaf node.
+//
+//         δnchildNonLeafs = {43: +1}
+//
+//     Only complete result of applying all
+//
+//         - xfixup(-1, δnchildNonLeafs)
+//         - δ.Del,
+//         - δ.Add, and
+//         - xfixup(+1, δnchildNonLeafs)
+//
+//     produce correctly PP-connected set.
+type ΔPPTreeSubSet struct {
+	Del PPTreeSubSet
+	Add PPTreeSubSet
+	δnchildNonLeafs map[zodb.Oid]int
+}
+
+// Update updates δ to be combination of δ+δ2.
+func (δ *ΔPPTreeSubSet) Update(δ2 *ΔPPTreeSubSet) {
+	δ.Del.UnionInplace(δ2.Del)
+	δ.Add.UnionInplace(δ2.Add)
+	for oid, δnc := range δ2.δnchildNonLeafs {
+		δ.δnchildNonLeafs[oid] += δnc
+	}
+}
+
+// Reverse changes δ=diff(A->B) to δ'=diff(A<-B).
+func (δ *ΔPPTreeSubSet) Reverse() {
+	δ.Del, δ.Add = δ.Add, δ.Del
+	// δnchildNonLeafs stays the same
+}
+
+
+// ApplyΔ applies δ to S.
+//
+// See ΔPPTreeSubSet documentation for details.
+func (S PPTreeSubSet) ApplyΔ(δ *ΔPPTreeSubSet) {
+	if debugPPSet {
+		fmt.Printf("\n\nApplyΔ\n")
+		fmt.Printf("  A: %s\n", S)
+		fmt.Printf("  -: %s\n", δ.Del)
+		fmt.Printf("  +: %s\n", δ.Add)
+		fmt.Printf("  x: %v\n", δ.δnchildNonLeafs)
+		defer fmt.Printf("\n->B: %s\n", S)
+	}
+
+	S.verify()
+	δ.Del.verify()
+	δ.Add.verify()
+	defer S.verify()
+
+	S.xfixup(-1, δ.δnchildNonLeafs)
+	S.xDifferenceInplace(δ.Del)
+	S.xUnionInplace(δ.Add)
+	S.xfixup(+1, δ.δnchildNonLeafs)
+}