.

wcfs/internal/zdata/δftail.go

@@ -23,7 +23,7 @@ package zdata
 //
 // It translates ZODB object-level changes to information about which blocks of
 // which ZBigFile were modified, and provides service to query that information.
-// See ΔFtail class documentation for details.
+// See ΔFtail class documentation for usage details.
 //
 //
 // ΔFtail organization
@@ -96,7 +96,7 @@ type setOid = set.Oid
 // tracked, even if it was changed in δZ, is not guaranteed to be present in δF.
 //
 // After file epoch (file creation, deletion, or any other change to file
-// object) previous track requests for that file become forgotten and has no
+// object) previous track requests for that file become forgotten and have no
 // further effect.
 //
 // ΔFtail provides the following operations:
@@ -121,14 +121,15 @@ type setOid = set.Oid
 // See also zodb.ΔTail and xbtree.ΔBtail
 type ΔFtail struct {
 	// ΔFtail merges ΔBtail with history of ZBlk
-	δBtail  *xbtree.ΔBtail
-	fileIdx map[zodb.Oid]setOid      // tree-root -> {} ZBigFile<oid>  as of @head  XXX -> root2file ?
-	byFile  map[zodb.Oid]*_ΔFileTail // file -> vδf tail	XXX
+	δBtail      *xbtree.ΔBtail
+	byFile      map[zodb.Oid]*_ΔFileTail // file -> vδf tail
+	filesByRoot map[zodb.Oid]setOid      // tree-root -> {} ZBigFile<oid>    as of @head
 
 	// set of files, which are newly tracked and for which byFile[foid].vδE was not yet rebuilt
 	trackNew setOid // {}foid
 
-	trackSetZBlk  map[zodb.Oid]*zblkTrack // zblk -> {} root -> {}blk	as of @head
+	// set of tracked ZBlk objects reverse-mapped to trees and block numbers
+	trackSetZBlk  map[zodb.Oid]*zblkTrack // zblk -> {} root -> {}blk    as of @head
 }
 
 // _ΔFileTail represents tail of revisional changes to one file.
@@ -154,6 +155,7 @@ type zblkTrack struct {
 	inroot map[zodb.Oid]setI64  // {} root -> {}blk
 }
 
+
 // ΔF represents a change in files space.
 type ΔF struct {
 	Rev    zodb.Tid
@@ -168,6 +170,7 @@ type ΔFile struct {
 	Size   bool   // whether file size changed
 }
 
+
 // NewΔFtail creates new ΔFtail object.
 //
 // Initial tracked set is empty.
@@ -178,8 +181,8 @@ type ΔFile struct {
 func NewΔFtail(at0 zodb.Tid, db *zodb.DB) *ΔFtail {
 	return &ΔFtail{
 		δBtail:        xbtree.NewΔBtail(at0, db),
-		fileIdx:       map[zodb.Oid]setOid{},
 		byFile:        map[zodb.Oid]*_ΔFileTail{},
+		filesByRoot:   map[zodb.Oid]setOid{},
 		trackNew:      setOid{},
 		trackSetZBlk:  map[zodb.Oid]*zblkTrack{},
 	}
@@ -226,10 +229,10 @@ func (δFtail *ΔFtail) Track(file *ZBigFile, blk int64, path []btree.LONode, zb
 
 	rootObj := path[0].(*btree.LOBTree)
 	root    := rootObj.POid()
-	files, ok := δFtail.fileIdx[root]
+	files, ok := δFtail.filesByRoot[root]
 	if !ok {
 		files = setOid{}
-		δFtail.fileIdx[root] = files
+		δFtail.filesByRoot[root] = files
 	}
 	files.Add(foid)
 
@@ -420,7 +423,7 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit) (_ ΔF, err error) {
 	//fmt.Printf("δB.ΔByRoot: %v\n", δB.ΔByRoot)
 	for root, δt := range δB.ΔByRoot {
 		//fmt.Printf("root: %v   δt: %v\n", root, δt)
-		files := δFtail.fileIdx[root]
+		files := δFtail.filesByRoot[root]
 		// NOTE files might be empty e.g. if a zfile was tracked, then
 		// deleted, but the tree referenced by zfile.blktab is still
 		// not-deleted, remains tracked and is changed.
@@ -484,7 +487,7 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit) (_ ΔF, err error) {
 				continue
 			}
 			//fmt.Printf("root: %v   inblk: %v\n", root, inblk)
-			files := δFtail.fileIdx[root]
+			files := δFtail.filesByRoot[root]
 			for file := range files {
 				δfile, ok := δF.ByFile[file]
 				if !ok {
@@ -510,21 +513,21 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit) (_ ΔF, err error) {
 
 		//fmt.Printf("δZBigFile: %v\n", δ)
 
-		// update .fileIdx
+		// update .filesByRoot
 		if δ.blktabOld != xbtree.VDEL {
-			files, ok := δFtail.fileIdx[δ.blktabOld]
+			files, ok := δFtail.filesByRoot[δ.blktabOld]
 			if ok {
 				files.Del(foid)
 				if len(files) == 0 {
-					delete(δFtail.fileIdx, δ.blktabOld)
+					delete(δFtail.filesByRoot, δ.blktabOld)
 				}
 			}
 		}
 		if δ.blktabNew != xbtree.VDEL {
-			files, ok := δFtail.fileIdx[δ.blktabNew]
+			files, ok := δFtail.filesByRoot[δ.blktabNew]
 			if !ok {
 				files = setOid{}
-				δFtail.fileIdx[δ.blktabNew] = files
+				δFtail.filesByRoot[δ.blktabNew] = files
 			}
 			files.Add(foid)
 		}

wcfs/internal/zdata/δftail_test.go

@@ -485,14 +485,14 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 			vδE = vδE[icut:]
 		}
 
-		// verify δFtail.fileIdx
-		fileIdxOK := map[zodb.Oid]setOid{}
+		// verify δFtail.filesByRoot
+		filesByRootOK := map[zodb.Oid]setOid{}
 		if !delfile {
 			__ := setOid{}; __.Add(foid)
-			fileIdxOK[t.Root()] = __
+			filesByRootOK[t.Root()] = __
 		}
-		if !reflect.DeepEqual(δFtail.fileIdx, fileIdxOK) {
-			t.Errorf("fileIdx:\nhave: %v\nwant: %v", δFtail.fileIdx, fileIdxOK)
+		if !reflect.DeepEqual(δFtail.filesByRoot, filesByRootOK) {
+			t.Errorf("filesByRoot:\nhave: %v\nwant: %v", δFtail.filesByRoot, filesByRootOK)
 		}
 
 		// verify δftail.root