.

wcfs/wcfs.go

@@ -616,6 +616,7 @@ type BigFile struct {
 //	δtail *ΔTailI64 // [](rev↑, []#blk)
 
 	// blocks that were ever read-accessed (head/ only)	XXX locking by bfdir.δFmu ?
+	// XXX = δFtail.Tracked(f) ?
 	accessed SetI64
 
 	// inflight loadings of ZBigFile from ZODB.
@@ -1275,9 +1276,9 @@ func (f *BigFile) readBlk(ctx context.Context, blk int64, dest []byte) (err erro
 	// into missing both kernel pagecache (if not yet updated) and empty .loading[blk],
 	// and thus would trigger DB access again.
 	//
-	// XXX if direct-io: don't touch pagecache
-	// XXX upload parts only not covered by currrent read (not to e.g. wait for page lock)
-	// XXX skip upload completely if read is wide to cover whole blksize
+	// TODO if direct-io: don't touch pagecache
+	// TODO upload parts only not covered by currrent read (not to e.g. wait for page lock)
+	// TODO skip upload completely if read is wide to cover whole blksize
 	go f.uploadBlk(blk, loading)
 
 	return nil

wcfs/δbtail.go

@@ -165,7 +165,7 @@ type ΔBtail struct {
 	δZtail *zodb.ΔTail
 
 	// XXX vvv keys ∈ tracked -> keys ∈ kadj[tracked] ?
-//	δRtail []ΔRoots // which BTree were changed; Noted only by keys ∈ tracked subset
+//	vδB []ΔB // data with δB changes; Noted only by keys ∈ tracked subset
 	byRoot map[zodb.Oid]*ΔTtail // {} root -> [] k/v change history; only for keys ∈ tracked subset
 
 	// handle to make connections to access database.
@@ -184,6 +184,34 @@ type ΔBtail struct {
 //	trackNew SetOid
 }
 
+
+// ΔB represents a change in BTrees space.
+type ΔB struct {
+	Rev    zodb.Tid
+	ByRoot map[zodb.Oid]map[Key]ΔValue // {} root -> {}(key, δvalue)
+}
+
+// ΔTtail represent tail of revisional changes to one BTree.
+//
+// See ΔBtail documentation for details.
+type ΔTtail struct {
+	vδT []ΔTree // changes to tree keys; rev↑. covers keys ∈ tracked subset
+
+	// {}k/v @tail for keys that are changed in (tail, head].
+	KVAtTail map[Key]Value		// XXX not needed since vδT has ΔValue ?
+
+	// index for LastRevOf queries
+	lastRevOf map[Key]zodb.Tid // {} key -> last
+}
+
+// ΔTree describes changes to one BTree in one revision.
+// XXX -> ΔT ?
+type ΔTree struct {
+	Rev  zodb.Tid
+	KV   map[Key]Value	// XXX Value -> ΔValue ?
+}
+
+
 // XXX place
 type trackIndex map[zodb.Oid]*nodeTrack
 
@@ -309,40 +337,6 @@ func (hi treeSetKey) GetInRange(lo, hi_ Key) SetKey {
 	return ret
 }
 
-// ΔB represents a change in BTrees space.
-type ΔB struct {
-	Rev	zodb.Tid
-	ByRoot	map[zodb.Oid]map[Key]ΔValue // {} root -> {}(key, δvalue)
-}
-
-/*
-// ΔRoots describes which BTrees were change in one revision.
-type ΔRoots struct {
-	Rev   zodb.Tid
-	Roots []*Tree	// root XXX -> Oid?	XXX -> SetTree?
-}
-*/
-
-// ΔTtail represent tail of revisional changes to one BTree.
-//
-// See ΔBtail documentation for details.
-type ΔTtail struct {
-	vδT []ΔTree // changes to tree keys; rev↑. covers keys ∈ tracked subset
-
-	// {}k/v @tail for keys that are changed in (tail, head].
-	KVAtTail map[Key]Value		// XXX not needed since vδT has ΔValue ?
-
-	// index for LastRevOf queries
-	lastRevOf map[Key]zodb.Tid // {} key -> last
-}
-
-// ΔTree describes changes to one BTree in one revision.
-// XXX -> ΔT ?
-type ΔTree struct {
-	Rev  zodb.Tid
-	KV   map[Key]Value	// XXX Value -> ΔValue ?
-}
-
 // NewΔBtail creates new empty ΔBtail object.
 //
 // Initial tracked set is empty.
@@ -1348,13 +1342,16 @@ func (δBtail *ΔBtail) ForgetPast(revCut zodb.Tid) {
 // entries in .δZtail into account.
 // func (δBtail *ΔBtail) update()
 
+
 // Get returns root[key] as of @at database state plus revision that changed it.
 //
 // if revExact=False - rev is upper estimate for the revision.
 //
 // XXX at must ∈ (tail, head]	XXX [tail ?
 // XXX key must be tracked
-func (δΒtail *ΔBtail) Get(ctx context.Context, root *Tree, key Key, at zodb.Tid) (value Value, ok bool, rev zodb.Tid, revExact bool, err error) {
+//
+// XXX naming -> GetAt ?
+func (δBtail *ΔBtail) Get(ctx context.Context, root *Tree, key Key, at zodb.Tid) (value Value, ok bool, rev zodb.Tid, revExact bool, err error) {
 	defer xerr.Contextf(&err, "δBtail: root<%s>: get %d @%s", root.POid(), key, at)
 	// XXX key not tracked		-> panic
 	// XXX at not ∈ (tail, head]	-> panic
@@ -1367,7 +1364,7 @@ func (δΒtail *ΔBtail) Get(ctx context.Context, root *Tree, key Key, at zodb.T
 	// XXX dirty -> rebuild
 
 	// XXX -> index lastXXXOf(key) | linear scan ↓ looking for change <= at
-	δTtail := δΒtail.byRoot[root.POid()]
+	δTtail := δBtail.byRoot[root.POid()]
 	if δTtail == nil {
 		panicf("δBtail: root<%s> not tracked", root.POid())
 	}
@@ -1391,13 +1388,15 @@ func (δΒtail *ΔBtail) Get(ctx context.Context, root *Tree, key Key, at zodb.T
 	}
 
 	// key not in history tail.
-	// either use @tail[key], if it is present, or @head[key]
-	rev = δΒtail.Tail()
+	// either use @tail[key], if it is present, or @head[key]	FIXME tail[key] must be present
+	rev = δBtail.Tail()
 	revExact = false
 	value, ok = δTtail.KVAtTail[key]
 	if ok {
 		return
 	}
+
+	// FIXME this should go away (tail[key] must be present)
 	// @tail[key] is not present - key was not changing in (tail, head].
 	// since at ∈ (tail, head] we can use @head[key] as the result
 	xvalue, ok, err := root.Get(ctx, key)

wcfs/δbtail_test.go

@@ -853,6 +853,8 @@ func testΔBTail(t *testing.T, testq chan ΔBTestEntry) {
 		tracef("\n\n\n**** %s ****\n\n", subj)
 		xverifyΔBTail(t, subj, db, tg.treeRoot, at1,at2, xkv1,xkv2, δZ, test.kadjOK)
 
+		// XXX also verify ΔBtail.Get + ...
+
 		at1   = at2
 		xkv1  = xkv2
 		tree1 = tree2

wcfs/δftail.go

@@ -476,7 +476,7 @@ func (δFtail *ΔFtail) LastBlkRev(ctx context.Context, f *BigFile, blk int64, a
 	// XXX activate zfile?
 	zblkOid, ok, tabRev, tabRevExact, err := δFtail.δBtail.Get(ctx, f.zfile.blktab, blk, at)
 	if err != nil {
-		panic(err)
+		panic(err) // XXX
 	}
 
 	// block was removed