.

wcfs/wcfs.go

@@ -122,7 +122,6 @@
 // clients, that had requested it (separately to each client), about the
 // changes:
 //
-//						XXX rev_max -> rev?
 //	S: 2 pin <bigfileX> #<blk> @<rev_max>	XXX 2-> 2*k (multiple pins in parallel)
 //
 // and waits until all clients confirm that changed file block can be updated
@@ -291,7 +290,7 @@ package main
 //	  cache for @<rev>/bigfile/file[blk], where
 //
 //	    # see below about file.δtail
-//	    # XXX -> file.δtail.LastRevOf(#blk, zhead.at)
+//	    # XXX -> file.δtail.LastBlkRev(#blk, zhead.at)
 //	    rev = max(file.δtail.by(#blk)) || min(rev ∈ file.δtail) || zhead.at
 //
 //	- invalidate head/bigfile/file[blk] in OS file cache.
@@ -332,14 +331,14 @@ package main
 //   7.1) load blkdata for head/bigfile/file[blk] @zhead.at .
 //
 //	while loading this also gives upper bound estimate of when the block
-//	was last changed:
+//	was last changed:	XXX kill upper bound -> populate and use δFtail
 //
 //	  rev(blk) ≤ max(_.serial for _ in (ZBlk(#blk), all BTree/Bucket that lead to ZBlk))
 //
 //	it is not exact because BTree/Bucket can change (e.g. rebalance)
 //	but still point to the same k->ZBlk.
 //
-//	we also use file.δtail to find either exact blk revision:	XXX
+//	we also use file.δtail to find either exact blk revision:	XXX just use δFtail
 //
 //	  rev(blk) = max(file.δtail.by(#blk) -> []rev↑)
 //
@@ -401,6 +400,13 @@ package main
 //
 // XXX For every ZODB connection a dedicated read-only transaction is maintained.
 
+// XXX notation
+//
+// δZ    - changes in ZODB space
+// δB    - changes in BTree*s* space
+// δF    - changes in File*s* space
+// δfile - changes in File(1) space
+
 import (
 	"bufio"
 	"context"
@@ -670,7 +676,6 @@ func (root *Root) zwatcher(ctx context.Context) (err error) {
 
 		traceZWatch("zevent: %s", zevent)
 
-		var zδ *zodb.EventCommit
 		switch zevent := zevent.(type) {
 		default:
 			return fmt.Errorf("unexpected event: %T", zevent)
@@ -679,15 +684,13 @@ func (root *Root) zwatcher(ctx context.Context) (err error) {
 			return zevent.Err
 
 		case *zodb.EventCommit:
-			zδ = zevent
+			root.handleδZ(zevent)
 		}
-
-		root.zδhandle1(zδ)
 	}
 }
 
-// zδhandle1 handles 1 change event from ZODB notification.
-func (root *Root) zδhandle1(zδ *zodb.EventCommit) {
+// handleδZ handles 1 change event from ZODB notification.
+func (root *Root) handleδZ(δZ *zodb.EventCommit) {
 	head := root.head
 
 	// while we are invalidating OS cache, make sure that nothing, that
@@ -734,8 +737,8 @@ retry:
 
 	//fmt.Printf("\n\n\n")
 
-	// zδ = (tid↑, []oid)
-	for _, oid := range zδ.Changev {
+	// δZ = (tid↑, []oid)
+	for _, oid := range δZ.Changev {
 		// XXX zhead.Cache() lock/unlock
 		obj := zhead.Cache().Get(oid)
 		if obj == nil {
@@ -796,7 +799,7 @@ retry:
 	// XXX no indexMu lock needed because head is Locked
 	// XXX stub -> TODO full δbtree | update indexLooked itself
 	//fmt.Printf("\nbtreeChangev: %v\n", btreeChangev)
-	δf := bfdir.δFtail.Update(zδ)
+	δf := bfdir.δFtail.Update(δZ)
 	//fmt.Printf("xfiles: %v\n", xfiles)
 	for _, δ := range δf.Changev {
 		file := δ.File
@@ -847,13 +850,13 @@ retry:
 		panic(err)	// XXX
 	}
 
-	// resync .zhead to zδ.tid
+	// resync .zhead to δZ.tid
 	// XXX -> Head.Resync() ?
 
 	// 1. abort old and resync to new txn/at
 	transaction.Current(zhead.txnCtx).Abort()
 	_, ctx = transaction.New(context.Background()) // XXX bg ok?
-	err = zhead.Resync(ctx, zδ.Tid)
+	err = zhead.Resync(ctx, δZ.Tid)
 	if err != nil {
 		panic(err)	// XXX
 	}
@@ -876,7 +879,7 @@ retry:
 
 	// notify .wcfs/zhead
 	for sk := range gdebug.zheadSockTab {
-		_, err := fmt.Fprintf(sk, "%s\n", zδ.Tid)
+		_, err := fmt.Fprintf(sk, "%s\n", δZ.Tid)
 		if err != nil {
 			log.Error(err)	// XXX errctx, -> warning?
 			sk.Close()