X at2Before & co -> xzodb

go/internal/xzodb/xzodb.go

+// Copyright (C) 2017-2021  Nexedi SA and Contributors.
+//                          Kirill Smelkov <kirr@nexedi.com>
+//
+// This program is free software: you can Use, Study, Modify and Redistribute
+// it under the terms of the GNU General Public License version 3, or (at your
+// option) any later version, as published by the Free Software Foundation.
+//
+// You can also Link and Combine this program with other software covered by
+// the terms of any of the Free Software licenses or any of the Open Source
+// Initiative approved licenses and Convey the resulting work. Corresponding
+// source of such a combination shall include the source code for all other
+// software used.
+//
+// This program is distributed WITHOUT ANY WARRANTY; without even the implied
+// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+// See COPYING file for full licensing terms.
+// See https://www.nexedi.com/licensing for rationale and options.
+
+// Package xzodb complements package zodb.
+package xzodb
+
+import (
+	"lab.nexedi.com/kirr/neo/go/zodb"
+)
+
+// At2Before converts at to before for ZODB load semantics taking edge cases into account.
+//
+// For most values it is
+//
+//	before = at + 1		; at < ∞
+//
+// but at ∞ (zodb.TidMax) it is just
+//
+//	before = at		; at = ∞
+func At2Before(at zodb.Tid) (before zodb.Tid) {
+	if at < zodb.TidMax {
+		return at + 1
+	} else {
+		// XXX do we need to care here also for at > zodb.TidMax (zodb.Tid is currently unsigned)
+		return zodb.TidMax
+	}
+}
+
+// Before2At is the reverse function to At2Before
+func Before2At(before zodb.Tid) (at zodb.Tid) {
+	if before < zodb.TidMax {
+		// XXX before = 0 ?
+		return before - 1
+	} else {
+		// XXX before > zodb.TidMax (same as in At2Before) ?
+		return zodb.TidMax
+	}
+}

go/neo/client.go

@@ -37,6 +37,7 @@ import (
 	"lab.nexedi.com/kirr/go123/xnet"
 
 	"lab.nexedi.com/kirr/neo/go/internal/xzlib"
+	"lab.nexedi.com/kirr/neo/go/internal/xzodb"
 	"lab.nexedi.com/kirr/neo/go/neo/internal/xsha1"
 	"lab.nexedi.com/kirr/neo/go/neo/neonet"
 	"lab.nexedi.com/kirr/neo/go/neo/proto"
@@ -557,7 +558,7 @@ func (c *Client) Load(ctx context.Context, xid zodb.Xid) (buf *mem.Buf, serial z
 	// on the wire it comes as "before", not "at"
 	req := proto.GetObject{
 		Oid:    xid.Oid,
-		Before: at2Before(xid.At),
+		Before: xzodb.At2Before(xid.At),
 		At:     proto.INVALID_TID,
 	}
 

go/neo/neo_test.go

@@ -32,6 +32,7 @@ import (
 
 	"lab.nexedi.com/kirr/neo/go/neo/proto"
 	"lab.nexedi.com/kirr/neo/go/zodb"
+	"lab.nexedi.com/kirr/neo/go/internal/xzodb"
 
 	"lab.nexedi.com/kirr/go123/exc"
 	"lab.nexedi.com/kirr/go123/tracing/tracetest"
@@ -236,7 +237,7 @@ func _TestMasterStorage(t0 *tEnv) {
 	// ... -> GetObject(xid1)
 	tCS.Expect(conntx("c:2", "s:3", 3, &proto.GetObject{
 		Oid:	xid1.Oid,
-		Before:	at2Before(xid1.At),
+		Before:	xzodb.At2Before(xid1.At),
 		At:     proto.INVALID_TID,
 	}))
 	tCS.Expect(conntx("s:3", "c:2", 3, &proto.AnswerObject{

go/neo/storage.go

@@ -36,6 +36,7 @@ import (
 	"lab.nexedi.com/kirr/neo/go/internal/task"
 	xxcontext "lab.nexedi.com/kirr/neo/go/internal/xcontext"
 	"lab.nexedi.com/kirr/neo/go/internal/xio"
+	"lab.nexedi.com/kirr/neo/go/internal/xzodb"
 
 	"lab.nexedi.com/kirr/go123/xcontext"
 	"lab.nexedi.com/kirr/go123/xerr"
@@ -551,7 +552,7 @@ func (stor *Storage) serveClient1(ctx context.Context, req proto.Msg) (resp prot
 		if req.At != proto.INVALID_TID {
 			xid.At = req.At
 		} else {
-			xid.At = before2At(req.Before)
+			xid.At = xzodb.Before2At(req.Before)
 		}
 
 		obj, err := stor.back.Load(ctx, xid)

go/neo/util.go

@@ -25,7 +25,6 @@ import (
 	"io"
 	"net/url"
 
-	"lab.nexedi.com/kirr/neo/go/zodb"
 	"lab.nexedi.com/kirr/neo/go/internal/log"
 )
 
@@ -38,36 +37,6 @@ func lclose(ctx context.Context, c io.Closer) {
 	}
 }
 
-// at2Before converts at to before for ZODB load semantics taking edge cases into account.
-//
-// For most values it is
-//
-//	before = at + 1		; at < ∞
-//
-// but at ∞ (zodb.TidMax) it is just
-//
-//	before = at		; at = ∞
-func at2Before(at zodb.Tid) (before zodb.Tid) {
-	if at < zodb.TidMax {
-		return at + 1
-	} else {
-		// XXX do we need to care here also for at > zodb.TidMax (zodb.Tid is currently unsigned)
-		return zodb.TidMax
-	}
-}
-
-// before2At is the reverse function to at2Before
-func before2At(before zodb.Tid) (at zodb.Tid) {
-	if before < zodb.TidMax {
-		// XXX before = 0 ?
-		return before - 1
-	} else {
-		// XXX before > zodb.TidMax (same as in at2Before) ?
-		return zodb.TidMax
-	}
-}
-
-
 // parseQuery parses query string into regular map.
 // see also url.ParseQuery
 func parseQuery(query string) (map[string]string, error) {

go/zodb/storage/zeo/zeo.go

-// Copyright (C) 2018-2020  Nexedi SA and Contributors.
+// Copyright (C) 2018-2021  Nexedi SA and Contributors.
 //                          Kirill Smelkov <kirr@nexedi.com>
 //
 // This program is free software: you can Use, Study, Modify and Redistribute
@@ -32,6 +32,7 @@ import (
 	"lab.nexedi.com/kirr/go123/mem"
 	"lab.nexedi.com/kirr/go123/xerr"
 	"lab.nexedi.com/kirr/go123/xnet"
+	"lab.nexedi.com/kirr/neo/go/internal/xzodb"
 	"lab.nexedi.com/kirr/neo/go/zodb"
 )
 
@@ -92,7 +93,7 @@ func (z *zeo) Load(ctx context.Context, xid zodb.Xid) (buf *mem.Buf, serial zodb
 
 	rpc := z.rpc("loadBefore")
 	enc := z.link.enc
-	xres, err := rpc.call(ctx, enc.Oid(xid.Oid), enc.Tid(xid.At+1)) // XXX at2Before
+	xres, err := rpc.call(ctx, enc.Oid(xid.Oid), enc.Tid(xzodb.At2Before(xid.At)))
 	if err != nil {
 		return nil, 0, err
 	}