// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package vsync

import (
	"v.io/syncbase/x/ref/services/syncbase/server/interfaces"
)

// Key prefixes for sync data structures. All these prefixes are prepended with
// util.SyncPrefix.
const (
	logPrefix  = "log"
	dbssPrefix = "dbss"
	dagPrefix  = "dag"
	sgPrefix   = "sg"
)

// syncData represents the persistent state of the sync module.
type syncData struct {
	Id uint64
}

// dbSyncState represents the persistent sync state of a Database.
type dbSyncState struct {
	Gen        uint64               // local generation number incremented on every local update.
	CheckptGen uint64               // local generation number advertised to remote peers (used by the responder).
	GenVec     interfaces.GenVector // generation vector capturing the locally-known generations of remote peers.
}

// localLogRec represents the persistent local state of a log record. Metadata
// is synced across peers, while pos is local-only.
type localLogRec struct {
	Metadata interfaces.LogRecMetadata
	Pos      uint64 // position in the Database log.
}