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// 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 (
// 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 {
GenVecs interfaces.Knowledge // knowledge capturing the locally-known generations of remote peers for data in Database.
SgGenVecs interfaces.Knowledge // knowledge capturing the locally-known generations of remote peers for syncgroups in Database.
IsPaused bool // tracks whether sync is paused by client.
// 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.
// SgLocalState holds the syncgroup local state, only relevant to this member
// (i.e. the local Syncbase). This is needed for crash recovery of the internal
// state transitions of the syncgroup.
type SgLocalState struct {
// The count of local joiners to the same syncgroup.
NumLocalJoiners uint32
// The syncgroup is watched when the sync Watcher starts processing the
// syncgroup data. When a syncgroup is created or joined, an entry is
// added to the Watcher queue (log) to inform it from which point to
// start accepting store mutations, an asynchronous notification similar
// to regular store mutations. When the Watcher processes that queue
// entry, it sets this bit to true. When Syncbase restarts, the value
// of this bit allows the new sync Watcher to recreate its in-memory
// state by resuming to watch only the prefixes of syncgroups that were
// previously being watched.
Watched bool
// The syncgroup was published here by this remote peer (if non-empty
// string), typically the syncgroup creator. In this case the syncgroup
// cannot be GCed locally even if it has no local joiners.
RemotePublisher string
// The syncgroup is in pending state on a device that learns the current
// state of the syncgroup from another device but has not yet received
// through peer-to-peer sync the history of the changes (DAG and logs).
// This happens in two cases:
// 1- A joiner was accepted into a syncgroup by a syncgroup admin and
// only given the current syncgroup info synchronously and will
// receive the full history later via p2p sync.
// 2- A remote server where the syncgroup is published was told by the
// syncgroup publisher the current syncgroup info synchronously and
// will receive the full history later via p2p sync.
// The pending state is over when the device reaches or exceeds the
// knowledge level indicated in the pending genvec. While SyncPending
// is true, no local syncgroup mutations are allowed (i.e. no join or
// set-spec requests).
SyncPending bool
PendingGenVec interfaces.GenVector
// DagNode holds the information on an object mutation in the DAG. The node
// information is extracted from the log records exchanged between Syncbases.
// They are also stored in the DAG node to improve DAG traversal for conflict
// resolution and pruning without having to fetch the full log record.
type DagNode struct {
Level uint64 // node distance from root
Parents []string // references to parent versions
Logrec string // reference to log record
BatchId uint64 // ID of a write batch
Deleted bool // true if the change was a delete
PermId string // ID of the permissions controlling this version
PermVers string // current version of the permissions object
// BatchInfo holds the information on a write batch:
// * The map of syncable (versioned) objects: {oid: version}
// * The map of linked objects {oid: version} that were not explicitly written
// as part of the batch but were reaffirmed during conflict resolution along
// with other objects written in this batch by the app by choosing
// "pickLocal" or "pickRemote". NOTE: this map is non empty only for batches
// created during conflict resolution. Unlike the Objects map, the collection
// of oid:version present in this map do not point back to this batch. They
// point to the batches that there were originally created in.
// * The total count of batch objects, including non-syncable ones.
// TODO(rdaoud): add support to track the read and scan sets.
type BatchInfo struct {
Objects map[string]string
LinkedObjects map[string]string
Count uint64