static public void SyncWith(this SessionBase sessionToUpdate, SessionBase sessionToRead, Func <SessionBase, UInt64, Change, bool> doUpdate)
{
UInt64 currentVersion;
UInt64 pageToReadVersion;
bool conflictFound = false;
using (var reader = sessionToRead.BeginRead())
{
Changes changes = (Changes)sessionToRead.Open(5, 1, 1, false);
if (changes != null)
{
using (var updater = sessionToUpdate.BeginUpdate())
{
var dbs = sessionToUpdate.OpenAllDatabases();
ReplicaSync matchingReplicaSync = null;
foreach (ReplicaSync sync in sessionToUpdate.AllObjects <ReplicaSync>())
{
if (sync.SyncFromHost == sessionToRead.SystemHostName && sync.SyncFromPath == sessionToRead.SystemDirectory)
{
matchingReplicaSync = sync;
break;
}
}
if (changes.ChangeList.Count > 0)
{
foreach (TransactionChanges transactionChanges in changes.ChangeList)
{
if (matchingReplicaSync == null || matchingReplicaSync.TransactionNumber < transactionChanges.TransactionNumber)
{
foreach (Change change in transactionChanges.ChangeList)
{
Database dbToUpdate = sessionToUpdate.OpenDatabase(change.DatabaseId, false, false);
Database dbToRead = sessionToRead.OpenDatabase(change.DatabaseId, false, false);
string dbName = dbToRead != null ? dbToRead.Name : null;
if (change.Deleted)
{
if (dbToUpdate == null) // does not exist
{
continue;
}
if (change.PageId == 0) // Database delete
{
currentVersion = dbToUpdate.Page.PageInfo.VersionNumber;
if (currentVersion < change.Version)
{
sessionToUpdate.DeleteDatabase(dbToUpdate);
}
else
{
conflictFound = true;
if (doUpdate(sessionToUpdate, currentVersion, change))
{
sessionToUpdate.DeleteDatabase(dbToUpdate);
}
}
}
else
{
Page page = sessionToUpdate.OpenPage(dbToUpdate, change.PageId);
if (page == null) // page does not exist
{
continue;
}
currentVersion = page.PageInfo.VersionNumber;
if (currentVersion < change.Version)
{
sessionToUpdate.DeletePage(dbToUpdate, page);
}
else
{
conflictFound = true;
if (doUpdate(sessionToUpdate, currentVersion, change))
{
sessionToUpdate.DeleteDatabase(dbToUpdate);
}
}
}
}
else
{
if (dbToUpdate == null) // does not exist
{
dbToUpdate = sessionToUpdate.NewDatabase(change.DatabaseId, 0, dbName);
}
if (change.PageId > 0)
{
Page pageToUpdate = sessionToUpdate.OpenPage(dbToUpdate, change.PageId);
Page pageToRead = sessionToRead.OpenPage(dbToRead, change.PageId);
if (pageToRead == null) // upcoming (not yet processed) changes must have deleted this page
{
continue;
}
currentVersion = pageToUpdate == null ? 0 : pageToUpdate.PageInfo.VersionNumber;
pageToReadVersion = pageToRead.PageInfo.VersionNumber;
if (currentVersion < pageToReadVersion || dbToUpdate.IsNew)
{
sessionToUpdate.ReplacePage(dbToUpdate, pageToUpdate, pageToRead);
}
else
{
conflictFound = true;
if (doUpdate(sessionToUpdate, currentVersion, change))
{
sessionToUpdate.ReplacePage(dbToUpdate, pageToUpdate, pageToRead);
}
}
}
}
}
}
}
UInt64 lastTransactionNumber = changes.ChangeList.Last().TransactionNumber;
if (matchingReplicaSync != null)
{
matchingReplicaSync.TransactionNumber = lastTransactionNumber;
}
if (conflictFound)
{
sessionToUpdate.Verify();
}
sessionToUpdate.Commit();
if (matchingReplicaSync == null)
{
sessionToUpdate.BeginUpdate(); // separate transaction or else gets confused with databases added by sync
matchingReplicaSync = new ReplicaSync(sessionToRead, lastTransactionNumber);
sessionToUpdate.Persist(matchingReplicaSync);
sessionToUpdate.Commit();
}
}
}
}
}
}
