/// <summary>
/// Rename a collection (do not support transactions)
/// </summary>
public async Task <bool> RenameCollectionAsync(string collection, string newName)
{
if (collection.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(collection));
}
if (newName.IsNullOrWhiteSpace())
{
throw new ArgumentNullException(nameof(newName));
}
// rename collection is possible only in exclusive transaction for this
if (_transaction != null)
{
throw LiteException.AlreadyExistsTransaction();
}
// check for collection name
if (collection.Equals(newName, StringComparison.OrdinalIgnoreCase))
{
throw LiteException.InvalidCollectionName(newName, "New name must be different from current name");
}
// checks if newName are compatible
CollectionService.CheckName(newName, _header);
return(await this.AutoTransaction(async transaction =>
{
var currentSnapshot = await transaction.CreateSnapshot(LockMode.Write, collection, false);
var newSnapshot = await transaction.CreateSnapshot(LockMode.Write, newName, false);
if (currentSnapshot.CollectionPage == null)
{
return false;
}
// checks if do not already exists this collection name
if (_header.GetCollectionPageID(newName) != uint.MaxValue)
{
throw LiteException.AlreadyExistsCollectionName(newName);
}
// rename collection and set page as dirty (there is no need to set IsDirty in HeaderPage)
transaction.Pages.Commit += (h) =>
{
h.RenameCollection(collection, newName);
};
return true;
}));
}
public Snapshot(LockMode mode, string collectionName, HeaderPage header, uint transactionID, TransactionPages transPages, LockService locker, WalIndexService walIndex, DiskReader reader, bool addIfNotExists)
{
_mode = mode;
_collectionName = collectionName;
_header = header;
_transactionID = transactionID;
_transPages = transPages;
_locker = locker;
_walIndex = walIndex;
_reader = reader;
// enter in lock mode according initial mode
if (mode == LockMode.Read)
{
_locker.EnterRead(_collectionName);
}
else
{
_locker.EnterReserved(_collectionName);
}
// get lastest read version from wal-index
_readVersion = _walIndex.CurrentReadVersion;
var srv = new CollectionService(_header, this, _transPages);
// read collection (create if new - load virtual too)
srv.Get(_collectionName, addIfNotExists, ref _collectionPage);
// clear local pages (will clear _collectionPage link reference)
if (_collectionPage != null)
{
// local pages contains only data/index pages
_localPages.Remove(_collectionPage.PageID);
}
}
