/// <summary>
/// Searches for the first object that is lasser than a hypothetical limit object.
/// </summary>
/// <typeparam name="T">The typed enumerator uses
/// the object serializer of <typeparamref name="T"/> to deserialize objects by default.</typeparam>
/// <param name="Locked">If the resulting enumerator should be opened in locked mode or not.</param>
/// <param name="Object">Limit object to search for.</param>
/// <returns>Enumerator that can be used to enumerate objects in index order. First object will be the first
/// object that is lesser than the limit object. If null is returned, the search operation could
/// not be performed.</returns>
public async Task <IndexBTreeFileEnumerator <T> > FindLastLesserThan <T>(bool Locked, GenericObject Object)
{
byte[] Key = this.recordHandler.Serialize(Guid.Empty, Object, this.genericSerializer, MissingFieldAction.First);
if (Key.Length > this.indexFile.InlineObjectSizeLimit)
{
return(null);
}
IndexBTreeFileEnumerator <T> Result = null;
try
{
Result = new IndexBTreeFileEnumerator <T>(this, this.recordHandler);
if (Locked)
{
await Result.LockRead();
}
BlockInfo Leaf = await this.indexFile.FindLeafNodeLocked(Key);
Result.SetStartingPoint(Leaf);
}
catch (Exception ex)
{
if (Result != null)
{
Result.Dispose();
Result = null;
}
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(ex).Throw();
}
return(Result);
}
/// <summary>
/// Searches for the first object that is greater than a hypothetical limit object.
/// </summary>
/// <typeparam name="T">The typed enumerator uses
/// the object serializer of <typeparamref name="T"/> to deserialize objects by default.</typeparam>
/// <param name="Locked">If the resulting enumerator should be opened in locked mode or not.</param>
/// <param name="Object">Limit object to search for.</param>
/// <returns>Enumerator that can be used to enumerate objects in index order. First object will be the first
/// object that is greater than the limit object. If null is returned, the search operation could
/// not be performed.</returns>
public async Task <IndexBTreeFileEnumerator <T> > FindFirstGreaterThan <T>(bool Locked, GenericObject Object)
{
byte[] Key = this.recordHandler.Serialize(GuidMax, Object, this.genericSerializer, MissingFieldAction.Last);
if (Key.Length > this.indexFile.InlineObjectSizeLimit)
{
return(null);
}
IndexBTreeFileEnumerator <T> Result = null;
await this.indexFile.Lock();
try
{
BlockInfo Leaf = await this.indexFile.FindLeafNodeLocked(Key);
Result = new IndexBTreeFileEnumerator <T>(this, Locked, this.recordHandler, Leaf);
if (!Locked)
{
await this.indexFile.Release();
}
}
catch (Exception ex)
{
if (Result != null)
{
Result.Dispose();
Result = null;
}
else
{
await this.indexFile.Release();
}
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(ex).Throw();
}
return(Result);
}
