Raven.Database.DocumentDatabase.GetIndexEtag C# (CSharp) Method

		public Guid GetIndexEtag(string indexName)
		{
			Guid lastDocEtag = Guid.Empty;
			Guid? lastReducedEtag = null;
			bool isStale = false;
			int touchCount = 0;
			TransactionalStorage.Batch(accessor =>
			{
				isStale = accessor.Staleness.IsIndexStale(indexName, null, null);
				lastDocEtag = accessor.Staleness.GetMostRecentDocumentEtag();
				lastReducedEtag = accessor.Staleness.GetMostRecentReducedEtag(indexName);
				touchCount = accessor.Staleness.GetIndexTouchCount(indexName);
			});
			var indexDefinition = GetIndexDefinition(indexName);
			if (indexDefinition == null)
				return Guid.NewGuid(); // this ensures that we will get the normal reaction of IndexNotFound later on.
			using (var md5 = MD5.Create())
			{
				var list = new List<byte>();
				list.AddRange(indexDefinition.GetIndexHash());
				list.AddRange(Encoding.Unicode.GetBytes(indexName));
				list.AddRange(lastDocEtag.ToByteArray());
				list.AddRange(BitConverter.GetBytes(touchCount));
				list.AddRange(BitConverter.GetBytes(isStale));
				if (lastReducedEtag != null)
				{
					list.AddRange(lastReducedEtag.Value.ToByteArray());
				}
				return new Guid(md5.ComputeHash(list.ToArray()));
			}
		}
	}