private async Task SnapshotAsync(CancellationToken cancellation)
{
var snapshotRevisionThreshold = _options.SnapshotRevisionThreshold;
if (snapshotRevisionThreshold < 0)
{
snapshotRevisionThreshold = 20;
}
using (var scope = _serviceProvider.CreateScope())
{
var scopedServiceProvider = scope.ServiceProvider;
var entityStorageEngine = scopedServiceProvider.GetRequiredService <IEntityStorageEngine>();
var enumerator = default(IAsyncEnumerator <IStream>);
try
{
enumerator = _streamStore.OpenStreamsToSnapshotAsync(snapshotRevisionThreshold, cancellation).GetEnumerator();
while (await enumerator.MoveNext(cancellation))
{
var stream = enumerator.Current;
if (stream.Snapshot == null && !stream.Commits.Any())
{
continue;
}
var serializedEntity = default(JToken);
if (stream.Snapshot == null)
{
serializedEntity = StreamRoot;
}
else
{
serializedEntity = JToken.Parse(CompressionHelper.Unzip(stream.Snapshot.Payload as byte[]));
}
foreach (var commit in stream.Commits)
{
serializedEntity = _differ.Patch(serializedEntity, JToken.Parse(CompressionHelper.Unzip(commit.Body as byte[])));
}
await stream.AddSnapshotAsync(CompressionHelper.Zip(serializedEntity.ToString()), cancellation);
}
}
finally
{
enumerator?.Dispose();
}
}
}