protected override Task <StreamMessagesPage> ReadStreamBackwardsInternal(
string streamId,
int fromVersionInclusive,
int count,
CancellationToken cancellationToken)
{
GuardAgainstDisposed();
using (_lock.UseReadLock())
{
InMemoryStream stream;
if (!_streams.TryGetValue(streamId, out stream))
{
var notFound = new StreamMessagesPage(streamId,
PageReadStatus.StreamNotFound,
fromVersionInclusive,
-1,
-1,
ReadDirection.Backward,
true);
return(Task.FromResult(notFound));
}
var events = new List <StreamMessage>();
var i = fromVersionInclusive == StreamVersion.End ? stream.Events.Count - 1 : fromVersionInclusive;
while (i >= 0 && count > 0)
{
var inMemorymessage = stream.Events[i];
var message = new StreamMessage(
streamId,
inMemorymessage.MessageId,
inMemorymessage.StreamVersion,
inMemorymessage.Position,
inMemorymessage.Created,
inMemorymessage.Type,
inMemorymessage.JsonData,
inMemorymessage.JsonMetadata);
events.Add(message);
i--;
count--;
}
var lastStreamVersion = stream.Events.Last().StreamVersion;
var nextStreamVersion = events.Last().StreamVersion - 1;
var endOfStream = nextStreamVersion < 0;
var page = new StreamMessagesPage(
streamId,
PageReadStatus.Success,
fromVersionInclusive,
nextStreamVersion,
lastStreamVersion,
ReadDirection.Backward,
endOfStream,
events.ToArray());
return(Task.FromResult(page));
}
}
public ReadStreamTheory(
string streamId,
int start,
int pageSize,
StreamMessagesPage expectedStreamMessagesPage)
{
StreamId = streamId;
Start = start;
PageSize = pageSize;
ExpectedStreamMessagesPage = expectedStreamMessagesPage;
}
private async Task <StreamMessagesPage> FilterExpired(
StreamMessagesPage page,
CancellationToken cancellationToken)
{
if (page.StreamId.StartsWith("$"))
{
return(page);
}
var maxAge = await _metadataMaxAgeCache.GetMaxAge(page.StreamId, cancellationToken);
if (!maxAge.HasValue)
{
return(page);
}
var currentUtc = GetUtcNow();
var valid = new List <StreamMessage>();
foreach (var message in page.Messages)
{
if (message.CreatedUtc.AddSeconds(maxAge.Value) > currentUtc)
{
valid.Add(message);
}
else
{
PurgeExpiredMessage(message);
}
}
return(new StreamMessagesPage(
page.StreamId,
page.Status,
page.FromStreamVersion,
page.NextStreamVersion,
page.LastStreamVersion,
page.ReadDirection,
page.IsEndOfStream,
valid.ToArray()));
}
