public async Task CommitStreamReaderPositionAsync(
string streamName,
EventStreamReaderId readerId,
StreamVersion readerVersion)
{
Require.NotEmpty(streamName, "streamName");
Require.NotNull(readerId, "readerId");
var properties = await m_table.ReadStreamReaderPropertiesAsync(streamName, readerId);
if (properties == null)
{
await m_table.InserStreamReaderPropertiesAsync(
streamName,
readerId,
readerVersion);
}
else
{
var readerVersionValue = (int)readerVersion;
var savedVersionValue = (int)properties[EventJournalTableRowPropertyNames.Version];
var etag = (string)properties[KnownProperties.ETag];
Ensure.True(savedVersionValue <= readerVersionValue,
"Saved reader stream version is greater then passed value.");
if (readerVersionValue != savedVersionValue)
{
await m_table.UpdateStreamReaderPropertiesAsync(streamName, readerId, readerVersion, etag);
}
}
}
public async Task <IEnumerable <StreamReaderDescription> > GetStreamReadersDescriptionsAsync(string streamName)
{
Require.NotEmpty(streamName, nameof(streamName));
var streamReadersProperties = await m_table.ReadAllStreamReadersPropertiesAsync(streamName);
var descriptions = streamReadersProperties.Select(streamReaderProperties => new StreamReaderDescription(
streamName,
EventStreamReaderId.Parse(streamReaderProperties[KnownProperties.RowKey].ToString().Split('|').Last()),
StreamVersion.Create((int)streamReaderProperties[EventJournalTableRowPropertyNames.Version])));
return(descriptions);
}
public async Task <IEventStreamCursor> OpenEventStreamCursorAsync(string streamName, EventStreamReaderId readerId, int sliceSize)
{
Require.NotEmpty(streamName, "streamName");
Require.Positive(sliceSize, "sliceSize");
var fromVersion = await ReadStreamReaderPositionAsync(streamName, readerId);
var header = await ReadStreamHeaderAsync(streamName);
if (header == EventStreamHeader.Unknown)
{
return(EventStreamCursor.UninitializedStream);
}
if (header.Version <= fromVersion)
{
return(EventStreamCursor.CreateEmptyCursor(header, fromVersion));
}
return(EventStreamCursor.CreateActiveCursor(
header,
fromVersion.Increment(),
from => m_table.FetchStreamEvents(streamName, header, from, sliceSize)));
}
public async Task <StreamVersion> ReadStreamReaderPositionAsync(string streamName, EventStreamReaderId readerId)
{
Require.NotEmpty(streamName, "streamName");
Require.NotNull(readerId, "readerId");
var properties = await m_table.ReadStreamReaderPropertiesAsync(streamName, readerId);
if (properties == null)
{
return(StreamVersion.Unknown);
}
return(StreamVersion.Create((int)properties[EventJournalTableRowPropertyNames.Version]));
}
