public ProjectionGroupState(
string name,
bool suspended = false,
Exception exception = null,
AllStreamPosition checkpoint = default(AllStreamPosition))
{
Name = name;
Suspended = suspended;
Exception = exception;
Checkpoint = checkpoint;
}
public ReadAllPage(
AllStreamPosition fromPosition,
AllStreamPosition nextPosition,
bool isEnd,
IReadOnlyCollection <Envelope> messages
)
{
FromPosition = fromPosition;
NextPosition = nextPosition;
IsEnd = isEnd;
Messages = messages;
}
public async Task Project(Envelope message, CancellationToken cancellationToken = default(CancellationToken))
{
var checkpoint = message.Checkpoint;
if (_lastCheckpoint == null || checkpoint > _lastCheckpoint)
{
await _inner.Project(message, cancellationToken).ConfigureAwait(false);
_lastCheckpoint = checkpoint;
_notifyCheckpoint?.Invoke(AllStreamPosition.FromNullableInt64(_lastCheckpoint));
}
}
public CheckpointProjection(
IStatefulProjection inner,
CheckpointStore checkpointStore,
Action <AllStreamPosition> notifyCheckpoint = null)
{
_inner = inner;
_checkpointStore = checkpointStore;
_notifyCheckpoint = notifyCheckpoint;
_lastCheckpoint = _checkpointStore.Read();
_notifyCheckpoint?.Invoke(AllStreamPosition.FromNullableInt64(_lastCheckpoint));
}
public GenericSubscription(
ReadAllPageFunc readAllPage,
AllStreamPosition fromPosition,
Func <CancellationToken, Task> waitForEvent,
MessageReceived onMessage,
Func <Exception, Task> onSubscriptionError,
HasCaughtUp hasCaughtUp)
{
_readAllPage = readAllPage;
FromPosition = fromPosition;
_nextPosition = new AllStreamPosition(fromPosition.ToNullableInt64() + 1 ?? 0);
_waitForEvent = waitForEvent;
_onMessage = onMessage;
_hasCaughtUp = hasCaughtUp ?? (() => Task.CompletedTask);
_onSubscriptionError = onSubscriptionError ?? (_ => Task.CompletedTask);
LastPosition = fromPosition;
Task.Run(PullAndPush);
}
private async Task Push(ReadAllPage page)
{
foreach (var message in page.Messages)
{
if (_disposed.IsCancellationRequested)
{
_disposed.Token.ThrowIfCancellationRequested();
}
_nextPosition = new AllStreamPosition(message.Checkpoint.ToInt64() + 1);
LastPosition = message.Checkpoint;
try
{
await _onMessage(this, message, _disposed.Token).ConfigureAwait(false);
}
catch (Exception ex) when(!(ex is OperationCanceledException))
{
await _onSubscriptionError(ex).ConfigureAwait(false);
throw;
}
}
}
public ProjectionGroupState MoveTo(AllStreamPosition checkpoint) => new ProjectionGroupState(Name, false, Exception, checkpoint);
public AllStreamPosition ReadCheckpoint(string name) =>
_checkpointStores.TryGetValue(name, out CheckpointStore store)
? AllStreamPosition.FromNullableInt64(store.Read())
: AllStreamPosition.None;
public void MoveTo(string name, AllStreamPosition checkpoint) => this[name] = this[name].MoveTo(checkpoint);