public async ValueTask <bool> MoveNextAsync()
{
this.cancellationToken.ThrowIfCancellationRequested();
if (!await this.crossPartitionEnumerator.MoveNextAsync())
{
this.Current = default;
return(false);
}
TryCatch <CrossPartitionPage <ReadFeedPage, ReadFeedState> > monadicCrossPartitionPage = this.crossPartitionEnumerator.Current;
if (monadicCrossPartitionPage.Failed)
{
this.Current = TryCatch <ReadFeedPage> .FromException(monadicCrossPartitionPage.Exception);
return(true);
}
CrossPartitionPage <ReadFeedPage, ReadFeedState> crossPartitionPage = monadicCrossPartitionPage.Result;
ReadFeedPage backendPage = crossPartitionPage.Page;
CrossPartitionState <ReadFeedState> crossPartitionState = crossPartitionPage.State;
ReadFeedState state;
if (crossPartitionState != null)
{
IReadOnlyList <(FeedRangeInternal, ReadFeedState)> rangesAndStates = crossPartitionState.Value;
List <CosmosElement> changeFeedContinuationTokens = new List <CosmosElement>();
foreach ((FeedRangeInternal range, ReadFeedState readFeedState) in rangesAndStates)
{
this.cancellationToken.ThrowIfCancellationRequested();
ReadFeedContinuationToken readFeedContinuationToken = new ReadFeedContinuationToken(
range,
readFeedState);
CosmosElement cosmosElementChangeFeedContinuationToken = ReadFeedContinuationToken.ToCosmosElement(readFeedContinuationToken);
changeFeedContinuationTokens.Add(cosmosElementChangeFeedContinuationToken);
}
CosmosArray cosmosElementTokens = CosmosArray.Create(changeFeedContinuationTokens);
state = new ReadFeedState(cosmosElementTokens);
}
else
{
state = null;
}
ReadFeedPage compositePage = new ReadFeedPage(backendPage.Content, backendPage.RequestCharge, backendPage.ActivityId, backendPage.Diagnostics, state);
this.Current = TryCatch <ReadFeedPage> .FromResult(compositePage);
return(true);
}
public static TryCatch <FeedRangeState <ReadFeedState> > CreateFromCosmosElement(CosmosElement cosmosElement)
{
if (cosmosElement == null)
{
throw new ArgumentNullException(nameof(cosmosElement));
}
if (!(cosmosElement is CosmosObject cosmosObject))
{
return(TryCatch <FeedRangeState <ReadFeedState> > .FromException(
new FormatException(
$"Expected object for ChangeFeed Continuation: {cosmosElement}.")));
}
if (!cosmosObject.TryGetValue(PropertyNames.FeedRange, out CosmosElement feedRangeCosmosElement))
{
return(TryCatch <FeedRangeState <ReadFeedState> > .FromException(
new FormatException(
$"Expected '{PropertyNames.FeedRange}' for '{nameof(FeedRangeState<ReadFeedState>)}': {cosmosElement}.")));
}
if (!cosmosObject.TryGetValue(PropertyNames.State, out CosmosElement stateCosmosElement))
{
return(TryCatch <FeedRangeState <ReadFeedState> > .FromException(
new FormatException(
$"Expected '{PropertyNames.State}' for '{nameof(FeedRangeState<ReadFeedState>)}': {cosmosElement}.")));
}
TryCatch <FeedRangeInternal> monadicFeedRange = FeedRangeCosmosElementSerializer.MonadicCreateFromCosmosElement(feedRangeCosmosElement);
if (monadicFeedRange.Failed)
{
return(TryCatch <FeedRangeState <ReadFeedState> > .FromException(
new FormatException(
$"Failed to parse '{PropertyNames.FeedRange}' for '{nameof(FeedRangeState<ReadFeedState>)}': {cosmosElement}.",
innerException : monadicFeedRange.Exception)));
}
ReadFeedState readFeedState;
if (stateCosmosElement is CosmosNull)
{
readFeedState = ReadFeedState.Beginning();
}
else
{
readFeedState = ReadFeedState.Continuation(stateCosmosElement);
}
return(TryCatch <FeedRangeState <ReadFeedState> > .FromResult(
new FeedRangeState <ReadFeedState>(
monadicFeedRange.Result,
readFeedState)));
}
public ReadFeedContinuationToken(FeedRangeInternal feedRange, ReadFeedState readFeedState)
{
this.Range = feedRange ?? throw new ArgumentNullException(nameof(feedRange));
this.State = readFeedState ?? throw new ArgumentNullException(nameof(readFeedState));
}