public static CosmosElement ToCosmosElement(ChangeFeedContinuationToken changeFeedContinuationToken)
{
return(CosmosObject.Create(new Dictionary <string, CosmosElement>()
{
{
PropertyNames.FeedRange,
FeedRangeCosmosElementSerializer.ToCosmosElement(changeFeedContinuationToken.Range)
},
{
PropertyNames.State,
ChangeFeedStateCosmosElementSerializer.ToCosmosElement(changeFeedContinuationToken.State)
}
}));
}
public async ValueTask <bool> MoveNextAsync()
{
this.cancellationToken.ThrowIfCancellationRequested();
if (this.bufferedException.HasValue)
{
this.Current = this.bufferedException.Value;
this.bufferedException = null;
return(true);
}
if (!await this.crossPartitionEnumerator.MoveNextAsync())
{
throw new InvalidOperationException("ChangeFeed should always have a next page.");
}
TryCatch <CrossPartitionPage <ChangeFeedPage, ChangeFeedState> > monadicCrossPartitionPage = this.crossPartitionEnumerator.Current;
if (monadicCrossPartitionPage.Failed)
{
this.Current = TryCatch <ChangeFeedPage> .FromException(monadicCrossPartitionPage.Exception);
return(true);
}
CrossPartitionPage <ChangeFeedPage, ChangeFeedState> crossPartitionPage = monadicCrossPartitionPage.Result;
ChangeFeedPage backendPage = crossPartitionPage.Page;
if (backendPage is ChangeFeedNotModifiedPage)
{
// Keep draining the cross partition enumerator until
// We get a non 304 page or we loop back to the same range or run into an exception
FeedRangeInternal originalRange = this.crossPartitionEnumerator.CurrentRange;
double totalRequestCharge = backendPage.RequestCharge;
do
{
if (!await this.crossPartitionEnumerator.MoveNextAsync())
{
throw new InvalidOperationException("ChangeFeed should always have a next page.");
}
monadicCrossPartitionPage = this.crossPartitionEnumerator.Current;
if (monadicCrossPartitionPage.Failed)
{
// Buffer the exception, since we need to return the request charge so far.
this.bufferedException = TryCatch <ChangeFeedPage> .FromException(monadicCrossPartitionPage.Exception);
}
else
{
crossPartitionPage = monadicCrossPartitionPage.Result;
backendPage = crossPartitionPage.Page;
totalRequestCharge += backendPage.RequestCharge;
}
}while (!(backendPage is ChangeFeedSuccessPage ||
this.crossPartitionEnumerator.CurrentRange.Equals(originalRange) ||
this.bufferedException.HasValue));
// Create a page with the aggregated request charge
if (backendPage is ChangeFeedSuccessPage changeFeedSuccessPage)
{
backendPage = new ChangeFeedSuccessPage(
changeFeedSuccessPage.Content,
totalRequestCharge,
changeFeedSuccessPage.ActivityId,
changeFeedSuccessPage.State);
}
else
{
backendPage = new ChangeFeedNotModifiedPage(
totalRequestCharge,
backendPage.ActivityId,
backendPage.State);
}
}
CrossPartitionState <ChangeFeedState> crossPartitionState = crossPartitionPage.State;
List <CosmosElement> changeFeedContinuationTokens = new List <CosmosElement>();
foreach ((FeedRangeInternal range, ChangeFeedState state)rangeAndState in crossPartitionState.Value)
{
ChangeFeedContinuationToken changeFeedContinuationToken = new ChangeFeedContinuationToken(
rangeAndState.range,
rangeAndState.state);
CosmosElement cosmosElementChangeFeedContinuationToken = ChangeFeedContinuationToken.ToCosmosElement(changeFeedContinuationToken);
changeFeedContinuationTokens.Add(cosmosElementChangeFeedContinuationToken);
}
CosmosArray cosmosElementTokens = CosmosArray.Create(changeFeedContinuationTokens);
ChangeFeedState state = ChangeFeedState.Continuation(cosmosElementTokens);
ChangeFeedPage compositePage;
if (backendPage is ChangeFeedSuccessPage successPage)
{
compositePage = new ChangeFeedSuccessPage(
successPage.Content,
successPage.RequestCharge,
successPage.ActivityId,
state);
}
else
{
compositePage = new ChangeFeedNotModifiedPage(
backendPage.RequestCharge,
backendPage.ActivityId,
state);
}
this.Current = TryCatch <ChangeFeedPage> .FromResult(compositePage);
return(true);
}
