public static IAsyncEnumerable <R> Select <T, R>(this IAsyncEnumerable <T> source, Func <T, Task <R> > selector)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (selector == null)
{
throw new ArgumentNullException(nameof(selector));
}
#if CSHARP8
return(Iterator());
async IAsyncEnumerable <R> Iterator()
{
foreach await(var item in source.ConfigureAwait(false))
{
yield return(selector(item).ConfigureAwait(false));
}
}
#elif MONADIC
return(source.SelectMany(async x => Return(await selector(x).ConfigureAwait(false))));
#else
return(new SelectAsyncIteratorWithAsyncSelector <T, R>(source, selector));
#endif
}
/// <summary>
///
/// </summary>
/// <param name="fromSequenceNumber"></param>
/// <param name="maxMessages"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
internal async IAsyncEnumerable <ServiceBusMessage> PeekRangeBySequenceInternal(
long?fromSequenceNumber,
int maxMessages = 1,
[EnumeratorCancellation]
CancellationToken cancellationToken = default)
{
RetriableContext context = CreateRetriableContext(cancellationToken);
ReceivingAmqpLink openedLink =
await context.RunOperation(
async() => await Consumer.ReceiveLink.GetOrCreateAsync(context.TimeSpan)
.ConfigureAwait(false))
.ConfigureAwait(false);
var source = (Source)openedLink.Settings.Source;
if (source.FilterSet.TryGetValue <string>(AmqpClientConstants.SessionFilterName, out var tempSessionId))
{
// If one of the constructors not accepting a SessionId was used, the broker will determine which session to send messages from.
SessionId = tempSessionId;
}
IAsyncEnumerable <ServiceBusMessage> ret = PeekRangeBySequenceInternal(
fromSequenceNumber: fromSequenceNumber,
maxMessages: maxMessages,
sessionId: SessionId,
cancellationToken: cancellationToken);
await foreach (ServiceBusMessage msg in ret.ConfigureAwait(false))
{
yield return(msg);
}
}
private async Task <IEnumerable <T> > ConvertBlobs(IAsyncEnumerable <BlobItem> blobItems, BlobContainerClient blobContainerClient)
{
var list = new List <T>();
await foreach (var blobItem in blobItems.ConfigureAwait(false))
{
BlobBaseClient src = null;
switch (blobItem.Properties.BlobType)
{
case BlobType.Block:
src = blobContainerClient.GetBlockBlobClient(blobItem.Name);
break;
case BlobType.Append:
src = blobContainerClient.GetAppendBlobClient(blobItem.Name);
break;
case BlobType.Page:
src = blobContainerClient.GetPageBlobClient(blobItem.Name);
break;
default:
throw new InvalidOperationException($"Unexpected blob type {blobItem.Properties.BlobType}");
}
var funcCtx = new FunctionBindingContext(Guid.Empty, CancellationToken.None);
var valueCtx = new ValueBindingContext(funcCtx, CancellationToken.None);
var converted = await _converter(src, null, valueCtx).ConfigureAwait(false);
list.Add(converted);
}
return(list);
}
public static Task <int?> MinAsync(this IAsyncEnumerable <int?> source, CancellationToken token = default)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
return(Core());
async Task <int?> Core()
{
token.ThrowIfCancellationRequested();
int?min = default;
foreach await(var item in source.ConfigureAwait(false))
{
token.ThrowIfCancellationRequested();
if (!min.HasValue || item < min)
{
min = item;
}
}
return(min);
}
}
/// <summary>
/// Maps the <see cref="IAsyncEnumerable{TSource}"/> into <see cref="IAsyncEnumerable{TDestination}"/>.
/// </summary>
/// <typeparam name="TSource">The type of the source objects.</typeparam>
/// <typeparam name="TDestination">The type of the destination objects.</typeparam>
/// <param name="mapper">The mapper.</param>
/// <param name="source">The source asynchronous enumerable.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>An <see cref="IAsyncEnumerable{TDestination}"/> collection.</returns>
/// <exception cref="ArgumentNullException">The <paramref name="mapper"/> or <paramref name="source"/> is
/// <c>null</c>.</exception>
public static async IAsyncEnumerable <TDestination> MapAsyncEnumerable <TSource, TDestination>(
this IAsyncMapper <TSource, TDestination> mapper,
IAsyncEnumerable <TSource> source,
[EnumeratorCancellation] CancellationToken cancellationToken = default)
where TDestination : new()
{
if (mapper is null)
{
throw new ArgumentNullException(nameof(mapper));
}
if (source is null)
{
throw new ArgumentNullException(nameof(source));
}
await foreach (var sourceItem in source.ConfigureAwait(false).WithCancellation(cancellationToken))
{
var destinationItem = Factory <TDestination> .CreateInstance();
await mapper.MapAsync(sourceItem, destinationItem).ConfigureAwait(false);
yield return(destinationItem);
}
}
/// <summary>
/// Transform a sequence of bytes with a length prefix into a sequence of byte arrays.
/// </summary>
public static async IAsyncEnumerable <byte[]> ToArraysFromBytesWithLengthPrefix(this IAsyncEnumerable <byte> source)
{
ArgumentNullException.ThrowIfNull(source);
int length = -1;
using MemoryStream ms = new();
await foreach (byte b in source.ConfigureAwait(false))
{
ms.WriteByte(b);
if (length == -1 && ms.Position == 4)
{
length = DecodeMessageLength(ms);
ms.SetLength(0);
}
else if (length == ms.Length)
{
yield return(ms.ToArray()); // array copy
length = -1;
ms.SetLength(0);
}
}
if (ms.Position != 0)
{
throw new InvalidDataException("ToArraysFromBytesWithLengthPrefix: invalid termination.");
}
}
public static IAsyncEnumerable <T> Where <T>(this IAsyncEnumerable <T> source, Func <T, Task <bool> > predicate)
{
if (source == null)
{
throw new ArgumentNullException(nameof(source));
}
if (predicate == null)
{
throw new ArgumentNullException(nameof(predicate));
}
#if CSHARP8
return(Iterator());
async IAsyncEnumerable <T> Iterator()
{
foreach await(var item in source.ConfigureAwait(false))
{
if (await predicate(item).ConfigureAwait(false))
{
yield return(item);
}
}
}
#elif MONADIC
return(source.SelectMany(async x => await predicate(x).ConfigureAwait(false) ? Return(x) : Empty <T>()));
#else
return(new WhereAsyncIteratorWithAsyncPredicate <T>(source, predicate));
#endif
}
private static async IAsyncEnumerable <string> Greet(IAsyncEnumerable <string> names, string greet)
{
await foreach (var i in names.ConfigureAwait(false))
{
yield return(greet + " " + i + "!");
}
}
private async Task <UpgradeStep?> GetNextStepInternalAsync(IAsyncEnumerable <UpgradeStep> steps, IUpgradeContext context, CancellationToken token)
{
if (context is null)
{
throw new ArgumentNullException(nameof(context));
}
// This iterates through all incomplete steps, returning children before parents but initializing parents before children.
// This is intentional because the expectation is that parents are initialized before children, but children are applied before parents.
//
// For each step, the expected order of operations is:
// 1. Initialize the step
// 2. Recurse into sub-steps (if needed)
// 3. Return the step if it's not completed, or
// continue iterating with the next step if it is.
await foreach (var step in steps.ConfigureAwait(false))
{
token.ThrowIfCancellationRequested();
if (step.Status == UpgradeStepStatus.Unknown)
{
// It is not necessary to iterate through sub-steps because parents steps are
// expected to initialize their children during their own initialization
_logger.LogInformation("Initializing upgrade step {StepTitle}", step.Title);
await step.InitializeAsync(context, token).ConfigureAwait(false);
// This is actually not dead code. The above sentence InitializeAsync(...) call will potentially change the status.
#pragma warning disable CA1508 // Avoid dead conditional code
if (step.Status == UpgradeStepStatus.Unknown)
#pragma warning restore CA1508 // Avoid dead conditional code
{
_logger.LogError("Upgrade step initialization failed for step {StepTitle}", step.Title);
throw new InvalidOperationException($"Step must not have unknown status after initialization. Step: {step.Title}");
}
else
{
_logger.LogDebug("Step {StepTitle} initialized", step.Title);
}
}
if (step.SubSteps.Any())
{
var applicableSubSteps = GetStepsForContextAsync(context, step.SubSteps);
var nextSubStep = await GetNextStepInternalAsync(applicableSubSteps, context, token).ConfigureAwait(false);
if (nextSubStep is not null)
{
return(nextSubStep);
}
}
if (!step.IsDone)
{
return(step);
}
}
return(null);
}
private static async IAsyncEnumerable <object> ConvertEnumerable <T>(
IAsyncEnumerable <T> enumerable)
{
await foreach (T item in enumerable.ConfigureAwait(false))
{
yield return(item);
}
}
// This method exists, because we have to put ConfigureAwait(false) on IAsyncEnumerable.
public static async Task <T?> FirstOrDefaultAsync <T>(this IAsyncEnumerable <T> enumerable)
{
await foreach (var item in enumerable.ConfigureAwait(false))
{
return(item);
}
return(default);
public static async Task <T?> FirstOrDefaultAsync <T>(this IAsyncEnumerable <T> enumerable)
where T : class
{
await foreach (var current in enumerable.ConfigureAwait(false))
{
return(current);
}
return(default);
public AsyncEnumerableCollection(
IAsyncEnumerable <T> valueEnumerable,
CancellationToken cancellation = default)
{
_enumerator = valueEnumerable
.ConfigureAwait(true)
.WithCancellation(cancellation)
.GetAsyncEnumerator();
}
public static async Task <TElement> FirstOrDefault <TElement>(this IAsyncEnumerable <TElement> elements)
where TElement : class, IAsyncListElement
{
await foreach (var element in elements.ConfigureAwait(false))
{
return(element);
}
return(default);
public static async IAsyncEnumerable <Illust> R18(this IAsyncEnumerable <Illust> source)
{
await foreach (var i in source.ConfigureAwait(false))
{
if (i.IsR18)
{
yield return(i);
}
}
}
private static async IAsyncEnumerable <object?> MapAsyncEnumerableInternal <T>(IAsyncEnumerable <T> asyncEnumerable)
{
if (asyncEnumerable is not null)
{
await foreach (var item in asyncEnumerable.ConfigureAwait(false))
{
yield return(item);
}
}
}
public static async Task <TElement> First <TElement>(this IAsyncEnumerable <TElement> elements)
where TElement : class, IAsyncListElement
{
await foreach (var element in elements.ConfigureAwait(false))
{
return(element);
}
throw new InvalidOperationException("Message List was empty, or timed out");
}
public static async ValueTask <Dictionary <TKey, TValue> > ToDictionaryAsync <T, TKey, TValue>(this IAsyncEnumerable <T> source, Func <T, TKey> keySelector, Func <T, TValue> valueSelector)
{
var result = new Dictionary <TKey, TValue>();
await foreach (var item in source.ConfigureAwait(false))
{
result.Add(keySelector(item), valueSelector(item));
}
return(result);
}
public static async ValueTask <List <T> > ToListAsync <T>(this IAsyncEnumerable <T> source)
{
var list = new List <T>();
await foreach (var item in source.ConfigureAwait(false))
{
list.Add(item);
}
return(list);
}
public static async ValueTask <int> CountAsync <T>(this IAsyncEnumerable <T> source)
{
int count = 0;
await foreach (var item in source.ConfigureAwait(false))
{
count++;
}
return(count);
}
async static ValueTask <T[]> ToArrayAsync <T>(IAsyncEnumerable <T> source)
{
var list = new List <T>();
await foreach (var item in source.ConfigureAwait(false))
{
list.Add(item);
}
return(list.ToArray());
}
/// <inheritdoc />
public async IAsyncEnumerable <T> Populate <T>(IAsyncEnumerable <T> entities, byte[] body)
{
var json = Encoding.UTF8.GetString(body);
await foreach (var entity in entities.ConfigureAwait(false))
{
JsonConvert.PopulateObject(json, entity, SerializerSettings);
yield return(entity);
}
}
public static async Task <ImmutableArray <T> > ToImmutableArrayAsync <T>(this IAsyncEnumerable <T> values)
{
using var _ = ArrayBuilder <T> .GetInstance(out var result);
await foreach (var value in values.ConfigureAwait(false))
{
result.Add(value);
}
return(result.ToImmutable());
}
public static async Task <List <T> > ToListAsync <T>(this IAsyncEnumerable <T> source)
{
var result = new List <T>();
await foreach (var i in source.ConfigureAwait(false))
{
result.Add(i);
}
return(result);
}
public static async IAsyncEnumerable <TValue> GetManyAsync <TKey, TValue>(
this IAsyncKeyResolver <TKey, TValue> cache,
IAsyncEnumerable <TKey> keys,
[EnumeratorCancellation] CancellationToken cancellationToken = default)
where TKey : notnull
{
await foreach (var key in keys.ConfigureAwait(false))
{
yield return(await cache.GetAsync(key, cancellationToken).ConfigureAwait(false));
}
}
public static async IAsyncEnumerable <T> TakeAsync <T>(this IAsyncEnumerable <T> source, int count)
{
await foreach (var item in source.ConfigureAwait(false))
{
if (count > 0)
{
count--;
yield return(item);
}
}
}
public static async Task <IList <T> > ToListAsync <T>(this IAsyncEnumerable <T> items)
{
List <T> output = new List <T>();
await foreach (var item in items.ConfigureAwait(false))
{
output.Add(item);
}
return(output);
}
internal static async Task <List <T> > ToListAsync <T>(this IAsyncEnumerable <T> items)
{
var results = new List <T>();
await foreach (var item in items
.ConfigureAwait(false))
{
results.Add(item);
}
return(results);
}
public static async Task CopyToAsync(
this IAsyncEnumerable <StreamPartition> partitions,
Stream destination,
bool async,
CancellationToken cancellationToken)
{
var destinationOffset = destination.Position;
await foreach (StreamPartition partition in partitions.ConfigureAwait(false))
{
if (async)
{
await copyCore(partition).ConfigureAwait(false);
}
else
{
copyCore(partition).EnsureCompleted();
}
}
async Task copyCore(StreamPartition partition)
{
// if the destination is seekable, ensure we position it correctly,
// else we trust the partitions are received in order and just write
// blindly
if (destination.CanSeek)
{
destination.Position = partition.ParentPosition;
}
else
{
Debug.Assert(
partition.ParentPosition == destination.Position - destinationOffset,
"Stream partitions received out of order for a non-seekable stream."
);
}
if (async)
{
await
partition
.CopyToAsync(destination, Constants.DefaultBufferSize, cancellationToken)
.ConfigureAwait(false)
;
}
else
{
partition.CopyTo(destination, Constants.DefaultBufferSize);
}
partition.Dispose();
}
}
public static async Task <IEnumerable <T> > AsTask <T>(this IAsyncEnumerable <T> asyncEnumerable)
{
// TODO:
var list = new List <T>();
await foreach (var value in asyncEnumerable.ConfigureAwait(false))
{
list.Add(value);
}
return(list);
}