Merge branch 'master' into orleans3

# Conflicts:
#	src/Squidex/Squidex.csproj

src/Squidex.Infrastructure.MongoDb/EventSourcing/MongoEventStore_Reader.cs

@@ -7,7 +7,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Reactive.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using MongoDB.Driver;
@@ -87,9 +86,9 @@ namespace Squidex.Infrastructure.EventSourcing
             return QueryAsync(callback, lastPosition, filter, ct);
         }
 
-        private async Task QueryAsync(Func<StoredEvent, Task> callback, StreamPosition lastPosition, FilterDefinition<MongoEventCommit> filter, CancellationToken ct)
+        private Task QueryAsync(Func<StoredEvent, Task> callback, StreamPosition lastPosition, FilterDefinition<MongoEventCommit> filter, CancellationToken ct)
         {
-            await Collection.Find(filter).Sort(Sort.Ascending(TimestampField)).ForEachAsync(async commit =>
+            return Collection.Find(filter).Sort(Sort.Ascending(TimestampField)).ForEachPipelineAsync(async commit =>
             {
                 var eventStreamOffset = (int)commit.EventStreamOffset;
 

src/Squidex.Infrastructure.MongoDb/MongoDb/MongoExtensions.cs

@@ -7,7 +7,9 @@
 
 using System;
 using System.Linq.Expressions;
+using System.Threading;
 using System.Threading.Tasks;
+using System.Threading.Tasks.Dataflow;
 using MongoDB.Bson;
 using MongoDB.Driver;
 using Squidex.Infrastructure.States;
@@ -128,5 +130,51 @@ namespace Squidex.Infrastructure.MongoDb
                 }
             }
         }
+
+        public static async Task ForEachPipelineAsync<TDocument>(this IAsyncCursorSource<TDocument> source, Func<TDocument, Task> processor, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            var cursor = await source.ToCursorAsync(cancellationToken);
+
+            await cursor.ForEachPipelineAsync(processor, cancellationToken);
+        }
+
+        public static async Task ForEachPipelineAsync<TDocument>(this IAsyncCursor<TDocument> source, Func<TDocument, Task> processor, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            var actionBlock =
+                new ActionBlock<TDocument>(processor,
+                    new ExecutionDataflowBlockOptions
+                    {
+                        MaxDegreeOfParallelism = 1,
+                        MaxMessagesPerTask = 1,
+                        BoundedCapacity = 100
+                    });
+
+            using (var selfToken = new CancellationTokenSource())
+            {
+                using (var combined = CancellationTokenSource.CreateLinkedTokenSource(selfToken.Token, cancellationToken))
+                {
+                    try
+                    {
+                        await source.ForEachAsync(async i =>
+                        {
+                            if (!await actionBlock.SendAsync(i, combined.Token))
+                            {
+                                selfToken.Cancel();
+                            }
+                        }, combined.Token);
+
+                        actionBlock.Complete();
+                    }
+                    catch (Exception ex)
+                    {
+                        ((IDataflowBlock)actionBlock).Fault(ex);
+                    }
+                    finally
+                    {
+                        await actionBlock.Completion;
+                    }
+                }
+            }
+        }
     }
 }

src/Squidex.Infrastructure.MongoDb/Squidex.Infrastructure.MongoDb.csproj

@@ -15,6 +15,7 @@
     <PackageReference Include="MongoDB.Driver" Version="2.5.0" />
     <PackageReference Include="RefactoringEssentials" Version="5.6.0" />
     <PackageReference Include="StyleCop.Analyzers" Version="1.0.2" />
+    <PackageReference Include="System.Threading.Tasks.Dataflow" Version="4.8.0" />
     <PackageReference Include="System.ValueTuple" Version="4.4.0" />
   </ItemGroup>
   <PropertyGroup>

tests/Squidex.Infrastructure.Tests/MongoDb/MongoExtensionsTests.cs

@@ -0,0 +1,161 @@
+// ==========================================================================
+//  Squidex Headless CMS
+// ==========================================================================
+//  Copyright (c) Squidex UG (haftungsbeschraenkt)
+//  All rights reserved. Licensed under the MIT license.
+// ==========================================================================
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using MongoDB.Driver;
+using Squidex.Infrastructure.Tasks;
+using Xunit;
+
+namespace Squidex.Infrastructure.MongoDb
+{
+    public class MongoExtensionsTests
+    {
+        public sealed class Cursor<T> : IAsyncCursor<T>
+        {
+            private readonly List<object> items = new List<object>();
+            private int index = -1;
+
+            public IEnumerable<T> Current
+            {
+                get
+                {
+                    if (items[index] is Exception ex)
+                    {
+                        throw ex;
+                    }
+
+                    return Enumerable.Repeat((T)items[index], 1);
+                }
+            }
+
+            public Cursor<T> Add(T item)
+            {
+                items.Add(item);
+
+                return this;
+            }
+
+            public Cursor<T> Add(Exception ex)
+            {
+                items.Add(ex);
+
+                return this;
+            }
+
+            public void Dispose()
+            {
+            }
+
+            public bool MoveNext(CancellationToken cancellationToken = default(CancellationToken))
+            {
+                index++;
+
+                return index < items.Count;
+            }
+
+            public async Task<bool> MoveNextAsync(CancellationToken cancellationToken = default(CancellationToken))
+            {
+                await Task.Delay(1, cancellationToken);
+
+                return MoveNext(cancellationToken);
+            }
+        }
+
+        [Fact]
+        public async Task Should_enumerate_over_items()
+        {
+            var result = new List<int>();
+
+            var cursor = new Cursor<int>().Add(0).Add(1).Add(1).Add(2).Add(3).Add(5);
+
+            await cursor.ForEachPipelineAsync(x =>
+            {
+                result.Add(x);
+                return TaskHelper.Done;
+            });
+
+            Assert.Equal(new List<int> { 0, 1, 1, 2, 3, 5 }, result);
+        }
+
+        [Fact]
+        public async Task Should_break_when_cursor_failed()
+        {
+            var ex = new InvalidOperationException();
+
+            var result = new List<int>();
+
+            var cursor = new Cursor<int>().Add(0).Add(1).Add(1).Add(ex).Add(2).Add(3).Add(5);
+
+            await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            {
+                return cursor.ForEachPipelineAsync(x =>
+                {
+                    result.Add(x);
+                    return TaskHelper.Done;
+                });
+            });
+
+            Assert.Equal(new List<int> { 0, 1, 1 }, result);
+        }
+
+        [Fact]
+        public async Task Should_break_when_handler_failed()
+        {
+            var ex = new InvalidOperationException();
+
+            var result = new List<int>();
+
+            var cursor = new Cursor<int>().Add(0).Add(1).Add(1).Add(2).Add(3).Add(5);
+
+            await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            {
+                return cursor.ForEachPipelineAsync(x =>
+                {
+                    if (x == 2)
+                    {
+                        throw ex;
+                    }
+
+                    result.Add(x);
+                    return TaskHelper.Done;
+                });
+            });
+
+            Assert.Equal(new List<int> { 0, 1, 1 }, result);
+        }
+
+        [Fact]
+        public async Task Should_stop_when_cancelled1()
+        {
+            var cts = new CancellationTokenSource();
+
+            var result = new List<int>();
+
+            var cursor = new Cursor<int>().Add(0).Add(1).Add(1).Add(2).Add(3).Add(5);
+
+            await Assert.ThrowsAsync<TaskCanceledException>(() =>
+            {
+                return cursor.ForEachPipelineAsync(x =>
+                {
+                    if (x == 2)
+                    {
+                        cts.Cancel();
+                    }
+
+                    result.Add(x);
+                    return TaskHelper.Done;
+                }, cts.Token);
+            });
+
+            Assert.Equal(new List<int> { 0, 1, 1, 2 }, result);
+        }
+    }
+}