Cut up Core into something we can use

src/BinaryPatchUtility.cs

@@ -4,7 +4,7 @@ using Ionic.BZip2;
 
 // Adapted from https://github.com/LogosBible/bsdiff.net/blob/master/src/bsdiff/BinaryPatchUtility.cs
 
-namespace Squirrel.Core
+namespace Squirrel
 {
     /*
     The original bsdiff.c source code (http://www.daemonology.net/bsdiff/) is

src/ContentType.cs

@@ -2,7 +2,7 @@ using System;
 using System.Linq;
 using System.Xml;
 
-namespace Squirrel.Core
+namespace Squirrel
 {
     internal static class ContentType
     {
@@ -25,16 +25,21 @@ namespace Squirrel.Core
                     k.GetAttribute("Extension").ToLowerInvariant(),
                     k.GetAttribute("ContentType").ToLowerInvariant()));
 
-            elements
+            var toAdd = elements
                 .Where(x => existingTypes.All(t => t.Item2 != x.Item2.ToLowerInvariant()))
                 .Select(element => {
                     var ret = doc.CreateElement(element.Item1, typesElement.NamespaceURI);
+
                     var ext = doc.CreateAttribute("Extension"); ext.Value = element.Item2;
                     var ct = doc.CreateAttribute("ContentType"); ct.Value = element.Item3;
-                    new[] { ext, ct }.ForEach(x => ret.Attributes.Append(x));
+
+                    ret.Attributes.Append(ext);
+                    ret.Attributes.Append(ct);
 
                     return ret;
-                }).ForEach(x => typesElement.AppendChild(x));
+                });
+
+            foreach (var v in toAdd) typesElement.AppendChild(v);
         }
     }
 }

src/DeltaPackage.cs

@@ -6,9 +6,9 @@ using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 using Ionic.Zip;
-using ReactiveUIMicro;
+using Splat;
 
-namespace Squirrel.Core
+namespace Squirrel
 {
     public interface IDeltaPackageBuilder
     {
@@ -69,8 +69,9 @@ namespace Squirrel.Core
 
                 var newLibDir = tempInfo.GetDirectories().First(x => x.Name.ToLowerInvariant() == "lib");
 
-                newLibDir.GetAllFilesRecursively()
+                foreach (var libFile in newLibDir.GetAllFilesRecursively()) {
-                    .ForEach(libFile => createDeltaForSingleFile(libFile, tempInfo, baseLibFiles));
+                    createDeltaForSingleFile(libFile, tempInfo, baseLibFiles);
+                }
 
                 ReleasePackage.addDeltaFilesToContentTypes(tempInfo.FullName);
 

src/EnumerableExtensions.cs

@@ -0,0 +1,281 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt
+
+using System.Collections.Generic;
+
+namespace System.Linq
+{
+    internal static class EnumerableExtensions
+    {
+        /// <summary>
+        /// Enumerates the sequence and invokes the given action for each value in the sequence.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="onNext">Action to invoke for each element.</param>
+        public static void ForEach<TSource>(this IEnumerable<TSource> source, Action<TSource> onNext)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (onNext == null)
+                throw new ArgumentNullException("onNext");
+
+            foreach (var item in source) onNext(item);
+        }
+
+        /// <summary>
+        /// Returns the elements with the maximum key value by using the default comparer to compare key values.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <typeparam name="TKey">Key type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="keySelector">Key selector used to extract the key for each element in the sequence.</param>
+        /// <returns>List with the elements that share the same maximum key value.</returns>
+        public static IList<TSource> MaxBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (keySelector == null)
+                throw new ArgumentNullException("keySelector");
+
+            return MaxBy(source, keySelector, Comparer<TKey>.Default);
+        }
+
+        /// <summary>
+        /// Returns the elements with the minimum key value by using the specified comparer to compare key values.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <typeparam name="TKey">Key type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="keySelector">Key selector used to extract the key for each element in the sequence.</param>
+        /// <param name="comparer">Comparer used to determine the maximum key value.</param>
+        /// <returns>List with the elements that share the same maximum key value.</returns>
+        public static IList<TSource> MaxBy<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, IComparer<TKey> comparer)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (keySelector == null)
+                throw new ArgumentNullException("keySelector");
+            if (comparer == null)
+                throw new ArgumentNullException("comparer");
+
+            return ExtremaBy(source, keySelector, (key, minValue) => comparer.Compare(key, minValue));
+        }
+
+        private static IList<TSource> ExtremaBy<TSource, TKey>(IEnumerable<TSource> source, Func<TSource, TKey> keySelector, Func<TKey, TKey, int> compare)
+        {
+            var result = new List<TSource>();
+
+            using (var e = source.GetEnumerator())
+            {
+                if (!e.MoveNext())
+                    throw new InvalidOperationException("Source sequence doesn't contain any elements.");
+
+                var current = e.Current;
+                var resKey = keySelector(current);
+                result.Add(current);
+
+                while (e.MoveNext())
+                {
+                    var cur = e.Current;
+                    var key = keySelector(cur);
+
+                    var cmp = compare(key, resKey);
+                    if (cmp == 0)
+                    {
+                        result.Add(cur);
+                    }
+                    else if (cmp > 0)
+                    {
+                        result = new List<TSource> { cur };
+                        resKey = key;
+                    }
+                }
+            }
+
+            return result;
+        }
+
+        /// <summary>
+        /// Lazily invokes an action for each value in the sequence.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="onNext">Action to invoke for each element.</param>
+        /// <returns>Sequence exhibiting the specified side-effects upon enumeration.</returns>
+        public static IEnumerable<TSource> Do<TSource>(this IEnumerable<TSource> source, Action<TSource> onNext)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (onNext == null)
+                throw new ArgumentNullException("onNext");
+
+            return DoHelper(source, onNext, _ => { }, () => { });
+        }
+
+        /// <summary>
+        /// Lazily invokes an action for each value in the sequence, and executes an action for successful termination.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="onNext">Action to invoke for each element.</param>
+        /// <param name="onCompleted">Action to invoke on successful termination of the sequence.</param>
+        /// <returns>Sequence exhibiting the specified side-effects upon enumeration.</returns>
+        public static IEnumerable<TSource> Do<TSource>(this IEnumerable<TSource> source, Action<TSource> onNext, Action onCompleted)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (onNext == null)
+                throw new ArgumentNullException("onNext");
+            if (onCompleted == null)
+                throw new ArgumentNullException("onCompleted");
+
+            return DoHelper(source, onNext, _ => { }, onCompleted);
+        }
+
+        /// <summary>
+        /// Lazily invokes an action for each value in the sequence, and executes an action upon exceptional termination.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="onNext">Action to invoke for each element.</param>
+        /// <param name="onError">Action to invoke on exceptional termination of the sequence.</param>
+        /// <returns>Sequence exhibiting the specified side-effects upon enumeration.</returns>
+        public static IEnumerable<TSource> Do<TSource>(this IEnumerable<TSource> source, Action<TSource> onNext, Action<Exception> onError)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (onNext == null)
+                throw new ArgumentNullException("onNext");
+            if (onError == null)
+                throw new ArgumentNullException("onError");
+
+            return DoHelper(source, onNext, onError, () => { });
+        }
+
+        /// <summary>
+        /// Lazily invokes an action for each value in the sequence, and executes an action upon successful or exceptional termination.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="onNext">Action to invoke for each element.</param>
+        /// <param name="onError">Action to invoke on exceptional termination of the sequence.</param>
+        /// <param name="onCompleted">Action to invoke on successful termination of the sequence.</param>
+        /// <returns>Sequence exhibiting the specified side-effects upon enumeration.</returns>
+        public static IEnumerable<TSource> Do<TSource>(this IEnumerable<TSource> source, Action<TSource> onNext, Action<Exception> onError, Action onCompleted)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (onNext == null)
+                throw new ArgumentNullException("onNext");
+            if (onError == null)
+                throw new ArgumentNullException("onError");
+            if (onCompleted == null)
+                throw new ArgumentNullException("onCompleted");
+
+            return DoHelper(source, onNext, onError, onCompleted);
+        }
+
+        private static IEnumerable<TSource> DoHelper<TSource>(this IEnumerable<TSource> source, Action<TSource> onNext, Action<Exception> onError, Action onCompleted)
+        {
+            using (var e = source.GetEnumerator())
+            {
+                while (true)
+                {
+                    var current = default(TSource);
+                    try
+                    {
+                        if (!e.MoveNext())
+                            break;
+
+                        current = e.Current;
+                    }
+                    catch (Exception ex)
+                    {
+                        onError(ex);
+                        throw;
+                    }
+
+                    onNext(current);
+                    yield return current;
+                }
+
+                onCompleted();
+            }
+        }
+
+        /// <summary>
+        /// Returns the source sequence prefixed with the specified value.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="values">Values to prefix the sequence with.</param>
+        /// <returns>Sequence starting with the specified prefix value, followed by the source sequence.</returns>
+        public static IEnumerable<TSource> StartWith<TSource>(this IEnumerable<TSource> source, params TSource[] values)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+
+            return source.StartWith_(values);
+        }
+
+        static IEnumerable<TSource> StartWith_<TSource>(this IEnumerable<TSource> source, params TSource[] values)
+        {
+            foreach (var x in values)
+                yield return x;
+
+            foreach (var item in source)
+                yield return item;
+        }
+
+        /// <summary>
+        /// Returns elements with a distinct key value by using the default equality comparer to compare key values.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <typeparam name="TKey">Key type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="keySelector">Key selector.</param>
+        /// <returns>Sequence that contains the elements from the source sequence with distinct key values.</returns>
+        public static IEnumerable<TSource> Distinct<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (keySelector == null)
+                throw new ArgumentNullException("keySelector");
+
+            return source.Distinct_(keySelector, EqualityComparer<TKey>.Default);
+        }
+
+        /// <summary>
+        /// Returns elements with a distinct key value by using the specified equality comparer to compare key values.
+        /// </summary>
+        /// <typeparam name="TSource">Source sequence element type.</typeparam>
+        /// <typeparam name="TKey">Key type.</typeparam>
+        /// <param name="source">Source sequence.</param>
+        /// <param name="keySelector">Key selector.</param>
+        /// <param name="comparer">Comparer used to compare key values.</param>
+        /// <returns>Sequence that contains the elements from the source sequence with distinct key values.</returns>
+        public static IEnumerable<TSource> Distinct<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
+        {
+            if (source == null)
+                throw new ArgumentNullException("source");
+            if (keySelector == null)
+                throw new ArgumentNullException("keySelector");
+            if (comparer == null)
+                throw new ArgumentNullException("comparer");
+
+            return source.Distinct_(keySelector, comparer);
+        }
+
+        static IEnumerable<TSource> Distinct_<TSource, TKey>(this IEnumerable<TSource> source, Func<TSource, TKey> keySelector, IEqualityComparer<TKey> comparer)
+        {
+            var set = new HashSet<TKey>(comparer);
+
+            foreach (var item in source)
+            {
+                var key = keySelector(item);
+                if (set.Add(key))
+                    yield return item;
+            }
+        }
+    }
+}

src/PackageExtensions.cs

@@ -0,0 +1,17 @@
+using System;
+using NuGet;
+
+namespace Squirrel
+{
+    public static class PackageExtensions
+    {
+        public static string ExtractTitle(this IPackage package)
+        {
+            if (package == null)
+                return String.Empty;
+
+            var title = package.Title;
+            return !String.IsNullOrWhiteSpace(title) ? title : package.Id;
+        }
+    }
+}

src/ReleaseEntry.cs

@@ -3,15 +3,15 @@ using System.Collections.Generic;
 using System.Diagnostics.Contracts;
 using System.IO;
 using System.Linq;
-using System.Reactive.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
 using NuGet;
-using ReactiveUIMicro;
+using Splat;
-using Squirrel.Core.Extensions;
 using System.Runtime.Serialization;
+using System.Threading.Tasks;
+using System.Collections.Concurrent;
 
-namespace Squirrel.Core
+namespace Squirrel
 {
     public interface IReleaseEntry
     {
@@ -150,25 +150,24 @@ namespace Squirrel.Core
             }
         }
 
-        public static void BuildReleasesFile(string releasePackagesDir, IFileSystemFactory fileSystemFactory = null)
+        public static void BuildReleasesFile(string releasePackagesDir)
         {
-            fileSystemFactory = fileSystemFactory ?? AnonFileSystem.Default;
+            var packagesDir = new DirectoryInfo(releasePackagesDir);
-            var packagesDir = fileSystemFactory.GetDirectoryInfo(releasePackagesDir);
 
             // Generate release entries for all of the local packages
-            var entries = packagesDir.GetFiles("*.nupkg").MapReduce(x => Observable.Start(() => {
+            var entriesQueue = new ConcurrentQueue<ReleaseEntry>();
+            Parallel.ForEach(packagesDir.GetFiles("*.nupkg"), x => {
                 using (var file = x.OpenRead()) {
-                    return GenerateFromFile(file, x.Name);
+                    entriesQueue.Enqueue(GenerateFromFile(file, x.Name));
                 }
-            }, RxApp.TaskpoolScheduler)).First();
+            });
 
             // Write the new RELEASES file to a temp file then move it into
             // place
-            var tempFile = fileSystemFactory.CreateTempFile();
+            var entries = entriesQueue.ToList();
-            try {
+            var tempFile = Path.GetTempFileName();
-                if (entries.Count > 0) WriteReleaseFile(entries, tempFile.Item2);
+            using (var of = File.OpenWrite(tempFile)) {
-            } finally {
+                if (entries.Count > 0) WriteReleaseFile(entries, of);
-                tempFile.Item2.Dispose();
             }
 
             var target = Path.Combine(packagesDir.FullName, "RELEASES");
@@ -176,7 +175,7 @@ namespace Squirrel.Core
                 File.Delete(target);
             }
 
-            fileSystemFactory.GetFileInfo(tempFile.Item1).MoveTo(target);
+            File.Move(tempFile, target);
         }
 
         static bool filenameIsDeltaFile(string filename)

src/ReleaseExtensions.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
+
+namespace Squirrel
+{
+    public static class VersionExtensions
+    {
+        public static Version ToVersion(this IReleasePackage package)
+        {
+            return package.InputPackageFile.ToVersion();
+        }
+
+        public static Version ToVersion(this string fileName)
+        {
+            var parts = (new FileInfo(fileName)).Name
+                    .Replace(".nupkg", "").Replace("-delta", "")
+                    .Split('.', '-').Reverse();
+
+            var numberRegex = new Regex(@"^\d+$");
+
+            var versionFields = parts
+                .Where(x => numberRegex.IsMatch(x))
+                .Select(Int32.Parse)
+                .Reverse()
+                .ToArray();
+
+            if (versionFields.Length < 2 || versionFields.Length > 4)
+            {
+                return null;
+            }
+
+            switch (versionFields.Length)
+            {
+            case 2:
+                return new Version(versionFields[0], versionFields[1]);
+            case 3:
+                return new Version(versionFields[0], versionFields[1], versionFields[2]);
+            case 4:
+                return new Version(versionFields[0], versionFields[1], versionFields[2], versionFields[3]);
+            }
+
+            return null;
+        }
+    }
+}

src/ReleasePackage.cs

@@ -11,10 +11,9 @@ using System.Text.RegularExpressions;
 using System.Xml;
 using Ionic.Zip;
 using NuGet;
-using ReactiveUIMicro;
+using Splat;
-using Squirrel.Core.Extensions;
 
-namespace Squirrel.Core
+namespace Squirrel
 {
     internal static class FrameworkTargetVersion
     {

src/Utility.cs

@@ -4,21 +4,18 @@ using System.ComponentModel;
 using System.Diagnostics.Contracts;
 using System.IO;
 using System.Linq;
-using System.Reactive;
-using System.Reactive.Concurrency;
-using System.Reactive.Disposables;
-using System.Reactive.Linq;
-using System.Reactive.Subjects;
 using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Security.AccessControl;
 using System.Security.Cryptography;
 using System.Security.Principal;
 using System.Threading;
-using ReactiveUIMicro;
+using Splat;
 using System.Text;
+using System.Threading.Tasks;
+using System.Collections.Concurrent;
 
-namespace Squirrel.Core
+namespace Squirrel
 {
     public static class Utility
     {
@@ -58,7 +55,7 @@ namespace Squirrel.Core
             }
         }
 
-        public static IObservable<Unit> CopyToAsync(string from, string to)
+        public static async Task CopyToAsync(string from, string to)
         {
             Contract.Requires(!String.IsNullOrEmpty(from) && File.Exists(from));
             Contract.Requires(!String.IsNullOrEmpty(to));
@@ -67,11 +64,11 @@ namespace Squirrel.Core
                 Log().Warn("The file {0} does not exist", from);
 
                 // TODO: should we fail this operation?
-                return Observable.Return(Unit.Default);
+                return;
             }
 
             // XXX: SafeCopy
-            return Observable.Start(() => File.Copy(from, to, true), RxApp.TaskpoolScheduler);
+            await Task.Run(() => File.Copy(from, to, true));
         }
 
         public static void Retry(this Action block, int retries = 2)
@@ -105,14 +102,20 @@ namespace Squirrel.Core
             }
         }
 
-        public static IObservable<IList<TRet>> MapReduce<T, TRet>(this IObservable<T> This, Func<T, IObservable<TRet>> selector, int degreeOfParallelism = 4)
+        public static Task ForEachAsync<T>(this IEnumerable<T> source, Action<T> body, int degreeOfParallelism = 4)
         {
-            return This.Select(x => Observable.Defer(() => selector(x))).Merge(degreeOfParallelism).ToList();
+            return ForEachAsync(source, x => Task.Run(() => body(x)), degreeOfParallelism);
         }
 
-        public static IObservable<IList<TRet>> MapReduce<T, TRet>(this IEnumerable<T> This, Func<T, IObservable<TRet>> selector, int degreeOfParallelism = 4)
+        public static Task ForEachAsync<T>(this IEnumerable<T> source, Func<T, Task> body, int degreeOfParallelism = 4)
         {
-            return This.ToObservable().Select(x => Observable.Defer(() => selector(x))).Merge(degreeOfParallelism).ToList();
+            return Task.WhenAll(
+                from partition in Partitioner.Create(source).GetPartitions(degreeOfParallelism)
+                select Task.Run(async () => {
+                    using (partition)
+                        while (partition.MoveNext())
+                            await body(partition.Current);
+                }));
         }
 
         static string directoryChars;
@@ -147,17 +150,15 @@ namespace Squirrel.Core
                 DeleteDirectory(tempDir.FullName).Wait());
         }
 
-        public static IObservable<Unit> DeleteDirectory(string directoryPath, IScheduler scheduler = null)
+        public static async Task DeleteDirectory(string directoryPath)
         {
             Contract.Requires(!String.IsNullOrEmpty(directoryPath));
 
-            scheduler = scheduler ?? RxApp.TaskpoolScheduler;
-
             Log().Info("Starting to delete folder: {0}", directoryPath);
 
             if (!Directory.Exists(directoryPath)) {
                 Log().Warn("DeleteDirectory: does not exist - {0}", directoryPath);
-                return Observable.Return(Unit.Default);
+                return;
             }
 
             // From http://stackoverflow.com/questions/329355/cannot-delete-directory-with-directory-deletepath-true/329502#329502
@@ -177,23 +178,16 @@ namespace Squirrel.Core
                 Log().Warn(message, ex);
             }
 
-            var fileOperations = files.MapReduce(file =>
+            var fileOperations = files.ForEachAsync(file => {
-                Observable.Start(() => {
-                    Log().Debug("Now deleting file: {0}", file);
                 File.SetAttributes(file, FileAttributes.Normal);
                 File.Delete(file);
-                }, scheduler))
+            });
-            .Select(_ => Unit.Default);
 
             var directoryOperations =
-                dirs.MapReduce(dir => DeleteDirectory(dir, scheduler)
+                dirs.ForEachAsync(async dir => await DeleteDirectory(dir));
-                    .Retry(3))
+
-                    .Select(_ => Unit.Default);
+            await Task.WhenAll(fileOperations, directoryOperations);
 
-            return fileOperations
-                .Merge(directoryOperations, scheduler)
-                .ToList() // still feeling a bit icky
-                .Select(_ => {
             Log().Debug("Now deleting folder: {0}", directoryPath);
             File.SetAttributes(directoryPath, FileAttributes.Normal);
 
@@ -203,8 +197,6 @@ namespace Squirrel.Core
                 var message = String.Format("DeleteDirectory: could not delete - {0}", directoryPath);
                 Log().ErrorException(message, ex);
             }
-                    return Unit.Default;
-                });
         }
 
         public static Tuple<string, Stream> CreateTempFile()
@@ -251,9 +243,11 @@ namespace Squirrel.Core
             Log().Error("safeDeleteFileAtNextReboot: failed - {0} - {1}", name, lastError);
         }
 
-        static IRxUIFullLogger Log()
+        static IFullLogger logger;
+        static IFullLogger Log()
         {
-            return LogManager.GetLogger(typeof(Utility));
+            return logger ??
+                (logger = Locator.CurrentMutable.GetService<ILogManager>().GetLogger(typeof(Utility)));
         }
 
         [DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
@@ -271,6 +265,7 @@ namespace Squirrel.Core
         }
     }
 
+    /*
     public sealed class SingleGlobalInstance : IDisposable
     {
         readonly static object gate = 42;
@@ -331,4 +326,29 @@ namespace Squirrel.Core
             lockScheduler.Dispose();
         }
     }
+    */
+
+    public static class Disposable
+    {
+        public static IDisposable Create(Action action)
+        {
+            return new AnonDisposable(action);
+        }
+
+        class AnonDisposable : IDisposable
+        {
+            static readonly Action dummyBlock = (() => { });
+            Action block;
+
+            public AnonDisposable(Action b)
+            {
+                block = b;
+            }
+
+            public void Dispose()
+            {
+                Interlocked.Exchange(ref block, dummyBlock)();
+            }
+        }
+    }
 }

src/packages.config

@@ -2,4 +2,5 @@
 <packages>
   <package id="Microsoft.Web.Xdt" version="2.1.1" targetFramework="net45" />
   <package id="NuGet.Core" version="2.8.2" targetFramework="net45" />
+  <package id="Splat" version="1.4.0" targetFramework="net45" />
 </packages>