Reuse Task instances where possible (#107)

liquidprojections · Jan 23, 2018 · 107050e · 107050e
1 parent 2bef488
commit 107050e
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Showing 4 changed files with 28 additions and 16 deletions.
diff --git a/Src/LiquidProjections/Dispatcher.cs b/Src/LiquidProjections/Dispatcher.cs
@@ -11,6 +11,8 @@ namespace LiquidProjections
     /// </summary>
     public class Dispatcher
     {
+        private static readonly Task<ExceptionResolution> AbortExceptionResolutionTask = Task.FromResult(ExceptionResolution.Abort);
+
         private readonly CreateSubscription createSubscription;
 
         public Dispatcher(CreateSubscription createSubscription)
@@ -43,9 +45,9 @@ public Dispatcher(CreateSubscription createSubscription)
         /// Configures the behavior of the dispatcher in case an exception is thrown by a subscriber. The default
         /// behavior is to dispose of the subscription.
         /// </summary>
-        public HandleException ExceptionHandler { get; set; } = (e, attempts, info) => Task.FromResult(ExceptionResolution.Abort);
+        public HandleException ExceptionHandler { get; set; } = (e, attempts, info) => AbortExceptionResolutionTask;
 
-        public HandleSuccess SuccessHandler { get; set; } = _ => Task.FromResult(false);
+        public HandleSuccess SuccessHandler { get; set; } = _ => SpecializedTasks.FalseTask;
 
         private async Task HandleTransactions(IReadOnlyList<Transaction> transactions, Func<IReadOnlyList<Transaction>, SubscriptionInfo, Task> handler, SubscriptionInfo info)
         {
@@ -176,6 +178,6 @@ public class SubscriptionOptions
         /// If restarting is enabled through <see cref="RestartWhenAhead"/>, this property can be used to run some
         /// clean-up code before the dispatcher will restart at the first transaction.
         /// </summary>
-        public Func<Task> BeforeRestarting { get; set; } = () => Task.FromResult(0);
+        public Func<Task> BeforeRestarting { get; set; } = () => SpecializedTasks.ZeroTask;
     }
 }
diff --git a/Src/LiquidProjections/EventMapBuilder.cs b/Src/LiquidProjections/EventMapBuilder.cs
@@ -562,7 +562,7 @@ public static class EventMapBuilderExtensions
             eventMappingBuilder.As((anEvent, context) =>
             {
                 action(anEvent, context);
-                return Task.FromResult(0);
+                return SpecializedTasks.ZeroTask;
             });
         }
 
@@ -592,7 +592,7 @@ public static class EventMapBuilderExtensions
             eventMappingBuilder.As((anEvent, context) =>
             {
                 action(anEvent);
-                return Task.FromResult(0);
+                return SpecializedTasks.ZeroTask;
             });
         }
 
@@ -837,7 +837,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent, context);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -867,7 +867,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -926,7 +926,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent, context);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -959,7 +959,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -1020,7 +1020,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent, context);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -1052,7 +1052,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -1113,7 +1113,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent, context);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -1146,7 +1146,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -1207,7 +1207,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent, context);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 
@@ -1239,7 +1239,7 @@ public static class EventMapBuilderExtensions
             eventActionBuilder.Using((projection, anEvent, context) =>
             {
                 projector(projection, anEvent);
-                return Task.FromResult(false);
+                return SpecializedTasks.FalseTask;
             });
         }
 

diff --git a/Src/LiquidProjections/Projector.cs b/Src/LiquidProjections/Projector.cs
@@ -9,7 +9,7 @@ public class Projector
     {
         private readonly IEventMap<ProjectionContext> map;
         private readonly IReadOnlyList<Projector> children;
-        private ShouldRetry shouldRetry = (exception, count) => Task.FromResult(false);
+        private ShouldRetry shouldRetry = (exception, count) => SpecializedTasks.FalseTask;
 
         public Projector(IEventMapBuilder<ProjectionContext> eventMapBuilder, IEnumerable<Projector> children = null)
             : this(BuildMap(eventMapBuilder), children)

diff --git a/Src/LiquidProjections/SpecializedTasks.cs b/Src/LiquidProjections/SpecializedTasks.cs
@@ -0,0 +1,10 @@
+using System.Threading.Tasks;
+
+namespace LiquidProjections
+{
+    internal static class SpecializedTasks
+    {
+        internal static readonly Task<bool> FalseTask = Task.FromResult(false);
+        internal static readonly Task<int> ZeroTask = Task.FromResult(0);
+    }
+}