feat(nulls): prevents the flash of null data between component iterations

overrides the ExpireDownStreamObjects() (c) @alanrynne 🙌

fixes #2 and fixes #3 too i think

GrasshopperAsyncComponent/Base/GH_AsyncComponent.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Grasshopper.Kernel;
@@ -19,12 +20,14 @@ namespace GrasshopperAsyncComponent
 
     public override GH_Exposure Exposure => GH_Exposure.hidden;
 
-    Action<string> ReportProgress;
-
     Action<string, GH_RuntimeMessageLevel> ReportError;
 
     List<(string, GH_RuntimeMessageLevel)> Errors;
 
+    Action<string, double> ReportProgress;
+
+    ConcurrentDictionary<string, double> ProgressReports;
+    
     Action Done;
 
     Timer DisplayProgressTimer;
@@ -55,15 +58,31 @@ namespace GrasshopperAsyncComponent
       DisplayProgressTimer = new Timer(333) { AutoReset = false };
       DisplayProgressTimer.Elapsed += (s, e) =>
       {
+        if (Workers.Count == 0) return;
+        if (Workers.Count == 1)
+        {
+          Message = ProgressReports.Values.Last().ToString("0.00%");
+        }
+        else
+        {
+          double total = 0;
+          foreach (var kvp in ProgressReports)
+          {
+            total += kvp.Value;
+          }
+
+          Message = (total / Workers.Count).ToString("0.00%");
+        }
+
         Rhino.RhinoApp.InvokeOnUiThread((Action)delegate
         {
           OnDisplayExpired(true);
         });
       };
 
-      ReportProgress = (progress) =>
+      ReportProgress = (id, value) =>
       {
-        Message = progress;
+        ProgressReports[id] = value;
         if (!DisplayProgressTimer.Enabled) DisplayProgressTimer.Start();
       };
 
@@ -87,6 +106,7 @@ namespace GrasshopperAsyncComponent
       };
 
       Errors = new List<(string, GH_RuntimeMessageLevel)>();
+      ProgressReports = new ConcurrentDictionary<string, double>();
 
       Workers = new List<WorkerInstance>();
       CancelationSources = new List<CancellationTokenSource>();
@@ -102,9 +122,12 @@ namespace GrasshopperAsyncComponent
       CancelationSources.Clear();
       Workers.Clear();
       Errors.Clear();
+      ProgressReports.Clear();
       Tasks.Clear();
 
       State = 0;
+
+      var test = Params.Output[0].VolatileData;
     }
 
     protected override void AfterSolveInstance()
@@ -113,9 +136,17 @@ namespace GrasshopperAsyncComponent
       if (State == 0 && Tasks.Count > 0)
       {
         foreach (var task in Tasks) task.Start();
+        var test = Params.Output[0].VolatileData;
       }
     }
 
+    protected override void ExpireDownStreamObjects()
+    {
+      // Prevents the flash of null data until the new solution is ready
+      if (SetData)
+        base.ExpireDownStreamObjects();
+    }
+
     protected override void SolveInstance(IGH_DataAccess DA)
     {
       if (State == 0)
@@ -139,7 +170,7 @@ namespace GrasshopperAsyncComponent
         // Create the task
         var tokenSource = new CancellationTokenSource();
         CurrentWorker.CancellationToken = tokenSource.Token;
-        CurrentWorker.Id = DA.Iteration.ToString();
+        CurrentWorker.Id = $"Worker-{DA.Iteration}";
 
         Task CurrentRun;
         if (TaskCreationOptions != null)
@@ -176,6 +207,7 @@ namespace GrasshopperAsyncComponent
           CancelationSources.Clear();
           Workers.Clear();
           Errors.Clear();
+          ProgressReports.Clear();
           Tasks.Clear();
 
           SetData = false;

GrasshopperAsyncComponent/Base/WorkerInstance.cs

@@ -37,7 +37,7 @@ namespace GrasshopperAsyncComponent
     /// <param name="ReportProgress">Call this to report progress up to the parent component.</param>
     /// <param name="ReportError">Call this to report errors up to the parent component.</param>
     /// <param name="Done">Call this when everything is <b>done</b>. It will tell the parent component that you're ready to <see cref="SetData(IGH_DataAccess)"/>.</param>
-    public abstract void DoWork(Action<string> ReportProgress, Action<string, GH_RuntimeMessageLevel> ReportError, Action Done);
+    public abstract void DoWork(Action<string, double> ReportProgress, Action<string, GH_RuntimeMessageLevel> ReportError, Action Done);
 
     /// <summary>
     /// Write your data setting logic here. <b>Do not call this function directly from this class. It will be invoked by the parent <see cref="GH_AsyncComponent"/> after you've called `Done` in the <see cref="DoWork(Action{string}, Action{string, GH_RuntimeMessageLevel}, Action)"/> function.</b>

GrasshopperAsyncComponent/GrasshopperAsyncComponent.csproj

@@ -61,7 +61,7 @@
   <ItemGroup>
     <Compile Include="Base\GH_AsyncComponent.cs" />
     <Compile Include="Info\GrasshopperAsyncComponentInfo.cs" />
-    <Compile Include="Base\IAsyncComponentWorker.cs" />
+    <Compile Include="Base\WorkerInstance.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="SampleImplementations\Sample_PrimeCalculatorAsyncComponent.cs" />
     <Compile Include="SampleImplementations\Sample_UslessCyclesComponent.cs" />

GrasshopperAsyncComponent/SampleImplementations/Sample_PrimeCalculatorAsyncComponent.cs

@@ -16,7 +16,7 @@ namespace GrasshopperAsyncComponent.SampleImplementations
 
     public override GH_Exposure Exposure => GH_Exposure.primary;
 
-    public Sample_PrimeCalculatorAsyncComponent() : base("Sample Async Component", "PRIME", "Calculates the nth prime number.", "Samples", "Async")
+    public Sample_PrimeCalculatorAsyncComponent() : base("The N-th Prime Calculator", "PRIME", "Calculates the nth prime number.", "Samples", "Async")
     {
       BaseWorker = new PrimeCalculatorWorker();
     }
@@ -28,7 +28,8 @@ namespace GrasshopperAsyncComponent.SampleImplementations
 
     protected override void RegisterOutputParams(GH_OutputParamManager pManager)
     {
-      pManager.AddTextParameter("Output", "O", "The n-th prime number.", GH_ParamAccess.item);
+      pManager.AddNumberParameter("Output", "O", "The n-th prime number.", GH_ParamAccess.item);
+
     }
   }
 
@@ -37,7 +38,7 @@ namespace GrasshopperAsyncComponent.SampleImplementations
     int TheNthPrime { get; set; } = 100;
     long ThePrime { get; set; } = -1;
 
-    public override void DoWork(Action<string> ReportProgress, Action<string, GH_RuntimeMessageLevel> ReportError, Action Done)
+    public override void DoWork(Action<string, double> ReportProgress, Action<string, GH_RuntimeMessageLevel> ReportError, Action Done)
     {
       // 👉 Checking for cancellation!
       if (CancellationToken.IsCancellationRequested) return;
@@ -66,7 +67,7 @@ namespace GrasshopperAsyncComponent.SampleImplementations
           b++;
         }
 
-        ReportProgress(((double)(count) / TheNthPrime).ToString("0.00%"));
+        ReportProgress(Id, ((double)count) / TheNthPrime);
 
         if (prime > 0)
         {
@@ -96,7 +97,7 @@ namespace GrasshopperAsyncComponent.SampleImplementations
       // 👉 Checking for cancellation!
       if (CancellationToken.IsCancellationRequested) return;
 
-      DA.SetData(0, $"Worker {Id}: {TheNthPrime}th prime is: {ThePrime}");
+      DA.SetData(0, ThePrime);
     }
   }
 

GrasshopperAsyncComponent/SampleImplementations/Sample_UslessCyclesComponent.cs

@@ -36,7 +36,7 @@ namespace GrasshopperAsyncComponent.SampleImplementations
   {
     int MaxIterations { get; set; } = 100;
 
-    public override void DoWork(Action<string> ReportProgress, Action<string, GH_RuntimeMessageLevel> ReportError, Action Done)
+    public override void DoWork(Action<string, double> ReportProgress, Action<string, GH_RuntimeMessageLevel> ReportError, Action Done)
     {
       // Checking for cancellation
       if (CancellationToken.IsCancellationRequested) return;
@@ -47,8 +47,8 @@ namespace GrasshopperAsyncComponent.SampleImplementations
         for (int j = 0; j <= 100; j++)
           sw.SpinOnce();
 
-        ReportProgress(((double)(i + 1) / (double)MaxIterations).ToString("0.00%"));
-        
+        ReportProgress(Id, ((double)(i + 1) / (double)MaxIterations));
+
         // Checking for cancellation
         if (CancellationToken.IsCancellationRequested) return;
       }