From 7c4ce4bca3ef66859f91d5b4c0dea9e5b72b5e6a Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Tue, 18 Jul 2023 14:45:33 +0600
Subject: [PATCH] Make dispatcher more usable on non-ui threads

---
 .../Threading/AvaloniaSynchronizationContext.cs            | 7 ++++---
 src/Avalonia.Base/Threading/Dispatcher.Invoke.cs           | 4 ++--
 src/Avalonia.Base/Threading/Dispatcher.MainLoop.cs         | 2 +-
 src/Avalonia.Base/Threading/DispatcherOperation.cs         | 2 +-
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs b/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs
index e0563876bf..1efaa01442 100644
--- a/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs
+++ b/src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs
@@ -99,14 +99,15 @@ namespace Avalonia.Threading
             }
         }
 
-        public static RestoreContext Ensure(DispatcherPriority priority)
+        public static RestoreContext Ensure(DispatcherPriority priority) => Ensure(Dispatcher.UIThread, priority);
+        public static RestoreContext Ensure(Dispatcher dispatcher, DispatcherPriority priority)
         {
             if (Current is AvaloniaSynchronizationContext avaloniaContext 
                 && avaloniaContext.Priority == priority)
                 return default;
             var oldContext = Current;
-            Dispatcher.UIThread.VerifyAccess();
-            SetSynchronizationContext(Dispatcher.UIThread.GetContextWithPriority(priority));
+            dispatcher.VerifyAccess();
+            SetSynchronizationContext(dispatcher.GetContextWithPriority(priority));
             return new RestoreContext(oldContext);
         }
     }
diff --git a/src/Avalonia.Base/Threading/Dispatcher.Invoke.cs b/src/Avalonia.Base/Threading/Dispatcher.Invoke.cs
index 5995a03758..add990bd57 100644
--- a/src/Avalonia.Base/Threading/Dispatcher.Invoke.cs
+++ b/src/Avalonia.Base/Threading/Dispatcher.Invoke.cs
@@ -106,7 +106,7 @@ public partial class Dispatcher
         // call the callback directly.
         if (!cancellationToken.IsCancellationRequested && priority == DispatcherPriority.Send && CheckAccess())
         {
-            using (AvaloniaSynchronizationContext.Ensure(priority))
+            using (AvaloniaSynchronizationContext.Ensure(this, priority))
                 callback();
             return;
         }
@@ -228,7 +228,7 @@ public partial class Dispatcher
         // call the callback directly.
         if (!cancellationToken.IsCancellationRequested && priority == DispatcherPriority.Send && CheckAccess())
         {
-            using (AvaloniaSynchronizationContext.Ensure(priority))
+            using (AvaloniaSynchronizationContext.Ensure(this, priority))
                 return callback();
         }
 
diff --git a/src/Avalonia.Base/Threading/Dispatcher.MainLoop.cs b/src/Avalonia.Base/Threading/Dispatcher.MainLoop.cs
index e1833fef2b..4b60ee7479 100644
--- a/src/Avalonia.Base/Threading/Dispatcher.MainLoop.cs
+++ b/src/Avalonia.Base/Threading/Dispatcher.MainLoop.cs
@@ -49,7 +49,7 @@ public partial class Dispatcher
         try
         {
             _frames.Push(frame);
-            using (AvaloniaSynchronizationContext.Ensure(DispatcherPriority.Normal))
+            using (AvaloniaSynchronizationContext.Ensure(this, DispatcherPriority.Normal))
                 frame.Run(_controlledImpl);
         }
         finally
diff --git a/src/Avalonia.Base/Threading/DispatcherOperation.cs b/src/Avalonia.Base/Threading/DispatcherOperation.cs
index 8bd6d3bc01..0008d771c6 100644
--- a/src/Avalonia.Base/Threading/DispatcherOperation.cs
+++ b/src/Avalonia.Base/Threading/DispatcherOperation.cs
@@ -258,7 +258,7 @@ public class DispatcherOperation
 
         try
         {
-            using (AvaloniaSynchronizationContext.Ensure(Priority))
+            using (AvaloniaSynchronizationContext.Ensure(Dispatcher, Priority))
                 InvokeCore();
         }
         finally