This fixes a race condition when creating multiple VLC controls. Prev…

…iously two different controls could get different versions of the CommonDispatcher if one tried to access it while the other was in the while loop, which would eventually lead to one of the controls getting the wrong Dispatcher and thereby crash when accessing ImageSource later.
devkanro · May 28, 2018 · e28590c · e28590c
1 parent 071ed1f
commit e28590c
Showing 1 changed file with 20 additions and 17 deletions.
diff --git a/Meta.Vlc.Wpf/ThreadSeparatedImage.cs b/Meta.Vlc.Wpf/ThreadSeparatedImage.cs
@@ -15,31 +15,34 @@ namespace Meta.Vlc.Wpf
     public sealed class ThreadSeparatedImage : ThreadSeparatedControlHost
     {
         private static Dispatcher _commonDispatcher;
+        private static object _staticLock = new object();
         public static Dispatcher CommonDispatcher
         {
             get
             {
-                if (_commonDispatcher == null)
+                lock (_staticLock)
                 {
-                    Thread separateThread = new Thread(() =>
+                    if (_commonDispatcher == null)
                     {
-                        Dispatcher.Run();
-                    })
-                    {
-                        IsBackground = true
-                    };
-                    separateThread.SetApartmentState(ApartmentState.STA);
-                    separateThread.Priority = ThreadPriority.Highest;
-
-                    separateThread.Start();
-
-                    while (Dispatcher.FromThread(separateThread) == null)
-                    {
-                        Thread.Sleep(50);
+                        Thread separateThread = new Thread(() =>
+                        {
+                            Dispatcher.Run();
+                        })
+                        {
+                            IsBackground = true
+                        };
+                        separateThread.SetApartmentState(ApartmentState.STA);
+                        separateThread.Priority = ThreadPriority.Highest;
+
+                        separateThread.Start();
+
+                        while (Dispatcher.FromThread(separateThread) == null)
+                        {
+                            Thread.Sleep(50);
+                        }
+                        _commonDispatcher = Dispatcher.FromThread(separateThread);
                     }
-                    _commonDispatcher = Dispatcher.FromThread(separateThread);
                 }
-
                 return _commonDispatcher;
             }
         }