Disposing many viewers at once fixes

src/Vlc.DotNet.Core.Interops/VlcLibraryLoader.cs

@@ -38,6 +38,11 @@ internal class VlcLibraryLoader: IDisposable
         /// </summary>
         private readonly Dictionary<string, object> myInteropDelegates = new Dictionary<string, object>();
 
+        /// <summary>
+        /// A lock object for working with myInteropDelegates
+        /// </summary>
+        private readonly object _myInteropDelegatesLockObject = new object();
+
         private VlcLibraryLoader(DirectoryInfo dynamicLinkLibrariesPath)
         {
             myDynamicLinkLibrariesPath = dynamicLinkLibrariesPath;
@@ -80,18 +85,24 @@ internal T GetInteropDelegate<T>()
                     throw new Exception("Could not find the LibVlcFunctionAttribute.");
                 var attr = (LibVlcFunctionAttribute)attrs[0];
                 vlcFunctionName = attr.FunctionName;
-                if (myInteropDelegates.ContainsKey(vlcFunctionName))
+
+                lock (this._myInteropDelegatesLockObject)
                 {
-                    return (T)myInteropDelegates[attr.FunctionName];
-                }
+                    if (myInteropDelegates.ContainsKey(vlcFunctionName))
+                    {
+                        return (T)myInteropDelegates[attr.FunctionName];
+                    }
+
+                    var procAddress = Win32Interops.GetProcAddress(myLibVlcDllHandle, attr.FunctionName);
+                    if (procAddress == IntPtr.Zero)
+                        throw new Win32Exception();
 
-                var procAddress = Win32Interops.GetProcAddress(myLibVlcDllHandle, attr.FunctionName);
-                if (procAddress == IntPtr.Zero)
-                    throw new Win32Exception();
+                    var delegateForFunctionPointer = MarshalHelper.GetDelegateForFunctionPointer<T>(procAddress);
 
-                var delegateForFunctionPointer = MarshalHelper.GetDelegateForFunctionPointer<T>(procAddress);
-                myInteropDelegates[attr.FunctionName] = delegateForFunctionPointer;
-                return delegateForFunctionPointer;
+                    myInteropDelegates[attr.FunctionName] = delegateForFunctionPointer;
+
+                    return delegateForFunctionPointer;
+                }
             }
             catch (Win32Exception e)
             {

src/Vlc.DotNet.Core/VlcMediaPlayer/VlcMediaPlayer.Events.Log.cs

@@ -61,9 +61,9 @@ private void OnLogInternal(IntPtr data, VlcLogLevel level, IntPtr ctx, string fo
                 var utf8Buffer = Marshal.AllocHGlobal(byteLength);
 
                 string formattedDecodedMessage;
-                try {
+                try 
+                {
                     Win32Interops.vsprintf(utf8Buffer, format, args);
-
                     formattedDecodedMessage = Utf8InteropStringConverter.Utf8InteropToString(utf8Buffer);
                 }
                 finally
@@ -78,11 +78,16 @@ private void OnLogInternal(IntPtr data, VlcLogLevel level, IntPtr ctx, string fo
 
                 // Do the notification on another thread, so that VLC is not interrupted by the logging
 #if NETSTANDARD1_3 || NETSTANDARD2_0 || NET45
-                Task.Run(() => this.log(this.myMediaPlayerInstance, new VlcMediaPlayerLogEventArgs(level, formattedDecodedMessage, module, file, line)));
+                Task.Run(() => 
+                {
+                    if(this.log != null)
+                        this.log(this.myMediaPlayerInstance, new VlcMediaPlayerLogEventArgs(level, formattedDecodedMessage, module, file, line));
+                });
 #else
                 ThreadPool.QueueUserWorkItem(eventArgs =>
                 {
-                    this.log(this.myMediaPlayerInstance, (VlcMediaPlayerLogEventArgs)eventArgs);
+                    if (this.log != null)
+                        this.log(this.myMediaPlayerInstance, (VlcMediaPlayerLogEventArgs)eventArgs);
                 }, new VlcMediaPlayerLogEventArgs(level, formattedDecodedMessage, module, file, line));
 #endif
             }