Nullable annotation for System.Windows.Extensions

src/libraries/Common/src/Interop/Windows/Crypt32/Interop.CertOpenStore.cs

@@ -14,6 +14,6 @@ internal static partial class Crypt32
         internal const uint CERT_STORE_PROV_MEMORY = 2;
 
         [DllImport(Interop.Libraries.Crypt32, CharSet = CharSet.Unicode, SetLastError = true)]
-        internal static extern SafeCertStoreHandle CertOpenStore(IntPtr lpszStoreProvider, uint dwMsgAndCertEncodingType, IntPtr hCryptProv, uint dwFlags, string pvPara);
+        internal static extern SafeCertStoreHandle CertOpenStore(IntPtr lpszStoreProvider, uint dwMsgAndCertEncodingType, IntPtr hCryptProv, uint dwFlags, string? pvPara);
     }
 }

src/libraries/Common/src/Interop/Windows/CryptUI/Interop.CryptUIDlgCertificate.cs

@@ -15,7 +15,7 @@ internal sealed class CRYPTUI_VIEWCERTIFICATE_STRUCTW
             internal uint dwSize;
             internal IntPtr hwndParent;
             internal uint dwFlags;
-            internal string szTitle;
+            internal string? szTitle;
             internal IntPtr pCertContext;
             internal IntPtr rgszPurposes;
             internal uint cPurposes;
@@ -38,9 +38,9 @@ internal sealed class CRYPTUI_SELECTCERTIFICATE_STRUCTW
             internal uint dwSize;
             internal IntPtr hwndParent;
             internal uint dwFlags;
-            internal string szTitle;
+            internal string? szTitle;
             internal uint dwDontUseColumn;
-            internal string szDisplayString;
+            internal string? szDisplayString;
             internal IntPtr pFilterCallback;
             internal IntPtr pDisplayCallback;
             internal IntPtr pvCallbackData;

src/libraries/Common/src/Interop/Windows/WinMm/Interop.PlaySound.cs

@@ -21,6 +21,6 @@ internal static partial class WinMM
         internal static extern bool PlaySound(string soundName, IntPtr hmod, int soundFlags);
 
         [DllImport(Libraries.WinMM, ExactSpelling = true, EntryPoint = "PlaySoundW")]
-        internal static extern bool PlaySound(byte[] soundName, IntPtr hmod, int soundFlags);
+        internal static extern bool PlaySound(byte[]? soundName, IntPtr hmod, int soundFlags);
     }
 }

src/libraries/Common/src/Interop/Windows/WinMm/Interop.mmioDescend.cs

@@ -13,7 +13,7 @@ internal static partial class WinMM
         [DllImport(Libraries.WinMM)]
         internal static extern int mmioDescend(IntPtr hMIO,
                                                [MarshalAs(UnmanagedType.LPStruct)] MMCKINFO lpck,
-                                               [MarshalAs(UnmanagedType.LPStruct)] MMCKINFO lcpkParent,
+                                               [MarshalAs(UnmanagedType.LPStruct)] MMCKINFO? lcpkParent,
                                                int flags);
     }
 }

src/libraries/System.Windows.Extensions/ref/System.Windows.Extensions.cs

@@ -12,15 +12,16 @@ public partial class SoundPlayer : System.ComponentModel.Component, System.Runti
         public SoundPlayer() { }
         public SoundPlayer(System.IO.Stream stream) { }
         protected SoundPlayer(System.Runtime.Serialization.SerializationInfo serializationInfo, System.Runtime.Serialization.StreamingContext context) { }
-        public SoundPlayer(string soundLocation) { }
+        public SoundPlayer(string? soundLocation) { }
         public bool IsLoadCompleted { get { throw null; } }
         public int LoadTimeout { get { throw null; } set { } }
+        [System.Diagnostics.CodeAnalysis.AllowNullAttribute]
         public string SoundLocation { get { throw null; } set { } }
-        public System.IO.Stream Stream { get { throw null; } set { } }
-        public object Tag { get { throw null; } set { } }
-        public event System.ComponentModel.AsyncCompletedEventHandler LoadCompleted { add { } remove { } }
-        public event System.EventHandler SoundLocationChanged { add { } remove { } }
-        public event System.EventHandler StreamChanged { add { } remove { } }
+        public System.IO.Stream? Stream { get { throw null; } set { } }
+        public object? Tag { get { throw null; } set { } }
+        public event System.ComponentModel.AsyncCompletedEventHandler? LoadCompleted { add { } remove { } }
+        public event System.EventHandler? SoundLocationChanged { add { } remove { } }
+        public event System.EventHandler? StreamChanged { add { } remove { } }
         public void Load() { }
         public void LoadAsync() { }
         protected virtual void OnLoadCompleted(System.ComponentModel.AsyncCompletedEventArgs e) { }
@@ -68,7 +69,7 @@ public partial class XamlAccessLevel
     {
         internal XamlAccessLevel() { }
         public System.Reflection.AssemblyName AssemblyAccessToAssemblyName { get { throw null; } }
-        public string PrivateAccessToTypeName { get { throw null; } }
+        public string? PrivateAccessToTypeName { get { throw null; } }
         public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.Assembly assembly) { throw null; }
         public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.AssemblyName assemblyName) { throw null; }
         public static System.Xaml.Permissions.XamlAccessLevel PrivateAccessTo(string assemblyQualifiedTypeName) { throw null; }

src/libraries/System.Windows.Extensions/ref/System.Windows.Extensions.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);netcoreapp3.1</TargetFrameworks>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="System.Windows.Extensions.cs" />

src/libraries/System.Windows.Extensions/src/System.Windows.Extensions.csproj

@@ -2,6 +2,7 @@
   <PropertyGroup>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent);netcoreapp3.1-windows;netcoreapp3.1</TargetFrameworks>
+    <Nullable>enable</Nullable>
     <IsPackable>true</IsPackable>
     <PackageDescription>Provides miscellaneous Windows-specific types
 

src/libraries/System.Windows.Extensions/src/System/Media/SoundPlayer.cs

@@ -3,6 +3,7 @@
 
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net;
 using System.Runtime.InteropServices;
@@ -18,7 +19,7 @@ public class SoundPlayer : Component, ISerializable
         private const int BlockSize = 1024;
         private const int DefaultLoadTimeout = 10000; // 10 secs
 
-        private Uri _uri;
+        private Uri? _uri;
         private string _soundLocation = string.Empty;
         private int _loadTimeout = DefaultLoadTimeout;
 
@@ -28,16 +29,16 @@ public class SoundPlayer : Component, ISerializable
         // the worker copyTask
         // we start the worker copyTask ONLY from entry points in the SoundPlayer API
         // we also set the tread to null only from the entry points in the SoundPlayer API
-        private Task _copyTask;
-        private CancellationTokenSource _copyTaskCancellation;
+        private Task? _copyTask;
+        private CancellationTokenSource? _copyTaskCancellation;
 
         // local buffer information
         private int _currentPos;
-        private Stream _stream;
-        private Exception _lastLoadException;
+        private Stream? _stream;
+        private Exception? _lastLoadException;
         private bool _doesLoadAppearSynchronous;
-        private byte[] _streamData;
-        private AsyncOperation _asyncOperation;
+        private byte[]? _streamData;
+        private AsyncOperation? _asyncOperation;
         private readonly SendOrPostCallback _loadAsyncOperationCompleted;
 
         // event
@@ -50,7 +51,7 @@ public SoundPlayer()
             _loadAsyncOperationCompleted = new SendOrPostCallback(LoadAsyncOperationCompleted);
         }
 
-        public SoundPlayer(string soundLocation) : this()
+        public SoundPlayer(string? soundLocation) : this()
         {
             SetupSoundLocation(soundLocation ?? string.Empty);
         }
@@ -79,6 +80,7 @@ public int LoadTimeout
             }
         }
 
+        [AllowNull]
         public string SoundLocation
         {
             get => _soundLocation;
@@ -99,7 +101,7 @@ public string SoundLocation
             }
         }
 
-        public Stream Stream
+        public Stream? Stream
         {
             get
             {
@@ -126,7 +128,7 @@ public Stream Stream
 
         public bool IsLoadCompleted { get; private set; }
 
-        public object Tag { get; set; }
+        public object? Tag { get; set; }
 
         public void LoadAsync()
         {
@@ -161,9 +163,9 @@ public void LoadAsync()
             LoadStream(false);
         }
 
-        private void LoadAsyncOperationCompleted(object arg)
+        private void LoadAsyncOperationCompleted(object? arg)
         {
-            OnLoadCompleted((AsyncCompletedEventArgs)arg);
+            OnLoadCompleted((AsyncCompletedEventArgs)arg!);
         }
 
         // called for loading a stream synchronously
@@ -227,6 +229,7 @@ private void LoadAndPlay(int flags)
             else
             {
                 LoadSync();
+                Debug.Assert(_streamData != null);
                 ValidateSoundData(_streamData);
                 Interop.WinMM.PlaySound(_streamData, IntPtr.Zero, Interop.WinMM.SND_MEMORY | Interop.WinMM.SND_NODEFAULT | flags);
             }
@@ -271,7 +274,9 @@ private void LoadSync()
                 _stream = webResponse.GetResponseStream();
             }
 
-            if (_stream.CanSeek)
+            // DO NOT assert - NRE is expected for null stream
+            // See SoundPlayerTests.Load_NullStream_ThrowsNullReferenceException
+            if (_stream!.CanSeek)
             {
                 // if we can get data synchronously, then get it
                 LoadStream(true);
@@ -304,6 +309,7 @@ private void LoadSync()
 
         private void LoadStream(bool loadSync)
         {
+            Debug.Assert(_stream != null);
             if (loadSync && _stream.CanSeek)
             {
                 int streamLen = (int)_stream.Length;
@@ -339,9 +345,9 @@ public void PlayLooping()
             LoadAndPlay(Interop.WinMM.SND_LOOP | Interop.WinMM.SND_ASYNC);
         }
 
-        private static Uri ResolveUri(string partialUri)
+        private static Uri? ResolveUri(string partialUri)
         {
-            Uri result = null;
+            Uri? result = null;
             try
             {
                 result = new Uri(partialUri);
@@ -399,7 +405,7 @@ private void SetupSoundLocation(string soundLocation)
             }
         }
 
-        private void SetupStream(Stream stream)
+        private void SetupStream(Stream? stream)
         {
             if (_copyTask != null)
             {
@@ -420,10 +426,10 @@ private void SetupStream(Stream stream)
 
         public void Stop()
         {
-            Interop.WinMM.PlaySound((byte[])null, IntPtr.Zero, Interop.WinMM.SND_PURGE);
+            Interop.WinMM.PlaySound((byte[]?)null, IntPtr.Zero, Interop.WinMM.SND_PURGE);
         }
 
-        public event AsyncCompletedEventHandler LoadCompleted
+        public event AsyncCompletedEventHandler? LoadCompleted
         {
             add
             {
@@ -435,7 +441,7 @@ public event AsyncCompletedEventHandler LoadCompleted
             }
         }
 
-        public event EventHandler SoundLocationChanged
+        public event EventHandler? SoundLocationChanged
         {
             add
             {
@@ -447,7 +453,7 @@ public event EventHandler SoundLocationChanged
             }
         }
 
-        public event EventHandler StreamChanged
+        public event EventHandler? StreamChanged
         {
             add
             {
@@ -461,17 +467,17 @@ public event EventHandler StreamChanged
 
         protected virtual void OnLoadCompleted(AsyncCompletedEventArgs e)
         {
-            ((AsyncCompletedEventHandler)Events[s_eventLoadCompleted])?.Invoke(this, e);
+            ((AsyncCompletedEventHandler?)Events[s_eventLoadCompleted])?.Invoke(this, e);
         }
 
         protected virtual void OnSoundLocationChanged(EventArgs e)
         {
-            ((EventHandler)Events[s_eventSoundLocationChanged])?.Invoke(this, e);
+            ((EventHandler?)Events[s_eventSoundLocationChanged])?.Invoke(this, e);
         }
 
         protected virtual void OnStreamChanged(EventArgs e)
         {
-            ((EventHandler)Events[s_eventStreamChanged])?.Invoke(this, e);
+            ((EventHandler?)Events[s_eventStreamChanged])?.Invoke(this, e);
         }
 
         private async Task CopyStreamAsync(CancellationToken cancellationToken)
@@ -484,7 +490,7 @@ private async Task CopyStreamAsync(CancellationToken cancellationToken)
 #pragma warning disable SYSLIB0014 // WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.
                     WebRequest webRequest = WebRequest.Create(_uri);
 #pragma warning restore SYSLIB0014
-                    using (cancellationToken.Register(r => ((WebRequest)r).Abort(), webRequest))
+                    using (cancellationToken.Register(r => ((WebRequest)r!).Abort(), webRequest))
                     {
                         WebResponse webResponse = await webRequest.GetResponseAsync().ConfigureAwait(false);
                         _stream = webResponse.GetResponseStream();
@@ -493,6 +499,7 @@ private async Task CopyStreamAsync(CancellationToken cancellationToken)
 
                 _streamData = new byte[BlockSize];
 
+                Debug.Assert(_stream != null);
                 int readBytes = await _stream.ReadAsync(_streamData.AsMemory(_currentPos, BlockSize), cancellationToken).ConfigureAwait(false);
                 int totalBytes = readBytes;
 
@@ -525,6 +532,7 @@ private async Task CopyStreamAsync(CancellationToken cancellationToken)
                 AsyncCompletedEventArgs ea = _lastLoadException is OperationCanceledException ?
                     new AsyncCompletedEventArgs(null, cancelled: true, null) :
                     new AsyncCompletedEventArgs(_lastLoadException, cancelled: false, null);
+                Debug.Assert(_asyncOperation != null);
                 _asyncOperation.PostOperationCompleted(_loadAsyncOperationCompleted, ea);
             }
         }
@@ -539,7 +547,7 @@ private unsafe void ValidateSoundFile(string fileName)
 
             try
             {
-                Interop.WinMM.WAVEFORMATEX waveFormat = null;
+                Interop.WinMM.WAVEFORMATEX? waveFormat = null;
                 var ckRIFF = new Interop.WinMM.MMCKINFO()
                 {
                     fccType = mmioFOURCC('W', 'A', 'V', 'E')

src/libraries/System.Windows.Extensions/src/System/Media/SystemSounds.cs

@@ -5,11 +5,11 @@ namespace System.Media
 {
     public static class SystemSounds
     {
-        private static volatile SystemSound s_asterisk;
-        private static volatile SystemSound s_beep;
-        private static volatile SystemSound s_exclamation;
-        private static volatile SystemSound s_hand;
-        private static volatile SystemSound s_question;
+        private static volatile SystemSound? s_asterisk;
+        private static volatile SystemSound? s_beep;
+        private static volatile SystemSound? s_exclamation;
+        private static volatile SystemSound? s_hand;
+        private static volatile SystemSound? s_question;
 
         public static SystemSound Asterisk
         {

src/libraries/System.Windows.Extensions/src/System/Xaml/Permissions/XamlAccessLevel.cs

@@ -8,15 +8,15 @@ namespace System.Xaml.Permissions
 {
     public class XamlAccessLevel
     {
-        private XamlAccessLevel(string assemblyName, string typeName)
+        private XamlAccessLevel(string assemblyName, string? typeName)
         {
             AssemblyNameString = assemblyName;
             PrivateAccessToTypeName = typeName;
         }
 
         public static XamlAccessLevel AssemblyAccessTo(Assembly assembly)
         {
-            return new XamlAccessLevel(assembly.FullName, null);
+            return new XamlAccessLevel(assembly.FullName!, null);
         }
 
         public static XamlAccessLevel AssemblyAccessTo(AssemblyName assemblyName)
@@ -26,7 +26,7 @@ public static XamlAccessLevel AssemblyAccessTo(AssemblyName assemblyName)
 
         public static XamlAccessLevel PrivateAccessTo(Type type)
         {
-            return new XamlAccessLevel(type.Assembly.FullName, type.FullName);
+            return new XamlAccessLevel(type.Assembly.FullName!, type.FullName);
         }
 
         public static XamlAccessLevel PrivateAccessTo(string assemblyQualifiedTypeName)
@@ -43,7 +43,7 @@ public AssemblyName AssemblyAccessToAssemblyName
             get { return new AssemblyName(AssemblyNameString); }
         }
 
-        public string PrivateAccessToTypeName { get; private set; }
+        public string? PrivateAccessToTypeName { get; private set; }
 
         internal string AssemblyNameString { get; private set; }
     }