Nullable annotations for X11

src/Avalonia.X11/Avalonia.X11.csproj

@@ -13,6 +13,7 @@
   </ItemGroup>
   <Import Project="..\..\build\SourceGenerators.props" />
   <Import Project="..\..\build\TrimmingEnable.props" />
+  <Import Project="..\..\build\NullableEnable.props" />
 
   <ItemGroup>
     <Compile Remove="..\Shared\SourceGeneratorAttributes.cs"/>

src/Avalonia.X11/Dispatching/GLibDispatcherImpl.cs

@@ -1,4 +1,3 @@
-#nullable enable
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
@@ -312,4 +311,4 @@ public void Dispose()
     }
 
     public X11EventDispatcher EventDispatcher => _x11Events;
-}
+}

src/Avalonia.X11/Dispatching/X11PlatformThreading.cs

@@ -186,8 +186,8 @@ public void Signal()
 
         public bool CurrentThreadIsLoopThread => Thread.CurrentThread == _mainThread;
 
-        public event Action Signaled;
-        public event Action Timer;
+        public event Action? Signaled;
+        public event Action? Timer;
 
         public void UpdateTimer(long? dueTimeInMs)
         {

src/Avalonia.X11/Glx/Glx.cs

@@ -115,6 +115,9 @@ public static IntPtr SafeGetProcAddress(string proc)
         public string[] GetExtensions(IntPtr display)
         {
             var s = Marshal.PtrToStringAnsi(QueryExtensionsString(display, 0));
+            if (string.IsNullOrEmpty(s))
+                return [];
+
             return s.Split(new[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries)
                 .Select(x => x.Trim()).ToArray();
 

src/Avalonia.X11/Glx/GlxContext.cs

@@ -1,5 +1,3 @@
-#nullable enable
-
 using System;
 using System.Collections.Generic;
 using System.Threading;

src/Avalonia.X11/Glx/GlxDisplay.cs

@@ -119,13 +119,13 @@ public GlxContext CreateContext() => CreateContext(CreatePBuffer(), null, Deferr
         public GlxContext CreateContext(IGlContext share) => CreateContext(CreatePBuffer(), share,
             share.SampleCount, share.StencilSize, true);
 
-        private GlxContext CreateContext(IntPtr defaultXid, IGlContext share,
+        private GlxContext CreateContext(IntPtr defaultXid, IGlContext? share,
             int sampleCount, int stencilSize, bool ownsPBuffer)
         {
-            var sharelist = ((GlxContext)share)?.Handle ?? IntPtr.Zero;
+            var sharelist = ((GlxContext?)share)?.Handle ?? IntPtr.Zero;
             IntPtr handle = default;
 
-            GlxContext Create(GlVersion profile)
+            GlxContext? Create(GlVersion profile)
             {
                 var profileMask = GLX_CONTEXT_CORE_PROFILE_BIT_ARB;
                 if (profile.Type == GlProfileType.OpenGL && 
@@ -149,7 +149,7 @@ GlxContext Create(GlVersion profile)
                     if (handle != IntPtr.Zero)
                     {
                         _version = profile;
-                        return new GlxContext(new GlxInterface(), handle, this, (GlxContext)share, profile,
+                        return new GlxContext(new GlxInterface(), handle, this, (GlxContext?)share, profile,
                             sampleCount, stencilSize, _x11, defaultXid, ownsPBuffer);
 
                     }
@@ -162,7 +162,7 @@ GlxContext Create(GlVersion profile)
                 return null;
             }
 
-            GlxContext rv = null;
+            GlxContext? rv = null;
             if (_version.HasValue)
             {
                 rv = Create(_version.Value);

src/Avalonia.X11/Glx/GlxGlPlatformSurface.cs

@@ -96,7 +96,7 @@ public void Dispose()
 
                 public PixelSize Size => _size ?? _info.Size;
                 public double Scaling => _info.Scaling;
-                public bool IsYFlipped { get; }
+                public bool IsYFlipped => false;
             }
         }
     }

src/Avalonia.X11/Glx/GlxPlatformFeature.cs

@@ -8,23 +8,25 @@ namespace Avalonia.X11.Glx
 {
     internal class GlxPlatformGraphics : IPlatformGraphics
     {
-        public GlxDisplay Display { get; private set; }
+        public GlxDisplay Display { get; }
         public bool CanCreateContexts => true;
         public bool CanShareContexts => true;
         public bool UsesSharedContext => false;
         IPlatformGraphicsContext IPlatformGraphics.CreateContext() => Display.CreateContext();
 
         public IPlatformGraphicsContext GetSharedContext() => throw new NotSupportedException();
-
-        public static GlxPlatformGraphics TryCreate(X11Info x11, IList<GlVersion> glProfiles)
+
+        public GlxPlatformGraphics(GlxDisplay display)
+        {
+            Display = display;
+        }
+
+        public static GlxPlatformGraphics? TryCreate(X11Info x11, IList<GlVersion> glProfiles)
         {
             try
             {
                 var disp = new GlxDisplay(x11, glProfiles);
-                return new GlxPlatformGraphics
-                {
-                    Display = disp
-                };
+                return new GlxPlatformGraphics(disp);
             }
             catch(Exception e)
             {

src/Avalonia.X11/Interop/Glib.cs

@@ -1,9 +1,10 @@
 #nullable enable
+
 using System;
 using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Avalonia.Platform.Interop;
-using static Avalonia.X11.Interop.Glib;
+
 namespace Avalonia.X11.Interop;
 
 internal static unsafe class Glib
@@ -75,7 +76,7 @@ public static uint g_timeout_add_once(uint interval, Action cb) =>
     private static readonly GDestroyNotify s_gcHandleDestroyNotify = handle => GCHandle.FromIntPtr(handle).Free();
 
     private static readonly GSourceFunc s_sourceFuncDispatchCallback =
-        handle => ((Func<bool>)GCHandle.FromIntPtr(handle).Target)() ? 1 : 0;
+        handle => ((Func<bool>)GCHandle.FromIntPtr(handle).Target!)() ? 1 : 0;
 
     [DllImport(GlibName)]
     private static extern uint g_idle_add_full (int priority, GSourceFunc function, IntPtr data, GDestroyNotify notify);
@@ -108,7 +109,7 @@ public enum GIOCondition
     public delegate int GUnixFDSourceFunc(int fd, GIOCondition condition, IntPtr user_data);
 
     private static readonly GUnixFDSourceFunc s_unixFdSourceCallback = (fd, cond, handle) =>
-        ((Func<int, GIOCondition, bool>)GCHandle.FromIntPtr(handle).Target)(fd, cond) ? 1 : 0;
+        ((Func<int, GIOCondition, bool>)GCHandle.FromIntPtr(handle).Target!)(fd, cond) ? 1 : 0;
 
     [DllImport(GlibName)]
     public static extern uint g_unix_fd_add_full (int priority,
@@ -152,6 +153,7 @@ public void Dispose()
     }
 
     public static IDisposable ConnectSignal<T>(IntPtr obj, string name, T handler)
+        where T : notnull
     {
         var handle = GCHandle.Alloc(handler);
         var ptr = Marshal.GetFunctionPointerForDelegate(handler);
@@ -187,4 +189,4 @@ internal unsafe struct GSList
 {
     public readonly IntPtr Data;
     public readonly GSList* Next;
-}
+}

src/Avalonia.X11/NativeDialogs/Gtk.cs

@@ -1,10 +1,10 @@
+#nullable enable
+
 using System;
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Avalonia.Platform.Interop;
-using Avalonia.Threading;
-using Avalonia.X11.Dispatching;
 using Avalonia.X11.Interop;
 
 // ReSharper disable IdentifierTypo
@@ -142,7 +142,7 @@ public static extern void
         public static IntPtr GetForeignWindow(IntPtr xid) => gdk_x11_window_foreign_new_for_display(s_display, xid);
 
         static object s_startGtkLock = new();
-        static Task<bool> s_startGtkTask;
+        static Task<bool>? s_startGtkTask;
 
         public static Task<bool> StartGtk()
         {

src/Avalonia.X11/NativeDialogs/GtkNativeFileDialogs.cs

@@ -1,11 +1,8 @@
-#nullable enable
-
-using System;
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
-using Avalonia.Controls.Platform;
 using Avalonia.Platform;
 using Avalonia.Platform.Interop;
 using Avalonia.Platform.Storage;

src/Avalonia.X11/SMLib.cs

@@ -1,4 +1,3 @@
-#nullable enable
 using System;
 using System.Runtime.InteropServices;
 

src/Avalonia.X11/Screens/X11Screen.Providers.cs

@@ -1,10 +1,9 @@
-
-#nullable enable
 using System;
 using System.Linq;
 using System.Runtime.InteropServices;
 using Avalonia.Platform;
 using static Avalonia.X11.XLib;
+
 namespace Avalonia.X11.Screens;
 
 internal partial class X11Screens
@@ -44,7 +43,7 @@ public virtual void Refresh()
 
         private unsafe Size? GetPhysicalMonitorSizeFromEDID(IntPtr rrOutput)
         {
-            if (rrOutput == IntPtr.Zero || x11 == null)
+            if (rrOutput == IntPtr.Zero)
                 return null;
             var properties = XRRListOutputProperties(x11.Display, rrOutput, out int propertyCount);
             var hasEDID = false;
@@ -130,7 +129,7 @@ internal interface IX11RawScreenInfoProvider
     {
         nint[] ScreenKeys { get; }
         event Action? Changed;
-        X11Screen? CreateScreenFromKey(nint key);
+        X11Screen CreateScreenFromKey(nint key);
     }
 
     internal unsafe struct MonitorInfo
@@ -211,20 +210,18 @@ private unsafe MonitorInfo[] MonitorInfos
             }
         }
 
-        public X11Screen? CreateScreenFromKey(nint key)
+        public X11Screen CreateScreenFromKey(nint key)
         {
-            var info = MonitorInfos.Where(x => x.Name == key).FirstOrDefault();
-
             var infos = MonitorInfos;
             for (var i = 0; i < infos.Length; i++)
             {
                 if (infos[i].Name == key)
                 {
-                    return new X11Screen(info, _x11, _scalingProvider, i);
+                    return new X11Screen(infos[i], _x11, _scalingProvider, i);
                 }
             }
 
-            return null;
+            return new FallBackScreen(default, _x11);
         }
     }
 
@@ -248,7 +245,7 @@ public FallbackScreensImpl(AvaloniaX11Platform platform)
 
         private bool UpdateRootWindowGeometry() => XGetGeometry(_info.Display, _info.RootWindow, out _geo);
 
-        public X11Screen? CreateScreenFromKey(nint key)
+        public X11Screen CreateScreenFromKey(nint key)
         {
             return new FallBackScreen(new PixelRect(0, 0, _geo.width, _geo.height), _info);
         }

src/Avalonia.X11/Screens/X11Screens.Scaling.cs

@@ -1,4 +1,3 @@
-#nullable enable
 using System;
 using System.Collections.Generic;
 using System.Globalization;

src/Avalonia.X11/Screens/X11Screens.cs

@@ -1,12 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Globalization;
-using System.Linq;
-using System.Runtime.InteropServices;
-using System.Threading.Tasks;
 using Avalonia.Platform;
 using static Avalonia.X11.Screens.X11Screens;
-using static Avalonia.X11.XLib;
 
 namespace Avalonia.X11.Screens
 {

src/Avalonia.X11/TransparencyHelper.cs

@@ -2,8 +2,6 @@
 using System.Collections.Generic;
 using Avalonia.Controls;
 
-#nullable enable
-
 namespace Avalonia.X11
 {
     internal class TransparencyHelper :  IDisposable

src/Avalonia.X11/Vulkan/VulkanSupport.cs

@@ -1,5 +1,3 @@
-#nullable enable
-
 using System;
 using System.Collections.Generic;
 using System.Runtime.InteropServices;

src/Avalonia.X11/X11Atoms.cs

@@ -222,7 +222,7 @@ public IntPtr GetAtom(string name)
             return atom;
         }
 
-        public string GetAtomName(IntPtr atom)
+        public string? GetAtomName(IntPtr atom)
         {
             if (_atomsToNames.TryGetValue(atom, out var rv))
                 return rv;