Cleanup runtime platform classes #2

src/Android/Avalonia.Android/AndroidPlatform.cs

@@ -20,6 +20,7 @@ public static class AndroidApplicationExtensions
         public static AppBuilder UseAndroid(this AppBuilder builder)
         {
             return builder
+                .UseStandardRuntimePlatformSubsystem()
                 .UseWindowingSubsystem(() => AndroidPlatform.Initialize(), "Android")
                 .UseSkia();
         }

src/Avalonia.Base/Compatibility/NativeLibrary.cs

@@ -0,0 +1,122 @@
+using System;
+using System.ComponentModel;
+using System.Reflection;
+using System.Runtime.InteropServices;
+using Avalonia.Compatibility;
+using Avalonia.Platform.Interop;
+
+namespace Avalonia.Compatibility
+{
+    internal class NativeLibraryEx
+    {
+#if NET6_0_OR_GREATER
+        public static IntPtr Load(string dll, Assembly assembly) => NativeLibrary.Load(dll, assembly, null);
+        public static IntPtr Load(string dll) => NativeLibrary.Load(dll);
+        public static bool TryGetExport(IntPtr handle, string name, out IntPtr address) =>
+            NativeLibrary.TryGetExport(handle, name, out address);
+#else
+        public static IntPtr Load(string dll, Assembly assembly) => Load(dll);
+        public static IntPtr Load(string dll)
+        {
+            var handle = DlOpen!(dll);
+            if (handle != IntPtr.Zero)
+                return handle;
+            throw new InvalidOperationException("Unable to load " + dll, DlError!());
+        }
+
+        public static bool TryGetExport(IntPtr handle, string name, out IntPtr address)
+        {
+            try
+            {
+                address = DlSym!(handle, name);
+                return address != default;
+            }
+            catch (Exception)
+            {
+                address = default;
+                return false;
+            }
+        }
+
+        static NativeLibraryEx()
+        {
+            if (OperatingSystemEx.IsWindows())
+            {
+                Win32Imports.Init();
+            }
+            else if (OperatingSystemEx.IsLinux() || OperatingSystemEx.IsMacOS())
+            {
+                var buffer = Marshal.AllocHGlobal(0x1000);
+                uname(buffer);
+                var unixName = Marshal.PtrToStringAnsi(buffer);
+                Marshal.FreeHGlobal(buffer);
+                if (unixName == "Darwin")
+                    OsXImports.Init();
+                else
+                    LinuxImports.Init();
+            }
+        }
+
+        private static Func<string, IntPtr>? DlOpen;
+        private static Func<IntPtr, string, IntPtr>? DlSym;
+        private static Func<Exception?>? DlError;
+
+        [DllImport("libc")]
+        static extern int uname(IntPtr buf);
+
+        static class Win32Imports
+        {
+            [DllImport("kernel32", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
+            private static extern IntPtr GetProcAddress(IntPtr hModule, string procName);
+
+            [DllImport("kernel32", EntryPoint = "LoadLibraryW", SetLastError = true, CharSet = CharSet.Unicode)]
+            private static extern IntPtr LoadLibrary(string lpszLib);
+
+            public static void Init()
+            {
+                DlOpen = LoadLibrary;
+                DlSym = GetProcAddress;
+                DlError = () => new Win32Exception(Marshal.GetLastWin32Error());
+            }
+        }
+
+        static class LinuxImports
+        {
+            [DllImport("libdl.so.2")]
+            private static extern IntPtr dlopen(string path, int flags);
+
+            [DllImport("libdl.so.2")]
+            private static extern IntPtr dlsym(IntPtr handle, string symbol);
+
+            [DllImport("libdl.so.2")]
+            private static extern IntPtr dlerror();
+
+            public static void Init()
+            {
+                DlOpen = s => dlopen(s, 1);
+                DlSym = dlsym;
+                DlError = () => new InvalidOperationException(Marshal.PtrToStringAnsi(dlerror()));
+            }
+        }
+
+        static class OsXImports
+        {
+            [DllImport("/usr/lib/libSystem.dylib")]
+            private static extern IntPtr dlopen(string path, int flags);
+
+            [DllImport("/usr/lib/libSystem.dylib")]
+            private static extern IntPtr dlsym(IntPtr handle, string symbol);
+
+            [DllImport("/usr/lib/libSystem.dylib")]
+            private static extern IntPtr dlerror();
+
+            public static void Init()
+            {
+                DlOpen = s => dlopen(s, 1);
+                DlSym = dlsym;
+                DlError = () => new InvalidOperationException(Marshal.PtrToStringAnsi(dlerror()));
+            }
+        }
+#endif
+    }
+}

src/Avalonia.Base/Platform/IRuntimePlatform.cs

@@ -3,24 +3,13 @@
 
 namespace Avalonia.Platform
 {
-    [Unstable]
+    [PrivateApi]
     public interface IRuntimePlatform
     {
-        IDisposable StartSystemTimer(TimeSpan interval, Action tick);
         RuntimePlatformInfo GetRuntimeInfo();
-        IUnmanagedBlob AllocBlob(int size);
     }
 
-    [Unstable]
-    public interface IUnmanagedBlob : IDisposable
-    {
-        IntPtr Address { get; }
-        int Size { get; }
-        bool IsDisposed { get; }
-
-    }
-
-    [Unstable]
+    [PrivateApi]
     public record struct RuntimePlatformInfo
     {
         public FormFactorType FormFactor => IsDesktop ? FormFactorType.Desktop :
@@ -29,7 +18,6 @@ public record struct RuntimePlatformInfo
         public bool IsMobile { get; set; }
     }
 
-    [Unstable]
     public enum FormFactorType
     {
         Unknown,

src/Avalonia.Base/Platform/Internal/UnmanagedBlob.cs

@@ -6,7 +6,7 @@
 
 namespace Avalonia.Platform.Internal;
 
-internal class UnmanagedBlob : IUnmanagedBlob
+internal class UnmanagedBlob
 {
     private IntPtr _address;
     private readonly object _lock = new object();

src/Avalonia.Base/Platform/StandardRuntimePlatform.cs

@@ -1,26 +1,20 @@
 using System;
 using System.Threading;
 using Avalonia.Compatibility;
+using Avalonia.Metadata;
 using Avalonia.Platform.Internal;
 
 namespace Avalonia.Platform
 {
+    [PrivateApi]
     public class StandardRuntimePlatform : IRuntimePlatform
     {
-        public IDisposable StartSystemTimer(TimeSpan interval, Action tick)
-        {
-            return new Timer(_ => tick(), null, interval, interval);
-        }
-
-        public IUnmanagedBlob AllocBlob(int size) => new UnmanagedBlob(size);
-
         private static readonly RuntimePlatformInfo s_info = new()
         {
             IsDesktop = OperatingSystemEx.IsWindows() || OperatingSystemEx.IsMacOS() || OperatingSystemEx.IsLinux(),
             IsMobile = OperatingSystemEx.IsAndroid() || OperatingSystemEx.IsIOS()
         };
-
-
+
         public virtual RuntimePlatformInfo GetRuntimeInfo() => s_info;
     }
 }