Remove unused code from UnmanagedLibrary (#3799)

Co-authored-by: Tig <tig@users.noreply.github.com>

Author: kasperk81

Terminal.Gui/ConsoleDrivers/CursesDriver/UnmanagedLibrary.cs

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#define GUICS
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.InteropServices;
 
@@ -27,81 +26,6 @@ namespace Unix.Terminal;
 /// </summary>
 internal class UnmanagedLibrary
 {
-    private const string UnityEngineApplicationClassName = "UnityEngine.Application, UnityEngine";
-    private const string XamarinAndroidObjectClassName = "Java.Lang.Object, Mono.Android";
-    private const string XamarinIOSObjectClassName = "Foundation.NSObject, Xamarin.iOS";
-    private static readonly bool IsWindows;
-    private static readonly bool IsLinux;
-    private static readonly bool Is64Bit;
-#if GUICS
-    private static readonly bool IsMono;
-#else
-		static bool IsMono, IsUnity, IsXamarinIOS, IsXamarinAndroid, IsXamarin;
-#endif
-    private static bool IsNetCore;
-    public static bool IsMacOSPlatform { get; }
-
-    [DllImport ("libc")]
-    private static extern int uname (nint buf);
-
-    private static string GetUname ()
-    {
-        nint buffer = Marshal.AllocHGlobal (8192);
-
-        try
-        {
-            if (uname (buffer) == 0)
-            {
-                return Marshal.PtrToStringAnsi (buffer);
-            }
-
-            return string.Empty;
-        }
-        catch
-        {
-            return string.Empty;
-        }
-        finally
-        {
-            if (buffer != nint.Zero)
-            {
-                Marshal.FreeHGlobal (buffer);
-            }
-        }
-    }
-
-    [UnconditionalSuppressMessage ("AOT", "IL3050:Calling members annotated with 'RequiresDynamicCodeAttribute' may break functionality when AOT compiling.", Justification = "<Pending>")]
-    static UnmanagedLibrary ()
-    {
-        PlatformID platform = Environment.OSVersion.Platform;
-
-        IsMacOSPlatform = platform == PlatformID.Unix && GetUname () == "Darwin";
-        IsLinux = platform == PlatformID.Unix && !IsMacOSPlatform;
-
-        IsWindows = platform == PlatformID.Win32NT
-                    || platform == PlatformID.Win32S
-                    || platform == PlatformID.Win32Windows;
-        Is64Bit = Marshal.SizeOf (typeof (nint)) == 8;
-        IsMono = Type.GetType ("Mono.Runtime") != null;
-
-        if (!IsMono)
-        {
-            IsNetCore = Type.GetType ("System.MathF") != null;
-        }
-#if GUICS
-
-        //IsUnity = IsXamarinIOS = IsXamarinAndroid = IsXamarin = false;
-#else
-			IsUnity = Type.GetType (UnityEngineApplicationClassName) != null;
-			IsXamarinIOS = Type.GetType (XamarinIOSObjectClassName) != null;
-			IsXamarinAndroid = Type.GetType (XamarinAndroidObjectClassName) != null;
-			IsXamarin = IsXamarinIOS || IsXamarinAndroid;
-#endif
-    }
-
-    // flags for dlopen
-    private const int RTLD_LAZY = 1;
-    private const int RTLD_GLOBAL = 8;
     public readonly string LibraryPath;
     public nint NativeLibraryHandle { get; }
 
@@ -114,15 +38,25 @@ public UnmanagedLibrary (string [] libraryPathAlternatives, bool isFullPath)
     {
         if (isFullPath)
         {
-            LibraryPath = FirstValidLibraryPath (libraryPathAlternatives);
-            NativeLibraryHandle = PlatformSpecificLoadLibrary (LibraryPath);
+            foreach (string path in libraryPathAlternatives)
+            {
+                if (File.Exists (path))
+                {
+                    LibraryPath = path;
+                    break;
+                }
+            }
+
+            if (LibraryPath is null)
+                throw new FileNotFoundException ($"Error loading native library. Not found in any of the possible locations: {string.Join (",", libraryPathAlternatives)}");
+
+            NativeLibraryHandle = NativeLibrary.Load (LibraryPath);
         }
         else
         {
             foreach (string lib in libraryPathAlternatives)
             {
-                NativeLibraryHandle = PlatformSpecificLoadLibrary (lib);
-
+                NativeLibraryHandle = NativeLibrary.Load (lib);
                 if (NativeLibraryHandle != nint.Zero)
                 {
                     LibraryPath = lib;
@@ -143,55 +77,7 @@ public UnmanagedLibrary (string [] libraryPathAlternatives, bool isFullPath)
     /// <returns></returns>
     public nint LoadSymbol (string symbolName)
     {
-        if (IsWindows)
-        {
-            // See http://stackoverflow.com/questions/10473310 for background on this.
-            if (Is64Bit)
-            {
-                return Windows.GetProcAddress (NativeLibraryHandle, symbolName);
-            }
-
-            // Yes, we could potentially predict the size... but it's a lot simpler to just try
-            // all the candidates. Most functions have a suffix of @0, @4 or @8 so we won't be trying
-            // many options - and if it takes a little bit longer to fail if we've really got the wrong
-            // library, that's not a big problem. This is only called once per function in the native library.
-            symbolName = "_" + symbolName + "@";
-
-            for (var stackSize = 0; stackSize < 128; stackSize += 4)
-            {
-                nint candidate = Windows.GetProcAddress (NativeLibraryHandle, symbolName + stackSize);
-
-                if (candidate != nint.Zero)
-                {
-                    return candidate;
-                }
-            }
-
-            // Fail.
-            return nint.Zero;
-        }
-
-        if (IsLinux)
-        {
-            if (IsMono)
-            {
-                return Mono.dlsym (NativeLibraryHandle, symbolName);
-            }
-
-            if (IsNetCore)
-            {
-                return CoreCLR.dlsym (NativeLibraryHandle, symbolName);
-            }
-
-            return Linux.dlsym (NativeLibraryHandle, symbolName);
-        }
-
-        if (IsMacOSPlatform)
-        {
-            return MacOSX.dlsym (NativeLibraryHandle, symbolName);
-        }
-
-        throw new InvalidOperationException ("Unsupported platform.");
+        return NativeLibrary.GetExport(NativeLibraryHandle, symbolName);
     }
 
     public T GetNativeMethodDelegate<T> (string methodName)
@@ -206,128 +92,4 @@ public T GetNativeMethodDelegate<T> (string methodName)
 
         return Marshal.GetDelegateForFunctionPointer<T> (ptr); // non-generic version is obsolete
     }
-
-    /// <summary>Loads library in a platform specific way.</summary>
-    private static nint PlatformSpecificLoadLibrary (string libraryPath)
-    {
-        if (IsWindows)
-        {
-            return Windows.LoadLibrary (libraryPath);
-        }
-
-        if (IsLinux)
-        {
-            if (IsMono)
-            {
-                return Mono.dlopen (libraryPath, RTLD_GLOBAL + RTLD_LAZY);
-            }
-
-            if (IsNetCore)
-            {
-                try
-                {
-                    return CoreCLR.dlopen (libraryPath, RTLD_GLOBAL + RTLD_LAZY);
-                }
-                catch (Exception)
-                {
-                    IsNetCore = false;
-                }
-            }
-
-            return Linux.dlopen (libraryPath, RTLD_GLOBAL + RTLD_LAZY);
-        }
-
-        if (IsMacOSPlatform)
-        {
-            return MacOSX.dlopen (libraryPath, RTLD_GLOBAL + RTLD_LAZY);
-        }
-
-        throw new InvalidOperationException ("Unsupported platform.");
-    }
-
-    private static string FirstValidLibraryPath (string [] libraryPathAlternatives)
-    {
-        foreach (string path in libraryPathAlternatives)
-        {
-            if (File.Exists (path))
-            {
-                return path;
-            }
-        }
-
-        throw new FileNotFoundException (
-                                         string.Format (
-                                                        "Error loading native library. Not found in any of the possible locations: {0}",
-                                                        string.Join (",", libraryPathAlternatives)
-                                                       )
-                                        );
-    }
-
-    private static class Windows
-    {
-        [DllImport ("kernel32.dll")]
-        internal static extern nint GetProcAddress (nint hModule, string procName);
-
-        [DllImport ("kernel32.dll")]
-        internal static extern nint LoadLibrary (string filename);
-    }
-
-    private static class Linux
-    {
-        [DllImport ("libdl.so")]
-        internal static extern nint dlopen (string filename, int flags);
-
-        [DllImport ("libdl.so")]
-        internal static extern nint dlsym (nint handle, string symbol);
-    }
-
-    private static class MacOSX
-    {
-        [DllImport ("libSystem.dylib")]
-        internal static extern nint dlopen (string filename, int flags);
-
-        [DllImport ("libSystem.dylib")]
-        internal static extern nint dlsym (nint handle, string symbol);
-    }
-
-    /// <summary>
-    ///     On Linux systems, using dlopen and dlsym results in DllNotFoundException("libdl.so not found") if
-    ///     libc6-dev is not installed. As a workaround, we load symbols for dlopen and dlsym from the current process as on
-    ///     Linux Mono sure is linked against these symbols.
-    /// </summary>
-    private static class Mono
-    {
-        [DllImport ("__Internal")]
-        internal static extern nint dlopen (string filename, int flags);
-
-        [DllImport ("__Internal")]
-        internal static extern nint dlsym (nint handle, string symbol);
-    }
-
-    /// <summary>
-    ///     Similarly as for Mono on Linux, we load symbols for dlopen and dlsym from the "libcoreclr.so", to avoid the
-    ///     dependency on libc-dev Linux.
-    /// </summary>
-    private static class CoreCLR
-    {
-        // Custom resolver to support true single-file apps
-        // (those which run directly from bundle; in-memory).
-        //	 -1 on Unix means self-referencing binary (libcoreclr.so)
-        //	 0 means fallback to CoreCLR's internal resolution
-        // Note: meaning of -1 stay the same even for non-single-file form factors.
-        static CoreCLR ()
-        {
-            NativeLibrary.SetDllImportResolver (
-                                                typeof (CoreCLR).Assembly,
-                                                (libraryName, assembly, searchPath) =>
-                                                    libraryName == "libcoreclr.so" ? -1 : nint.Zero
-                                               );
-        }
-
-        [DllImport ("libcoreclr.so")]
-        internal static extern nint dlopen (string filename, int flags);
-
-        [DllImport ("libcoreclr.so")]
-        internal static extern nint dlsym (nint handle, string symbol);
-    }
 }

Terminal.Gui/ConsoleDrivers/CursesDriver/binding.cs

@@ -380,9 +380,9 @@ private static nint get_ptr (string key)
 
     private static void LoadMethods ()
     {
-        string [] libs = UnmanagedLibrary.IsMacOSPlatform
-                             ? new [] { "libncurses.dylib" }
-                             : new [] { "libncursesw.so.6", "libncursesw.so.5" };
+        string [] libs = OperatingSystem.IsMacOS()
+                             ? ["libncurses.dylib"]
+                             : ["libncursesw.so.6", "libncursesw.so.5"];
         var attempts = 1;
 
         while (true)