- tweak: refactor funny

Nebula.Shared/Services/AssemblyService.cs

@@ -0,0 +1,110 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
+using System.Runtime.InteropServices;
+using System.Runtime.Loader;
+using Nebula.Shared.FileApis;
+using Robust.LoaderApi;
+
+namespace Nebula.Shared.Services;
+
+[ServiceRegister]
+public class AssemblyService
+{
+    private readonly Dictionary<string,Assembly> _assemblies = new();
+    private readonly DebugService _debugService;
+
+    public AssemblyService(DebugService debugService)
+    {
+        _debugService = debugService;
+    }
+
+    //public IReadOnlyList<Assembly> Assemblies => _assemblies;
+
+    public AssemblyApi Mount(IFileApi fileApi, string apiName = "")
+    {
+        var asmApi = new AssemblyApi(fileApi);
+        AssemblyLoadContext.Default.Resolving += (context, name) => OnAssemblyResolving(context, name, asmApi, apiName);
+        AssemblyLoadContext.Default.ResolvingUnmanagedDll += LoadContextOnResolvingUnmanaged;
+
+        return asmApi;
+    }
+
+    public bool TryGetLoader(Assembly clientAssembly, [NotNullWhen(true)] out ILoaderEntryPoint? loader)
+    {
+        loader = null;
+        // Find ILoaderEntryPoint with the LoaderEntryPointAttribute
+        var attrib = clientAssembly.GetCustomAttribute<LoaderEntryPointAttribute>();
+        if (attrib == null)
+        {
+            Console.WriteLine("No LoaderEntryPointAttribute found on Robust.Client assembly!");
+            return false;
+        }
+
+        var type = attrib.LoaderEntryPointType;
+        if (!type.IsAssignableTo(typeof(ILoaderEntryPoint)))
+        {
+            Console.WriteLine("Loader type '{0}' does not implement ILoaderEntryPoint!", type);
+            return false;
+        }
+
+        loader = (ILoaderEntryPoint)Activator.CreateInstance(type)!;
+        return true;
+    }
+
+    public bool TryOpenAssembly(string name, AssemblyApi assemblyApi, [NotNullWhen(true)] out Assembly? assembly)
+    {
+        if (_assemblies.TryGetValue(name, out assembly))
+        {
+            return true;
+        }
+        
+        if (!TryOpenAssemblyStream(name, assemblyApi, out var asm, out var pdb))
+        {
+            assembly = null;
+            return false;
+        }
+
+        assembly = AssemblyLoadContext.Default.LoadFromStream(asm, pdb);
+        _debugService.Log("LOADED ASSEMBLY " + name);
+        
+        _assemblies.Add(name, assembly);
+
+        asm.Dispose();
+        pdb?.Dispose();
+        return true;
+    }
+
+    public bool TryOpenAssemblyStream(string name, AssemblyApi assemblyApi, [NotNullWhen(true)] out Stream? asm,
+        out Stream? pdb)
+    {
+        asm = null;
+        pdb = null;
+
+        if (!assemblyApi.TryOpen($"{name}.dll", out asm))
+            return false;
+
+        assemblyApi.TryOpen($"{name}.pdb", out pdb);
+        return true;
+    }
+
+    private Assembly? OnAssemblyResolving(AssemblyLoadContext context, AssemblyName name, AssemblyApi assemblyApi,
+        string apiName)
+    {
+
+        _debugService.Debug($"Resolving assembly from {apiName}: {name.Name}");
+        return TryOpenAssembly(name.Name!, assemblyApi, out var assembly) ? assembly : null;
+    }
+
+    private IntPtr LoadContextOnResolvingUnmanaged(Assembly assembly, string unmanaged)
+    {
+        var ourDir = Path.GetDirectoryName(typeof(AssemblyApi).Assembly.Location);
+        var a = Path.Combine(ourDir!, unmanaged);
+
+        _debugService.Debug($"Loading dll lib: {a}");
+
+        if (NativeLibrary.TryLoad(a, out var handle))
+            return handle;
+
+        return IntPtr.Zero;
+    }
+}