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Merge pull request #628 from CesiumGS/delegate-drama
Fix two Reinterop problems with delegates
2 parents d6b5a18 + 47d9ca7 commit 735ac52

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‎CHANGES.md‎

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@@ -1,5 +1,12 @@
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# Change Log
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## ? - ?
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##### Fixes :wrench:
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- Exceptions thrown by delegates implemented in native code are now correctly propagated back to the managed caller. Previously, this scenario could cause crashes and undefined behavior.
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- Delegate wrappers for native functions now use `SafeHandle` to ensure the native function will not be destroyed by the garbage collector while it is running.
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## v1.19.0 - 2025-11-03
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##### Additions :tada:

‎Reinterop~/CustomDelegateGenerator.cs‎

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@@ -72,7 +72,7 @@ private void GenerateDelegate(CppGenerationContext context, GeneratedResult resu
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"""
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));
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// A a C# delegate type that wraps a std::function, and arrange for
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// A C# delegate type that wraps a std::function, and arranges for
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// the invoke and dispose to be implemented in C++.
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CSharpType csType = CSharpType.FromSymbol(context, item.Type);
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@@ -88,7 +88,7 @@ private void GenerateDelegate(CppGenerationContext context, GeneratedResult resu
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string disposeCallbackName = $"{csType.GetFullyQualifiedNamespace().Replace(".", "_")}_{item.Type.Name}{genericTypeHash}_DisposeCallback";
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var invokeParameters = callbackParameters.Select(p => $"{p.CsType.GetFullyQualifiedName()} {p.Name}");
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var invokeInteropParameters = new[] { "IntPtr callbackFunction" }.Concat(callbackParameters.Select(p => $"{p.CsType.AsInteropTypeParameter().GetFullyQualifiedName()} {p.Name}"));
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var invokeInteropParameters = new[] { "ImplementationHandle callbackFunction" }.Concat(callbackParameters.Select(p => $"{p.CsType.AsInteropTypeParameter().GetFullyQualifiedName()} {p.Name}"));
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var callInvokeInteropParameters = new[] { "_callbackFunction" }.Concat(callbackParameters.Select(p => p.CsType.GetConversionToInteropType(p.Name)));
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var csReturnType = CSharpType.FromSymbol(context, invokeMethod.ReturnType);
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@@ -109,46 +109,57 @@ private void GenerateDelegate(CppGenerationContext context, GeneratedResult resu
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$$"""
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private class {{csType.Name}}{{genericTypeHash}}NativeFunction : System.IDisposable
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{
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private IntPtr _callbackFunction;
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public {{csType.Name}}{{genericTypeHash}}NativeFunction(IntPtr callbackFunction)
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internal class ImplementationHandle : Microsoft.Win32.SafeHandles.SafeHandleZeroOrMinusOneIsInvalid
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{
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_callbackFunction = callbackFunction;
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}
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public ImplementationHandle(IntPtr nativeImplementation) : base(true)
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{
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SetHandle(nativeImplementation);
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}
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~{{csType.Name}}{{genericTypeHash}}NativeFunction()
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{
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Dispose(false);
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[System.Runtime.ConstrainedExecution.ReliabilityContract(System.Runtime.ConstrainedExecution.Consistency.WillNotCorruptState, System.Runtime.ConstrainedExecution.Cer.Success)]
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protected override bool ReleaseHandle()
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{
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{{disposeCallbackName}}(this.handle);
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return true;
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}
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}
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public void Dispose()
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[System.NonSerialized]
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private ImplementationHandle _callbackFunction;
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public {{csType.Name}}{{genericTypeHash}}NativeFunction(IntPtr callbackFunction)
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{
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Dispose(true);
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GC.SuppressFinalize(this);
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_callbackFunction = new ImplementationHandle(callbackFunction);
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}
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private void Dispose(bool disposing)
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public void Dispose()
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{
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if (_callbackFunction != IntPtr.Zero)
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{
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{{disposeCallbackName}}(_callbackFunction);
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_callbackFunction = IntPtr.Zero;
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}
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if (this._callbackFunction != null && !this._callbackFunction.IsInvalid)
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this._callbackFunction.Dispose();
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this._callbackFunction = null;
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}
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public {{csReturnType.GetFullyQualifiedName()}} Invoke({{string.Join(", ", invokeParameters)}})
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public unsafe {{csReturnType.GetFullyQualifiedName()}} Invoke({{string.Join(", ", invokeParameters)}})
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{
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if (_callbackFunction == null)
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throw new System.ObjectDisposedException("{{csType.Name}}");
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{{csResultImplementation}}{{invokeCallbackName}}({{string.Join(", ", callInvokeInteropParameters)}});
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{{csReturnImplementation}};
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unsafe
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{
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System.IntPtr reinteropException = System.IntPtr.Zero;
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{{csResultImplementation}}{{invokeCallbackName}}({{string.Join(", ", callInvokeInteropParameters)}}, &reinteropException);
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if (reinteropException != System.IntPtr.Zero)
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{
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throw (System.Exception)Reinterop.ObjectHandleUtility.GetObjectAndFreeHandle(reinteropException);
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}
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{{csReturnImplementation}};
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}
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}
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[System.Runtime.InteropServices.DllImport("{{context.NativeLibraryName}}", CallingConvention=System.Runtime.InteropServices.CallingConvention.Cdecl)]
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private static extern void {{disposeCallbackName}}(IntPtr callbackFunction);
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[System.Runtime.InteropServices.DllImport("{{context.NativeLibraryName}}", CallingConvention=System.Runtime.InteropServices.CallingConvention.Cdecl)]
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private static extern {{csReturnType.AsInteropTypeReturn().GetFullyQualifiedName()}} {{invokeCallbackName}}({{string.Join(", ", invokeInteropParameters)}});
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private static unsafe extern {{csReturnType.AsInteropTypeReturn().GetFullyQualifiedName()}} {{invokeCallbackName}}({{string.Join(", ", invokeInteropParameters)}}, IntPtr* reinteropException);
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}
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[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
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private unsafe delegate IntPtr {{csBaseName}}Type(IntPtr callbackFunction);
@@ -165,12 +176,19 @@ private void Dispose(bool disposing)
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var interopParameters = new[] { (Name: "pCallbackFunction", CsType: CSharpType.FromSymbol(context, context.Compilation.GetSpecialType(SpecialType.System_IntPtr)), Type: CppType.VoidPointer, InteropType: CppType.VoidPointer) }.Concat(callbackParameters);
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var callParameters = callbackParameters.Select(p => p.Type.GetConversionFromInteropType(context, p.Name));
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CppType interopReturnType = returnType.AsInteropType();
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string resultImplementation = "";
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string returnImplementation = "return;";
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string returnDefault = "return;";
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if (invokeMethod.ReturnType.SpecialType != SpecialType.System_Void)
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{
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resultImplementation = "auto result = ";
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returnImplementation = $"return {returnType.GetConversionToInteropType(context, "result")};";
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if (interopReturnType.Flags.HasFlag(CppTypeFlags.Pointer))
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returnDefault = "return nullptr;";
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else
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returnDefault = $$"""return {{interopReturnType.GetFullyQualifiedName()}}();""";
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}
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result.CppImplementationInvoker.Functions.Add(new(
@@ -179,12 +197,29 @@ private void Dispose(bool disposing)
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#if defined(_WIN32)
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__declspec(dllexport)
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#endif
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{{returnType.AsInteropType().GetFullyQualifiedName()}} {{invokeCallbackName}}({{string.Join(", ", interopParameters.Select(p => $"{p.InteropType.GetFullyQualifiedName()} {p.Name}"))}}) {
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{{interopReturnType.GetFullyQualifiedName()}} {{invokeCallbackName}}({{string.Join(", ", interopParameters.Select(p => $"{p.InteropType.GetFullyQualifiedName()} {p.Name}").Concat(new[] { "void** reinteropException" }))}}) {
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auto pFunc = reinterpret_cast<std::function<{{itemType.GetFullyQualifiedName()}}::FunctionSignature>*>(pCallbackFunction);
184-
{{resultImplementation}}(*pFunc)({{string.Join(", ", callParameters)}});
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{{returnImplementation}}
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try {
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{{resultImplementation}}(*pFunc)({{string.Join(", ", callParameters)}});
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{{returnImplementation}}
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} catch (::DotNet::Reinterop::ReinteropNativeException& e) {
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*reinteropException = ::DotNet::Reinterop::ObjectHandle(e.GetDotNetException().GetHandle()).Release();
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{{returnDefault}}
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} catch (std::exception& e) {
209+
*reinteropException = ::DotNet::Reinterop::ReinteropException(::DotNet::System::String(e.what())).GetHandle().Release();
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{{returnDefault}}
211+
} catch (...) {
212+
*reinteropException = ::DotNet::Reinterop::ReinteropException(::DotNet::System::String("An unknown native exception occurred.")).GetHandle().Release();
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{{returnDefault}}
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}
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}
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"""));
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""",
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TypeDefinitionsReferenced: new[]
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{
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CppReinteropException.GetCppType(context),
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CSharpReinteropException.GetCppWrapperType(context),
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CppType.FromCSharp(context, context.Compilation.GetSpecialType(SpecialType.System_String))
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}));
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result.CppImplementationInvoker.Functions.Add(new(
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