Keep reference to generic server function delegates so they don't get…

… GCed and crash the application
huysentruitw · Jan 20, 2022 · 65dfaa8 · 65dfaa8
1 parent 4c3fee9
commit 65dfaa8
Showing 1 changed file with 15 additions and 4 deletions.
diff --git a/src/SapNwRfc/SapServer.cs b/src/SapNwRfc/SapServer.cs
@@ -94,13 +94,24 @@ public static void InstallGenericServerFunctionHandler(Func<string, SapAttribute
             InstallGenericServerFunctionHandler(new RfcInterop(), getFunctionMetadata, action);
         }
 
+        // We keep a reference to the current server function delegates so they don't get GCed
+        // Otherwise the application crashes as the delegate passed into native does no longer exists in managed
+#pragma warning disable SA1306 // Field names should begin with lower-case letter
+        private static RfcInterop.RfcServerFunction CurrentServerFunction;
+        private static RfcInterop.RfcFunctionDescriptionCallback CurrentFunctionDescriptionCallback;
+#pragma warning restore SA1306 // Field names should begin with lower-case letter
+
         private static void InstallGenericServerFunctionHandler(RfcInterop interop, Func<string, SapAttributes, ISapFunctionMetadata> getFunctionMetadata, Action<ISapServerConnection, ISapServerFunction> action)
         {
+            CurrentServerFunction = (IntPtr connectionHandle, IntPtr functionHandle, out RfcErrorInfo errorInfo)
+                    => HandleGenericFunction(interop, action, connectionHandle, functionHandle, out errorInfo);
+
+            CurrentFunctionDescriptionCallback = (string functionName, RfcAttributes attributes, ref IntPtr funcDescHandle)
+                    => HandleGenericMetadata(functionName, attributes, out funcDescHandle, getFunctionMetadata);
+
             RfcResultCode resultCode = interop.InstallGenericServerFunction(
-                serverFunction: (IntPtr connectionHandle, IntPtr functionHandle, out RfcErrorInfo errorInfo)
-                    => HandleGenericFunction(interop, action, connectionHandle, functionHandle, out errorInfo),
-                funcDescPointer: (string functionName, RfcAttributes attributes, ref IntPtr funcDescHandle)
-                    => HandleGenericMetadata(functionName, attributes, out funcDescHandle, getFunctionMetadata),
+                serverFunction: CurrentServerFunction,
+                funcDescPointer: CurrentFunctionDescriptionCallback,
                 out RfcErrorInfo installFunctionErrorInfo);
 
             resultCode.ThrowOnError(installFunctionErrorInfo);