1 files changed, 122 insertions, 0 deletions
diff --git a/include/qdotnetcallback.h b/include/qdotnetcallback.h
new file mode 100644
index 0000000..6efea1e
--- /dev/null
+++ b/include/qdotnetcallback.h
@@ -0,0 +1,122 @@
+/***************************************************************************************************
+ Copyright (C) 2023 The Qt Company Ltd.
+ SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+***************************************************************************************************/
+
+#pragma once
+
+#include "qdotnetfunction.h"
+
+#ifdef __GNUC__
+#   pragma GCC diagnostic push
+#   pragma GCC diagnostic ignored "-Wconversion"
+#endif
+#include <QMap>
+#ifdef __GNUC__
+#   pragma GCC diagnostic pop
+#endif
+
+#include <functional>
+
+class QDotNetCallbackBase
+{
+protected:
+    QDotNetCallbackBase() = default;
+public:
+    virtual ~QDotNetCallbackBase() = default;
+};
+
+template<typename TResult, typename... TArg>
+class QDotNetCallback : public QDotNetCallbackBase
+{
+public:
+    using ReturnType = typename QDotNetInbound<TResult>::TargetType;
+    using FunctionType = std::function<ReturnType(
+        typename QDotNetInbound<TArg>::TargetType... arg)>;
+
+    using OutboundType = typename QDotNetOutbound<TResult>::OutboundType;
+    using Delegate = OutboundType(QDOTNETFUNCTION_CALLTYPE *)(
+        QDotNetCallback *callback, quint64 key, typename QDotNetInbound<TArg>::InboundType...);
+
+    using CleanUp = void(QDOTNETFUNCTION_CALLTYPE *)(QDotNetCallback *callback, quint64 key);
+
+    QDotNetCallback(FunctionType function)
+        : function(function)
+    {}
+
+    ~QDotNetCallback() override = default;
+
+    static Delegate delegate()
+    {
+        return callbackDelegate;
+    }
+
+    static CleanUp cleanUp()
+    {
+        return callbackCleanUp;
+    }
+
+private:
+    struct Box
+    {
+        ReturnType returnValue;
+    };
+    QMap<quint64, Box *> boxes;
+
+    static OutboundType QDOTNETFUNCTION_CALLTYPE callbackDelegate(
+        QDotNetCallback *callback, quint64 key, typename QDotNetInbound<TArg>::InboundType... arg)
+    {
+        Box *box = callback->boxes[key] = new Box
+        {
+            callback->function(QDotNetInbound<TArg>::convert(arg)...)
+        };
+        const auto result = QDotNetOutbound<TResult>::convert(box->returnValue);
+        return result;
+    }
+
+    static void QDOTNETFUNCTION_CALLTYPE callbackCleanUp(QDotNetCallback *callback, quint64 key)
+    {
+        if (const Box *box = callback->boxes.take(key))
+            delete box;
+    }
+
+    FunctionType function = nullptr;
+};
+
+template<typename... TArg>
+class QDotNetCallback<void, TArg...> : public QDotNetCallbackBase
+{
+public:
+    using FunctionType = std::function<void(typename QDotNetOutbound<TArg>::SourceType... arg)>;
+
+    QDotNetCallback(FunctionType function)
+        : function(function)
+    {}
+
+    ~QDotNetCallback() override = default;
+
+    using Delegate = void(QDOTNETFUNCTION_CALLTYPE *)(
+        QDotNetCallback *callback, quint64 key, typename QDotNetInbound<TArg>::InboundType...);
+    static Delegate delegate()
+    {
+        return callbackDelegate;
+    }
+
+    using CleanUp = void(QDOTNETFUNCTION_CALLTYPE *)(QDotNetCallback *callback, quint64 key);
+    static CleanUp cleanUp()
+    {
+        return callbackCleanUp;
+    }
+
+private:
+    static void QDOTNETFUNCTION_CALLTYPE callbackDelegate(QDotNetCallback *callback, quint64 key,
+        typename QDotNetInbound<TArg>::InboundType... arg)
+    {
+        callback->function(QDotNetInbound<TArg>::convert(arg)...);
+    }
+
+    static void QDOTNETFUNCTION_CALLTYPE callbackCleanUp(QDotNetCallback *callback, quint64 key)
+    {}
+
+    FunctionType function = nullptr;
+};