First release of open-appsec source code

core/include/general/singleton.h

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+// Copyright (C) 2022 Check Point Software Technologies Ltd. All rights reserved.
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef __SINGLETON_H__
+#define __SINGLETON_H__
+
+#include <typeinfo>
+#include <typeindex>
+#include <map>
+#include <set>
+#include <memory>
+
+#include "common.h"
+
+class Singleton
+{
+public:
+    template <class I_Face>
+    class Provide;
+
+    template <class I_Face>
+    class Consume;
+
+    template <typename T>
+    static bool exists();
+
+    // Dealing with owned singletons - see advanced topics.
+    class OwnedSingleton;
+
+    template <typename DerivedFromOwnedSingleton>
+    static DerivedFromOwnedSingleton * getOwned();
+
+    template <typename DerivedFromOwnedSingleton>
+    static bool existsOwned();
+
+    template <typename DerivedFromOwnedSingleton, typename ... BuildArgs>
+    static void newOwned(BuildArgs ... args);
+
+    template <typename DerivedFromOwnedSingleton>
+    static void deleteOwned();
+
+    template <typename DerivedFromOwnedSingleton>
+    static void setOwned(std::unique_ptr<DerivedFromOwnedSingleton> &&ptr);
+
+private:
+    Singleton() {}
+
+    template <typename I_Face>
+    static I_Face * get();
+
+    static void registerSingleton(std::type_index type, void *ptr);
+    static void unregisterSingleton(std::type_index type, void *ptr);
+    static void * get(const std::type_index &index);
+    static bool exists(const std::type_index &index);
+
+    static std::map<std::type_index, std::set<void *>> singles;
+    static std::map<std::type_index, std::unique_ptr<OwnedSingleton>> owned_singles;
+};
+
+template <typename Component, typename Interface>
+Interface * getInterface();
+
+#include "impl/singleton.h"
+
+#endif // __SINGLETON_H__