1 files changed, 194 insertions, 0 deletions
diff --git a/src/core/function/basic/GpgFunctionObject.h b/src/core/function/basic/GpgFunctionObject.h
new file mode 100644
index 00000000..1ea352b6
--- /dev/null
+++ b/src/core/function/basic/GpgFunctionObject.h
@@ -0,0 +1,194 @@
+/**
+ * Copyright (C) 2021 Saturneric <[email protected]>
+ *
+ * This file is part of GpgFrontend.
+ *
+ * GpgFrontend is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GpgFrontend is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GpgFrontend. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * The initial version of the source code is inherited from
+ * the gpg4usb project, which is under GPL-3.0-or-later.
+ *
+ * All the source code of GpgFrontend was modified and released by
+ * Saturneric <[email protected]> starting on May 12, 2021.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#pragma once
+
+#include <mutex>
+#include <stdexcept>
+
+#include "core/GpgFrontendCoreExport.h"
+#include "core/function/basic/ChannelObject.h"
+#include "core/function/basic/SingletonStorage.h"
+#include "core/function/basic/SingletonStorageCollection.h"
+#include "core/utils/MemoryUtils.h"
+
+namespace GpgFrontend {
+
+auto GPGFRONTEND_CORE_EXPORT GetChannelObjectInstance(
+    const std::type_info& type, int channel) -> ChannelObject*;
+
+auto GPGFRONTEND_CORE_EXPORT CreateChannelObjectInstance(
+    const std::type_info& type, int channel,
+    SecureUniquePtr<ChannelObject> channel_object) -> ChannelObject*;
+
+auto GPGFRONTEND_CORE_EXPORT
+GetGlobalFunctionObjectTypeLock(const std::type_info& type) -> std::mutex&;
+
+/**
+ * @brief
+ *
+ * @tparam T
+ */
+template <typename T>
+class SingletonFunctionObject : public ChannelObject {
+ public:
+  /**
+   * @brief prohibit copy
+   *
+   */
+  SingletonFunctionObject(const SingletonFunctionObject<T>&) = delete;
+
+  /**
+   * @brief prohibit copy
+   *
+   * @return SingletonFunctionObject&
+   */
+  auto operator=(const SingletonFunctionObject<T>&)
+      -> SingletonFunctionObject& = delete;
+
+  /**
+   * @brief Get the Instance object
+   *
+   * @param channel
+   * @return T&
+   */
+  static auto GetInstance(int channel = GpgFrontend::kGpgFrontendDefaultChannel)
+      -> T& {
+    static_assert(std::is_base_of_v<SingletonFunctionObject<T>, T>,
+                  "T not derived from SingletonFunctionObject<T>");
+
+    const auto& type = typeid(T);
+    std::lock_guard<std::mutex> guard(GetGlobalFunctionObjectTypeLock(type));
+    auto* channel_object = GetChannelObjectInstance(type, channel);
+    if (channel_object == nullptr) {
+      channel_object = CreateChannelObjectInstance(
+          type, channel,
+          ConvertToChannelObjectPtr(SecureCreateUniqueObject<T>(channel)));
+    }
+    return *static_cast<T*>(channel_object);
+  }
+
+  /**
+   * @brief Create a Instance object
+   *
+   * @param channel
+   * @param factory
+   * @return T&
+   */
+  static auto CreateInstance(
+      int channel, const std::function<ChannelObjectPtr(void)>& factory) -> T& {
+    static_assert(std::is_base_of_v<SingletonFunctionObject<T>, T>,
+                  "T not derived from SingletonFunctionObject<T>");
+
+    const auto& type = typeid(T);
+    std::lock_guard<std::mutex> guard(GetGlobalFunctionObjectTypeLock(type));
+    return *static_cast<T*>(
+        CreateChannelObjectInstance(type, channel, factory()));
+  }
+
+  /**
+   * @brief
+   *
+   * @param channel
+   * @return T&
+   */
+  static void ReleaseChannel(int channel) {
+    SingletonStorageCollection::GetInstance(false)
+        ->GetSingletonStorage(typeid(T))
+        ->ReleaseChannel(channel);
+  }
+
+  /**
+   * @brief Get the Default Channel object
+   *
+   * @return int
+   */
+  static auto GetDefaultChannel() -> int {
+    return ChannelObject::GetDefaultChannel();
+  }
+
+  /**
+   * @brief Get the Channel object
+   *
+   * @return int
+   */
+  [[nodiscard]] auto GetChannel() const -> int {
+    return ChannelObject::GetChannel();
+  }
+
+  /**
+   * @brief Get all the channel ids
+   *
+   * @return std::vector<int>
+   */
+  static auto GetAllChannelId() -> std::vector<int> {
+    return SingletonStorageCollection::GetInstance(false)
+        ->GetSingletonStorage(typeid(T))
+        ->GetAllChannelId();
+  }
+
+  /**
+   * @brief Construct a new Singleton Function Object object
+   *
+   */
+  SingletonFunctionObject(T&&) = delete;
+
+  /**
+   * @brief Construct a new Singleton Function Object object
+   *
+   */
+  SingletonFunctionObject(const T&) = delete;
+
+  /**
+   * @brief
+   *
+   */
+  void operator=(const T&) = delete;
+
+ protected:
+  /**
+   * @brief Construct a new Singleton Function Object object
+   *
+   */
+  SingletonFunctionObject() = default;
+
+  /**
+   * @brief Construct a new Singleton Function Object object
+   *
+   * @param channel
+   */
+  explicit SingletonFunctionObject(int channel)
+      : ChannelObject(channel, typeid(T).name()) {}
+
+  /**
+   * @brief Destroy the Singleton Function Object object
+   *
+   */
+  virtual ~SingletonFunctionObject() = default;
+};
+}  // namespace GpgFrontend