mirror of https://gitee.com/bigwinds/arangodb
72 lines
2.4 KiB
C++
72 lines
2.4 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2019 ArangoDB GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Tobias Gödderz
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_CLUSTER_CALLBACKGUARD_H
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#define ARANGOD_CLUSTER_CALLBACKGUARD_H
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#include <functional>
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#include "Cluster/ClusterTypes.h"
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namespace arangodb {
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namespace cluster {
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/// @brief If constructed with a callback, the given callback will be called
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/// exactly once: Either during destruction, or when the object is overwritten
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/// (via operator=()), or when it's explicitly cleared. It's not copyable,
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/// but movable.
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class CallbackGuard {
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public:
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// Calls the callback given callback upon destruction.
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// Allows only move semantics and no copy semantics.
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CallbackGuard();
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// IMPORTANT NOTE:
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// The passed callback should not throw exceptions, they will not be caught
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// here, but thrown by the destructor!
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explicit CallbackGuard(std::function<void(void)> callback);
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~CallbackGuard();
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// Note that the move constructor of std::function is not noexcept until
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// C++20. Thus we cannot mark the constructors here noexcept.
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// NOLINTNEXTLINE(hicpp-noexcept-move,performance-noexcept-move-constructor)
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CallbackGuard(CallbackGuard&& other);
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// operator= additionally calls the _callback, and this can also throw.
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// NOLINTNEXTLINE(hicpp-noexcept-move,performance-noexcept-move-constructor)
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CallbackGuard& operator=(CallbackGuard&&);
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CallbackGuard(CallbackGuard const&) = delete;
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CallbackGuard& operator=(CallbackGuard const&) = delete;
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/// @brief Call the contained callback, then delete it.
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void callAndClear();
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private:
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void call();
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std::function<void(void)> _callback;
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};
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}}
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#endif
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