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tdutils/td/utils/ScopeGuard.h

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library 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 Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#pragma once
+
+#include "td/utils/common.h"
+
+#include <cstdlib>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+namespace td {
+
+class Guard {
+ public:
+  Guard() = default;
+  Guard(const Guard &other) = delete;
+  Guard &operator=(const Guard &other) = delete;
+  Guard(Guard &&other) = default;
+  Guard &operator=(Guard &&other) = default;
+  virtual ~Guard() = default;
+  virtual void dismiss() {
+    std::abort();
+  }
+};
+
+template <class FunctionT>
+class LambdaGuard : public Guard {
+ public:
+  explicit LambdaGuard(const FunctionT &func) : func_(func) {
+  }
+  explicit LambdaGuard(FunctionT &&func) : func_(std::move(func)) {
+  }
+  LambdaGuard(const LambdaGuard &other) = delete;
+  LambdaGuard &operator=(const LambdaGuard &other) = delete;
+  LambdaGuard(LambdaGuard &&other) : func_(std::move(other.func_)), dismissed_(other.dismissed_) {
+    other.dismissed_ = true;
+  }
+  LambdaGuard &operator=(LambdaGuard &&other) = delete;
+
+  void dismiss() {
+    dismissed_ = true;
+  }
+
+  ~LambdaGuard() {
+    if (!dismissed_) {
+      func_();
+    }
+  }
+
+ private:
+  FunctionT func_;
+  bool dismissed_ = false;
+};
+
+template <class F>
+unique_ptr<Guard> create_lambda_guard(F &&f) {
+  return make_unique<LambdaGuard<F>>(std::forward<F>(f));
+}
+template <class F>
+std::shared_ptr<Guard> create_shared_lambda_guard(F &&f) {
+  return std::make_shared<LambdaGuard<F>>(std::forward<F>(f));
+}
+
+enum class ScopeExit {};
+template <class FunctionT>
+auto operator+(ScopeExit, FunctionT &&func) {
+  return LambdaGuard<std::decay_t<FunctionT>>(std::forward<FunctionT>(func));
+}
+
+}  // namespace td
+
+#define SCOPE_EXIT auto TD_CONCAT(SCOPE_EXIT_VAR_, __LINE__) = ::td::ScopeExit() + [&]()