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      1 /*
      2  * Copyright (c) Meta Platforms, Inc. and affiliates.
      3  * All rights reserved.
      4  *
      5  * This source code is licensed under both the BSD-style license (found in the
      6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
      7  * in the COPYING file in the root directory of this source tree).
      8  */
      9 #pragma once
     10 
     11 #include <utility>
     12 
     13 namespace pzstd {
     14 
     15 /**
     16  * Dismissable scope guard.
     17  * `Function` must be callable and take no parameters.
     18  * Unless `dismiss()` is called, the callable is executed upon destruction of
     19  * `ScopeGuard`.
     20  *
     21  * Example:
     22  *
     23  *   auto guard = makeScopeGuard([&] { cleanup(); });
     24  */
     25 template <typename Function>
     26 class ScopeGuard {
     27   Function function;
     28   bool dismissed;
     29 
     30  public:
     31   explicit ScopeGuard(Function&& function)
     32       : function(std::move(function)), dismissed(false) {}
     33 
     34   void dismiss() {
     35     dismissed = true;
     36   }
     37 
     38   ~ScopeGuard() noexcept {
     39     if (!dismissed) {
     40       function();
     41     }
     42   }
     43 };
     44 
     45 /// Creates a scope guard from `function`.
     46 template <typename Function>
     47 ScopeGuard<Function> makeScopeGuard(Function&& function) {
     48   return ScopeGuard<Function>(std::forward<Function>(function));
     49 }
     50 }
     51