1 //===- llvm/ADT/ScopeExit.h - Execute code at scope exit --------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines the make_scope_exit function, which executes user-defined 11 // cleanup logic at scope exit. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_ADT_SCOPE_EXIT_H 16 #define LLVM_ADT_SCOPE_EXIT_H 17 18 #include "llvm/Support/Compiler.h" 19 20 #include <type_traits> 21 #include <utility> 22 23 namespace llvm { 24 namespace detail { 25 26 template <typename Callable> class scope_exit { 27 Callable ExitFunction; 28 bool Engaged = true; // False once moved-from or release()d. 29 30 public: 31 template <typename Fp> scope_exit(Fp && F)32 explicit scope_exit(Fp &&F) : ExitFunction(std::forward<Fp>(F)) {} 33 scope_exit(scope_exit && Rhs)34 scope_exit(scope_exit &&Rhs) 35 : ExitFunction(std::move(Rhs.ExitFunction)), Engaged(Rhs.Engaged) { 36 Rhs.release(); 37 } 38 scope_exit(const scope_exit &) = delete; 39 scope_exit &operator=(scope_exit &&) = delete; 40 scope_exit &operator=(const scope_exit &) = delete; 41 release()42 void release() { Engaged = false; } 43 ~scope_exit()44 ~scope_exit() { 45 if (Engaged) 46 ExitFunction(); 47 } 48 }; 49 50 } // end namespace detail 51 52 // Keeps the callable object that is passed in, and execute it at the 53 // destruction of the returned object (usually at the scope exit where the 54 // returned object is kept). 55 // 56 // Interface is specified by p0052r2. 57 template <typename Callable> 58 LLVM_NODISCARD detail::scope_exit<typename std::decay<Callable>::type> make_scope_exit(Callable && F)59make_scope_exit(Callable &&F) { 60 return detail::scope_exit<typename std::decay<Callable>::type>( 61 std::forward<Callable>(F)); 62 } 63 64 } // end namespace llvm 65 66 #endif 67