LLVM  8.0.0svn
ScopeExit.h
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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>
32  explicit scope_exit(Fp &&F) : ExitFunction(std::forward<Fp>(F)) {}
33 
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 
42  void release() { Engaged = false; }
43 
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>
59 make_scope_exit(Callable &&F) {
61  std::forward<Callable>(F));
62 }
63 
64 } // end namespace llvm
65 
66 #endif
scope_exit(scope_exit &&Rhs)
Definition: ScopeExit.h:34
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
LLVM_NODISCARD detail::scope_exit< typename std::decay< Callable >::type > make_scope_exit(Callable &&F)
Definition: ScopeExit.h:59
F(f)
#define LLVM_NODISCARD
LLVM_NODISCARD - Warn if a type or return value is discarded.
Definition: Compiler.h:129
Definition: BitVector.h:938
scope_exit & operator=(scope_exit &&)=delete