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1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SkScopeExit_DEFINED
9 #define SkScopeExit_DEFINED
10 
11 #include "SkTypes.h"
12 
13 /**
14  * SK_AT_SCOPE_EXIT(stmt) evaluates stmt when the current scope ends.
15  *
16  * E.g.
17  *    {
18  *        int x = 5;
19  *        {
20  *           SK_AT_SCOPE_EXIT(x--);
21  *           SkASSERT(x == 5);
22  *        }
23  *        SkASSERT(x == 4);
24  *    }
25  */
26 template <typename Fn>
27 class SkScopeExit {
28 public:
SkScopeExit(Fn f)29     SkScopeExit(Fn f) : fFn(std::move(f)) {}
~SkScopeExit()30     ~SkScopeExit() { fFn(); }
31 
32 private:
33     Fn fFn;
34 
35     SkScopeExit(           const SkScopeExit& ) = delete;
36     SkScopeExit& operator=(const SkScopeExit& ) = delete;
37     SkScopeExit(                 SkScopeExit&&) = delete;
38     SkScopeExit& operator=(      SkScopeExit&&) = delete;
39 };
40 
41 template <typename Fn>
SkMakeScopeExit(Fn && fn)42 inline SkScopeExit<Fn> SkMakeScopeExit(Fn&& fn) {
43     return {std::move(fn)};
44 }
45 
46 #define SK_AT_SCOPE_EXIT(stmt)                              \
47     SK_UNUSED auto&& SK_MACRO_APPEND_LINE(at_scope_exit_) = \
48         SkMakeScopeExit([&]() { stmt; });
49 
50 #endif  // SkScopeExit_DEFINED
51