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| -rw-r--r-- | Makefile.am | 1 | ||||
| -rw-r--r-- | src/util/ScopeExit.hxx | 89 |
2 files changed, 90 insertions, 0 deletions
diff --git a/Makefile.am b/Makefile.am index 2eed31d9f..156655671 100644 --- a/Makefile.am +++ b/Makefile.am @@ -359,6 +359,7 @@ libutil_a_SOURCES = \ src/util/Clamp.hxx \ src/util/Alloc.cxx src/util/Alloc.hxx \ src/util/VarSize.hxx \ + src/util/ScopeExit.hxx \ src/util/Error.cxx src/util/Error.hxx \ src/util/Domain.hxx \ src/util/ReusableArray.hxx \ diff --git a/src/util/ScopeExit.hxx b/src/util/ScopeExit.hxx new file mode 100644 index 000000000..0ec65cd9b --- /dev/null +++ b/src/util/ScopeExit.hxx @@ -0,0 +1,89 @@ +/* + * Copyright (C) 2015 Max Kellermann <max@duempel.org> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * - Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * - Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the + * distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED + * OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef SCOPE_EXIT_HXX +#define SCOPE_EXIT_HXX + +#include "Compiler.h" + +#include <utility> + +/** + * Internal class. Do not use directly. + */ +template<typename F> +class ScopeExitGuard : F { + bool enabled = true; + +public: + explicit ScopeExitGuard(F &&f):F(std::forward<F>(f)) {} + + ScopeExitGuard(ScopeExitGuard &&src) + :F(std::move(src)) { + src.enabled = false; + } + + ~ScopeExitGuard() { + if (enabled) + F::operator()(); + } + + ScopeExitGuard(const ScopeExitGuard &) = delete; + ScopeExitGuard &operator=(const ScopeExitGuard &) = delete; +}; + +/** + * Internal class. Do not use directly. + */ +struct ScopeExitTag { + /* this operator is a trick so we don't need to close + parantheses at the end of the expression AtScopeExit() + call */ + template<typename F> + ScopeExitGuard<F> operator+(F &&f) { + return ScopeExitGuard<F>(std::forward<F>(f)); + } +}; + +#define ScopeExitCat(a, b) a ## b +#define ScopeExitName(line) ScopeExitCat(at_scope_exit_, line) + +/** + * Call the block after this macro at the end of the current scope. + * Parameters are lambda captures. + * + * This is exception-safe, however the given code block must not throw + * exceptions. + * + * This attempts to be a better boost/scope_exit.hpp, without all of + * Boost's compile-time and runtime bloat. + */ +#define AtScopeExit(...) auto ScopeExitName(__LINE__) = ScopeExitTag() + [__VA_ARGS__]() + +#endif |