From ca697d6ca0c49f91ca13c72f0bb870d297b26767 Mon Sep 17 00:00:00 2001 From: Lexi Winter Date: Wed, 2 Jul 2025 03:05:56 +0100 Subject: move guard to util --- nihil.util/guard.ccm | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 nihil.util/guard.ccm (limited to 'nihil.util/guard.ccm') diff --git a/nihil.util/guard.ccm b/nihil.util/guard.ccm new file mode 100644 index 0000000..77394fc --- /dev/null +++ b/nihil.util/guard.ccm @@ -0,0 +1,41 @@ +// This source code is released into the public domain. +export module nihil.util:guard; + +import nihil.std; + +namespace nihil { + +// guard: invoke a callable when this object is destroyed; this is similar to +// scope_exit from the library fundamentals TS, which LLVM doesn't implement. +export template +struct guard final { + // Initialise the guard with a callable we will invoke later. + explicit guard(F func) : m_func(std::move(func)) {} + + // We are being destroyed, so call the callable. + // If the callable throws, std::terminate() will be called. + ~guard() + { + if (m_func) + std::invoke(*m_func); + } + + // Release the guard. This turns the destructor into a no-op. + auto release(this guard &self) noexcept -> void + { + self.m_func.reset(); + } + + // Not default-constructible, movable or copyable. + guard() = delete; + guard(guard const &) = delete; + guard(guard &&) noexcept = delete; + auto operator=(this guard &, guard const &) -> guard & = delete; + auto operator=(this guard &, guard &&) noexcept -> guard & = delete; + +private: + // The callable to be invoked when we are destroyed. + std::optional m_func; +}; + +} // namespace nihil -- cgit v1.2.3