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feat: extend ScopeGuard with success and failure overloads (#384)

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This commit is contained in:
Stanislav Angelovič
2023-12-05 18:16:45 +01:00
committed by GitHub
parent 934d51fa8a
commit d80483cdc0
1 changed files with 78 additions and 40 deletions
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118
src/ScopeGuard.h
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@ -55,62 +55,104 @@
// return; // exiting scope normally // return; // exiting scope normally
// } // }
#define SCOPE_EXIT \ #define SCOPE_EXIT \
auto ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE) \ auto ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE) \
= ::sdbus::internal::detail::ScopeGuardOnExit() + [&]() \ = ::sdbus::internal::ScopeGuardOnExitTag{} + [&]() \
/**/ /**/
#define SCOPE_EXIT_NAMED(NAME) \
#define SCOPE_EXIT_NAMED(NAME) \ auto NAME \
auto NAME \ = ::sdbus::internal::ScopeGuardOnExitTag{} + [&]() \
= ::sdbus::internal::detail::ScopeGuardOnExit() + [&]() \ /**/
#define SCOPE_EXIT_SUCCESS \
auto ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE) \
= ::sdbus::internal::ScopeGuardOnExitSuccessTag{} + [&]() \
/**/
#define SCOPE_EXIT_SUCCESS_NAMED(NAME) \
auto NAME \
= ::sdbus::internal::ScopeGuardOnExitSuccessTag{} + [&]() \
/**/
#define SCOPE_EXIT_FAILURE \
auto ANONYMOUS_VARIABLE(SCOPE_EXIT_STATE) \
= ::sdbus::internal::ScopeGuardOnExitFailureTag{} + [&]() \
/**/
#define SCOPE_EXIT_FAILURE_NAMED(NAME) \
auto NAME \
= ::sdbus::internal::ScopeGuardOnExitFailureTag{} + [&]() \
/**/ /**/
namespace sdbus::internal { namespace sdbus::internal {
template <class _Fun> struct ScopeGuardOnExitTag
{
static bool holds(int /*originalExceptions*/)
{
return true; // Always holds
}
};
struct ScopeGuardOnExitSuccessTag
{
static bool holds(int originalExceptions)
{
return originalExceptions == std::uncaught_exceptions(); // Only holds when no exception occurred within the scope
}
};
struct ScopeGuardOnExitFailureTag
{
static bool holds(int originalExceptions)
{
return originalExceptions != std::uncaught_exceptions(); // Only holds when an exception occurred within the scope
}
};
template <class _Fun, typename _Tag>
class ScopeGuard class ScopeGuard
{ {
_Fun fnc_;
bool active_;
public: public:
ScopeGuard(_Fun f) ScopeGuard(_Fun f) : fnc_(std::move(f))
: fnc_(std::move(f))
, active_(true)
{ {
} }
~ScopeGuard()
ScopeGuard() = delete;
ScopeGuard(const ScopeGuard&) = delete;
ScopeGuard& operator=(const ScopeGuard&) = delete;
ScopeGuard(ScopeGuard&& rhs) : fnc_(std::move(rhs.fnc_)), active_(rhs.active_), exceptions_(rhs.exceptions_)
{ {
if (active_) rhs.dismiss();
fnc_();
} }
void dismiss() void dismiss()
{ {
active_ = false; active_ = false;
} }
ScopeGuard() = delete;
ScopeGuard(const ScopeGuard&) = delete; ~ScopeGuard()
ScopeGuard& operator=(const ScopeGuard&) = delete;
ScopeGuard(ScopeGuard&& rhs)
: fnc_(std::move(rhs.fnc_))
, active_(rhs.active_)
{ {
rhs.dismiss(); if (active_ && _Tag::holds(exceptions_))
fnc_();
} }
private:
_Fun fnc_;
int exceptions_{std::uncaught_exceptions()};
bool active_{true};
}; };
namespace detail template <typename _Fun>
ScopeGuard<_Fun, ScopeGuardOnExitTag> operator+(ScopeGuardOnExitTag, _Fun&& fnc)
{ {
enum class ScopeGuardOnExit return ScopeGuard<_Fun, ScopeGuardOnExitTag>(std::forward<_Fun>(fnc));
{ }
};
// Helper function to auto-deduce type of the callable entity template <typename _Fun>
template <typename _Fun> ScopeGuard<_Fun, ScopeGuardOnExitSuccessTag> operator+(ScopeGuardOnExitSuccessTag, _Fun&& fnc)
ScopeGuard<_Fun> operator+(ScopeGuardOnExit, _Fun&& fnc) {
{ return ScopeGuard<_Fun, ScopeGuardOnExitSuccessTag>(std::forward<_Fun>(fnc));
return ScopeGuard<_Fun>(std::forward<_Fun>(fnc)); }
}
template <typename _Fun>
ScopeGuard<_Fun, ScopeGuardOnExitFailureTag> operator+(ScopeGuardOnExitFailureTag, _Fun&& fnc)
{
return ScopeGuard<_Fun, ScopeGuardOnExitFailureTag>(std::forward<_Fun>(fnc));
} }
} }
@ -119,13 +161,9 @@ namespace sdbus::internal {
#define CONCATENATE(s1, s2) CONCATENATE_IMPL(s1, s2) #define CONCATENATE(s1, s2) CONCATENATE_IMPL(s1, s2)
#ifdef __COUNTER__ #ifdef __COUNTER__
#define ANONYMOUS_VARIABLE(str) \ #define ANONYMOUS_VARIABLE(str) CONCATENATE(str, __COUNTER__)
CONCATENATE(str, __COUNTER__) \
/**/
#else #else
#define ANONYMOUS_VARIABLE(str) \ #define ANONYMOUS_VARIABLE(str) CONCATENATE(str, __LINE__)
CONCATENATE(str, __LINE__) \
/**/
#endif #endif
#endif /* SDBUS_CPP_INTERNAL_SCOPEGUARD_H_ */ #endif /* SDBUS_CPP_INTERNAL_SCOPEGUARD_H_ */