generic-library/cxx
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Brought call_once variadic call up to current spec, which allows move-only functors and move-only arguments, but disallows functors with non-const lvalue reference parameters.

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@131414 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Howard Hinnant 2011-05-16 19:05:11 +00:00
parent 656bdc3667
commit ad935d583d
2 changed files with 61 additions and 4 deletions
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45
include/mutex
View File

@ -175,6 +175,9 @@ template<class Callable, class ...Args>
#include <__config> #include <__config>
#include <__mutex_base> #include <__mutex_base>
#include <functional> #include <functional>
#ifndef _LIBCPP_HAS_NO_VARIADICS
#include <tuple>
#endif
#pragma GCC system_header #pragma GCC system_header
@ -455,6 +458,39 @@ private:
#endif // _LIBCPP_HAS_NO_VARIADICS #endif // _LIBCPP_HAS_NO_VARIADICS
}; };
#ifndef _LIBCPP_HAS_NO_VARIADICS
template <class _F>
class __call_once_param
{
_F __f_;
public:
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
_LIBCPP_INLINE_VISIBILITY
explicit __call_once_param(_F&& __f) : __f_(_STD::move(__f)) {}
#else
_LIBCPP_INLINE_VISIBILITY
explicit __call_once_param(const _F& __f) : __f_(__f) {}
#endif
_LIBCPP_INLINE_VISIBILITY
void operator()()
{
typedef typename __make_tuple_indices<tuple_size<_F>::value, 1>::type _Index;
__execute(_Index());
}
private:
template <size_t ..._Indices>
_LIBCPP_INLINE_VISIBILITY
void __execute(__tuple_indices<_Indices...>)
{
_STD::move(_STD::get<0>(__f_))(_STD::move(_STD::get<_Indices>(__f_))...);
}
};
#else
template <class _F> template <class _F>
class __call_once_param class __call_once_param
{ {
@ -475,6 +511,8 @@ public:
} }
}; };
#endif
template <class _F> template <class _F>
void void
__call_once_proxy(void* __vp) __call_once_proxy(void* __vp)
@ -494,10 +532,9 @@ call_once(once_flag& __flag, _Callable&& __func, _Args&&... __args)
{ {
if (__builtin_expect(__flag.__state_ , ~0ul) != ~0ul) if (__builtin_expect(__flag.__state_ , ~0ul) != ~0ul)
{ {
typedef decltype(std::bind(std::forward<_Callable>(__func), typedef tuple<typename decay<_Callable>::type, typename decay<_Args>::type...> _G;
std::forward<_Args>(__args)...)) _G; __call_once_param<_G> __p(_G(__decay_copy(_STD::forward<_Callable>(__func)),
__call_once_param<_G> __p(std::bind(std::forward<_Callable>(__func), __decay_copy(_STD::forward<_Args>(__args))...));
std::forward<_Args>(__args)...));
__call_once(__flag.__state_, &__p, &__call_once_proxy<_G>); __call_once(__flag.__state_, &__p, &__call_once_proxy<_G>);
} }
} }

20
test/thread/thread.mutex/thread.once/thread.once.callonce/call_once.pass.cpp
View File

@ -129,6 +129,22 @@ void f42()
std::call_once(flg41, init41); std::call_once(flg41, init41);
} }
#ifndef _LIBCPP_HAS_NO_VARIADICS
class MoveOnly
{
MoveOnly(const MoveOnly&);
public:
MoveOnly() {}
MoveOnly(MoveOnly&&) {}
void operator()(MoveOnly&&)
{
}
};
#endif
int main() int main()
{ {
// check basic functionality // check basic functionality
@ -174,5 +190,9 @@ int main()
t1.join(); t1.join();
assert(init2::called == 5); assert(init2::called == 5);
} }
{
std::once_flag f;
std::call_once(f, MoveOnly(), MoveOnly());
}
#endif // _LIBCPP_HAS_NO_VARIADICS #endif // _LIBCPP_HAS_NO_VARIADICS
} }