llvm-project/libcxx/include/__algorithm/ranges_replace_if.h
Louis Dionne 7b4622514d
[libc++] Fix missing and incorrect push/pop macros (#79204)
We recently noticed that the unwrap_iter.h file was pushing macros, but
it was pushing them again instead of popping them at the end of the
file. This led to libc++ basically swallowing any custom definition of
these macros in user code:

    #define min HELLO
    #include <algorithm>
    // min is not HELLO anymore, it's not defined

While investigating this issue, I noticed that our push/pop pragmas were
actually entirely wrong too. Indeed, instead of pushing macros like
`move`, we'd push `move(int, int)` in the pragma, which is not a valid
macro name. As a result, we would not actually push macros like `move`
-- instead we'd simply undefine them. This led to the following code not
working:

    #define move HELLO
    #include <algorithm>
    // move is not HELLO anymore

Fixing the pragma push/pop incantations led to a cascade of issues
because we use identifiers like `move` in a large number of places, and
all of these headers would now need to do the push/pop dance.

This patch fixes all these issues. First, it adds a check that we don't
swallow important names like min, max, move or refresh as explained
above. This is done by augmenting the existing
system_reserved_names.gen.py test to also check that the macros are what
we expect after including each header.

Second, it fixes the push/pop pragmas to work properly and adds missing
pragmas to all the files I could detect a failure in via the newly added
test.

rdar://121365472
2024-01-25 15:48:46 -05:00

82 lines
2.6 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_RANGES_REPLACE_IF_H
#define _LIBCPP___ALGORITHM_RANGES_REPLACE_IF_H
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
#include <__iterator/concepts.h>
#include <__iterator/projected.h>
#include <__ranges/access.h>
#include <__ranges/concepts.h>
#include <__ranges/dangling.h>
#include <__utility/move.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
#if _LIBCPP_STD_VER >= 20
_LIBCPP_BEGIN_NAMESPACE_STD
namespace ranges {
template <class _Iter, class _Sent, class _Type, class _Proj, class _Pred>
_LIBCPP_HIDE_FROM_ABI constexpr _Iter
__replace_if_impl(_Iter __first, _Sent __last, _Pred& __pred, const _Type& __new_value, _Proj& __proj) {
for (; __first != __last; ++__first) {
if (std::invoke(__pred, std::invoke(__proj, *__first)))
*__first = __new_value;
}
return __first;
}
namespace __replace_if {
struct __fn {
template <input_iterator _Iter,
sentinel_for<_Iter> _Sent,
class _Type,
class _Proj = identity,
indirect_unary_predicate<projected<_Iter, _Proj>> _Pred>
requires indirectly_writable<_Iter, const _Type&>
_LIBCPP_HIDE_FROM_ABI constexpr _Iter
operator()(_Iter __first, _Sent __last, _Pred __pred, const _Type& __new_value, _Proj __proj = {}) const {
return ranges::__replace_if_impl(std::move(__first), std::move(__last), __pred, __new_value, __proj);
}
template <input_range _Range,
class _Type,
class _Proj = identity,
indirect_unary_predicate<projected<iterator_t<_Range>, _Proj>> _Pred>
requires indirectly_writable<iterator_t<_Range>, const _Type&>
_LIBCPP_HIDE_FROM_ABI constexpr borrowed_iterator_t<_Range>
operator()(_Range&& __range, _Pred __pred, const _Type& __new_value, _Proj __proj = {}) const {
return ranges::__replace_if_impl(ranges::begin(__range), ranges::end(__range), __pred, __new_value, __proj);
}
};
} // namespace __replace_if
inline namespace __cpo {
inline constexpr auto replace_if = __replace_if::__fn{};
} // namespace __cpo
} // namespace ranges
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STD_VER >= 20
_LIBCPP_POP_MACROS
#endif // _LIBCPP___ALGORITHM_RANGES_REPLACE_IF_H