* [committed] libstdc++: Add comparisons to std::default_sentinel_t (LWG 3719)
@ 2022-08-04 18:38 Jonathan Wakely
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From: Jonathan Wakely @ 2022-08-04 18:38 UTC (permalink / raw)
To: libstdc++, gcc-patches
Tested powerpc64le-linux, pushed to trunk.
-- >8 --
This library defect was recently approved for C++23.
libstdc++-v3/ChangeLog:
* include/bits/fs_dir.h (directory_iterator): Add comparison
with std::default_sentinel_t. Remove redundant operator!= for
C++20.
* (recursive_directory_iterator): Likewise.
* include/bits/iterator_concepts.h [!__cpp_lib_concepts]
(default_sentinel_t, default_sentinel): Define even if concepts
are not supported.
* include/bits/regex.h (regex_iterator): Add comparison with
std::default_sentinel_t. Remove redundant operator!= for C++20.
(regex_token_iterator): Likewise.
(regex_token_iterator::_M_end_of_seq()): Add noexcept.
* testsuite/27_io/filesystem/iterators/lwg3719.cc: New test.
* testsuite/28_regex/iterators/regex_iterator/lwg3719.cc:
New test.
* testsuite/28_regex/iterators/regex_token_iterator/lwg3719.cc:
New test.
---
libstdc++-v3/include/bits/fs_dir.h | 33 ++++++++++++----
libstdc++-v3/include/bits/iterator_concepts.h | 28 ++++++++++---
libstdc++-v3/include/bits/regex.h | 24 +++++++++++-
.../27_io/filesystem/iterators/lwg3719.cc | 39 +++++++++++++++++++
.../iterators/regex_iterator/lwg3719.cc | 29 ++++++++++++++
.../iterators/regex_token_iterator/lwg3719.cc | 29 ++++++++++++++
6 files changed, 169 insertions(+), 13 deletions(-)
create mode 100644 libstdc++-v3/testsuite/27_io/filesystem/iterators/lwg3719.cc
create mode 100644 libstdc++-v3/testsuite/28_regex/iterators/regex_iterator/lwg3719.cc
create mode 100644 libstdc++-v3/testsuite/28_regex/iterators/regex_token_iterator/lwg3719.cc
diff --git a/libstdc++-v3/include/bits/fs_dir.h b/libstdc++-v3/include/bits/fs_dir.h
index ca37952ec17..bec2b7674ef 100644
--- a/libstdc++-v3/include/bits/fs_dir.h
+++ b/libstdc++-v3/include/bits/fs_dir.h
@@ -36,8 +36,9 @@
# include <bits/unique_ptr.h>
# include <bits/shared_ptr.h>
-#if __cplusplus > 201703L
+#if __cplusplus >= 202002L
# include <compare> // std::strong_ordering
+# include <bits/iterator_concepts.h> // std::default_sentinel_t
#endif
namespace std _GLIBCXX_VISIBILITY(default)
@@ -420,9 +421,6 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
return __pr;
}
- private:
- directory_iterator(const path&, directory_options, error_code*);
-
friend bool
operator==(const directory_iterator& __lhs,
const directory_iterator& __rhs) noexcept
@@ -431,10 +429,22 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
&& !__lhs._M_dir.owner_before(__rhs._M_dir);
}
+#if __cplusplus >= 202002L
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 3719. Directory iterators should be usable with default sentinel
+ bool operator==(default_sentinel_t) const noexcept
+ { return !_M_dir; }
+#endif
+
+#if __cpp_impl_three_way_comparison < 201907L
friend bool
operator!=(const directory_iterator& __lhs,
const directory_iterator& __rhs) noexcept
{ return !(__lhs == __rhs); }
+#endif
+
+ private:
+ directory_iterator(const path&, directory_options, error_code*);
friend class recursive_directory_iterator;
@@ -519,9 +529,6 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
void disable_recursion_pending() noexcept;
- private:
- recursive_directory_iterator(const path&, directory_options, error_code*);
-
friend bool
operator==(const recursive_directory_iterator& __lhs,
const recursive_directory_iterator& __rhs) noexcept
@@ -530,10 +537,22 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
&& !__lhs._M_dirs.owner_before(__rhs._M_dirs);
}
+#if __cplusplus >= 202002L
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 3719. Directory iterators should be usable with default sentinel
+ bool operator==(default_sentinel_t) const noexcept
+ { return !_M_dirs; }
+#endif
+
+#if __cpp_impl_three_way_comparison < 201907L
friend bool
operator!=(const recursive_directory_iterator& __lhs,
const recursive_directory_iterator& __rhs) noexcept
{ return !(__lhs == __rhs); }
+#endif
+
+ private:
+ recursive_directory_iterator(const path&, directory_options, error_code*);
struct _Dir_stack;
std::__shared_ptr<_Dir_stack> _M_dirs;
diff --git a/libstdc++-v3/include/bits/iterator_concepts.h b/libstdc++-v3/include/bits/iterator_concepts.h
index a04c970b03b..cf66c63f395 100644
--- a/libstdc++-v3/include/bits/iterator_concepts.h
+++ b/libstdc++-v3/include/bits/iterator_concepts.h
@@ -32,15 +32,35 @@
#pragma GCC system_header
+#if __cplusplus >= 202002L
#include <concepts>
#include <bits/ptr_traits.h> // to_address
#include <bits/ranges_cmp.h> // identity, ranges::less
-#if __cpp_lib_concepts
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
+ /** A sentinel type that can be used to check for the end of a range.
+ *
+ * For some iterator types the past-the-end sentinel value is independent
+ * of the underlying sequence, and a default sentinel can be used with them.
+ * For example, a `std::counted_iterator` keeps a count of how many elements
+ * remain, and so checking for the past-the-end value only requires checking
+ * if that count has reached zero. A past-the-end `std::istream_iterator` is
+ * equal to the default-constructed value, which can be easily checked.
+ *
+ * Comparing iterators of these types to `std::default_sentinel` is a
+ * convenient way to check if the end has been reached.
+ *
+ * @since C++20
+ */
+ struct default_sentinel_t { };
+
+ /// A default sentinel value.
+ inline constexpr default_sentinel_t default_sentinel{};
+
+#if __cpp_lib_concepts
struct input_iterator_tag;
struct output_iterator_tag;
struct forward_iterator_tag;
@@ -924,9 +944,6 @@ namespace ranges
inline constexpr unreachable_sentinel_t unreachable_sentinel{};
- struct default_sentinel_t { };
- inline constexpr default_sentinel_t default_sentinel{};
-
// This is the namespace for [range.access] CPOs.
namespace ranges::__cust_access
{
@@ -983,7 +1000,8 @@ namespace ranges
} // namespace __detail
+#endif // C++20 library concepts
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
-#endif // C++20 library concepts
+#endif // C++20
#endif // _ITERATOR_CONCEPTS_H
diff --git a/libstdc++-v3/include/bits/regex.h b/libstdc++-v3/include/bits/regex.h
index 24298e35e2c..561c8fc564a 100644
--- a/libstdc++-v3/include/bits/regex.h
+++ b/libstdc++-v3/include/bits/regex.h
@@ -28,6 +28,10 @@
* Do not attempt to use it directly. @headername{regex}
*/
+#if __cplusplus >= 202002L
+# include <bits/iterator_concepts.h> // std::default_sentinel_t
+#endif
+
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
@@ -2760,12 +2764,21 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
bool
operator==(const regex_iterator&) const noexcept;
+#if __cplusplus >= 202002L
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 3719. Directory iterators should be usable with default sentinel
+ bool operator==(default_sentinel_t) const noexcept
+ { return _M_pregex == nullptr; }
+#endif
+
+#if __cpp_impl_three_way_comparison < 201907L
/**
* @brief Tests the inequivalence of two regex iterators.
*/
bool
operator!=(const regex_iterator& __rhs) const noexcept
{ return !(*this == __rhs); }
+#endif
/**
* @brief Dereferences a %regex_iterator.
@@ -2968,12 +2981,21 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
bool
operator==(const regex_token_iterator& __rhs) const;
+#if __cplusplus >= 202002L
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 3719. Directory iterators should be usable with default sentinel
+ bool operator==(default_sentinel_t) const noexcept
+ { return _M_end_of_seq(); }
+#endif
+
+#if __cpp_impl_three_way_comparison < 201907L
/**
* @brief Compares a %regex_token_iterator to another for inequality.
*/
bool
operator!=(const regex_token_iterator& __rhs) const
{ return !(*this == __rhs); }
+#endif
/**
* @brief Dereferences a %regex_token_iterator.
@@ -3022,7 +3044,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
}
constexpr bool
- _M_end_of_seq() const
+ _M_end_of_seq() const noexcept
{ return _M_result == nullptr; }
// [28.12.2.2.4]
diff --git a/libstdc++-v3/testsuite/27_io/filesystem/iterators/lwg3719.cc b/libstdc++-v3/testsuite/27_io/filesystem/iterators/lwg3719.cc
new file mode 100644
index 00000000000..c19cddc74f9
--- /dev/null
+++ b/libstdc++-v3/testsuite/27_io/filesystem/iterators/lwg3719.cc
@@ -0,0 +1,39 @@
+// { dg-options "-std=gnu++20" }
+// { dg-do run { target c++20 } }
+// { dg-require-filesystem-ts "" }
+
+#include <filesystem>
+#include <iterator>
+#include <testsuite_hooks.h>
+
+// LWG 3719. Directory iterators should be usable with default sentinel
+
+void
+test_dir_iter()
+{
+ std::filesystem::directory_iterator d0;
+ VERIFY( d0 == std::default_sentinel );
+ std::filesystem::directory_iterator d1(".");
+ VERIFY( d1 != std::default_sentinel );
+
+ static_assert( noexcept(d0 == std::default_sentinel) );
+ static_assert( noexcept(d0 != std::default_sentinel) );
+}
+
+void
+test_recursive_dir_iter()
+{
+ std::filesystem::recursive_directory_iterator d0;
+ VERIFY( d0 == std::default_sentinel );
+ std::filesystem::recursive_directory_iterator d1(".");
+ VERIFY( d1 != std::default_sentinel );
+
+ static_assert( noexcept(d0 == std::default_sentinel) );
+ static_assert( noexcept(d0 != std::default_sentinel) );
+}
+
+int main()
+{
+ test_dir_iter();
+ test_recursive_dir_iter();
+}
diff --git a/libstdc++-v3/testsuite/28_regex/iterators/regex_iterator/lwg3719.cc b/libstdc++-v3/testsuite/28_regex/iterators/regex_iterator/lwg3719.cc
new file mode 100644
index 00000000000..e8c8f79364a
--- /dev/null
+++ b/libstdc++-v3/testsuite/28_regex/iterators/regex_iterator/lwg3719.cc
@@ -0,0 +1,29 @@
+// { dg-options "-std=gnu++20" }
+// { dg-do run { target c++20 } }
+
+#include <regex>
+#include <iterator>
+#include <testsuite_hooks.h>
+
+// LWG 3719. Directory iterators should be usable with default sentinel
+
+void
+test_iter()
+{
+ std::sregex_token_iterator r0;
+ VERIFY( r0 == std::default_sentinel );
+ std::string haystack = "a needle in a haystack";
+ std::regex needle("needle");
+ std::sregex_iterator r1(haystack.begin(), haystack.end(), needle);
+ VERIFY( r1 != std::default_sentinel );
+ ++r1;
+ VERIFY( r1 == std::default_sentinel );
+
+ static_assert( noexcept(r0 == std::default_sentinel) ); // GCC extension
+ static_assert( noexcept(r0 != std::default_sentinel) ); // GCC extension
+}
+
+int main()
+{
+ test_iter();
+}
diff --git a/libstdc++-v3/testsuite/28_regex/iterators/regex_token_iterator/lwg3719.cc b/libstdc++-v3/testsuite/28_regex/iterators/regex_token_iterator/lwg3719.cc
new file mode 100644
index 00000000000..5c36acead74
--- /dev/null
+++ b/libstdc++-v3/testsuite/28_regex/iterators/regex_token_iterator/lwg3719.cc
@@ -0,0 +1,29 @@
+// { dg-options "-std=gnu++20" }
+// { dg-do run { target c++20 } }
+
+#include <regex>
+#include <iterator>
+#include <testsuite_hooks.h>
+
+// LWG 3719. Directory iterators should be usable with default sentinel
+
+void
+test_iter()
+{
+ std::sregex_iterator r0;
+ VERIFY( r0 == std::default_sentinel );
+ std::string haystack = "a needle in a haystack";
+ std::regex needle("needle");
+ std::sregex_iterator r1(haystack.begin(), haystack.end(), needle);
+ VERIFY( r1 != std::default_sentinel );
+ ++r1;
+ VERIFY( r1 == std::default_sentinel );
+
+ static_assert( noexcept(r0 == std::default_sentinel) ); // GCC extension
+ static_assert( noexcept(r0 != std::default_sentinel) ); // GCC extension
+}
+
+int main()
+{
+ test_iter();
+}
--
2.37.1
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2022-08-04 18:38 [committed] libstdc++: Add comparisons to std::default_sentinel_t (LWG 3719) Jonathan Wakely
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