Implement LWG-3719: Directory iterators should be usable with default…

… sentinel (#2902) Co-authored-by: Stephan T. Lavavej <[email protected]>
microsoft · Jul 28, 2022 · 3da2dfd · 3da2dfd
1 parent b491ec6
commit 3da2dfd
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diff --git a/stl/inc/filesystem b/stl/inc/filesystem
@@ -2717,6 +2717,12 @@ namespace filesystem {
         }
 #endif // !_HAS_CXX20
 
+#ifdef __cpp_lib_concepts
+        _NODISCARD bool operator==(default_sentinel_t) const noexcept {
+            return !_Impl;
+        }
+#endif // __cpp_lib_concepts
+
         _Directory_entry_proxy operator++(int) {
             _Directory_entry_proxy _Proxy(**this);
             ++*this;
@@ -2967,6 +2973,12 @@ namespace filesystem {
         }
 #endif // !_HAS_CXX20
 
+#ifdef __cpp_lib_concepts
+        _NODISCARD bool operator==(default_sentinel_t) const noexcept {
+            return !_Impl;
+        }
+#endif // __cpp_lib_concepts
+
         _Directory_entry_proxy operator++(int) {
             _Directory_entry_proxy _Proxy(**this);
             ++*this;

diff --git a/stl/inc/regex b/stl/inc/regex
@@ -2417,6 +2417,12 @@ public:
     }
 #endif // !_HAS_CXX20
 
+#ifdef __cpp_lib_concepts
+    _NODISCARD bool operator==(default_sentinel_t) const {
+        return !_MyRe;
+    }
+#endif // __cpp_lib_concepts
+
     _NODISCARD const value_type& operator*() const {
 #if _ITERATOR_DEBUG_LEVEL != 0
         _STL_VERIFY(_MyRe, "regex_iterator not dereferenceable");
@@ -2601,6 +2607,12 @@ public:
     }
 #endif // !_HAS_CXX20
 
+#ifdef __cpp_lib_concepts
+    _NODISCARD bool operator==(default_sentinel_t) const {
+        return !_Res;
+    }
+#endif // __cpp_lib_concepts
+
     _NODISCARD const value_type& operator*() const {
 #if _ITERATOR_DEBUG_LEVEL != 0
         _STL_VERIFY(_Res, "regex_token_iterator not dereferenceable");

diff --git a/tests/std/tests/P0896R4_stream_iterators/test.cpp b/tests/std/tests/P0896R4_stream_iterators/test.cpp
@@ -2,15 +2,21 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 // Covers Ranges changes to istream_iterator, ostream_iterator, istreambuf_iterator, and ostreambuf_iterator
+// and LWG-3719 changes for directory_iterator, recursive_directory_iterator, regex_iterator, and regex_token_iterator
 
 #include <cassert>
 #include <cstddef>
 #include <iostream>
 #include <iterator>
+#include <regex>
 #include <string>
 #include <type_traits>
 #include <utility>
 
+#if _HAS_CXX17
+#include <filesystem>
+#endif // _HAS_CXX17
+
 using namespace std;
 
 #define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
@@ -101,6 +107,136 @@ void test_ostreambuf_iterator(basic_ostream<CharT, Traits>& os) {
 #endif // __cpp_lib_concepts
 }
 
+template <class C, enable_if_t<is_same_v<C, char>, int> = 0>
+constexpr auto statically_widen_impl(const char* narrow_str, const wchar_t*) noexcept {
+    return narrow_str;
+}
+
+template <class C, enable_if_t<!is_same_v<C, char>, int> = 0>
+constexpr auto statically_widen_impl(const char*, const wchar_t* wide_str) noexcept {
+    return wide_str;
+}
+
+#define STATICALLY_WIDEN(C, S) statically_widen_impl<C>(S, L##S)
+
+template <class Sequence>
+void test_regex_iterator(const Sequence& seq) {
+    (void) seq;
+#ifdef __cpp_lib_concepts
+    using SequenceIter = decltype(cbegin(seq));
+    using CharT        = remove_cv_t<iter_value_t<SequenceIter>>;
+    using I            = regex_iterator<SequenceIter>;
+
+    const I end_it{};
+    assert(end_it == default_sentinel);
+    assert(default_sentinel == end_it);
+    assert(!(end_it != default_sentinel));
+    assert(!(default_sentinel != end_it));
+
+    basic_regex<CharT> re(STATICALLY_WIDEN(CharT, "[a-z]"));
+    I begin_it{cbegin(seq), cend(seq), re};
+    assert(begin_it != default_sentinel);
+    assert(default_sentinel != begin_it);
+    assert(!(begin_it == default_sentinel));
+    assert(!(default_sentinel == begin_it));
+
+    ranges::advance(begin_it, end_it);
+    assert(begin_it == default_sentinel);
+    assert(default_sentinel == begin_it);
+    assert(!(begin_it != default_sentinel));
+    assert(!(default_sentinel != begin_it));
+#endif // __cpp_lib_concepts
+}
+
+template <class Sequence>
+void test_regex_token_iterator(const Sequence& seq) {
+    (void) seq;
+#ifdef __cpp_lib_concepts
+    using SequenceIter = decltype(cbegin(seq));
+    using CharT        = remove_cv_t<iter_value_t<SequenceIter>>;
+    using I            = regex_token_iterator<SequenceIter>;
+
+    const I end_it{};
+    assert(end_it == default_sentinel);
+    assert(default_sentinel == end_it);
+    assert(!(end_it != default_sentinel));
+    assert(!(default_sentinel != end_it));
+
+    basic_regex<CharT> re(STATICALLY_WIDEN(CharT, "[a-z]"));
+    I begin_it{cbegin(seq), cend(seq), re};
+    assert(begin_it != default_sentinel);
+    assert(default_sentinel != begin_it);
+    assert(!(begin_it == default_sentinel));
+    assert(!(default_sentinel == begin_it));
+
+    ranges::advance(begin_it, end_it);
+    assert(begin_it == default_sentinel);
+    assert(default_sentinel == begin_it);
+    assert(!(begin_it != default_sentinel));
+    assert(!(default_sentinel != begin_it));
+#endif // __cpp_lib_concepts
+}
+
+#if _HAS_CXX17
+void test_directory_iterator() {
+#ifdef __cpp_lib_concepts
+    using I = filesystem::directory_iterator;
+
+    const I end_it{};
+    STATIC_ASSERT(noexcept(end_it == default_sentinel));
+    STATIC_ASSERT(noexcept(end_it != default_sentinel));
+    STATIC_ASSERT(noexcept(default_sentinel == end_it));
+    STATIC_ASSERT(noexcept(default_sentinel != end_it));
+
+    assert(end_it == default_sentinel);
+    assert(default_sentinel == end_it);
+    assert(!(end_it != default_sentinel));
+    assert(!(default_sentinel != end_it));
+
+    I begin_it{filesystem::path{L"."}};
+    assert(begin_it != default_sentinel);
+    assert(default_sentinel != begin_it);
+    assert(!(begin_it == default_sentinel));
+    assert(!(default_sentinel == begin_it));
+
+    ranges::advance(begin_it, end_it);
+    assert(begin_it == default_sentinel);
+    assert(default_sentinel == begin_it);
+    assert(!(begin_it != default_sentinel));
+    assert(!(default_sentinel != begin_it));
+#endif // __cpp_lib_concepts
+}
+
+void test_recursive_directory_iterator() {
+#ifdef __cpp_lib_concepts
+    using I = filesystem::recursive_directory_iterator;
+
+    const I end_it{};
+    STATIC_ASSERT(noexcept(end_it == default_sentinel));
+    STATIC_ASSERT(noexcept(end_it != default_sentinel));
+    STATIC_ASSERT(noexcept(default_sentinel == end_it));
+    STATIC_ASSERT(noexcept(default_sentinel != end_it));
+
+    assert(end_it == default_sentinel);
+    assert(default_sentinel == end_it);
+    assert(!(end_it != default_sentinel));
+    assert(!(default_sentinel != end_it));
+
+    I begin_it{filesystem::path{L"."}};
+    assert(begin_it != default_sentinel);
+    assert(default_sentinel != begin_it);
+    assert(!(begin_it == default_sentinel));
+    assert(!(default_sentinel == begin_it));
+
+    ranges::advance(begin_it, end_it);
+    assert(begin_it == default_sentinel);
+    assert(default_sentinel == begin_it);
+    assert(!(begin_it != default_sentinel));
+    assert(!(default_sentinel != begin_it));
+#endif // __cpp_lib_concepts
+}
+#endif // _HAS_CXX17
+
 int main() {
     test_istream_iterator<int>();
     test_istream_iterator<string>();
@@ -117,4 +253,19 @@ int main() {
 
     test_ostreambuf_iterator(cout);
     test_ostreambuf_iterator(wcout);
+
+    test_regex_iterator("hello world");
+    test_regex_iterator(L"hello world");
+    test_regex_iterator(string{"hello world"});
+    test_regex_iterator(wstring{L"hello world"});
+
+    test_regex_token_iterator("hello world");
+    test_regex_token_iterator(L"hello world");
+    test_regex_token_iterator(string{"hello world"});
+    test_regex_token_iterator(wstring{L"hello world"});
+
+#if _HAS_CXX17
+    test_directory_iterator();
+    test_recursive_directory_iterator();
+#endif // _HAS_CXX17
 }