[libc++][format] Add basic_format_parse_context.
Implements parts of:
- P0645 Text Formatting
Depends on D92214
Reland with changes:
The format header will only be compiled if the compiler used has support
for concepts. This should fix the issues with the initial version.
Differential Revision: https://reviews.llvm.org/D93166
GitOrigin-RevId: 38ddeade65c50343a7f6a0daec57139b07ec7807
diff --git a/include/__config b/include/__config
index cd1f4da..102dee1 100644
--- a/include/__config
+++ b/include/__config
@@ -536,6 +536,10 @@
#define _LIBCPP_HAS_NO_VARIABLE_TEMPLATES
#endif
+#if !defined(__cpp_concepts) || __cpp_concepts < 201907L
+#define _LIBCPP_HAS_NO_CONCEPTS
+#endif
+
#if !defined(_LIBCPP_HAS_NO_ASAN) && !defined(__SANITIZE_ADDRESS__)
#define _LIBCPP_HAS_NO_ASAN
#endif
diff --git a/include/format b/include/format
index 833423a..9e41120 100644
--- a/include/format
+++ b/include/format
@@ -19,14 +19,51 @@
explicit format_error(const string& what_arg);
explicit format_error(const char* what_arg);
};
+
+ // [format.parse.ctx], class template basic_format_parse_context
+ template<class charT>
+ class basic_format_parse_context {
+ public:
+ using char_type = charT;
+ using const_iterator = typename basic_string_view<charT>::const_iterator;
+ using iterator = const_iterator;
+
+ private:
+ iterator begin_; // exposition only
+ iterator end_; // exposition only
+ enum indexing { unknown, manual, automatic }; // exposition only
+ indexing indexing_; // exposition only
+ size_t next_arg_id_; // exposition only
+ size_t num_args_; // exposition only
+
+ public:
+ constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
+ size_t num_args = 0) noexcept;
+ basic_format_parse_context(const basic_format_parse_context&) = delete;
+ basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
+
+ constexpr const_iterator begin() const noexcept;
+ constexpr const_iterator end() const noexcept;
+ constexpr void advance_to(const_iterator it);
+
+ constexpr size_t next_arg_id();
+ constexpr void check_arg_id(size_t id);
+ };
+ using format_parse_context = basic_format_parse_context<char>;
+ using wformat_parse_context = basic_format_parse_context<wchar_t>;
}
*/
#include <__config>
#include <stdexcept>
+#include <string_view>
#include <version>
+#ifdef _LIBCPP_NO_EXCEPTIONS
+#include <cstdlib>
+#endif
+
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
@@ -38,6 +75,12 @@
#if _LIBCPP_STD_VER > 17
+// TODO FMT Remove this once we require compilers with proper C++20 support.
+// If the compiler has no concepts support, the format header will be disabled.
+// Without concepts support enable_if needs to be used and that too much effort
+// to support compilers with partial C++20 support.
+#ifndef _LIBCPP_HAS_NO_CONCEPTS
+
class _LIBCPP_EXCEPTION_ABI format_error : public runtime_error {
public:
_LIBCPP_INLINE_VISIBILITY explicit format_error(const string& __s)
@@ -47,6 +90,89 @@
virtual ~format_error() noexcept;
};
+_LIBCPP_NORETURN inline _LIBCPP_INLINE_VISIBILITY void
+__throw_format_error(const char* __s) {
+#ifndef _LIBCPP_NO_EXCEPTIONS
+ throw format_error(__s);
+#else
+ (void)__s;
+ _VSTD::abort();
+#endif
+}
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS basic_format_parse_context {
+public:
+ using char_type = _CharT;
+ using const_iterator =
+ typename _VSTD::basic_string_view<_CharT>::const_iterator;
+ using iterator = const_iterator;
+
+public:
+ _LIBCPP_INLINE_VISIBILITY
+ constexpr explicit basic_format_parse_context(
+ _VSTD::basic_string_view<_CharT> __fmt, size_t __num_args = 0) noexcept
+ : __begin_(__fmt.begin()),
+ __end_(__fmt.end()),
+ __indexing_(__unknown),
+ __next_arg_id_(0),
+ __num_args_(__num_args) {}
+
+ basic_format_parse_context(const basic_format_parse_context&) = delete;
+ basic_format_parse_context&
+ operator=(const basic_format_parse_context&) = delete;
+
+ _LIBCPP_INLINE_VISIBILITY constexpr const_iterator begin() const noexcept {
+ return __begin_;
+ }
+ _LIBCPP_INLINE_VISIBILITY constexpr const_iterator end() const noexcept {
+ return __end_;
+ }
+ _LIBCPP_INLINE_VISIBILITY constexpr void advance_to(const_iterator __it) {
+ __begin_ = __it;
+ }
+
+ _LIBCPP_INLINE_VISIBILITY constexpr size_t next_arg_id() {
+ if (__indexing_ == __manual)
+ __throw_format_error("Using automatic argument numbering in manual "
+ "argument numbering mode");
+
+ if (__indexing_ == __unknown)
+ __indexing_ = __automatic;
+ return __next_arg_id_++;
+ }
+ _LIBCPP_INLINE_VISIBILITY constexpr void check_arg_id(size_t __id) {
+ if (__indexing_ == __automatic)
+ __throw_format_error("Using manual argument numbering in automatic "
+ "argument numbering mode");
+
+ if (__indexing_ == __unknown)
+ __indexing_ = __manual;
+
+ // Throws an exception to make the expression a non core constant
+ // expression as required by:
+ // [format.parse.ctx]/11
+ // Remarks: Call expressions where id >= num_args_ are not core constant
+ // expressions ([expr.const]).
+ // Note: the Throws clause [format.parse.ctx]/10 doesn't specify the
+ // behavior when id >= num_args_.
+ if (_VSTD::is_constant_evaluated() && __id >= __num_args_)
+ __throw_format_error("Argument index outside the valid range");
+ }
+
+private:
+ iterator __begin_;
+ iterator __end_;
+ enum _Indexing { __unknown, __manual, __automatic };
+ _Indexing __indexing_;
+ size_t __next_arg_id_;
+ size_t __num_args_;
+};
+
+using format_parse_context = basic_format_parse_context<char>;
+using wformat_parse_context = basic_format_parse_context<wchar_t>;
+
+#endif //_LIBCPP_HAS_NO_CONCEPTS
#endif //_LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
diff --git a/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp b/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp
new file mode 100644
index 0000000..c91d1b8
--- /dev/null
+++ b/test/std/utilities/format/format.formatter/format.parse.ctx/advance_to.pass.cpp
@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+
+// <format>
+
+// constexpr void advance_to(const_iterator it);
+
+#include <format>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class CharT>
+constexpr void test(const CharT* fmt) {
+ {
+ std::basic_format_parse_context<CharT> context(fmt);
+
+ context.advance_to(context.begin() + 1);
+ assert(context.begin() == &fmt[1]);
+
+ context.advance_to(context.begin() + 1);
+ assert(context.begin() == &fmt[2]);
+
+ context.advance_to(context.begin() + 1);
+ assert(context.begin() == context.end());
+ }
+ {
+ std::basic_string_view view{fmt};
+ std::basic_format_parse_context context(view);
+
+ context.advance_to(context.begin() + 1);
+ assert(context.begin() == view.begin() + 1);
+
+ context.advance_to(context.begin() + 1);
+ assert(context.begin() == view.begin() + 2);
+
+ context.advance_to(context.begin() + 1);
+ assert(context.begin() == context.end());
+ }
+}
+
+constexpr bool test() {
+ test("abc");
+ test(L"abc");
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+ test(u8"abc");
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+ test(u"abc");
+ test(U"abc");
+#endif
+
+ return true;
+}
+
+int main(int, char**) {
+ test();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp b/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp
new file mode 100644
index 0000000..b08129b
--- /dev/null
+++ b/test/std/utilities/format/format.formatter/format.parse.ctx/begin.pass.cpp
@@ -0,0 +1,54 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+
+// <format>
+
+// constexpr begin() const noexcept;
+
+#include <format>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class CharT>
+constexpr void test(const CharT* fmt) {
+ {
+ std::basic_format_parse_context<CharT> context(fmt);
+ assert(context.begin() == &fmt[0]);
+ ASSERT_NOEXCEPT(context.begin());
+ }
+ {
+ std::basic_string_view view{fmt};
+ std::basic_format_parse_context context(view);
+ assert(context.begin() == view.begin());
+ ASSERT_NOEXCEPT(context.begin());
+ }
+}
+
+constexpr bool test() {
+ test("abc");
+ test(L"abc");
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+ test(u8"abc");
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+ test(u"abc");
+ test(U"abc");
+#endif
+
+ return true;
+}
+
+int main(int, char**) {
+ test();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp b/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
new file mode 100644
index 0000000..734dc41
--- /dev/null
+++ b/test/std/utilities/format/format.formatter/format.parse.ctx/check_arg_id.pass.cpp
@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: no-exceptions
+
+// This test requires the dylib support introduced in D92214.
+// XFAIL: with_system_cxx_lib=macosx10.15
+// XFAIL: with_system_cxx_lib=macosx10.14
+// XFAIL: with_system_cxx_lib=macosx10.13
+// XFAIL: with_system_cxx_lib=macosx10.12
+// XFAIL: with_system_cxx_lib=macosx10.11
+// XFAIL: with_system_cxx_lib=macosx10.10
+// XFAIL: with_system_cxx_lib=macosx10.9
+
+// <format>
+
+// constexpr void check_arg_id(size_t id);
+
+#include <format>
+#include <cassert>
+
+#include "test_macros.h"
+
+constexpr bool test() {
+ std::format_parse_context context("", 10);
+ for (size_t i = 0; i < 10; ++i)
+ context.check_arg_id(i);
+
+ return true;
+}
+
+void test_exception() {
+ [] {
+ std::format_parse_context context("", 1);
+ context.next_arg_id();
+ try {
+ context.check_arg_id(0);
+ assert(false);
+ } catch (const std::format_error& e) {
+ assert(strcmp(e.what(), "Using manual argument numbering in automatic "
+ "argument numbering mode") == 0);
+ return;
+ }
+ assert(false);
+ }();
+
+ auto test_arg = [](size_t num_args) {
+ std::format_parse_context context("", num_args);
+ // Out of bounds access is valid if !std::is_constant_evaluated()
+ for (size_t i = 0; i <= num_args; ++i)
+ context.check_arg_id(i);
+ };
+ for (size_t i = 0; i < 10; ++i)
+ test_arg(i);
+}
+
+int main(int, char**) {
+ test();
+ test_exception();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp b/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp
new file mode 100644
index 0000000..5a4a046
--- /dev/null
+++ b/test/std/utilities/format/format.formatter/format.parse.ctx/ctor.pass.cpp
@@ -0,0 +1,77 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+
+// <format>
+
+// constexpr explicit
+// basic_format_parse_context(basic_string_view<charT> fmt,
+// size_t num_args = 0) noexcept
+
+#include <format>
+#include <cassert>
+#include <type_traits>
+
+#include "test_macros.h"
+
+template <class CharT>
+constexpr void test(const CharT* fmt) {
+ // Validate the constructor is explicit.
+ static_assert(
+ !std::is_convertible_v<std::basic_string_view<CharT>,
+ std::basic_format_parse_context<CharT> >);
+ static_assert(
+ !std::is_copy_constructible_v<std::basic_format_parse_context<CharT> >);
+ static_assert(
+ !std::is_copy_assignable_v<std::basic_format_parse_context<CharT> >);
+ // The move operations are implicitly deleted due to the
+ // deleted copy operations.
+ static_assert(
+ !std::is_move_constructible_v<std::basic_format_parse_context<CharT> >);
+ static_assert(
+ !std::is_move_assignable_v<std::basic_format_parse_context<CharT> >);
+
+ ASSERT_NOEXCEPT(
+ std::basic_format_parse_context{std::basic_string_view<CharT>{}});
+ ASSERT_NOEXCEPT(
+ std::basic_format_parse_context{std::basic_string_view<CharT>{}, 42});
+
+ {
+ std::basic_format_parse_context<CharT> context(fmt);
+ assert(context.begin() == &fmt[0]);
+ assert(context.end() == &fmt[3]);
+ }
+ {
+ std::basic_string_view view{fmt};
+ std::basic_format_parse_context context(view);
+ assert(context.begin() == view.begin());
+ assert(context.end() == view.end());
+ }
+}
+
+constexpr bool test() {
+ test("abc");
+ test(L"abc");
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+ test(u8"abc");
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+ test(u"abc");
+ test(U"abc");
+#endif
+
+ return true;
+}
+
+int main(int, char**) {
+ test();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp b/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp
new file mode 100644
index 0000000..323939a
--- /dev/null
+++ b/test/std/utilities/format/format.formatter/format.parse.ctx/end.pass.cpp
@@ -0,0 +1,54 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+
+// <format>
+
+// constexpr end() const noexcept;
+
+#include <format>
+#include <cassert>
+
+#include "test_macros.h"
+
+template <class CharT>
+constexpr void test(const CharT* fmt) {
+ {
+ std::basic_format_parse_context<CharT> context(fmt);
+ assert(context.end() == &fmt[3]);
+ ASSERT_NOEXCEPT(context.end());
+ }
+ {
+ std::basic_string_view view{fmt};
+ std::basic_format_parse_context context(view);
+ assert(context.end() == view.end());
+ ASSERT_NOEXCEPT(context.end());
+ }
+}
+
+constexpr bool test() {
+ test("abc");
+ test(L"abc");
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+ test(u8"abc");
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+ test(u"abc");
+ test(U"abc");
+#endif
+
+ return true;
+}
+
+int main(int, char**) {
+ test();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp b/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
new file mode 100644
index 0000000..77197ad
--- /dev/null
+++ b/test/std/utilities/format/format.formatter/format.parse.ctx/next_arg_id.pass.cpp
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: no-exceptions
+
+// This test requires the dylib support introduced in D92214.
+// XFAIL: with_system_cxx_lib=macosx10.15
+// XFAIL: with_system_cxx_lib=macosx10.14
+// XFAIL: with_system_cxx_lib=macosx10.13
+// XFAIL: with_system_cxx_lib=macosx10.12
+// XFAIL: with_system_cxx_lib=macosx10.11
+// XFAIL: with_system_cxx_lib=macosx10.10
+// XFAIL: with_system_cxx_lib=macosx10.9
+
+// <format>
+
+// constexpr size_t next_arg_id();
+
+#include <format>
+#include <cassert>
+
+#include "test_macros.h"
+
+constexpr bool test() {
+ std::format_parse_context context("");
+ for (size_t i = 0; i < 10; ++i)
+ assert(i == context.next_arg_id());
+
+ return true;
+}
+
+void test_exception() {
+ std::format_parse_context context("", 1);
+ context.check_arg_id(0);
+
+ try {
+ context.next_arg_id();
+ assert(false);
+ } catch (const std::format_error& e) {
+ assert(strcmp(e.what(), "Using automatic argument numbering in manual "
+ "argument numbering mode") == 0);
+ return;
+ }
+ assert(false);
+}
+
+int main(int, char**) {
+ test();
+ test_exception();
+ static_assert(test());
+
+ return 0;
+}
diff --git a/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp b/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp
new file mode 100644
index 0000000..c9301c5
--- /dev/null
+++ b/test/std/utilities/format/format.formatter/format.parse.ctx/types.compile.pass.cpp
@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+// UNSUPPORTED: libcpp-no-concepts
+
+// <format>
+
+// Class typedefs:
+// template<class charT>
+// class basic_format_parse_context {
+// public:
+// using char_type = charT;
+// using const_iterator = typename basic_string_view<charT>::const_iterator;
+// using iterator = const_iterator;
+// }
+//
+// Namespace std typedefs:
+// using format_parse_context = basic_format_parse_context<char>;
+// using wformat_parse_context = basic_format_parse_context<wchar_t>;
+
+#include <format>
+#include <type_traits>
+
+#include "test_macros.h"
+
+template <class CharT>
+constexpr void test() {
+ static_assert(
+ std::is_same_v<typename std::basic_format_parse_context<CharT>::char_type,
+ CharT>);
+ static_assert(std::is_same_v<
+ typename std::basic_format_parse_context<CharT>::const_iterator,
+ typename std::basic_string_view<CharT>::const_iterator>);
+ static_assert(
+ std::is_same_v<
+ typename std::basic_format_parse_context<CharT>::iterator,
+ typename std::basic_format_parse_context<CharT>::const_iterator>);
+}
+
+constexpr void test() {
+ test<char>();
+ test<wchar_t>();
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+ test<char8_t>();
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+ test<char16_t>();
+ test<char32_t>();
+#endif
+}
+
+static_assert(std::is_same_v<std::format_parse_context,
+ std::basic_format_parse_context<char> >);
+static_assert(std::is_same_v<std::wformat_parse_context,
+ std::basic_format_parse_context<wchar_t> >);
+
+// Required for MSVC internal test runner compatibility.
+int main(int, char**) { return 0; }
