[libc++] Adds a make_string test helper function.

[Mordante]

Summary

These function makes it easier to write generic unit tests for the
format header. It solves the issue where it's not possible to use

`templated_prefix"foo"`

where templated_prefix resolves to: nothing, L, u8, u,
or U. The templated_prefix would be more faster during execution.

[Mordante]

Disable unit test when localization is disabled.

[mclow.lists]

How about something more like:

make_string<char>(
                  " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
                          "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~")
      ==          " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
                          "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~");

instead?

libcxx/test/support/test.support/make_string_header.pass.cpp

24

the indentation here makes it hard to see that the literals are supposed to be identical.

[Mordante]

Thanks for the review!

libcxx/test/support/test.support/make_string_header.pass.cpp

24

I'll have a look at manually formatting the code.

[Mordante]

Improve the formatting as requested by @mclow.lists.
Disabled the automatic formatting to make sure the formatting won't be updated
automatically.

[mclow.lists]

libcxx/test/support/test.support/make_string_header.pass.cpp

24

Much easier to read; thanks.

[curdeius]

LGTM. Just 2 nits.
Have you looked at what @mstorsjo did in his series of patches for porting filesystem to Windows? I have a vague idea that there were some converting utilities similar to this one.

libcxx/test/support/make_string.h

24

Nit: "there are no" instead of "are no".

31

Nit: convertor? Why not converter?

[Mordante]

In D93414#2522792, @curdeius wrote:

LGTM. Just 2 nits.
Have you looked at what @mstorsjo did in his series of patches for porting filesystem to Windows? I have a vague idea that there were some converting utilities similar to this one.

Thanks for the review. I've didn't have a close look at @mstorsjo's changes. @mstorsjo do you have code in review with similar functionality?

libcxx/test/support/make_string.h

24

Will fix.

31

As far as I know they are synonyms, but I'm no native speaker. But it seems converter is more common, so will adjust the code.

[Mordante]

Addresses review comments.
Rebased.

[mstorsjo]

In D93414#2525656, @Mordante wrote:

In D93414#2522792, @curdeius wrote:

LGTM. Just 2 nits.
Have you looked at what @mstorsjo did in his series of patches for porting filesystem to Windows? I have a vague idea that there were some converting utilities similar to this one.

Thanks for the review. I've didn't have a close look at @mstorsjo's changes. @mstorsjo do you have code in review with similar functionality?

Not entirely sure what that'd refer to - maybe there's some similarity to https://reviews.llvm.org/D90222#change-3lQgyuTryhdf - with the MultiStringType class that I modified for similar cases (with some char types being optionally available).

[ldionne]

libcxx/test/support/make_string.h

26

That is not going to work when the test suite is run against non-libc++. Can we replace by something that doesn't depend on libc++?

[Mordante]

In D93414#2526120, @mstorsjo wrote:

Not entirely sure what that'd refer to - maybe there's some similarity to https://reviews.llvm.org/D90222#change-3lQgyuTryhdf - with the MultiStringType class that I modified for similar cases (with some char types being optionally available).

Yes it seems MultiStringType does something similar. I've to see how well it fits in my unit tests. Thanks for the hint!

libcxx/test/support/make_string.h

26

I had a look and test/std/depr/depr.c.headers/stdio_h.pass.cpp uses

#if defined(__GNUC__) || defined(__clang__)
#pragma GCC diagnostic ignored "-Wformat-zero-length"
#pragma GCC diagnostic ignored "-Wdeprecated-declarations" // for tmpnam
#endif

But I'll first have a look at MultiStringType. If that suits my needs this revision seems obsolete.

[Mordante]

Changed the implementation to use the macros from
libcxx/test/support/filesystem_test_helper.h.
The macros are moved and the original header now depends on the new helper.

[Mordante]

libcxx/test/support/make_string.h

26

That is not going to work when the test suite is run against non-libc++. Can we replace by something that doesn't depend on libc++?

With the changed implementation this code is entirely removed.

[ldionne]

Thanks!

libcxx/test/support/make_string.h

+//===----------------------------------------------------------------------===//
+//
+// 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 SUPPORT_TEST_MAKE_STRING_H
+#define SUPPORT_TEST_MAKE_STRING_H
+
+#include "test_macros.h"
+
+#if TEST_STD_VER < 11
+#error This header requires C++11 or greater
+#endif
+
+#include <string>
+#include <locale>
+#include <codecvt>
+
+// Some of these std::codecvt specializations have been deprecated. At the
+// moment are no replacements in the Standard so use the deprecated facilities.
+_LIBCPP_SUPPRESS_DEPRECATED_PUSH
+// Helper function to convert a const char* string to a basic_string<CharT>.
+// This helper is used in unit tests to make them generic. The input should be
+// valid ASCII which means the input is also valid UTF-8.
+template <class CharT>
+std::basic_string<CharT> make_string(const char* str) {
+  struct convertor_type : public std::codecvt<CharT, char, std::mbstate_t> {
+    using std::codecvt<CharT, char, std::mbstate_t>::codecvt;
+    ~convertor_type() = default;
+  };
+
+  std::wstring_convert<convertor_type, CharT> convertor;
+  return convertor.from_bytes(str);
+}
+_LIBCPP_SUPPRESS_DEPRECATED_POP
+
+template <>
+std::basic_string<char> make_string(const char* str) {
+  return std::basic_string<char>(str);
+}
+
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+template <>
+std::basic_string<char8_t> make_string(const char* str) {
+  std::basic_string<char8_t> result;
+  auto out = std::back_inserter(result);
+  while (*str)
+    out = *str++;
+
+  return result;
+}
+#endif
+
+#endif

libcxx/test/support/test.support/make_string_header.pass.cpp

+//===----------------------------------------------------------------------===//
+// 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
+
+// "support/make_string.h"
+
+#include "make_string.h"
+#include <cassert>
+
+#include "test_macros.h"
+
+int main(int, char**) {
+  assert(
+      make_string<char>(" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+                        "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~") ==
+      " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+      "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~");
+
+  assert(make_string<wchar_t>(
+             " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+             "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~") ==
+         L" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+         "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~");
+#ifndef _LIBCPP_NO_HAS_CHAR8_T
+  assert(make_string<char8_t>(
+             " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+             "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~") ==
+         u8" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+         "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~");
+#endif
+#ifndef _LIBCPP_HAS_NO_UNICODE_CHARS
+  assert(make_string<char16_t>(
+             " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+             "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~") ==
+         u" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+         "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~");
+
+  assert(make_string<char32_t>(
+             " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+             "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~") ==
+         U" !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMN"
+         "OPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~");
+#endif
+
+  return 0;
+}