[gcc r12-8590] libstdc++: Fix experimental::filesystem::status on Windows [PR88881]

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:f3ff78e3db0fc18127dac4fe3eaf113d0c5ddd01

commit r12-8590-gf3ff78e3db0fc18127dac4fe3eaf113d0c5ddd01
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Jun 28 15:56:30 2022 +0100

    libstdc++: Fix experimental::filesystem::status on Windows [PR88881]
    
    Although the Filesystem TS isn't properly supported on Windows (unlike
    the C++17 Filesystem lib), most tests do pass. Two of the failures are
    due to PR 88881 which was only fixed for std::filesystem not the TS.
    This applies the fix to the TS implementation too.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/88881
            * src/filesystem/ops.cc (has_trailing_slash): New helper
            function.
            (fs::status): Strip trailing slashes.
            (fs::symlink_status): Likewise.
            * testsuite/experimental/filesystem/operations/temp_directory_path.cc:
            Clean the environment before each test and use TMP instead of
            TMPDIR so the test passes on Windows.
    
    (cherry picked from commit 6c96b14a19a9e6c365eacc59868a866b99f9786d)

Diff:
---
 libstdc++-v3/src/filesystem/ops.cc                 | 56 +++++++++++++++++++++-
 .../filesystem/operations/temp_directory_path.cc   |  6 ++-
 2 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/libstdc++-v3/src/filesystem/ops.cc b/libstdc++-v3/src/filesystem/ops.cc
index 98ddff5a66e..896a4918ace 100644
--- a/libstdc++-v3/src/filesystem/ops.cc
+++ b/libstdc++-v3/src/filesystem/ops.cc
@@ -1176,13 +1176,43 @@ fs::space(const path& p, error_code& ec) noexcept
   return info;
 }
 
+#if _GLIBCXX_FILESYSTEM_IS_WINDOWS
+static bool has_trailing_slash(const fs::path& p)
+{
+  wchar_t c = p.native().back();
+  return c == '/' || c == L'\\';
+}
+#endif
+
 #ifdef _GLIBCXX_HAVE_SYS_STAT_H
 fs::file_status
 fs::status(const fs::path& p, error_code& ec) noexcept
 {
   file_status status;
+
+  auto str = p.c_str();
+
+#if _GLIBCXX_FILESYSTEM_IS_WINDOWS
+  // stat() fails if there's a trailing slash (PR 88881)
+  path p2;
+  if (p.has_relative_path() && has_trailing_slash(p))
+    {
+      __try
+	{
+	  p2 = p.parent_path();
+	  str = p2.c_str();
+	}
+      __catch(const bad_alloc&)
+	{
+	  ec = std::make_error_code(std::errc::not_enough_memory);
+	  return status;
+	}
+      str = p2.c_str();
+    }
+#endif
+
   stat_type st;
-  if (posix::stat(p.c_str(), &st))
+  if (posix::stat(str, &st))
     {
       int err = errno;
       ec.assign(err, std::generic_category());
@@ -1205,8 +1235,30 @@ fs::file_status
 fs::symlink_status(const fs::path& p, std::error_code& ec) noexcept
 {
   file_status status;
+
+  auto str = p.c_str();
+
+#if _GLIBCXX_FILESYSTEM_IS_WINDOWS
+  // stat() fails if there's a trailing slash (PR 88881)
+  path p2;
+  if (p.has_relative_path() && has_trailing_slash(p))
+    {
+      __try
+	{
+	  p2 = p.parent_path();
+	  str = p2.c_str();
+	}
+      __catch(const bad_alloc&)
+	{
+	  ec = std::make_error_code(std::errc::not_enough_memory);
+	  return status;
+	}
+      str = p2.c_str();
+    }
+#endif
+
   stat_type st;
-  if (posix::lstat(p.c_str(), &st))
+  if (posix::lstat(str, &st))
     {
       int err = errno;
       ec.assign(err, std::generic_category());
diff --git a/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc b/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc
index 9e9cd44d460..c2945c90866 100644
--- a/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc
+++ b/libstdc++-v3/testsuite/experimental/filesystem/operations/temp_directory_path.cc
@@ -105,6 +105,8 @@ test03()
   if (!__gnu_test::permissions_are_testable())
     return;
 
+  clean_env();
+
   auto p = __gnu_test::nonexistent_path();
   create_directories(p/"tmp");
   permissions(p, fs::perms::none);
@@ -129,8 +131,10 @@ test03()
 void
 test04()
 {
+  clean_env();
+
   __gnu_test::scoped_file f;
-  set_env("TMPDIR", f.path.string());
+  set_env("TMP", f.path.string());
   std::error_code ec;
   auto r = fs::temp_directory_path(ec);
   VERIFY( ec == std::make_error_code(std::errc::not_a_directory) );