Re: [committed] libstdc++: Improve directory iterator abstractions for openat

[Jonathan Wakely <jwakely@redhat.com>]

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On Tue, 28 Jun 2022 at 15:24, Jonathan Wakely via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
> --- a/libstdc++-v3/src/filesystem/dir-common.h
> +++ b/libstdc++-v3/src/filesystem/dir-common.h
> @@ -25,6 +25,7 @@
>  #ifndef _GLIBCXX_DIR_COMMON_H
>  #define _GLIBCXX_DIR_COMMON_H 1
>
> +#include <stdint.h>  // uint32_t
>  #include <string.h>  // strcmp
>  #include <errno.h>
>  #if _GLIBCXX_FILESYSTEM_IS_WINDOWS
> @@ -91,12 +92,50 @@ is_permission_denied_error(int e)
>
>  struct _Dir_base
>  {
> +  // As well as the full pathname (including the directory iterator's path)
> +  // this type contains a file descriptor for a directory and a second pathname
> +  // relative to that directory. The file descriptor and relative pathname
> +  // can be used with POSIX openat and unlinkat.
> +  struct _At_path
> +  {
> +    // No file descriptor given, so interpret the pathname relative to the CWD.
> +    _At_path(const char* p) noexcept

I forgot to consistently use the char_type alias to support wchar_t
paths on Windows. Fixed by the attached patch.

Tested x86_64-linux and x86_64-mingw32, pushed to trunk.

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commit bb1f266a7d602ffee4a070f586351bdfafcb6150
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Jun 28 12:56:19 2022

    libstdc++: Fix filesystem build for Windows
    
    I only half remembered to use char_type instead of char for filesystem
    paths, so that it works with wchar_t on Windows. This fixes the
    bootstrap failure.
    
    libstdc++-v3/ChangeLog:
    
            * src/filesystem/dir-common.h (_Dir_base::_At_path):
            Use char_type consistently for paths.

diff --git a/libstdc++-v3/src/filesystem/dir-common.h b/libstdc++-v3/src/filesystem/dir-common.h
index 4844b1ac453..228fab55afb 100644
--- a/libstdc++-v3/src/filesystem/dir-common.h
+++ b/libstdc++-v3/src/filesystem/dir-common.h
@@ -99,18 +99,22 @@ struct _Dir_base
   struct _At_path
   {
     // No file descriptor given, so interpret the pathname relative to the CWD.
-    _At_path(const char* p) noexcept
+    _At_path(const posix::char_type* p) noexcept
     : pathname(p), dir_fd(fdcwd()), offset(0)
     { }
 
-    _At_path(int fd, const char* p, size_t offset) noexcept
+    _At_path(int fd, const posix::char_type* p, size_t offset) noexcept
     : pathname(p), dir_fd(fd), offset(offset)
     { }
 
-    const char* path() const noexcept { return pathname; }
+    const posix::char_type*
+    path() const noexcept { return pathname; }
 
-    int dir() const noexcept { return dir_fd; }
-    const char* path_at_dir() const noexcept { return pathname + offset; }
+    int
+    dir() const noexcept { return dir_fd; }
+
+    const posix::char_type*
+    path_at_dir() const noexcept { return pathname + offset; }
 
   private:
     const posix::char_type* pathname; // Full path relative to CWD.