libstdc++-v3/src/filesystem/dir-common.h

   1 // Filesystem directory iterator utilities -*- C++ -*-
   2
   3 // Copyright (C) 2014-2018 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 #ifndef _GLIBCXX_DIR_COMMON_H
  26 #define _GLIBCXX_DIR_COMMON_H 1
  27
  28 #include <string.h>  // strcmp
  29 #if _GLIBCXX_FILESYSTEM_IS_WINDOWS
  30 #include <wchar.h>  // wcscmp
  31 #endif
  32 #ifdef _GLIBCXX_HAVE_DIRENT_H
  33 # ifdef _GLIBCXX_HAVE_SYS_TYPES_H
  34 #  include <sys/types.h>
  35 # endif
  36 # include <dirent.h>
  37 #else
  38 # error "the <dirent.h> header is needed to build the Filesystem TS"
  39 #endif
  40
  41 namespace std _GLIBCXX_VISIBILITY(default)
  42 {
  43 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  44 namespace filesystem
  45 {
  46 namespace __gnu_posix
  47 {
  48 #if _GLIBCXX_FILESYSTEM_IS_WINDOWS
  49 // Adapt the Windows _wxxx functions to look like POSIX xxx, but for wchar_t*.
  50 using char_type = wchar_t;
  51 using DIR = ::_WDIR;
  52 using dirent = _wdirent;
  53 inline DIR* opendir(const wchar_t* path) { return ::_wopendir(path); }
  54 inline dirent* readdir(DIR* dir) { return ::_wreaddir(dir); }
  55 inline int closedir(DIR* dir) { return ::_wclosedir(dir); }
  56 #else
  57 using char_type = char;
  58 using DIR = ::DIR;
  59 typedef struct ::dirent dirent;
  60 using ::opendir;
  61 using ::readdir;
  62 using ::closedir;
  63 #endif
  64 } // namespace __gnu_posix
  65
  66 namespace posix = __gnu_posix;
  67
  68 struct _Dir_base
  69 {
  70   _Dir_base(posix::DIR* dirp = nullptr) : dirp(dirp) { }
  71
  72   // If no error occurs then dirp is non-null,
  73   // otherwise null (whether error ignored or not).
  74   _Dir_base(const posix::char_type* pathname, bool skip_permission_denied,
  75             error_code& ec) noexcept
  76   : dirp(posix::opendir(pathname))
  77   {
  78     if (dirp)
  79       ec.clear();
  80     else
  81     {
  82       const int err = errno;
  83       if (err == EACCES && skip_permission_denied)
  84         ec.clear();
  85       else
  86         ec.assign(err, std::generic_category());
  87     }
  88   }
  89
  90   _Dir_base(_Dir_base&& d) : dirp(std::exchange(d.dirp, nullptr)) { }
  91
  92   _Dir_base& operator=(_Dir_base&&) = delete;
  93
  94   ~_Dir_base() { if (dirp) posix::closedir(dirp); }
  95
  96   const posix::dirent*
  97   advance(bool skip_permission_denied, error_code& ec) noexcept
  98   {
  99     ec.clear();
 100
 101     int err = std::exchange(errno, 0);
 102     const posix::dirent* entp = posix::readdir(dirp);
 103     // std::swap cannot be used with Bionic's errno
 104     err = std::exchange(errno, err);
 105
 106     if (entp)
 107       {
 108         // skip past dot and dot-dot
 109         if (is_dot_or_dotdot(entp->d_name))
 110           return advance(skip_permission_denied, ec);
 111         return entp;
 112       }
 113     else if (err)
 114       {
 115         if (err == EACCES && skip_permission_denied)
 116           return nullptr;
 117         ec.assign(err, std::generic_category());
 118         return nullptr;
 119       }
 120     else
 121       {
 122         // reached the end
 123         return nullptr;
 124       }
 125   }
 126
 127   static bool is_dot_or_dotdot(const char* s) noexcept
 128   { return !strcmp(s, ".") || !strcmp(s, ".."); }
 129
 130 #if _GLIBCXX_FILESYSTEM_IS_WINDOWS
 131   static bool is_dot_or_dotdot(const wchar_t* s) noexcept
 132   { return !wcscmp(s, L".") || !wcscmp(s, L".."); }
 133 #endif
 134
 135   posix::DIR*   dirp;
 136 };
 137
 138 } // namespace filesystem
 139
 140 // BEGIN/END macros must be defined before including this file.
 141 _GLIBCXX_BEGIN_NAMESPACE_FILESYSTEM
 142
 143 inline file_type
 144 get_file_type(const std::filesystem::__gnu_posix::dirent& d [[gnu::unused]])
 145 {
 146 #ifdef _GLIBCXX_HAVE_STRUCT_DIRENT_D_TYPE
 147   switch (d.d_type)
 148   {
 149   case DT_BLK:
 150     return file_type::block;
 151   case DT_CHR:
 152     return file_type::character;
 153   case DT_DIR:
 154     return file_type::directory;
 155   case DT_FIFO:
 156     return file_type::fifo;
 157   case DT_LNK:
 158     return file_type::symlink;
 159   case DT_REG:
 160     return file_type::regular;
 161   case DT_SOCK:
 162     return file_type::socket;
 163   case DT_UNKNOWN:
 164     return file_type::unknown;
 165   default:
 166     return file_type::none;
 167   }
 168 #else
 169   return file_type::none;
 170 #endif
 171 }
 172 _GLIBCXX_END_NAMESPACE_FILESYSTEM
 173
 174 _GLIBCXX_END_NAMESPACE_VERSION
 175 } // namespace std
 176
 177 #endif // _GLIBCXX_DIR_COMMON_H