libc/src/__support/File/dir.cpp

   1 //===--- Implementation of a platform independent Dir data structure ------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "dir.h"
  10
  11 #include "src/__support/CPP/mutex.h" // lock_guard
  12 #include "src/__support/CPP/new.h"
  13 #include "src/__support/error_or.h"
  14 #include "src/__support/macros/config.h"
  15 #include "src/errno/libc_errno.h" // For error macros
  16
  17 namespace LIBC_NAMESPACE_DECL {
  18
  19 ErrorOr<Dir *> Dir::open(const char *path) {
  20   auto fd = platform_opendir(path);
  21   if (!fd)
  22     return LIBC_NAMESPACE::Error(fd.error());
  23
  24   LIBC_NAMESPACE::AllocChecker ac;
  25   Dir *dir = new (ac) Dir(fd.value());
  26   if (!ac)
  27     return LIBC_NAMESPACE::Error(ENOMEM);
  28   return dir;
  29 }
  30
  31 ErrorOr<struct ::dirent *> Dir::read() {
  32   cpp::lock_guard lock(mutex);
  33   if (readptr >= fillsize) {
  34     auto readsize = platform_fetch_dirents(fd, buffer);
  35     if (!readsize)
  36       return LIBC_NAMESPACE::Error(readsize.error());
  37     fillsize = readsize.value();
  38     readptr = 0;
  39   }
  40   if (fillsize == 0)
  41     return nullptr;
  42
  43   struct ::dirent *d = reinterpret_cast<struct ::dirent *>(buffer + readptr);
  44 #ifdef __linux__
  45   // The d_reclen field is available on Linux but not required by POSIX.
  46   readptr += d->d_reclen;
  47 #else
  48   // Other platforms have to implement how the read pointer is to be updated.
  49 #error "DIR read pointer update is missing."
  50 #endif
  51   return d;
  52 }
  53
  54 int Dir::close() {
  55   {
  56     cpp::lock_guard lock(mutex);
  57     int retval = platform_closedir(fd);
  58     if (retval != 0)
  59       return retval;
  60   }
  61   delete this;
  62   return 0;
  63 }
  64
  65 } // namespace LIBC_NAMESPACE_DECL