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/new.h"
  12 #include "src/__support/error_or.h"
  13 #include "src/errno/libc_errno.h" // For error macros
  14
  15 namespace LIBC_NAMESPACE {
  16
  17 ErrorOr<Dir *> Dir::open(const char *path) {
  18   auto fd = platform_opendir(path);
  19   if (!fd)
  20     return LIBC_NAMESPACE::Error(fd.error());
  21
  22   LIBC_NAMESPACE::AllocChecker ac;
  23   Dir *dir = new (ac) Dir(fd.value());
  24   if (!ac)
  25     return LIBC_NAMESPACE::Error(ENOMEM);
  26   return dir;
  27 }
  28
  29 ErrorOr<struct ::dirent *> Dir::read() {
  30   MutexLock lock(&mutex);
  31   if (readptr >= fillsize) {
  32     auto readsize = platform_fetch_dirents(fd, buffer);
  33     if (!readsize)
  34       return LIBC_NAMESPACE::Error(readsize.error());
  35     fillsize = readsize.value();
  36     readptr = 0;
  37   }
  38   if (fillsize == 0)
  39     return nullptr;
  40
  41   struct ::dirent *d = reinterpret_cast<struct ::dirent *>(buffer + readptr);
  42 #ifdef __linux__
  43   // The d_reclen field is available on Linux but not required by POSIX.
  44   readptr += d->d_reclen;
  45 #else
  46   // Other platforms have to implement how the read pointer is to be updated.
  47 #error "DIR read pointer update is missing."
  48 #endif
  49   return d;
  50 }
  51
  52 int Dir::close() {
  53   {
  54     MutexLock lock(&mutex);
  55     int retval = platform_closedir(fd);
  56     if (retval != 0)
  57       return retval;
  58   }
  59   delete this;
  60   return 0;
  61 }
  62
  63 } // namespace LIBC_NAMESPACE