//===----------------------------------------------------------------------===////
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===////
#ifndef FILESYSTEM_FILE_DESCRIPTOR_H
#define FILESYSTEM_FILE_DESCRIPTOR_H
#include <__config>
#include <cstdint>
#include <filesystem>
#include <string_view>
#include <system_error>
#include <utility>
#include "error.h"
#include "posix_compat.h"
#include "time_utils.h"
#if defined(_LIBCPP_WIN32API)
# define WIN32_LEAN_AND_MEAN
# define NOMINMAX
# include <windows.h>
#else
# include <dirent.h> // for DIR & friends
# include <fcntl.h> // values for fchmodat
# include <sys/stat.h>
# include <sys/statvfs.h>
# include <unistd.h>
#endif // defined(_LIBCPP_WIN32API)
_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM
namespace detail {
#if !defined(_LIBCPP_WIN32API)
# if defined(DT_BLK)
template <class DirEntT, class = decltype(DirEntT::d_type)>
file_type get_file_type(DirEntT* ent, int) {
switch (ent->d_type) {
case DT_BLK:
return file_type::block;
case DT_CHR:
return file_type::character;
case DT_DIR:
return file_type::directory;
case DT_FIFO:
return file_type::fifo;
case DT_LNK:
return file_type::symlink;
case DT_REG:
return file_type::regular;
case DT_SOCK:
return file_type::socket;
// Unlike in lstat, hitting "unknown" here simply means that the underlying
// filesystem doesn't support d_type. Report is as 'none' so we correctly
// set the cache to empty.
case DT_UNKNOWN:
break;
}
return file_type::none;
}
# endif // defined(DT_BLK)
template <class DirEntT>
file_type get_file_type(DirEntT*, long) {
return file_type::none;
}
inline pair<string_view, file_type> posix_readdir(DIR* dir_stream, error_code& ec) {
struct dirent* dir_entry_ptr = nullptr;
errno = 0; // zero errno in order to detect errors
ec.clear();
if ((dir_entry_ptr = ::readdir(dir_stream)) == nullptr) {
if (errno)
ec = capture_errno();
return {};
} else {
return {dir_entry_ptr->d_name, get_file_type(dir_entry_ptr, 0)};
}
}
#else // _LIBCPP_WIN32API
inline file_type get_file_type(const WIN32_FIND_DATAW& data) {
if (data.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT && data.dwReserved0 == IO_REPARSE_TAG_SYMLINK)
return file_type::symlink;
if (data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
return file_type::directory;
return file_type::regular;
}
inline uintmax_t get_file_size(const WIN32_FIND_DATAW& data) {
return (static_cast<uint64_t>(data.nFileSizeHigh) << 32) + data.nFileSizeLow;
}
inline file_time_type get_write_time(const WIN32_FIND_DATAW& data) {
ULARGE_INTEGER tmp;
const FILETIME& time = data.ftLastWriteTime;
tmp.u.LowPart = time.dwLowDateTime;
tmp.u.HighPart = time.dwHighDateTime;
return file_time_type(file_time_type::duration(tmp.QuadPart));
}
#endif // !_LIBCPP_WIN32API
// POSIX HELPERS
using value_type = path::value_type;
using string_type = path::string_type;
struct FileDescriptor {
const path& name;
int fd = -1;
StatT m_stat;
file_status m_status;
template <class... Args>
static FileDescriptor create(const path* p, error_code& ec, Args... args) {
ec.clear();
int fd;
#ifdef _LIBCPP_WIN32API
// TODO: most of the filesystem implementation uses native Win32 calls
// (mostly via posix_compat.h). However, here we use the C-runtime APIs to
// open a file, because we subsequently pass the C-runtime fd to
// `std::[io]fstream::__open(int fd)` in order to implement copy_file.
//
// Because we're calling the windows C-runtime, win32 error codes are
// translated into C error numbers by the C runtime, and returned in errno,
// rather than being accessible directly via GetLastError.
//
// Ideally copy_file should be calling the Win32 CopyFile2 function, which
// works on paths, not open files -- at which point this FileDescriptor type
// will no longer be needed on windows at all.
fd = ::_wopen(p->c_str(), args...);
#else
fd = open(p->c_str(), args...);
#endif
if (fd == -1) {
ec = capture_errno();
return FileDescriptor{p};
}
return FileDescriptor(p, fd);
}
template <class... Args>
static FileDescriptor create_with_status(const path* p, error_code& ec, Args... args) {
FileDescriptor fd = create(p, ec, args...);
if (!ec)
fd.refresh_status(ec);
return fd;
}
file_status get_status() const { return m_status; }
StatT const& get_stat() const { return m_stat; }
bool status_known() const { return filesystem::status_known(m_status); }
file_status refresh_status(error_code& ec);
void close() noexcept {
if (fd != -1) {
#ifdef _LIBCPP_WIN32API
::_close(fd);
#else
::close(fd);
#endif
// FIXME: shouldn't this return an error_code?
}
fd = -1;
}
FileDescriptor(FileDescriptor&& other)
: name(other.name), fd(other.fd), m_stat(other.m_stat), m_status(other.m_status) {
other.fd = -1;
other.m_status = file_status{};
}
~FileDescriptor() { close(); }
FileDescriptor(FileDescriptor const&) = delete;
FileDescriptor& operator=(FileDescriptor const&) = delete;
private:
explicit FileDescriptor(const path* p, int descriptor = -1) : name(*p), fd(descriptor) {}
};
inline perms posix_get_perms(const StatT& st) noexcept { return static_cast<perms>(st.st_mode) & perms::mask; }
inline file_status create_file_status(error_code& m_ec, path const& p, const StatT& path_stat, error_code* ec) {
if (ec)
*ec = m_ec;
if (m_ec && (m_ec.value() == ENOENT || m_ec.value() == ENOTDIR)) {
return file_status(file_type::not_found);
} else if (m_ec) {
ErrorHandler<void> err("posix_stat", ec, &p);
err.report(m_ec, "failed to determine attributes for the specified path");
return file_status(file_type::none);
}
// else
file_status fs_tmp;
auto const mode = path_stat.st_mode;
if (S_ISLNK(mode))
fs_tmp.type(file_type::symlink);
else if (S_ISREG(mode))
fs_tmp.type(file_type::regular);
else if (S_ISDIR(mode))
fs_tmp.type(file_type::directory);
else if (S_ISBLK(mode))
fs_tmp.type(file_type::block);
else if (S_ISCHR(mode))
fs_tmp.type(file_type::character);
else if (S_ISFIFO(mode))
fs_tmp.type(file_type::fifo);
else if (S_ISSOCK(mode))
fs_tmp.type(file_type::socket);
else
fs_tmp.type(file_type::unknown);
fs_tmp.permissions(detail::posix_get_perms(path_stat));
return fs_tmp;
}
inline file_status posix_stat(path const& p, StatT& path_stat, error_code* ec) {
error_code m_ec;
if (detail::stat(p.c_str(), &path_stat) == -1)
m_ec = detail::capture_errno();
return create_file_status(m_ec, p, path_stat, ec);
}
inline file_status posix_stat(path const& p, error_code* ec) {
StatT path_stat;
return posix_stat(p, path_stat, ec);
}
inline file_status posix_lstat(path const& p, StatT& path_stat, error_code* ec) {
error_code m_ec;
if (detail::lstat(p.c_str(), &path_stat) == -1)
m_ec = detail::capture_errno();
return create_file_status(m_ec, p, path_stat, ec);
}
inline file_status posix_lstat(path const& p, error_code* ec) {
StatT path_stat;
return posix_lstat(p, path_stat, ec);
}
// http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
inline bool posix_ftruncate(const FileDescriptor& fd, off_t to_size, error_code& ec) {
if (detail::ftruncate(fd.fd, to_size) == -1) {
ec = capture_errno();
return true;
}
ec.clear();
return false;
}
inline bool posix_fchmod(const FileDescriptor& fd, const StatT& st, error_code& ec) {
if (detail::fchmod(fd.fd, st.st_mode) == -1) {
ec = capture_errno();
return true;
}
ec.clear();
return false;
}
inline bool stat_equivalent(const StatT& st1, const StatT& st2) {
return (st1.st_dev == st2.st_dev && st1.st_ino == st2.st_ino);
}
inline file_status FileDescriptor::refresh_status(error_code& ec) {
// FD must be open and good.
m_status = file_status{};
m_stat = {};
error_code m_ec;
if (detail::fstat(fd, &m_stat) == -1)
m_ec = capture_errno();
m_status = create_file_status(m_ec, name, m_stat, &ec);
return m_status;
}
} // end namespace detail
_LIBCPP_END_NAMESPACE_FILESYSTEM
#endif // FILESYSTEM_FILE_DESCRIPTOR_H
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