src/filesystem/posix_compat.h - llvm-project/libcxx - Git at Google

 //===----------------------------------------------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//

 //
 // POSIX-like portability helper functions.
 //
 // These generally behave like the proper posix functions, with these
 // exceptions:
 // On Windows, they take paths in wchar_t* form, instead of char* form.
 // The symlink() function is split into two frontends, symlink_file()
 // and symlink_dir().
 //
 // These are provided within an anonymous namespace within the detail
 // namespace - callers need to include this header and call them as
 // detail::function(), regardless of platform.
 //

 #ifndef POSIX_COMPAT_H
 #define POSIX_COMPAT_H

 #include "filesystem"

 #include "filesystem_common.h"

 #if defined(_LIBCPP_WIN32API)
 # define WIN32_LEAN_AND_MEAN
 # define NOMINMAX
 # include <windows.h>
 # include <io.h>
 #else
 # include <unistd.h>
 # include <sys/stat.h>
 # include <sys/statvfs.h>
 #endif
 #include <time.h>

 _LIBCPP_BEGIN_NAMESPACE_FILESYSTEM

 namespace detail {
 namespace {

 #if defined(_LIBCPP_WIN32API)

 // Various C runtime header sets provide more or less of these. As we
 // provide our own implementation, undef all potential defines from the
 // C runtime headers and provide a complete set of macros of our own.

 #undef _S_IFMT
 #undef _S_IFDIR
 #undef _S_IFCHR
 #undef _S_IFIFO
 #undef _S_IFREG
 #undef _S_IFBLK
 #undef _S_IFLNK
 #undef _S_IFSOCK

 #define _S_IFMT   0xF000
 #define _S_IFDIR  0x4000
 #define _S_IFCHR  0x2000
 #define _S_IFIFO  0x1000
 #define _S_IFREG  0x8000
 #define _S_IFBLK  0x6000
 #define _S_IFLNK  0xA000
 #define _S_IFSOCK 0xC000

 #undef S_ISDIR
 #undef S_ISFIFO
 #undef S_ISCHR
 #undef S_ISREG
 #undef S_ISLNK
 #undef S_ISBLK
 #undef S_ISSOCK

 #define S_ISDIR(m)      (((m) & _S_IFMT) == _S_IFDIR)
 #define S_ISCHR(m)      (((m) & _S_IFMT) == _S_IFCHR)
 #define S_ISFIFO(m)     (((m) & _S_IFMT) == _S_IFIFO)
 #define S_ISREG(m)      (((m) & _S_IFMT) == _S_IFREG)
 #define S_ISBLK(m)      (((m) & _S_IFMT) == _S_IFBLK)
 #define S_ISLNK(m)      (((m) & _S_IFMT) == _S_IFLNK)
 #define S_ISSOCK(m)     (((m) & _S_IFMT) == _S_IFSOCK)

 #define O_NONBLOCK 0


 // There were 369 years and 89 leap days from the Windows epoch
 // (1601) to the Unix epoch (1970).
 #define FILE_TIME_OFFSET_SECS (uint64_t(369 * 365 + 89) * (24 * 60 * 60))

 TimeSpec filetime_to_timespec(LARGE_INTEGER li) {
   TimeSpec ret;
   ret.tv_sec = li.QuadPart / 10000000 - FILE_TIME_OFFSET_SECS;
   ret.tv_nsec = (li.QuadPart % 10000000) * 100;
   return ret;
 }

 TimeSpec filetime_to_timespec(FILETIME ft) {
   LARGE_INTEGER li;
   li.LowPart = ft.dwLowDateTime;
   li.HighPart = ft.dwHighDateTime;
   return filetime_to_timespec(li);
 }

 FILETIME timespec_to_filetime(TimeSpec ts) {
   LARGE_INTEGER li;
   li.QuadPart =
       ts.tv_nsec / 100 + (ts.tv_sec + FILE_TIME_OFFSET_SECS) * 10000000;
   FILETIME ft;
   ft.dwLowDateTime = li.LowPart;
   ft.dwHighDateTime = li.HighPart;
   return ft;
 }

 int set_errno(int e = GetLastError()) {
   errno = static_cast<int>(__win_err_to_errc(e));
   return -1;
 }

 class WinHandle {
 public:
   WinHandle(const wchar_t *p, DWORD access, DWORD flags) {
     h = CreateFileW(
         p, access, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
         nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | flags, nullptr);
   }
   ~WinHandle() {
     if (h != INVALID_HANDLE_VALUE)
       CloseHandle(h);
   }
   operator HANDLE() const { return h; }
   operator bool() const { return h != INVALID_HANDLE_VALUE; }

 private:
   HANDLE h;
 };

 int stat_handle(HANDLE h, StatT *buf) {
   FILE_BASIC_INFO basic;
   if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
     return set_errno();
   memset(buf, 0, sizeof(*buf));
   buf->st_mtim = filetime_to_timespec(basic.LastWriteTime);
   buf->st_atim = filetime_to_timespec(basic.LastAccessTime);
   buf->st_mode = 0555; // Read-only
   if (!(basic.FileAttributes & FILE_ATTRIBUTE_READONLY))
     buf->st_mode |= 0222; // Write
   if (basic.FileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
     buf->st_mode |= _S_IFDIR;
   } else {
     buf->st_mode |= _S_IFREG;
   }
   if (basic.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
     FILE_ATTRIBUTE_TAG_INFO tag;
     if (!GetFileInformationByHandleEx(h, FileAttributeTagInfo, &tag,
                                       sizeof(tag)))
       return set_errno();
     if (tag.ReparseTag == IO_REPARSE_TAG_SYMLINK)
       buf->st_mode = (buf->st_mode & ~_S_IFMT) | _S_IFLNK;
   }
   FILE_STANDARD_INFO standard;
   if (!GetFileInformationByHandleEx(h, FileStandardInfo, &standard,
                                     sizeof(standard)))
     return set_errno();
   buf->st_nlink = standard.NumberOfLinks;
   buf->st_size = standard.EndOfFile.QuadPart;
   BY_HANDLE_FILE_INFORMATION info;
   if (!GetFileInformationByHandle(h, &info))
     return set_errno();
   buf->st_dev = info.dwVolumeSerialNumber;
   memcpy(&buf->st_ino.id[0], &info.nFileIndexHigh, 4);
   memcpy(&buf->st_ino.id[4], &info.nFileIndexLow, 4);
   return 0;
 }

 int stat_file(const wchar_t *path, StatT *buf, DWORD flags) {
   WinHandle h(path, FILE_READ_ATTRIBUTES, flags);
   if (!h)
     return set_errno();
   int ret = stat_handle(h, buf);
   return ret;
 }

 int stat(const wchar_t *path, StatT *buf) { return stat_file(path, buf, 0); }

 int lstat(const wchar_t *path, StatT *buf) {
   return stat_file(path, buf, FILE_FLAG_OPEN_REPARSE_POINT);
 }

 int fstat(int fd, StatT *buf) {
   HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
   return stat_handle(h, buf);
 }

 int mkdir(const wchar_t *path, int permissions) {
   (void)permissions;
   return _wmkdir(path);
 }

 int symlink_file_dir(const wchar_t *oldname, const wchar_t *newname,
                      bool is_dir) {
   path dest(oldname);
   dest.make_preferred();
   oldname = dest.c_str();
   DWORD flags = is_dir ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0;
   if (CreateSymbolicLinkW(newname, oldname,
                           flags | SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE))
     return 0;
   int e = GetLastError();
   if (e != ERROR_INVALID_PARAMETER)
     return set_errno(e);
   if (CreateSymbolicLinkW(newname, oldname, flags))
     return 0;
   return set_errno();
 }

 int symlink_file(const wchar_t *oldname, const wchar_t *newname) {
   return symlink_file_dir(oldname, newname, false);
 }

 int symlink_dir(const wchar_t *oldname, const wchar_t *newname) {
   return symlink_file_dir(oldname, newname, true);
 }

 int link(const wchar_t *oldname, const wchar_t *newname) {
   if (CreateHardLinkW(newname, oldname, nullptr))
     return 0;
   return set_errno();
 }

 int remove(const wchar_t *path) {
   detail::WinHandle h(path, DELETE, FILE_FLAG_OPEN_REPARSE_POINT);
   if (!h)
     return set_errno();
   FILE_DISPOSITION_INFO info;
   info.DeleteFile = TRUE;
   if (!SetFileInformationByHandle(h, FileDispositionInfo, &info, sizeof(info)))
     return set_errno();
   return 0;
 }

 int truncate_handle(HANDLE h, off_t length) {
   LARGE_INTEGER size_param;
   size_param.QuadPart = length;
   if (!SetFilePointerEx(h, size_param, 0, FILE_BEGIN))
     return set_errno();
   if (!SetEndOfFile(h))
     return set_errno();
   return 0;
 }

 int ftruncate(int fd, off_t length) {
   HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
   return truncate_handle(h, length);
 }

 int truncate(const wchar_t *path, off_t length) {
   detail::WinHandle h(path, GENERIC_WRITE, 0);
   if (!h)
     return set_errno();
   return truncate_handle(h, length);
 }

 int rename(const wchar_t *from, const wchar_t *to) {
   if (!(MoveFileExW(from, to,
                     MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING |
                         MOVEFILE_WRITE_THROUGH)))
     return set_errno();
   return 0;
 }

 template <class... Args> int open(const wchar_t *filename, Args... args) {
   return _wopen(filename, args...);
 }
 int close(int fd) { return _close(fd); }
 int chdir(const wchar_t *path) { return _wchdir(path); }

 struct StatVFS {
   uint64_t f_frsize;
   uint64_t f_blocks;
   uint64_t f_bfree;
   uint64_t f_bavail;
 };

 int statvfs(const wchar_t *p, StatVFS *buf) {
   path dir = p;
   while (true) {
     error_code local_ec;
     const file_status st = status(dir, local_ec);
     if (!exists(st) || is_directory(st))
       break;
     path parent = dir.parent_path();
     if (parent == dir) {
       errno = ENOENT;
       return -1;
     }
     dir = parent;
   }
   ULARGE_INTEGER free_bytes_available_to_caller, total_number_of_bytes,
       total_number_of_free_bytes;
   if (!GetDiskFreeSpaceExW(dir.c_str(), &free_bytes_available_to_caller,
                            &total_number_of_bytes, &total_number_of_free_bytes))
     return set_errno();
   buf->f_frsize = 1;
   buf->f_blocks = total_number_of_bytes.QuadPart;
   buf->f_bfree = total_number_of_free_bytes.QuadPart;
   buf->f_bavail = free_bytes_available_to_caller.QuadPart;
   return 0;
 }

 wchar_t *getcwd(wchar_t *buff, size_t size) { return _wgetcwd(buff, size); }
 #else
 int symlink_file(const char *oldname, const char *newname) {
   return ::symlink(oldname, newname);
 }
 int symlink_dir(const char *oldname, const char *newname) {
   return ::symlink(oldname, newname);
 }
 using ::chdir;
 using ::close;
 using ::fstat;
 using ::ftruncate;
 using ::getcwd;
 using ::link;
 using ::lstat;
 using ::mkdir;
 using ::open;
 using ::remove;
 using ::rename;
 using ::stat;
 using ::statvfs;
 using ::truncate;

 #define O_BINARY 0

 using StatVFS = struct statvfs;

 #endif

 } // namespace
 } // end namespace detail

 _LIBCPP_END_NAMESPACE_FILESYSTEM

 #endif // POSIX_COMPAT_H
	//===----------------------------------------------------------------------===//
	//
	// 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
	//
	//===----------------------------------------------------------------------===//

	//
	// POSIX-like portability helper functions.
	//
	// These generally behave like the proper posix functions, with these
	// exceptions:
	// On Windows, they take paths in wchar_t* form, instead of char* form.
	// The symlink() function is split into two frontends, symlink_file()
	// and symlink_dir().
	//
	// These are provided within an anonymous namespace within the detail
	// namespace - callers need to include this header and call them as
	// detail::function(), regardless of platform.
	//

	#ifndef POSIX_COMPAT_H
	#define POSIX_COMPAT_H

	#include "filesystem"

	#include "filesystem_common.h"

	#if defined(_LIBCPP_WIN32API)
	# define WIN32_LEAN_AND_MEAN
	# define NOMINMAX
	# include <windows.h>
	# include <io.h>
	#else
	# include <unistd.h>
	# include <sys/stat.h>
	# include <sys/statvfs.h>
	#endif
	#include <time.h>

	_LIBCPP_BEGIN_NAMESPACE_FILESYSTEM

	namespace detail {
	namespace {

	#if defined(_LIBCPP_WIN32API)

	// Various C runtime header sets provide more or less of these. As we
	// provide our own implementation, undef all potential defines from the
	// C runtime headers and provide a complete set of macros of our own.

	#undef _S_IFMT
	#undef _S_IFDIR
	#undef _S_IFCHR
	#undef _S_IFIFO
	#undef _S_IFREG
	#undef _S_IFBLK
	#undef _S_IFLNK
	#undef _S_IFSOCK

	#define _S_IFMT 0xF000
	#define _S_IFDIR 0x4000
	#define _S_IFCHR 0x2000
	#define _S_IFIFO 0x1000
	#define _S_IFREG 0x8000
	#define _S_IFBLK 0x6000
	#define _S_IFLNK 0xA000
	#define _S_IFSOCK 0xC000

	#undef S_ISDIR
	#undef S_ISFIFO
	#undef S_ISCHR
	#undef S_ISREG
	#undef S_ISLNK
	#undef S_ISBLK
	#undef S_ISSOCK

	#define S_ISDIR(m) (((m) & _S_IFMT) == _S_IFDIR)
	#define S_ISCHR(m) (((m) & _S_IFMT) == _S_IFCHR)
	#define S_ISFIFO(m) (((m) & _S_IFMT) == _S_IFIFO)
	#define S_ISREG(m) (((m) & _S_IFMT) == _S_IFREG)
	#define S_ISBLK(m) (((m) & _S_IFMT) == _S_IFBLK)
	#define S_ISLNK(m) (((m) & _S_IFMT) == _S_IFLNK)
	#define S_ISSOCK(m) (((m) & _S_IFMT) == _S_IFSOCK)

	#define O_NONBLOCK 0


	// There were 369 years and 89 leap days from the Windows epoch
	// (1601) to the Unix epoch (1970).
	#define FILE_TIME_OFFSET_SECS (uint64_t(369 * 365 + 89) * (24 * 60 * 60))

	TimeSpec filetime_to_timespec(LARGE_INTEGER li) {
	TimeSpec ret;
	ret.tv_sec = li.QuadPart / 10000000 - FILE_TIME_OFFSET_SECS;
	ret.tv_nsec = (li.QuadPart % 10000000) * 100;
	return ret;
	}

	TimeSpec filetime_to_timespec(FILETIME ft) {
	LARGE_INTEGER li;
	li.LowPart = ft.dwLowDateTime;
	li.HighPart = ft.dwHighDateTime;
	return filetime_to_timespec(li);
	}

	FILETIME timespec_to_filetime(TimeSpec ts) {
	LARGE_INTEGER li;
	li.QuadPart =
	ts.tv_nsec / 100 + (ts.tv_sec + FILE_TIME_OFFSET_SECS) * 10000000;
	FILETIME ft;
	ft.dwLowDateTime = li.LowPart;
	ft.dwHighDateTime = li.HighPart;
	return ft;
	}

	int set_errno(int e = GetLastError()) {
	errno = static_cast<int>(__win_err_to_errc(e));
	return -1;
	}

	class WinHandle {
	public:
	WinHandle(const wchar_t *p, DWORD access, DWORD flags) {
	h = CreateFileW(
	p, access, FILE_SHARE_READ \| FILE_SHARE_WRITE \| FILE_SHARE_DELETE,
	nullptr, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS \| flags, nullptr);
	}
	~WinHandle() {
	if (h != INVALID_HANDLE_VALUE)
	CloseHandle(h);
	}
	operator HANDLE() const { return h; }
	operator bool() const { return h != INVALID_HANDLE_VALUE; }

	private:
	HANDLE h;
	};

	int stat_handle(HANDLE h, StatT *buf) {
	FILE_BASIC_INFO basic;
	if (!GetFileInformationByHandleEx(h, FileBasicInfo, &basic, sizeof(basic)))
	return set_errno();
	memset(buf, 0, sizeof(*buf));
	buf->st_mtim = filetime_to_timespec(basic.LastWriteTime);
	buf->st_atim = filetime_to_timespec(basic.LastAccessTime);
	buf->st_mode = 0555; // Read-only
	if (!(basic.FileAttributes & FILE_ATTRIBUTE_READONLY))
	buf->st_mode \|= 0222; // Write
	if (basic.FileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
	buf->st_mode \|= _S_IFDIR;
	} else {
	buf->st_mode \|= _S_IFREG;
	}
	if (basic.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
	FILE_ATTRIBUTE_TAG_INFO tag;
	if (!GetFileInformationByHandleEx(h, FileAttributeTagInfo, &tag,
	sizeof(tag)))
	return set_errno();
	if (tag.ReparseTag == IO_REPARSE_TAG_SYMLINK)
	buf->st_mode = (buf->st_mode & ~_S_IFMT) \| _S_IFLNK;
	}
	FILE_STANDARD_INFO standard;
	if (!GetFileInformationByHandleEx(h, FileStandardInfo, &standard,
	sizeof(standard)))
	return set_errno();
	buf->st_nlink = standard.NumberOfLinks;
	buf->st_size = standard.EndOfFile.QuadPart;
	BY_HANDLE_FILE_INFORMATION info;
	if (!GetFileInformationByHandle(h, &info))
	return set_errno();
	buf->st_dev = info.dwVolumeSerialNumber;
	memcpy(&buf->st_ino.id[0], &info.nFileIndexHigh, 4);
	memcpy(&buf->st_ino.id[4], &info.nFileIndexLow, 4);
	return 0;
	}

	int stat_file(const wchar_t path, StatT buf, DWORD flags) {
	WinHandle h(path, FILE_READ_ATTRIBUTES, flags);
	if (!h)
	return set_errno();
	int ret = stat_handle(h, buf);
	return ret;
	}

	int stat(const wchar_t path, StatT buf) { return stat_file(path, buf, 0); }

	int lstat(const wchar_t path, StatT buf) {
	return stat_file(path, buf, FILE_FLAG_OPEN_REPARSE_POINT);
	}

	int fstat(int fd, StatT *buf) {
	HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
	return stat_handle(h, buf);
	}

	int mkdir(const wchar_t *path, int permissions) {
	(void)permissions;
	return _wmkdir(path);
	}

	int symlink_file_dir(const wchar_t oldname, const wchar_t newname,
	bool is_dir) {
	path dest(oldname);
	dest.make_preferred();
	oldname = dest.c_str();
	DWORD flags = is_dir ? SYMBOLIC_LINK_FLAG_DIRECTORY : 0;
	if (CreateSymbolicLinkW(newname, oldname,
	flags \| SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE))
	return 0;
	int e = GetLastError();
	if (e != ERROR_INVALID_PARAMETER)
	return set_errno(e);
	if (CreateSymbolicLinkW(newname, oldname, flags))
	return 0;
	return set_errno();
	}

	int symlink_file(const wchar_t oldname, const wchar_t newname) {
	return symlink_file_dir(oldname, newname, false);
	}

	int symlink_dir(const wchar_t oldname, const wchar_t newname) {
	return symlink_file_dir(oldname, newname, true);
	}

	int link(const wchar_t oldname, const wchar_t newname) {
	if (CreateHardLinkW(newname, oldname, nullptr))
	return 0;
	return set_errno();
	}

	int remove(const wchar_t *path) {
	detail::WinHandle h(path, DELETE, FILE_FLAG_OPEN_REPARSE_POINT);
	if (!h)
	return set_errno();
	FILE_DISPOSITION_INFO info;
	info.DeleteFile = TRUE;
	if (!SetFileInformationByHandle(h, FileDispositionInfo, &info, sizeof(info)))
	return set_errno();
	return 0;
	}

	int truncate_handle(HANDLE h, off_t length) {
	LARGE_INTEGER size_param;
	size_param.QuadPart = length;
	if (!SetFilePointerEx(h, size_param, 0, FILE_BEGIN))
	return set_errno();
	if (!SetEndOfFile(h))
	return set_errno();
	return 0;
	}

	int ftruncate(int fd, off_t length) {
	HANDLE h = reinterpret_cast<HANDLE>(_get_osfhandle(fd));
	return truncate_handle(h, length);
	}

	int truncate(const wchar_t *path, off_t length) {
	detail::WinHandle h(path, GENERIC_WRITE, 0);
	if (!h)
	return set_errno();
	return truncate_handle(h, length);
	}

	int rename(const wchar_t from, const wchar_t to) {
	if (!(MoveFileExW(from, to,
	MOVEFILE_COPY_ALLOWED \| MOVEFILE_REPLACE_EXISTING \|
	MOVEFILE_WRITE_THROUGH)))
	return set_errno();
	return 0;
	}

	template <class... Args> int open(const wchar_t *filename, Args... args) {
	return _wopen(filename, args...);
	}
	int close(int fd) { return _close(fd); }
	int chdir(const wchar_t *path) { return _wchdir(path); }

	struct StatVFS {
	uint64_t f_frsize;
	uint64_t f_blocks;
	uint64_t f_bfree;
	uint64_t f_bavail;
	};

	int statvfs(const wchar_t p, StatVFS buf) {
	path dir = p;
	while (true) {
	error_code local_ec;
	const file_status st = status(dir, local_ec);
	if (!exists(st) \|\| is_directory(st))
	break;
	path parent = dir.parent_path();
	if (parent == dir) {
	errno = ENOENT;
	return -1;
	}
	dir = parent;
	}
	ULARGE_INTEGER free_bytes_available_to_caller, total_number_of_bytes,
	total_number_of_free_bytes;
	if (!GetDiskFreeSpaceExW(dir.c_str(), &free_bytes_available_to_caller,
	&total_number_of_bytes, &total_number_of_free_bytes))
	return set_errno();
	buf->f_frsize = 1;
	buf->f_blocks = total_number_of_bytes.QuadPart;
	buf->f_bfree = total_number_of_free_bytes.QuadPart;
	buf->f_bavail = free_bytes_available_to_caller.QuadPart;
	return 0;
	}

	wchar_t getcwd(wchar_t buff, size_t size) { return _wgetcwd(buff, size); }
	#else
	int symlink_file(const char oldname, const char newname) {
	return ::symlink(oldname, newname);
	}
	int symlink_dir(const char oldname, const char newname) {
	return ::symlink(oldname, newname);
	}
	using ::chdir;
	using ::close;
	using ::fstat;
	using ::ftruncate;
	using ::getcwd;
	using ::link;
	using ::lstat;
	using ::mkdir;
	using ::open;
	using ::remove;
	using ::rename;
	using ::stat;
	using ::statvfs;
	using ::truncate;

	#define O_BINARY 0

	using StatVFS = struct statvfs;

	#endif

	} // namespace
	} // end namespace detail

	_LIBCPP_END_NAMESPACE_FILESYSTEM

	#endif // POSIX_COMPAT_H