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[libcxx] Hook up a number of operation functions to their windows cou…
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…nterparts

Use the corresponding wchar functions, named "_wfunc" instead of "func",
where feasible, or reimplement functions with native windows APIs.

Differential Revision: https://reviews.llvm.org/D91143
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@mstorsjo
mstorsjo committed Jan 29, 2021
1 parent 592d623 commit efec3cc
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Showing 2 changed files with 124 additions and 19 deletions.
41 changes: 22 additions & 19 deletions libcxx/src/filesystem/operations.cpp
View file
Expand Up @@ -405,7 +405,7 @@ struct FileDescriptor {
static FileDescriptor create(const path* p, error_code& ec, Args... args) {
ec.clear();
int fd;
if ((fd = ::open(p->c_str(), args...)) == -1) {
if ((fd = detail::open(p->c_str(), args...)) == -1) {
ec = capture_errno();
return FileDescriptor{p};
}
Expand All @@ -431,7 +431,7 @@ struct FileDescriptor {

void close() noexcept {
if (fd != -1)
::close(fd);
detail::close(fd);
fd = -1;
}

Expand Down Expand Up @@ -521,7 +521,7 @@ file_status posix_lstat(path const& p, error_code* ec) {

// http://pubs.opengroup.org/onlinepubs/9699919799/functions/ftruncate.html
bool posix_ftruncate(const FileDescriptor& fd, off_t to_size, error_code& ec) {
if (::ftruncate(fd.fd, to_size) == -1) {
if (detail::ftruncate(fd.fd, to_size) == -1) {
ec = capture_errno();
return true;
}
Expand Down Expand Up @@ -828,8 +828,8 @@ bool __copy_file(const path& from, const path& to, copy_options options,
ErrorHandler<bool> err("copy_file", ec, &to, &from);

error_code m_ec;
FileDescriptor from_fd =
FileDescriptor::create_with_status(&from, m_ec, O_RDONLY | O_NONBLOCK);
FileDescriptor from_fd = FileDescriptor::create_with_status(
&from, m_ec, O_RDONLY | O_NONBLOCK | O_BINARY);
if (m_ec)
return err.report(m_ec);

Expand Down Expand Up @@ -881,7 +881,7 @@ bool __copy_file(const path& from, const path& to, copy_options options,

// Don't truncate right away. We may not be opening the file we originally
// looked at; we'll check this later.
int to_open_flags = O_WRONLY;
int to_open_flags = O_WRONLY | O_BINARY;
if (!to_exists)
to_open_flags |= O_CREAT;
FileDescriptor to_fd = FileDescriptor::create_with_status(
Expand Down Expand Up @@ -917,10 +917,13 @@ void __copy_symlink(const path& existing_symlink, const path& new_symlink,
if (ec && *ec) {
return;
}
// NOTE: proposal says you should detect if you should call
// create_symlink or create_directory_symlink. I don't think this
// is needed with POSIX
__create_symlink(real_path, new_symlink, ec);
#if defined(_LIBCPP_WIN32API)
error_code local_ec;
if (is_directory(real_path, local_ec))
__create_directory_symlink(real_path, new_symlink, ec);
else
#endif
__create_symlink(real_path, new_symlink, ec);
}

bool __create_directories(const path& p, error_code* ec) {
Expand Down Expand Up @@ -953,7 +956,7 @@ bool __create_directories(const path& p, error_code* ec) {
bool __create_directory(const path& p, error_code* ec) {
ErrorHandler<bool> err("create_directory", ec, &p);

if (::mkdir(p.c_str(), static_cast<int>(perms::all)) == 0)
if (detail::mkdir(p.c_str(), static_cast<int>(perms::all)) == 0)
return true;

if (errno == EEXIST) {
Expand Down Expand Up @@ -981,7 +984,7 @@ bool __create_directory(path const& p, path const& attributes, error_code* ec) {
return err.report(errc::not_a_directory,
"the specified attribute path is invalid");

if (::mkdir(p.c_str(), attr_stat.st_mode) == 0)
if (detail::mkdir(p.c_str(), attr_stat.st_mode) == 0)
return true;

if (errno == EEXIST) {
Expand All @@ -1000,19 +1003,19 @@ bool __create_directory(path const& p, path const& attributes, error_code* ec) {
void __create_directory_symlink(path const& from, path const& to,
error_code* ec) {
ErrorHandler<void> err("create_directory_symlink", ec, &from, &to);
if (::symlink(from.c_str(), to.c_str()) != 0)
if (detail::symlink_dir(from.c_str(), to.c_str()) == -1)
return err.report(capture_errno());
}

void __create_hard_link(const path& from, const path& to, error_code* ec) {
ErrorHandler<void> err("create_hard_link", ec, &from, &to);
if (::link(from.c_str(), to.c_str()) == -1)
if (detail::link(from.c_str(), to.c_str()) == -1)
return err.report(capture_errno());
}

void __create_symlink(path const& from, path const& to, error_code* ec) {
ErrorHandler<void> err("create_symlink", ec, &from, &to);
if (::symlink(from.c_str(), to.c_str()) == -1)
if (detail::symlink_file(from.c_str(), to.c_str()) == -1)
return err.report(capture_errno());
}

Expand All @@ -1032,7 +1035,7 @@ path __current_path(error_code* ec) {

void __current_path(const path& p, error_code* ec) {
ErrorHandler<void> err("current_path", ec, &p);
if (::chdir(p.c_str()) == -1)
if (detail::chdir(p.c_str()) == -1)
err.report(capture_errno());
}

Expand Down Expand Up @@ -1236,7 +1239,7 @@ path __read_symlink(const path& p, error_code* ec) {

bool __remove(const path& p, error_code* ec) {
ErrorHandler<bool> err("remove", ec, &p);
if (::remove(p.c_str()) == -1) {
if (detail::remove(p.c_str()) == -1) {
if (errno != ENOENT)
err.report(capture_errno());
return false;
Expand Down Expand Up @@ -1285,13 +1288,13 @@ uintmax_t __remove_all(const path& p, error_code* ec) {

void __rename(const path& from, const path& to, error_code* ec) {
ErrorHandler<void> err("rename", ec, &from, &to);
if (::rename(from.c_str(), to.c_str()) == -1)
if (detail::rename(from.c_str(), to.c_str()) == -1)
err.report(capture_errno());
}

void __resize_file(const path& p, uintmax_t size, error_code* ec) {
ErrorHandler<void> err("resize_file", ec, &p);
if (::truncate(p.c_str(), static_cast< ::off_t>(size)) == -1)
if (detail::truncate(p.c_str(), static_cast< ::off_t>(size)) == -1)
return err.report(capture_errno());
}

Expand Down
102 changes: 102 additions & 0 deletions libcxx/src/filesystem/posix_compat.h
View file
Expand Up @@ -12,6 +12,8 @@
// 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
Expand Down Expand Up @@ -82,6 +84,8 @@ namespace {
#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).
Expand Down Expand Up @@ -190,10 +194,108 @@ 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) {
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); }
#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 ::link;
using ::lstat;
using ::mkdir;
using ::open;
using ::remove;
using ::rename;
using ::stat;
using ::truncate;

#define O_BINARY 0

#endif

} // namespace
Expand Down

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