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Merged
merged 3 commits into from
Oct 21, 2024
Merged

speedup directory traversal on windows #131972

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22a9a8b
replace FindFirstFileW with FindFirstFileExW and regenerate bindings
klensy Oct 20, 2024
8abe67c
replace FindFirstFileW with FindFirstFileExW and apply optimization
klensy Oct 20, 2024
2920ed0
fix docs
klensy Oct 20, 2024
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2 changes: 1 addition & 1 deletion library/std/src/fs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2618,7 +2618,7 @@ pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
/// # Platform-specific behavior
///
/// This function currently corresponds to the `opendir` function on Unix
/// and the `FindFirstFile` function on Windows. Advancing the iterator
/// and the `FindFirstFileEx` function on Windows. Advancing the iterator
/// currently corresponds to `readdir` on Unix and `FindNextFile` on Windows.
/// Note that, this [may change in the future][changes].
///
Expand Down
4 changes: 3 additions & 1 deletion library/std/src/sys/pal/windows/c/bindings.txt
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Expand Up @@ -2337,7 +2337,9 @@ Windows.Win32.Storage.FileSystem.FileStandardInfo
Windows.Win32.Storage.FileSystem.FileStorageInfo
Windows.Win32.Storage.FileSystem.FileStreamInfo
Windows.Win32.Storage.FileSystem.FindClose
Windows.Win32.Storage.FileSystem.FindFirstFileW
Windows.Win32.Storage.FileSystem.FindExInfoBasic
Windows.Win32.Storage.FileSystem.FindExSearchNameMatch
Windows.Win32.Storage.FileSystem.FindFirstFileExW
Windows.Win32.Storage.FileSystem.FindNextFileW
Windows.Win32.Storage.FileSystem.FlushFileBuffers
Windows.Win32.Storage.FileSystem.GetFileAttributesW
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8 changes: 6 additions & 2 deletions library/std/src/sys/pal/windows/c/windows_sys.rs
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Expand Up @@ -26,7 +26,7 @@ windows_targets::link!("kernel32.dll" "system" fn DeviceIoControl(hdevice : HAND
windows_targets::link!("kernel32.dll" "system" fn DuplicateHandle(hsourceprocesshandle : HANDLE, hsourcehandle : HANDLE, htargetprocesshandle : HANDLE, lptargethandle : *mut HANDLE, dwdesiredaccess : u32, binherithandle : BOOL, dwoptions : DUPLICATE_HANDLE_OPTIONS) -> BOOL);
windows_targets::link!("kernel32.dll" "system" fn ExitProcess(uexitcode : u32) -> !);
windows_targets::link!("kernel32.dll" "system" fn FindClose(hfindfile : HANDLE) -> BOOL);
windows_targets::link!("kernel32.dll" "system" fn FindFirstFileW(lpfilename : PCWSTR, lpfindfiledata : *mut WIN32_FIND_DATAW) -> HANDLE);
windows_targets::link!("kernel32.dll" "system" fn FindFirstFileExW(lpfilename : PCWSTR, finfolevelid : FINDEX_INFO_LEVELS, lpfindfiledata : *mut core::ffi::c_void, fsearchop : FINDEX_SEARCH_OPS, lpsearchfilter : *const core::ffi::c_void, dwadditionalflags : FIND_FIRST_EX_FLAGS) -> HANDLE);
windows_targets::link!("kernel32.dll" "system" fn FindNextFileW(hfindfile : HANDLE, lpfindfiledata : *mut WIN32_FIND_DATAW) -> BOOL);
windows_targets::link!("kernel32.dll" "system" fn FlushFileBuffers(hfile : HANDLE) -> BOOL);
windows_targets::link!("kernel32.dll" "system" fn FormatMessageW(dwflags : FORMAT_MESSAGE_OPTIONS, lpsource : *const core::ffi::c_void, dwmessageid : u32, dwlanguageid : u32, lpbuffer : PWSTR, nsize : u32, arguments : *const *const i8) -> u32);
Expand Down Expand Up @@ -2501,6 +2501,9 @@ pub const FILE_WRITE_ATTRIBUTES: FILE_ACCESS_RIGHTS = 256u32;
pub const FILE_WRITE_DATA: FILE_ACCESS_RIGHTS = 2u32;
pub const FILE_WRITE_EA: FILE_ACCESS_RIGHTS = 16u32;
pub const FILE_WRITE_THROUGH: NTCREATEFILE_CREATE_OPTIONS = 2u32;
pub type FINDEX_INFO_LEVELS = i32;
pub type FINDEX_SEARCH_OPS = i32;
pub type FIND_FIRST_EX_FLAGS = u32;
pub const FIONBIO: i32 = -2147195266i32;
#[repr(C)]
#[cfg(any(target_arch = "aarch64", target_arch = "arm64ec", target_arch = "x86_64"))]
Expand Down Expand Up @@ -2565,6 +2568,8 @@ pub const FileRenameInfoEx: FILE_INFO_BY_HANDLE_CLASS = 22i32;
pub const FileStandardInfo: FILE_INFO_BY_HANDLE_CLASS = 1i32;
pub const FileStorageInfo: FILE_INFO_BY_HANDLE_CLASS = 16i32;
pub const FileStreamInfo: FILE_INFO_BY_HANDLE_CLASS = 7i32;
pub const FindExInfoBasic: FINDEX_INFO_LEVELS = 1i32;
pub const FindExSearchNameMatch: FINDEX_SEARCH_OPS = 0i32;
pub type GENERIC_ACCESS_RIGHTS = u32;
pub const GENERIC_ALL: GENERIC_ACCESS_RIGHTS = 268435456u32;
pub const GENERIC_EXECUTE: GENERIC_ACCESS_RIGHTS = 536870912u32;
Expand Down Expand Up @@ -3307,7 +3312,6 @@ pub struct XSAVE_FORMAT {
pub XmmRegisters: [M128A; 8],
pub Reserved4: [u8; 224],
}

#[cfg(target_arch = "arm")]
#[repr(C)]
pub struct WSADATA {
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41 changes: 31 additions & 10 deletions library/std/src/sys/pal/windows/fs.rs
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Expand Up @@ -114,7 +114,7 @@ impl Iterator for ReadDir {
fn next(&mut self) -> Option<io::Result<DirEntry>> {
if self.handle.0 == c::INVALID_HANDLE_VALUE {
// This iterator was initialized with an `INVALID_HANDLE_VALUE` as its handle.
// Simply return `None` because this is only the case when `FindFirstFileW` in
// Simply return `None` because this is only the case when `FindFirstFileExW` in
// the construction of this iterator returns `ERROR_FILE_NOT_FOUND` which means
// no matchhing files can be found.
return None;
Expand Down Expand Up @@ -1047,8 +1047,22 @@ pub fn readdir(p: &Path) -> io::Result<ReadDir> {
let path = maybe_verbatim(&star)?;

unsafe {
let mut wfd = mem::zeroed();
let find_handle = c::FindFirstFileW(path.as_ptr(), &mut wfd);
let mut wfd: c::WIN32_FIND_DATAW = mem::zeroed();
// this is like FindFirstFileW (see https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-findfirstfileexw),
// but with FindExInfoBasic it should skip filling WIN32_FIND_DATAW.cAlternateFileName
// (see https://learn.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-win32_find_dataw)
// (which will be always null string value and currently unused) and should be faster.
//
// We can pass FIND_FIRST_EX_LARGE_FETCH to dwAdditionalFlags to speed up things more,
// but as we don't know user's use profile of this function, lets be conservative.
let find_handle = c::FindFirstFileExW(
path.as_ptr(),
c::FindExInfoBasic,
&mut wfd as *mut _ as _,
c::FindExSearchNameMatch,
ptr::null(),
0,
);

if find_handle != c::INVALID_HANDLE_VALUE {
Ok(ReadDir {
Expand All @@ -1057,7 +1071,7 @@ pub fn readdir(p: &Path) -> io::Result<ReadDir> {
first: Some(wfd),
})
} else {
// The status `ERROR_FILE_NOT_FOUND` is returned by the `FindFirstFileW` function
// The status `ERROR_FILE_NOT_FOUND` is returned by the `FindFirstFileExW` function
// if no matching files can be found, but not necessarily that the path to find the
// files in does not exist.
//
Expand All @@ -1079,7 +1093,7 @@ pub fn readdir(p: &Path) -> io::Result<ReadDir> {

// Just return the error constructed from the raw OS error if the above is not the case.
//
// Note: `ERROR_PATH_NOT_FOUND` would have been returned by the `FindFirstFileW` function
// Note: `ERROR_PATH_NOT_FOUND` would have been returned by the `FindFirstFileExW` function
// when the path to search in does not exist in the first place.
Err(Error::from_raw_os_error(last_error.code as i32))
}
Expand Down Expand Up @@ -1220,7 +1234,7 @@ fn metadata(path: &Path, reparse: ReparsePoint) -> io::Result<FileAttr> {
opts.custom_flags(c::FILE_FLAG_BACKUP_SEMANTICS | reparse.as_flag());

// Attempt to open the file normally.
// If that fails with `ERROR_SHARING_VIOLATION` then retry using `FindFirstFileW`.
// If that fails with `ERROR_SHARING_VIOLATION` then retry using `FindFirstFileExW`.
// If the fallback fails for any reason we return the original error.
match File::open(path, &opts) {
Ok(file) => file.file_attr(),
Expand All @@ -1237,13 +1251,20 @@ fn metadata(path: &Path, reparse: ReparsePoint) -> io::Result<FileAttr> {
unsafe {
let path = maybe_verbatim(path)?;

// `FindFirstFileW` accepts wildcard file names.
// `FindFirstFileExW` accepts wildcard file names.
// Fortunately wildcards are not valid file names and
// `ERROR_SHARING_VIOLATION` means the file exists (but is locked)
// therefore it's safe to assume the file name given does not
// include wildcards.
let mut wfd = mem::zeroed();
let handle = c::FindFirstFileW(path.as_ptr(), &mut wfd);
let mut wfd: c::WIN32_FIND_DATAW = mem::zeroed();
let handle = c::FindFirstFileExW(
path.as_ptr(),
c::FindExInfoBasic,
&mut wfd as *mut _ as _,
c::FindExSearchNameMatch,
ptr::null(),
0,
);

if handle == c::INVALID_HANDLE_VALUE {
// This can fail if the user does not have read access to the
Expand All @@ -1253,7 +1274,7 @@ fn metadata(path: &Path, reparse: ReparsePoint) -> io::Result<FileAttr> {
// We no longer need the find handle.
c::FindClose(handle);

// `FindFirstFileW` reads the cached file information from the
// `FindFirstFileExW` reads the cached file information from the
// directory. The downside is that this metadata may be outdated.
let attrs = FileAttr::from(wfd);
if reparse == ReparsePoint::Follow && attrs.file_type().is_symlink() {
Expand Down
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