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Rollup merge of #101260 - ChrisDenton:attribute-tag, r=thomcc

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Use `FILE_ATTRIBUTE_TAG_INFO` to get reparse tag

I've been looking at this code recently and it just occurred to me we don't actually use the full reparse data at this point, only the tag. [`GetFileInformationByHandleEx`](https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-getfileinformationbyhandleex) can do exactly that by filling a [`FILE_ATTRIBUTE_TAG_INFO`](https://docs.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-file_attribute_tag_info) struct.

r? ```````@thomcc``````` since you've made changes here recently (which is why I have this code on my mind atm)
This commit is contained in:
Matthias Krüger 2022-09-02 18:22:02 +02:00 • committed by GitHub
commit 1e008fec04
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2 changed files with 24 additions and 8 deletions
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6
library/std/src/sys/windows/c.rs
View file

@ -454,6 +454,12 @@ pub enum FILE_INFO_BY_HANDLE_CLASS {
MaximumFileInfoByHandlesClass,
}
#[repr(C)]
pub struct FILE_ATTRIBUTE_TAG_INFO {
pub FileAttributes: DWORD,
pub ReparseTag: DWORD,
}
#[repr(C)]
pub struct FILE_DISPOSITION_INFO {
pub DeleteFile: BOOLEAN,

26
library/std/src/sys/windows/fs.rs
View file

@ -326,10 +326,15 @@ impl File {
cvt(c::GetFileInformationByHandle(self.handle.as_raw_handle(), &mut info))?;
let mut reparse_tag = 0;
if info.dwFileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
let mut b =
Align8([MaybeUninit::<u8>::uninit(); c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
if let Ok((_, buf)) = self.reparse_point(&mut b) {
reparse_tag = (*buf).ReparseTag;
let mut attr_tag: c::FILE_ATTRIBUTE_TAG_INFO = mem::zeroed();
cvt(c::GetFileInformationByHandleEx(
self.handle.as_raw_handle(),
c::FileAttributeTagInfo,
ptr::addr_of_mut!(attr_tag).cast(),
mem::size_of::<c::FILE_ATTRIBUTE_TAG_INFO>().try_into().unwrap(),
))?;
if attr_tag.FileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
reparse_tag = attr_tag.ReparseTag;
}
}
Ok(FileAttr {
@ -390,10 +395,15 @@ impl File {
attr.file_size = info.AllocationSize as u64;
attr.number_of_links = Some(info.NumberOfLinks);
if attr.file_type().is_reparse_point() {
let mut b =
Align8([MaybeUninit::<u8>::uninit(); c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
if let Ok((_, buf)) = self.reparse_point(&mut b) {
attr.reparse_tag = (*buf).ReparseTag;
let mut attr_tag: c::FILE_ATTRIBUTE_TAG_INFO = mem::zeroed();
cvt(c::GetFileInformationByHandleEx(
self.handle.as_raw_handle(),
c::FileAttributeTagInfo,
ptr::addr_of_mut!(attr_tag).cast(),
mem::size_of::<c::FILE_ATTRIBUTE_TAG_INFO>().try_into().unwrap(),
))?;
if attr_tag.FileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
reparse_tag = attr_tag.ReparseTag;
}
}
Ok(attr)