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Windows: Use FILE_ALLOCATION_INFO for truncation #134722

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Merged
merged 1 commit into from
Dec 25, 2024
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Windows: Use FILE_ALLOCATION_INFO for truncation #134722

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28 changes: 20 additions & 8 deletions library/std/src/sys/pal/windows/fs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -316,19 +316,31 @@ impl File {
&& api::get_last_error() == WinError::ALREADY_EXISTS
{
unsafe {
// This originally used `FileAllocationInfo` instead of
// `FileEndOfFileInfo` but that wasn't supported by WINE.
// It's arguable which fits the semantics of `OpenOptions`
// better so let's just use the more widely supported method.
let eof = c::FILE_END_OF_FILE_INFO { EndOfFile: 0 };
// This first tries `FileAllocationInfo` but falls back to
// `FileEndOfFileInfo` in order to support WINE.
// If WINE gains support for FileAllocationInfo, we should
// remove the fallback.
let alloc = c::FILE_ALLOCATION_INFO { AllocationSize: 0 };
let result = c::SetFileInformationByHandle(
handle.as_raw_handle(),
c::FileEndOfFileInfo,
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Suggested change
c::FileEndOfFileInfo,
c::FileAllocationInfo,

Doesn't this need to be changed to FileAllocationInfo?

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@ChrisDenton ChrisDenton Dec 27, 2024 •
edited
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Oh, huh. I fixed that locally but somehow forgot to push. Fortunately their associated values are the same size (and if they weren't then it'd return an error).

(&raw const eof).cast::<c_void>(),
mem::size_of::<c::FILE_END_OF_FILE_INFO>() as u32,
(&raw const alloc).cast::<c_void>(),
mem::size_of::<c::FILE_ALLOCATION_INFO>() as u32,
);
if result == 0 {
return Err(io::Error::last_os_error());
if api::get_last_error().code != 0 {
panic!("FILE_ALLOCATION_INFO failed!!!");
}
let eof = c::FILE_END_OF_FILE_INFO { EndOfFile: 0 };
let result = c::SetFileInformationByHandle(
handle.as_raw_handle(),
c::FileEndOfFileInfo,
(&raw const eof).cast::<c_void>(),
mem::size_of::<c::FILE_END_OF_FILE_INFO>() as u32,
);
if result == 0 {
return Err(io::Error::last_os_error());
}
}
}
}
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