1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
use crate::filesystem::primitives::{FollowSymlinks, OpenOptions, OpenOptionsExt};
use windows_sys::Win32::Storage::FileSystem::{
FILE_FLAG_BACKUP_SEMANTICS, FILE_FLAG_OPEN_REPARSE_POINT, FILE_FLAG_WRITE_THROUGH,
FILE_SHARE_DELETE,
};
/// Adjust an `OpenOptions` after all the flags are set, in preparation
/// for the to call a Windows API `open` function. Also return a bool
/// indicating that the `trunc` flag was requested but could not be set,
/// so the file should be truncated manually after opening.
pub(in super::super) fn prepare_open_options_for_open(opts: &mut OpenOptions) -> bool {
let mut trunc = opts.truncate;
let mut manually_trunc = false;
let mut custom_flags = match opts.follow {
FollowSymlinks::Yes => opts.ext.custom_flags,
FollowSymlinks::No => {
if trunc && !opts.create_new && !opts.append && opts.write {
// On Windows, truncating overwrites a symlink with a
// non-symlink.
manually_trunc = true;
trunc = false;
}
opts.ext.custom_flags | FILE_FLAG_OPEN_REPARSE_POINT
}
};
let mut share_mode = opts.ext.share_mode;
if opts.maybe_dir {
custom_flags |= FILE_FLAG_BACKUP_SEMANTICS;
// Only allow `FILE_SHARE_READ` and `FILE_SHARE_WRITE`; this mirrors
// the values in `dir_options()` and is done to prevent directories
// from being deleted or renamed underneath cap-std's sandboxed path
// lookups on Windows.
share_mode &= !FILE_SHARE_DELETE;
}
// This matches system-interface's `set_fd_flags` interpretation of these
// flags on Windows.
if opts.sync || opts.dsync {
custom_flags |= FILE_FLAG_WRITE_THROUGH;
}
opts.truncate(trunc)
.share_mode(share_mode)
.custom_flags(custom_flags);
manually_trunc
}