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use std::ffi::OsStr;
use std::fs::{File, OpenOptions};
use std::os::windows::ffi::OsStrExt;
use std::os::windows::fs::OpenOptionsExt;
use std::os::windows::io::{AsRawHandle, FromRawHandle, RawHandle};
use std::path::Path;
use std::{io, iter};
use windows_sys::Win32::Foundation::{HANDLE, INVALID_HANDLE_VALUE};
use windows_sys::Win32::Storage::FileSystem::{
MoveFileExW, ReOpenFile, SetFileAttributesW, FILE_ATTRIBUTE_NORMAL, FILE_ATTRIBUTE_TEMPORARY,
FILE_FLAG_DELETE_ON_CLOSE, FILE_GENERIC_READ, FILE_GENERIC_WRITE, FILE_SHARE_DELETE,
FILE_SHARE_READ, FILE_SHARE_WRITE, MOVEFILE_REPLACE_EXISTING,
};
use crate::util;
fn to_utf16(s: &Path) -> Vec<u16> {
s.as_os_str().encode_wide().chain(iter::once(0)).collect()
}
fn not_supported<T>(msg: &str) -> io::Result<T> {
Err(io::Error::new(io::ErrorKind::Other, msg))
}
pub fn create_named(
path: &Path,
open_options: &mut OpenOptions,
permissions: Option<&std::fs::Permissions>,
) -> io::Result<File> {
if permissions.map_or(false, |p| p.readonly()) {
return not_supported("changing permissions is not supported on this platform");
}
open_options
.create_new(true)
.read(true)
.write(true)
.custom_flags(FILE_ATTRIBUTE_TEMPORARY)
.open(path)
}
pub fn create(dir: &Path) -> io::Result<File> {
util::create_helper(
dir,
OsStr::new(".tmp"),
OsStr::new(""),
crate::NUM_RAND_CHARS,
None,
|path, _permissions| {
OpenOptions::new()
.create_new(true)
.read(true)
.write(true)
.share_mode(0)
.custom_flags(FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_DELETE_ON_CLOSE)
.open(path)
},
)
}
pub fn reopen(file: &File, _path: &Path) -> io::Result<File> {
let handle = file.as_raw_handle();
unsafe {
let handle = ReOpenFile(
handle as HANDLE,
FILE_GENERIC_READ | FILE_GENERIC_WRITE,
FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
0,
);
if handle == INVALID_HANDLE_VALUE {
Err(io::Error::last_os_error())
} else {
Ok(FromRawHandle::from_raw_handle(handle as RawHandle))
}
}
}
pub fn keep(path: &Path) -> io::Result<()> {
unsafe {
let path_w = to_utf16(path);
if SetFileAttributesW(path_w.as_ptr(), FILE_ATTRIBUTE_NORMAL) == 0 {
Err(io::Error::last_os_error())
} else {
Ok(())
}
}
}
pub fn persist(old_path: &Path, new_path: &Path, overwrite: bool) -> io::Result<()> {
unsafe {
let old_path_w = to_utf16(old_path);
let new_path_w = to_utf16(new_path);
// Don't succeed if this fails. We don't want to claim to have successfully persisted a file
// still marked as temporary because this file won't have the same consistency guarantees.
if SetFileAttributesW(old_path_w.as_ptr(), FILE_ATTRIBUTE_NORMAL) == 0 {
return Err(io::Error::last_os_error());
}
let mut flags = 0;
if overwrite {
flags |= MOVEFILE_REPLACE_EXISTING;
}
if MoveFileExW(old_path_w.as_ptr(), new_path_w.as_ptr(), flags) == 0 {
let e = io::Error::last_os_error();
// If this fails, the temporary file is now un-hidden and no longer marked temporary
// (slightly less efficient) but it will still work.
let _ = SetFileAttributesW(old_path_w.as_ptr(), FILE_ATTRIBUTE_TEMPORARY);
Err(e)
} else {
Ok(())
}
}
}