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use std::env;
use std::ffi::OsStr;
use std::fs::{self, File, OpenOptions};
use std::io;
cfg_if::cfg_if! {
if #[cfg(not(target_os = "wasi"))] {
use std::os::unix::fs::MetadataExt;
} else {
#[cfg(feature = "nightly")]
use std::os::wasi::fs::MetadataExt;
}
}
use crate::util;
use std::path::Path;
#[cfg(not(target_os = "redox"))]
use {
rustix::fs::{rename, unlink},
std::fs::hard_link,
};
pub fn create_named(
path: &Path,
open_options: &mut OpenOptions,
#[cfg_attr(target_os = "wasi", allow(unused))] permissions: Option<&std::fs::Permissions>,
) -> io::Result<File> {
open_options.read(true).write(true).create_new(true);
#[cfg(not(target_os = "wasi"))]
{
use std::os::unix::fs::{OpenOptionsExt, PermissionsExt};
open_options.mode(permissions.map(|p| p.mode()).unwrap_or(0o600));
}
open_options.open(path)
}
fn create_unlinked(path: &Path) -> io::Result<File> {
let tmp;
// shadow this to decrease the lifetime. It can't live longer than `tmp`.
let mut path = path;
if !path.is_absolute() {
let cur_dir = env::current_dir()?;
tmp = cur_dir.join(path);
path = &tmp;
}
let f = create_named(path, &mut OpenOptions::new(), None)?;
// don't care whether the path has already been unlinked,
// but perhaps there are some IO error conditions we should send up?
let _ = fs::remove_file(path);
Ok(f)
}
#[cfg(target_os = "linux")]
pub fn create(dir: &Path) -> io::Result<File> {
use rustix::{fs::OFlags, io::Errno};
use std::os::unix::fs::OpenOptionsExt;
OpenOptions::new()
.read(true)
.write(true)
.custom_flags(OFlags::TMPFILE.bits() as i32) // do not mix with `create_new(true)`
.open(dir)
.or_else(|e| {
match Errno::from_io_error(&e) {
// These are the three "not supported" error codes for O_TMPFILE.
Some(Errno::OPNOTSUPP) | Some(Errno::ISDIR) | Some(Errno::NOENT) => {
create_unix(dir)
}
_ => Err(e),
}
})
}
#[cfg(not(target_os = "linux"))]
pub fn create(dir: &Path) -> io::Result<File> {
create_unix(dir)
}
fn create_unix(dir: &Path) -> io::Result<File> {
util::create_helper(
dir,
OsStr::new(".tmp"),
OsStr::new(""),
crate::NUM_RAND_CHARS,
None,
|path, _| create_unlinked(&path),
)
}
#[cfg(any(not(target_os = "wasi"), feature = "nightly"))]
pub fn reopen(file: &File, path: &Path) -> io::Result<File> {
let new_file = OpenOptions::new().read(true).write(true).open(path)?;
let old_meta = file.metadata()?;
let new_meta = new_file.metadata()?;
if old_meta.dev() != new_meta.dev() || old_meta.ino() != new_meta.ino() {
return Err(io::Error::new(
io::ErrorKind::NotFound,
"original tempfile has been replaced",
));
}
Ok(new_file)
}
#[cfg(all(target_os = "wasi", not(feature = "nightly")))]
pub fn reopen(_file: &File, _path: &Path) -> io::Result<File> {
return Err(io::Error::new(
io::ErrorKind::Other,
"this operation is supported on WASI only on nightly Rust (with `nightly` feature enabled)",
));
}
#[cfg(not(target_os = "redox"))]
pub fn persist(old_path: &Path, new_path: &Path, overwrite: bool) -> io::Result<()> {
if overwrite {
rename(old_path, new_path)?;
} else {
// On Linux, use `renameat_with` to avoid overwriting an existing name,
// if the kernel and the filesystem support it.
#[cfg(any(target_os = "android", target_os = "linux"))]
{
use rustix::fs::{renameat_with, RenameFlags, CWD};
use rustix::io::Errno;
use std::sync::atomic::{AtomicBool, Ordering::Relaxed};
static NOSYS: AtomicBool = AtomicBool::new(false);
if !NOSYS.load(Relaxed) {
match renameat_with(CWD, old_path, CWD, new_path, RenameFlags::NOREPLACE) {
Ok(()) => return Ok(()),
Err(Errno::NOSYS) => NOSYS.store(true, Relaxed),
Err(Errno::INVAL) => {}
Err(e) => return Err(e.into()),
}
}
}
// Otherwise use `hard_link` to create the new filesystem name, which
// will fail if the name already exists, and then `unlink` to remove
// the old name.
hard_link(old_path, new_path)?;
// Ignore unlink errors. Can we do better?
let _ = unlink(old_path);
}
Ok(())
}
#[cfg(target_os = "redox")]
pub fn persist(_old_path: &Path, _new_path: &Path, _overwrite: bool) -> io::Result<()> {
// XXX implement when possible
use rustix::io::Errno;
Err(Errno::NOSYS.into())
}
pub fn keep(_: &Path) -> io::Result<()> {
Ok(())
}