ZacharyZhang-NY
b7fca0146d
ElyDoc, ElyTable, ElyShow (LibreOfficeKit), ElyPDF (MuPDF), ElyTree (Git), ElyMark (Milkdown and CodeMirror in CEF). ElyMail and ElyAgent follow.
96 lines
2.9 KiB
Rust
96 lines
2.9 KiB
Rust
//! Renames that never replace a file (MARK-01).
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use std::{io, path::Path};
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/// Renames `from` to `to`; an existing `to` fails, atomically.
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#[cfg(target_os = "macos")]
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pub fn rename_new(from: &Path, to: &Path) -> io::Result<()> {
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let (from, to) = (c_path(from)?, c_path(to)?);
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// SAFETY: both are NUL-terminated paths that outlive the call.
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let done = unsafe { libc::renamex_np(from.as_ptr(), to.as_ptr(), libc::RENAME_EXCL) };
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if done == 0 {
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Ok(())
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} else {
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Err(io::Error::last_os_error())
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}
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}
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#[cfg(target_os = "linux")]
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pub fn rename_new(from: &Path, to: &Path) -> io::Result<()> {
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let (from, to) = (c_path(from)?, c_path(to)?);
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// SAFETY: both are NUL-terminated paths that outlive the call.
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let done = unsafe {
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libc::renameat2(
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libc::AT_FDCWD,
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from.as_ptr(),
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libc::AT_FDCWD,
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to.as_ptr(),
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libc::RENAME_NOREPLACE,
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)
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};
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if done == 0 {
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Ok(())
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} else {
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Err(io::Error::last_os_error())
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}
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}
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#[cfg(windows)]
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pub fn rename_new(from: &Path, to: &Path) -> io::Result<()> {
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use std::os::windows::ffi::OsStrExt as _;
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let wide = |path: &Path| {
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path.as_os_str()
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.encode_wide()
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.chain([0])
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.collect::<Vec<u16>>()
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};
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let (from, to) = (wide(from), wide(to));
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// SAFETY: both are NUL-terminated wide paths; no flag replaces.
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let done = unsafe {
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windows_sys::Win32::Storage::FileSystem::MoveFileExW(from.as_ptr(), to.as_ptr(), 0)
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};
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if done != 0 {
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Ok(())
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} else {
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Err(io::Error::last_os_error())
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}
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}
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#[cfg(not(any(target_os = "macos", target_os = "linux", windows)))]
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pub fn rename_new(_: &Path, _: &Path) -> io::Result<()> {
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Err(io::Error::new(
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io::ErrorKind::Unsupported,
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"renaming is not built for this platform",
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))
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}
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#[cfg(unix)]
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fn c_path(path: &Path) -> io::Result<std::ffi::CString> {
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use std::os::unix::ffi::OsStrExt as _;
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std::ffi::CString::new(path.as_os_str().as_bytes())
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.map_err(|_| io::Error::new(io::ErrorKind::InvalidInput, "a path holds NUL"))
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}
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#[cfg(test)]
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mod tests {
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use super::rename_new;
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#[test]
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fn a_rename_moves_and_never_replaces() {
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let dir = tempfile::tempdir().expect("a temp dir");
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let (a, b, c) = (
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dir.path().join("a.md"),
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dir.path().join("b.md"),
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dir.path().join("c.md"),
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);
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std::fs::write(&a, "a").expect("writes");
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std::fs::write(&b, "b").expect("writes");
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let error = rename_new(&a, &b).expect_err("b exists");
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assert_eq!(error.kind(), std::io::ErrorKind::AlreadyExists);
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assert_eq!(std::fs::read_to_string(&b).expect("reads"), "b");
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rename_new(&a, &c).expect("renames");
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assert!(!a.exists());
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assert_eq!(std::fs::read_to_string(&c).expect("reads"), "a");
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}
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}
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