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#[cfg(not(target_os = "fuchsia"))]
use crate::backend::fd::AsFd;
#[cfg(feature = "fs")]
use crate::path;
#[cfg(any(feature = "fs", not(target_os = "fuchsia")))]
use crate::{backend, io};
#[cfg(all(feature = "alloc", feature = "fs"))]
use {
crate::ffi::{CStr, CString},
crate::path::SMALL_PATH_BUFFER_SIZE,
alloc::vec::Vec,
};
/// `chdir(path)`—Change the current working directory.
///
/// # References
/// - [POSIX]
/// - [Linux]
///
#[inline]
#[cfg(feature = "fs")]
#[cfg_attr(doc_cfg, doc(cfg(feature = "fs")))]
pub fn chdir<P: path::Arg>(path: P) -> io::Result<()> {
path.into_with_c_str(backend::process::syscalls::chdir)
}
/// `fchdir(fd)`—Change the current working directory.
///
/// # References
/// - [POSIX]
/// - [Linux]
///
#[cfg(not(target_os = "fuchsia"))]
#[inline]
pub fn fchdir<Fd: AsFd>(fd: Fd) -> io::Result<()> {
backend::process::syscalls::fchdir(fd.as_fd())
}
/// `getCWD`—Return the current working directory.
///
/// If `reuse` already has available capacity, reuse it if possible.
///
/// # References
/// - [POSIX]
/// - [Linux]
///
#[cfg(all(feature = "alloc", feature = "fs"))]
#[cfg(not(target_os = "wasi"))]
#[cfg_attr(doc_cfg, doc(cfg(feature = "fs")))]
#[inline]
pub fn getcwd<B: Into<Vec<u8>>>(reuse: B) -> io::Result<CString> {
_getcwd(reuse.into())
}
#[cfg(all(feature = "alloc", feature = "fs"))]
#[allow(unsafe_code)]
fn _getcwd(mut buffer: Vec<u8>) -> io::Result<CString> {
buffer.clear();
buffer.reserve(SMALL_PATH_BUFFER_SIZE);
loop {
match backend::process::syscalls::getcwd(buffer.spare_capacity_mut()) {
Err(io::Errno::RANGE) => {
// Use `Vec` reallocation strategy to grow capacity
// exponentially.
buffer.reserve(buffer.capacity() + 1);
}
Ok(_) => {
// SAFETY:
// - "These functions return a null-terminated string"
// - [POSIX definition 3.375: String]: "A contiguous sequence
// of bytes terminated by and including the first null byte."
//
// Thus, there will be a single NUL byte at the end of the
// string.
//
// [POSIX definition 3.375: String]: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_375
unsafe {
buffer.set_len(
CStr::from_ptr(buffer.as_ptr().cast())
.to_bytes_with_nul()
.len(),
);
return Ok(CString::from_vec_with_nul_unchecked(buffer));
}
}
Err(errno) => return Err(errno),
}
}
}