use crate::fs::{
is_root_dir, open_dir_unchecked, read_dir_unchecked, FollowSymlinks, MaybeOwnedFile, Metadata,
};
use std::fs;
use std::path::{Component, PathBuf};
/// Implementation of `file_path` for directories by opening `..` and searching
/// for a directory among `..`'s children to find its name.
pub(crate) fn file_path_by_searching(file: &fs::File) -> Option<PathBuf> {
// Use the `_noassert` functions because the asserts depend on `file_path`,
// which is what we're implementing here.
let mut base = MaybeOwnedFile::borrowed_noassert(file);
let mut components = Vec::new();
// Iterate with `..` until we reach the root directory.
'next_component: loop {
// Open `..`.
let mut iter =
read_dir_unchecked(&base, Component::ParentDir.as_ref(), FollowSymlinks::No).ok()?;
let metadata = Metadata::from_file(&*base).ok()?;
// Search the children until we find one with matching metadata, and
// then record its name.
while let Some(child) = iter.next() {
let child = child.ok()?;
if child.is_same_file(&metadata).ok()? {
// Found a match. Record the name and continue to the next component.
components.push(child.file_name());
base = MaybeOwnedFile::owned_noassert(
open_dir_unchecked(&base, Component::ParentDir.as_ref()).ok()?,
);
continue 'next_component;
}
}
// We didn't find the directory among its parent's children. If we're at
// the root directory, we're done.
if is_root_dir(&base, &iter).ok()? {
break;
}
// Otherwise, something went wrong and we can't determine the path.
return None;
}
let mut path = PathBuf::new();
path.push(Component::RootDir);
for component in components.iter().rev() {
path.push(component);
}
Some(path)
}