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use std::{
borrow::Cow,
ffi::{OsStr, OsString},
io,
path::{Component, Path, PathBuf, MAIN_SEPARATOR_STR},
};
use crate::ParseDot;
impl ParseDot for Path {
#[inline]
fn parse_dot(&self) -> io::Result<Cow<'_, Path>> {
match self.components().next() {
Some(Component::CurDir | Component::ParentDir) => {
let cwd = get_cwd!();
Ok(self.parse_dot_from(cwd))
},
// the cwd is only used when the path starts with a single dot or double dots, so an empty path is enough here
_ => Ok(self.parse_dot_from(Path::new(""))),
}
}
fn parse_dot_from(&self, cwd: impl AsRef<Path>) -> Cow<'_, Path> {
let main_separator = OsStr::new(MAIN_SEPARATOR_STR);
let mut iter = self.components();
let mut has_dots = false;
if let Some(first_component) = iter.next() {
let mut tokens = Vec::new();
let first_is_root = match first_component {
Component::RootDir => {
tokens.push(main_separator);
true
},
Component::CurDir => {
has_dots = true;
let cwd = cwd.as_ref();
for token in cwd.iter() {
tokens.push(token);
}
!tokens.is_empty() && tokens[0] == main_separator
},
Component::ParentDir => {
has_dots = true;
let cwd = cwd.as_ref();
match cwd.parent() {
Some(cwd_parent) => {
for token in cwd_parent.iter() {
tokens.push(token);
}
!tokens.is_empty() && tokens[0] == main_separator
},
None => {
// don't care about `cwd` is "//" or "///"
if cwd == main_separator {
tokens.push(main_separator);
true
} else {
false
}
},
}
},
_ => {
tokens.push(first_component.as_os_str());
false
},
};
for component in iter {
match component {
Component::CurDir => {
// may be unreachable
has_dots = true;
},
Component::ParentDir => {
let tokens_length = tokens.len();
if tokens_length > 0 && (tokens_length != 1 || !first_is_root) {
tokens.pop();
}
has_dots = true;
},
_ => {
tokens.push(component.as_os_str());
},
}
}
// all tokens can be removed by double dots (e.g. `a/../..`), and in this case the result is an empty path
if tokens.is_empty() {
return Cow::from(PathBuf::new());
}
let tokens_length = tokens.len();
let mut size = tokens.iter().fold(tokens_length - 1, |acc, &x| acc + x.len());
if first_is_root && tokens_length > 1 {
size -= 1;
}
if has_dots || size != self.as_os_str().len() {
let mut path_string = OsString::with_capacity(size);
let mut iter = tokens.iter();
path_string.push(iter.next().unwrap());
if tokens_length > 1 {
if !first_is_root {
path_string.push(main_separator);
}
for token in iter.take(tokens_length - 2) {
path_string.push(token);
path_string.push(main_separator);
}
path_string.push(tokens[tokens_length - 1]);
}
let path_buf = PathBuf::from(path_string);
Cow::from(path_buf)
} else {
Cow::from(self)
}
} else {
Cow::from(self)
}
}
}