//! Contains data structures to deal with Paths in the tvix-castore model.
use std::str::FromStr;
use bstr::ByteSlice;
/// Represents a Path in the castore model.
/// These are always relative, and platform-independent, which distinguishes
/// them from the ones provided in the standard library.
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub struct Path<'a> {
// As node names in the castore model cannot contain slashes,
// we use them as component separators here.
inner: &'a [u8],
}
#[allow(dead_code)]
impl Path<'_> {
pub fn parent(&self) -> Option<Path<'_>> {
let (parent, _file_name) = self.inner.rsplit_once_str(b"/")?;
Some(Self { inner: parent })
}
pub fn join(&self, name: &[u8]) -> Result<PathBuf, std::io::Error> {
if name.contains(&b'/') || name.is_empty() {
return Err(std::io::ErrorKind::InvalidData.into());
}
let mut v = self.inner.to_vec();
if !v.is_empty() {
v.extend_from_slice(b"/");
}
v.extend_from_slice(name);
Ok(PathBuf { inner: v })
}
/// Produces an iterator over the components of the path, which are
/// individual byte slices.
/// In case the path is empty, an empty iterator is returned.
pub fn components(&self) -> impl Iterator<Item = &[u8]> {
let mut iter = self.inner.split_str(&b"/");
// We don't want to return an empty element, consume it if it's the only one.
if self.inner.is_empty() {
let _ = iter.next();
}
iter
}
/// Returns the final component of the Path, if there is one.
pub fn file_name(&self) -> Option<&[u8]> {
self.components().last()
}
pub fn as_slice(&self) -> &[u8] {
self.inner
}
}
/// Represents a owned PathBuf in the castore model.
/// These are always relative, and platform-independent, which distinguishes
/// them from the ones provided in the standard library.
#[derive(Clone, Debug, Default, Eq, Hash, PartialEq)]
pub struct PathBuf {
inner: Vec<u8>,
}
#[allow(dead_code)]
impl PathBuf {
pub fn as_ref(&self) -> Path<'_> {
Path { inner: &self.inner }
}
pub fn parent(&self) -> Option<Path<'_>> {
let (parent, _file_name) = self.inner.rsplit_once_str(b"/")?;
Some(Path { inner: parent })
}
pub fn join(&self, name: &[u8]) -> Result<Self, std::io::Error> {
self.as_ref().join(name)
}
/// Produces an iterator over the components of the path, which are
/// individual byte slices.
pub fn components(&self) -> impl Iterator<Item = &[u8]> {
// TODO(edef): get rid of the duplication
let mut iter = self.inner.split_str(&b"/");
// We don't want to return an empty element, consume it if it's the only one.
if self.inner.is_empty() {
let _ = iter.next();
}
iter
}
/// Returns the final component of the Path, if there is one.
pub fn file_name(&self) -> Option<&[u8]> {
self.components().last()
}
pub fn as_slice(&self) -> &[u8] {
// TODO(edef): get rid of the duplication
self.inner.as_slice()
}
}
impl FromStr for PathBuf {
type Err = std::io::Error;
fn from_str(s: &str) -> Result<PathBuf, Self::Err> {
// Ensure there's no empty components (aka, double forward slashes),
// and all components individually validate.
let p = Path {
inner: s.as_bytes(),
};
for component in p.components() {
if component.is_empty() {
return Err(std::io::ErrorKind::InvalidData.into());
}
}
Ok(PathBuf {
inner: s.to_string().into(),
})
}
}
#[cfg(test)]
mod test {
use super::PathBuf;
use bstr::ByteSlice;
use rstest::rstest;
// TODO: add some manual tests including invalid UTF-8 (hard to express
// with rstest)
#[rstest]
#[case::empty("", 0)]
#[case("a", 1)]
#[case("a/b", 2)]
#[case("a/b/c", 3)]
// add two slightly more cursed variants.
// Technically nothing prevents us from representing this with castore,
// but maybe we want to disallow constructing paths like this as it's a
// bad idea.
#[case::cursed("C:\\a/b", 2)]
#[case::cursed("\\tvix-store", 1)]
pub fn from_str(#[case] s: &str, #[case] num_components: usize) {
let p: PathBuf = s.parse().expect("must parse");
assert_eq!(s.as_bytes(), p.as_slice(), "inner bytes mismatch");
assert_eq!(
num_components,
p.components().count(),
"number of components mismatch"
);
}
#[rstest]
#[case::absolute("/a/b")]
#[case::two_forward_slashes_start("//a/b")]
#[case::two_forward_slashes_middle("a/b//c/d")]
#[case::trailing_slash("a/b/")]
pub fn from_str_fail(#[case] s: &str) {
s.parse::<PathBuf>().expect_err("must fail");
}
#[rstest]
#[case("foo/bar", "foo")]
#[case("foo2/bar2", "foo2")]
#[case("foo/bar/baz", "foo/bar")]
pub fn parent(#[case] p: PathBuf, #[case] exp_parent: PathBuf) {
assert_eq!(Some(exp_parent.as_ref()), p.parent());
// same for Path
let p = p.as_ref();
assert_eq!(Some(exp_parent.as_ref()), p.parent());
}
#[rstest]
#[case::empty("")]
#[case::single("foo")]
pub fn no_parent(#[case] p: PathBuf) {
assert!(p.parent().is_none());
// same for Path
assert!(p.as_ref().parent().is_none());
}
#[rstest]
#[case("a", "b", "a/b")]
#[case("a", "b", "a/b")]
pub fn join(#[case] p: PathBuf, #[case] name: &str, #[case] exp_p: PathBuf) {
assert_eq!(exp_p, p.join(name.as_bytes()).expect("join failed"));
// same for Path
assert_eq!(
exp_p,
p.as_ref().join(name.as_bytes()).expect("join failed")
);
}
#[rstest]
#[case("a", "/")]
#[case("a", "")]
#[case("a", "b/c")]
#[case("", "/")]
#[case("", "")]
#[case("", "b/c")]
pub fn join_fail(#[case] p: PathBuf, #[case] name: &str) {
p.join(name.as_bytes())
.expect_err("join succeeded unexpectedly");
// same for Path
p.as_ref()
.join(name.as_bytes())
.expect_err("join succeeded unexpectedly");
}
#[rstest]
#[case::empty("", vec![])]
#[case("a", vec!["a"])]
#[case("a/b", vec!["a", "b"])]
#[case("a/b/c", vec!["a","b", "c"])]
pub fn components(#[case] p: PathBuf, #[case] exp_components: Vec<&str>) {
assert_eq!(
exp_components,
p.components()
.map(|x| x.to_str().unwrap())
.collect::<Vec<_>>()
);
// same for Path
let p = p.as_ref();
assert_eq!(
exp_components,
p.components()
.map(|x| x.to_str().unwrap())
.collect::<Vec<_>>()
);
}
}
