path_with_basename.rs
172 lines
| 5.3 KiB
| application/rls-services+xml
|
RustLexer
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r47866 | use crate::utils::hg_path::HgPath; | ||
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r47896 | use std::borrow::{Borrow, Cow}; | ||
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r47866 | |||
/// Wraps `HgPath` or `HgPathBuf` to make it behave "as" its last path | ||||
/// component, a.k.a. its base name (as in Python’s `os.path.basename`), but | ||||
/// also allow recovering the full path. | ||||
/// | ||||
/// "Behaving as" means that equality and comparison consider only the base | ||||
/// name, and `std::borrow::Borrow` is implemented to return only the base | ||||
/// name. This allows using the base name as a map key while still being able | ||||
/// to recover the full path, in a single memory allocation. | ||||
#[derive(Debug)] | ||||
pub struct WithBasename<T> { | ||||
full_path: T, | ||||
/// The position after the last slash separator in `full_path`, or `0` | ||||
/// if there is no slash. | ||||
base_name_start: usize, | ||||
} | ||||
impl<T> WithBasename<T> { | ||||
pub fn full_path(&self) -> &T { | ||||
&self.full_path | ||||
} | ||||
} | ||||
impl<T: AsRef<HgPath>> WithBasename<T> { | ||||
pub fn new(full_path: T) -> Self { | ||||
let base_name_start = if let Some(last_slash_position) = full_path | ||||
.as_ref() | ||||
.as_bytes() | ||||
.iter() | ||||
.rposition(|&byte| byte == b'/') | ||||
{ | ||||
last_slash_position + 1 | ||||
} else { | ||||
0 | ||||
}; | ||||
Self { | ||||
base_name_start, | ||||
full_path, | ||||
} | ||||
} | ||||
pub fn base_name(&self) -> &HgPath { | ||||
HgPath::new( | ||||
&self.full_path.as_ref().as_bytes()[self.base_name_start..], | ||||
) | ||||
} | ||||
} | ||||
impl<T: AsRef<HgPath>> Borrow<HgPath> for WithBasename<T> { | ||||
fn borrow(&self) -> &HgPath { | ||||
self.base_name() | ||||
} | ||||
} | ||||
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r47889 | impl<T: AsRef<HgPath>> std::hash::Hash for WithBasename<T> { | ||
fn hash<H: std::hash::Hasher>(&self, hasher: &mut H) { | ||||
self.base_name().hash(hasher) | ||||
} | ||||
} | ||||
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r47866 | impl<T: AsRef<HgPath> + PartialEq> PartialEq for WithBasename<T> { | ||
fn eq(&self, other: &Self) -> bool { | ||||
self.base_name() == other.base_name() | ||||
} | ||||
} | ||||
impl<T: AsRef<HgPath> + Eq> Eq for WithBasename<T> {} | ||||
impl<T: AsRef<HgPath> + PartialOrd> PartialOrd for WithBasename<T> { | ||||
fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> { | ||||
self.base_name().partial_cmp(other.base_name()) | ||||
} | ||||
} | ||||
impl<T: AsRef<HgPath> + Ord> Ord for WithBasename<T> { | ||||
fn cmp(&self, other: &Self) -> std::cmp::Ordering { | ||||
self.base_name().cmp(other.base_name()) | ||||
} | ||||
} | ||||
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r47896 | impl<'a> WithBasename<&'a HgPath> { | ||
pub fn to_cow_borrowed(self) -> WithBasename<Cow<'a, HgPath>> { | ||||
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r47866 | WithBasename { | ||
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r47896 | full_path: Cow::Borrowed(self.full_path), | ||
base_name_start: self.base_name_start, | ||||
} | ||||
} | ||||
pub fn to_cow_owned<'b>(self) -> WithBasename<Cow<'b, HgPath>> { | ||||
WithBasename { | ||||
full_path: Cow::Owned(self.full_path.to_owned()), | ||||
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r47866 | base_name_start: self.base_name_start, | ||
} | ||||
} | ||||
} | ||||
impl<'a> WithBasename<&'a HgPath> { | ||||
/// Returns an iterator of `WithBasename<&HgPath>` for the ancestor | ||||
/// directory paths of the given `path`, as well as `path` itself. | ||||
/// | ||||
/// For example, the full paths of inclusive ancestors of "a/b/c" are "a", | ||||
/// "a/b", and "a/b/c" in that order. | ||||
pub fn inclusive_ancestors_of( | ||||
path: &'a HgPath, | ||||
) -> impl Iterator<Item = WithBasename<&'a HgPath>> { | ||||
let mut slash_positions = | ||||
path.as_bytes().iter().enumerate().filter_map(|(i, &byte)| { | ||||
if byte == b'/' { | ||||
Some(i) | ||||
} else { | ||||
None | ||||
} | ||||
}); | ||||
let mut opt_next_component_start = Some(0); | ||||
std::iter::from_fn(move || { | ||||
opt_next_component_start.take().map(|next_component_start| { | ||||
if let Some(slash_pos) = slash_positions.next() { | ||||
opt_next_component_start = Some(slash_pos + 1); | ||||
Self { | ||||
full_path: HgPath::new(&path.as_bytes()[..slash_pos]), | ||||
base_name_start: next_component_start, | ||||
} | ||||
} else { | ||||
// Not setting `opt_next_component_start` here: there will | ||||
// be no iteration after this one because `.take()` set it | ||||
// to `None`. | ||||
Self { | ||||
full_path: path, | ||||
base_name_start: next_component_start, | ||||
} | ||||
} | ||||
}) | ||||
}) | ||||
} | ||||
} | ||||
#[test] | ||||
fn test() { | ||||
let a = WithBasename::new(HgPath::new("a").to_owned()); | ||||
assert_eq!(&**a.full_path(), HgPath::new(b"a")); | ||||
assert_eq!(a.base_name(), HgPath::new(b"a")); | ||||
let cba = WithBasename::new(HgPath::new("c/b/a").to_owned()); | ||||
assert_eq!(&**cba.full_path(), HgPath::new(b"c/b/a")); | ||||
assert_eq!(cba.base_name(), HgPath::new(b"a")); | ||||
assert_eq!(a, cba); | ||||
let borrowed: &HgPath = cba.borrow(); | ||||
assert_eq!(borrowed, HgPath::new("a")); | ||||
} | ||||
#[test] | ||||
fn test_inclusive_ancestors() { | ||||
let mut iter = WithBasename::inclusive_ancestors_of(HgPath::new("a/bb/c")); | ||||
let next = iter.next().unwrap(); | ||||
assert_eq!(*next.full_path(), HgPath::new("a")); | ||||
assert_eq!(next.base_name(), HgPath::new("a")); | ||||
let next = iter.next().unwrap(); | ||||
assert_eq!(*next.full_path(), HgPath::new("a/bb")); | ||||
assert_eq!(next.base_name(), HgPath::new("bb")); | ||||
let next = iter.next().unwrap(); | ||||
assert_eq!(*next.full_path(), HgPath::new("a/bb/c")); | ||||
assert_eq!(next.base_name(), HgPath::new("c")); | ||||
assert!(iter.next().is_none()); | ||||
} | ||||