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dirstate-tree: Make `DirstateMap` borrow from a bytes buffer...
dirstate-tree: Make `DirstateMap` borrow from a bytes buffer … that has the contents of the `.hg/dirstate` file. This only applies to the tree-based flavor of `DirstateMap`. For now only the entire `&[u8]` slice is stored, so this is not useful yet. Adding a lifetime parameter to the `DirstateMap` struct (in hg-core) makes Python bindings non-trivial because we keep that struct in a Python object that has a dynamic lifetime tied to Python’s reference-counting and GC. As long as we keep the `PyBytes` that owns the borrowed bytes buffer next to the borrowing struct, the buffer will live long enough for the borrows to stay valid. However this relationship cannot be expressed in safe Rust code in a way that would statisfy they borrow-checker. We use `unsafe` code to erase that lifetime parameter, and encapsulate it in a safe abstraction similar to the owning-ref crate: https://docs.rs/owning_ref/ Differential Revision: https://phab.mercurial-scm.org/D10557

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dirs_multiset.rs
422 lines | 13.1 KiB | application/rls-services+xml | RustLexer
// dirs_multiset.rs
//
// Copyright 2019 Raphaël Gomès <rgomes@octobus.net>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.
//! A multiset of directory names.
//!
//! Used to counts the references to directories in a manifest or dirstate.
use crate::{
dirstate::EntryState,
utils::{
files,
hg_path::{HgPath, HgPathBuf, HgPathError},
},
DirstateEntry, DirstateMapError, FastHashMap,
};
use std::collections::{hash_map, hash_map::Entry, HashMap, HashSet};
// could be encapsulated if we care API stability more seriously
pub type DirsMultisetIter<'a> = hash_map::Keys<'a, HgPathBuf, u32>;
#[derive(PartialEq, Debug)]
pub struct DirsMultiset {
inner: FastHashMap<HgPathBuf, u32>,
}
impl DirsMultiset {
/// Initializes the multiset from a dirstate.
///
/// If `skip_state` is provided, skips dirstate entries with equal state.
pub fn from_dirstate<'a>(
dirstate: impl IntoIterator<Item = (&'a HgPathBuf, &'a DirstateEntry)>,
skip_state: Option<EntryState>,
) -> Result<Self, DirstateMapError> {
let mut multiset = DirsMultiset {
inner: FastHashMap::default(),
};
for (filename, DirstateEntry { state, .. }) in dirstate {
// This `if` is optimized out of the loop
if let Some(skip) = skip_state {
if skip != *state {
multiset.add_path(filename)?;
}
} else {
multiset.add_path(filename)?;
}
}
Ok(multiset)
}
/// Initializes the multiset from a manifest.
pub fn from_manifest(
manifest: &[impl AsRef<HgPath>],
) -> Result<Self, DirstateMapError> {
let mut multiset = DirsMultiset {
inner: FastHashMap::default(),
};
for filename in manifest {
multiset.add_path(filename.as_ref())?;
}
Ok(multiset)
}
/// Increases the count of deepest directory contained in the path.
///
/// If the directory is not yet in the map, adds its parents.
pub fn add_path(
&mut self,
path: impl AsRef<HgPath>,
) -> Result<(), DirstateMapError> {
for subpath in files::find_dirs(path.as_ref()) {
if subpath.as_bytes().last() == Some(&b'/') {
// TODO Remove this once PathAuditor is certified
// as the only entrypoint for path data
let second_slash_index = subpath.len() - 1;
return Err(DirstateMapError::InvalidPath(
HgPathError::ConsecutiveSlashes {
bytes: path.as_ref().as_bytes().to_owned(),
second_slash_index,
},
));
}
if let Some(val) = self.inner.get_mut(subpath) {
*val += 1;
break;
}
self.inner.insert(subpath.to_owned(), 1);
}
Ok(())
}
/// Decreases the count of deepest directory contained in the path.
///
/// If it is the only reference, decreases all parents until one is
/// removed.
/// If the directory is not in the map, something horrible has happened.
pub fn delete_path(
&mut self,
path: impl AsRef<HgPath>,
) -> Result<(), DirstateMapError> {
for subpath in files::find_dirs(path.as_ref()) {
match self.inner.entry(subpath.to_owned()) {
Entry::Occupied(mut entry) => {
let val = *entry.get();
if val > 1 {
entry.insert(val - 1);
break;
}
entry.remove();
}
Entry::Vacant(_) => {
return Err(DirstateMapError::PathNotFound(
path.as_ref().to_owned(),
))
}
};
}
Ok(())
}
pub fn contains(&self, key: impl AsRef<HgPath>) -> bool {
self.inner.contains_key(key.as_ref())
}
pub fn iter(&self) -> DirsMultisetIter {
self.inner.keys()
}
pub fn len(&self) -> usize {
self.inner.len()
}
pub fn is_empty(&self) -> bool {
self.len() == 0
}
}
/// This is basically a reimplementation of `DirsMultiset` that stores the
/// children instead of just a count of them, plus a small optional
/// optimization to avoid some directories we don't need.
#[derive(PartialEq, Debug)]
pub struct DirsChildrenMultiset<'a> {
inner: FastHashMap<&'a HgPath, HashSet<&'a HgPath>>,
only_include: Option<HashSet<&'a HgPath>>,
}
impl<'a> DirsChildrenMultiset<'a> {
pub fn new(
paths: impl Iterator<Item = &'a HgPathBuf>,
only_include: Option<&'a HashSet<impl AsRef<HgPath> + 'a>>,
) -> Self {
let mut new = Self {
inner: HashMap::default(),
only_include: only_include
.map(|s| s.iter().map(AsRef::as_ref).collect()),
};
for path in paths {
new.add_path(path)
}
new
}
fn add_path(&mut self, path: &'a (impl AsRef<HgPath> + 'a)) {
if path.as_ref().is_empty() {
return;
}
for (directory, basename) in files::find_dirs_with_base(path.as_ref())
{
if !self.is_dir_included(directory) {
continue;
}
self.inner
.entry(directory)
.and_modify(|e| {
e.insert(basename);
})
.or_insert_with(|| {
let mut set = HashSet::new();
set.insert(basename);
set
});
}
}
fn is_dir_included(&self, dir: impl AsRef<HgPath>) -> bool {
match &self.only_include {
None => false,
Some(i) => i.contains(dir.as_ref()),
}
}
pub fn get(
&self,
path: impl AsRef<HgPath>,
) -> Option<&HashSet<&'a HgPath>> {
self.inner.get(path.as_ref())
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::StateMap;
#[test]
fn test_delete_path_path_not_found() {
let manifest: Vec<HgPathBuf> = vec![];
let mut map = DirsMultiset::from_manifest(&manifest).unwrap();
let path = HgPathBuf::from_bytes(b"doesnotexist/");
assert_eq!(
Err(DirstateMapError::PathNotFound(path.to_owned())),
map.delete_path(&path)
);
}
#[test]
fn test_delete_path_empty_path() {
let mut map =
DirsMultiset::from_manifest(&vec![HgPathBuf::new()]).unwrap();
let path = HgPath::new(b"");
assert_eq!(Ok(()), map.delete_path(path));
assert_eq!(
Err(DirstateMapError::PathNotFound(path.to_owned())),
map.delete_path(path)
);
}
#[test]
fn test_delete_path_successful() {
let mut map = DirsMultiset {
inner: [("", 5), ("a", 3), ("a/b", 2), ("a/c", 1)]
.iter()
.map(|(k, v)| (HgPathBuf::from_bytes(k.as_bytes()), *v))
.collect(),
};
assert_eq!(Ok(()), map.delete_path(HgPath::new(b"a/b/")));
eprintln!("{:?}", map);
assert_eq!(Ok(()), map.delete_path(HgPath::new(b"a/b/")));
eprintln!("{:?}", map);
assert_eq!(
Err(DirstateMapError::PathNotFound(HgPathBuf::from_bytes(
b"a/b/"
))),
map.delete_path(HgPath::new(b"a/b/"))
);
assert_eq!(2, *map.inner.get(HgPath::new(b"a")).unwrap());
assert_eq!(1, *map.inner.get(HgPath::new(b"a/c")).unwrap());
eprintln!("{:?}", map);
assert_eq!(Ok(()), map.delete_path(HgPath::new(b"a/")));
eprintln!("{:?}", map);
assert_eq!(Ok(()), map.delete_path(HgPath::new(b"a/c/")));
assert_eq!(
Err(DirstateMapError::PathNotFound(HgPathBuf::from_bytes(
b"a/c/"
))),
map.delete_path(HgPath::new(b"a/c/"))
);
}
#[test]
fn test_add_path_empty_path() {
let manifest: Vec<HgPathBuf> = vec![];
let mut map = DirsMultiset::from_manifest(&manifest).unwrap();
let path = HgPath::new(b"");
map.add_path(path).unwrap();
assert_eq!(1, map.len());
}
#[test]
fn test_add_path_successful() {
let manifest: Vec<HgPathBuf> = vec![];
let mut map = DirsMultiset::from_manifest(&manifest).unwrap();
map.add_path(HgPath::new(b"a/")).unwrap();
assert_eq!(1, *map.inner.get(HgPath::new(b"a")).unwrap());
assert_eq!(1, *map.inner.get(HgPath::new(b"")).unwrap());
assert_eq!(2, map.len());
// Non directory should be ignored
map.add_path(HgPath::new(b"a")).unwrap();
assert_eq!(1, *map.inner.get(HgPath::new(b"a")).unwrap());
assert_eq!(2, map.len());
// Non directory will still add its base
map.add_path(HgPath::new(b"a/b")).unwrap();
assert_eq!(2, *map.inner.get(HgPath::new(b"a")).unwrap());
assert_eq!(2, map.len());
// Duplicate path works
map.add_path(HgPath::new(b"a/")).unwrap();
assert_eq!(3, *map.inner.get(HgPath::new(b"a")).unwrap());
// Nested dir adds to its base
map.add_path(HgPath::new(b"a/b/")).unwrap();
assert_eq!(4, *map.inner.get(HgPath::new(b"a")).unwrap());
assert_eq!(1, *map.inner.get(HgPath::new(b"a/b")).unwrap());
// but not its base's base, because it already existed
map.add_path(HgPath::new(b"a/b/c/")).unwrap();
assert_eq!(4, *map.inner.get(HgPath::new(b"a")).unwrap());
assert_eq!(2, *map.inner.get(HgPath::new(b"a/b")).unwrap());
map.add_path(HgPath::new(b"a/c/")).unwrap();
assert_eq!(1, *map.inner.get(HgPath::new(b"a/c")).unwrap());
let expected = DirsMultiset {
inner: [("", 2), ("a", 5), ("a/b", 2), ("a/b/c", 1), ("a/c", 1)]
.iter()
.map(|(k, v)| (HgPathBuf::from_bytes(k.as_bytes()), *v))
.collect(),
};
assert_eq!(map, expected);
}
#[test]
fn test_dirsmultiset_new_empty() {
let manifest: Vec<HgPathBuf> = vec![];
let new = DirsMultiset::from_manifest(&manifest).unwrap();
let expected = DirsMultiset {
inner: FastHashMap::default(),
};
assert_eq!(expected, new);
let new =
DirsMultiset::from_dirstate(&StateMap::default(), None).unwrap();
let expected = DirsMultiset {
inner: FastHashMap::default(),
};
assert_eq!(expected, new);
}
#[test]
fn test_dirsmultiset_new_no_skip() {
let input_vec: Vec<HgPathBuf> = ["a/", "b/", "a/c", "a/d/"]
.iter()
.map(|e| HgPathBuf::from_bytes(e.as_bytes()))
.collect();
let expected_inner = [("", 2), ("a", 3), ("b", 1), ("a/d", 1)]
.iter()
.map(|(k, v)| (HgPathBuf::from_bytes(k.as_bytes()), *v))
.collect();
let new = DirsMultiset::from_manifest(&input_vec).unwrap();
let expected = DirsMultiset {
inner: expected_inner,
};
assert_eq!(expected, new);
let input_map: HashMap<_, _> = ["b/x", "a/c", "a/d/x"]
.iter()
.map(|f| {
(
HgPathBuf::from_bytes(f.as_bytes()),
DirstateEntry {
state: EntryState::Normal,
mode: 0,
mtime: 0,
size: 0,
},
)
})
.collect();
let expected_inner = [("", 2), ("a", 2), ("b", 1), ("a/d", 1)]
.iter()
.map(|(k, v)| (HgPathBuf::from_bytes(k.as_bytes()), *v))
.collect();
let new = DirsMultiset::from_dirstate(&input_map, None).unwrap();
let expected = DirsMultiset {
inner: expected_inner,
};
assert_eq!(expected, new);
}
#[test]
fn test_dirsmultiset_new_skip() {
let input_map: HashMap<_, _> = [
("a/", EntryState::Normal),
("a/b", EntryState::Normal),
("a/c", EntryState::Removed),
("a/d", EntryState::Merged),
]
.iter()
.map(|(f, state)| {
(
HgPathBuf::from_bytes(f.as_bytes()),
DirstateEntry {
state: *state,
mode: 0,
mtime: 0,
size: 0,
},
)
})
.collect();
// "a" incremented with "a/c" and "a/d/"
let expected_inner = [("", 1), ("a", 2)]
.iter()
.map(|(k, v)| (HgPathBuf::from_bytes(k.as_bytes()), *v))
.collect();
let new =
DirsMultiset::from_dirstate(&input_map, Some(EntryState::Normal))
.unwrap();
let expected = DirsMultiset {
inner: expected_inner,
};
assert_eq!(expected, new);
}
}