rust/hg-core/src/dirstate/dirs_multiset.rs

rust: bump to memmap2 0.5.3, micro-timer 0.4.0, and crossbeam-channel 0.5.0

The merge in 12adf8c695ed had conflicts in rust/Cargo.lock and
rust/hg-core/Cargo.toml . Let's ignore rust/Cargo.lock - it is regenerated.

For rust/hg-core/Cargo.toml, stable had dd6b67d5c256 "rust: fix unsound
`OwningDirstateMap`" which introduced ouroboros (and dropped
stable_deref_trait).

Default had ec8d9b5a5e7c "rust-hg-core: upgrade dependencies" which had a lot
of churn bumping minimum versions - also patch versions. It is indeed a good
idea to bump to *allow* use of latest package. That means that major versions
should be bumped for packages after 1.0, and for packages below 1.0 minor
versions should be bumped too. But it doesn't work to try enforce a policy of
using latest patch by bumping versions at arbitrary times.

For good or bad, the merge doesn't seem to have resolved the conflicts
correctly, and many of the minor "upgrade dependencies" were lost again.

Unfortunately, it also lost the bump of memmap2 to 0.5.3, which is needed for
Fedora packaging where 0.4 isn't available. Same with micro-timer bump to 0.4
(which already is used in rhg). crossbeam-channel bump was also lost.

This change fixes that regression by redoing these "important" lines of the
merge "correctly".

I propose this for stable, even though dependency changes on stable branches
are annoying.

// dirs_multiset.rs
//
// Copyright 2019 Raphaël Gomès <[e-mail]>
//
// 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_tree::on_disk::DirstateV2ParseError;
use crate::{
    utils::{
        files,
        hg_path::{HgPath, HgPathBuf, HgPathError},
    },
    DirstateEntry, DirstateError, 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<I, P>(
        dirstate: I,
        only_tracked: bool,
    ) -> Result<Self, DirstateError>
    where
        I: IntoIterator<
            Item = Result<(P, DirstateEntry), DirstateV2ParseError>,
        >,
        P: AsRef<HgPath>,
    {
        let mut multiset = DirsMultiset {
            inner: FastHashMap::default(),
        };
        for item in dirstate {
            let (filename, entry) = item?;
            let filename = filename.as_ref();
            // This `if` is optimized out of the loop
            if only_tracked {
                if !entry.removed() {
                    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 crate::EntryState;

    use super::*;

    #[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::<_, HgPathBuf>(
            std::iter::empty(),
            false,
        )
        .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 = ["b/x", "a/c", "a/d/x"].iter().map(|f| {
            Ok((
                HgPathBuf::from_bytes(f.as_bytes()),
                DirstateEntry::from_v1_data(EntryState::Normal, 0, 0, 0),
            ))
        });
        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, false).unwrap();
        let expected = DirsMultiset {
            inner: expected_inner,
        };
        assert_eq!(expected, new);
    }

    #[test]
    fn test_dirsmultiset_new_skip() {
        let input_map = [
            ("a/", EntryState::Normal),
            ("a/b", EntryState::Normal),
            ("a/c", EntryState::Removed),
            ("a/d", EntryState::Merged),
        ]
        .iter()
        .map(|(f, state)| {
            Ok((
                HgPathBuf::from_bytes(f.as_bytes()),
                DirstateEntry::from_v1_data(*state, 0, 0, 0),
            ))
        });

        // "a" incremented with "a/c" and "a/d/"
        let expected_inner = [("", 1), ("a", 3)]
            .iter()
            .map(|(k, v)| (HgPathBuf::from_bytes(k.as_bytes()), *v))
            .collect();

        let new = DirsMultiset::from_dirstate(input_map, true).unwrap();
        let expected = DirsMultiset {
            inner: expected_inner,
        };
        assert_eq!(expected, new);
    }
}