view rust/hg-core/src/dirstate/dirstate_map.rs @ 47347:73ddcedeaadf

dirstate-tree: Change status() results to not borrow DirstateMap

The `status` function takes a `&'tree mut DirstateMap<'on_disk>` parameter.
`'on_disk` borrows a read-only byte buffer with the contents of the
`.hg/dirstate` file. `DirstateMap` internally uses represents file paths as
`std::borrow::Cow<'on_disk, HgPath>`, which borrows the byte buffer when
possible and allocates an owned string if not, such as for files added to the
dirstate after it was loaded from disk.

Previously the return type of of `status` has a `'tree` lifetime, meaning it
could borrow all paths from the `DirstateMap`. With this changeset, that
lifetime is changed to `'on_disk` meaning that only paths from the byte buffer
can be borrowed, and paths allocated by `DirstateMap` must be copied.

Usually most paths are in the byte buffer, and most paths are not part of the
return value of `status`, so the number of extra copies should be small.

This change will enable `status` to mutate the `DirstateMap` after it has
finished constructing its return value. Previously such mutation would be
prevented by possible on-going borrows.

Differential Revision: https://phab.mercurial-scm.org/D10824

// dirstate_map.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.

use crate::dirstate::parsers::Timestamp;
use crate::{
    dirstate::EntryState,
    pack_dirstate, parse_dirstate,
    utils::hg_path::{HgPath, HgPathBuf},
    CopyMap, DirsMultiset, DirstateEntry, DirstateError, DirstateParents,
    StateMap,
};
use micro_timer::timed;
use std::collections::HashSet;
use std::iter::FromIterator;
use std::ops::Deref;

#[derive(Default)]
pub struct DirstateMap {
    state_map: StateMap,
    pub copy_map: CopyMap,
    pub dirs: Option<DirsMultiset>,
    pub all_dirs: Option<DirsMultiset>,
    non_normal_set: Option<HashSet<HgPathBuf>>,
    other_parent_set: Option<HashSet<HgPathBuf>>,
}

/// Should only really be used in python interface code, for clarity
impl Deref for DirstateMap {
    type Target = StateMap;

    fn deref(&self) -> &Self::Target {
        &self.state_map
    }
}

impl FromIterator<(HgPathBuf, DirstateEntry)> for DirstateMap {
    fn from_iter<I: IntoIterator<Item = (HgPathBuf, DirstateEntry)>>(
        iter: I,
    ) -> Self {
        Self {
            state_map: iter.into_iter().collect(),
            ..Self::default()
        }
    }
}

impl DirstateMap {
    pub fn new() -> Self {
        Self::default()
    }

    pub fn clear(&mut self) {
        self.state_map = StateMap::default();
        self.copy_map.clear();
        self.non_normal_set = None;
        self.other_parent_set = None;
    }

    /// Add a tracked file to the dirstate
    pub fn add_file(
        &mut self,
        filename: &HgPath,
        old_state: EntryState,
        entry: DirstateEntry,
    ) -> Result<(), DirstateError> {
        if old_state == EntryState::Unknown || old_state == EntryState::Removed
        {
            if let Some(ref mut dirs) = self.dirs {
                dirs.add_path(filename)?;
            }
        }
        if old_state == EntryState::Unknown {
            if let Some(ref mut all_dirs) = self.all_dirs {
                all_dirs.add_path(filename)?;
            }
        }
        self.state_map.insert(filename.to_owned(), entry.to_owned());

        if entry.is_non_normal() {
            self.get_non_normal_other_parent_entries()
                .0
                .insert(filename.to_owned());
        }

        if entry.is_from_other_parent() {
            self.get_non_normal_other_parent_entries()
                .1
                .insert(filename.to_owned());
        }
        Ok(())
    }

    /// Mark a file as removed in the dirstate.
    ///
    /// The `size` parameter is used to store sentinel values that indicate
    /// the file's previous state.  In the future, we should refactor this
    /// to be more explicit about what that state is.
    pub fn remove_file(
        &mut self,
        filename: &HgPath,
        old_state: EntryState,
        size: i32,
    ) -> Result<(), DirstateError> {
        if old_state != EntryState::Unknown && old_state != EntryState::Removed
        {
            if let Some(ref mut dirs) = self.dirs {
                dirs.delete_path(filename)?;
            }
        }
        if old_state == EntryState::Unknown {
            if let Some(ref mut all_dirs) = self.all_dirs {
                all_dirs.add_path(filename)?;
            }
        }

        self.state_map.insert(
            filename.to_owned(),
            DirstateEntry {
                state: EntryState::Removed,
                mode: 0,
                size,
                mtime: 0,
            },
        );
        self.get_non_normal_other_parent_entries()
            .0
            .insert(filename.to_owned());
        Ok(())
    }

    /// Remove a file from the dirstate.
    /// Returns `true` if the file was previously recorded.
    pub fn drop_file(
        &mut self,
        filename: &HgPath,
        old_state: EntryState,
    ) -> Result<bool, DirstateError> {
        let exists = self.state_map.remove(filename).is_some();

        if exists {
            if old_state != EntryState::Removed {
                if let Some(ref mut dirs) = self.dirs {
                    dirs.delete_path(filename)?;
                }
            }
            if let Some(ref mut all_dirs) = self.all_dirs {
                all_dirs.delete_path(filename)?;
            }
        }
        self.get_non_normal_other_parent_entries()
            .0
            .remove(filename);

        Ok(exists)
    }

    pub fn clear_ambiguous_times(
        &mut self,
        filenames: Vec<HgPathBuf>,
        now: i32,
    ) {
        for filename in filenames {
            if let Some(entry) = self.state_map.get_mut(&filename) {
                if entry.clear_ambiguous_mtime(now) {
                    self.get_non_normal_other_parent_entries()
                        .0
                        .insert(filename.to_owned());
                }
            }
        }
    }

    pub fn non_normal_entries_remove(&mut self, key: impl AsRef<HgPath>) {
        self.get_non_normal_other_parent_entries()
            .0
            .remove(key.as_ref());
    }

    pub fn non_normal_entries_union(
        &mut self,
        other: HashSet<HgPathBuf>,
    ) -> Vec<HgPathBuf> {
        self.get_non_normal_other_parent_entries()
            .0
            .union(&other)
            .map(ToOwned::to_owned)
            .collect()
    }

    pub fn get_non_normal_other_parent_entries(
        &mut self,
    ) -> (&mut HashSet<HgPathBuf>, &mut HashSet<HgPathBuf>) {
        self.set_non_normal_other_parent_entries(false);
        (
            self.non_normal_set.as_mut().unwrap(),
            self.other_parent_set.as_mut().unwrap(),
        )
    }

    /// Useful to get immutable references to those sets in contexts where
    /// you only have an immutable reference to the `DirstateMap`, like when
    /// sharing references with Python.
    ///
    /// TODO, get rid of this along with the other "setter/getter" stuff when
    /// a nice typestate plan is defined.
    ///
    /// # Panics
    ///
    /// Will panic if either set is `None`.
    pub fn get_non_normal_other_parent_entries_panic(
        &self,
    ) -> (&HashSet<HgPathBuf>, &HashSet<HgPathBuf>) {
        (
            self.non_normal_set.as_ref().unwrap(),
            self.other_parent_set.as_ref().unwrap(),
        )
    }

    pub fn set_non_normal_other_parent_entries(&mut self, force: bool) {
        if !force
            && self.non_normal_set.is_some()
            && self.other_parent_set.is_some()
        {
            return;
        }
        let mut non_normal = HashSet::new();
        let mut other_parent = HashSet::new();

        for (filename, entry) in self.state_map.iter() {
            if entry.is_non_normal() {
                non_normal.insert(filename.to_owned());
            }
            if entry.is_from_other_parent() {
                other_parent.insert(filename.to_owned());
            }
        }
        self.non_normal_set = Some(non_normal);
        self.other_parent_set = Some(other_parent);
    }

    /// Both of these setters and their uses appear to be the simplest way to
    /// emulate a Python lazy property, but it is ugly and unidiomatic.
    /// TODO One day, rewriting this struct using the typestate might be a
    /// good idea.
    pub fn set_all_dirs(&mut self) -> Result<(), DirstateError> {
        if self.all_dirs.is_none() {
            self.all_dirs = Some(DirsMultiset::from_dirstate(
                self.state_map.iter().map(|(k, v)| Ok((k, *v))),
                None,
            )?);
        }
        Ok(())
    }

    pub fn set_dirs(&mut self) -> Result<(), DirstateError> {
        if self.dirs.is_none() {
            self.dirs = Some(DirsMultiset::from_dirstate(
                self.state_map.iter().map(|(k, v)| Ok((k, *v))),
                Some(EntryState::Removed),
            )?);
        }
        Ok(())
    }

    pub fn has_tracked_dir(
        &mut self,
        directory: &HgPath,
    ) -> Result<bool, DirstateError> {
        self.set_dirs()?;
        Ok(self.dirs.as_ref().unwrap().contains(directory))
    }

    pub fn has_dir(
        &mut self,
        directory: &HgPath,
    ) -> Result<bool, DirstateError> {
        self.set_all_dirs()?;
        Ok(self.all_dirs.as_ref().unwrap().contains(directory))
    }

    #[timed]
    pub fn read(
        &mut self,
        file_contents: &[u8],
    ) -> Result<Option<DirstateParents>, DirstateError> {
        if file_contents.is_empty() {
            return Ok(None);
        }

        let (parents, entries, copies) = parse_dirstate(file_contents)?;
        self.state_map.extend(
            entries
                .into_iter()
                .map(|(path, entry)| (path.to_owned(), entry)),
        );
        self.copy_map.extend(
            copies
                .into_iter()
                .map(|(path, copy)| (path.to_owned(), copy.to_owned())),
        );
        Ok(Some(parents.clone()))
    }

    pub fn pack(
        &mut self,
        parents: DirstateParents,
        now: Timestamp,
    ) -> Result<Vec<u8>, DirstateError> {
        let packed =
            pack_dirstate(&mut self.state_map, &self.copy_map, parents, now)?;

        self.set_non_normal_other_parent_entries(true);
        Ok(packed)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_dirs_multiset() {
        let mut map = DirstateMap::new();
        assert!(map.dirs.is_none());
        assert!(map.all_dirs.is_none());

        assert_eq!(map.has_dir(HgPath::new(b"nope")).unwrap(), false);
        assert!(map.all_dirs.is_some());
        assert!(map.dirs.is_none());

        assert_eq!(map.has_tracked_dir(HgPath::new(b"nope")).unwrap(), false);
        assert!(map.dirs.is_some());
    }

    #[test]
    fn test_add_file() {
        let mut map = DirstateMap::new();

        assert_eq!(0, map.len());

        map.add_file(
            HgPath::new(b"meh"),
            EntryState::Normal,
            DirstateEntry {
                state: EntryState::Normal,
                mode: 1337,
                mtime: 1337,
                size: 1337,
            },
        )
        .unwrap();

        assert_eq!(1, map.len());
        assert_eq!(0, map.get_non_normal_other_parent_entries().0.len());
        assert_eq!(0, map.get_non_normal_other_parent_entries().1.len());
    }

    #[test]
    fn test_non_normal_other_parent_entries() {
        let mut map: DirstateMap = [
            (b"f1", (EntryState::Removed, 1337, 1337, 1337)),
            (b"f2", (EntryState::Normal, 1337, 1337, -1)),
            (b"f3", (EntryState::Normal, 1337, 1337, 1337)),
            (b"f4", (EntryState::Normal, 1337, -2, 1337)),
            (b"f5", (EntryState::Added, 1337, 1337, 1337)),
            (b"f6", (EntryState::Added, 1337, 1337, -1)),
            (b"f7", (EntryState::Merged, 1337, 1337, -1)),
            (b"f8", (EntryState::Merged, 1337, 1337, 1337)),
            (b"f9", (EntryState::Merged, 1337, -2, 1337)),
            (b"fa", (EntryState::Added, 1337, -2, 1337)),
            (b"fb", (EntryState::Removed, 1337, -2, 1337)),
        ]
        .iter()
        .map(|(fname, (state, mode, size, mtime))| {
            (
                HgPathBuf::from_bytes(fname.as_ref()),
                DirstateEntry {
                    state: *state,
                    mode: *mode,
                    size: *size,
                    mtime: *mtime,
                },
            )
        })
        .collect();

        let mut non_normal = [
            b"f1", b"f2", b"f5", b"f6", b"f7", b"f8", b"f9", b"fa", b"fb",
        ]
        .iter()
        .map(|x| HgPathBuf::from_bytes(x.as_ref()))
        .collect();

        let mut other_parent = HashSet::new();
        other_parent.insert(HgPathBuf::from_bytes(b"f4"));
        let entries = map.get_non_normal_other_parent_entries();

        assert_eq!(
            (&mut non_normal, &mut other_parent),
            (entries.0, entries.1)
        );
    }
}