comparison rust/hg-core/src/repo.rs @ 48419:c8659e61073d

rhg: Make Repo::dirstate_parents a LazyCell

Unify with the same abstraction used for other lazily-initialized components

Differential Revision: https://phab.mercurial-scm.org/D11837

48418:abeae090ce67

use crate::utils::hg_path::HgPath;
use crate::utils::SliceExt;
use crate::vfs::{is_dir, is_file, Vfs};
use crate::{requirements, NodePrefix};
use crate::{DirstateError, Revision};
use std::cell::{Cell, Ref, RefCell, RefMut};
use std::collections::HashSet;
use std::path::{Path, PathBuf};

/// A repository on disk
pub struct Repo {
    working_directory: PathBuf,
    dot_hg: PathBuf,
    store: PathBuf,
    requirements: HashSet<String>,
    config: Config,
    // None means not known/initialized yet
    dirstate_parents: Cell<Option<DirstateParents>>,
    dirstate_map: LazyCell<OwningDirstateMap, DirstateError>,
    changelog: LazyCell<Changelog, HgError>,
    manifestlog: LazyCell<Manifestlog, HgError>,
}

            requirements: reqs,
            working_directory,
            store: store_path,
            dot_hg,
            config: repo_config,
            dirstate_parents: Cell::new(None),
            dirstate_map: LazyCell::new(Self::new_dirstate_map),
            changelog: LazyCell::new(Changelog::open),
            manifestlog: LazyCell::new(Manifestlog::open),
        };

            .io_not_found_as_none()?
            .unwrap_or(Vec::new()))
    }

    pub fn dirstate_parents(&self) -> Result<DirstateParents, HgError> {
        if let Some(parents) = self.dirstate_parents.get() {
            return Ok(parents);
        }
        let dirstate = self.dirstate_file_contents()?;
        let parents = if dirstate.is_empty() {
            DirstateParents::NULL
        } else if self.has_dirstate_v2() {
            crate::dirstate_tree::on_disk::read_docket(&dirstate)?.parents()
        } else {
            crate::dirstate::parsers::parse_dirstate_parents(&dirstate)?
                .clone()
        };
        self.dirstate_parents.set(Some(parents));
        Ok(parents)
    }

    fn new_dirstate_map(&self) -> Result<OwningDirstateMap, DirstateError> {
        let dirstate_file_contents = self.dirstate_file_contents()?;
        if dirstate_file_contents.is_empty() {
            self.dirstate_parents.set(Some(DirstateParents::NULL));
            Ok(OwningDirstateMap::new_empty(Vec::new()))
        } else if self.has_dirstate_v2() {
            let docket = crate::dirstate_tree::on_disk::read_docket(
                &dirstate_file_contents,
            )?;
            self.dirstate_parents.set(Some(docket.parents()));
            let data_size = docket.data_size();
            let metadata = docket.tree_metadata();
            let mut map = if let Some(data_mmap) = self
                .hg_vfs()
                .mmap_open(docket.data_filename())

        } else {
            let mut map = OwningDirstateMap::new_empty(dirstate_file_contents);
            let (on_disk, placeholder) = map.get_pair_mut();
            let (inner, parents) = DirstateMap::new_v1(on_disk)?;
            self.dirstate_parents
                .set(Some(parents.unwrap_or(DirstateParents::NULL)));
            *placeholder = inner;
            Ok(map)
        }
    }

            value: RefCell::new(None),
            init: Box::new(init),
        }
    }

    fn get_or_init(&self, repo: &Repo) -> Result<Ref<T>, E> {
        let mut borrowed = self.value.borrow();
        if borrowed.is_none() {
            drop(borrowed);
            // Only use `borrow_mut` if it is really needed to avoid panic in

            borrowed = self.value.borrow()
        }
        Ok(Ref::map(borrowed, |option| option.as_ref().unwrap()))
    }

    pub fn get_mut_or_init(&self, repo: &Repo) -> Result<RefMut<T>, E> {
        let mut borrowed = self.value.borrow_mut();
        if borrowed.is_none() {
            *borrowed = Some((self.init)(repo)?);
        }
        Ok(RefMut::map(borrowed, |option| option.as_mut().unwrap()))

48419:c8659e61073d

use crate::utils::hg_path::HgPath;
use crate::utils::SliceExt;
use crate::vfs::{is_dir, is_file, Vfs};
use crate::{requirements, NodePrefix};
use crate::{DirstateError, Revision};
use std::cell::{Ref, RefCell, RefMut};
use std::collections::HashSet;
use std::path::{Path, PathBuf};

/// A repository on disk
pub struct Repo {
    working_directory: PathBuf,
    dot_hg: PathBuf,
    store: PathBuf,
    requirements: HashSet<String>,
    config: Config,
    dirstate_parents: LazyCell<DirstateParents, HgError>,
    dirstate_map: LazyCell<OwningDirstateMap, DirstateError>,
    changelog: LazyCell<Changelog, HgError>,
    manifestlog: LazyCell<Manifestlog, HgError>,
}

            requirements: reqs,
            working_directory,
            store: store_path,
            dot_hg,
            config: repo_config,
            dirstate_parents: LazyCell::new(Self::read_dirstate_parents),
            dirstate_map: LazyCell::new(Self::new_dirstate_map),
            changelog: LazyCell::new(Changelog::open),
            manifestlog: LazyCell::new(Manifestlog::open),
        };

            .io_not_found_as_none()?
            .unwrap_or(Vec::new()))
    }

    pub fn dirstate_parents(&self) -> Result<DirstateParents, HgError> {
        Ok(*self.dirstate_parents.get_or_init(self)?)
    }

    fn read_dirstate_parents(&self) -> Result<DirstateParents, HgError> {
        let dirstate = self.dirstate_file_contents()?;
        let parents = if dirstate.is_empty() {
            DirstateParents::NULL
        } else if self.has_dirstate_v2() {
            crate::dirstate_tree::on_disk::read_docket(&dirstate)?.parents()
        } else {
            crate::dirstate::parsers::parse_dirstate_parents(&dirstate)?
                .clone()
        };
        self.dirstate_parents.set(parents);
        Ok(parents)
    }

    fn new_dirstate_map(&self) -> Result<OwningDirstateMap, DirstateError> {
        let dirstate_file_contents = self.dirstate_file_contents()?;
        if dirstate_file_contents.is_empty() {
            self.dirstate_parents.set(DirstateParents::NULL);
            Ok(OwningDirstateMap::new_empty(Vec::new()))
        } else if self.has_dirstate_v2() {
            let docket = crate::dirstate_tree::on_disk::read_docket(
                &dirstate_file_contents,
            )?;
            self.dirstate_parents.set(docket.parents());
            let data_size = docket.data_size();
            let metadata = docket.tree_metadata();
            let mut map = if let Some(data_mmap) = self
                .hg_vfs()
                .mmap_open(docket.data_filename())

        } else {
            let mut map = OwningDirstateMap::new_empty(dirstate_file_contents);
            let (on_disk, placeholder) = map.get_pair_mut();
            let (inner, parents) = DirstateMap::new_v1(on_disk)?;
            self.dirstate_parents
                .set(parents.unwrap_or(DirstateParents::NULL));
            *placeholder = inner;
            Ok(map)
        }
    }

            value: RefCell::new(None),
            init: Box::new(init),
        }
    }

    fn set(&self, value: T) {
        *self.value.borrow_mut() = Some(value)
    }

    fn get_or_init(&self, repo: &Repo) -> Result<Ref<T>, E> {
        let mut borrowed = self.value.borrow();
        if borrowed.is_none() {
            drop(borrowed);
            // Only use `borrow_mut` if it is really needed to avoid panic in

            borrowed = self.value.borrow()
        }
        Ok(Ref::map(borrowed, |option| option.as_ref().unwrap()))
    }

    fn get_mut_or_init(&self, repo: &Repo) -> Result<RefMut<T>, E> {
        let mut borrowed = self.value.borrow_mut();
        if borrowed.is_none() {
            *borrowed = Some((self.init)(repo)?);
        }
        Ok(RefMut::map(borrowed, |option| option.as_mut().unwrap()))