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rust-nodemap: pure Rust example...
rust-nodemap: pure Rust example To run, use `cargo run --release --example nodemap` This demonstrates that simple scenarios entirely written in Rust can content themselves with `NodeTree<T>`. The example mmaps both the nodemap file and the changelog index. We had of course to include an implementation of `RevlogIndex` directly, which isn't much at this stage. It felt a bit prematurate to include it in the lib. Here are some first performance measurements, obtained with this example, on a clone of mozilla-central with 440000 changesets: (create) Nodemap constructed in RAM in 153.638305ms (query CAE63161B68962) found in 22.362us: Ok(Some(269489)) (bench) Did 3 queries in 36.418µs (mean 12.139µs) (bench) Did 50 queries in 184.318µs (mean 3.686µs) (bench) Did 100000 queries in 31.053461ms (mean 310ns) To be fair, even between bench runs, results tend to depend whether the file is still in kernel caches, and it's not so easy to get back to a real cold start. The worst we've seen was in the 50us ballpark. In any busy server setting, the pages would always be in RAM. We hope it's good enough not to be significantly slower on any concrete Mercurial operation than the C nodetree when fully in RAM, and of course this implementation has the serious headstart advantage of persistence. Differential Revision: https://phab.mercurial-scm.org/D7797

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dirstate_map.rs
478 lines | 13.9 KiB | application/rls-services+xml | RustLexer
// dirstate_map.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.
use crate::{
dirstate::{parsers::PARENT_SIZE, EntryState, SIZE_FROM_OTHER_PARENT},
pack_dirstate, parse_dirstate,
utils::{
files::normalize_case,
hg_path::{HgPath, HgPathBuf},
},
CopyMap, DirsMultiset, DirstateEntry, DirstateError, DirstateMapError,
DirstateParents, DirstateParseError, FastHashMap, StateMap,
};
use core::borrow::Borrow;
use std::collections::HashSet;
use std::convert::TryInto;
use std::iter::FromIterator;
use std::ops::Deref;
use std::time::Duration;
pub type FileFoldMap = FastHashMap<HgPathBuf, HgPathBuf>;
const NULL_ID: [u8; 20] = [0; 20];
const MTIME_UNSET: i32 = -1;
#[derive(Default)]
pub struct DirstateMap {
state_map: StateMap,
pub copy_map: CopyMap,
file_fold_map: Option<FileFoldMap>,
pub dirs: Option<DirsMultiset>,
pub all_dirs: Option<DirsMultiset>,
non_normal_set: Option<HashSet<HgPathBuf>>,
other_parent_set: Option<HashSet<HgPathBuf>>,
parents: Option<DirstateParents>,
dirty_parents: bool,
}
/// 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.clear();
self.copy_map.clear();
self.file_fold_map = None;
self.non_normal_set = None;
self.other_parent_set = None;
self.set_parents(&DirstateParents {
p1: NULL_ID,
p2: NULL_ID,
})
}
/// Add a tracked file to the dirstate
pub fn add_file(
&mut self,
filename: &HgPath,
old_state: EntryState,
entry: DirstateEntry,
) -> Result<(), DirstateMapError> {
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.state != EntryState::Normal || entry.mtime == MTIME_UNSET {
self.get_non_normal_other_parent_entries()
.0
.insert(filename.to_owned());
}
if entry.size == SIZE_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<(), DirstateMapError> {
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)?;
}
}
if let Some(ref mut file_fold_map) = self.file_fold_map {
file_fold_map.remove(&normalize_case(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, DirstateMapError> {
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)?;
}
}
if let Some(ref mut file_fold_map) = self.file_fold_map {
file_fold_map.remove(&normalize_case(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 {
let mut changed = false;
self.state_map
.entry(filename.to_owned())
.and_modify(|entry| {
if entry.state == EntryState::Normal && entry.mtime == now
{
changed = true;
*entry = DirstateEntry {
mtime: MTIME_UNSET,
..*entry
};
}
});
if changed {
self.get_non_normal_other_parent_entries()
.0
.insert(filename.to_owned());
}
}
}
pub fn non_normal_entries_remove(
&mut self,
key: impl AsRef<HgPath>,
) -> bool {
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(|e| e.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(),
)
}
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,
DirstateEntry {
state, size, mtime, ..
},
) in self.state_map.iter()
{
if *state != EntryState::Normal || *mtime == MTIME_UNSET {
non_normal.insert(filename.to_owned());
}
if *state == EntryState::Normal && *size == SIZE_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<(), DirstateMapError> {
if self.all_dirs.is_none() {
self.all_dirs =
Some(DirsMultiset::from_dirstate(&self.state_map, None)?);
}
Ok(())
}
pub fn set_dirs(&mut self) -> Result<(), DirstateMapError> {
if self.dirs.is_none() {
self.dirs = Some(DirsMultiset::from_dirstate(
&self.state_map,
Some(EntryState::Removed),
)?);
}
Ok(())
}
pub fn has_tracked_dir(
&mut self,
directory: &HgPath,
) -> Result<bool, DirstateMapError> {
self.set_dirs()?;
Ok(self.dirs.as_ref().unwrap().contains(directory))
}
pub fn has_dir(
&mut self,
directory: &HgPath,
) -> Result<bool, DirstateMapError> {
self.set_all_dirs()?;
Ok(self.all_dirs.as_ref().unwrap().contains(directory))
}
pub fn parents(
&mut self,
file_contents: &[u8],
) -> Result<&DirstateParents, DirstateError> {
if let Some(ref parents) = self.parents {
return Ok(parents);
}
let parents;
if file_contents.len() == PARENT_SIZE * 2 {
parents = DirstateParents {
p1: file_contents[..PARENT_SIZE].try_into().unwrap(),
p2: file_contents[PARENT_SIZE..PARENT_SIZE * 2]
.try_into()
.unwrap(),
};
} else if file_contents.is_empty() {
parents = DirstateParents {
p1: NULL_ID,
p2: NULL_ID,
};
} else {
return Err(DirstateError::Parse(DirstateParseError::Damaged));
}
self.parents = Some(parents);
Ok(self.parents.as_ref().unwrap())
}
pub fn set_parents(&mut self, parents: &DirstateParents) {
self.parents = Some(parents.clone());
self.dirty_parents = true;
}
pub fn read(
&mut self,
file_contents: &[u8],
) -> Result<Option<DirstateParents>, DirstateError> {
if file_contents.is_empty() {
return Ok(None);
}
let parents = parse_dirstate(
&mut self.state_map,
&mut self.copy_map,
file_contents,
)?;
if !self.dirty_parents {
self.set_parents(&parents);
}
Ok(Some(parents))
}
pub fn pack(
&mut self,
parents: DirstateParents,
now: Duration,
) -> Result<Vec<u8>, DirstateError> {
let packed =
pack_dirstate(&mut self.state_map, &self.copy_map, parents, now)?;
self.dirty_parents = false;
self.set_non_normal_other_parent_entries(true);
Ok(packed)
}
pub fn build_file_fold_map(&mut self) -> &FileFoldMap {
if let Some(ref file_fold_map) = self.file_fold_map {
return file_fold_map;
}
let mut new_file_fold_map = FileFoldMap::default();
for (filename, DirstateEntry { state, .. }) in self.state_map.borrow()
{
if *state == EntryState::Removed {
new_file_fold_map
.insert(normalize_case(filename), filename.to_owned());
}
}
self.file_fold_map = Some(new_file_fold_map);
self.file_fold_map.as_ref().unwrap()
}
}
#[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)
);
}
}