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use std::{cmp::Ordering, ops::Range};
use bstr::{BStr, ByteSlice, ByteVec};
use filetime::FileTime;
use crate::entry::{Stage, StageRaw};
use crate::{entry, extension, AccelerateLookup, Entry, PathStorage, PathStorageRef, State, Version};
// TODO: integrate this somehow, somewhere, depending on later usage.
#[allow(dead_code)]
mod sparse;
/// General information and entries
impl State {
/// Return the version used to store this state's information on disk.
pub fn version(&self) -> Version {
self.version
}
/// Returns time at which the state was created, indicating its freshness compared to other files on disk.
pub fn timestamp(&self) -> FileTime {
self.timestamp
}
/// Updates the timestamp of this state, indicating its freshness compared to other files on disk.
///
/// Be careful about using this as setting a timestamp without correctly updating the index
/// **will cause (file system) race conditions** see racy-git.txt in the git documentation
/// for more details.
pub fn set_timestamp(&mut self, timestamp: FileTime) {
self.timestamp = timestamp
}
/// Return the kind of hashes used in this instance.
pub fn object_hash(&self) -> gix_hash::Kind {
self.object_hash
}
/// Return our entries
pub fn entries(&self) -> &[Entry] {
&self.entries
}
/// Return our path backing, the place which keeps all paths one after another, with entries storing only the range to access them.
pub fn path_backing(&self) -> &PathStorageRef {
&self.path_backing
}
/// Runs `filter_map` on all entries, returning an iterator over all paths along with the result of `filter_map`.
pub fn entries_with_paths_by_filter_map<'a, T>(
&'a self,
mut filter_map: impl FnMut(&'a BStr, &Entry) -> Option<T> + 'a,
) -> impl Iterator<Item = (&'a BStr, T)> + 'a {
self.entries.iter().filter_map(move |e| {
let p = e.path(self);
filter_map(p, e).map(|t| (p, t))
})
}
/// Return mutable entries along with their path, as obtained from `backing`.
pub fn entries_mut_with_paths_in<'state, 'backing>(
&'state mut self,
backing: &'backing PathStorageRef,
) -> impl Iterator<Item = (&'state mut Entry, &'backing BStr)> {
self.entries.iter_mut().map(move |e| {
let path = backing[e.path.clone()].as_bstr();
(e, path)
})
}
/// Find the entry index in [`entries()`][State::entries()] matching the given repository-relative
/// `path` and `stage`, or `None`.
///
/// Use the index for accessing multiple stages if they exists, but at least the single matching entry.
pub fn entry_index_by_path_and_stage(&self, path: &BStr, stage: entry::Stage) -> Option<usize> {
let mut stage_cmp = Ordering::Equal;
let idx = self
.entries
.binary_search_by(|e| {
let res = e.path(self).cmp(path);
if res.is_eq() {
stage_cmp = e.stage().cmp(&stage);
}
res
})
.ok()?;
self.entry_index_by_idx_and_stage(path, idx, stage as StageRaw, stage_cmp)
}
/// Walk as far in `direction` as possible, with [`Ordering::Greater`] towards higher stages, and [`Ordering::Less`]
/// towards lower stages, and return the lowest or highest seen stage.
/// Return `None` if there is no greater or smaller stage.
fn walk_entry_stages(&self, path: &BStr, base: usize, direction: Ordering) -> Option<usize> {
match direction {
Ordering::Greater => self
.entries
.get(base + 1..)?
.iter()
.enumerate()
.take_while(|(_, e)| e.path(self) == path)
.last()
.map(|(idx, _)| base + 1 + idx),
Ordering::Equal => Some(base),
Ordering::Less => self.entries[..base]
.iter()
.enumerate()
.rev()
.take_while(|(_, e)| e.path(self) == path)
.last()
.map(|(idx, _)| idx),
}
}
fn entry_index_by_idx_and_stage(
&self,
path: &BStr,
idx: usize,
wanted_stage: entry::StageRaw,
stage_cmp: Ordering,
) -> Option<usize> {
match stage_cmp {
Ordering::Greater => self.entries[..idx]
.iter()
.enumerate()
.rev()
.take_while(|(_, e)| e.path(self) == path)
.find_map(|(idx, e)| (e.stage_raw() == wanted_stage).then_some(idx)),
Ordering::Equal => Some(idx),
Ordering::Less => self
.entries
.get(idx + 1..)?
.iter()
.enumerate()
.take_while(|(_, e)| e.path(self) == path)
.find_map(|(ofs, e)| (e.stage_raw() == wanted_stage).then_some(idx + ofs + 1)),
}
}
/// Return a data structure to help with case-insensitive lookups.
///
/// It's required perform any case-insensitive lookup.
/// TODO: needs multi-threaded insertion, raw-table to have multiple locks depending on bucket.
pub fn prepare_icase_backing(&self) -> AccelerateLookup<'_> {
let _span = gix_features::trace::detail!("prepare_icase_backing", entries = self.entries.len());
let mut out = AccelerateLookup::with_capacity(self.entries.len());
for entry in &self.entries {
let entry_path = entry.path(self);
let hash = AccelerateLookup::icase_hash(entry_path);
out.icase_entries
.insert_unique(hash, entry, |e| AccelerateLookup::icase_hash(e.path(self)));
let mut last_pos = entry_path.len();
while let Some(slash_idx) = entry_path[..last_pos].rfind_byte(b'/') {
let dir = entry_path[..slash_idx].as_bstr();
last_pos = slash_idx;
let dir_range = entry.path.start..(entry.path.start + dir.len());
let hash = AccelerateLookup::icase_hash(dir);
if out
.icase_dirs
.find(hash, |dir| {
dir.path(self) == self.path_backing[dir_range.clone()].as_bstr()
})
.is_none()
{
out.icase_dirs.insert_unique(
hash,
crate::DirEntry {
entry,
dir_end: dir_range.end,
},
|dir| AccelerateLookup::icase_hash(dir.path(self)),
);
} else {
break;
}
}
}
gix_features::trace::debug!(directories = out.icase_dirs.len(), "stored directories");
out
}
/// Return the entry at `path` that is at the lowest available stage, using `lookup` for acceleration.
/// It must have been created from this instance, and was ideally kept up-to-date with it.
///
/// If `ignore_case` is `true`, a case-insensitive (ASCII-folding only) search will be performed.
pub fn entry_by_path_icase<'a>(
&'a self,
path: &BStr,
ignore_case: bool,
lookup: &AccelerateLookup<'a>,
) -> Option<&'a Entry> {
lookup
.icase_entries
.find(AccelerateLookup::icase_hash(path), |e| {
let entry_path = e.path(self);
if entry_path == path {
return true;
};
if !ignore_case {
return false;
}
entry_path.eq_ignore_ascii_case(path)
})
.copied()
}
/// Return the entry (at any stage) that is inside of `directory`, or `None`,
/// using `lookup` for acceleration.
/// Note that submodules are not detected as directories and the user should
/// make another call to [`entry_by_path_icase()`](Self::entry_by_path_icase) to check for this
/// possibility. Doing so might also reveal a sparse directory.
///
/// If `ignore_case` is set
pub fn entry_closest_to_directory_icase<'a>(
&'a self,
directory: &BStr,
ignore_case: bool,
lookup: &AccelerateLookup<'a>,
) -> Option<&Entry> {
lookup
.icase_dirs
.find(AccelerateLookup::icase_hash(directory), |dir| {
let dir_path = dir.path(self);
if dir_path == directory {
return true;
};
if !ignore_case {
return false;
}
dir_path.eq_ignore_ascii_case(directory)
})
.map(|dir| dir.entry)
}
/// Return the entry (at any stage) that is inside of `directory`, or `None`.
/// Note that submodules are not detected as directories and the user should
/// make another call to [`entry_by_path_icase()`](Self::entry_by_path_icase) to check for this
/// possibility. Doing so might also reveal a sparse directory.
///
/// Note that this is a case-sensitive search.
pub fn entry_closest_to_directory(&self, directory: &BStr) -> Option<&Entry> {
let idx = self.entry_index_by_path(directory).err()?;
for entry in &self.entries[idx..] {
let path = entry.path(self);
if path.get(..directory.len())? != directory {
break;
}
let dir_char = path.get(directory.len())?;
if *dir_char > b'/' {
break;
}
if *dir_char < b'/' {
continue;
}
return Some(entry);
}
None
}
/// Find the entry index in [`entries()[..upper_bound]`][State::entries()] matching the given repository-relative
/// `path` and `stage`, or `None`.
///
/// Use the index for accessing multiple stages if they exists, but at least the single matching entry.
///
/// # Panics
///
/// If `upper_bound` is out of bounds of our entries array.
pub fn entry_index_by_path_and_stage_bounded(
&self,
path: &BStr,
stage: entry::Stage,
upper_bound: usize,
) -> Option<usize> {
self.entries[..upper_bound]
.binary_search_by(|e| e.path(self).cmp(path).then_with(|| e.stage().cmp(&stage)))
.ok()
}
/// Like [`entry_index_by_path_and_stage()`](State::entry_index_by_path_and_stage()),
/// but returns the entry instead of the index.
pub fn entry_by_path_and_stage(&self, path: &BStr, stage: entry::Stage) -> Option<&Entry> {
self.entry_index_by_path_and_stage(path, stage)
.map(|idx| &self.entries[idx])
}
/// Return the entry at `path` that is either at stage 0, or at stage 2 (ours) in case of a merge conflict.
///
/// Using this method is more efficient in comparison to doing two searches, one for stage 0 and one for stage 2.
pub fn entry_by_path(&self, path: &BStr) -> Option<&Entry> {
let mut stage_at_index = 0;
let idx = self
.entries
.binary_search_by(|e| {
let res = e.path(self).cmp(path);
if res.is_eq() {
stage_at_index = e.stage_raw();
}
res
})
.ok()?;
let idx = if stage_at_index == 0 || stage_at_index == 2 {
idx
} else {
self.entry_index_by_idx_and_stage(path, idx, Stage::Ours as StageRaw, stage_at_index.cmp(&2))?
};
Some(&self.entries[idx])
}
/// Return the index at `Ok(index)` where the entry matching `path` (in any stage) can be found, or return
/// `Err(index)` to indicate the insertion position at which an entry with `path` would fit in.
pub fn entry_index_by_path(&self, path: &BStr) -> Result<usize, usize> {
self.entries.binary_search_by(|e| e.path(self).cmp(path))
}
/// Return the slice of entries which all share the same `prefix`, or `None` if there isn't a single such entry.
///
/// If `prefix` is empty, all entries are returned.
pub fn prefixed_entries(&self, prefix: &BStr) -> Option<&[Entry]> {
self.prefixed_entries_range(prefix).map(|range| &self.entries[range])
}
/// Return the range of entries which all share the same `prefix`, or `None` if there isn't a single such entry.
///
/// If `prefix` is empty, the range will include all entries.
pub fn prefixed_entries_range(&self, prefix: &BStr) -> Option<Range<usize>> {
if prefix.is_empty() {
return Some(0..self.entries.len());
}
let prefix_len = prefix.len();
let mut low = self.entries.partition_point(|e| {
e.path(self)
.get(..prefix_len)
.map_or_else(|| e.path(self) <= &prefix[..e.path.len()], |p| p < prefix)
});
let mut high = low
+ self.entries[low..].partition_point(|e| e.path(self).get(..prefix_len).map_or(false, |p| p <= prefix));
let low_entry = &self.entries.get(low)?;
if low_entry.stage_raw() != 0 {
low = self
.walk_entry_stages(low_entry.path(self), low, Ordering::Less)
.unwrap_or(low);
}
if let Some(high_entry) = self.entries.get(high) {
if high_entry.stage_raw() != 0 {
high = self
.walk_entry_stages(high_entry.path(self), high, Ordering::Less)
.unwrap_or(high);
}
}
(low != high).then_some(low..high)
}
/// Return the entry at `idx` or _panic_ if the index is out of bounds.
///
/// The `idx` is typically returned by [`entry_by_path_and_stage()`][State::entry_by_path_and_stage()].
pub fn entry(&self, idx: usize) -> &Entry {
&self.entries[idx]
}
/// Returns a boolean value indicating whether the index is sparse or not.
///
/// An index is sparse if it contains at least one [`Mode::DIR`][entry::Mode::DIR] entry.
pub fn is_sparse(&self) -> bool {
self.is_sparse
}
/// Return the range of entries that exactly match the given `path`, in all available stages, or `None` if no entry with such
/// path exists.
///
/// The range can be used to access the respective entries via [`entries()`](Self::entries()) or [`entries_mut()](Self::entries_mut()).
pub fn entry_range(&self, path: &BStr) -> Option<Range<usize>> {
let mut stage_at_index = 0;
let idx = self
.entries
.binary_search_by(|e| {
let res = e.path(self).cmp(path);
if res.is_eq() {
stage_at_index = e.stage_raw();
}
res
})
.ok()?;
let (start, end) = (
self.walk_entry_stages(path, idx, Ordering::Less).unwrap_or(idx),
self.walk_entry_stages(path, idx, Ordering::Greater).unwrap_or(idx) + 1,
);
Some(start..end)
}
}
impl<'a> AccelerateLookup<'a> {
fn with_capacity(cap: usize) -> Self {
let ratio_of_entries_to_dirs_in_webkit = 20; // 400k entries and 20k dirs
Self {
icase_entries: hashbrown::HashTable::with_capacity(cap),
icase_dirs: hashbrown::HashTable::with_capacity(cap / ratio_of_entries_to_dirs_in_webkit),
}
}
fn icase_hash(data: &BStr) -> u64 {
use std::hash::Hasher;
let mut hasher = fnv::FnvHasher::default();
for b in data.as_bytes() {
hasher.write_u8(b.to_ascii_lowercase());
}
hasher.finish()
}
}
/// Mutation
impl State {
/// After usage of the storage obtained by [`take_path_backing()`][Self::take_path_backing()], return it here.
/// Note that it must not be empty.
pub fn return_path_backing(&mut self, backing: PathStorage) {
debug_assert!(
self.path_backing.is_empty(),
"BUG: return path backing only after taking it, once"
);
self.path_backing = backing;
}
/// Return mutable entries in a slice.
pub fn entries_mut(&mut self) -> &mut [Entry] {
&mut self.entries
}
/// Return a writable slice to entries and read-access to their path storage at the same time.
pub fn entries_mut_and_pathbacking(&mut self) -> (&mut [Entry], &PathStorageRef) {
(&mut self.entries, &self.path_backing)
}
/// Return mutable entries along with their paths in an iterator.
pub fn entries_mut_with_paths(&mut self) -> impl Iterator<Item = (&mut Entry, &BStr)> {
let paths = &self.path_backing;
self.entries.iter_mut().map(move |e| {
let path = paths[e.path.clone()].as_bstr();
(e, path)
})
}
/// Return all parts that relate to entries, which includes path storage.
///
/// This can be useful for obtaining a standalone, boxable iterator
pub fn into_entries(self) -> (Vec<Entry>, PathStorage) {
(self.entries, self.path_backing)
}
/// Sometimes it's needed to remove the path backing to allow certain mutation to happen in the state while supporting reading the entry's
/// path.
pub fn take_path_backing(&mut self) -> PathStorage {
assert_eq!(
self.entries.is_empty(),
self.path_backing.is_empty(),
"BUG: cannot take out backing multiple times"
);
std::mem::take(&mut self.path_backing)
}
/// Like [`entry_index_by_path_and_stage()`][State::entry_index_by_path_and_stage()],
/// but returns the mutable entry instead of the index.
pub fn entry_mut_by_path_and_stage(&mut self, path: &BStr, stage: entry::Stage) -> Option<&mut Entry> {
self.entry_index_by_path_and_stage(path, stage)
.map(|idx| &mut self.entries[idx])
}
/// Push a new entry containing `stat`, `id`, `flags` and `mode` and `path` to the end of our storage, without performing
/// any sanity checks. This means it's possible to push a new entry to the same path on the same stage and even after sorting
/// the entries lookups may still return the wrong one of them unless the correct binary search criteria is chosen.
///
/// Note that this *is likely* to break invariants that will prevent further lookups by path unless
/// [`entry_index_by_path_and_stage_bounded()`][State::entry_index_by_path_and_stage_bounded()] is used with
/// the `upper_bound` being the amount of entries before the first call to this method.
///
/// Alternatively, make sure to call [`sort_entries()`][State::sort_entries()] before entry lookup by path to restore
/// the invariant.
pub fn dangerously_push_entry(
&mut self,
stat: entry::Stat,
id: gix_hash::ObjectId,
flags: entry::Flags,
mode: entry::Mode,
path: &BStr,
) {
let path = {
let path_start = self.path_backing.len();
self.path_backing.push_str(path);
path_start..self.path_backing.len()
};
self.entries.push(Entry {
stat,
id,
flags,
mode,
path,
});
}
/// Unconditionally sort entries as needed to perform lookups quickly.
pub fn sort_entries(&mut self) {
let path_backing = &self.path_backing;
self.entries.sort_by(|a, b| {
Entry::cmp_filepaths(a.path_in(path_backing), b.path_in(path_backing))
.then_with(|| a.stage().cmp(&b.stage()))
});
}
/// Similar to [`sort_entries()`][State::sort_entries()], but applies `compare` after comparing
/// by path and stage as a third criteria.
pub fn sort_entries_by(&mut self, mut compare: impl FnMut(&Entry, &Entry) -> Ordering) {
let path_backing = &self.path_backing;
self.entries.sort_by(|a, b| {
Entry::cmp_filepaths(a.path_in(path_backing), b.path_in(path_backing))
.then_with(|| a.stage().cmp(&b.stage()))
.then_with(|| compare(a, b))
});
}
/// Physically remove all entries for which `should_remove(idx, path, entry)` returns `true`, traversing them from first to last.
///
/// Note that the memory used for the removed entries paths is not freed, as it's append-only.
///
/// ### Performance
///
/// To implement this operation typically, one would rather add [entry::Flags::REMOVE] to each entry to remove
/// them when [writing the index](Self::write_to()).
pub fn remove_entries(&mut self, mut should_remove: impl FnMut(usize, &BStr, &mut Entry) -> bool) {
let mut index = 0;
let paths = &self.path_backing;
self.entries.retain_mut(|e| {
let path = e.path_in(paths);
let res = !should_remove(index, path, e);
index += 1;
res
});
}
}
/// Extensions
impl State {
/// Access the `tree` extension.
pub fn tree(&self) -> Option<&extension::Tree> {
self.tree.as_ref()
}
/// Access the `link` extension.
pub fn link(&self) -> Option<&extension::Link> {
self.link.as_ref()
}
/// Obtain the resolve-undo extension.
pub fn resolve_undo(&self) -> Option<&extension::resolve_undo::Paths> {
self.resolve_undo.as_ref()
}
/// Obtain the untracked extension.
pub fn untracked(&self) -> Option<&extension::UntrackedCache> {
self.untracked.as_ref()
}
/// Obtain the fsmonitor extension.
pub fn fs_monitor(&self) -> Option<&extension::FsMonitor> {
self.fs_monitor.as_ref()
}
/// Return `true` if the end-of-index extension was present when decoding this index.
pub fn had_end_of_index_marker(&self) -> bool {
self.end_of_index_at_decode_time
}
/// Return `true` if the offset-table extension was present when decoding this index.
pub fn had_offset_table(&self) -> bool {
self.offset_table_at_decode_time
}
}
#[cfg(test)]
mod tests {
use std::path::{Path, PathBuf};
#[test]
fn entry_by_path_with_conflicting_file() {
let file = PathBuf::from("tests")
.join("fixtures")
.join(Path::new("loose_index").join("conflicting-file.git-index"));
let file = crate::File::at(file, gix_hash::Kind::Sha1, false, Default::default()).expect("valid file");
assert_eq!(
file.entries().len(),
3,
"we have a set of conflict entries for a single file"
);
for idx in 0..3 {
for wanted_stage in 1..=3 {
let actual_idx = file
.entry_index_by_idx_and_stage(
"file".into(),
idx,
wanted_stage,
(idx + 1).cmp(&(wanted_stage as usize)),
)
.expect("found");
assert_eq!(
actual_idx + 1,
wanted_stage as usize,
"the index and stage have a relation, and that is upheld if we search correctly"
);
}
}
}
}