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Differential D10722

dirstate-v2: Change the on-disk format to be tree-shaped
ClosedPublic

Authored by SimonSapin on May 17 2021, 6:06 AM.

Details

Reviewers
Alphare
Group Reviewers
hg-reviewers
Commits
rHG2a9ddc8094c7: dirstate-v2: Change the on-disk format to be tree-shaped
rHG604aa7eca30d: dirstate-v2: Change the on-disk format to be tree-shaped
Summary

Nodes are stored not only for tracked files but also for their ancestor
directories. A node has "pointers" (byte count from the start of the file)
to its direct child nodes. Everything can be accessed with zero copy.

Diff Detail

Repository
rHG Mercurial
Branch
default
Lint
No Linters Available
Unit
No Unit Test Coverage

Event Timeline

SimonSapin created this revision.May 17 2021, 6:06 AM
baymax updated this revision to Diff 28002.May 17 2021, 8:39 AM

✅ refresh by Heptapod after a successful CI run (🐙 💚)

Alphare accepted this revision.May 19 2021, 6:19 AM
Alphare added a subscriber: Alphare.
Alphare added inline comments.
rust/hg-core/src/dirstate_tree/dirstate_map.rs
36

4 billion files is not webscale ;)

rust/hg-core/src/dirstate_tree/on_disk.rs
241

This will be done differently when we move to an append-only format anyway, no need to worry about it.

This revision is now accepted and ready to land.May 19 2021, 6:19 AM
baymax updated this revision to Diff 28103.May 19 2021, 7:41 AM

✅ refresh by Heptapod after a successful CI run (🐙 💚)

Revision Contents
Changeset List

Diff 28103

rust/hg-core/src/dirstate_tree/dirstate_map.rs

use bytes_cast::BytesCast; use bytes_cast::BytesCast;
use micro_timer::timed; use micro_timer::timed;
use std::borrow::Cow; use std::borrow::Cow;
use std::convert::TryInto; use std::convert::TryInto;
use std::path::PathBuf; use std::path::PathBuf;
use super::on_disk::V2_FORMAT_MARKER; use super::on_disk;
use super::path_with_basename::WithBasename; use super::path_with_basename::WithBasename;
use crate::dirstate::parsers::clear_ambiguous_mtime; use crate::dirstate::parsers::clear_ambiguous_mtime;
use crate::dirstate::parsers::pack_entry; use crate::dirstate::parsers::pack_entry;
use crate::dirstate::parsers::packed_entry_size; use crate::dirstate::parsers::packed_entry_size;
use crate::dirstate::parsers::parse_dirstate_entries; use crate::dirstate::parsers::parse_dirstate_entries;
use crate::dirstate::parsers::Timestamp; use crate::dirstate::parsers::Timestamp;
use crate::errors::HgError;
use crate::matchers::Matcher; use crate::matchers::Matcher;
use crate::utils::hg_path::{HgPath, HgPathBuf}; use crate::utils::hg_path::{HgPath, HgPathBuf};
use crate::utils::SliceExt;
use crate::CopyMapIter; use crate::CopyMapIter;
use crate::DirstateEntry; use crate::DirstateEntry;
use crate::DirstateError; use crate::DirstateError;
use crate::DirstateMapError; use crate::DirstateMapError;
use crate::DirstateParents; use crate::DirstateParents;
use crate::DirstateStatus; use crate::DirstateStatus;
use crate::EntryState; use crate::EntryState;
use crate::FastHashMap; use crate::FastHashMap;
use crate::PatternFileWarning; use crate::PatternFileWarning;
use crate::StateMapIter; use crate::StateMapIter;
use crate::StatusError; use crate::StatusError;
use crate::StatusOptions; use crate::StatusOptions;
pub struct DirstateMap<'on_disk> { pub struct DirstateMap<'on_disk> {
/// Contents of the `.hg/dirstate` file /// Contents of the `.hg/dirstate` file
on_disk: &'on_disk [u8], pub(super) on_disk: &'on_disk [u8],
pub(super) root: ChildNodes<'on_disk>, pub(super) root: ChildNodes<'on_disk>,
/// Number of nodes anywhere in the tree that have `.entry.is_some()`. /// Number of nodes anywhere in the tree that have `.entry.is_some()`.
nodes_with_entry_count: usize, pub(super) nodes_with_entry_count: u32,
AlphareUnsubmitted
Not Done

4 billion files is not webscale ;)

Alphare: 4 billion files is not webscale ;)
/// Number of nodes anywhere in the tree that have /// Number of nodes anywhere in the tree that have
/// `.copy_source.is_some()`. /// `.copy_source.is_some()`.
nodes_with_copy_source_count: usize, pub(super) nodes_with_copy_source_count: u32,
} }
/// Using a plain `HgPathBuf` of the full path from the repository root as a /// Using a plain `HgPathBuf` of the full path from the repository root as a
/// map key would also work: all paths in a given map have the same parent /// map key would also work: all paths in a given map have the same parent
/// path, so comparing full paths gives the same result as comparing base /// path, so comparing full paths gives the same result as comparing base
/// names. However `HashMap` would waste time always re-hashing the same /// names. However `HashMap` would waste time always re-hashing the same
/// string prefix. /// string prefix.
pub(super) type NodeKey<'on_disk> = WithBasename<Cow<'on_disk, HgPath>>; pub(super) type NodeKey<'on_disk> = WithBasename<Cow<'on_disk, HgPath>>;
pub(super) type ChildNodes<'on_disk> = pub(super) type ChildNodes<'on_disk> =
FastHashMap<NodeKey<'on_disk>, Node<'on_disk>>; FastHashMap<NodeKey<'on_disk>, Node<'on_disk>>;
/// Represents a file or a directory /// Represents a file or a directory
#[derive(Default)] #[derive(Default)]
pub(super) struct Node<'on_disk> { pub(super) struct Node<'on_disk> {
/// `None` for directories /// `None` for directories
pub(super) entry: Option<DirstateEntry>, pub(super) entry: Option<DirstateEntry>,
pub(super) copy_source: Option<Cow<'on_disk, HgPath>>, pub(super) copy_source: Option<Cow<'on_disk, HgPath>>,
pub(super) children: ChildNodes<'on_disk>, pub(super) children: ChildNodes<'on_disk>,
/// How many (non-inclusive) descendants of this node are tracked files /// How many (non-inclusive) descendants of this node are tracked files
tracked_descendants_count: usize, pub(super) tracked_descendants_count: u32,
} }
impl<'on_disk> Node<'on_disk> { impl<'on_disk> Node<'on_disk> {
pub(super) fn state(&self) -> Option<EntryState> { pub(super) fn state(&self) -> Option<EntryState> {
self.entry.as_ref().map(|entry| entry.state) self.entry.as_ref().map(|entry| entry.state)
} }
pub(super) fn sorted<'tree>( pub(super) fn sorted<'tree>(
/// `(full_path, entry, copy_source)` /// `(full_path, entry, copy_source)`
type NodeDataMut<'tree, 'on_disk> = ( type NodeDataMut<'tree, 'on_disk> = (
&'tree HgPath, &'tree HgPath,
&'tree mut Option<DirstateEntry>, &'tree mut Option<DirstateEntry>,
&'tree mut Option<Cow<'on_disk, HgPath>>, &'tree mut Option<Cow<'on_disk, HgPath>>,
); );
impl<'on_disk> DirstateMap<'on_disk> { impl<'on_disk> DirstateMap<'on_disk> {
pub(super) fn empty(on_disk: &'on_disk [u8]) -> Self {
Self {
on_disk,
root: ChildNodes::default(),
nodes_with_entry_count: 0,
nodes_with_copy_source_count: 0,
}
}
#[timed] #[timed]
pub fn new_v2( pub fn new_v2(
on_disk: &'on_disk [u8], on_disk: &'on_disk [u8],
) -> Result<(Self, Option<DirstateParents>), DirstateError> { ) -> Result<(Self, Option<DirstateParents>), DirstateError> {
if let Some(rest) = on_disk.drop_prefix(V2_FORMAT_MARKER) { on_disk::read(on_disk)
Self::new_v1(rest)
} else if on_disk.is_empty() {
Self::new_v1(on_disk)
} else {
return Err(HgError::corrupted(
"missing dirstate-v2 magic number",
)
.into());
}
} }
#[timed] #[timed]
pub fn new_v1( pub fn new_v1(
on_disk: &'on_disk [u8], on_disk: &'on_disk [u8],
) -> Result<(Self, Option<DirstateParents>), DirstateError> { ) -> Result<(Self, Option<DirstateParents>), DirstateError> {
let mut map = Self { let mut map = Self::empty(on_disk);
on_disk,
root: ChildNodes::default(),
nodes_with_entry_count: 0,
nodes_with_copy_source_count: 0,
};
if map.on_disk.is_empty() { if map.on_disk.is_empty() {
return Ok((map, None)); return Ok((map, None));
} }
let parents = parse_dirstate_entries( let parents = parse_dirstate_entries(
map.on_disk, map.on_disk,
|path, entry, copy_source| { |path, entry, copy_source| {
let tracked = entry.state.is_tracked(); let tracked = entry.state.is_tracked();
} }
#[timed] #[timed]
fn pack_v2( fn pack_v2(
&mut self, &mut self,
parents: DirstateParents, parents: DirstateParents,
now: Timestamp, now: Timestamp,
) -> Result<Vec<u8>, DirstateError> { ) -> Result<Vec<u8>, DirstateError> {
// Inefficient but temporary on_disk::write(self, parents, now)
let mut v2 = V2_FORMAT_MARKER.to_vec();
v2.append(&mut self.pack_v1(parents, now)?);
Ok(v2)
} }
fn set_all_dirs(&mut self) -> Result<(), DirstateMapError> { fn set_all_dirs(&mut self) -> Result<(), DirstateMapError> {
// Do nothing, this `DirstateMap` does not a separate `all_dirs` that // Do nothing, this `DirstateMap` does not a separate `all_dirs` that
// needs to be recomputed // needs to be recomputed
Ok(()) Ok(())
} }
ignore_files: Vec<PathBuf>, ignore_files: Vec<PathBuf>,
options: StatusOptions, options: StatusOptions,
) -> Result<(DirstateStatus<'a>, Vec<PatternFileWarning>), StatusError> ) -> Result<(DirstateStatus<'a>, Vec<PatternFileWarning>), StatusError>
{ {
super::status::status(self, matcher, root_dir, ignore_files, options) super::status::status(self, matcher, root_dir, ignore_files, options)
} }
fn copy_map_len(&self) -> usize { fn copy_map_len(&self) -> usize {
self.nodes_with_copy_source_count self.nodes_with_copy_source_count as usize
} }
fn copy_map_iter(&self) -> CopyMapIter<'_> { fn copy_map_iter(&self) -> CopyMapIter<'_> {
Box::new(self.iter_nodes().filter_map(|(path, node)| { Box::new(self.iter_nodes().filter_map(|(path, node)| {
node.copy_source node.copy_source
.as_ref() .as_ref()
.map(|copy_source| (path, &**copy_source)) .map(|copy_source| (path, &**copy_source))
})) }))
); );
if node.copy_source.is_none() { if node.copy_source.is_none() {
self.nodes_with_copy_source_count += 1 self.nodes_with_copy_source_count += 1
} }
node.copy_source.replace(value.into()).map(Cow::into_owned) node.copy_source.replace(value.into()).map(Cow::into_owned)
} }
fn len(&self) -> usize { fn len(&self) -> usize {
self.nodes_with_entry_count self.nodes_with_entry_count as usize
} }
fn contains_key(&self, key: &HgPath) -> bool { fn contains_key(&self, key: &HgPath) -> bool {
self.get(key).is_some() self.get(key).is_some()
} }
fn get(&self, key: &HgPath) -> Option<&DirstateEntry> { fn get(&self, key: &HgPath) -> Option<&DirstateEntry> {
self.get_node(key)?.entry.as_ref() self.get_node(key)?.entry.as_ref()
} }
fn iter(&self) -> StateMapIter<'_> { fn iter(&self) -> StateMapIter<'_> {
Box::new(self.iter_nodes().filter_map(|(path, node)| { Box::new(self.iter_nodes().filter_map(|(path, node)| {
node.entry.as_ref().map(|entry| (path, entry)) node.entry.as_ref().map(|entry| (path, entry))
})) }))
} }
} }

rust/hg-core/src/dirstate_tree/on_disk.rs

//! The "version 2" disk representation of the dirstate
//!
//! # File format
//!
//! The file starts with a fixed-sized header, whose layout is defined by the
//! `Header` struct. Its `root` field contains the slice (offset and length) to
//! the nodes representing the files and directories at the root of the
//! repository. Each node is also fixed-size, defined by the `Node` struct.
//! Nodes in turn contain slices to variable-size paths, and to their own child
//! nodes (if any) for nested files and directories.
use crate::dirstate::parsers::clear_ambiguous_mtime;
use crate::dirstate::parsers::Timestamp;
use crate::dirstate_tree::dirstate_map::{self, DirstateMap};
use crate::dirstate_tree::path_with_basename::WithBasename;
use crate::errors::HgError;
use crate::utils::hg_path::HgPath;
use crate::DirstateEntry;
use crate::DirstateError;
use crate::DirstateParents;
use bytes_cast::unaligned::{I32Be, U32Be, U64Be};
use bytes_cast::BytesCast;
use std::borrow::Cow;
use std::convert::{TryFrom, TryInto};
/// Added at the start of `.hg/dirstate` when the "v2" format is used. /// Added at the start of `.hg/dirstate` when the "v2" format is used.
/// Acts like a "magic number". This is a sanity check, not strictly necessary /// This a redundant sanity check more than an actual "magic number" since
/// since `.hg/requires` already governs which format should be used. /// `.hg/requires` already governs which format should be used.
pub const V2_FORMAT_MARKER: &[u8; 12] = b"dirstate-v2\n"; pub const V2_FORMAT_MARKER: &[u8; 12] = b"dirstate-v2\n";
#[derive(BytesCast)]
#[repr(C)]
struct Header {
marker: [u8; V2_FORMAT_MARKER.len()],
/// `dirstatemap.parents()` in `mercurial/dirstate.py` relies on this
/// `parents` field being at this offset, immediately after `marker`.
parents: DirstateParents,
root: ChildNodes,
nodes_with_entry_count: Size,
nodes_with_copy_source_count: Size,
}
#[derive(BytesCast)]
#[repr(C)]
struct Node {
full_path: PathSlice,
/// In bytes from `self.full_path.start`
base_name_start: Size,
copy_source: OptPathSlice,
entry: OptEntry,
children: ChildNodes,
tracked_descendants_count: Size,
}
/// Either nothing if `state == b'\0'`, or a dirstate entry like in the v1
/// format
#[derive(BytesCast)]
#[repr(C)]
struct OptEntry {
state: u8,
mode: I32Be,
mtime: I32Be,
size: I32Be,
}
/// Counted in bytes from the start of the file
///
/// NOTE: If we decide to never support `.hg/dirstate` files larger than 4 GiB
/// we could save space by using `U32Be` instead.
type Offset = U64Be;
/// Counted in number of items
///
/// NOTE: not supporting directories with more than 4 billion direct children,
/// or filenames more than 4 GiB.
type Size = U32Be;
/// Location of consecutive, fixed-size items.
///
/// An item can be a single byte for paths, or a struct with
/// `derive(BytesCast)`.
#[derive(BytesCast, Copy, Clone)]
#[repr(C)]
struct Slice {
start: Offset,
len: Size,
}
/// A contiguous sequence of `len` times `Node`, representing the child nodes
/// of either some other node or of the repository root.
///
/// Always sorted by ascending `full_path`, to allow binary search.
/// Since nodes with the same parent nodes also have the same parent path,
/// only the `base_name`s need to be compared during binary search.
type ChildNodes = Slice;
/// A `HgPath` of `len` bytes
type PathSlice = Slice;
/// Either nothing if `start == 0`, or a `HgPath` of `len` bytes
type OptPathSlice = Slice;
/// Make sure that size-affecting changes are made knowingly
fn _static_assert_size_of() {
let _ = std::mem::transmute::<Header, [u8; 72]>;
let _ = std::mem::transmute::<Node, [u8; 57]>;
}
pub(super) fn read<'on_disk>(
on_disk: &'on_disk [u8],
) -> Result<(DirstateMap<'on_disk>, Option<DirstateParents>), DirstateError> {
if on_disk.is_empty() {
return Ok((DirstateMap::empty(on_disk), None));
}
let (header, _) = Header::from_bytes(on_disk)
.map_err(|_| HgError::corrupted("truncated dirstate-v2"))?;
let Header {
marker,
parents,
root,
nodes_with_entry_count,
nodes_with_copy_source_count,
} = header;
if marker != V2_FORMAT_MARKER {
return Err(HgError::corrupted("missing dirstated-v2 marker").into());
}
let dirstate_map = DirstateMap {
on_disk,
root: read_nodes(on_disk, *root)?,
nodes_with_entry_count: nodes_with_entry_count.get(),
nodes_with_copy_source_count: nodes_with_copy_source_count.get(),
};
let parents = Some(parents.clone());
Ok((dirstate_map, parents))
}
impl Node {
pub(super) fn path<'on_disk>(
&self,
on_disk: &'on_disk [u8],
) -> Result<dirstate_map::NodeKey<'on_disk>, HgError> {
let full_path = read_hg_path(on_disk, self.full_path)?;
let base_name_start = usize::try_from(self.base_name_start.get())
// u32 -> usize, could only panic on a 16-bit CPU
.expect("dirstate-v2 base_name_start out of bounds");
if base_name_start < full_path.len() {
Ok(WithBasename::from_raw_parts(full_path, base_name_start))
} else {
Err(HgError::corrupted(
"dirstate-v2 base_name_start out of bounds",
))
}
}
pub(super) fn copy_source<'on_disk>(
&self,
on_disk: &'on_disk [u8],
) -> Result<Option<Cow<'on_disk, HgPath>>, HgError> {
Ok(if self.copy_source.start.get() != 0 {
Some(read_hg_path(on_disk, self.copy_source)?)
} else {
None
})
}
pub(super) fn entry(&self) -> Result<Option<DirstateEntry>, HgError> {
Ok(if self.entry.state != b'\0' {
Some(DirstateEntry {
state: self.entry.state.try_into()?,
mode: self.entry.mode.get(),
mtime: self.entry.mtime.get(),
size: self.entry.size.get(),
})
} else {
None
})
}
pub(super) fn to_in_memory_node<'on_disk>(
&self,
on_disk: &'on_disk [u8],
) -> Result<dirstate_map::Node<'on_disk>, HgError> {
Ok(dirstate_map::Node {
children: read_nodes(on_disk, self.children)?,
copy_source: self.copy_source(on_disk)?,
entry: self.entry()?,
tracked_descendants_count: self.tracked_descendants_count.get(),
})
}
}
fn read_nodes(
on_disk: &[u8],
slice: ChildNodes,
) -> Result<dirstate_map::ChildNodes, HgError> {
read_slice::<Node>(on_disk, slice)?
.iter()
.map(|node| {
Ok((node.path(on_disk)?, node.to_in_memory_node(on_disk)?))
})
.collect()
}
fn read_hg_path(on_disk: &[u8], slice: Slice) -> Result<Cow<HgPath>, HgError> {
let bytes = read_slice::<u8>(on_disk, slice)?;
Ok(Cow::Borrowed(HgPath::new(bytes)))
}
fn read_slice<T>(on_disk: &[u8], slice: Slice) -> Result<&[T], HgError>
where
T: BytesCast,
{
// Either `usize::MAX` would result in "out of bounds" error since a single
// `&[u8]` cannot occupy the entire addess space.
let start = usize::try_from(slice.start.get()).unwrap_or(std::usize::MAX);
let len = usize::try_from(slice.len.get()).unwrap_or(std::usize::MAX);
on_disk
.get(start..)
.and_then(|bytes| T::slice_from_bytes(bytes, len).ok())
.map(|(slice, _rest)| slice)
.ok_or_else(|| {
HgError::corrupted("dirstate v2 slice is out of bounds")
})
}
pub(super) fn write(
dirstate_map: &mut DirstateMap,
parents: DirstateParents,
now: Timestamp,
) -> Result<Vec<u8>, DirstateError> {
// TODO:!how do we want to handle this in 2038?
let now: i32 = now.0.try_into().expect("time overflow");
let header_len = std::mem::size_of::<Header>();
// This ignores the space for paths, and for nodes without an entry.
// TODO: better estimate? Skip the `Vec` and write to a file directly?
AlphareUnsubmitted
Not Done

This will be done differently when we move to an append-only format anyway, no need to worry about it.

Alphare: This will be done differently when we move to an append-only format anyway, no need to worry…
let size_guess = header_len
+ std::mem::size_of::<Node>()
* dirstate_map.nodes_with_entry_count as usize;
let mut out = Vec::with_capacity(size_guess);
// Keep space for the header. We’ll fill it out at the end when we know the
// actual offset for the root nodes.
out.resize(header_len, 0_u8);
let root = write_nodes(&mut dirstate_map.root, now, &mut out)?;
let header = Header {
marker: *V2_FORMAT_MARKER,
parents: parents,
root,
nodes_with_entry_count: dirstate_map.nodes_with_entry_count.into(),
nodes_with_copy_source_count: dirstate_map
.nodes_with_copy_source_count
.into(),
};
out[..header_len].copy_from_slice(header.as_bytes());
Ok(out)
}
/// Serialize the dirstate to the `v2` format after clearing ambigous `mtime`s.
fn write_nodes(
nodes: &mut dirstate_map::ChildNodes,
now: i32,
out: &mut Vec<u8>,
) -> Result<ChildNodes, DirstateError> {
// `dirstate_map::ChildNodes` is a `HashMap` with undefined iteration
// order. Sort to enable binary search in the written file.
let nodes = dirstate_map::Node::sorted(nodes);
// First accumulate serialized nodes in a `Vec`
let mut on_disk_nodes = Vec::with_capacity(nodes.len());
for (full_path, node) in nodes {
on_disk_nodes.push(Node {
children: write_nodes(&mut node.children, now, out)?,
tracked_descendants_count: node.tracked_descendants_count.into(),
full_path: write_slice::<u8>(
full_path.full_path().as_bytes(),
out,
),
base_name_start: u32::try_from(full_path.base_name_start())
// Could only panic for paths over 4 GiB
.expect("dirstate-v2 offset overflow")
.into(),
copy_source: if let Some(source) = &node.copy_source {
write_slice::<u8>(source.as_bytes(), out)
} else {
Slice {
start: 0.into(),
len: 0.into(),
}
},
entry: if let Some(entry) = &mut node.entry {
clear_ambiguous_mtime(entry, now);
OptEntry {
state: entry.state.into(),
mode: entry.mode.into(),
mtime: entry.mtime.into(),
size: entry.size.into(),
}
} else {
OptEntry {
state: b'\0',
mode: 0.into(),
mtime: 0.into(),
size: 0.into(),
}
},
})
}
// … so we can write them contiguously
Ok(write_slice::<Node>(&on_disk_nodes, out))
}
fn write_slice<T>(slice: &[T], out: &mut Vec<u8>) -> Slice
where
T: BytesCast,
{
let start = u64::try_from(out.len())
// Could only panic on a 128-bit CPU with a dirstate over 16 EiB
.expect("dirstate-v2 offset overflow")
.into();
let len = u32::try_from(slice.len())
// Could only panic for paths over 4 GiB or nodes with over 4 billions
// child nodes
.expect("dirstate-v2 offset overflow")
.into();
out.extend(slice.as_bytes());
Slice { start, len }
}

rust/hg-core/src/dirstate_tree/path_with_basename.rs

} }
impl<T> WithBasename<T> { impl<T> WithBasename<T> {
pub fn full_path(&self) -> &T { pub fn full_path(&self) -> &T {
&self.full_path &self.full_path
} }
} }
impl<T: AsRef<HgPath>> WithBasename<T> { fn find_base_name_start(full_path: &HgPath) -> usize {
pub fn new(full_path: T) -> Self { if let Some(last_slash_position) =
let base_name_start = if let Some(last_slash_position) = full_path full_path.as_bytes().iter().rposition(|&byte| byte == b'/')
.as_ref()
.as_bytes()
.iter()
.rposition(|&byte| byte == b'/')
{ {
last_slash_position + 1 last_slash_position + 1
} else { } else {
0 0
}; }
}
impl<T: AsRef<HgPath>> WithBasename<T> {
pub fn new(full_path: T) -> Self {
Self {
base_name_start: find_base_name_start(full_path.as_ref()),
full_path,
}
}
pub fn from_raw_parts(full_path: T, base_name_start: usize) -> Self {
debug_assert_eq!(
base_name_start,
find_base_name_start(full_path.as_ref())
);
Self { Self {
base_name_start, base_name_start,
full_path, full_path,
} }
} }
pub fn base_name(&self) -> &HgPath { pub fn base_name(&self) -> &HgPath {
HgPath::new( HgPath::new(
&self.full_path.as_ref().as_bytes()[self.base_name_start..], &self.full_path.as_ref().as_bytes()[self.base_name_start..],
) )
} }
pub fn base_name_start(&self) -> usize {
self.base_name_start
}
} }
impl<T: AsRef<HgPath>> Borrow<HgPath> for WithBasename<T> { impl<T: AsRef<HgPath>> Borrow<HgPath> for WithBasename<T> {
fn borrow(&self) -> &HgPath { fn borrow(&self) -> &HgPath {
self.base_name() self.base_name()
} }
} }