use crate::store_impl::packed;impl AsRef<[u8]> for packed::Buffer { fn as_ref(&self) -> &[u8] { &self.data.as_ref()[self.offset..] }}impl AsRef<[u8]> for packed::Backing { fn as_ref(&self) -> &[u8] { match self { packed::Backing::InMemory(data) => data, packed::Backing::Mapped(map) => map, } }}///pub mod open { use std::path::PathBuf; use winnow::{prelude::*, stream::Offset}; use crate::store_impl::packed; /// Initialization impl packed::Buffer { fn open_with_backing(backing: packed::Backing, path: PathBuf) -> Result<Self, Error> { let (backing, offset) = { let (offset, sorted) = { let mut input = backing.as_ref(); if *input.first().unwrap_or(&b' ') == b'#' { let header = packed::decode::header::<()> .parse_next(&mut input) .map_err(|_| Error::HeaderParsing)?; let offset = input.offset_from(&backing.as_ref()); (offset, header.sorted) } else { (0, false) } }; if !sorted { // this implementation is likely slower than what git does, but it's less code, too. let mut entries = packed::Iter::new(&backing.as_ref()[offset..])?.collect::<Result<Vec<_>, _>>()?; entries.sort_by_key(|e| e.name.as_bstr()); let mut serialized = Vec::<u8>::new(); for entry in entries { serialized.extend_from_slice(entry.target); serialized.push(b' '); serialized.extend_from_slice(entry.name.as_bstr()); serialized.push(b'\n'); if let Some(object) = entry.object { serialized.push(b'^'); serialized.extend_from_slice(object); serialized.push(b'\n'); } } (Backing::InMemory(serialized), 0) } else { (backing, offset) } }; Ok(packed::Buffer { offset, data: backing, path, }) } /// Open the file at `path` and map it into memory if the file size is larger than `use_memory_map_if_larger_than_bytes`. /// /// In order to allow fast lookups and optimizations, the contents of the packed refs must be sorted. /// If that's not the case, they will be sorted on the fly with the data being written into a memory buffer. pub fn open(path: PathBuf, use_memory_map_if_larger_than_bytes: u64) -> Result<Self, Error> { let backing = if std::fs::metadata(&path)?.len() <= use_memory_map_if_larger_than_bytes { packed::Backing::InMemory(std::fs::read(&path)?) } else { packed::Backing::Mapped( // SAFETY: we have to take the risk of somebody changing the file underneath. Git never writes into the same file. #[allow(unsafe_code)] unsafe { memmap2::MmapOptions::new().map_copy_read_only(&std::fs::File::open(&path)?)? }, ) }; Self::open_with_backing(backing, path) } /// Open a buffer from `bytes`, which is the content of a typical `packed-refs` file. /// /// In order to allow fast lookups and optimizations, the contents of the packed refs must be sorted. /// If that's not the case, they will be sorted on the fly. pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> { let backing = packed::Backing::InMemory(bytes.into()); Self::open_with_backing(backing, PathBuf::from("<memory>")) } } mod error { use crate::packed; /// The error returned by [`open()`][super::packed::Buffer::open()]. #[derive(Debug, thiserror::Error)] #[allow(missing_docs)] pub enum Error { #[error("The packed-refs file did not have a header or wasn't sorted and could not be iterated")] Iter(#[from] packed::iter::Error), #[error("The header could not be parsed, even though first line started with '#'")] HeaderParsing, #[error("The buffer could not be opened or read")] Io(#[from] std::io::Error), } } pub use error::Error; use crate::packed::Backing;}
use crate::store_impl::packed;
impl AsRef<[u8]> for packed::Buffer {
fn as_ref(&self) -> &[u8] {
&self.data.as_ref()[self.offset..]
}
}
impl AsRef<[u8]> for packed::Backing {
fn as_ref(&self) -> &[u8] {
match self {
packed::Backing::InMemory(data) => data,
packed::Backing::Mapped(map) => map,
}
}
}
///
pub mod open {
use std::path::PathBuf;
use winnow::{prelude::*, stream::Offset};
use crate::store_impl::packed;
/// Initialization
impl packed::Buffer {
fn open_with_backing(backing: packed::Backing, path: PathBuf) -> Result<Self, Error> {
let (backing, offset) = {
let (offset, sorted) = {
let mut input = backing.as_ref();
if *input.first().unwrap_or(&b' ') == b'#' {
let header = packed::decode::header::<()>
.parse_next(&mut input)
.map_err(|_| Error::HeaderParsing)?;
let offset = input.offset_from(&backing.as_ref());
(offset, header.sorted)
} else {
(0, false)
}
};
if !sorted {
// this implementation is likely slower than what git does, but it's less code, too.
let mut entries = packed::Iter::new(&backing.as_ref()[offset..])?.collect::<Result<Vec<_>, _>>()?;
entries.sort_by_key(|e| e.name.as_bstr());
let mut serialized = Vec::<u8>::new();
for entry in entries {
serialized.extend_from_slice(entry.target);
serialized.push(b' ');
serialized.extend_from_slice(entry.name.as_bstr());
serialized.push(b'\n');
if let Some(object) = entry.object {
serialized.push(b'^');
serialized.extend_from_slice(object);
serialized.push(b'\n');
}
}
(Backing::InMemory(serialized), 0)
} else {
(backing, offset)
}
};
Ok(packed::Buffer {
offset,
data: backing,
path,
})
}
/// Open the file at `path` and map it into memory if the file size is larger than `use_memory_map_if_larger_than_bytes`.
///
/// In order to allow fast lookups and optimizations, the contents of the packed refs must be sorted.
/// If that's not the case, they will be sorted on the fly with the data being written into a memory buffer.
pub fn open(path: PathBuf, use_memory_map_if_larger_than_bytes: u64) -> Result<Self, Error> {
let backing = if std::fs::metadata(&path)?.len() <= use_memory_map_if_larger_than_bytes {
packed::Backing::InMemory(std::fs::read(&path)?)
} else {
packed::Backing::Mapped(
// SAFETY: we have to take the risk of somebody changing the file underneath. Git never writes into the same file.
#[allow(unsafe_code)]
unsafe {
memmap2::MmapOptions::new().map_copy_read_only(&std::fs::File::open(&path)?)?
},
)
};
Self::open_with_backing(backing, path)
}
/// Open a buffer from `bytes`, which is the content of a typical `packed-refs` file.
///
/// In order to allow fast lookups and optimizations, the contents of the packed refs must be sorted.
/// If that's not the case, they will be sorted on the fly.
pub fn from_bytes(bytes: &[u8]) -> Result<Self, Error> {
let backing = packed::Backing::InMemory(bytes.into());
Self::open_with_backing(backing, PathBuf::from("<memory>"))
}
}
mod error {
use crate::packed;
/// The error returned by [`open()`][super::packed::Buffer::open()].
#[derive(Debug, thiserror::Error)]
#[allow(missing_docs)]
pub enum Error {
#[error("The packed-refs file did not have a header or wasn't sorted and could not be iterated")]
Iter(#[from] packed::iter::Error),
#[error("The header could not be parsed, even though first line started with '#'")]
HeaderParsing,
#[error("The buffer could not be opened or read")]
Io(#[from] std::io::Error),
}
}
pub use error::Error;
use crate::packed::Backing;
}