|
|
use std::borrow::Cow;
|
|
|
use std::fs::File;
|
|
|
use std::io::Read;
|
|
|
use std::ops::Deref;
|
|
|
use std::path::Path;
|
|
|
|
|
|
use byteorder::{BigEndian, ByteOrder};
|
|
|
use crypto::digest::Digest;
|
|
|
use crypto::sha1::Sha1;
|
|
|
use flate2::read::ZlibDecoder;
|
|
|
use memmap::{Mmap, MmapOptions};
|
|
|
use micro_timer::timed;
|
|
|
use zstd;
|
|
|
|
|
|
use super::index::Index;
|
|
|
use super::node::{NODE_BYTES_LENGTH, NULL_NODE_ID};
|
|
|
use super::patch;
|
|
|
use crate::revlog::Revision;
|
|
|
|
|
|
pub enum RevlogError {
|
|
|
IoError(std::io::Error),
|
|
|
UnsuportedVersion(u16),
|
|
|
InvalidRevision,
|
|
|
Corrupted,
|
|
|
UnknowDataFormat(u8),
|
|
|
}
|
|
|
|
|
|
fn mmap_open(path: &Path) -> Result<Mmap, std::io::Error> {
|
|
|
let file = File::open(path)?;
|
|
|
let mmap = unsafe { MmapOptions::new().map(&file) }?;
|
|
|
Ok(mmap)
|
|
|
}
|
|
|
|
|
|
/// Read only implementation of revlog.
|
|
|
pub struct Revlog {
|
|
|
/// When index and data are not interleaved: bytes of the revlog index.
|
|
|
/// When index and data are interleaved: bytes of the revlog index and
|
|
|
/// data.
|
|
|
index: Index,
|
|
|
/// When index and data are not interleaved: bytes of the revlog data
|
|
|
data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>>,
|
|
|
}
|
|
|
|
|
|
impl Revlog {
|
|
|
/// Open a revlog index file.
|
|
|
///
|
|
|
/// It will also open the associated data file if index and data are not
|
|
|
/// interleaved.
|
|
|
#[timed]
|
|
|
pub fn open(
|
|
|
index_path: &Path,
|
|
|
data_path: Option<&Path>,
|
|
|
) -> Result<Self, RevlogError> {
|
|
|
let index_mmap =
|
|
|
mmap_open(&index_path).map_err(RevlogError::IoError)?;
|
|
|
|
|
|
let version = get_version(&index_mmap);
|
|
|
if version != 1 {
|
|
|
return Err(RevlogError::UnsuportedVersion(version));
|
|
|
}
|
|
|
|
|
|
let index = Index::new(Box::new(index_mmap))?;
|
|
|
|
|
|
let default_data_path = index_path.with_extension("d");
|
|
|
|
|
|
// type annotation required
|
|
|
// won't recognize Mmap as Deref<Target = [u8]>
|
|
|
let data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>> =
|
|
|
if index.is_inline() {
|
|
|
None
|
|
|
} else {
|
|
|
let data_path = data_path.unwrap_or(&default_data_path);
|
|
|
let data_mmap =
|
|
|
mmap_open(data_path).map_err(RevlogError::IoError)?;
|
|
|
Some(Box::new(data_mmap))
|
|
|
};
|
|
|
|
|
|
Ok(Revlog { index, data_bytes })
|
|
|
}
|
|
|
|
|
|
/// Return number of entries of the `Revlog`.
|
|
|
pub fn len(&self) -> usize {
|
|
|
self.index.len()
|
|
|
}
|
|
|
|
|
|
/// Returns `true` if the `Revlog` has zero `entries`.
|
|
|
pub fn is_empty(&self) -> bool {
|
|
|
self.index.is_empty()
|
|
|
}
|
|
|
|
|
|
/// Return the full data associated to a node.
|
|
|
#[timed]
|
|
|
pub fn get_node_rev(&self, node: &[u8]) -> Result<Revision, RevlogError> {
|
|
|
// This is brute force. But it is fast enough for now.
|
|
|
// Optimization will come later.
|
|
|
for rev in (0..self.len() as Revision).rev() {
|
|
|
let index_entry =
|
|
|
self.index.get_entry(rev).ok_or(RevlogError::Corrupted)?;
|
|
|
if node == index_entry.hash() {
|
|
|
return Ok(rev);
|
|
|
}
|
|
|
}
|
|
|
Err(RevlogError::InvalidRevision)
|
|
|
}
|
|
|
|
|
|
/// Return the full data associated to a revision.
|
|
|
///
|
|
|
/// All entries required to build the final data out of deltas will be
|
|
|
/// retrieved as needed, and the deltas will be applied to the inital
|
|
|
/// snapshot to rebuild the final data.
|
|
|
#[timed]
|
|
|
pub fn get_rev_data(&self, rev: Revision) -> Result<Vec<u8>, RevlogError> {
|
|
|
// Todo return -> Cow
|
|
|
let mut entry = self.get_entry(rev)?;
|
|
|
let mut delta_chain = vec![];
|
|
|
while let Some(base_rev) = entry.base_rev {
|
|
|
delta_chain.push(entry);
|
|
|
entry =
|
|
|
self.get_entry(base_rev).or(Err(RevlogError::Corrupted))?;
|
|
|
}
|
|
|
|
|
|
// TODO do not look twice in the index
|
|
|
let index_entry = self
|
|
|
.index
|
|
|
.get_entry(rev)
|
|
|
.ok_or(RevlogError::InvalidRevision)?;
|
|
|
|
|
|
let data: Vec<u8> = if delta_chain.is_empty() {
|
|
|
entry.data()?.into()
|
|
|
} else {
|
|
|
Revlog::build_data_from_deltas(entry, &delta_chain)?
|
|
|
};
|
|
|
|
|
|
if self.check_hash(
|
|
|
index_entry.p1(),
|
|
|
index_entry.p2(),
|
|
|
index_entry.hash(),
|
|
|
&data,
|
|
|
) {
|
|
|
Ok(data)
|
|
|
} else {
|
|
|
Err(RevlogError::Corrupted)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Check the hash of some given data against the recorded hash.
|
|
|
pub fn check_hash(
|
|
|
&self,
|
|
|
p1: Revision,
|
|
|
p2: Revision,
|
|
|
expected: &[u8],
|
|
|
data: &[u8],
|
|
|
) -> bool {
|
|
|
let e1 = self.index.get_entry(p1);
|
|
|
let h1 = match e1 {
|
|
|
Some(ref entry) => entry.hash(),
|
|
|
None => &NULL_NODE_ID,
|
|
|
};
|
|
|
let e2 = self.index.get_entry(p2);
|
|
|
let h2 = match e2 {
|
|
|
Some(ref entry) => entry.hash(),
|
|
|
None => &NULL_NODE_ID,
|
|
|
};
|
|
|
|
|
|
hash(data, &h1, &h2).as_slice() == expected
|
|
|
}
|
|
|
|
|
|
/// Build the full data of a revision out its snapshot
|
|
|
/// and its deltas.
|
|
|
#[timed]
|
|
|
fn build_data_from_deltas(
|
|
|
snapshot: RevlogEntry,
|
|
|
deltas: &[RevlogEntry],
|
|
|
) -> Result<Vec<u8>, RevlogError> {
|
|
|
let snapshot = snapshot.data()?;
|
|
|
let deltas = deltas
|
|
|
.iter()
|
|
|
.rev()
|
|
|
.map(RevlogEntry::data)
|
|
|
.collect::<Result<Vec<Cow<'_, [u8]>>, RevlogError>>()?;
|
|
|
let patches: Vec<_> =
|
|
|
deltas.iter().map(|d| patch::PatchList::new(d)).collect();
|
|
|
let patch = patch::fold_patch_lists(&patches);
|
|
|
Ok(patch.apply(&snapshot))
|
|
|
}
|
|
|
|
|
|
/// Return the revlog data.
|
|
|
fn data(&self) -> &[u8] {
|
|
|
match self.data_bytes {
|
|
|
Some(ref data_bytes) => &data_bytes,
|
|
|
None => panic!(
|
|
|
"forgot to load the data or trying to access inline data"
|
|
|
),
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Get an entry of the revlog.
|
|
|
fn get_entry(&self, rev: Revision) -> Result<RevlogEntry, RevlogError> {
|
|
|
let index_entry = self
|
|
|
.index
|
|
|
.get_entry(rev)
|
|
|
.ok_or(RevlogError::InvalidRevision)?;
|
|
|
let start = index_entry.offset();
|
|
|
let end = start + index_entry.compressed_len();
|
|
|
let data = if self.index.is_inline() {
|
|
|
self.index.data(start, end)
|
|
|
} else {
|
|
|
&self.data()[start..end]
|
|
|
};
|
|
|
let entry = RevlogEntry {
|
|
|
rev,
|
|
|
bytes: data,
|
|
|
compressed_len: index_entry.compressed_len(),
|
|
|
uncompressed_len: index_entry.uncompressed_len(),
|
|
|
base_rev: if index_entry.base_revision() == rev {
|
|
|
None
|
|
|
} else {
|
|
|
Some(index_entry.base_revision())
|
|
|
},
|
|
|
};
|
|
|
Ok(entry)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// The revlog entry's bytes and the necessary informations to extract
|
|
|
/// the entry's data.
|
|
|
#[derive(Debug)]
|
|
|
pub struct RevlogEntry<'a> {
|
|
|
rev: Revision,
|
|
|
bytes: &'a [u8],
|
|
|
compressed_len: usize,
|
|
|
uncompressed_len: usize,
|
|
|
base_rev: Option<Revision>,
|
|
|
}
|
|
|
|
|
|
impl<'a> RevlogEntry<'a> {
|
|
|
/// Extract the data contained in the entry.
|
|
|
pub fn data(&self) -> Result<Cow<'_, [u8]>, RevlogError> {
|
|
|
if self.bytes.is_empty() {
|
|
|
return Ok(Cow::Borrowed(&[]));
|
|
|
}
|
|
|
match self.bytes[0] {
|
|
|
// Revision data is the entirety of the entry, including this
|
|
|
// header.
|
|
|
b'\0' => Ok(Cow::Borrowed(self.bytes)),
|
|
|
// Raw revision data follows.
|
|
|
b'u' => Ok(Cow::Borrowed(&self.bytes[1..])),
|
|
|
// zlib (RFC 1950) data.
|
|
|
b'x' => Ok(Cow::Owned(self.uncompressed_zlib_data()?)),
|
|
|
// zstd data.
|
|
|
b'\x28' => Ok(Cow::Owned(self.uncompressed_zstd_data()?)),
|
|
|
format_type => Err(RevlogError::UnknowDataFormat(format_type)),
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn uncompressed_zlib_data(&self) -> Result<Vec<u8>, RevlogError> {
|
|
|
let mut decoder = ZlibDecoder::new(self.bytes);
|
|
|
if self.is_delta() {
|
|
|
let mut buf = Vec::with_capacity(self.compressed_len);
|
|
|
decoder
|
|
|
.read_to_end(&mut buf)
|
|
|
.or(Err(RevlogError::Corrupted))?;
|
|
|
Ok(buf)
|
|
|
} else {
|
|
|
let mut buf = vec![0; self.uncompressed_len];
|
|
|
decoder
|
|
|
.read_exact(&mut buf)
|
|
|
.or(Err(RevlogError::Corrupted))?;
|
|
|
Ok(buf)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn uncompressed_zstd_data(&self) -> Result<Vec<u8>, RevlogError> {
|
|
|
if self.is_delta() {
|
|
|
let mut buf = Vec::with_capacity(self.compressed_len);
|
|
|
zstd::stream::copy_decode(self.bytes, &mut buf)
|
|
|
.or(Err(RevlogError::Corrupted))?;
|
|
|
Ok(buf)
|
|
|
} else {
|
|
|
let mut buf = vec![0; self.uncompressed_len];
|
|
|
let len = zstd::block::decompress_to_buffer(self.bytes, &mut buf)
|
|
|
.or(Err(RevlogError::Corrupted))?;
|
|
|
if len != self.uncompressed_len {
|
|
|
Err(RevlogError::Corrupted)
|
|
|
} else {
|
|
|
Ok(buf)
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Tell if the entry is a snapshot or a delta
|
|
|
/// (influences on decompression).
|
|
|
fn is_delta(&self) -> bool {
|
|
|
self.base_rev.is_some()
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Format version of the revlog.
|
|
|
pub fn get_version(index_bytes: &[u8]) -> u16 {
|
|
|
BigEndian::read_u16(&index_bytes[2..=3])
|
|
|
}
|
|
|
|
|
|
/// Calculate the hash of a revision given its data and its parents.
|
|
|
fn hash(data: &[u8], p1_hash: &[u8], p2_hash: &[u8]) -> Vec<u8> {
|
|
|
let mut hasher = Sha1::new();
|
|
|
let (a, b) = (p1_hash, p2_hash);
|
|
|
if a > b {
|
|
|
hasher.input(b);
|
|
|
hasher.input(a);
|
|
|
} else {
|
|
|
hasher.input(a);
|
|
|
hasher.input(b);
|
|
|
}
|
|
|
hasher.input(data);
|
|
|
let mut hash = vec![0; NODE_BYTES_LENGTH];
|
|
|
hasher.result(&mut hash);
|
|
|
hash
|
|
|
}
|
|
|
|
|
|
#[cfg(test)]
|
|
|
mod tests {
|
|
|
use super::*;
|
|
|
|
|
|
use super::super::index::IndexEntryBuilder;
|
|
|
|
|
|
#[test]
|
|
|
fn version_test() {
|
|
|
let bytes = IndexEntryBuilder::new()
|
|
|
.is_first(true)
|
|
|
.with_version(1)
|
|
|
.build();
|
|
|
|
|
|
assert_eq!(get_version(&bytes), 1)
|
|
|
}
|
|
|
}
|
|
|
|
