|
|
use std::borrow::Cow;
|
|
|
use std::io::Read;
|
|
|
use std::ops::Deref;
|
|
|
use std::path::Path;
|
|
|
|
|
|
use flate2::read::ZlibDecoder;
|
|
|
use micro_timer::timed;
|
|
|
use sha1::{Digest, Sha1};
|
|
|
use zstd;
|
|
|
|
|
|
use super::index::Index;
|
|
|
use super::node::{NodePrefix, NODE_BYTES_LENGTH, NULL_NODE};
|
|
|
use super::nodemap;
|
|
|
use super::nodemap::{NodeMap, NodeMapError};
|
|
|
use super::nodemap_docket::NodeMapDocket;
|
|
|
use super::patch;
|
|
|
use crate::errors::HgError;
|
|
|
use crate::repo::Repo;
|
|
|
use crate::revlog::Revision;
|
|
|
use crate::{Node, NULL_REVISION};
|
|
|
|
|
|
#[derive(derive_more::From)]
|
|
|
pub enum RevlogError {
|
|
|
InvalidRevision,
|
|
|
/// Working directory is not supported
|
|
|
WDirUnsupported,
|
|
|
/// Found more than one entry whose ID match the requested prefix
|
|
|
AmbiguousPrefix,
|
|
|
#[from]
|
|
|
Other(HgError),
|
|
|
}
|
|
|
|
|
|
impl From<NodeMapError> for RevlogError {
|
|
|
fn from(error: NodeMapError) -> Self {
|
|
|
match error {
|
|
|
NodeMapError::MultipleResults => RevlogError::AmbiguousPrefix,
|
|
|
NodeMapError::RevisionNotInIndex(_) => RevlogError::corrupted(),
|
|
|
}
|
|
|
}
|
|
|
}
|
|
|
|
|
|
impl RevlogError {
|
|
|
fn corrupted() -> Self {
|
|
|
RevlogError::Other(HgError::corrupted("corrupted revlog"))
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// 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>>,
|
|
|
/// When present on disk: the persistent nodemap for this revlog
|
|
|
nodemap: Option<nodemap::NodeTree>,
|
|
|
}
|
|
|
|
|
|
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(
|
|
|
repo: &Repo,
|
|
|
index_path: impl AsRef<Path>,
|
|
|
data_path: Option<&Path>,
|
|
|
) -> Result<Self, HgError> {
|
|
|
let index_path = index_path.as_ref();
|
|
|
let index = {
|
|
|
match repo.store_vfs().mmap_open_opt(&index_path)? {
|
|
|
None => Index::new(Box::new(vec![])),
|
|
|
Some(index_mmap) => {
|
|
|
let index = Index::new(Box::new(index_mmap))?;
|
|
|
Ok(index)
|
|
|
}
|
|
|
}
|
|
|
}?;
|
|
|
|
|
|
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 = repo.store_vfs().mmap_open(data_path)?;
|
|
|
Some(Box::new(data_mmap))
|
|
|
};
|
|
|
|
|
|
let nodemap = if index.is_inline() {
|
|
|
None
|
|
|
} else {
|
|
|
NodeMapDocket::read_from_file(repo, index_path)?.map(
|
|
|
|(docket, data)| {
|
|
|
nodemap::NodeTree::load_bytes(
|
|
|
Box::new(data),
|
|
|
docket.data_length,
|
|
|
)
|
|
|
},
|
|
|
)
|
|
|
};
|
|
|
|
|
|
Ok(Revlog {
|
|
|
index,
|
|
|
data_bytes,
|
|
|
nodemap,
|
|
|
})
|
|
|
}
|
|
|
|
|
|
/// 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()
|
|
|
}
|
|
|
|
|
|
/// Returns the node ID for the given revision number, if it exists in this
|
|
|
/// revlog
|
|
|
pub fn node_from_rev(&self, rev: Revision) -> Option<&Node> {
|
|
|
if rev == NULL_REVISION {
|
|
|
return Some(&NULL_NODE);
|
|
|
}
|
|
|
Some(self.index.get_entry(rev)?.hash())
|
|
|
}
|
|
|
|
|
|
/// Return the revision number for the given node ID, if it exists in this
|
|
|
/// revlog
|
|
|
#[timed]
|
|
|
pub fn rev_from_node(
|
|
|
&self,
|
|
|
node: NodePrefix,
|
|
|
) -> Result<Revision, RevlogError> {
|
|
|
if node.is_prefix_of(&NULL_NODE) {
|
|
|
return Ok(NULL_REVISION);
|
|
|
}
|
|
|
|
|
|
if let Some(nodemap) = &self.nodemap {
|
|
|
return nodemap
|
|
|
.find_bin(&self.index, node)?
|
|
|
.ok_or(RevlogError::InvalidRevision);
|
|
|
}
|
|
|
|
|
|
// Fallback to linear scan when a persistent nodemap is not present.
|
|
|
// This happens when the persistent-nodemap experimental feature is not
|
|
|
// enabled, or for small revlogs.
|
|
|
//
|
|
|
// TODO: consider building a non-persistent nodemap in memory to
|
|
|
// optimize these cases.
|
|
|
let mut found_by_prefix = None;
|
|
|
for rev in (0..self.len() as Revision).rev() {
|
|
|
let index_entry =
|
|
|
self.index.get_entry(rev).ok_or(HgError::corrupted(
|
|
|
"revlog references a revision not in the index",
|
|
|
))?;
|
|
|
if node == *index_entry.hash() {
|
|
|
return Ok(rev);
|
|
|
}
|
|
|
if node.is_prefix_of(index_entry.hash()) {
|
|
|
if found_by_prefix.is_some() {
|
|
|
return Err(RevlogError::AmbiguousPrefix);
|
|
|
}
|
|
|
found_by_prefix = Some(rev)
|
|
|
}
|
|
|
}
|
|
|
found_by_prefix.ok_or(RevlogError::InvalidRevision)
|
|
|
}
|
|
|
|
|
|
/// Returns whether the given revision exists in this revlog.
|
|
|
pub fn has_rev(&self, rev: Revision) -> bool {
|
|
|
self.index.get_entry(rev).is_some()
|
|
|
}
|
|
|
|
|
|
/// 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> {
|
|
|
if rev == NULL_REVISION {
|
|
|
return Ok(vec![]);
|
|
|
};
|
|
|
// Todo return -> Cow
|
|
|
let mut entry = self.get_entry(rev)?;
|
|
|
let mut delta_chain = vec![];
|
|
|
|
|
|
// The meaning of `base_rev_or_base_of_delta_chain` depends on
|
|
|
// generaldelta. See the doc on `ENTRY_DELTA_BASE` in
|
|
|
// `mercurial/revlogutils/constants.py` and the code in
|
|
|
// [_chaininfo] and in [index_deltachain].
|
|
|
let uses_generaldelta = self.index.uses_generaldelta();
|
|
|
while let Some(base_rev) = entry.base_rev_or_base_of_delta_chain {
|
|
|
let base_rev = if uses_generaldelta {
|
|
|
base_rev
|
|
|
} else {
|
|
|
entry.rev - 1
|
|
|
};
|
|
|
delta_chain.push(entry);
|
|
|
entry = self.get_entry_internal(base_rev)?;
|
|
|
}
|
|
|
|
|
|
// 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().as_bytes(),
|
|
|
&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,
|
|
|
};
|
|
|
let e2 = self.index.get_entry(p2);
|
|
|
let h2 = match e2 {
|
|
|
Some(ref entry) => entry.hash(),
|
|
|
None => &NULL_NODE,
|
|
|
};
|
|
|
|
|
|
&hash(data, h1.as_bytes(), h2.as_bytes()) == 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_or_base_of_delta_chain: if index_entry
|
|
|
.base_revision_or_base_of_delta_chain()
|
|
|
== rev
|
|
|
{
|
|
|
None
|
|
|
} else {
|
|
|
Some(index_entry.base_revision_or_base_of_delta_chain())
|
|
|
},
|
|
|
};
|
|
|
Ok(entry)
|
|
|
}
|
|
|
|
|
|
/// when resolving internal references within revlog, any errors
|
|
|
/// should be reported as corruption, instead of e.g. "invalid revision"
|
|
|
fn get_entry_internal(
|
|
|
&self,
|
|
|
rev: Revision,
|
|
|
) -> Result<RevlogEntry, RevlogError> {
|
|
|
return self.get_entry(rev).map_err(|_| RevlogError::corrupted());
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// 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_or_base_of_delta_chain: Option<Revision>,
|
|
|
}
|
|
|
|
|
|
impl<'a> RevlogEntry<'a> {
|
|
|
pub fn revision(&self) -> Revision {
|
|
|
self.rev
|
|
|
}
|
|
|
|
|
|
/// 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()?)),
|
|
|
// A proper new format should have had a repo/store requirement.
|
|
|
_format_type => Err(RevlogError::corrupted()),
|
|
|
}
|
|
|
}
|
|
|
|
|
|
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)
|
|
|
.map_err(|_| RevlogError::corrupted())?;
|
|
|
Ok(buf)
|
|
|
} else {
|
|
|
let mut buf = vec![0; self.uncompressed_len];
|
|
|
decoder
|
|
|
.read_exact(&mut buf)
|
|
|
.map_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)
|
|
|
.map_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)
|
|
|
.map_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_or_base_of_delta_chain.is_some()
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Calculate the hash of a revision given its data and its parents.
|
|
|
fn hash(
|
|
|
data: &[u8],
|
|
|
p1_hash: &[u8],
|
|
|
p2_hash: &[u8],
|
|
|
) -> [u8; NODE_BYTES_LENGTH] {
|
|
|
let mut hasher = Sha1::new();
|
|
|
let (a, b) = (p1_hash, p2_hash);
|
|
|
if a > b {
|
|
|
hasher.update(b);
|
|
|
hasher.update(a);
|
|
|
} else {
|
|
|
hasher.update(a);
|
|
|
hasher.update(b);
|
|
|
}
|
|
|
hasher.update(data);
|
|
|
*hasher.finalize().as_ref()
|
|
|
}
|
|
|
|
