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use std::borrow::Cow;
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use std::convert::TryFrom;
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use std::io::Read;
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use std::ops::Deref;
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use std::path::Path;
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use flate2::read::ZlibDecoder;
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use micro_timer::timed;
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use sha1::{Digest, Sha1};
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use zstd;
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use super::index::Index;
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use super::node::{NodePrefix, NODE_BYTES_LENGTH, NULL_NODE};
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use super::nodemap;
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use super::nodemap::{NodeMap, NodeMapError};
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use super::nodemap_docket::NodeMapDocket;
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use super::patch;
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use crate::errors::HgError;
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use crate::repo::Repo;
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use crate::revlog::Revision;
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use crate::{Node, NULL_REVISION};
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const REVISION_FLAG_CENSORED: u16 = 1 << 15;
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const REVISION_FLAG_ELLIPSIS: u16 = 1 << 14;
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const REVISION_FLAG_EXTSTORED: u16 = 1 << 13;
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const REVISION_FLAG_HASCOPIESINFO: u16 = 1 << 12;
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// Keep this in sync with REVIDX_KNOWN_FLAGS in
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// mercurial/revlogutils/flagutil.py
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const REVIDX_KNOWN_FLAGS: u16 = REVISION_FLAG_CENSORED
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| REVISION_FLAG_ELLIPSIS
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| REVISION_FLAG_EXTSTORED
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| REVISION_FLAG_HASCOPIESINFO;
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#[derive(derive_more::From)]
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pub enum RevlogError {
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InvalidRevision,
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/// Working directory is not supported
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WDirUnsupported,
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/// Found more than one entry whose ID match the requested prefix
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AmbiguousPrefix,
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#[from]
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Other(HgError),
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}
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impl From<NodeMapError> for RevlogError {
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fn from(error: NodeMapError) -> Self {
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match error {
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NodeMapError::MultipleResults => RevlogError::AmbiguousPrefix,
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NodeMapError::RevisionNotInIndex(_) => RevlogError::corrupted(),
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}
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}
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}
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fn corrupted() -> HgError {
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HgError::corrupted("corrupted revlog")
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}
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impl RevlogError {
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fn corrupted() -> Self {
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RevlogError::Other(corrupted())
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}
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}
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/// Read only implementation of revlog.
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pub struct Revlog {
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/// When index and data are not interleaved: bytes of the revlog index.
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/// When index and data are interleaved: bytes of the revlog index and
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/// data.
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index: Index,
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/// When index and data are not interleaved: bytes of the revlog data
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data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>>,
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/// When present on disk: the persistent nodemap for this revlog
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nodemap: Option<nodemap::NodeTree>,
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}
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impl Revlog {
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/// Open a revlog index file.
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///
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/// It will also open the associated data file if index and data are not
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/// interleaved.
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#[timed]
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pub fn open(
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repo: &Repo,
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index_path: impl AsRef<Path>,
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data_path: Option<&Path>,
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) -> Result<Self, HgError> {
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let index_path = index_path.as_ref();
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let index = {
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match repo.store_vfs().mmap_open_opt(&index_path)? {
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None => Index::new(Box::new(vec![])),
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Some(index_mmap) => {
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let index = Index::new(Box::new(index_mmap))?;
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Ok(index)
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}
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}
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}?;
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let default_data_path = index_path.with_extension("d");
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// type annotation required
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// won't recognize Mmap as Deref<Target = [u8]>
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let data_bytes: Option<Box<dyn Deref<Target = [u8]> + Send>> =
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if index.is_inline() {
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None
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} else {
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let data_path = data_path.unwrap_or(&default_data_path);
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let data_mmap = repo.store_vfs().mmap_open(data_path)?;
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Some(Box::new(data_mmap))
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};
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let nodemap = if index.is_inline() {
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None
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} else {
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NodeMapDocket::read_from_file(repo, index_path)?.map(
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|(docket, data)| {
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nodemap::NodeTree::load_bytes(
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Box::new(data),
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docket.data_length,
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)
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},
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)
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};
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Ok(Revlog {
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index,
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data_bytes,
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nodemap,
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})
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}
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/// Return number of entries of the `Revlog`.
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pub fn len(&self) -> usize {
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self.index.len()
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}
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/// Returns `true` if the `Revlog` has zero `entries`.
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pub fn is_empty(&self) -> bool {
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self.index.is_empty()
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}
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/// Returns the node ID for the given revision number, if it exists in this
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/// revlog
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pub fn node_from_rev(&self, rev: Revision) -> Option<&Node> {
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if rev == NULL_REVISION {
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return Some(&NULL_NODE);
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}
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Some(self.index.get_entry(rev)?.hash())
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}
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/// Return the revision number for the given node ID, if it exists in this
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/// revlog
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#[timed]
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pub fn rev_from_node(
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&self,
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node: NodePrefix,
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) -> Result<Revision, RevlogError> {
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if node.is_prefix_of(&NULL_NODE) {
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return Ok(NULL_REVISION);
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}
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if let Some(nodemap) = &self.nodemap {
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return nodemap
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.find_bin(&self.index, node)?
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.ok_or(RevlogError::InvalidRevision);
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}
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// Fallback to linear scan when a persistent nodemap is not present.
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// This happens when the persistent-nodemap experimental feature is not
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// enabled, or for small revlogs.
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//
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// TODO: consider building a non-persistent nodemap in memory to
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// optimize these cases.
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let mut found_by_prefix = None;
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for rev in (0..self.len() as Revision).rev() {
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let index_entry =
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self.index.get_entry(rev).ok_or(HgError::corrupted(
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|
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"revlog references a revision not in the index",
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))?;
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if node == *index_entry.hash() {
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return Ok(rev);
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}
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if node.is_prefix_of(index_entry.hash()) {
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if found_by_prefix.is_some() {
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return Err(RevlogError::AmbiguousPrefix);
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}
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found_by_prefix = Some(rev)
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}
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}
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found_by_prefix.ok_or(RevlogError::InvalidRevision)
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}
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/// Returns whether the given revision exists in this revlog.
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pub fn has_rev(&self, rev: Revision) -> bool {
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self.index.get_entry(rev).is_some()
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}
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/// Return the full data associated to a revision.
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///
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/// All entries required to build the final data out of deltas will be
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/// retrieved as needed, and the deltas will be applied to the inital
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/// snapshot to rebuild the final data.
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#[timed]
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pub fn get_rev_data(
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&self,
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rev: Revision,
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) -> Result<Cow<[u8]>, RevlogError> {
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if rev == NULL_REVISION {
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return Ok(Cow::Borrowed(&[]));
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};
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Ok(self.get_entry(rev)?.data()?)
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}
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/// Check the hash of some given data against the recorded hash.
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pub fn check_hash(
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&self,
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p1: Revision,
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p2: Revision,
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expected: &[u8],
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data: &[u8],
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) -> bool {
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let e1 = self.index.get_entry(p1);
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let h1 = match e1 {
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Some(ref entry) => entry.hash(),
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None => &NULL_NODE,
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};
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let e2 = self.index.get_entry(p2);
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let h2 = match e2 {
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Some(ref entry) => entry.hash(),
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None => &NULL_NODE,
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};
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&hash(data, h1.as_bytes(), h2.as_bytes()) == expected
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}
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|
|
|
/// Build the full data of a revision out its snapshot
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|
|
/// and its deltas.
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|
|
#[timed]
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|
|
fn build_data_from_deltas(
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|
|
snapshot: RevlogEntry,
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|
deltas: &[RevlogEntry],
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|
) -> Result<Vec<u8>, HgError> {
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|
|
let snapshot = snapshot.data_chunk()?;
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|
|
let deltas = deltas
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|
|
.iter()
|
|
|
.rev()
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|
|
.map(RevlogEntry::data_chunk)
|
|
|
.collect::<Result<Vec<_>, _>>()?;
|
|
|
let patches: Vec<_> =
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|
|
deltas.iter().map(|d| patch::PatchList::new(d)).collect();
|
|
|
let patch = patch::fold_patch_lists(&patches);
|
|
|
Ok(patch.apply(&snapshot))
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|
|
}
|
|
|
|
|
|
/// Return the revlog data.
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|
|
fn data(&self) -> &[u8] {
|
|
|
match self.data_bytes {
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|
|
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.
|
|
|
pub 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() as usize;
|
|
|
let data = if self.index.is_inline() {
|
|
|
self.index.data(start, end)
|
|
|
} else {
|
|
|
&self.data()[start..end]
|
|
|
};
|
|
|
let entry = RevlogEntry {
|
|
|
revlog: self,
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|
|
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())
|
|
|
},
|
|
|
p1: index_entry.p1(),
|
|
|
p2: index_entry.p2(),
|
|
|
flags: index_entry.flags(),
|
|
|
hash: *index_entry.hash(),
|
|
|
};
|
|
|
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, HgError> {
|
|
|
return self.get_entry(rev).map_err(|_| corrupted());
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// The revlog entry's bytes and the necessary informations to extract
|
|
|
/// the entry's data.
|
|
|
#[derive(Clone)]
|
|
|
pub struct RevlogEntry<'a> {
|
|
|
revlog: &'a Revlog,
|
|
|
rev: Revision,
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|
|
bytes: &'a [u8],
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|
|
compressed_len: u32,
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|
|
uncompressed_len: i32,
|
|
|
base_rev_or_base_of_delta_chain: Option<Revision>,
|
|
|
p1: Revision,
|
|
|
p2: Revision,
|
|
|
flags: u16,
|
|
|
hash: Node,
|
|
|
}
|
|
|
|
|
|
impl<'a> RevlogEntry<'a> {
|
|
|
pub fn revision(&self) -> Revision {
|
|
|
self.rev
|
|
|
}
|
|
|
|
|
|
pub fn uncompressed_len(&self) -> Option<u32> {
|
|
|
u32::try_from(self.uncompressed_len).ok()
|
|
|
}
|
|
|
|
|
|
pub fn has_p1(&self) -> bool {
|
|
|
self.p1 != NULL_REVISION
|
|
|
}
|
|
|
|
|
|
pub fn is_cencored(&self) -> bool {
|
|
|
(self.flags & REVISION_FLAG_CENSORED) != 0
|
|
|
}
|
|
|
|
|
|
pub fn has_length_affecting_flag_processor(&self) -> bool {
|
|
|
// Relevant Python code: revlog.size()
|
|
|
// note: ELLIPSIS is known to not change the content
|
|
|
(self.flags & (REVIDX_KNOWN_FLAGS ^ REVISION_FLAG_ELLIPSIS)) != 0
|
|
|
}
|
|
|
|
|
|
/// The data for this entry, after resolving deltas if any.
|
|
|
pub fn data(&self) -> Result<Cow<'a, [u8]>, HgError> {
|
|
|
let mut entry = self.clone();
|
|
|
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.revlog.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.revlog.get_entry_internal(base_rev)?;
|
|
|
}
|
|
|
|
|
|
let data = if delta_chain.is_empty() {
|
|
|
entry.data_chunk()?
|
|
|
} else {
|
|
|
Revlog::build_data_from_deltas(entry, &delta_chain)?.into()
|
|
|
};
|
|
|
|
|
|
if self.revlog.check_hash(
|
|
|
self.p1,
|
|
|
self.p2,
|
|
|
self.hash.as_bytes(),
|
|
|
&data,
|
|
|
) {
|
|
|
Ok(data)
|
|
|
} else {
|
|
|
Err(corrupted())
|
|
|
}
|
|
|
}
|
|
|
|
|
|
/// Extract the data contained in the entry.
|
|
|
/// This may be a delta. (See `is_delta`.)
|
|
|
fn data_chunk(&self) -> Result<Cow<'a, [u8]>, HgError> {
|
|
|
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(corrupted()),
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn uncompressed_zlib_data(&self) -> Result<Vec<u8>, HgError> {
|
|
|
let mut decoder = ZlibDecoder::new(self.bytes);
|
|
|
if self.is_delta() {
|
|
|
let mut buf = Vec::with_capacity(self.compressed_len as usize);
|
|
|
decoder.read_to_end(&mut buf).map_err(|_| corrupted())?;
|
|
|
Ok(buf)
|
|
|
} else {
|
|
|
let cap = self.uncompressed_len.max(0) as usize;
|
|
|
let mut buf = vec![0; cap];
|
|
|
decoder.read_exact(&mut buf).map_err(|_| corrupted())?;
|
|
|
Ok(buf)
|
|
|
}
|
|
|
}
|
|
|
|
|
|
fn uncompressed_zstd_data(&self) -> Result<Vec<u8>, HgError> {
|
|
|
if self.is_delta() {
|
|
|
let mut buf = Vec::with_capacity(self.compressed_len as usize);
|
|
|
zstd::stream::copy_decode(self.bytes, &mut buf)
|
|
|
.map_err(|_| corrupted())?;
|
|
|
Ok(buf)
|
|
|
} else {
|
|
|
let cap = self.uncompressed_len.max(0) as usize;
|
|
|
let mut buf = vec![0; cap];
|
|
|
let len = zstd::block::decompress_to_buffer(self.bytes, &mut buf)
|
|
|
.map_err(|_| corrupted())?;
|
|
|
if len != self.uncompressed_len as usize {
|
|
|
Err(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()
|
|
|
}
|
|
|
|
