hg-core: use `.or(Err(Error))` not `.map_err(|_| Error)` (D9100#inline-15067)

Differential Revision: https://phab.mercurial-scm.org/D9108

rust/hg-core/src/operations/list_tracked_files.rs

@@ -1,188 +1,187 b''
 // list_tracked_files.rs
 //
 // Copyright 2020 Antoine Cezar <[e-mail]>
 //
 // This software may be used and distributed according to the terms of the
 // GNU General Public License version 2 or any later version.
 
 use crate::dirstate::parsers::parse_dirstate;
 use crate::revlog::changelog::Changelog;
 use crate::revlog::manifest::{Manifest, ManifestEntry};
 use crate::revlog::revlog::RevlogError;
 use crate::revlog::Revision;
 use crate::utils::hg_path::HgPath;
 use crate::{DirstateParseError, EntryState};
 use rayon::prelude::*;
 use std::convert::From;
 use std::fs;
 use std::path::PathBuf;
 
 /// Kind of error encountered by `ListDirstateTrackedFiles`
 #[derive(Debug)]
 pub enum ListDirstateTrackedFilesErrorKind {
     /// Error when reading the `dirstate` file
     IoError(std::io::Error),
     /// Error when parsing the `dirstate` file
     ParseError(DirstateParseError),
 }
 
 /// A `ListDirstateTrackedFiles` error
 #[derive(Debug)]
 pub struct ListDirstateTrackedFilesError {
     /// Kind of error encountered by `ListDirstateTrackedFiles`
     pub kind: ListDirstateTrackedFilesErrorKind,
 }
 
 impl From<ListDirstateTrackedFilesErrorKind>
     for ListDirstateTrackedFilesError
 {
     fn from(kind: ListDirstateTrackedFilesErrorKind) -> Self {
         ListDirstateTrackedFilesError { kind }
     }
 }
 
 impl From<std::io::Error> for ListDirstateTrackedFilesError {
     fn from(err: std::io::Error) -> Self {
         let kind = ListDirstateTrackedFilesErrorKind::IoError(err);
         ListDirstateTrackedFilesError { kind }
     }
 }
 
 /// List files under Mercurial control in the working directory
 /// by reading the dirstate
 pub struct ListDirstateTrackedFiles {
     /// The `dirstate` content.
     content: Vec<u8>,
 }
 
 impl ListDirstateTrackedFiles {
     pub fn new(root: &PathBuf) -> Result<Self, ListDirstateTrackedFilesError> {
         let dirstate = root.join(".hg/dirstate");
         let content = fs::read(&dirstate)?;
         Ok(Self { content })
     }
 
     pub fn run(
         &mut self,
     ) -> Result<Vec<&HgPath>, ListDirstateTrackedFilesError> {
         let (_, entries, _) = parse_dirstate(&self.content)
             .map_err(ListDirstateTrackedFilesErrorKind::ParseError)?;
         let mut files: Vec<&HgPath> = entries
             .into_iter()
             .filter_map(|(path, entry)| match entry.state {
                 EntryState::Removed => None,
                 _ => Some(path),
             })
             .collect();
         files.par_sort_unstable();
         Ok(files)
     }
 }
 
 /// Kind of error encountered by `ListRevTrackedFiles`
 #[derive(Debug)]
 pub enum ListRevTrackedFilesErrorKind {
     /// Error when reading a `revlog` file.
     IoError(std::io::Error),
     /// The revision has not been found.
     InvalidRevision,
     /// A `revlog` file is corrupted.
     CorruptedRevlog,
     /// The `revlog` format version is not supported.
     UnsuportedRevlogVersion(u16),
     /// The `revlog` data format is not supported.
     UnknowRevlogDataFormat(u8),
 }
 
 /// A `ListRevTrackedFiles` error
 #[derive(Debug)]
 pub struct ListRevTrackedFilesError {
     /// Kind of error encountered by `ListRevTrackedFiles`
     pub kind: ListRevTrackedFilesErrorKind,
 }
 
 impl From<ListRevTrackedFilesErrorKind> for ListRevTrackedFilesError {
     fn from(kind: ListRevTrackedFilesErrorKind) -> Self {
         ListRevTrackedFilesError { kind }
     }
 }
 
 impl From<RevlogError> for ListRevTrackedFilesError {
     fn from(err: RevlogError) -> Self {
         match err {
             RevlogError::IoError(err) => {
                 ListRevTrackedFilesErrorKind::IoError(err)
             }
             RevlogError::UnsuportedVersion(version) => {
                 ListRevTrackedFilesErrorKind::UnsuportedRevlogVersion(version)
             }
             RevlogError::InvalidRevision => {
                 ListRevTrackedFilesErrorKind::InvalidRevision
             }
             RevlogError::Corrupted => {
                 ListRevTrackedFilesErrorKind::CorruptedRevlog
             }
             RevlogError::UnknowDataFormat(format) => {
                 ListRevTrackedFilesErrorKind::UnknowRevlogDataFormat(format)
             }
         }
         .into()
     }
 }
 
 /// List files under Mercurial control at a given revision.
 pub struct ListRevTrackedFiles<'a> {
     /// The revision to list the files from.
     rev: &'a str,
     /// The changelog file
     changelog: Changelog,
     /// The manifest file
     manifest: Manifest,
     /// The manifest entry corresponding to the revision.
     ///
     /// Used to hold the owner of the returned references.
     manifest_entry: Option<ManifestEntry>,
 }
 
 impl<'a> ListRevTrackedFiles<'a> {
     pub fn new(
         root: &PathBuf,
         rev: &'a str,
     ) -> Result<Self, ListRevTrackedFilesError> {
         let changelog = Changelog::open(&root)?;
         let manifest = Manifest::open(&root)?;
 
         Ok(Self {
             rev,
             changelog,
             manifest,
             manifest_entry: None,
         })
     }
 
     pub fn run(
         &mut self,
     ) -> Result<impl Iterator<Item = &HgPath>, ListRevTrackedFilesError> {
         let changelog_entry = match self.rev.parse::<Revision>() {
             Ok(rev) => self.changelog.get_rev(rev)?,
             _ => {
-                let changelog_node = hex::decode(&self.rev).map_err(|_| {
-                    ListRevTrackedFilesErrorKind::InvalidRevision
-                })?;
+                let changelog_node = hex::decode(&self.rev)
+                    .or(Err(ListRevTrackedFilesErrorKind::InvalidRevision))?;
                 self.changelog.get_node(&changelog_node)?
             }
         };
         let manifest_node = hex::decode(&changelog_entry.manifest_node()?)
-            .map_err(|_| ListRevTrackedFilesErrorKind::CorruptedRevlog)?;
+            .or(Err(ListRevTrackedFilesErrorKind::CorruptedRevlog))?;
 
         self.manifest_entry = Some(self.manifest.get_node(&manifest_node)?);
 
         if let Some(ref manifest_entry) = self.manifest_entry {
             Ok(manifest_entry.files())
         } else {
             panic!(
                 "manifest entry should have been stored in self.manifest_node to ensure its lifetime since references are returned from it"
             )
         }
     }
 }

rust/hg-core/src/revlog/revlog.rs

@@ -1,332 +1,331 b''
 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) -> 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))?;
 
         // TODO load data only when needed //
         // 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 = index_path.with_extension("d");
                 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)
-                .map_err(|_| RevlogError::Corrupted)?;
+            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)
     }
 }