SimonSapin created this revision. Herald added a reviewer: hg-reviewers. Herald added a subscriber: mercurial-patches.
REVISION SUMMARY Such errors when an internal offset or slice length goes out of bounds of the file size, or when an entry state is an invalid byte. Keeping the error zero-size for more layers of function calls and delaying the conversion to a righer error type makes less for for `?` operators to pass around the error value. This will be amplified when we make parsing lazy and many more functions become faillable with this error type. REPOSITORY rHG Mercurial BRANCH default REVISION DETAIL https://phab.mercurial-scm.org/D10748 AFFECTED FILES rust/hg-core/src/dirstate_tree/dirstate_map.rs rust/hg-core/src/dirstate_tree/on_disk.rs CHANGE DETAILS diff --git a/rust/hg-core/src/dirstate_tree/on_disk.rs b/rust/hg-core/src/dirstate_tree/on_disk.rs --- a/rust/hg-core/src/dirstate_tree/on_disk.rs +++ b/rust/hg-core/src/dirstate_tree/on_disk.rs @@ -108,14 +108,32 @@ let _ = std::mem::transmute::<Node, [u8; 57]>; } +/// Unexpected file format found in `.hg/dirstate` with the "v2" format. +pub(crate) struct DirstateV2ParseError; + +impl From<DirstateV2ParseError> for HgError { + fn from(_: DirstateV2ParseError) -> Self { + HgError::corrupted("dirstate-v2 parse error") + } +} + +impl From<DirstateV2ParseError> for crate::DirstateError { + fn from(error: DirstateV2ParseError) -> Self { + HgError::from(error).into() + } +} + pub(super) fn read<'on_disk>( on_disk: &'on_disk [u8], -) -> Result<(DirstateMap<'on_disk>, Option<DirstateParents>), DirstateError> { +) -> Result< + (DirstateMap<'on_disk>, Option<DirstateParents>), + DirstateV2ParseError, +> { if on_disk.is_empty() { return Ok((DirstateMap::empty(on_disk), None)); } - let (header, _) = Header::from_bytes(on_disk) - .map_err(|_| HgError::corrupted("truncated dirstate-v2"))?; + let (header, _) = + Header::from_bytes(on_disk).map_err(|_| DirstateV2ParseError)?; let Header { marker, parents, @@ -124,7 +142,7 @@ nodes_with_copy_source_count, } = header; if marker != V2_FORMAT_MARKER { - return Err(HgError::corrupted("missing dirstated-v2 marker").into()); + return Err(DirstateV2ParseError); } let dirstate_map = DirstateMap { on_disk, @@ -140,7 +158,7 @@ pub(super) fn path<'on_disk>( &self, on_disk: &'on_disk [u8], - ) -> Result<dirstate_map::NodeKey<'on_disk>, HgError> { + ) -> Result<dirstate_map::NodeKey<'on_disk>, DirstateV2ParseError> { let full_path = read_hg_path(on_disk, self.full_path)?; let base_name_start = usize::try_from(self.base_name_start.get()) // u32 -> usize, could only panic on a 16-bit CPU @@ -148,16 +166,14 @@ if base_name_start < full_path.len() { Ok(WithBasename::from_raw_parts(full_path, base_name_start)) } else { - Err(HgError::corrupted( - "dirstate-v2 base_name_start out of bounds", - )) + Err(DirstateV2ParseError) } } pub(super) fn copy_source<'on_disk>( &self, on_disk: &'on_disk [u8], - ) -> Result<Option<Cow<'on_disk, HgPath>>, HgError> { + ) -> Result<Option<Cow<'on_disk, HgPath>>, DirstateV2ParseError> { Ok(if self.copy_source.start.get() != 0 { Some(read_hg_path(on_disk, self.copy_source)?) } else { @@ -165,10 +181,16 @@ }) } - pub(super) fn entry(&self) -> Result<Option<DirstateEntry>, HgError> { + pub(super) fn entry( + &self, + ) -> Result<Option<DirstateEntry>, DirstateV2ParseError> { Ok(if self.entry.state != b'\0' { Some(DirstateEntry { - state: self.entry.state.try_into()?, + state: self + .entry + .state + .try_into() + .map_err(|_| DirstateV2ParseError)?, mode: self.entry.mode.get(), mtime: self.entry.mtime.get(), size: self.entry.size.get(), @@ -181,7 +203,7 @@ pub(super) fn to_in_memory_node<'on_disk>( &self, on_disk: &'on_disk [u8], - ) -> Result<dirstate_map::Node<'on_disk>, HgError> { + ) -> Result<dirstate_map::Node<'on_disk>, DirstateV2ParseError> { Ok(dirstate_map::Node { children: read_nodes(on_disk, self.children)?, copy_source: self.copy_source(on_disk)?, @@ -194,7 +216,7 @@ fn read_nodes( on_disk: &[u8], slice: ChildNodes, -) -> Result<dirstate_map::ChildNodes, HgError> { +) -> Result<dirstate_map::ChildNodes, DirstateV2ParseError> { read_slice::<Node>(on_disk, slice)? .iter() .map(|node| { @@ -204,12 +226,18 @@ .map(dirstate_map::ChildNodes::InMemory) } -fn read_hg_path(on_disk: &[u8], slice: Slice) -> Result<Cow<HgPath>, HgError> { +fn read_hg_path( + on_disk: &[u8], + slice: Slice, +) -> Result<Cow<HgPath>, DirstateV2ParseError> { let bytes = read_slice::<u8>(on_disk, slice)?; Ok(Cow::Borrowed(HgPath::new(bytes))) } -fn read_slice<T>(on_disk: &[u8], slice: Slice) -> Result<&[T], HgError> +fn read_slice<T>( + on_disk: &[u8], + slice: Slice, +) -> Result<&[T], DirstateV2ParseError> where T: BytesCast, { @@ -221,9 +249,7 @@ .get(start..) .and_then(|bytes| T::slice_from_bytes(bytes, len).ok()) .map(|(slice, _rest)| slice) - .ok_or_else(|| { - HgError::corrupted("dirstate v2 slice is out of bounds") - }) + .ok_or_else(|| DirstateV2ParseError) } pub(super) fn write( diff --git a/rust/hg-core/src/dirstate_tree/dirstate_map.rs b/rust/hg-core/src/dirstate_tree/dirstate_map.rs --- a/rust/hg-core/src/dirstate_tree/dirstate_map.rs +++ b/rust/hg-core/src/dirstate_tree/dirstate_map.rs @@ -214,7 +214,7 @@ pub fn new_v2( on_disk: &'on_disk [u8], ) -> Result<(Self, Option<DirstateParents>), DirstateError> { - on_disk::read(on_disk) + Ok(on_disk::read(on_disk)?) } #[timed] To: SimonSapin, #hg-reviewers Cc: mercurial-patches, mercurial-devel _______________________________________________ Mercurial-devel mailing list Mercurial-devel@mercurial-scm.org https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
