use crate::index;use git_features::{    parallel,    progress::{self, Progress},};use std::sync::{atomic::AtomicBool, Arc}; ///mod indexed;mod reduce;///pub mod with_lookup;use reduce::Reducer; mod error;pub use error::Error; mod types;pub use types::{Algorithm, Outcome, SafetyCheck}; mod options {    use crate::index::traverse::{Algorithm, SafetyCheck};    use std::sync::{atomic::AtomicBool, Arc};     /// Traversal options for [`traverse()`][crate::index::File::traverse()]    #[derive(Debug, Clone)]    pub struct Options {        /// The algorithm to employ.        pub algorithm: Algorithm,        /// If `Some`, only use the given amount of threads. Otherwise, the amount of threads to use will be selected based on        /// the amount of available logical cores.        pub thread_limit: Option<usize>,        /// The kinds of safety checks to perform.        pub check: SafetyCheck,        /// A flag to indicate whether the algorithm should be interrupted. Will be checked occasionally allow stopping a running        /// computation.        pub should_interrupt: Arc<AtomicBool>,    }     impl Default for Options {        fn default() -> Self {            Self {                algorithm: Algorithm::Lookup,                thread_limit: Default::default(),                check: Default::default(),                should_interrupt: Default::default(),            }        }    }}pub use options::Options; /// Traversal of pack data files using an index fileimpl index::File {    /// Iterate through all _decoded objects_ in the given `pack` and handle them with a `Processor`.    /// The return value is (pack-checksum, [`Outcome`], `progress`), thus the pack traversal will always verify    /// the whole packs checksum to assure it was correct. In case of bit-rod, the operation will abort early without    /// verifying all objects using the [interrupt mechanism][git_features::interrupt] mechanism.    ///    /// # Algorithms    ///    /// Using the [`Options::algorithm`] field one can chose between two algorithms providing different tradeoffs. Both invoke    /// `new_processor()` to create functions receiving decoded objects, their object kind, index entry and a progress instance to provide    /// progress information.    ///    /// * [`Algorithm::DeltaTreeLookup`] builds an index to avoid any unnecessary computation while resolving objects, avoiding    ///   the need for a cache entirely, rendering `new_cache()` unused.    ///   One could also call [`traverse_with_index()`][index::File::traverse_with_index()] directly.    /// * [`Algorithm::Lookup`] uses a cache created by `new_cache()` to avoid having to re-compute all bases of a delta-chain while    ///   decoding objects.    ///   One could also call [`traverse_with_lookup()`][index::File::traverse_with_lookup()] directly.    ///    /// Use [`thread_limit`][Options::thread_limit] to further control parallelism and [`check`][SafetyCheck] to define how much the passed    /// objects shall be verified beforehand.    pub fn traverse<P, C, Processor, E>(        &self,        pack: &crate::data::File,        progress: Option<P>,        new_processor: impl Fn() -> Processor + Send + Sync,        new_cache: impl Fn() -> C + Send + Sync,        Options {            algorithm,            thread_limit,            check,            should_interrupt,        }: Options,    ) -> Result<(git_hash::ObjectId, Outcome, Option<P>), Error<E>>    where        P: Progress,        C: crate::cache::DecodeEntry,        E: std::error::Error + Send + Sync + 'static,        Processor: FnMut(            git_object::Kind,            &[u8],            &index::Entry,            &mut progress::DoOrDiscard<<<P as Progress>::SubProgress as Progress>::SubProgress>,        ) -> Result<(), E>,    {        let progress = progress::DoOrDiscard::from(progress);        match algorithm {            Algorithm::Lookup => self.traverse_with_lookup(                new_processor,                new_cache,                progress,                pack,                with_lookup::Options {                    thread_limit,                    check,                    should_interrupt,                },            ),            Algorithm::DeltaTreeLookup => {                self.traverse_with_index(check, thread_limit, new_processor, progress, pack, should_interrupt)            }        }        .map(|(a, b, p)| (a, b, p.into_inner()))    }     fn possibly_verify<E>(        &self,        pack: &crate::data::File,        check: SafetyCheck,        pack_progress: impl Progress,        index_progress: impl Progress,        should_interrupt: Arc<AtomicBool>,    ) -> Result<git_hash::ObjectId, Error<E>>    where        E: std::error::Error + Send + Sync + 'static,    {        Ok(if check.file_checksum() {            if self.pack_checksum() != pack.checksum() {                return Err(Error::PackMismatch {                    actual: pack.checksum(),                    expected: self.pack_checksum(),                });            }            let (pack_res, id) = parallel::join(                {                    let should_interrupt = Arc::clone(&should_interrupt);                    move || pack.verify_checksum(pack_progress, &should_interrupt)                },                move || self.verify_checksum(index_progress, &should_interrupt),            );            pack_res?;            id?        } else {            self.index_checksum()        })    }     #[allow(clippy::too_many_arguments)]    fn decode_and_process_entry<C, P, E>(        &self,        check: SafetyCheck,        pack: &crate::data::File,        cache: &mut C,        buf: &mut Vec<u8>,        progress: &mut P,        header_buf: &mut [u8; 64],        index_entry: &crate::index::Entry,        processor: &mut impl FnMut(git_object::Kind, &[u8], &index::Entry, &mut P) -> Result<(), E>,    ) -> Result<crate::data::decode_entry::Outcome, Error<E>>    where        C: crate::cache::DecodeEntry,        P: Progress,        E: std::error::Error + Send + Sync + 'static,    {        let pack_entry = pack.entry(index_entry.pack_offset);        let pack_entry_data_offset = pack_entry.data_offset;        let entry_stats = pack            .decode_entry(                pack_entry,                buf,                |id, _| {                    self.lookup(id)                        .map(|index| crate::data::ResolvedBase::InPack(pack.entry(self.pack_offset_at_index(index))))                },                cache,            )            .map_err(|e| Error::PackDecode {                source: e,                id: index_entry.oid,                offset: index_entry.pack_offset,            })?;        let object_kind = entry_stats.kind;        let header_size = (pack_entry_data_offset - index_entry.pack_offset) as usize;        let entry_len = header_size + entry_stats.compressed_size;         process_entry(            check,            object_kind,            buf,            progress,            header_buf,            index_entry,            || pack.entry_crc32(index_entry.pack_offset, entry_len),            processor,        )?;        Ok(entry_stats)    }} #[allow(clippy::too_many_arguments)]fn process_entry<P, E>(    check: SafetyCheck,    object_kind: git_object::Kind,    decompressed: &[u8],    progress: &mut P,    header_buf: &mut [u8; 64],    index_entry: &crate::index::Entry,    pack_entry_crc32: impl FnOnce() -> u32,    processor: &mut impl FnMut(git_object::Kind, &[u8], &index::Entry, &mut P) -> Result<(), E>,) -> Result<(), Error<E>>where    P: Progress,    E: std::error::Error + Send + Sync + 'static,{    if check.object_checksum() {        let header_size =            crate::loose::object::header::encode(object_kind, decompressed.len() as u64, &mut header_buf[..])                .expect("header buffer to be big enough");        let mut hasher = git_features::hash::Sha1::default();        hasher.update(&header_buf[..header_size]);        hasher.update(decompressed);         let actual_oid = git_hash::ObjectId::new_sha1(hasher.digest());        if actual_oid != index_entry.oid {            return Err(Error::PackObjectMismatch {                actual: actual_oid,                expected: index_entry.oid,                offset: index_entry.pack_offset,                kind: object_kind,            });        }        if let Some(desired_crc32) = index_entry.crc32 {            let actual_crc32 = pack_entry_crc32();            if actual_crc32 != desired_crc32 {                return Err(Error::Crc32Mismatch {                    actual: actual_crc32,                    expected: desired_crc32,                    offset: index_entry.pack_offset,                    kind: object_kind,                });            }        }    }    processor(object_kind, decompressed, index_entry, progress).map_err(Error::Processor)}