mod file {    use git_hash::SIZE_OF_SHA1_DIGEST as SHA1_SIZE;    use git_object::{self as object};    use git_odb::pack;     use crate::{        fixture_path, hex_to_id,        pack::{INDEX_V1, PACK_FOR_INDEX_V1, SMALL_PACK, SMALL_PACK_INDEX},    };     mod method {        mod v1 {            use git_pack::index;             use crate::{fixture_path, pack::INDEX_V1};             #[test]            fn lookup() -> Result<(), Box<dyn std::error::Error>> {                let idx = index::File::at(&fixture_path(INDEX_V1))?;                for (id, desired_index, assertion) in &[                    (&b"036bd66fe9b6591e959e6df51160e636ab1a682e"[..], Some(0), "first"),                    (b"f7f791d96b9a34ef0f08db4b007c5309b9adc3d6", Some(65), "close to last"),                    (b"ffffffffffffffffffffffffffffffffffffffff", None, "not in pack"),                ] {                    assert_eq!(                        idx.lookup(git_hash::ObjectId::from_hex(*id)?),                        *desired_index,                        "{}",                        assertion                    );                }                for entry in idx.iter() {                    let index = idx.lookup(entry.oid).expect("id present");                    assert_eq!(entry.oid.as_ref(), idx.oid_at_index(index));                    assert_eq!(entry.pack_offset, idx.pack_offset_at_index(index));                    assert_eq!(entry.crc32, idx.crc32_at_index(index));                }                Ok(())            }        }         mod v2 {            use git_pack::index;             use crate::{fixture_path, pack::INDEX_V2};             #[test]            fn lookup() -> Result<(), Box<dyn std::error::Error>> {                let idx = index::File::at(&fixture_path(INDEX_V2))?;                for (id, desired_index, assertion) in &[                    (&b"0ead45fc727edcf5cadca25ef922284f32bb6fc1"[..], Some(0), "first"),                    (b"e800b9c207e17f9b11e321cc1fba5dfe08af4222", Some(29), "last"),                    (b"ffffffffffffffffffffffffffffffffffffffff", None, "not in pack"),                ] {                    assert_eq!(                        idx.lookup(git_hash::ObjectId::from_hex(*id)?),                        *desired_index,                        "{}",                        assertion                    );                }                for entry in idx.iter() {                    let index = idx.lookup(entry.oid).expect("id present");                    assert_eq!(entry.oid.as_ref(), idx.oid_at_index(index));                    assert_eq!(entry.pack_offset, idx.pack_offset_at_index(index));                    assert_eq!(entry.crc32, idx.crc32_at_index(index), "{} {:?}", index, entry);                }                Ok(())            }        }         mod any {            use std::{fs, io, sync::atomic::AtomicBool};             use filebuffer::FileBuffer;            use git_features::progress;            use git_odb::pack;            use git_pack::data::{input, EntryRange};             use crate::{fixture_path, pack::V2_PACKS_AND_INDICES};             #[test]            fn write_to_stream() -> Result<(), Box<dyn std::error::Error>> {                for mode in &[input::Mode::AsIs, input::Mode::Verify, input::Mode::Restore] {                    for compressed in &[input::EntryDataMode::Crc32, input::EntryDataMode::KeepAndCrc32] {                        for (index_path, data_path) in V2_PACKS_AND_INDICES {                            let resolve = {                                let buf = FileBuffer::open(fixture_path(data_path))?;                                move |entry: EntryRange, out: &mut Vec<u8>| {                                    buf.get(entry.start as usize..entry.end as usize)                                        .map(|slice| out.copy_from_slice(slice))                                }                            };                            assert_index_write(mode, compressed, index_path, data_path, resolve)?;                        }                    }                }                Ok(())            }             fn assert_index_write<F>(                mode: &input::Mode,                compressed: &input::EntryDataMode,                index_path: &&str,                data_path: &&str,                resolve: F,            ) -> Result<(), Box<dyn std::error::Error>>            where                F: Fn(pack::data::EntryRange, &mut Vec<u8>) -> Option<()> + Send + Sync,            {                let pack_iter = pack::data::input::BytesToEntriesIter::new_from_header(                    io::BufReader::new(fs::File::open(fixture_path(data_path))?),                    *mode,                    *compressed,                )?;                 let mut actual = Vec::<u8>::new();                let desired_kind = pack::index::Version::default();                let num_objects = pack_iter.len() as u32;                let outcome = pack::index::File::write_data_iter_to_stream(                    desired_kind,                    || Ok(resolve),                    pack_iter,                    None,                    progress::Discard,                    &mut actual,                    &AtomicBool::new(false),                )?;                 let expected = fs::read(fixture_path(index_path))?;                let end_of_header = 4 * 2;                assert_eq!(&actual[..end_of_header], &expected[..end_of_header], "header");                let end_of_fanout_table = end_of_header + 256 * 4;                assert_eq!(                    &actual[end_of_header..end_of_fanout_table],                    &expected[end_of_header..end_of_fanout_table],                    "fan out table"                );                let end_of_ids = end_of_fanout_table + 20 * num_objects as usize;                assert_eq!(                    &actual[end_of_fanout_table..end_of_ids],                    &expected[end_of_fanout_table..end_of_ids],                    "hashes: sha1"                );                let end_of_crc32 = end_of_ids + 4 * num_objects as usize;                assert_eq!(                    &actual[end_of_ids..end_of_crc32],                    &expected[end_of_ids..end_of_crc32],                    "crc32"                );                let end_of_offsets = end_of_crc32 + 4 * num_objects as usize;                assert_eq!(                    &actual[end_of_crc32..end_of_offsets],                    &expected[end_of_crc32..end_of_offsets],                    "offsets"                );                let end_of_pack_hash = end_of_offsets + 20;                assert_eq!(                    &actual[end_of_offsets..end_of_pack_hash],                    &expected[end_of_offsets..end_of_pack_hash],                    "offsets"                );                let end_of_index_hash = end_of_pack_hash + 20;                assert_eq!(                    &actual[end_of_pack_hash..end_of_index_hash],                    &expected[end_of_pack_hash..end_of_index_hash],                    "index hash"                );                assert_eq!(                    actual, expected,                    "we should be writing a bit-exact version of the original V2 index"                );                assert_eq!(                    outcome.num_objects, num_objects,                    "it wrote the entire iterator worth of entries"                );                assert_eq!(outcome.index_kind, desired_kind);                assert_eq!(                    outcome.index_hash,                    git_hash::ObjectId::from_20_bytes(&expected[end_of_pack_hash..end_of_index_hash])                );                Ok(())            }        }    }     use common_macros::b_tree_map;    use git_features::progress;    use git_pack::{cache, data::decode_entry::Outcome, index};     use crate::pack::{INDEX_V2, PACK_FOR_INDEX_V2};     static ALGORITHMS: &[index::traverse::Algorithm] = &[        index::traverse::Algorithm::Lookup,        index::traverse::Algorithm::DeltaTreeLookup,    ];     static MODES: &[index::verify::Mode] = &[        index::verify::Mode::Sha1Crc32,        index::verify::Mode::Sha1Crc32Decode,        index::verify::Mode::Sha1Crc32DecodeEncode,    ];     #[test]    fn pack_lookup() -> Result<(), Box<dyn std::error::Error>> {        for (index_path, pack_path, stats) in &[            (                INDEX_V2,                PACK_FOR_INDEX_V2,                index::traverse::Outcome {                    average: Outcome {                        kind: object::Kind::Tree,                        num_deltas: 1,                        decompressed_size: 3456,                        compressed_size: 1725,                        object_size: 9621,                    },                    objects_per_chain_length: b_tree_map! {                        0 => 18,                        1 => 4,                        2 => 3,                        3 => 1,                        4 => 2,                        5 => 1,                        6 => 1,                    },                    total_compressed_entries_size: 51753,                    total_decompressed_entries_size: 103701,                    total_object_size: 288658,                    num_commits: 10,                    num_blobs: 5,                    num_tags: 0,                    num_trees: 15,                    pack_size: 51875,                },            ),            (                INDEX_V1,                PACK_FOR_INDEX_V1,                index::traverse::Outcome {                    average: Outcome {                        kind: object::Kind::Tree,                        num_deltas: 0,                        decompressed_size: 1982,                        compressed_size: 729,                        object_size: 2093,                    },                    objects_per_chain_length: b_tree_map! {                        0 => 64,                        1 => 3                    },                    total_compressed_entries_size: 48867,                    total_decompressed_entries_size: 132823,                    total_object_size: 140243,                    num_commits: 2,                    num_blobs: 63,                    num_tags: 0,                    num_trees: 2,                    pack_size: 49113,                },            ),            (                SMALL_PACK_INDEX,                SMALL_PACK,                index::traverse::Outcome {                    average: Outcome {                        kind: object::Kind::Tree,                        num_deltas: 0,                        decompressed_size: 118,                        compressed_size: 85,                        object_size: 293,                    },                    objects_per_chain_length: b_tree_map! {                        0 => 30,                        1 => 6,                        2 => 6,                    },                    total_compressed_entries_size: 3604,                    total_decompressed_entries_size: 4997,                    total_object_size: 12307,                    num_commits: 14,                    num_blobs: 14,                    num_tags: 0,                    num_trees: 14,                    pack_size: 3732,                },            ),        ] {            let idx = index::File::at(&fixture_path(index_path))?;            let pack = pack::data::File::at(&fixture_path(pack_path))?;             assert_eq!(pack.version(), pack::data::Version::V2);            assert_eq!(pack.num_objects(), idx.num_objects());            for algo in ALGORITHMS {                for mode in MODES {                    assert_eq!(                        idx.verify_integrity(                            Some((&pack, *mode, *algo, || cache::Never)),                            None,                            progress::Discard.into(),                            Default::default()                        )                        .map(|(a, b, _)| (a, b))?,                        (idx.index_checksum(), Some(stats.to_owned())),                        "{:?} -> {:?}",                        algo,                        mode                    );                }            }            let num_objects = stats                .objects_per_chain_length                .values()                .map(|v| *v as usize)                .sum::<usize>();            let sorted_offsets = idx.sorted_offsets();            assert_eq!(num_objects, sorted_offsets.len());            for idx_entry in idx.iter() {                let pack_entry = pack.entry(idx_entry.pack_offset);                assert_ne!(pack_entry.data_offset, idx_entry.pack_offset);                assert!(sorted_offsets.binary_search(&idx_entry.pack_offset).is_ok());            }            for (entry, offset_from_index) in pack.streaming_iter()?.zip(sorted_offsets.iter().copied()) {                let entry = entry?;                assert_eq!(                    entry.pack_offset, offset_from_index,                    "iteration should yield the same pack offsets as the index"                );                 let mut buf = Vec::new();                buf.resize(entry.decompressed_size as usize, 0);                let pack_entry = pack.entry(offset_from_index);                assert_eq!(                    pack_entry.pack_offset(),                    entry.pack_offset,                    "index entry offset and computed pack offset must match"                );                pack.decompress_entry(&pack_entry, &mut buf)?;                 assert_eq!(                    buf.len() as u64,                    entry.decompressed_size,                    "the decompressed length are the same no matter what decompressed them"                );                 let next_offset_index = sorted_offsets                    .binary_search(&entry.pack_offset)                    .expect("correct offset")                    + 1;                let next_offset = if next_offset_index == sorted_offsets.len() {                    (pack.data_len() - SHA1_SIZE) as u64                } else {                    sorted_offsets[next_offset_index]                };                assert_eq!(                    entry                        .compressed                        .expect("bytes present in default configuration of streaming iter")                        .len() as u64,                    next_offset - entry.pack_offset - entry.header_size as u64,                    "we get the compressed bytes region after the head to the next entry"                );            }        }        Ok(())    }     #[test]    fn iter() -> Result<(), Box<dyn std::error::Error>> {        for (path, kind, num_objects, index_checksum, pack_checksum) in &[            (                INDEX_V1,                index::Version::V1,                67,                "5a2b20ef73ffe911178532df86232b64830cb536",                "7ebaef998897d903e6e6b6763d3a6ec4dc5b845b",            ),            (                INDEX_V2,                index::Version::V2,                30,                "560eba66e6b391eb83efc3ec9fc8a3087788911c",                "f1cd3cc7bc63a4a2b357a475a58ad49b40355470",            ),            (                SMALL_PACK_INDEX,                index::Version::V2,                42,                "544a7204a55f6e9cacccf8f6e191ea8f83575de3",                "0f3ea84cd1bba10c2a03d736a460635082833e59",            ),        ] {            let idx = index::File::at(&fixture_path(path))?;            assert_eq!(idx.version(), *kind);            assert_eq!(idx.num_objects(), *num_objects);            assert_eq!(                idx.verify_integrity(                    None::<(_, _, _, fn() -> cache::Never)>,                    None,                    progress::Discard.into(),                    Default::default()                )                .map(|(a, b, _)| (a, b))?,                (idx.index_checksum(), None)            );            assert_eq!(idx.index_checksum(), hex_to_id(index_checksum));            assert_eq!(idx.pack_checksum(), hex_to_id(pack_checksum));            assert_eq!(idx.iter().count(), *num_objects as usize);        }        Ok(())    }}