gix-pack 0.75.0

use std::{cmp::Ordering, sync::atomic::AtomicBool, time::Instant};

use gix_error::{ErrorExt, ExnResult, retryable};
use gix_features::progress::{Count, DynNestedProgress, Progress};

use crate::{exact_vec, index, multi_index::File};

///
pub mod integrity {

    /// Returned by [`multi_index::File::verify_integrity()`][crate::multi_index::File::verify_integrity()].
    pub struct Outcome {
        /// The computed checksum of the multi-index which matched the stored one.
        pub actual_index_checksum: gix_hash::ObjectId,
        /// The for each entry in [`index_names()`][super::File::index_names()] provide the corresponding pack traversal outcome.
        pub pack_traverse_statistics: Vec<crate::index::traverse::Statistics>,
    }

    /// The progress ids used in [`multi_index::File::verify_integrity()`][crate::multi_index::File::verify_integrity()].
    ///
    /// Use this information to selectively extract the progress of interest in case the parent application has custom visualization.
    #[derive(Debug, Copy, Clone)]
    pub enum ProgressId {
        /// The amount of bytes read to verify the multi-index checksum.
        ChecksumBytes,
        /// The amount of objects whose offset has been checked.
        ObjectOffsets,
    }

    impl From<ProgressId> for gix_features::progress::Id {
        fn from(v: ProgressId) -> Self {
            match v {
                ProgressId::ChecksumBytes => *b"MVCK",
                ProgressId::ObjectOffsets => *b"MVOF",
            }
        }
    }
}

impl<T> File<T>
where
    T: crate::FileData,
{
    /// Validate that our [`checksum()`][File::checksum()] matches the actual contents
    /// of this index file, and return it if it does.
    pub fn verify_checksum(
        &self,
        progress: &mut dyn Progress,
        should_interrupt: &AtomicBool,
    ) -> ExnResult<gix_hash::ObjectId> {
        crate::verify::checksum_on_disk_or_mmap(
            self.path(),
            &self.data,
            self.checksum(),
            self.object_hash,
            progress,
            should_interrupt,
        )
    }

    /// Similar to [`verify_integrity()`][File::verify_integrity()] but without any deep inspection of objects.
    ///
    /// Instead we only validate the contents of the multi-index itself.
    pub fn verify_integrity_fast(
        &self,
        progress: &mut dyn DynNestedProgress,
        should_interrupt: &AtomicBool,
    ) -> ExnResult<gix_hash::ObjectId> {
        self.verify_integrity_inner(
            progress,
            should_interrupt,
            false,
            index::verify::integrity::Options::default(),
        )
        .map(|o| o.actual_index_checksum)
    }

    /// Similar to [`crate::Bundle::verify_integrity()`] but checks all contained indices and their packs.
    ///
    /// Note that it's considered a failure if an index doesn't have a corresponding pack.
    pub fn verify_integrity<C, F>(
        &self,
        progress: &mut dyn DynNestedProgress,
        should_interrupt: &AtomicBool,
        options: index::verify::integrity::Options<F>,
    ) -> ExnResult<integrity::Outcome>
    where
        C: crate::cache::DecodeEntry,
        F: Fn() -> C + Send + Clone,
    {
        self.verify_integrity_inner(progress, should_interrupt, true, options)
    }

    fn verify_integrity_inner<C, F>(
        &self,
        progress: &mut dyn DynNestedProgress,
        should_interrupt: &AtomicBool,
        deep_check: bool,
        options: index::verify::integrity::Options<F>,
    ) -> ExnResult<integrity::Outcome>
    where
        C: crate::cache::DecodeEntry,
        F: Fn() -> C + Send + Clone,
    {
        let parent = self.path.parent().ok_or_else(|| {
            gix_error::validation(format!(
                "The multi-index path '{}' has no parent directory",
                self.path.display()
            ))
            .raise_erased()
        })?;

        let actual_index_checksum = self.verify_checksum(
            &mut progress.add_child_with_id(
                format!("{}: checksum", self.path.display()),
                integrity::ProgressId::ChecksumBytes.into(),
            ),
            should_interrupt,
        )?;

        if let Some(first_invalid) = crate::verify::fan(&self.fan) {
            return Err(gix_error::corruption(format!(
                "The fan at index {first_invalid} is out of order as it's larger then the following value."
            ))
            .raise_erased());
        }

        if self.num_objects == 0 {
            return Err(gix_error::corruption("The multi-index claims to have no objects").raise_erased());
        }

        let mut pack_traverse_statistics = Vec::new();

        let operation_start = Instant::now();
        let mut total_objects_checked = 0;
        let mut pack_ids_and_offsets = exact_vec(self.num_objects as usize);
        {
            let order_start = Instant::now();
            let mut progress = progress.add_child_with_id("checking oid order".into(), gix_features::progress::UNKNOWN);
            progress.init(
                Some(self.num_objects as usize),
                gix_features::progress::count("objects"),
            );

            for entry_index in 0..(self.num_objects - 1) {
                let lhs = self.oid_at_index(entry_index);
                let rhs = self.oid_at_index(entry_index + 1);

                if rhs.cmp(lhs) != Ordering::Greater {
                    return Err(gix_error::corruption(format!(
                        "The object id at multi-index entry {entry_index} wasn't in order"
                    ))
                    .raise_erased());
                }
                let (pack_id, _) = self.pack_id_and_pack_offset_at_index(entry_index);
                pack_ids_and_offsets.push((pack_id, entry_index));
                progress.inc();
            }
            {
                let entry_index = self.num_objects - 1;
                let (pack_id, _) = self.pack_id_and_pack_offset_at_index(entry_index);
                pack_ids_and_offsets.push((pack_id, entry_index));
            }
            // sort by pack-id to allow handling all indices matching a pack while its open.
            pack_ids_and_offsets.sort_by_key(|l| l.0);
            progress.show_throughput(order_start);
        };

        progress.init(
            Some(self.num_indices as usize),
            gix_features::progress::count("indices"),
        );

        let mut pack_ids_slice = pack_ids_and_offsets.as_slice();

        for (pack_id, index_file_name) in self.index_names.iter().enumerate() {
            progress.set_name(index_file_name.display().to_string());
            progress.inc();

            let mut bundle = None;
            let index;
            let index_path = parent.join(index_file_name);
            let index = if deep_check {
                let mut opened_bundle = crate::Bundle::at(index_path, self.object_hash)?;
                opened_bundle.pack.alloc_limit_bytes = self.alloc_limit_bytes;
                bundle = Some(opened_bundle);
                bundle.as_ref().map(|b| &b.index).expect("just set")
            } else {
                index = Some(index::File::at(index_path, self.object_hash)?);
                index.as_ref().expect("just set")
            };

            let slice_end = pack_ids_slice.partition_point(|e| e.0 == pack_id as crate::data::Id);
            let multi_index_entries_to_check = &pack_ids_slice[..slice_end];
            {
                let offset_start = Instant::now();
                let mut offsets_progress = progress.add_child_with_id(
                    "verify object offsets".into(),
                    integrity::ProgressId::ObjectOffsets.into(),
                );
                offsets_progress.init(
                    Some(pack_ids_and_offsets.len()),
                    gix_features::progress::count("objects"),
                );
                pack_ids_slice = &pack_ids_slice[slice_end..];

                for entry_id in multi_index_entries_to_check.iter().map(|e| e.1) {
                    let oid = self.oid_at_index(entry_id);
                    let (_, expected_pack_offset) = self.pack_id_and_pack_offset_at_index(entry_id);
                    let entry_in_bundle_index = index.lookup(oid).ok_or_else(|| {
                        gix_error::corruption(format!(
                            "{oid} wasn't found in the index referenced in the multi-pack index"
                        ))
                        .raise_erased()
                    })?;
                    let actual_pack_offset = index.pack_offset_at_index(entry_in_bundle_index);
                    if actual_pack_offset != expected_pack_offset {
                        return Err(gix_error::corruption(format!(
                            "Object {oid} should be at pack-offset {expected_pack_offset} but was found at {actual_pack_offset}"
                        ))
                        .raise_erased());
                    }
                    offsets_progress.inc();
                }

                if should_interrupt.load(std::sync::atomic::Ordering::Relaxed) {
                    return Err(retryable("Interrupted").raise_erased());
                }
                offsets_progress.show_throughput(offset_start);
            }

            total_objects_checked += multi_index_entries_to_check.len();

            if let Some(bundle) = bundle {
                progress.set_name(format!("Validating {}", index_file_name.display()));
                let crate::bundle::verify::integrity::Outcome {
                    actual_index_checksum: _,
                    pack_traverse_outcome,
                } = bundle.verify_integrity(progress, should_interrupt, options.clone())?;
                pack_traverse_statistics.push(pack_traverse_outcome);
            }
        }

        assert_eq!(
            self.num_objects as usize, total_objects_checked,
            "BUG: our slicing should allow to visit all objects"
        );

        progress.set_name("Validating multi-pack".into());
        progress.show_throughput(operation_start);

        Ok(integrity::Outcome {
            actual_index_checksum,
            pack_traverse_statistics,
        })
    }
}