use super::DecodeEntry; #[cfg(feature = "pack-cache-lru-dynamic")]mod memory {    use std::num::NonZeroUsize;     use clru::WeightScale;     use super::DecodeEntry;     struct Entry {        data: Vec<u8>,        kind: git_object::Kind,        compressed_size: usize,    }     type Key = (u32, u64);    struct CustomScale;     impl WeightScale<Key, Entry> for CustomScale {        fn weight(&self, _key: &Key, value: &Entry) -> usize {            value.data.len()        }    }     /// An LRU cache with hash map backing and an eviction rule based on the memory usage for object data in bytes.    pub struct MemoryCappedHashmap {        inner: clru::CLruCache<Key, Entry, std::collections::hash_map::RandomState, CustomScale>,        free_list: Vec<Vec<u8>>,        debug: git_features::cache::Debug,    }     impl MemoryCappedHashmap {        /// Return a new instance which evicts least recently used items if it uses more than `memory_cap_in_bytes`        /// object data.        pub fn new(memory_cap_in_bytes: usize) -> MemoryCappedHashmap {            MemoryCappedHashmap {                inner: clru::CLruCache::with_config(                    clru::CLruCacheConfig::new(NonZeroUsize::new(memory_cap_in_bytes).expect("non zero"))                        .with_scale(CustomScale),                ),                free_list: Vec::new(),                debug: git_features::cache::Debug::new(format!("MemoryCappedHashmap({}B)", memory_cap_in_bytes)),            }        }    }     impl DecodeEntry for MemoryCappedHashmap {        fn put(&mut self, pack_id: u32, offset: u64, data: &[u8], kind: git_object::Kind, compressed_size: usize) {            self.debug.put();            if let Ok(Some(previous_entry)) = self.inner.put_with_weight(                (pack_id, offset),                Entry {                    data: self                        .free_list                        .pop()                        .map(|mut v| {                            v.clear();                            v.resize(data.len(), 0);                            v.copy_from_slice(data);                            v                        })                        .unwrap_or_else(|| Vec::from(data)),                    kind,                    compressed_size,                },            ) {                self.free_list.push(previous_entry.data)            }        }         fn get(&mut self, pack_id: u32, offset: u64, out: &mut Vec<u8>) -> Option<(git_object::Kind, usize)> {            let res = self.inner.get(&(pack_id, offset)).map(|e| {                out.resize(e.data.len(), 0);                out.copy_from_slice(&e.data);                (e.kind, e.compressed_size)            });            if res.is_some() {                self.debug.hit()            } else {                self.debug.miss()            }            res        }    }} #[cfg(feature = "pack-cache-lru-dynamic")]pub use memory::MemoryCappedHashmap; #[cfg(feature = "pack-cache-lru-static")]mod _static {    use super::DecodeEntry;    struct Entry {        pack_id: u32,        offset: u64,        data: Vec<u8>,        kind: git_object::Kind,        compressed_size: usize,    }     /// A cache using a least-recently-used implementation capable of storing the `SIZE` most recent objects.    /// The cache must be small as the search is 'naive' and the underlying data structure is a linked list.    /// Values of 64 seem to improve performance.    pub struct StaticLinkedList<const SIZE: usize> {        inner: uluru::LRUCache<Entry, SIZE>,        free_list: Vec<Vec<u8>>,        debug: git_features::cache::Debug,    }     impl<const SIZE: usize> Default for StaticLinkedList<SIZE> {        fn default() -> Self {            StaticLinkedList {                inner: Default::default(),                free_list: Vec::new(),                debug: git_features::cache::Debug::new(format!("StaticLinkedList<{}>", SIZE)),            }        }    }     impl<const SIZE: usize> DecodeEntry for StaticLinkedList<SIZE> {        fn put(&mut self, pack_id: u32, offset: u64, data: &[u8], kind: git_object::Kind, compressed_size: usize) {            self.debug.put();            if let Some(previous) = self.inner.insert(Entry {                offset,                pack_id,                data: self                    .free_list                    .pop()                    .map(|mut v| {                        v.clear();                        v.resize(data.len(), 0);                        v.copy_from_slice(data);                        v                    })                    .unwrap_or_else(|| Vec::from(data)),                kind,                compressed_size,            }) {                self.free_list.push(previous.data)            }        }         fn get(&mut self, pack_id: u32, offset: u64, out: &mut Vec<u8>) -> Option<(git_object::Kind, usize)> {            let res = self.inner.lookup(|e: &mut Entry| {                if e.pack_id == pack_id && e.offset == offset {                    out.resize(e.data.len(), 0);                    out.copy_from_slice(&e.data);                    Some((e.kind, e.compressed_size))                } else {                    None                }            });            if res.is_some() {                self.debug.hit()            } else {                self.debug.miss()            }            res        }    }} #[cfg(feature = "pack-cache-lru-static")]pub use _static::StaticLinkedList;