1 files changed, 234 insertions, 0 deletions
diff --git a/vendor/gix-odb/src/cache.rs b/vendor/gix-odb/src/cache.rs
new file mode 100644
index 000000000..8e108646f
--- /dev/null
+++ b/vendor/gix-odb/src/cache.rs
@@ -0,0 +1,234 @@
+use std::{
+    cell::RefCell,
+    ops::{Deref, DerefMut},
+    rc::Rc,
+    sync::Arc,
+};
+
+use crate::Cache;
+
+/// A type to store pack caches in boxes.
+pub type PackCache = dyn gix_pack::cache::DecodeEntry + Send + 'static;
+/// A constructor for boxed pack caches.
+pub type NewPackCacheFn = dyn Fn() -> Box<PackCache> + Send + Sync + 'static;
+
+/// A type to store object caches in boxes.
+pub type ObjectCache = dyn gix_pack::cache::Object + Send + 'static;
+/// A constructor for boxed object caches.
+pub type NewObjectCacheFn = dyn Fn() -> Box<ObjectCache> + Send + Sync + 'static;
+
+impl Cache<crate::store::Handle<Rc<crate::Store>>> {
+    /// Convert this cache's handle into one that keeps its store in an arc. This creates an entirely new store,
+    /// so should be done early to avoid unnecessary work (and mappings).
+    pub fn into_arc(self) -> std::io::Result<Cache<crate::store::Handle<Arc<crate::Store>>>> {
+        let inner = self.inner.into_arc()?;
+        Ok(Cache {
+            inner,
+            new_pack_cache: self.new_pack_cache,
+            new_object_cache: self.new_object_cache,
+            pack_cache: self.pack_cache,
+            object_cache: self.object_cache,
+        })
+    }
+}
+impl Cache<crate::store::Handle<Arc<crate::Store>>> {
+    /// No op, as we are containing an arc handle already.
+    pub fn into_arc(self) -> std::io::Result<Cache<crate::store::Handle<Arc<crate::Store>>>> {
+        Ok(self)
+    }
+}
+
+impl<S> Cache<S> {
+    /// Dissolve this instance, discard all caches, and return the inner implementation.
+    pub fn into_inner(self) -> S {
+        self.inner
+    }
+    /// Use this methods directly after creating a new instance to add a constructor for pack caches.
+    ///
+    /// These are used to speed up decoding objects which are located in packs, reducing long delta chains by storing
+    /// their intermediate results.
+    pub fn with_pack_cache(mut self, create: impl Fn() -> Box<PackCache> + Send + Sync + 'static) -> Self {
+        self.pack_cache = Some(RefCell::new(create()));
+        self.new_pack_cache = Some(Arc::new(create));
+        self
+    }
+    /// Use this methods directly after creating a new instance to add a constructor for object caches.
+    ///
+    /// Only use this kind of cache if the same objects are repeatedly accessed for great speedups, usually during diffing of
+    /// trees.
+    pub fn with_object_cache(mut self, create: impl Fn() -> Box<ObjectCache> + Send + Sync + 'static) -> Self {
+        self.object_cache = Some(RefCell::new(create()));
+        self.new_object_cache = Some(Arc::new(create));
+        self
+    }
+    /// Set the pack cache constructor on this instance.
+    pub fn set_pack_cache(&mut self, create: impl Fn() -> Box<PackCache> + Send + Sync + 'static) {
+        self.pack_cache = Some(RefCell::new(create()));
+        self.new_pack_cache = Some(Arc::new(create));
+    }
+    /// Set the object cache constructor on this instance.
+    pub fn set_object_cache(&mut self, create: impl Fn() -> Box<ObjectCache> + Send + Sync + 'static) {
+        self.object_cache = Some(RefCell::new(create()));
+        self.new_object_cache = Some(Arc::new(create));
+    }
+    /// Return true if an object cache is present.
+    pub fn has_object_cache(&self) -> bool {
+        self.object_cache.is_some()
+    }
+    /// Return true if a pack cache is present.
+    pub fn has_pack_cache(&self) -> bool {
+        self.pack_cache.is_some()
+    }
+    /// Remove the current pack cache as well as its constructor from this instance.
+    pub fn unset_pack_cache(&mut self) {
+        self.pack_cache = None;
+        self.new_pack_cache = None;
+    }
+    /// Remove the current object cache as well as its constructor from this instance.
+    pub fn unset_object_cache(&mut self) {
+        self.object_cache = None;
+        self.new_object_cache = None;
+    }
+}
+
+impl<S> From<S> for Cache<S>
+where
+    S: gix_pack::Find,
+{
+    fn from(store: S) -> Self {
+        Self {
+            inner: store,
+            pack_cache: None,
+            new_pack_cache: None,
+            object_cache: None,
+            new_object_cache: None,
+        }
+    }
+}
+
+impl<S: Clone> Clone for Cache<S> {
+    fn clone(&self) -> Self {
+        Cache {
+            inner: self.inner.clone(),
+            new_pack_cache: self.new_pack_cache.clone(),
+            new_object_cache: self.new_object_cache.clone(),
+            pack_cache: self.new_pack_cache.as_ref().map(|create| RefCell::new(create())),
+            object_cache: self.new_object_cache.as_ref().map(|create| RefCell::new(create())),
+        }
+    }
+}
+
+impl<S> Deref for Cache<S> {
+    type Target = S;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl<S> DerefMut for Cache<S> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.inner
+    }
+}
+
+mod impls {
+    use std::{io::Read, ops::DerefMut};
+
+    use gix_hash::{oid, ObjectId};
+    use gix_object::{Data, Kind};
+    use gix_pack::cache::Object;
+
+    use crate::{find::Header, pack::data::entry::Location, Cache};
+
+    impl<S> crate::Write for Cache<S>
+    where
+        S: crate::Write,
+    {
+        type Error = S::Error;
+
+        fn write_stream(&self, kind: Kind, size: u64, from: impl Read) -> Result<ObjectId, Self::Error> {
+            self.inner.write_stream(kind, size, from)
+        }
+    }
+
+    impl<S> crate::Find for Cache<S>
+    where
+        S: gix_pack::Find,
+    {
+        type Error = S::Error;
+
+        fn contains(&self, id: impl AsRef<oid>) -> bool {
+            self.inner.contains(id)
+        }
+
+        fn try_find<'a>(&self, id: impl AsRef<oid>, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, Self::Error> {
+            gix_pack::Find::try_find(self, id, buffer).map(|t| t.map(|t| t.0))
+        }
+    }
+
+    impl<S> crate::Header for Cache<S>
+    where
+        S: crate::Header,
+    {
+        type Error = S::Error;
+
+        fn try_header(&self, id: impl AsRef<oid>) -> Result<Option<Header>, Self::Error> {
+            self.inner.try_header(id)
+        }
+    }
+
+    impl<S> gix_pack::Find for Cache<S>
+    where
+        S: gix_pack::Find,
+    {
+        type Error = S::Error;
+
+        fn contains(&self, id: impl AsRef<oid>) -> bool {
+            self.inner.contains(id)
+        }
+
+        fn try_find<'a>(
+            &self,
+            id: impl AsRef<oid>,
+            buffer: &'a mut Vec<u8>,
+        ) -> Result<Option<(Data<'a>, Option<Location>)>, Self::Error> {
+            match self.pack_cache.as_ref().map(|rc| rc.borrow_mut()) {
+                Some(mut pack_cache) => self.try_find_cached(id, buffer, pack_cache.deref_mut()),
+                None => self.try_find_cached(id, buffer, &mut gix_pack::cache::Never),
+            }
+        }
+
+        fn try_find_cached<'a>(
+            &self,
+            id: impl AsRef<oid>,
+            buffer: &'a mut Vec<u8>,
+            pack_cache: &mut impl gix_pack::cache::DecodeEntry,
+        ) -> Result<Option<(Data<'a>, Option<gix_pack::data::entry::Location>)>, Self::Error> {
+            if let Some(mut obj_cache) = self.object_cache.as_ref().map(|rc| rc.borrow_mut()) {
+                if let Some(kind) = obj_cache.get(&id.as_ref().to_owned(), buffer) {
+                    return Ok(Some((Data::new(kind, buffer), None)));
+                }
+            }
+            let possibly_obj = self.inner.try_find_cached(id.as_ref(), buffer, pack_cache)?;
+            if let (Some(mut obj_cache), Some((obj, _location))) =
+                (self.object_cache.as_ref().map(|rc| rc.borrow_mut()), &possibly_obj)
+            {
+                obj_cache.put(id.as_ref().to_owned(), obj.kind, obj.data);
+            }
+            Ok(possibly_obj)
+        }
+
+        fn location_by_oid(&self, id: impl AsRef<oid>, buf: &mut Vec<u8>) -> Option<gix_pack::data::entry::Location> {
+            self.inner.location_by_oid(id, buf)
+        }
+
+        fn pack_offsets_and_oid(&self, pack_id: u32) -> Option<Vec<(u64, gix_hash::ObjectId)>> {
+            self.inner.pack_offsets_and_oid(pack_id)
+        }
+
+        fn entry_by_location(&self, location: &Location) -> Option<gix_pack::find::Entry> {
+            self.inner.entry_by_location(location)
+        }
+    }
+}