pub trait Find {
type Error: Error + Send + Sync + 'static;
// Required methods
fn contains(&self, id: impl AsRef<oid>) -> bool;
fn try_find_cached<'a>(
&self,
id: impl AsRef<oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl DecodeEntry
) -> Result<Option<(Data<'a>, Option<Location>)>, Self::Error>;
fn location_by_oid(
&self,
id: impl AsRef<oid>,
buf: &mut Vec<u8>
) -> Option<Location>;
fn pack_offsets_and_oid(
&self,
pack_id: u32
) -> Option<Vec<(Offset, ObjectId)>>;
fn entry_by_location(&self, location: &Location) -> Option<Entry>;
// Provided method
fn try_find<'a>(
&self,
id: impl AsRef<oid>,
buffer: &'a mut Vec<u8>
) -> Result<Option<(Data<'a>, Option<Location>)>, Self::Error> { ... }
}Expand description
Describe how object can be located in an object store with built-in facilities to supports packs specifically.
Notes
Find effectively needs generic associated types to allow a trait for the returned object type. Until then, we will have to make due with explicit types and give them the potentially added features we want.
Furthermore, despite this trait being in git-pack, it leaks knowledge about objects potentially not being packed.
This is a necessary trade-off to allow this trait to live in git-pack where it is used in functions to create a pack.
Required Associated Types§
Required Methods§
sourcefn contains(&self, id: impl AsRef<oid>) -> bool
fn contains(&self, id: impl AsRef<oid>) -> bool
Returns true if the object exists in the database.
sourcefn try_find_cached<'a>(
&self,
id: impl AsRef<oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl DecodeEntry
) -> Result<Option<(Data<'a>, Option<Location>)>, Self::Error>
fn try_find_cached<'a>( &self, id: impl AsRef<oid>, buffer: &'a mut Vec<u8>, pack_cache: &mut impl DecodeEntry ) -> Result<Option<(Data<'a>, Option<Location>)>, Self::Error>
Like Find::try_find(), but with support for controlling the pack cache.
A pack_cache can be used to speed up subsequent lookups, set it to crate::cache::Never if the
workload isn’t suitable for caching.
Returns Some((<object data>, <pack location if packed>)) if it was present in the database,
or the error that occurred during lookup or object retrieval.
sourcefn location_by_oid(
&self,
id: impl AsRef<oid>,
buf: &mut Vec<u8>
) -> Option<Location>
fn location_by_oid( &self, id: impl AsRef<oid>, buf: &mut Vec<u8> ) -> Option<Location>
Find the packs location where an object with id can be found in the database, or None if there is no pack
holding the object.
Note that this is always None if the object isn’t packed even though it exists as loose object.
sourcefn pack_offsets_and_oid(&self, pack_id: u32) -> Option<Vec<(Offset, ObjectId)>>
fn pack_offsets_and_oid(&self, pack_id: u32) -> Option<Vec<(Offset, ObjectId)>>
Obtain a vector of all offsets, in index order, along with their object id.
sourcefn entry_by_location(&self, location: &Location) -> Option<Entry>
fn entry_by_location(&self, location: &Location) -> Option<Entry>
Return the find::Entry for location if it is backed by a pack.
Note that this is only in the interest of avoiding duplicate work during pack generation.
Pack locations can be obtained from Find::try_find().
Notes
Custom implementations might be interested in providing their own meta-data with object,
which currently isn’t possible as the Locate trait requires GATs to work like that.
Provided Methods§
sourcefn try_find<'a>(
&self,
id: impl AsRef<oid>,
buffer: &'a mut Vec<u8>
) -> Result<Option<(Data<'a>, Option<Location>)>, Self::Error>
fn try_find<'a>( &self, id: impl AsRef<oid>, buffer: &'a mut Vec<u8> ) -> Result<Option<(Data<'a>, Option<Location>)>, Self::Error>
Find an object matching id in the database while placing its raw, decoded data into buffer.
A pack_cache can be used to speed up subsequent lookups, set it to crate::cache::Never if the
workload isn’t suitable for caching.
Returns Some((<object data>, <pack location if packed>)) if it was present in the database,
or the error that occurred during lookup or object retrieval.