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Diffstat (limited to 'vendor/gix-odb/src/traits.rs')
-rw-r--r-- | vendor/gix-odb/src/traits.rs | 310 |
1 files changed, 310 insertions, 0 deletions
diff --git a/vendor/gix-odb/src/traits.rs b/vendor/gix-odb/src/traits.rs new file mode 100644 index 000000000..ddec78b8e --- /dev/null +++ b/vendor/gix-odb/src/traits.rs @@ -0,0 +1,310 @@ +use std::io; + +use gix_object::WriteTo; + +/// Describe the capability to write git objects into an object store. +pub trait Write { + /// The error type used for all trait methods. + /// + /// _Note_ the default implementations require the `From<io::Error>` bound. + type Error: std::error::Error + From<io::Error>; + + /// Write objects using the intrinsic kind of [`hash`][gix_hash::Kind] into the database, + /// returning id to reference it in subsequent reads. + fn write(&self, object: impl WriteTo) -> Result<gix_hash::ObjectId, Self::Error> { + let mut buf = Vec::with_capacity(2048); + object.write_to(&mut buf)?; + self.write_stream(object.kind(), buf.len() as u64, buf.as_slice()) + } + /// As [`write`][Write::write], but takes an [`object` kind][gix_object::Kind] along with its encoded bytes. + fn write_buf(&self, object: gix_object::Kind, from: &[u8]) -> Result<gix_hash::ObjectId, Self::Error> { + self.write_stream(object, from.len() as u64, from) + } + /// As [`write`][Write::write], but takes an input stream. + /// This is commonly used for writing blobs directly without reading them to memory first. + fn write_stream( + &self, + kind: gix_object::Kind, + size: u64, + from: impl io::Read, + ) -> Result<gix_hash::ObjectId, Self::Error>; +} + +/// Describe how object can be located in an object store. +/// +/// ## Notes +/// +/// Find effectively needs [generic associated types][issue] 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. +/// +/// [issue]: https://github.com/rust-lang/rust/issues/44265 +pub trait Find { + /// The error returned by [`try_find()`][Find::try_find()] + type Error: std::error::Error + 'static; + + /// Returns true if the object exists in the database. + fn contains(&self, id: impl AsRef<gix_hash::oid>) -> bool; + + /// Find an object matching `id` in the database while placing its raw, possibly encoded data into `buffer`. + /// + /// Returns `Some` object if it was present in the database, or the error that occurred during lookup or object + /// retrieval. + fn try_find<'a>( + &self, + id: impl AsRef<gix_hash::oid>, + buffer: &'a mut Vec<u8>, + ) -> Result<Option<gix_object::Data<'a>>, Self::Error>; +} + +/// A way to obtain object properties without fully decoding it. +pub trait Header { + /// The error returned by [`try_header()`][Header::try_header()]. + type Error: std::error::Error + 'static; + /// Try to read the header of the object associated with `id` or return `None` if it could not be found. + fn try_header(&self, id: impl AsRef<gix_hash::oid>) -> Result<Option<find::Header>, Self::Error>; +} + +mod _impls { + use std::{io::Read, ops::Deref, rc::Rc, sync::Arc}; + + use gix_hash::{oid, ObjectId}; + use gix_object::{Data, Kind, WriteTo}; + + use crate::find::Header; + + impl<T> crate::Write for &T + where + T: crate::Write, + { + type Error = T::Error; + + fn write(&self, object: impl WriteTo) -> Result<ObjectId, Self::Error> { + (*self).write(object) + } + + fn write_buf(&self, object: Kind, from: &[u8]) -> Result<ObjectId, Self::Error> { + (*self).write_buf(object, from) + } + + fn write_stream(&self, kind: Kind, size: u64, from: impl Read) -> Result<ObjectId, Self::Error> { + (*self).write_stream(kind, size, from) + } + } + + impl<T> crate::Write for Arc<T> + where + T: crate::Write, + { + type Error = T::Error; + + fn write(&self, object: impl WriteTo) -> Result<ObjectId, Self::Error> { + self.deref().write(object) + } + + fn write_buf(&self, object: Kind, from: &[u8]) -> Result<ObjectId, Self::Error> { + self.deref().write_buf(object, from) + } + + fn write_stream(&self, kind: Kind, size: u64, from: impl Read) -> Result<ObjectId, Self::Error> { + self.deref().write_stream(kind, size, from) + } + } + + impl<T> crate::Write for Rc<T> + where + T: crate::Write, + { + type Error = T::Error; + + fn write(&self, object: impl WriteTo) -> Result<ObjectId, Self::Error> { + self.deref().write(object) + } + + fn write_buf(&self, object: Kind, from: &[u8]) -> Result<ObjectId, Self::Error> { + self.deref().write_buf(object, from) + } + + fn write_stream(&self, kind: Kind, size: u64, from: impl Read) -> Result<ObjectId, Self::Error> { + self.deref().write_stream(kind, size, from) + } + } + + impl<T> crate::Find for &T + where + T: crate::Find, + { + type Error = T::Error; + + fn contains(&self, id: impl AsRef<oid>) -> bool { + (*self).contains(id) + } + + fn try_find<'a>(&self, id: impl AsRef<oid>, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, Self::Error> { + (*self).try_find(id, buffer) + } + } + + impl<T> crate::Header for &T + where + T: crate::Header, + { + type Error = T::Error; + + fn try_header(&self, id: impl AsRef<oid>) -> Result<Option<Header>, Self::Error> { + (*self).try_header(id) + } + } + + impl<T> crate::Find for Rc<T> + where + T: crate::Find, + { + type Error = T::Error; + + fn contains(&self, id: impl AsRef<oid>) -> bool { + self.deref().contains(id) + } + + fn try_find<'a>(&self, id: impl AsRef<oid>, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, Self::Error> { + self.deref().try_find(id, buffer) + } + } + + impl<T> crate::Header for Rc<T> + where + T: crate::Header, + { + type Error = T::Error; + + fn try_header(&self, id: impl AsRef<oid>) -> Result<Option<Header>, Self::Error> { + self.deref().try_header(id) + } + } + + impl<T> crate::Find for Arc<T> + where + T: crate::Find, + { + type Error = T::Error; + + fn contains(&self, id: impl AsRef<oid>) -> bool { + self.deref().contains(id) + } + + fn try_find<'a>(&self, id: impl AsRef<oid>, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, Self::Error> { + self.deref().try_find(id, buffer) + } + } + + impl<T> crate::Header for Arc<T> + where + T: crate::Header, + { + type Error = T::Error; + + fn try_header(&self, id: impl AsRef<oid>) -> Result<Option<Header>, Self::Error> { + self.deref().try_header(id) + } + } +} + +mod ext { + use gix_object::{BlobRef, CommitRef, CommitRefIter, Kind, ObjectRef, TagRef, TagRefIter, TreeRef, TreeRefIter}; + + use crate::find; + + macro_rules! make_obj_lookup { + ($method:ident, $object_variant:path, $object_kind:path, $object_type:ty) => { + /// Like [`find(…)`][Self::find()], but flattens the `Result<Option<_>>` into a single `Result` making a non-existing object an error + /// while returning the desired object type. + fn $method<'a>( + &self, + id: impl AsRef<gix_hash::oid>, + buffer: &'a mut Vec<u8>, + ) -> Result<$object_type, find::existing_object::Error<Self::Error>> { + let id = id.as_ref(); + self.try_find(id, buffer) + .map_err(find::existing_object::Error::Find)? + .ok_or_else(|| find::existing_object::Error::NotFound { + oid: id.as_ref().to_owned(), + }) + .and_then(|o| o.decode().map_err(find::existing_object::Error::Decode)) + .and_then(|o| match o { + $object_variant(o) => return Ok(o), + _other => Err(find::existing_object::Error::ObjectKind { + expected: $object_kind, + }), + }) + } + }; + } + + macro_rules! make_iter_lookup { + ($method:ident, $object_kind:path, $object_type:ty, $into_iter:tt) => { + /// Like [`find(…)`][Self::find()], but flattens the `Result<Option<_>>` into a single `Result` making a non-existing object an error + /// while returning the desired iterator type. + fn $method<'a>( + &self, + id: impl AsRef<gix_hash::oid>, + buffer: &'a mut Vec<u8>, + ) -> Result<$object_type, find::existing_iter::Error<Self::Error>> { + let id = id.as_ref(); + self.try_find(id, buffer) + .map_err(find::existing_iter::Error::Find)? + .ok_or_else(|| find::existing_iter::Error::NotFound { + oid: id.as_ref().to_owned(), + }) + .and_then(|o| { + o.$into_iter() + .ok_or_else(|| find::existing_iter::Error::ObjectKind { + expected: $object_kind, + }) + }) + } + }; + } + + /// An extension trait with convenience functions. + pub trait HeaderExt: super::Header { + /// Like [`try_header(…)`][super::Header::try_header()], but flattens the `Result<Option<_>>` into a single `Result` making a non-existing object an error. + fn header( + &self, + id: impl AsRef<gix_hash::oid>, + ) -> Result<crate::find::Header, find::existing::Error<Self::Error>> { + let id = id.as_ref(); + self.try_header(id) + .map_err(find::existing::Error::Find)? + .ok_or_else(|| find::existing::Error::NotFound { oid: id.to_owned() }) + } + } + + impl<T: super::Header> HeaderExt for T {} + + /// An extension trait with convenience functions. + pub trait FindExt: super::Find { + /// Like [`try_find(…)`][super::Find::try_find()], but flattens the `Result<Option<_>>` into a single `Result` making a non-existing object an error. + fn find<'a>( + &self, + id: impl AsRef<gix_hash::oid>, + buffer: &'a mut Vec<u8>, + ) -> Result<gix_object::Data<'a>, find::existing::Error<Self::Error>> { + let id = id.as_ref(); + self.try_find(id, buffer) + .map_err(find::existing::Error::Find)? + .ok_or_else(|| find::existing::Error::NotFound { oid: id.to_owned() }) + } + + make_obj_lookup!(find_commit, ObjectRef::Commit, Kind::Commit, CommitRef<'a>); + make_obj_lookup!(find_tree, ObjectRef::Tree, Kind::Tree, TreeRef<'a>); + make_obj_lookup!(find_tag, ObjectRef::Tag, Kind::Tag, TagRef<'a>); + make_obj_lookup!(find_blob, ObjectRef::Blob, Kind::Blob, BlobRef<'a>); + make_iter_lookup!(find_commit_iter, Kind::Commit, CommitRefIter<'a>, try_into_commit_iter); + make_iter_lookup!(find_tree_iter, Kind::Tree, TreeRefIter<'a>, try_into_tree_iter); + make_iter_lookup!(find_tag_iter, Kind::Tag, TagRefIter<'a>, try_into_tag_iter); + } + + impl<T: super::Find> FindExt for T {} +} +pub use ext::{FindExt, HeaderExt}; + +use crate::find; |