gix_object/traits.rs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303
use std::io::Write;
use crate::Kind;
/// Writing of objects to a `Write` implementation
pub trait WriteTo {
/// Write a representation of this instance to `out`.
fn write_to(&self, out: &mut dyn std::io::Write) -> std::io::Result<()>;
/// Returns the type of this object.
fn kind(&self) -> Kind;
/// Returns the size of this object's representation (the amount
/// of data which would be written by [`write_to`](Self::write_to)).
///
/// [`size`](Self::size)'s value has no bearing on the validity of
/// the object, as such it's possible for [`size`](Self::size) to
/// return a sensible value but [`write_to`](Self::write_to) to
/// fail because the object was not actually valid in some way.
fn size(&self) -> u64;
/// Returns a loose object header based on the object's data
fn loose_header(&self) -> smallvec::SmallVec<[u8; 28]> {
crate::encode::loose_header(self.kind(), self.size())
}
}
impl<T> WriteTo for &T
where
T: WriteTo,
{
fn write_to(&self, out: &mut dyn Write) -> std::io::Result<()> {
<T as WriteTo>::write_to(self, out)
}
fn kind(&self) -> Kind {
<T as WriteTo>::kind(self)
}
fn size(&self) -> u64 {
<T as WriteTo>::size(self)
}
}
mod find {
use crate::find;
/// Check if an object is present in an object store.
pub trait Exists {
/// Returns `true` if the object exists in the database.
fn exists(&self, id: &gix_hash::oid) -> bool;
}
/// Find an object in the 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 {
/// 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: &gix_hash::oid,
buffer: &'a mut Vec<u8>,
) -> Result<Option<crate::Data<'a>>, find::Error>;
}
/// Find the header of an object in the object store.
pub trait Header {
/// Find the header of the object matching `id` in the database.
///
/// Returns `Some` header if it was present, or the error that occurred during lookup.
fn try_header(&self, id: &gix_hash::oid) -> Result<Option<crate::Header>, find::Error>;
}
/// A combination of [`Find`] and [`Header`] traits to help with `dyn` trait objects.
pub trait FindObjectOrHeader: Find + Header {}
mod _impls {
use std::{ops::Deref, rc::Rc, sync::Arc};
use gix_hash::oid;
use crate::Data;
impl<T> crate::Exists for &T
where
T: crate::Exists,
{
fn exists(&self, id: &oid) -> bool {
(*self).exists(id)
}
}
impl<T> crate::FindObjectOrHeader for T where T: crate::Find + crate::FindHeader {}
impl<T> crate::Find for &T
where
T: crate::Find,
{
fn try_find<'a>(&self, id: &oid, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, crate::find::Error> {
(*self).try_find(id, buffer)
}
}
impl<T> crate::FindHeader for &T
where
T: crate::FindHeader,
{
fn try_header(&self, id: &gix_hash::oid) -> Result<Option<crate::Header>, crate::find::Error> {
(*self).try_header(id)
}
}
impl<T> crate::Exists for Box<T>
where
T: crate::Exists,
{
fn exists(&self, id: &oid) -> bool {
self.deref().exists(id)
}
}
impl<T> crate::Exists for Rc<T>
where
T: crate::Exists,
{
fn exists(&self, id: &oid) -> bool {
self.deref().exists(id)
}
}
impl<T> crate::Find for Rc<T>
where
T: crate::Find,
{
fn try_find<'a>(&self, id: &oid, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, crate::find::Error> {
self.deref().try_find(id, buffer)
}
}
impl<T> crate::FindHeader for Rc<T>
where
T: crate::FindHeader,
{
fn try_header(&self, id: &gix_hash::oid) -> Result<Option<crate::Header>, crate::find::Error> {
self.deref().try_header(id)
}
}
impl<T> crate::Find for Box<T>
where
T: crate::Find,
{
fn try_find<'a>(&self, id: &oid, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, crate::find::Error> {
self.deref().try_find(id, buffer)
}
}
impl<T> crate::FindHeader for Box<T>
where
T: crate::FindHeader,
{
fn try_header(&self, id: &gix_hash::oid) -> Result<Option<crate::Header>, crate::find::Error> {
self.deref().try_header(id)
}
}
impl<T> crate::Exists for Arc<T>
where
T: crate::Exists,
{
fn exists(&self, id: &oid) -> bool {
self.deref().exists(id)
}
}
impl<T> crate::Find for Arc<T>
where
T: crate::Find,
{
fn try_find<'a>(&self, id: &oid, buffer: &'a mut Vec<u8>) -> Result<Option<Data<'a>>, crate::find::Error> {
self.deref().try_find(id, buffer)
}
}
impl<T> crate::FindHeader for Arc<T>
where
T: crate::FindHeader,
{
fn try_header(&self, id: &gix_hash::oid) -> Result<Option<crate::Header>, crate::find::Error> {
self.deref().try_header(id)
}
}
}
mod ext {
use crate::{
find, BlobRef, CommitRef, CommitRefIter, Kind, ObjectRef, TagRef, TagRefIter, TreeRef, TreeRefIter,
};
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 $method<'a>(
&self,
id: &gix_hash::oid,
buffer: &'a mut Vec<u8>,
) -> Result<$object_type, find::existing_object::Error> {
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(|err| find::existing_object::Error::Decode {
source: err,
oid: id.as_ref().to_owned(),
})
})
.and_then(|o| match o {
$object_variant(o) => return Ok(o),
o => Err(find::existing_object::Error::ObjectKind {
oid: id.as_ref().to_owned(),
actual: o.kind(),
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 $method<'a>(
&self,
id: &gix_hash::oid,
buffer: &'a mut Vec<u8>,
) -> Result<$object_type, find::existing_iter::Error> {
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 {
oid: id.as_ref().to_owned(),
actual: o.kind,
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 header an error.
fn header(&self, id: &gix_hash::oid) -> Result<crate::Header, find::existing::Error> {
self.try_header(id)
.map_err(find::existing::Error::Find)?
.ok_or_else(|| find::existing::Error::NotFound { oid: id.to_owned() })
}
}
/// 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: &gix_hash::oid,
buffer: &'a mut Vec<u8>,
) -> Result<crate::Data<'a>, find::existing::Error> {
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 + ?Sized> FindExt for T {}
}
pub use ext::{FindExt, HeaderExt};
}
pub use find::*;