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
use crate::{data, find};
/// 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][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;
/// Find an object matching `id` in the database while placing its raw, undecoded 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 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<git_hash::oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl crate::cache::DecodeEntry,
) -> Result<Option<data::Object<'a>>, Self::Error>;
/// 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 the object database may have no notion of packs and thus always returns `None`.
fn location_by_oid(&self, id: impl AsRef<git_hash::oid>, buf: &mut Vec<u8>) -> Option<crate::bundle::Location>;
/// Find the bundle matching `pack_id`, or `None` if there is no such pack.
///
/// _Note_ that the object database may have no notion of packs and thus always returns `None`.
fn bundle_by_pack_id(&self, pack_id: u32) -> Option<&crate::Bundle>;
/// 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 a [`data::Object`].
///
/// # 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.
fn entry_by_location(&self, location: &crate::bundle::Location) -> Option<find::Entry<'_>>;
}
mod ext {
use git_object::{BlobRef, CommitRef, CommitRefIter, Kind, ObjectRef, TagRef, TagRefIter, TreeRef, TreeRefIter};
use crate::{data, 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 $method<'a>(
&self,
id: impl AsRef<git_hash::oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl crate::cache::DecodeEntry,
) -> Result<$object_type, find::existing_object::Error<Self::Error>> {
let id = id.as_ref();
self.try_find(id, buffer, pack_cache)
.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 $method<'a>(
&self,
id: impl AsRef<git_hash::oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl crate::cache::DecodeEntry,
) -> Result<$object_type, find::existing_iter::Error<Self::Error>> {
let id = id.as_ref();
self.try_find(id, buffer, pack_cache)
.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 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<git_hash::oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl crate::cache::DecodeEntry,
) -> Result<data::Object<'a>, find::existing::Error<Self::Error>> {
let id = id.as_ref();
self.try_find(id, buffer, pack_cache)
.map_err(find::existing::Error::Find)?
.ok_or_else(|| find::existing::Error::NotFound {
oid: id.as_ref().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::Blob, 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;
mod find_impls {
use std::ops::Deref;
use git_hash::oid;
use crate::{bundle::Location, data::Object, find, Bundle};
impl<T> super::Find for std::sync::Arc<T>
where
T: super::Find,
{
type Error = T::Error;
fn try_find<'a>(
&self,
id: impl AsRef<oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl crate::cache::DecodeEntry,
) -> Result<Option<Object<'a>>, Self::Error> {
self.deref().try_find(id, buffer, pack_cache)
}
fn location_by_oid(&self, id: impl AsRef<oid>, buf: &mut Vec<u8>) -> Option<Location> {
self.deref().location_by_oid(id, buf)
}
fn bundle_by_pack_id(&self, pack_id: u32) -> Option<&Bundle> {
self.deref().bundle_by_pack_id(pack_id)
}
fn entry_by_location(&self, object: &crate::bundle::Location) -> Option<find::Entry<'_>> {
self.deref().entry_by_location(object)
}
}
impl<T> super::Find for Box<T>
where
T: super::Find,
{
type Error = T::Error;
fn try_find<'a>(
&self,
id: impl AsRef<oid>,
buffer: &'a mut Vec<u8>,
pack_cache: &mut impl crate::cache::DecodeEntry,
) -> Result<Option<Object<'a>>, Self::Error> {
self.deref().try_find(id, buffer, pack_cache)
}
fn location_by_oid(&self, id: impl AsRef<oid>, buf: &mut Vec<u8>) -> Option<Location> {
self.deref().location_by_oid(id, buf)
}
fn bundle_by_pack_id(&self, pack_id: u32) -> Option<&Bundle> {
self.deref().bundle_by_pack_id(pack_id)
}
fn entry_by_location(&self, location: &crate::bundle::Location) -> Option<find::Entry<'_>> {
self.deref().entry_by_location(location)
}
}
}