dbstruct/traits/
data_store.rs

1#![allow(clippy::type_complexity)]
2//! The traits used by the wrapper to operate on the database.
3use core::fmt;
4use std::ops::RangeBounds;
5
6use serde::de::DeserializeOwned;
7use serde::Serialize;
8
9/// Base trait needed by every wrapper. It is usually more convenient to implement
10/// [`ByteStore`][super::byte_store::ByteStore] instead.
11pub trait DataStore {
12    type DbError: fmt::Debug;
13    fn get<K, V>(&self, key: &K) -> Result<Option<V>, crate::Error<Self::DbError>>
14    where
15        K: Serialize,
16        V: DeserializeOwned;
17    fn remove<K, V>(&self, key: &K) -> Result<Option<V>, crate::Error<Self::DbError>>
18    where
19        K: Serialize,
20        V: DeserializeOwned;
21    fn insert<'a, K, V, OwnedV>(
22        &self,
23        key: &'a K,
24        val: &'a V,
25    ) -> Result<Option<OwnedV>, crate::Error<Self::DbError>>
26    where
27        K: Serialize,
28        V: Serialize + ?Sized,
29        OwnedV: std::borrow::Borrow<V> + DeserializeOwned;
30}
31
32/// This trait enables wrapper to provide `update` and `conditional` update.
33/// It is usually more convenient to implement
34/// [`byte_store::Atomic`][super::byte_store::Atomic] instead.
35pub trait Atomic: DataStore {
36    fn atomic_update<K, V>(
37        &self,
38        key: &K,
39        op: impl FnMut(V) -> V + Clone,
40    ) -> Result<(), crate::Error<Self::DbError>>
41    where
42        K: Serialize,
43        V: Serialize + DeserializeOwned;
44    /// On error the update is aborted
45    fn conditional_update<K, V>(
46        &self,
47        key: &K,
48        new: &V,
49        expected: &V,
50    ) -> Result<(), crate::Error<Self::DbError>>
51    where
52        K: Serialize + ?Sized,
53        V: Serialize + ?Sized;
54}
55
56/// This trait needed for the Vec wrapper. It is usually more convenient to implement
57/// [`byte_store::Ordered`][super::byte_store::Ordered] instead.
58///
59/// You can deserialize to a different key than you serialize too.
60/// This is useful when using `get_lt` an `InKey` that borrows data. As
61/// you need to deserialize to a type owning all its data.
62pub trait Ordered: DataStore {
63    /// Retrieve the next key and value from the Tree after the provided key.
64    ///
65    /// ### Note
66    /// The order follows the `Ord` implementation for `Vec<u8>`:
67    /// [] < [0] < [255] < [255, 0] < [255, 255] ...
68    /// To retain the ordering of numerical types use big endian representation
69    fn get_lt<InKey, OutKey, Value>(
70        &self,
71        key: &InKey,
72    ) -> Result<Option<(OutKey, Value)>, crate::Error<Self::DbError>>
73    where
74        InKey: Serialize,
75        OutKey: Serialize + DeserializeOwned,
76        Value: Serialize + DeserializeOwned;
77
78    /// Retrieve the previous key and value from the Tree before the provided key.
79    ///
80    /// ### Note
81    /// The order follows the `Ord` implementation for `Vec<u8>`:
82    /// [] < [0] < [255] < [255, 0] < [255, 255] ...
83    /// To retain the ordering of numerical types use big endian representation
84    fn get_gt<InKey, OutKey, Value>(
85        &self,
86        key: &InKey,
87    ) -> Result<Option<(OutKey, Value)>, crate::Error<Self::DbError>>
88    where
89        InKey: Serialize,
90        OutKey: Serialize + DeserializeOwned,
91        Value: Serialize + DeserializeOwned;
92}
93
94/// This trait expand the functionality of the Map wrapper. It is usually more
95/// convenient to implement [`byte_store::Ranged`][super::byte_store::Ranged]
96/// instead.
97///
98/// You can deserialize to a different key than you serialize too. This is
99/// useful when using range an `InKey` that borrows data. As you need to
100/// deserialize to a type owning all its data.
101pub trait Ranged: DataStore {
102    fn range<InKey, OutKey, Value>(
103        &self,
104        range: impl RangeBounds<InKey>,
105    ) -> Result<
106        impl Iterator<Item = Result<(OutKey, Value), crate::Error<Self::DbError>>>,
107        crate::Error<Self::DbError>,
108    >
109    where
110        InKey: Serialize,
111        OutKey: Serialize + DeserializeOwned,
112        Value: Serialize + DeserializeOwned;
113}
dbstruct/traits/data_store.rs

dbstruct/traits/
data_store.rs
