linera_base/
hashed.rs

1// Copyright (c) Facebook, Inc. and its affiliates.
2// Copyright (c) Zefchain Labs, Inc.
3// SPDX-License-Identifier: Apache-2.0
4
5//! A wrapper for hashable types to memoize the hash.
6
7use std::borrow::Cow;
8
9use allocative::Allocative;
10use custom_debug_derive::Debug;
11use serde::{Deserialize, Serialize};
12
13use crate::crypto::{BcsHashable, CryptoHash};
14
15/// Wrapper type around hashed instance of `T` type.
16#[derive(Debug, Allocative)]
17pub struct Hashed<T> {
18    value: T,
19    /// Hash of the value (used as key for storage).
20    hash: CryptoHash,
21}
22
23impl<T> Hashed<T> {
24    /// Creates an instance of [`Hashed`] with the given `value`.
25    pub fn new<'de>(value: T) -> Self
26    where
27        T: BcsHashable<'de>,
28    {
29        let hash = CryptoHash::new(&value);
30        Self { value, hash }
31    }
32
33    /// Returns the hash.
34    pub fn hash(&self) -> CryptoHash {
35        self.hash
36    }
37
38    /// Returns a reference to the value, without the hash.
39    pub fn inner(&self) -> &T {
40        &self.value
41    }
42
43    /// Consumes the hashed value and returns the value without the hash.
44    pub fn into_inner(self) -> T {
45        self.value
46    }
47}
48
49impl<T: Serialize> Serialize for Hashed<T> {
50    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
51    where
52        S: serde::Serializer,
53    {
54        self.value.serialize(serializer)
55    }
56}
57
58impl<'de, T: BcsHashable<'de>> Deserialize<'de> for Hashed<T> {
59    fn deserialize<D>(deserializer: D) -> Result<Hashed<T>, D::Error>
60    where
61        D: serde::Deserializer<'de>,
62    {
63        Ok(Hashed::new(T::deserialize(deserializer)?))
64    }
65}
66
67impl<T: Clone> Clone for Hashed<T> {
68    fn clone(&self) -> Self {
69        Self {
70            value: self.value.clone(),
71            hash: self.hash,
72        }
73    }
74}
75
76impl<T: async_graphql::OutputType> async_graphql::TypeName for Hashed<T> {
77    fn type_name() -> Cow<'static, str> {
78        format!("Hashed{}", T::type_name()).into()
79    }
80}
81
82#[async_graphql::Object(cache_control(no_cache), name_type)]
83impl<T: async_graphql::OutputType + Clone> Hashed<T> {
84    #[graphql(derived(name = "hash"))]
85    async fn _hash(&self) -> CryptoHash {
86        self.hash()
87    }
88
89    #[graphql(derived(name = "value"))]
90    async fn _value(&self) -> T {
91        self.inner().clone()
92    }
93}
94
95impl<T> PartialEq for Hashed<T> {
96    fn eq(&self, other: &Self) -> bool {
97        self.hash() == other.hash()
98    }
99}
100
101impl<T> Eq for Hashed<T> {}
linera_base/hashed.rs

linera_base/
hashed.rs
