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

// Copyright 2019 Parity Technologies (UK) Ltd.
// Copyright 2023 litep2p developers
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use crate::PeerId;

use bytes::Bytes;
use multihash::Multihash;

use std::{borrow::Borrow, time::Instant};

/// The (opaque) key of a record.
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
pub struct Key(Bytes);

impl Key {
    /// Creates a new key from the bytes of the input.
    pub fn new<K: AsRef<[u8]>>(key: &K) -> Self {
        Key(Bytes::copy_from_slice(key.as_ref()))
    }

    /// Copies the bytes of the key into a new vector.
    pub fn to_vec(&self) -> Vec<u8> {
        Vec::from(&self.0[..])
    }
}

impl From<Key> for Vec<u8> {
    fn from(k: Key) -> Vec<u8> {
        Vec::from(&k.0[..])
    }
}

impl Borrow<[u8]> for Key {
    fn borrow(&self) -> &[u8] {
        &self.0[..]
    }
}

impl AsRef<[u8]> for Key {
    fn as_ref(&self) -> &[u8] {
        &self.0[..]
    }
}

impl From<Vec<u8>> for Key {
    fn from(v: Vec<u8>) -> Key {
        Key(Bytes::from(v))
    }
}

impl From<Multihash> for Key {
    fn from(m: Multihash) -> Key {
        Key::from(m.to_bytes())
    }
}

/// A record stored in the DHT.
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct Record {
    /// Key of the record.
    pub key: Key,

    /// Value of the record.
    pub value: Vec<u8>,

    /// The (original) publisher of the record.
    pub publisher: Option<PeerId>,

    /// The expiration time as measured by a local, monotonic clock.
    pub expires: Option<Instant>,
}

impl Record {
    /// Creates a new record for insertion into the DHT.
    pub fn new<K>(key: K, value: Vec<u8>) -> Self
    where
        K: Into<Key>,
    {
        Record {
            key: key.into(),
            value,
            publisher: None,
            expires: None,
        }
    }

    /// Checks whether the record is expired w.r.t. the given `Instant`.
    pub fn is_expired(&self, now: Instant) -> bool {
        self.expires.map_or(false, |t| now >= t)
    }
}

/// A record either received by the given peer or retrieved from the local
/// record store.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PeerRecord {
    /// The peer from whom the record was received. `None` if the record was
    /// retrieved from local storage.
    pub peer: Option<PeerId>,

    pub record: Record,
}