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

//!
//! A double-key style of `Mapx`.
//!
//! NOTE:
//! - Both keys and values will be encoded in this structure
//!

#[cfg(test)]
mod test;

use crate::{
    basic_multi_key::mapx_raw::MapxRawMk,
    common::ende::{KeyEnDe, ValueEnDe},
};
use ruc::*;
use serde::{Deserialize, Serialize};
use std::{
    marker::PhantomData,
    ops::{Deref, DerefMut},
};

const KEY_SIZE: usize = 2;

/// A map structure with two-level keys.
#[derive(Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Debug)]
#[serde(bound = "")]
pub struct MapxDk<K1, K2, V> {
    inner: MapxRawMk,
    p1: PhantomData<K1>,
    p2: PhantomData<K2>,
    p3: PhantomData<V>,
}

impl<K1, K2, V> MapxDk<K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    #[inline(always)]
    pub fn new() -> Self {
        Self {
            inner: MapxRawMk::new(KEY_SIZE),
            p1: PhantomData,
            p2: PhantomData,
            p3: PhantomData,
        }
    }

    #[inline(always)]
    pub fn get(&self, key: &(&K1, &K2)) -> Option<V> {
        let k1 = key.0.encode();
        let k2 = key.1.encode();
        self.inner
            .get(&[&k1, &k2])
            .map(|v| pnk!(ValueEnDe::decode(&v)))
    }

    #[inline(always)]
    pub fn get_mut<'a>(
        &'a self,
        key: &'a (&'a K1, &'a K2),
    ) -> Option<ValueMut<'a, K1, K2, V>> {
        self.get(key).map(move |v| ValueMut::new(self, key, v))
    }

    #[inline(always)]
    pub fn contains_key(&self, key: &(&K1, &K2)) -> bool {
        self.get(key).is_some()
    }

    #[inline(always)]
    pub fn is_empty(&self) -> bool {
        self.inner.is_empty()
    }

    #[inline(always)]
    pub fn entry_ref<'a>(&'a self, key: &'a (&'a K1, &'a K2)) -> Entry<'a, K1, K2, V> {
        Entry { key, hdr: self }
    }

    #[inline(always)]
    pub fn insert(&self, key: &(&K1, &K2), value: &V) -> Option<V> {
        let k1 = key.0.encode();
        let k2 = key.1.encode();
        let v = value.encode();
        pnk!(self.inner.insert(&[&k1, &k2], &v))
            .map(|old_v| pnk!(ValueEnDe::decode(&old_v)))
    }

    /// Support batch removal.
    #[inline(always)]
    pub fn remove(&self, key: &(&K1, Option<&K2>)) -> Option<V> {
        let k1 = key.0.encode();
        let k2 = key.1.map(|k2| k2.encode());
        let k = if let Some(k2) = k2.as_ref() {
            vec![&k1[..], &k2[..]]
        } else {
            vec![&k1[..]]
        };
        pnk!(self.inner.remove(k.as_slice()))
            .map(|old_v| pnk!(ValueEnDe::decode(&old_v)))
    }

    #[inline(always)]
    pub fn clear(&self) {
        self.inner.clear();
    }

    #[inline(always)]
    pub fn key_size(&self) -> usize {
        self.inner.key_size()
    }
}

impl<K1, K2, V> Default for MapxDk<K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    fn default() -> Self {
        Self::new()
    }
}

#[derive(PartialEq, Eq, Debug)]
pub struct ValueMut<'a, K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    hdr: &'a MapxDk<K1, K2, V>,
    key: &'a (&'a K1, &'a K2),
    value: V,
}

impl<'a, K1, K2, V> ValueMut<'a, K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    fn new(hdr: &'a MapxDk<K1, K2, V>, key: &'a (&'a K1, &'a K2), value: V) -> Self {
        ValueMut { hdr, key, value }
    }
}

impl<'a, K1, K2, V> Drop for ValueMut<'a, K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    fn drop(&mut self) {
        pnk!(self.hdr.insert(self.key, &self.value));
    }
}

impl<'a, K1, K2, V> Deref for ValueMut<'a, K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    type Target = V;
    fn deref(&self) -> &Self::Target {
        &self.value
    }
}

impl<'a, K1, K2, V> DerefMut for ValueMut<'a, K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.value
    }
}

pub struct Entry<'a, K1, K2, V> {
    key: &'a (&'a K1, &'a K2),
    hdr: &'a MapxDk<K1, K2, V>,
}

impl<'a, K1, K2, V> Entry<'a, K1, K2, V>
where
    K1: KeyEnDe,
    K2: KeyEnDe,
    V: ValueEnDe,
{
    pub fn or_insert_ref(self, default: &'a V) -> ValueMut<'a, K1, K2, V> {
        if !self.hdr.contains_key(self.key) {
            self.hdr.insert(self.key, default);
        }
        pnk!(self.hdr.get_mut(self.key))
    }
}