pagedb 0.1.0-beta.6

Encrypted, portable, embedded page store with B+ tree and segment-file surfaces.
Documentation 
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

use pagedb::vfs::memory::MemVfs;
use pagedb::{Db, OpenOptions, PagedbError, RealmId};

const PAGE: usize = 4096;

async fn open() -> Db<MemVfs> {
    Db::open(
        MemVfs::new(),
        [9u8; 32],
        PAGE,
        RealmId::new([1; 16]),
        OpenOptions::default(),
    )
    .await
    .unwrap()
}

#[tokio::test(flavor = "current_thread")]
async fn counter_starts_at_zero() {
    let db = open().await;
    let mut w = db.begin_write().await.unwrap();
    {
        let c = w.counter("seq").unwrap();
        assert_eq!(c.get().await.unwrap(), 0);
    }
    w.commit().await.unwrap();
}

#[tokio::test(flavor = "current_thread")]
async fn increment_round_trip() {
    let db = open().await;
    {
        let mut w = db.begin_write().await.unwrap();
        {
            let mut c = w.counter("seq").unwrap();
            let v = c.increment_by(1).await.unwrap();
            assert_eq!(v, 1);
            let v = c.increment_by(5).await.unwrap();
            assert_eq!(v, 6);
        }
        w.commit().await.unwrap();
    }
    let mut w = db.begin_write().await.unwrap();
    let c = w.counter("seq").unwrap();
    assert_eq!(c.get().await.unwrap(), 6);
}

#[tokio::test(flavor = "current_thread")]
async fn counters_persist_across_reopen() {
    let vfs = MemVfs::new();
    {
        let db = Db::open(
            vfs.clone(),
            [9u8; 32],
            PAGE,
            RealmId::new([1; 16]),
            OpenOptions::default(),
        )
        .await
        .unwrap();
        let mut w = db.begin_write().await.unwrap();
        {
            let mut c = w.counter("seq").unwrap();
            c.increment_by(1234).await.unwrap();
        }
        w.commit().await.unwrap();
    }
    let db = Db::open(
        vfs,
        [9u8; 32],
        PAGE,
        RealmId::new([1; 16]),
        OpenOptions::default(),
    )
    .await
    .unwrap();
    let mut w = db.begin_write().await.unwrap();
    let c = w.counter("seq").unwrap();
    assert_eq!(c.get().await.unwrap(), 1234);
}

#[tokio::test(flavor = "current_thread")]
async fn multiple_counters_independent() {
    let db = open().await;
    let mut w = db.begin_write().await.unwrap();
    {
        let mut a = w.counter("a").unwrap();
        a.increment_by(10).await.unwrap();
    }
    {
        let mut b = w.counter("b").unwrap();
        b.increment_by(20).await.unwrap();
    }
    {
        let a = w.counter("a").unwrap();
        assert_eq!(a.get().await.unwrap(), 10);
    }
    {
        let b = w.counter("b").unwrap();
        assert_eq!(b.get().await.unwrap(), 20);
    }
    w.commit().await.unwrap();
}

#[tokio::test(flavor = "current_thread")]
async fn monotonic_set_smaller_fails() {
    let db = open().await;
    let mut w = db.begin_write().await.unwrap();
    let mut c = w.counter("seq").unwrap();
    c.set(100).await.unwrap();
    let err = c.set(50).await.err().unwrap();
    assert!(matches!(err, PagedbError::Aborted));
}

#[tokio::test(flavor = "current_thread")]
async fn abort_discards_increments() {
    let db = open().await;
    {
        let mut w = db.begin_write().await.unwrap();
        {
            let mut c = w.counter("seq").unwrap();
            c.increment_by(7).await.unwrap();
        }
        w.abort().await;
    }
    let mut w = db.begin_write().await.unwrap();
    let c = w.counter("seq").unwrap();
    assert_eq!(c.get().await.unwrap(), 0);
}

#[tokio::test(flavor = "current_thread")]
async fn increment_overflow_rejected() {
    let db = open().await;
    let mut w = db.begin_write().await.unwrap();
    let mut c = w.counter("seq").unwrap();
    c.set(u64::MAX).await.unwrap();
    let err = c.increment_by(1).await.err().unwrap();
    assert!(matches!(err, PagedbError::NonceCounterExhausted));
}

#[tokio::test(flavor = "current_thread")]
async fn many_increments_persist_with_intermediate_flush() {
    let vfs = MemVfs::new();
    // One entry point for both the first iteration (which bootstraps) and the
    // rest (which reopen): `Db::open` decides from what is on disk.
    for _ in 0..10u64 {
        let db = Db::open(
            vfs.clone(),
            [9u8; 32],
            PAGE,
            RealmId::new([1; 16]),
            OpenOptions::default(),
        )
        .await
        .unwrap();
        let mut w = db.begin_write().await.unwrap();
        {
            let mut c = w.counter("seq").unwrap();
            for _ in 0..100u64 {
                c.increment_by(1).await.unwrap();
            }
        }
        w.commit().await.unwrap();
        drop(db);
    }
    let db = Db::open(
        vfs,
        [9u8; 32],
        PAGE,
        RealmId::new([1; 16]),
        OpenOptions::default(),
    )
    .await
    .unwrap();
    let mut w = db.begin_write().await.unwrap();
    let c = w.counter("seq").unwrap();
    assert_eq!(c.get().await.unwrap(), 1000);
}