harmos-storage 0.1.7

Harmos storage: durable journals, snapshots and Arrow-backed stream storage.
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

/* ***
 *
 * Harmos
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * ***
 */

/* === Modules === */

/* === Re-Exports === */

/* === Imports === */

// Standard Library Imports

// Third Party Imports

// Local Imports
use super::*;

/* === Constants === */

/* === Macros === */

/* === Type Aliases === */

/* === Structs === */

/* === Enums === */

/* === Traits === */

/* === Implementations === */

impl RecordWriteBytes for RecordWrite<'_> {
    fn encoded_bytes(&self, history: &crate::StoreHistory) -> Result<usize> {
        let value = StoredRecord {
            position: StorageCursor {
                history: history.clone(),
                sequence: u64::MAX,
            },
            schema: self.schema.clone(),
            scope: self.scope.cloned(),
            item: self.item.clone(),
            source: self.source.cloned(),
            source_time: self.source_time,
            payload: self.payload,
        };
        encoded_size(&value)
    }
}

impl RecordWriteBytes for RecordInput {
    fn encoded_bytes(&self, history: &crate::StoreHistory) -> Result<usize> {
        self.borrowed().encoded_bytes(history)
    }
}

impl Drop for WriteWaiter {
    fn drop(&mut self) {
        let counter = if self.measurement { &self.inner.measurement_waiting } else { &self.inner.control_waiting };
        counter.fetch_sub(1, std::sync::atomic::Ordering::SeqCst);
        self.inner.notify();
    }
}

impl Drop for Admission {
    fn drop(&mut self) {
        if self.active {
            {
                let mut state = self.inner.state.lock().unwrap();
                state.reserved = 0;
                state.reserved_batches = 0;
                state.collect();
            }
            self.inner.notify();
        }
    }
}

impl Write for Counter {
    fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
        self.0 = self.0.checked_add(bytes.len()).ok_or_else(|| io::Error::other("encoded size overflow"))?;
        Ok(bytes.len())
    }

    fn flush(&mut self) -> io::Result<()> {
        Ok(())
    }
}

/* === Public Functions === */

pub fn encoded_size<T: Serialize + ?Sized>(value: &T) -> Result<usize> {
    let mut counter = Counter(0);
    serde_json::to_writer(&mut counter, value).map_err(|_| Error::InvalidInput {
        field: "storage payload",
        reason: "cannot measure encoded size",
    })?;
    Ok(counter.0)
}

pub(crate) fn recovery_encoded_bound(payload: usize, history: &crate::StoreHistory, data_history: &crate::StoreHistory) -> Result<usize> {
    let entry = RecoveryEntry {
        required_data: StorageCursor {
            history: data_history.clone(),
            sequence: u64::MAX,
        },
        position: RecoveryPosition {
            history: history.clone(),
            sequence: u64::MAX,
        },
        payload: Vec::new(),
    };
    let encoded = payload
        .checked_div(3)
        .and_then(|groups| groups.checked_mul(4))
        .and_then(|bytes| {
            bytes.checked_add(match payload % 3 {
                0 => 0,
                1 => 2,
                _ => 3,
            })
        })
        .ok_or(Error::InvalidInput {
            field: "managed recovery",
            reason: "encoded size overflow",
        })?;
    let snapshot = RecoverySnapshot {
        required_data: entry.required_data.clone(),
        through: entry.position.clone(),
        payload: Vec::new(),
    };
    let header = encoded_size(&entry)?.max(encoded_size(&snapshot)?);
    header.checked_add(encoded).ok_or(Error::InvalidInput {
        field: "managed recovery",
        reason: "encoded size overflow",
    })
}

/* === Private Functions === */

/* === Tests === */