kglite 0.17.0

Pure-Rust embedded Cypher knowledge graph engine with in-memory, mmap, and disk storage, and agent-facing schema introspection
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

//! Reading one `files` entry's knobs out of its `extra` map.
//!
//! Every format's knobs arrive as untyped JSON, and every format needs the
//! same sentence when one is written with the wrong shape: which entry, which
//! key, what it must be, and what was actually there. These live here so a
//! second and third reader do not each invent their own phrasing for it.

use indexmap::IndexMap;

pub type Extra = IndexMap<String, serde_json::Value>;

/// What a value is, for an error that says what was written instead.
pub fn json_kind(v: &serde_json::Value) -> &'static str {
    match v {
        serde_json::Value::Null => "null",
        serde_json::Value::Bool(_) => "a boolean",
        serde_json::Value::Number(_) => "a number",
        serde_json::Value::String(_) => "a string",
        serde_json::Value::Array(_) => "a list",
        serde_json::Value::Object(_) => "an object",
    }
}

pub fn get_string(name: &str, extra: &Extra, key: &str) -> Result<Option<String>, String> {
    match extra.get(key) {
        None => Ok(None),
        Some(serde_json::Value::String(s)) => Ok(Some(s.clone())),
        Some(v) => Err(format!(
            "files '{name}': '{key}' must be a string, but it is {}.",
            json_kind(v)
        )),
    }
}

pub fn get_bool(name: &str, extra: &Extra, key: &str) -> Result<Option<bool>, String> {
    match extra.get(key) {
        None => Ok(None),
        Some(serde_json::Value::Bool(b)) => Ok(Some(*b)),
        Some(v) => Err(format!(
            "files '{name}': '{key}' must be true or false, but it is {}.",
            json_kind(v)
        )),
    }
}

/// A non-negative whole number. `unit` names what is being counted, so the
/// error reads as a sentence about the file rather than about JSON.
pub fn get_usize(
    name: &str,
    extra: &Extra,
    key: &str,
    unit: &str,
) -> Result<Option<usize>, String> {
    match extra.get(key) {
        None => Ok(None),
        Some(serde_json::Value::Number(n)) => match n.as_u64() {
            Some(n) => Ok(Some(n as usize)),
            None => Err(format!(
                "files '{name}': '{key}' must be a whole number of {unit} that is not negative, \
                 but it is {n}."
            )),
        },
        Some(v) => Err(format!(
            "files '{name}': '{key}' must be a whole number of {unit}, but it is {}.",
            json_kind(v)
        )),
    }
}

pub fn get_string_list(
    name: &str,
    extra: &Extra,
    key: &str,
) -> Result<Option<Vec<String>>, String> {
    let Some(v) = extra.get(key) else {
        return Ok(None);
    };
    let serde_json::Value::Array(items) = v else {
        return Err(format!(
            "files '{name}': '{key}' must be a list of column names, but it is {}.",
            json_kind(v)
        ));
    };
    let mut out = Vec::with_capacity(items.len());
    for item in items {
        match item {
            serde_json::Value::String(s) => out.push(s.clone()),
            other => {
                return Err(format!(
                    "files '{name}': every entry of '{key}' must be a column name, but one is {}.",
                    json_kind(other)
                ))
            }
        }
    }
    Ok(Some(out))
}

pub fn get_string_map(
    name: &str,
    extra: &Extra,
    key: &str,
) -> Result<Option<Vec<(String, String)>>, String> {
    let Some(v) = extra.get(key) else {
        return Ok(None);
    };
    let serde_json::Value::Object(map) = v else {
        return Err(format!(
            "files '{name}': '{key}' must be an object of column name → text, but it is {}.",
            json_kind(v)
        ));
    };
    let mut out = Vec::with_capacity(map.len());
    for (column, value) in map {
        match value {
            serde_json::Value::String(s) => out.push((column.clone(), s.clone())),
            other => {
                return Err(format!(
                    "files '{name}': '{key}' entry '{column}' must be text, but it is {}.",
                    json_kind(other)
                ))
            }
        }
    }
    Ok(Some(out))
}

/// The first name in `names` that an earlier entry already used.
pub fn first_duplicate(names: &[String]) -> Option<&str> {
    for (i, name) in names.iter().enumerate() {
        if names[..i].iter().any(|earlier| earlier == name) {
            return Some(name);
        }
    }
    None
}