gluesql 0.3.0

GlueSQL - Open source SQL database engine fully written in Rust with pure functional execution layer, easily swappable storage and web assembly support!
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

use im_rc::{HashMap, HashSet};
use itertools::Itertools;
use std::cmp::Ordering;
use std::rc::Rc;

use sqlparser::ast::Function;

use crate::utils::{IndexMap, Vector};

use super::hash::GroupKey;
use crate::data::Value;
use crate::executor::context::BlendContext;
use crate::result::Result;

type Group = Rc<Vec<GroupKey>>;
type ValuesMap<'a> = HashMap<&'a Function, Value>;

pub struct State<'a> {
    index: usize,
    group: Group,
    values: IndexMap<(Group, &'a Function), (usize, Value)>,
    groups: HashSet<Group>,
    contexts: Vector<Rc<BlendContext<'a>>>,
}

impl<'a> State<'a> {
    pub fn new() -> Self {
        State {
            index: 0,
            group: Rc::new(vec![GroupKey::Null]),
            values: IndexMap::new(),
            groups: HashSet::new(),
            contexts: Vector::new(),
        }
    }

    pub fn apply(self, index: usize, group: Vec<GroupKey>, context: Rc<BlendContext<'a>>) -> Self {
        let group = Rc::new(group);
        let (groups, contexts) = if self.groups.contains(&group) {
            (self.groups, self.contexts)
        } else {
            (
                self.groups.update(Rc::clone(&group)),
                self.contexts.push(context),
            )
        };

        Self {
            index,
            group,
            values: self.values,
            groups,
            contexts,
        }
    }

    fn update(self, func: &'a Function, value: Value) -> Self {
        let key = (Rc::clone(&self.group), func);
        let (values, _) = self.values.insert(key, (self.index, value));

        Self {
            index: self.index,
            group: self.group,
            values,
            groups: self.groups,
            contexts: self.contexts,
        }
    }

    fn get(&self, func: &'a Function) -> Option<&(usize, Value)> {
        let group = Rc::clone(&self.group);

        self.values.get(&(group, func))
    }

    pub fn export(self) -> Vec<(Option<ValuesMap<'a>>, Option<Rc<BlendContext<'a>>>)> {
        let size = match self.values.keys().next() {
            Some((target, _)) => match self.values.keys().position(|(group, _)| group != target) {
                Some(size) => size,
                None => self.values.len(),
            },
            None => {
                return self.contexts.into_iter().map(|c| (None, Some(c))).collect();
            }
        };

        let Self {
            values, contexts, ..
        } = self;

        values
            .into_iter()
            .map(|(k, (_, v))| (k, v))
            .chunks(size)
            .into_iter()
            .enumerate()
            .map(|(i, entries)| {
                let aggregated = entries
                    .map(|((_, func), value)| (func, value))
                    .collect::<HashMap<&'a Function, Value>>();
                let next = contexts.get(i).map(Rc::clone);

                (Some(aggregated), next)
            })
            .collect::<Vec<(Option<ValuesMap<'a>>, Option<Rc<BlendContext<'a>>>)>>()
    }

    pub fn add(self, func: &'a Function, target: &Value) -> Result<Self> {
        let value = match self.get(func) {
            Some((index, value)) => {
                if &self.index <= index {
                    return Ok(self);
                }

                target.add(value)?
            }
            None => target.clone(),
        };

        Ok(self.update(func, value))
    }

    pub fn set_max(self, func: &'a Function, target: &Value) -> Self {
        if let Some((index, value)) = self.get(func) {
            if &self.index <= index {
                return self;
            }

            match value.partial_cmp(target) {
                None | Some(Ordering::Greater) | Some(Ordering::Equal) => {
                    return self;
                }
                Some(Ordering::Less) => (),
            }
        };

        self.update(func, target.clone())
    }

    pub fn set_min(self, func: &'a Function, target: &Value) -> Self {
        if let Some((index, value)) = self.get(func) {
            if &self.index <= index {
                return self;
            }

            match value.partial_cmp(target) {
                None | Some(Ordering::Less) => {
                    return self;
                }
                Some(Ordering::Equal) | Some(Ordering::Greater) => (),
            }
        }

        self.update(func, target.clone())
    }
}