moogle 0.4.4

data structures for relational code
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

use crate::id::IdLike;
use crate::methods::{EvictSet, ViewSet};

use std::collections::BTreeMap;

#[derive(Clone, Eq, Ord, PartialEq, PartialOrd, Hash)]
pub(crate) struct ToOne<K: IdLike, V: IdLike>(pub(crate) BTreeMap<K, V>);

impl<K: IdLike, V: IdLike> ToOne<K, V> {
    pub fn keys<'a>(&'a self) -> impl 'a+DoubleEndedIterator<Item=K> { 
        self.0.keys().map(|k| *k) 
    }
    pub fn iter<'a>(&'a self) -> impl 'a+DoubleEndedIterator<Item=(K, V)> { 
        self.0.iter().map(|(k, v)| (*k, *v) ) 
    }
    pub fn values<'a>(&'a self) -> impl 'a+DoubleEndedIterator<Item=V> { 
        self.0.values().map(|v| *v ) 
    }
}

impl<'a, K: IdLike, V: IdLike> ToOne<K, V> {
    pub fn new() -> Self { ToOne(BTreeMap::new()) }

    pub fn insert(&mut self, key: K, value: V, on_evict: impl FnOnce(K, V)) -> Option<V> { 
        match self.0.get_mut(&key) {
            Some(x) => {
                if *x == value {
                    // skip on-evict callback, as we would just immediately put the value back into the opposed data structure
                    // but to caller, pretend we evicted
                    return Some(value)
                }

                let mut old = value;
                std::mem::swap(x, &mut old);
                on_evict(key, old);
                Some(old)
            }
            None => {
                self.0.insert(key, value);
                None
            }
        }
    }

    pub fn expunge(&mut self, key: K, on_evict: impl FnOnce(K, V)) -> Option<V> { 
        let value = self.0.remove(&key);
        match value {
            Some(x) => { on_evict(key, x); Some(x) }
            None => None
        }
    }

    pub fn remove(&mut self, key: K, value: V, on_evict: impl FnOnce(K, V)) -> Option<V> {
        if self.0.get(&key) == Some(&value) {
            on_evict(key, value);
            self.0.remove(&key)
        } else {
            None
        }
    }

    pub fn get(&self, key: K) -> VOne<'a, K, V> { VOne(self.0.get(&key).map(|x| *x), ::std::marker::PhantomData) }
    pub fn contains_key(&self, key: K) -> bool { self.0.contains_key(&key) }
    pub fn len(&self) -> usize { self.0.len() }
}

pub(crate) struct VOne<'a, K: IdLike, V: IdLike>(Option<V>, ::std::marker::PhantomData<&'a *const K>);
pub(crate) struct MOne<'a, K: IdLike, V: IdLike>(K, &'a mut ToOne<K, V>);  

impl <'a, K: IdLike, V: IdLike> VOne<'a, K, V> {
    pub fn as_option(&self) -> Option<V> { self.0 }
}

impl<'a, K: IdLike, V: IdLike> EvictSet<'a, K, V> for MOne<'a, K, V> {
    fn insert(&mut self, v: V, on_evict: impl FnOnce(K, V)) -> Option<V> { 
        self.1.insert(self.0, v, on_evict)
    }

    fn remove(&mut self, v: V, on_evict: impl FnOnce(K, V)) -> Option<V> { 
        self.1.remove(self.0, v, on_evict)
    }
}

impl<'a, K: IdLike, V: IdLike> ViewSet<'a, V> for VOne<'a, K, V> {
    type Iter = impl 'a+DoubleEndedIterator<Item=V>;

    fn contains(&self, v: V) -> bool {
        match self.0 {
            None => false,
            Some(x) => x == v,
        }
    }

    fn len(&self) -> usize { 
        match self.0 {
            None => 0,
            Some(_) => 1,
        }
    }

    fn iter(&'a self) -> Self::Iter { 
        self.0.iter().map(|v| *v)
    }
}

impl<'a, K: IdLike, V: IdLike> ViewSet<'a, V> for MOne<'a, K, V> {
    type Iter = impl 'a+DoubleEndedIterator<Item=V>;

    fn contains(&self, v: V) -> bool { 
        match self.1.0.get(&self.0) {
            None => false,
            Some(x) => *x == v,
        }
    }

    fn len(&self) -> usize { 
        match self.1.0.get(&self.0) {
            None => 0,
            Some(_) => 1,
        }
    }

    fn iter(&'a self) -> Self::Iter { 
        self.1.0.get(&self.0).map(|x| *x).into_iter()
    }
}

// == Standard traits ==
impl<A: IdLike, B: IdLike> IntoIterator for ToOne<A, B> {
    type Item = (A, B);

    type IntoIter = impl DoubleEndedIterator<Item=(A, B)>;

    fn into_iter(self) -> Self::IntoIter {
        self.0.into_iter()
    }
}