partiql_common/
node.rs

1use indexmap::IndexMap;
2use std::hash::Hash;
3
4#[cfg(feature = "serde")]
5use serde::{Deserialize, Serialize};
6
7pub type NodeMap<T> = IndexMap<NodeId, T>;
8
9pub trait IdAnnotated<T: Copy> {
10    fn id(&self) -> T;
11}
12
13#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
14#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
15pub struct NodeId(pub u32);
16
17impl IdAnnotated<NodeId> for NodeId {
18    fn id(&self) -> NodeId {
19        *self
20    }
21}
22
23#[derive(Debug)]
24/// Auto-incrementing [`NodeIdGenerator`]
25pub struct AutoNodeIdGenerator {
26    next_id: NodeId,
27}
28
29impl Default for AutoNodeIdGenerator {
30    fn default() -> Self {
31        AutoNodeIdGenerator { next_id: NodeId(1) }
32    }
33}
34
35/// A provider of 'fresh' [`NodeId`]s.
36pub trait NodeIdGenerator {
37    /// Provides a 'fresh' [`NodeId`].
38    fn next_id(&mut self) -> NodeId;
39}
40
41impl NodeIdGenerator for AutoNodeIdGenerator {
42    #[inline]
43    fn next_id(&mut self) -> NodeId {
44        let mut next = NodeId(&self.next_id.0 + 1);
45        std::mem::swap(&mut self.next_id, &mut next);
46        next
47    }
48}
49
50/// A provider of [`NodeId`]s that are always `0`; Useful for testing
51#[derive(Default)]
52pub struct NullIdGenerator {}
53
54impl NodeIdGenerator for NullIdGenerator {
55    fn next_id(&mut self) -> NodeId {
56        NodeId(0)
57    }
58}
59
60#[cfg(test)]
61mod tests {
62    use crate::node::{AutoNodeIdGenerator, NodeIdGenerator};
63
64    #[test]
65    fn unique_ids() {
66        let mut gen = AutoNodeIdGenerator::default();
67
68        let ids: Vec<_> = std::iter::repeat_with(|| gen.next_id()).take(15).collect();
69        dbg!(&ids);
70        for i in 0..ids.len() {
71            for j in i + 1..ids.len() {
72                assert_ne!(ids[i], ids[j]);
73            }
74        }
75    }
76}
partiql_common/node.rs

partiql_common/
node.rs
