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

use std::collections::VecDeque;

use crate::db::{entry::Entry, group::Group};

/// An owned node in the database tree structure which can either be an Entry or Group
#[derive(Debug, Eq, PartialEq, Clone)]
#[cfg_attr(feature = "serialization", derive(serde::Serialize))]
pub enum Node {
    Group(Group),
    Entry(Entry),
}

impl Node {
    pub fn as_ref<'a>(&'a self) -> NodeRef<'a> {
        self.into()
    }

    pub fn as_mut<'a>(&'a mut self) -> NodeRefMut<'a> {
        self.into()
    }
}

impl From<Entry> for Node {
    fn from(entry: Entry) -> Self {
        Node::Entry(entry)
    }
}

impl From<Group> for Node {
    fn from(group: Group) -> Self {
        Node::Group(group)
    }
}

/// A shared reference to a node in the database tree structure which can either point to an Entry or a Group
#[derive(Debug, Eq, PartialEq)]
pub enum NodeRef<'a> {
    Group(&'a Group),
    Entry(&'a Entry),
}

impl<'a> std::convert::From<&'a Node> for NodeRef<'a> {
    fn from(n: &'a Node) -> Self {
        match n {
            Node::Group(g) => NodeRef::Group(g),
            Node::Entry(e) => NodeRef::Entry(e),
        }
    }
}

/// An exclusive mutable reference to a node in the database tree structure which can either point to an Entry or a Group
#[derive(Debug, Eq, PartialEq)]
pub enum NodeRefMut<'a> {
    Group(&'a mut Group),
    Entry(&'a mut Entry),
}

impl<'a> std::convert::From<&'a mut Node> for NodeRefMut<'a> {
    fn from(n: &'a mut Node) -> Self {
        match n {
            Node::Group(g) => NodeRefMut::Group(g),
            Node::Entry(e) => NodeRefMut::Entry(e),
        }
    }
}

/// An iterator over Group and Entry references
pub struct NodeIter<'a> {
    queue: VecDeque<NodeRef<'a>>,
}

impl<'a> NodeIter<'a> {
    pub fn new(queue: VecDeque<NodeRef<'a>>) -> Self {
        Self { queue }
    }
}

impl<'a> Iterator for NodeIter<'a> {
    type Item = NodeRef<'a>;

    fn next(&mut self) -> Option<NodeRef<'a>> {
        let head = self.queue.pop_front()?;

        if let NodeRef::Group(ref g) = head {
            self.queue.extend(g.children.iter().map(|n| n.into()))
        }

        Some(head)
    }
}