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

// Copyright 2019-2024 ChainSafe Systems
// SPDX-License-Identifier: Apache-2.0, MIT

use super::*;
use cid::Cid;

#[cfg(doc)]
use std::collections::HashSet;

/// A hash set implemented as a `HashMap` where the value is `()`.
///
/// See also [`HashSet`].
#[derive(Default, Clone, Debug, PartialEq, Eq)]
pub struct CidHashSet {
    inner: CidHashMap<()>,
}

impl CidHashSet {
    /// Creates an empty `HashSet`.
    ///
    /// See also [`HashSet::new`].
    pub fn new() -> Self {
        Self::default()
    }

    /// Adds a value to the set.
    ///
    /// Returns whether the value was newly inserted.
    ///
    /// See also [`HashSet::insert`].
    pub fn insert(&mut self, cid: Cid) -> bool {
        self.inner.insert(cid, ()).is_none()
    }

    /// Returns the number of elements.
    pub fn len(&self) -> usize {
        self.inner.len()
    }

    /// Returns `true` if the set contains a `Cid`.
    pub fn contains(&self, cid: &Cid) -> bool {
        self.inner.contains_key(cid)
    }

    /// Removes a `Cid` from the set. Returns whether the value was present in the set.
    pub fn remove(&mut self, cid: &Cid) -> bool {
        self.inner.remove(cid).is_some()
    }

    /// Returns `true` if the set is empty.
    pub fn is_empty(&self) -> bool {
        self.inner.is_empty()
    }
}

////////////////////
// Collection Ops //
////////////////////

impl Extend<Cid> for CidHashSet {
    fn extend<T: IntoIterator<Item = Cid>>(&mut self, iter: T) {
        self.inner.extend(iter.into_iter().map(|it| (it, ())))
    }
}

impl FromIterator<Cid> for CidHashSet {
    fn from_iter<T: IntoIterator<Item = Cid>>(iter: T) -> Self {
        let mut this = Self::new();
        this.extend(iter);
        this
    }
}

pub struct IntoIter {
    inner: hash_map::IntoIter<()>,
}

impl Iterator for IntoIter {
    type Item = Cid;

    fn next(&mut self) -> Option<Self::Item> {
        self.inner.next().map(|(it, ())| it)
    }

    fn size_hint(&self) -> (usize, Option<usize>) {
        self.inner.size_hint()
    }
}

impl IntoIterator for CidHashSet {
    type Item = Cid;

    type IntoIter = IntoIter;

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