cxx_build/syntax/
set.rs

1use std::fmt::{self, Debug};
2use std::slice;
3
4pub(crate) use self::ordered::OrderedSet;
5pub(crate) use self::unordered::UnorderedSet;
6
7mod ordered {
8    use super::{Iter, UnorderedSet};
9    use std::hash::Hash;
10
11    pub(crate) struct OrderedSet<T> {
12        set: UnorderedSet<T>,
13        vec: Vec<T>,
14    }
15
16    impl<'a, T> OrderedSet<&'a T>
17    where
18        T: Hash + Eq,
19    {
20        pub(crate) fn new() -> Self {
21            OrderedSet {
22                set: UnorderedSet::new(),
23                vec: Vec::new(),
24            }
25        }
26
27        pub(crate) fn insert(&mut self, value: &'a T) -> bool {
28            let new = self.set.insert(value);
29            if new {
30                self.vec.push(value);
31            }
32            new
33        }
34    }
35
36    impl<'a, T> OrderedSet<&'a T> {
37        pub(crate) fn is_empty(&self) -> bool {
38            self.vec.is_empty()
39        }
40
41        pub(crate) fn iter(&self) -> Iter<'_, 'a, T> {
42            Iter(self.vec.iter())
43        }
44    }
45
46    impl<'s, 'a, T> IntoIterator for &'s OrderedSet<&'a T> {
47        type Item = &'a T;
48        type IntoIter = Iter<'s, 'a, T>;
49        fn into_iter(self) -> Self::IntoIter {
50            self.iter()
51        }
52    }
53
54    impl<'a, T> IntoIterator for OrderedSet<&'a T> {
55        type Item = &'a T;
56        type IntoIter = <Vec<&'a T> as IntoIterator>::IntoIter;
57        fn into_iter(self) -> Self::IntoIter {
58            self.vec.into_iter()
59        }
60    }
61}
62
63mod unordered {
64    use std::borrow::Borrow;
65    use std::collections::HashSet;
66    use std::hash::Hash;
67
68    // Wrapper prohibits accidentally introducing iteration over the set, which
69    // could lead to nondeterministic generated code.
70    pub(crate) struct UnorderedSet<T>(HashSet<T>);
71
72    impl<T> UnorderedSet<T>
73    where
74        T: Hash + Eq,
75    {
76        pub(crate) fn new() -> Self {
77            UnorderedSet(HashSet::new())
78        }
79
80        pub(crate) fn insert(&mut self, value: T) -> bool {
81            self.0.insert(value)
82        }
83
84        pub(crate) fn contains<Q>(&self, value: &Q) -> bool
85        where
86            T: Borrow<Q>,
87            Q: ?Sized + Hash + Eq,
88        {
89            self.0.contains(value)
90        }
91
92        #[allow(dead_code)] // only used by cxx-build, not cxxbridge-cmd
93        pub(crate) fn get<Q>(&self, value: &Q) -> Option<&T>
94        where
95            T: Borrow<Q>,
96            Q: ?Sized + Hash + Eq,
97        {
98            self.0.get(value)
99        }
100
101        pub(crate) fn retain(&mut self, f: impl FnMut(&T) -> bool) {
102            self.0.retain(f);
103        }
104    }
105}
106
107pub(crate) struct Iter<'s, 'a, T>(slice::Iter<'s, &'a T>);
108
109impl<'s, 'a, T> Iterator for Iter<'s, 'a, T> {
110    type Item = &'a T;
111
112    fn next(&mut self) -> Option<Self::Item> {
113        self.0.next().copied()
114    }
115
116    fn size_hint(&self) -> (usize, Option<usize>) {
117        self.0.size_hint()
118    }
119}
120
121impl<T> Debug for OrderedSet<&T>
122where
123    T: Debug,
124{
125    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
126        formatter.debug_set().entries(self).finish()
127    }
128}
cxx_build/syntax/set.rs

cxx_build/syntax/
set.rs
