cxx_gen/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
55mod unordered {
56    use std::borrow::Borrow;
57    use std::collections::HashSet;
58    use std::hash::Hash;
59
60    // Wrapper prohibits accidentally introducing iteration over the set, which
61    // could lead to nondeterministic generated code.
62    pub(crate) struct UnorderedSet<T>(HashSet<T>);
63
64    impl<T> UnorderedSet<T>
65    where
66        T: Hash + Eq,
67    {
68        pub(crate) fn new() -> Self {
69            UnorderedSet(HashSet::new())
70        }
71
72        pub(crate) fn insert(&mut self, value: T) -> bool {
73            self.0.insert(value)
74        }
75
76        pub(crate) fn contains<Q>(&self, value: &Q) -> bool
77        where
78            T: Borrow<Q>,
79            Q: ?Sized + Hash + Eq,
80        {
81            self.0.contains(value)
82        }
83
84        #[allow(dead_code)] // only used by cxx-build, not cxxbridge-cmd
85        pub(crate) fn get<Q>(&self, value: &Q) -> Option<&T>
86        where
87            T: Borrow<Q>,
88            Q: ?Sized + Hash + Eq,
89        {
90            self.0.get(value)
91        }
92
93        pub(crate) fn retain(&mut self, f: impl FnMut(&T) -> bool) {
94            self.0.retain(f);
95        }
96    }
97}
98
99pub(crate) struct Iter<'s, 'a, T>(slice::Iter<'s, &'a T>);
100
101impl<'s, 'a, T> Iterator for Iter<'s, 'a, T> {
102    type Item = &'a T;
103
104    fn next(&mut self) -> Option<Self::Item> {
105        self.0.next().copied()
106    }
107
108    fn size_hint(&self) -> (usize, Option<usize>) {
109        self.0.size_hint()
110    }
111}
112
113impl<T> Debug for OrderedSet<&T>
114where
115    T: Debug,
116{
117    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
118        formatter.debug_set().entries(self).finish()
119    }
120}
cxx_gen/syntax/set.rs

cxx_gen/syntax/
set.rs
