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remove unused return types such as empty Results or Options that would always be...
[rust.git] / src / librustdoc / fold.rs
1 use crate::clean::*;
2
3 crate struct StripItem(pub Item);
4
5 impl StripItem {
6     crate fn strip(self) -> Item {
7         match self.0 {
8             Item { kind: box StrippedItem(..), .. } => self.0,
9             mut i => {
10                 i.kind = box StrippedItem(i.kind);
11                 i
12             }
13         }
14     }
15 }
16
17 crate trait DocFolder: Sized {
18     fn fold_item(&mut self, item: Item) -> Option<Item> {
19         Some(self.fold_item_recur(item))
20     }
21
22     /// don't override!
23     fn fold_inner_recur(&mut self, kind: ItemKind) -> ItemKind {
24         match kind {
25             StrippedItem(..) => unreachable!(),
26             ModuleItem(i) => ModuleItem(self.fold_mod(i)),
27             StructItem(mut i) => {
28                 let num_fields = i.fields.len();
29                 i.fields = i.fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
30                 i.fields_stripped |=
31                     num_fields != i.fields.len() || i.fields.iter().any(|f| f.is_stripped());
32                 StructItem(i)
33             }
34             UnionItem(mut i) => {
35                 let num_fields = i.fields.len();
36                 i.fields = i.fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
37                 i.fields_stripped |=
38                     num_fields != i.fields.len() || i.fields.iter().any(|f| f.is_stripped());
39                 UnionItem(i)
40             }
41             EnumItem(mut i) => {
42                 let num_variants = i.variants.len();
43                 i.variants = i.variants.into_iter().filter_map(|x| self.fold_item(x)).collect();
44                 i.variants_stripped |=
45                     num_variants != i.variants.len() || i.variants.iter().any(|f| f.is_stripped());
46                 EnumItem(i)
47             }
48             TraitItem(mut i) => {
49                 i.items = i.items.into_iter().filter_map(|x| self.fold_item(x)).collect();
50                 TraitItem(i)
51             }
52             ImplItem(mut i) => {
53                 i.items = i.items.into_iter().filter_map(|x| self.fold_item(x)).collect();
54                 ImplItem(i)
55             }
56             VariantItem(i) => {
57                 let i2 = i.clone(); // this clone is small
58                 match i.kind {
59                     VariantKind::Struct(mut j) => {
60                         let num_fields = j.fields.len();
61                         j.fields = j.fields.into_iter().filter_map(|x| self.fold_item(x)).collect();
62                         j.fields_stripped |= num_fields != j.fields.len()
63                             || j.fields.iter().any(|f| f.is_stripped());
64                         VariantItem(Variant { kind: VariantKind::Struct(j), ..i2 })
65                     }
66                     _ => VariantItem(i2),
67                 }
68             }
69             x => x,
70         }
71     }
72
73     /// don't override!
74     fn fold_item_recur(&mut self, mut item: Item) -> Item {
75         item.kind = box match *item.kind {
76             StrippedItem(box i) => StrippedItem(box self.fold_inner_recur(i)),
77             _ => self.fold_inner_recur(*item.kind),
78         };
79         item
80     }
81
82     fn fold_mod(&mut self, m: Module) -> Module {
83         Module {
84             is_crate: m.is_crate,
85             items: m.items.into_iter().filter_map(|i| self.fold_item(i)).collect(),
86         }
87     }
88
89     fn fold_crate(&mut self, mut c: Crate) -> Crate {
90         c.module = c.module.take().and_then(|module| self.fold_item(module));
91
92         {
93             let external_traits = { std::mem::take(&mut *c.external_traits.borrow_mut()) };
94             for (k, mut v) in external_traits {
95                 v.items = v.items.into_iter().filter_map(|i| self.fold_item(i)).collect();
96                 c.external_traits.borrow_mut().insert(k, v);
97             }
98         }
99         c
100     }
101 }