rustdoc/formats/
item_type.rs

1//! Item types.
2
3use std::fmt;
4
5use rustc_hir::def::{CtorOf, DefKind, MacroKinds};
6use rustc_hir::def_id::DefId;
7use rustc_middle::ty::TyCtxt;
8use rustc_span::hygiene::MacroKind;
9use serde::{Deserialize, Deserializer, Serialize, Serializer, de};
10
11use crate::clean;
12
13macro_rules! item_type {
14    ($($variant:ident = $number:literal,)+) => {
15
16/// Item type. Corresponds to `clean::ItemEnum` variants.
17///
18/// The search index uses item types encoded as smaller numbers which equal to
19/// discriminants. JavaScript then is used to decode them into the original value.
20/// Consequently, every change to this type should be synchronized to
21/// the `itemTypes` mapping table in `html/static/js/search.js`.
22///
23/// The search engine in search.js also uses item type numbers as a tie breaker when
24/// sorting results. Keywords and primitives are given first because we want them to be easily
25/// found by new users who don't know about advanced features like type filters. The rest are
26/// mostly in an arbitrary order, but it's easier to test the search engine when
27/// it's deterministic, and these are strictly finer-grained than language namespaces, so
28/// using the path and the item type together to sort ensures that search sorting is stable.
29///
30/// In addition, code in `html::render` uses this enum to generate CSS classes, page prefixes, and
31/// module headings. If you are adding to this enum and want to ensure that the sidebar also prints
32/// a heading, edit the listing in `html/render.rs`, function `sidebar_module`. This uses an
33/// ordering based on a helper function inside `item_module`, in the same file.
34#[derive(Copy, PartialEq, Eq, Hash, Clone, Debug, PartialOrd, Ord)]
35#[repr(u8)]
36pub(crate) enum ItemType {
37    $($variant = $number,)+
38}
39
40impl Serialize for ItemType {
41    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
42    where
43        S: Serializer,
44    {
45        (*self as u8).serialize(serializer)
46    }
47}
48
49impl<'de> Deserialize<'de> for ItemType {
50    fn deserialize<D>(deserializer: D) -> Result<ItemType, D::Error>
51    where
52        D: Deserializer<'de>,
53    {
54        struct ItemTypeVisitor;
55        impl<'de> de::Visitor<'de> for ItemTypeVisitor {
56            type Value = ItemType;
57            fn expecting(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
58                write!(formatter, "an integer between 0 and 27")
59            }
60            fn visit_u64<E: de::Error>(self, v: u64) -> Result<ItemType, E> {
61                Ok(match v {
62                    $($number => ItemType::$variant,)+
63                    _ => return Err(E::missing_field("unknown number for `ItemType` enum")),
64                })
65            }
66        }
67        deserializer.deserialize_any(ItemTypeVisitor)
68    }
69}
70
71    }
72}
73
74item_type! {
75    Keyword = 0,
76    Primitive = 1,
77    Module = 2,
78    ExternCrate = 3,
79    Import = 4,
80    Struct = 5,
81    Enum = 6,
82    Function = 7,
83    TypeAlias = 8,
84    Static = 9,
85    Trait = 10,
86    Impl = 11,
87    TyMethod = 12,
88    Method = 13,
89    StructField = 14,
90    Variant = 15,
91    Macro = 16,
92    AssocType = 17,
93    Constant = 18,
94    AssocConst = 19,
95    Union = 20,
96    ForeignType = 21,
97    // OpaqueTy used to be here, but it was removed in #127276
98    ProcAttribute = 23,
99    ProcDerive = 24,
100    TraitAlias = 25,
101    // This number is reserved for use in JavaScript
102    // Generic = 26,
103    Attribute = 27,
104    // The two next ones represent an attr/derive macro declared as a `macro_rules!`. We need this
105    // distinction because they will point to a `macro.[name].html` file and not
106    // `[attr|derive].[name].html` file, so the link generation needs to take it into account while
107    // still having the filtering working as expected.
108    DeclMacroAttribute = 28,
109    DeclMacroDerive = 29,
110}
111
112impl<'a> From<&'a clean::Item> for ItemType {
113    fn from(item: &'a clean::Item) -> ItemType {
114        let kind = match &item.kind {
115            clean::StrippedItem(item) => item,
116            kind => kind,
117        };
118
119        match kind {
120            clean::ModuleItem(..) => ItemType::Module,
121            clean::ExternCrateItem { .. } => ItemType::ExternCrate,
122            clean::ImportItem(..) => ItemType::Import,
123            clean::StructItem(..) => ItemType::Struct,
124            clean::UnionItem(..) => ItemType::Union,
125            clean::EnumItem(..) => ItemType::Enum,
126            clean::FunctionItem(..) => ItemType::Function,
127            clean::TypeAliasItem(..) => ItemType::TypeAlias,
128            clean::StaticItem(..) => ItemType::Static,
129            clean::ConstantItem(..) => ItemType::Constant,
130            clean::TraitItem(..) => ItemType::Trait,
131            clean::ImplItem(..) | clean::PlaceholderImplItem => ItemType::Impl,
132            clean::RequiredMethodItem(..) => ItemType::TyMethod,
133            clean::MethodItem(..) => ItemType::Method,
134            clean::StructFieldItem(..) => ItemType::StructField,
135            clean::VariantItem(..) => ItemType::Variant,
136            clean::ForeignFunctionItem(..) => ItemType::Function, // no ForeignFunction
137            clean::ForeignStaticItem(..) => ItemType::Static,     // no ForeignStatic
138            clean::MacroItem(..) => ItemType::Macro,
139            clean::PrimitiveItem(..) => ItemType::Primitive,
140            clean::RequiredAssocConstItem(..)
141            | clean::ProvidedAssocConstItem(..)
142            | clean::ImplAssocConstItem(..) => ItemType::AssocConst,
143            clean::RequiredAssocTypeItem(..) | clean::AssocTypeItem(..) => ItemType::AssocType,
144            clean::ForeignTypeItem => ItemType::ForeignType,
145            clean::KeywordItem => ItemType::Keyword,
146            clean::AttributeItem => ItemType::Attribute,
147            clean::TraitAliasItem(..) => ItemType::TraitAlias,
148            clean::ProcMacroItem(mac) => match mac.kind {
149                MacroKind::Bang => ItemType::Macro,
150                MacroKind::Attr => ItemType::ProcAttribute,
151                MacroKind::Derive => ItemType::ProcDerive,
152            },
153            clean::StrippedItem(..) => unreachable!(),
154        }
155    }
156}
157
158impl ItemType {
159    pub(crate) fn from_def_id(def_id: DefId, tcx: TyCtxt<'_>) -> Self {
160        let def_kind = tcx.def_kind(def_id);
161        match def_kind {
162            DefKind::Enum => Self::Enum,
163            DefKind::Fn => Self::Function,
164            DefKind::Mod => Self::Module,
165            DefKind::Const { .. } => Self::Constant,
166            DefKind::Static { .. } => Self::Static,
167            DefKind::Struct => Self::Struct,
168            DefKind::Union => Self::Union,
169            DefKind::Trait => Self::Trait,
170            DefKind::TyAlias => Self::TypeAlias,
171            DefKind::TraitAlias => Self::TraitAlias,
172            DefKind::Macro(MacroKinds::ATTR) => ItemType::ProcAttribute,
173            DefKind::Macro(MacroKinds::DERIVE) => ItemType::ProcDerive,
174            DefKind::Macro(_) => ItemType::Macro,
175            DefKind::ForeignTy => Self::ForeignType,
176            DefKind::Variant => Self::Variant,
177            DefKind::Field => Self::StructField,
178            DefKind::AssocTy => Self::AssocType,
179            DefKind::AssocFn => {
180                if tcx.associated_item(def_id).defaultness(tcx).has_value() {
181                    Self::Method
182                } else {
183                    Self::TyMethod
184                }
185            }
186            DefKind::Ctor(CtorOf::Struct, _) => Self::Struct,
187            DefKind::Ctor(CtorOf::Variant, _) => Self::Variant,
188            DefKind::AssocConst { .. } => Self::AssocConst,
189            DefKind::TyParam
190            | DefKind::ConstParam
191            | DefKind::ExternCrate
192            | DefKind::Use
193            | DefKind::ForeignMod
194            | DefKind::AnonConst
195            | DefKind::InlineConst
196            | DefKind::OpaqueTy
197            | DefKind::LifetimeParam
198            | DefKind::GlobalAsm
199            | DefKind::Impl { .. }
200            | DefKind::Closure
201            | DefKind::SyntheticCoroutineBody => Self::ForeignType,
202        }
203    }
204
205    pub(crate) fn as_str(&self) -> &'static str {
206        match self {
207            ItemType::Module => "mod",
208            ItemType::ExternCrate => "externcrate",
209            ItemType::Import => "import",
210            ItemType::Struct => "struct",
211            ItemType::Union => "union",
212            ItemType::Enum => "enum",
213            ItemType::Function => "fn",
214            ItemType::TypeAlias => "type",
215            ItemType::Static => "static",
216            ItemType::Trait => "trait",
217            ItemType::Impl => "impl",
218            ItemType::TyMethod => "tymethod",
219            ItemType::Method => "method",
220            ItemType::StructField => "structfield",
221            ItemType::Variant => "variant",
222            ItemType::Macro => "macro",
223            ItemType::Primitive => "primitive",
224            ItemType::AssocType => "associatedtype",
225            ItemType::Constant => "constant",
226            ItemType::AssocConst => "associatedconstant",
227            ItemType::ForeignType => "foreigntype",
228            ItemType::Keyword => "keyword",
229            ItemType::ProcAttribute | ItemType::DeclMacroAttribute => "attr",
230            ItemType::ProcDerive | ItemType::DeclMacroDerive => "derive",
231            ItemType::TraitAlias => "traitalias",
232            ItemType::Attribute => "attribute",
233        }
234    }
235    pub(crate) fn is_method(&self) -> bool {
236        matches!(self, ItemType::Method | ItemType::TyMethod)
237    }
238    pub(crate) fn is_adt(&self) -> bool {
239        matches!(self, ItemType::Struct | ItemType::Union | ItemType::Enum)
240    }
241    /// Keep this the same as isFnLikeTy in search.js
242    pub(crate) fn is_fn_like(&self) -> bool {
243        matches!(self, ItemType::Function | ItemType::Method | ItemType::TyMethod)
244    }
245}
246
247impl fmt::Display for ItemType {
248    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
249        f.write_str(self.as_str())
250    }
251}
rustdoc/formats/item_type.rs

rustdoc/formats/
item_type.rs
