aboutsummaryrefslogtreecommitdiff
path: root/crates/ra_ide/src/display/function_signature.rs
blob: 324ad95526d655c51c467ceae58ae97faa2dfefc (plain)
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
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
//! FIXME: write short doc here

use std::fmt::{self, Display};

use hir::{Docs, Documentation, HasSource, HirDisplay};
use join_to_string::join;
use ra_syntax::ast::{self, AstNode, NameOwner, VisibilityOwner};
use std::convert::From;

use crate::{
    db,
    display::{generic_parameters, where_predicates},
};

#[derive(Debug)]
pub enum CallableKind {
    Function,
    StructConstructor,
    VariantConstructor,
    Macro,
}

/// Contains information about a function signature
#[derive(Debug)]
pub struct FunctionSignature {
    pub kind: CallableKind,
    /// Optional visibility
    pub visibility: Option<String>,
    /// Name of the function
    pub name: Option<String>,
    /// Documentation for the function
    pub doc: Option<Documentation>,
    /// Generic parameters
    pub generic_parameters: Vec<String>,
    /// Parameters of the function
    pub parameters: Vec<String>,
    /// Optional return type
    pub ret_type: Option<String>,
    /// Where predicates
    pub where_predicates: Vec<String>,
}

impl FunctionSignature {
    pub(crate) fn with_doc_opt(mut self, doc: Option<Documentation>) -> Self {
        self.doc = doc;
        self
    }

    pub(crate) fn from_hir(db: &db::RootDatabase, function: hir::Function) -> Self {
        let doc = function.docs(db);
        let ast_node = function.source(db).value;
        FunctionSignature::from(&ast_node).with_doc_opt(doc)
    }

    pub(crate) fn from_struct(db: &db::RootDatabase, st: hir::Struct) -> Option<Self> {
        let node: ast::StructDef = st.source(db).value;
        match node.kind() {
            ast::StructKind::Record(_) => return None,
            _ => (),
        };

        let params = st
            .fields(db)
            .into_iter()
            .map(|field: hir::StructField| {
                let ty = field.ty(db);
                format!("{}", ty.display(db))
            })
            .collect();

        Some(
            FunctionSignature {
                kind: CallableKind::StructConstructor,
                visibility: node.visibility().map(|n| n.syntax().text().to_string()),
                name: node.name().map(|n| n.text().to_string()),
                ret_type: node.name().map(|n| n.text().to_string()),
                parameters: params,
                generic_parameters: generic_parameters(&node),
                where_predicates: where_predicates(&node),
                doc: None,
            }
            .with_doc_opt(st.docs(db)),
        )
    }

    pub(crate) fn from_enum_variant(
        db: &db::RootDatabase,
        variant: hir::EnumVariant,
    ) -> Option<Self> {
        let node: ast::EnumVariant = variant.source(db).value;
        match node.kind() {
            ast::StructKind::Record(_) | ast::StructKind::Unit => return None,
            _ => (),
        };

        let parent_name = variant.parent_enum(db).name(db).to_string();

        let name = format!("{}::{}", parent_name, variant.name(db));

        let params = variant
            .fields(db)
            .into_iter()
            .map(|field: hir::StructField| {
                let name = field.name(db);
                let ty = field.ty(db);
                format!("{}: {}", name, ty.display(db))
            })
            .collect();

        Some(
            FunctionSignature {
                kind: CallableKind::VariantConstructor,
                visibility: None,
                name: Some(name),
                ret_type: None,
                parameters: params,
                generic_parameters: vec![],
                where_predicates: vec![],
                doc: None,
            }
            .with_doc_opt(variant.docs(db)),
        )
    }

    pub(crate) fn from_macro(db: &db::RootDatabase, macro_def: hir::MacroDef) -> Option<Self> {
        let node: ast::MacroCall = macro_def.source(db).value;

        let params = vec![];

        Some(
            FunctionSignature {
                kind: CallableKind::Macro,
                visibility: None,
                name: node.name().map(|n| n.text().to_string()),
                ret_type: None,
                parameters: params,
                generic_parameters: vec![],
                where_predicates: vec![],
                doc: None,
            }
            .with_doc_opt(macro_def.docs(db)),
        )
    }
}

impl From<&'_ ast::FnDef> for FunctionSignature {
    fn from(node: &ast::FnDef) -> FunctionSignature {
        fn param_list(node: &ast::FnDef) -> Vec<String> {
            let mut res = vec![];
            if let Some(param_list) = node.param_list() {
                if let Some(self_param) = param_list.self_param() {
                    res.push(self_param.syntax().text().to_string())
                }

                res.extend(param_list.params().map(|param| param.syntax().text().to_string()));
            }
            res
        }

        FunctionSignature {
            kind: CallableKind::Function,
            visibility: node.visibility().map(|n| n.syntax().text().to_string()),
            name: node.name().map(|n| n.text().to_string()),
            ret_type: node
                .ret_type()
                .and_then(|r| r.type_ref())
                .map(|n| n.syntax().text().to_string()),
            parameters: param_list(node),
            generic_parameters: generic_parameters(node),
            where_predicates: where_predicates(node),
            // docs are processed separately
            doc: None,
        }
    }
}

impl Display for FunctionSignature {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        if let Some(t) = &self.visibility {
            write!(f, "{} ", t)?;
        }

        if let Some(name) = &self.name {
            match self.kind {
                CallableKind::Function => write!(f, "fn {}", name)?,
                CallableKind::StructConstructor => write!(f, "struct {}", name)?,
                CallableKind::VariantConstructor => write!(f, "{}", name)?,
                CallableKind::Macro => write!(f, "{}!", name)?,
            }
        }

        if !self.generic_parameters.is_empty() {
            join(self.generic_parameters.iter())
                .separator(", ")
                .surround_with("<", ">")
                .to_fmt(f)?;
        }

        join(self.parameters.iter()).separator(", ").surround_with("(", ")").to_fmt(f)?;

        if let Some(t) = &self.ret_type {
            write!(f, " -> {}", t)?;
        }

        if !self.where_predicates.is_empty() {
            write!(f, "\nwhere ")?;
            join(self.where_predicates.iter()).separator(",\n      ").to_fmt(f)?;
        }

        Ok(())
    }
}