1 //! This crate provides primitives for tracking the information about a call site.
2 use base_db::FilePosition;
4 use hir::{HasAttrs, HirDisplay, Semantics, Type};
8 ast::{self, ArgListOwner, NameOwner},
9 match_ast, AstNode, Direction, SyntaxNode, SyntaxToken, TextRange, TextSize,
12 use crate::RootDatabase;
14 /// Contains information about a call site. Specifically the
15 /// `FunctionSignature`and current parameter.
18 pub doc: Option<String>,
19 pub signature: String,
20 pub active_parameter: Option<usize>,
21 parameters: Vec<TextRange>,
25 pub fn parameter_labels(&self) -> impl Iterator<Item = &str> + '_ {
26 self.parameters.iter().map(move |&it| &self.signature[it])
28 pub fn parameter_ranges(&self) -> &[TextRange] {
31 fn push_param(&mut self, param: &str) {
32 if !self.signature.ends_with('(') {
33 self.signature.push_str(", ");
35 let start = TextSize::of(&self.signature);
36 self.signature.push_str(param);
37 let end = TextSize::of(&self.signature);
38 self.parameters.push(TextRange::new(start, end))
42 /// Computes parameter information for the given call expression.
43 pub fn call_info(db: &RootDatabase, position: FilePosition) -> Option<CallInfo> {
44 let sema = Semantics::new(db);
45 let file = sema.parse(position.file_id);
46 let file = file.syntax();
48 .token_at_offset(position.offset)
50 // if the cursor is sandwiched between two space tokens and the call is unclosed
51 // this prevents us from leaving the CallExpression
52 .and_then(|tok| algo::skip_trivia_token(tok, Direction::Prev))?;
53 let token = sema.descend_into_macros(token);
55 let (callable, active_parameter) = call_info_impl(&sema, token)?;
58 CallInfo { doc: None, signature: String::new(), parameters: vec![], active_parameter };
60 match callable.kind() {
61 hir::CallableKind::Function(func) => {
62 res.doc = func.docs(db).map(|it| it.into());
63 format_to!(res.signature, "fn {}", func.name(db));
65 hir::CallableKind::TupleStruct(strukt) => {
66 res.doc = strukt.docs(db).map(|it| it.into());
67 format_to!(res.signature, "struct {}", strukt.name(db));
69 hir::CallableKind::TupleEnumVariant(variant) => {
70 res.doc = variant.docs(db).map(|it| it.into());
74 variant.parent_enum(db).name(db),
78 hir::CallableKind::Closure => (),
81 res.signature.push('(');
83 if let Some(self_param) = callable.receiver_param(db) {
84 format_to!(res.signature, "{}", self_param)
86 let mut buf = String::new();
87 for (pat, ty) in callable.params(db) {
89 if let Some(pat) = pat {
91 Either::Left(_self) => format_to!(buf, "self: "),
92 Either::Right(pat) => format_to!(buf, "{}: ", pat),
95 format_to!(buf, "{}", ty.display(db));
99 res.signature.push(')');
101 match callable.kind() {
102 hir::CallableKind::Function(_) | hir::CallableKind::Closure => {
103 let ret_type = callable.return_type();
104 if !ret_type.is_unit() {
105 format_to!(res.signature, " -> {}", ret_type.display(db));
108 hir::CallableKind::TupleStruct(_) | hir::CallableKind::TupleEnumVariant(_) => {}
114 sema: &Semantics<RootDatabase>,
116 ) -> Option<(hir::Callable, Option<usize>)> {
117 // Find the calling expression and it's NameRef
118 let calling_node = FnCallNode::with_node(&token.parent()?)?;
120 let callable = match &calling_node {
121 FnCallNode::CallExpr(call) => {
122 sema.type_of_expr(&call.expr()?)?.adjusted().as_callable(sema.db)?
124 FnCallNode::MethodCallExpr(call) => sema.resolve_method_call_as_callable(call)?,
126 let active_param = if let Some(arg_list) = calling_node.arg_list() {
127 // Number of arguments specified at the call site
128 let num_args_at_callsite = arg_list.args().count();
130 let arg_list_range = arg_list.syntax().text_range();
131 if !arg_list_range.contains_inclusive(token.text_range().start()) {
132 cov_mark::hit!(call_info_bad_offset);
135 let param = std::cmp::min(
136 num_args_at_callsite,
139 .take_while(|arg| arg.syntax().text_range().end() <= token.text_range().start())
147 Some((callable, active_param))
151 pub struct ActiveParameter {
153 pub pat: Either<ast::SelfParam, ast::Pat>,
156 impl ActiveParameter {
157 pub fn at(db: &RootDatabase, position: FilePosition) -> Option<Self> {
158 let sema = Semantics::new(db);
159 let file = sema.parse(position.file_id);
160 let file = file.syntax();
161 let token = file.token_at_offset(position.offset).next()?;
162 let token = sema.descend_into_macros(token);
163 Self::at_token(&sema, token)
166 pub fn at_token(sema: &Semantics<RootDatabase>, token: SyntaxToken) -> Option<Self> {
167 let (signature, active_parameter) = call_info_impl(sema, token)?;
169 let idx = active_parameter?;
170 let mut params = signature.params(sema.db);
171 if !(idx < params.len()) {
172 cov_mark::hit!(too_many_arguments);
175 let (pat, ty) = params.swap_remove(idx);
176 pat.map(|pat| ActiveParameter { ty, pat })
179 pub fn ident(&self) -> Option<ast::Name> {
180 self.pat.as_ref().right().and_then(|param| match param {
181 ast::Pat::IdentPat(ident) => ident.name(),
188 pub enum FnCallNode {
189 CallExpr(ast::CallExpr),
190 MethodCallExpr(ast::MethodCallExpr),
194 fn with_node(syntax: &SyntaxNode) -> Option<FnCallNode> {
195 syntax.ancestors().find_map(|node| {
198 ast::CallExpr(it) => Some(FnCallNode::CallExpr(it)),
199 ast::MethodCallExpr(it) => {
200 let arg_list = it.arg_list()?;
201 if !arg_list.syntax().text_range().contains_range(syntax.text_range()) {
204 Some(FnCallNode::MethodCallExpr(it))
212 pub fn with_node_exact(node: &SyntaxNode) -> Option<FnCallNode> {
215 ast::CallExpr(it) => Some(FnCallNode::CallExpr(it)),
216 ast::MethodCallExpr(it) => Some(FnCallNode::MethodCallExpr(it)),
222 pub fn name_ref(&self) -> Option<ast::NameRef> {
224 FnCallNode::CallExpr(call_expr) => Some(match call_expr.expr()? {
225 ast::Expr::PathExpr(path_expr) => path_expr.path()?.segment()?.name_ref()?,
228 FnCallNode::MethodCallExpr(call_expr) => {
229 call_expr.syntax().children().find_map(ast::NameRef::cast)
234 fn arg_list(&self) -> Option<ast::ArgList> {
236 FnCallNode::CallExpr(expr) => expr.arg_list(),
237 FnCallNode::MethodCallExpr(expr) => expr.arg_list(),