rust/crates/ide_db/src/helpers.rs

285 lines
10 KiB
Rust

//! A module with ide helpers for high-level ide features.
pub mod famous_defs;
pub mod generated_lints;
pub mod import_assets;
pub mod insert_use;
pub mod merge_imports;
pub mod node_ext;
pub mod rust_doc;
use std::{collections::VecDeque, iter};
use base_db::FileId;
use hir::{ItemInNs, MacroDef, ModuleDef, Name, PathResolution, Semantics};
use itertools::Itertools;
use syntax::{
ast::{self, make, HasLoopBody, Ident},
AstNode, AstToken, Direction, SyntaxElement, SyntaxKind, SyntaxToken, TokenAtOffset, WalkEvent,
T,
};
use crate::{defs::Definition, RootDatabase};
pub use self::famous_defs::FamousDefs;
pub fn item_name(db: &RootDatabase, item: ItemInNs) -> Option<Name> {
match item {
ItemInNs::Types(module_def_id) => ModuleDef::from(module_def_id).name(db),
ItemInNs::Values(module_def_id) => ModuleDef::from(module_def_id).name(db),
ItemInNs::Macros(macro_def_id) => MacroDef::from(macro_def_id).name(db),
}
}
/// Parses and returns the derive path at the cursor position in the given attribute, if it is a derive.
/// This special case is required because the derive macro is a compiler builtin that discards the input derives.
///
/// The returned path is synthesized from TokenTree tokens and as such cannot be used with the [`Semantics`].
pub fn get_path_in_derive_attr(
sema: &hir::Semantics<RootDatabase>,
attr: &ast::Attr,
cursor: &Ident,
) -> Option<ast::Path> {
let cursor = cursor.syntax();
let path = attr.path()?;
let tt = attr.token_tree()?;
if !tt.syntax().text_range().contains_range(cursor.text_range()) {
return None;
}
let scope = sema.scope(attr.syntax());
let resolved_attr = sema.resolve_path(&path)?;
let derive = FamousDefs(sema, scope.krate()).core_macros_builtin_derive()?;
if PathResolution::Macro(derive) != resolved_attr {
return None;
}
let first = cursor
.siblings_with_tokens(Direction::Prev)
.filter_map(SyntaxElement::into_token)
.take_while(|tok| tok.kind() != T!['('] && tok.kind() != T![,])
.last()?;
let path_tokens = first
.siblings_with_tokens(Direction::Next)
.filter_map(SyntaxElement::into_token)
.take_while(|tok| tok != cursor);
ast::Path::parse(&path_tokens.chain(iter::once(cursor.clone())).join("")).ok()
}
/// Parses and resolves the path at the cursor position in the given attribute, if it is a derive.
/// This special case is required because the derive macro is a compiler builtin that discards the input derives.
pub fn try_resolve_derive_input(
sema: &hir::Semantics<RootDatabase>,
attr: &ast::Attr,
cursor: &Ident,
) -> Option<PathResolution> {
let path = get_path_in_derive_attr(sema, attr, cursor)?;
let scope = sema.scope(attr.syntax());
// FIXME: This double resolve shouldn't be necessary
// It's only here so we prefer macros over other namespaces
match scope.speculative_resolve_as_mac(&path) {
Some(mac) if mac.kind() == hir::MacroKind::Derive => Some(PathResolution::Macro(mac)),
Some(_) => return None,
None => scope
.speculative_resolve(&path)
.filter(|res| matches!(res, PathResolution::Def(ModuleDef::Module(_)))),
}
}
/// Picks the token with the highest rank returned by the passed in function.
pub fn pick_best_token(
tokens: TokenAtOffset<SyntaxToken>,
f: impl Fn(SyntaxKind) -> usize,
) -> Option<SyntaxToken> {
tokens.max_by_key(move |t| f(t.kind()))
}
/// Converts the mod path struct into its ast representation.
pub fn mod_path_to_ast(path: &hir::ModPath) -> ast::Path {
let _p = profile::span("mod_path_to_ast");
let mut segments = Vec::new();
let mut is_abs = false;
match path.kind {
hir::PathKind::Plain => {}
hir::PathKind::Super(0) => segments.push(make::path_segment_self()),
hir::PathKind::Super(n) => segments.extend((0..n).map(|_| make::path_segment_super())),
hir::PathKind::DollarCrate(_) | hir::PathKind::Crate => {
segments.push(make::path_segment_crate())
}
hir::PathKind::Abs => is_abs = true,
}
segments.extend(
path.segments()
.iter()
.map(|segment| make::path_segment(make::name_ref(&segment.to_smol_str()))),
);
make::path_from_segments(segments, is_abs)
}
/// Iterates all `ModuleDef`s and `Impl` blocks of the given file.
pub fn visit_file_defs(
sema: &Semantics<RootDatabase>,
file_id: FileId,
cb: &mut dyn FnMut(Definition),
) {
let db = sema.db;
let module = match sema.to_module_def(file_id) {
Some(it) => it,
None => return,
};
let mut defs: VecDeque<_> = module.declarations(db).into();
while let Some(def) = defs.pop_front() {
if let ModuleDef::Module(submodule) = def {
if let hir::ModuleSource::Module(_) = submodule.definition_source(db).value {
defs.extend(submodule.declarations(db));
submodule.impl_defs(db).into_iter().for_each(|impl_| cb(impl_.into()));
}
}
cb(def.into());
}
module.impl_defs(db).into_iter().for_each(|impl_| cb(impl_.into()));
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct SnippetCap {
_private: (),
}
impl SnippetCap {
pub const fn new(allow_snippets: bool) -> Option<SnippetCap> {
if allow_snippets {
Some(SnippetCap { _private: () })
} else {
None
}
}
}
/// Calls `cb` on each expression inside `expr` that is at "tail position".
/// Does not walk into `break` or `return` expressions.
/// Note that modifying the tree while iterating it will cause undefined iteration which might
/// potentially results in an out of bounds panic.
pub fn for_each_tail_expr(expr: &ast::Expr, cb: &mut dyn FnMut(&ast::Expr)) {
match expr {
ast::Expr::BlockExpr(b) => {
match b.modifier() {
Some(
ast::BlockModifier::Async(_)
| ast::BlockModifier::Try(_)
| ast::BlockModifier::Const(_),
) => return cb(expr),
Some(ast::BlockModifier::Label(label)) => {
for_each_break_expr(Some(label), b.stmt_list(), &mut |b| {
cb(&ast::Expr::BreakExpr(b))
});
}
Some(ast::BlockModifier::Unsafe(_)) => (),
None => (),
}
if let Some(stmt_list) = b.stmt_list() {
if let Some(e) = stmt_list.tail_expr() {
for_each_tail_expr(&e, cb);
}
}
}
ast::Expr::IfExpr(if_) => {
let mut if_ = if_.clone();
loop {
if let Some(block) = if_.then_branch() {
for_each_tail_expr(&ast::Expr::BlockExpr(block), cb);
}
match if_.else_branch() {
Some(ast::ElseBranch::IfExpr(it)) => if_ = it,
Some(ast::ElseBranch::Block(block)) => {
for_each_tail_expr(&ast::Expr::BlockExpr(block), cb);
break;
}
None => break,
}
}
}
ast::Expr::LoopExpr(l) => {
for_each_break_expr(l.label(), l.loop_body().and_then(|it| it.stmt_list()), &mut |b| {
cb(&ast::Expr::BreakExpr(b))
})
}
ast::Expr::MatchExpr(m) => {
if let Some(arms) = m.match_arm_list() {
arms.arms().filter_map(|arm| arm.expr()).for_each(|e| for_each_tail_expr(&e, cb));
}
}
ast::Expr::ArrayExpr(_)
| ast::Expr::AwaitExpr(_)
| ast::Expr::BinExpr(_)
| ast::Expr::BoxExpr(_)
| ast::Expr::BreakExpr(_)
| ast::Expr::CallExpr(_)
| ast::Expr::CastExpr(_)
| ast::Expr::ClosureExpr(_)
| ast::Expr::ContinueExpr(_)
| ast::Expr::FieldExpr(_)
| ast::Expr::ForExpr(_)
| ast::Expr::IndexExpr(_)
| ast::Expr::Literal(_)
| ast::Expr::MacroCall(_)
| ast::Expr::MacroStmts(_)
| ast::Expr::MethodCallExpr(_)
| ast::Expr::ParenExpr(_)
| ast::Expr::PathExpr(_)
| ast::Expr::PrefixExpr(_)
| ast::Expr::RangeExpr(_)
| ast::Expr::RecordExpr(_)
| ast::Expr::RefExpr(_)
| ast::Expr::ReturnExpr(_)
| ast::Expr::TryExpr(_)
| ast::Expr::TupleExpr(_)
| ast::Expr::WhileExpr(_)
| ast::Expr::YieldExpr(_) => cb(expr),
}
}
/// Calls `cb` on each break expr inside of `body` that is applicable for the given label.
pub fn for_each_break_expr(
label: Option<ast::Label>,
body: Option<ast::StmtList>,
cb: &mut dyn FnMut(ast::BreakExpr),
) {
let label = label.and_then(|lbl| lbl.lifetime());
let mut depth = 0;
if let Some(b) = body {
let preorder = &mut b.syntax().preorder();
let ev_as_expr = |ev| match ev {
WalkEvent::Enter(it) => Some(WalkEvent::Enter(ast::Expr::cast(it)?)),
WalkEvent::Leave(it) => Some(WalkEvent::Leave(ast::Expr::cast(it)?)),
};
let eq_label = |lt: Option<ast::Lifetime>| {
lt.zip(label.as_ref()).map_or(false, |(lt, lbl)| lt.text() == lbl.text())
};
while let Some(node) = preorder.find_map(ev_as_expr) {
match node {
WalkEvent::Enter(expr) => match expr {
ast::Expr::LoopExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::ForExpr(_) => {
depth += 1
}
ast::Expr::BlockExpr(e) if e.label().is_some() => depth += 1,
ast::Expr::BreakExpr(b)
if (depth == 0 && b.lifetime().is_none()) || eq_label(b.lifetime()) =>
{
cb(b);
}
_ => (),
},
WalkEvent::Leave(expr) => match expr {
ast::Expr::LoopExpr(_) | ast::Expr::WhileExpr(_) | ast::Expr::ForExpr(_) => {
depth -= 1
}
ast::Expr::BlockExpr(e) if e.label().is_some() => depth -= 1,
_ => (),
},
}
}
}
}