| //! A lowering for `use`-paths (more generally, paths without angle-bracketed segments). |
| |
| use std::{ |
| fmt::{self, Display as _}, |
| iter, |
| }; |
| |
| use crate::{ |
| db::ExpandDatabase, |
| hygiene::Hygiene, |
| name::{known, Name}, |
| }; |
| use base_db::CrateId; |
| use either::Either; |
| use smallvec::SmallVec; |
| use syntax::{ast, AstNode}; |
| |
| #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)] |
| pub struct ModPath { |
| pub kind: PathKind, |
| segments: SmallVec<[Name; 1]>, |
| } |
| |
| #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)] |
| pub struct UnescapedModPath<'a>(&'a ModPath); |
| |
| impl<'a> UnescapedModPath<'a> { |
| pub fn display(&'a self, db: &'a dyn crate::db::ExpandDatabase) -> impl fmt::Display + 'a { |
| UnescapedDisplay { db, path: self } |
| } |
| } |
| |
| #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)] |
| pub enum PathKind { |
| Plain, |
| /// `self::` is `Super(0)` |
| Super(u8), |
| Crate, |
| /// Absolute path (::foo) |
| Abs, |
| /// `$crate` from macro expansion |
| DollarCrate(CrateId), |
| } |
| |
| impl ModPath { |
| pub fn from_src( |
| db: &dyn ExpandDatabase, |
| path: ast::Path, |
| hygiene: &Hygiene, |
| ) -> Option<ModPath> { |
| convert_path(db, None, path, hygiene) |
| } |
| |
| pub fn from_segments(kind: PathKind, segments: impl IntoIterator<Item = Name>) -> ModPath { |
| let segments = segments.into_iter().collect(); |
| ModPath { kind, segments } |
| } |
| |
| /// Creates a `ModPath` from a `PathKind`, with no extra path segments. |
| pub const fn from_kind(kind: PathKind) -> ModPath { |
| ModPath { kind, segments: SmallVec::new_const() } |
| } |
| |
| pub fn segments(&self) -> &[Name] { |
| &self.segments |
| } |
| |
| pub fn push_segment(&mut self, segment: Name) { |
| self.segments.push(segment); |
| } |
| |
| pub fn pop_segment(&mut self) -> Option<Name> { |
| self.segments.pop() |
| } |
| |
| /// Returns the number of segments in the path (counting special segments like `$crate` and |
| /// `super`). |
| pub fn len(&self) -> usize { |
| self.segments.len() |
| + match self.kind { |
| PathKind::Plain => 0, |
| PathKind::Super(i) => i as usize, |
| PathKind::Crate => 1, |
| PathKind::Abs => 0, |
| PathKind::DollarCrate(_) => 1, |
| } |
| } |
| |
| pub fn is_ident(&self) -> bool { |
| self.as_ident().is_some() |
| } |
| |
| pub fn is_self(&self) -> bool { |
| self.kind == PathKind::Super(0) && self.segments.is_empty() |
| } |
| |
| #[allow(non_snake_case)] |
| pub fn is_Self(&self) -> bool { |
| self.kind == PathKind::Plain |
| && matches!(&*self.segments, [name] if *name == known::SELF_TYPE) |
| } |
| |
| /// If this path is a single identifier, like `foo`, return its name. |
| pub fn as_ident(&self) -> Option<&Name> { |
| if self.kind != PathKind::Plain { |
| return None; |
| } |
| |
| match &*self.segments { |
| [name] => Some(name), |
| _ => None, |
| } |
| } |
| |
| pub fn unescaped(&self) -> UnescapedModPath<'_> { |
| UnescapedModPath(self) |
| } |
| |
| pub fn display<'a>(&'a self, db: &'a dyn crate::db::ExpandDatabase) -> impl fmt::Display + 'a { |
| Display { db, path: self } |
| } |
| } |
| |
| struct Display<'a> { |
| db: &'a dyn ExpandDatabase, |
| path: &'a ModPath, |
| } |
| |
| impl fmt::Display for Display<'_> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| display_fmt_path(self.db, self.path, f, true) |
| } |
| } |
| |
| struct UnescapedDisplay<'a> { |
| db: &'a dyn ExpandDatabase, |
| path: &'a UnescapedModPath<'a>, |
| } |
| |
| impl fmt::Display for UnescapedDisplay<'_> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| display_fmt_path(self.db, self.path.0, f, false) |
| } |
| } |
| |
| impl From<Name> for ModPath { |
| fn from(name: Name) -> ModPath { |
| ModPath::from_segments(PathKind::Plain, iter::once(name)) |
| } |
| } |
| fn display_fmt_path( |
| db: &dyn ExpandDatabase, |
| path: &ModPath, |
| f: &mut fmt::Formatter<'_>, |
| escaped: bool, |
| ) -> fmt::Result { |
| let mut first_segment = true; |
| let mut add_segment = |s| -> fmt::Result { |
| if !first_segment { |
| f.write_str("::")?; |
| } |
| first_segment = false; |
| f.write_str(s)?; |
| Ok(()) |
| }; |
| match path.kind { |
| PathKind::Plain => {} |
| PathKind::Super(0) => add_segment("self")?, |
| PathKind::Super(n) => { |
| for _ in 0..n { |
| add_segment("super")?; |
| } |
| } |
| PathKind::Crate => add_segment("crate")?, |
| PathKind::Abs => add_segment("")?, |
| PathKind::DollarCrate(_) => add_segment("$crate")?, |
| } |
| for segment in &path.segments { |
| if !first_segment { |
| f.write_str("::")?; |
| } |
| first_segment = false; |
| if escaped { |
| segment.display(db).fmt(f)?; |
| } else { |
| segment.unescaped().display(db).fmt(f)?; |
| } |
| } |
| Ok(()) |
| } |
| |
| fn convert_path( |
| db: &dyn ExpandDatabase, |
| prefix: Option<ModPath>, |
| path: ast::Path, |
| hygiene: &Hygiene, |
| ) -> Option<ModPath> { |
| let prefix = match path.qualifier() { |
| Some(qual) => Some(convert_path(db, prefix, qual, hygiene)?), |
| None => prefix, |
| }; |
| |
| let segment = path.segment()?; |
| let mut mod_path = match segment.kind()? { |
| ast::PathSegmentKind::Name(name_ref) => { |
| match hygiene.name_ref_to_name(db, name_ref) { |
| Either::Left(name) => { |
| // no type args in use |
| let mut res = prefix.unwrap_or_else(|| { |
| ModPath::from_kind( |
| segment.coloncolon_token().map_or(PathKind::Plain, |_| PathKind::Abs), |
| ) |
| }); |
| res.segments.push(name); |
| res |
| } |
| Either::Right(crate_id) => { |
| return Some(ModPath::from_segments( |
| PathKind::DollarCrate(crate_id), |
| iter::empty(), |
| )) |
| } |
| } |
| } |
| ast::PathSegmentKind::SelfTypeKw => { |
| if prefix.is_some() { |
| return None; |
| } |
| ModPath::from_segments(PathKind::Plain, Some(known::SELF_TYPE)) |
| } |
| ast::PathSegmentKind::CrateKw => { |
| if prefix.is_some() { |
| return None; |
| } |
| ModPath::from_segments(PathKind::Crate, iter::empty()) |
| } |
| ast::PathSegmentKind::SelfKw => { |
| if prefix.is_some() { |
| return None; |
| } |
| ModPath::from_segments(PathKind::Super(0), iter::empty()) |
| } |
| ast::PathSegmentKind::SuperKw => { |
| let nested_super_count = match prefix.map(|p| p.kind) { |
| Some(PathKind::Super(n)) => n, |
| Some(_) => return None, |
| None => 0, |
| }; |
| |
| ModPath::from_segments(PathKind::Super(nested_super_count + 1), iter::empty()) |
| } |
| ast::PathSegmentKind::Type { .. } => { |
| // not allowed in imports |
| return None; |
| } |
| }; |
| |
| // handle local_inner_macros : |
| // Basically, even in rustc it is quite hacky: |
| // https://github.com/rust-lang/rust/blob/614f273e9388ddd7804d5cbc80b8865068a3744e/src/librustc_resolve/macros.rs#L456 |
| // We follow what it did anyway :) |
| if mod_path.segments.len() == 1 && mod_path.kind == PathKind::Plain { |
| if let Some(_macro_call) = path.syntax().parent().and_then(ast::MacroCall::cast) { |
| if let Some(crate_id) = hygiene.local_inner_macros(db, path) { |
| mod_path.kind = PathKind::DollarCrate(crate_id); |
| } |
| } |
| } |
| |
| Some(mod_path) |
| } |
| |
| pub use crate::name as __name; |
| |
| #[macro_export] |
| macro_rules! __known_path { |
| (core::iter::IntoIterator) => {}; |
| (core::iter::Iterator) => {}; |
| (core::result::Result) => {}; |
| (core::option::Option) => {}; |
| (core::ops::Range) => {}; |
| (core::ops::RangeFrom) => {}; |
| (core::ops::RangeFull) => {}; |
| (core::ops::RangeTo) => {}; |
| (core::ops::RangeToInclusive) => {}; |
| (core::ops::RangeInclusive) => {}; |
| (core::future::Future) => {}; |
| (core::future::IntoFuture) => {}; |
| (core::ops::Try) => {}; |
| ($path:path) => { |
| compile_error!("Please register your known path in the path module") |
| }; |
| } |
| |
| #[macro_export] |
| macro_rules! __path { |
| ($start:ident $(:: $seg:ident)*) => ({ |
| $crate::__known_path!($start $(:: $seg)*); |
| $crate::mod_path::ModPath::from_segments($crate::mod_path::PathKind::Abs, vec![ |
| $crate::mod_path::__name![$start], $($crate::mod_path::__name![$seg],)* |
| ]) |
| }); |
| } |
| |
| pub use crate::__path as path; |