use std::{iter, sync::Arc}; use ra_syntax::{ ast::{self, NameOwner, TypeAscriptionOwner}, AstNode, }; use crate::{name, type_ref::TypeRef, AsName, Name}; #[derive(Debug, Clone, PartialEq, Eq, Hash)] pub struct Path { pub kind: PathKind, pub segments: Vec, } #[derive(Debug, Clone, PartialEq, Eq, Hash)] pub struct PathSegment { pub name: Name, pub args_and_bindings: Option>, } /// Generic arguments to a path segment (e.g. the `i32` in `Option`). This /// can (in the future) also include bindings of associated types, like in /// `Iterator`. #[derive(Debug, Clone, PartialEq, Eq, Hash)] pub struct GenericArgs { pub args: Vec, /// This specifies whether the args contain a Self type as the first /// element. This is the case for path segments like ``, where /// `T` is actually a type parameter for the path `Trait` specifying the /// Self type. Otherwise, when we have a path `Trait`, the Self type /// is left out. pub has_self_type: bool, /// Associated type bindings like in `Iterator`. pub bindings: Vec<(Name, TypeRef)>, } /// A single generic argument. #[derive(Debug, Clone, PartialEq, Eq, Hash)] pub enum GenericArg { Type(TypeRef), // or lifetime... } #[derive(Debug, Clone, PartialEq, Eq, Hash)] pub enum PathKind { Plain, Self_, Super, Crate, // Absolute path Abs, // Type based path like `::foo` Type(Box), } impl Path { /// Calls `cb` with all paths, represented by this use item. pub fn expand_use_item( item: &ast::UseItem, mut cb: impl FnMut(Path, &ast::UseTree, bool, Option), ) { if let Some(tree) = item.use_tree() { expand_use_tree(None, tree, &mut cb); } } pub fn from_simple_segments(kind: PathKind, segments: impl IntoIterator) -> Path { Path { kind, segments: segments .into_iter() .map(|name| PathSegment { name, args_and_bindings: None }) .collect(), } } /// Converts an `ast::Path` to `Path`. Works with use trees. pub fn from_ast(mut path: ast::Path) -> Option { let mut kind = PathKind::Plain; let mut segments = Vec::new(); loop { let segment = path.segment()?; if segment.has_colon_colon() { kind = PathKind::Abs; } match segment.kind()? { ast::PathSegmentKind::Name(name) => { let args = segment .type_arg_list() .and_then(GenericArgs::from_ast) .or_else(|| { GenericArgs::from_fn_like_path_ast( segment.param_list(), segment.ret_type(), ) }) .map(Arc::new); let segment = PathSegment { name: name.as_name(), args_and_bindings: args }; segments.push(segment); } ast::PathSegmentKind::Type { type_ref, trait_ref } => { assert!(path.qualifier().is_none()); // this can only occur at the first segment let self_type = TypeRef::from_ast(type_ref?); match trait_ref { // ::foo None => { kind = PathKind::Type(Box::new(self_type)); } // >::Foo desugars to Trait::Foo Some(trait_ref) => { let path = Path::from_ast(trait_ref.path()?)?; kind = path.kind; let mut prefix_segments = path.segments; prefix_segments.reverse(); segments.extend(prefix_segments); // Insert the type reference (T in the above example) as Self parameter for the trait let mut last_segment = segments.last_mut()?; if last_segment.args_and_bindings.is_none() { last_segment.args_and_bindings = Some(Arc::new(GenericArgs::empty())); }; let args = last_segment.args_and_bindings.as_mut().unwrap(); let mut args_inner = Arc::make_mut(args); args_inner.has_self_type = true; args_inner.args.insert(0, GenericArg::Type(self_type)); } } } ast::PathSegmentKind::CrateKw => { kind = PathKind::Crate; break; } ast::PathSegmentKind::SelfKw => { kind = PathKind::Self_; break; } ast::PathSegmentKind::SuperKw => { kind = PathKind::Super; break; } } path = match qualifier(&path) { Some(it) => it, None => break, }; } segments.reverse(); return Some(Path { kind, segments }); fn qualifier(path: &ast::Path) -> Option { if let Some(q) = path.qualifier() { return Some(q); } // FIXME: this bottom up traversal is not too precise. // Should we handle do a top-down analysis, recording results? let use_tree_list = path.syntax().ancestors().find_map(ast::UseTreeList::cast)?; let use_tree = use_tree_list.parent_use_tree(); use_tree.path() } } /// Converts an `ast::NameRef` into a single-identifier `Path`. pub fn from_name_ref(name_ref: &ast::NameRef) -> Path { name_ref.as_name().into() } /// `true` is this path is a single identifier, like `foo` pub fn is_ident(&self) -> bool { self.kind == PathKind::Plain && self.segments.len() == 1 } /// `true` if this path is just a standalone `self` pub fn is_self(&self) -> bool { self.kind == PathKind::Self_ && self.segments.is_empty() } /// If this path is a single identifier, like `foo`, return its name. pub fn as_ident(&self) -> Option<&Name> { if self.kind != PathKind::Plain || self.segments.len() > 1 { return None; } self.segments.first().map(|s| &s.name) } pub fn expand_macro_expr(&self) -> Option { self.as_ident().and_then(|name| Some(name.clone())) } } impl GenericArgs { pub(crate) fn from_ast(node: ast::TypeArgList) -> Option { let mut args = Vec::new(); for type_arg in node.type_args() { let type_ref = TypeRef::from_ast_opt(type_arg.type_ref()); args.push(GenericArg::Type(type_ref)); } // lifetimes ignored for now let mut bindings = Vec::new(); for assoc_type_arg in node.assoc_type_args() { if let Some(name_ref) = assoc_type_arg.name_ref() { let name = name_ref.as_name(); let type_ref = TypeRef::from_ast_opt(assoc_type_arg.type_ref()); bindings.push((name, type_ref)); } } if args.is_empty() && bindings.is_empty() { None } else { Some(GenericArgs { args, has_self_type: false, bindings }) } } /// Collect `GenericArgs` from the parts of a fn-like path, i.e. `Fn(X, Y) /// -> Z` (which desugars to `Fn<(X, Y), Output=Z>`). pub(crate) fn from_fn_like_path_ast( params: Option, ret_type: Option, ) -> Option { let mut args = Vec::new(); let mut bindings = Vec::new(); if let Some(params) = params { let mut param_types = Vec::new(); for param in params.params() { let type_ref = TypeRef::from_ast_opt(param.ascribed_type()); param_types.push(type_ref); } let arg = GenericArg::Type(TypeRef::Tuple(param_types)); args.push(arg); } if let Some(ret_type) = ret_type { let type_ref = TypeRef::from_ast_opt(ret_type.type_ref()); bindings.push((name::OUTPUT_TYPE, type_ref)) } if args.is_empty() && bindings.is_empty() { None } else { Some(GenericArgs { args, has_self_type: false, bindings }) } } pub(crate) fn empty() -> GenericArgs { GenericArgs { args: Vec::new(), has_self_type: false, bindings: Vec::new() } } } impl From for Path { fn from(name: Name) -> Path { Path::from_simple_segments(PathKind::Plain, iter::once(name)) } } fn expand_use_tree( prefix: Option, tree: ast::UseTree, cb: &mut impl FnMut(Path, &ast::UseTree, bool, Option), ) { if let Some(use_tree_list) = tree.use_tree_list() { let prefix = match tree.path() { // E.g. use something::{{{inner}}}; None => prefix, // E.g. `use something::{inner}` (prefix is `None`, path is `something`) // or `use something::{path::{inner::{innerer}}}` (prefix is `something::path`, path is `inner`) Some(path) => match convert_path(prefix, path) { Some(it) => Some(it), None => return, // FIXME: report errors somewhere }, }; for child_tree in use_tree_list.use_trees() { expand_use_tree(prefix.clone(), child_tree, cb); } } else { let alias = tree.alias().and_then(|a| a.name()).map(|a| a.as_name()); if let Some(ast_path) = tree.path() { // Handle self in a path. // E.g. `use something::{self, <...>}` if ast_path.qualifier().is_none() { if let Some(segment) = ast_path.segment() { if segment.kind() == Some(ast::PathSegmentKind::SelfKw) { if let Some(prefix) = prefix { cb(prefix, &tree, false, alias); return; } } } } if let Some(path) = convert_path(prefix, ast_path) { let is_glob = tree.has_star(); cb(path, &tree, is_glob, alias) } // FIXME: report errors somewhere // We get here if we do } } } fn convert_path(prefix: Option, path: ast::Path) -> Option { let prefix = if let Some(qual) = path.qualifier() { Some(convert_path(prefix, qual)?) } else { prefix }; let segment = path.segment()?; let res = match segment.kind()? { ast::PathSegmentKind::Name(name) => { // no type args in use let mut res = prefix .unwrap_or_else(|| Path { kind: PathKind::Plain, segments: Vec::with_capacity(1) }); res.segments.push(PathSegment { name: name.as_name(), args_and_bindings: None, // no type args in use }); res } ast::PathSegmentKind::CrateKw => { if prefix.is_some() { return None; } Path::from_simple_segments(PathKind::Crate, iter::empty()) } ast::PathSegmentKind::SelfKw => { if prefix.is_some() { return None; } Path::from_simple_segments(PathKind::Self_, iter::empty()) } ast::PathSegmentKind::SuperKw => { if prefix.is_some() { return None; } Path::from_simple_segments(PathKind::Super, iter::empty()) } ast::PathSegmentKind::Type { .. } => { // not allowed in imports return None; } }; Some(res) } pub mod known { use super::{Path, PathKind}; use crate::name; pub fn std_iter_into_iterator() -> Path { Path::from_simple_segments( PathKind::Abs, vec![name::STD, name::ITER, name::INTO_ITERATOR_TYPE], ) } pub fn std_ops_try() -> Path { Path::from_simple_segments(PathKind::Abs, vec![name::STD, name::OPS, name::TRY_TYPE]) } pub fn std_result_result() -> Path { Path::from_simple_segments(PathKind::Abs, vec![name::STD, name::RESULT, name::RESULT_TYPE]) } pub fn std_future_future() -> Path { Path::from_simple_segments(PathKind::Abs, vec![name::STD, name::FUTURE, name::FUTURE_TYPE]) } pub fn std_boxed_box() -> Path { Path::from_simple_segments(PathKind::Abs, vec![name::STD, name::BOXED, name::BOX_TYPE]) } }