use std::sync::Arc; use ra_syntax::{ast, AstNode}; use crate::{Name, AsName, type_ref::TypeRef}; #[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, // someday also bindings } /// A single generic argument. #[derive(Debug, Clone, PartialEq, Eq, Hash)] pub enum GenericArg { Type(TypeRef), // or lifetime... } #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] pub enum PathKind { Plain, Self_, Super, Crate, } impl Path { /// Calls `cb` with all paths, represented by this use item. pub fn expand_use_item<'a>( item: &'a ast::UseItem, mut cb: impl FnMut(Path, Option<&'a ast::PathSegment>), ) { if let Some(tree) = item.use_tree() { expand_use_tree(None, tree, &mut cb); } } /// 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()?; match segment.kind()? { ast::PathSegmentKind::Name(name) => { let args = segment .type_arg_list() .and_then(GenericArgs::from_ast) .map(Arc::new); let segment = PathSegment { name: name.as_name(), args_and_bindings: args, }; segments.push(segment); } 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<&ast::Path> { if let Some(q) = path.qualifier() { return Some(q); } // TODO: this bottom up traversal is not too precise. // Should we handle do a top-down analysiss, 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.len() == 0 } /// 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) } } impl GenericArgs { 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 and assoc type args ignored for now if args.len() > 0 { Some(GenericArgs { args }) } else { None } } } impl From for Path { fn from(name: Name) -> Path { Path { kind: PathKind::Plain, segments: vec![PathSegment { name, args_and_bindings: None, }], } } } fn expand_use_tree<'a>( prefix: Option, tree: &'a ast::UseTree, cb: &mut impl FnMut(Path, Option<&'a ast::PathSegment>), ) { 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, // TODO: report errors somewhere }, }; for child_tree in use_tree_list.use_trees() { expand_use_tree(prefix.clone(), child_tree, cb); } } else { 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, Some(segment)); return; } } } } if let Some(path) = convert_path(prefix, ast_path) { if tree.has_star() { cb(path, None) } else if let Some(segment) = ast_path.segment() { cb(path, Some(segment)) }; } // TODO: 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) => { 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 { kind: PathKind::Crate, segments: Vec::new(), } } ast::PathSegmentKind::SelfKw => { if prefix.is_some() { return None; } Path { kind: PathKind::Self_, segments: Vec::new(), } } ast::PathSegmentKind::SuperKw => { if prefix.is_some() { return None; } Path { kind: PathKind::Super, segments: Vec::new(), } } }; Some(res) }