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|
//! FIXME: write short doc here
use std::{iter, sync::Arc};
use hir_expand::db::AstDatabase;
use ra_db::CrateId;
use ra_syntax::{
ast::{self, NameOwner, TypeAscriptionOwner},
AstNode,
};
use crate::{
name::{self, AsName, Name},
type_ref::TypeRef,
Source,
};
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct Path {
pub kind: PathKind,
pub segments: Vec<PathSegment>,
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct PathSegment {
pub name: Name,
pub args_and_bindings: Option<Arc<GenericArgs>>,
}
/// Generic arguments to a path segment (e.g. the `i32` in `Option<i32>`). This
/// can (in the future) also include bindings of associated types, like in
/// `Iterator<Item = Foo>`.
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct GenericArgs {
pub args: Vec<GenericArg>,
/// This specifies whether the args contain a Self type as the first
/// element. This is the case for path segments like `<T as Trait>`, where
/// `T` is actually a type parameter for the path `Trait` specifying the
/// Self type. Otherwise, when we have a path `Trait<X, Y>`, the Self type
/// is left out.
pub has_self_type: bool,
/// Associated type bindings like in `Iterator<Item = T>`.
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 `<T>::foo`
Type(Box<TypeRef>),
// `$crate` from macro expansion
DollarCrate(CrateId),
}
impl Path {
/// Calls `cb` with all paths, represented by this use item.
pub fn expand_use_item(
item_src: Source<ast::UseItem>,
db: &impl AstDatabase,
mut cb: impl FnMut(Path, &ast::UseTree, bool, Option<Name>),
) {
if let Some(tree) = item_src.ast.use_tree() {
expand_use_tree(None, tree, &|| item_src.file_id.macro_crate(db), &mut cb);
}
}
pub fn from_simple_segments(kind: PathKind, segments: impl IntoIterator<Item = Name>) -> Path {
Path {
kind,
segments: segments
.into_iter()
.map(|name| PathSegment { name, args_and_bindings: None })
.collect(),
}
}
/// Converts an `ast::Path` to `Path`. Works with use trees.
/// DEPRECATED: It does not handle `$crate` from macro call.
pub fn from_ast(path: ast::Path) -> Option<Path> {
Path::parse(path, &|| None)
}
/// Converts an `ast::Path` to `Path`. Works with use trees.
/// It correctly handles `$crate` based path from macro call.
pub fn from_src(source: Source<ast::Path>, db: &impl AstDatabase) -> Option<Path> {
let file_id = source.file_id;
Path::parse(source.ast, &|| file_id.macro_crate(db))
}
fn parse(mut path: ast::Path, macro_crate: &impl Fn() -> Option<CrateId>) -> Option<Path> {
let mut kind = PathKind::Plain;
let mut segments = Vec::new();
loop {
let segment = path.segment()?;
if segment.has_colon_colon() {
kind = PathKind::Abs;
}
match segment.kind()? {
ast::PathSegmentKind::Name(name) => {
if name.text() == "$crate" {
if let Some(macro_crate) = macro_crate() {
kind = PathKind::DollarCrate(macro_crate);
break;
}
}
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 {
// <T>::foo
None => {
kind = PathKind::Type(Box::new(self_type));
}
// <T as Trait<A>>::Foo desugars to Trait<Self=T, A>::Foo
Some(trait_ref) => {
let path = Path::parse(trait_ref.path()?, macro_crate)?;
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<ast::Path> {
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<Name> {
self.as_ident().and_then(|name| Some(name.clone()))
}
pub fn is_type_relative(&self) -> bool {
match self.kind {
PathKind::Type(_) => true,
_ => false,
}
}
}
impl GenericArgs {
pub fn from_ast(node: ast::TypeArgList) -> Option<GenericArgs> {
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<ast::ParamList>,
ret_type: Option<ast::RetType>,
) -> Option<GenericArgs> {
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<Name> for Path {
fn from(name: Name) -> Path {
Path::from_simple_segments(PathKind::Plain, iter::once(name))
}
}
fn expand_use_tree(
prefix: Option<Path>,
tree: ast::UseTree,
macro_crate: &impl Fn() -> Option<CrateId>,
cb: &mut impl FnMut(Path, &ast::UseTree, bool, Option<Name>),
) {
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, macro_crate) {
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, macro_crate, 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, macro_crate) {
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>,
path: ast::Path,
macro_crate: &impl Fn() -> Option<CrateId>,
) -> Option<Path> {
let prefix = if let Some(qual) = path.qualifier() {
Some(convert_path(prefix, qual, macro_crate)?)
} else {
prefix
};
let segment = path.segment()?;
let res = match segment.kind()? {
ast::PathSegmentKind::Name(name) => {
if name.text() == "$crate" {
if let Some(krate) = macro_crate() {
return Some(Path::from_simple_segments(
PathKind::DollarCrate(krate),
iter::empty(),
));
}
}
// 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])
}
}
|