rust/crates/hir-expand/src/attrs.rs

379 lines
13 KiB
Rust

//! A higher level attributes based on TokenTree, with also some shortcuts.
use std::{fmt, ops};
use base_db::CrateId;
use cfg::CfgExpr;
use either::Either;
use intern::Interned;
use mbe::{syntax_node_to_token_tree, DelimiterKind, Punct};
use smallvec::{smallvec, SmallVec};
use syntax::{ast, match_ast, AstNode, SmolStr, SyntaxNode};
use triomphe::Arc;
use crate::{
db::ExpandDatabase,
hygiene::Hygiene,
mod_path::ModPath,
tt::{self, Subtree},
InFile,
};
/// Syntactical attributes, without filtering of `cfg_attr`s.
#[derive(Default, Debug, Clone, PartialEq, Eq)]
pub struct RawAttrs {
// FIXME: Make this a ThinArc
entries: Option<Arc<[Attr]>>,
}
impl ops::Deref for RawAttrs {
type Target = [Attr];
fn deref(&self) -> &[Attr] {
match &self.entries {
Some(it) => &*it,
None => &[],
}
}
}
impl RawAttrs {
pub const EMPTY: Self = Self { entries: None };
pub fn new(db: &dyn ExpandDatabase, owner: &dyn ast::HasAttrs, hygiene: &Hygiene) -> Self {
let entries = collect_attrs(owner)
.filter_map(|(id, attr)| match attr {
Either::Left(attr) => {
attr.meta().and_then(|meta| Attr::from_src(db, meta, hygiene, id))
}
Either::Right(comment) => comment.doc_comment().map(|doc| Attr {
id,
input: Some(Interned::new(AttrInput::Literal(SmolStr::new(doc)))),
path: Interned::new(ModPath::from(crate::name!(doc))),
}),
})
.collect::<Vec<_>>();
// FIXME: use `Arc::from_iter` when it becomes available
let entries: Arc<[Attr]> = Arc::from(entries);
Self { entries: if entries.is_empty() { None } else { Some(entries) } }
}
pub fn from_attrs_owner(db: &dyn ExpandDatabase, owner: InFile<&dyn ast::HasAttrs>) -> Self {
let hygiene = Hygiene::new(db, owner.file_id);
Self::new(db, owner.value, &hygiene)
}
pub fn merge(&self, other: Self) -> Self {
match (&self.entries, other.entries) {
(None, None) => Self::EMPTY,
(None, entries @ Some(_)) => Self { entries },
(Some(entries), None) => Self { entries: Some(entries.clone()) },
(Some(a), Some(b)) => {
let last_ast_index = a.last().map_or(0, |it| it.id.ast_index() + 1) as u32;
Self {
entries: Some(Arc::from(
a.iter()
.cloned()
.chain(b.iter().map(|it| {
let mut it = it.clone();
it.id.id = it.id.ast_index() as u32 + last_ast_index
| (it.id.cfg_attr_index().unwrap_or(0) as u32)
<< AttrId::AST_INDEX_BITS;
it
}))
// FIXME: use `Arc::from_iter` when it becomes available
.collect::<Vec<_>>(),
)),
}
}
}
}
/// Processes `cfg_attr`s, returning the resulting semantic `Attrs`.
// FIXME: This should return a different type
pub fn filter(self, db: &dyn ExpandDatabase, krate: CrateId) -> RawAttrs {
let has_cfg_attrs = self
.iter()
.any(|attr| attr.path.as_ident().map_or(false, |name| *name == crate::name![cfg_attr]));
if !has_cfg_attrs {
return self;
}
let crate_graph = db.crate_graph();
let new_attrs = Arc::from(
self.iter()
.flat_map(|attr| -> SmallVec<[_; 1]> {
let is_cfg_attr =
attr.path.as_ident().map_or(false, |name| *name == crate::name![cfg_attr]);
if !is_cfg_attr {
return smallvec![attr.clone()];
}
let subtree = match attr.token_tree_value() {
Some(it) => it,
_ => return smallvec![attr.clone()],
};
let (cfg, parts) = match parse_cfg_attr_input(subtree) {
Some(it) => it,
None => return smallvec![attr.clone()],
};
let index = attr.id;
let attrs = parts.enumerate().take(1 << AttrId::CFG_ATTR_BITS).filter_map(
|(idx, attr)| {
let tree = Subtree {
delimiter: tt::Delimiter::unspecified(),
token_trees: attr.to_vec(),
};
// FIXME hygiene
let hygiene = Hygiene::new_unhygienic();
Attr::from_tt(db, &tree, &hygiene, index.with_cfg_attr(idx))
},
);
let cfg_options = &crate_graph[krate].cfg_options;
let cfg = Subtree { delimiter: subtree.delimiter, token_trees: cfg.to_vec() };
let cfg = CfgExpr::parse(&cfg);
if cfg_options.check(&cfg) == Some(false) {
smallvec![]
} else {
cov_mark::hit!(cfg_attr_active);
attrs.collect()
}
})
// FIXME: use `Arc::from_iter` when it becomes available
.collect::<Vec<_>>(),
);
RawAttrs { entries: Some(new_attrs) }
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub struct AttrId {
id: u32,
}
// FIXME: This only handles a single level of cfg_attr nesting
// that is `#[cfg_attr(all(), cfg_attr(all(), cfg(any())))]` breaks again
impl AttrId {
const CFG_ATTR_BITS: usize = 7;
const AST_INDEX_MASK: usize = 0x00FF_FFFF;
const AST_INDEX_BITS: usize = Self::AST_INDEX_MASK.count_ones() as usize;
const CFG_ATTR_SET_BITS: u32 = 1 << 31;
pub fn ast_index(&self) -> usize {
self.id as usize & Self::AST_INDEX_MASK
}
pub fn cfg_attr_index(&self) -> Option<usize> {
if self.id & Self::CFG_ATTR_SET_BITS == 0 {
None
} else {
Some(self.id as usize >> Self::AST_INDEX_BITS)
}
}
pub fn with_cfg_attr(self, idx: usize) -> AttrId {
AttrId { id: self.id | (idx as u32) << Self::AST_INDEX_BITS | Self::CFG_ATTR_SET_BITS }
}
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Attr {
pub id: AttrId,
pub path: Interned<ModPath>,
pub input: Option<Interned<AttrInput>>,
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub enum AttrInput {
/// `#[attr = "string"]`
Literal(SmolStr),
/// `#[attr(subtree)]`
TokenTree(Box<(tt::Subtree, mbe::TokenMap)>),
}
impl fmt::Display for AttrInput {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
AttrInput::Literal(lit) => write!(f, " = \"{}\"", lit.escape_debug()),
AttrInput::TokenTree(tt) => tt.0.fmt(f),
}
}
}
impl Attr {
fn from_src(
db: &dyn ExpandDatabase,
ast: ast::Meta,
hygiene: &Hygiene,
id: AttrId,
) -> Option<Attr> {
let path = Interned::new(ModPath::from_src(db, ast.path()?, hygiene)?);
let input = if let Some(ast::Expr::Literal(lit)) = ast.expr() {
let value = match lit.kind() {
ast::LiteralKind::String(string) => string.value()?.into(),
_ => lit.syntax().first_token()?.text().trim_matches('"').into(),
};
Some(Interned::new(AttrInput::Literal(value)))
} else if let Some(tt) = ast.token_tree() {
let (tree, map) = syntax_node_to_token_tree(tt.syntax());
Some(Interned::new(AttrInput::TokenTree(Box::new((tree, map)))))
} else {
None
};
Some(Attr { id, path, input })
}
fn from_tt(
db: &dyn ExpandDatabase,
tt: &tt::Subtree,
hygiene: &Hygiene,
id: AttrId,
) -> Option<Attr> {
let (parse, _) = mbe::token_tree_to_syntax_node(tt, mbe::TopEntryPoint::MetaItem);
let ast = ast::Meta::cast(parse.syntax_node())?;
Self::from_src(db, ast, hygiene, id)
}
pub fn path(&self) -> &ModPath {
&self.path
}
}
impl Attr {
/// #[path = "string"]
pub fn string_value(&self) -> Option<&SmolStr> {
match self.input.as_deref()? {
AttrInput::Literal(it) => Some(it),
_ => None,
}
}
/// #[path(ident)]
pub fn single_ident_value(&self) -> Option<&tt::Ident> {
match self.input.as_deref()? {
AttrInput::TokenTree(tt) => match &*tt.0.token_trees {
[tt::TokenTree::Leaf(tt::Leaf::Ident(ident))] => Some(ident),
_ => None,
},
_ => None,
}
}
/// #[path TokenTree]
pub fn token_tree_value(&self) -> Option<&Subtree> {
match self.input.as_deref()? {
AttrInput::TokenTree(tt) => Some(&tt.0),
_ => None,
}
}
/// Parses this attribute as a token tree consisting of comma separated paths.
pub fn parse_path_comma_token_tree<'a>(
&'a self,
db: &'a dyn ExpandDatabase,
hygiene: &'a Hygiene,
) -> Option<impl Iterator<Item = ModPath> + 'a> {
let args = self.token_tree_value()?;
if args.delimiter.kind != DelimiterKind::Parenthesis {
return None;
}
let paths = args
.token_trees
.split(|tt| matches!(tt, tt::TokenTree::Leaf(tt::Leaf::Punct(Punct { char: ',', .. }))))
.filter_map(move |tts| {
if tts.is_empty() {
return None;
}
// FIXME: This is necessarily a hack. It'd be nice if we could avoid allocation here.
let subtree = tt::Subtree {
delimiter: tt::Delimiter::unspecified(),
token_trees: tts.into_iter().cloned().collect(),
};
let (parse, _) =
mbe::token_tree_to_syntax_node(&subtree, mbe::TopEntryPoint::MetaItem);
let meta = ast::Meta::cast(parse.syntax_node())?;
// Only simple paths are allowed.
if meta.eq_token().is_some() || meta.expr().is_some() || meta.token_tree().is_some()
{
return None;
}
let path = meta.path()?;
ModPath::from_src(db, path, hygiene)
});
Some(paths)
}
pub fn cfg(&self) -> Option<CfgExpr> {
if *self.path.as_ident()? == crate::name![cfg] {
self.token_tree_value().map(CfgExpr::parse)
} else {
None
}
}
}
pub fn collect_attrs(
owner: &dyn ast::HasAttrs,
) -> impl Iterator<Item = (AttrId, Either<ast::Attr, ast::Comment>)> {
let inner_attrs = inner_attributes(owner.syntax()).into_iter().flatten();
let outer_attrs =
ast::AttrDocCommentIter::from_syntax_node(owner.syntax()).filter(|el| match el {
Either::Left(attr) => attr.kind().is_outer(),
Either::Right(comment) => comment.is_outer(),
});
outer_attrs.chain(inner_attrs).enumerate().map(|(id, attr)| (AttrId { id: id as u32 }, attr))
}
fn inner_attributes(
syntax: &SyntaxNode,
) -> Option<impl Iterator<Item = Either<ast::Attr, ast::Comment>>> {
let node = match_ast! {
match syntax {
ast::SourceFile(_) => syntax.clone(),
ast::ExternBlock(it) => it.extern_item_list()?.syntax().clone(),
ast::Fn(it) => it.body()?.stmt_list()?.syntax().clone(),
ast::Impl(it) => it.assoc_item_list()?.syntax().clone(),
ast::Module(it) => it.item_list()?.syntax().clone(),
ast::BlockExpr(it) => {
use syntax::SyntaxKind::{BLOCK_EXPR , EXPR_STMT};
// Block expressions accept outer and inner attributes, but only when they are the outer
// expression of an expression statement or the final expression of another block expression.
let may_carry_attributes = matches!(
it.syntax().parent().map(|it| it.kind()),
Some(BLOCK_EXPR | EXPR_STMT)
);
if !may_carry_attributes {
return None
}
syntax.clone()
},
_ => return None,
}
};
let attrs = ast::AttrDocCommentIter::from_syntax_node(&node).filter(|el| match el {
Either::Left(attr) => attr.kind().is_inner(),
Either::Right(comment) => comment.is_inner(),
});
Some(attrs)
}
// Input subtree is: `(cfg, $(attr),+)`
// Split it up into a `cfg` subtree and the `attr` subtrees.
pub fn parse_cfg_attr_input(
subtree: &Subtree,
) -> Option<(&[tt::TokenTree], impl Iterator<Item = &[tt::TokenTree]>)> {
let mut parts = subtree
.token_trees
.split(|tt| matches!(tt, tt::TokenTree::Leaf(tt::Leaf::Punct(Punct { char: ',', .. }))));
let cfg = parts.next()?;
Some((cfg, parts.filter(|it| !it.is_empty())))
}