use crate::base::ExtCtxt;
use crate::expand::{AstFragment, AstFragmentKind};
use rustc_ast::ast;
use rustc_ast::mut_visit::*;
use rustc_ast::ptr::P;
use rustc_span::source_map::{dummy_spanned, DUMMY_SP};
use smallvec::{smallvec, SmallVec};
use rustc_data_structures::fx::FxHashMap;
pub fn placeholder(
kind: AstFragmentKind,
id: ast::NodeId,
vis: Option<ast::Visibility>,
) -> AstFragment {
fn mac_placeholder() -> ast::MacCall {
ast::MacCall {
path: ast::Path { span: DUMMY_SP, segments: Vec::new() },
args: P(ast::MacArgs::Empty),
prior_type_ascription: None,
}
}
let ident = ast::Ident::invalid();
let attrs = Vec::new();
let vis = vis.unwrap_or_else(|| dummy_spanned(ast::VisibilityKind::Inherited));
let span = DUMMY_SP;
let expr_placeholder = || {
P(ast::Expr {
id,
span,
attrs: ast::AttrVec::new(),
kind: ast::ExprKind::MacCall(mac_placeholder()),
})
};
let ty = || P(ast::Ty { id, kind: ast::TyKind::MacCall(mac_placeholder()), span });
let pat = || P(ast::Pat { id, kind: ast::PatKind::MacCall(mac_placeholder()), span });
match kind {
AstFragmentKind::Expr => AstFragment::Expr(expr_placeholder()),
AstFragmentKind::OptExpr => AstFragment::OptExpr(Some(expr_placeholder())),
AstFragmentKind::Items => AstFragment::Items(smallvec![P(ast::Item {
id,
span,
ident,
vis,
attrs,
kind: ast::ItemKind::MacCall(mac_placeholder()),
tokens: None,
})]),
AstFragmentKind::TraitItems => AstFragment::TraitItems(smallvec![P(ast::AssocItem {
id,
span,
ident,
vis,
attrs,
kind: ast::AssocItemKind::MacCall(mac_placeholder()),
tokens: None,
})]),
AstFragmentKind::ImplItems => AstFragment::ImplItems(smallvec![P(ast::AssocItem {
id,
span,
ident,
vis,
attrs,
kind: ast::AssocItemKind::MacCall(mac_placeholder()),
tokens: None,
})]),
AstFragmentKind::ForeignItems => {
AstFragment::ForeignItems(smallvec![P(ast::ForeignItem {
id,
span,
ident,
vis,
attrs,
kind: ast::ForeignItemKind::MacCall(mac_placeholder()),
tokens: None,
})])
}
AstFragmentKind::Pat => AstFragment::Pat(P(ast::Pat {
id,
span,
kind: ast::PatKind::MacCall(mac_placeholder()),
})),
AstFragmentKind::Ty => {
AstFragment::Ty(P(ast::Ty { id, span, kind: ast::TyKind::MacCall(mac_placeholder()) }))
}
AstFragmentKind::Stmts => AstFragment::Stmts(smallvec![{
let mac = P((mac_placeholder(), ast::MacStmtStyle::Braces, ast::AttrVec::new()));
ast::Stmt { id, span, kind: ast::StmtKind::MacCall(mac) }
}]),
AstFragmentKind::Arms => AstFragment::Arms(smallvec![ast::Arm {
attrs: Default::default(),
body: expr_placeholder(),
guard: None,
id,
pat: pat(),
span,
is_placeholder: true,
}]),
AstFragmentKind::Fields => AstFragment::Fields(smallvec![ast::Field {
attrs: Default::default(),
expr: expr_placeholder(),
id,
ident,
is_shorthand: false,
span,
is_placeholder: true,
}]),
AstFragmentKind::FieldPats => AstFragment::FieldPats(smallvec![ast::FieldPat {
attrs: Default::default(),
id,
ident,
is_shorthand: false,
pat: pat(),
span,
is_placeholder: true,
}]),
AstFragmentKind::GenericParams => AstFragment::GenericParams(smallvec![{
ast::GenericParam {
attrs: Default::default(),
bounds: Default::default(),
id,
ident,
is_placeholder: true,
kind: ast::GenericParamKind::Lifetime,
}
}]),
AstFragmentKind::Params => AstFragment::Params(smallvec![ast::Param {
attrs: Default::default(),
id,
pat: pat(),
span,
ty: ty(),
is_placeholder: true,
}]),
AstFragmentKind::StructFields => AstFragment::StructFields(smallvec![ast::StructField {
attrs: Default::default(),
id,
ident: None,
span,
ty: ty(),
vis,
is_placeholder: true,
}]),
AstFragmentKind::Variants => AstFragment::Variants(smallvec![ast::Variant {
attrs: Default::default(),
data: ast::VariantData::Struct(Default::default(), false),
disr_expr: None,
id,
ident,
span,
vis,
is_placeholder: true,
}]),
}
}
pub struct PlaceholderExpander<'a, 'b> {
expanded_fragments: FxHashMap<ast::NodeId, AstFragment>,
cx: &'a mut ExtCtxt<'b>,
monotonic: bool,
}
impl<'a, 'b> PlaceholderExpander<'a, 'b> {
pub fn new(cx: &'a mut ExtCtxt<'b>, monotonic: bool) -> Self {
PlaceholderExpander { cx, expanded_fragments: FxHashMap::default(), monotonic }
}
pub fn add(&mut self, id: ast::NodeId, mut fragment: AstFragment) {
fragment.mut_visit_with(self);
self.expanded_fragments.insert(id, fragment);
}
fn remove(&mut self, id: ast::NodeId) -> AstFragment {
self.expanded_fragments.remove(&id).unwrap()
}
}
impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
if arm.is_placeholder {
self.remove(arm.id).make_arms()
} else {
noop_flat_map_arm(arm, self)
}
}
fn flat_map_field(&mut self, field: ast::Field) -> SmallVec<[ast::Field; 1]> {
if field.is_placeholder {
self.remove(field.id).make_fields()
} else {
noop_flat_map_field(field, self)
}
}
fn flat_map_field_pattern(&mut self, fp: ast::FieldPat) -> SmallVec<[ast::FieldPat; 1]> {
if fp.is_placeholder {
self.remove(fp.id).make_field_patterns()
} else {
noop_flat_map_field_pattern(fp, self)
}
}
fn flat_map_generic_param(
&mut self,
param: ast::GenericParam,
) -> SmallVec<[ast::GenericParam; 1]> {
if param.is_placeholder {
self.remove(param.id).make_generic_params()
} else {
noop_flat_map_generic_param(param, self)
}
}
fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
if p.is_placeholder {
self.remove(p.id).make_params()
} else {
noop_flat_map_param(p, self)
}
}
fn flat_map_struct_field(&mut self, sf: ast::StructField) -> SmallVec<[ast::StructField; 1]> {
if sf.is_placeholder {
self.remove(sf.id).make_struct_fields()
} else {
noop_flat_map_struct_field(sf, self)
}
}
fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
if variant.is_placeholder {
self.remove(variant.id).make_variants()
} else {
noop_flat_map_variant(variant, self)
}
}
fn flat_map_item(&mut self, item: P<ast::Item>) -> SmallVec<[P<ast::Item>; 1]> {
match item.kind {
ast::ItemKind::MacCall(_) => return self.remove(item.id).make_items(),
ast::ItemKind::MacroDef(_) => return smallvec![item],
_ => {}
}
noop_flat_map_item(item, self)
}
fn flat_map_trait_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
match item.kind {
ast::AssocItemKind::MacCall(_) => self.remove(item.id).make_trait_items(),
_ => noop_flat_map_assoc_item(item, self),
}
}
fn flat_map_impl_item(&mut self, item: P<ast::AssocItem>) -> SmallVec<[P<ast::AssocItem>; 1]> {
match item.kind {
ast::AssocItemKind::MacCall(_) => self.remove(item.id).make_impl_items(),
_ => noop_flat_map_assoc_item(item, self),
}
}
fn flat_map_foreign_item(
&mut self,
item: P<ast::ForeignItem>,
) -> SmallVec<[P<ast::ForeignItem>; 1]> {
match item.kind {
ast::ForeignItemKind::MacCall(_) => self.remove(item.id).make_foreign_items(),
_ => noop_flat_map_foreign_item(item, self),
}
}
fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
match expr.kind {
ast::ExprKind::MacCall(_) => *expr = self.remove(expr.id).make_expr(),
_ => noop_visit_expr(expr, self),
}
}
fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
match expr.kind {
ast::ExprKind::MacCall(_) => self.remove(expr.id).make_opt_expr(),
_ => noop_filter_map_expr(expr, self),
}
}
fn flat_map_stmt(&mut self, stmt: ast::Stmt) -> SmallVec<[ast::Stmt; 1]> {
let (style, mut stmts) = match stmt.kind {
ast::StmtKind::MacCall(mac) => (mac.1, self.remove(stmt.id).make_stmts()),
_ => return noop_flat_map_stmt(stmt, self),
};
if style == ast::MacStmtStyle::Semicolon {
if let Some(stmt) = stmts.pop() {
stmts.push(stmt.add_trailing_semicolon());
}
}
stmts
}
fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
match pat.kind {
ast::PatKind::MacCall(_) => *pat = self.remove(pat.id).make_pat(),
_ => noop_visit_pat(pat, self),
}
}
fn visit_ty(&mut self, ty: &mut P<ast::Ty>) {
match ty.kind {
ast::TyKind::MacCall(_) => *ty = self.remove(ty.id).make_ty(),
_ => noop_visit_ty(ty, self),
}
}
fn visit_block(&mut self, block: &mut P<ast::Block>) {
noop_visit_block(block, self);
for stmt in block.stmts.iter_mut() {
if self.monotonic {
assert_eq!(stmt.id, ast::DUMMY_NODE_ID);
stmt.id = self.cx.resolver.next_node_id();
}
}
}
fn visit_mod(&mut self, module: &mut ast::Mod) {
noop_visit_mod(module, self);
module.items.retain(|item| match item.kind {
ast::ItemKind::MacCall(_) if !self.cx.ecfg.keep_macs => false, _ => true,
});
}
fn visit_mac(&mut self, _mac: &mut ast::MacCall) {
}
}