268 lines
9.0 KiB
Rust
268 lines
9.0 KiB
Rust
// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use attr::AttrMetaMethods;
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use diagnostic::SpanHandler;
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use fold::Folder;
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use {ast, fold, attr};
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use codemap::Spanned;
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use ptr::P;
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/// A folder that strips out items that do not belong in the current
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/// configuration.
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struct Context<'a> {
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in_cfg: |attrs: &[ast::Attribute]|: 'a -> bool,
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}
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// Support conditional compilation by transforming the AST, stripping out
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// any items that do not belong in the current configuration
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pub fn strip_unconfigured_items(diagnostic: &SpanHandler, krate: ast::Crate) -> ast::Crate {
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let config = krate.config.clone();
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strip_items(krate, |attrs| in_cfg(diagnostic, config.as_slice(), attrs))
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}
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impl<'a> fold::Folder for Context<'a> {
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fn fold_mod(&mut self, module: ast::Mod) -> ast::Mod {
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fold_mod(self, module)
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}
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fn fold_block(&mut self, block: P<ast::Block>) -> P<ast::Block> {
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fold_block(self, block)
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}
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fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
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fold_foreign_mod(self, foreign_mod)
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}
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fn fold_item_underscore(&mut self, item: ast::Item_) -> ast::Item_ {
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fold_item_underscore(self, item)
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}
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fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
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fold_expr(self, expr)
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}
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fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
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fold::noop_fold_mac(mac, self)
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}
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}
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pub fn strip_items(krate: ast::Crate,
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in_cfg: |attrs: &[ast::Attribute]| -> bool)
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-> ast::Crate {
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let mut ctxt = Context {
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in_cfg: in_cfg,
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};
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ctxt.fold_crate(krate)
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}
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fn filter_view_item(cx: &mut Context, view_item: ast::ViewItem) -> Option<ast::ViewItem> {
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if view_item_in_cfg(cx, &view_item) {
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Some(view_item)
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} else {
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None
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}
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}
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fn fold_mod(cx: &mut Context, ast::Mod {inner, view_items, items}: ast::Mod) -> ast::Mod {
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ast::Mod {
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inner: inner,
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view_items: view_items.into_iter().filter_map(|a| {
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filter_view_item(cx, a).map(|x| cx.fold_view_item(x))
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}).collect(),
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items: items.into_iter().filter_map(|a| {
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if item_in_cfg(cx, &*a) {
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Some(cx.fold_item(a))
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} else {
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None
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}
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}).flat_map(|x| x.into_iter()).collect()
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}
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}
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fn filter_foreign_item(cx: &mut Context, item: P<ast::ForeignItem>)
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-> Option<P<ast::ForeignItem>> {
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if foreign_item_in_cfg(cx, &*item) {
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Some(item)
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} else {
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None
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}
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}
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fn fold_foreign_mod(cx: &mut Context, ast::ForeignMod {abi, view_items, items}: ast::ForeignMod)
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-> ast::ForeignMod {
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ast::ForeignMod {
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abi: abi,
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view_items: view_items.into_iter().filter_map(|a| {
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filter_view_item(cx, a).map(|x| cx.fold_view_item(x))
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}).collect(),
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items: items.into_iter()
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.filter_map(|a| filter_foreign_item(cx, a))
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.collect()
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}
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}
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fn fold_item_underscore(cx: &mut Context, item: ast::Item_) -> ast::Item_ {
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let item = match item {
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ast::ItemImpl(a, b, c, impl_items) => {
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let impl_items = impl_items.into_iter()
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.filter(|ii| impl_item_in_cfg(cx, ii))
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.collect();
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ast::ItemImpl(a, b, c, impl_items)
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}
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ast::ItemTrait(a, b, c, methods) => {
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let methods = methods.into_iter()
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.filter(|m| trait_method_in_cfg(cx, m))
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.collect();
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ast::ItemTrait(a, b, c, methods)
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}
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ast::ItemStruct(def, generics) => {
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ast::ItemStruct(fold_struct(cx, def), generics)
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}
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ast::ItemEnum(def, generics) => {
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let mut variants = def.variants.into_iter().filter_map(|v| {
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if !(cx.in_cfg)(v.node.attrs.as_slice()) {
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None
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} else {
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Some(v.map(|Spanned {node: ast::Variant_ {id, name, attrs, kind,
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disr_expr, vis}, span}| {
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Spanned {
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node: ast::Variant_ {
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id: id,
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name: name,
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attrs: attrs,
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kind: match kind {
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ast::TupleVariantKind(..) => kind,
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ast::StructVariantKind(def) => {
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ast::StructVariantKind(fold_struct(cx, def))
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}
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},
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disr_expr: disr_expr,
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vis: vis
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},
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span: span
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}
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}))
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}
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});
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ast::ItemEnum(ast::EnumDef {
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variants: variants.collect(),
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}, generics)
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}
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item => item,
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};
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fold::noop_fold_item_underscore(item, cx)
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}
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fn fold_struct(cx: &mut Context, def: P<ast::StructDef>) -> P<ast::StructDef> {
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def.map(|ast::StructDef { fields, ctor_id }| {
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ast::StructDef {
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fields: fields.into_iter().filter(|m| {
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(cx.in_cfg)(m.node.attrs.as_slice())
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}).collect(),
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ctor_id: ctor_id,
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}
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})
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}
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fn retain_stmt(cx: &mut Context, stmt: &ast::Stmt) -> bool {
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match stmt.node {
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ast::StmtDecl(ref decl, _) => {
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match decl.node {
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ast::DeclItem(ref item) => {
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item_in_cfg(cx, &**item)
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}
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_ => true
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}
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}
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_ => true
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}
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}
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fn fold_block(cx: &mut Context, b: P<ast::Block>) -> P<ast::Block> {
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b.map(|ast::Block {id, view_items, stmts, expr, rules, span}| {
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let resulting_stmts: Vec<P<ast::Stmt>> =
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stmts.into_iter().filter(|a| retain_stmt(cx, &**a)).collect();
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let resulting_stmts = resulting_stmts.into_iter()
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.flat_map(|stmt| cx.fold_stmt(stmt).into_iter())
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.collect();
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let filtered_view_items = view_items.into_iter().filter_map(|a| {
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filter_view_item(cx, a).map(|x| cx.fold_view_item(x))
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}).collect();
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ast::Block {
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id: id,
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view_items: filtered_view_items,
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stmts: resulting_stmts,
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expr: expr.map(|x| cx.fold_expr(x)),
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rules: rules,
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span: span,
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}
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})
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}
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fn fold_expr(cx: &mut Context, expr: P<ast::Expr>) -> P<ast::Expr> {
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expr.map(|ast::Expr {id, span, node}| {
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fold::noop_fold_expr(ast::Expr {
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id: id,
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node: match node {
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ast::ExprMatch(m, arms, source) => {
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ast::ExprMatch(m, arms.into_iter()
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.filter(|a| (cx.in_cfg)(a.attrs.as_slice()))
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.collect(), source)
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}
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_ => node
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},
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span: span
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}, cx)
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})
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}
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fn item_in_cfg(cx: &mut Context, item: &ast::Item) -> bool {
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return (cx.in_cfg)(item.attrs.as_slice());
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}
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fn foreign_item_in_cfg(cx: &mut Context, item: &ast::ForeignItem) -> bool {
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return (cx.in_cfg)(item.attrs.as_slice());
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}
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fn view_item_in_cfg(cx: &mut Context, item: &ast::ViewItem) -> bool {
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return (cx.in_cfg)(item.attrs.as_slice());
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}
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fn trait_method_in_cfg(cx: &mut Context, meth: &ast::TraitItem) -> bool {
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match *meth {
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ast::RequiredMethod(ref meth) => (cx.in_cfg)(meth.attrs.as_slice()),
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ast::ProvidedMethod(ref meth) => (cx.in_cfg)(meth.attrs.as_slice()),
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ast::TypeTraitItem(ref typ) => (cx.in_cfg)(typ.attrs.as_slice()),
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}
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}
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fn impl_item_in_cfg(cx: &mut Context, impl_item: &ast::ImplItem) -> bool {
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match *impl_item {
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ast::MethodImplItem(ref meth) => (cx.in_cfg)(meth.attrs.as_slice()),
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ast::TypeImplItem(ref typ) => (cx.in_cfg)(typ.attrs.as_slice()),
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}
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}
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// Determine if an item should be translated in the current crate
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// configuration based on the item's attributes
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fn in_cfg(diagnostic: &SpanHandler, cfg: &[P<ast::MetaItem>], attrs: &[ast::Attribute]) -> bool {
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attrs.iter().all(|attr| {
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let mis = match attr.node.value.node {
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ast::MetaList(_, ref mis) if attr.check_name("cfg") => mis,
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_ => return true
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};
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if mis.len() != 1 {
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diagnostic.span_err(attr.span, "expected 1 cfg-pattern");
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return true;
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}
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attr::cfg_matches(diagnostic, cfg, &*mis[0])
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})
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}
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