327 lines
10 KiB
Rust
327 lines
10 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 feature_gate::GatedCfg;
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use fold::Folder;
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use {ast, fold, attr};
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use codemap::{Spanned, respan};
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use ptr::P;
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use util::small_vector::SmallVector;
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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<F> where F: FnMut(&[ast::Attribute]) -> bool {
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in_cfg: F,
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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,
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feature_gated_cfgs: &mut Vec<GatedCfg>)
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-> ast::Crate
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{
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let krate = process_cfg_attr(diagnostic, krate, feature_gated_cfgs);
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let config = krate.config.clone();
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strip_items(krate, |attrs| in_cfg(diagnostic, &config, attrs, feature_gated_cfgs))
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}
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impl<F> fold::Folder for Context<F> where F: FnMut(&[ast::Attribute]) -> bool {
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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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fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
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fold_item(self, item)
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}
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}
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pub fn strip_items<F>(krate: ast::Crate, in_cfg: F) -> ast::Crate where
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F: FnMut(&[ast::Attribute]) -> bool,
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{
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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 fold_mod<F>(cx: &mut Context<F>,
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ast::Mod {inner, items}: ast::Mod)
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-> ast::Mod where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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ast::Mod {
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inner: inner,
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items: items.into_iter().flat_map(|a| {
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cx.fold_item(a).into_iter()
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}).collect()
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}
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}
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fn filter_foreign_item<F>(cx: &mut Context<F>,
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item: P<ast::ForeignItem>)
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-> Option<P<ast::ForeignItem>> where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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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<F>(cx: &mut Context<F>,
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ast::ForeignMod {abi, items}: ast::ForeignMod)
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-> ast::ForeignMod where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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ast::ForeignMod {
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abi: abi,
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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<F>(cx: &mut Context<F>, item: P<ast::Item>) -> SmallVector<P<ast::Item>> where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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if item_in_cfg(cx, &item) {
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SmallVector::one(item.map(|i| cx.fold_item_simple(i)))
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} else {
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SmallVector::zero()
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}
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}
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fn fold_item_underscore<F>(cx: &mut Context<F>, item: ast::Item_) -> ast::Item_ where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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let item = match item {
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ast::ItemImpl(u, o, a, b, c, impl_items) => {
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let impl_items = impl_items.into_iter()
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.filter(|ii| (cx.in_cfg)(&ii.attrs))
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.collect();
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ast::ItemImpl(u, o, a, b, c, impl_items)
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}
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ast::ItemTrait(u, a, b, methods) => {
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let methods = methods.into_iter()
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.filter(|ti| (cx.in_cfg)(&ti.attrs))
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.collect();
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ast::ItemTrait(u, a, b, 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 variants = def.variants.into_iter().filter_map(|v| {
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if !(cx.in_cfg)(&v.node.attrs) {
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None
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} else {
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Some(v.map(|Spanned {node: ast::Variant_ {name, attrs, data,
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disr_expr}, span}| {
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Spanned {
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node: ast::Variant_ {
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name: name,
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attrs: attrs,
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data: fold_struct(cx, data),
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disr_expr: disr_expr,
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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<F>(cx: &mut Context<F>, vdata: ast::VariantData) -> ast::VariantData where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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match vdata {
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ast::VariantData::Struct(fields, id) => {
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ast::VariantData::Struct(fields.into_iter().filter(|m| {
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(cx.in_cfg)(&m.node.attrs)
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}).collect(), id)
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}
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ast::VariantData::Tuple(fields, id) => {
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ast::VariantData::Tuple(fields.into_iter().filter(|m| {
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(cx.in_cfg)(&m.node.attrs)
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}).collect(), id)
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}
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ast::VariantData::Unit(id) => ast::VariantData::Unit(id)
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}
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}
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fn retain_stmt<F>(cx: &mut Context<F>, stmt: &ast::Stmt) -> bool where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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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<F>(cx: &mut Context<F>, b: P<ast::Block>) -> P<ast::Block> where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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b.map(|ast::Block {id, 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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ast::Block {
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id: id,
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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<F>(cx: &mut Context<F>, expr: P<ast::Expr>) -> P<ast::Expr> where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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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) => {
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ast::ExprMatch(m, arms.into_iter()
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.filter(|a| (cx.in_cfg)(&a.attrs))
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.collect())
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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<F>(cx: &mut Context<F>, item: &ast::Item) -> bool where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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return (cx.in_cfg)(&item.attrs);
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}
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fn foreign_item_in_cfg<F>(cx: &mut Context<F>, item: &ast::ForeignItem) -> bool where
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F: FnMut(&[ast::Attribute]) -> bool
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{
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return (cx.in_cfg)(&item.attrs);
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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],
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feature_gated_cfgs: &mut Vec<GatedCfg>) -> 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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feature_gated_cfgs)
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})
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}
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struct CfgAttrFolder<'a, 'b> {
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diag: &'a SpanHandler,
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config: ast::CrateConfig,
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feature_gated_cfgs: &'b mut Vec<GatedCfg>
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}
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// Process `#[cfg_attr]`.
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fn process_cfg_attr(diagnostic: &SpanHandler, krate: ast::Crate,
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feature_gated_cfgs: &mut Vec<GatedCfg>) -> ast::Crate {
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let mut fld = CfgAttrFolder {
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diag: diagnostic,
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config: krate.config.clone(),
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feature_gated_cfgs: feature_gated_cfgs,
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};
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fld.fold_crate(krate)
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}
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impl<'a,'b> fold::Folder for CfgAttrFolder<'a,'b> {
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fn fold_attribute(&mut self, attr: ast::Attribute) -> Option<ast::Attribute> {
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if !attr.check_name("cfg_attr") {
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return fold::noop_fold_attribute(attr, self);
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}
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let attr_list = match attr.meta_item_list() {
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Some(attr_list) => attr_list,
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None => {
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self.diag.span_err(attr.span, "expected `#[cfg_attr(<cfg pattern>, <attr>)]`");
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return None;
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}
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};
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let (cfg, mi) = match (attr_list.len(), attr_list.get(0), attr_list.get(1)) {
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(2, Some(cfg), Some(mi)) => (cfg, mi),
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_ => {
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self.diag.span_err(attr.span, "expected `#[cfg_attr(<cfg pattern>, <attr>)]`");
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return None;
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}
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};
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if attr::cfg_matches(self.diag, &self.config[..], &cfg,
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self.feature_gated_cfgs) {
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Some(respan(mi.span, ast::Attribute_ {
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id: attr::mk_attr_id(),
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style: attr.node.style,
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value: mi.clone(),
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is_sugared_doc: false,
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}))
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} else {
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None
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}
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}
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// Need the ability to run pre-expansion.
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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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