272 lines
10 KiB
Rust
272 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, HasAttrs};
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use feature_gate::{emit_feature_err, EXPLAIN_STMT_ATTR_SYNTAX, Features, get_features, GateIssue};
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use fold::Folder;
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use {fold, attr};
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use ast;
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use codemap::{Spanned, respan};
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use parse::{ParseSess, token};
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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 configuration.
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pub struct StripUnconfigured<'a> {
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pub config: &'a ast::CrateConfig,
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pub should_test: bool,
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pub sess: &'a ParseSess,
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pub features: Option<&'a Features>,
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}
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impl<'a> StripUnconfigured<'a> {
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fn configure<T: HasAttrs>(&mut self, node: T) -> Option<T> {
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let node = self.process_cfg_attrs(node);
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if self.in_cfg(node.attrs()) { Some(node) } else { None }
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}
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pub fn process_cfg_attrs<T: HasAttrs>(&mut self, node: T) -> T {
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node.map_attrs(|attrs| {
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attrs.into_iter().filter_map(|attr| self.process_cfg_attr(attr)).collect()
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})
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}
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fn process_cfg_attr(&mut self, attr: ast::Attribute) -> Option<ast::Attribute> {
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if !attr.check_name("cfg_attr") {
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return Some(attr);
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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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let msg = "expected `#[cfg_attr(<cfg pattern>, <attr>)]`";
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self.sess.span_diagnostic.span_err(attr.span, msg);
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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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let msg = "expected `#[cfg_attr(<cfg pattern>, <attr>)]`";
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self.sess.span_diagnostic.span_err(attr.span, msg);
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return None;
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}
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};
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if attr::cfg_matches(self.config, &cfg, self.sess, self.features) {
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self.process_cfg_attr(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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// Determine if a node with the given attributes should be included in this configuation.
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fn in_cfg(&mut self, attrs: &[ast::Attribute]) -> bool {
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attrs.iter().all(|attr| {
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// When not compiling with --test we should not compile the #[test] functions
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if !self.should_test && is_test_or_bench(attr) {
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return false;
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}
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let mis = match attr.node.value.node {
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ast::MetaItemKind::List(_, ref mis) if is_cfg(&attr) => mis,
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_ => return true
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};
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if mis.len() != 1 {
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self.sess.span_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(self.config, &mis[0], self.sess, self.features)
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})
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}
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// Visit attributes on expression and statements (but not attributes on items in blocks).
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fn visit_stmt_or_expr_attrs(&mut self, attrs: &[ast::Attribute]) {
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// flag the offending attributes
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for attr in attrs.iter() {
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if !self.features.map(|features| features.stmt_expr_attributes).unwrap_or(true) {
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emit_feature_err(&self.sess.span_diagnostic,
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"stmt_expr_attributes",
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attr.span,
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GateIssue::Language,
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EXPLAIN_STMT_ATTR_SYNTAX);
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}
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}
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}
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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(mut krate: ast::Crate, sess: &ParseSess, should_test: bool)
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-> (ast::Crate, Features) {
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let features;
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{
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let mut strip_unconfigured = StripUnconfigured {
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config: &krate.config.clone(),
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should_test: should_test,
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sess: sess,
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features: None,
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};
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let err_count = sess.span_diagnostic.err_count();
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let krate_attrs = strip_unconfigured.configure(krate.attrs.clone()).unwrap_or_default();
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features = get_features(&sess.span_diagnostic, &krate_attrs);
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if err_count < sess.span_diagnostic.err_count() {
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krate.attrs = krate_attrs.clone(); // Avoid reconfiguring malformed `cfg_attr`s
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}
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strip_unconfigured.features = Some(&features);
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krate = strip_unconfigured.fold_crate(krate);
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krate.attrs = krate_attrs;
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}
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(krate, features)
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}
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impl<'a> fold::Folder for StripUnconfigured<'a> {
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fn fold_foreign_mod(&mut self, foreign_mod: ast::ForeignMod) -> ast::ForeignMod {
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ast::ForeignMod {
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abi: foreign_mod.abi,
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items: foreign_mod.items.into_iter().filter_map(|item| {
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self.configure(item).map(|item| fold::noop_fold_foreign_item(item, self))
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}).collect(),
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}
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}
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fn fold_item_kind(&mut self, item: ast::ItemKind) -> ast::ItemKind {
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let fold_struct = |this: &mut Self, vdata| match vdata {
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ast::VariantData::Struct(fields, id) => {
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let fields = fields.into_iter().filter_map(|field| this.configure(field));
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ast::VariantData::Struct(fields.collect(), id)
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}
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ast::VariantData::Tuple(fields, id) => {
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let fields = fields.into_iter().filter_map(|field| this.configure(field));
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ast::VariantData::Tuple(fields.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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let item = match item {
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ast::ItemKind::Struct(def, generics) => {
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ast::ItemKind::Struct(fold_struct(self, def), generics)
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}
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ast::ItemKind::Enum(def, generics) => {
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let variants = def.variants.into_iter().filter_map(|v| {
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self.configure(v).map(|v| {
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Spanned {
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node: ast::Variant_ {
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name: v.node.name,
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attrs: v.node.attrs,
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data: fold_struct(self, v.node.data),
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disr_expr: v.node.disr_expr,
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},
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span: v.span
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}
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})
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});
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ast::ItemKind::Enum(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_kind(item, self)
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}
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fn fold_expr(&mut self, expr: P<ast::Expr>) -> P<ast::Expr> {
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self.visit_stmt_or_expr_attrs(expr.attrs());
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// If an expr is valid to cfg away it will have been removed by the
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// outer stmt or expression folder before descending in here.
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// Anything else is always required, and thus has to error out
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// in case of a cfg attr.
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//
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// NB: This is intentionally not part of the fold_expr() function
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// in order for fold_opt_expr() to be able to avoid this check
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if let Some(attr) = expr.attrs().iter().find(|a| is_cfg(a) || is_test_or_bench(a)) {
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let msg = "removing an expression is not supported in this position";
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self.sess.span_diagnostic.span_err(attr.span, msg);
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}
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let expr = self.process_cfg_attrs(expr);
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fold_expr(self, expr)
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}
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fn fold_opt_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
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self.configure(expr).map(|expr| fold_expr(self, expr))
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}
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fn fold_stmt(&mut self, stmt: ast::Stmt) -> SmallVector<ast::Stmt> {
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self.visit_stmt_or_expr_attrs(stmt.attrs());
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self.configure(stmt).map(|stmt| fold::noop_fold_stmt(stmt, self))
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.unwrap_or(SmallVector::zero())
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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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self.configure(item).map(|item| fold::noop_fold_item(item, self))
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.unwrap_or(SmallVector::zero())
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}
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fn fold_impl_item(&mut self, item: ast::ImplItem) -> SmallVector<ast::ImplItem> {
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self.configure(item).map(|item| fold::noop_fold_impl_item(item, self))
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.unwrap_or(SmallVector::zero())
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}
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fn fold_trait_item(&mut self, item: ast::TraitItem) -> SmallVector<ast::TraitItem> {
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self.configure(item).map(|item| fold::noop_fold_trait_item(item, self))
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.unwrap_or(SmallVector::zero())
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}
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fn fold_interpolated(&mut self, nt: token::Nonterminal) -> token::Nonterminal {
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// Don't configure interpolated AST (c.f. #34171).
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// Interpolated AST will get configured once the surrounding tokens are parsed.
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nt
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}
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}
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fn fold_expr(folder: &mut StripUnconfigured, expr: P<ast::Expr>) -> P<ast::Expr> {
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expr.map(|ast::Expr {id, span, node, attrs}| {
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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::ExprKind::Match(m, arms) => {
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ast::ExprKind::Match(m, arms.into_iter()
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.filter_map(|a| folder.configure(a))
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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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attrs: attrs,
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}, folder)
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})
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}
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fn is_cfg(attr: &ast::Attribute) -> bool {
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attr.check_name("cfg")
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}
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fn is_test_or_bench(attr: &ast::Attribute) -> bool {
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attr.check_name("test") || attr.check_name("bench")
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}
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