1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Used by `rustc` when loading a crate with exported macros.
14 use metadata::creader::CrateReader;
16 use std::collections::{HashSet, HashMap};
17 use syntax::codemap::Span;
18 use syntax::parse::token;
22 use syntax::visit::Visitor;
23 use syntax::attr::AttrMetaMethods;
25 struct MacroLoader<'a> {
27 span_whitelist: HashSet<Span>,
28 reader: CrateReader<'a>,
29 macros: Vec<ast::MacroDef>,
32 impl<'a> MacroLoader<'a> {
33 fn new(sess: &'a Session) -> MacroLoader<'a> {
36 span_whitelist: HashSet::new(),
37 reader: CrateReader::new(sess),
43 /// Read exported macros.
44 pub fn read_macro_defs(sess: &Session, krate: &ast::Crate) -> Vec<ast::MacroDef> {
45 let mut loader = MacroLoader::new(sess);
47 // We need to error on `#[macro_use] extern crate` when it isn't at the
48 // crate root, because `$crate` won't work properly. Identify these by
49 // spans, because the crate map isn't set up yet.
50 for item in &krate.module.items {
51 if let ast::ItemExternCrate(_) = item.node {
52 loader.span_whitelist.insert(item.span);
56 visit::walk_crate(&mut loader, krate);
61 pub type MacroSelection = HashMap<token::InternedString, Span>;
63 // note that macros aren't expanded yet, and therefore macros can't add macro imports.
64 impl<'a, 'v> Visitor<'v> for MacroLoader<'a> {
65 fn visit_item(&mut self, item: &ast::Item) {
66 // We're only interested in `extern crate`.
68 ast::ItemExternCrate(_) => {}
70 visit::walk_item(self, item);
75 // Parse the attributes relating to macros.
76 let mut import = Some(HashMap::new()); // None => load all
77 let mut reexport = HashMap::new();
79 for attr in &item.attrs {
81 match &attr.name()[..] {
83 let names = attr.meta_item_list();
85 // no names => load all
88 if let (Some(sel), Some(names)) = (import.as_mut(), names) {
90 if let ast::MetaWord(ref name) = attr.node {
91 sel.insert(name.clone(), attr.span);
93 self.sess.span_err(attr.span, "bad macro import");
99 let names = match attr.meta_item_list() {
100 Some(names) => names,
102 self.sess.span_err(attr.span, "bad macro reexport");
108 if let ast::MetaWord(ref name) = attr.node {
109 reexport.insert(name.clone(), attr.span);
111 self.sess.span_err(attr.span, "bad macro reexport");
118 attr::mark_used(attr);
122 self.load_macros(item, import, reexport)
125 fn visit_mac(&mut self, _: &ast::Mac) {
126 // bummer... can't see macro imports inside macros.
131 impl<'a> MacroLoader<'a> {
132 fn load_macros<'b>(&mut self,
134 import: Option<MacroSelection>,
135 reexport: MacroSelection) {
136 if let Some(sel) = import.as_ref() {
137 if sel.is_empty() && reexport.is_empty() {
142 if !self.span_whitelist.contains(&vi.span) {
143 self.sess.span_err(vi.span, "an `extern crate` loading macros must be at \
148 let macros = self.reader.read_exported_macros(vi);
149 let mut seen = HashSet::new();
151 for mut def in macros {
152 let name = def.ident.name.as_str();
154 def.use_locally = match import.as_ref() {
156 Some(sel) => sel.contains_key(&name),
158 def.export = reexport.contains_key(&name);
159 def.allow_internal_unstable = attr::contains_name(&def.attrs,
160 "allow_internal_unstable");
161 debug!("load_macros: loaded: {:?}", def);
162 self.macros.push(def);
166 if let Some(sel) = import.as_ref() {
167 for (name, span) in sel {
168 if !seen.contains(&name) {
169 self.sess.span_err(*span, "imported macro not found");
174 for (name, span) in &reexport {
175 if !seen.contains(&name) {
176 self.sess.span_err(*span, "reexported macro not found");