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// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use ast;
use attr;
use codemap::Span;
use diagnostic;
use visit;
use visit::Visitor;
struct MacroRegistrarContext {
registrars: Vec<(ast::NodeId, Span)> ,
}
impl Visitor<()> for MacroRegistrarContext {
fn visit_item(&mut self, item: &ast::Item, _: ()) {
match item.node {
ast::ItemFn(..) => {
if attr::contains_name(item.attrs.as_slice(),
"macro_registrar") {
self.registrars.push((item.id, item.span));
}
}
_ => {}
}
visit::walk_item(self, item, ());
}
}
pub fn find_macro_registrar(diagnostic: &diagnostic::SpanHandler,
krate: &ast::Crate) -> Option<ast::DefId> {
let mut ctx = MacroRegistrarContext { registrars: Vec::new() };
visit::walk_crate(&mut ctx, krate, ());
match ctx.registrars.len() {
0 => None,
1 => {
let (node_id, _) = ctx.registrars.pop().unwrap();
Some(ast::DefId {
krate: ast::LOCAL_CRATE,
node: node_id
})
},
_ => {
diagnostic.handler().err("multiple macro registration functions found");
for &(_, span) in ctx.registrars.iter() {
diagnostic.span_note(span, "one is here");
}
diagnostic.handler().abort_if_errors();
unreachable!();
}
}
}
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