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use session::Session;
use metadata::creader::CrateReader;
use std::collections::{HashSet, HashMap};
use syntax::ast;
use syntax::attr;
use syntax::codemap::Span;
use syntax::parse::token;
use syntax::visit;
use syntax::visit::Visitor;
use syntax::attr::AttrMetaMethods;
struct MacroLoader<'a> {
sess: &'a Session,
span_whitelist: HashSet<Span>,
reader: CrateReader<'a>,
macros: Vec<ast::MacroDef>,
}
impl<'a> MacroLoader<'a> {
fn new(sess: &'a Session) -> MacroLoader<'a> {
MacroLoader {
sess: sess,
span_whitelist: HashSet::new(),
reader: CrateReader::new(sess),
macros: vec![],
}
}
}
pub fn read_macro_defs(sess: &Session, krate: &ast::Crate) -> Vec<ast::MacroDef> {
let mut loader = MacroLoader::new(sess);
for item in &krate.module.items {
if let ast::ItemExternCrate(_) = item.node {
loader.span_whitelist.insert(item.span);
}
}
visit::walk_crate(&mut loader, krate);
loader.macros
}
pub type MacroSelection = HashMap<token::InternedString, Span>;
impl<'a, 'v> Visitor<'v> for MacroLoader<'a> {
fn visit_item(&mut self, item: &ast::Item) {
match item.node {
ast::ItemExternCrate(_) => {}
_ => {
visit::walk_item(self, item);
return;
}
}
let mut import = Some(HashMap::new());
let mut reexport = HashMap::new();
for attr in &item.attrs {
let mut used = true;
match &attr.name()[..] {
"macro_use" => {
let names = attr.meta_item_list();
if names.is_none() {
import = None;
}
if let (Some(sel), Some(names)) = (import.as_mut(), names) {
for attr in names {
if let ast::MetaWord(ref name) = attr.node {
sel.insert(name.clone(), attr.span);
} else {
self.sess.span_err(attr.span, "bad macro import");
}
}
}
}
"macro_reexport" => {
let names = match attr.meta_item_list() {
Some(names) => names,
None => {
self.sess.span_err(attr.span, "bad macro reexport");
continue;
}
};
for attr in names {
if let ast::MetaWord(ref name) = attr.node {
reexport.insert(name.clone(), attr.span);
} else {
self.sess.span_err(attr.span, "bad macro reexport");
}
}
}
_ => used = false,
}
if used {
attr::mark_used(attr);
}
}
self.load_macros(item, import, reexport)
}
fn visit_mac(&mut self, _: &ast::Mac) {
}
}
impl<'a> MacroLoader<'a> {
fn load_macros<'b>(&mut self,
vi: &ast::Item,
import: Option<MacroSelection>,
reexport: MacroSelection) {
if let Some(sel) = import.as_ref() {
if sel.is_empty() && reexport.is_empty() {
return;
}
}
if !self.span_whitelist.contains(&vi.span) {
self.sess.span_err(vi.span, "an `extern crate` loading macros must be at \
the crate root");
return;
}
let macros = self.reader.read_exported_macros(vi);
let mut seen = HashSet::new();
for mut def in macros {
let name = token::get_ident(def.ident);
seen.insert(name.clone());
def.use_locally = match import.as_ref() {
None => true,
Some(sel) => sel.contains_key(&name),
};
def.export = reexport.contains_key(&name);
def.allow_internal_unstable = attr::contains_name(&def.attrs,
"allow_internal_unstable");
debug!("load_macros: loaded: {:?}", def);
self.macros.push(def);
}
if let Some(sel) = import.as_ref() {
for (name, span) in sel.iter() {
if !seen.contains(name) {
self.sess.span_err(*span, "imported macro not found");
}
}
}
for (name, span) in reexport.iter() {
if !seen.contains(name) {
self.sess.span_err(*span, "reexported macro not found");
}
}
}
}