| use attr::HasAttrs; |
| use ast; |
| use source_map::{hygiene, ExpnInfo, ExpnFormat}; |
| use ext::base::ExtCtxt; |
| use ext::build::AstBuilder; |
| use parse::parser::PathStyle; |
| use symbol::Symbol; |
| use syntax_pos::Span; |
| |
| use rustc_data_structures::fx::FxHashSet; |
| |
| pub fn collect_derives(cx: &mut ExtCtxt, attrs: &mut Vec<ast::Attribute>) -> Vec<ast::Path> { |
| let mut result = Vec::new(); |
| attrs.retain(|attr| { |
| if attr.path != "derive" { |
| return true; |
| } |
| if !attr.is_meta_item_list() { |
| cx.span_err(attr.span, |
| "attribute must be of the form `#[derive(Trait1, Trait2, ...)]`"); |
| return false; |
| } |
| |
| match attr.parse_list(cx.parse_sess, |
| |parser| parser.parse_path_allowing_meta(PathStyle::Mod)) { |
| Ok(ref traits) if traits.is_empty() => { |
| cx.span_warn(attr.span, "empty trait list in `derive`"); |
| false |
| } |
| Ok(traits) => { |
| result.extend(traits); |
| true |
| } |
| Err(mut e) => { |
| e.emit(); |
| false |
| } |
| } |
| }); |
| result |
| } |
| |
| pub fn add_derived_markers<T>(cx: &mut ExtCtxt, span: Span, traits: &[ast::Path], item: T) -> T |
| where T: HasAttrs, |
| { |
| let (mut names, mut pretty_name) = (FxHashSet::default(), "derive(".to_owned()); |
| for (i, path) in traits.iter().enumerate() { |
| if i > 0 { |
| pretty_name.push_str(", "); |
| } |
| pretty_name.push_str(&path.to_string()); |
| names.insert(unwrap_or!(path.segments.get(0), continue).ident.name); |
| } |
| pretty_name.push(')'); |
| |
| cx.current_expansion.mark.set_expn_info(ExpnInfo { |
| call_site: span, |
| def_site: None, |
| format: ExpnFormat::MacroAttribute(Symbol::intern(&pretty_name)), |
| allow_internal_unstable: true, |
| allow_internal_unsafe: false, |
| local_inner_macros: false, |
| edition: hygiene::default_edition(), |
| }); |
| |
| let span = span.with_ctxt(cx.backtrace()); |
| item.map_attrs(|mut attrs| { |
| if names.contains(&Symbol::intern("Eq")) && names.contains(&Symbol::intern("PartialEq")) { |
| let meta = cx.meta_word(span, Symbol::intern("structural_match")); |
| attrs.push(cx.attribute(span, meta)); |
| } |
| if names.contains(&Symbol::intern("Copy")) { |
| let meta = cx.meta_word(span, Symbol::intern("rustc_copy_clone_marker")); |
| attrs.push(cx.attribute(span, meta)); |
| } |
| attrs |
| }) |
| } |