| // Copyright 2016 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 std::panic; |
| |
| use errors::FatalError; |
| use proc_macro::{TokenStream, __internal}; |
| use syntax::ast::{self, ItemKind, Attribute, Mac}; |
| use syntax::attr::{mark_used, mark_known}; |
| use syntax::source_map::Span; |
| use syntax::ext::base::*; |
| use syntax::visit::Visitor; |
| |
| struct MarkAttrs<'a>(&'a [ast::Name]); |
| |
| impl<'a> Visitor<'a> for MarkAttrs<'a> { |
| fn visit_attribute(&mut self, attr: &Attribute) { |
| if self.0.contains(&attr.name()) { |
| mark_used(attr); |
| mark_known(attr); |
| } |
| } |
| |
| fn visit_mac(&mut self, _mac: &Mac) {} |
| } |
| |
| pub struct ProcMacroDerive { |
| inner: fn(TokenStream) -> TokenStream, |
| attrs: Vec<ast::Name>, |
| } |
| |
| impl ProcMacroDerive { |
| pub fn new(inner: fn(TokenStream) -> TokenStream, attrs: Vec<ast::Name>) -> ProcMacroDerive { |
| ProcMacroDerive { inner: inner, attrs: attrs } |
| } |
| } |
| |
| impl MultiItemModifier for ProcMacroDerive { |
| fn expand(&self, |
| ecx: &mut ExtCtxt, |
| span: Span, |
| _meta_item: &ast::MetaItem, |
| item: Annotatable) |
| -> Vec<Annotatable> { |
| let item = match item { |
| Annotatable::Item(item) => item, |
| Annotatable::ImplItem(_) | |
| Annotatable::TraitItem(_) | |
| Annotatable::ForeignItem(_) | |
| Annotatable::Stmt(_) | |
| Annotatable::Expr(_) => { |
| ecx.span_err(span, "proc-macro derives may only be \ |
| applied to a struct, enum, or union"); |
| return Vec::new() |
| } |
| }; |
| match item.node { |
| ItemKind::Struct(..) | |
| ItemKind::Enum(..) | |
| ItemKind::Union(..) => {}, |
| _ => { |
| ecx.span_err(span, "proc-macro derives may only be \ |
| applied to a struct, enum, or union"); |
| return Vec::new() |
| } |
| } |
| |
| // Mark attributes as known, and used. |
| MarkAttrs(&self.attrs).visit_item(&item); |
| |
| let input = __internal::new_token_stream(ecx.resolver.eliminate_crate_var(item.clone())); |
| let res = __internal::set_sess(ecx, || { |
| let inner = self.inner; |
| panic::catch_unwind(panic::AssertUnwindSafe(|| inner(input))) |
| }); |
| |
| let stream = match res { |
| Ok(stream) => stream, |
| Err(e) => { |
| let msg = "proc-macro derive panicked"; |
| let mut err = ecx.struct_span_fatal(span, msg); |
| if let Some(s) = e.downcast_ref::<String>() { |
| err.help(&format!("message: {}", s)); |
| } |
| if let Some(s) = e.downcast_ref::<&'static str>() { |
| err.help(&format!("message: {}", s)); |
| } |
| |
| err.emit(); |
| FatalError.raise(); |
| } |
| }; |
| |
| let error_count_before = ecx.parse_sess.span_diagnostic.err_count(); |
| __internal::set_sess(ecx, || { |
| let msg = "proc-macro derive produced unparseable tokens"; |
| match __internal::token_stream_parse_items(stream) { |
| // fail if there have been errors emitted |
| Ok(_) if ecx.parse_sess.span_diagnostic.err_count() > error_count_before => { |
| ecx.struct_span_fatal(span, msg).emit(); |
| FatalError.raise(); |
| } |
| Ok(new_items) => new_items.into_iter().map(Annotatable::Item).collect(), |
| Err(_) => { |
| // FIXME: handle this better |
| ecx.struct_span_fatal(span, msg).emit(); |
| FatalError.raise(); |
| } |
| } |
| }) |
| } |
| } |