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|
use crate::proc_macro_impl::EXEC_STRATEGY;
use crate::proc_macro_server;
use errors::FatalError;
use rustc_data_structures::sync::Lrc;
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::parse;
use syntax::parse::token::{self, Token};
use syntax::tokenstream;
use syntax::visit::Visitor;
use syntax_pos::DUMMY_SP;
struct MarkAttrs<'a>(&'a [ast::Name]);
impl<'a> Visitor<'a> for MarkAttrs<'a> {
fn visit_attribute(&mut self, attr: &Attribute) {
if let Some(ident) = attr.ident() {
if self.0.contains(&ident.name) {
mark_used(attr);
mark_known(attr);
}
}
}
fn visit_mac(&mut self, _mac: &Mac) {}
}
pub struct ProcMacroDerive {
pub client: proc_macro::bridge::client::Client<
fn(proc_macro::TokenStream) -> proc_macro::TokenStream,
>,
pub attrs: Vec<ast::Name>,
}
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 token = Token::Interpolated(Lrc::new(token::NtItem(item)));
let input = tokenstream::TokenTree::Token(DUMMY_SP, token).into();
let server = proc_macro_server::Rustc::new(ecx);
let stream = match self.client.run(&EXEC_STRATEGY, server, input) {
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.as_str() {
err.help(&format!("message: {}", s));
}
err.emit();
FatalError.raise();
}
};
let error_count_before = ecx.parse_sess.span_diagnostic.err_count();
let msg = "proc-macro derive produced unparseable tokens";
let mut parser = parse::stream_to_parser(ecx.parse_sess, stream);
let mut items = vec![];
loop {
match parser.parse_item() {
Ok(None) => break,
Ok(Some(item)) => {
items.push(Annotatable::Item(item))
}
Err(mut err) => {
// FIXME: handle this better
err.cancel();
ecx.struct_span_fatal(span, msg).emit();
FatalError.raise();
}
}
}
// fail if there have been errors emitted
if ecx.parse_sess.span_diagnostic.err_count() > error_count_before {
ecx.struct_span_fatal(span, msg).emit();
FatalError.raise();
}
items
}
}
|
