| // Copyright 2012 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 std::cell::Cell; |
| use std::iter; |
| use edition::Edition; |
| use ext::hygiene::{Mark, SyntaxContext}; |
| use symbol::{Symbol, keywords}; |
| use syntax_pos::{DUMMY_SP, Span}; |
| use source_map::{ExpnInfo, MacroAttribute, dummy_spanned, hygiene, respan}; |
| use ptr::P; |
| use tokenstream::TokenStream; |
| |
| /// Craft a span that will be ignored by the stability lint's |
| /// call to source_map's `is_internal` check. |
| /// The expanded code uses the unstable `#[prelude_import]` attribute. |
| fn ignored_span(sp: Span) -> Span { |
| let mark = Mark::fresh(Mark::root()); |
| mark.set_expn_info(ExpnInfo { |
| call_site: DUMMY_SP, |
| def_site: None, |
| format: MacroAttribute(Symbol::intern("std_inject")), |
| allow_internal_unstable: true, |
| allow_internal_unsafe: false, |
| local_inner_macros: false, |
| edition: hygiene::default_edition(), |
| }); |
| sp.with_ctxt(SyntaxContext::empty().apply_mark(mark)) |
| } |
| |
| pub fn injected_crate_name() -> Option<&'static str> { |
| INJECTED_CRATE_NAME.with(|name| name.get()) |
| } |
| |
| thread_local! { |
| static INJECTED_CRATE_NAME: Cell<Option<&'static str>> = Cell::new(None); |
| } |
| |
| pub fn maybe_inject_crates_ref( |
| mut krate: ast::Crate, |
| alt_std_name: Option<&str>, |
| edition: Edition, |
| ) -> ast::Crate { |
| let rust_2018 = edition >= Edition::Edition2018; |
| |
| // the first name in this list is the crate name of the crate with the prelude |
| let names: &[&str] = if attr::contains_name(&krate.attrs, "no_core") { |
| return krate; |
| } else if attr::contains_name(&krate.attrs, "no_std") { |
| if attr::contains_name(&krate.attrs, "compiler_builtins") { |
| &["core"] |
| } else { |
| &["core", "compiler_builtins"] |
| } |
| } else { |
| &["std"] |
| }; |
| |
| // .rev() to preserve ordering above in combination with insert(0, ...) |
| let alt_std_name = alt_std_name.map(Symbol::intern); |
| for orig_name in names.iter().rev() { |
| let orig_name = Symbol::intern(orig_name); |
| let mut rename = orig_name; |
| // HACK(eddyb) gensym the injected crates on the Rust 2018 edition, |
| // so they don't accidentally interfere with the new import paths. |
| if rust_2018 { |
| rename = orig_name.gensymed(); |
| } |
| let orig_name = if rename != orig_name { |
| Some(orig_name) |
| } else { |
| None |
| }; |
| krate.module.items.insert(0, P(ast::Item { |
| attrs: vec![attr::mk_attr_outer(DUMMY_SP, |
| attr::mk_attr_id(), |
| attr::mk_word_item(ast::Ident::from_str("macro_use")))], |
| vis: dummy_spanned(ast::VisibilityKind::Inherited), |
| node: ast::ItemKind::ExternCrate(alt_std_name.or(orig_name)), |
| ident: ast::Ident::with_empty_ctxt(rename), |
| id: ast::DUMMY_NODE_ID, |
| span: DUMMY_SP, |
| tokens: None, |
| })); |
| } |
| |
| // the crates have been injected, the assumption is that the first one is the one with |
| // the prelude. |
| let name = names[0]; |
| |
| INJECTED_CRATE_NAME.with(|opt_name| opt_name.set(Some(name))); |
| |
| let span = ignored_span(DUMMY_SP); |
| krate.module.items.insert(0, P(ast::Item { |
| attrs: vec![ast::Attribute { |
| style: ast::AttrStyle::Outer, |
| path: ast::Path::from_ident(ast::Ident::new(Symbol::intern("prelude_import"), span)), |
| tokens: TokenStream::empty(), |
| id: attr::mk_attr_id(), |
| is_sugared_doc: false, |
| span, |
| }], |
| vis: respan(span.shrink_to_lo(), ast::VisibilityKind::Inherited), |
| node: ast::ItemKind::Use(P(ast::UseTree { |
| prefix: ast::Path { |
| segments: iter::once(keywords::CrateRoot.ident()) |
| .chain( |
| [name, "prelude", "v1"].iter().cloned() |
| .map(ast::Ident::from_str) |
| ).map(ast::PathSegment::from_ident).collect(), |
| span, |
| }, |
| kind: ast::UseTreeKind::Glob, |
| span, |
| })), |
| id: ast::DUMMY_NODE_ID, |
| ident: keywords::Invalid.ident(), |
| span, |
| tokens: None, |
| })); |
| |
| krate |
| } |