move std_inject to libsyntax

2 files changed, 236 insertions, 0 deletions

diff --git a/src/libsyntax/lib.rs b/src/libsyntax/lib.rs
index ff481dd7299..8122aa1dcc2 100644
--- a/src/libsyntax/lib.rs
+++ b/src/libsyntax/lib.rs
@@ -67,6 +67,7 @@ pub mod owned_slice;
 pub mod parse;
 pub mod ptr;
 pub mod show_span;
+pub mod std_inject;
 pub mod test;
 pub mod visit;
 
diff --git a/src/libsyntax/std_inject.rs b/src/libsyntax/std_inject.rs
new file mode 100644
index 00000000000..8a7e14643c1
--- /dev/null
+++ b/src/libsyntax/std_inject.rs
@@ -0,0 +1,235 @@
+// 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 codemap::DUMMY_SP;
+use codemap;
+use fold::Folder;
+use fold;
+use owned_slice::OwnedSlice;
+use parse::token::InternedString;
+use parse::token::special_idents;
+use parse::token;
+use ptr::P;
+use util::small_vector::SmallVector;
+
+use std::mem;
+
+pub fn maybe_inject_crates_ref(krate: ast::Crate, alt_std_name: Option<String>, any_exe: bool)
+                               -> ast::Crate {
+    if use_std(&krate) {
+        inject_crates_ref(krate, alt_std_name, any_exe)
+    } else {
+        krate
+    }
+}
+
+pub fn maybe_inject_prelude(krate: ast::Crate) -> ast::Crate {
+    if use_std(&krate) {
+        inject_prelude(krate)
+    } else {
+        krate
+    }
+}
+
+fn use_std(krate: &ast::Crate) -> bool {
+    !attr::contains_name(krate.attrs.as_slice(), "no_std")
+}
+
+fn use_start(krate: &ast::Crate) -> bool {
+    !attr::contains_name(krate.attrs.as_slice(), "no_start")
+}
+
+fn no_prelude(attrs: &[ast::Attribute]) -> bool {
+    attr::contains_name(attrs, "no_implicit_prelude")
+}
+
+struct StandardLibraryInjector<'a> {
+    alt_std_name: Option<String>,
+    any_exe: bool,
+}
+
+impl<'a> fold::Folder for StandardLibraryInjector<'a> {
+    fn fold_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
+
+        // The name to use in `extern crate "name" as std;`
+        let actual_crate_name = match self.alt_std_name {
+            Some(ref s) => token::intern_and_get_ident(s.as_slice()),
+            None => token::intern_and_get_ident("std"),
+        };
+
+        let mut vis = vec!(ast::ViewItem {
+            node: ast::ViewItemExternCrate(token::str_to_ident("std"),
+                                           Some((actual_crate_name, ast::CookedStr)),
+                                           ast::DUMMY_NODE_ID),
+            attrs: vec!(
+                attr::mk_attr_outer(attr::mk_attr_id(), attr::mk_list_item(
+                        InternedString::new("phase"),
+                        vec!(
+                            attr::mk_word_item(InternedString::new("plugin")),
+                            attr::mk_word_item(InternedString::new("link")
+                        ))))),
+            vis: ast::Inherited,
+            span: DUMMY_SP
+        });
+
+        if use_start(&krate) && self.any_exe {
+            let visible_rt_name = "rt";
+            let actual_rt_name = "native";
+            // Gensym the ident so it can't be named
+            let visible_rt_name = token::gensym_ident(visible_rt_name);
+            let actual_rt_name = token::intern_and_get_ident(actual_rt_name);
+
+            vis.push(ast::ViewItem {
+                node: ast::ViewItemExternCrate(visible_rt_name,
+                                               Some((actual_rt_name, ast::CookedStr)),
+                                               ast::DUMMY_NODE_ID),
+                attrs: Vec::new(),
+                vis: ast::Inherited,
+                span: DUMMY_SP
+            });
+        }
+
+        // `extern crate` must be precede `use` items
+        mem::swap(&mut vis, &mut krate.module.view_items);
+        krate.module.view_items.push_all_move(vis);
+
+        // don't add #![no_std] here, that will block the prelude injection later.
+        // Add it during the prelude injection instead.
+
+        // Add #![feature(phase)] here, because we use #[phase] on extern crate std.
+        let feat_phase_attr = attr::mk_attr_inner(attr::mk_attr_id(),
+                                                  attr::mk_list_item(
+                                  InternedString::new("feature"),
+                                  vec![attr::mk_word_item(InternedString::new("phase"))],
+                              ));
+        // std_inject runs after feature checking so manually mark this attr
+        attr::mark_used(&feat_phase_attr);
+        krate.attrs.push(feat_phase_attr);
+
+        krate
+    }
+}
+
+fn inject_crates_ref(krate: ast::Crate,
+                     alt_std_name: Option<String>,
+                     any_exe: bool) -> ast::Crate {
+    let mut fold = StandardLibraryInjector {
+        alt_std_name: alt_std_name,
+        any_exe: any_exe,
+    };
+    fold.fold_crate(krate)
+}
+
+struct PreludeInjector<'a>;
+
+
+impl<'a> fold::Folder for PreludeInjector<'a> {
+    fn fold_crate(&mut self, mut krate: ast::Crate) -> ast::Crate {
+        // Add #![no_std] here, so we don't re-inject when compiling pretty-printed source.
+        // This must happen here and not in StandardLibraryInjector because this
+        // fold happens second.
+
+        let no_std_attr = attr::mk_attr_inner(attr::mk_attr_id(),
+                                              attr::mk_word_item(InternedString::new("no_std")));
+        // std_inject runs after feature checking so manually mark this attr
+        attr::mark_used(&no_std_attr);
+        krate.attrs.push(no_std_attr);
+
+        if !no_prelude(krate.attrs.as_slice()) {
+            // only add `use std::prelude::*;` if there wasn't a
+            // `#![no_implicit_prelude]` at the crate level.
+            // fold_mod() will insert glob path.
+            let globs_attr = attr::mk_attr_inner(attr::mk_attr_id(),
+                                                 attr::mk_list_item(
+                InternedString::new("feature"),
+                vec!(
+                    attr::mk_word_item(InternedString::new("globs")),
+                )));
+            // std_inject runs after feature checking so manually mark this attr
+            attr::mark_used(&globs_attr);
+            krate.attrs.push(globs_attr);
+
+            krate.module = self.fold_mod(krate.module);
+        }
+        krate
+    }
+
+    fn fold_item(&mut self, item: P<ast::Item>) -> SmallVector<P<ast::Item>> {
+        if !no_prelude(item.attrs.as_slice()) {
+            // only recur if there wasn't `#![no_implicit_prelude]`
+            // on this item, i.e. this means that the prelude is not
+            // implicitly imported though the whole subtree
+            fold::noop_fold_item(item, self)
+        } else {
+            SmallVector::one(item)
+        }
+    }
+
+    fn fold_mod(&mut self, ast::Mod {inner, view_items, items}: ast::Mod) -> ast::Mod {
+        let prelude_path = ast::Path {
+            span: DUMMY_SP,
+            global: false,
+            segments: vec!(
+                ast::PathSegment {
+                    identifier: token::str_to_ident("std"),
+                    lifetimes: Vec::new(),
+                    types: OwnedSlice::empty(),
+                },
+                ast::PathSegment {
+                    identifier: token::str_to_ident("prelude"),
+                    lifetimes: Vec::new(),
+                    types: OwnedSlice::empty(),
+                }),
+        };
+
+        let (crates, uses) = view_items.partitioned(|x| {
+            match x.node {
+                ast::ViewItemExternCrate(..) => true,
+                _ => false,
+            }
+        });
+
+        // add prelude after any `extern crate` but before any `use`
+        let mut view_items = crates;
+        let vp = P(codemap::dummy_spanned(ast::ViewPathGlob(prelude_path, ast::DUMMY_NODE_ID)));
+        view_items.push(ast::ViewItem {
+            node: ast::ViewItemUse(vp),
+            attrs: vec![ast::Attribute {
+                span: DUMMY_SP,
+                node: ast::Attribute_ {
+                    id: attr::mk_attr_id(),
+                    style: ast::AttrOuter,
+                    value: P(ast::MetaItem {
+                        span: DUMMY_SP,
+                        node: ast::MetaWord(token::get_name(
+                                special_idents::prelude_import.name)),
+                    }),
+                    is_sugared_doc: false,
+                },
+            }],
+            vis: ast::Inherited,
+            span: DUMMY_SP,
+        });
+        view_items.push_all_move(uses);
+
+        fold::noop_fold_mod(ast::Mod {
+            inner: inner,
+            view_items: view_items,
+            items: items
+        }, self)
+    }
+}
+
+fn inject_prelude(krate: ast::Crate) -> ast::Crate {
+    let mut fold = PreludeInjector;
+    fold.fold_crate(krate)
+}