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// Copyright 2014 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.
//! A pass that annotates every item and method with its stability level,
//! propagating default levels lexically from parent to children ast nodes.
use util::nodemap::{NodeMap, DefIdMap};
use syntax::codemap::Span;
use syntax::{attr, visit};
use syntax::ast::{Attribute, Block, Crate, DefId, FnDecl, NodeId, Variant};
use syntax::ast::{Item, Required, Provided, TraitMethod, TypeMethod, Method};
use syntax::ast::{Generics, StructDef, Ident};
use syntax::ast_util::is_local;
use syntax::attr::Stability;
use syntax::visit::{FnKind, FkMethod, Visitor};
use metadata::{cstore, csearch};
/// A stability index, giving the stability level for items and methods.
pub struct Index {
// stability for crate-local items; unmarked stability == no entry
local: NodeMap<Stability>,
// cache for extern-crate items; unmarked stability == entry with None
extern_cache: DefIdMap<Option<Stability>>
}
// A private tree-walker for producing an Index.
struct Annotator {
index: Index
}
impl Annotator {
// Determine the stability for a node based on its attributes and inherited
// stability. The stability is recorded in the index and returned.
fn annotate(&mut self, id: NodeId, attrs: &[Attribute],
parent: Option<Stability>) -> Option<Stability> {
match attr::find_stability(attrs).or(parent) {
Some(stab) => {
self.index.local.insert(id, stab.clone());
Some(stab)
}
None => None
}
}
}
impl Visitor<Option<Stability>> for Annotator {
fn visit_item(&mut self, i: &Item, parent: Option<Stability>) {
let stab = self.annotate(i.id, i.attrs.as_slice(), parent);
visit::walk_item(self, i, stab)
}
fn visit_fn(&mut self, fk: &FnKind, fd: &FnDecl, b: &Block,
s: Span, _: NodeId, parent: Option<Stability>) {
let stab = match *fk {
FkMethod(_, _, meth) =>
self.annotate(meth.id, meth.attrs.as_slice(), parent),
_ => parent
};
visit::walk_fn(self, fk, fd, b, s, stab)
}
fn visit_trait_method(&mut self, t: &TraitMethod, parent: Option<Stability>) {
let stab = match *t {
Required(TypeMethod {attrs: ref attrs, id: id, ..}) =>
self.annotate(id, attrs.as_slice(), parent),
// work around lack of pattern matching for @ types
Provided(method) => match *method {
Method {attrs: ref attrs, id: id, ..} =>
self.annotate(id, attrs.as_slice(), parent)
}
};
visit::walk_trait_method(self, t, stab)
}
fn visit_variant(&mut self, v: &Variant, g: &Generics, parent: Option<Stability>) {
let stab = self.annotate(v.node.id, v.node.attrs.as_slice(), parent);
visit::walk_variant(self, v, g, stab)
}
fn visit_struct_def(&mut self, s: &StructDef, _: Ident, _: &Generics,
_: NodeId, parent: Option<Stability>) {
s.ctor_id.map(|id| self.annotate(id, &[], parent.clone()));
visit::walk_struct_def(self, s, parent)
}
}
impl Index {
/// Construct the stability index for a crate being compiled.
pub fn build(krate: &Crate) -> Index {
let mut annotator = Annotator {
index: Index {
local: NodeMap::new(),
extern_cache: DefIdMap::new()
}
};
visit::walk_crate(&mut annotator, krate,
attr::find_stability(krate.attrs.as_slice()));
annotator.index
}
/// Lookup the stability for a node, loading external crate
/// metadata as necessary.
pub fn lookup(&mut self, cstore: &cstore::CStore, id: DefId) -> Option<Stability> {
if is_local(id) {
self.lookup_local(id.node)
} else {
let stab = csearch::get_stability(cstore, id);
self.extern_cache.insert(id, stab.clone());
stab
}
}
/// Lookup the stability for a local node without loading any external crates
pub fn lookup_local(&self, id: NodeId) -> Option<Stability> {
self.local.find_copy(&id)
}
}
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