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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use rustc::ast_map;
use rustc::lint::Context;
use rustc::middle::def;
use rustc::middle::def_id::DefId;
use syntax::ast;
use syntax::ast::{TyPath, Path, AngleBracketedParameters, PathSegment, Ty};
use syntax::attr::mark_used;
use syntax::ptr::P;
/// Matches a type with a provided string, and returns its type parameters if successful
///
/// Try not to use this for types defined in crates you own, use match_lang_ty instead (for lint passes)
pub fn match_ty_unwrap<'a>(ty: &'a Ty, segments: &[&str]) -> Option<&'a [P<Ty>]> {
match ty.node {
TyPath(_, Path { segments: ref seg, .. }) => {
// So ast::Path isn't the full path, just the tokens that were provided.
// I could muck around with the maps and find the full path
// however the more efficient way is to simply reverse the iterators and zip them
// which will compare them in reverse until one of them runs out of segments
if seg.iter().rev().zip(segments.iter().rev()).all(|(a, b)| a.identifier.name.as_str() == *b) {
match seg.last() {
Some(&PathSegment { parameters: AngleBracketedParameters(ref a), .. }) => {
Some(&a.types)
}
_ => None
}
} else {
None
}
},
_ => None
}
}
/// Checks if a type has a #[servo_lang = "str"] attribute
pub fn match_lang_ty(cx: &Context, ty: &Ty, value: &str) -> bool {
match ty.node {
TyPath(..) => {},
_ => return false,
}
let def_id = match cx.tcx.def_map.borrow().get(&ty.id) {
Some(&def::PathResolution { base_def: def::DefTy(def_id, _), .. }) => def_id,
_ => return false,
};
match_lang_did(cx, def_id, value)
}
pub fn match_lang_did(cx: &Context, did: DefId, value: &str) -> bool {
cx.tcx.get_attrs(did).iter().any(|attr| {
match attr.node.value.node {
ast::MetaNameValue(ref name, ref val) if &**name == "servo_lang" => {
match val.node {
ast::LitStr(ref v, _) if &**v == value => {
mark_used(attr);
true
},
_ => false,
}
}
_ => false,
}
})
}
// Determines if a block is in an unsafe context so that an unhelpful
// lint can be aborted.
pub fn unsafe_context(map: &ast_map::Map, id: ast::NodeId) -> bool {
match map.find(map.get_parent(id)) {
Some(ast_map::NodeImplItem(itm)) => {
match itm.node {
ast::MethodImplItem(ref sig, _) => sig.unsafety == ast::Unsafety::Unsafe,
_ => false
}
},
Some(ast_map::NodeItem(itm)) => {
match itm.node {
ast::ItemFn(_, style, _, _, _, _) => match style {
ast::Unsafety::Unsafe => true,
_ => false,
},
_ => false,
}
}
_ => false // There are probably a couple of other unsafe cases we don't care to lint, those will need
// to be added.
}
}
/// check if a DefId's path matches the given absolute type path
/// usage e.g. with
/// `match_def_path(cx, id, &["core", "option", "Option"])`
pub fn match_def_path(cx: &Context, def_id: DefId, path: &[&str]) -> bool {
cx.tcx.with_path(def_id, |iter| iter.map(|elem| elem.name())
.zip(path.iter()).all(|(nm, p)| &nm.as_str() == p))
}
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