use rustc::lint::{LintPass, LintArray, LateLintPass, LateContext};
use rustc::ty::{self, Ty};
use rustc::hir::Expr;
use syntax::ast;
use utils::{match_type, paths, span_lint};
declare_lint! {
pub MUTEX_ATOMIC,
Warn,
"using a mutex where an atomic value could be used instead"
}
declare_lint! {
pub MUTEX_INTEGER,
Allow,
"using a mutex for an integer type"
}
impl LintPass for MutexAtomic {
fn get_lints(&self) -> LintArray {
lint_array!(MUTEX_ATOMIC, MUTEX_INTEGER)
}
}
pub struct MutexAtomic;
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MutexAtomic {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
let ty = cx.tables.expr_ty(expr);
if let ty::TyAdt(_, subst) = ty.sty {
if match_type(cx, ty, &paths::MUTEX) {
let mutex_param = subst.type_at(0);
if let Some(atomic_name) = get_atomic_name(mutex_param) {
let msg = format!("Consider using an {} instead of a Mutex here. If you just want the locking \
behaviour and not the internal type, consider using Mutex<()>.",
atomic_name);
match mutex_param.sty {
ty::TyUint(t) if t != ast::UintTy::Us => span_lint(cx, MUTEX_INTEGER, expr.span, &msg),
ty::TyInt(t) if t != ast::IntTy::Is => span_lint(cx, MUTEX_INTEGER, expr.span, &msg),
_ => span_lint(cx, MUTEX_ATOMIC, expr.span, &msg),
};
}
}
}
}
}
fn get_atomic_name(ty: Ty) -> Option<(&'static str)> {
match ty.sty {
ty::TyBool => Some("AtomicBool"),
ty::TyUint(_) => Some("AtomicUsize"),
ty::TyInt(_) => Some("AtomicIsize"),
ty::TyRawPtr(_) => Some("AtomicPtr"),
_ => None,
}
}