servo/components/script_plugins/ban.rs

/* 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::lint::{EarlyContext, LintPass, LintArray, EarlyLintPass, LintContext};
use syntax::ast::Ty;
use utils::match_ty_unwrap;

declare_lint!(BANNED_TYPE, Deny,
              "Ban various unsafe type combinations");

/// Lint for banning various unsafe types
///
/// Banned types:
///
/// - `Cell<JSVal>`
/// - `Cell<JS<T>>`
pub struct BanPass;

impl LintPass for BanPass {
    fn get_lints(&self) -> LintArray {
        lint_array!(BANNED_TYPE)
    }
}

impl EarlyLintPass for BanPass {
    fn check_ty(&mut self, cx: &EarlyContext, ty: &Ty) {
        if match_ty_unwrap(ty, &["std", "cell", "Cell"])
            .and_then(|t| t.get(0))
            .and_then(|t| match_ty_unwrap(&**t, &["dom", "bindings", "js", "JS"]))
            .is_some() {
            cx.span_lint(BANNED_TYPE, ty.span, "Banned type Cell<JS<T>> detected. Use MutJS<JS<T>> instead")
        }
        if match_ty_unwrap(ty, &["std", "cell", "Cell"])
            .and_then(|t| t.get(0))
            .and_then(|t| match_ty_unwrap(&**t, &["js", "jsval", "JSVal"]))
            .is_some() {
            cx.span_lint(BANNED_TYPE, ty.span, "Banned type Cell<JSVal> detected. Use MutJS<JSVal> instead")
        }
        if match_ty_unwrap(ty, &["dom", "bindings", "cell", "DOMRefCell"])
            .and_then(|t| t.get(0))
            .and_then(|t| match_ty_unwrap(&**t, &["dom", "bindings", "js", "JS"]))
            .is_some() {
            cx.span_lint(BANNED_TYPE, ty.span, "Banned type DOMRefCell<JS<T>> detected. Use MutJS<JS<T>> instead")
        }
        if match_ty_unwrap(ty, &["dom", "bindings", "cell", "DOMRefCell"])
            .and_then(|t| t.get(0))
            .and_then(|t| match_ty_unwrap(&**t, &["js", "jsapi", "Heap"]))
            .is_some() {
            cx.span_lint(BANNED_TYPE, ty.span, "Banned type DOMRefCell<Heap<T>> detected. Use Heap<T> directly instead")
        }
    }
}