servo/components/script/dom/cssstylerule.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 dom::bindings::codegen::Bindings::CSSStyleRuleBinding::{self, CSSStyleRuleMethods};
use dom::bindings::inheritance::Castable;
use dom::bindings::js::{JS, MutNullableJS, Root};
use dom::bindings::reflector::{DomObject, reflect_dom_object};
use dom::bindings::str::DOMString;
use dom::cssrule::{CSSRule, SpecificCSSRule};
use dom::cssstyledeclaration::{CSSModificationAccess, CSSStyleDeclaration, CSSStyleOwner};
use dom::cssstylesheet::CSSStyleSheet;
use dom::window::Window;
use dom_struct::dom_struct;
use parking_lot::RwLock;
use std::sync::Arc;
use style::shared_lock::ToCssWithGuard;
use style::stylesheets::StyleRule;

#[dom_struct]
pub struct CSSStyleRule {
    cssrule: CSSRule,
    #[ignore_heap_size_of = "Arc"]
    stylerule: Arc<RwLock<StyleRule>>,
    style_decl: MutNullableJS<CSSStyleDeclaration>,
}

impl CSSStyleRule {
    fn new_inherited(parent_stylesheet: &CSSStyleSheet, stylerule: Arc<RwLock<StyleRule>>)
                     -> CSSStyleRule {
        CSSStyleRule {
            cssrule: CSSRule::new_inherited(parent_stylesheet),
            stylerule: stylerule,
            style_decl: Default::default(),
        }
    }

    #[allow(unrooted_must_root)]
    pub fn new(window: &Window, parent_stylesheet: &CSSStyleSheet,
               stylerule: Arc<RwLock<StyleRule>>) -> Root<CSSStyleRule> {
        reflect_dom_object(box CSSStyleRule::new_inherited(parent_stylesheet, stylerule),
                           window,
                           CSSStyleRuleBinding::Wrap)
    }
}

impl SpecificCSSRule for CSSStyleRule {
    fn ty(&self) -> u16 {
        use dom::bindings::codegen::Bindings::CSSRuleBinding::CSSRuleConstants;
        CSSRuleConstants::STYLE_RULE
    }

    fn get_css(&self) -> DOMString {
        let guard = self.cssrule.shared_lock().read();
        self.stylerule.read().to_css_string(&guard).into()
    }
}

impl CSSStyleRuleMethods for CSSStyleRule {
    // https://drafts.csswg.org/cssom/#dom-cssstylerule-style
    fn Style(&self) -> Root<CSSStyleDeclaration> {
        self.style_decl.or_init(|| {
            CSSStyleDeclaration::new(self.global().as_window(),
                                     CSSStyleOwner::CSSRule(JS::from_ref(self.upcast()),
                                                            self.stylerule.read().block.clone()),
                                     None,
                                     CSSModificationAccess::ReadWrite)
        })
    }
}