servo/components/script/dom/cssmediarule.rs
JoeDow 6e6ef513a9
Reuse StylesheetContent for inline style sheets with identical content (#38540)
For duplicate style sheets with identical content, `StylesheetContents`
can be reused to avoid redundant parsing of the inline style sheets.
Since duplicate stylesheets is a common case with web components, this
change will significantly improve performance. Additionally, the cache
hit rate of stylo's `CascadeDataCache` can now be significantly
improved.

When shared `StylesheetContents` is modified, copy-on-write will occur
to avoid affecting other sharers. And then updates the references to
`CssRule` or `PropertyDeclarationBlock` stored in the CSSOMs to ensure
that modifications are made only on the new copy.

Signed-off-by: sharpshooter_pt <ibluegalaxy_taoj@163.com>
2025-08-20 12:31:49 +00:00

105 lines
3.5 KiB
Rust

/* 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 https://mozilla.org/MPL/2.0/. */
use std::cell::RefCell;
use dom_struct::dom_struct;
use servo_arc::Arc;
use style::shared_lock::{SharedRwLockReadGuard, ToCssWithGuard};
use style::stylesheets::{CssRuleType, MediaRule};
use style_traits::ToCss;
use crate::dom::bindings::codegen::Bindings::CSSMediaRuleBinding::CSSMediaRuleMethods;
use crate::dom::bindings::reflector::{DomGlobal, reflect_dom_object};
use crate::dom::bindings::root::{DomRoot, MutNullableDom};
use crate::dom::bindings::str::DOMString;
use crate::dom::cssconditionrule::CSSConditionRule;
use crate::dom::cssrule::SpecificCSSRule;
use crate::dom::cssstylesheet::CSSStyleSheet;
use crate::dom::medialist::MediaList;
use crate::dom::window::Window;
use crate::script_runtime::CanGc;
#[dom_struct]
pub(crate) struct CSSMediaRule {
cssconditionrule: CSSConditionRule,
#[ignore_malloc_size_of = "Arc"]
#[no_trace]
mediarule: RefCell<Arc<MediaRule>>,
medialist: MutNullableDom<MediaList>,
}
impl CSSMediaRule {
fn new_inherited(parent_stylesheet: &CSSStyleSheet, mediarule: Arc<MediaRule>) -> CSSMediaRule {
let list = mediarule.rules.clone();
CSSMediaRule {
cssconditionrule: CSSConditionRule::new_inherited(parent_stylesheet, list),
mediarule: RefCell::new(mediarule),
medialist: MutNullableDom::new(None),
}
}
#[cfg_attr(crown, allow(crown::unrooted_must_root))]
pub(crate) fn new(
window: &Window,
parent_stylesheet: &CSSStyleSheet,
mediarule: Arc<MediaRule>,
can_gc: CanGc,
) -> DomRoot<CSSMediaRule> {
reflect_dom_object(
Box::new(CSSMediaRule::new_inherited(parent_stylesheet, mediarule)),
window,
can_gc,
)
}
fn medialist(&self, can_gc: CanGc) -> DomRoot<MediaList> {
self.medialist.or_init(|| {
MediaList::new(
self.global().as_window(),
self.cssconditionrule.parent_stylesheet(),
self.mediarule.borrow().media_queries.clone(),
can_gc,
)
})
}
/// <https://drafts.csswg.org/css-conditional-3/#the-cssmediarule-interface>
pub(crate) fn get_condition_text(&self) -> DOMString {
let guard = self.cssconditionrule.shared_lock().read();
self.mediarule
.borrow()
.media_queries
.read_with(&guard)
.to_css_string()
.into()
}
pub(crate) fn update_rule(&self, mediarule: Arc<MediaRule>, guard: &SharedRwLockReadGuard) {
self.cssconditionrule
.update_rules(mediarule.rules.clone(), guard);
if let Some(medialist) = self.medialist.get() {
medialist.update_media_list(mediarule.media_queries.clone());
}
*self.mediarule.borrow_mut() = mediarule;
}
}
impl SpecificCSSRule for CSSMediaRule {
fn ty(&self) -> CssRuleType {
CssRuleType::Media
}
fn get_css(&self) -> DOMString {
let guard = self.cssconditionrule.shared_lock().read();
self.mediarule.borrow().to_css_string(&guard).into()
}
}
impl CSSMediaRuleMethods<crate::DomTypeHolder> for CSSMediaRule {
// https://drafts.csswg.org/cssom/#dom-cssgroupingrule-media
fn Media(&self, can_gc: CanGc) -> DomRoot<MediaList> {
self.medialist(can_gc)
}
}